cycling
and control
of metals
U.S. ENVIRONMENTAL PROTECTION AGENCY
NATIONAL ENVIRONMENTAL
RESEARCH CENTER
Cincinnati, Ohio
-------
CYCLING and
CONTROL of METALS
PROCEEDINGS OF AN ENVIRONMENTAL
RESOURCES CONFERENCE
SPONSORED BY:
U. S. Environmental Protection Agency
National Science Foundation
Columbus Laboratories of
Battelle Memorial Institute
October 31 - November 2, 1972
Columbus, Ohio
Compilers:
Marion G. Curry
Gilbert M. Gigliotti
National Environmental Research Center, Cincinnati
February 1973
-------
PREFACE
This volume is based on a conference held October 31
through November 2, 1972,in Columbus, Ohio. Each of
the five sessions of the conference was designed to bring
together knowledge and thinking in areas bearing on the
problem of metals and their relationship to the environ-
ment.
Considering the sources of tracer metals in the envi-
ronment was only part of the story. Transport and
effects, control processes, monitoring for trace metals,
and the economic and legal aspects of pollution were
also discussed.
The conference was sponsored by the U. S. Environ-
mental Protection Agency's National Environmental
Research Center, Cincinnati, National Science Founda-
tion, and the Columbus Laboratories of Battelle
Memorial Institute.
We wish to express our gratitude to the many who
contributed to the success of the Conference.
Publication of the papers by the U. S. Environmental
Protection Agency does not imply endorsement of either
the conclusions or any commercial product mentioned in
the papers.
The Chairmen
ui
-------
CONFERENCE COMMITTEE
Co-Chairmen
A. W. Breidenbach C.J.Lyons R.Rabin
National Environmental Battelle-Columbus National Science
Research Center USEPA Laboratories Foundation
Planning Committee
National Environmental Battelle-Columbus
Research Center, USEPA Laboratories
J. J. Convery G. A. Lutz
L. J. McCabe D. L. Morrison
I. Wilder R. G. Smithson, Jr.
IV
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CONTENTS
KEYNOTE REMARKS
Metals: Parts and the Whole .... . . .1
A. W. Breidenbach, U. S. Environmental Protection Agency
SESSION I: SOURCE OF TRACE METALS IN THE ENVIRONMENT
Chairman: A. W. Breidenbach, U. S. Environmental Protection Agency
Natural Sources of Some Trace Elements in the Environment 3
M. Fleischer, U. S. Geological Survey
The Lead Industry as a Source of Trace Metals in the Environment 11
B. G. Wixson, E. Bolter, N. L. Gale, J. C. Jennett, and K. Purushothaman, University of Missouri
Sources of Trace Metals From Highly Urbanized Southern California to the Adjacent Marine Ecosystem 21
D. R. Young, C-S. Young, and G. E. Hlavka, Southern California Coastal Water Research Project
LUNCHEON ADDRESS
Overview of Effects of Trace Metals . 41
H. A. Laitinen, University of Illinois
SESSION n: TRANSPORT AND EFFECTS
Chairman: H. Wiser, U. S. Environmental Protection Agency
Physical Transport of Trace Metals in the Lake Washington Watershed ... 45
R. S. Barnes and W. R. Schell, University of Washington
Biological Uptake and Distribution of Lead in Animals .... 55
J. Abdelnour, University of Illinois
PANEL DISCUSSION: EFFECTS AND ESTABLISHMENT OF CRITERIA
Effects and Development of Criteria and the Establishment of Standards 61
H. Wiser, U. S. Environmental Protection Agency
Effects and Establishment of Criteria .... . . . 63
T. E. Larson, Illinois State Water Survey
Human Studies Laboratory 67
G. J. Love, U. S. Environmental Protection Agency
Significant Effect of Pollutants ... . 69
J. F. Cole, International Lead Zinc Research Organization, Inc.
Statement on Establishment of Criteria for Metals in Foods 71
C. F. Jelinek, U. S. Department of Health, Education, and Welfare
-------
Biomedical Research in Support of Criteria and Standards . . 73
D. H. K. Lee, U. S. Department of Health, Education, and Welfare
SESSION HI: CONTROL PROCESSES
Chairman: C. J. Lyons, Battelle's Columbus Laboratories
Trace Metals in Effluents From Metallurgical Operations 75
J. B. Hallowell, R. H. Cherry, Jr., and G. R. Smithson, Jr., Battelle's Columbus Laboratories
Pollution Abatement in the Metal Finishing Industry . . . . 83
J. Ciancia, U. S. Environmental Protection Agency
Control and Prevention of Mine Drainage . 91
R. D. Hill, U. S. Environmental Protection Agency
Control of Particulate Lead Emissions From Automobiles ... 95
E. N. Cantwell, E. S. Jacobs, W. G. Kunz, Jr., and V. E. Liberi, E. I. duPont deNemours & Co.
Trace Element Emissions From the Combustion of Fossil Fuels . . 109
J. R. Fancher, Commonwealth Edison Co.
LUNCHEON ADDRESS
Luncheon Remarks. . . 115
Martin Lang, City of New York
SESSION IV: MONITORING FOR TRACE METALS IN THE ENVIRONMENT
Chairman: R. Rabin, National Science Foundation
Monitoring Session: Chairman's Opening Remarks .... .121
R. Rabin, National Science Foundation
Monitoring for Trace Metals in the Atmospheric Environment: Problems and Needs . 123
P. R. Harrison, Department of Environmental Control
Monitoring for Trace Metals—Water Environment . . . . 145
D. G. Ballinger, U. S. National Environmental Research Center
Monitoring of Solid Wastes ...... . .149
E. A. Glysson, University of Michigan
Monitoring for Trace Metals in Food . . ... . . . 153
E. 0. Haenni, U. S. Department of Health, Education, and Welfare
Dimensions of Monitoring ... 159
R. P. Ouellette and J. W. Overbey II, The MITRE Corp.
SESSION V: ECONOMIC AND LEGAL ASPECTS
Chairman: G. Strasser, Battelle's Columbus Laboratories
Economic and Legal Aspects 167
G. Strasser, Battelle's Columbus Laboratories
The Social Implication of Controls 169
P. Mickey, Concern, Inc.
How Much Recycling Is Enough? 173
T. Page, Resources for the Future, Inc.
Law and Trace Metals 179
E. F. Murphy, Ohio State University
-------
KEYNOTE REMARKS
A. W. Breidenbach
U. S. Environmental Protection Agency
-------
KEYNOTE REMARKS
METALS: PARTS AND THE WHOLE
A. W.BREIDENBACH
U. S. Environmental Protection Agency
Cincinnati, Ohio
INTRODUCTION
For a few short hours we have come together this
week to look at the subject of metals and their
relationship to the environment. Metals are an apt
subject since they claim the attention of the chemist,
physicist, engineer, biologist, physician, statistician,
mathematician, economist, and politician. They also
pervade the air, the water, and the land. Their
deficiencies and overabundances are important to plants,
animals, and most importantly, man.
Metals are elements that have a typical luster and that
carry a positive charge. The electrolytic chemist defines
metals as those substances that are liberated at the
cathode. The mining engineer will think of extractable
ores; the civil engineer of structural steel. Other
recognizable characteristics of metals are their high
melting temperatures, low specific heat, good
themoelectrical conductivity, hardness, and inability to
be deformed permanently without fracture.
Metals and alloys representing mixtures of metals are
identified and classified by their chemical, physical, and
mechanical properties. Some combination of these three
properties usually determines the metal chosen for a
specific function. Strength, malleability, and resistance
to corrosion are important characteristics of metals in
engineering and physical arenas. We all know that gold,
silver, platinum, bronze, brass, copper, aluminum, and
stainless steel have utility, in addition to certain
aesthetic values we appreciate.
We find that the entire plant and animal kingdoms
depend on metals in a variety of ways. For example, the
blood that flows through our circulation system carrying
oxygen to our cells and removing the waste carbon
dioxide depends heavily on an atom of iron incorporated
into the hemoglobin of the red corpusle. Textbooks on
biochemistry or physiology relate that a large group of
metals are active within the dynamics of protein
anabolism and catabolism. Iron, cobalt, manganese,
copper, and magnesium and many other metals are
essential to the structure of metalo-proteins. More
specifically, the enzymes that catalyze various
biochemical reactions within plant and animal systems
are often either activated by metals or contain metal.
Although plants and animals need metals, they don't
need too much of them. For instance, some scholars
implicate an overabundance of lead in the fall of the
Roman Empire. The eastern Romans used leaden pots to
contain their wine, and they reduced the acidity of wine
by adding lead oxide to it. The lead poisoning that
followed brought about widespread stillbirths,
deformities, and brain damage, particularly among the
upper classes who obviously had greater access to lead
vessels — and to the wine. Some support for this theory
comes from the high lead content found in the bones of
some ancient Romans. Such accounts, even if
speculative, give us some concern over the level of blood
lead in the earth's human population, which presently
lies between 0.05 and 0.4 parts per million, averaging
about 0.25 parts per million. Recent proposals indicate
that the toxic threshold level of lead in the blood should
be reduced from 0.8 to 0.5 ppm for classical lead
poisoning. Despite increased environmental levels, the
decrease from earlier high levels is probably resulting
from the greater precautions in the use of lead.
Metal deficiencies result in illnesses. In the same way
that an overabundant intake of metal results in toxic
reactions. The various forms of life on the planet
obviously require a variety of metals in various
concentrations. We all know now that trace elements are
needed in our diets and that we feed our lawns 10 parts
of nitrogen, 10 parts of phosphorus, and 10 parts of
potassium in the spring. Controlling the intake of metal
in our food and water as well as its intake by other
animals and plants in the ecological system becomes an
important environmental responsibility.
Most of the metal that we use as inhabitants of the
earth comes from the crust of the earth. The most
important elements, which accounts for about 90% of all
-------
CYCLING AND CON7TROL OF METALS
the metal used, is iron. The most abundant, accounting
for 28%, is silica. AJthough many metals exist in the
earth's crust at quantities of less than one thousandth of
a percent, a plentiful supply is related to much of
today's pollution. The excess or overabundance that
causes toxicity in man and animals can be the cause of
pollution on the earth, since abundances, somehow,
encourage wastage.
The processes, coflectively known as mining, that
remove metals from the earth's crust, cause the influx of
heavy metals, acid, sediment, and mineralized water,
which degraded over 10,000 miles of streams.
Approximately 45 million acres are disturbed yearly
and this number is expected to increase because of the
increasing demand for power and metals. After the ore is
removed, it must be processed and refined so that the
purer form of the metal can ultimately be used to
fabricate needed objects and structures. Although the
processing and refining operations for the various metals
differ widely, these processes have, in the past,
contributed greatly to our air pollution, water pollution,
and our solid waste problems.
Contrary to popular opinion, concern about the
environment has been with us for over six decades. The
Federal Government's role in stream pollution control
began in 1913 on the northern bank of the Ohio River at
Cincinnati. The substantive legislation that implemented
broad water pollution control programs was enacted.
almost three decades ago, in 1946. Air pollution work
began in the 50's. The problems of the management and
utilization of wasted solids, which came to the forefront
in the 1960's, are present with us in the 70's and
promise to claim our attention in the 80's and 90's.
There are certain comfortable personal advantages for
the scientist conducting research within the various
environmental compartments. Research confined to a
narrow avenue can produce sound defensible data, which
we need. But this kind of research alone, multiplied by
the many scientists who pursue it, may never give us the
holistic view of the environment we need to make true
progress. I am now convinced that these compartments,
air, water, solid waste, pesticide, radiation, noise, etc.,
cannot be considered independently of one another. The
interrelationships between various environmental
segments must receive paramount consideration, not
only at the level of the research administrator but also
by the scientists who conduct research and exchange
information in conferences. Man does not live only on a
river or only in the air. He is not exposed just to
radiation or just to pesticides. Environmental insults
occur through all routes: air, water, and food. Man sees
it, hears it, feels it, tastes it,and smells it. He inhales it,
ingests it, and exposes his skin and mucous membranes
to it. He works in it, plays in it, and sleeps in it.
Our task is certainly cut out for us. We have a
storehouse of metals present in the earth and available
for our use for centuries to come. We must develop a
stewardship in the use of these resources that avoids the
difficulties of high and low exposures to life forms and
encourages reclaimation, re-use, and recycling for the
ultimate benefit of other generations yet to live on this
planet. We must be cautious about the manner in which
we mine, process, fabricate, use, and discard these
materials. We need a positive plan that will permit the
maximum advantage to mankind in the re-use of metallic
resources.
Perhaps here in Columbus, we as scientists interested in
particular impacts of metals can begin to build a total
solution to an environmental problem from our
individual data, information, and experience.
-------
SESSION I
SOURCE OF TRACE METALS
IN THE ENVIRONMENT
Chairman:
A. W. Breidenbach
U. S. Environmental Protection Agency
-------
NATURAL SOURCES OF SOME TRACE ELEMENTS
IN THE ENVIRONMENT
M. FLEISCHER
U. S. Geological Survey
Washington, D. C.
INTRODUCTION
Increasing concern over possible hazards to health
caused by trace metals, has led to the realization that we
need to know much more about their natural and man
made sources, their transport under natural conditions,
and their entire cycle in the lithosphere, hydrosphere,
biosphere, and atmosphere. Since it is necessary to
restrict the discussion, data are presented for four
elements: lead, cadmium, arsenic, and mercury, in the
commonest types of rocks. Emphasis is placed on rocks
in which these elements have been concentrated and
rocks that are treated by man in ways that the elements
might enter the environment in amounts sufficient to
affect health.
Average concentrations of these elements in the
continental crust, such as those listed in the tables of
this paper, represent material generally estimated to
consist of about 95% igneous and metamorphic rocks,
and about 5% of sedimentary rocks. Detailed estimates
of the proportions of various types of igneous and
sedimentary rocks have been reviewed (1 3). The
distribution patterns of trace elements have been
reviewed in several papers in a recent monograph (4).
Igneous rocks, formed by the solidification of melts,
constitute most of the continental crust, which is
generally considered to be composed mainly of a 2 to 1
ratio of silicic types and basaltic types. The silicic types
include the granites and granodiorites that form large
plutons such as those of the Sierra Nevada and Idaho
batholiths, and also the extrusive rhyolites. Rocks of
basaltic type which form the large-scale lava flows of the
Columbia and Snake River Basins are the major
constituent of the sub-oceanic crust.
The behavior of the trace elements during the
formation of the igneous rocks is predictable to a
considerable degree from their crystallochemical
relations to the major elements of the crystallizing
minerals. Nickel and chromium follow magnesium
closely and are concentrated in the magnesium-rich
ultramafic rocks that are hosts for the major ores of
chromium. The minerals of basaltic rocks concentrate:
Cu, Zn, and V. Those of granitic rocks concentrate the
large cations: K, Ba, Pb, the lanthanides, Zr, U, and Th
and the very small ones, Be.
At various stages of igneous processes, by mechanisms
that are still in dispute, sulfur-rich fluids separate and
form the sulfide deposits. Although these constitute a
very small fraction of the Earth's crust, they are the
principal ores of Cu, Zn, Pb, Hg, Sb, and Mo, and the
major sources of the byproduct trace metals Ag, Cd, T£,
In, Ge, and Re.
Rocks at or near the surface of the Earth are subjected
to the chemical attack of the atmosphere and ground
waters. Water, CO2, oxygen, and organic compounds are
the principal reagents. The reactions are affected by: the
composition of the original rocks, pH, the oxidation
potential, and the activity of plants, animals, and
microbes. The constitutent minerals of the original rocks
may be altered to other minerals, or may be dissolved
partially or completely, either to precipitate elsewhere,
or to be carried to the ocean. The sediments of these
minerals are the major scavengers of trace elements on
our planet. Fortunately, practically all the trace
elements reaching the ocean do not remain in solution,
except B, Br, and Se. More than 99 percent are
deposited in the oceanic sediments (5, 6).
Although they constitute only 5 percent of the
continental crust of the earth, the sedimentary rocks and
soils are of far greater importance to man than their
magnitude would indicate for two reasons: (a) they
constitute a large part of the material exposed at the
surface, and (b) they are the materials from which plants
and animals derive their food. Shales and clays are the
most important sedimentary rocks. Estimates of the
relative abundances of the types of sedimentary rocks
differ; shales and clays 5j 77 percent, sandstones^ 15
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CYCLING AND CONTROL OF METALS
percent, limestones and dolomites 7.5 to 8 percent (7).
Where the sedimentary rocks are fine-grained,
adsorption plays an important role in the concentration
of trace elements. In addition, sedimentary rocks which
are rich in organic matter, especially the carbonaceous
shales, preferentially concentrate many elements,
including Hg, As, Mo, Ge, V, and U. The mechanism of
concentration is poorly understood, despite its
importance (8).
Chemical weathering has produced many of our most
important ore deposits. Examples are sedimentary
aluminum, iron and manganese oxides, the nickel
silicates, and the placer concentrates of minerals that
resist breakdown during weathering. The latter are major
source of Ti (as rutile and as ilmenite), Zr (as zircon),
the lanthanides and Th (as monazite), Au, and the Pt
metals. The marine phosphorites, chemical precipitates
from the oceans, are notable concentrators of many
trace elements, including U, V, the lanthanides, As, Zn,
Cd, and Hg (9). Finally, mention must be made of coal
and petroleum, the natural transformation products of
plant material, in which many trace elements are
present.
In the summaries that follow concerning the
distribution of lead, cadmium, arsenic, and mercury,
particular attention is directed towards concentrations
of these elements in natural materials whose present uses
(coal, phosphorite, sedimentary iron ores) or possible
future uses (oil shale) could cause environmental
problems. Data on trace element contents of coal and
petroleum are summarized (10), and on black shales
(11). All four of these elements are produced
commercially from sulfide ores.
Data on concentrations of lead, cadmium, arsenic,
and mercury in surface waters of the United States are
also summarized. The figures are given for the resultant
of the amounts of these elements is the sum of the
elements derived from weathering plus those introduced
by volcanic emanations plus those introduced into the
environment by man's activities.
LEAD
Data on the abundance of lead in natural materials are
summarized in Table 1. The element is rather uniformly
distributed in these materials, with some degree of
concentration in clayey sediments. It is highly
concentrated in sulfide deposits.
Data on the concentrations of lead in filtered surface
waters of the United States are summarized in Table 2.
The amount introduced into the ocean by chemical
weathering of rocks is appreciable (6, 10), but is less
than the amount of lead emitted to the atmosphere in
the United States alone (12), and far less than the annual
consumption of lead. It seems safe to estimate that more
than 90 percent of the lead discharged into the
atmosphere and streams can be ascribed to man-made
sources.
TABLE 1 CONCENTRATIONS OF LEAD IN SOME
NATURAL MATERIALS, PPM
Type of
material
Continental crust
Basaltic igneous
Silicic igneous
Shales and clays
Black shales (high C)
Deep sea clays
Limestones
Sandstones
Soils
Phosphorites
Coals
Range usually
reported
—
2- 18
6- 30
16- 50
7-150
-
-
< 1- 31
1-150
<10-100
2- 50
Average
15
6
18
20
30
80
9
15
10
15
TABLE 2 DISSOLVED LEAD IN SURFACE WATERS
OF THE U. S.
(See Reference 13)
Microg/liter % of
(~ ppb Pb) 717 samples
< 1
1- 4
5- 9
10-19
20-29
30-79
> (max. 80)
35.8
33.9
15.8
9.8
2.9
1.5
0.3
CADMIUM
Data on the abundance of cadmium in natural
materials are summarized in Table 3; the geochemistry
of cadmium has been reviewed (14). Cadmium is a
relatively rare element being concentrated in
zinc-bearing sulfide ores (ratio Zn/Cd usually 100 to
200) and consequently in all zinc-containing
manufactured products.
It is somewhat concentrated in shales and clays and is
notably concentrated in phosphorites. Consequently, it
is present in manufactured phosphate fertilizers.
Most fresh waters contain less than 1 ppb Cd. The
chemistry of cadmium and zinc in surface and ground
waters has been reviewed recently (15), giving
calculations of equilibrium solubilities with the
hydroxide or carbonate as solid phase. Most waters were
unsaturated with respect to these phases. About 20
percent had cadmium contents in reasonable agreement
with solubilities calculated assuming CdCOs as
equilibrium solid phase. Analyses of sea water average
about 0.15 microg/1. (~ppb).
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TRACE METALS - NATURAL SOURCES
TABLE 3 CONCENTRATIONS OF CADMIUM IN
SOME NATURAL MATERIALS, PPM
Type of
material
Continental crust
Basaltic igneous
Silicic igneous
Shales and clays
Black shales (high C)
Deep sea clays
Limestones
Sandstones
Soils
Phosphorites
Coals
Range usually
reported
_
0.006-
0.003-
0
0.5 -
0.1 -
-
-
0.1 -
0.6
0.18
11
8.4
1
0.5*
0 -170
—
Average
0.2
0.2
0.15
1.4
2.0
0.5
0.05
0.05
0.3*
30
2
TABLE 5 CONCENTRATIONS OF ARSENIC IN
SOME NATURAL MATERIALS, PPM
*Excluding soils from mineralized areas.
Table 4 summarizes data on surface waters of the
United States. Concentrations above natural background
are almost certainly due to industrial waste. Even higher
concentrations (up to 450 ppb Cd) have been reported
in the South Fork of the Coeur d'Alene River in Idaho
(16), a stream that drains an area containing extensive
dumps of ground mill tailings from Pb-Ag-Zn ores.
As with lead, it seems safe to estimate that more than
90 percent of the cadmium discharged to the
atmosphere and streams in the environment can be
ascribed to man-made sources.
ARSENIC
Data on the concentrations of arsenic in natural
materials, recently reviewed (17), are summarized in
Table 5. Arsenic is especially concentrated in sulfide
ores, predominantly as arsenopyrite (FeAsS), but also as
a constituent of many complex sulfides of copper and
lead, .such as enargite and tennantite. Arsenic is
concentrated in shales, clays, phosphorites, coals,
TABLE 4 CADMIUM IN FILTERED SURFACE
WATERS OF THE U. S.
(See Reference 13)
Microg/liter
(~PPbCd)
%of
727 samples
< 1 54.2
1- 4 32.3
5- 9 7.7
USPH upper limit
10- 20 4.1
21- 40 0.9
41-130 0.8
Type of
material
Continental crust
Basaltic igneous
Silicic igneous
Shales and clays
Deep sea clays
Limestones
Sandstones
Soils
Phosphorites
Sedimentary Fe ores
Sedimentary Mn ores
Range usually
reported
—
0.2- 10
0.2- 13.8
-
-
0.1- 8.1
0.6- 9.7
0 - 102*
0.4-2000
70 -1100
up to 1.5%
Average
2.0
2.0
2.0
10.
13.
1.7
2
5*
13
400
-__
100.0
*Exeluding soils from mineralized ares
sedimentary iron, and manganese ores. Industrial
processes using these materials supply considerable
amounts of arsenic to the atmosphere and to surface
waters. Another possible source is petroleum. Recent
analyses show 0.005 to 1.1 (median 0.09) ppm As, but
there are few analyses.
Most of the arsenic in non-marine shales is associated
with the clay minerals, whereas in offshore marine
samples a considerable proportion of the arsenic is
present in pyrite FeS2 (18). The arsenic in coal may also
be present in pyrite. Strong positive correlation between
the contents of arsenic and of organic carbon have been
found for the Pierre Shale (19), and for unconsolidated
sediments of Lake Michigan (20). The latter had much
higher arsenic contents in the near-surface sediments (0
to 6 cm.) than in those at depths greater than 20 cm.
(12.4 vs. 5.3 ppm). This indicates a recent increase in the
proportion due to man's activities.
In the manufacture of superphosphate fertilizer by
treatment of phosphorite with sulfuric acid, most of the
arsenic present in the phosphorite passes into the
manufactured fertilizer. If the sulfuric acid used is made
from sulfide ores, it is likely to contain considerable
arsenic. Superphosphate made in this way has been
reported to contain up to 0.1 percent As.
Data on filtered surface waters of the United States
are summarized in Table 6. The concentrations of
arsenic are evidently due, in part, to industrial
contamination, and probably, in part, to urban wastes
such as high-phosphate detergents (21). It should be
noted that fumarolic gases associated with volcanism
have been reported to contain up to 0.7 ppm As and
that waters of hot springs contain up to 13.7 ppm As.
Most ground waters are low in arsenic, averaging perhaps
1 ppb As, but concentrations high enough to endanger
health (22), have been reported often enough to warrant
concern.
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CYCLING AND CONTROL OF METALS
TABLE 6 DISSOLVED ARSENIC IN FILTERED
SURFACE WATERS OF THE U. S.
(See Reference 13)
Microg/liter % of
(~ ppb As) 728 samples
< 10
10- 19
20- 29
30- 49
76.8
15.8
3.5
2.5
USPHS upper limit
50- 99 1.1
100-1100 0.3
100.0
Although quantitive data is lacking, it has been
suggested that microbial action, under highly'reducing
natural conditions, might lead to the formation of arsine
or other volatile arsenic compounds.
Although data are insufficient for an estimate of
magnitude, it seems probable that the natural sources
mentioned, including the erosion of surface rocks, may
account for a significant portion of the discharge of
arsenic to the atmosphere and streams.
MERCURY
Recent concern over the health hazards of mercury
has triggered much research on its geochemistry,
including the appearance of reviews (23—25).
Nevertheless, the average abundances listed in Table 7
are much more uncertain than those for the elements
previously discussed. This is due in part because of the
TABLE 7 CONCENTRATIONS OF MERCURY IN
SOME NATURAL MATERIALS, PPM
Type of
material
Continental crust
Basaltic igneous
Silicic igneous
Shales and clays
Black shales (high C)
Deep sea clays
Limestones
Sandstones
Soils
Phosphorites
Coals
Range usually
reported
—
0.002- 0.5 *
0.005- 0.4 *
0.005- 1.0 *
0.03 - 2.8
0.02 - 2.0
0.01 - 0.22*
0.001- 0.3 *
0.001- 0.5 f
0.001- 0.95
0.05 -13.3 *
Average
0.06
0.05 *
0.06 *
0.16 *
0.5
0.4
0.04 *
0.05 *
0.05 f
0.050
0.3 *
difficulty of analysis for such low concentrations, and
because of the uncertainty caused by the very high
concentrations reported in some areas of the world (23).
Some of the estimates in Table 7, especially those for
shales, deep sea clays, and coals are higher than previous
estimates and may still be too low, on shales, (26); on
river, lake, and ocean sediments (27—35). The cycle of
mercury in the environment has been reviewed (36).
Mercury is concentrated in sulfide ores, especially
those of zinc and to a lesser extent in those of copper.
The determination of mercury has been widely used as a
tool in geochemical prospecting for such ore deposits. It
is notably concentrated in shales and clays, especially
those rich in organic matter, in some phosphorites, and
in coal (20, 37-40). Up to 2.9 ppm Hg has been
reported in petroleum, but there are too few analyses to
permit an estimate of the environmental impact.
Mercury can reach the environment from all these
sources, either by the action of chemical weathering or
during industrial processing. Mercury differs from the
other elements in two important respects. First, its vapor
pressure, even at surface temperatures, is so high that
direct volatilization to the atmosphere is significant (see
Table 9). A very high proportion of the mercury present
in coal is volatilized during burning. Second, it is now
well established that the mercury in fluvial and
lacustrine sediments can be converted, by microbial
action, into organic mercury compounds (methyl
mercury). These compounds are partly volatilized and
partly taken up by living matter, especially fish;
reintroducing them to the environment.
Data on the concentrations of mercury in filtered
surface waters of the U.S. are summarized in Table 8.
The available evidence indicates that most of the
mercury reaching streams, lakes, and the ocean is
precipitated rapidly.
Mercury is a constituent of volcanic emanations (Table
9) and of fumarolic vapors and hot springs associated
with volcanic emanations. Although data are insufficient
TABLE 8 DISSOLVED Hg IN FILTERED SURFACE
WATERS OF THE U. S.
(See References 13 and 41)
Microg/liter % of
(~ ppb Hg) 706 samples
<0.5
0.1- 0.4
0.5- 2.0
2.0- 4.9
52,1
21.8
15.7
5.8
*Nol including many analyses, especially from the Donets
Basin. Kerch-Taman area, and Crimea, USSR, that show
contents 10-1000 times the average given.
fExcluding soils from mineralized areas
EPA upper limit
5.0- 9.9 2.0
11-0-19.9 ].6
> 20 (max. 740) 1.0
100.0 '"
-------
TRACE METALS - NATURAL SOURCES
TABLE 9 MERCURY IN AIR AND IN VOLCANIC EMANATIONS, (IN
NANOGRAMS PER CUBIC METER) (1 NANOGRAM=l(r9 g.)
Sample
Range
AIR
Over Pacific Ocean, 20 miles offshore
Arizona and Calif., unmineralized areas
California
Chicago area
Moscow and Tula regions, USSR
400 ft. above porphyry copper deposits, USA
400 ft. above mercury deposits, USA
Over mercury deposit, USSR
0.6-0.7
3-9
1-50
3-39
80-300
7-53
24-108
200-1200
AIR and GASES, volcanic regions
Air, Kamchatka region, USSR
Air, Honolulu, Hawaii
Air, Sulfur Banks, Kilauea Volcano
Air, vent breccias of mud volcanoes USSR
Gases, mud volcanoes USSR
Gases, Mendeleev, and Sheveluch Volcanoes, USSR
Gases from hot springs, Kamchatka and Kuriles
40-910*
21,400-23,300*
300-700
700-2000
300-4000
10,000-18,000
"Data source reference 42.
to permit quantitative estimates, the very large amount
of material involved, especially the emanations from
mud volcanoes, indicates the proportion of mercury
reaching the atmosphere and waters from natural sources
must be high; possible of the order of 30 to 70 percent
of the total.
A recent study (27) (see Figure 1) gives data on the
mercury contents of a drill core taken from the
Average
9.7
27
60
190
sediments of southeastern Lake Ontario, which show a
spectacular increase of mercury from 1906 to the
1940's. From these data, the present daily input of
mercury into Lake Ontario is estimated to be 42 Ib. (19
kg.) Hg from natural sources and 83 Ib (37.6 kg) from
industrial sources (27). In this industrialized area, man's
activities supply about two-thirds of the mercury.
-------
CYCLING AND CONTROL OF METALS
I
I —
Q_
LU
Q
0
1
2
3
4
5
6
7
8
9
10
20
30
40
50
1965-
A
_Q
Q.
a
ao
n
Q
1970
1959
"O
a:
O
1885-
AMBROSIA HORIZON
•1830-
300 400 500 600 700 800 900 1000 1100 1200 1300 1400
TOTAL MERCURY IN ppb
Figure 1. The vertical distribution of total observed
mercury in core E30, expressed in ppb.
Reproduced by permission of the Nail. Res. Counci] of Canada
from the Canadian Jour, of Earth Set., 9, 636-651 (1972).
-------
TRACE METALS - NATURAL SOURCES
REFERENCES
1. Parker, R. L.,Data of Geochemistry, Composition of
the earth's crust, U. S. Geol. Survey Prof. Paper
440-D, D1-D19, 1967.
2. Wedepohl, K. H., Composition and abundance of
common igneous rocks, Handbook of
Geochemistry, 1, 227—249, Springer Verlag,
Berlin, and New York, 1969.
3. Tourtelot, H. A., Chemical compositions of rock
types as factors in our environment, Geol. Soc.
Am. Mem. 123,13-30,1971.
4. Hopps, H. C. and H. L. Cannon, editors, Symposium
on geochemical environment in relation to health
and disease, Ann. N. Y. Acad. Sci. 199, 1-352,
1972.
5. Rankama, Kalervo, and Sahama, Th. G.,
Geochemistry, Univ. Chicago Press, 1—912,
1950.
6. Goldberg, E. D., Minor elements in sea water,
Chemical Oceanography, Vol. 1, J. P. Riley and
G. Skirrow, editors, Academic Press, London and
New York, 163-196, 1965.
7. Wedepohl, K. H., Composition and abundance of
common sedimentary rocks, Handbook of
Geochemistry, 1, 250-271, Springer Verlag,
Berlin, and New York, 1969.
8. Saxby, J. D., Metal-organic chemistry of the
geochemical cycle, Rev. Pure Appl. Chem, 19,
131-150, 1969.
9. Gulbrandsen, R. A., Chemical composition of
phosphorites of the Phosphoria Formation,
Geochim. et Cosmochim. Acta., 30, 769-778,
1966.
10. Bertine, K. K. and E. D. Goldberg, Fossil fuel
combustion and the major sedimentary cycle,
Science 173,233-235,1971.
11. Vine, J. D. and E. B. Tourtelot, Geochemistry of
black shale deposits — a summary report, Econ.
Geol. 65,253-272, 1970.
12. National Academy of Sciences, Committee on
Biologic Effects of Atmospheric Pollutants,
Lead, Airborne lead in perspective, 330, 1972.
13. Durum, W. H., J. D. Hem, and S. G. Heidel,
Reconnaissance of selected minor elements in
surface waters of the United States, Oct.1970, U.
S. Geol. Survey Circ. 643, 1-49,1971.
14. Wakita, H. and R. A. Schmitt, Cadmium: Handbook
of Geochemistry, K. H. Wedepohl, ed., Vol. 11/2,
23, Springer Verlag, Berlin, and New York,
1970.
15. Hem, J. D., Chemistry and occurrence of cadmium
and zinc in surface and ground waters, Water
Resources Research 8, 661-679,1972.
16. Mink, L. L., R. E. Williams, and A. T. Wallace, Effect
of industrial and domestic effluents on the water
quality of the Coeur d'Alene River basin, Idaho
Bur. Mines Geol. Pamphlet 149, 1-95,1971.
17. Onishi, H., Arsenic, Handbook of Geochemistry, K.
H. Wedepohl, ed., Vol. II-l, 38 pp. Springer
Verlag, Berlin, and N. Y., 1969.
18. Tourtelot, H. A., Minor-element composition and
organic carbon content of marine and nonmarine
shales of Late Cretaceous age in the western
interior of the United States, Geochim. et
Cosmochim. Acta. 28, 1579-1604,1964.
19. Tourtelot, H. A., L. G. Schultz, and J. R. Gill,
Stratigraphic variation and chemical composition
of the Pierre shale in South Dakota and adjacent
parts of North Dakota, Nebraska, Wyoming, and
Montana, U. S. Geol. Survey Prof. Paper 400-B,
B447-B452, 1960.
20. Ruch, R. R., E. J. Kennedy, and N. F. Slump,
Studies of Lake Michigan bottom sediments, IV;
Distribution of arsenic in unconsolidated
sediments from Lake Michigan, 111, Geol.
Survey Environmental Geol. Notes (37) 1—16,
1970.
21. Angino, E. E., L. M. Magnuson, T. C. Waugh, 0. K.
Galle, J. Bredfeldt, Arsenic in detergents:
Possible danger and pollution hazard, Science
168,389-390,1970.
22. Borgono, J. M. and R. Greiber, Epidemiological
study of arsenicism in the city of Antofogasta,
Proc. Univ. Missouri 5th Ann. Conf. Trace
Substances in Environmental Health, 13—14,
publ. 1972,1971.
23. U. S. Geol. Survey, Mercury in the environment, U.
S. Geol. Survey Prof. Paper 713,1-67,1970.
24. Jonasson, I. R., Mercury in the natural environment:
a review of recent work, Canada Geol. Survey
Paper 70-57,1-39,1970.
25. Jonasson, 1. R. and R. W. Boyle, Geochemistry ot
mercury and origins of natural contamination of
the environment, Can. Mining Met. Bull 65
(717), 32 39,1972.
26. Cameron, E. M. and I. R. Jonasson, Mercury in
Precambrian shales of the Canadian Shield,
Geochim. et Cosmochim. Acta. 36, 985—1006,
1972.
27. Thomas, R. L., The distribution of mercury in the
sediments of Lake Ontario, Can. Jour. Earth Sci.
9,636-651,1972.
28. Kennedy, E. J., R. R. Ruch, and N. F. Shimp,
Distribution of mercury in unconsolidated
sediem from southern Lake Michigan, 111. Geol.
Survey Environmental Geol., Notes (44) 1—18
1971.
29. Burton, J. D. and T. M. Leatherland, Mercury in a
coastal marine environment, Nature 231,
440-441, 1971.
30. Aston, S. R., D. Bruty, R. Chester, and J. P. Riley,
Distribution of mercury in North Atlantic
deep-sea sediments, Nature, Phys. Sci., 237, (77)
125,1972.
-------
10
CYCLING AND CONTROLS OF METALS
31. Cronan, D. S., The Mid-Atlantic Ridge near 45° N.
XVII, Al, As, Hg, and Mn in ferruginous
sediments from the Median Valley, Can. Jour.
Earth Sci. 9,319-323,1972.
32. Collinson, Charles and N. F. Shimp, Trace elements
in bottom sediments from Upper Peoria Lake,
middle Illinois River, HI. Geol. Survey
Environmental Geology Notes 56, 1—21, 1972.
33. Cranston, R. E. and D. E. Buckley, Mercury
pathways in a river and estuary, Environment
Sci. Technol. 6, 274-278, 1972.
34. Vernet, J. P. and R. L. Thomas, Levels of mercury in
the sediments of some Swiss lakes including Lake
Geneva and the Rhone River, Eclogae Geol.
Helvetiae 65, 293-306,1972.
35. Vernet, J. P. and R. L. Thomas, The occurrence and
distribution of mercury in the sediments of the
Petit Lac (western Lake Geneva), Eclogae Geol.
Helvetiae 65, 307-316, 1972.
36. Gavis, J. and J. F. Ferguson, The cycling of mercury
through the environment, Water Research 6,
989-1008,1972.
37. Joensuu, O. I., Fossil fuels as a source of mercury
pollution, Science 172, 1027-1028, 1971.
38. O'Gorman, J. V., N. H. Suhr, and P. L. Walker, Jr.,
The determination of mercury in some American
coals, Appl. Spectroscopy 26, 44-48, 1972.
39. Schlesinger, M. D. and H. Schultz, An evaluation of
methods for detecting mercury in some U. S.
coals, U. S. Bur. Mines Rept. Invest, no. 7609,
1-11,1972.
40. Swanson, V. E. and J. D. Vine, Composition of coal,
S. W. United States, Geol. Soc. Ann. Program
Ann. Meeting, 683-684 (abs.), 1972.
41. Jenne, E. A., Mercury in waters of the United States,
U. S. Geol. Survey Open-File Rept., 1—34, April
1,1972.
42. Eshleman, A., S. M. Siegel, and B. Z. Siegel, Is
mercury from Hawaiian volcanoes a natural
source of pollution? Nature, 233 (5320)
471-472,1971.
-------
THE LEAD INDUSTRY AS A SOURCE OF
TRACE METALS IN THE ENVIRONMENT
B. G. WIXSON, E. BOLTER, N. L. GALE, J. C. JENNETT AND K. PURUSHOTHAMAN
The University of Missouri—Rolla
Rolla, Missouri
INTRODUCTION
During the past five years the world's most modern
lead industry has developed in a remote Ozark's section
of Southeastern Missouri. The economical impact of
this vast mineral resource is just starting to be known
and promises to offset predictions that sufficient mineral
reserves still must be discovered in order to meet lead
demands during the balance of this century (1). The
third annual report of the council on environmental
quality (2) emphasized that the low-cost lead producers
in Missouri would be able to maintain peak production
and be able to absorb pollution control costs while
high-cost lead producers in other states may be unable to
raise the required capital for pollution control and be
forced to close.
In 1970 the Viburnum Trend or New Lead Belt
ranked first in the world by producing 432,576 tons of
lead ore (3), and in 1971 continued to pace the United
States in lead production (4). Present production trends
for the period January through July 1972 indicate that
289,073 tons of lead have been recovered, which is
46,000 tons above the same period in 1971 (5). This
rapid industrial development in a sparsely populated
rural forest region has resulted in the release of lead,
copper, zinc, cadmium, and other trace metals into a
formerly unaffected ecosystem. Due to this abrupt
change, the mining district has become a unique area for
studying the impact of trace metals and developing
techniques to control detrimental effects. Pollution
abatement studies have been conducted since 1967 and
during the past 18 months an interdisciplinary team,
supported by the National Science Foundation RANN
Lead Study Program with the assistance of local citizens,
the mining industry, concerned local, state, and Federal
agencies, have conducted an extensive investigation on
the environmental effects of this industrial development.
A complete report of this investigation has been
published as an interim progress report to National
Science Foundation (6).
Research has been carried out to determine
background values, to establish natural baselines (7, 8)
and to evaluate the lead industry as a source of trace
metals in the environment. The unusual topography and
drainage pattern of the mining area assisted, since it was
possible to study control sites on streams in the same
area that were not affected by industrial development.
By further use of selected sites below individual
mine-mill operations, wastewater effects on receiving
streams could be studied. The location of the New
Lead Belt, the unique stream drainage pattern, mines
and mills, settling lagoons, a lead smelter, and stream
sampling sites are shown in Figure 1.
Sources of trace metals in the environment were
associated with: symbol A, the mining and milling
operations with problems of grinding, concentrating and
transporting ores, and disposal of tails along with mine
and mill wastewater; and symbol B, the smelter-refinery
process with problems of concentrate haulage, storage,
sintering, refining, atmospheric discharges, and blowing
dust. The systematic exchange and transport from these
operations are illustrated in Figure 2 which depicts the
possible sources of trace metals in the environment of
the New Lead Belt of Southeastern Missouri.
MINING AND MILLING SOURCES
Efficient and modern engineering designs have been
incorporated into the mines and mills within the New
Lead Belt. Galena (lead) is the principal ore mined with
lesser quantities of sphalerite (zinc), chalcopyrite
(copper), and silver recovered as economic co-products.
Geologically the lead ore is disseminated throughout the
Cambrian Bonneterre Formation, mostly a dolomite, at
depths ranging from 700 to 1,200 feet. Since the
producing formation also serves as a good aquifer, most
mines must employ constant pumping, ranging from
3,000 to 7,000 gpm, in order to prevent flooding. This
inflow of water has reduced mine dust as a potential
problem source but the mine water pumped to the
11
-------
CYCLING AND CONTROL OF METALS
MINE
MINE UNDER
CONSTRUCTION
SETTLING POND
SCALE
SMELTER
SAMPLING
SITES
CONTROL
SAMPLING
MILES 6 SITES
MISSOURI
NEW LEAD
BELT|
I
N
TO
CLEARWATER
RESERVOIR
I
Figure 1. The New Lead Belt of southern Missouri.
-------
TRACE METALS - LEAD INDUSTRY
13
LEAD ZINC
COPPER CADMIUM
ORE
LEAD, ZINC,
AND
COPPER
CONCENTRATE
MILLING AND
CONCENTRATION
TRANSPORT
BY
RUNOFF
SEDIMENTS
LEAD CONC. BY
ROAD OR RAIL
TO SMELTER
OR STORAGE
SMELTING
PROCESS
VEGETATION
TRANSPORT
BY ROAD OR RAIL
TO OTHER
SMELTERS AND
OTHER ECOSYSTEMS
ZINC, COPPER
AND CADMIUM
MATTE
FINISHED
METAL
PRODUCTS
Figure 2. Sources of trace metals in the environment of
the New Lead Belt of Southeastern Missouri.
-------
14
CYCLING AND CONTROL OF METALS
surface does contain an appreciable amount of fine
galena and associated trace metals as well as associated
spillage from equipment operations and maintenance.
Generally mines in the new mining district are worked
by a standard room-and-pillar method. The back ore is
drilled and shot in one or two passes followed by
haulage to a gyratory crusher via large diesel loaders or
locomotive-drawn rail cars. After primary crushing
underground, the ore is hoisted to the surface in a skip.
Most of the mines also employ two shafts, one for men
and equipment and one for ore hoisting and charging of
the ore bin at the mill. Since automation is a key factor,
the best known equipment and technology is employed
at the mines.
Part of the water pumped from the mines is utilized as
a process water, for the milling procedure, where
chemical reagents are added during the flotation circuit
to separate the lead, zinc or copper minerals from the
finely ground rock or gangue. The flotation reagents
usually consist of chemical collectors, frothers,
depressants, and activants.
The lead and zinc, and sometimes copper, minerals
from the flotation process are pumped into thickeners,
where the concentrate settles leaving the water, excess
flotation reagents, colloidal, and supracolloidal minerals
to be discharged as a milling effluent. The concentrate is
vacuum dried by various methods and then transported
to smelters for the final conversion of metal. A typical
mine and mill production flow chart is illustrated in
Figure 3.
The water and tailing wastes from the mine and mill
operations are discharged into settlement and treatment
£ TIRE-MOUNTED ax*:*:
:;;;S;:JUMBO-DRILL : PRIMARY
PRODUCTION
HAULAGE
•.•.•.•.•.-.•.•.•.•... .^. t. q aom
E *:EVEL:| £^£*?riT?O ^* Q ^8
SECONDARY
PRIMARY CRUSHER
SCREEN
SKIPS
TO SURFACE
SKIP
LOADER
FINE
LEAD
FLOTATION
MILL CYCLONES ORE BINS SAMPLE
TERTIARY
rCRUSHER
SECONDARY
SCREENING
,u
Pb FLOTATION
ROUGHER CONCENTRATE
THICKENER FILTER I HOPPER CAR
SMELTER
-CLEANER
Zn FLOTATION
ROUGHER
CONCENTRATE
THICKENER FILTER HOPPER CAR
ZINC SMELTER
->- TA ILING POND
Figure 3. Mine-mill production flow chart. [Courtesy of Amax Lead Co. of Mo.]
-------
TRACE METALS - LEAD INDUSTRY
15
lagoons. The tailing pond dams are usually constructed
from the tails, generally less than 200 mesh in size, of
the ore concentration process which are separated into
fine and coarse fractions by cyclones, centrifugal
separators. Once the dams have been initially
constructed, the tailings and other liquid wastes are
introduced upsteam until the lagoon is effectively filled.
The lagoons are supposed to settle out residual tails and
biologically degrade any spent organic reagents
discharged from the milling process.
In order to evaluate the effects of the developing lead
mines on water quality and aquatic ecosystems, an
extensive sampling program was established. Twenty-one
principal sampling sites were selected. Samples were
bi-monthly and analyzed for both heavy metals and
organic parameters of pollution.
Quantitative determinations of the dissolved and
suspended metallic content of the water, algae, stream
sediments, and aquatic biological specimens were
determined using atomic absorption techniques. Basic
water quality measurements, other than metals, were
performed (9).
Visual observations were made of the general stream
conditions, amount of flow, dominant plant life, and
apparent animal life. Preliminary studies were conducted
to ascertain heavy metals concentrations in algal mats
and other aquatic vegetation at selected areas both
upstream and downstream from selected sites where
contamination was indicated.
Heavy metal concentrations in the streams, before the
start of the mining activity and in the control streams
following the start of the activity, were found to be in
the range of 1 to 20 parts per billion (ppb) for copper,
lead, and zinc. Most of the values were in the 4 to 6 ppb
range and the water pH ranged from 7.0 to 8.8 (10).
Other geochemical background values were 1.5 to 27
ppm for calcium, 0.8 to 5 ppm for sodium, 0.5 to 0.9
ppm for potassium, and up to 30 ppb for manganese.
The results of lead analyses on selected stream sites,
over a one year period, showed 22 separate unfiltered
samples which were in excess of the 0.05 ppm limit set
for drinking water by the U. S. Public Health Service
(11). Six of these samples, of which the highest
contained 0.83 lead, occurred on the same day,
December 15, 1971. These high values were invariably
concomitant with storm runoff, and the stream flow
during the storm of December 15 was of sufficient
quantity and turbulence to achieve complete scouring of
the bottom with virtually complete removal of the
biological slime layer on all affected streams.
There were some 42 episodes noted where the zinc
concentrations were above the 0.1 ppm established as
the maximum allowable concentration in the Effluent
Guidelines proposed by the Missouri Clean Water
Commission. The highest value (0.237 ppm) was
observed on December 15, concomitant with heavy
runoff. Results therefore indicate that problems with
zinc in effluents occur in two mining and milling
effluent discharges.
There were 11 episodes of copper concentrations in
excess of the 0.02 ppm guidelines set by the Missouri
Clean Water Commission and the U. S. Public Health
Service standards for fish toxicity.
Further investigations indicated that the heavy metal
content of mine and mill discharge waters, in the New
Lead Belt of Southeastern Missouri, could be sufficiently
reduced in retention lagoons to permit discharge into
streams (7). Under existing geochemical conditions,
slightly basic pH and elevated bicarbonate content,
excess heavy metals are probably precipitated as
carbonates.
Samples of algal mats, biological slimes, and aquatic
vegetation were collected for analysis of heavy metals
contamination and found that heavy metals
concentrations were highest, approximately 8000 ppm
on a dry weight basis, near the tailings dams of muling
operations (12). The dense and tangled communities of
algae and associated microconsumers were found to act
as excellent filters in addition to their nutrient trapping
and recycling abilities. The finely ground particles of
rock flour or minerals, that escaped the flotation process
and tailings reservoirs, are efficiently trapped and
removed by the benthic flora. Figure 4 illustrates the
accumulation of trace metals in algae on streams
receiving mine and mill effluent.
74,100
4000
3000
r
-------
16
CYCLING AND CONTROL OF METALS
Regardless of the aquatic plant species tested, the
concentration of heavy metals was most prolific on
those samples collected near the source of heavy metals
at the tailings ponds. The exact nature of the association
of the heavy metals with the algae or other plant life
remains to be established. Additional work has been
carried out on some stream consumer organisms such as
tadpoles, crayfish, snails, minnows, and larger fishes, but
evaluations are incomplete at this time.
Using these data and input from the many other
research areas involved in this study, a number of
recommendations have been made or implemented by
the mining companies, including:
A. Dust containing heavy metals from the tailings dams
is suspect as a source of stream pollution and these
dams should be covered with soil and planted with
grass to prevent future problems.
B. The lagoons used to treat the milling wastes have
been redesigned to prevent short circuiting, thereby
allowing better sedimentation and biodegradation of
the organic reagents used. Where economically
possible, total recirculation of the mill water has
been advised. Figure 5 illustrates the modified
mining and milling lagoon waste treatment scheme
now employed at one mine as opposed to their prior
normal mining and milling wastewater ponding
scheme (13).
GRINDING MILL
LEAD-ZINC
ORE
FROM"
MINE
FLOTATION
REAGENTS
ADDED
WATER
PUMPED
FROM -
MINE
'CONCENTRATE
THICKENERS
EXCESS
FLOTATION
CELLS EFFLUENT
DISCHARGE
OR RECYCLE
TAILINGS
SETTLING AND
TREATMENT
LAGOONS
5/DISCHARGE
1 I TO
i J RECEIVING
STREAMS
WATER
.CYCLONED
Figure 5a. Flow diagram of mining and milling wastes.
GRINDING MILL
LEAD-ZINC
ORE
FROM MINE
FLOTATION
REAGENTS
ADDED
WATER
PUMPED
FROM
MINE
CONCENTRATE
THICKENERS
SETTLING AND TREATMENT LAGOONS
MINE WATER ONLY
WATEJ*
T-JOINT .
BAFFLE_/
DI S~C H A R G E
EFFLUENT
DISCHARGE
TREATMENT AND
RECYCLING LAGOON
FOR TAILINGS
AND MILL PROCESS
WASTEWATER
RECYCLED
WATER
TAILINGS FROM
MILLING AND
FLOTATION PROCESS
CYCLONED
Figure 5b. Modified flow diagram for treatment
recycling of mining and milling wastes.
DISCHARGE
TO
RECEIVING
STREAMS
and
-------
TRACE METALS - LEAD INDUSTRY
17
TRANSPORTATION SOURCES
The effects of railroad and truck transportation of
lead, zinc, and copper concentrate has also been studied.
The railroad, which dissects the smelter area in a
north-south direction, is used for transporting supplies
to the industries and for carrying out finished lead metal
or ore concentrates in gondola cars which are open at
the top. The influence of this ore concentrate haulage by
truck and railroad has been evaluated and elevated levels
of trace metals have been found at distances of up to
100 feet from the road (6). Hants used in this study
were tall fescue, a domesticated forage grass, purple top,
a native grass species, and blueberry. Values of 4000
ug/g (dry weight) were found for purple top at roadsides
along ore haulage routes, as compared with 49 ug/g (dry
weight) found along nonhaulage control routes.
Concurrent work was carried out on soil samples taken
from traverses at right angles to haulage routes (6). Data
also indicated that the transport of ore concentrate in
open trucks or railroad cars, without coverage,
contributes windblown trace metals into the
environment. Additional research work is being
continued to evaluate amounts and rates of materials
and possible control measures.
SMELTER AREA SOURCES
The industrial operations in the smelter area involve
smelting sinter in the blast furnace to produce finished
lead. The metallic impurities associated with the
production of lead are copper, silver,zinc, and cadmium.
The air pollution problems created by smelting the
sulfide-containing concentrates include sulfur dioxide
derived from sinter machines; as well as dusts, and fumes
containing lead and other heavy metals from the
sintering operation.
The smelter complex converts galena ore to usable
metal. Lead concentrates, containing 65 to 75 percent
lead and 14 to 17 percent sulfur, are brought to the
plant by rail and trucks. Concentrates are mixed with
fluxing materials, such as silica and limestone, along with
granulated slag and delivered to the sintering plant,
where the mixture is roasted, to burn off the sulfur, and
converted to a porous material called sinter. The
resulting sinter is combined with coke and charged into
the top of a blast furnace. The charge is ignited in a high
oxygen environment, melted, and reacted to form
molten lead and slag. Lead and slag flow from the
furnace into a brick-lined settler. Slag overflows the
settler into a granulation pit, where it is transferred to
storage. Lead bullion is tapped into pots and transferred
to dressing kettles where it is refined and cast into either
100 Ib pigs or 1-ton ingots. A typical general flow sheet
of lead smelting is shown in Figure 6.
During normal production 450 tons of concentrates
are charged to the furnaces per day; the smelter under
WIND
BLOWN
DUST
FLUXES
LEAD
CONCENTRATES
DUST
SINTER CHARGE
PREPARATION
SINTERING
COARSESINTER
FURNACE
CHARGE
PREPARATION
LEAD
BLAST
FURNACEl
MAIN
STACK
ACID
PLANT
STACK
CLEANED GAS
TO ATMOSPHERE
SILVER-LEAD-*—JREFINERY
D I I I I I /•% Kl T /"\ 1 1
BULLION TO
MARKET
r
GRANULATED!
SLAG
REFINED LEAD
TO MARKET
f
FUMES
DUSTCLEANED
GAS TO
ATMOSPHERE
SLAG
TO
DUMP
SS
GS
LS
SILICA SAND
GRANULATED SLAG
LIMESTONE
Figure 6. General flow sheet of lead smelting.
-------
18
CYCLING AND CONTROL OF METALS
these conditions emits 30 to 75 tons sulfur dioxide
through a 200-ft stack when sinter plant, sulfuric acid
recovery plant, and blast furnace are operating. This
particular lead industry has annually contributed
approximately 11,000 to 27,400 tons of sulfur dioxide
and about 100 to 200 tons of particulate matter
depending upon the operation condition of the plant.
Research studies have been conducted with three
sulfur dioxide monitoring stations, 10 dustfall stations
and two meteorological stations. Sulfur dioxide was
continuously monitored. Settleable particulates were
collected once a month, and wind direction and speed
were monitored continuously.
The settleable particulate samples were analyzed for
four metals, cadmium, copper, lead, and zinc by the
atomic absorption technique and the results were
reported as grams per square meter per month
(g/m2-month).
The maximum values of deposition rates of particulate
lead have occurred at sampling stations which were
located near the railroad, even though the most frequent
wind direction was not always toward these stations
(14). This indicates the influence of the open railroad
cars and the prevailing winds around the vicinity of the
stations. The annual average of settleable particulate lead,
for the ten sampling sites, is illustrated in Figure 7.
The particulate lead was found to be as high as 20.5
g/m2 per month at station 7 with an annual average of
8.6 g/m2 per month. Normally, three locations (stations
3, 6, and 7) within a distance of 1000 ft from the stack
showed high deposition rates as compared to other
stations. This indicated that the metallic particulates do
not travel far from the source; hence more studies need
to be conducted on the size distribution, physical
properties, and chemical characteristics of the heavy
metal-laden particulates. The annual average deposition
rates of particulate zinc, copper, and cadmium have been
found to be in the decreasing order of 0.53, 0.18, and
0.064 g/m2 per month, respectively, following the
particulate lead.
The deposition rate of particulate lead, zinc, copper,
and cadmium decreases with increasing distance from
the stack. At this time, information on the radial
distribution of metallic particulates settling upon the
ground is not known, but will be obtained to estimate
the heavy metal accumulation patterns.
Further studies are being conducted to determine the
heavy metal concentration in airborne suspended
particulates and to develop a model for the short and
long-range atmospheric transport of metallic particulates
discharged from the lead smelting operations.
COOPERATION AND SOCIETAL RELEVANCE
This research was initiated when industry and the
public began to wonder if an industry could operate in a
sensitive ecosystem without damaging a national park.
The study has received the complete cooperation of
10)0-87
0-43(^9) BUICK TOWER
Figure 7. Settleable particulate lead—annual average
(g/m2-mo).
concerned industries, the general public, and every local,
Federal and State agency interested in the problem.
Research findings have been applied by industries to
control specific problem areas uncovered during this
study. This unique cooperation has become a model for
environmental cooperation and has been observed and
cited as being of benefit to the local community and its
surrounding (15).
The value of this cooperation was recently emphasized
(16). This spirit of working together must be continued
if needed mineral resources are to be developed without
damage to the surrounding environment.
ACKNOWLEDGMENTS
The authors would like to acknowledge that this
project was supported by the RANN (Research Applied
to National Needs) Lead Study Program of the National
Science Foundation. The AMAX Lead Company of
Missouri and the St. Joe Mineral Corporation are due
thanks for their continued support of research, technical
assistance, and help. Sincere appreciation is also due to
-------
TRACE METALS - LEAD INDUSTRY
19
the Clark National Forest, the Missouri Clean Water
Commission, the Missouri Air Conservation Commission,
the Missouri Department of Conservation, the U. S.
Bureau of Mines, and representatives from Region VII,
EPA, Kansas City, Missouri, for their assistance and
cooperation in this study.
REFERENCES CITED
1. Lead-Airborne Lead in Perspective. National
Academy of Sciences, Committee on Biologic
Effects of Atmospheric Pollutants, Washington,
D.C.,2,1972.
2. Environmental Quality - The Third Annual Report
of the Council on Environmental Quality.
Council on Environmental Quality, Washington,
D.C., 297,1972.
3. The World's No. 1 Lead Producer. Missouri
Geological Survey and Water Resources, Rolla,
Missouri Mineral News, 11, No. 3, March 1971.
4. Lead in 1971. Mineral Industries Surveys, U. S.
Dept. of Interior, Bureau of Mines, Washington,
D. C.,Jan. 1972.
5. Lead Industry in July 1972. Mineral Industries
Surveys, U. S. Dept. of Interior, Bureau of
Mines, Washington, D. C., Sept. 1972.
6. An Interdisciplinary Investigation of Environmental
Pollution by Lead and Other Heavy Metals from
Industrial Development in the New Lead Belt of
Southeastern Missouri, submitted by the
Interdisciplinary Lead Belt Team, University of
Missouri—Rolla, to the National Science
Foundation RANN program, Vol. I & II, June 1,
1972.
7. Wixson, B. G., E. A. Bolter, N. H. Tibbs, and A. R.
Handler, Pollution From Mines in the 'New Lead
Belt' of Southeastern Missouri. Proc. 24th Ind.
Waste Conf., Purdue Univ., Ext. Ser. 135, 632,
1969.
8. Wixson, B. G., Water Quality Protection in Streams
in Mining Districts, in Developments in Water
Quality Research, H. I. Shuval (Ed.), Ann
Arbor-Humphrey Science Publishers, Ann Arbor,
Mich., and London, Eng., 199,1970.
9. Standard Methods for the Examination of Water and
Wastewater, 13th Ed., American Public Health
Assoc., 1015 18th Street, N. W., Washington, D.
C., 1971.
10. Bolter, E. and N. H. Tibbs, Water Geochemistry of
Mining and Milling Retention Ponds in the 'New
Lead Belt' of Southeastern Missouri. Completion
Report to OWRR, Project NO. A-032-MO, 34
pages, 1971.
11. Jennett, J. C., B. G. Wixson, E. Bolter, and J. O.
Pierce, Environmental Problems and Solutions
Associated With the Development of the World's
Largest Lead Mining District. Presented at the
Society of Engineering Science First
International Meeting on Pollution: Engineering
and Scientific Solutions, Tel Aviv, Israel and
published in the proceedings, June 1972.
12. Gale, N. H., M. G. Hardie, J. C. Jennett, and A.
Aleti, Transport of Trace Pollutants in Lead
Mining Wastewaters. Presented at the Sixth
Annual Conference on Trace Substances in
Environmental Health, Univ. of Mo.—Columbia
and published in the proceedings, June 1972.
13. Jennett, J. C. and B. G. Wixson, Problems in Lead
Mining Waste Control. Jour. Water Poll. Control
Fed., 44,2103,1972.
14. Purushothaman, K., Air Quality Studies of a
Developing Lead Smelting Industry. Presented at
the Society of Engineering Science First
International Meeting on Pollution: Engineering
and Scientific Solutions, Tel Aviv, Israel and
published in the proceedings, June 1972.
15. Zuckerman, S., et al., Report of the Commission on
Mining and the Environment. London, England,
Sept. 1972.
16. AMAX in Perspective. E/MJ Engineering and Mining
Jour., McGraw-Hill Pub., New York, N. Y., Sept.
1972.
-------
SOURCES OF TRACE METALS FROM
HIGHLY-URBANIZED SOUTHERN CALIFORNIA
TO THE ADJACENT MARINE ECOSYSTEM
D. R. YOUNG, C-S.YOUNG, AND G. E. HLAVKA
Southern California Coastal Water Research Project
Los Angeles, California
INTRODUCTION
The southern California coastal basin sustains one of
the most rapidly growing urban complexes in the United
States. Stretching more than 400 kilometers from Point
Conception to the U.S.—Mexico border over an area of
about 30,000 sq km (Figure 1), this basin is occupied by
approximately 11,000,000 persons, or about five
percent of the nation's population. Most of its
population growth has occurred in Los Angeles and
Orange Counties, in a pattern that now is being repeated
in Ventura County to the north and San Diego county
to the south.
35
121°W 120°W 119°W 118°W
117°W
116°W
115° W
114° W
34°N
33°N
32°N
31°N -
CALIFORNIA
=«=VENTURA
CONCEPTION
IP 6 M^ 1 ^ AtNcGoE L«E V
HYPERIONJ ORANGE
.P.^TH
O.C.S.D.
PT. LOMA
ENSENADA
BAJA \
CALIFORNIA
E3COASTAL PLAIN
—DRAINAGE DIVIDE
KILOMETERS
I i
Figure 1. The coastal plain of southern California and the adjacent marine waters of the Southern
California Bight.
21
-------
CYCLING AND CONTROL OF METALS
The bordering Southern California Bight is bounded
on the west by the California current. This current
moves southward along the California coast past Point
Conception, and turns landward several hundred
kilometers to the south, impinging upon the coast in the
vicinity of Cabo Colnett, Baja California, Mexico and
forming the southern boundary of the Bight. Part of the
current then turns north, joining a complicated
circulatory pattern of the waters off southern California,
while the remaining flow continues south (1).
The increasing urban, suburban, and industrial
development has resulted in significant pollution
problems in the coastal basin. Thus, the local
municipalities and industries have turned to the
Southern California Bight for disposal of liquid, and
some solid, waste materials. The high mountain ranges,
that run parallel to the coastline approximately 100km
inland, effectively trap air pollutants generated within
the coastal basin, and facilitate transport of aerial
contaminants, by fallout and rainout, and terrestrial
contaminants, by surface runoff, to the Bight.
The adjacent marine ecosystem of the Bight is a major
recipient of the wastes produced in the highly urbanized
coastal basin. In this paper we will discuss the present
state of knowledge of the trace metal inputs to the
Bight. We will describe the nature of the various trace
metal sources, estimate the magnitudes of potential
sources and compare the significance of the inputs. The
sources to be discussed include municipal wastewater
discharges, discrete industrial and thermal discharges,
surface runoff, vessel protective measures, ocean
dumping, aerial inputs, and California current advective
transport.
Figure 2 shows the locations of marine outfalls for
municipal wastewaters (W), discrete industrial discharges
(I), and cooling waters from power plants (P) in the
Southern California Bight. Figure 2 also shows the major
surface drainage channels along the southern California
coast. Of these discrete sources, municipal wastewaters
have received the most attention in the past.
MUNICIPAL WASTEWATERS
At present approximately 1,000,000,000 gallons
(1000 mgd) of treated municipal wastewaters are
discharged daily through marine outfalls to the Southern
California Bight. Most of this, 84 percent, receives
primary treatment only. Three major municipal
wastewater discharges to the Bight occur within about
30 km of Palos Verdes Peninsula (Figures 1 and 2).
Located off this peninsula is the Joint Water Pollution
POINT
CONCEPTION
W9
P10
SANTA
MONICA
POINT DUME
BAY'",,,.
0^ UJ ^
^> <*\ ',-z-
•* ""'l '\^
^ Al \ ^
0\!o-- •.'i
A ^ LONG \*
J).;/VP2BEACH'^
°X.P4*» l28
DANA
POINT
W20
«: —
O a
1/1 ^*'
*s£(*^/
.. T.J, .W 2 2
PI1
W17 W18 W19 SAN MS
CLEMENTE
<*••
V
• THERMAL POWER PLANT
^INDUSTRIAL WASTE DISCHARGER
OMUNICIPAL DISCHARGER 0.
10
20
L_
30
40
L_
50
—i
KILOMETERS
Figure 2. Locations of discrete discharges (municipal wastewater, industrial and thermal discharges,
and surface runoff) to the Southern California Bight.
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
23
Control Plant (JWPCP) outfall system (average length:
1.5 miles) of Los Angeles County Sanitation Districts,
the largest of the municipal wastewater discharges in the
Bight (370 mgd). To the northwest in Santa Monica Bay
lie the 5 mile effluent and 7 mile digested sludge outfalls
(335 and 5 mgd, respectively) of the Hyperion Sewage
Treatment Plant of the City of Los Angeles; to the
southeast lie the old 1 mile and new 5 mile outfalls of
Orange County Sanitation Districts (130 mgd). The City
of San Diego (90 mgd) discharges through the Point
Loma outfall (2 miles); the City of Oxnard (12 mgd)
discharges approximately one mile off the Ventura
County coast. Altogether these five major dischargers
contribute approximately 95 percent of the municipal
wastewaters discharged into the Southern California
Bight. These discharges occur at depths of 50 to 100
meters, generally below the thermocline.
Trace metal monitoring programs by the major
dischargers were established prior to, or during, 1971.
