EPA 560/6-77-031
MULTIMEDIA LEVELS
MERCURY
SEPTEMBER 1977
ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF TOXIC SUBSTANCES
WASHINGTON, D.C. 20460
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EPA-560/6-77-031
MULTIMEDIA LEVELS
MERCURY
September 1977
BATTELLE
Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201
Vincent J. DeCarlo
Project Officer
Contract No. 68-01-1983
ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF TOXIC SUBSTANCES
WASHINGTON, D.C. 20460
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NOTICE
This report has been reviewed by the Office of
Toxic Substances, Environmental Protection Agency, and
approved for publication. Approval does not signify
that the contents necessarily reflect the views and
policies of the Environmental Protection Agency. Mention
of tradenames or commercial products is for purposes of
of clarity only and does not constitute endorsement or
recommendation for use.
I'
ii
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PREFACE
This review of the environmental levels of mercury was conducted
for the U.S. Environmental Protection Agency, Office of Toxic Substances,
under Contract No. 68-01-1983. It involved (1) the review and evaluation
of existing monitoring data and (2) development of an integrated data
package. Information sources were identified from computerized and
manual searches. Data were obrained from specialized data centers;
university programs; federal programs, state programs; the Smithsonian
Science Information Exchange; EPA's Storet, SAROAD, and NASN data centers;
the USGS and Fish and Wildlife Service; and from readily available open
literature.
Information gathered included mercury concentrations in air, surface
and drinking water, groundwater, soil, food, sediment, sludge, aquatic and
terrestrial organisms, human tissues, and body fluids. Details were
obtained on the methods of sample collection, interferences, meteorological
data, and analytical methods employed.
iii and iv
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TABLE OF CONTENTS
1. INTRODUCTION 1-1
Physical and Chemical Properties 1-1
Production and Uses of Mercury 1-1
Sources of Environmental Contamination by Mercury .... 1-5
2. MERCURY LEVELS IN THE ENVIRONMENT 2-1
Air 2-1
Water and Sediments 2-10
Drinking Water 2-23
Sludge 2-25
Rocks and Soils 2-27
Terrestrial Biota 2-31
Aquatic Biota 2-43
3. BEHAVIOR IN THE ENVIRONMENT 3-1
Transformation in Nature 3-1
Geochemical Cycle of Mercury 3-6
Food Chain Transport 3-14
4. OCCURRENCE OF MERCURY IN FOOD 4-1
Mercury Levels in Fish 4-1
Mercury Levels in Foods Excluding Fish 4-2
Mercury in the Market Basket and Total Diet 4-11
Estimated Dosage 4-12
5. MERCURY IN MAN 5-1
Mercury Vapor 5-1
Mercuric Mercury 5-3
Alkylmercurials 5-6
Mercury Level in Human Tissues 5-7
6. REFERENCES 6-1
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FIGURES
Number
1.1 Commercial U.S. mercury deposits
1.2 Projected mercury consumption in the United States by end
use
1~6
1.3 Projected mercury consumption in the United States by end
use, Year 2000 1-7
1.4 Past and probable future trends in final disposal of
mercurials 1-12
2.1 Theoretical saturation concentrations of mercury in air . . 2-2
2.2 Location of hydrologic benchmark stations maintained by
the U.S. geological Survey 2-13
2.3 Mercury levels in U.S. surface waters, 1970-1974 2-18
2.4 U.S. Geological Survey classification of major drainage
basins in the United States 2-19
2.5 Mercury levels in Baltimore Harbor sediments 2-21
2.6 Frequency distribution of mercury in Great Lakes sediments. 2-24
2.7 Levels of mercury in fishes, National Marine Fisheries
Service Microconstituent Resource Survey 2-54
3.1 Cycle of mercury interconversions in nature 3-2
3.2 Pathways of mercurial breakdown and methylation in nature . 3-5
3.3 Generalized geochemical cycle of mercury in natural
systems 3-7
3.4 Tentative present-day cycle of mercury 3-9
5.1 Mean Blood Levels of Mercury Versus Time-Weighted Averages
of Mercury in Air 5-4
5.2 Urine Levels of Mercury Versus Time-Weighted Averages of
Mercury in Air 5-4
5.3 Elimination of total mercury from hair, blood cells, and
plasma in six subjects 5-8
VI
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TABLES
Number Page
1.1 United States Domestic Mercury Production 1-3
1.2 Consumption of Mercury in the United States 1-4
1.3 Total Mercury Losses in 1973 for Conterminous U.S. by
Sector and SIC Category 1-8
2.1 A Comparison of Mercury Concentrations in the Air as a
Function of Species and Location 2-4
2.2 Elemental and Total Atmospheric Mercury Concentrations in
Three North Carolina Cities 2-5
2.3 Summary of Atmospheric Mercury Measurements at Selected
U.S. Locations 2-7
2.4 Ambient Outdoor Mercury Concentrations in Selected U.S.
Cities 2-10
2.5 Summary of California Atmospheric Mercury Measurements. . . 2-11
2.6 Mercury Levels in Surface Waters of the United States . . . 2-14
2.7 Mercury Levels in Groundwater of the United States 2-16
2.8 Summary of Mercury Concentrations in U.S. Waters 2-17
2.9 Mercury Concentrations in the Ohio River and Some of its
Tributaries 2-22
2.10 Mercury in Public Drinking Water Supplies 2-26
2.11 Mercury Content of Rock Types 2-28
2.12 Concentration of Mercury in Urban and Suburban Soils. . . . 2-30
2.13 Mercury Levels in Terrestrial Mammal Hair 2-33
2.14 Mercury Levels in Starlings (Sturnus vulgaris); 1970, 1971,
and 1973 2-35
2.15 Mercury Levels in Woodcock (Philohela minor) liver,
1970-1971 2-39
2.16 Mercury Levels in Black Duck and Mallard Wings (Amar
Rubripes and A. platyhyncher). 1969-1970 2-40
Vll
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TABLES (Continued)
Number Page.