This has enabled us to complete a reliable estimate of
trace metal mass emission rates from municipal
wastewater discharges to the Bight for 1971. Table 1
shows the 1971 average concentrations of ten trace
metals: silver, cadmium, chromium, copper, mercury,
nickel, lead, zinc, iron, and manganese as reported by
the major discharges.* It is to be noted that a variety of
collecting, compositing, and analytical procedures were
employed in the dischargers' routine monitoring
*The 1971 average concentrations of total suspended solids
(mg/1) in the final effluents of these wastewater dischargers
are: Oxnard — 80; Hyperion effluent — 73; Hyperion sludge —
3,000; JWPCP - 330; Terminal Island - 120; O.C.S.D. - 145-
Pt. Loma - 110.
programs. Figure 3 shows, as an example, the monthly
variation of zinc concentrations in wastewater discharge.
These time variations are typical of those for the other
metals studied, and illustrate that, while individual
monthly values can vary from the year-long mean by a
factor of two or occassionally three, order-of-magnitude
deviations are uncommon.
In order to evaluate the intercomparability of these
concentration values reported by the various
laboratories, we conducted a short term trace metal
survey in the summer of 1971. With the assistance of
plant personnel, week-long composite samples at each of
the five major treatment plants were collected. Grab
samples were collected by the regular procedures at one
or two hour intervals for seven consecutive days. Every
day these samples were filtered by 0.45-micron filters,
and the residues and filtrates were frozen along with the
unfiltered replicates. At the end of the collection period
the water samples were thawed and combined into
weekly composites which were immediately refrozen.
The filtrate composites and daily residues were analyzed
by atomic absorption spectrometry at the University of
California, San Diego.f Unfiltered composites were
submitted to the treatment plant laboratories for trace
metal determination.
The results of this survey indicated generally good
agreement between those metal concentrations reported
by the treatment plant laboratories and the University of
fThis study was conducted in collaboration with J. Galloway,
University of California, San Diego.
TABLE 1 AVERAGE CONCENTRATIONS OF TRACE METALS (mg/8) IN FINAL
EFFLUENTS OF MUNICIPAL WASTEWATER DISCHARGERS, 1971
Discharger mgd Silver
Chro-
Copper Mercury Nickel Lead Zinc Iron
Manga-
nese
Remarks
(note exceptions
in footnotes)
W9 Oxnard
W10 Hyperion
12
x
0.02
0.00
0.06
0.02
0.09 <.001
0.01
0.06
0.01
<.06
0.28 0.50
0.08 0.18
0.12
0.01
Avg. of Jan'71 &
Mar '72 values
Effluent
Sludge
Wll JWPCP
W12 Terminal
Island
W16 Orange
Co. San. Dist.
W24 Pt. Loma
335
X
5
X
371
X
8
X
130
X
90
X
sx
0.002f 0.05
0.001 0.02
0.03 f 0.23
0.003 0.05
0.02 0.03
0.03 0.002
0.002/ 0.01
0.00 0.01
0.02 0.06
0.01 0.01
0.02
0.01
0.006
0.002
0.03
0.005
—
<.006
.006
-
—
*A11 cobalt concentrations are averages of 24-hr composite s;
-{•Hyperion effluent and sludge silver concentrations are aven
0.29
0.07
2.1
1.3
0.86
0.03
0.11
0.01
0.22
0.06
0.15
0.04
0.23 0.003
0.03 0.001
12 0.10
1.6 0.01
0.56 0.001
0.03 0.0001
0.26 0.001
0.12 0.001
0.35 0.001 #
0.003
0.16 <.001
0.03
imples collected 24 Aug. and 9 Sept.
iges of 4 monthly values; effluent mi
0.28
0.04
2.6
0.33
0.24
0.01
0.42
0.16
0.16
0.03
0.06
0.01
70.
inganese
0.06
0.02
0.51
0.15
0.25*
0.04
0.00
0.00
0.22
0.06
0.10
0.01
0.46
0.07
16
2.1
2.4
0.11
0.36
0.14
0.54
0.12
0.18
0.02
0.73
0.09
47
8.8
9.9
0.63
0.94
0.04
1.2
0.33
—
concentration is average of 1 1
O.Olf
0.01
1.6
0.78
0.13
0.01
0.05
0.05
0.09
0.03
^
monthly values.
Avg. of 12 monthly
values
Avg. of 1 2 monthly
values
Avg. of 12 monthly
values
Avg. of Jan. & July
values
Avg. of Oct.-Dec.
values
Avg. of July— Sept.
values
lead concentration is average of 10 monthly values.
/Terminal Island silver concentration is average of Aug. and Sept. 71 values.
$Drange Co. mercury concentration is estimated from analysis of 22 grab samples, 15-21 J un 72.
-------
24
CYCLING AND CONTROL OF METALS
Zn
3.0 -
O
5. 2.0
Z
LU
D
1.0
\/
\/*?»';D--...'...,...--•"
30
O
s
O
20 Q
Z>
Z
O
10
a.
>-
X
J FMAMJ JASOND
1971
Figure 3. Concentrations of zinc observed during 1971
in municipal wastewaters of the major treat-
ment plants along the southern California
coast. Solid circles indicate concentrations
measured in one-week composites of these
wastewaters (2).
California, San Diego (2). The ratios of the two reported
values usually were within a factor of two, and no trends
were apparent. For those concentrations not reported by
the treatment plants, comparisons between Galloway's
data and the regular monitoring data for the closest
collection period usually still showed a ratio of three or
less. Figure 3 illustrates such comparisons for zinc.
Table 2 presents the percentages of trace metals that
were found to be associated with the residue portions of
the effluent samples. Although particles of smaller than
0.45-microns may be retained by the filter, the results
do indicate a high degree of association between most of
the metals and the wastewater solids. For silver,
cadmium, chromium, copper, lead, zinc, and iron, 84 to
94 percent of the metals were associated with the
residue. For cobalt, nickel, and manganese, these values
range from 42 to 54 percent.
Although the data listed in Table 1 indicate
considerable differences in average metal concentrations
between the various wastewaters, the concentrations
found on the wastewater particulates agreed much more
closely, as is seen in Table 3. For example, the average
1971 metal concentrations (mg/1) in Hyperion effluent
were generally 5 to 50 times lower than those in the
digested sludge; however, on a particulate basis (mg/dry
kg), the effluent concentrations in the composited
effluent residue were generally only two to three times
lower than those in the sludge residue. It is apparent that
particulates play an important role in the wastewater
transport of trace metals.
TABLE 2 PERCENT OF TRACE METAL RETAINED BY 0.45-MICRON
FILTERS IN ONE-WEEK COMPOSITES OF FINAL EFFLUENT
FROM MUNICIPAL WASTEWATER DISCHARGERS, SUMMER,
1971 (After Reference 2)
Discharger
(data sampled)
W9 Oxnard
(8/15-8/21)
W10 Hyperion
Effluent
(7/26-8/1)
Wll JWPCP*
(8/13-8/19)
W16 Orange County
(8/27-9/2)
W24 Point Loma
(8/1 --8/7)
X
Silver
87
75
95
97
85
88
Cad-
mium
92
88
95
98
91
93
Cobalt
50
50
72
42
54
Chro-
mium
90
64
95
81
90
84
Copper
91
86
96
94
90
91
Nickel
80
35
45
57
74
58
Lead
92
90
97
97
92
94
Zinc
94
86
91
94
94
92
Iron
90
80
91
93
91
89
Manga-
nese
40
34
60
44
30
42
thit -,™, m , i on?' r ••""" •«• ' "i "rum monuormg oata ot Los Angeles county Sanitation Distri
that approximately 90^ of the total mercury in JWPCP final effluent was retained on a 0.8-micron filter
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
25
TABLE 3 TRACE METAL CONCENTRATIONS (mg/dry kg) IN WASTEWATER PARTICULATES* AND
NATURAL MARINE SEDIMENTS OFF SOUTHERN CALIFORNIA (After Reference 2)
W9 Oxnard
W10 Hyperion
Effluent
Sludge
Wl 1 JWPCP
Wl 6 Orange County
W24 Point Loma
Natural Nearshore
Marine Sediment
Silver
30
130
265
32
40
105
1.0
Cad-
mium
115
108
180
65
245
65
0.4
Cobalt
15
4
23
8
-
8
7.2
Chro-
mium
350
1440
3430
1700
1330
1000
46
Copper
1000
1500
2500
1120
1850
1600
16
Nickel
145
520
670
220
220
310
14
Lead
300
320
1000
570
920
545
8.5
Zinc
1500
2300
4820
4100
2330
3000
63
Iron
9000
5400
13000
20000
7000
10000
25000
Manga-
nese
140
108
156
150
120
200
320
*Residue after filtration through 0.45-micron Millipore filter.
Table 4 presents the estimated annual trace metal mass
emission rates from municipal wastewater discharges to
the Southern California Bight.* This estimate indicates
that approximately 95 percent of the trace metals
carried by municipal wastewaters into the Southern
California Bight are discharged from a coastline
approximately 70 km in length. From a broad-scale
point of view, the trace metal inputs from municipal
wastewater to the Bight may be considered as a
semi-point source centered around the Palos Verdes
Peninsula.
DISCRETE INDUSTRIAL DISCHARGES
In contrast to the case for municipal wastewaters,
where a few major discharges contribute most of the
waste input, the situation for discrete industrial
discharges is much more complex. The types of
industrial processes and reclamation steps, if any,
employed can play a vital role in the total quantity of a
particular trace metal that is released in the discharge,
irregardless of the volumetric flow rates. The first step in
evaluating the importance of this source of trace metals
to the Bight was to categorize the discharges in terms of
the type of waste generated, the flow rate, and the
location of the discharge. These data were obtained from
the files of the local Regional Water Quality Control
Boards, the state regulatory agencies for waste discharge
into the waters of southern California.
Tabulations of such data for thermal cooling water
and petroleum-related discharges along the coast are
presented in Tables 5 and 6. No significant data on the
concentration of trace metals in these discharges were
located during the inventory compilation.!
One of the highly industrialized regions of the coast is
the San Pedro Bay area. This is the site of Los
Angeles-Long Beach Harbor, and is located just to the
southeast of Palos Verdes Peninsula. In addition to the
*The corresponding input rate for total suspended solids is
estimated to be 278,000 M tons/yr.
fAn extensive analysis of the nature of thermal discharges to
the Bight already has been presented elsewhere (3).
TABLE 4 TRACE METALS MASS EMISSION RATES (M tons/yr) FROM MUNICIPAL WASTEWATER
DISCHARGERS TO THE SOUTHERN CALIFORNIA BIGHT, 1971
Discharger
W9 Oxnard
W10 Hyperion
Effluent
Sludge
Wll JWPCP
Wl 2 Terminal
Island
Wl 6 Orange Co.
W24 Point Loma
TOTAL
Flow
(mgd)
12
335
5
371
8
130
90
950
Silver
-
0.9
0.2
10
-
3.6
-
15
Cad-
mium
0.3
23
2
15
0.1
11
2.5
54
_ Chro-
Cobalt mium
1
2.8 130
0.2 10
440
1
40
19
3.0 640
Copper
1
110
80
290
3
63
20
570
Mer-
cury
-
1.4
0.7
0.5
-
0.2
0.1
2.9
Nickel
1
130
18
120
5
29
8
310
Lead
-
28
4
130
-
40
12
210
Zinc
4
210
110
1220
4
97
22
1700
Iron
8
340
320
5100
11
220
-
6000
Manga-
nese
2
5
11
67
1
16
-
100
-------
26
CYCLING AND CONTROL OF METALS
TABLE 5 ANNUAL DISCHARGE OF COOLING WATER
FROM THE MAJOR POWER GENERATING
STATIONS ON THE SOUTHERN CALIFORNIA
COAST
Generating
station
Flow
(108 cu m/yr)
FOSSIL-FUEL
L. A. Dept. of Water and Power
PI Harbor — Wilmington
P2 Haynes — Seal Beach
P3 Scattergood - Playa del Key
Subtotal
Southern California Edison Co.
P4 Alamitos - Seal Beach
P5 El Segundo — El Segundo
P6 Huntington — Huntingdon Beach
P7 Long Beach — Long Beach
P8 Mandalay — Oxnard
P9 Redondo - Redondo Beach
PI 0 Ormond — Ormond Beach
Subtotal
San Diego Gas and Electric Co.
PI 1 Encino - Carlsbad
PI 2 Silver Gate - San Diego Bay
PI 3 South Bay - San Diego Bay
PI 4 Station "B" - San Diego Bay
Subtotal
NUCLEAR
PI 5 San Onofre - San Clemente
TOTAL
1.1
10.5
2.5
14.1
11.6
5.0
6.5
0.8
3.2
9.8
10.2
47.1
2.2
2.2
5.0
0.9
10.3
5.5
77.0
extensive recreational, commercial and naval vessel
activities there, San Pedro Bay receives more than 150
discrete industrial waste discharges, either directly into
the bay or via storm drains (see Table 7). The combined
flow rate of these discharges, excluding cooling waters
from power plants, is about 100 mgd, or about 10
percent that of the combined municipal wastewater
discharges to the Bight. Approximately 10,000 metric
tons per year of suspended solids are carried into the
bay; this is about 3 percent of the total figure for the
combined municipal wastewaters. As for the coastal
industrial discharges, no significant data on trace metal
concentrations in industrial discharges to the bay were
located. As is seen in the table, the combined flow rate
for metallic industrial discharge (3.8 mgd) constitutes
only about 4 percent of the total industrial discharge to
the bay. However, the significance of this low percentage
should not be over emphasized. The lack of any
significant trace metal data in the public files for the
industrial discharges described above represents a serious
gap in the knowledge of trace metal inputs to the
Southern California Bight.
SURFACE RUNOFF
There are 200 to 300 surface runoff discharge
locations along the southern California coast. However,
approximately 70 percent of the average annual flow is
carried by 15 major streams during the storm runoff
season. The normal annual precipitation in the southern
California coastal basin averages approximately 40 cm
(15 in.), and surface runoff from about 60 percent of
the drainage area is regulated by dams and other flood
control measures. The southern California coastal
streams generally carry appreciable flow only during and
shortly following the occasional rainstorms.
In an attempt to characterize the surface runoff in the
southern California basin, five major watersheds were
selected for study during the storm season of 1971 to
72. These were the Santa Clara River, Ballona Creek, the
Los Angeles, Santa Ana, and San Luis Rey Rivers
(Figure 2).
In light of the apparent association of trace
constituents with particulates, a survey was made on the
relationship between flow rate and concentration of
suspended sediment in southern California storm runoff.
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
27
TABLE 6 DISCRETE INDUSTRIAL WASTE DISCHARGERS OF THE SOUTHERN
CALIFORNIA COAST
11
12
13
14
15
16
17
18
19
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
Discharger
Phillips Petroleum - Point
Conception
Texaco, Inc. — San Augustin
Getty Oil - Gaviota
Shell Oil - El Capitan
Signal Oil & Gas - EUwood
Atlantic Richfield - Coal
Oil Point
Standard Oil — Summerland
Standard Oil — Carpinteria
Atlantic Richfield — Rincon
Atlantic Richfield — Rincon
Island
Western Oil & Dev. - Rincon
Petrol Industries — Rincon
Continental Oil — Rincon
Norris Oil Co. — Rincon
Phillips Petroleum — La Conchita
Phillips Petroleum — Punta Garda
Mobil Oil - Sea Cliff
Continental Oil - Pitas Point
Continental Oil — Grubb Lease
Getty Oil - Ventura
Standard Oil - McGrath Beach
McDonnell Douglas Corp. -
Venice
Standard Oil - El Segundo
Standard Oil - Island Esther
Union Oil — Platform Eva
Signal Oil and Gas - Platform
Emmy
Signal Oil and Gas - Huntington
Beach
Standard Oil - Huntington
Beach
Gulf Oil - Huntington Beach
Type of waste
Oil brine
Tanker ballast
Oil brine
Oil brine
Tanker ballast
Oil brine
Tanker ballast
Oil brine
Tanker ballast
Oil brine
Oil brine
Oil brine
Tanker ballast
Oil brine
Oil brine
Oil brine
Oil brine
Oil brine
Oil brine
Oil brine
Oil brine
Oil brine
Tanker ballast
Oil brine
Oil brine
Oil brine
Tanker ballast
Oil brine
Cooling tower
bleedoff
Cooling water
Refinery wastes
Oil brine
Oil brine
Oil brine
Oil brine
Oil brine
Oil line ballast
Flow
(mgd)
0.2
0.2
0.16
0.2
0.29
0.06
0.4
0.4
0.01
0.04
0.36
0.01
0.49
0.05
0.36
0.4
0.18
0.27
0.75
0.06
0.14
0.65
72
1
0.02
0.08
0.6
0.8
0.01
-------
28
CYCLING AND CONTROL OF METALS
TABLE 7 COMBINED FLOW RATES (mgd) OF DISCRETE INDUSTRIAL WASTE DISCHARGERS
IN THE SAN PEDRO BAY AREA
Discharge area
L. A. Harbor
Long Beach Harbor
Dominguez Channel
L. A. River Tidal Prism
Los Cerritos Channel
San Gabriel River
Tidal Prism
TOTAL
Oil field
brine
0.43
24
0.05
5.9
3.4
34
Oil line
and tanker
ballast
0.82
5.7
-
-
-
—
6.5
Refinery
& petro-
chemical
28
-
6.5
1.1
-
—
36
Metallic
2.0
0.03
1.4
-
0.12
0.19
3.8
Fish
cannery
9.6
-
-
—
-
-
9.6
Miscel-
laneous
chemical
5.6
3.8
2.3
-
0.04
—
12
Total
47
34
10
7
0.2
3.6
102
Data were provided by the United States Geological
Survey from studies conducted during January and
February, 1969. Typical examples of the relationship
that was found for this abnormally wet year are
illustrated for the Santa Clara River and the Santa Ana
River in Figures 4 and 5, respectively.
It is seen that, over the four day periods, peaks in the
concentration of suspended sediment clearly correlate
with peaks in the flow rate. The peak amplitudes often
are roughly proportional; this relationship, where
9 140,000 -
applicable, has significant implications for programs
aimed at the determination of mass emission rates of
particulate-associated materials. For when the
concentration (Q) is proportional to the flow rate (Fj),
e.g. Q = kFj, the transport rate (T) of the suspended
substance increases as the square of the flow rate:
T =
= kSFj2
i= 1
(1)
z
o
OL
h—
Z
UJ
U
Z
o
120,000 -
100,000 -
80,000 -
O
OL
SANTA CLARA RIVER
SUSPENDED SEDIMENT (MG/L)
60,00t> -
40,000 -
20,000 -
10,000
0000 0800 1600 0000 0800 1600 0000 0800 1600 0000 0800 1600
24-1-69 25-1-69 26-1-69 27-1-69
Figure 4 Comparison of discharge rate and suspended sediment concentration as a function of time
in Santa Clara River storm runoff during January 24 to 27, 1969.
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
29
140,000
^ 120,000
O
s
z
O
CL
\—
Z
100,000
80,000
2 60,000
O
40,000
20,000
e B
SUSPENDED SEDIMENT (MG/L)-— ^M SANTA ANA RIVER
A
•
3
i •
H
*
1 :
• •
- ||
/x
•
. X
/x*
*
A'X
•i i
r x:
k'x'U
•: 1 x.
DISCHARGE (CFS)
*/
i''-
1 -
\ A'x
H /V
*.
'A
\
\i" // \
t :
. 1 x
i \i
\:
' V. /•
^ • "x -o< ~
'xc>\\ */"\
• \H f ^
v-<:i
tv. //
'x.xx
iii i i i i i i
20,000
18,000
16,000
14,000
12,000
10,000
8000
6000
4000
2000
2
u
«
SCHARI
Q
1200 2000 0400 1200 2000 0400 1200 2000 0400 1200 2000
23-2-69
24-2-69
25-2-69
26-2-69
Figure 5. Comparison of discharge rate and suspended sediment concentration as a function of time
in Santa Ana River storm runoff during February 23 to 26, 1969.
Under such conditions most of the transport of
particulate-borne substances occurs during the period of
peak flow. Sampling frequency therefore should be
greater at these times to more accurately determine the
total transport of the suspended material.
In order that representative samples of the storm
runoff and its suspended sediments would be collected, a
special depth-integrating sampler was constructed. This
sampler was patterned after the United States Geological
Survey suspended sediment pint sampler, but was
enlarged to a one gallon capacity to provide sufficient
sample for trace-level analyses. Other modifications also
were made to decrease the chance of contamination;
these will be reported in detail later. The collection
stations were over the centers of the channels at bridges
that were located as near to the coast as possible but
above the tidal prism. As soon as possible after
collection, generally within a few hours, the samples
were taken to our laboratory where they were filtered
through 0.45 micron filters. The filtrates and residues
then were frozen until analyzed.
In this program, nine time series were obtained
covering up to three storms in four channels. During
periods of peak flow samples were collected at
approximately two-hour intervals. The 1971 to 1972
period was an unusually dry year; all the channels did
not flow at each storm, and no significant flow occurred
in the San Luis Rey River and the southern streams
during the year. Thus, the total surface runoff, estimated
The corresponding input of suspended sediment (silt) to the Bight
to be 242 x 106 cu m, including both storm and dry
weather flow, was approximately 43 percent of the long
term average for the Bight. Of the 167 x 106 cu m of
storm flow to the Bight, during the year, approximately
60 percent was covered in this sampling program.
Analyses of these samples were conducted at the
California Institute of Technology (4). Concentrations
of ten trace metals, the same as for municipal
wastewaters, were measured in the runoff filtrates and
residues. Where necessary, concentration of the samples
with ion exchange resin was employed, followed by
measurement using atomic absorption spectroscopy. A
detailed analysis of the data, including a comparison of
individual metal inputs from the various basin types, is
still underway, and, along with a description of
analytical procedures will be reported later (4).
An example of the results for the total concentrations
of silver, copper, and lead in storm runoff from Los
Angeles River is presented in Figure 6, along with the
flow rate and concentration of suspended sediment.
These data illustrate the general correlation of peak
values for flow rate, and silt and metal concentrations
that was observed during this study. Calculations of mass
emission rates for the ten metals studied were made
from such concentration and flow rate data. Table 8 lists
the estimates obtained to date for metal inputs to the
Bight from runoff during water year 1971 to 72.* Also
listed are the average values for percent of trace metal
associated with particulates in the runoff samples. In
is estimated to be 274,000 M tons/yr.
-------
30
CYCLING AND CONTROL OF METALS
100,000
10,000
o
1,000
100
LOS ANGELES RIVER
\
\
\
\
•\\
\\
-
x\
1000
00
o
o
u
z
o
10
0400
0800
1200
1600
2000
0000
0400
0800
1200
22-12-71
23-12-71
Figure 6. Concentrations of three trace metals and suspended sediment (silt) in the discharge (flow)
of Los Angeles River during December 22 to 23, 1971.
general, these input rates were considerably lower than
those for municipal wastewaters during 1971. For
example, surface runoff inputs during the year
constituted the following percentages of the 1972
municipal wastewater inputs of metals to the Bight:
silver, 6.7 percent; cadmium, 1.9 percent; chromium, 3.8
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
31
TABLE 8 ESTIMATED TRACE METAL MASS
EMISSION RATES (M tons/yr) FROM
SURFACE RUNOFF TO THE
SOUTHERN CALIFORNIA BIGHT,
1971-72
Metal
Silver
Cadmium
Cobalt
Chromium
Copper
Mercury
Nickel
Lead
Zinc
Iron
Manganese
Mass emission
rate
1.1
1.2
5.3
25
18
0.06
17
90
100
26000
180
%
particulate*
74
78
75
82
59
63
89
74
99
72
*Percent of metal retained by 0.45-micron filter.
percent; copper, 3.2 percent; mercury, 3.3 percent;
nickel, 5.5 percent; zinc, 5.9 percent. Only for lead (43
percent), cobalt (170 percent), iron (430 percent), and
manganese (180 percent) were the runoff inputs
relatively important.
DIFFUSE SOURCES
In addition to the discrete or point sources of
pollutants which have been discussed previously, there
are a number of potentially significant pollutants whose
sources to the Bight are distributed widely and thus are
much more difficult to quantitate. Four such pollutant
sources are vessel antifouling paint and fuel
comsumption, ocean dumping, airborne inputs, and
advective transport by the California current. Although
these source categories have not been investigated
thoroughly, preliminary analyses were conducted to
provide a rough estimate of possible importance of these
sources and to assist in establishing priorities for future
studies. The following data on inputs from diffuse
sources are order-of-magnitude estimates only and are
presented here primarily to provide guidance for future
studies.
VESSEL BODY PROTECTIVE MEASURES AND
FUEL COMSUMPTION
The Southern California Bight harbors a large number
of recreational, commercial, and naval vessels. Losses of
bottom antifouling paint and anticorrosive anodes and
spent fuel residues may represent important sources of
trace pollutants to the marine environment.
To investigate the magnitude of these potential
sources of pollutants, a preliminary survey of
recreational vessel activity was undertaken. The two
major objectives of this investigation were to inventory
the recreational craft in each of the fourteen major
marinas between Santa Barbara and San Diego, and to
obtain preliminary information on the consumption, and
presumed release to the Bight, of certain materials such
as antifouling paint, sacrificial zinc anodes, and leaded
fuel in one of the largest recreational vessel facilities,
Marina del Rey in Los Angeles. Estimates of the
quantities of trace metals used in bottom paints and in
spent fuel in Marina del Rey could be extrapolated to
estimate annual marina-related input of these metals to
the Bight.
Antifouling Paints and Primers
The largest drydock in Marina del Rey, Windward
Yacht and Repair, was studied to obtain an estimate of
the use of antifouling paints. Of the 5,500 recreation
craft in the marina^ nearly 1,200 are hauled out and
painted annually. Fifty to 60 gallons of antifouling paint
are applied weekly; the old paint is removed and washed
through a storm drain into the marina. Thus, this
drydock uses approximately 2,860 gallons of antifouling
paint annually, which corresponds to about 2.4 gallons
per boat. Based on this analysis, it is estimated that
approximately 13,000 gallons of antifouling paint are
applied annually to the recreational craft moored in
Marina del Rey. Assuming that vessel activity in the
marina is typical of recreation craft in the marinas of the
Bight, and extrapolating this unit paint consumption, it
is estimated that the annual antifouling paint require-
ment for the 34,850 recreation craft in the Bight
area is approximately 84,000 gallons. A gallon of
antifouling paint weighs about 8.6 kg, which results in
an estimated total annual paint usage rate of
approximately 720,000 kg for recreational craft.
In a recent study conducted by San Diego Regional
Water Quality Control Board (5) Barry estimated that
the annual paint usage for commercial and naval vessels
at the major shipbuilding and repair facilities in San
Diego Bay was approximately 30,000 gallons of
antifouling paint (8.6 kg/gal), 23,000 gallons of red lead
primer (5.2 kg/gal), and 10,000 gallons of zinc chromate
primer (4.1 kg/gal). It is estimated that, at the most, 10
percent of the paints or coatings removed by sand
blasting of commercial and naval vessels is lost to the bay
water. The bulk of the sand and coating residues is
disposed of in land fills.
Comparable information for other major harbor
facilities, such as the Los Angeles-Long Beach Harbor, is
not yet available. If one assumes that San Diego Bay
practices are representative of commercial and naval
vessels generally, then the annual loss of antifouling
paints and primers to the Bight is estimated to be as
follows: Antifouling paint, 52,000 kg; red lead primer,
24,000 kg; zinc primer, 8,200 kg.
Estimation of the concentrations of trace constituents
in antifouling paints and primers is difficult; however,
the results from the Marina del Rey survey indicate that
antifouling paints typically contain between 35 to 78
-------
32
CYCLING AND CONTROL OF METALS
TABLE 9 ESTIMATED TRACE METAL COMPOSITION OF
ANTIFOULING PAINT AND PRIMERS
Type
Antifouling paint
Zinc chromate primer
Read lead primer
Trace
metal
Copper
Mercury
Arsenic
Zinc
Chromium
Lead
Average concentration
(%)
50
0.5*
0.2f
45
12
25
*Assuming that mercury content of mercury paints is 5% and that
mercury paints comprise 10%of total paint usage.
t Assuming that arsenic content of arsenic paints is 2% and that
arsenic paints comprise 10% of total paint usage.
percent cuprous oxide (31 to 69 percent as copper).
Although the use of mercury compounds in marine paint
was banned recently by the U. S. Environmental
Protection Agency, some paints containing about 7
percent mercury phenate and 3 percent yellow oxide of
mercury and unspecified concentrations of arsenic are
still being sold.
Based on Barry's report, it is estimated that
antifouling paints contain, by weight, up to 67 percent
cuprous oxide, 3.4 percent mercury phenate, 1.3
percent mercury oxide, and 1.7 percent phenarsazine
chloride (zinc compound). In addition, primers,
apparently used mostly on the larger commercial and
naval vessels, may contain up to 45 percent zinc, 12
percent chromium (as zinc chromate), and 25 percent
lead (red lead primer).
From the limited information available, estimates have
been made of the average trace metal concentrations of
antifouling paints and primers (Table 9). Using the
foregoing estimated concentrations of trace metals, the
annual input of such materials from these sources has
been estimated and are reported in Table 10.
Zinc Anodes
The use of sacrificial anodes to control galvanic
corrosion provides another source of trace metals to the
Bight. Investigations at Marina del Rey indicate that
about 90 percent of the sail and power craft harbored
there employ zinc anodes to control galvanic corrosion.
It is estimated that each boat uses approximately 4 to 5
kg of zinc per year for this purpose. Thus, it is estimated
that about 160 metric tons of zinc per year are
contributed to the Bight from the use of zinc anodes,
most of which go into the marina harborage areas.
Data furnished by Bunker Hill, Inc., a major supplier
of anode material, indicate that zinc anodes also contain
approximately 0.05 percent cadmium, implying that
approximately 0.1 metric tons per year of cadmium
enter the Bight from this source.
It should be noted that the foregoing estimates do not
consider the sacrificial anode contribution from
commercial and naval vessels because of the lack of
specific information on this source. Hence the estimates
appear to be quite conservative.
TABLE 10 ESTIMATED TRACE METAL MASS EMISSION RATES (M tons/yr) FROM RECREATIONAL,
COMMERCIAL AND NAVAL VESSELS TO THE SOUTHERN CALIFORNIA BIGHT*
Cadmium Chromium Copper Mercury Lead Zinc
Source
Gross
tonnage
Recreational vessels
Antifouling paint
Zinc anode
Fuel
720
160
1.4
0.1
360 3.6
160
3.5
Commercial and naval
Vesselsf
Antifouling paint
Zinc chromate primer
Red lead primer
TOTAL
52
8.2
24
0.1
— —
1.5 0.1
26
1 _
1 390
0.3
3.9
6
9.5
4.1
160
tNo estimates for gross tonnage of zinc anodes and fuel used.
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
33
Leaded Fuel
Union Oil Company, which operates the only fuel
dock at Marina del Rey, reports its annual fuel sales of
about 440,000 gallons of low-lead gasoline (containing
0.5 gm Pb/gallon) and 110,000 gallons of high octane
gasoline (containing 3 gm Pb/gallon). Thus, the
consumption of these fuels results in the release of about
0.55 metric tons of lead per year to the Bight from
Marina del Rey fueled craft. If these fuel consumption
and lead release data are applied to all recreational craft
moored hi the Marinas of the Southern California Bight,
an input of lead to the Bight of approximately 3.5
metric tons per year is obtained.
Trace Material Mass Emission Rates
Table 10 presents a summary of the annual mass
emission rates for trace metals reaching the Bight from
selected sources associated with recreational,
commercial, and naval vessel activity. It is recognized
that some of the estimated inputs are crude; however,
they represent the best information available. Moreover,
it should be noted that the estimated vessel related
mercury input of 4 metric tons per year is greater than
the total input of mercury from treated municipal
wastewater and surface runoff. The estimated vessel
related input of copper (390 M tons/yr) is about
two-thirds of the corresponding copper input to the
Bight from municipal wastewater runoff.
OCEAN DUMPING
In an investigation of past ocean dumping practices,
data on eight major types of wastes dumped from vessels
into the Bight was reviewed. These were: (a) refinery
wastes, (b) chemical wastes, (c) filter cake, (d) oil
drilling wastes, (e) refuse and garbage, (f) radioactive
wastes, (g) military explosives, and (h) miscellaneous
types of wastes.
Figure 7 shows the location within the Southern
California Bight of both active and inactive ocean
dumping sites. Fourteen ocean dumping sites, which were
approved either by the U. S. Army Corps of Engineers or
by the California Regional Water Quality Control
Boards, have been designated for waste dumping
purposes since 1931. At present, dumping of various
types of wastes at nine designated sites is prohibited by
regulatory agencies, and disposal of military explosives
at two other sites is still under moratorium issued by the
Department of Navy in 1971.
Table 11 lists the major dumping sites, the total
tonnage dumped during various periods, and the
estimated present annual dumping rate for each type of
waste.
Refinery Wastes
It is estimated that approximately 480,000 metric
tons of petroleum refining wastes were dumped between
1946 and 1971, corresponding to an annual average of
PT.
CONCEPTION
OIL DRILLING WASTES
EXPLOSIVES
FILTER CAKE
INDUSTRIAL
RADIOACTIVE (CHEMICALS) —
NORTH CHANNEL ISLANDS
VESSEL REFUSE AND GARBAGE
ACTIVE SITE
INACTIVE SITE
PROPOSED SITE
E ' SANTA
CATALIN A I. ( V
SAN CLEMENTE I.
32° -
121°
120° 119° 118° 117°
Figure 7. Locations of ocean dumping sites in the Southern California Bight.
116"
-------
34
CYCLING AND CONTROL OF METALS
TABLE 11 SUMMARY OF WASTES DUMPED INTO THE SOUTHERN
CALIFORNIA BIGHT, 1931-71
Type of
waste
Refinery wastes
Chemical wastes
Filter cake
Oil drilling wastes
Refuse and garbage
Radioactive wastes
Military explosives
Miscellaneous wastes
Record
period
1946-71
1965-71
1947-71
1960-67
1969-70
1966-70
1931-71
1944^70
1947-68
1946-68
1945-70
Estimated total
during record
period
(M tons)
480,000
2,800
5,700
140
320,000
3,000,000
47,000
7,400
90,000
-
-
Estimated
present
tonnage*
(M tons/yr)
1,800
470
210
-
-
1,200
-
-
250
*Wastes for which no present tonnage estimate is given have been discontinued
(military explosives by moratorium).
about 18,000 metric tons per year. However, the
reported annual dumping rate has dropped to about
1,800 tons per year since 1968. The principal dumping
site for refinery waste is in the San Pedro Channel. The
specific composition of these refinery wastes are
unavailable; however, they are believed to include spent
caustic solutions, acid sludges, spent catalysts,
petrochemical wastes, and chemical cleaning wastes.
These materials surely must include trace metals, trace
organics, and other potentially toxic substances, but
quantitative information is not available.
Chemical Wastes
This type of industrial waste is dumped either in
sealed containers or in bulk by tank barge, and includes
waste material from aerospace, heat-treating, plating,
film processing, chemical processing, and electronic
manufacturing firms, industrial, medical, and academic
laboratories, and military and other sources. Most of the
recorded bulk tonnage, 210 metric tons/yr since 1947, is
discharged approximately 15 km east of Catalina Island.
Most of the containerized chemical wastes, 470 metric
tons/yr since 1965. have been dumped in San Pedro
Channel. Between 1960 and 1967, approximately 140
metric tons of chemical waste, sodium cyanide, were
dumped in bulk 32 km west of Point Loma, However.
such dumping there has been prohibited since 1967.
Filter Cake and Oil Drilling Wastes
Two types of relatively inert material, filter cake, 70
percent fixed and 50 percent volatile solids, and oil
drilling wastes, similar to dredging spoils, were dumped
to the Bight in large amounts for a short period. Filter
cake, consisting of about 50 percent perlite and 50
percent cellulose, is used in extraction of algin from
kelp, and approximately 320,000 metric tons were
dumped about 15 km west of Point Loma during 1969
and 1970. More than 3 million metric tons of oil drilling
mud and cutting were dumped in the San Pedro Channel
between 1966 and 1970. These two types of dumpings
have been prohibited and discontinued since 1970.
Refuse and Garbage
Until recently, naval vessel refuse and garbage has been
dumped into the Bight. Between 1947 and 1968, an
estimated total of 90,000 metric tons were dumped in
the vicinity of the Coronado Islands, and between 1944
and 1970 an estimated total of 7,400 metric tons were
dumped 40 km southeast of Catalina Island. However,
approximately 1,200 metric tons per year of refuse and
garbage from commercial vessels is still being dumped
approximately 16 km east of Catalina Island.
Other Types of Waste
Between 1945 and 1970, undetermined quantities of
unspecified military explosives and toxic chemical
ammunition have been dumped in several designated
dumping sites in the Bight. Low-level radioactive wastes
also have been dumped in the authorized locations
during the period of 1946 to 1968. Dumping of militaiy
explosives and other wastes has been interrupted by a
moratorium issued by the Navy in 1971. Dumping of
radioactive wastes has been terminated since its
prohibition in 1968.
Based on information furnished by H-10 Water Taxi
Company, Los Angeles, approximately 250 metric tons
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
35
per year of undefined miscellaneous wastes are dumped
in the Southern California Bight.
Trace Constituent Mass Emission Rates
Although there has been an attempt to quantify the
distribution and amount of wastes in selected types
dumped into the Bight, virtually nothing has been found
in the public record regarding the concentration of
specific pollutants in the wastes dumped. Thus, for
pollutants such as trace metals, estimation of mass
emission rates from this source is very difficult.
Nevertheless, order-of-magnitude estimates of the
probable upper limits of such mass emission rates have
been attempted. It appears that only refinery and
chemical wastes and some undefined miscellaneous
wastes currently constitute any significant source of
trace pollutants to the Bight. As shown in Table 11, it is
estimated that approximately 1,800 metric tons per year
of refinery waste and 1,000 metric tons per year of
chemical and miscellaneous wastes were dumped into
the Bight off Los Angeles and San Diego in 1971. It
seems reasonable to assume that, on the average, these
wastes would not contain more than 0.5 to 1 percent, by
weight, of any one of the trace constituents being
investigated by Southern California Coastal Water
Research Project, with the exception of iron and zinc. It
is likely that these wastes might contain up to 2 percent
zinc and 10 percent iron. Owing to the value of mercury
and silver, upper limits for their average concentrations
are assumed to be an order-of-magnitude lower than the
general level taken for most of the other metals. Based
on these extremely rough assumptions, upper limit
estimates of present annual trace metal mass emission
rates are presented in Table 12.
AERIAL FALLOUT
Limited data are available on aerial fallout rates of
trace metals to the Bight. This source is difficult to
quantitate for several reasons, including the high
horizontal velocity compared to the vertical velocity of
airborne particles, the diffuse nature of the source, the
relatively high constituent gradients that may exist near
the densely-populated areas, and the large area of the
Bight.
Rainfall Washout
Several recent studies have provided some insight into
this subject. Estimates of metal contributions from rain
falling directly on the Bight (6), conducted on Catalina
Island from September 1966 to January 1967, are
shown in Table 13. The median metal concentration
values were used, and an average annual rainfall rate of
40 cm (15 in) over a Bight area of 100,000 sq km was
assumed. It should be noted that these data do not
include the contribution of metals to the Bight from dry
fallout.
The results of this rough estimate indicate, as seen in
the summary Table 15, that the mass emission rate of
lead from direct rainfall washout on the Bight is
significantly higher than that from the discrete sources,
municipal wastewater and surface runoff. The mass
emission rates of nickel and iron from direct rainfall
washout, on the contrary, are much lower than those
from the discrete sources to the Bight. For copper,
TABLE 12 UPPER-LIMIT ESTIMATES OF TRACE METAL
MASS EMISSION RATES TO THE SOUTHERN
CALIFORNIA BIGHT FROM OCEAN DUMPING
Metal
Silver
Cadmium
Cobalt
Chromium
Copper
Mercury
Nickel
Lead
Zinc
Iron
Manganese
Assumed
maximum concentration
(% by wt)
0.05
0.5
0.5
1
1
0.05
1
1
2
10
1
Est. max.
mass emission
rate*
(M tons/yr)
1.5
14
14
28
28
1.5
28
28
56
280
28
"Based on estimated 1971 dumping tonnage of 1800 M tons/yr of
refinery wastes and 1000 M tons/yr of chemical and miscellaneous
wastes.
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36
CYCLING AND CONTROL OF METALS
TABLE 13 ESTIMATED TRACE METAL MASS EMISSION
RATES FROM DIRECT RAINFALL ON THE
SOUTHERN CALIFORNIA BIGHT
Metal
Copper
Mercury
Nickel
Lead
Zinc
Iron
Manganese
Median concentration*
in rainwater
(Mg/e)
10
0.2
1
25
55
1
12
Mass
emission rate
(M tons/yr)
400
8
40
1000
2200
40
480
'From Reference 6.
mercury, zinc, and manganese, comparable amounts are
contributed from rainfall washout and discrete sources.
Dry Fallout
It is possible that the contribution of particulate-borne
materials to the Bight via dry fallout may exceed those
due to direct rainfall washout. For example, the fallout
rate of lead on dust particles (24 mg Pb/m2-yr) was
about two to three times as large as that due to rainfall
(10 mg Pb/m2-yr) (7). Isotopic analysis confirmed that
this lead was not of soil origin, but that essentially all of
it originated in the combustion of leaded gasoline.
Extrapolation of the La Jolla fallout rates to the entire
Bight yields annual lead input rates through dry and wet
fallout of approximately 2,400 and 1,000 metric tons,
respectively. It is interesting to note that the latter value
is about the same as that obtained by extrapolating the
Catalina Island rainfall data (6).
In 1968, approximately 23,000 metric tons of lead
were combusted in gasoline in California (7). It is
probable that at least half of this comsumption occurred
in southern California. Thus, approximately 10,000
metric tons of lead are released annually to the
atmosphere in this area. The previous data suggest that
as much as one-third of this amount may fall directly
into the coastal waters, depending upon the degree to
which fallout rates at La Jolla and Catalina Island are
representative of fallout to the entire Bight.
ADVECTIVE TRANSPORT
At the regional scale considered here, a potentially
significant but largely unevaluated source of trace metals
transported into the Southern California Bight is the
California current which carries seawater and associated
constituents into the Bight (Figure 1). The complex flow
pattern keeps the water in the Bight for some time,
during which time various physical, chemical, and
biological processes can occur. These processes may
result in the retention of significant amounts of some
constituents in the Bight. These processes may also
result in the removal of significant amounts of other
constituents from the Bight in the advective flow from
the Bight.
Mass Emission Rates
The surface area of the Bight has been estimated to be
about 1 x 1011 sq m. Assuming the mixed surface layer
depth to be 50 m, the volume of the mixed layer of the
Bight is computed to be 5 x 1012 cu m. It has been
shown that the mean residence time of water in the
mixed layer is on the order of 3 months (1). Thus the
advective flow rate of the California current is estimated
to be approximately 2 x 1013 cu m/yr.
Assuming that the trace metal concentrations reported
for ocean waters are representative of California current
waters, the mass transport rates of trace metals into the
Bight by the California current are estimated to be as
shown in Table 14. Although the role of the California
TABLE 14 ESTIMATED TRACE METAL MASS
TRANSPORT RATES TO THE
SOUTHERN CALIFORNIA BIGHT
BY THE CALIFORNIA CURRENT
Metal
Concentration
Mass transport rate
(M tons/yr)
Silver
Cadmium
Cobalt
Chromium
Copper
Mercury
Nickel
Lead
Zinc
Iron
Manganese
0.3
0.1
0.4
0.2
3
0.03
7
0.3
10
3
2
6,000
2,000
8,000
4,000
60,000
600
140,000
6,000
200,000
60,000
40,000
-------
TRACE METALS - MUNICIPAL/URBAN AREAS
37
current as a source of trace metals to the Bight may be
different from those of other sources, the estimated
mass transport rates of most of the trace metals by
advective transport far outweigh the mass emission rates
from other sources. For example, the mass transport rate
of mercury by the California current is estimated to be
about 600 metric tons per year, which is about 30 times
the amount of mass emission rates of mercury from all
other sources to the Bight (8). However, for chromium,
lead, and iron, the annual advective transport rates
exceed the sum of the other, principally terrestrial
inputs by only a few factors. At least for chromium and
lead, whose terrestrial inputs are believed to be largely
anthropogenic, these inputs appear to be a significant
perturbation to the natural mass balance of metals in the
Bight.
The circulation of marine waters off southern and Baja
California is such that increased levels of trace
constituents in the biota to the west and south of the
densely populated southern California coastline may in
fact be due to sources far to the north. For example,
anomalously high levels of zinc—65 were found in the
coastal mussel, Mytilus califomianus, collected during
1963 to 64 from northern Baja California, where the
California current sweeps eastward and impinges on this
coast (9). The suggestion that this anomalous zinc—65
was being carried by the California current was further
supported by increasing concentration of this radiometal
in samples of the oceanic gooseneck barnacle, Lepas
anatifera, collected toward the west off southern
California. In contrast to zinc—65, the other two
radiometals measured, cobalt—60 and manganese—54,
did not show significant differences between the
nearshore of La Jolla and California current speciments.
The levels of these two nuclides also were approximately
constant in M. californianus from both the southern
California and Baja California stations. This argues
against nuclear fallout as the source of the anomalous
zinc-65, and suggest that the Columbia River effluent,
which carried approximately 55,000 pCi zinc—65 per
month into the water off Washington and Oregon, was
elevating zinc—65 concentrations in the marine biota
1,900 km to the south. Therefore, the dense population
center off San Francisco, and the intense agricultural
activity in the large central valley of California, both
may be important source regions of runoff and airborne
pollutants that are introduced into the California current
north of Point Conception. Any such contaminants from
the north could contribute to elevated levels in the
marine biota to the west and south of southern
California.
There is another important aspect of possible
pollutant transport from the north. As the California
current moves slowly down the coast of California,
certain trace constituents introduced into the surface
layer off Washington, Oregon, or northern California
may be incorporated into the food web. If these
substances are subject to trophic or feeding level
concentration, higher levels might be expected in a
specified organism caught off southern California,
compared to levels observed in the same organism caught
to the north. Ocean current advection from the north
could play an important part in contributing to elevated
levels of certain pollutants in the biota off southern and
Baja California.
SUMMARY
In Table 15 we have summarized our estimates of
trace metal annual mass emission rates to the Bight from
the various sources for which sufficient data are
available. Although the values are not all of comparable
reliability, and several potentially important modes are
not quantified at all, the summary does provide useful
insight into which of the input modes studied are of
TABLE 15 ESTIMATED TRACE METAL MASS EMISSION RATES (M tons/yr) FROM VARIOUS SOURCES
TO THE SOUTHERN CALIFORNIA BIGHT, 1971
Metal
Silver
Cadmium
Cobalt
Chromium
Copper
Mercury
Nickel
Lead
Zinc
Iron
Manganese
1
Municipal
wastewater
15
54
3
640
570
3
310
210
1,700
6,000
100
2
Surface
runoff
1
1
5
25
18
0.1
17
90
100
26,000
180
3
Dkect
rainfall
-
-
—
-
400
8
40
1,000
2,200
40
480
4
Vessel*
coating
-
0.1
—
1
390
4
-
10
160
-
—
5
Ocean dumping
maxima
2
14
14
28
28
2
28
28
56
280
28
6
Sum of col. 1
through 5
18
69
22
690
1,400
17
400
1,300
4,200
32,000
790
7
Advective
transport
6,000
2,000
8,000
4,000
60,000
600
140,000
6,000
200,000
60,000
40,000
'Including vessel antifouling paints, primers, and spent fuel residues.
-------
38
CYCLING AND CONTROL OF METALS
probable importance. For example, of the estimated
input routes of locally derived copper and mercury,
municipal wastewater discharge, vessel antifouling paint,
and direct rainfall al] appear to have about the same
importance. For zinc, municipal wastewater and direct
rainfalJ appear to predominate. In the case of lead, the
surface runoff input is the same order as that of
municipal wastewaters, but these sources probably
contribute an order of magnitude less lead to the waters
of the Bight than does aerial fallout. Cobalt, iron, and
manganese are the only other trace metals studied that
have surface runoff inputs of approximately the same
importance as those of municipal wastewaters, and the
inputs of these metals via both modes may be more
dependent on natural than anthropogenic sources.
However, for silver, cadmium, chromium, and nickel,
present data suggest that municipal wastewater discharge
to the Bight dominate all other locally-derived inputs.
Clearly, more comprehensive and reliable information on
the importance of wet and dry fallout, and of
vessel-protective measures, are needed in the above
comparison. Further, the lack of any reliable estimates
of inputs of trace metals from direct industrial
discharges represents a major deficiency in this mass
balance attempt. Correction of these various deficiencies
probably should assume a higher priority than improving
our knowledge on the inputs from ocean dumping, as
the present best estimates of probable maximum values
suggest that only for cobalt does it appear likely that
ocean dumping could represent the major local source.
With the exception of chromium, lead, and iron, for
each of the trace metals studied the sum, see column 6,
Table 15, of all estimated yearly inputs eminating from
the coastal plain of the Bight is one to two orders of
magnitude below the estimated annual flux of the metal
through the Bight via ocean current advection. Although
this situation may be natural in the case of iron, the fact
that local anthropogenic inputs of the other two metals
are, to the first order comparable to that of gross
advection suggests that chromium and lead transport
from the urban areas may represent a specially
important perturbation of the natual metals budget for
the regional ecosystem. However, it is difficult to draw
any very reliable conclusions from the comparison of
local versus advective inputs until more is known about
the net addition of metals to, or removal from, the Bight
due to bottom sediment interactions and to ocean
circulation. Further, the physical-chemical state of a
metal advected into the Bight may be significantly
different from that injected via a particular local input
mode. In addition to better data on input rates of a
particular trace metal to the Bight, much more needs to
be learned about (a) the nature of the metal being
transported to the local marine waters, (b) the changes
that take place in the metal following introduction to
these waters, and (c) the transport processes and
eventual fate of the metal in the ocean ecosystem.
ACKNOWLEDGMENTS
We wish to thank the personnel of Los Angeles
County Sanitation Districts, Hyperion Sewage
Treatment Plant, Orange County Sanitation Districts,
Point Loma Treatment Plant, and Oxnard Sewage
Treatment Plant for providing us with samples and data.
We also thank the California Regional Water Quality
Control Boards of the Los Angeles, Santa Ana, and San
Diego Regions for assistance in surveying their records.
The cooperation of the Los Angeles County Flood
Control District and the United States Geological Survey
in obtaining runoff samples and data is gratefully
acknowledged. Many metal concentrations in surface
runoff and municipal wastewaters were obtained in
collaboration with Professor James J. Morgan (California
Institute of Technology), Dr. James N. Galloway
(University of California, San Diego), and Joseph
Johnson (Southern California Coastal Water Research
Project). Runoff collections were executed by the firm
of Pomeroy, Johnston, and Bailey. We thank Robert
Brown for his assistance in the ocean dumping survey,
and Chesley Reynolds and Frank Hoffman for their
assistance in the marina investigation. Technical
assistance in data gathering was provided by Tung-Kan
Cheng, Kimm Crawford, Eugene Leong, Carlos
Patrickson, Tom Sarason, Gerald Shiller, Cindy Smith,
and Yuan Yuan Tsai. Robin Simpson and Deirdre Van
Hofwegen provided editorial assistance. Finally, we
thank Professor Erman A. Pearson (University of
California, Berkeley), Professor John D. Isaacs (Scripps
Institution of Oceanography), and Philip Storrs
(Engineering-Science, Inc.) for their contributions to this
manuscript.
REFERENCES
I.Jones, J. H., General circulation and water
characteristics in the Southern California Bight, So.
Calif. Coastal Water Research Project, TR 101,
1971.
2. Galloway, J. N., Man's alteration of the natural
geochemical cycle of selected trace metals, Ph. D.
dissertation, Univ. of Calif., San Diego, 1972.
3. Young, C., Thermal discharges into the coastal waters
of southern California, So. Calif. Coastal Water
Research Project, TR 102,1971.
4. Morgan, J. J., D. R. Young, and J. N. Galloway, Ten
trace metals in surface runoff of southern
California, in preparation.
5. Barry, J. N., Staff report on wastes associated with
shipbuilding and repair facilities in San Diego Bay,
Calif. Reg. Water Qual. Control Bd., San Diego
Region, 1972.
6. Lazrus, A. L., E. Lorange, and J. P. Lodge, Jr., Lead
and other metal ions in United States precipitation,
Environ. Sci. & Tech., 4: 55-58, 1970.
7. Chow, T. J. and J. H. Earl, Lead aerosols in the
atmosphere, increasing concentrations, Science,
169:577-80,1970.
-------
TRACE METALS - MUNICIPAL/URBAN AREAS 39
8. Young, D. R., Mercury in the environment: a as indicators of the variation of manganese-54,
summary of information pertinent to the cobalt-60, and zinc-65 in the marine
distribution of mercury in the Southern California environment. Paper presented at the IAEA
Bight, So. Calif. Coastal Water Research Project, symposium on the Interaction of Radioactive
TR 103,1971. Contaminants with the Constituents of the Marine
Environment, at Seattle, Washington, June 10—14,
9. Young, D. R. and T. R. Folsom, Mussels and barnacles 1972.
-------
LUNCHEON ADDRESS
H. A. Laitinen
University of Illinois
-------
OVERVIEW OF EFFECTS OF TRACE METALS
H. A. LAITINEN
University of Illinois
Urbana, Illinois
We may look on the environmental effects of trace
metals from the very narrow viewpoint of the immediate
effects upon the human population or from the much
broader viewpoint of their effects upon the various
components of the total environment including man. It
is important, I think, to take the broadest viewpoint,
first because man can be indirectly affected by
accumulations of pollutants in any part of his
environment, and second because mankind should have a
concern for other living species as well as for the future
generations of his own species.
Trace metals may be classified as to those essential to
life and those not known to be essential to life processes.
Of those known to be essential for at least some species
of life, we may list iron, copper, zinc, manganese, cobalt,
nickel, molybdenum, and vanadium. Some metals,
formerly thought to act only as poisons, are recognized
to be micronutrients at very low concentrations. Among
these are selenium, chromium, and arsenic (1). Even
cadmium has been listed as a micronutrient, and some
authorities have speculated that ail elements for which
organisms develop a tolerance might be essential for
some function. Lead is an element for which there is no
known beneficial function, but which is so wide-spread
as to be detectable in all plants and animals.
A typical biological response curve would show an
increasingly beneficial effect with increasing
concentration up to a certain optimum level. Beyond
this level, there is a tolerance region which may be either
relatively narrow or broad, beyond which benefits
decrease, injurious effects begin, and finally a lethal dose
is reached. For those elements not known to be
essential, the first region of the response curve is missing,
but there is generally a tolerance region followed by the
toxic and lethal dose regions. In this group of metals, we
can list at least theoretically all metals not included
among the major or minor essential elements. Of greatest
concern, of course, are those known to be toxic at low
or moderate concentrations, for example, cadmium,
mercury, and lead.
Trace metals are introduced into the environment by
several mechanisms. First of all, it is important to
distinguish between natural and man-made distribution,
because the former constitutes a background level
against which man-made pollution can be measured.
Among the natural mechanisms, we should include
weathering and leaching of minerals, with distribution
via natural waters or air borne particulates. Also,
volcanic action and natural gases are known to introduce
substantial quantities of certain metals, notably
mercury, into the environment. Among the man-made
sources we can recognize three important mechanisms.
First, particulate matter enters the atmosphere from
smoke stacks, incinerators, open fires, and automotive
exhausts. The latter source accounts for the introduction
of most of the lead. The second source is in the form of
liquid solutions, either industrial wastes and effluents or
municipal sewage. Trace metals entering sewage tend to
be concentrated in sewage sludge, the disposal of which
may spread the metal through the environment if the
sludge is used for agricultural purposes or landfill. The
third source of trace metals is through chemicals applied
to the soil as pesticides. In a listing (2) of 280 pesticides,
heavy metals were mentioned 141 times in 112 of the
formulations. The listings mentioned mercury 45 times,
copper 28, zinc 24, cadmium 13, manganese 12,
chromium 7, tin 5, nickel 4, iron 3, and lead 1. In 1970,
90,000 tons of fungicides were used in agriculture in the
United States. In that same year, 204,000 pounds of
mercury-containing fungicides were used in the United
States and one million in the world as a whole.
Presumably this usage has been strongly curtailed since
that time.
The main mechanisms of movement of trace metals
are through air borne particulate matter and through the
movement of natural waters. Rainfall and snowfall
represent mechanisms whereby particulate matter is
removed from the atmosphere and into surface waters
either as dissolved or suspended matter or sediments.
Heavy metals tend to be concentrated preferentially in
the suspended matter of water rather than being in true
solution, but both suspended matter and solution
41
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42
CYCLING AND CONTROL OF METALS
present mechanisms of transport. Of the trace metals in
solution, electrochemical methods can distinguish
between labile and bound metal. The distinction is that,
of the total heavy metal contained in solution, only a
portion responds to the electroanalytical method, for
example anodic stripping voltammetry, if the natural
water sample is analyzed as received. On the other hand,
if the sample is acidified, then the electrochemical
method shows the total heavy metal content of the
sample. It is believed that the natural water sample
contains complexing agents which tie up the metal ions,
for example lead or copper ions, in a form to which the
method does not respond. Acidification releases the
metal ions from the bound into the labile form. Further
evidence as to the nature of the binding is revealed by
the technique of gel permeation chromatography (3). If
the natural water sample is percolated through a gel
permeation chromatography column, the various
fractions indicate the presence of traces of organic
matter of relatively high molecular weight, of the order
of 10,000, presumably originating from sources such as
humic acids.
Exactly what the significance of such binding of heavy
metals in natural waters is, is not at all clear at the
present time, from the viewpoint of uptake of metals by
plant or animal life. It is possible, of course, for natural
complexing agents to solubilize heavy metals from
minerals. In the same way, there has been concern over
the possibility that man-made complexing agents such as
NTA may solubilize metals held in insoluble form. As far
as I am aware, there is no evidence that NTA used as an
additive in detergents could act in this way, because its
biodegradability would prevent the buildup of
appreciable concentrations.
Another form of binding of metals in natural waters is
by adsorption on inorganic colloids, for example, clays.
Both in natural waters and in soils, clays are known to
bind heavy metals very tenaciously so that only a very
small fraction of the metal content in waters or soils are
present in true solution. We have found, for example,
that a clay-rich soil heavily treated with additions of
soluble lead salt shows less than 1 ppm of soluble lead in
the soil moisture. Nevertheless, it turns out that a plant
can extract heavy metal from the insoluble as well as the
soluble components present in soil. This' will be
discussed in further detail later.
The biological effects of trace elements need a great
deal more thorough investigation. First of all, it is
simplistic to list elements as I have done without
specifying chemical forms. The widely differing toxic
effects of different forms of mercury are well known by
now, but the same situation must pertain to most
elements to greater or lesser extent. Thus chromium (VI)
is much more toxic than chromium (III). Cobalt is an
essential element to higher organisms in the form of
vitamin B,2 but useless and even toxic in inorganic
forms. Inorganic cobalt is converted to vitamin BI 2 only
by lower organisms, to which inorganic cobalt is
essential at low concentrations.
As mentioned previously, plant roots can extract trace
metals from forms that are insoluble in soil moisture.
This can be demonstrated by a simple experiment. If a
plant such as a corn plant is grown in a hydroponic
culture, containing lead, the uptake by the leaves or
stalks of the corn plant is roughly comparable to the
lead content of the liquid nutrient. That is, if a nutrient
contains a few micrograms per milliliter of lead or
cadmium ion, then the plant tissue on a dry weight basis
will contain a few micrograms per gram. On the other
hand, if a soil is treated with a clay containing lead, or
even with an insoluble form of lead such as lead sulfide,
then the plant tissues can take up much more lead than
would be indicated by the lead content of the soil
moisture (4). This can be attributed to the solubilizing
properties of the organic substances exuded by the
growing plant roots. This root exudate can be shown to
consist of a complex mixture of chemical compounds
including such materials as sugars, phenols, and proteins
which evidently are localized and concentrated in the
soil system whereas they are diluted in the hydroponic
system. In addition, soil bacteria can break down
insoluble salts such as sulfides, thus releasing the heavy
metal for plant uptake.
It is dangerous to generalize too quickly about the
behavior of trace metals based on simple chemical
analogies, because the biochemical mechanisms may be
greatly different. To illustrate this point, we might
contrast the behavior of lead and cadmium in relation to
plant uptake (5). These two metals are taken up in
comparable amounts from hydroponic cultures of corn
plants, insofar as comparisons of stalks or leaves are
concerned. On the other hand, if the roots are analyzed,
then we see a marked contrast. While both elements are
concentrated in the roots, the degree of concentration is
very much more pronounced for lead than for cadmium.
For example, a hydroponic culture of corn roots shows
an accumulation up to 3,000 ppm of lead and 200 ppm
of cadmium in the roots when both were grown in
solutions containing 20 ppm. It is found that the bulk of
the lead, perhaps 90 to 95 percent, can be readily
extracted from the intact root system by washing with a
complexing agent such as EDTA. A less efficient washing
can be achieved with a calcium nitrate solution. The lead
is largely contained on the outside rather than within the
interior of the root system. The root membrane seems to
represent a first line of defense against the entry of lead
into the plant. The exact form of the lead on the
surfaces of the roots is still unknown. It may be
considered as being ion exchanged but some recent
evidence from electron microscopy suggests the presence
of small nodules that are localized in character (6).
Another point of difference between lead and
cadmium is in the solubility of phosphates. Since
phosphates are naturally occurring constituents of all
-------
LUNCHEON REMARKS
43
living cells, it might be natural to expect the
precipitation of lead phosphate within cell tissues.
Indeed we have found some evidence for such
precipitation through scanning electron microscopy of
plant tissues containing relatively high concentrations of
lead. Incidentally, the first symptoms of lead poisoning
in a plant, as far as the plant physiologist is concerned, is
a leaf discoloration and curl characteristics of phosphate
deficiency. At the present time there is still some
uncertainty as to the precise form of the phosphate. It
has been known for several years that if lead acetate
solutions are applied to plant cells, a localized
precipitation of lead phosphate as lead hydroxyapatite
or hydroxyorthophosphate, Pb5(P04)3OH, is observed.
A report, as yet unverified, of the possible formation of
lead pyrophosphate, presumably arising through the
interaction of lead ion with pyrophosphate which is
known to be an intermediate in phosphate metabolism,
has appeared (7). Once the trace metal enters the plant
system in soluble form, it is rapidly translocated through
the plant. Apparently certain metals are strongly bonded
at membrane walls both in plant and animal cells.
Whether this might be regarded as a protective
mechanism or as an adverse effect, depends upon the
nature and function of the membrane.
Whether heavy metals can enter plants directly from
airborne particulates has not been clearly established.
Some authorities maintain that such particles have no
effects, apart from the possible blockage of stomata of
leaves, while others point to the fact that it is impossible
to wash all traces of metals, such as lead, from the
surfaces of leaves even with detergents or complexing
agents. Detailed examination of plant leaves by
techniques such as scanning electron microscopy should
help to resolve this question.
The entry of trace metals into the animal organism can
be through two principal routes, through ingestion of
food and water and through the respiratory system.
Experimental evidence indicates that ingested lead is
taken up quite inefficiently by the human body, perhaps
to the extent of 10 percent. The reason for this low
uptake has never been stated, but it would appear that if
the body has a defense mechanism against the
absorption of lead from the intestine, there may be a
disease corresponding to the breakdown of this
mechanism. Gearly, a detailed study is needed. Lead
breathed in as particulate matter is much more
efficiently absorbed, so that some authorities feel that
these two sources might be of the same order of
magnitude even though the intake through food
represents a much greater amount. In the blood stream,
perhaps 95 percent of the lead is associated with the red
corpuscles and only 5 percent with the blood serum. The
blood presumably represents the medium by which lead
is transported into the various organs, but the
quantitative rate law is unknown.
It is known that the skeleton represents a depository,
from which lead is only partially extractable and
presumably only under severe conditions such as
treatment with chelating agents. It is also known that
lead forms special nodules in kidney tissue, and it has
been inferred that these nodules are insoluble lead
protein complexes. Cadmium also concentrates in the
kidneys but because the protein complexes of cadmium
are more soluble, they do not form the same type of
nodules. Cadmium has a pronounced effect upon the
blood pressure, presumably through its action upon the
kidneys.
Children appear to be much more susceptible to nerve
damage and brain damage by lead poisoning than do
adults. The reason is not at all clear, and therefore it
appears to be difficult to assign a threshold level of
blood lead content below which no damage can be
detected. Some authorities, notably Kehoe, have
regarded 80 micrograms per 100 milliliters as a safe
limit, whereas other authorities have felt that 40
micrograms or even 36 might be more realistic and safer
limits (8). Where we draw the line makes a great deal of
difference, because most children exhibiting 80
micrograms of blood lead and showing symptoms of
poisoning have been demonstrably exposed to sources
such as paints. On the other hand, 15 to 20 percent of
children in clinical tests in downstate Illinois have shown
blood lead contents over 40 micrograms (9). Authorities
in England have recently placed much more stress on the
possibility of lead from automotive fuels representing an
important contribution to the poisoning of children than
have authorities in this country (8).
When we attempt to describe the effects of trace
metals in biochemical terms, we are confronted with
more ignorance than knowledge.
Biological effects of trace metals can be described at
various organizational levels, namely: the organism or
whole plant or animal, the organ, the cell, the organelle,
the membrane, and finally the molecular level. As we
proceed down the organizational scale, the depth of our
ignorance increases except that finally at the molecular
or enzymatic level once more we find some positive
knowledge. Clinical studies on lead poisoning reveal
effects like mental retardation and disturbances of the
nervous system at the organism level. Concentrations in
certain organs, for example the kidney, are well
established. At the cellular level, interference with the
energy-conversion process have been established, and
this can be traced to the subcelJular, or organelle level, in
that isolated mitochondria both from plant and animal
cells show the toxic effects. When we reach the
membrane level, we find references to preferential
binding, but little detail as to the mechanism of the
binding, or effects on transport rates through the
membrane. At the molecular level, we find vague
references to the binding of metals to sulfhydryl groups
of enzyme systems and speculations as to the relative
effects of metals based on the stabilities of
-------
44
CYCLING AND CONTROL OF METALS
sulfhydryl-containing chelates, but little that is solid and
well established. I am generalizing here, and referring to
toxicity and not to specific biochemical systems, such as
hemoglobin, vitamin BI 2 and chlorophyll, which involve
trace metals in well defined roles.
Among the areas requiring further research are the
protective mechanisms for trace metals especially among
the higher organisms, both plant and animal. These
protective mechanisms could include such phenomena as
preferential binding to membrane surfaces, precipitation
as inorganic salts or organic derivatives, complexation by
biological chelating agents, etc. An almost completely
unexplored area is the question of the combined effects
of two or more trace metals. Are the effects additive,
competitive, or synergistic? If each metal taken
separately has a certain tolerance level, what is the
tolerance level for a mixture of two metals? Are the
protective mechanisms for two or more metals
independent of one another?
In summary, a great deal of comprehensive work is
needed on the effects of trace metals on the total
environment. This work must consider both extremes
and all intermediate organizational levels, and it must
consider the interactions among the trace elements as
well as their individual effects. Both the short-term and
long-term effects need consideration. By long-term, I
mean a time period commensurate with the life span of
the entity under consideration. If we are dealing with
human beings, this means a period of the order of a
century, but if we are dealing with cells, it might be a
much shorter period. If we are considering effects to
mankind as a species, we need to look at truly long-term
effects, over time spans of hundreds or thousands of
years.
REFERENCES
1. Goldwater, L. J, Industrial Medicine, 41, 13,1972.
1. Lagerwerff, J. V., N. C. Brady, Ed., pp. 343-364 in
AAS Publication #85, 1967.
3. Bender, M. E., W. R. Matson, R. A. Jordan,
Environmental Science and Technology 4 520
1970.
4. Braids, O. C., University of Illinois NSF-RANN
project, unpublished results.
5. Koeppe, D. E., R. Root, R. R. Gadde, University of
Illinois, NSF-RANN project, unpublished results.
6. Malone, C., University of Illinois NSF-RANN project,
unpublished results.
7. Skogerboe, R. K.,Colorado State NSF-RANN project,
private communication.
8. Smith, D. B., Biologist, 18, 52, 1971; Chemistry in
Britain,!, 54, 284,1971; 8, 240,1972.
9. Fine, P. R., et. al., J. Am. Med. Assn., 221, 1475,
1972.
-------
SESSION II
TRANSPORT AND EFFECTS
Chairman:
H. Wiser
U. S. Environmental Protection Agency
-------
PHYSICAL TRANSPORT OF TRACE METALS IN THE
LAKE WASHINGTON WATERSHED
R. S. BARNES AND W. R. SCHELL
University of Washington
Seattle, Washington
INTRODUCTION
The biogeochemical cycle removes material from the
lithosphere, redistributes it throughout the atmosphere
and hydrosphere and ultimately reincorporates it into
the lithosphere. This continuous cyclic process includes
weathering, erosion, transport, and deposition. The
transfer rates and amounts of material participating in
this cycle can be accelerated, for example, by poor land
management practices, or by increasing the input of
material as byproducts of technological developments.
By this latter means man has introduced quantities of
trace metals into the environment. These trace metals
are frequently transported easily and are injected
directly into the major transport pathways of the
environment. The amount of increase of these trace
metals in a specific environment can be measured in
recent sediment profiles where the time history of
deposition can be established.
Geochemical Cycle
The geochemical cycle consists of source, transport,
and sink. The natural source of trace metals is the
lithosphere; artificial sources have been created by
industrialization and urbanization; transport occurs by
wind, water and ice; the sinks are fresh water lakes,
rivers or the oceans. The most significant modes of trace
metal transport are by wind and water as shown in Table
1, where amounts of heavy metals produced and the
potential transport to the ocean are given.
The removal of trace metals to a geochemical sink
must include an aqueous phase. Removal processes
occurring can include absorption, precipitation,
oxidation, reduction, and complex formation. Because
of the rapid removal processes, in general, many trace
metals are lost from the aquatic environment within a
short distance from the initial input (1, 2). The
concentrations of trace metals in water are low and were
TABLE 1 GLOBAL TRACE METAL PRODUCTION AND POTENTIAL OCEAN
INPUT*
Element
Pb
Cu
V
Ni
Cr
Sn
Cd
Hg
Mining
production
(106 tons/yr)
3
6
0.02
0.5
2
0.2
0.01
0.009
Transport by
rivers to oceans
(106 tons/yr)
0.1
0.25
0.03
0.01
0.04
0.002
0.0005
0.003
Atmospheric
washout
(106 tons/yr)
0.3
0.2
0.02
0.03
0.02
0.03
0.01
0.08
Ratio
aeolian/
fluvial
3.0
0.8
0.7
3.0
0.5
15
20
27
* Reference 3.
45
-------
46
CYCLING AND CONTROL OF METALS
difficult to measure until recent improvements were
made in analytical techniques. The analytical difficulties
of the past have contributed to the limited
understanding of the geochemical cycle of many trace
elements. It is through a greater understanding of the
geochemical cycling of trace metals that insight can be
gained on problems of pollutants in the aquatic
environment.
Modes of Physical Transport
The major modes of physical transport are advection
and diffusion. The advective processes are by far the
most important in the transport of most trace metals in
the atmosphere or hydrosphere on a global scale. For
certain volatile trace elements such as mercury, the
diffusion process from the lithosphere would dominate.
Three modes of advective transport of trace metals are
(a) that which is carried by the wind (aeolian), (b) that
which is carried by running water either suspended or
dissolved (fluvial), and (c) that which is removed or
transported by rain or other forms of precipitation
scavenging (pluvial). The settling of particles under the
influence of gravity is a major mode of vertical
transport.
Aeolian transport was noted as early as the 12th
century (4). Meridional and zonal dust transport have
been observed from the Sahara- to the mid-European
continent (5), and from Africa to the Caribbean (6),
volcanic eruptions such as Krakatoa spread volcanic dust
worldwide. Radioactive fallout originating from
Eniwetok, Bikini, and Novya Zemyla, USSR, and Lop
Nor, China, has been followed around the world. These
sources have served as tracers of geochemical processes
and have permitted calculations of residence times and
transit times in the atmosphere to be made (7—10); the
input of the radioactive tracers into the hydrosphere has
permitted similar calculations to be made in the oceans
and freshwater areas (11-13). The recent findings on
the build up of lead and mercury in Greenland ice
profiles illustrate long range aeolian transport of these
trace metals (14, 15). High concentrations of trace
metals in surface air of North American cities indicates
that short range aeolian transport is considerable (16).
Significant quantities of iron, zinc, arsenic, silver,
antimony, cobalt and mercury were found near Toronto
(17); in the Chicago area concentrations in excess of
10-9 g/m3 were found for iron, zinc, manganese,
vanadium, antimony, chromium, mercury, aluminum,
cerium, silver, and selenium (18).
It is apparent that the trace metal input to the
atmosphere and hydrosphere follows the transport
processes of the geochemical cycle. The problem arising
from local pollution sources of trace metals may be
exported thousands of kilometers from the point of
origin. The pollution from industrialized nations then
becomes an international concern. It is clear that
effective control of potential trace metal pollutants can
be exercised only at the source where the quantity am
chemical form can be regulated.
Sediment Method
The evaluation of contemporary transport am
distribution of trace metals in a given region can b<
achieved by systematic collection and analysis of air anc
water samples, dry fallout, precipitation, soils anc
sediments. While this comprehensive technique ii
satisfactory for evaluating contemporary events, ii
cannot determine the history of trace metals in a giver
region. To determine the history of trace metal build uf
in a given region, soil and sediment profiles are mosl
suitable. Because of weathering, natural mixing, and
disruption by human activities, undisturbed soil profiles
are difficult to obtain. However, sediment cores often
are uniquely suited for the preservation of the trace
metals history.
Sediment cores for trace metals have the following
advantages:
1. relatively independent from weathering,
2. sedimentary deposits, in general, increase at a fairly
constant rate per year,
3. sedimentary material serves as scavengers for trace
metals,
4. usually are outside the sphere of human modification
but frequently contain an anthropogenic anomaly
that can be specifically dated.
Two basic assumptions are necessary in using sediment
BELLINGHAM
SCALE IN KILOMETERS
16 0 16 32
I ' ' ' I 1 1
Figure 1. Puget Sound basin.
-------
TRACE METALS - PHYSICAL TRANSPORT
47
cores for the trace metal history; first, the system must
be closed to gains and losses of the trace metal at all
levels in the core and second, a sequential accumulation
must have taken place. Since the man-made increase in
trace elements has occurred in recent years, it is essential
to have time resolution to within a few years.
Practically, this demands a sedimentation rate of greater
than about two mm/yr.
The application of sediment cores to the time history
of trace metals in Lake Washington has been made.
Figure 1 shows the Lake Washington area and the major
drainage basin, the Cedar River. The urban and suburban
development of the region has been increasing rapidly
since about 1940. Lake Washington has an area of 88
km2 and a mean depth of 33 meters. The City of
Seattle lies along the western shore with suburban
development surrounding the lake. It is spanned by two
floating bridges completed in 1941 and 1963. A ship
canal and locks were built in 1916 which connected the
lake with Lake Union and Puget Sound. This lowered
the lake some 3 m to its current elevation of 4.3 m
above mean sea level. To maintain sufficient flow of
water to operate the locks, the Cedar River, with an
average flow of 19 m3/sec, was permanently diverted
into the southern end of the lake in 1916.
The lake has a history of cultural eutrophication (19)
but little direct industrial waste discharge is believed to
have occurred. Recovery from cultural eutrophication
has been rapid since 1968 (20). The City of Renton is
located on the Cedar River where Boeing and Pacific Car
and Foundry plants are potential major industrial
sources of trace metals.
RESULTS AND DISCUSSION
Mercury
The core locations for sampling trace metals are shown
in Figure 2. The mercury profiles for the three cores
taken are shown in Figure 3. The magnitude of local
variations is shown by duplicate cores from station 2;
the absolute concentrations are initially 60 percent
different at the surface. A fixed point in time has been
found at the 18 cm level at station 2 (21) and 25 cm at
station 4 when the Lake Washington Ship Canal and
Government Locks were constructed. A silt band was
produced when the Jake level was lowered three m and
the Cedar River diversion was completed in 1916. On
this basis the sediment rate was found to be 3.3 mm/yr
for station 2 in agreement with reported values at a
nearby location (21). For station 4, by a fitting of the
similar mercury structure, and the silt layer, a
sedimentation rate of 4.4 mm/yr is indicated. This is
consistent with the core location which was closer to the
Cedar River, a major source of sediment material.
The discrepancy between stations is in the absolute
magnitude of the mercury concentration. The similarity
in profiles indicates that general lake conditions are
SAMMAMISH
RIVER
MERCER ISLAND
BRIDGED
LAKE WASHINGTON
Figure 2. Lake Washington core sampling locations.
being reflected. It is apparent that the mercury
associated with the larger sedimentation rate has a lower
concentration; the total mercury available to the
sediment, however, can be constant.J"he dilution by low
mercury sediment could account for the discrepancy
between the cores from station 4 and station 2. The
difference in sediment rate is ca. 33 percent, whereas the
differences in absolute concentrations is ca. 50 percent,
and probably within the error of the sampling and
analysis. The source of mercury to the sediments must
be dispersed throughout the lake. This would indicate
that the mercury is being transported either by aeolian
processes or that the mercury in the lake is added at
about the same rate throughout. The dramatic decrease
at 4 to 6 cm for all elements represents what is believed
to be redistribution of silt due to the construction of the
second floating bridge, completed in 1963. These core
section samples had high silica content in contrast to the
other samples. The X-ray radiographs of cores taken
nearby show a density anomaly at the same depth which
could be attributed to the bridge construction (21).
Additional cores have been taken to attempt to define
local and areal distribution of the mercury input.
At the present time it is not possible to separate out
the several suspected sources which contribute to the
mercury budget of the lake. Suspected sources for
-------
48
CYCLING AND CONTROL OF METALS
mercury include: combustion of fossil fuels, especially
coal; aeolian and aeolian-fluviaJ transport from the
Tacoma smelter; municipal sewage or treated effluents;
local industrial or domestic sources such as mercury in
marine paints, fungicides, etc. The mercury associated
with sewage wastes and storm runoff should be
PPM MERCURY
0.8
0.4
1971
-1881
J1866
Figure 3. Mercury in Lake Washington cores.
I
i—
a.
LU
Q
10
20
30
40
50
100
PPM LEAD
150 200
250
300
STATION 2
EVERGREEN POINT BRIDGE
1971
1956
1941
1926 =
1911
1896
1881
1866
1851
D
o
Figure 4. Lead in Lake Washington core.
-------
TRACE METALS - PHYSICAL TRANSPORT
49
diminishing now following the diversion of sewage from
the lake in 1968.
Lead
The lead profile is shown in Figure 4 for a core from
station 2. The gross structure of the lead concentration
is similar to the mercury core with the increase starting
at the 18 cm level. The lead content is shown to increase
by about a factor of 16 from the base line prior to 1916.
The present sediment concentration of about 300 ppm
indicates a continuous and increasing input source. The
doubling time for the increase in lead concentration is
about 18 years.
The fine structure of the core can be related to
specific events by assuming the sedimentation rate of 3.3
mm/yr and no migration of the lead after deposition.
The initial increase from base line at 18 to 20 cm depth
can be ascribed to the diversion of the Cedar River. The
Cedar River drainage basin is about 500 km2 in area and
is generally downwind (E—NE) of a potential source, the
American Smelting and Refining Company Smelter, in
Tacoma. This smelter has been in operation since 1890
and processed ore mainly for lead from 1890 to 1913;
current stack emissions may be as much as 40 percent
lead oxide. (22). Aeolian transport would bring lead to
the drainage basin and then by fluvial transport into the
lake via the Cedar River. The second rapid increase at
the 14 to 15 cm level would correspond to the 1920's
when lead alkyls were introduced in gasoline. The
decrease in the lead deposition from the 14 to 9 cm
levels would correspond to the depression and war years.
The use of gasoline engines, predominately in the
automobile, may be directly related to the lead profile.
The 9 to 0 cm level represents the post war period when
automobile use had increased rapidly with a
corresponding increase in lead concentrations.
The concentration of lead is increasing at a rapid rate
in the sediment core. It is possible that the proximity of
the station to the bridge, 400 m to the south, may be
responsible for the high concentrations measured.
Additional core samples taken recently should better
define the local and areal distribution of lead in Lake
Washington sediments.
Zinc and Copper
The zinc and copper concentration profiles shown in
Figure 5 are similar to those of mercury and lead. The
rapid increase in concentration of zinc occurred at about
the 16 to 17 cm level with the characteristic minimum at
the 6 cm level shown in both zinc and copper. Zinc and
copper concentrations have increased by about a factor
of four over the base line values prior to 1916. The
present concentrations for zinc at 230 ppm and copper
at 50 ppm have not increased much since 1950.
The sources of zinc and copper to the lake include
natural mineral deposits in the Cedar River watershed,
aeolian transport from the smelter in Tacoma and
domestic and industrial uses of zinc and copper in
algicides, pesticides, paint, galvanized steel.
PPM HEAVY METALS
1971
1956-
1941-
1926^
1911-
1896-
1881
1866^
1851
1836
) 50 100 150 200 25
1 I 1 1
^s1^ Cu _ ^— — ^^"
* -> ^^ Zn
0 (
0
) 25 50
i |
1-^
^^
r l_ ^^ A ^
j* 3D ___ ^. — - « ^
10+ / ,/-""
/ /
/ /
-— ~ /
t> i 5
'
j x
y
- \ <( i ^
^ \ ^~
( ) S; .
1 /
30|
1 f >
j C STATION 2 1
STATION 2
1971
1956
1941
1926
1911
1896
1881
1866
^ \ EVERGREEN POINT BRIDGE " 40 1 EVERGREEN POINT -j 1851
's
BRIDGE
-I 1836
Figure 5. Copper, zinc, antimony and arsenic in Lake Washington core.
-------
50
CYCLING AND CONTROL OF METALS
PPT IRON
25 50
u
Z
I
i—
Q.
LU
O
STATION 2
EVERGREEN PT
BRIDGE
PPT SODIUM
1.0
—i 1—
10 -
20
30
STATION 2
EVERGREEN PT
40 ABRIDGE
2.0
— 1971
CEDAR RIVER FLOW m3/s
0 10 20
1956
1926
\ 1911
J1896
i
i 1881
1866-
1851
10
—i—
30
—i—
O
o
>
Figure 6. Iron and sodium in Lake Washington core; Cedar River annual discharge averaged over 3-year increments.
Arsenic and Antimony
The few data points for arsenic and antimony are
shown in Figure 5 measured by neutron activation
analysis. The locations in the core were selected after the
other trace metals were analyzed to observe if these
elements were following the same pattern. The same
general pattern of concentrations was followed.
Migration of the arsenic from a fixed point of deposition
could occur since a volatile arsenic compound, AsH3,
could be formed in the reducing environment of the
sediment. This elemental migration does not appear to
be taking place at a rapid rate which would perturb the
pro! He concentrations. By inference, the mercury
migration should be low, indicating that the elements
studied, which have been deposited in the lake
sediments, do not migrate at a significant rate. A more
detailed profile is needed for arsenic and antimony,
especially in the upper layers.
The increase from natural background prior to 1916
has been about five times for arsenic and antimony. The
sources for these trace metals are probably aeolian
transport from the smelter in Tacoma. The arsenic
concentration increase may also be from the municipal
sewage where herbicides and insecticides have been used
extensively on gardens, and from arsenic contained in
detergents.
Iron and Sodium
The iron and sodium profiles are shown in Figure 6.
Since these elements are major constituents of the
erosion process, the concentration, as a function of time
(depth), indicates differences caused by natural changes
in the watershed, which drains into the lake. The profile
shows fluctuations around a mean value of about 40 ppt
iron and 1.2 ppt sodium. There is no apparent long term
trend in the concentrations of sodium and iron in the
sediment data, in contrast to trends of the other trace
metals measured. The minimum at the 6 cm level is again
evident and for both metals. There appears to be a slight
increase at the 16 to 18 cm level when the lake level was
lowered and the Cedar River diversion was completed.
The erosion rate depends on the rainfall and should
TABLE 2 REPRESENTATIVE TRACE METAL CON-
CENTRATIONS IN LAKE WASHINGTON
IN, mg/liter
Element
Fe
Na
Pb
Zn
Cu
Hg
Average
fluvial
input
0.055
3.43
0.0009
0.026
0.0025
0.00005
Average
fluvial
output
0.033
4.70
0.00085
0.023
0.003
0.00005
Observed range
in lake
0.010-0.095
4.45-5.00
0.0003-0.0012
0.004-0.047
0.0011-0.0079
0.000008-0.000068
-------
TRACE METALS - PHYSCIAL TRANSPORT
51
correlate with runoff. Figure 6 shows the general
correlation of iron and sodium concentrations with the
Cedar River discharge, using the discharge as a measure
of total watershed runoff. A study of post-glacial lake
sediments in Northern England showed that the relative
concentrations of alkalai metal elements in sediment was
related directly to the intensity of erosion, for example,
rainfall in the drainage basin (23). Under rapid erosion
conditions less sodium, for example, was leached from
the soil particles and proportionately more was carried
by the sediment load for deposition into the lake.
Similarly, in the Lake Washington drainage basin high
rainfall and subsequent high runoff produced sediments
with high sodium concentrations.
This same process should occur for other
macro-constituents of the sediment such as iron and
manganese. However, unlike sodium, chemical and
biological reactions can release these metals in the
sediment under certain pH and redox conditions. These
conditions do not appear to be occurring in the Lake
Washington sediments.
Budget
The transport of trace metals to the lake is reflected in
the core profiles. Iron and sodium, for example,
correlate with the discharges of the Cedar River,
indicative of fluvial transport. The modes of transport
for the other trace metals are not evident from the core
profiles alone, but require geochemical budget
calculations to indicate the relative importance of wind
and water processes. The preliminary data on
measurements, by atomic absorption spectrometry, of
trace metal concentrations are shown in Table 2. Fluvial
input data were obtained from the Cedar River and
Sammamish River inlets to the lake, while the outlet
data were obtained from stations in the lake near the
eastern end of the ship canal.
The budget calculation method has simplified the
geochemical system into: fluvial and aeolian inputs, a
sedimentary sink, and fluvial output. The aeolian input
of trace metals was assumed to be relatively insoluble
(24). The complex processes of redistribution within the
lake were neglected in this first approximation since
only input and output were needed in the budget
computations.
The input and output concentrations indicate that,
with the exception of sodium and iron, the trace metal
concentration in the water is not greatly changed by
passage through the lake. The data shown in Table 3 are
based on an average inflow of 1.17 x 109 m3/per year
with an incoming sediment load of 50 x 106 kg/per year
(25) and the data from Table 2; it is assumed that the
incoming sediment has a composition representative of
crustal materials. The aeolian input was estimated by
subtracting the net fluvial input from the annual
sediment input. An independent check of the input of
iron and sodium by aeolian transport, using dustfall
data, indicates that the estimated aeolian values are
probably high by a factor of four, on the basis of net
transport. This is not considered a serious error for
sodium because of the large magnitude of the numbers
involved. The discrepancy in iron is probably due to
insufficient iron data; since iron is both biologically and
chemically active in the aqueous environment, adequate
sampling is difficult.
In contrast to iron and sodium, the heavy metals show
very different transport effects. While the annual fluvial
input is approximately equal to the amount deposited in
the sediments for zinc, copper, and mercury, the net
fluvial transport, input-output, retained in the lake
sediments amounts to only 32 percent, 44 percent, and
7 percent, respectively. This indicates substantial aeolion
contributions for all these metals. The aeolian transport
TABLE 3 TRACE METAL BUDGET FOR LAKE WASHINGTON
Elements
Fe, tons
Na, tons
Pb, tons
Zn, tons
Cu, tons
Hg,kg
Input
2570
5420
1.3
34
5.7
62
Annual
Fluvial
output
40
5440
1
27
3.5
58
transport
Net
2530
(-)20
0.3
7
2.2
4
Aeolian
input
2200*
180f
29.8
15
2.8
56
Annual
deposition in
sediments
(measured)
4700
160
30
22
5
60
*Based on an average dustfall for Seattle (26) of 38.92 U. S. tons/mi2/mon =
14.8 x 106 kg/yr over Lake Washington, and using an average iron concentration
of 3400 ppm for urban dust (18), the iron input due to aeolian transport would
be on the order of 500 tons/yr.
t Based on (*) above, Na input is 45 tons/yr from aeolian transport; even if a
higher Na concentration is assumed because of marine aerosols, the aeolian
component is still very small compared to the fluvial.
-------
52
CYCLING AND CONTROL OF METALS
for lead is even more striking; just considering the input,
about 10 times as much lead enters the lake from the air
as by fluvial means. Using lead concentrations in dustfall
for Seattle (26), the input from the atmosphere to the
lake is estimated to be 24,000 kg/per year, which is in
good agreement with the estimated atmospheric
contribution of 29,750 kg/per year.
Another way of approaching these input calculations
is to consider the nature of the trace metal enrichment
in the sediments since 1916. Table 4 shows the
enrichment in the contemporary surface sediment
relative to the pre-1916 sediment. Table 5 shows the
contemporary aeolian input of heavy metals to the
sediments, as estimated from the enrichment of these
metals in the present sediment, assuming that the
enrichment since 1916 is due entirely to aeolian
material. This estimate is compared to that for aeolian
input, as derived from the net transport budget in Table
3. The results are striking for lead and mercury in
particular, where both methods of calculation indicate a
very high aeolian component. Copper and zinc also show
substantial aeolian contributions, but the percentages are
not as large as those of mercury and lead, reflecting the
higher natural backgrounds of copper and zinc in the
core.
TABLE 4 TRACE METAL ENRICHMENT IN LAKE
WASHINGTON SEDIMENTS SINCE 1916
Element
Fe
Na
Pb
Zn
Cu
Hg
Enrichment ratio
1971/pre-1916
1
1
16.6
3.9
3.6
10.0
Based on the lake volume, fluvial output and
sedimentary deposition, the following mean residence
times were estimated: iron, 11 days; lead, 26 days;
mercury, 15 months; copper, 16 months; zinc, 21
months; and sodium, 29 months. The mean residence
time for the lake water is also 29 months. Such figures
must be considered very rough approximations, as the
assumption of complete mixing time, being much less
than the mean residence time, does not appear valid
during periods of stratification, June to October, at least
for iron and lead; nevertheless, the ordering of mean
residence times Fe < Pb < Hg < Cu < Zn < Na is
identical to those estimated for these trace metals in the
ocean (27).
There is evidence that the trace metals are primarily
transported in the suspended load, often in inert
positions within the suspended particles (28). A further
observation is that much of the detrital trace metals
never leave the solid phase from initial rock weathering
TABLES PERCENTAGE OF CURRENT HEAVY
METAL INPUT TO LAKE WASHINGTON
SEDIMENTS ATTRIBUTED TO AEOLIAN
PROCESSES AS ESTIMATED FROM
TRACE METAL ENRICHMENT AND
BUDGET DATA
Element
Contemporary aeolian input
to sediment
Pb
Zn
Cu
Hg
Enrichment*
94%
74%
72%
91%
Budgetf
99%
68%
56%
93%
* Assuming that all the heavy metal enrichment since 1916 is
due to aeolian transport.
fOn a net transport basis.
to detrital deposition. This is demonstrated by the Lake
Washington sediments, where the trace element
composition more nearly reflects that of the crustal
materials in the suspended load, rather than that of the
incoming water. Lead, entering the lake from the
atmosphere, appears to have a very short residence time
in the water column, as shown by the low
concentrations measured in the water, and by mean
residence time estimates. It is suspected that the same is
true for other heavy metals in atmospheric material, but
our data can not confirm this.
SUMMARY
In the Lake Washington drainage, trace metal
enrichment appears to be correlated with the cultural
development of the region, and is brought into the local
hydrosphere principally by advective atmospheric
transport. Fluvial processes are of considerable
significance, but appear to be reflected in the sediments
primarily on the basis of the suspended load. It has been
found that trace metal analysis of recent lake sediments
can provide meaningful data concerning the impact of
man on his environment, and offers a unique
opportunity for evaluating past environmental
conditions.
ACKNOWLEDGMENT
This study was supported by U.S. Environmental
Protection Agency grant number R-800357.
REFERENCES
l.Turekian, K.K., Rivers, tributaries, and estuaries,
9-74, In D.W. Hood (ed.), Impingement of Man
on the Oceans, Wiley-Interscience, 1971.
2. Cranston, R.E. and D.E. Buckley, Mercury pathways
in a river and estuary, Environ. Sci. Technol.
6:274-278,1972.
3.National Academy of Sciences, Marine
Environmental Quality: Suggested Research
Programs for Understanding Man's Effect on the
-------
TRACE METALS - PHYSICAL TRANSPORT
53
Oceans, National Academy of Sciences, 107,
Washington, D.C .,1971.
4. Rex, R.W. and E.D. Goldberg, Insolubles, 295-304,
In MJSf. Hill (ed.), The Sea, Vol. 1, Physical
Oceanography, Wiley-Interscience, 1962.
S.Walther, J.,Der grosse Staubfall von 1901 und das
Lossproblem, Naturwiss. 18:603-605, 1903.
6. Brown, W.F., Volcanic ash over the Caribbean, June
1951, Monthly Weather Rev. 80:59-62, 1952.
7.Pierson, D.H. and R.S. Cambray, Interhemispheric
transfer of debris from nuclear explosions using a
simple atmospheric model, Nature
216:755-758,1967.
S.Krey, P.W. and B. Krajewski, Comparison of
atmospheric transport model calculations with
observations of radioactive debris, J. Geophys.
Res. 75:2901-2908,1970.
9. Fabian, P., W.F Libby, and C.E. Palmer,
Stratospheric residence time and
interhemispheric mixing of strontium 90 from
fallout and rain, J Geophys. Res.
73:3611-3616,1968.
10. Schell, W.R., G. Sauzay, and B.R. Payne, Tritium
injection and concentration distribution in the
atmosphere, J. Geophys. Res. 75:2251—2266,
1970.
11. Walton, A., M. Ergin, and DJD. Harkness, Carbon 14
concentrations in the atmosphere and carbon
dioxide exchange rates, J. Geophys. Res.
75:3089-3098,1970.
12.Suess, H.E., The transfer of carbon 14 and tritium
from the atmosphere to the ocean, J. Geophys.
Res. 75:2363-2364,1970.
13. Rafter, T.A. and B.J. O'Brien, Exchange rates
between the atmosphere and the ocean as shown
from recent C14 measurements in the South
Pacific, Paper presented at the Twelfth Nobel
Symp. on Radiocarbon Variations and Absolute
Chronology, Uppsala, August 1969.
14. Murozumi, M., TJ. Chow, and C. Patterson,
Chemical concentrations of pollutant lead
aerosols, terrestrial dusts, and sea salts in
Greenland and Antarctic snow strata, Geochim.
Cosmochim. Acta 33:1247-1294,1969.
15. Weiss, H.V., M. Koide, and ED. Goldberg, Mercury
in a Greenland ice sheet: evidence of recent
input by man, Science 174:692-694,1971.
16. Tabor, E.C. and W.V Warren, Distribution of certain
metals in the atmosphere of some American
cities, AJvlA. Arch. Ind. Health 17:145-151,
1958.
17. Lee, J. and R.E. Jervis, Detection of pollutants in
airborne particulates by activation analysis,
Trans. Amer. Nucl. Soc. 11:50-51, 1968.
18. Briar, S.S., D.M. Nelson, J.R. Kline, P.P. Gustafson,
E.L. Kanabrocki, C.E. Moore, and DM. Hattori,
Instrumental analysis for trace elements present
in Chicago area surface air, J. Geophys. Res.
75:2939-2945,1970.
19. Edmondson, W.T.,Eutrophication in North America,
124 — 149, In Eutrophication: Causes,
Consequences, Correctives, National Academy of
Sciences, Washington, D.C., 1969.
20. Edmondson, W.T., Phosphorus, nitrogen and algae in
Lake Washington after diversion of sewage,
Science 169:690-691,1970.
21. Edmondson, W.T. and D.E. Allison, Recording
densitometry pf X-radiographs for the study of
cryptic laminations in the sediment of Lake
Washington, Limnol. Oceanog. 15:138—144,
1970.
22. Crecelius, E.A. and D.Z. Piper, Unpublished
manuscript, Department of Oceanography,
University of Washington, Seattle, 1971.
23.Mackereth, F.J.H., Chemical investigation of lake
sediments and their interpretation, Proc. Roy.
Soc. (London) B 161:245-309,1965.
24. Cholak, J., L.J. Schafer, and R.F. Hoffer, Results of
a five-year investigation of air pollution in
Cincinnati, A.M.A. Arch. Indust. Hyg.
6:314-325,1952.
25.Puget Sound Task Force of the Pacific Northwest
River Basins Commission, Puget Sound and
Adjacent Waters, Appendix III, Hydrology and
Natural Environment, 205,1970.
26. Johnson, R.E., A.T. Rossano, Jr., and R.O.
Sylvester, Dustfall as a source of water quality
impairment, J.S.ED., Proc. Am. Soc. Civil
Engineers 92:245-267,1966.
27. Goldberg, ED., The oceans as a chemical system,
3-25, In M.N. Hill (ed.), The Sea, Vol. 2, The
Composition of Sea-Water, Comparative and
Descriptive Oceanography, Wiley-Interscience,
1963.
28.Turekian, K.K. and M.R. Scott, Concentrations of
Cr, Ag, Mo, Ni, Co, and Mn in suspended
material in streams, Environ. Sci. Technol.
1:940-942,1967.
-------
BIOLOGICAL UPTAKE AND DISTRIBUTION OF
LEAD IN ANIMALS*
J. Abdelnour
University of Illinois
Urbana-Champaign, Illinois
The widespread use and distribution of heavy metals
and other contaminants in the environment have created
the need for the development of models that are able to
predict the uptake, accumulation and distribution of
these contaminants in living organisms. These models,
when coupled with studies on effects and alterations
that these contaminants might inflict on the
environment and its components, become extremely
valuable to the decision maker.
Part of the effort undertaken by the interdisciplinary
study of heavy metals, currently taking place at the
University of Illinois under grant from the National
Science Foundation, is to develop predictive models for
heavy metals in general, and lead in particular. This
paper will present a model that has been developed in
the modeling team of the heavy metal study. The basic
concepts of the model are general enough to make them
applicable to many biological uptake and retention
phenomenas. The model belongs to a class, usually,
known as compartmental models or, more specifically,
first order linear models. The first order assumption, in
the studies of biological uptake and accumulation, was
suggested for radionuclides and other heavy metals by
the International Commission on Radiological
Protection (1). Many models of this type have been
developed for a variety of purposes, ranging from milk
contamination in cows by radionuclides (2, 3), to DDT
accumulation (4), to retention of ingested elements by
animals (5).
The following model is a multi-compartment, first
order linear model to study the uptake, retention, and
elimination of heavy metals by animals. Conceptually, it
is applicable to all mammals and most contaminants.
The body is divided into as many organs of interest as
desired, and different types of input are considered. The
main emphasis here will be on lead. The basic
assumptions of the model are:
*Sponsored by National Science Foundation, NSF IRRPOS
GRANT GI-26 and NSF RANN GRANT GI-31605.
1. The transfer of the contaminant, namely lead, within
the animal is accomplished via the blood.
2. The uptake and elimination of the contaminant
follow a first order law. This implies that the
instantaneous transfer rate from any given organ is
directly proportional to the amount present in the
organ.
Mass equilibrium is satisfied at any given organ, and for
the body as a whole.
Figure 1 shows a schematic diagram of the physical
flow of lead within the body. In this particular model,
two types of input are considered. The lead from air via
respiration, and the lead ingested with food and water.
Other possible modes are neglected. Three types of
output are also considered. These are the output via the
urine, feces, and lead exhaled. Other means of output
are neglected.
The conceptual or compartmental model
corresponding to Figure 1 is shown in Figure 2. In this
particular abstraction, the function of an organ is
separated from its physical entity. The concentration of
lead in the urine is assumed, here, to be proportional to
the concentration of lead in the blood rather than the
concentration of lead in the tissue of the kidney. Other
interpretations could be used. The mathematical model
describing the uptake and elimination of lead, as derived
from Figure 2, is given by a set of first order linear
differential equations with constant parameters. Each
equation satisfies equilibrium at a given organ. Each
equation states that the rate of change in accumulation
within a given organ, is equal to the uptake rate minus,
the elimination rate.
The input rates to the system
R1
Rair =N(BR) • (CA) • (XA)
fd
n=l
(IRn)
(Xn)
(1)
(2)
55
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56
CYCLING AND CONTROL OF METALS
The output rates from the system are given as
FE >.f iBLi
Rfd>
FE Xf • (BLI + i (CEn) • (InI • (1 Xn) (3)
n=l
UR AU (BL) (4)
The equilibrium equations describing the behaviour of
the system are:
d(Kl) =
KD + X'KI
(5)
-^ -XL • (L) + X'L • (BL)
d(BO)
-*BO
X'BO
d(T)
= -xM • (M) + x'M
= -XSP • (SP) + X'sP • (BL)
- -XT • m + X'T • (BL)
(6)
(7)
(8)
(9)
(10)
d(BL) = - d(KI) - d(L) - d(BO) - d(M) - d(SP) - d(T)
+ Rair + R'fd *'u (BL) X1 f (BL)
AIR INHALED
INGESTION
AIR FXHALED T
-* IRESP. TRACT]
BLOOD
\
IG.I. TRACT) —
/^~~
. , EXCRETION
, _ , , _ , , _ , , _ ,
|LIVER| |BONE| |MUSCLE| |SPLEEN|
.EXCRETION
Figure 1. Schematic of physical flow of lead in the body.
Figure 1. Compartmental model of flow of lead in body.
-------
LEAD BIOLOGICAL TRANSPORT
57
Where:
KI, L, BO, M, SP, BL represent the amount of lead,
respectively, in the Kidney, Liver, Bone, Muscle, Spleen,
and Blood.
T represents the amount of lead in all other tissues,
organs, and sinks not included in the model. The
inclusion of this conceptual organ allows the
conservation of equilibrium in the whole system.
UR, FE represent the amount of lead respectively in
the urine and feces.
Xi represent the rate constant for the transfer of lead
from organ i to the blood.
^ i represent the rate constant for the transfer of lead
from the blood to organ i.
A1!!, X*f represent respectively, the rate constant for
the transfer of lead from the blood to the urine and
feces.
Rfd represent the rate input of lead to the body from
food and water.
R^d, R1^ represent the rate input of lead to the
blood from food and air, respectively.
BR represent breathing rate.
CA represent concentration of lead in air.
XA represent the fraction of lead from air absorbed
into the blood.
IRn represent the ingestion rate of food type n.
CEn represent the concentration of lead in food type
n.
Xn represent the fraction of lead absorbed into the
blood from food type n.
Relative to a given input and the rate constants Xi, and
X1 j, the model will yield the concentration of lead in the
various organs at any given time.
In matrix form the above system of equations can be
written as
dX = AX + B
dt
(12)
Where: X is the vector of concentration in organs.
A a square matrix of rate constants
B a vector of input rates
If matrix A is known, then the analytical solution to
equation (12) is found in any book on differential
equations (6). The solution is a sum of exponentials of
the form:
X = ^ Cj Zj eKJ-t - A-'B
Where: J is the dimension of the vector X.
K an eigen value of matrix A
Z the corresponding eigen vector
C a constant depending on initial conditions
Other methods of solution for the system are available
through the use of numerical integration routines readily
available on computers.
An experiment on rats was devised to be used in
conjunction with the model described by Equations (1)
to (11). The purpose of the experiment is twofold:
1. to validate the model or suggest modifications.
2. to determine the rate constants of the model, in this
case for rats.
Dr. R. M. Forbes, of the Animal Science Laboratory,
designed and implemented the experiment with his
assistants. In brief, the experiment consisted of 240
adult male albino rats. These rats were divided into six
groups, where each group was fed for a total of eight
weeks a given level of lead. The levels chosen were 0, 20,
40, 80, 160, and 320 ppm lead. Rats on each level were
killed at 0, 1, 2, 4, 8 weeks interval. The remaining rats
were all fed for a total of eight additional weeks on the 0
lead basol, with some being killed at similar time
intervals. Tissues were prepared for analysis by wet
ashing, dry ashing for bones. Lead determination was
made by either atomic absorption or anodic stripping
voltametry (7). For the purposes of the model, six
organs were examined for lead concentration at the time
intervals specified above; the organs are: Bone, Liver,
Muscle, Kidney, Spleen, and Blood.
All the data have been collected as of this date, but
the analysis required to determine the role constants and
validate the model is not yet completed, and, therefore,
no final conclusion can be reached at this stage.
Nevertheless, during the data collection, some
experimentation on the model was made. The approach
taken was to assume certain values for the rate constants
(i.e. X and X1), compile the predicted concentrations,
and compare them with the reported concentrations;
then readjust the rate constants and repeat the process,
until the predicted values were matching, satisfactorily,
the measured concentrations that were available. This
process of calibration was accomplished using CSMP on
an IBM 360/75 of the University of Illinois. The final
tuning of the model, using this trial and error method,
was stopped when the complete data were available.
Regression analysis is being used now.
Figure 3 to Figure 8 show the results of the initial
effort for a level of input of 360 ppm lead. The actual
concentrations of lead over time is plotted for all organs,
together with the concentrations calculated from the
model. All that can be said at this stage, is that the
preliminary results from the model look very promising.
-------
58
CYCLING AND CONTROL OF METALS
ppm
012345678
TIME IN WEEKS
KIDNEY
Figure 3. Predicted and actual concentration of lead.
ppm
7
6
5
4
3
2
1
PREDICTED
ACTUAL
I I I I I I
012345678
TIME IN WEEKS
SPLEEN
Figure 5. Predicted and actual concentration of lead.
ppm
PREDICTED
ACTUAL
I I I I
I
0.7
0.6
0.5
0.4
0.3
0.2
0.1
PREDICTED
ACTUAL
012345678 0
TIME IN WEEKS
BLOOD
Figure 4. Predicted and actual concentration of lead. Figure
1
8
23456
TIME IN WEEKS
MUSCLE
6. Predicted and actual concentration of lead.
-------
LEAD - BIOLOGICAL TRANSPORT
59
ppm
35
30
25
20
15
10
5
PREDICTED
ACTUAL
012345678
TIME IN WEEKS
BONE
Figure 7. Predicted and actual concentration of lead.
p
1.75
1.50
1.25
1.00
0.75
0.50
0.25
C
am
nnrpi i^*v^r*
ACTUAL
/ \ x — ..
/ s x ^~-~-^
.' \ S - ~-i ^ __j
~t/
1 1 1 1 1 1 1 1
112345678
TIME IN WEEKS
LIVER
Figure 8. Predicted and actual concentration of lead.
REFERENCES
1. Report of Committee II on Permissible Dose for
Internal Radiation, Published for the International
Commission on Radiological Protection, Pergamon
Press, 1959.
2. Miller, C. F., The Contamination of Milk by
radionuclides in fall out, Prepared for Office of
Civil Defense, Department of Defense, Washington,
D. C. by Stanford Research Institue, Oct. 1963.
3. Miller, C. F. and S. L. Brown, Models for estimating
the absorbed dose from assimilation of
radionuclides in body organs of humans, Prepared
for Office of Civil Defense, Department of Defense,
Washington, D. C. by Stanford Research Institute,
May 1963.
4. O'Neill, R. V. and D. W. Burke, A Single Systems
Model for DDT and DDE Movement in the Human
Food Chain, Ecological Sciences Division
publication No. 415 ORNL IBP - 71 - 9, Nov.
1971.
S.Goldstein, R. A. and J. W. Elwood, A two
compartment, three parameter model for the
absorption and retention of ingested elements by
animals, Ecology, Vol. 52, No. 5,1971.
6. Braner, F and J. A. Nohel, Ordinary Differential
Equations, W. A. Benjamin Inc., New York, 1967.
7. Environmental Studies Program, Environmental
Pollution by Lead and Other Metals, Progress
Report, University of Illinois, Urbana-Champaign,
April 30,1972.
-------
PANEL DISCUSSION
EFFECTS AND ESTABLISHMENT OF CRITERIA
-------
EFFECTS AND DEVELOPMENT OF CRITERIA
AND THE ESTABLISHMENT OF STANDARDS
H. WISER
Environmental Protection Agency
Washington, D. C.
We are primarily concerned with the effects on man.
The effects on man's welfare, such as the effects on
vegetation, the quality of his waters, beaches, parks, or
quality of the paint finish on his car or home, are of
secondary importance. The people who study effects try
to get quantitative information, as best as possible, on
the level of the pollutant and the effect caused by that
level; this is an extremely difficult thing to do. A lot of
information, look at the upper end of the curve if you
were to plot effects versus level, might be obtained from
mortality statistical tables, or from occupational health
tables. Perhaps a lot of information could be obtained
from studies with large overdoses, or even moderate
doses, using animals in the laboratory or other types of
organisms. Lesser amounts of data are obtained by
studying the effects caused by low doses over longer
periods of time. For example: The effects of
atmospheric pollution due to smoking may not come up
for twenty, thirty, or forty years, if at all. Yet we know
that there are some people who may be affected within a
few years, and once the damage is done it is extremely
critical. The experimenters who look at these subtle
effects really don't have much time. If we look at
genetic effects, there certainly is not much time. It's
hard to accelerate studies like this. We use animals that
have smaller life cycles and continue studies of that sort.
On man himself, we have to try to postulate what will
happen. We get data from children who are sick, and as
in other organisms, the young are more susceptible to
damage by pollutants than the adults. The experimenters
or researchers "home in" on such numbers as parts per
million or per billion. Many of these experiments are
being conducted by epidemiologists where there is a
great deal of statistics involved. When orders of
magnitude are closely studied, the threshold (not j_
threshold) can be selected for protecting man. We are
talking about parts per billion over a range of six orders
of magnitude, say from one part in a thousand to a part
per billion, and if when we are able to "home in" within
a factor of two or three, I think we're doing an excellent
job. When we look at these numbers within the agency,
we try to pick a good trade-off. Now let me back off a
minute. When I say a trade-off I do not mean a
compromise. I mean a practical trade-off. For example,
are we to protect every single individual? If the data
come from statistics, we really can't. We really have no
feel for that. On the other hand, if we know that it is
very economic to have a standard set at a certain level,
because that level is approximately where the polluters
are operating, and this is what man can tolerate, we have
a high degree of confidence that our numbers are right,
even though there are low-level effects and some effects
the level of which we're not quite sure. If you look at
that, that is an easy way out. Then you might say that,
10 percent or five percent or one percent or even one
part in a thousand of our population is really going to be
affected, especially the young. We do try to protect as
much as possible of the population, however, most levels
might be where you're protecting 99.99 percent of the
population if possible. It's true that we do exist in this
environment. It is also true that we don't want to give
up our standard of living or the way we live. For
example, the automobile. None of us is willing to give up
the automobile because of lead pollution, even though
about 50,000 people a year lose their lives in accidents.
We're not willing to make that trade-off. So these are the
things to consider. Now the people who set the
standards start off with what we call a criteria
document, which is a document put together to
represent the total important knowledge on that subject.
When I say important, I mean that the people who have
put these documents together are usually large groups of
people. EPA sometimes does it in-house. We do it with
the National Academy of Science; we'll use other
organizations. We'll use a lot of other consultants. What
really comes out of it is really an academic tone, so to
speak; almost a handbook or encyclopedia of that
particular pollutant, listing what its sources are, what its
61
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62
CYCLING AND CONTROL OF METALS
transport mechanism is, its chemistry, its physics, how it
affects man, how if affects the environment, how it is
measured, perhaps how it may be controlled, or do we
have a control? If we know that something is extremely
harmful we still may not be able to measure it because
such a small amount hurts us. We may not be able to
control it. It may be beyond the technology, yet we
know we do have to protect ourselves; and this
document is what we call a criteria document. It has all
the information in it, as best we know, which has come
from all the knowledgeable people and knowledgeable
sources. When I say total important knowledge, I mean
that we have certainly distilled what is in the literature.
We cannot of course afford to, nor are we interested in,
even though we do read every word or we think the
people who put these together read every piece of
literature, but they certainly do not combine all of it.
They really digest and use the important ones. And they
do come up with recommendations. Finally, looking at
it from many viewpoints, from the viewpoint of the
person who wants to protect the last man, as to how low
a standard should be, to one who is very practical, who
is interested in what the economic cost or risk benefit
trade-offs might be, or as is stated in the new water
legislation, to use the best practical means and later on
the best technological available means perhaps regardless
of cost within reason, of course, and this is how our
standards are set. Let me make a comment about that. I
think we could almost get rid of a great deal of our
pollution. For example, this is not too far-fetched, it is
not economic to use plasma arc and essentially ionize
everything we have. Of course we will still come out
with the basic elements, but we will have gotten rid of
the pollutants in many undesirable forms like pesticides,
or bacteria, or other toxic substances. There are ways of
doing it; of course, we cannot afford that. We do try to
put together standards on a rational basis from many
viewpoints, and when the various people, or people who
have interests in these things, come together, by the way
these documents are standards before they are set, even
are promulgated, the agency as well as other agencies or
other things do hold hearings and all the information is
put together. Finally, it is the responsibility of the
administrator of the EPA to set a standard and then it
becomes law. One of the things I forgot to mention is
that knowing the sources of a given pollutant, we then
have to decide how we ration this. If you want to keep
the ambient air down, and we know all the sources in a
given region, we have to ration that amount of that type
of pollutant among all the sources. That is a tough
decision. With regard to what a man might take in; we
don't just look at what comes in through the water or
through the air, but also what is he taking in through the
food. How much normally exists in his body? How much
does his body retain, and how much does his body take
out? Just because a pollutant level is extremely high in
the body doesn't mean that it has an effect on it. Maybe
it has no el'tect, and we really try to look at the effects.
Then make these trade-offs and then finally come up
with these standards.
-------
EFFECTS AND ESTABLISHMENT OF CRITERIA
T. E. LARSON
Illinois State Water Survey
Urbana, Illinois
Time does not permit a detailed discussion of the
effects of the various parameters, or an enumeration of
numbers recommended as criteria. I should prefer to
discuss and quote the general rationale involved in the
establishment of criteria for sources of water for public
water supplies, because it is important to understand
how the numbers were derived.
CRITERIA
The establishment of criteria represents an attempt to
quantify water quality in terms of its physical, chemical,
biological and aesthetic values. The problem of
establishing criteria lies with the availability of objective
and subjective data.
To the extent that scientific data are available, the
evaluations for the derivation of recommendations may
be overly restrictive and pose an unnecessary economic
burden, or they may provide only a limited protection
from the hazards that they are intended to prevent. If
adequate criteria for recommendations are available, and
the analytical identifications and monitoring procedures
are sound, the fundamentals are then available to
establish effective standards. At this step, political,
social, and economic factors enter into the decision.
QUALITY CRITERIA FOR PUBLIC WATER SUPPLY
SOURCES
Modern water management techniques and a wide
variety of available water treatment processes make
possible the use of raw water of almost any quality to
produce an acceptable public water supply. For this
reason it is both possible and desirable to consider water
management alternatives and treatment procedures in
making recommendations on the quality of raw water to
be used for public supply. Furthermore, these
recommendations must be consistent with the effort and
money it is reasonable to expect an individual, company,
or municipality to expend to produce a potable water
supply. Defining a reasonable effort, including the
treatment process, involves consideration of the present
quality of water, the degree of improvement in raw
water that is attainable within the bounds of natural and
man-made controls on water quality. Therefore, in
evaluating the basis for the recommendations that
follow, the Panel left water management alternatives
open wherever possible, but it did make certain arbitrary
assumptions about the treatment process.
THE DEFINED TREATMENT PROCESS
Surface water supplies characteristically contain
suspended sediment in varying amounts and are subject
to bacterial and viral contamination. Therefore, it was
assumed that the following defined treatment, and no
more, would be given raw surface water by a qualified
operator prior to human consumption:
1. coagulation (less than about 50 milligrams per liter
(mg/1) alum, ferric sulfate, or copperas with alkali or
acid addition as necessary, but without coagulant aids
or activated carbon);
2. sedimentation (six hours or less);
3. rapid sand filtration (three gallons per square foot per
minute or more);
4. disinfection with chlorine (without consideration to
concentration or form of chlorine residual).
The panel recognized that, on one hand, some raw
surface waters will meet current Federal Drinking Water
Standards with no treatment other than disinfection,
and that, on the other hand, almost any water, including
sea water and grossly polluted fresh water, can be made
potable for a price, by treatment processes already
developed. However, the defined treatment outlined
above is considered reasonable in view of both the
generally attainable quality of raw surface waters, and
the protection made imperative by the current practice
of using streams to transport and degrade wastes.
Assumption of the defined treatment process
throughout this report is not meant to deny the
availability, need, or practicality of other water
treatment processes.
Unlike surface waters, ground waters characteristically
contain little or no suspended sediment, and are largely
free and easily protected from bacterial and viral
contamination. See Ground Water Characteristics below
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64
CYCLING AND CONTROL OF METALS
for significant exceptions. Therefore, no defined
treatment is assumed for raw ground water designated
for use as a public supply, although this does not deny
the availability, need, or practicality of treatment.
Ground waters should meet current Federal Drinking
Water Standards in regard to bacteriological
characteristics and content of toxic substances, thus
permitting an acceptable public water supply to be
produced with no treatment, providing natural water
quality is adequate in other respects. Unless specified
otherwise, the water quality recommendations apply to
both surface water and ground water sources.
WATER QUALITY RECOMMENDATIONS
The Panel has defined water quality recommendations
as those limits of characteristics and concentrations of
substances in raw waters that will allow the production
of a safe, clear, potable, aesthetically pleasing and
acceptable public water supply after treatment. In
setting these recommendations, the Panel recognized
that most of the surface water treatment plants,
providing water for domestic use in the United States,
are relatively small. They do not have sophisticated
technical controls, and are operated by individuals
whose training in modern methods varies widely in
extent.
The recommendations of the public water supply
panel should not be construed as latitude to add
substances to waters where the existing quality is
superior to that called for in the recommendations.
Degradation of raw water sources of quality higher than
that specified should be minimized in order to preserve
operational safety factors and economics of treatment.
The Panel considered factors of safety for each of the
toxic substances discussed, but numerical factors of
safety were employed only where data are available on
the known no-effect level or the minimum effect level of
the substances on humans. These factors were selected
on the basis of the degree of hazard and the fraction of
daily intake, of each substance, that can reasonably be
assigned to water.
The recommendations should be regarded as guides in
the control of health hazards, and not as fine lines
between safe and dangerous concentrations. The amount
and length of time, by which figures in the
recommendations may be exceeded without injury to
health, depends upon the nature of the contaminant,
whether iugh concentrations, even for short periods,
produce acute poisoning, whether the effects are
cumulative, how frequently high concentrations occur,
and how long they last. All these factors must be
considered in deciding whether a hazardous situation
exists.
Although some of the toxic substances considered are
known to be associated with suspended solids, in raw
surface waters, which might be removed, to some extent,
by the defined treatment process, the degree of removal
of the various soluble toxic substances is not generally
known; and even if known, it could not be assured under
present treatment practices. Therefore, in the interest of
safety, it was usually assumed that there is no removal of
toxic substances as a result of the defined treatment
process.
Substances not included in the report are not
necessarily innocuous in public water supply sources. It
would be impractical to prepare a compendium of all
toxic, deleterious, or otherwise unwelcomed agents,
both organic and inorganic, that may enter a surface
water supply. In specific locations it may become
necessary to determine the presence of substances not
considered in the report, particularly where local
pollution indicates that the substance may have a
significant effect on the beneficial use of water for
public supplies.
In summary: the recommendations in the report for
raw water quality for public supplies assure that the
water will be potable, for surface water, with the defined
treatment process; for ground water, with no treatment
whatsoever. For waters zoned for public supply, but not
meeting the recommendations in all respects, the
recommendations can be considered a minimum target
toward which efforts at upgrading the quality should be
directed. In some instances, the natural quality of raw
water may make meeting certain recommendations
impractical, or even impossible. For constituents for
which this is the case, and where health is not a factor,
the natural quality of the water can be considered a
reasonable target toward which to work, although
determination of natural quality may require
considerable effort, expense, and time. Wherever water
quality is found superior to that described in the
recommendations, efforts should be made to minimize
its degradation.
GROUND WATER CHARACTERISTICS
Development of water quality recommendations for
ground water bodies must provide for the significant
differences between surface water and ground water.
Ground water is generally not confined in a discrete
channel. Its quality can be measured, in any detail, with
difficulty and at great expense. A thorough knowledge
of the hydrologic characteristics of the ground water
body may be obtained after extensive study. Movement
of ground water can be extremely slow; so that pollution
occurring today in one part of an aquifer may not
become evident at a point of withdrawal for several,
tens, hundreds, or even thousands of years.
Wastes mix differently with ground waters than they
do with surface waters. Where allowance for a mixing
zone, in the immediate vicinity of a waste outfall, can be
provided for in surface water standards, under the
assumption that mixing is complete within a short
distance downstream, dispersion of waste, in a ground
water body, may not be complete for many years. The
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PANEL DISCUSSION
65
long retention time will facilitate bacterial or chemical
reactions with aquifer components that result in removal
or decomposition of a pollutant to the point where it no
longer degrades the aquifer. Because these reactions are
imperfectly known and cannot be predicted at the
present time, it is necessary to monitor the movement of
waste in a ground water body from the point of
introduction outward. Unlike bodies of surface water,
bodies of ground water cannot be monitored adequately
by sampling at the point of use.
Inadvertent or careless contamination of fresh ground
water bodies is occurring today from the leaching of
accumulated salts from irrigation, animal feed lots, road
salt, agricultural fertilizers, and dumps and landfills; or
from leakage of sewerlines in sandy soil, septic tank
effluents, petroleum product pipelines, and chemical
waste lagoons. Another source of contamination is the
upward movement of saline water in improperly plugged
wells and drill holes, or as the result of excessive
withdrawal of ground water. Deep-well injection causes
intentional introduction of wastes into saline ground
water bodies.
Because of their common use as private water supplies
in rural areas, all geologically unconfined, water-table,
aquifers could be placed in a classification comparable to
that for raw surface waters used for public water
supplies. Even though not all waters in these aquifers are
suitable for use without treatment, such classification
could be used to prohibit introduction of wastes into
them. This would restrict the use of landfills and other
surface disposal practices. Limited use of the
unsaturated zone for disposal of wastes would still be
acceptable, provided that decomposition of organic
wastes and sorption of pollutants, in the zone of
aeration, were essentially complete before the drain
water reached the water table. Bodies of artesian ground
water, in present use as public and private supplies,
could be similarly classified wherever their natural
source of recharge was sufficient to sustain the current
yield and quality.
Disposal of wastes, in either of the above types of
aquifers, could be expressly forbidden on the basis of
their classification as public water supplies.
Furthermore, before disposal of wastes to the soil or
bedrock adjacent to aquifers used or usable for public
supply were permitted, it could be required that a
geologic reconnaissance be made to determine possible
effects on ground water quality.
Water quality recommendations, for raw ground
waters to be used for public water supplies, are more
restrictive than water quality recommendations, for raw
surface water sources, because of the assumption that no
treatment will be given to the ground waters. The
distinction between surface and ground waters is,
therefore, necessary for proper application of the
recommendations. In certain cases, this distinction is not
easily made. For example, collector wells in shallow river
valley alluvium, wells tapping cavernous limestone, and
certain other types of shallow wells may intercept water
only a short distance away, or after only a brief period
of travel, from the point at which it was surface water.
Springs used as raw water sources present a similar
problem. Choice of the appropriate water quality
recommendations, to apply to such raw water sources,
should be based on the individual situation.
WATER MANAGEMENT CONSIDERATIONS
The purpose of establishing water quality
recommendations and, subsequently, establishing water
quality standards is to protect the nation's water from
degradation, and provide a basis for improvement of
their quality. These actions should not preclude the use
of good water management practices. For example, it
may be possible to supplement streamflow with ground
water pumped from wells, or to replace ground water
removed from an aquifer with surface water through
artificial recharge. These other sources of water may be
of lower quality than the water originally present, but it
should remain a management choice whether this lower
quality is preferable to no water at all. In arid parts of
the nation, water management practices of this sort have
been applied for many years to partially offset the
effects of mining of ground water. Example, its
withdrawal at a faster rate than it can be recharged
naturally.
It is possible, by merely removing ground water from
the aquifer, to degrade the quality of that remaining, by
inducing recharge from a surface or ground water body
of lesser quality. It does not seem reasonable to forbid
the use of the high-quality water that is there because of
this potential degradation. Of what value is it if it cannot
be used?
It would appear, that degradation by choice might be
an alternative under certain conditions and within
certain limits. This type of degradation is not
comparable to that resulting from disposal of wastes in
the water body. It is simply the price exacted for using
the water. In the case of mining without artificial
recharge, the philosophy involved is the same as that
applied to the mining of other nonrenewable resources
such as metal ores or fossil fuels. Because considerations
of recreation and aesthetics, and the maintenance of fish
and wildlife are generally not involved in this kind of
management situation, it is reasonable that water quality
standards should provide for the mining and artificial
recharge of bodies of ground water zoned for public
supply. As in any water management program, it would
be necessary to understand the hydrologic system and to
monitor changes induced in the system by management
activities.
Preservation of water management choices can be
protected by water use classification. Classification of
surface waters has not been based solely on the fact that
those waters are being used for public supply at the
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66 CYCLING AND CONTROL OF METALS
present time. Presumably, it has been based on the in use for that purpose. Conversely, failure to zone a
decision that the body of water in question should be body of water for public supply would not necessarily
usable for public supply with no more than the routine preclude its use for that purpose. Selective zoning could
forms of water treatment, whether or not it is presently thus be used to assure desirable water management.
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HUMAN STUDIES LABORATORY
G. J. LOVE
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina
Within the U.S. Environmental Protection Agency, the
Human Studies Laboratory (HSL) has been given
primary responsibility for developing the health
intelligence necessary for the establishment of adequate
environmental quality standards. This task is
complicated by the fact that little information is
available concerning the following topics:
1. What are the toxic materials now present in the
environment?
2. What is the potential for newly developed materials
being toxic, particularly as a result of long-term
exposure to low levels?
3. If a screening procedure suggests a high toxicity
potential for particular materials, how do we
determine levels of environmental exposure? (This
may not be HSL's responsibility, but the knowledge is
vital if any kind of priorities for studies are to be
established.)
4. What is the significance of the various formulations of
a toxic substance, example, how do the physical and
chemical properties of the various compounds relate
to its toxicity?
Assuming that estimates of these factors can be
developed, additional concern must be given to
measurements of total intake and routes of intake as
well as to absorption, distribution, storage and excretion
of the individual material.
Finally, the Human Studies Laboratory must be
concerned with the entire biologic spectrum of response
that may occur as a result of exposure. This is illustrated
by the following figure.
SIGNIFICANT
HEALTH
EFFECT
J.
L
MORBIDITY
\
/ PHYSIOLOGIC
/ CHANGES
/ HERALDING ILLNESS
/ PHYSIOLOGIC CHANGE \
/ Of ^
/ UNCERTAIN SIGNIFICANCE
r
INCREASED POLLUTANT BURDEN
\
PROPORTION OF
-* *-
POPULATION AFFECTED
Responding to these needs is the goal of the EPA,
Human Studies Program. Obviously, there are many
difficulties and many problems not yet solved. At
present we are forced to rely heavily on occupational
data that for several reasons are less than satisfactory.
However, since the need and the obligation to protect
human health surmounts all other responsibilities, we
utilize the best data available to develop
recommendations when they are needed, and
recommendations for whatever action appears to be
necessary to assure adequate protection for even the
more susceptible or sensitive segments of our
population.
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SIGNIFICANT EFFECT OF POLLUTANTS
J. F. COLE
International Lead Zinc Research Organization, Inc.
New York, N. Y.
One of the problems with which we must wrestle in
the environmental field, and especially in the area of
criteria establishment, is to determine what is a
significant effect of a given pollutant. If we can provide
definition of a significant effect, then the overall
problem is reduced to monitoring and analysis. I don't
mean to minimize the difficulties inherent in these areas
but, we may bring our technical expertise to bear on
these. Determination of what constitutes a significant
effect involves philosophy and judgment. Our technical
skills won't do us much good in these areas.
What is a significant effect? This is a question of much
controversy. Some would have us believe that a
significant effect is any measurable change in man or the
environment, while others hold that an effect is not
significant unless it produces frank illness in man or
measurable harm to the environment. It seems clear that
the effects on which criteria are established, and upon
which standards are eventually set, must be somewhere
in between these two extremes. Admittedly, the ground
in between is sometimes extremely broad, and it takes
wisdom and courage to define criteria and to set
standards in this very grey area; yet this is what must be
done. It takes wisdom to decide what constitutes
evidence of a significant effect. It takes courage to
withstand the pressures of those who want no-risk
criteria and standards, and those who would have us
reject even minimal safety factors.
Those who advocate the no-risk concept often use the
argument that any substance must be shown to have no
ill effects before it may be introduced into our
environment, and environmental contaminants, about
which such information is not available, which are
already present must be eliminated or banned. I reject
this concept because one can never prove the negative;
therefore, it is impractical. Further, widespread
acceptance of this concept would cripple our economy
and stifle new developments. Unfortunately, there is a
disturbing tendency toward this point of view, and some
of the recent stringent regulatory action are a result of
this philosophy. I cite the recent requirements, of the
Clean Air Act, for a 90 percent reduction over 1970
levels of NOX, CO and unburned hydrocarbons in
automobile exhaust, and the talk about zero discharge in
the new water pollution act. It is doubtful that there is
scientific justification to support those, and other
extremely stringent standards; the costs are absolutely
awesom.
If we reject the no-risk concept, we must create
guidelines for acceptable safety factors. This is no easy
matter, but I think before we base a criteria on an effect,
we must ask at least two questions:
1. Is the effect in question a detrimental one? Some
effects which are attributed to environmental stresses
can be classed as compensatory responses, but may be
of no known detriment to health. The inhibitory
effect of lead on erythrocytic-ALA dehydrase may be
an example of this type of an effect.
2. What are the trade-offs? The safest approach is to use
the most sensitive effect as a criterion. However, we
must take into consideration the economic costs of
controlling to very stringent low levies. We must also
be concerned about potential substitutes which may
result in environmental problems of even greater
magnitude. An example here is the elimination of lead
from gasoline, wherein, the costs may be exorbitant in
terms of higher gasoline prices, lowered fuel economy,
depletion of petroleum reserves, and the possible
increase of aromatic hydrocarbons into the air.
I recommend that we base criteria on known harmful
effects, and establish our safety factors with full
knowledge and consideration of the economic and
environmental disruption which we may cause by
over-zealous action.
In the field of trace metals, and with other
environmental contaminants, it is extremely important
that environmental effects research, both under
industrial and governmental sponsorship, continue.
Providing both governmental and industrial funding
assures a balanced interpretation of data. Further action
on pollutants must then be taken, based on these data,
and the answer to the two questions: Is the effect
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70 CYCLING AND CONTROL OF METALS
harmful? Will it do more harm than good to replace or more deliberate approach to criteria establishment and
eliminate the pollutant? standard selling, but an approach which at the same
If scientists address themselves to these questions and time, will protect our society and our environment with
provide answers and interpretation, then we may see a a minimum disruption to our economic well being.
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STATEMENT ON ESTABLISHMENT OF CRITERIA
FOR METALS IN FOODS
C. F. JELINEK
U.S. Department of Health, Education, and Welfare
Washington, D. C.
In the Bureau of Foods program, to assess the hazards
of toxic elements in foods, we must be governed by the
fact that man experiences a finite level of intake of all
the elements in the earth's crust, as demonstrated by
their presence in the human tissue (1). We are dealing
with materials that enter food through natural geologic
causes as well as man's activity. Our problem is to
determine what level of exposure, from food, is
consistent with safety. In the process of determining an
acceptable level of exposure to a metal from any given
food, it is essential to define the level of unavoidable
background exposure from all environmental sources,
such as food, water and air. This is in marked contrast to
criteria usually employed with a new substance
proposed for addition to food or water, where sources of
exposure can be better controlled.
In our approach to this problem, we feel we must,
determine the overall level of occurrence of the toxic
elements in food in order to obtain a good indication of
the natural background level in food, and find out
whether specific components of the food supply contain
unusually high levels, so that potential problems are
readily identified. In determining levels of exposure
compatible with health, we must take into account all
sources and routes of exposure. For example, although
mercury exposure is almost entirely through the diet,
significant exposure to lead can occur from air, water,
industrial exposure and pica.
In regards to occurrence of a given metal in our food
supply, we must not only obtain data on the general
level in the total food supply, but also develop
information on the frequency distribution in the various
food classes of the diet and on food consumption
patterns. Our establishment of mercury guidelines of 0.5
ppm in fish was simplified by the fact that they could be
based on methyl mercury toxicity, and on information
concerning fish consumption, since no other significant
environmental exposures occur. For lead, cadmium, and
other elements that may be ubiquitous in the food
supply, the problem of setting acceptable intakes
becomes much more complex. We must not only carry
out surveys of such metals in the principal dietary items,
but must also take into account that consumption
patterns differ with age. For example, the diet of very
young infants is almost exclusively milk.
We must consider the chemicalformandbioavailability
of the metal concerned. Well known effects along these
lines are the increased toxicity and bioavailability of
methyl mercury, and that the form in which arsenic
exists in shrimp is essentially physiologically inactive.
I would now like to bring you up to date on our
surveillance activities on toxic metals in the food supply.
Our general philosophy is to develop a full picture of the
occurrence of the metals of interest in food before
setting guidelines, unless a hot spot occurs, in which case
a specific guideline will be set for this particular
situation, based on the best information at hand
concerning exposure, bioavailability and toxicity.
For example, when it became obvious to us that
dangerous amounts of lead and cadmium could be
leached from ceramic ware, because of improper firing,
we established interim guidelines for leachable amounts
of these metals, and have continued carrying out an
active monitoring program on these items, especially of
imports, which have been the bad actors.
In determining the overall level of occurrence, of a
contaminant in the food supply, we conduct continuing
surveys on the Total Diet, which is based on
consumption data, developed by the USDA, seven years
ago. We analyze composite samples of 12 different food
classes, and calculate the intake of a given metal based
on the average total consumption of a young male adult,
which is appreciably more than that of the average adult.
The latest information published covers the levels of
arsenic and cadmium in the Total Diet from June, 1968
to April, 1970 (2). The average overall level for both of
these metals in the Total Diet was around 0.02 ppm,
which we do not regard as hazardous. Mercury was
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CYCLING AND CONTROL OF METALS
added to the Total Diet Survey in June, 1970, and
selenium, lead, and zinc were added in June of this year.
We also carry out a special Fish Survey to determine
the levels of contamination in a variety of sea and fresh
water fish. This fiscal year we have mercury, lead, and
cadmium in our Fish Survey, and plan to add at least
selenium, arsenic, and zinc next fiscal year.
We also carry out Surveys in a variety of food types to
obtain a clearer idea of the levels in important foods. I
mentioned to you that the setting of a guideline for
mercury in food was simplified by the fact that it
occurs, in significant amounts, only in fish. Nevertheless,
we continued monitoring different food categories for
mercury to make sure that the situation had not
changed. Perhaps you have seen the recent article in
Science (3), where we reported that the median
concentrations of mercury in a variety of foods varied
from less than 0.001 ppm to 0.014 ppm; all well below
the 0.5 ppm guideline. This year we are carrying out a
similar survey, on cadmium, in a variety of foods.
In carrying out these surveys, we must be sure we use
reliable analytical methods having satisfactory
sensitivity, accuracy and reproducibility. Dr. Haenni, of
the Bureau of Foods, will go into this subject in more
depth tomorrow.
In addition to developing information on the levels of
toxic metals in foods, as described above, we naturally
consider the lexicological properties of the metals.
There has been a great deal of information published on
this subject, which we take into consideration. In
addition, we are conducting active toxicological
evaluations of mercury, lead, and cadmium ourselves.
We are devoting considerable analytical, toxicological,
and inspectional manpower to obtain accurate
information on overall occurrence of the toxic elements
in foods, and, at the same time, maintain an alert for
special trouble spots which may arise. Our overall
ambitions are not small. We plan to move progressively,
from the six metals we are now evaluating to those
which we feel pose less hazard, until we have assessed
about 20 in all.
This is a much bigger program than we can push
through all at once. Our objective has been to use our
resources to concentrate on the most potentially
hazardous metals first; systematically develop necessary
data for guidelines, but at the same time maintain
flexibility to our approach to be able to provide
protection to the consumer when a real problem arises.
REFERENCES
1. Tucker, J., New Scientist and Science Journal, 55,
728,1971.
1. Duggan and Cornelliussen, Pesticides Monitoring
Journal, 5, 331, 1972.
3. Tanner, J. T., D. H. Friedmann, D. N. Lincoln, L. A.
Ford, and M. Jaffel, Science 177,1102,1972.
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BIOMEDICAL RESEARCH IN SUPPORT OF
CRITERIA AND STANDARDS
D. H. K. LEE
National Institute of Environmental Health Sciences
U.S. Department of Health, Education, and Welfare
Research Triangle Park, North Carolina
The development of an environmental standard rests
on the basic assumption that some kind of a
dose-response relationship can be developed for the
environmental agent in question; that a curve can be
envisaged on a graph relating degree of exposure,
quantitatively expressed on the horizontal axis, to
probable effect, quantitatively expressed on the vertical
axis. It is the business of criteria, supporting the
standard, to develop and justify the relationship to be so
expressed.
The assumption is perfectly valid in a conceptual
sense, but considerable difficulties are often experienced
when one tries to apply it to a particular agent. Many
intervening factors determine how much of a particular
agent, whose concentration in the surrounding air, in
drinking water, or in food is known, actually enters into
the body of the exposed person to constitute the actual
dose. Previous speakers have dealt with some of these
determinants, and it is clear that the regulatory agencies
and the technical experts, that they command, have
gotten fairly close to methods of predicting what
persons, exposed to a particular situation, will probably
receive. Our ability to enter the horizontal axis of the
hypothetical dose-response chart is in reasonably good
shape and rapidly improving.
Unfortunately, we are not in nearly such good shape
with regard to the vertical or response axis. It is not
always clear even what should be used as the response.
Easily measured reactions, such as the pulse rate, may be
unaffected, or so influenced by extraneous factors, as to
be unreliable. Sick absences have some built-in
uncertainties. Subjective complaints like headache or
loss of appetite are very hard to quantify. No one wants
to wait for a specific disease to provide a measurable
effect.
Even if we agree upon the response to be used, it is
very clear that people are far from being equal. A highly
susceptible person may react violently to a dose that
passes unnoticed by the average person. Children often
respond more or less readily than their elders. Sex, race,
the physiological state at the moment, co-existent
disease, self-medication, and a host of conditions create
a spectrum of human variability that can be broken
down into arbitrary segments only with some risk of
injustice to the borderline instances. Furthermore, one
can look only indirectly at what goes on in the human
body, and often has to rely on animal experiments
which introduce their own problems.
Our luncheon speaker, Dr. Laitinen, mentioned some
areas of uncertainty about the way in which metallic
substances produce adverse effects and about the
determinants of biomedical action. Had he had more
time I am sure that his list would nave been much
longer. If you will stand with me outside of the system
for a moment, and try to follow a metallic molecule in
its bodily perigrinations, I think you will see what I
mean. If, on coming from the outside, the molecule
enters the lung, it may simply be breathed out again,
stick on the wall of the large airways, pass through into
the blood stream, or be passed for some time from one
macrophage cell to another. Its fate depends upon its
size, attachment to a larger particle, immediate toxicity
for a cell, or just pure chance. Some of the probabilities
are known, but only some, and these fairly grossly. If it
enters the alimentary canal, its chances of absorption
will vary with its valency, its aggregation, the presence of
materials with which it can combine and be removed
from the scene, the health of the alimentary wall,
intestinal motility, etc., etc.
In the bloodstream, after absorption, it may be carried
in solution, be bound with lipid or protein, or enter a
red blood cell. This disposition, in turn, will affect the
ease with which it can pass from the blood to
intercellular fluid and then to tissue cells. Whether it can
pass into the cell will depend upon the state of the cell
membrane, the presence of carriers, and what the metal
itself does to the cell membrane constituents. As pointed
out by Dr. Abdelnour, the concentration in the blood is
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CYCLING AND CONTROL OF METALS
both the result of past exchanges with cells and the
determinant of future exchanges; a very complex set of
balances. Within the cell, the metallic material may
undergo various changes of state; some decreasing its
chance of adverse effects; some enhancing it. Storage
and release from storage in such material as bone, often
treated as a simple, reversible, linear process, is in reality
a very complex set of balances and interactions, subject
to much variation.
Those molecules that, as a result of all the foregoing
balances and exchanges, manage to impinge on a reactive
cell site may produce quite critical events. They may
combine with sulfhydryl groups and change the
permeability, if not, the structure of membranes. They
may enter into and distort enzymic molecules so that
they can no longer bring normal reactants together. Or
they may provide just the metallic atoms that the
enzyme needs for its structure, in which case we would
call them essential metals. They may change the
solubility of some reactants, removing them from
desirable processes. The more one presses the question,
Just why is this metal toxic?, the more uncertain the
answers tend to become. Finally, the process of
excretion involves a triple problem of uncertainty. The
cells of excretory organs are vulnerable just as other
cells; they exercise a special metabolic relationship with
the material being excreted, and they are often exposed
to much higher concentrations of the material than are
other cells.
In the face of all this uncertainty, what is the
standard-setter to do? He clearly cannot sit on his hands
until the research boys make up their minds. If there is
strong presumptive evidence that an agent is harmful he
must set some kind of limit which will protect most, if
not all. of those who may be exposed to it. He can only
make the best judgment that he can on the basis of the
evidence that he has. He, and the public he serves, must
recognize that the ideal is approachable only by stages,
with amendments introduced as better information
becomes available. After all, we have spent 5000 years
getting into this mess; but only 5000 days or so worring
about it. It is a bit much to expect research to give good
answers in 5000 hours. However, the standard-setter can
be certain of one thing; whatever judgment he makes
will be attacked, and evidence to the contrary will be
adduced by those who find the judgment hard to take.
To combat pressures, and to ensure the public of the
best protection that is justifiable at the time one can
recommend just thiee things: (a) that the various
environmental agents be placed in some kind of rank
order as regards importance, severity of effect, number
of people exposed, relation to other exposures,
feasibility of control, etc. (b) that those making the
judgment are permitted to do so according to their
conscience; regardless of the pressures and interests of
those affected, (c) that every opportunity be given,
through resources and conditions of work, to those who
are trying to see toxicologjcal responses and mechanisms
clearly, so that still better judgments can be made in the
future.
-------
SESSION III
CONTROL PROCESSES
Chairman:
C. J. Lyons
Battelle's Columbus Laboratories
-------
TRACE METALS IN EFFLUENTS FROM
METALLURGICAL OPERATIONS
J. B. HALLOWELL, R. H. CHERRY, JR., AND G. R. SMITHSON, JR.
The Columbus Laboratories of the Battelle Memorial Institute
Columbus, Ohio
INTRODUCTION
The purpose of this paper is to list the current
pollution control techniques associated with
metallurgical operations, and to present some examples
of data describing the behavior of trace metals in waste
streams from smelting operations.
The approaches taken to control pollutants in waste
streams in metallurgical operations are shown in the
summary listing in Table 1 of pollution factors and the
methods of control applied to waste gas and water
streams. Two basic, and relatively long-term approaches
to waste streams are modification of processes to
minimize or eliminate the waste stream, and segregation
of waste streams to minimize the volume to be treated,
to allow the use of a specific treatment method, and to
maximize the effectiveness of the treatment. The
modification of processes generally involves the time and
cost associated with research, development, and
equipment changes, while the segregation of waste
streams usually involves alteration of existing plant
facilities.
In cases where lowering of concentrations of specific
impurities is the intent, dilution of waste water with
purer water, or with a different waste water, may
achieve conformance with discharge limitations. In the
case of waste gas streams, dilution, or dispersion may be
achieved by means of tall stacks. The standard methods
of separating suspended solids from liquid waste streams
and particulates from gas streams are listed in Table 1
and include only traditional devices. The term Inorganics
refers to dissolved salts in liquid streams and to
particulates and vaporized materials, such as, mercury, in
gas streams. The term Organics refers to BOD, oil, etc.,
in water, and to hydrocarbons and vapors in gas streams.
TRACE METALS IN ELECTROSTATIC
PRECIPITATORS
The following example of the behavior of trace metals
in gases and dusts is taken from an exercise carried out
TABLE 1 METHODS OF CONTROL
Waste volume
or nature
Process modification
waste stream segregation
Water
Aii
Concentration
Suspended solids
Inorganics
Organics
Mists and aerosols
Dilution
Settling,
coagulation
Wet cyclones
Filtration
Centrifuges
Chemical
oxidation
Reduction
Neutralization
Evaporation
Ion exchange
Electrochemical
methods
Biological
treatment
Skimming
Tall stacks
Long flues
Cyclones
Electrostatic
precipitators
Wet scrubbers
Baghouses
Absorption
Reagent injection
Fabric coatings
Wet scrubber
Solutions
After burners
Catalytic reactors
Electrostatic
precipitators
Filters
at a combined copper-zinc smelting plant (1). The point
of the exercise was the recovery of metal values in a
mixture suitable for use in the existing process
equipment. The data obtained have been analyzed to
obtain insight into the behavior of the trace metals in
the control devices.
A flowsheet, depicting the major features of the
metallurgical operation and the dust control equipment
75
-------
76
CYCLING AND CONTROL OF METALS
ZINC
CONCENTRATES
COPPER
CONCENTRATES
SLAB ZINC
PRODUCT
Figure 1. Flowsheet for Cu-Zn smelting plant.
present before a program of alterations, is shown in
Figure 1. Zinc and copper flotation concentrates were
processed to electrolytic zinc and blister copper
products. The two processes were interrelated by the
transfer of zinc leach residues to the copper operation,
and the transfer of slag-fuming product, ZNO, from the
copper reverberatory furnace slags to the zinc operation.
The alterations made in the dust control systems on
the copper process during the plant revisions are shown
in Figure 2. Initially, the gases from drying kilns,
roasters, and reverberatory furnaces were treated in four
electrostatic precipitator units in series. Converter gases
were treated in a separate precipitator unit. In the
altered arrangement, the roaster gases were treated in
half of the original precipitator capacity, and the
reverberatory gases were treated in the other half of the
precipitator capacity. The reverberatory furnace and
converter gases flowed from their precipitators to a
baghouse for additional dust recovery.
Some of the characteristics of the gas streams and
trace metals in the dusts from this smelting operation are
presented in Table 2. The dryer dusts represent, to a fair
degree, the base composition of the feed to the copper
smelting operations. (Major constituents such as SiOj,
Fe, S, etc., are omitted for the sake of brevity.) It may
be noted that all of the trace metals are more
concentrated, on a percentage basis, in the fume than in
the feed material. Cadmium, lead, and arsenic undergo
much greater degrees of concentration than do the base
metals copper and zinc. The trace metals are
concentrated in the fume differently in the various steps
of copper smelting.
The collection efficiencies of electrostatic
precipitation, for trace metals under the before and after
conditions of the plant alteration, are given in Table 3.
In the initial condition, a combined stream from dryers,
roasters, and reverberatory furnaces was treated with an
overall collection efficiency for particulates of 75
percent. Collection efficiencies for the individual
metallic elements varied from 40 percent, for cadmium,
to 93 percent for antimony. When the roaster gas was
segregated to half the original precipitator area, overall
collection efficiency for particulates rose to 98.9
TABLE 2 COPPER-ZINC SMELTER WASTE STREAM CHARACTERISTICS
Metals content, weight % of particulates*
Element
Cu
Zn
Cd
Pb
As
Sb
Ge
Au, oz/ton
Ag, oz/ton
Flow, scf/m
Temp., F
Dust burden.
tons/day
Dryer
dusts
3.3
3.7
0.02
0.6
0.32
0.07
—
0.08
3.42
18,000
325
1
Roaster
dusts
9.3
8.1
1.0
1.5
1.05
0.27
—
0.11
3.03
67,000
350
55
Reverb
dusts
2.7
18.4
0.6
4.9
5.5
1.2
—
0.07
1.89
100,000
1,020
48
Converter
dusts
6.9
28.6
1.14
21.2
2.0
0.71
—
0.12
100,000
800
23
Combined
flowsf
2.8
27.0
0.94
14.1
3.09
0.27
0.001
0.06
330,000
475
38
'Sulfur, silica, iron, etc., not shown.
tAfter electrostatic precipitator.
-------
METALLURGICAL OPERATIONS
77
DRYER —
ROASTER-
REVERB -
CONVERTER
PRECIPITATORS
I I I
BEFORE
DRYER
ROASTER
REVERB
CONVERTER
Jl
AFTER
BAGHOUSE
{•
Figure 2. Smelter waste stream routings.
percent. The ratio of flow rate to precipitator area was
decreased about 40 percent, and gas temperature
decreased about 60 F The general level of collection of
the individual elements increased appropriately except
for cadmium and silver, which were improved, but not
to the levels of the other elements.
A similar tabulation of the before and after data for
the gas stream from the reverberatory furnace, which
was segregated and routed through the other half of the
precipitator, is presented in Table 4. The ratio of flow
rate to precipitator area was about the same as the
original condition, and this particular gas stream was
about 340 F hotter than the combined streams. A
decrease in collection efficiency was observed for total
p articulates and for most of the individual trace
elements'. The numbers indicate some small increases in
collection efficiency for cadmium and antimony, but
these are small and difficult to rationalize in view of the
surrounding data.
One other comparison of trace metal collection
behavior is afforded from the analyses of the converter
dusts. Here, an electrostatic precipitator operating at
800 F showed an overall collection efficiency on total
particulates of 26 percent. The collection efficiencies for
individual elements is shown hi Table 5. In this case,
gold, silver, and copper show collection efficiencies
above the average for total particulates, while the more
TABLE 3 EFFECT OF CONTROL PRACTICE CHANGES ON
SMELTING EFFLUENTS (ROASTER GASES)
Collection efficiencies, %
Element
Cu
Zn
Cd
Pb
As
Sb
Au
Ag
Flow, scf/m
Temp., F
Dust burden,
tons/day, In
Out
Precipitator area
Overall efficiency on
particulates, %
Before
Combined flows
(dryer, roaster, reverb)
86
54
40
65
56
73
82
76
204,000
440
95
Ai
75
After
Roaster gases
99.2
98.4
82.0
96.2
98.5
99.2
98.3
81.4
600,505
380
95
0.62
Ai/2
98.9
-------
78
CYCLING AND CONTROL OF METALS
TABLE 4 EFFECT OF CONTROL PRACTICE
SMELTING
Element
Cu
Zn
Cd
Pb
As
Sb
Au
Ag
Flow, scf/m
Temp., F
Dust burden,
tons/day, In
Out
Precipitator area
Overall efficiency on
particulates,%
EFFLUENTS (REVERB
CHANGES ON
GASES)
Collection efficiences, %
Before
Combined flows
(dryer, roaster , reverb)
86
54
40
65
56
93
82
76
204,000
440
95
-
Ai
75
After
Reverb gases
75.4
29.0
44.8
48.7
50.0
99.1
57.2
35.4
97,000
780
48
18.3
Ai/2
62
(Exit gas to
baghouse)
volatile trace metal elements show collection efficiencies
in the range of 10 to 15 percent.
TABLE 5 COLLECTION EFFICIENCIES ON
CONVERTER GASES AND DUSTS
Element
Cu
Zn
Cd
Pb
As
Sb
Au
Ag
Gas flow, scf/m
Temp., F
Dust burden,
tons/day
Collection
efficiencies, %
85
15
16
13
11
10
94
55
100,000
800
23
Overall efficiency on
particulates, c/c
26
(Exit gas to
baghouse)
The baghouses added to the plant collected dust with
metal contents as shown in Table 6. This dust is, of
course, the feed material for the zinc leaching operation,
with significant values of cadmium and lead.
With the changes described, the plant upgraded
precipitator collection performance from 75 percent to
98.9 percent on the roaster gases, and went from
precipitator performances of 75 percent and 26 percent
on the reverberatory furnace and converter gases to
baghouse treatment and associated higher collection
efficiencies.
TRACE METALS IN COPPER SMELTING
OPERATIONS
As analytical work proceeds, some operations are
developing detailed knowledge of the behavior of trace
metals in their manufacturing processes. Two examples
of the behavior of trace metals in plant operations
follow.
The factors in this example are indicated by the partial
flow diagram in Figure 3. The operation is typical for
the copper industry, consisting of ore flotation
concentration, reverberatory furnace smelting, and
converting. The control device of interest is the cyclone
on the converter. The reported efficiency of this cyclone
for collection of total particulates was 85 percent.
The available analytical data on trace metals in this
system are shown in Table 7. Some of the trace metals
appear in significant quantities only in the latter stages
of processing. In the ore, for example, arsenic is less than
1 ppm and selenium is reported as 50 ppm. The
-------
METALLURGICAL OPERATIONS
79
reverberatory furnace feed is the product from the
flotation concentration process. Analysis of this material
shows that trace metals are concentrating with the
copper, although zinc is the only metal concentrating at
a rate even approaching that of copper. The analyses of
interest are those of the dusts from the converter flue,
the converter cyclone catch, and the dust issuing from
the converter stack. Although the analyses do not allow
a rigorous determination of in-out control effectiveness
ORE •
1
®
CONCENTRATOR
NOTE:
(A) INDICATES ANALYSES
SLAG
BLISTER (A)-*- CYCLONE
COPPER CATCH
Figure 3. Diagram relating analyses to process steps.
for the cyclone, some observations may be made. The
elements arsenic, cadmium, selenium, zinc, and to a
slight extent, chromium appear in higher percentages in
the stack dust than in the dust captured in the flue or
cyclone. Although highly variable in occurrence,
selenium appears to be concentrating in the system in
terms of both the cyclone catch and the stack loss.
CLEANING SMELTER GASES FOR ACID PLANTS
The recent attention paid to mercury has drawn
attention to the trace quantities of mercury found in
some nonferrous metal ores. This trace mercury has been
identified principally in zinc ores where mercury
contents of 20 to 200 ppm are reported. Three zinc
smelters, two in the United States and one overseas, have
been known to have recovered this trace metal in one
TABLE 6 ANALYSES OF BAGHOUSE DUSTS
(COMBINED REVERB AND
CONVERTER DUSTS AFTER ELECTR
ELECTROSTATIC PRECIPITATOR)
Element
Cu
Zn
Cd
Pb
Weight %
1.9
31
1.5
14
way or another. The occasional incidence of mercury in
roaster gases has been known for some years to designers
of sulfuric acid plants for operation on smelter gases.
Lead is a natural choice of materials of construction for
gas cleaning trains. The presence of mercury in smelter
gases results in corrosive attack of the lead.
Sulfuric acid plants being operated at smelters have
established a sequence of gas cleaning steps which
remove trace metals and participates in order to achieve
protection of catalysts and saleable grades of acid purity.
Estimated upper limits for some trace metal and other
constituents in gas streams entering a catalytic sulfuric
acid plant have been approximated in Table 8 (2).
A typical gas cleaning train for smelter gases consists
of a waste heat boiler, a spray or tower scrubber using
weak (30 percent) acid, and always one or more
electrostatic precipitators for removal of particulates and
demisting (Figure 4). A recently installed overseas
facility, for the recovery of mercury from zinc ore
roasting gases, had a similar gas cleaning train with the
addition between waste heat boiler and weak acid
scrubber of a packed tower concentrated acid scrubber
(3). In this scrubber, the mercury, and also the selenium,
in the gas stream were sulfatized and collected in the
acid. The acids from both scrubbers were treated in
clarifiers for solid-liquid separation, the liquids returned
to the roaster and the solids routed to mercury and
selenium recovery operations. Bleeds from the weak-acid
scrubber liquor and demisting precipitators required
separate treatment by sodium sulfide precipitation to
produce solids and a purified acid. It should be noted
that this system accounts for zinc and iron being present
but makes no mention of cadmium or arsenic. The
recovery of mercury is indicated by the data in Table 9.
One of the most common problems, identified in a
1971 survey of smelter waste water problems, was the
disposal of the dilute acid which accumulates in the
weak-acid scrubbers, spray tower sumps, or precipitator
sumps. The liquor is too dilute and too dirty to sell and
very difficult to treat. A typical analysis of this liquor is
-TO MERCURY RECOVERY
Figure 4. Gas cleaning train for smelter gases.
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80
CYCLING AND CONTROL OF METALS
TABLE 7 TRACE METAL ANALYSES IN A COPPER
Reverb
Element Ore f H
I CCU
As <0.0001 0.001
Cd
Cu 0.9 27.4
Se 0.005 0.009
Zn 0.013 0.08
Cr
Mn
Ni 0.006 0.013
V
"Cyclone operates at 500 to 600 F.
TABLE 8 ESTIMATED UPPER LIMITES FOR
CONSTITUENTS IN GASES ENTERING
ACID PLANTS*
r, Approximate limit
Element . , . , , f.3
grains/standard ft
As(asAs203) 0.0005
Pb 0.0005
Hg 0.0001
Se 0.022
Cl 0.0005
F 0.0001
•Reference 2.
TABLE 9 DISTRIBUTION OF MERCURY IN ZINC
MDH7 Df\ A CTTXTf"1 /~\DT7O A TT/~\M *
UKb ROAMING OrLKAllON *
Converter
flue
dust
0.003
0.0001
25
0.0008
0.06
0.002
0.005
0.04
0.006
TABLE
SMELTING OPERATION
Converter Converter
cyclone cyclone
catch stack
0.008-0.010 0.003-0.02
0.002 0.001-0.085
36-72 2.5-15.0
0.02-0.32 <0.0001-2.3
0.06 0.04-4.4
0.001 0.003-0.008
0.004
0.036 0.02
0.005
10 COMPOSITIONS OF ACID PLANT
WATERS, mg/liter
Element , Plant A Plant B
(neutralized)
PH
As
Cd
Cu
Fe
Mn
Ni
Pb
Zn
S04
Se
5.0 1.9
22.1
7.7 0.60
0.06 7.43
7.4
0.7
0.2
0.5 7.23
8.0 7.3
960 1716
0.71
In concentrate
In roaster gas
Gas after Hg removal
Hg in H2 S04
Hg recovery
20-200 ppm
0.0043-0.0348 grain/scf
0.000046-0.000092 grain/scf
0.2-0.4 ppm
99.5%
•Reference 3.
given in Table 10. The Finnish system described above
included a sodium sulfide precipitation treatment to
clean up the final bleed stream and by returning waste
water and gases to the roaster achieved closed loops. No
accounting was shown for such constituents as arsenic,
cadmium, etc.
Thus, the specific solutions to the problems of
disposal of acid plant waters are currently being evolved
by industry. It remains to be seen which of the possible
alternatives mentioned by industry in the prior survey
prove to be most feasible for the various plants. The
alternatives mentioned included: precipitation with S02,
neutralization, evaporation, deep well injection, and
undesignated approaches to recovery.
These examples have shown the types and
concentrations of trace metals encountered in waste
streams from copper and zinc smelting operations. The
first example showed that improved control of emissions
of both total participates and trace metals could be
achieved by improved operating conditions (example,
lower gas flows and temperatures) in existing devices and
the use of additional control devices. All examples
showed that in both waste gas streams and a selected
waste water stream, the more volatile metals (zinc,
cadmium, selenium, mercury, etc.) are the ones most
likely to concentrate and are the most difficult to
control. Further, the applied or planned methods of
control were individually suited to each smelter.
-------
METALLURGICAL OPERATIONS 81
REFERENCE 2. Duecher, W. W., and J. B. West, (editors). The
I.Robertson, D.J., FUtration of Copper Smelter Gases Manufacture of Sulfuric Acid, Reinhold, New
at Hudson Bay Mining and Smelting Company, York, pp. 515, 1959.
Limited, The Canadian Mining and Metallurgical 3- Kangas, J., E. Myholm, and J. Rastas, Smelter Gases
Bulletin, pp. 326-335, May 1960. Yield Mercury, Chemical Engineering, pp. 55-57,
September 6, 1971.
-------
POLLUTION ABATEMENT ESf THE METAL
FINISHING INDUSTRY
J. CIANCIA
U. S. Environmental Protection Agency
Edison, New Jersey
INTRODUCTION
Although there have been some significant advances in
metal finishing waste treatment technology over the
years, the extent of the progress has not been sufficient
to meet the overall needs of the industry. Particularly
today, with public concern and governmental pressure
focussed on toxic pollutants, such as the heavy metals,
chromate, cyanide, and fluoride discharged by metal
finishing facilities, new and improved waste treatment
technology is greatly needed by various segments of the
industry. Moreover, the problem will be compounded as
many municipal sewage plants accepting substantial
amounts of metal finishing wastes upgrade to secondary
treatment under governmental schedules, and the
disposal of metal hydroxide sludges generated in the
conventional treatment approach becomes more difficult
as enforcement agencies intensify solid waste control.
The metal finishing industry in the United States is
comprised of an estimated 20,000 facilities, including
both job shops and captive installations associated with
the automotive, aircraft, electronic, appliance, jewelry
and other industries.
The primary environmental concern of the industry is
water pollution. Waterborne wastes produced in metal
finishing operations contain toxic pollutants, corrosive
substances, oil, grease, surface active agents, organic
solvents, nutrients, and settleable solids.
Metal Finishing Processes
The processing carried out in the industry may be
classified as (a) cleaning for the removal of surface oils,
grease, dirt, buffing compounds, etc. (b) removing
undesirable surfaces such as oxides, rust, and scale by
pickling; defective metal surfaces by stripping; and
portions of metal surfaces by etching, and (c)
electrochemical and chemical processing for surface
coating a basis metal.
Metal surface preparation and cleaning are
accomplished by (a) mechanical finishing activities, (b)
organic solvents and alkaline cleaning solutions, and (c)
pickling solutions. Mechanical operations such as
tumbling, blast cleaning, polishing, or buffing produce
solid impurities. Organic solvents and alkaline cleaning
solutions are used to remove solid particles such as oil,
grease, and dirt from workpieces.
Pickling is used extensively for the removal of scale,
corrosion, and other undesirable surface conditions.
Most pickling operations simply involve solution of the
scale in acids such as sulfuric, hydrochloric, phosphoric,
nitric, and hydrofluoric. Acid pickling on a large scale
occurs in the steel industry, but considerable quantities
of acids are also used in metal finishing facilities. Some
pickling is also carried out with alkaline solutions.
Electroplating solutions are basically either acid or
alkaline baths. Acid plating solutions contain free acid
and heavy metals, usually chromium, nickel, copper, or
zinc. Alkaline plating baths are mainly in the form of
complex cyanide solutions. Some of the more significant
cyanide plating solutions are copper, zinc, and cadmium.
Other important metal finishing operations include
chromate conversion coating processes, anodizing,
phosphate coating processes, stripping, etching, bright
dipping, electro and chemical polishing, plating on
plastics, and the application of organic coatings on
metals.
Sources of Waste
In carrying out metal finishing operations, the
workpieces are immersed in the bath and then lifted out,
resulting in some loss of solution from the bath. The
parts are either suspended from a moveable rack or are
placed within a perforated barrel, depending on the size
and shape of the pieces. Transfer of the parts from tank
to tank may be done manually or automatically by
conveyor. In performing the processing, the workpieces
must be properly cleaned and conditioned before
entering the metal finishing baths. Water rinses are
employed after each treatment to prevent carryover of
-------
84
CYCLING AND CONTROL OF METALS
process solution, referred to as "dragout," into the next
metal finishing operation.
The wastes produced in metal finishing facilities come
mainly from the following sources:
1. The dumping of spent baths used for carrying out the
various processing operations.
2. The rinse waters used to wash off process solution
that has adhered to the surface or was entrapped in
crevices due to the shape of the part.
3. Accidental waste discharges which can occur in
practically every metal finishing operation in the
plant. These wastes are usually significant where
relatively little engineering effort has been directed
toward preventing accidents.
Other sources of waste include plant and equipment
cleanup, entrainment of mists in exhaust ventilation
ducts, regenerants from ion exchange units, and sludges
resulting from deposits in process tanks and the
precipitation of contaminants from wastes.
IN-PLANT WASTE CONTROL
The methods available for the abatement of pollution
may be divided into two general categories: (a) In-plant
control techniques for conserving water and eliminating
all unnecessary wastes, and (b) the installation of
treatment and recovery processes to destroy or remove
toxic and objectionable materials in the effluent.
Before considering treatment or recovery, the waste
problem should be completely defined and, where
feasible, reduced to the maximum extent possible by
in-plant control techniques. In approaching the problem,
a prime goal is to prevent the loss of chemicals into the
wastewater. This will result in both a savings in the
chemicals lost, plus the cost to treat these materials in
the wastewater. Another major objective of in-plant
control is to conserve water and reduce the volume of
the waste, thereby decreasing intake water requirements
as well as the size of the waste treatment equipment. In
recent years, water conservation has been recognized to
be a significant cost factor because of rising water costs,
water scarcity in certain areas, and the increased cost of
sewer rental charges.
In addition, process changes can sometimes be made
to reduce or eliminate pollution without affecting
performance or product quality. Some of the process
changes made in metal finishing facilities to achieve
pollution abatement are (a) the use of low or
noncyanide plating solutions in place of high cyanide
baths, (b) the replacement of phosphate in cleaning
solutions, and (c) the substitution of mechanical
cleaning for chemical treatments such as pickling.
An integral part of all industrial waste surveys that
should not be overlooked is a complete reappraisal of
the metal finishing operations carried out at the plant.
This would involve an evaluation of the technical and
economic features of both the processing and waste
disposal aspects of the problem.
A breakdown of the various in-plant control methods
for reducing contaminant loads and/or waste volume are
shown in Tables 1 to 4. Basically, the reduction of
dragout reduces the waste load; effective rinsing and
water reuse practices conserve water and reduce the
waste volume; and the prevention of spills, leaks, and
other losses reduce the waste load and/or volume.
TABLE 1 REDUCTION OF DRAGOUT
Use of smooth, properly insulated racks designed with
shapes for minimum carryover of process solutions.
Maintenance of racks to keep them in good condition,
free of incidental metal build-up and corrosion.
Proper racking of parts for fast draining.
Scheduling sufficient time above the process tank for
good draining.
Use of splash guards and drip boards for draining the
solution back into the process tank.
Reduction of dragout by air blowoff, or movement of
parts or tumbling of barrels above the process tank.
Use of wetting agents to permit increased drainage of
process solution back into the bath.
TABLE 2 EFFECTIVE RINSING
Proper design of rinse tanks to provide adequate
turbulence and prevent short circuiting of the water.
Use of air agitation in rinse tanks and/or agitation of the
parts.
Use of nonrunning reclaim rinses as the first step to
washing off dragout from parts.
Use of spray or fog rinses.
Use of multiple countercurrent rinsing.
Control of rinsing either manually or automatically by
conductivity or flow of work (running rinse waters
should be shut off when parts are not moving through
the processing line).
WASTE TREATMENT
A variety of techniques are available for treating metal
finishing wastewaters but the generally accepted
procedure involves (a) separation of grease and oil, (b)
oxidative destruction of cyanides, (c) reduction of
chromates, (d) neutralization, (e) separation of the
precipitated metal hydroxides, and (f) disposal of the
sludge.
Other techniques that have achieved significant
application for treating metal finishing wastewaters are
(a) ion exchange to accomplish purification and re-use of
strong baths and rinse waters, (b) the use of evaporation
either alone or in combination with ion exchange to
recover chemicals and purify rinse waters, and (c) the
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METAL FINISHING INDUSTRY
85
TABLE 3 PREVENTION OF ACCIDENTAL AND
OTHER LOSSES
Routine inspections to locate leaks.
Arrangement of all equipment and piping so it is in plain
view and easily accessible.
Installation of float valves or alarm systems to prevent
overflow.
Installation of walls or curbs around metal finishing
baths to retain accidental losses or leaks from the tanks
within enclosed areas.
Eliminating temporary connections in order to prevent
accidental spills and discharging wastes into the wrong
sewer.
Use of storage tanks, sumps, or pits located so as to save
concentrated baths in case of leaks.
Use of above level filling lines in process tanks so
operator can tell whether supply is on or off.
Education of personnel on good housekeeping practices,
particularly in cleanup where every attempt should be
made to minimize water use and salvage materials.
TABLE 4 RE-USE OF WATER
Use of rinse water effluents from some operations in
others with lower rinse water quality requirements.
Use of steam condensate from heating operations as a
source of pure water for solution make-up and rinsing.
Use of recirculating cooling water systems or re-use of
the cooling water for rinsing in certain metal finishing
operations.
Recirculation of washer waters from scrubbers.
Use of high quality water produced by many of the
waste treatment methods for rinsing and/or bath
make-up.
"integrated" or chemical rinse system for treating
dragout prior to water rinsing. In addition, there are also
a large number of metal finishing waste treatment
techniques that have had only a somewhat limited
application or are in various stages of development or
demonstration.
A significant and troublesome problem in metal
finishing wastewater treatment is sludge disposal. The
metal hydroxides precipitated and settled from the
wastewater are gelatinous and very difficult to dewater.
The sludge also contains calcium carbonate and
magnesium hydroxide formed from the hardness in the
water supply, and the dirt that was on the parts or which
resulted from the processing operations. Techniques
available for concentrating or preparing these sludges for
final disposal are thickening, vacuum or pressure
filtration, sludge beds, centrifugation, and drying or
incineration.
TABLE 5 METAL FINISHING WASTE TREATMENT
TECHNOLOGY
Conventional
Alkaline chlorination of cyanide
Chemical reduction of hexavalent chromium to
trivalent form
Precipitation of metals as hydroxides
Ion exchange
Evaporation
Integrated chemical rinsing
Precipitation of hexavalent chromium
Electrolytic
Carbon adsorption
Carbon bed catalytic destruction of cyanide
Reverse osmosis
Electrodialysis
Ion flotation
Kastone process (hydrogen peroxide/formaldehyde
oxidation of cyanide)
Ozone destruction of cyanide
Waste plus waste
Freezing processes
Sulfide precipitation of metals
Reduction of chromium by scrap iron (simultaneous
cementation of copper may also be feasible)
Air pollution problems in the metal finishing industry
result from (a) exhausting toxic and corrosive fumes and
mists from processing baths, (b) solid particles from
mechanical surface preparation activities, and (c) solvent
vapors from cleaners and painting operations. Washers,
packed tower scrubbers, cloth filters, cyclones, and
solvent incinerators are used to prevent these
contaminants from polluting the atmosphere.
The technology for treating metal finishing
wastewaters presently in use or under development and
demonstration is outlined in Table 5.
Conventional Treatment
Chemical destruction by alkaline chlorination is the
commonly used method for removing cyanide from
wastewater. The cyanide can be oxidized to the cyanate
or further to nitrogen gas and carbon dioxide, depending
on the requirements for discharge. Since cyanate
reportedly is only about one-thousandth as toxic as
cyanide, treatment to cyanate may be acceptable to
regulatory agencies in some cases.
The alkaline chlorination process may be carried out
either by adding chlorine gas and an alkaline compound
to the wastewater, or by the use of hypochlorites such as
sodium hypochlorite (NaOCl), calcium hypochlorite
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86
CYCLING AND CONTROL OF METALS
(Ca(OCl)2) or bleaching powder (CaOCl2)-
Alkaline chlorination of cyanide to form cyanates
actually occurs in two stages. The first reaction is
between chlorine and cyanide to form cyanogen
chloride; this reaction is virtually instantaneous at all pH
values. The second reaction involves the hydrolysis of
cyanogen chloride to the cyanate. The rate of hydrolysis
depends primarily on the pH and is relatively rapid at pH
values above 10. At lower pH values, however, sufficient
chlorine must be added to ensure an excess beyond that
needed to oxidize the cyanide to cyanate so that the
liberation of noxious cyanogen chloride is avoided.
The further oxidation of cyanate to nitrogen gas and
carbon dioxide is slow and takes several hours or more at
a pH over 10; however, this can be accomplished in a
relatively short time at a pH below 9.
Wastes also contain heavy metal cyanide complexes in
addition to the sodium cyanide. The alkaline
chlorination process is effective in treating all of the
common metal finishing cyanide complexes with the
exception of nickelocyanides and ferrocyanides. If
sufficient reaction time and excess chlorine are provided,
even the nickelocyanides can be satisfactorily broken
down. Since nickel plating is not carried out in cyanide
solutions, the nickelocyanide complexes may be avoided
by keeping these discharges out of the cyanide drains.
A one- or two-step process may be used to achieve
complete destruction of the cyanide in metal finishing
wastes. A single stage oxidation can be carried out by
maintaining the pH between 8.5 and 9. Excess chlorine
is needed to avoid the liberation of cyanogen chloride.
The two-step process consists of first oxidizing the
cyanide to cyanate at a pH above 10, and then reducing
the pH to a value between 7.0 and 8 for the second stage
oxidation.
The commonly used method for treating
chromium-bearing wastes involves reducing hexavalent
chromium to the trivalent form, which is then amenable
to precipitation as the hydroxide. Normally, the pH of
the waste chromium solution must be lowered since the
optimum pH value for carrying out the reduction is
between 2 and 3. Sulfuric acid is generally used to
reduce the pH of the waste. The reducing agents most
frequently used are sulfur dioxide, sodium bisulfite or
metabisulfite.and ferrous sulfate.
After reducing the chromium and oxidizing the
cyanide, all of the metal finishing wastes are usually
combined and treated to precipitate the various heavy
metals by adjusting the pH of the mixed effluent
to a value between 8 and 8.5.
A batchwise or continuous operation may be
employed for alkaline chlorination or chromium
reduction. Batch systems are mainly suited for treating
wastes from small and medium size metal finishing
plants. The recommended practice for batchwise
treatment is to have duplicate tankage. With two tanks,
the wastes are collected in one while treatment is
provided in the other. Continuous treatment is more
practical for plants handling large volumes of wastes
containing relatively low concentrations of
contaminants. With continuous treatment, the size of
the tankage is substantially reduced compared with that
needed for batch operation, but provision must be made
for handling process solutions that are discharged at
intervals. Continuous treatment requires the use of
automatic oxidation-reduction potential and pH
controllers, both of which are also utilized in some cases
for batch treatment.
Ion Exchange
Using ion exchange waste treatment systems in the
metal finishing field is an accepted practice for certain
types of effluents. Ion exchange is also used to a limited
extent to treat a variety of other metal finishing wastes.
There are two basic applications of ion exchange for
treating metal finishing wastes.
1. To purify the solutionfor re-use, remove heavy metal
contamination from spent processing baths and
reclaim or still rinses.
2. Demineralize individual or mixed flowing rinses and
concentrate the dragout for chemical treatment or
recovery to obtain a high quality water for re-use.
Ion exchange is widely used in the treatment of
chromic acid process baths and rinses, and mixed rinse
waters. A large number of commercial installations use
this process.
Chromic acid plating, copper stripping, and aluminum
anodizing operations are all adversely affected by a
buildup of metallic contaminants in the processing bath.
When the metallic impurities reach a certain level, it
becomes necessary to replace either a portion or the
entire bath with chromic acid. The problem of disposing
of these baths may be overcome by passing the solution
through a cation exchange unit operating on the
hydrogen cycle as illustrated in Figure 1. The metal
cations are removed from the bath and exchanged for
hydrogen ions, thus reforming the chromic acid.
Although chromic acid anodizing solutions can be
RAW WATER
TO WASTE
Figure 1. Cation exchange unit for chromic acid recovery.
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METAL FINISHING INDUSTRY
87
treated directly, chromic acid plating and copper
stripping solutions must be diluted and subsequently
concentrated after ion exchange treatment. The high
chromic acid concentration in these baths prevents
effective removal of the metallic impurities and causes
oxidative degradation of the resin. Highly crosslinked
and macroreticular resins are used to treat chromic
acid solutions due to their ability to withstand oxidizing
conditions.
Ion exchange is also applied commercially to
reconstitute other processing baths including sodium
dichromate passivating or chromatizing solutions,
phosphoric acid solutions used to pickle steel or bright
finish aluminum, and acetic acid solutions used to pickle
magnesium.
Metal finishing rinse waters are treated by ion
exchange for (a) pollution control, (b) water re-use, and
(c) chemical recovery or concentration. A hydrogen
cation and hydroxyl anion exchange column are used to
demineralize the rinse water. Where it is feasible to
segregate the chromic acid, cyanide, and other rinses,
metal may be recovered by treating the individual rinse
waters. For example, when treating chromic acid rinse
waters, the sodium chromate regenerant from the anion
exchanger can be passed through the hydrogen cation
exchanger to reform chromic acid. When treating nickel
plating rinse waters, the sulfuric acid regenerant
discharged from the cation exchanger is a relatively
concentrated nickel sulfate solution. When treating
mixed rinse waters, the contaminants are concentrated
to very small volumes in the regenerant solutions, which
are then easily and effectively treated by conventional
chemical practice.
When treating mixed rinse waters, cyanide
contaminants pose some problems and require special
consideration. Most serious is the poisoning of the anion
resin by the adsorption of tightly held cyanide
complexes that are difficult to regenerate off the
exchanger bed. Conventional demineralization has
shown little or no poisoning effects if the cyanide level is
low. Poisoning of the anion resin will occur when the
cyanide exceeds a certain level, depending on the
contaminants present. A two-stage regeneration
procedure and a three-bed system consisting of a strong
acidic, weakly basic, and strongly basic exchanger permit
effective treatment of cyanide rinse waters.
The use of ion exchange is a common practice for
recovering the precious metals from rinse waters.
Although the tightly held anionic metal complexes
cannot be eluted from the exchanger, the high price of
gold, platinum, and other precious metals makes
incineration of the resin a practical recovery technique.
Evaporation
Evaporative recovery of processing chemicals from
rinse waters has become an established method for
controlling pollution in the metal finishing industry.
This approach, however, has found only limited
application. To be economical, it is generally necessary
to apply evaporation to relatively concentrated rinses,
such as those produced in still or reclaim tanks and those
from countercurrent rinsing. The technique is attractive
in operations where the amount of dragout is large and
waste flows are small. Another important factor is the
cost of the processing chemicals to be recovered. The
evaporative technique requires segregation of the wastes
by compatible types and the use of various means for
excluding or removing impurities.
Evaporative recovery concentrates the chemical
dragout in the rinse water to bath strength and returns
this concentrated solution to the process tanks. The
evaporated water is re-used in the rinse system, thereby
evaporated water is reused in the rinse system, thereby
providing a high quality water for rinsing and minimizing
the water intake to the facility.
In metal finishing systems, dragout naturally purges
baths of any contaminants resulting from the processing
operation. Buildup of impurities in evaporative recovery
operations may be prevented by the incorporation of
techniques such as ion exchange, precipitation, and
activated carbon treatment.
In closed-loop operation (Figure 2), the system is
designed to recover 100 percent of the processing
chemicals lost in the dragout for re-use in the metal
finishing operation. No external rinse water is added
except that required to replace the loss from
atmospheric evaporation. The only chemicals supplied to
the metal finishing bath are those needed to replace
what is actually deposited on parts and to replace that
lost by spillage or accidentally. Although total
closed-loop control represents an idealized system, it has
been closely approximated in many installations.
PLATING TANK
RINSE TANKS
Figure 2. Closed-loop evaporative recovery system.
Often, the favorable economics of closed-loop
evaporative recovery does not apply because a processing
line has an insufficient number of countercurrent rinse
tanks. Generally, at least three rinse tanks are needed to
make evaporative recovery of dragout effective and
economical. The number of rinse tanks determines the
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88
CYCLING AND CONTROL OF METALS
amount of steam required for evaporation, which is the
largest cost for recovery.
When a layout of a metal finishing facility does not
meet the conditions for a closed evaporator loop, a
partial recovery system referred to as open-loop
evaporation may still be attractive. In this operation, the
water from the first rinse tank following the metal
finishing bath is circulated through the evaporator. The
concentrated solution is returned to the processing tank
and the evaporated water is re-used in rinsing. A second
rinse tank is furnished with a separate supply of water
which, after rinsing, is discharged to waste. This rinse
water effluent contains only a very small portion of the
"dragout" because the bulk of the solution carried out
of the bath enters the first rinse tank and is recovered in
the evaporative system. The small fraction of dragout
solution entering the second rinse tank can be treated by
some method other than evaporation before sending it
to the sewer.
Integrated Treatment
The integrated system has gained considerable
acceptance in the United States in recent years and is
now an established method for treating process solutions
dragged out of metal finishing baths. The basic concept
is segregation and treatment of the waste at the source.
Treatment is accomplished by integrating a chemical
washing operation as the first step in the rinsing
sequence. Chemical washing involves simultaneous
removal and treatment of the film of processing solution
adhering to the parts removed from the metal finishing
bath.
The integrated system incorporates a chemical wash
tank immediately following the metal finishing
operation before the part enters the water rinsing
sequence. In some cases, the chemical washing operation
may follow a reclaim still rinse tank. The chemical
solution is continuously recirculated through the wash
tank and a larger reservoir tank as shown in Figure 3. In
the wash tank, the treatment solution both physically
removes the dragout and at the same time chemically
reacts with the contaminants. The reservoir tank is a
buffering component in the system for neutralizing
shock loadings caused by sudden and irregular changes in
the quantity of process solution dragged into the wash
tank. It also serves as a clarifier for settling out the
insoluble metal oxide and hydroxides formed in the first
stage of the reaction, as well as a retention tank to
provide adequate time for the desired chemical
reactions, such as the oxidation of cyanides or the
reduction of chromates. Several wash tanks treating
similar types of dragout solution can be served by a
common reservoir tank. As an example, the same
chemical wash may be used after various cyanide plating
or processing operations or after chromate conversion
coating operations involving different basic metals.
Since the chemical rinse solution is continuously
recirculated and not wasted in the integrated system, a
much higher concentration of chemicals can be used
than is needed to react with the dragout during the time
the workpieces are washed in the treatment solution.
V
PL/I
VUKf, 1 Kt
\ VCL
iTING TANK
i
p
i
T
"] L
REATMENT
w
w*
AlbK
L
T
—
kTER RINSE
WASH ,
(7)PUMP
! SEV
YER
PUMP
CHLORINATOR
OR
HYPOCHLORITE
FEEDER
PUMP
SETTLING TANK
AND RESERVOIR
CAUSTIC
SOLUTION
Figure 3. Integrated waste treatment system for
cyanide plating effluents.
The integrated system produces relatively high density
sludges compared with conventional chemical treatment.
In addition, a substantial portion of the freshwater rinse
may be re-used since there is no direct addition of
treatment chemicals and the carryover from the
chemical wash tank is relatively dilute and nontoxic.
Over a period of time, harmless waste treatment
reaction products, such as sodium chloride, sodium
carbonate, and sodium sulfate, slowly build up in the
chemical wash solution. No problems are normally
encountered, however, because solution is dumped
infrequently and does not contain any toxic materials.
Precipitation of Hexavalent Chromium
Hexavalent chromium also may be directly removed
from metal finishing wastewaters by precipitation as an
insoluble salt of chromic acid. The treatment method
generally involves the use of barium compounds for the
precipitation of insoluble barium chromate.
Rigid chemical control is necessary in carrying out the
operation to ensure the addition of the correct amount
of barium chloride or other compound because of the
generally toxic nature of barium salts. In addition, the
sludges produced in the process are toxic and may
present some disposal problems. Direct precipitation of
chromium has only been applied to a very limited
extent.
Electrolytic Treatment
For strong baths, the electrolytic decomposition of
cyanide solutions is economically feasible. Spent plating
solutions, strip baths, and cyanide dips fall into this
category. The technique is useful for reducing
concentrated solutions to a point where a secondary
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METAL FINISHING INDUSTRY
89
treatment may be employed to remove the remaining
cyanide satisfactorily.
Electrochemical treatment of metal finishing rinse
wastes has not been practical because of the low
conductivity of these effluents. However, a new
electrolytic processing technique has been introduced
that uses a bed of carbon particles between the
electrodes to overcome the high resistance of the rinse
waters. The system is designed to treat either cyanide or
chromate rinse waters.
The individual particles that make up the bed are said
to exhibit bipolar properties under an applied D.C.
current. Each particle has an anode portion at which
oxidation can occur and a cathode portion at which
reduction can take place.
In treating cyanide rinse waters, the cyanide is
oxidized to nitrogen and carbon dioxide, and the metal
ions are both electro-deposited at the cathode sites and
precipitated as the oxide or hydroxide at the anode
sites. In some cases, caustic may have to be added to the
effluent for complete precipitation of the heavy metals.
The treatment of chromium-bearing rinse waters involves
a reduction of the hexavalent chromium to the trivalent
form at the cathode sites but no precipitation will occur
in the beds because of the low pH of the waste. The
trivalent chromium and other heavy metals are
subsequently precipitated by the addition of alkali.
A number of plants are employing the new electrolytic
approach to treat cyanide and chromium-bearing metal
finishing rinse waters.
Carbon Adsorption
A recently completed laboratory and pilot plant study
has resulted hi the development of an activated carbon
adsorption process for treating chrome or cyanide rinse
waters from metal finishing shops. Although the
technical feasibility of the process has been established,
further study and refinement of the stripping operations
are needed as the carbon bed experienced a loss of
chromate capacity and required successively longer
periods for eluting the cyanide over a somewhat limited
number of treatment cycles.
Carbon Bed Catalytic Destruction of Cyanide
A new system that uses a granular activated carbon
bed to catalytically destroy cyanide has recently moved
out of the development and demonstration stage into
commercial application. The process is designed to
continuously oxidize cyanide to carbonates and nitrogen
compounds by adding a copper catalyst and air to the
raw waste and then passing the solution through the
carbon column. The presence of copper ions results in
the formation of copper cyanide complexes that are
adsorbed to a much greater extent than cyanide,
permitting higher flow rates through the column. The
copper also aids in cyanide oxidation and accelerates
cyanate hydrolysis to end products that combine with
the cupric ion to form precipitates of copper carbonate
and copper hydroxide - amine compounds that remain
in the carbon bed. After some period of time, the
carbon bed either must be replaced or the copper
precipitates removed by dissolution with acid.
Membrane Processes
The use of reverse osmosis and electrodialysis as
methods for treating metal finishing rinse waters is in the
development,demonstration, and early application stage.
These membrane techniques accomplish pollution abate-
ment by (a) purifying the rinse water for re-use, and (b)
concentrating the chemicals for return to the bath or for
convenient subsequent treatment or disposal.
Electrodialysis involves the transport of ionic species
through membranes by the application of a D.C. current.
Compartments forme'd by a cation and anion membrane
are arranged in a stack configuration between electrodes.
As the rinse water flows through every other
compartment, the cation exchange membrane permits
the passage of cations and rejects anions, while the anion
membrane allows the passage of anions and rejects
cations, thus purifying the rinse water while forming a
concentrate in the adjacent compartments.
In reverse osmosis, pressure is used to force pure water
through the membrane while the chemicals are rejected
and concentrate in the rinsewater. Reverse osmosis
equipment is available in plate-and-frame, tubular,
spiral-wound, and hollow fiber types.
Along with the application of membrane systems, an
important part of the investigations underway involves a
continuing search for the most appropriate membranes
to treat the various types of rinsewaters. The
development of membranes with improved properties
will have an important bearing on the success and
acceptance that reverse osmosis and electrodialysis
receive in the metal finishing industry.
Ion Flotation
The use of ion flotation for treating metal finishing
rinse waters is in the early development stage. The
technique involves the use of organic collectors having
surface active properties and an inorganic group that
ionizes in aqueous solutions. The contaminant ions such
as chromate or complex cyanides are removed from the
solution by the collector that attaches to small rising air
bubbles that form a froth at the surface.
Hydrogen Peroxide/Formaldehyde Destruction of
Cyanide
A new process referred to as "Kastone" uses a
proprietary peroxygen compound in the presence of
formaldehyde to oxidize cyanide to cyanate in
rinsewaters from zinc or cadmium metal finishing
operations. During the treatment, which is designed for
batchwise operation, the zinc, and/or cadmium, or both
precipitate and are easily removed by filtration. The
major components in the rinse water after treatment are
the cyanate ion, ammonia, and glycolic acid amide. This
-------
90
CYCLING AND CONTROL OF METALS
approach has been finding some acceptance by the
industry, particularly in small metal finishing shops
discharging to municipal sewers.
Ozone Destruction of Cyanide
Ozone is a suitable oxidant for cyanide, with the final
reaction product being substantially cyanate. The
oxidation of cyanide to cyanate by ozone is rapid and
practically instantaneous in the presence of a trace of
copper, but oxidation of the cyanate is relatively slow.
Ozone is generated in commercially available
equipment and must be introduced in a manner to
ensure intimate contact with the entire waste solution.
This may be done in tray or packed columns or by
dispersion of the ozonized air through diffuser plates at
the bottom of the chamber.
This treatment method has found application in a few
plants and has the advantage of not adding any
constituents to the water. The cost of producing ozone
is a major factor in the economic feasibility of the
process, which has become more attractive in the last
few years because of the reduced cost for generating
ozone.
Waste Plus Waste
A new approach to removing cyanides and metals
from metal finishing wastes has recently been developed
in bench scale studies conducted at the U. S. Bureau of
Mines in Rolla, Missouri. The method simply involves
slowly blending the acid wastes from the facility into the
alkaline cyanide wastes in a well-mixed closed reactor.
At a pH value near 7, the heavy metals and cyanide in
the blended waste precipitate and are easily filtered from
the solution. The applicability of the technique will
depend largely on the relative amounts of cyanide and
acid wastes produced at the plant as well as the
particular heavy metals present. Heating the metal
cyanide precipitates in the presence of air results in the
formation of relatively stable metal oxides.
Freezing
Development work on two types of freezing processes
for recovering chemicals while simultaneously purifying
metal finishing rinse waters for reuse has recently been
reported. In one case, bench scale investigations have
been conducted on a freeze drying process in which
frozen waste droplets are formed in a refrigerant
solution followed by sublimation of the water from the
crystals in a vacuum chamber. In the other, pilot plant
investigations have been carried out on a process in
which cooled metal finishing wastes are frozen in direct
contact with an immiscible fluorocarbon refrigerant. The
ice crystals, which are virtually pure water, are cleaned
to remove chemicals adhering to their surface in a
unique countercurrent washer. The concentration can be
carried to the point of saturation where the salts
precipitate out of solution.
BIBLIOGRAPHY
1. A State-of-the-Art Review of Metal Finishing Waste
Treatment, Federal Water Quality
Administration — U. S. Dept. of the Interior,
Water Pollution Control Research Series,
1201OE1E, November 1968.
2. American Electroplaters' Society, A Report on the
Control of Cyanides in Plating Shop Effluents,
Plating, Vol. 56, pp. 1107-1112,1969.
3. An Investigation of Techniques for Removal of
Chromium From Electroplating Wastes, U. S.
Environmental Protection Agency, Water
Pollution Control Research Series, 12010E1E,
March 1971.
4. An Investigation of Techniques for Removal of
Cyanide From Electroplating Wastes, U. S.
Environmental Protection Agency, Water
Pollution Control Research Series, 12010E1E,
November 1971.
5. Campbell, R. J. and D. K. Emmerman, Freezing and
Recycling of Plating Rinsewater, Industrial Water
Engineering, pp. 38-39, June/July 1972.
6. Culotta, J. M., Treatment of Cyanide and Chromic
Acid Plating Wastes, Plating, Vol. 52, No. 6, pp.
545-548,1965.
7. Day, R. V., Disposal of Plating Room Wastes,
Plating, Vol. 46, pp. 929-931, 1959.
S.Easton, J. K., Electrolytic Decomposition of
Concentrated Cyanide Plating Wastes, Plating,
Vol. 53,1340-1342, 1966.
9. Kunin, R., Ion Exchange for the Metal Products
Finisher, Products Finishing, April 1969.
10. Kushner, J. B., Rinsing, Pollution and Natural
Recycling of Plating Baths, Metal Finishing, pp.
36-39, July 1971, pp. 54-58, August 1971.
11. Lancy, L. E., An Economic Study of Metal Finishing
Waste Treatment, Plating, Vol. 54, pp. 157-161,
February 1967.
12. Lancy, L. E., Pollution Control in Plating
Operations, Chapter 12, Industrial Pollution
Control Handbook, Edited by Herbert F. Lund,
McGraw-Hill Book Co., 1971.
13. Scrota, L., Treatment of Chromate Wastes, Metal
Finishing, Vol. 55, pp. 65-67, September 1957.
14. Spatz, D. D., Electroplating Waste Water Processing
With Reverse Osmosis, Products Finishing, pp.
79-89, August 1972.
IS.Sondak, N. E. and B. F. Dodge, The Oxidation of
Cyanide-Bearing Plating Wastes by Ozone,
Rating, Part I, pp. 173-180, February 1961,
Part II, pp. 280-284, March 1961.
16. Yuronis, D., Metal Finishing Waste Treatment:
Comparative Economics, Plating, Vol. 55, pp.
1171-1174,1968.
17. Zievers, J. F., R. W. Grain, and F. G. Barclay, Waste
Treatment in Metal Finishing: U. S. and
European Practices, Plating, Vol. 55, pp.
1171-1179, November 1968.
-------
CONTROL AND PREVENTION OF MINE DRAINAGE
R. D. HILL
U. S. Environmental Protection Agency
Cincinnati, Ohio
SOURCE
Associated with most ore and coal bodies are sulfides
and/or sulfosalts. The most common sulfides are the
iron, i.e., pyrite (FeS2), pyrrhotite, and marcasite. In
addition, there are numerous other sulfides and
sulfosalts. The general formula for sulfides is AmXn
where A consists of the metallic elements or sometimes
arsenic, antimony and bismuth (1). The general formula
for sulfosalts is AmBnXp. The elements found in sulfides
and sulfosalts are shown in Table 1. The diversity of the
combinations of the chemical elements is tremendous,
over 125 occur naturally. Thus, a potential of trace
metals in discharges from mines is always present.
Iron sulfides when exposed to air and water oxidize to
form ferrous iron, sulfate, and hydrogen (equation 1).
Pyrite also can be oxidized by ferric iron (equation 2).
The reaction may then proceed to form ferric hydroxide
and more acid (equations 3 and 4).
materials associated with the area (clays and minerals),
and the chemical characteristics of the metal ion and
water. The solubility of the metal is a primary factor.
TABLE 1 ELEMENTS IN SULFIDES AND
SULFOSALTS*
Sulfides (AmXn)
A
Ag
Cu
Zn
Fe
Co
Cd
Pb
Hg
As
Ni
S
Se
X
As
Te
Rarely Found
Ru
Mn
Ca
Sb
Bi
Pt
Sn
Mo
W
Ti Sb
Au
Bi
2FeS2 + 2H2O + 702 -> 2FeSO4 + 2H2SO4
(1)
Sulfosalts (AmBnXp)
FeS2
8H2O
15Fe2+ +
2S42 + 16H+ (2) — — —
4FeS04 + 202 2H2SO4 -> 2Fe2(SO4)3 + 2H2O (3)
Fe(SO4)3 + 6H2O -> 2Fe(OH)3 + 3H2SO4 (4)
As seen by the equations, for each mole of iron sulfide
oxidized, four moles of acid are produced. The result is
the lowering of the pH of the water draining from the
material. At the lower pH levels, the heavy metals are
more soluble and enter into the solution. As the iron
sulfides oxidize, the associated sulfides and sulfosalts
are either oxidized or exposed to conditions conducive
to their breakdown with the release of diverse metallic
and nonmetallic ions to the environment.
Under certain proper conditions, any of the ions
shown in Table 1, may be present in the drainage. For
example, the breakdown of chalcopyrite (CuFeS2)
would release copper and iron. However, gold, silver, and
selenium are often associated with chalcopyrite and also
may be present. The metal ion's in the drainage will
depend on the sulfide and sulfosalts present, the
A
Cu
Ag
Pb
Sn
B
As
Sb
Bi
Sn
X
S
* Reference 1.
Mine drainage occurs not only from the mine itself,
but also from waste dumps and tailings areas. The latter
two sources often have a higher concentration of metal
ions because the sulfides have been concentrated in these
locations. In Table 2, examples of mine drainage are
presented.
PREVENTION
The ultimate solution to the mine drainage problem is
preventing its formation. As noted in equations 1
through 4, the reaction is dependent on air (oxygen) and
water coming in contact with the sulfides. In addition to
91
-------
92
CYCLING AND CONTROL OF METALS
TABLE 2 EXAMPLES OF MINE DRAINAGE
Source
pH
SCU.mg/l
Acidity, mg/1
Fe2,mg/l
Fe3 , mg/1
U,mg/l
Zn, mg/1
Ni, mg/1
Co, mg/1
Cu, mg/1
Mn, mg/1
Al, mg/1
Hg, mg/1
Pb.mg/1
Cd, mg/1
Li, mg/1
V,mg/l
Ag,mg/l
Ti, mg/1
Mg, mg/1
Ca,mg/l
K,mg/l
Na, mg/1
As, mg/1
P,mg/l
Tailings pond
Ontario*
2.0
7,440
14,600
1,450
1,750
72
11.4
32
3.8
3.6
5.6
588
-
0.67
0.05
0.07
20
0.05
15
106
416
69.5
920
0.74
5
Mine adit Mine adit
Colorado Idaho
2.6 3.2
1,610
- -
5
213
- —
17 18.8
0.46
- -
3.9 0.06
8.0
77
0.03
03 2.5
0.07 0.05
— —
— —
<0.01
— —
— —
— —
— —
— —
0.07 0.07
- -
Mine adit
Montana
-
—
44
2
16
-
0.14
-
-
0.12
12
0.2
<0.005
0.02
0.001
—
—
—
—
3.7
112
_
6.7
<0.01
1.7
•Reference 1.
water being a reactant, it serves as the transport media
for the metals. All prevention techniques are based on
excluding water and/or air from the mining
environment.
Air
Air is necessary during the active operation of an
underground mine. After the ore has been extracted,
excluding air should be an integral part of the mining
plan. As areas are worked out, blockages should be made
to prevent air from entering that section of the mine.
Mines should be developed downdip so that they flood
when abandoned. In this manner, water serves as an
oxygen barrier. Injecting solid material into the mine,
such as slope filling, should be encouraged and
expended. Not only can the mine drainage problem be
decreased by blocking the flow of air, but a solid waste
disposal problem can be resolved simultaneously.
Sealing adits to prevent air from entering an
underground mine has been in practice in the coal fields
since the 1920's. This procedure, at its best, has been
only marginal. Seals can be built to prevent air froin
entering the adit, but air reaches tie mine readily
through the fractured outcropping and overburden. With
each change in barometric pressure, air is pumped in and
out of the mine. Air sealing may be an acceptable
method in some hard rock mines that have tight
outcrops and overburdens.
Bulkhead or hydraulic mine seals have been shown to
be successful (2). For this method a seal is built in the
adit and the outcrop is grouted to prevent water from
leaving the mine. In time, the mine workings are flooded
and oxygen is excluded from the sulfides.
Excluding oxygen from the active surface nine is
impossible. Usually there is a delay between the time the
sulfides are exposed to air and acid mine drainage is
formed. High sulfide bearing material should be exposed
for the shortest time possible. As part of the mining
operation, this material should be covered with material
containing little or no sulfides. The cover material acts as
an oxygen barrier. Wind and diffusion are the only
-------
MINE DRAINAGE
93
driving forces for moving air through the cover material
to the sulfides. The cover material should be vegetated
with grasses, legumes, shrubs, forbs, etc. Not only does
the vegetation serve to stabilize the cover material and
prevent it from eroding, but upon dying, it decays and
acts as an oxygen absorber.
Waste dumps at mines are major sources of mine
drainage and should be constructed to prevent air
movement into them. Sound techniques are compacting
waste material as it is placed and sandwiching layers of
compacted clay between layers of waste. The slopes of
the dumps should be kept to 33 percent or less to
prevent wind from driving air into the pile. Upon
abandonment, the surface of the pile should be sealed
with an air barrier. Although many different materials
have been evaluated, soil still remains the best. As in the
case of surface mines, the surface should be vegetated.
Water
Enough water is usually available in the moist air
within an underground mine or within the material itself
in a surface mine or waste dump that the requirement
for the formation of mine drainage is met. The other
function of water is as a transport media. It flushes the
oxidation products from the sulfide and carries them
into the environment. By controlling the water, these
products can be contained.
Provisions should be made to prevent water from
entering the mining environment, except where it is to
be used for flooding and an oxygen barrier. Diversion
ditches, dewatering of the working, and sealing of
fractures are just a few of the methods available. Water
that does enter the workings should be removed as
rapidly as possible.
CONTROL
Several methods are available to treat the mine
drainage that cannot be prevented.
Neutralization
The most commonly used method for treating acid
mine drainage and removing heavy metals is
neutralization. A typical system would include adding an
alkaline reagent, mixing, aerating, and removing the
precipitate. Alkaline reagents that may be used are
ammonia, sodium carbonate, sodium hydroxide,
limestone, and lime. In most cases, lime is used because
of its lower cost and higher reactivity.
Most heavy metals tend to precipitate as the pH is
raised. In Table 3, typical pH ranges at which various
metals will precipitate are presented. Metals such as
copper, zinc, iron, aluminum, manganese, nickel, and
cobalt can be reduced to low levels, less than half mg/1,
with pH adjustment, precipitation, and solids separation.
Cadmium, lead, and mercury precipitation may be
incomplete and other chemical treatment will be
required (3).
In removing iron, aeration is used to convert Fe II to
TABLE 3 PRECIPITATION OF HEAVY METALS
BY pH CONTROL
Ion
Felll
A1III
Cr III
Pbll
Cull
pH Range
3.5-4.5
4.5-6.0*
5.5-6.5
6.0-7.0
6.5-7.5
Ion
Nail
Cdll
Hgll
Fell
Mnll
pH Range
7.0-8.0
7.0-8.0
7.5-8.5
7.5-9.0
8.5-9.5
*Note: Al will become soluble again at pH greater than 7.5.
Fe III to take advantage of the precipitation of Fe III at
a lower pH.
In most cases, lime is used for neutralizing. Except for
limestone, it is the cheapest reagent, and it also reacts
rapidly. Its disadvantage is that voluminous sludge is
produced. Although limestone is cheaper and produces a
denser sludge, it is not effective above a pH of 6.5
because of the slow attack of limestone by acidity at
higher pHs. Two-stage treatment with limestone
followed by lime appears to offer the advantages of both
reagents. The Japanese have studied this process on
discharges containing iron, zinc, and manganese (4), and
have a plant that employs it for zinc, cadminum, and iron
(5). EPA has studied its use on coal acid mine drainage
(6). Two or more stage treatment with the proper
selection of pH can be used to separate heavy metals
with subsequent recovery (3,7).
Although neutralization can be used to remove heavy
metals and a portion of the sulfate, the resulting water is
high in dissolved solids and sulfate. The disposal of the
sludge is also a problem.
Ion Exchange
Various ion exchange schemes have been applied to the
treatment of coal acid mine drainage (8). These schemes
can upgrade the water quality to potable use.
Modification can be incorporated to recover heavy
metals. Ion exchange has not received wide acceptance
because of difficulties encountered with resin fouling,
interfering ions, limited loading capacity, cost of
operating, and disposal of regenerating solutions. Further
development is needed.
Reverse Osmosis
Reverse osmosis (R.O.) has effectively removed
multivalent ions from mine drainage. Table 4 presents
data from the treatment of coal mine drainage. All heavy
metals should be removed at about this same level (99
percent or better). Reverse osmosis is a concentrating
process in which the pollutants are contained on one
side of a membrane while the water passes through.
Water recoveries (percent of water feed to unit that is
available as treated water) have been as high as 90
percent. Water recovery is limited by the precipitation of
material on the membrane when they have been
-------
94
CYCLING AND CONTROL OF METALS
TABLE 4 TREATMENT OF MINE
REVERSE OSMOSIS
Element
Ca
Mg
Fe, total
Al
Mn
Cu
S04
Acidity
Specific conductance
DRAINAGE BY
Removal— %
98 -99.8
98.5-99.8
98.5-99.9
91.7-99.2
97.8-99.1
98.7-99.5
99.3-99.9
81.0-91.7
95.0-99.9
concentrated beyond the materials saturation point.
Calcium sulfate is usually the first material to be
precipitated in mine drainage. Equations have been
developed to predict the highest water recovery
allowable under any influent condition (9,10).
Since R. 0. is a concentrating system, the disposal of
the waste stream is a major problem. The concentrated
heavy metals in the waste stream would lend themselves
better to processes for recovering the metals. For
systems where recovery is not practiced, EPA has
developed a system whereby the waste stream is
neutralized, the sludge removed, and the neutralized
water returned to the influent of the R. 0. unit. This
system has been named "Neutrolosis" and has obtained
water recoveries in excess of 99 percent (11).
Cementation
Taking advantage of the electromotive force between
metals can be used to remove and recover metals from
mine drainage. A notable example is the recovery of
copper by passing the copper bearing water through
shredded iron. The copper is "cemented" to the iron.
The process may have application in other situations (3).
Electrolytic
With the use of electrodeposition processes, several
metals, such as copper and iron, can be removed from
mine drainage. The metal is deposited on the cathode of
an electric cell from which it can subsequently be
recovered. This method is only applicable to waters with
very high concentrations of the metal.
Electric cells can also be used to oxidize metals from
the plus three state to the plus two state before
neutralization or other treatment. Studies have been
made on converting ferrous iron to ferric iron in the acid
state by this method (12).
SUMMARY
Many different heavy metals can be found in mine
drainage because of the variety of ores and minerals
associated with mining operations. The first approach to
control heavy metal discharges should be preventing the
formation of the mine drainage. Many ways are available
tor controlling air and water in mining operations. For
the mine drainage that cannot be prevented, several
treatment methods are available, some of which offer
ways of recovering the metals.
REFERENCES
1. Hawley, J. R., The Problem of Acid Mine Drainage
in the Providence of Ontario, Ontario Water
Resources Commission, Toronto, Canada, 1972.
2. Foreman, J. W., Evaluation of Mine Sealing in Butler
County, Pennsylvania, Fourth Symposium on
Coal Mine Drainage Research, Bituminous Coal
Research, Incorporated, Monroeville,
Pennsylvania, April 1972.
3. Dean, J. G., F. L. Bosqui, and K. H. Lanouette,
Environmental Science & Technology, 6, 6 June
1972.
4. Shimoiizaka, J., S. Hasebe, H. Sato, and T.
Takahoski, The Utilization of Calcium Carbonate
and Calcium Hydroxide as Neutralizing Agents in
Acidic Mine Water Disposal, Technology Reports
of the Iwate University, Vol. 5, March 1971.
S.Veta, E., K. Sasamoto, and K. Fukuda, Bacterial
Oxidation Treatment of Waste-Water at
Hosokura, Joint meeting MMIJ-AIME, Paper T
IIIb3, Tokyo, May 1972.
6 Wilmoth, R. C., R. B. Scott, and R. D. Hill,
Combination Limestone-Lime Treatment of Acid
Mine Drainage, Fourth Symposium on Coal Mine
Drainage Research, Bituminous Coal Research,
Incorporated, Monroeville, Pennsylvania, April
1972.
7. Ikegami, T., Recent Practice of Waste-Water
Treatment at Yanaham Mine, Joint meeting
MMIJ-AIME, Paper T IIIb2, Tokyo, May 1972.
8. Holmes, J. and K. Schmidt, Ion Exchange Treatment
of Acid Mine Drainage, Fourth Symposium on
Coal Mine Drainage, Bituminous Coal Research,
Incorporated, Monroeville, Pennsylvania, April
1972.
9. Gulf Environmental Systems Company, Acid Mine
Waste Treatment Using Reverse Osmosis, EPA
Water Pollution Control Research Series #14010
DYG, Washington, D. C., August 1971.
10. Wilmoth, R. C., D. G. Mason, and M. Gupton,
Treatment of Ferrous Iron Acid Mine Drainage
by Reverse Osmosis, Fourth Symposium on Coal
Mine Drainage, Bituminous Coal Research,
Incorporated, Monroeville, Pennsylvania, April
1972.
11. Hill, R. D., R. C. Wilmoth, and R. B. Scott,
Neutrolosis Treatment of Acid Mine Drainage,
26th Annual Purdue Industrial Waste
Conference, Lafayette, May 1971.
12. Tyco Laboratories, Incorporated, Electrochemical
Treatment of Acid Mine Waters, EPA Water
Pollution Control Research Series #14010 FNQ,
02/72 Washington, D. C., 1972.
-------
CONTROL OF PARTICULATE LEAD EMISSIONS
FROM AUTOMOBILES*
E. N. CANTWELL, E. S. JACOBS, W. G. KUNZ, JR., AND V. E. LIBERI
E. I. duPont De Nemours & Co. (Inc.)
Wilmington, Delaware
INTRODUCTION
Recent proposed regulations concerning fuels and fuel
additive content by the U.S. Environmental Protection
Agency (EPA) call for the general availability of one
grade of lead-free fuel by July 1, 1974 for use in 1975
and later model cars equipped with catalytic devices (1).
In addition, the proposals call for a scheduled
reduction of the lead content of regular and premium
grades of gasolines. Under this reduction schedule the
maximum content would be limited to 1.25 grams of
lead per gallon by January 1, 1977. EPA justified this
reduction schedule on the basis that automotive
emissions of lead should be reduced sufficiently to
reduce the lead content of the air in urban areas by 60
percent by 1977. The implication is that such reductions
are best accomplished by regulating the lead content of
gasoline. However, there is an alternative approach
which is more consistent with the position that control
regulations should be based on tail pipe emission
standards rather than regulation of fuel and fuel additive
content. Exhaust particulate lead traps used on cars
burning leaded gasoline have demonstrated the ability to
significantly reduce motor vehicle lead emissions (2, 3).
During the past seven years a number of different
studies have been conducted at duPont to develop
methods and means to measure, characterize, and
control vehicle exhaust particulate as well as gaseous
emissions. Habibi has developed and described the use of
two different vehicle exhaust particulate sampling
systems (4). One measures the total particulate lead
emission rate from cars operating under normal driving
conditions. The second system, based on a proportional
sampling principle, provides size classification, and other
characterization on a representative sample of the
particulate matter. A third approach to measure and
characterize vehicle exhaust particulate has been
described by Pierrard and Crane (5). They measured the
atmospheric visibility and soiling effects of exhaust
particles from cars using different gasolines. In addition
to using the Habibi sampling procedures, they measured
the effect on the atmosphere of exhaust particulate
emissions from cars driven in a 1-1/4-mile long unused
Pennsylvania turnpike tunnel. All three of these exhaust
particulate measurement techniques were used in
evaluating the efficiency of the trap systems described in
this paper.
A number of trap systems for control of automotive
exhaust particulate have been developed by duPont and
reported previously (2). Brief descriptions of these
systems are included in this paper along with new data
on the total lead removal efficiency of lead traps for
different size lead particles, and airborne lead emissions
from production and trap-equipped cars driven on the
road in the unused Pennsylvania turnpike tunnel. In
addition, one trapping system was combined with a
gaseous emission control system to provide control of all
gaseous and particulate emissions from a vehicle. The
development and performance of a new type of lead
trap, designed to replace the exhaust muffler of existing
cars on the road, last the life of the vehicle, and reduce
the airborne lead emissions from cars by greater than 65
percent is presented in this paper.
EXHAUST PARTICULATE EMISSIONS - TEST
METHODS
The particulate matter emitted from automobiles is a
complex mixture of leads, sals, iron as rust, alkaline
earth compounds, soot, carbonaceous material, and tars.
Some of the particulate matter found in the vehicle
exhaust is generated in the engine combustion chamber
and is nucleated and agglomerated in the car's exhaust
system before it is emitted from the tail pipe. On the
other hand, a large portion of the particulate material
generated in the engine subsequently deposits on various
surfaces of the exhaust system. Later, this deposited
material flakes off and becomes re-entrained in the
*Paper reprinted with permission of the Society of Automotive
Engineers (SAE). Presented at National SAE Meeting, May 26,
1972, Detroit, Michigan, and published as SAE paper No.
720672.
95
-------
96
CYCLING AND CONTROL OF METALS
exhaust gas to be emitted from the car. Thus, many
factors, such as previous history of car operation, age of
exhaust system, mileage, age of car, type of fuel and
mode of vehicle operation during test, can affect the
total paniculate emission rate.
The complexity of the particulate emission process
makes the task of measuring the amount of emitted lead
very difficult. Satisfactory sampling cannot be
accomplished, for instance, by simply inserting a probe
in the tail pipe of an operating vehicle and collecting the
effluent for a short time (3). Such sampling procedures
can result in the collection of samples with abnormal
particle size distributions as well as unrealistic total
particulate emission rates. Factors contributing to these
discrepancies include nonuniformity of the particulate
profile in the tail pipe, nonproportionalityof the sample,
and inaccurate sampling of large particles. Furthermore,
with a short test interval and without conditioning of
the vehicle before the test, the emission rate may be
abnormal also.
Satisfactory methods to provide meaningful data on
particulate emission rates must (a) employ a suitable
sampling system for isolating and collecting particulate
matter, (b) utilize vehicle driving patterns which
simulate average vehicle operation and are important in
affecting particulate emission processes, (c) provide for
tests of adequate duration to insure good repeatability,
and (d) employ a vehicle conditioning period prior to a
particulate emission test. Three different techniques
were used to monitor the particulate lead emission rates
of the production and emission control-equipped
vehicles discussed in this paper.
Total Lead Emissions
All "total" lead emission rates reported in this paper
were measured with a total exhaust filter (4) attached to
the vehicle tail pipe while the car was operated on a
programmed chassis dynamometer (PCD) according to
the Federal mileage accumulation (Modified AMA)
schedule (6).
The total exhaust filter shown in Figure 1, which
mounts directly on the tail pipe of the car is a cylindrical
drum, 18 inches in diameter, 24 inches long, and packed
with a high efficiency fiberglass medium. The total
vehicle exhaust flows through the filter which is
designed to give a low pressure drop across the filter -
less than two inches of water at 70 miles per hour cruise.
The pressure drop across the filter increases with
accumulation of material on the filter. In practice the
filters are removed when pressure drop exceeds six
inches of water so that the use of the filter does not
at feet the vehicle operation. This increased pressure drop
corresponds to about 500 miles of continuous hot-cycle
operation for a production vehicle and as much as 2,000
to 4,000 miles with a trap-equipped car. However, the
filter is usually changed every 1.000 miles for the latter
vehicle to provide more accurate data and as a
FILTER HOLDER TOP PAN
SUPPORT RODS
HOLDING TOP AND
BOTTOM PANS
FILTER PAN HOLDER
VEHICLE EXHAUST
Figure 1. Total exhaust filter.
convenience in the operation.
After each test, the filter unit is disassembled and lead
on the filter medium is extracted in hydrochloric acid.
The lead deposited on the inlet pipe and internal parts of
the holder is extracted with an aqueous solution of the
tetrasodium salt of ethylenediamine tetraacetic acid.
These solutions are analyzed for lead by atomic
absorption. The efficiency of this filter for exhaust lead
removed has been tested in a number of experiments
reported previously (4). Under normal driving
conditions, the unit is 99 percent efficient for lead
removal.
Lead Particle Size
The exhaust particulate sampling system developed by
Flabibi (4) and shown in Figure 2, was used in this study
to determine the amount of lead emitted as a function
of lead particle size. In this system, the total exhaust gas
from a vehicle operating on the PCD is introduced into a
duct 22 inches in diameter and 40 feet long. The exhaust
is diluted with filtered ambient air using the constant
volume proportional sampling principle. The average
dilution of the exhaust during the test cycle was 35 to 1,
which is sufficient to prevent condensation and to cool
the exhaust to near ambient temperatures. A time of
approximately five seconds is required for the
exhaust-air mixture to travel the length of the tunnel
and reach the sampling station.
To measure lead particle size, an isokinetic sample of
the uniformly mixed aerosol is taken at the sample
station using an Andersen sampler (4) and a Monsanto
Impactor (4). These two impactor units are used
DYNAMOMETER
UNIT
AIR
FIBERGLASS
FILTER
BLOWER
SAMPLING
PROBES
Figure 2. Proportional sampling system for exhaust
particulate matter.
-------
AUTOMOBILE LEAD EMISSIONS
97
simultaneously to provide a wide size distribution
measurement of exhaust lead particles over the range of
0.3 to 9.0 microns equivalent diameter. Particles smaller
than 0.3 micron equivalent diameter are collected on an
absolute filter downstream of each impactor unit. As
discussed by Habibi (4), there is some gravitational
settling of the large particles present in the exhaust along
the tunnel as well as some turbulent deposition of
particles on the tunnel walls. The amount of this
particulate lead deposited in the tunnel is determined
after each run and is included in the greater than nine
micron equivalent diameter size fraction. Each size data
point reported in this study represents the average of at
least three separate tests. Each test was of about 200
miles duration and was conducted on the PCD according
to the Federal mileage accumulation schedule.
Airborne Lead Emissions
"Airborne" lead was determined by measuring the
amount of lead remaining in the air in a sealed turnpike
tunnel after driving vehicles back and forth on the tunnel
roadway (5). Limited measurements have been made to
determine the size distribution and average particle size
of the "airborne" lead remaining in the tunnel after
driving production vehicles through the tunnel. These
data show that the average lead particle size is
approximately 0.25 micron mass median equivalent
diameter which as discussed later is the average size of
the lead particles found in urban atmospheres.
For each test, the car was started cold after a 16-hour
soak period and manually driven back and forth over a
fixed course (Figure 3) for a total of twenty-four
7-mode Federal test cycles (6) with the aid of an
audiotape prompter. An absolute filter sampler mounted
on the roof of the test car collected a spatially integrated
sample of airborne tunnel particulate matter over the
driving course during each driving period. Prior to
conducting the test, the car was conditioned by driving a
total of fifty 7-mode Federal test cycles on the road.
The turnpike tunnel was conditioned prior to each test
as previously reported by Pierrard and Crane (5). This
conditioning consisted of flushing the tunnel with clean
ambient air for about one hour prior to each test or for
such time as required to lower the tunnel carbon
monoxide concentration and light scattering coefficient
-TUNNEL LENGTH 6200 FT
DRIVING COURSE
r* 4445 FT ~
'OPTICAL PATH
'r* 2615 FT—*"
COLD START;-*-
'-«—»•• FILTER
735 FT SAMPLER
to the same level as the outside air.
Since the test conditions were the same for all cars,
the actual reduction of airborne lead achieved by use of
trap-equipped cars rather than production vehicles can
be determined directly by comparing the amount of lead
collected by the roof-top filter during the operation of a
trap-equipped vehicle to the amount collected during the
operation of a production vehicle. Such results, after
correcting for a blank and normalizing for the volume of
air sampled, are discussed later.
In addition, the airborne lead emission rates from cars,
expressed in grams of lead per mile, have been calculated
from the lead collected on the filter. These data provide
a means for direct comparison of the emission rate of
airborne lead from cars operated on the road to the
emission rates of lead from cars operated on the PCD.
Such data, shown in Tables 1, 6, 7, and 9, were
calculated from a knowledge of effective tunnel volume,
volume of air filtered, sampling time, mean car speed,
initial air lead concentration, and mass of lead on the
filter.
LEAD EMISSIONS FROM PRODUCTION VEHICLES
The lead emission rates of several production vehicles
have been measured and the data are summarized in
Table 1. The emissions are expressed in terms of total
emission rate of lead as measured by the total exhaust
filter while the cars were driven on the PCD and airborne
emission rate as measured in the Pennsylvania turnpike
tunnel. The average total lead emission rate is
approximately 0.11 gram of lead per mile. The airborne
lead emission rate was 0.050 gram of lead per mile or
less than half the total amount emitted. As will be
shown later (Figures 7 and 8) the lead emission rate of a
production vehicle is quite variable even over relatively
long sampling periods of up to several hundred miles.
The values shown for the emission rates in Table 1 are
TABLE 1 LEAD EMISSION RATE FROM
PRODUCTION VEHICLES
Vehicle
Mileage
Emission rate,
grams of lead
per mile
Total
Airborne
Figure 3. Pennsylvania Turnpike tunnel.
F47
C-76
C-82
H-l
CW-1
CW-21
C-40
C-83
0 to 54,000
0 to 5 5, 000
8,000
41 ,000
21,000
1 1 ,000
0 to 28 ,000
21,000
Average
0.086
0.106
0.102
0.14
0.108
0.039
0.061
0.047
0.055
0.050
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98
CYCLING AND CONTROL OF METALS
the average results of at least three runs at the indicated
mileages. In view of the variability in emission rates at
different mileages on a given car and the variability
among cars it is not possible to measure the amount of
lead emitted from a production vehicle at any one time
and expect to obtain a representative value of the lead
emission rate of vehicles. Conversely, as is shown also in
Figures 7 and 8, the lead emission rate of a vehicle
equipped with a trapping system is relatively constant
and the variations are much less than that for the
standard vehicle. As a consequence, in all subsequent
comparisons of the lead emission rates for the trap cars
with that of standard cars the measured value of a given
trap car will be compared with the average values for
production vehicles as given in Table 1.
The size distributions of the lead emitted from three
of the production vehicles listed in Table 1 have been
determined at several points during mileage
accumulation on these vehicles using the Federal mileage
accumulation schedule (6). These data are summarized
in Table 2. The total amount of lead emitted from the
vehicles during the size measurements averaged just less
than 0.1 gram per mile which is a quite close check on
the total value given in Table 1. The emitted lead
associated with particles greater than nine microns in
equivalent diameter averaged 0.031 gram per mile or
approximately 30 percent of the total amount of lead
emitted. This material is relatively coarse and would not
be expected to remain airborne for any significant length
of time. Approximately 0.02 gram of lead per mile was
emitted in the size range from nine to one microns
equivalent diameters; particles of this size range might
lemain in the atmosphere for at least a short length of
time. The rate of lead emission of particles of less than
one micron in diameter was equal to 0.031 gram per
mile or about 30 percent of the total lead emitted. These
small particles would become airborne and remain
suspended for a significant length of time. A further
breakdown of the submicron lead particles shows that
approximately 0.022 gram of lead per mile or about 20
percent is emitted as particles below 0.3 micron
equivalent diameter.
In the same manner that the total lead emission rate
varies with mileage, the amount of lead emitted in
various size fractions also varies. However, the variation
in emission rate is more pronounced for the large
particles, i.e., those greater than nine microns. This
variability is to be expected since the large particles are
the result of re-entrainment of material which flakes off
the walls of the exhaust system. The amount of material
available for re-entrainment and the extent of flaking is
dependent upon previous driving history of the car as
well as the mode of car operation or the driving cycle
used during the emission test. Thus, with relatively new
cars, there will be little or no material available for
re-entrainment in the exhaust system giving rise to very
low emission rate of large particles. Similarly, under
steady-state driving conditions there is little thermal
expansion and contraction of the exhaust system and
flaking and subsequent re-entrainment is minimal
The smaller lead particles are combustion generated
and thus the absolute lead emission rate is relatively
constant as long as the test cycle or driving condition
remains the same. However, due to the wide fluctuations
of the emission rate of large particles, the relative
amount of the small particles compared with the total
amount emitted will fluctuate also. For example,
measurements made with relatively low mileage vehicles
or measurements made under steady-state test
conditions, where the emission rate of large particles
TABLE 2 LEAD PARTICLE SIZE DISTRIBUTION FROM PRODUCTION
VEHICLES
Vehicle
Mileage
Emission rates,
grams of lead per mile
Size in microns
C-40
c-;o
C-40
C-40
F-47
F47
F-47
C-76
C-76
C-76
5 ,000
16,000
21,000
28,000
3,000
20,000
55,000
3,000
20,000
55,000
Average
Total
0.102
0.095
0.083
0.115
0.086
0.106
0.098
>9
0.028
0.037
0.036
0.066
0.008
0.027
0.024
0.015
0.056
0.017
0.031
9 to 1
0.029
0.024
0.017
0.028
0.008
0.010
0.008
0.023
0.022
0.008
0.018
<1
0.046
0.034
0.030
0.022
0.022
0.020
0.017
0.044
0.044
0.027
0.031
<0.3
0.031
0.024
0.022
0.013
0.019
0.015
0.015
0.031
0.028
0.022
0.022
-------
AUTOMOBILE LEAD EMISSIONS
99
would be very low, will lead to the erroneous conclusion
that most of the lead is omitted from the car as very fine
particles. These observations undoubtedly explain why
some investigators have reported that the majority of the
lead is emitted as submicron particles.
ATMOSPHERIC LEAD PARTICLE SIZE
To place the size of the lead emitted from production
vehicles in proper perspective, it is worthwhile to
examine the particle size distribution of the lead in the
atmosphere in various urban areas. Many investigators
have made such measurements and their data are
summarized in Table 3 (7, 8, 9). The most
comprehensive work was carried out by Robinson and
Ludwig who sampled the atmosphere in 59 urban areas
and found that the average size or mass median
equivalent diameter of the particles which contain lead
was 0.25 micron in diameter. This means that one-half
of all the lead by weight was associated with particles of
greater than 0.25 micron in diameter and one-half of the
lead by weight in the air was associated with particles of
less than 0.25 micron in diameter. Other investigators
have also measured average size of lead-containing
particles in the atmosphere and in general their values
are reasonably in agreement with those of Robinson and
Ludwig. Habibi and Pierrard of duPont also measured
the size distribution of atmospheric lead at two widely
separated locations and as shown in Table 3 found the
average particle size to be approximately 0.25 micron.
Thus, an average particle size for the lead-containing
particulate matter in the atmosphere would appear to be
0.25 micron mass median equivalent diameter.
When the lead particle size distribution emitted from
production vehicles, as given in Table 2, is examined in
terms of the size of the lead particles in the atmosphere,
it can be seen that about 20 percent of the lead emitted
from production vehicles consists of particles smaller
than the average size of the lead particles found in the
urban atmosphere. Thus, for a trapping system to be
effective in reducing the amount of lead in the urban
atmosphere it must reduce the total amount of lead
emitted from a vehicle. But, it must also be effective in
reducing the airborne lead which includes the lead
emitted as particles smaller than one micron and, in
particular, the particles smaller than 0.25 micron
equivalent diameter.
LEAD EMISSIONS
VEHICLES
FROM TRAP-EQUIPPED
A number of different studies have been conducted at
duPont to determine the best way to reduce the lead
particulate exhaust emissions from cars operated on
commercial gasolines. These studies have included
electrostatic precipitation, changes in the chemical
composition of the particulate lead, as well as chemical
and mechanical filtration. However, the most durable
and effective way to attain this reduction is to separate
the particles from the gas stream and then retain or trap
the particulate matter in the exhaust system using
inertial separation devices.
Several such exhaust particulate trapping systems have
been devised and described previously (2). One of these
systems designated Trap System A, consists of the
substitution of fluted pipes in place of the standard
exhaust pipes and the use of a cyclone trap. The fluted
pipes increased the heat transfer from the exhaust gas to
the ambient air and provided the additional cooling
necessary to initiate particulate lead formation in the
TABLE 3 SIZE OF ATMOSPHERIC LEAD
PARTICLES
Investigator
Robinson and
Ludwig
Lee,
Robinson and
Wagman
Lundgren
Habibi
Pierrard
Weighted
Location
sampled
59 urban
areas
Downtown
Cincinnati
Suburban
Cincinnati
Riverside,
California
Wilmington,
Delaware
El Monte,
California
Average
Average size
(mass median
equivalent diameter),
microns
0.25
0.2
0.4
0.5
0.24
0.2
0.25
-------
100
CYCLING AND CONTROL OF METALS
exhaust system. The particles of lead which were
formed in the fluted exhaust pipe were removed from
the exhaust stream in simple cyclone traps and the lead
particles stored in the cyclone trap collection chamber.
This trap system was operated for 64,000 miles on the
PCD using the Federal mileage accumulation schedule
and a commercial gasoline containing 2.5 grams of lead
per gallon. When the lead emission rates from this
vehicle, as determined by the total exhaust filter, were
compared with those of a production car it was found
that the trapping system reduced the total lead emissions
by 70 percent.
Trap System B
A more advanced particulate trap system designated
Trap System B was devised to provide additional cooling
and agglomeration. A schematic diagram of this trap
system is shown in Figure 4. A dual exhaust system was
used. On each side of the dual system two pipes were
lined internally with wire mesh to promote
agglomeration of the particles. In addition, the dual
pipes exhausted into a common box filled with fine wire
mesh. The gases flowed from this mesh box to two
cyclone particle separators, one in each of the rear
fender wells. The design of the cyclone separation box is
shown in Figure 5. A photograph of the under side of
the car with the Trap System B installed is shown in
Figure 6.
The performance of the Trap System B was evaluated
in a four-car test in which two 1969 Fords and two 1969
Chevrolets were used. One car of each make was
FLUTED PIPES
MESH
CYCLONE TRAP
LINED PIPES
MESH-FILLED BOX
Figure 4. Trap System B
CYCLONE
COLLECTION
CHAMBER
OUT
MESH WITH OPEN
FLOW TUBES
Figure 5. Cyclone separator for exhaust particulate
matter.
PKH 277
CYCL RAPS
Figure 6. Exhaust particulate matter Trap System B.
equipped with the trap system and their performance in
terms of lead emission rates compared with the
production cars which retained the unmodified
conventional exhaust systems. Mileage was accumulated
on the PCD using the Federal mileage accumulation
schedule. Commercial gasoline containing 2.5 grams of
lead per gallon was used for all mileage accumulation
and emission test work.
The total amount of lead emitted from all four
vehicles was monitored continuously throughout the
test, which lasted almost 60,000 miles, by the use of
total exhaust filters. The results in terms of grams of
lead emitted per mile of operation as a function of test
miles are shown in Figures 7 and 8 for the production
vehicles and for the vehicles equipped with Trap System
B. As previously discussed, it is obvious that the lead
emission rates from the production vehicles are quite
variable with time and that the lead emission rate
measured at any instant of time in the life history of an
automobile may not be representative of the average
amount of lead emitted over its lifetime. Conversely, the
trap system was quite effective in reducing the amount
of lead emitted and also in reducing the variations in the
amount of lead emitted. The average amounts of lead
emitted from the production vehicles and the vehicles
equipped with Trap System B throughout the 60.000
-------
AUTOMOBILE LEAD EMISSIONS
101
0.3
0.2
2
O
1969 FORDS
PRODUCTION VEHICLE
10 20 30 40
THOUSANDS OF MILES
50
60
Figure 7. Lead emission rates for 1969 Fords with and
without Trap System B.
0.3
LU
_J
i
\
-0
Q.
O 0.2
o
1969 CHEVROLETS
PRODUCTION
VEHICLE
10
20 30 40
THOUSANDS OF MILES
50
60
Figure 8. Lead emission rates for 1969 Chevrolets with
and without Trap System B.
test miles are shown in Figure 9.
In addition to measuring the total lead emission rates,
the particle size distribution of the emitted lead was
determined in the 40-foot tunnel. The data for the two
cars equipped with Trap System B are shown in Table 4.
-O
a.
O
0.12
0.10
0.08
0.06
0.04
0.02
0
PRODUCTION
PRODUCTION
1969 FORDS
1969 CHEVROLETS
Figure 9. Average lead emission rates with and without
Trap System B.
These data along with similar data obtained with the
production vehicles are shown in Figure 10. The
reduction in lead emission rate achieved with Trap
System B when compared with the lead emission rates
from production vehicles is summarized in Table 5.
Trap System B was most effective in reducing lead
emission rates of both the large and the small particles.
Trap System B reduced the total amount of lead emitted
from production vehicles by some 82 percent.
Examination of the size distribution of the emitted lead
reveals that, as expected, the trapping system was
particularly effective in reducing the large particles. The
lead particles with sizes greater than nine microns were
reduced by 94 percent. Even in the case of the smaller
size fractions, significant reductions in emission rates
were accomplished. There was an 88 percent reduction
of the amount of particles emitted in the size fraction
from nine to one microns and a 65 to 71 percent
reduction in mass of particles of less than one micron
diameter. This reduction in emission of the small
TABLE 4 LEAD PARTICLE SIZE DISTRIBUTION FROM PRODUCTION
VEHICLES WITH TRAP SYSTEM B
Emission rates,
grams of lead per mile
Vehicle
Mileage
Size in Microns
F48
F-48
F48
C-77
C-77
C-77
3,000
20,000
55,000
3,000
20,000
55,000
Average
Total
0.012
0.022
0.017
>9
0.0004
0.003
-
0.0005
0.004
0.001
0.002
9 to 1
0.0005
0.003
-
0.0006
0.005
0.002
0.002
<1
0.005
0.012
-
0.007
0.020
0.011
0.011
<0.3
0.004
0.005
—
0.005
0.010
0.008
0.006
-------
102
CYCLING AND CONTROL OF METALS
TABLE 5 LEAD EMISSION REDUCTION WITH TRAP SYSTEM B
Reduction from
production vehicle, %*
Vehicle
F-48
F-48
F-48
C-77
C-77
C-77
Mileage
3,000
20,000
55.000
3.000
20,000
55.000
Average
Total
86
79
82
>9
97
91
-
97
87
97
94
Size in microns
9 to 1
97
83
-
97
72
89
88
<1
84
61
-
78
36
65
65
<0.3
82
77
—
77
55
64
71
'See Tables 1,2, and 4 for lead emission rates.
particles is most important since these are the particles
which will tend to remain airborne and which
correspond in size to the particles containing lead found
in the atmosphere of urban areas.
The foregoing results obtained with Trap System B
demonstrate that it is feasible to control the emission of
particulate lead matter from vehicles. Furthermore, not
only is the total amount of lead emitted from the vehicle
reduced substantially, but the fine particles which could
be expected to remain airborne for significant lengths of
time are reduced also. However, this trapping system is
somewhat complex. Accordingly, simpler systems have
been devised in an attempt to reduce the cost and the
complexity of the system while retaining or improving
the high efficiency demonstrated with Trap System B.
Trap System C
A simpler version of Trap System B was devised and
S
_E
CL
O
0.03
0.02
0 01
I PRODUCTION
TRAP
SYSTEM B
> 9 9TO 1 <1 < o.3
LEAD PARTICLE SIZE, MICRONS
Figure 10. Lead emission rates from Trap System B as a
function of particle size.
has been designated Trap System C. This system, shown
schematically in Figure 11, consists of dual, fluted pipes
which serve to cool the exhaust gases and initiate
formation of the lead particulate matter. The gas flows
from the fluted pipes into a common box filled with
stainless steel wire mesh and through dual cyclone
collection traps similar to the units used in Trap System
B.
The effectiveness of Trap System C was determined by
measuring the airborne lead emission rate of production
vehicles before and after the installation of the trap
system. Two vehicles, C-82 and H-l, were tested in the
Pennsylvania turnpike tunnel as production vehicles. At
the conclusion of these tests the production exhaust
system was removed and Trap System C was installed.
The trapping systems which were installed had already
accumulated about 17,000 miles of consumer operation
in a field service test using commercial leaded gasolines
(10). After the traps were installed on the two vehicles
the cars were operated in excess of 2,000 miles on the
PCD to recondition the systems prior to the tests at the
Pennsylvania turnpike tunnel. In the case of C-94, the
car had been operated as a duPont total emission control
system vehicle for 10,500 miles (see Ref. 10 and the
CYCLONE TRAP
FLUTED EXHAUST PIPE
MESH-FILLED BOX
Figure 1 1 . Exhaust particulate matter Trap System C.
-------
AUTOMOBILE LEAD EMISSIONS
103
d 0.08 -
£
\
£ 0.06
< 0.04
Z
o
0.02
AVERAGE 0.050
H-l
CW-21
AVERAGE 0.018
C-94
EXHAUST GAS R EC IRCU LATION SYSTEM
PRODUCTION
TRAP SYSTEM C
Figure 12. Airborne lead emission rates with Trap
System C.
next section for description of these vehicles). To test
the trap system only, the gaseous emission control
system consisting of thermal reactors and exhaust gas
recirculation systems was removed, the car restored to a
production vehicle except for the Trap System C, the
vehicle operated for another 2,000 miles, and then
tested in the Pennsylvania turnpike tunnel to determine
airborne lead emission rates.
The data obtained with the vehicles equipped with
Trap System C are shown in Table 6 and are compared
with the airborne emission rates of production vehicles
in Figure 12. Trap System C was effective in reducing
airborne emission rates to an average value of 0.018
gram of lead per mile. When this value is compared with
the airborne lead emission rate of production vehicles it
can be seen that Trap System C reduced the amount of
airborne lead emitted by 64 percent.
duPont Total Emission Control System Vehicles
Trap System C has been combined with other systems
to control the gaseous exhaust emissions from vehicles
to produce a total emission control system or TECS I
vehicle (10). The components of the TECS vehicle are
AIR
PUMP
THERMAL
REACTORS
TRAPPING
SYSTEM
Figure 13. duPont total emission control system.
shown schematically in Figure 13. The exhaust manifold
thermal reactors are used in conjunction with an air
pump to provide a high temperature zone where the
hydrocarbons and carbon monoxide in the exhaust are
oxidized. An exhaust gas recirculation system is
combined with various carburetor modifications to
control the emission of oxides of nitrogen. A more
complete description of these vehicles and their
performance in controlling gaseous emissions can be
found in References (2, 10, and 11). Trap System C as
utilized in these TECS vehicles is shown in the
photograph in Figure 14.
The lead emission rates from several of the duPont
TECS vehicles have been measured and the data
summarized in Table 7. The average total lead emission
rate for these vehicles was 0.016 gram per mile. When
this value is compared with the value of the 0.108 gram
per mile for production vehicles it can be seen that the
TECS vehicles reduced the total amount of lead emitted
to the environment by 85 percent. The amount of
airborne lead emitted by the TECS vehicles as measured
in the Pennsylvania turnpike tunnel averaged 0.015 gram
per mile corresponding to a reduction of 70 percent as
compared with the airborne emission rates of production
vehicles.
TABLE 6 LEAD EMISSION RATE FROM PRODUCTION
Vehicle
C-82
H-l
C-94
VEHICLES
Mileage
20,000
20,000
13,000
Average
WITH TRAP SYSTEM C
Airborne lead
emission rate,
grams of lead
per mile
0.022
0.014
0.019
0.018
Reduction
in airborne
lead emission
rate compared
to production
vehicles, %*
56
72
62
64
*See Table 1 for airborne lead emission rate for production vehicles.
-------
104
CYCLING AND CONTROL OF METALS
MESH-FILLED BOX
FLUTED EXHAUST PIPE
CYCLONE TRAPS
EXHAUST RECIRCULATION LINE
Figure 14. Trap System C as a part of the duPont TECS.
Muffler Lead Traps
The trapping systems as typified by Systems B and C
are quite effective in reducing the emission of paniculate
lead from vehicles but they are complex and would
probably be suitable only for installation on new
vehicles at time of manufacture. In an effort to reduce
the complexity and therefore the cost of the system and
also to develop systems which might be used as
replacement items for mufflers on existing cars on the
road, a program to develop a lead trap the size and shape
of a production muffler was initiated. The basis of the
muffler lead trap is the use of a more efficient
agglomerating medium than the stainless steel wire mesh.
One method of improving the agglomeration of lead
particles is to utilize a material with high surface area
TABLE? LEAD EMISSION RATE FROM DUPONT
TECS VEHICLES
Vehicle
Mileage
Emission rate.
&rams of lead Per
C-84
C-85
C-86
C-*6
C-94
Reduction
1. 000
9.400
2b.OOO
30.000
10.500
Average
in lead
Total
0.021
0.011
0.015
0.016
85
Airborne
0.009
0.022
0.015
70
which has an affinity for the lead compounds in the
exhaust. Such a material is high surface area alumina
that has been used for a support in catalytic reactors.
Accordingly, traps incorporating high surface area
alumina in combination with cyclone separators have
been built and tested.
A muffler lead trap, designated Type 11, incorporated
extended surface alumina in the form of one-quarter
inch diameter pellets and two cyclone separators in
parallel. The design of this trap is shown in Figure 15.
This trap is the same overall size and shape as a
production muffler. Exhaust gas enters one end of the
trap, flows through the bed of alumina pellets, and into
the two cyclones. After exiting from the cyclones the
exhaust flows into a plenum chamber at the downstream
end of the trap. This trap was installed in place of the
standard muffler on a production vehicle and was
operated on the PCD under the Federal mileage
accumulation schedule for 25,000 miles. During this
time the lead emission rate was monitored and the values
obtained are shown in Table 8.
The average total lead emission rate obtained with this
trap was 0.011 gram of lead per mile or a 90 percent
reduction when compared with a production vehicle.
After about 20,000 miles, it was observed that
emission rate compared
with production vehicles.
percent I see Table 1 for
production vehicles I
i [CYCLONE cj : : ; :;
/ Fl
ALUMINA i
PELLETS ]
!r~
d]^7
Q
d
Figure 15. Muffler lead trap type II.
-------
AUTOMOBILE LEAD EMISSIONS
105
TABLE 8 LEAD EMISSION RATE FROM
PRODUCTION VEHICLE WITH
MUFFLER LEAD TRAP TYPE II
Mileage
Vehicle C-83
Emission rate,
grams of lead per mile
Total
Airborne
0
6,000
9,000
12,000
15,000
18,000
21,000
25,000
Average
Reduction in lead
emissions compared
with production vehicles,
percent (see Table 1 for
production vehicles)
0.012
0.014
0.009
0.008
0.006
0.016
0.014
0.011
90
0.021*
0.021*
58*
*Trap filled to capacity with collected lead salts.
particulate lead was being emitted in relatively large
quantities from the tail pipe of the vehicle during high
speed operation. Investigations revealed that the cyclone
collection chambers had become totally filled with the
collected lead salts and that this material was being
re-entrained in the exhaust. An attempt was made to
clean out some of the material in the collection
chambers and the vehicle was then taken to the
Pennsylvania turnpike tunnel for determination of
airborne lead emission rates. The tests in the turnpike
tunnel showed an airborne emission rate of 0.021 gram
per mile or a 58 percent reduction from the production
vehicles. This relatively poor showing in terms of
airborne lead emission rate was due to the fact that
significant quantities of lead were still being re-entrained
from the particle collection chambers and the trap was
simply too full of lead to be fully effective in reducing
the amount of lead emitted from the vehicle.
The Type II trap was disassembled after 25,000 miles
of operation. The alumina pellets were undamaged and
showed no signs of any attrition. The material
accumulated in the cyclone collection chambers was
analyzed and found to contain only trace amounts of
alumina confirming that very little attrition of the
pellets had occurred.
To overcome the problem of re-entrainment of the
collected lead material which had occurred with the
Type II trap another muffler lead trap, designated Type
III, was built. This trap is shown in Figure 16. It was of
— !— 1
.CY£LON
i
, i A ID /v
! PELL
I
1 .
E m
UNA <
ETS I
»-
c
3
LZ
3
Figure 16. Muffler lead trap type III.
the same overall size and shape as the Type II trap but
the internal components had been rearranged to increase
the volume of the particle collection chamber. The flow
path was quite similar to that of the Type II trap; the
exhaust gases flowed first through the bed of alumina
pellets then in parallel through the cyclones and exited
from the plenum chamber. This trap was installed in
place of the production muffler on a vehicle and is
currently under test. Four thousand miles have been
accumulated on the PCD using the Federal mileage
accumulation schedule. The lead emission rate from the
vehicle as determined to date is shown in Table 9.
The total amount of lead emitted as measured by the
total filter averaged 0.010 gram of lead per mile and
compared with the production vehicle the Type III trap
has reduced the total amount of lead by 91 percent. This
vehicle has been tested at the Pennsylvania turnpike
tunnel to determine the airborne lead emission rate and
the value was found to be 0.008 gram of airborne lead
per mile. When this value is compared with the
production vehicles it can be seen that the Type III trap
reduced the airborne lead emission rate by 84 percent.
These preliminary results on the Type III muffler lead
trap are most encouraging. The trap has been designed to
have sufficient collection capacity to hold all the lead
salts emitted from the vehicle for at least 50,000 miles.
TABLE 9 LEAD EMISSION RATE FROM
PRODUCTION VEHICLE WITH
MUFFLER LEAD TRAP TYPE III
Vehicle C-82
Mileage
Emission rate,
grams of lead per mile
2,000
4,000
Average
Reduction in lead
Total
0.009
0.010
0.010
91
Airborne
0.008
0.008
84
emission rate compared
with production vehicles,
percent (see Table 1 for
production vehicles)
-------
106
CYCLING AND CONTROL OF METALS
Further testing of this trap is planned to determine the
reduction in lead emissions over extended mileage and to
determine the ultimate effective life of the trap.
EFFECT OF TRAP SYSTEMS ON ATMOSPHERIC
LEAD LEVELS
From the foregoing discussion it is obvious that the
various trapping systems investigated are quite effective
in reducing the amount of lead emitted from the tail
pipe of vehicles. However, the important question that
must be resolved is whether this reduction in lead
emissions from the tail pipe will translate into a similar
reduction in the amount of lead contained in the
atmosphere. Direct measurements are available to answer
this question and to demonstrate the effectiveness of the
trapping systems. The amounts of lead collected from
the air in the Pennsylvania turnpike tunnel after driving
various vehicles on the road in the tunnel were measured
and the results of these measurements are summarized in
Table 10.
Four different vehicles with production exhaust
systems were run for a total of 13 tests in the
Pennsylvania turnpike tunnel. The air in the tunnel was
sampled, as described earlier, and the average amount of
lead collected on the sampling filter was found to be 101
micrograms. Similarly, three different vehicles equipped
with Trap System C were run for a total of ten tests in
the tunnel. The average amount of lead collected from
the air in the tunnel after running the cars with Trap
System C was 37 micrograms. Comparison of these two
numbers shows that Trap System C reduced the amount
of lead in the air by 64 percent.
Two other vehicles equipped with the duPont total
emission control system, which consists of thermal
reactor and exhaust gas recirculation systems and which
includes Trap System C, were run in the Pennsylvania
turnpike tunnel for a total of six tests. The average
airborne lead collected from the air in the tunnel after
running these vehicles was 29 micrograms and
comparison of this number to that obtained with the
production vehicles shows that the reduction in airborne
lead caused by the installation of the total emission
control system was 71 percent.
One vehicle equipped with muffler lead trap Type III
was run in the tunnel for a total of three tests and the
average amount of airborne lead collected on the
sampling filter was found to be 16 micrograms. Once
again, comparison of this value to the value of 101
micrograms for the production vehicles showed the
reduction of airborne lead caused by the installation of
the Type III muffler lead trap was 84 percent.
It is clear that not only do these trap systems bring
about significant reductions in the total amount of lead
emitted from the tail pipe of vehicles but they are most
effective also in reducing the actual amount of lead
remaining in the air after cars have been driven on the
road in a representative consumer-type driving cycle.
CONCLUSIONS
• Vehicle exhaust particulate lead traps are effective ir.
reducing the total amount of lead emitted from
production vehicles operated on commercial leaded
gasoline by 82 to 91 percent as measured by
laboratory tests.
• Laboratory size-measurement of the emitted lead
particles showed that the traps not only reduced the
large size particles by better than 90 percent, but also
reduced the particles smaller than 0.3 micron (or
particles which are in the same size range as those
found in urban atmosphere) by 71 percent.
• These same lead traps reduced the amount of emitted
airborne lead particles by 64 to 84 percent when
measured in road tests in a vehicular turnpike tunnel.
• Vehicles equipped with lead traps for particulate
control and a gaseous emission control system
consisting of thermal manifold reactor and exhaust gas
TABLE 10 REDUCTION OF AIRBORNE LEAD IN THE PENNSYLVANIA TURNPIKE
TUNNEL DUE TO THE USE OF TRAP SYSTEMS
Exhaust
systems
Production
Trap System C
duPont total
emission control
system (Trap
System C )
Muffler lead trap
type III
No. of No. of
cars tests
4 13
3 10
1 6
1 3
Average*
airborne lead
collected on
filter , /Kg
101
37
29
16
Reduction in airborne
lead,%
64
71
84
•Corrected for differences in total volume of air sampled and ambient air lead levels.
-------
AUTOMOBILE LEAD EMISSIONS
107
recalculation systems, reduced total lead emitted by
85 percent and lead in the air in the vehicular tunnel
was reduced by 71 percent when compared with
production vehicles.
Compact, effective lead traps which incorporate
alumina pellets and cyclone collectors have been
developed which are suitable for replacement of
mufflers on existing cars now on the road.
These lead traps are relatively simple and have no
moving parts. Based on the reported tests, they do not
deteriorate in effectiveness with mileage, require no
maintenance, and should last the life of the vehicle.
ACKNOWLEDGMENTS
The authors wish to acknowledge R. A. Crane, K.
Habibi, and J. M. Pierrard for their contributions to the
data and their helpful interpretations and discussions.
Also, the authors are indebted to L. Chambers, J. G.
Cmorik, K. 0. Koefoed, and T. A. Phillips for some of
the data and information on the performance of the
trap systems.
REFERENCES
1. Environmental Protection Agency, Regulation of
Fuels and Fuel Additives — Lead and Phosphorus
Additives in Motor Gasoline, Federal Register,
37, No. 36, Wednesday, February 23, 1972.
2. Habibi, K., E. S. Jacobs, W. G. Kunz, Jr., and D. L.
Pastell, Characterization and Control of Gaseous
and Particulate Exhaust Emissions From
Vehicles, presented at the Air Pollution Control
Association, West Coat Section, Fifth Technical
Meeting, San Francisco, California, October 8—9,
1970.
3. Ter Haar, G. L., D. L. Lenane, J. N. Hu, and M.
Brandt, Composition, Size, and Control of
Automotive Exhaust Particulates, Journal of Air
Pollution Control Association, 22, 39,1972.
4. Habibi, K., Characterization of Particulate Lead in
Vehicle Exhaust — Experimental Techniques,
Environmental Science and Technology, 4, No.
3, 239-248, March, 1970.
5. Pierrard, J. M. and R. A. Crane, The Effect of
Gasoline Compositional Changes on Atmospheric
Visibility and Soiling, presented to the Society
of Automotive Engineers Automotive
Engineering Congress, Detroit, Michigan, Paper
No. 720253, January 10-14,1972.
6. U. S. Department of Health, Education, and Welfare,
Part II, Control of Air Pollution From New
Motor Vehicles and New Motor Vehicle Engines,
Federal Register 33, No. 2, January, 1968.
7. Robinson, E. and F L. Ludwig, Particle Size
Distribution of Urban Lead Aerosols, Journal
of the Air Pollution Control Association, 17,
664-668, 1967.
8. Lee, R. E., R. K. Patterson, and J. Wagman,
Particle-Size Distribution of Metal Components
in Urban Air, Journal Environmental Science and
Technology, 2, 288-290,1968.
9. Lundgren, D. A., Atmospheric Aerosol Composition
and Concentration as a Function of Particle Size
and of Time, Journal of the Air Pollution
Control Association, 20, 603,1970.
10. Cantwell, E. N., R. A. Hoffman, I. T. Rosenlund,
and S. W. Ross, A Systems Approach to Vehicle
Emission Control, presented to the Society of
Automotive Engineers National Automobile
Engineering Meeting, Detroit, Michigan, Paper
No. 720510, May 22-26,1972.
11. Cantwell, E. N., A Total Exhaust Emission Control
System, presented at the Joint Meeting of the
Ontario and Quebec Chapters of the Air
Pollution Control Association, Montebello,
Quebec, September 20-22,1970.
-------
TRACE ELEMENT EMISSIONS FROM THE
COMBUSTION OF FOSSIL FUELS
J. R. FANCHER
Commonwealth Edison Co.
Chicago, Illinois
THE CONCERNS AND THEIR ORIGINS
Over the last several years there has been a growing
interest in the redistribution, driven or aided by human
actions, of certain elements which are ordinarily referred
to as trace elements. The meaning of the term itself
varies conspicuously with the investigator; that being the
case, it seems appropriate that this paper contain at the
outset a specification of what is meant by that term
when used here. I have taken the liberty of defining
trace elements to exclude:
1. All of the elements which are gasses at ordinary
temperatures and pressures;
2. Nearly all of the elements of generally high crustal
abundance, such as sodium, potassium, magnesium,
aluminum, calcium, phosphorus, sulfur, silicon, and
iron. Arguments can be advanced for retaining some
of these in the trace elements category, example,
because some are trace in a dietary sense, or simply
because their emissions from a particular class of
sources are generally small. However, these ubiquitous
contaminants confront humans and their activities in
such a welter of ways that it is unlikely that any
particular human activity plays a dominant role in
that exposure;
3. Specific compounds or minerals, such as asbestos. It is
fully recognized, however, that no assessment of the
impact of any trace element should be made without
knowledge as to the form in which such element is
manifested; the wide variation in toxicity among the
mercurials, and in particular the recent emergence of
methyl mercury as a major toxic agent, are object
lessons; and, finally,
4. Those elements for which the principal toxic effects
are a result of their radioactive nature. This last
exclusion is made simply in the name of limiting the
subject matter of this paper; I am in no way denying
that such emissions exist nor that there may be
reasonable concern over their effects.
Proceeding, then, from such an exclusionary definition
to the circumstances which have focussed attention on
the remaining trace elements, we find three major forces
have been at work:
1. Multivariate epidemiological studies have occasionally
yielded positive correlations between clinical effects
and atmospheric levels of one or more trace elements;
whether by chance, by joint association, or from
genuine cause-effect relationships. Coupled with this,
an increased interest has developed in the nutritional
value of various trace elements.
2. Researchers in toxicology, concerned, perhaps justly,
over the lack of toxicological corroboration of the
presumed long-term, low-level effects of major air
contaminants such as sulfur dioxide, have quite
naturally returned to examination of known
toxicants, especially the heavy metals.
3. A ground swell of public arousal, some of it probably
carried over from frank poisoning cases involving
either water-borne contamination or ingestion of
lead-based paints, has resulted in regulatory activity
and interest, especially as regards mercury and lead.
Whether or not such action is well-advised, it has
resulted in attempts at emission inventories which go
well beyond those contaminants which have been the
usual objects of suspicion.
The present focus on trace element emissions is at
once the result of direct scientific experiment; of
scientific hunchmanship (which I do not derogate); and
of at least a modicum of public hue and cry, whether for
better or worse.
SOURCES OF TRACE ELEMENTS IN COMBUSTION
SYSTEMS
As indicated earlier, this paper is concerned with a
class of emission sources - combustion sources utilizing
fossil fuels — and carries a special emphasis on large
sources such as electric utility furnaces. The origins for
the trace elements emitted by such sources are obviously
to be found chiefly in their fuels. Moreover, of the three
109
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110
CYCLING AND CONTROL OF METALS
TAB LEI TRACE ELEMENTS IN OILS
Element
Beryllium
Boron
Scandium
Titanium
Vanadium
Chromium
Manganese
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Strontium
Yttrium
Molybdenum
Cadmium
Tin
Barium
Mercury
Lead
Concentration - ppm
.0004
.002
.001
.1
50.
.3
.1
.2
10.
.14
.25
.01
.001
.01
.17
.1
.001
10.
.01
.01
.1
10.
.3
Note: These data sometimes represent only a
single field, and therefore may be either
anomalously high or low.
chief fossil fuel resources, one, natural gas, appears to
have no consequential content of trace elements. I
hasten to add that natural gas is in increasingly short
supply, most especially as a utility fuel, so that its
desirable characteristics are essentially unavailable for
control purposes. Our discussion must therefore
continue to examine the remaining fuels, namely,
petroleum fractions and coal.
Oils
Most utility fuels, like the fuels used for space heating
in small-to-medium-sized residential, commercial, and
industrial furnaces, fall into the classifications of
distillate oils, grade numbers 1 and 2, and residual oils,
grade numbers 5 and 6. A limited amount of crude oil is
also burned without refinement, and the future may see
increased use of intermediate oils, about number 4, or
blends, and perhaps of some fractions beyond residual,
for example, tars or pitch. There are few published data
concerning trace element contents of these various oil
fractions. It is reasonable to conclude that the distillate
oils are probably lower in most trace elements than their
respective crudes, while residuals may well be higher.
Table 1 gives the concentration ranges for various
elements in oil in ppm, as listed by various authors. With
the paucity of data available, it cannot be assumed that
any of these figures are really representative of common
fuels.
One factor which should not be overlooked in
analyzing the impact of oil fuels is the addition of
additives to improve combustion and/or ash collection.
For example, particularly with high-vanadium oils,
additives containing manganese are frequently
incorporated in the fuel as a means of improving
particulate emission control and stack appearance.
Coals
Coals are an almost classic mixture of many
constituents. With respect to trace elements, there is
simply no such animal as a representative coal, even for a
universe as small as a single mine. Moreover, just as
environmental pressures have forced many companies to
essentially abandon coal fuel, only four generating
stations in the East Coast region are not now committed
TABLE 2 TRACE ELEMENTS IN COALS
Element
Beryllium
Boron
Scandium
Titanium
Vanadium
Chromium
Manganese
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Rubidium
Strontium
Yttrium
Molybdenum
Tin
Barium
Mercury
Lead
Concentration— ppm
3
75
5
500
25
10
50
5
15
15
50
7
5
5
3
100
500
10
5
2
500
.01 -.5
25
Note: These data represent only a few samples
each, and therefore may be either
anomalously high or low.
-------
FOSSIL FUEL COMBUSTION
in
to oil fuel; many coal burning facilities have shifted, or
contemplate a shift, to coals quite different than those
intended in their design. The elemental content of these
newer fuels has not been well established. The literature
suggests the range of coal trace element concentrations
which is shown in Table 2. It will be noted that not only
are the concentrations quite different from those for oil
fuel, but indeed a quite different set of elements
predominate.
SINKS FOR TRACE ELEMENTS IN COMBUSTION
SYSTEMS
The above data for oil and coal-fueled power
generation consider only the initial content of trace
elements in the fuels used. Before it can be ascertained
what actual emissions to the atmosphere may result
from use of these fuels, it is necessary to consider what
other routes may be taken by an atom of a particular
element. Figure 1 is a schematic diagram of a large
generating unit. Neglecting deposition of trace elements
upon, or their combination with, the surfaces of the
boiler, ducts, or stack, there are still two possible exits
for their release from the furnace. The first is collection
with the slag, or molten fuel impurities; the second is
passage into the ducts leading toward the stack. The
possibility of significant attrition in the slag is very good,
particularly for coal-fired furnaces; it is well established
that of the ash normally present in coals, at least 20
percent and often as much as 80 percent, is retained as
slag in modern furnaces. There is, therefore, a reasonable
chance that trace elements will be entrained in, or will
combine with, such a slag flow and will, therefore, be
prevented from reaching an air emission site.
The remaining releases ordinarily face a second barrier
before they may exit the plant. That barrier is in the
form of pollution control equipment, a feature of most
utility installations since the late 1920's. There are at
least four types of pollution control equipment in use or
under construction for utilities today: Mechanical
collectors; electrostatic precipitators; baghouses; and
scrubbers. All of these devices are aimed principally at
reducing the emissions of particulates; therefore, they
are generally effective if the material to be collected is in
a condensed or combined form as it passes through the
control equipment. Each type of control equipment has
its own characteristics, which deserve some comment
individually.
Mechanical Collectors
Mechanical collection, known also as cyclone or
multiclone collection or under various other trade
names, utilizes centrifugal separation of particles from
the gas streams which carry them. The collection is
obviously dependent upon the size and density of the
POSITIONS 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13,
WATER TREATMENT
LAKE SIDE
INTAKE
LAKE SIDE
DISCHARGE
Figure 1. Unit 2—3 systems.
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112
CYCLING AND CONTROL OF METALS
particles. Cyclones have been popular on small
industrial-size boilers; for stoker firing, which produces a
high fraction of large particulate; and for oil firing.
Collection efficiencies in the range of 70 to 80 percent
are readily achieved; higher efficiencies are often claimed
and may be achieved on certain kinds of particulate, or
where dust loadings at the control equipment inlet are
extremely high. Changes in the type of fuel, even though
the apparent fuel parameters do not change, may alter
the collection pattern drastically; for example, it is
reported that the Venezuelan-based residual oils are less
satisfactory with such controls than the domestic and
Middle Eastern oils.
Electrostatic Pretipitators
These devices have been the technology of choice for
many years on pulverized coal-fired and cyclone-fired
boilers. Design efficiencies range from about 88 to
beyond 99 percent. Some use of electrostatic collection
has also occurred for both residual and distillate oils. In
both mechanical and electrostatic precipitators the gas
temperature in the control device is typically 250 to 350
F, although a new type of precipitator, the hot
precipitator, has recently been introduced, which
functions in ambient temperatures of 800 to 1000 F. It
is ordinarily placed in the gas stream ahead of the air
much more efficient for large particles, but we have not
seen substantiation of that either in the literature nor in
our own experience.
Baghouses
Bag filters have been used experimentally on oil-fired
furnaces and one is now being constructed for a
medium-sized coal-fired unit. Bag lifetime is a difficult
operating problem. To my knowledge, no one has
run tests on bag filter efficiency for these purposes;
it is widely assumed to be very high. Gas temp-
peratures must be held above the dew pointto avoid
acid attack.
Scrubbers
Some scrubbers have been built for particulate control
on coal and oil-fired units. Recently there has been an
upsurge in interest because of the potential for sulfur
(and perhaps nitrogen) oxide removal. It has been
hypothesized that scrubbers might also accumulate trace
elements such as mercury. Again, that has not been
established.
CASE STUDY: MERCURY
Of the trace elements, mercury has received, by far,
the most attention. As a result of the obvious public
interest in this contaminant, Commonwealth Edison
engaged Swanson Environmental Consultants, Inc. of
Farmington. Michigan, to do a mercury mass balance
analysis on our State Line Generating Station in
Hammond, Indiana. This study was completed during
January of 1971. As has been reported for other similar
studies, it was not possible to achieve an accurate mass
balance, probably due to the very low concentrations
involved and the particularly difficult determination of
the average level of mercury in the coal. Nonetheless, the
results are somewhat illuminating, as shown in Table 3.
Stated simply, our conclusions are as follow: Essentially
all the mercury enters in the fuel itself; while some
concentration takes place in slag and ash, the loss of
mercury to these sinks is negligible, and apparently most
of the mercury is emitted from the stack.
TABLE 3 GENERAL RESULTS OF MERCURY
BALANCE ON A COAL-FIRED
GENERATING STATION
Mercury input:
Fuel
Air, water, etc.
Mercury output in:
Slag
Precipitated ash
Unprecipitated ash
Flue gas
Water, etc.
Apparent error in balance
100 %
Negligible
4.5%
4.8%
.1%
78 %
Negligible
87.4%
12.6%
100 %
Analytical method for most measurements: Atomic
Absorption.
I hasten to add that mercury may not be, probably is
not, representative of other trace elements. For example,
the boiling point of the elemental metal is 357 C or
about 685 F; a temperature that is easily possible within
the flue gas stream. Few other trace elements are in that
range. Thus, metallic mercury might pass through
electrostatic precipitators in vapor form, while any trace
elements solidifying might be trapped by control
equipment. This is merely hypothesis at present; but its
application may have important consequences for future
control strategies.
IMPACT OF FUEL COMBUSTION EMISSIONS
It would be easy, given the figures of my previous
tables, to extend the calculations to the number of
pounds of each element per day, per month, or per year
emitted by any one source or combination of sources.
Some authors have, in fact, done exactly that. Such an
exercise yields heat without illumination; it is
reprehensible for two reasons. The first, which I have
already remarked, is the unknown chemical and physical
form of these emissions; essential to any understanding
of their biological significance. I must add that emissions
from large combustion sources, such as power generating
-------
FOSSIL FUEL COMBUSTION
113
facilities, are apt to be strongly bound inorganic
compounds, mixtures, and alloys. Organic compounds
are quite unlikely outcomes of such oxidizing,
high-temperature, low-carbon environments. Conversely,
small-scale combustion of fuels, incineration, heating,
and mobile sources may result in reactive and complex
compounds.
Secondly, the lessons of air quality prediction learned
on other battlefields include the pre-eminent role of
micrometeorological factors: source stack height, gas
flow, gas temperature, particle size, and atmospheric
stability and wind parameters. The large sources may
not, and probably do not, constitute the most important
contributors to general ambient air quality. Failure to
consider these factors may result in encouraging small,
reactive, poorly distributed emission sources while
penalizing large, controllable ones. I should not need to
belabor that lesson; the consequences of not learning it
could redound to the detriment of millions of people.
RESEARCH NEEDED AND IN PROGRESS
Obviously, one set of important facts not yet known is
the behavior of trace elements in combustion systems.
How much of element E is captured in the slag? How
much in precipitated fly ash? In what chemical form
does element E appear, oxide, sulfide, what? These
questions, and related ones, are the subject of a project
to begin shortly here at Batelle-Columbus under the
sponsorship of the Edison Electric Institute; the trade
association for the private electric utility industry.
Another set of data which is of interest concerns the
transport and fate of trace element contaminants in
urban atmospheres. New York University is studying this
subject, under the sponsorship of Edison Electric
Institute and the American Petroleum Institute. This
study includes analysis of deposition in human lung
tissue, as well as study of samples of suspended
particulate from several New York City locations.
Finally, United States Environmental Protection
Agency and various agencies around the county have
programs in the works to determine the trace element
content of a variety of fuels, so that more accurate
assessmentof, at least, the fuel combustion input can be
made.
CONCLUSIONS
A variety of kinds of data are thus accumulating
toward knowledge of the movements of trace elements,
with and without the assistance of man. The facts as of
this date are these:
1. Trace element emissions from combustion systems
cannot yet be readily quantified.
2. The effects of current levels of airborne trace
elements on health and welfare are not yet known,
but there is little reliable evidence of critical
association and essentially none of causation.
3. Our mandate, therefore, is to seek knowledge about
effects, mechanisms, emission sources, and controls,
so that intelligent and objective decisions can be
made. Emotion is to be eschewed: An attack on an
unknown enemy may exact a dear price without
commensurate gain.
BIBLIOGRAPHY
l.Bertine, K. K. and E. D. Goldberg, Fossil Fuel
Combustion and the Major Sedimentary Cycle,
Science 173, pp. 233-235, July 16,1971.
2. Joensuu, 0. I., Fossil Fuels as a Source of Mercury
Pollution, Science 172, pp. 1027-1028, June 4,
1971.
3. Billings, C. E. and W. R. Matson, Mercury Emissions
From Coal Combustion, Science 176, pp.
1232-1233, June 16,1972.
4. Ruch, R. R., H. J. Gluskoter, and E. J. Kennedy,
Mercury Content of Illinois Coals, Environmental
Geology Note Number 43, Illinois State Geological
Survey, Urbana, Illinois, February 1971.
5. Hammon, A. L., Mercury in the Environment, Natural
and Human Factors, Science 171, pp. 788—789,
February 26,1971.
6. Bailey, E. H, P. D. Snavely, Jr., and D. E. White,
Chemical Analysis of Brines and Crude Oil, Cymric
Field, Kern County, California, Short Papers in the
Geologic and Hydrologic Sciences, 398, USGS, pp.
D306-D309.
7. Mercury Emission Study, State Line Generating
Station, Unpublished report for Commonwealth
Edison Company by Swanson Environmental
Consultants, Inc., 1971.
8. Mitsch, W. J., The Significance of Mercury in the
Atmosphere, Unpublished paper, Florida
University, November 24,1971.
-------
LUNCHEON ADDRESS
Martin Lang
Commissioner of Water Resources
-------
LUNCHEON ADDRESS
MARTIN LANG
Commissioner of Water Resources
City of New York, New York
As a career civil servant, I've spent some 30 years in
the city. I admit that some of those years have been very
odd; but you know, here in the heartland or America I
have detected the presence of a kind of urbanphobia, or
an irrational fear that is triggered whenever New York
City is mentioned. Really, New York is no different
from Columbus or Cincinnati or Chicago. It's just that in
the pressure cooker of that city, things tend to happen
sooner, and perhaps to a more intense degree, than
anywhere else. Actually, what happens in New York is
just a portent of things to come in all the other
megalopolitan areas across the country. But today I'd
like to point out that in one area at least — the area of
water pollution control — I think that New York City
stands ahead of all other coastal cities in the world, and
ahead of many inland cities as well.
A statement like that may surprise many of you, but
let me take a few moments to tell you a little about the
Department of Water Resources and our commitment
to impounding, protecting, and distributing to every
citizen of the city (and to some of the surrounding
counties, too) an ample supply of the best potable water
in the world. I am charged with gathering up that
slightly used water supply, conveying it away from the
people's doorsteps, and treating and discharging it to the
peripheral waters of the city in such a way as to keep it
innocuous. Now that means that my department is
responsible for the construction, operation, and
maintenance of all water supply facilities. We are also in
charge of the design, construction, operation, and
maintenance of all water pollution control facilities
(including the interceptors and a fleet of five ocean
going sludge vessels); and the design, construction, and
maintenance of all the sewers in the city. I have 6,000
miles of water mains (some of them well over 100 years
old) and 6,000 miles of sewers. Sometimes I feel that
each mile is draped like an albatross around my neck.
But I feel fortunate to be in a city that as early as 1920
began to put their money where their convictions were.
And I feel fortunate to be in a city where the present
mayor is a real champion of the urban environment and
has put his money where his convictions are in that
respect.
In New York City there are various kinds of budgets.
There is the capital budget, the expense budget, and the
work performance budget. Then, following the Federal
lead, we are trying to introduce something called the
Program Planning Budget. The value of this system is
that it makes you define what you're doing in terms of
your actual mission. My mission in water pollution
control is not specifically to treat sewage. No, my
mission is to protect and enhance the marine
environment; to protect and enhance the receiving
waters. When you look at it that way, your attitude
toward everything changes. To me, the important issue is
no longer the development of technical minutiae that
you can control. All our sophisticated techniques for
removing metals — sulfide precipitation, reverse osmosis,
electrophoresis, electrodialysis, etc. — are useless if we
can't face up to the real issue of how to dispose of the
end product. Now that I have this sludge, now that I've
dried it, now that I have it as a hydroxide slurry, what
do I do with it? That's a little tougher. I could go on at
great length and tell you all about the activated sludge
process and some of the innovations we have made in it.
I could tell you all about mixed sludge thickening,
interstage elutriation, high rate digestion, and all the
various modifications of the activated sludge process in
which my department has had some innovative input.
But that would be evading the real issue, which is what
happens in the receiving waters. The payoff in all our
efforts is what actually happens in the environment. The
environment doesn't know percentage removal. Every
drop of water in our bay and harbors only knows its
immediate microenvironment and the load on it. It
knows nothing about percent BOD removal.
Until that day when we can take the wastes of
mankind to where the tectonic plates override the ocean
deeps and reincorporate them into the magma of the
earth, we have only three options for waste disposal. The
three ultimate dumps for everything are the air, the
water, and the land. You all saw a chart this morning
115
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116
CYCLING AND CONTROL OF METALS
that neatly channeled waste in four directions. The end
products in this case all got off the flow chart, but they
are still part of the environment, and we must consider
the total impact they will have on that environment.
I am a practicing ecologist and environmentalist, and I
say that with all due modesty. You have attended many
environmental conferences, and many of you have read
about the fragile ecosystems of the tundra, the savannah,
the rain forest, the estuary, and the desert. We are all
concerned about the buildup of DDT in the body fat of
the Antarctic penguin, the extinction of the blue whale,
the necessity of preserving the California condor, and
the fragility of the eggs of the peregrine falcon because
of pesticide buildups. I believe in all that and I've
worked to abate these blights on our environment. More
particularly I am concerned about another fragile
ecosystem — the urban ecosystem, where eight million
agitated people are penned up in 300 square miles of
land. I am charged with the two precious life support
systems for this fragile urban ecosystem: the water
supply and the used water supply.
In the area of ecology there are many self-appointed
and self-anointed prophets of doom who say the sky is
falling. Their favorite term is "irreversible damage." I am
pleased now to give you some report on this with respect
to New York City and to give you some supporting data
for the statement I made earlier that New York stands
ahead of all other coastal cities in the world in the area
of water pollution control.
New York City is fortunate to have base line data on a
harbor survey going back to 1909. It's too bad we don't
have such similar data for all our waters. We don't know
what the lead was along the highways in 1910 or what
the mercury content of fish was. You know,
environmental base line data are very important because
they sometimes enable us to discern between long-term,
natural, cyclical changes and manmade changes in the
environment. But at least in our harbor we have that
data and it shows the degradation of our estuary waters
in the years between 1912 and 1917.
And then something happened in the City of New
York that maligned city that always invokes a little
snicker. The people of the City of New York started to
put their money where their convictions were. In the
1920's the City began to build a series of secondary
treatment plant; - on salt water mind you, not on a
potable water shed, not on inland fresh water, but on a
tidal salt water estuary. And they did it during the
depression. Interrupted by World War II, they plowed
anead. At present they are treating 1.1 billion gallons a
day of our waste water supply by secondary treatment.
We still have some raw discharges, but 1 have initiated a
SI.5 billion program for the upgrading and expansion of
all of our plants and the creation of two huge new super
plants in the city, one of which (the North River Plant)
is under construction today. The avowed intent is that
by the end of this decade we will treat all the dry
weather waste water flow of the City of New York to
+90 percent BOD and suspended solids removal.
Incidentally, New York City has addressed itself to what
might seem to some of you a very quixotic enterprise
(but I assure you that it is not). In the latter half of the
20th century we're going to restore bathing beaches
already abandoned and create new bathing beaches in
the heart of megalopolis in Jamaica Bay. I have the first
such prototype plant on stream right now in Jamaica
Bay, the Spring Creek Plant, which is designed to take
care of the combined overflows that are a problem for
many of the coastal cities.
Now with all this kind of activity, we're not
complacent at all. The people of the city have a right to
ask what we are getting for all our efforts. By that very
sensitive parameter of dissolved oxygen (DO), New York
City can show that today, in 1972, we have raised the
dissolved oxygen level to a point not seen since the early
years of this century. I repeat, we have dragged up the
DO of all the major branches of the harbor to a level not
seen since about 1910 or 1912. And we're doing that
while carrying on our backs, so to speak, the discharge
from our neighboring state, New Jersey.
Those of you who are familiar with New York can
remember the best nickel's work in the city — a ride on
the Staten Island Ferry. It was a cheap date to take a girl
for a ride from the Battery to Staten Island along the
upper bay there, to stand up on the bow and say "Oh,
what salt spray." You were going through the dispersion
field of the Passaic Valley, which disperses slightly less
than 300 million gallons of sewage a day — sewage that
is twice the strength of New York City sewage and not
disinfected. But remember what I said: the marine
environment only knows the load. It doesn't know
percentage removal. It doesn't know what is being taken
out; it only knows what is being added to it. Now that
we can see this, there is some light on the horizon. And
now that New Jersey is beginning to follow our example,
I can assure you that our inshore estuarine waters will
come to a level within the next decade and a half not
seen in the memory of living man.
So, while all the prophets of disaster are just talking,
some of the engineers are doing something about it. You
know, you're not going to do anything to the
environment with rhetoric. You're going to do it with
plans, with engineering, and with hardware. You're going
to do it with trained men and designs. Mere talk is not
going to do anything; we've gone past the talking stage.
Now this brings me to metals. New York City's
program was based on the digestion of sludge and the
marine disposal of that sludge at the approved point
offshore under permit approval of the Corps of
Engineers. In 1957, I was the first organizer. I wrote the
industrial waste regulations of the City of New York,
and I saw them through until they became law and until
we set up an industrial waste section (which has been
growing ever since). This industrial waste control was
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LUNCHEON ADDRESS
117
divided into two parts. First, the city levied a surcharge
to cover a proportionate share of the extra cost of
treating approved wastes of high strengths. Second,
certain wastes - toxic, dangerous, inflammable,
explosive, or obstructive material — were prohibited
from the city sewers. And of course, metals and cyanide
and oils figured in that.
At this point I would like to say that we should not be
so parochial as to sit here with blinders on and address
ourselves only to trace metals. When you talk about
environmental impact you should also consider the
refractory organic compounds, which may have very
insidious effects or may have synergistic effects because
of organometallic compounds. However, we did organize
and implement this program, and we were the first
coastal city to do so.
As a reward for all our diligence, we found ourselves
summoned by the United States Environmental
Protection Agency and by some zealous Federal
attorneys only a few months ago to appear before the
bar of justice and account for our dilatory inaction. The
thesis of the Federal attorney was that I must be some
kind of shambling Neanderthal who needed to be
dragged into the 20th century. Didn't I know about the
effects of mercury and cadmium? Didn't I know?
Yes, I do know. I have been in close association with
Dr. Michitaka Kaino of Tokyo who fought the famous
Minimata case. Just a year ago I stood on the streets of
Osaka, Japan, carrying a picket sign along with the
students to protest the cadmium discharges that led to
the Itai Itai disease. The Federal attorneys wanted me to
be aware of the impact of metals, and they wanted our
requirements regarding them to be even more rigorous
than the Federal Government's. I am a very pragmatic
person. Life is not that simple. I have appealed publicly
and I am doing so now; but now I know the Federal
Government is going to act. For years we have been
saying, let the Federal Government set standards for
toxic materials throughout the country on an equitable
basis and rational basis. We will rigorously enforce them
for the wet industries in New York City. I don't want
them to be able to move 2 miles away across the Hudson
River and take refuge there. There should be no place to
hide. These standards should be leveled across the board.
The new law for which Congress overrode the President's
veto calls for just such promulgations of standards, and
we're eagerly awaiting them.
Meanwhile, we have moved vigorously. At a time of
austerity in the city, Mayor Lindsay gave me an
additional staff, an additional special task force of one
ot my industrial waste sections of 15 people with the
vehicles and the laboratory support and the ancillary
clerical support — just to concentrate on intensive
policing of metals discharges. Now being an engineer, I
am enamored of numbers. Much of the talk about this
problem has involved emotion and hysteria rather than
real figures.
For example, the specter has been raised that by
marine sludge disposal we are creating a dead sea
offshore, and that this dead sea was discharging a terrific
concentration of metals. If you look at the real figures
you will find that dredge spoils and construction debris
were actually contributing more metals than the sludge.
You would also find that the ambient waters in and
around New York City had metals concentrations that
were lower than those for the United States Public
Health Service drinking water standards. It is very
significant that the sludge itself is highly visible.
Well-digested sludge is a black, tarry fluid - a viscous
fluid. It's much more highly visible than the
well-dispersed effluents in the inshore receiving waters.
But one discharge from New Jersey, in our Upper Bay,
right within spitting distance of downtown Manhattan,
has six and one-half times as much BOD as all the BOD
of our sludge discharged offshore and with tenfold more
metals right inshore. I think it was a reasonable, rational
judgment to move the discharge offshore and protect the
precious inshore estuarine environment. That's the
classical spawning ground of the marine biota. That's the
area through which the anadromous fish move as they go
up the Hudson. I think that judgment is paying off for
us in the restoration of our inshore estuarine precious
dissolved oxygen. In studying the metals, however, I
wanted to know the actual mass balance of the metals,
the quantitative movement.
There was some simplistic reasoning: just nail the
electroplaters and you have solved the problem. New
York City is not a big wet industry town, but we have
about 200 electroplaters. We have sampled every one of
them. When I say samples I don't mean grab samples; I
mean around-the-clock samples, seasonal sampling to go
through all the cyclic and seasonal changes. We have a
pretty good fix on their discharges. But I wanted to go
one step further. I do a lot of other industrial waste
analyses, and I have now started a new procedure..If my
men are analyzing fat rendering plants, fish smoking
plants, or textile processing plants, they also do analyses
for metals to get an idea of the total metal output of all
industries and not just those classically associated with
metals. I have also prepared charts showing the hierarchy
of metals of various big cities in the United States. There
is one that really interests me, and that is Grand Rapids,
Michigan. It stands head and shoulders above everybody
else.
I am trying to get figures on the metals problem so we
can make rational decisions where to concentrate our
efforts. We have nailed the electroplaters right now.
Currently I have in my hand about 80 stipulations from
the electroplaters that are being implemented; the rest
are being summoned, many each week. We are going to
bring them into line, and it has already had a profound
effect.
However, when you look at all the sources of metals in
megalopolis (and I have a very good way of finding them
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CYCLING AND CONTROL OF METALS
1 just checked the effluent to my treatment plants)
you find some very interesting things. I'd like to nail the
culprit, for example, who puts in one-fifth of all the
copper coming out of New York City. By now you don't
want to hear that trite cliche from Pogo, "We met the
enemy and he's us." You've heard that. But I met the
enemy; it was me. I account for 22 percent of the
copper in the water supply (and hence the sewage) by
the copper sulfate that I add in the upstate reservoirs for
algae control, and I will continue to do so. I find there is
also a measurable amount of zinc in the water supply.
You say it isn't much, but we do consume 1.35 billion
gallons of water each day in New York City. So if you
want to express it in terms of pounds, it would be
substantial - as much as 350 pounds of copper.
I proceeded to look even further for sources of metal
around our city. I am familial with the lead emissions —
you know, with all that lead that's emitted and
solubilized and that Dr. Jacobs hasn't taken care of yet.
Where does it go? It is eventually flushed along into a
catch basin, into the sewer, and into our treatment
plant. Eventually some of it that's not precipitated is
going to go out into the receiving waters. They don't
have to worry about the stack emissions. Dr. Francis
says don't worry, it's 10 ppb not ppm (you know
mercury). But all of this is going to get caught by the
rainfall and all of it's going to wind up in the receiving
waters.
Then I thought of something else. If you look around
the city, whether it's New York City or Columbus, Ohio,
you will see some corroding car bodies. You look at
some galvanized fences and you say that the galvanizing
looks a little gray now. What happened to the zinc?
Where did it go? It's been solubilized. Where's it going to
wind up? It didn't evaporate. It's going to wind up right
down in the sewer and eventually in the sewage
treatment plant and in our receiving waters. I tried to
explain this once to a Corporation Counsel of the City
of New York — you know, a very conservative
individual, a former Solicitor General of the United
States. I was trying to tell him about the amphoteric
nature of zinc and particularly aluminum. I tried to
explain what an amphoteric metal was, but I wasn't
getting through. I tried to point out how these things
always wind up in the sewers. "You know, Mr.
Counselor." I said, "it's kind of a gay metal that can
swing either way." And someone brought the story back
to Mayor Lindsay that I was affronting the dignity of his
Corporation Counsel. But since he had to take care of
the Times Square phenomena, I figured he knew what I
was talking about. So you see the galvanizing metals and
the corroding facades.
Then I looked at an Assistant Federal Attorney from
the Southern District of New York and said to him,
"You sir are a polluter and you are a contributor of
metals." He replied, "I don't run an electroplating
plant." "Mr. Attorney." I said, "do you own your own
home?" He replied, "Yes." I asked, "Alter a while, do
you find that you ever have to replace the faucets? Do
you find that the sink strainer gets a little corroded after
a few years?" He said, "Yeah, yeah." I then asked,
"What do you think happened to that corrosion? Do
you ever polish anything in your workshop basement?"
He answered, "Oh sure, I'm very handy." I said, "What
do you think happened to that metal you abraded? Do
you ever use any compounds that contain metallic salts
you know? Do you know what's in a pharmaceutical
compound or medicines you use?" You know, just
broken thermometers alone going down the sewers from
some bathroom can account for substantial amounts of
mercury.
I began to get an idea that sheer residential areas -
just people — most of themselves generate metals. So I
sent my industrial waste team out to different areas of
the city. I knew the industrial areas; I was sampling their
wastes. So I sampled areas of one- and two-family homes
and modest apartment houses. I went to a big, purely
housing complex like Co-op City in the Bronx, and I
sampled that. And do you know what I am beginning to
find out? I'm going to publish this within a year or so
because I keep accumulating data, but I am pleased to
tell you now that just like Pogo says, "You and I are in
this too, you know."
Without letting up in our relentless quest to get the
wet industries to conform, let us just address ourselves
to what sheer metropolitan living does. Purely residential
areas, and these are just round figures, account for about
33 percent of the copper, 38 percent of the nickel, 23
percent of the zinc, and 57 percent of the cadmium in
New York City. Now that may differ in other industrial
areas, because New York City is neither a big heavy
industry town, nor a big wet industry town. In the
classic small town situation, one big plant dominates the
town — one big wet industry whose population is larger
than that of the entire town.
These figures will change. But since this country is
increasingly urbanized, and since these urbs become
"slurbs" and suburbs and then coalesce irsto
megalopolises, we should address ourselves to the sheer
output of domestic residential living. I invite you to do
so at your next symposium, when we talk about what
comes out of the automobile and the strip mines (there
are no strip mines in New York, to my intense regret; it
would solve one tremendous problem of solid waste if
there were). When you talk about the sources of metals
in our environment, I invite you to consider the source
of pure people, and their daily activities. We're great
consumers. We are consumers of goods, we are abraders
and corroders and users of goods that eventually become
soluble metals.
I have been analyzing the metals in the sludge, and I've
been talking with the President's Advisory Committee
and with CEQ about it. But the truth is that sludge
disposal is just another aspect of solid waste disposal.
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119
Anyone here who has a viable solution to the solid waste
disposal of any major metropolis has also created a
viable solution for the sludge, because the sludge can be
merely a top dressing that can ride piggyback on the
solid waste. New York City generates up to 30,000 tons
a day of refuse, and you know, we're pretty good; we
know how to pick it up. But when you pick it up,
you've got to set it down somewhere. Everybody wants
you to pick it up; nobody wants you to set it down. You
all read the environmental journals. Aren't you
enamored of returning the organics to the soil?
We're trying desperately to do something. I have used
every cubic foot of digested sludge that I could put on
completed sanitary landfills to create park area. We've
got a beautiful golf course in New York City created on
completed, compacted fill and digested sludge (which
acts as a synthetic humus, like a topsoil binder). It's not
a complete topsoil, and it's not a complete fertilizer; but
it can create synthetic topsoil. Nevertheless, we still have
the problem of where to set it down. We don't have strip
mines, we don't have barren lands, and we don't have
any big arroyos or gulches or deserts. We are appealing
to the Federal Government: the solution for solid waste
disposal transcends narrow political and geographical
boundaries. The Federal presence must be felt. We can't
go to Chicago as a solution, where there is a man who
very complacently says he has solved that problem. He
bought 14,000 acres 200 miles from Chicago. It's
costing him about $100 per ton (it cost me $12 per
ton). He is willing to pay the price; the only thing is, he
needs another 50 or 60 thousand acres. If we were to use
the Chicago technique, I'd take a good part of
southeastern New York State and make it our dump
area. And we are talking about sludge only, here.
So obviously the Federal presence must be felt. When
the environmentalists ask if you don't want to return the
organics to land, my answer is yes, but give me the land.
And when we do return the organics to the land, do you
know what the Federal EPA says? They say, "Hey wait a
minute, fellow. What about that metal burden in there?
It's going to leach out, and then what are you going to
do?" Irreversible economic ecological damage. We are
back to that again; we just toss it from one hand to the
other. The options are very limited, and probably the
most effective thing to do is to get the metals at the
source before they get in. After all, sewage is just slightly
used water; that's all it is. The average strength in New
York City's sewage is 150 ppm of suspended solids and
BOD. That means you've got to work on a million
pounds to handle 150 pounds of solids. And if you get
the metals concentration down in a fractional ppm
range, you'll have to work on hundreds of millions of
pounds to work on a fraction of a pound of cadmium or
zinc or hexavalent chromium. Therefore, it's easier to
get it at the source.
I am just going to leave this one thought with you. It's
almost presumptuous of me to talk about metals to this
vast array of talent here and to tell you these obvious
truisms. But each of you interact with a Federal agency;
some of you are a part of a Federal or State agency. My
appeal to you is this: that decisions should be made on
rational numbers, not on that nice round figure of zero.
Because, you know, that's just a nice goal. Consideration
should be given to the normal ambient level of metals in
receiving waters. Somebody just mentioned a word
about vanadium; but I remember reading about 10 years
ago in the Scientific American that vanadium plays an
important part in the life cycle of sea salps. We know
that there are normal metal concentrations in the
ambient waters. Our effluent standard should be geared
to some rationale, with full knowledge that there may be
synergistic effects, with full knowledge that discharge
into estuarine waters may permit shellfish to concentrate
metals.
I have touched a number of bases, but I want to
emphasize two things. First, there are many inputs to
our environment besides strip mines, electroplaters, and
wet industries. One such input is sheer metropolitan
living itself. Second, I think we should be in an intense
data gathering situation now to determine the base line
data of our environment of metals. In that way, we can
make judgments on the basis of real figures rather than
on hysterical emotion.
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SESSION IV
MONITORING FOR TRACE METALS IN
THE ENVIRONMENT
Chairman:
R. Rabin
National Science Foundation
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MONITORING SESSION -
CHAIRMAN'S OPENING REMARKS
R. RABIN
National Science Foundation
Washington, D. C.
Concern for the health of man and his global
life-support system has spawned an era of ecological
logorrhea, the nucleus of which is the term pollution.
However confusing and inconclusive the debate,
collective public opinion on pollution is easily formed
when the senses are directly affected. And when
pollutant concentrations are sufficiently high and
resultant damaging effects are readily perceived, the
impacted population may obtain redress given the
motivation and needed legal instruments. Of course, this
represents an extreme; the tip of the pollution iceberg.
In the present social climate, which encourages a more
thorough and scholarly assessment of man's activities
and their environmental consequences, we face new
realities. These relate to the quintessential and vexing
question of how one scientifically and legally defines a
pollutant or contaminant. Although other considerations
subserve this question, they too must be examined. For
examples:
A. Very often the substance is only detectable in
trace concentrations, i.e. at levels of micrograms or less
per gram or per liter. Analytical methods to separate the
contaminant from complex mixtures, identify and
measure it are time consuming and expensive. Even
state-of-the-art methods may be relatively insensitive or
inaccurate, and rely on trouble-prone instrumentation.
There may be inadequate standard reference materials
against which the suitability of a method can be
calibrated. Improper sampling and sample handling and
storage may introduce substantial errors into the data
output.
B. In natural habitats the toxicity of a contaminant
may be expressed so subtly that months, possibly years,
may elapse before ecological perturbations are evident.
Thus, the consequences of threshold effects are no less
important to the population ecologist than they are to
the biochemist or toxicologist. They eventually relate to
the elasticity of biotic communities, i.e. their ability to
withstand irreparable harm from assault on their most
sensitive members. Spatial considerations in the
contaminant-target relationship also complicate matters
since accumulation and toxicity may be perceived far
downstream or downwind from the point of release.
C. The cause and effect association between
compound and target apparent in the field may originate
with a parent compound whose structure and properties
have changed during transport. The evolution of
peroxyacetyl nitrate (PAN) in smog by photolysis, and
the methylation of inorganic mercurials are well-known
examples. In both cases the end products are more toxic
than their progenitors. We recognize with increasing
clarity and frequency that knowing only the value for
total mercury or cadmium (or whatever element) is not
enough; quantifying the biologically active form may be
essential.
D. Transport processes themselves are imposingly
complex. Much of the tetraethyl lead in gasoline, for
example, is emitted in auto exhaust as lead
chlorobromide in a population of particulates varying
from a micron or less to those much larger in size. Larger
particles settle quickly along the roadside in suburban
and rural areas. Soil cores, vegetation, and rodents show
concentrations of lead diminishing from up to 1000
parts per million (ppm) at the source to a background
level of about 20 ppm at a distance of 50 to 100 meters.
Collectively, data indicate that man's best natural
protection against rurally vented lead is soil, which in its
capacity as a vast ion exchange resin, tenaciously
chelates the metal under common conditions. But the
fine (submicron) particulates are subject to myriad
meteorological and climatic variables which have
prevented easy development of satisfactory air transport
models from line source pollution. In urban areas, where
such information is so badly needed, and the
soil-to-concrete ratio is much smaller, the movement
patterns of lead are largely unknown. Street dust is
suspected to be an important reservoir for atmospheric
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CYCLING AND CONTROL OF METALS
reinjection and for storm drain-carried lead. From the
latter, lead may be partitioned between sludge after
sewage treatment, and rivers and streams in both soluble
and sediment bound states. Zoologists at the University
of Illinois have shown that bloodworms inhabiting
sediments near the water-sediment interface are avid
concentrators of the metal perhaps constituting an
important link in lead transport in aquatic food chains.
Aquatic biologists at the University of Missouri, Rolla,
and the University of Colorado have found that algae in
streams receiving effluents from metals mining and
milling operations concentrate trace metals in the range
of hundreds to thousands of ppm.
E. The signal-to-noise ratio in engineering parlance is
also applicable to the study of trace contamination.
Unless background levels contributed by volcanism, rock
weathering, soil formation and breakdown, and other
natural processes are accounted for, the importance of
some human contributions may be overemphasized.
While the environmental release of cadmium seems
almost entirely man's doing, perhaps more than 50
percent of circulating global mercury is a consequence of
a complex natural cycle. Geographical medicine is a field
of study which relates natural excesses and deficiencies
of elements to human and animal diseases. Its potential
to contribute insights to the signal-to-noise enigma could
be more fully utilized.
F. The scientific aspects alone of metal contaminant
research problems require expertise in many disciplines.
The research team approach, beside demanding
individual scholarship, needs dynamic management. In
the university milieu the traditional disciplinary and
departmental organization may impair the formation
and function of interdisciplinary amalgams. That they
do exist and are performing productively, however,
severely tests the pessimists' hasty generalizations of
several years ago. Perhaps even more important is the
fact that universities haven't found it necessary to scrap
and rebuild their structures to accomplish this.
The principal concerns of the scientific community
are, as I see them:
1. Determining the levels of potentially or overtly toxic
substances in the environment;
2. Assessing the effects of these levels on man, animal,
and plant communities;
3. Relating these findings to methods of control.
To address these concerns I recognize research
opportunities in that:
1. Toxic or hazardous substances must be separated
from complex mixtures, identified and measured, or
analyzed in situ;
2. The movement of contaminants and their rates of
flow through environmental media must be traced
from their sources to ultimate deposition sites;
3. Target organisms along, and at the end of, the routes
of flow and their sensitivity to noxious agents must be
determined;
4. The complex relationships between biotic
communities and the effects of the biologically
available toxicants must be understood;
5. Research results should suggest improved monitoring
systems and, when warranted, ultimately aid in
devising technological, legal, and economic abatement
or control measures.
When considering which contaminants merit our
attention, I suggest that we contemplate the following
aspects:
1. Intrinsic biological risk;
2. Geographical dispersion;
3. Quantity and persistence in the environment;
4. A presumptive tendency to accumulate in the food
sources of man and other biota; and
5. Difficulty of avoidance based on extant use patterns
and current technology.
Research and monitoring is anchored in analytical
methodology. The perception and measurement of
contaminants in biota and environmental media,
particularly in trace concentrations, form the common
denominator relating levels, effects, and efficacy of
instituted controls. Analysis in no less critical to the
researcher than to the monitor, standard setter, polluter
or inforcer.
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MONITORING FOR TRACE METALS IN THE
ATMOSPHERIC ENVIRONMENT: PROBLEMS AND NEEDS
P. R. HARRISON
Department of Environmental Control
Chicago, Illinois
It is difficult to write a paper of readable length on
such a broad topic. It takes arrogance or naivety to even
attempt it. However, not to do one's best shows a
contentment with ignorance. Not being so contented,
the author wishes to plead only humility, leaving the
reader to choose the motive.
In order to properly scale the task we should consider
the magnitude (or better stated, the lack of magnitude)
of the subject in mind. If we wish to end up with a
reasonable approximation of the concentration of a
trace element floating in the free atmosphere, we must
first realize that a sampler is a concentrative process. For
example, the high volume sampler will draw
approximately 1.5 to 2 cubic meters of air through the
filter each minute. Usually these will run for 24 hours,
representing somewhere between 2200 and 2900 cubic
meters of air concentrated on a piece of paper 63 square
inches in surface, each inch representing about 40 cubic
meters of air. We then take that filter paper, remove the
material by extractions, and then institue a subsequent
chemical concentrative process. We thus go through two
concentrative and one removal process with all the
biases, errors, and selectivities involved. Considering all
possible points of error, it seems a miracle that we get
meaningful results at all. In many unfortuante cases we
probably fooled ourselves into thinking so.
We make this example in order to show that indeed
there are difficult, but not unique, problems in obtaining
elemental analysis in the atmospheric environment. The
scope of this paper will be to point out a general
procedure, considerations involved, and suggest some
needs and solutions to those needs. Since there are as
many details in the analytical procedures as there are
chemists, we will simply give an outline of a workable
procedure with details and examples.
Suggested Procedures in Reaching a Believable Number
The first task that we must do is the obvious literature
search. This is an imperative task but should be done
with a jaundice eye. There are some base documents
which could be suggested at this time. Probably one of
the most complete documents of elemental analysis of
particulate in the air is a thesis (1) which lists several
values of more than 30 elements obtained from both
urban sources and the northwest Indiana area (2), as well
as data from more remote areas across southern Canada.
There are other general documents such as the air
quality data from the National Air Sampling Network
(NASN) prepared by the Federal Environmental
Protection Agency (EPA). The latest completed
document is for 1968 values (APTD-0978,1968). Other
more recent information is available through
professional society publications. The problem with
these documents is that they represent only one site,
usually located in the center of an urban area. Exposures
of these sites are not all representative of these areas.
For example, in Chicago the station is located
approximately 15 feet back from one of the most
heavily traveled streets and is 12 feet above the ground.
Add the fact that it is within 5 feet of a seven-story
building, in an area surrounded by even taller buildings,
and it is no wonder that this station shows high
particulate levels as well as high concentrations of trace
metals. This accounts for a tendency toward larger size
distributions than other stations which are not located in
dust traps.
We can usually find documents on a particular
element. Lead, copper, and cadmium have been
described in an urban area for six separate days over a
network of 50 stations throughout the Chicago and
northwest Indiana regions (2). Please see Table 1.
Many older documents cite numbers which can be
used as guidelines. For example, prior to 1960 there
were over 3,000 references to lead alone. Of course, the
more rare the element, the more rare the references in
most cases.
Having perused the literature and estimated the size of
the needle, we must now choose a method of capture
123
-------
124
CYCLING AND CONTROL OF METALS
and a method of analysis. In both cases we should
concern ourselves with sensitivity. If it is known or
suspected that the particle size distribution is such that
the particles are less than 1 micron on the average, we
should consider more positive, smaller pored filter
papers. Good references are obtained from companies
making filter papers such as Gelman Instruments, Ann
Arbor, Michigan and Millipore Corporation, Rosemont,
Illinois. If the average size of the particle is unknown or
it is larger in the mean than 1 micron, a standard,
inexpensive high volume filter is probably as good as any
device in capturing a larger amount of material over a
reasonable period of time.
Now comes the problem. If we want a large amount of
sample we use the whole filter, which then could draw
high contamination or blank value from the paper. On
the other hand, we can choose a smaller part of the filter
paper, decreasing our blank substantially, but also
decreasing our sample. A convenient method of
optimizing this problem is to calculate a signal, i.e.,
concentration, to blank ratio which automatically
dictates that before any sampling is analyzed a thorough
investigation, concerning the contamination of the filter
media be made. Tables 2 through 8 are examples of the
kind of thoroughness required for selection of the filter
for impaction media for subsequent analysis by neutron
activation (3).
Assuming that we have acceptable blank levels, we
must decide how much material to capture in order to
obtain a meaningful sample. The amount will be dictated
by the method of analysis. Now we see that we have to
make two decisions in fairly rigid tandem. We either
choose the time period of investigation and obtain a
method capable of the necessary sensitivity, or we
choose a method and alter our sampling time or amount
necessary for capture accordingly. In most cases, this is a
moot point because the equipment is already purchased
before the counter decision has been made.
Unfortunately, too many times, the net result is that the
micro-structure desired is elusive due to the lack of
TABLE 1 CONCENTRATIONS AT MAXIMUM, MINIMUM, AND CONTROL STATION
Element
S
Fe
Ca
Cu
Al
Mg
K
Zn
Na
Mn
Br
Ti
Cr
Sb
V
Ce
As
La
W
Ag
Hg
Se
Ga
Sc
Co
Th
Sm
Eu
In
Maximum
18,000 (10,000)*
13,000 (3,000)
7,000 (700)
4,000 (200)
3,100 (300)
2,700 (1,000)
1,860 (110)
1,550 (200)
500 (50)
390 (50)
300 (30)
280 (50)
113 (20)
31 (3)
18.1 (1.5)
13 (1.5)
12 (2)
5.9 (0.4)
5.6 (1)
5 (2)
4.9 (0.9)
4.4 (1.2)
3.5 (1.0)
3.1 (0.3)
2.6 (0.6)
1.3 (0.4)
0.65 (0.20)
0.17(0.03)
0.15 (0.06)
Concentrations ng/m3
Minimum
3,000 (3,000)
1,420 (120)
1,410 (200)
25 (4)
1 ,375 (70)
530 (300)
730 (90)
100 (12)
160 (20)
63 (3)
26 (2)
120 (25)
6.2 (0.8)
2.2 (0.2)
4.01 (1.0)
1.4 (0.1)
2 (1)
0.9 (0.3)
0.3 (0.3)
0.5
0.8 (0.3)
0.8 (0.5)
0.25(0.15)
0.92(0.1)
0.47 (0.06)
0.17(0.02)
0.17(0.02)
0.06(0.01)
0.03 (0.03)
Concentration Ratios
Niles
11,000 (5,000)
1,900 (100)
1 ,000 (200)
280 (20)
1 ,200 (70)
500 (300)
720 (50)
160 (20)
170 (20)
62 (3)
38 (6)
120 (25)
9.5 (0.8)
6.0 (0.3)
5.0 (0.3)
0.82 (0.06)
4.6 (2)
1.3 (0.3)
0.4 (0.2)
1
1 .8 (0.3)
2.5 (0.5)
0.9 (0.4)
1.2 (0.1)
0.95 (0.1)
0.27 (0.08)
0.24 (0.03)
0.055 (0.02)
0.04 (0.03)
Max/Min
6 (9)
9.7 (3)
5.0(0.7)
160 (30)
2.3 (0.3)
5.1 (3)
2.5 (0.4)
16 (2)
3.1 (0.4)
6.2(1)
12 (1.5)
2.3 (0.7)
18 (3)
14 (2)
4.5(1.2)
9.3(1)
5 (4)
6.6(2.5)
19 (19)
10
6.1 (3)
5.5(3)
14 (10)
3.4(0.4)
5.5(1)
7.6(2)
3.8(1.5)
2.8(0.5)
5 (5)
Max/Niles
1.6(1.0)
7.2 (2.0)
7.0(1.5)
14 (1.5)
2.6(0.3)
5.4(3)
2.4(0.3)
9.6(1.4)
2.9 (0.4)
6.3(1.0)
8.1 (2)
2.3 (0.7)
12 (2)
5.3(0.7)
3.6(0.4)
16 (4)
2.6(1.2)
4.5(1.0)
14 (7)
5
2.6(0.7)
1.5(0.6)
3.9(1.2)
2.6(0.3)
2.7 (0.7)
(1.0)
2.0(0.4)
3.0(0.5)
3.7 (3)
(After K. Rahn 1971)
•Large filter
impurity correction.
-------
MONITORING - AIR
125
sensitivity and specificity of the analytical technique and
instrumentation.
Following the same argument, we usually try to
increase the effective sensitivity of our instrumentation
by separating the participate material from our capturing
media or by extracting the interesting part. We then
must concern ourselves with the efficiencies of
extraction and the possible interference due to elements
of similar chemical nature. At this point the arguments
take place among the chemists, and I desist from
pursuing this particular subject any further except to say
that the task must be to increase the sensitivity of the
instrumentation and to eliminate those separations and
subsequent concentration techniques which require very
pure reagents and the precision of a dedicated
watchmaker.
Assuming the above considerations are well under
control, we must now estimate the number and locations
of the samples needed for proper description of the
phenomena of interest. Once the number of samples has
been estimated, treble it, for experience so dictates. This
will cause us to calculate the time it will take to analyze
all our samples (which usually forces the researcher back
to the drawing board to narrow the scope of study
and/or to select a new method of analysis). In some
cases, time advantage can be found through parallel
analysis rather than serial, one at a time, methods. For
example, if equipment is available we can batch the
preparations and chemical procedures. Anodic stripping
voltametry (ASV) has an advantage, inasmuch as it is a
timed analysis which allows multiple platings sequenced
a minute or two apart. The samples are analyzed and
changed before the next sampling sequence is ready for
stripping (2).
Throughout this whole procedure we must carry along
blanks of the capturing media precisely the way we
would handle the media and sample itself. For example,
filter papers from the same box should be carried to the
site, put on the sampler, and removed without a sample
being taken. These samples should be analyzed as if they
were real. We can detect and correct for system blanks in
this manner if they so occur. This is a primary control
method for the media. Of course, good chemical
standards should also be prepared and carefully checked.
We will pause here, after describing many of the above
problems, to clearly state the needs to this point. They
are as follows:
1. A more positive capturing technique.
2. The capturing media must be relatively clean,
homogeneous, and have a listed assay as required by
any chemical reagent.
3. We must eliminate many of the extraction, separation,
and chemical concentrative steps by increasing the
sensitivity of the physical measuring devices.
Having forged onward to the obtaining of several
numbers, and having full confidence in those numbers
and their error limits, we will now hypothesize that we
have efficiently captured the material in question, have
analyzed that material for the element(s) so desired,
subtracted the blanks, eliminated its systematic errors,
and have a reasonable understanding of the
concentrations. We now proceed to the next step.
Data Representation and Interpretation
Two primary areas to consider in interpretation of
your hard-won data are the manner of presentation and
pertinent auxiliary information. These considerations
probably take as large a share of failures as do the
problems with analytical techniques.
This first point is axiomatic. We should not involve
ourselves in securing or interpreting atmospheric samples
of air quality without the advice and consultation of a
reasonably qualified applied meteorologist. With even
brief consultation periods, we can eliminate many
potentially fatal mistakes. A case in point is that of a
renowned researcher who carefully correlated excess
deaths of infants and aged persons downwind of a
nuclear power plant. His evidence and conclusions
showed that there were approximately 10 percent excess
deaths in an area away from the prevailing wind. After
presenting his evidence at more than one meeting, as
well as causing civilian alarm by newspaper releases, a
meteorologist pointed out that the barbs on the wind
direction lines are customarily put on the end of the line
pointing in the direction from which the wind is
blowing. Thus this nonmeteorologist statistician had
proven that nuclear radiation from this particular facility
was good for children and the aged. This example
illustrates one of the obvious needs for a meteorologist
to assist in the design and interpretation of the data.
Associated data could take the form of the total
suspended particulate weights to indicate the percentage
of total sample with respect to the elements in question.
Wind parameters, direction, and speed are needed to
estimate the transport characteristics so we can
subsequently identify the source region. Finally, an
estimation of the source inventory is desired in order to
validate our source strength predictions or to suggest
new hitherto unknown sources. These inventories should
take the form of both point source and area-wide source
estimations. Examples of this technique are presented in
Figures 1 to 8, representing an area-wide distribution of
suspended particulate, its lead fraction, selected wind
roses, and an estimation of the urban traffic densities.
The weakest point in this presentation, as often is the
case, is the emission inventory. Copper and cadmium are
presented for the same day but without emission
inventory data. Another set of data are shown in
Figures 9 to 12 (2). Depicted here is the dependence of
lead levels on wind direction adjacent to a large metro-
politan area. It should be noted that the maximum
occur shortly after the wind direction comes from the
sector containing the large city. The minimum occur
outside that sector. It will also be noted that the lead
-------
126
CYCLING AND CONTROL OF METALS
levels reached a detectable minimum while the copper
and cadmium levels continued to drop below detectable
limits, representing a background value for lead. We
present this data in order to show that proper
interpretation and presentation of associate information
leads to much greater wealth of knowledge than simple
presentation of the data by itself.
In summary, we should have sufficient information to
properly understand the emission strengths and
transport characteristics of our contaminants, as well as
the amount of receptor exposure (concentration).
We have shown two methods of data representation
which inherently contain compilation and correlation
difficulties. The first is that of isopleth analysis where,
for example, concentration values may be too large to
conveniently plot and/or where isopleth gradients are
too steep to draw a distinguishable line. When comparing
air quality data directly to meteorological data, a second
difficulty, that of correlation, is made evident. To a
statistician it is obvious that if time was held constant,
correlations between trace metal concentrations and
wind speed, wind direction, humidity, and etc. would
probably lead to poor or superfluous conclusions.
Plotting the information adjacent to each other, we
realize a time delay in the advection of the material from
the source region to the sensor. The conclusions are thus
convincing without being lost in the statistical
formulations. Please see Figure 10.
We cannot represent such area-wide data in straight
concentration isopleths, but in percentages of the
maximum. Figures 13 and 14 represent the usefulness of
such techniques. In this presentation we plot logarithmic
percentages of concentrations from 50, 25, 12, 6
percent, and so on. The advantage is that we have a
graphical means of interpreting source regions (or lack
thereof) in a relatively uncluttered manner while still
maintaining sufficient detail. Point sources become
obvious due to the reasonable clustering of the isopleths.
If there are no local sources we can draw few lines of
constant percent due to the lack of variation in
concentrations. These two graphs indicate separate wind
directions which easily indicate a source region west and
between Stations "J" and "G"
If a large number of days or periods of samples can be
obtained, pollution roses such as shown in Figure 15 are
very helpful. Nonvariation in the concentration of a
pollution rose indicates that either the material is fairly
universal throughout a large region and is background in
origin, or that the material is emitted uniformly
throughout the region (e.g. lead).
A final point should be made. In circumlocution, it is
important to carefully select and properly describe the
location of the sampling points. Again, a reasonably
competent applied meteorologist can be of invaluable
assistance. At the onset of this article the location of a
certain continuous air monitoring project station
(CAMP) was discussed. The advisability of such a
location is not to be criticized if we fully understand and
desire to measure that particular situation. We can
severely criticize anyone who extends his interpretation
of data gained from such a biased location to the total
region. In other words, we should use multiple sampling
points to describe a region's exposure to any
contaminant. Single point source sampling should be
used only when the location is properly described in
sufficient detail for the reader who may use such data to
know precisely the limitations of such data. Thus, we
need a careful selection of sampler sites.
CONCLUSIONS
Our conclusions will be quite brief and simple. After
discussing the above considerations pertaining to site
locations, analytical techniques, interpretations, and
methods of presentation, it becomes quite apparent that
if we are to succeed in the business of advancing the
knowledge of elemental concentration distribution in
the atmospheric environment we must rely upon the
experience and expertise of several disciplines. We must
conclude that any meaningful experiment will be well
thought out and discussed in detail with persons of
many disciplines in conjunction with the researchers.
Our purpose is to convince one that this approach is
mandatory.
If one is to not sentence his hard earned numbers to
the archives of perfunctory literature, we would suggest
that a multi-discipline team approach be chosen. It is
quite evident that our utmost and immediate problem is
to meet the obvious needs.
-------
TABLE 2 FILTER MATERIAL INVESTIGATED
Filter Material
Polystyrene
Polystyrene
Cellulose-
organic binder
Cellulose
Membrane
cellulose esters
Membrane
cellulose esters
Membrane
cellulose esters
Membrane
cellulose esters
Membrane
cellulose acetate
Membrane
cellulose triacetate
Manufacturer's Name
Microsorban
Microsorban
Whatman No. 41
—
MF-Millipore
MF-Millipore
MF-Millipore
MF-Millipore
Cellotate
Metricel
(Key)
(PS)
(DMS)
(W41)
(C)
(HAWP025)
(HAWP047)
(AAWP025)
(AAWP047)
(EHWP047)
(GA-6)
Manufacturer
Delbag Luftfilter
(Germany)
Delbag Luftfilter
(Germany)
W. and R. Balston
Ltd. (England)
C. H. Dexter and Sons
(USA)
Millipore Filter
Corp. (USA)
Millipore Filter
Corp. (USA)
Millipore Filter
Corp. (USA)
Millipore Filter
Corp. (USA)
Millipore Filter
Corp. (USA)
Gelman Instrument
Co. (USA)
Specifications
-
—
—
—
Pore size 0.45 um,
diameter 25 mm
Pore size 0.45 um,
diameter 47 mm
Pore size 0.8 um,
diameter 25 mm
Pore size 0.8 um,
diameter 47mm
Pore size 0.5 um,
diameter 47mm
Pore size 0.45 um,
diameter 47mm
Comments
No longer
available
Presently
available
Tightly
woven
Loosely
woven
—
—
—
—
—
—
(After K. Rahn 1971)
O
•z,
-------
Cl
Br
S
Na
K
Mg
Ca
Ba
A]
Sc
Ce
La
Ti
Fe
Mn
Co
Ni
Ag
Cu
Zn
Sb
Cr
Hg
V
PS
3,000
25
80
20
< 200
300
7,000
20
0.04
<0.4
<0.2
10
100
1
0.2
25
<2
10
60
2.5
5
3
0.06
DMS
27,000
1,000
±30,000
90
8
< 1 ,500
300
<500
20
<0.01
< 1
<0.1
70
85
2
0.2
<25
< 2
320
515
1
2
1
< 0.6
W41
100
5
150
15
<80
140
< 100
12
<0.05
<0.5
<0.2
10
40
0.5
0.1
<10
2
<4
<25
0.15
3
0.5
<0.03
TABLE 3
C
300
20
6,000
700
200
2,400
3,800
< 100
200
0.2
<0.3
<0.3
50
300
80
0.8
60
3
90
30
0.5
12
3
0.5
FILTER IMPURITY LEVELS (ng/cm2)
HAWP025
1,000
4
600
130
<300
670
<100
20
<0.05
<0.5
<0.1
15
40
7
0.2
<8
<4
20
25
0.5
15
<0.4
<0.06
HAWP047
1,000
3
330
100
<200
250
< 100
10
<0.01
< 1
<0.2
5
<300
2
< 1
<50
-
40
20
3
14
< 1
0.09
AAWP025
1,700
< 5
4,800
520
120
400
500
<100
15
<0.01
<0.5
<0.5
10
80
2.5
0.4
14
< 3
85
10
0.4
20
< 1
<0.2
AAWP047 EHWP047 GA-6
1 ,000 1 ,800 600
< 2 6 4
400 1,800 2,200
100
200
370 570 1,250
<100
10 60 740
< 0.05
< 0.3
< 0.2
< 10
40
262
0.1
< 20
< 1
60 25 30
7
1
15
0.5
<0.05 < 0.05 <0.05
CYCLING
X
O
n
0
70
0
o
hn
tn
H
£
(~) not determined.
(After K. Rahn 1971)
-------
TABLE 4 SELECTED PHYSICAL PROPERTIES OF FILTERS
Filter material
Flow rate (1-minr '-cm"2)
20 x 25 cm
(effective surface 400 cm2 )
Flow rate (l-minr'-crrT2)
47 mm diameter
(effective surface 9.62 cm2)
Flow rate (1 -min ." l - cm" )
25 mm diameter
(effective surface 3.68 cm2)
Retention (%) of 0.3 ^m
D. 0. P. aerosol*
(25 mm diameter)
Retention (%) of 0.3 Mm
D. O. P. aerosol *
(20 x 25 cm)
Volume filtered
at 1 0% reduction in flow *
(m3 air/cm2 filter)
Thickness (mm) t
Tensile strength (kg- cm" 1 ) £
PS
4.5
6.5
12
99.96
99.8
48
0.15
DMS
4.5
6.5
13
99.95
99.7
35
0.15
W41 C
4.5 6
6.5 7
13 17
99.7
91 80f
2.0 >50*
2.8*
0.25
1.41
HAWP025 HAWP047 AAWP025 AAWP047 EHWP047 GA-6
2.6 - 4.8 2.6 2.6
4.3 7.3 - -
>99.98 - 99.97 - -
4.1* 4.1* 6.3 6.3
0.29 0.29
'Determined by the authors in Ann Arbor, Michigan
t Determined by Brar et al. (1970) for total participate by weight in Chicago
^Determined by Lockhart and Patterson (Lockhart, L. B., and R. L. Patterson, In: RL Report 6054,
U. S. Naval Research Laboratory, Washington, D. C., 1964.
(After K. Rahn 1971)
S
O
2
H
O
?o
1
I
-------
130 CYCLING AND CONTROL OF METALS
TABLE 5 SAMPLE/BLANK RATIOS FOR 25 mm DIAMETER W41
FILTERS, USING NILES, MICHIGAN CONCENTRATIONS
(Sample/Blank)
Element
Cl
Br
Na
K
Ca
Al
Ti
Fe
Mn
Co
Sb
Cr
V
Cu
Zn
•For \l\
Cone.
100
70
200
400
900
800
100
600
30
0
2
10
3
30
60
mmdiame
(ng/m3) 1 hr sample
t 0.6t
8
0.8
16
4
40
6
9
35
.3 1-8
8
2
>60
> 4
> 1.4
;ter multiply by 2'|7
4 hr sample
2.3t
33
3
62
15
160
23
35
140
7.0
31
8
>230
> 17
> 5.6
*
24 hr sample
12t
160
16
310
75
800
120
180
700
35
160
40
> 1200
> 80
> 28
"("From cascade impactor data of same period.
(After K. Rahn 1971)
TABLE 6 SAMPLING TIMES TO EQUAL BLANK VALUES OR DETECTION LIMITS
Sampling time at Niles in hours on 25 mm filter disc to equal:
Element
Cl
Br
Na
K
Mg
Ca
Al
Ti
Fe
Mn
Co
Cu
Zn
Sb
Cr
Detection
Limit
2
0.15
0.5
0.1
1.5
0.5
0.02
0.6
1
0.05
2.8
2
0.7
2
0.8
PS
Blank
60
0.8
1
0.1
—
0.7
0.05
0.2
0.3
0.08
1.5
1
2.5
3.5
1
DMS
Blank
500
29
0.9
0.04
—
0.6
0.04
1
0.25
0.15
1
25
18
1.5
0.35
W41
Blank
1.7
0.15
1.5
0.085
—
0.25
0.025
0.1
0.1
0.035
0.6
_
—
0.2
0.5
C
Blank
4
0.4
5
0.8
4
5.5
0.3
0.5
0.6
4
3.3
5
0.75
0.5
1.5
HAWP025
Blank
50
0.35
18
2.2
—
3.8
0.15
0.7
0.35
1.5
3.5
5
2.5
2
7.8
AAWPO25
Blank
50
—
9
1
1.5
1.7
0.06
0.35
0.4
0.3
4
12
0.6
1
6
( ) If for the blank value only a higher limit was found or if it was not determined.
(After K. Rahn 1971)
-------
MONITORING - AIR 131
TABLE 7 POLYSTYRENE-CELLULOSE EFFICIENCY COMPARISON
Element
Cl
Br
S
Na
K
Mg
Ca
Al
Ga
Sc
Ce
La
Sm
Eu
Ti
Fe
Mn
Co
Ni
W
Ag
Cu
Zn
As
Sb
Atmospheric concentration (ng/m3)
Polystyrene
4400 (500)*
350 (90)
15 (15)
900 (150)
4000 (400)
730 (400)
4100 (800)
2300 (400)
4.5 (1.0)
4.9 (0.6)
17 (3)
4.6 (0.5)
0.67 (0.10)
0.18 (0.04)
170 (50)
22,000 (4,000)
240 (40)
3.9 (0.5)
55 (55)
1.5 (0.7)
3 (3)
130 (20)
4400 (200)
29 (7)
21 (5)
Whatman no. 41
7500
500
43
1300
4200
760
3900
2800
4.6
3.4
12
4.6
0.67
0.13
280
15,000
280
2.9
70
<2
2.5
160
4300
35
21
(500)
(50)
(25)
(200)
(200)
(150)
(500)
(200)
(1.5)
(0.5)
(2)
(0.5)
(0.10)
(0.03)
(0.03)
(3,000)
(30)
(0.4)
(60)
(2.0)
(20)
(200)
(8)
(5)
Concentration ratio
What. no. 41 / poly.
1.70
1.43
2.87
1.44
1.05
1.04
0.95
1.22
1.02
0.69
0.71
1.00
1.00
0.72
1.65
0.68
1.12
0.74
1.27
-
0.83
1.23
0.98
1.21
1.00
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132 CYCLING AND CONTROL OF METALS
TABLES IMPURITY LEVELS IN
DURETHENE POLETHYLENE,
NO. 12010
Element
Cl
Br
Na
K
Mg
Al
Sc
Ce
La
Ti
Fe
Mn
Co
Ni
Ag
Cu
Zn
Sb
Cr
Hg
Concentration (ng- cm 2)
8 (2)
1.0 (0.5)
2.5 (0.4)
1.2 (0.3)
8 (6)
6.8 (1.0)
< 0.006
< 0.009
< 0.04
11 (6)
<11
0.10 (0.02)
0.02 (0.01)
< 1.3
< 0.3
1.0 (0.5)
2 (1)
0.04 (0.01)
< 0.3
< 0.1
-------
MONITORING - AIR 133
MICHIGAN CITY
ILLINOIS
INDIANA
Figure 1. Estimation of heavy traffic densities.
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134
CYCLING AND CONTROL OF METALS
THURS. 20 JUNE, 1968
ILLINOIS
INDIANA
Figure 2. Wind direction. Arrows point in the direction that the wind is
blowing. The number depicts the number of hours of that
direction. C represents number of hours calm (3 miles per hour
or less). This convention is opposite to classical methods used
by meteorologists.
-------
MONITORING - AIR 135
THURS 20 JUNE 1968
SUSPENDED PARTICULATE >ug-m-3
LAKE MICHIGAN
CHICAGO 250,/V) \«
ILLINOIS
INDIANA
MICHIGAN CITY
Figure 3. Isopleths of suspended particulate. Data obtained from 24-hour,
high-volume samplers. Original data shown on Figure 4.
-------
136 CYCLING AND CONTROL OF METALS
THURS 20 JUNE 1968
CHICAGO
SUSPENDED PARTICULATE Mg-m
ILLINOIS
INDIANA
81
Figure 4. Suspended particulate values from individual stations.
-------
MONITORING - AIR
137
THURS. 20 JUNE, 1968
CHICAGO
ILLINOIS
Figure 5. Isopleths of lead fraction from 24-hour high-volume samples.
-------
138
CYCLING AND CONTROL OF METALS
THURS. 20 JUNE, 1968
CHICAGO
ILLINOIS
15
INDIANA
.5
Figure 6. Lead fraction of suspended particulate irom individual stations.
-------
MONITORING - AIR 139
THURS. 20 JUNE 1968
CHICAGO
ILLINOIS
Figure 1. Isopleths of copper fraction from 24-hour high-volume samples.
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140 CYCLING AND CONTROL OF METALS
THURS 20 JUNE 1968
C u , n g— m
LAKE MICHIGAN
CHICAGO
• 10
29
49
ILLINO IS
INDIANA
18
Figure 8. Copper fraction of suspended particulate from individual stations.
ANN ARBOR
MICHIGAN
Figure 9. Location of Ann Arbor in relation to Metropolitan Detroit.
-------
MONITORING - AIR
141
u
o
26.7
21.1
15.6
10.0
-4.4
-1.1
-6.7
I I I I I
80
70
60
50
40
30
I I I 20
I
ei
22 02 06 10 14 18 22 02 06 10 14
SAMPLE TIME, EST, 26-28 APRIL 1968
WIND DIRECTION
CO — '
O> s(J «>
o o o
00°
270°
I 1 l I I
-
1
5
111 III
m/s
. DETROIT
1 SECTOR |
h
-h
i i i 1 I
H^
~*~
=H,_H
1 1 1
^^^
1 1
^•^M
•
••^H
-
^M
;
-
1 1 1 1 1
- s
22 02 06 10 14 18 22 02 06
SAMPLE TIME, EST, 26-28 APRIL 1968
Figure 10. Meterological parameters plotted versus time in 2-hour averages.
Width of vertical line for wind direction represents the arithmetic
variation in wind direction. The length of the horizontal line
represents the average wind speed in meters per second.
- E
- N
- W
10 14
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142
CYCLING AND CONTROL OF METALS
3000
1000
300
100
300
100
30
10
Pb BLANK
D Q Cu BLANK
Cd BLANK
Pb o
Cu n
Cd A
1000
22 02 06 10 14 18 22 02 06 10 14
SAMPLE TIME EST 26-28 APRIL 1968
Figure 11. Concentration of lead, copper, and cadmium
versus 2-hour time periods. Blank levels
represent maximum values of any blank run.
f E D
PARTICLE SIZE-
Figure 12. Composite size distribution of the 21 sample
runs (2-hour periods). H stage represents a
back-up filter to a seven-stage Andersen sampler,
mediandiameter 0.5 microns.
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MONITORING - AIR
143
6% ,
12%
TRACE METAL
CONCENTRATION
lioplethi in percent of
12%
12%
Percentage Compositior
of Particulate
110piettii in percent of
Maximum Concent ratio r
Figure 13. Distribution of zinc, April 11 and June 29, 1971. Figure 14. Distribution of zinc, March 7 and 23, 1971.
SO2 7-71 STATION 1
N MAX 0-10
S02 7-71 STATION 2
N MAX 0-28
S02 7-71 STATION 3
N MAX 0-09
SO2 7-71 STATION 4
N MAX 0-37
Figure 15. Selected wind roses for July 1971 from City of
Chicago Telemetered Air Monitoring Network
(TAMN). (Courtesy of Dr. M. J. Weins, University
of Illinois Materials Engineering, Chicago).
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144
CYCLING AND CONTROL OF METALS
REFERENCES
1. Rahn, K. A., Sources of Trace Elements in Aerosols —
An Approach to Clean Air, Ph. D. Thesis, The Univ.
of Michigan, Ann Arbor, Michigan, 1971.
2. Harrison, P. R., Area-wide Distribution of Lead,
Copper, Cadmium and Bismuth in Atmospheric
Particulates in Chicago and Northwest Indiana: A
Multi-sample Application and Anodic Stripping
Voltammetry, Ph. D. Thesis, The Univ. of
Michigan, 1970.
3. Dams, R., K. A. Rahn, and J. W. Winchester,
Evaluation of Filter Materials and Impaction
Surfaces for Nondestructive Neutron Activation
Analysis of Aerosols, Env. Sci. Tech., 1971
(submitted).
BIBLIOGRAPHY
1. Brar, S. S., D. M. Nelson, J. R. Kline, P. F. Gustafson,
E. L. Kanabrocki, C. E. Moore, and D. M. Hattori,
Instrumental Analysis for Trace Elements Present
in Chicago Area Surface Air, J. Geophys. Res., 75
(15), 2939,1970.
2. Dams, R., J. A. Robbins, K. A. Rahn, and J. W.
Winchester, Nondestructive Neutron Activation
Analysis of Air Pollution Particulates, Anal. Chem.,
42,861,1970.
3. Harrison, P. R., W. R. Matson, and J. W. Winchester,
Time Variations of Lead, Copper and Cadmium
Concentrations in Aerosols in Ann Arbor,
Michigan, Atmospheric Environment 5, 613,1971.
4. Harrison, P. R., K. A. Rahn, R. Dams, J. A. Robbins,
J. W. Winchester, S. S. Briar, and D. M. Nelson,
Areawide Trace Metal Concentrations Measured by
Multielement Neutron Activation Analysis, A One
Day Study in Northwest Indiana, APCA 21:9,
September 1971.
5. Rahn, K. A., R. Dams, J. A. Robbins, and J. W.
Winchester, Diurnal Variations of Aerosol Trace
Element Concentrations as Determined by
Nondestructive Neutron Activation Analysis, Atm.
Env., 1971 (in press).
-------
MONITORING FOR TRACE METALS
WATER ENVIRONMENT
D. G. BALLINGER
National Environmental Research Center
Cincinnati, Ohio
MONITORING
Monitoring for metals in the aquatic environment may
be described as (a) the location of significant sources of
metals discharged to surface waters, the characterization
of these discharges as to specific metals, their
concentration and physical state, (b) the immediate
impact of these discharges on receiving water quality,
and (c) the broad evaluation of the concentration of
metals in the aquatic environment, including natural
background and measurable changes due to human
activity.
These types of monitoring may be classified as:
1. Source Monitoring — resulting from the mining,
refining, and manufacturing use of metals.
2. Near-Source Monitoring — in the immediate vicinity
of the discharge, to determine localized effects.
3. Ambient Monitoring — baseline data collection to
assess long-term changes and general levels of metals.
SOURCE MONITORING
Responsibility for monitoring metals at the source is
divided between the industry which creates the discharge
and the regulating agencies, both state and federal,
charged with maintaining satisfactory water quality. The
provision of the 1899 Refuse Act requires the permit
applicant to identify the metals present in his waste and
to report the maximum concentrations present at any
time (1). The Standard Industrial Classification
categories reporting are listed in Table 1.
Implementation of the new amendments to the
Federal Water Pollution Control Act will similarly
require monitoring data on metals in industrial effluents.
Routine examination of effluents will be needed to
evaluate the efficiency of treatment and control
measures.
State regulatory agencies, in cooperation with EPA,
are conducting source sampling to determine compliance
with permit applications. These monitoring activities will
be expanded under the new effluent guidelines and
TABLE 1 HEAVY METAL REPORTING
REQUIREMENTS
SIC
classification
Industry
10-14 Mining
22 Textile Mill Products
2491 Wood Preserving
26 Paper and Allied Products
281 Industrial Inorganic and Organic Chemicals
2818 Industrial Organic Chemicals
2819 Nuclear Fuel Reprocessing
283 Drugs
2879 Agricultural Chemicals
2892 Explosives
29 Petroleum Refining
33 Primary Metal Industries
332 Iron and Steel Foundries
333 Primary Smelting and Refining
336 Nonferrous Foundries
34 Fabricated Metal Products
347 Coating, Engraving
36 Electrical Machinery
3731 Ship Building and Repairing
285 Paints, Varnishes, Lacquers, and Enamels
standards. Where violations occur, EPA is involved in
case preparation, i.e., gathering source data in support of
180-day notices or other legal actions.
NEAR-SOURCE MONITORING
Collection of metals data in receiving waters
establishes the immediate impact of the discharge. At
these downstream points concentrations are maximum,
since dilution and precipitation at greater distances will
reduce the levels significantly. Toxicity effects may be
145
-------
146
CYCLING AND CONTROL OF METALS
acute in the mixing zone, and transport processes begin
in these areas. Evaluation of metals concentrations near
the source contributes to the separation of acute from
long-term chronic effects. These data are necessary to
establish the responsibility for unsatisfactory water
quality and to determine requirements for abatement
from known sources of contaminants.
The discharge of wastes containing heavy metals often
results in the formation of insoluble materials, as the
result of reaction with alkaline waters, coprecipitation,
or adsorption on clay particles. The familiar yellow boy
in streams receiving acid mine drainage is an example of
these chemical reactions. In many locations immediately
downstream from metals discharges, bottom sediments
contain large amounts of metals and may be classified as
industrial sludges. Sampling and analysis of the
deposited materials give important information on the
original source of the metals and are essential to proper
evaluation of the impact on the receiving water. These
reservoirs of metals may contribute to poor water
quality long after the discharge has been eliminated.
Monitoring in the vicinity of waste discharges is
primarily the responsibility of the regulating authorities
although many industries conduct their own programs to
assess impact. The states and EPA carry out surveys and
operate long-term stations at points of maximum
damage.
AMBIENT MONITORING
Collection of base-line water quality data, or trend
monitoring as it is often called, is essential to an
understanding of general water quality available for all
purposes and for the assessment of degradation or
improvement in specific waterway systems. Public
agencies, both state and federal, have been conducting
such monitoring programs for many years. In 1968 the
Federal Water Pollution Control Administration
published a summary of trace metals data on samples
collected from October 1962 through September 1967
at approximately 130 stations throughout the
contiguous United States (2). These data, derived from
more than 30,000 separate determinations, indicate that,
of the nineteen elements routinely sought, boron,
barium, and strontium occurred with a frequency of
over 98 percent, while aluminum, lead, chromium,
molybdenum, and nickel varied between 16 and 33
percent. Cadmium, beryllium, silver, cobalt, vanadium,
and arsenic were detected in less than 7 percent of the
samples.
It should be emphasized that these data represent only
the metals in solution and that total concentrations of
metals, including suspended forms, would be much
higher. Concentrations given, therefore, represent only
the minimum levels present and, while permissible
concentrations established by the USPHS Drinking
Water Standards for public water supplies were exceeded
in only isolated samples, the levels considered safe for
aquatic life were probably exceeded in many locations.
The U. S. Geological Survey has published a survey of
more than 720 stations sampled in October and
November 1970 (3). The samples were analyzed for
arsenic, cadmium, hexavalent chromium, cobalt, lead,
mercury, and zinc. As in the FWPCA study, only soluble
metals were determined. Twenty-one percent of the
samples has arsenic greater than 10 /ug/1, 4 percent of
the cadmium results exceeded 10 /ig/1 (the PHS upper
limit for drinking water). There were no hexavalent
chromium concentrations in excess of 50 /zg/1, and few
samples contained more than 50 jLtg/1 of lead. In none of
the samples did the concentration of dissolved mercury
exceed 5 /ig/1, while a significant number of samples
exceeded the drinking water standard of 5000 jug/1 of
zinc.
A survey of public drinking water systems conducted
by the Public Health Service in 1969 (4) has indicated
that 1.6 percent of the supplies exceeded the limit for
copper, 8.6 percent exceeded the limit for iron, 8.1
percent exceeded the limit for manganese, and 1.4
percent exceeded the mandatory limit for lead, while
standards for the other metals were exceeded by less
than 1 percent of the water supplies examined.
Considering that only 969 water supplies were tested,
some concern for the quality of water reaching the
consumer is merited.
All of the above studies show a problem of metals in
the aquatic environment, but the problem may be more
acute than realized since limitations of sampling and
analysis may hide significant factors of toxicity.
DATA STORAGE AND RETRIEVAL
Water monitoring data collected by federal and some
state agencies is stored in a dedicated computer system
operated by EPA. A large amount of information on
metals concentrations in surface waters is available from
this data bank, which can be accessed by any of the ten
regional EPA offices.
MONITORING REQUIREMENTS
A satisfactory monitoring program for metals in the
aquatic environment has certain basic requirements.
These are proper sampling frequency, control of sample
stability, specificity, adequate sensitivity, high degree of
accuracy, and satisfactory analytical precision.
Certain industrial operations producing discharge of
metals are batch operations, resulting in wide variations
in loading and concentration. Depending on the degree
of dilution, the downstream receiving waters may show
similar peaks requiring adjustment of the sampling
frequency to detect these variations.
Heavy metals in many water and waste samples are
unstable. Precipitation, adsorption on silt particles and
container walls, and changes in valence state may occur
soon after sample collection. Standard practice includes
acidification with nitric acid at the time of sampling to
avoid these changes.
In order to properly characterize the metals present, it
-------
MONITORING - WATER
147
is essential that the analytical procedure be very specific
for the metal being measured. This specificity includes
determination of the physical state of the metal,
example, soluble vs. insoluble forms, as well as the
valence state of the metal. Iron and chromium are two
classic examples of the importance of oxidation in
metals testing.
Permissible levels of some metals in surface waters are
extremely low, requiring analytical sensitivity in the
microgram per liter range. These sensitivity requirements
often challenge the skill of the analyst.
Because of the necessity for determining compliance
with regulatory standards, a high degree of accuracy and
precision, at the low concentrations encountered, are
additional requirements placed on the analysis.
AVAILABLE ANALYTICAL METHODS
In the past, metals in aquous solutions were
determined by colorimetric procedures. While adequate
sensitivity can often be obtained by these methods, they
tend to be tedious and subject to many interferences. In
the dithizone procedures, for example, any or all of 17
other metals act as interference in the measurement of
the 18th.
Currently, atomic absorption spectroscopy is the most
prevalent method for metals analysis of water and waste
samples. A very large number of metals can be measured
with these instruments, and when solvent extraction or
other concentrating systems are used, sensitivity is
adequate for most monitoring purposes. In spite of the
versatility and simplicity of the instrument, two
limitations of atomic absorption should be mentioned.
Only one metal may be measured at a time, so that rapid
screening to characterize the metal content of the
sample is very time consuming, and secondly, only total
metal concentration is determined, since the flame
reduces all forms of the metal to the atomic species. In
spite of these limitations the advantages of AA make it
the method of choice in most laboratories (5). Recently
a number of procedures have been developed using the
cold vapor atomic absorption technique. The
determinations of mercury is the best known example of
this type of procedure. The familiar Hatch and Ott
method for mercury is based on the absorption by
mercury vapor in the ultra-violet range of the spectrum
(6). Arsenic and selenium can also be measured in this
manner, although the methods are not yet widely used.
It is likely that other metals may be determined by
flameless atomic absorption when the analytical
methods are worked out.
Atomic fluorescence, another variation of the
instrumental approach, shows promise of success for
certain metals not susceptible to measurement by
standard AA technique.
Emission spectroscopy overcomes the single-element
limitation of AA, since most emissions instruments can
be programmed to measure 20 to 30 elements
simultaneously on the same sample (7). This approach
offers excellent possibilities for screening samples to
determine the presence or absence of specific metals. As
in the case of AA, extraction or concentration of the
sample provides the needed sensitivity for most
purposes. However, the total metal concentration,
without oxidation state information, is produced by the
emission instruments.
Electrochemical methods, particularly polarography,
have long been used for the determination of heavy
metals (8). Before the advent of atomic absorption,
polarography was considered a preferable substitute for
colorimetric methods. The technique, however, did not
gain the wide acceptance enjoyed in Europe, and the
newer and simpler AA method has relegated
conventional polarography to only a few laboratories.
Recently, however, the anodic stripping polarograph is
being seriously considered as a means of measuring
certain metals (9). As with conventional polarography,
the oxidation state of the metal can be readily
determined, and the accumulation of metal on the
cathode permits excellent sensitivity. Commercial
instruments are now available which provide good
accuracy and precision, without the analytical expertise
often considered necessary for conventional
polarography.
A number of ion-selective electrodes have been
developed for specific metals. In general, the electrode
approach does not provide the necessary sensitivity for
monitoring purposes and these systems are largely used
to measure metals in concentrated solutions.
Improvements in sensitivity and selectivity might make
the electrodes suitable for continuous monitoring
situations.
A number of other instruments have been proposed
and are being used for the determination of metals.
Among these techniques are neutron activitation, mass
spectrometry, microwave plasma, X-ray fluorescence,
and others. The necessity for relatively complex
instruments, sophisticated data reduction systems, and
highly skilled operators tend to make these methods
unsuitable for routine analysis of a large number of
samples. While each has its enthusiastic proponents,
these instruments have not gained with acceptance at
this time.
QUALITY CONTROL
In any monitoring program the quality of the data
collected is extremely important. The significance of the
decisions made from the data requires that all analytical
results be as accurate as possible, within the constraints
of workload, available methods, and economy. The only
way to define and control the reliability of laboratory
results is through a well designed operational quality
assurance program (10). Such a program must include
the use of approved methods, the availability of suitable
equipment and instrumentation, the use of daily
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148
CYCLING AND CONTROL OF METALS
controls on analyst performance, and proper data
handling systems. The National Environmental Research
Center, through its Analytical Quality Control
Laboratory, regularly conducts round-robin studies to
establish the precision and accuracy of the methods used
by EPA laboratories. At the present time a study to
evaluate atomic absorption methods for ten metals is
being carried out by more than 100 participating
laboratories in EPA, the states, universities, and private
industry. The samples used in the study are prepared to
exact concentrations of each metal, covering the range
of expected levels in ambient waters and industrial
effluents. The final report, which will be available to the
public, will describe the standard deviation and bias of
each method, as well as the range and coefficient of
variation of the reported results.
In addition to conducting method studies, the AQC
Laboratory makes available a series of standard reference
samples for a variety of environmental monitoring
parameters, including heavy metals. These samples,
available without charge, can be used to evaluate
analytical methods, instrument, and analyst
performance, and can be used for intra-iaboratory
quality control.
SUMMARY
Monitoring for trace metals in the aquatic
environment involves source and near-source sampling,
as well as ambient monitoring for baseline data and
trend analysis. Data from studies by EPA and the
Geological Survey indicate that significant
concentrations of heavy metals exist in some locations,
requiring abatement of discharges. A number of
satisfactory analytical methods are available and in use
to determine metals in water and waste samples. Good
Laboratory quality is essential to the monitoring
program, and various manuals and reference samples are
available from EPA to assist in establishing and
maintaining efficient laboratory operations.
REFERENCES
1. Application for Permit to Discharge or Work in
Navigable Waters and Their Tributaries, Eng.
Form 4345-1, Department of the Army, Corps
of Engineers, Washington, D. C. 20314.
2. Kopp, J. F. and R. C. Kroner, Trace Metals in Waters
of the United States, U.S. Dept. of Interior,
FWPCA (Available from Nat. Env. Research
Center, Cincinnati, Ohio 45268).
3. Durum, W. H., J. D. Hern, and S. G. Heidel,
Reconnaisance of Selected Minor Elements in
Surface Waters of the United States, Geological
Survey Circular 643, U.S. Geological Survey,
Washington, D. C. 20242, October 1970.
4. Taylor, F. B., Trace Elements and Compounds in
Waters, Journal of the American Water Works
Assoc. 63:728,1971.
5. Methods for Chemical Analysis of Water and Wastes,
EPA, 1971 (Available from Nat. Env. Research
Center, Cincinnati, Ohio 45268).
6. Kopp, J. F., M. C. Longbottom, and L. B. Lobring,
Cold Vapor Method for Determining Mercury,
Journal of the American Water Works Assoc.,
64:20, 1972.
7. Kopp, J. F. and R. C. Kroner, A Direct-Reading
Spectrochemical Procedure for the Measurement
of Nineteen Minor Elements in Natural Waters,
Applied Spectroscopy 19:155,1965.
8. Ballinger, D. G. and T. A. Hartlage, Polarographic
Determination of Metals in Water, Wastes, and
Biological Samples, Water and Sewage Works,
September 1962.
9. Allen, H. E., W. R. Matson, and K. H. Mancy, Trace
Metal Characterization in Aquatic Environment
by Anodic Stripping Voltametry, Jour. Water
Pollution Control Fed., 42:573,1970.
10. Handbook for Analytical Quality Control in Water
and Wastewater Laboratories (Available from
Nat. Env. Research Center, Cincinnati, Ohio
45268).
-------
MONITORING OF SOLID WASTES
E. A. GLYSSON
The University of Michigan
Ann Arbor, Michigan
Monitoring, as defined by the American College
Dictionary, is "something that serves to remind or give
warning." As applied to solid wastes, monitoring may be
used to identify the quality and/or composition of the
wastes.
This might be expected to assess the resource potential
of the waste, its energy content, or the content of
material which might be recovered for recycling. Such
assessment would allow selection of the most suitable
method for solid waste processing and disposal.
The solid waste stream reflects all the substances that
are in use by the population from which it is derived. In
that sense then it can contain anything that can be
thrown away. Substances which pose hazards to the
environment and to the solid waste worker are included
in this material. Proper monitoring would lead to better
knowledge of these potential hazards and provide for
better control. Hazardous materials, generally speaking,
are in small quantities at any given time and are
sequestered in a large amount of other materials which
make up the majority of the refuse composition (1)
(paper 55 percent, metal 9 percent, glass 9 percent,
plastics 1 percent, food 14 percent, other 12 percent). In
this form they are most difficult to detect. Certain types
of hazardous materials may pose a danger to the solid
waste worker either during collection or at the
processing or disposal site (example, flammable or
explosive substances). Ideally a monitoring system
should be devised to detect such materials. From a
practical standpoint they constitute such a small number
of instances and amounts that they rightly or wrongly
are relegated to the classification of a calculated risk. (It
might be stated that most hazardous materials such as
explosives are prohibited from being deposited in the
refuse by local ordinances governing the collection and
storage of refuse.)
There is another area of monitoring, that involved
with solid waste disposal, where the presence of small
amounts of various substances can have an adverse effect
on the quality of the environment, particularly that
adjacent to the disposal site. Monitoring of the
discharges of a disposal facility are an example of this
problem.
The type of data needed is relative to the way in
which the information is to be used. For the most
efficient control of energy recovery systems
(incinerators), the calorific content, moisture content,
ash and noncombustible content are required. For the
recycling of metals and other materials it is necessary to
measure the quantity contained of the various fractions
to be recovered.
Monitoring for trace metals or materials deemed to be
hazardous or toxic would of necessity be quite selective
since it is necessary to pick out small amounts of such
substances in a large mass of material. The possibility of
hazardous material appearing at any time makes the
monitoring continuous. It would generally be considered
adequate to detect the presence (yes or no) rather than
the amount or quantity of a hazardous material.
The format of the information has to reflect the
manner in which it will be used. Continuous readout
data would be helpful in monitoring the material to be
fed to a continuously fed incinerator, since the
operation of the furnace requires response to its fuel
supply.
The format needed for evaluation of material for
recycling would not need to be continuous. It could be
intermittent, more to determine the potential, initially,
and later to determine if the recovery operation was as
effective as it was intended to be.
Accuracy requirements of a monitoring system vary
but in no case is it essential to be extremely accurate.
Combustibility or calorific content within 10 percent,
plus or minus, moisture within 5 percent, plus or minus,
are more than adequate for the control of an incinerator
based on fuel input. Measuring the metal content for
evaluating recycling potential or efficiency would
depend on how good the separation process was
expected to be and the accuracy of evaluation scaled
accordingly.
The accuracy required in monitoring the discharges
149
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150
CYCLING AND CONTROL OF METALS
from a disposal site would probably be more precise in
that they would have to detect smaller quantities of
materials which involve more sophisticated analytical
processes. (In the final analysis this type of monitoring is
actually easier than many of the others.) The accuracy as
a percentage would be adequate to plus or minus 10
percent in most cases. The frequency of measurement
would need to be often enough to detect a significant
change in effluent quality so that corrective measures
could be taken in time to prevent any serious impact on
the environment. This varies with the type of possible
pollutant and its form. Gases, for example, would be
monitored very frequently, if not continuously, whereas
ground water quality could be done much less often.
As to where monitoring is to be done, it should reflect
the need to respond to the results obtained. If the
determination is to be the basis of decision as to
collection and/or storage and perhaps recycling of
selected components, the monitoring would be done (a)
at the source (example, industry or residence) where
different modes of separation, storage or
containerization might be required, or (b) at the process
point (processing plant, landfill or incinerator) so that
changes could be made as necessary in methods of
operation. If monitoring of environmental quality by
detecting the possible effects of leachate or air pollution
derived from a disposal facility is desired, then the
disposal site itself or the area immediately adjacent
should be selected.
Monitoring techniques now in use vary rather widely.
With a few exceptions they are more qualitative than
quantitative. Most of the information obtained to date
has been as the result of the manual partioning of
representative samples of solid waste taken at the various
points described earlier. The selection of categories into
which the waste was divided being determined by the
uses to which the data were to be put.
Britton (2) has stated that a minimum size sample of
300 pound is needed for most studies of a general
nature. It was shown in this same study that a minimum
of 10, 300 pound samples is necessary from 500 tons of
waste to maintain a confidence interval of 90 percent.
(In measuring constituents by this method, very little if
any effort has been expended in measuring trace
elements, only the metals present in relatively large
quantities being reported. All others were grouped as
other or miscellaneous.)
Monitoring techniques for measuring metals and other
constituents of leachate, which may develop from
landfills, are being used in conjunction with observation
wells and lysimeters constructed in the areas
immediately adjacent and beneath the landfill. In general
these consist of some sort of sampling equipment for
taking intermittent samples for analysis by
chromatographic or other techniques. These techniques
are reasonably successful in measuring the changes which
occur in ground water adjacent to disposal sites and the
effectiveness of sealants and other measures to reduce or
eliminate leaching conditions. They are expensive to
install, maintain, and operate, especially considering the
length of time needed for monitoring in some instances.
Metallic ions such as iron, zinc, nickel, copper, and
sodium can be determined (3).
Equipment for monitoring of stack gases from
incinerators on a continuous basis is available but is
usually limited to participate determinations. This
equipment is expensive to install, maintain, and operate
and its reliability leaves something to be desired. Trace
metals can be detected in samples of dust but are not
usually analyzed routinely since air pollution codes are
at present concerned only with particulates per se. If and
when codes become more stringent with respect to
gaseous and other constitutents, more sophisticated
analysis will be used and trace metals may be included.
In some special industrial situations where hazardous
conditions exist (lead, mercury, etc.), these metals are
monitored routinely.
Continuous monitoring of solid wastes is a most
difficult task due to its variations in shape, composition,
and complexity. Several methods are in use and others
are under study and in various stages of development for
detecting and segregating various components from a
continuously moving stream of solid wastes. (It is
usually necessary to pre-process the waste by shredding
or grinding in some manner to produce a more uniform
particle size and to expose more of the waste.)
Magnetic separation of ferrous metals from the rest of
the waste has been in use for many years. This method is
relatively successful if the metal is accessible, and a
certain amount of entrapped and attached extraneous
material is acceptable (in the case of raw refuse). Metal
can be separated from incinerator residues without much
more treatment than tumbling over a coarse screen.
Rather complete separation of nonferrous metals can be
accomplished from certain types of waste (example,
residues from shredding automobile bodies) after
removal of ferrous metal magnetically. Other materials
are separated by such means as air classification, heavy
media flotation and differential melting of lower
temperature melting point metals (4). In this process
zinc, aluminum, stainless steel, red metal, and steel are
separated on a continuous basis. Rubber and glass are
by-products which can be segregated if a market is
available. To date no trace metals are segregated by this
process. If present they are considered as impurities in
the other metals.
There are several methods other than magnetic for
segregation and monitoring solid wastes on a continuous
basis under consideration and development. Material
might be monitored on the basis of its bulk density,
optical characteristics, fiber content, eddy-current
reaction, and impact characteristics to name a few.
Mechanical methods of monitoring on a continuous
basis are essential if the many idealized objectives
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MONITORING - SOLID WASTES
151
described earlier are to be accomplished. Unfortunately
each of the proposed systems have much to be done to
them before they will be ready for practical application
(5).
There is no practical continuous method available at
present for determining such characteristics as the
moisture content of a heterogeneous mass such as refuse.
The infra red scanning technique for example can only at
present measure the character of the surface and is
complicated by the presence of metals. The
measurement of the calorific content is very slow and
cumbersome by present methods and there seems little
likelihood of being able to improve the situation. No
continuous method of evaluation is available.
Alternatives to continuous monitoring for incinerator
operation might consist of separation of the
noncombustibles prior to some form of continuous
moisture determination which when coupled with
statistically rigorous information from prior testing
could be used to indicate the combustibility of the
material for control purposes.
Detection of trace metals in the refuse stream on a
continuous basis seems to be highly unlikely when
viewed from the present situation. If complete
processing were considered which includes a reliable and
efficient means of reducing the refuse to a uniform
particle size, and a reliable high velocity automatic
sorting device was available to separate the constituents,
then monitoring for the presence of trace metals as well
as other metals might be possible.
Several separation techniques have been developed and
are in various stages of application. The hydropulper
process separates fiber and performs several other sorting
operations resulting, among others, in a metal-glass
effluent which is further sorted optically. Air
classification, sorting by conductivity, photometric
methods, sorting by "bounce" are some of the several
methods besides the magnetic separation discussed
earlier which are being evaluated by various agencies and
individuals. In the main, these various methods need
testing and improving before they can be considered able
to handle economically and continuously such
diversified wastes as municipal refuse. There is every
reason to expect that the sorting techniques will be
improved and problems ironed out so that adequate
separation can be accomplished in the future.
Most monitoring of waste streams today are done
visually with adjustments being based on judgment and
experience. If an object is noted which should be
removed it may be taken out by hand. Hand sorting of
metal is still common in many salvage operations where
the value of the material is great enough to pay for its
removal. Visual monitoring of wastes at the disposal sites
(example, sanitary landfill) may indicate that the
material needs special handling to avoid difficulty in the
operation.
The laboratory techniques used to analyze the samples
taken from monitoring stations at landfills or at
incinerators as well as the setting up and operation of
the sampling equipment require a certain amount of
training and ability. Personnel who are assigned sampling
and analytical responsibility should be adequately
trained to carry out these tasks so that the results can be
depended upon. This type of training is somewhat
specialized and would require knowledge of basic
chemical laboratory technique and sampling procedures.
Such training can be obtained in several ways, ranging
from formal college training to short courses specially
taught thru some governmental agency.
In general monitoring has been conducted only when
required by some regulatory agency in order to assure
compliance with a regulation or environmental quality
criteria. The exceptions are those facilities where
research or demonstration projects are being conducted
to determine the effects of some operation. Under these
circumstances monitoring can be done by the waste
producer to assure, for instance, that no hazardous
materials enter the solid waste stream. This could apply
equally well to householders and to industry. The level
of monitoring would vary widely from one extreme to
the other. This would be monitoring prior to collection
of the waste while it is still at the point of generation.
Monitoring at the point of processing or disposal is more
likely to be done by the agency operating that facility
especially if the information is to be used to modify the
operation of the facility. If environmental quality is the
reason for monitoring, then the operator of the facility
may be responsible for the monitoring or it may be done
directly by the regulatory agency itself.
The data gathered certainly will be useful locally. Its
wider spread usefulness may consist more of indicating
trends and variations from place to place and to indicate
effectiveness of various treatment and monitoring
methods. Such trends and variations would likely be of
interest to a state or federal agency, especially those
involved with environmental quality.
If the generator of the waste is the one who benefits
from the information gained by monitoring of his solid
wastes, then obviously he should bear the cost. If it is
necessary to monitor the wastes on his premises to
protect his employees or the environment, then he
should also bear the cost as a part of his costs of doing
business. Since the collector of the wastes in some cases
serves as an employee then he can expect some
protection as well from the monitoring of the wastes he
picks up.
The disposer or processor of the waste may be
responsible for payment for monitoring if he is the
beneficiary of the information as in controlling his
operation. He may also be required to provide
information supporting his position in protecting the
environment in which case he will have to pay for the
installation, sampling, and testing required in the
monitoring system. If the monitoring is being done to
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152
CYCLING AND CONTROL OF METALS
protect the environment, then the regulatory agency
responsible for environmental control in the area must
maintain surveillance and monitoring equipment of its
own in order to assure that protection is being provided.
The costs of such operation would most likely be paid
for by the regulatory agency from public funds. There
have been instances where those being regulated were
expected to pay for such monitoring. In any situation
involving interstate jurisdiction a federal agency would
probably be involved. In this case the U.S.
Environmental Protection Agency would be expected to
monitor the local agencies' operations and would serve
as a collection and distribution medium for data and
information of value to other states and agencies.
SUMMARY
In summary it can be said that at present the
monitoring of solid wastes in general is far from
adequate and for trace metals is hardly considered. More
must be learned of the importance of trace metals from
solid wastes upon the quality of the environment.
Studies to date have not indicated that trace metals are a
problem from this source (6), but more work needs to
be done.
REFERENCES
1. Environmental Data Handbook, American Can Co.,
Feb. 1972.
2. Britton, P. W., Improvising Manual Solid Waste
Separation Studies, Journ. of San. Engr. Div.,
ASCE, Vol. 98, No. SA5, Oct. 1972.
S.Fungaroli, A. A. and R. L. Steiner, A Study of
Sanitary Landfills — Final Report, Drexel
University, Nov. 1969.
4. Glysson, E. A. and J. Packard, The Problem of Solid
Waste Disposal, Ingenor 9, University of Michigan,
Nov. 1972.
S.Golueke, C. G., Recycling and Reusing Resource
Residues, Compost Science, Jour, of Waste
Recycling, 12(3):4-9, May, June 1971.
6. Zanoni, A. E., Ground Water Pollution From Sanitary
Landfills and Refuse Dump Grounds, A Critical
Review, Dept. Natural Resources, Madison,
Wisconsin, 1971.
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MONITORING FOR TRACE METALS IN FOOD
E. O. HAENNI
U. S. Department of Health, Education, and Welfare
Washington, D. C.
INTRODUCTION
Monitoring for trace metals in foods poses problems
of much greater scope and complexity than casual
consideration might suggest. It is the purpose of this
paper to at least delineate these problems and to indicate
progress in their control. The privilege of giving the
presentation on this subject of major significance to the
Food and Drug Administration's area of responsibilities
is sincerely appreciated. This report will deal with the
past and current situations and the business ahead, with
particular emphasis on the analytical aspects of the
subject. Although this seems an excessively ambitious
coverage in the brief space available, an understanding of
the subject problem as it has challenged the Food and
Drug Administration requires at least some such
approach to develop an understanding of the analytical
and surveillance situations as of today.
This presentation will be restricted primarily to the
analytical problems and surveillance activities of FDA in
this field, but these problems are quite common to other
agencies responsible for control of toxic metal
contaminants in foods and, accordingly, should suffice
to illustrate the general situation.
Aside from the sporadic incidents which are always
upsetting our well-laid plans, the primary problems in
contamination of foods by toxic metal residues
recognized prior to World War II were associated with
use of insecticides containing copper, mercury, arsenic,
and/or lead. Development of methods, surveillance, and
regulatory programs constituted major efforts of the
Food and Drug Administration and of the responsible
state and local regulatory agencies. For example, during
the apple harvest season the entire inspectional and
analytical staffs of FDA field stations in primary
growing areas were engaged in surveillance of apples for
lead arsenate residues. Cases of apples awaiting analysis
were then stacked from floor to ceiling at the FDA
Cincinnati Laboratory where I worked. Similarly,
primary resources of field stations in other major crop
areas were assigned to surveillance for residues of lead
arsenate and of the other metal-based insecticides then
prevalent. At that time a major proportion of the staff
at the Washington Headquarters' Division of Food was
engaged in research to improve the sensitivity, accuracy,
and reliability of analytical methods for the
determination of such residues. The enormous growth in
the use of organic pesticides following World War II
posed new much more complex residue problems. The
consequent major displacement of the conventional
metal-based agricultural poisons led to the virtual
discontinuance of research on determination of toxic
metals in foods, and resulting loss over the years in the
food laboratories of resources, both personnel and
equipment, adapted to trace heavy metal analysis.
However, the occasional diversion of surplus seed wheat
treated with mercurial fungicides into the commercial
wheat supply stimulated attempts to determine trace
levels of mercury above background. The FDA (1)
published the technique for measurement of mercury by
cold vapor flow absorption cell as early as 1966. Its
adaptation to determination of submicrogram quantities
of mercury in wheat, fish, and eggs (2, 3) gave initial
successful results with a sensitivity of 0.01 ppm.
However, the subsequent inability to acquire reagents
sufficiently free of mercury and the very low levels
found in the samples initially analyzed (0.01 to 0.03
ppm) discouraged continuance of the research.
Nevertheless as early as 1967, FDA checked the mercury
content of a number of total diet categories by neutron
activation analysis (4), finding values of the same order
as those cited above. It is interesting to speculate if the
mercury contamination problem in fish might not have
been discovered earlier if the stringent sensitivity
requirement for the specific wheat problem had not
discouraged further analytical research on mercury at
FDA.
The approach to food supply surveillance, the FDA
total diet or market basket survey, originated for
radionuclide surveillance (primarily 90Sr) was adapted
and proved effective for pesticide residue monitoring,
and has now been expanded for use again as one means
of surveillance for toxic metals. It is manifestly
153
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154
CYCLING AND CONTROL OF METALS
impossible to ensure freedom from toxic residues of
every lot of every product in a food supply as enormous
and as diversified in kind, source, processing, packaging,
and distribution as that of the United States. The most
effective surveillance for overall safety which practicable
resources can provide is periodic examination of a
representative total diet for potential toxic residues,
complemented by analysis of specific commodities in
which occurrence of particular residues is most probable.
The concept and use of total diet or market basket
surveillance have been described in detail (5). It will
suffice here to summarize this FDA program currently as
periodic collection and analysis, as prepared for
consumption, of twelve composited food categories
representative of the two-week diet of a 15 to 20 year
old male for the northeastern, southeastern, central and
western regions of the United States.
At this point, it seems appropriate to emphasize that
the brunt of the surveillance and monitoring work is
borne by the District Laboratories of the FDA. The
function in the Division of Chemistry and Physics,
Bureau of Foods, is primarily to undertake necessary
analytical evaluation and/or development work in
support of surveillance operations and to provide highly
specialized and sophisticated analytical support services,
such as neutron activation analysis. It should be
emphasized that the district laboratories also contribute
to the analytical research and evaluation, both through
original work and through conduct of and participation
in collaborative studies. These district functions are
greatly facilitated by the advice of competent outside
scientists assigned to each district laboratory as
consultants.
THE CURRENT SITUATION
As is well known, the sudden resurgence of the
problem of toxic metals in foods arose with the
Minamata incident in Japan and the findings of high
levels of mercury in fish in Sweden and in Lake St. Clair,
Canada. There was an immediate need for analytical
methods applicable to determination of inorganic
mercury and of the more toxic methylmercury found in
Sweden to be the predominant form of occurrence in
fish. Cold vapor or flameless atomic absorption is most
commonly used for total mercury determination, while
the Westb'6 procedure (6) appears quite reliable for
determination of methylmercury. An international
collaborative study (sponsored by the Society for
Analytical Chemistry and the AOAC) is in progress and
should establish the degree of reliability of the various
mercury methods involved. A comprehensive report on
surveys of mercury in fish and other foods was presented
at the recent meeting of the AOAC by Simpson and
Horwitz (7). I shall summarize that presentation briefly.
It involves typical application of the combined
approaches of total diet and individual commodity
surveillance. It also exemplifies the analytical problems
in trace metal monitoring of the food supply and in
evaluation of the toxicological effects. The survey of
canned tuna was undertaken by FDA in cooperation
with the National Canners Association and the National
Oceanographic and Atmospheric Administration. The
results showed that about 4 percent of the more than
2000 samples examined exceeded the FDA action
guideline of 0.5 ppm, the average being 0.25 ppm. It was
also shown that the larger the fish the higher was the
average mercury level and the proportion exceeding the
guideline. A similar observation was made with respect
to Pacific halibut by the National Marine Fisheries
Service.
FDA undertook a survey of swordfish as well as of 19
other species of commercial fish and shellfish. The
extensive findings 95 percent of high levels of mercury
in swordfish exceeding the action guideline of 0.5 ppm
necessitated the FDA ban on swordfish distribution
(Table 1). In contrast, of the 19 other species surveyed
(Table 2), only 4 (bonita, cod, mackerel, and snapper)
showed a significant percentage exceeding the guideline
(Table 3). In these cases the analytical method employed
was the cold vapor atomic absorption method of the
Fisheries Research Board of Canada or a similar
procedure (8). In addition, in cooperation with 45
states, the Tennessee Valley Authority, and the
Environmental Protection Agency, surveys of fish from
fresh water fishing areas throughout the Unites States
were completed. About 40 percent of all samples
examined exceeded the 0.5 ppm guideline. Closure of
fishing areas and/or warnings against eating fish taken
from polluted waters were issued by 16 of the states
covered in the survey. Import samples of freshwater
species showed about the same proportion (45 percent)
containing excessive mercury.
TABLE 1 DISTRIBUTION OF Hg LEVELS IN
SWORDFISH ABOVE 0.5 ppm
GUIDELINE
ppm Hg found % of total samples
0.50-0.74
0.75-0.99
1.00-1.24
1.25-1.49
1.50-1.99
2.00-2.99
> 3.00
13.7
33.2
26.5
15.3
8.5
2.4
0.3
TABLE 2 SEAFOOD ANALYZED FOR Hg
Bonita
Clams
Cod
Crab
Flounder
Haddock
Hake
Halibut
Herring
Lobster
Mackerel
Oysters
Perch
Salmon
Sardines
Scallops
Snapper
Trout
Whitefish
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MONITORING - FOOD
155
TABLE 3 SEAFOOD WITH X).5ppmHg
Type
Bonita
Cod
Mackerel
Snapper
Mean ppm
0.30
0.09
0.12
0.31
%> .5 ppm
10
3
3
18
TABLE 4 NAA FOR MERCURY IN FOODSTUFFS
(ppb)
Commodity
Flour
NF Dry milk
Sugar
Potatoes
Beef
Chicken
Shrimp
Beef liver
Eggs
Whole milk
No. samples
28
33
22
33
23
24
32
22
33
23
Median
<3
10
<3
3
3
3
14
3
<2
<1
Range
<3-6
<4-27
<3-10
<1-15
<2-7
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156
CYCLING AND CONTROL OF METALS
TABLE 5 NAA FOR MERCURY IN TOTAL DIETS
Mercury cone, (ppb): 1972
rooa nem
Dairy products
Meat, fish, poultry
Grain, cereal producl
Polatoes
Leafy vegetable
Legume vegetable
Root vegetable
Garden fruits
Fruits
Bait.
<1
30
3
3
5*
<2
2
2
<2
Bos.
<1
27*
8*
8*
5*
<1
<1
2
2
K.C.
<1
8*
5
2
3*
<2
<1
<1
3*
Minn.
3
9
<2
3
<1
<1
<1
<1
<1
L. A.
2
27
< 2
< 1
< 1
< 1
< 1
< 1
< 1
*Avg. values.
animals. A special problem was posed by the desire to
study localization of mercury residues in discrete sections
of rat brains following ingestion of methylmercury. Only
a few milligrams of sample could be supplied, but by
utilizing NAA we were able to supply the required data.
For the hundreds of blood analyses required, fortunately
the rapid Magos procedure (13) has proved reliable.
I have chosen to devote what may seem an excessive
proportion of time to the mercury problem. This is,
partially, because more information is available on the
analytical methodology and on the occurrence of
mercury in foods. But more significantly, as indicated
earlier, the experience with mercury illustrates the
gamut of analytical problems to be anticipated in the
monitoring of trace metals.
There is need for practicable methods of adequate
sensitivity to monitor individual food commodities; for
methods of a sensitivity an order of magnitude better to
monitor composite total diet categories of commodities;
for methods applicable to determination of the normal
background level of the metal in foods; for methods for
identification and determination of the various forms in
which a toxic metal residue occurs in foods; for practical
methods applicable to the often minute samples that are
the only ones available in lexicological studies; for
automated methods to facilitate analysis of a large
number of samples. Necessary to, and perhaps eclipsing,
all of the preceding is the need for studies of methods of
sample preparation and sample dissolution or reduction
to make the products amenable to the ultimate
determinative phase without loss of the toxic residue or
adventitious contamination of the sample. There is also
need to be extremely cautious to avoid arousing undue
public alarm and pressure to undo fictitious knots with
consequent diversion of limited resources from really
critical problems. As we face the broader monitoring
problem, it is obvious that we are also in need of reliable
multielement methods.
In recognition of the prevasiveness and possible health
hazard of many metal residues, FDA lexicologists
developed a list of metallic elements posing or
potentially posing a problem in groups in an
approximate order of decreasing estimated significance
(Table 6). It should be pointed out that some elements
within a group may be included not in relation to their
intrinsic degrees of toxicity but in relation to the effect
of their presence on the toxicity of other elements
therein; for example, in the first group, zinc is included
because of the significance of the zinc-cadmium ratio to
the toxicity of cadmium. Beyond these, FDA is
concerned with Ni, Co, V, Mn, Mo and up to a total of
twenty or more metals occurring in the environment,
the forms, concentrations, and lexicological significance
of which are virtually unknown. This broad spectrum of
metals, in conjunction with the variety of analytical
needs cited, has posed a monumental task which neither
FDA nor any other organization has adequate resources
in personnel and equipment to complete as soon as is
desirable. In the face of the urgent need and the lack of
enough chemists experienced in trace metal analysis in
foods, FDS is undertaking to expedite progress by
reassigning a cadre of chemists from other important but
lower priority projects to work with those experts
available in methods development; soliciting outside
contract support both in studies of potential
multielement techniques for the metals of primary
concern and in evaluation of any existing methodology
for metals of secondary concern in application to food
analysis; and utilizing, as available, methods recognized
as of less than adequate sensitivity, to undertake total
diet and individual commodity surveillance in order to
avoid repetition of the mercury experience, that is, the
failure to discover an existing excessive contamination
situation while resources are all devoted to refinement of
techniques.
TABLE 6 METALS OF CURRENT CONCERN
GP I - Pb, Hg, Cd, As, Se, Zn
GP II - Be, Ge, Sb, Tl, Cu, Cr, Sn
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MONITORING - FOOD
157
A special problem of concern is the hazard due to
migration of toxic metals from glazed pottery into food.
Primary attention has been given to contamination by
lead and cadmium. The test procedure for the leachable
metals involves exposure of the vessels to acetic acid and
determination of the extracted lead and cadmium by
atomic absorption spectrometry. A field surveillance
program has revealed few instances where domestic
products have exceeded the interim action guidelines of
7 ppm leachable lead and of 0.5 ppm leachable
cadmium, but these have been exceeded by a significant
proportion of imported pottery. A limited survey of
cadmium leachable from enamelware again has revealed
no problem with domestic products, but about one-third
of the imports exceeded the interim guideline during the
past year.
Another problem of special concern has been
occurrence in evaporated milk of higher than tolerable
levels of lead. This is, of course, a matter of particular
significance because of its extensive use in infant
formulas and because of evidence that young children
absorb and retain lead more readily than do adults^ In
order to evolve a reliable method foFThe determination
of lead in evaporated milk, FDA in cooperation with
industry laboratories undertook a collaborative study of
an atomic absorption and of an anodic stripping
voltammetric procedure (14). The results by atomic
absorption at levels of 0.16 ppm and above, including
the range of special interest up to 0.27 ppm, were quite
satisfactory. Insufficient results have been received for
evaluation of the electrochemical method, but
preliminary results indicate it may prove superior at
levels below 0.16 ppm. Meanwhile, the industry has
made much progress in modifying can closure solders to
reduce the contamination.
In addition to the cited mercury determination using
flameless atomic absorption spectrometry (8), the
following analytical procedures have been
collaboratively studied and adopted as Official, First
Action by the AOAC in 1971 and 1972:
Lead in evaporated milk (14)
Lead in fish (15)
Lead in plant and animal products (16)
Lead and cadmium leached from glazed ceramic
surfaces (17)
Cadmium in foods (18)
Meanwhile FDA studies are in progress on
multielement methods for mercury, arsenic, and
selenium in total diet samples by NAA; on mercury,
arsenic, selenium, cadmium, and lead in individual
commodities by atomic absorption spectrometry; or
lead, zinc, cadmium, tin, and copper in commodities by
anodic stripping voltammetry; and on cadmium, zinc,
and copper in toxicological samples (ppb range) by
atomic absorption spectrometry utilizing the heated
graphite atomizer accessory.
In conjunction with contract work to extend and
expedite coverage of the problem on the metals of
current concern, a preliminary limited service contract
has issued for study the applicability to food analysis,
for some twelve or more metals, of the technique of
radio frequency-induced plasma excitation emission
spectrometry. Depending on the results of that study, it
is being recommended by the Office of Science that a
full-scale contract proposal be solicited for such work.
Similar recommendations are being made for study of
the applicability to food and biological materials of
existing methodology for beryllium, germanium,
antimony, thallium, copper, tin, and chromium. The
objective is to select the best immediately available
procedures for use in initial surveillance and for further
refinement as necessary.
During the current fiscal year surveillance programs
will be instituted on mercury, lead, and cadmium in fish;
on cadmium in a variety of foods; and on mercury,
arsenic, selenium, lead, cadmium, and zinc in total diet
samples. Although the current procedures for the total
diet analysis are not of the ultimate sensitivity required,
the program will serve to disclose any serious
contamination problems.
THE BUSINESS AHEAD
It is apparent from the foregoing that a most
formidable task still faces us in the development of
methodology and an even greater one in respect to the
chronic toxicity and interactions of the less familiar
metals. The relationship between the analytical
requirements and the toxicological needs seems
inevitably to end up in the old chicken-or-the-egg
conundrum. The chemist asks what analytical sensitivity
the toxicologist requires and the latter asks how much of
the metal is there! Fortunately, the advent of the
National Center for Toxicological Research will greatly
expedite the setting of the goals which the analytical
chemist must achieve. During the next fiscal year we
anticipate that we should be able to develop enough
surveillance data to disclose any patently significant
unrecognized contamination of the food supply by the
metals listed in Groups I and II above. If fiscal year 1973
contract resources exceed our anticipated minimum it
should be possible to similarly deal with all of the
twenty or so metals of potential concern.
The special problems must engage our attention very
soon. One is a large scale survey of the diet of inner city
children for lead, to permit evaluation of the significance
to the elevated lead levels in their blood of dietary
intake in relation to known adventitious sources
(automobile emissions, lead paints, lead water pipes).
Another problem relates to the significance to the diet
contamination of the use of sewage sludge as fertilizer in
growing crops and forage. A preliminary investigation of
such use in the Chicago Sanitary District revealed that
soybeans so cultivated contained up to 1 ppm of
cadmium. It is apparent that a survey of the extent and
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CYCLING AND CONTROL OF METALS
consequences of that agricultural practice is essential.
How short a time it seems since analytical chemistry,
and particularly elemental analysis, was being relegated
to that class of routine operations offering no more
creative challenge! Only now are we beginning to
appreciate that we didn't know enough about the
problems to even recognize them and that seemingly
inert and innocuous substances can be facilely converted
in the biosphere to potent hazards.
REFERENCES
1. Schachter, M. M., JAOAC 49, 778, 1966.
2. Pappas, E. G., and L. A. Rosenberg, ibid., 49, 778,
1966.
3. Pappas, E. G., and L. A. Rosenberg, ibid., 49, 782,
1966.
4. Corneliussen, P. C., Pesticide Monitoring J., 2, 140,
1969.
5. Duggan, R. J., and F. J. McFarland,ibid, 1,1, 1967.
6. Westoo, G., Acta Chem, Scand., 21, 1790, 1967.
7. Simpson, R. E., and W. Horwitz, 86th Annual
Meeting of the AOAC, Washington, D. C., Oct.
9-12,1972.
8. Munns, R. K., and D. C. Holland, JAOAC 54, 202,
1971.
9. Jervis, R. E., D. Debrun, W. LePage, and B.
Fiefenbach, National Health Grant Project No.
605-7-510, University of Toronto, Canada,
Progress Report, July 1970.
10. Somers, E., Proceedings of the Symposium, Mercury
in Man's Environment, Royal Society of Canada,
Ottawa, 1971.
11. Kolbye, Jr., A. C., Science 175,1192,1972.
12. Tanner, J. T., M. H. Friedman, D. N. Lincoln, L. A.
Ford, and M. Jaffee, ibid., 177, 1102, 1972.
13-Magos, L., and T. W. Clarkson, JAOAC 55, 966,
1972.
14. Moffitt, R. A., G. E. Huskey, R. G. Scholz, R. J.
Gajan, J. A. Fiorino, and A. Woodson, 86th
Annual Meeting of the AOAC, Washington,D.C.,
October 9-12,1972.
15. Gajan, R. J. and D. Larry, JAOAC, 55, 727,1972.
16. Hoover, W. L., ibid., 55, 737, 1972.
17. Franco, V. and B. Krinitz, 86th Annual Meeting of
the AOAC, Washington, D. C., October 9-12,
1972.
18. Gajan, R. J., J. H. Gould, J. O. Watts, and J. A.
Fiorino, ibid.
-------
DIMENSIONS OF MONITORING
R. P. OUELLETTE AND J. W. OVERBEY II
The MITRE Corporation
McLean, Virginia
INTRODUCTION
The purpose of this presentation is to ask questions,
not to provide answers. Our hope is that by the
presentation of half-baked ideas we can stimulate the
thinking of the scientific community toward an
improved view of the environmental monitoring process.
This will be a study of an extreme and a technical
caricature. We intend to pollute your mind. What
follows will be a series of random snapshots relevant to
the concept of monitoring the environment of our
nation.
A guiding principle and a pervasive note throughout
this presentation is the following. Monitoring networks
yield vast amounts of raw data which must be
transformed into usable information by a filtering
process which generally involves a complex transfer
PERCEPTION
function. This is of paramount importance since
monitoring systems exist in support of the decision
making process for recommending actions. This process
feeds on information not data. For monitoring
networks to provide the pertinent information, we
must adopt a systems approach in designing these
networks.
THE ENVIRONMENT SYSTEM
One often hears that no systematic approach is applied
to the solution of our ever-changing environmental
problems. This lack of systems approach might result
from the fact that we are dealing with a complex system
which often follows no clearly predictable pattern.
As illustrated in Figure 1, the total environment
includes all conceivable attributes and interactions in the
ASSESSMENT
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ECOSYSTEMS
• YIELD
• BLIGHT
Figure 1. The total environment.
159
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160
CYCLING AND CONTROL OF METALS
universe. These are too all-encompassing to treat in a
comprehensive way. Therefore, subportions of the
environment are usually selected for study since only by
creating such partitions can any element be described
easily.
MULTIMEDIA ASPECTS OF POLLUTION
When the environment is partitioned for study, we
often fail to remember that many pollutants move from
one media to another in a circular fashion as part of a
natural geocycle or they are forced by the control action
of men. Pollutant control programs must consider these
interactions so as not to remove pollutants from the air,
for example, only to put the waste into a stream or to
dump it thoughtlessly on the land (Figure 2).
WEATHER
PLUME DISPERSION ,
PARTICLE FALLOUT
DIFFUSION. AND REACTION
WASHOUT Br
LAND
SOLID WASTE
RU N-O FF
EROSION
WATER
BIO-DEGR A DA BLE EFFLUENTS
NUTRIENTS
SEDIMENT
Figure 2. Interaction of pollutants with the three
environmental phases.
We live in a closed system and we can safely conclude
that entorpy is ever increasing. This leads to a
seemingly natural conclusion that we cannot eliminate
pollution, and that our chosen actions result from
considering the pollutant side effects of many
alternatives and then selecting the action having the least
effective form of pollution in the least dangerous media.
Are we then faced with a situation where the
effectiveness of our control technology will
systematically fall behind because of population growth
and industrialization?
The situation so depicted is not hopeless. We can learn
to live in a polluted world. We will have breakthrough in
technology; but, more important, we can slow down and
even reverse the process. Some of the options include,
but are not limited to, product or process changes and
energy demand curtailment. Information needed to
guide these policy decisions and to evaluate their
effectiveness is provided by environmental monitoring
systems.
MONITORING PURPOSES
We see at least four basic types of monitoring systems
currently in use (Figure 3).
l.A surveillance system for enforcement actions in
support of compliance and regulatory activities; this
tends to be a source monitoring system;
2. An administrative system using environmental data
for planning, budgeting, and assessing the impact of
control programs;
3. An ambient monitoring system measuring the status
of the environment containing a baseline subsystem
and an early warning subsystem. This early warning
subsystem monitors short-lived phenomena or episode
and trends;
4. Lastly, a research and scientific system aimed at
supporting effects studies and mathematical modeling.
This system supports research activities which are
usually established on a specific problem basis,
including the identification of new pollutants, the
in-depth study of problem areas, and the
establishment of cause-effect relationships.
A great number of variations and refinements can be
conceived. We believe that the above taxonomy will be
useful in the following discussion.
Data collected by means of monitoring programs
provide the raw data translatable into valuable
information for:
1. The continuing assessment of the effect of pollutants
and pollution on man, the natural and the modified
environment.
2. The detailed study of pollutant formation,
interactions, synergisin, and patterns.
3. The development, establishment, review, and
enforcement of criteria, ambient standards, and
industry performance standards.
4. The evaluation of the effectiveness of adopted control
procedures and preventive measures (control devices,
institutional modifications, monies, etc.).
5. Planning resources used and product and process
changes in order to minimize environmental impact.
6. Defining the need, direction, and intensity of future
research programs.
CHARACTERISTICS OF MONITORING SYSTEMS
In spite of the fact that we have identified at least four
types of monitoring systems, the tendency is to use
similar instrumentation, techniques, and procedures in
all cases. The result is that the objective of none of these
UNIVERSE
ADMINISTRATIVE
SCIENTIFIC
ENFORCEMENT
Figure 3. Overlap in monitoring systems.
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ENVIRONMENTAL FORECASTING
161
^Sv~\A T T R 1 B U T E S
SYSTEM ^^x.
SCIENTIFIC
ADMINISTRATIVE
ENFORCEMENT
AMBIENT
GRID SIZE
RESOLUTION OR
AREA COVERAGE
SMALL
LARGE
LOCALIZED
MEDIUM
ORIENTATION
GRADIENT
AMBIENT
SOURCE
AMBIENT
ACCURACY
MAX
M IN
M ED
MED
COVERAGE
(SPACE- TIME)
SPECIFIC
SYSTEMATIC
BIASED
SYSTEMATIC
DURATION
SHORT TERM
LONG TERM
SHORT TERM
SHORT &
LONG TERM
RESPONSE
LONG
IN-BETWEEN
SHORT
INTERMEDIATE
Figure 4. Characteristics of monitoring systems.
monitoring programs is satisfied in an optimal fashion.
Figure 4 shows some important attributes for each of
the four types of monitoring systems previously defined.
The idea is not to provide a comparative analysis of the
different systems, but to convey the wide range of
attributes and the far reaching consequences of such
requirements.
THE MONITORING PROCESS
Figure 5 identifies some important considerations at
each step of the monitoring process; from the original
concept to the end use of the information obtained. The
attempt is not to provide a catalog or a check list, even
though this would be a worthwhile project, but rather to
indicate that a dynamic re-evaluation of each and every
monitoring system, network, and project is called for in
the light of the concepts identified in Figure 5.
MEW A AND POLLUTANT EFFECTS
Media and pollutants, because of their varying
characteristics, often define to a large extent the
monitoring concepts selected and the instrumentation
used, as well as the method of data analysis and
presentation.
For example, Figure 6, fluid media move at varying
speeds and are at least three dimensional. The velocity,
temperature, and natural or induced stratification of the
fluid seems to collaborate closely in inhibiting the
attempts of the investigator to collect a meaningful
sample. The area sustained by the sensor is an ill defined
space in terms of volume and boundary. This condition
frequently exists to the point of rendering analysis
technically impossible.
The environment or the presence (known or
unknown) of modifying factors including chemical and
biological actions and reactions in a sample are especially
relevant. This is particularly true in the case of
integrated or grab samples. The presence of texture is an
additional complicating variable.
Obviously, the measurement of rare populations, trace
pollutant, or extreme values must be approached in a
different manner than the ubiquitous pollutants which
have more or less constant concentration values that lie
in the middle of the operating range of the measuring
device.
The monitoring network designer must surmount the
difficulties imposed by the pollutant and media
characteristics before the network can become
operational and provide data.
SYSTEM QUALITY ASSURANCE CONSIDERATIONS
We have accumulated and computerized vast stores of
environmental measurements. Environmental monitoring
networks are growing as rapidly as pollution itself. Still,
PURPOSE
ORIENTATION SPECIFICITY
RESOLUTION SENSITIVITY
DURATION ACCURACY
TIMELINESS INTERFERENCES
MFA1IIPFMFNT
SCALE
RANGE
PRECISION
RELIABILITY
REP
RESENTATION
QUALITY CONTROL ACCEPTABILITY
REFERENCE STD
COMMONALTY
COMPATIBILITY
COVERAGE
MEDIA
• SPATIAL
• TEMPORAL
• FUNCTIONAL
MAINTAINABILITY EDITING
CALIBRATION VALIDATION
PROCESSING
UTILITY
IMPACT
PLANNING
MANAGEMENT
DOCUMENTATION ENFORCEMENT
STANDARD
Figure 5. The monitoring process.
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162
CYCLING AND CONTROL OF METALS
OBSERVATIONS
STAGNANT/TURBITY/DEPTH/LOW FLOW
DECAY-BACTERIA/LEACHING
DEPTH/VEGETATION EFFECT/MATRIX/TEXTURE
OBSERVATIONS
RARE OCCURRENCE
SIZE/REACTIVITY
RANGE OF CONCENTRATION
AIR
FLUIDS WATER
SOLID WASTE
SOIL/1AND
POLLUTANT
METALS
PARTICULATE
S02
Figure 6. Media and pollutants define the monitoring
system to be selected.
when we review our achievement (as scientists) in the
field of monitoring, we are left unsatisfied with the
result.
We venture to diagnose that a lack of systems
approach to data acquisition and verification is at the
root of our problems. Figure 7 is an attempt at
introducing order in monitoring system design
considerations.
Acquisition
Siting knowledge is one of the limiting factors in
monitoring systems. If the accuracy desired and the
range of the parameters are known, it is easy to estimate
the required number of stations per unit area. The
technique usually used is an inverse t-test.
Unfortunately, findings from such studies have shown
that the number of stations required is usually beyond
economic and logistic feasibility. Mobile and/or
moveable stations appear to be a method, with some loss
of information, to increase the virtual number of
stations almost infinitely.
The grid size or the interstation distance can be fine or
large. Equally important, the grid can be systematic, that
is every point of a virtual projected lattice is occupied by
a station, or it can be totally random or biased to
measure a specific source or a specific stream localized in
space and time. Systematic sampling can be through a
uniform or exhaustive enumerative approach, or it can
use the transect approach.
Rules of thumb are available to assist in the location
of sampling stations in terms of height above a fixed
level (example, sea level, ground, etc.) as well as for
avoiding the effects of interferences (man-made
structure, lake, source). Unfortunately, selection of
sampling station siting has been in the past dictated by
the availability of specialized facilities. For instance, it is
not known to this day how many air quality monitoring
stations located on flat rooftop fire stations essentially
record a carbon monoxide time series generated by
ACQUISITION
SYSTEM
DESIGN
CONSIDERATIONS
SITING
SAMPLING"
DESIGN
EXTENT
GRID
NUMBER OF STATIONS
MOBILITY
HEIGHT
LOCATION-
PLATFORM-
RANDOM TRANSECT
BIASED
ABOVE GROUND/WATER
IN GROUND/WATER
ABOVE SEA LEVEL
SOURCE
AMBIENT
BACKGROUND
INSITU
FIXED
,TIME
INTERVAL
VARIABLE
•TIME
.INTERVAL
REMOTE
^CONTINUING
PERIODIC
/PROPORTIONAL,
^-THRESHOLD
^SEQUENTIAL
^SPORADIC
-FIXED INTERVAL
-NESTED
-CROSSED
-AMPLITUDE
^VARIANCE
VARIABLE
VERIFICATION
CALIBRATION
.UNIT
ORDINAL
/""" ^-CARDINAL
STANDARDS^-CERTIFICATION-ROUND ROBIN
^REFERENCE
Figure 7. System quality assurance considerations.
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ENVIRONMENTAL FORECASTING
163
trucks responding to fire alarms rather than the ambient
carbon monoxide level.
The first order and generally the gross level criteria of
location will usually be decided by the purpose of the
monitoring program which include background,
ambient, or source monitoring. The more detailed
question of measuring in-situ or from a remote site
(whether a few feet away, a plane, a balloon, a satellite)
is complicated by the fact that the distribution of
pollution is nonuniform within the media. Remote
sensing usually measures total burden, a column of
pollutant (example, from the ground to the platform),
but can also be used to take slice measurement across a
volume.
Let us turn now to the sampling design. We see this
concept being dominated by temporal aspects: time
interval between measurement, averaging, or integration
time and eventually reporting time. The interval between
measurements can be fixed or variable. Fixed time
intervals are commonly used by continuous and periodic
sampling devices. A host of other options result when
variable time intervals are considered. These sampling
schemes, which are not currently in extensive use, offer
many advantages in minimizing cost, storage, and data
requirements. The idea of proportional sampling is to
gear the sampling rate to such characteristics of the
signal as variation, amplitude, or a combination thereof.
Threshold or alarm sampling is based on the concept of
collecting and transmitting data only if the signal
monitored moves outside preset high or low boundaries.
Sequential sampling consists of sampling a parameter or
signal until some limit or condition is satisfied. The
sporadic sampling category includes much of today's
unplanned monitoring efforts.
It is our belief that the averaging time used in
acquiring and reporting environmental data should be
consistent with published standards. Except in the case
of specialized research projects, the use of averaging time
of less than one hour does not appear to be warranted
by the gain in information.
Verification
Without a proper and systematic verification
procedure, any monitoring program is without scientific
value and probably inadequate for enforcement or
administrative purposes. A satisfactory verification
system is quite complex. We will cover only a few
representative ideas here.
A standard or reference method should be
operationally defined in terms of sampling procedures,
equipment, sample handling, a laboratory testing (round
robin), published and promulgated by a regulatory
group. A need exists for a clear-cut procedure for
certification of new standards and comparison with
existing ones. A standard method should have, at least,
the following characteristics:
Utility
• Reliability
• Maintainability
• Low Cost
• Sensitivity
• Specificity
Environment parameters are given in a variety of units
(example, ppm, jiig/m3, COH/1000 linear feet) and on
ordinal, cardinal, and interval scales. If standardized
units and scales cannot be set, and if it is desirable that
they are, then standardized accurate and unambiguous
methods by converting values among those units and
scales which are employed are imperative. Some efforts
have been started to standardize units. The rate at which
these initial efforts are adopted must be accelerated and
require the support of both individual governmental
agencies and scientists engaged in research.
The previous chart (Figure 7) suggests many criteria
by which monitoring programs should be evaluated
during planning, development, and utilization phases.
Consideration of the factors shown here is essential for
effective design of monitoring systems.
DIMENSIONS REDUCTION
Because cost is often proportional to the number of
stations, the number of analyses, and/or the number of
computations, every attempt should be made in reducing
dimensions. Cost considerations are not the only reasons
why the dimension must be reduced. In order for policy
makers to reach timely and effective decisions regarding
alternative strategies, the monitoring program must be
designed and operated subject to the ultimate system
user's requirements. The size of the problem can be
reduced during data collection, measurements, analyses,
and presentations (Figure 8).
Collection
Reductions in the amount of data collected are
possible within the areal and temporal aspects of
collection. An example of an areal collection technique
which rapidly provides the minimum amount of
information required for a decision is illustrated by the
topologically optimum water-sampling plan for rivers
and streams described by W. E. Sharp. This is a
procedure that optimizes the search for sources of newly
discovered pollutants and will locate water quality
monitoring stations according to a uniform plan. The
centroid of a drainage network is located to divide the
basin into two parts of equal magnitude. Samples are
taken on both sides of the centroid and analyzed before
taking the next sample so that one-half of the network
could be rejected on the basis of the analysis. Similar
sampling occurs around the centroids of remaining
portions until the source is located.
The applicability of this technique for isolating
pollutant sources in other media should be considered in
the design of monitoring networks whose objective is
enforcement of regulations. Modifications of the
technique might be required to account for special
-------
164
CYCLING AND CONTROL OF METALS
CU VA CD
CU
XX
XX
XX
1. ACQUISITION -^ ,£-
• TOPOLOGICAUY SEQUENTIAL X\
2. MEASUREMENT
•CORRELATION/REGRESS ION
APPROACH
3. ANALYSES
• BATCH PARTITIONING APPROACH
4. PRESENTATION
•INDICATORS/INDICES
Figure 8. Dimension reduction.
segments of the monitor/pollutant/media/objective
characteristics.
Examples of temporal data collection techniques
which provide a sufficient number of samples to
estimate pollutant concentrations within preset
confidence limits are illustrated by analysis conducted
by W. F. Hunt, Jr. and by the study of D. E. Phinney
and J. E. Newman. These procedures specify the
frequency of air monitoring necessary to characterize air
pollution for a given time period and area to a given
confidence interval. Conversely, the precision associated
with preset sampling frequencies can be derived so the
effectiveness of alternative plans under anticipated
operational conditions can be examined.
Measurement
Another method of reducing the dimensionality of
data while still obtaining maximum available
information is demonstrated by employing the laten
structure of correlations matrices to infer unmeasured
pollutant concentrations. For example, based on the
knowledge of cross correlations between pollutants or
correlation with a third variable (example, population;
number of cars), it is possible by measuring one
pollutant of generally less than m to predict the
concentration of other correlated pollutants by using
such statistical methods as regression analysis.
Analysis
Various techniques exist for reducing the number of
analyses needed to confirm, for example, the presence of
a trace metal or to identify where it occurred. These
techniques can generally be classified into group-testing
methods. In these methods, analysis is made on a
composite sample formed by combining a small portion
of each sample. If a negative result is obtained, it can be
concluded that none of the samples have the pollutant
under investigation. If a positive result is obtained, then
at least one of the samples contains the pollutant. A
second analysis is then performed, usually on two
composite subsamples. The process continues until a
conclusion can be drawn for all original samples.
Modifications to the batching method involve the
number of composite subsamples formed and the
number of original samples included in the individual
composite. These modifications affect the rate at which
a conclusion can be formed for the population of all
original samples by determining the number of successive
analysis which must be performed.
Presentation
To obtain a total view of our environment we are
required, even forced, to conceive and measure a finite,
but very large number, of pollutants or residuals
associated with human activities. An equally lengthy list
would be required to characterize the natural
environment.
Reduction in the presentation dimensionality is
necessitated by the vastness of the number of pollutants
and the limited ability of the investigator to comprehend
the net effect of simultaneous changes in individual
pollutants.
Indicators have been developed in the past by
employing simple deterministic models of variable
relationships. A more powerful tactic would apply
multivariate statistical methodology, such as principal
component analysis and canonical correlation, to
effectively reduce the dimensionality of the presentation
manifold.
PURPOSE OF MONITORING SYSTEMS
If we need a taxonomy of monitoring systems, the
most meaningful appears to be according to purpose.
Three broad intents in monitoring programs are almost
exclusively and exhaustively covered by a separation in
normative, forecastive, and causative monitoring (Figure
9).
•NORMATIVE
• FORECASTING
• CAUSATIVE
CURRENT STATUS
HISTORICAL TRENDS
PREDICTION
REACTION
MECHANISMS
INTERACTION
BACKGROUND
AMBIENT
SOURCE
POINT
INTERVAL
TREND
Figure 9. Types of monitoring systems by purpose.
Normative can be redefined as descriptive. It either
describes the current status or past historical trends and
is used for background definition, ambient
environmental qualification, and source characterization.
The causative or correlative monitoring concept
attempts to reach fundamental issues involving
mechanisms, interactions, and action reactions.
Forecastive monitoring is essentially a simultaneous
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ENVIRONMENTAL FORECASTING
165
projection and prediction. This kind of monitoring is
often biological in essence using sentinel species to
provide, because of their sensitivity, an alarm before the
chemical/physical detectors can detect the effect or
presence of environmental stressors. Forecastive
monitoring can be further broken down according to the
technique into statistical (prediction), biological (alarm),
and physical/chemical (precursor).
CONCLUDING REMARKS
We would like to leave you with the following
remarks extracted from the previous discussions:
1. Raw data are not information.
2. Pollution amount is not equivalent to concentration.
We must measure both. Indeed we must learn to
measure amount, concentration, effective fraction,
size and characteristic distribution, reactivity,
accumulation, reaction, synergism, etc.
3. Pollution monitoring is a study of extremes from
source emission to epidemiological studies.
4. The ultimate environmental quality monitoring is an
effect monitor. Ideally we need a personalized,
portable, integrating, specific series of environmental
monitors.
5.The quality of environmental monitoring data is
defined by the weakest link in the total monitoring
process.
6. The greatest needs and the greater requirement for
improvement should be in concepts of monitoring as
we have tried to show here today.
BIBLIOGRAPHY
1. Arnold, J. C., A Markov Sampling Policy Applied to
Water Quality Monitoring of Streams, Biometrics
26 (4): 739-748,1970.
2. Burton, J., et al., Guidelines for the Acquisition of
Validated Air Quality Data, MRT-6000, The
MITRE Corporation, April 1971.
3. Charlson, R. J., Note on the Design and Locations of
Air Sampling Devices, JAPCA 19 (10): 802,
1969.
4. Guidelines: Air Quality Surveillance Networks, EPA
Pub No. AP-98.
5. Hunt, Jr.,W. F., The Precision Associated with the
Sampling Frequency of Log-Normally
Distributed Air Pollutant Measurements, JAPCA
22(9)687-691,1972.
6. Jenkins, D. W., Biological Monitoring of the Global
Chemical Environment, Smithsonian Institute,
Washington, D. C., June 1971.
7. Osburn, H. S., L. J. Lane, and J. F. Hundley,
Optimum Gaging of Thunderstorm Rainfall in
South Eastern Arizona, Water Res., 8 (1):
253-265,1972.
8. Overbey, J. W., and R. P. Ouellette, The Use of the
National Aerometric Data Bank for Decision
Making, M72-19, The MITRE Corporation,
October 1971.
9. Phinney, D. E., and Jo E. Newman, The Precision
Associated with the Sampling Frequencies of
Total Particulates at Indianapolis, Indiana,
JAPCA 22 (9): 692-695,1972.
10. Saltzman, Bernard E., Significance of Sampling Time
in Air Monitoring, JAPCA 20 (10): 660-665,
1970.
11. Sharp, W. E., A Topologically Optimum Water
Sampling Plan for Rivers and Streams, Water
Res.,7(6): 1641-1646,1971.
12.Yamada, V. M., Current Practices in Siting and
Physical Design of Continuous Air Monitoring
Stations, JAPCA 20 (4): 209-213,1970.
-------
SESSION V
ECONOMIC AND LEGAL ASPECTS
Chairman:
G. Strasser
Battelle's Columbus Laboratories
-------
ECONOMIC AND LEGAL ASPECTS
G. STRASSER
Battelle's Columbus Laboratories
Columbus, Ohio
I made a lisi of a few items to which I want to allude
briefly. If we look at the so-called environmental
situation today, and I avoid the term problems because
of the makeup of the audience, we look at it from
different points of view. The economists, the scientists,
the people, the consumerists, and the advocates of
consumerism, all have views of what the problems are.
Perhaps it's fair to say that fundamentally what we are
talking about when we discuss problems of the
environment is an internalization of externalized costs.
By this I mean many of our industrial products and
services that we have been producing. The process itself
has not absorbed the total cost of the activity but some
of it has been externalized, either into our social or into
our physical environment. As long as these social and
physical sinks are not saturated, but perhaps limitless,
there is no difficulty with such externalization. When
they begin to saturate, the public gets frightfully excited
about it. Then there is a drive to see just exactly how
much is permissible to be discharged into the physical or
into the social environment which creates disruption. I
think, in the opinion of many, we have reached a point
where there is too much concern about this balance. We
have a movement today of how to improve our
environment, and to a large degree this improvement will
depend on how we can reintroduce into the original
costs much of the externalized costs. This is much easier
said than done. If all of a sudden we set standards that
existed for the air or for the river 200 years ago, it is
perhaps fair to say that the majority of our industries
would be bankrupt overnight. Since much of what gets
done today gets done with a de facto understanding of
cost externalization, the real question that faces those
who are concerned with the environment is not whether
or not something has to be done about the situation. I
believe most would agree that we should do something.
The real question is twofold. How to do it? And, second,
at what rate and in what manner should it be done? In
the process we don't want to create more economic,
social, and other disruptions than the good we would do
by reversing this environmental trend. The things that
have happened and evolved during decades, if not
centuries, won't be re-written overnight. Therefore, the
real trick is how to evolve the right mechanisms, the
right legal and other ancillary processes which will allow
us, in an expeditious way or manner to correct the
situation.
There are a number of intriguing anecdotes about the
difficulties of people who have tried to right some of
these wrongs. I'm sure everybody in this audience is
familiar with the Food and Drug Administration and
with Dr. Herbert Ley who used to be its Director. I very
vividly recall a testimony that he gave about three years
ago in front of the Dario subcommittee. H said we set
standards not based on physiological consequences as we
should, but based on what our chemists, who are getting
smarter and smarter by the year, can do in terms of
detecting smaller and smaller trace elements in
everything. If this trend is allowed to continue, he said,
pretty soon we will find everything in everything and we
will not be able to eat anything. He emphasized we
should be trying to find a proper cause and effect
relationship between what we do and what its causes are;
we should differentiate between the risks that we as a
government impose upon the population, which the
population can do very little about, and the risks that
people assume on their own. In the former category
would be foodstuff that people have to eat. This is, so to
speak, the government imposed risk. On the other hand,
if you want to go skiing in the Alps, and break your leg,
that may have a greater risk involved, but that's
a personally selected risk.
During the era when there was a great deal of concern
about mercury in tuna, I was at OST. We all had our
assignments, and my neighbor got the assignment of
answering phone calls which went like this: What is OST
doing about mercury in tuna? Those of you in the
government can appreciate a flood of calls like that from
laymen. My neighbor at the office could take it only so
long. After a while he said: We bind up all the tuna and
are in the business of making thermometers. The job to
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answer tuna questions was reassigned to someone else
the following day.
As you can see, many things are happening in trying to
make this transition. I could rattle off a number of other
things of which you are most familiar, such as the
National Environmental Policy Act of 1969. I'm sure
there is not a single individual in this room who doesn't
know about this and about the Environmental Impact
Analyses and the Environmental Impact Statement.
Some say it is a new thing. Others asked what else is new
under the sun? We have been doing some of this before.
To what extent either of these statements is true I'm not
prepared to say. Some of you probably know about a
new law that was signed by the President two weeks ago
- the Technology Assessment Act of 1972. This
Technology Assessment Act is very intriguing because
there are a great many commonalities — the subjects
overlap almost 90 percent the concerns of the National
Environmental Policy Act of 1969.
Just out of sheer conincidence I cam across something
which I would like to share with you. It is an act, and I
quote slightly paraphrased, which says every industrial
plant shall use the best practicable means of preventing
the discharge into the atmosphere of noxious gases and
other noxious effluents arising -from their work or of
rendering such effluents harmless when discharged.
Which of our two acts do you think this comes from?
I'm not asking for an answer. I want to tell you that this
is an English act, dated 1863, and the Preamble is
slightly paraphrased. An act for the more effectual
disposal of industrial wastes. Where it is expedient to
provide for the better disposal of industrial wastes, be it
enacted by the Queen's most excellent majesty, by and
with the advice and consent of the lords, spiritual and
temporal and common in the present Parliament
assembled, and by the authority of the same that
follows. The point I'm trying to make is that a lot of
people have been grappling with problems like this, and
nothing is new under the sun. The big difference
between what has happened in the past and what is
happening now is that we have saturated these things
more than we saturated them in the past, and the
leverage that technology permits us to exercise is much
greater than it was in Queen Victoria's time. Therefore,
if we do some good it could be much more than what we
could do in the olden days. But if we foul up something,
we can do a much better job of that too. So it's sort of
important to try to do something about it in a
systematic way without bankrupting ourselves in the
process. This leads me to say that in doing all this I think
it's imperative that the technical people and the
engineers, who are so concerned with numbers and
close-form solutions, whenever possible quote close-form
second order, partial differential equations and
operations research.
I'd be the last one to knock these subjects, because
I've been making my living at them for a long time. But
it's clear that other considerations have to enter into our
deliberations. Nowadays things are not as easily
modelable or simulatable as they have been. You really
have to see new institutional frameworks and ways in
which we can come to grips with the problems facing us,
even though the roots of many of them date back to
1863 or before. In my opinion it would be nice if
technical people would get a better perspective about
the historical, legal, traditional, and other constraints
within which these problems can be solved. And just to
show that I don't discriminate against the technical
people, I would also dearly like to have social scientists
be made to take courses like calculus appreciation. Then
the discussion of multidisciplinary problems, a first and
second derivitive, and saturation curves and expedentials
wouldn't come to them like the rediscovery of the
wheel. There are a lot of things that we can do as we
approach these problems in an interdisciplinary fashion.
We must bring the practitioners up to speed by giving
them some contacts and background that they lack due
to the kind of education they receive. This background
is imperative if they are to work jointly in a constructive
manner.
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THE SOCIAL IMPLICATION OF CONTROLS
P. MICKEY
Concern, Inc.
Washington, D. C.
May I begin by reading you a quote of Blackstone's
which is said to have influenced the thinking of
Alexander Hamilton in the Declaration of Independence
and the U. S. Constitution.*
The principal aim of society is to protect individuals in
the enjoyment of those absolute rights which were
vested in them by the immutable laws of nature; but
which could not be preserved, in peace, without that
mutual assistance and intercourse, which is gained by
the institution of friendly and social communities.
Hence it follows, that the first and primary end of
human laws is to maintain and regulate these absolute
rights of individuals.
Individual or group awareness of the rights of citizens
to the enjoyment of living or the quality of life and the
part that communities must take in assuring these rights
to all is the basic philosophy of today's environmental
groups.
We no longer live in a simple world where clean air,
clean water, and uncrowded land can be taken for
granted. The problems of an over-populated world need
the cooperation of all of us — government, industry, and
citizens. Each problem begins somewhere. That
somewhere is usually directly traceable to the fact that
there are more people needing more jobs to earn more
money so that they can consume more and ultimately
throw away more. This has become a natural, normal
way of life for most of us. But maybe there has to be an
end to the kind of consuming we have been doing, and
this kind of growth in our communities. What might
have been considered progress and prosperity a few years
ago can today be recognized as degradation and a
misplacement of values.
Industry tells us that consumers demand many items:
high phosphate detergents for whiter clothes; throwaway
bottles and cans; fancy packaging; lighter throwaway
plastic containers, and many more. But in truth it is
*William H. Marvell, Man-Made Morals: Four Philosophies That
Shaped America.
industry which has spoiled us by producing these and
other products, and convincing us that we need them
through Madison Avenue ads. However, there is a
growing interest and awareness on the part of the buyer
today of the problems that are a result of this
convenient living and overindulgence. We, at Concern,
believe that we may be seeing the beginning of a buyer
revolution where concerned citizens are looking for a
new market for products created with an awareness of
environmental impact. We have dealt with this new
market in our publications called Eco-Tips.
We have also tried to encourage re-use and recycling
for two reasons: to reduce solid waste and to help
preserve our resources. Instead of being consumers, we
must really become users and re-users if we are to
protect the world around us for future users. A well
known, or well-quoted, statistic is that although the
United States represents less than 6 percent of the
world's total population, we consume hah0 of the world's
natural resources (each year). I am not an economist,
nor are most of the consumers whom I represent, but it
really doesn't take an economist to realize that there is a
limit to production and consumption which can be called
progress. If we use up our resources without trying to
find ways to re-use or recover them, we may find our-
selves and our children running out of world in which
to live.
As a first, and perhaps a small, step, we at Concern
have joined with many interested citizens in trying to
encourage recycling of paper, glass, and aluminum
through the formation of recycling centers. In almost
every city of any size in the country today you will find
housewives lugging their recyclable items to one of these
centers. This is not the long-term answer. But if there is
a real effort on the part of citizens to return some of our
resources for recycling, there will be more of an effort
on the part of industry and government to work out a
better solution for overall long-term resource recovery.
There is evidence of industry effort. For instance, in
the aluminum industry 10 cents a pound brought back
almost a billion cans in 1971 and may bring back more
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than a billion and a half in 1972. This is a small
percentage - about 12 percent in 1971 of the total
aluminum cans which could be recycled. But when you
think that the percentage has risen from 0 percent to 12
percent in the past few years, the increase is at least
encouraging. And although the money involved is
perhaps the prime motivation, we feel that this increase
in reclamation is dependent to a large degree on citizen
interest.
Because of the difference in the value of the resources
used in both glass and paper, recovery on an economic
basis does not show the same promise as aluminum. But
in spite of this, both industries are recycling on a larger
scale than ever before. And in both instances the desire
of citizens to cooperate has sparked a greater industry
effort.
If it's true, as a spokesman for Reynolds has stated,
that large amounts of aluminum have been recovered,
and even larger amounts expected to be recovered
because of the 10 cents a pound reward, why, then, is
there skepticism about whether consumers will return
bottles and cans to recover a five cent deposit. If
consumers demand the convenience of throwaway
containers as industry has repeatedly told us, then not
even the aluminum drive will succeed. We believe,
however, that citizens today have two basic motives
prompting their behavior: Both environmental and
economic.
It may take 10 to 20 years, maybe longer, to fully
apply the technology available for separation before
disposal, thereby reclaiming a much larger proportion of
our valuable metals and other resources. But with
interim measures involving citizen awareness of the
necessity for resource recovery, there will be more of an
educated interest in improved solid waste disposal
systems which are not dependent on the volunteer
efforts of consumers.
Part of our job, as we see it, is to encourage people to
think more, use less, re-use whenever possible, and handle
the remainder with the least hazard to the environment.
We have not actively advocated government controls.
However, we have certainly suggested that individuals or
groups control and rethink their consumer appetites in
many areas. We have done this only after long months of
study and conferences with government and industry
scientists well-known in each field, and other highly
credible private and environmental groups. The most
important part of our work is the education of the many
thousands of people throughout the country who have
written us because they want to know what they can do,
how they can do it, and why.
We knew that detergents with a very high percentage
of phosphates were the biggest selling detergents, and we
knew that these detergents probably produced the
whitest wash. However, we felt convinced that women in
many parts of the country would respond favorably to
the suggestion that they switch to a low phosphate
detergent or soap if they were made aware of the
concern of limnologists in and out of government for the
premature aging of many bodies of water in our country
and the part phosphorous was playing in this
eutrification. Sales of high phosphate detergents
probably did not go down, but the voice of the
consumer was heard. Local legislation was enacted in
several areas, and industry reacted with a reduction in
phosphates. The recent announcement of Proctor &
Gamble of a reduction to six percent phosphorous
makes the response of the big three in the detergent
industry unanimous. Perhaps for a long-term solution, a
substitute which is neither harmful to the environment,
nor to humans, will be found because of consumer
interest and government and industry research.
In the plastics area, we have tried to inform the
consumer of the solid waste disposal problems of pvc
containers. We have also been concerned about the
recycling capabilities of plastics. Because of the action of
many consumer groups, such as ours, and the concern of
the government, especially EJP.A., industry has
responded with a search for substitutes and a continued
search for the recycling possibilities of all plastics.
While we all realize that some pesticides are sometimes
necessary, we have tired to steer the housewife and the
gardener toward other, safer methods of pest
control, using the less harmful pesticides only when
absolutely necessary. We have done this both through
our Eco-Tips and our calendar called The Living Garden
which we co-sponsored with the Audubon Naturalist
Society. This calendar makes suggestions month by
month on how to garden without dangerous pesticides
and sells well throughout the country.
We have also tried to encourage the use of returnable
bottles. Judging from the state and local legislation,
either pending or enacted, we are not alone in believing
that a container that is returned for re-use or recycling is
the only environmentally sound container.
In the larger cities, particularly on both coasts, it is
not surprising that community groups and
environmental groups are not willing to sit quietly by
while inversions trap pollutants from automobiles and
citizens are warned that outdoors is off limits to them.
The Clean Air Act of 1970 became a law because of the
pressure of social groups on Congress. The controls
spelled out in this law for Detroit to meet by 1975 and
1976 are tough controls, and may have profound
economic ramifications, but I can't believe there is
anyone, even in Detroit, who doesn't realize that the
mounting air pollution from automobiles is a real
problem and one that must be solved. Aside from the
tremendous job EJP.A. has to face in this exigency,
community groups must also become involved. Lay
citizens are not capable of suggesting alternatives to the
internal combustion engine, or the type of catalyst to be
used as an anti-pollution device, or how many parts per
million of carbon monoxide or nitrogen oxide should be
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171
allowable in the air they breathe, but the same citizens
must become more aware and better educated to the
problem so that they can understand how to help
implement the solutions as they come along. Concern
has tried to make suggestions to the citizens on its
mailing list. Because of the potential health hazards of
lead, we have suggested the use of the lowest lead,
lowest octane gas that can be used without an engine
knock. We have urged the use of unleaded gas whenever
possible and tried to explain why. We have been told
that many people are having the anti-pollution devices
which are now being installed on cars removed because
their cars use more gas and do not run as smoothly. This
attitude can best be discouraged by an understanding of
the problems of automobile pollution.
Our next publication, which we expect to have ready
to mail in January, will be devoted to energy. We will try
to help consumers realize the need for a change in
attitude toward a more intelligent and efficient use of
energy. All energy costs will go up in the future. We
hope this rise in price will cause people to rethink their
energy needs. Large amounts of energy can be saved
without any real sacrifice. To this end we will make
suggestions for energy conservation in the fields of
transportation, architectural design, home heating and
cooling, household appliances, and commercial waste. As
far as recycled materials are concerned, we will try to
encourage an expansion of the market. There are, and
will be, many inconveniences (and expenses) for all of us
if we are to clean up our environment. But if
government and industry, and research institutions such
as Batelle, Midwest Research, and others will work
together to try to find answers, it is necessary for citizen
groups such as ours to become better educated and to
encourage the active cooperation of individuals and
communities.
Realizing that teamwork is necessary in order to
accomplish environmental and social goals, we might
think of this teamwork in terms of a football game. The
citizen team has long been missing from the football
field. We have had industry teams playing, government
referees, and citizens sitting in the stands screaming
about the calls. These citizens should either be on the
field, or lose their right to scream about the calls. We are
beginning to see more today of the citizens coming out
of the stands and getting onto the playing field.
No one would argue that the road toward ultimate
solutions is a long one. I don't think any one would
argue that this would be a much longer road without
community involvement. We, as dedicated
environmentalists, undoubtedly will stumble a little
along the way to finding the long-term answers we are
seeking. We feel an urgency to find well-thought out
"Now" answers until technology is available for the
long-term solutions. But there must be steps taken now
by all of us, whether they be individual steps such as
careful, selective buying, intelligent use and re-use, and
thoughtful disposal, or group steps, such as an active
interest in local legislation for pollution control and
bond issues to support new technological advances for
water treatment or solid waste disposal systems.
The worst thing that could happen for all of us, and
our children, is to try to live with problems that vitally
affect us, rather than trying to work together to do
something about them.
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HOW MUCH RECYCLING IS ENOUGH?
T. PAGE*
Resources for the Future, Inc.
Washington, D.C.
INTRODUCTION
When people think of spaceship earth, they generally
think of a closed economic system. Except for solar
energy, in the long run all the flows are recycled. The
idea is attractive because it implies a kind of social
immortality. Until the far-off day when something
happens to the sun, there is no reason why human
existence cannot go on generation after generation.
Actual spaceships are not immortal, of course. Apollo's
life-span was considerably less than a month; and from
the first day vital stocks were depleted while satellites of
garbage began to accumulate around the spaceship.
There is some irony in the fact that the economies of
primitive tribes approximated the concept of spaceship
earth far more closely than the actual spaceship Apollo.
And modern economies seem to be moving away from
the conditions of spaceship earth to those of spaceship
Apollo.
A simple structure of economic flows is illustrated in
Figure 1. For a long-run steady state, flows to and from
each sector must be equal. In a primitive economy the
extractive flow G is small, hence the waste flows A and
B, and there is little to distinguish environmental dumps
from environmental sources. Natural processes (C)
quickly transform economic wastes A and B to their
pre-use forms. But in a modern economy natural
recycling cannot keep up with the production and
discard of DDT, radioactive waste, fossil fuel
combustion, packaging residuals, and the like. Not only
cannot natural processes keep up with the increase in
waste flows, but also the form of waste residuals is
becoming less amenable to environmental processing.
Flow C lags behind A and B and also extraction G.f
Modern economies are suffering from the twin
problems of too much waste and too few raw materials.
'Research Associate at Resources for the Future, Inc.,
Washington, D. C. The views expressed are his own and not
necessarily those of REF.
fThe dashed line is the boundary between the man-controlled
and priced economy and the uncontrolled and unpriced
environment.
£ "Mines" includes land for agriculture and forests.
AIR POLLUTION
WATER POLLUTION
SOLID WASTES
Figure 1. Simple schematic of environmental
economic flows.
Greater recycling (more of C, D, E, and F) is often
suggested as a solution to both problems. The question is
how much recycling is just the right amount. A purist
might be tempted to answer everything. But then are we
to stop burning fossil fuel while waiting for new coal to
form, and are we to stop using paint because its use is
dissipative? A sophisticated version of spaceship earth is
not to require that all sector flows be brought into
balance, but only the costs of maintaining flows. Instead
of closing down copper mines, in this version technology
would be channeled and simulated sufficiently to offset
the tendency toward rising costs as the better grade ores
are depleted. Instead of a long-run steady state in flows,
the sophisticated version recognizes that to achieve
social immortality it is sufficient to maintain forever
constant costs for service flows. At the opposite extreme
of the purist (C = G) is the economist who might counsel
us not to take any active policy toward recycling at all:
Simply work to improve markets and then let the
markets decide how much material of each type gets
recycled.
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EFFICIENCY POINT OF VIEW ON RECYCLING
When an economist recommends the improvement of
markets, he generally has a standard of market
perfection in his mind. With perfect markets there are no
monopolies; each firm is too small to influence market
prices. Everyone is perfectly informed about market
opportunities and product characteristics. Market
transactions, as well as information, are costless. And,
most important for us, all external costs are internalized.
When a firm purchases labor inputs, the cost of labor is
internal to the firm. But a firm's smoke emission is a
cost as well, as it imposes burdens on those who receive
it. If there is no smoke control, smoke emission is a cost
external to the firm, and the incidence of cost falls
outside the firm. If the firm pays for the smoke, by
effluent taxes based on the damage to downwind
receivers and by undertaking costly abatement activity,
then the external cost of smoke emission is internalized.
There is an important theorem in economic theory
which tells us that under the above conditions of market
perfection the economy is welfare efficient. That is,
there would be no way to rearrange economic inputs and
production and distribution activities to make anyone in
the present market better off without simultaneously
making someone else worse off. It is difficult to see why
society should be content with an inefficient economic
allocation in which the lot of some can be improved
without hurting others. In order to move closer to
efficiency, certainly a desirable property, economists
recommend steps that move us toward the conditions of
perfect markets.
While recycling is not viewed as desirable in itself,
steps toward the conditions of market perfection would
increase the amount of recycling. In order to internalize
costs, effluent fees or standards must be imposed upon
the emission of air and water pollutants and disposal of
solid waste. We can imagine toll booths set up on paths
A and B with charges on the flows on the basis of
downstream damage. The effects are obvious: Because of
the increased cost of disposal, byproduct recovery
becomes more economically attractive; instead of paying
a penny a pound, say, to discard old newspapers,
households would find the alternative of accumulating
and recycling more attractive; in order to put off the
final disposal fee, cars and other products would be
designed for greater durability; products would become
less material intensive (transistor over vacuum tube
radios); and services would be favored over products,
relative to the present situation. Flows D, E, and F
would increase relative to A and B.
Since mining involves large external costs (acid mine
drainage, tailings, etc., which we can visualize as flowing
through B), internalization of costs would also favor
recycling relative to G as well. However, some recycling
activities are notoriously polluting so that internalization
of costs would not encourage all forms of recycling.
It is easy to exaggerate the price changes caused by
internalization of costs. Certainly internalization of costs
will not drive us back to the 18 century, as some
alarmists maintain. Economic theory strongly suggests
that internalization of costs will substantially increase
social well-being, not all of which is measured by GNP.
Jerry Delson estimated that price increases in the
coal-electric industry caused by internalization of costs
would be in the range of 10 to 15 percent. (RFF study
in process.)
From the point of view of economic efficiency,
market perfection is important, not recycling per se, or
durability, recoverability, or less material and energy
intensive products. Whatever level of recycling that
occured under perfect markets would be the right level.
While the recommendation to internalize costs goes back
to Pigou in the first part of the century, it is only
recently that the recommendation has been put into
practice. As the use of regulations, standards, and
effluent fees becomes more widespread, we expect an
increase in recycling and other forms of material and
energy conservation. At the same time that extractive
industries find themselves paying more of their external
costs, the external costs themselves have been increasing.
As we move from one percent to one-half percent
copper ore the amount of solid waste to be disposed of
doubles. And finally there is some evidence that the
century-long trend of constant private costs of mineral
extraction is changing toward increasing private costs.
These three factors affecting resource extraction, an
increasing fraction of external costs to be internalized,
greater external costs, and growing private costs, all
stimulate resource conservation (choke off G in favor of
more D, E, and F).
As an economist I regret the last two factors which, if
true, will diminish present and future welfare and show
that we are beginning to lose the Malthusian race
between diminishing returns to nature and technology;
but I applaud the first factor which will increase our
aggregate well-being though probably not the short run
well-being of the mineral extractive industries.
MARKETS, EFFICIENCY, AND DEPLETION
Thus far the point of view of efficiency and perfect
markets has had nothing to say about the second of our
twin problems, that we are depleting our vital stocks of
raw materials. When we use up tin and phosphates today
and scatter them beyond reclamation, we pre-empt their
use tomorrow. Foreclosure of the future's opportunity is
a cost imposed upon the future, just as is bequeathing to
the future high levels of mercury in ocean fish. Is
depletion of tomorrow's resources an external cost in
exactly the same way that unregulated pollution in the
present is an external cost?
The answer is no. Individual firms have an incentive to
take into account the costs of depletion imposed upon
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175
the future while there is no corresponding incentive, in
the absence of regulation, disposal fees, or government
specifications, to take into account the external costs of
pollution in the present. If the owner of a mineral
deposit believes that the future price is going to be bid
up in response to the mineral's depletion and hence
future scarcity, then the owner has an incentive to
stretch out production. In the past incentive, while of
great interest to economists, was probably very weak.
Technology kept pace with Malthus, and with constant
costs the speculative value of reservation was worthless.
In addition, many deposits are in politically unstable
areas overseas so that there is a powerful offsetting
incentive to get it out before nationalization. Now,
however, if the price trend is upward, for scarcity
reasons, there may be more resource reservation due to
speculation on future price increases. The point is that
there is an asymmetry in ownership of material in the
environment. In the environment at the top of the
diagram, valuable materials are owned or are managed by
profit-seeking firms. But in the environment at the
bottom burdensome materials, pollutants, are disowned
by these same firms, by means of smokestacks and
outflow pipes.
So the twin problems of depletion and waste
accumulation are not twin after all. The market fails
where ownership fails. And by this standard many
economists have taken ownership failure as a cue to
advocate artificial markets of effluent fees and standards
for wastes entering the environment, and the existence
of ownership of resources as a cue to let the market
decide how to allocate resource extraction over time.
Now let us suppose for a minute that somehow
artificial markets have been created which effectively
internalize the costs of waste disposal and the other
conditions for perfect markets are more or less met. Is
the market going to give the future a fair shake with
respect to inter-temporal allocation of virgin resources?
Is the market going to encourage us to gobble up the
nonrenewable resources of this generation and leave
scattered and contaminated residuals for the future to
recycle as best it can? Perhaps it is fair for us to exploit
the best deposits and leave the future with the remnants,
for the future will be smarter, having better technology,
and richer, at least in terms of GNP. Many will think it
unfair.
In order to tell whether or not individual firms are
motivated to practice sufficient resource reservation, we
need a criterion to make the necessary comparisons
between present and future well-being. Harold Hotelling,
who developed the "theory of resource reservation,"
advocated along with many other economists a social
criterion analogous to a firm's profit criterion. For each
generation there should be defined a measure of
well-being (welfare function), depending on individual
preferences and market fulfillment of the preferences.
Hotelling assumed that just as a firm is best off when it
maximizes the present value of its profit stream, society
is best off when it maximizes the discounted sum of
social welfare measures. The criterion Hotelling
proposed is an economics of the firm writ large. We will
call it a present value welfare criterion (PVWC).
Many people find the discounting of future welfare
repulsive because it seems to favor the present over the
future. However, the PVWC is not inherently biased
toward the present. If we are going to combine measures
of welfare over time by addition, we have to discount
the future to offset productivity in order to keep the
future from being favored over the present. Suppose we
took the PVWC with a zero discount rate: Instead of the
present consuming a bushel of corn the criterion would
instruct us to plant the corn so that the future could
have two bushels. Furthermore there is a market
tendency for a rate of discount to be equal to the
productivity of capital; this in turn tends to equalize
social welfare over time.
One reason for the popularity of the PVWC among
economists is that it is a normative statement of what
markets tend, more or less, to do by themselves.
However, while the PVWC is not guilty of inherent bias
toward the present, it does have a number of drawbacks.
Perfect markets is an attractive objective
intra-temporally because it leads to welfare efficiency
for those in the present market. But perfect markets,
which are somehow lined to the PVWC, do not
guarantee welfare efficiency over the larger set of
present and future people. In a market equilibrium the
present is indiffernt between a little more investment
and a little more consumption, but the future prefers
more past investment to more past consumption. This
non-matching of indifferences lays the basis for gains
from trade, if trade were possible between generations.
And the possibility of gains from trade means that the
present equilibrium was not welfare efficient after all.
Linkage between present and future is a mechanism by
which the future can influence the welfare of the
present. For example, our present efforts at species
preservation or wilderness preservation are more valuable
to us if we believe that the next generation will increase
its efforts at preservation. Diversity of species is an asset
whose value continues over many generations. Our
efforts at species preservation are not just for our
generation, or the next, but for many generations. Thus
our valuations of our efforts of preservation depend on
our beliefs about future actions. Since all the traders,
present and future, cannot bargain in a single room,
there is no way for present markets to take into account
these asset linkages. Consequently the market will
provide too few of these assets whose value is linked
over time. By the same argument the market will provide
too many negatively valued assets whose disservices are
linked over time.
On the other extreme from thinking that the PVWC
inherently biases welfare toward the present, it is
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sometimes said that the PVWC, working through perfect
markets, would maximize future welfare. The PVWC can
only maximize one thing at a time, and the maximand is
a sum of geometrically weighted welfare measures and
not the welfare of any single period. The PVWC does not
guarantee that future welfare will be as large as our own
or even that enough resources wil be provided to sustain
future existence.
Nor does the PVWC guarantee that allocations made
by the present market are ones that we will be happy to
live with tomorrow. It would be desirable to have a
criterion which would allocate resources in such a way
that if the next generation could change past allocation
it would still keep the past as it was. The property of
harmony is analogous to a regret-free life of an
individual. "If I had a chance to live my life over I
wouldn't change a single thing." The PVWC does not
have the property of inter-temporal harmony.
In my judgment the prescription, "perfect the
markets and let the markets decide" is distinctly less
attractive in the inter-temporal case than in the
intra-temporal case. In the intra-temporal case perfect
markets would at least provide welfare efficiency. Not
only that, but in the intra-temporal case efficiency can
be separated from the problem of distribution of wealth.
That is, for any given distribution of wealth market
perfection leads to efficiency for those in the present
market. We can, and do, alter the distribution of income
and wealth through income taxes, while we
independently recommend policy for market perfection
by effluent taxes. But in the inter-temporal case it is
impossible to separate the inter-temporal distribution of
wealth from inter-temporal market allocations. Market
allocations determine the distribution of aggregate
wealth over generations. Because in the latter case
efficiency cannot be separated from distribution, the
PVWC is not so ethically neutral as the prescription for
market perfection by internalizing enternal costs falling
on the present.
Long-lived pollutants, such as radioactive wastes,
DDT, and some heavy metals snare the same ethical
problem as conservation. We can think of these
pollutants as negatively valued capital assets which give
off streams of disservices as they depreciate. Many of
these pollutants pose problems because their effects are
unknown and we lose control of them once they get
outside the economic sector. Emitted in very small
concentrations they may accumulate in unforeseen ways
to become highly toxic, or persist as backgrounds slowly
raising the probability of cancer and other diseases.
Because these materials are sometimes very difficult to
control once generated, the best control may sometimes
be limitation of the generation. For example, cadmium
is produced with every pound of zinc. Even processed
zinc carries some cadmium with it, which gradually
wears off into the environment. One way to control
cadmium would be to recycle more zinc and mine less
new zinc. That way less new cadmium would be
introduced into the economic sector and ultimately less
to the environment affecting man. Often, however,
direct or indirect recycling will not be the answer to
control of long-term hazardous materials. Control at the
source and reduction of the source may sometimes be
the best management of a toxic material.
As we saw, the perfect market prescription of effluent
fees and standards said nothing directly about recycling,
yet imposition of effluent taxes and standards would
lead to more recycling. In the same way perfect markets
say nothing directly about recycling, yet perfect markets
with resource reservation due to speculation on future
price increases should in theory lead to resource
conservation. The point of view of efficiency treats the
two problems of waste accumulation and depletion
similarly; that is, as indirect effects rather than desirable
goals per se. But, as mentioned, while the efficiency
point of view is sufficient for the intra-temporal problem
(pollution and waste accumulation) it is less satisfactory
for the inter-temporal problem (inter-generational
transfers of wealth from depletion and slow decaying
pollutants). We may also wonder how effective is the
market mechanism of resource reservation. Suppose a
mining company can borrow or lend at eight to 10
percent but that it acts on an internal rate of discount at
18 to 22 percent. There is some evidence that such
imperfections in the capital market are widespread. How
much resource reservation will this company practice?
Not much.
WHAT ABOUT SPACESHIP EARTH?
The point of view of efficiency and perfect markets
has little to say about the future's right to existence. By
the PVWC the future's right is a collection of desires
which should be translated into willingnesses to pay and
discounted to the present. This seems to be the wisdom
of the PVWC. Yet we may ask who chose this criterion?
It seems quite possible that if there were a vote between
the PVWC and a criterion guaranteeing some form of
social immortality, the latter would win. People tolerate
many forms of market imperfection, monopolies and
misleading advertizing, for example, but they make great
sacrifices for their children and genetic lines.
Now let us assume that some form of social
immortality is considered just and desirable. With this
goal the cost of maintaining our present standard of
living should not greatly increase, and perferably should
decline, and the hazards of global catastrophe should in
some sense be minimized. Then what should we do now,
in the present? It seems clear that we should try to
estimate various possible futures which result from
present policy choices. We then choose those policy
choices which lead to desirable future states. The
procedure is a common one for macro-economic
problems such as inflation and unemployment. For
example, we decide that a six percent inflation is
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unacceptable, but a three percent inflation is acceptable.
The goal seeming right and feasible, the money supply is
then manipulated to achieve it.
One obvious policy instrument to move the economy
toward a steady state of social immortality is the
severance tax. Long-run population policies are perhaps
even more crucial than material flow policies. The two
policy areas are similar in that, for both, very gentle
incentives can have enormous effect over a 200 to 300
year time horizon. A severance tax leads us toward
spaceship earth in several ways. It raises the price of
virgin material relative to secondary and hence
encourages recycling. More important, in the longer run
it stimuates technology to develop production processes
that further take advantage of the relatively cheaper
recycled materials. And of course severance taxes, in the
long run, favor product durability and service intensive
commodities over material intensive ones.
Severance taxes are like import tariffs in that they are
collected at a small number of entry ports. They are far
easier to collect than disposal taxes levied upon the final
owner of a material. As states with anti-litter laws have
found out, it is impossible to prevent surreptitious
dumping. Schemes to collect disposal taxes at the last
manufacturer have to provide for recycled content. And
then definition and certification of recycled becomes a
difficult problem, while the problem of surreptitious
dumping remains with processors before the final
manufacturer. Administrative costs of collecting a
disposal tax are much higher at the final consumer (A)
than at the first processor (G). It may be that the best
place to collect a disposal tax is at G where it becomes a
severance tax. To resolve the question one must weigh
the reduction in administrative cost against the loss of
efficiency from collecting the disposal tax too early.
Severance taxes are understandably unpleasant to
mining companies, while they are something of a pipe
dream to recycling companies. How can severance taxes
come into being, one may ask, while depletion
allowances, which are negative severance taxes, are so
well entrenched? Yet in the near future people may take
a harsher view toward tax policy which encourages
depletion and helps transform spaceship earth into
spaceship Apollo.
It is perhaps misleading to talk about specific
resources as immutably nonrenewable with dates upon
which each will run out. Perhaps the entire planet should
be viewed as a single asset which managed in one way is
renewable and managed in another way is nonrenewable.
Economic theory tells us that even perfect present
markets will provide us with too little of the time-linked
renewable asset. The point is that the earth is an asset
whose type can be changed; we have a choice as to
which type of asset we want it to become. A hundred
years from now the choice may no longer exist. We may
have irrevocably transformed spaceship earth into a
progressively more hazardous and time-limited spaceship
Apollo.
HOW MUCH RECYCLING IS ENOUGH?
In terms of the first problem, the intra-generational
one of waste accumulation, the proper amount of
recycling is whatever amount that is induced by
internalization of costs. In terms of the second problem,
depletion and inter-generational transfers of wealth, it is
much more difficult to ansser. A minimum which might
appeal to many people is to provide enough incentives
for recycling so that we do not foreclose the
opportunity of a comfortable spaceship earth a hundred
years from now.
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LAW AND TRACE METALS
E. F. MURPHY
Ohio State University
Columbus, Ohio
INTRODUCTION
I have been asked to say a few words on the legal
problems of trace metals. It has been a problem both in
health and law for a long time; and, obviously, the
discovery of the health effects had to precede any
concern at law. Until the relationship between the
presence of some particular metal within a product or
process and a resultant disease has been established,
there is no need for the attention of the law, or, at any
rate until the advent of technology assessment concepts.
This has been the prevailing view (1).
Confining myself to metals rather than embracing
the larger aspect of trace elements, the presence of these
has served many functions over the centuries and only
slowly has there emerged any realization of
hygienico-legal difficulties. I do not suggest that the
difficulties of dealing with the entirety of the effects of
all trace elements are generically different from the
narrower issue of trace metals; but I do believe that how
to cope with nitrates and the possibility of nitrate
poisoning, carbon dioxide and the risk of the greenhouse
effect, or industrial gases and solar irradiation in the
atomsphere are far more major difficulties than any
raised by trace metals (2). Hence my narrower scope.
The metals with which I am going to deal are lead,
mercury, copper, zinc, beryllium, chrome,, iron,
cadmium, vanadium, nickel, and, while commonly not a
metal, asbestos (3). Some of their side effects have long
been known but only in recent ages have their dangers
been commonly recognized. For example, the ancient
Romans, lacking distilled alcohol, added lead salts to
their wine in order to enjoy the resulting intoxication
(4). Some attribute the fall of the Empire to the
destruction of the intellectual capacity of the elite due
to lead poisoning. During the Renaissance mercury was
liberally used as a cure for venereal disease, with little
regard for its less beneficent effects, and lead was
employed by such beauties as Lucrezia Borgia for the
dead-white face then so much admired (5). Copperous
waters were considered healthful and were widely
prescribed; and only recently have there been strong
arguments against the popularity of "deliciously tasting"
water heavy in iron. What was sought by one age has
become a condition to be avoided by another. This is
not to say that we are not right to seek such avoidance.
It is only to observe that one could expect little
prohibitory or corrective activity from the law as long as
the above practices were common.
Furthermore, we have to recognize that ever more
common economic activities have introduced into the
receiving elements of air, water, and soil quantities of
trace metals previously unknown on any except very
territorially restricted scales. For example, a recent
survey of earthworms near highways was conducted by
the United States Fish and Wildlife Service (6). It was
determined that levels of lead, zinc, nickel, and cadmium
were sufficiently high to be fatal to birds consuming
them, Zinc is in car oil and was found at all distances
measured (maximum from the highway was 160 feet).
At 50 ppm, zinc has been fatal to young pigs, but the
lowest reading for the earthworms was 52.7 ppm. Lead
is used in gasoline and was found in earthworms taken
10 feet from the highway to be 200 ppm, which is
enough to kill mallard ducks eating such worms.
Cadmium is emitted from tires and, while lethal to rats
at 62 ppm, the heaviest concentration was 12.6 only.
Nickel is used in oil and gasoline and was heaviest near
the highway. In several instances, concentrations away
from the highway were heavier than near it, which was
explained as the result of water runoff. Clearly, the
study revealed that the concentration of the auto on the
modern highway introduces factors into the ecumene
different than any known before and does so in a
manner likely to have serious impact upon the ecology.
This example does not directly affect human health, but
similar illustrations with such a result could be found
easily.
As a lawyer interested in the subject of trace metals, I
have to point out that the interest divides between
workmen's compensation law and the larger (and more
hard to determine) law of general health and ecological
effects. Both have been a long-standing interest of the
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law. As early as the 1880's, insurance to protect workers
against the ill effects of their work was established in a
few Continental countries and was urged by reformers
(7). The common law in Anglo-American countries gave
the worker no protection, in the absence of gross
negligence by his employer, and gross negligence rarely
was present within the customs of the time. The result
was that, even though reformers began to push for
statutes setting the conditions of work and ventilation in
factories in England and the United States in the 1860's
to protect the workers against bad air conditions (8), the
laws to compensate workers for disease coming from
those poor conditions did not begin to appear until the
turn of the present century (9). As to generally
atmospheric regulation, England set up an alkaline
inspectorate in the mid-1870's; but it was not until the
1960's that either England or the United States came to
have even somewhat effective air pollution control laws
(10).
All of this, however, is history. Today there exist both
federal and state laws on industrial hygiene, workers
health and safety, workmen's compensation, and air and
water pollution control that, directly or indirectly, are
profoundly concerned with the consequences of trace
metals in the environment as the result of economic
activity (11). Some of them are of recent enactment,
particularly at the federal level, and others are
sufficiently old to have accumulated a large body of case
law. But there is now enough to be able to select out
pertinent materials relating to the subject, so that one
can talk about both the problem and the law's
attempted solution of it. Because of the nature of this
paper, I shall use a distinction by the individual trace
metals rather than by legal concepts in dealing with
them. Beyond this, I have only my above caveat that the
statutes and cases divide into the larger categories of
concern with in-plant happenings and with effects upon
the larger environment.
LEAD
The oldest metal for which serious side effects are
known is lead. "Painter's colic" is a very old idiom and
the law has dealt with it in the form of workmen's
compensation awards since the establishment of that
system of legal redress. The cases involving impairment
of earning capacity, the aggravation of the disease, the
size of the award, and so forth are numerous (12). 1 shall
not discuss this aspect of the problem here but I shall,
instead, move to considering the current public fears
about lead: Namely lead-based paint and lead and lead
alkyls in gasoline.
The use of lead in house paints has been regarded as a
menace for the reason that its presence imparts a sweet
taste to the paint flakes, which induces children to eat
them. Examinations of slum children have shown large
enough quantities of lead within their systems to
adversely affect their intelligence or else to provide a
dangerous situation if a prolonged fever should cause the
body to attempt a mobilization of its resources. The
result would be a drawing out of the stored up lead in
one sudden rush (13).
Some have argued that this is an exaggeration. Not,
they say, that lead is not a serious problem within inner
city regions, but that banning it from house paint will
solve no problems and will simply remove an effective,
cheap fabric preserver of property from public
availability. A recent study in the not-very urbanized
city of Durham, North Carolina, showed that "lead yield
is related to land use and the increased traffic density
that corresponds to commercial development," so that
"the yield of lead from the predominantly residential
area W was one-half of that from the more commercially
developed area N." Most of the lead was presumed to be
contributed from surface wash and to be the product of
exhausts of internal combustion engines of motor
vehicles using leaded gasolines. The "annual yield of lead
was determined to be 1,190 pounds per square mile per
year" with "the more commercialized and densely
urbanized portion of the basin studied yield [ing] lead at
twice the rate of the less intensively developed portion
of the basin, in direct proportion to the area of paved
surfaces," thus indicating the danger to children in inner
city areas (14).
Another reason why the removal of lead-based house
paints will not solve problems for inner city children is
indicated in a study by the child psychiatrist Reginald
Lourie. Dr. Lourie's study shows that children suffering
from lead ingestion are also victims of the symptom pica
(L., magpie) which compels them to eat or at least put
in their mouths all sorts of unsuitable substance, most
commonly dirt which, considering lead levels in the
inner city, will be high in lead. Psychiatrically these
children suffer from neglect and the speediest, indeed
the only effective, cure for this symptom is to induce
the mother or the mother surrogate to show interest in
the child. Nothing can reverse the damage done by what
has been eaten, but at least the eating of unsuitable
substances is stopped prospectively. Conditions such as
these are hard to legislate about; but it helps explain
why lead poisoning has not been found in many groups
of children, even though lead-based paints are in their
dwellings and lead-loaded soils are in their yards. These
children are not pica sufferers because of a more
fortunate parent-child relationship (15). Such
psychiatric data does not justify the continued use of
lead in interior paint; but it does help explain the
unevenness of the problem and why the ban on
lead-based paint will not provide a complete answer.
Congress temporized by enacting the Lead-Based Paint
Prevention Act (16). Despite its ambitious name, its
primary functions are to grant research aids for studying
the effects of lead-based paints and for providing
education for persons resident in areas where the use of
lead-based paints poses a particular problem, as well as
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181
to assist them in seeking employment although damaged
by the presence of such paint. The United States Pub lie
Health Service has issued a regulation as a notice of
proposed rule making to ban lead-based paint in federal
and federally assisted construction, which would have
broad prospective effect (17). The United States Food
and Drug Administration has proposed declaring certain
heavy metal-containing paints and other surface coatings
subject to a special labeling for child protection (18).
They also propose to classify paints containing more
than minute traces of lead as among "Banned Hazardous
Substances" (19). The late Congressman Ryan proposed
to ban the use of lead-based paint; but, to my
knowledge, this has not been acted upon favorably (20).
Ultimately, however, if the public pressure continues,
lead-based house paint will be banned, at least for
interior uses; persons using it illegally will be subject to
criminal punishment; and, clearly, there will be pressure
for public funds to be used to remove the accumulation
of lead-based paints in housing interiors. All the above
will be years in becoming effective. Once the image is
established in the public mind of children having their
mental faculties destroyed or impaired for life, by having
eaten paint flakes while in their cribs, the politics of the
image become very plain. And law is a consequence of
politics.
Lead in gasoline is another common puWic concern
today, and there is great pressure to compel refiners to
remove it. Lead was introduced for its "anti-knock"
properties to meet the needs of the higher pressure
engines in the late 1920's and for this purpose has
retained its popularity. The public has shown little
interest in voluntarily using as alternatives the lead-free
gasolines on the market, including many introduced in
the past two years (21). Many say this is because they
have not been adequately advertised and others say it is
because they do not give the public the performance
they want in gasoline. In any event, the pressure has
been on for some time to ban the use of lead in gasoline.
In 1971 President Nixon, perturbed by the fact that
95 percent of the total lead emitted into the atmosphere
comes from autos, proposed a tax on lead which would
make leaded gasolines less competitive with the
nonleaded variety (22). His then Secretary of the
Treasury called lead "a clear and present danger" to the
national health and backed a proposal for .taxing it in
gasoline (23). The President in his 1972 environmental
message included a statement that federal regulatory
measures must be taken in the future against the dangers
of lead released into the environment (24). The Clean
Air Act, as amended, had already stated that
manufacturers of fuels and fuel additives could be
required to register any additives used in fuel sold in
interstate commerce (25). Clearly, this was meant to be
preparatory to further legislative action since the
registration in this act was solely for the purpose of
gathering information and no regulatory activity was
involved.
In February 1972 the Environmental Protection
Administration issued a regulation on fuels and fuel
additives relating to lead and phosphorus in motor
vehicle gasoline (26). Basically it prescribed that there
should be a decrease of such materials in gasoline and
that by July 1, 1974 there be available on the market
gasolines free of these substances, capable of being used
in 1975 model cars (27). At about the same time, the
EPA issued a paper in connection with leaded gasoline
which was an analysis and summary of the medical and
scientific evidence on the health hazards of air-borne
lead (28). This was not a criteria document, but it was
designed to underscore the reasons for the EPA's action.
Recently, the EPA has also begun to become concerned
with the quality of diesel fuel, and an across-the-board
federal interest in all motor vehicle fuels is to be
expected. The public concern does not show any signs of
political abatement, despite the apparent lack of
enthusiasm at the market level for lead-free gasolines.
One can anticipate that there will be further regulations
and statutes controlling the use of lead in fuels, indeed,
probably eventually banning its use before the end of
the present decade (29).
The public is continuously assailed by the fear of
possibly harmful effects from lead. Recently, the
importation of cookware and crockery from abroad,
either made of a clay containing a high quantity of lead
or with glazes having high quantities of lead and
cadmium which are released either by heat or reaction
with the organic substances in the dish, have attracted
public attention. The warnings against both foreign and
domestic ware that is dangerous under these conditions
have been spread around and Senator Schweiker has
introduced legislation to control the amount of lead and
cadmium which may be released from ceramic or enamel
dinnerware (30). Many persons have ceased to use
Mexican pottery or peasant-ware imported from the
Mediterranean because of these fears, even though any
usage other than fairly regular would probably be safe.
This merely underscores the fears with which the public
continuously finds itself surrounded in relation to the
metal lead in daily life.
MERCURY
Mercury is another substance high on the list of public
fears. Litigation has been high in relation to this metal,
notably the efforts of the State of Ohio to prevent its
further dumping into waters draining into Lake Erie and
to impose on previous dischargers the costs of cleanup
(31). Environmental problems have affected the
popularity of mercury and have very nearly halted
United States production of it. In July 1965 the price
was 725 dollars for a 76 pound flask. In May 1972 the
price was 175 dollars, the lowest price for mercury since
1950. American use had dropped from 77,370 flasks in
1969 to approximately 48,000 in 1972. In 1970, there
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were 79 United States mines which sank to fewer than
30 by 1972. To meet expenses of production in the
United States, the price must be somewhere between
225 and 250 dollars, in 1972 per flask. Changes in
chlorine production have simply eliminated the use of
mercury rather than seeking to control its use. World
production of mercury, however, has dropped only
slightly as the result of the American experience; and,
conversely, the world's biggest producers, Spain and
Italy, have upped production. Interestingly, according to
the Wall Street Journal, the industry believes "nobody
can afford research ... to find nonpolluting uses for the
metal," due to its present high production costs and low
price (32).
The problems of mercury have acted to panic the
public because of isolated horror cases. The use of
mercury-dressed seeds either to make bread or to feed
hogs has caused terrible harm to persons eating either
the bread or the pork. In Japan, where residents of
Minamata Bay eat mostly fish taken out of a very
confined water body into which mercury wastes flow
from a chemical plant, the harm has been extensive (33).
"Mad Hatter's disease," because of its damage to mental
process, nerve", and important bodily processes one the
public long has feared; and the pressure against mercury
users will rise. Its use for seed dressings will probably be
entirely eliminated, though this has used less than 3
percent of the domestic consumption of the metal.
Labeling does not seem adequate to protect the rural
agricultural laborer who has been the chief victim of the
misuse of mercury-dressed seed. Modernization of
techniques using mercury also seemed designed to
eliminate it from the economy in anything like its
present employ, even though as late as mid-1969 the
United States Bureau of Mines insisted the use of
mercury could be expected to increase indefinitely at up
to 4-1/2 percent per year in industrialized nations. Paint
manufacturers, although insisting they cause no
problem, arc: considering eliminating mercury from their
products (34).
The entire public attitude has changed radically since
1969 on the subject with the announcement of relatively
high mercury contents in Lake Erie fish. "Minamata Bay
sickness" loomed large in the public mind as a possibility
in the United States. It has not been put at rest by
subsequent investigations by paleoecologists which have
shown mercury concentrations in museum fish
specimens (35) and by studies of similar specimens to be
in a probable decline since 1900 in the Unites States,
possibly resulting from the lack of the use of soft coal.
Nor have Americans been impressed by being told only
heavy fish eaters from one source are most vulnerable, a
condition of vulnerability not likely for the average
American who buys from a national market and is not
much of a fish eater anyway (assuming he is not on the
Norman Jolliffe diet). Mercury is cumulative, as the old
doctors who practiced calomel-and-castor-oil medicine
knew; and this fact is cumulative in the public mind.
Because of this EPA has listed mercury along with
asbestos and beryllium under the Clean Air Act as one of
the three hazardous air substances (36). The ability of
organisms to concentrate mercury is particularly noted
in the regulations, and this is given as one of the reasons
to be concerned with all mercury emitters, even those
which might appear to be small. Anyone advising a
corporation, therefore, would likely tell them, however
small their use of mercury, to try to eliminate it
altogether if possible. Why keep troublesome trifles
around? Especially when they do not prove trifling in
ecologic, industrial, or litigation costs.
ASBESTOS
A mineral which has created far less perturbation in
the public mind, and yet is listed by the EPA as one of
the three hazardous substances under the Clean Air Act,
is asbestos. In medical literature, asbestosis, the disease
associated with exposure to asbestos in the air, has been
identified since 1924; but it was not until forty years
later, when the New York Academy of Sciences held a
conference on the biological effects of asbestos that the
full impact of the mineral on public health was
understood (37). It has been only since 1964. therefore,
that the efforts have been mounted to control the use of
asbestos from the point of view of protecting public
health.
Asbestos is a mineral whose effect cuts across both
workmen's compensation law (38) and the legal
consequences of asbestos use as it affects members of
the general public. Clearly the ones most endangered by
asbestos are those whose employment regularly causes
them to come into contact with it (39). However,
regular usage need not be prolonged in order for the
results to be serious and the effect may be so long
delayed that the individual involved may have forgotten
when he suffered exposure to the mineral. The Federal
Occupational Health and Safety Act has lain down far
tougher general rules than had previously prevailed in
most states, and it is important today in the type of
protection a worker may anticipate in his work
conditions (40). Industrial hygiene legislation is designed
to head off the need for workmen's compensation for
industrially related illnesses. It removes the cause of the
illness in the affected industrial processes or it requires
that the worker be protected in his work situation from
the effects of the work process with which his
employment requires him to deal (41). The need for
workmen's compensation indicates either an
unawareness that a problem initially existed, a failure of
the law to cope with the problem once it was discovered,
or a technological impossibility of protecting the
worker, coupled with a socio-economic decision that the
process involved is too important to be banned because
of the risks involved.
Outside of this, however, are the possible risks to the
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183
general public who are not exposed to asbestos in their
employment situations (42). Commonly today in the
construction of high-rise steel-frame buildings, asbestos
is sprayed on the structure prior to closing it within its
poured concrete envelopes and curtain walls. Before
regulations were adopted (one of the toughest being
New York City's ordinance which went into effect in
February, 1972) (43), the effect was of a wintry snow
scene. The tarpaulin coverings around the spraying
process have proven totally inadequate in confining the
asbestos, with the asbestos sifting out from under the
canvas to blow loosely about the streets. It is normally
both amosite and chrysotile asbestos, mixed with rock
wool, glass fibres, and often plaster in order to make it
fireproof, so that plaster dust today contains a heavy
asbestos burden (44). What is the effect of the public
being exposed to such a mixture in the air over the
several weeks or months such construction takes,
considering the fact some persons live as well as work in
the vicinity of such construction?
This is not an easy question to answer. First of all,
many Americans are mobile. That is, they may live near
such a construction site, but their work, recreation, or
other activity may cause them to be absent during the
hours of construction activity. Others may be employed
by a firm in the vicinity, but their conditions may cause
them to be elsewhere or may take them in or out of the
area. Furthermore, the increasing use of air conditioning
acts to screen out from interior rooms the asbestos
fibres. Very few Americans would get the exposure of
South African laborers who both lived and worked near
asbestos, lacked mobility, and hence were massively
exposed. But even brief exposure to asbestos has
sometimes been sufficient to initiate the disease (in one
case, a six-week temporary job wrapping asbestos
insulation around heating pipes triggered a
mesothelioma fatal 23 years later) (45), and a
no-exposure level for the general public would be best.
After all, the best efforts will not prevent present
generations from inhaling more asbestos than previous
generations; and exposure of school children is
particularly to be avoided since exposure at an early age
produces poorer prognostications than at later ages.
Because of the impossiblity under current technology
of sampling and measuring asbestos in the ambient air or
in emission gases, the regulations of the EPA are
expressed as requirements for the operation of specific
control equipment or, where no control equipment is
available, through prohibition of the use of asbestos
(46). This is justified since the most dangerous asbestos
particles are the submicroscopic and highly respirable
variety which cannot be seen and whose presence may
be unknown except as the individual may suffer a vague
respiratory discomfort current with inhaling them (47).
The consequence of such an approach is the emphasis
that must be put upon the maintenance of the
equipment, the adequacy of inspection, and the reaction
of the legal machinery in its willingness to impose
serious civil consequences upon equipment users who
have failed to maintain it and whose failure has caused
harm to individuals. The trouble with this last approach
for effectiveness has two aspects: The individual either
not knowing of his exposure or else not remembering or
relating the exposure to the harm (said unawareness
extending to his physician in terms of diagnosis) and the
time lag between exposure and onset of the disease
producing burdens of proof (48).
Americans are not a maintenance prone culture. Any
system which puts its reliance in maintenance of an
equipment system and bureaucratic inspection to keep
the maintainers up to minimal standard is a system that
is in for more failures than successes, if previous
experience in other areas is a guide. Further, many of
the contractors who work with asbestos are often the
sort of undercapitalized, transient, indifferent
entrepreneurs most likely to become scofflaws. The
result is that the public risk from asbestos is likely to
remain high until technology gets much better.
BERYLLIUM
The third hazardous air pollutant nationally singled
out by the EPA under the Clean Air Act is beryllium.
Industry long resisted the allegation that the use of
beryllium in industrial processes could be productive of
any long-term adverse effect leading to permanently
debilitating illness. I recall observing, in the mid-1960's
in northeastern Pennsylvania, a series of workmen's
compensation hearings before a Commonwealth
examiner in which employers conceded the cause of
"Black Lung." But they vigorously resisted the
imputation that the claims made for compensation for
illness imputed to beryllium were allowable on the basis
of the innocence of the mineral. For this reason, the
courts allowed counsel for claimants to introduce into
evidence, through the medium of hypothetical questions
put to experts called by the claimant, whether a
"conference of chemists and medical men had made any
definite finding that beryllium was the sole cause of
berylliosis." By the end of the decade this was a
recognized illness for purposes of compensation under
workmen's compensation laws (49).
The danger to the public was harder to establish, but it
was finally determined that those residing near plants
employing beryllium were in considerable danger.
Indeed, as industrial hygiene improved within the plants,
their dangers were probably greater than the workers.
This is not an unusual phenomenon. Once the cause of
an industrial illness is established, the insurance carrier
of the employer becomes insistent upon alterations in
industrial processes to mitigate extent of liability. Also
the chances go up markedly for an employer, who
refuses to respond to this pressure, to be liable for the
far greater coverage of gross negligence or reckless and
wanton misconduct under the common law of tort. The
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CYCLING AND CONTROL OF METALS
result is better conditions for the workers than prevail
for the residents living in houses within several hundred
feet of the plant.
The "known major sources of beryllium are extraction
plants, machine shops and foundries handling beryllium
or beryllium-containing alloys, ceramic plants using
beryllium, rocket propellants containing beryllium, and
incinerators burning beryllium-containing waste" (50).
Because of the value of berylh'um to harden substances
to which it is added, its presence is common and likely
to increase so that the above list is one that indicates
fairly common contact with the general public. It
indicates further some difficulty in enforcing any laws
designed to protect the public or, if protection fails, to
guarantee the person hurt a financially responsible entity
to be the respondent in any damage action. In the latter
regard, it does very little good to make liability for harm
clear when the one liable is not capable of fiscal
responsibility.
LESSER TRACE METALS
Other trace metals are of sufficiently narrow impact,
or their consequences up to this point sufficiently
unknown, so to treat them individually would be
unsupported by adequate legal materials. Chrome dust,
for example, is a serious problem in industrial processes,
but it has not been one that much affects the public at
large by any deteriorating of the atmosphere.
Nevertheless, the Federal Occupational Health and
Safety Act has a table of air contaminants including
chromium, copper, iron (oxides), lead compounds,
nickel, tin, zinc compounds, and others (51). One of the
problems is the sharp increase in the use of certain trace
metals in industrial processes which were unknown until
very recently. For example, vanadium is now used in 18
compounds of itself in a wide variety of commercial
processes (52). What is the effect of it? People have
always had traces of vanadium in their systems but now
it is increasing. What this means is simply not known
medically and will not be until more experience is
accumulated — experience which could be good or bad.
Most of these trace metals are included for purposes of
legal and public concern under the rubric of "toxic
substance," which of course is a far larger category than
trace metals. In his 1971 Environmental Message,
President Nixon proposed that the EPA be empowered
to restrict the use or distribution of any substance which
the EPA Administrator finds is a hazard to human health
or the environment (53). This was a rather sweeping
delegation of legislative powers, but analogous to what
has happened in workmen's compensation legislation
where the legislatures have stopped listing specific
diseases or causes of disease and have gone over, instead,
to merely indicating that all illness contracted in relation
to employment is compensable. In his 1972
Environmental Message, the President proposed a Toxic
Wastes Disposal Control Act which, under EPA
supervision, would establish Federal guidelines for state
programs to regulate the disposal of harmful wastes (54).
This type of concern at the chief executive level is
correlated to concern at lower federal bureaucratic
levels. The United States Bureau of Mines has a
metallurgy program based upon the need to maximize
the efficiency of metallic use and to minimize the
quantities discharged as pollutants and wasted in the
industrial process (55). The metals specifically
mentioned are zinc and lead, but it would be equally
applicable to others, particularly as it becomes evident
that the bulk of supply for some metals in the future
will be from recycling and reclaiming processes (56). The
United States Department of Transportation has a
Hazardous Materials Regulations Board which has issued
an advance notice of proposed rule making which
classifies certain hazardous materials on the basis of their
health hazards; and these must include at least some of
the trace metals (57). The Federal Council on
Environmental Quality issued in April 1971 a booklet on
toxic substances, pointing out their dangers and urging
measures be taken to control the harmful side effects in
their careless employment. Other examples could be
pointed out in the federal structure of similar import
since, once interest is high in the executive, judicial, and
legislative branches of the government, it is evident that
the administrators must indicate a zeal at least as
significant as shown by those who generate the basic
decisions, statutes, or orders within which the daily
routines of public administration must be carried on
(58). Whatever their historic inadequacies, it is the
administrators who properly belong in the front line of
the public's defense against the sort of risks posed by
trace metals in the environment.
The law, as is to be expected from a discipline
responding to outside pressures, has many avenues to
resolving similar problems. Its relations with trace metals
are no different in this respect. Just as one would look in
the indices under "toxic materials" as well as
atmospheric pollution, water waste control, or the
names of the individual metals themselves, so also would
one consider the heading "hazardous substances" or
"dangerous properties of industrial materials" or similar
language which occurred at some time to those pushing
for a legal response to a health or environmental
challenge. Often the legislative response is a narrow one,
as in the Hazardous Substances Act, which does not
cover the raw materials from which household products
or toys are made (59), or in the old Water Pollution
Control Act which authorized the President to designate
hazardous substances and to recommend methods for
their removal from the water (60). Anyone doing
research in this area must consider such statutes as these
if he is to cast his legal investigative net wide enough to
be sufficient. Too narrow a point of inquiry will not cut
an aperture wide enough to be useful.
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185
CONCLUSIONS
Indeed, perhaps this paper suffers from this very
narrowness against which I warn. As I said at the
beginning, trace metals are generic in their problems to
all situations in which some small quantity is discharged
into the environment by an economic activity. In this
case, environment includes air, water, soil, and the living
cells, which, paradoxically, must count in the cells of
what Claude Bernard called the "interior milieu" of
humankind. Probably it is impossible in this situation to
make any final separation of issues of human health and
environmental fitness. For this reason, at one time, both
public health and environmental law were so close as to
be the same; and only the growing complexity of each,
acting to prevent any one scholar from mastering them,
has forced their separation one from the other.
In any comments on trace metals and the law, there is
an interlocking of workmen's compensation, industrial
hygiene, and environmental protection that makes it
very difficult to steer safely through. Probably, from the
lawyer's viewpoint, the subject trace metals, or even
trace substances, is one that is insufficiently legalistic in
its conceptualization; and for lawyers such terms as
negligence, reasonable risk, etc. would be easier to deal
with. However, subjects do not agitate society in the
language that they perturb lawyers. Often, therefore, it
is necessary to address the problem in words that are
clumsy to the lawyer but which express what is
uppermost in the mind of the public. The risks of trace
metals are among these. Clumsy as this paper is because
of this fact, nevertheless I believe the effort was worth
making, slight as the result may be.
REFERENCES
1. Technology Assessment, 1970. Hearings,
Subcommittee on Science, Research and
Development, House Committee on Science and
Astronautics, 91st Cong., 2nd Sess., No. 21, May
20,21, 26, 27; June 2, 3,1970.
2. Taylor, G. R., The Doomsday Book, 94-97 (with
citations of sources on p. 301), 1970; Arvill, R.,
Man and His Environment (rev. ed.) 92, 94,
1969; Rienow, R., with L. T. Rienow, Man
Against His Environment, ch. 17, 1970. These
are popular works dealing with these
environmental situations.
3. Asbestos may be either an amphibole or a
serpentine. Modern commercial asbestos in the
United States is a mixture, commonly amosite
and chrysotile respectively.
4. Traditionally, according to Cato, the Romans had
fortified their wine with brine, so the fashion
was long established for a metallic aftertaste and,
possibly, even the effects of over salting the
system by ingestion of the brine along with the
dehydration from the alcohol, Mommsen, T.,
History of Rome, vol. Ill, 123,1894.
5. The use of lead (for whiteness), arsenic (for
smoothness), and antimony (for lustre) in
cosmetics was common, while belladonna (for
enlarged pupils and shining eyes) was used in the
Renaissance. The risks in modern cosmetics are
quite different, May, B., How to Live in Our
Polluted World, 36 et seq., 1970.
6.4 CCH Clean Air and Water News, 629-630,
September 28,1972.
7. Rubinov, I. M., The Quest for Security, 81,1934.
8. Churchman, W. H., The Air We Breathe, 1871,
recounts industrial air conditions of the day.
9. Rubinow, op. cit., 83, reciting the five stages in legal
response leading to a compensation system that
were present in both Europe and America.
10. Arvill, op. cit., 98-99.
11. An interesting survey is Cleaning Our Environment, a
Report of the American Chemical Society,
Subcommittee on Environmental Improvement,
Committee on Chemistry and Public Affairs,
1969, especially 26, 128-131, and 176 for the
presence of trace metals in air pollution, waste
water renovation, and solid waste.
12. See West's Key Numbers, Workmen's Compensation,
527 (inhalation of fumes, gas, and particles); 538
(lung diseases); and 549 (occupational diseases in
particular).
13. A 27 - city United States Public Health Service
Study revealed 400,000 children had
dangerously high lead levels in their blood. Of
the black children surveyed 33 percent and of
the white 11 percent had such levels, leading to
theorization about cultural and genetic
differences in susceptibility, New York Times,
21, June 15,1972.
14. Bryan, E. H., Quality of Storm Water Drainage from
Urban Land, 8 Water Resources Bull, 578,
583-588,1972.
15. Professor Lourie described his research at the
International Seminar on Human Settlements,
held July 20, 1972, at the Athens Center of
Ekistics, Athens, Greece. He is professor of
psychiatry and child health and development,
George Washington University, Washington, D.
C.
16. 42 USCA sec. 4801 (P. L. 91-695, 84 Stat. 2078).
17.42 CFR Part 90; 36 F. R. 21833 (November 16,
1971). The United States Dept. of Housing and
Urban Development on February 18, 1972,
temporarily exempted itself from its own similar
regulation, New York Times, 11, April 24,1972,
"pending study on best methods of eradicating
lead-based poisoning."
18.21 CFR Part 191; 36 F. R. 20985 (October 28,
1971).
19. 36 F. R. 20936.
20. HB 16267, to amend the Lead Based Poisoning
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CYCLING AND CONTROL OF METALS
Prevention Act; referred to House Banking and
Currency Committee.
21. Columbus Dispatch, 41A-4, January 17, 1971,
quoting Oil Daily and John Huemmerich,
executive director, National Congress of
Petroleum Retailers.
22. This appeared in The President's 1971
Environmental Program (March 1971), excerpted
in Reitze, A. W., Jr., Environmental Law (2nd
ed.) Ill, 74-75, 1972. See also the president's
1971 environmental message in BNA
Environmental Reporter, 21:0322, February 8,
1971.
23. 28 Cong. Q. Wkly Rep. 2254, (September 18, 1970).
24. BNA Environmental Reporter, 21:0429 (February 8,
1972).
25.42 USCA sec. 1857f-6c, PL 91-604, and 81 Stat.
502, sec. 210. The Clean Air Act first passed in
1962 and its predecessor the Air Pollution
Control Act in 1955. See 40 CFR Part 79,
Subpart B, 36 F. R. 22419 (November 25,
1971).
26. 40 CFR Part 80; 37 FR 3882 (February 17, 1972).
27. Reitze, op. cit., Ill, 74.
28. BNA Environmental Reporter, 31:2641 (February
22, 1972).
29. Reitze, op. cit., Ill, 75-76.
30. Senate Bill 3136, to amend the Federal Food, Drug,
and Cosmetic Act. Its companion bill is HB
12,958, introduced by Congressman Horton.
31. Ohio v. Wyandotte Chemicals Corp. et al, 401 U. S.
493,1971.
32. Croft, C. D., Mercury's Run-in With Ecology, Wall
Street Journal, 22, May 22,1972.
33. See the National Geographic Magazine, vol. 142,
507-527, October 1972, Putman, J. J.,
Quicksilver and Slow Death.
34. Croft, op. cit.
35. Dr. Edwin Wilmsen of the University of Michigan
found, in fish samples ranging in age from 300 to
2000 years, levels of mercury similar to those in
today's fish, New York Times, 16, December 28,
1971.
36.40 CFR, Part 61; 36 FR 23239 (November 30,
1971), pursuant to sec. 112 of the Clean Air Act
as amended, 42 USCA 1857, P. L. 91-604, 84
Stat. 1705.
37. Brodeur, P., Asbestos and Enzymes, 14, 27,1972.
38. West's Key Numbers, Workmen's Compensation
1396 (on medical testimony in general), 1392
(claimant's testimony), 1509 (lung diseases).
39. For example, H. B. 2516, Asbestos Workers Health
Protection Act, to promote the safety of workers
engaged in making asbestos products, which
illustrates proposed legislation.
40. Occupational Safety and Health Standards, 29 CFR
1910.93a (asbestos dust); revised 37 F. R. 332,
(January 18, 1972), 11320, (June 6,1972). The
Occupational Safety and Health Act is in 29
USCA sec. 651 et seq.; P. L. 91-596; 84 Stats.
1590.
41. See, United States Dept. of Labor, Bureau of Labor
Standards, Part 1518, Safety and Health
Regulations for Construction: Standard for
Exposure to Asbestos Dust, 36 F. R. 23207
(December 7, 1971).
42. The National Academy of Science on October 8,
1971 warned that the major sources of
man-processed asbestos emission must be
controlled "or asbestos ambient air
concentration in some localities would approach
those encountered by workers in the asbestos
industry," Reitze, op. cit., Ill, 11.
43. As of February 23, 1972 in New York City "the
spraying of fireproofing materials containing
asbestos on the structural steel of buildings" was
banned and similar bans in 1972 were imposed in
Boston, Chicago, and Philadelphia, Brodeur, op.
cit., 137.
44. Ibid., 49.
45. Ibid., 47-48.
46. 40 CFR, Part I; 36 F. R. 23239 (December 7,1971).
47. Brodeur, op. cit., 50, citing Dr. Irving J. Sslikoff,
director, Environmental Sciences Laboratory,
Mount Sinai School of Medicine, City University
of New York.
48. Remember the burden of proof is generally on the
claimant to show the harm is compensable,
Aetna Cas. etc. cc. v. Jenhuson, (Tex. Civ. App.,
1971), 469 S.W.2d 423.
49. Ricciutti v. Sylvania Electric Products (Mass.), 178
N. E. 2d 657 (1961). See also Biglioli v. Durotest
Corp., (N. J. Super. Ct., App. Div.), 129 A. 2d
727,1957.
50. 40 CFR, Part I, 36 F. R. 23239 (December 7,1971).
51. 29 CFR, Part 1910, subpart G (Occupational Health
and Environmental Control), sec. 1910.93; Table
amended 37 F. R. 11320 (June 6, 1972).
52. Reitze, op. cit., IV, 87.
53. BNA Environmental Reporter, 21:0324 (February 8
1971).
54. Ibid., 21:0422.
55. Ibid., 51:4305.
56. McHale, J., The Future of the Future, 225, 1969,
citing R. Buckminster Fuller. See also the
remarks of Max Spendlove, director of research,
United States Bureau of Mines Metallurgy
Research Center on the 250 to 300 million tons
of annual urban refuse as a source of materials,
Columbus Citizen-Journal, 4, October 17 1972
57. 49 CFR Parts 170-189; 35 FR 8831 (June 5,'\970).
58. See Sax, N. I., with Dunn, M. S., et al., Dangerous
Properties of Industrial Materials (3rd ed 1968)
59. 15 USCA 1261-73;P.L. 91-601; 84 Stat. 273.
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LAW AND TRACE METALS 187
60.33 USCA 1162, Federal Water Pollution Control October 18, 1972, P. L. 92-500, are sees. 115
Act, sec. 12, added in 1970, P. L. 91-224, sec. (in-place toxic pollutants), 307 (toxic and
102; Reitze, op. cit., IV, 81-82. The provisions pre-treatment effluent standards), and 31 l(b) (2)
of the new Federal Water Pollution Control Act, (A) (hazardous substances).
I wish to thank my student, Mr. David Monroe, for his
assistance.
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