2.17 Mercury Levels in Duck Breast Muscle, 1970-1971 2~42
2.18 Mercury Levels in Birds of Lake St. Clair, Michigan .... 2-44
2.19 Distribution of Mercury in Tissues of Oregon Pheasants. . . 2-46
2.20 Mercury and Methylmercury Content of Pheasant Breast Tissu
Tissue 2~46
2.21 Levels of Mercury in Fish from Region 1, National Pesti-
cides Monitoring Program, 1969, 1970, and 1972 2-48
2.22 Levels of Mercury in Fish from Region 2, National Pesti-
cides Monitoring Program, 1969, 1970, and 1972 2-49
2.23 Levels of Mercury in Fish from Region 3, National Pesti-
cides Monitoring Program, 1969, 1970, and 1972 2-50
2.24 Levels of Mercury in Fish from Region 4, National Pesti-
cides Monitoring Program, 1969, 1970, and 1972 2-51
2.25 Levels of Mercury in Fish from Region 5, National Pesti-
cides Monitoring Program, 1969, 1970, and 1972 2-52
2.26 Levels of Mercury in Fish from Region 6, National Pesti-
cides Monitoring Program, 1969, 1970, and 1972 2-53
2.27 Levels of Mercury in Plants of Lake Powell, Arizona .... 2-58
3.1 Global Cycling of Mercury 3-8
3.2 Maximum Mercury Concentration in Air Measured at Scattered
Mineralized and Nonmineralized Areas of the Western
United States 3-11
3.3 Concentrations and Concentration Factors of Mercury in
Water and Edible Aquatic Organisms 3-15
3.4 Biological Magnification of Mercury in the Aquatic Food
Chain 3-15
4.1 Summarization of Fish Type by Total Mercury Content .... 4-3
4.2 Mercury Residues in Canned Sea Food 4-4
4.3 Mercury Content of Selected Food Fish 4_5
viii
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TABLES (Continued)
Number Page
4.4 Mercury Content of Fresh Fruits and Vegetables
Commercially Available in Denton, Texas 4-7
4.5 Mercury Content of Foods (Excluding Fish) 4-8
4.6 Mercury Content in Foods: National Pesticides Monitoring
Program Market Basket Data 4-13
4.7 Summary Values for Mercury Levels in Nonfish Commodities. . 4-14
4.8 Estimated Mercury Dose Through Standard Diets 4-15
4.9 Mercury Exposure from the Diet of Fish Eaters 4-17
4.10 Mercury Exposure from the Diet of Weight Watchers 4-17
5.1 Mercury Vapor Concentration in Naval Dental Operating
Rooms 5-3
5.2 Mercury Content of Selected Human Tissue 5-10
5.3 Concentration of Mercury in Human Hair—Persons of Limited
and Known Exposure 5-11
ix and x
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EXECUTIVE SUMMARY
A determination and evaluation of environmental levels of mercury,
based on a review of the literature and other information sources, is
presented in this report.
The annual emission of mercury to the environment is approximately
1,525 metric tons (1973 estimate). About 4 percent of this comes from
mining and smelting of mercury and other ores, 21 percent comes from
manufacturing and processing operations, and 65 percent comes from the
use and disposal of mercury products. The remaining 10 percent comes
from inadvertent releases resulting from mercury being a contaminant in
other substances, especially coal and other fuels. The major uses of
mercury are in electrical apparatus and electrolytic preparation of
chlorine and caustic soda.
The major portion (63 percent) of these emissions is land-destined
waste, followed by air emissions (31 percent) and waterborne effluents
(6 percent). The release of mercury from natural sources to air and
water is double the man-related losses to these media.
The ambient concentration of mercury in urban air is in the range
of 2 to 60 nanograms per cubic meter. Higher levels are observed near
mercury mines and geothermal steam fields, in the plumes from power plants
and incinerators, and in the environs of sewage treatment plants. Indoor
air concentrations can also be elevated in laboratories and dental offices
where mercury is used.
The natural background level of mercury in surface and underground
water is below 0.5 ppb. In areas of mercury mineralization and in some
industrialized areas, values up to a few ppb are observed. The concen-
trations of mercury in sediments reflect industrial inputs and are on
the order of parts per million. The highest levels are found near the
sediment surface.
In U.S. drinking water, mercury levels are normally less than 2 ppb.
Mercury concentrations in sludge resulting from the treatment of
wastewater are of the order of a few ppm, and the variability among U.S.
cities is not great. Thus, in agricultural applications of sludge,
mercury has not been a great concern.
In U.S. soils not disturbed by man mercury concentrations approxi-
mate those found in rocks, 0.02 to 0.4 ppm. Higher levels are found in
urban areas than in the surrounding suburbs. The mercury content of golf
xi
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course soils can be up to several hundred ppm because of the use of
mercurial fungicides. Croplands do not appear to have elevated mercury
levels.
The levels of mercury occurring in birds and mammals are quite
variable, depending on food habits and environmental conditions. Levels
may vary in or between regions because of different amounts of naturally
occurring mercury in the environment, its mobility in the environment,
and the amounts artificially introduced. Herbivorous animals tend to
have lower levels of mercury than omnivorous or carnivorous species.
Granivorous species with access to mercury-coated seeds have elevated
levels. Predators associated with wetlands or aquatic habitats usually
have the highest mercury levels. Mercury appears to concentrate in the
liver and hair or feathers.
Levels of mercury in the tissues of aquatic biota appear to be
consistently highest in industrialized Atlantic coastal environs—both
freshwater and marine. Regionally high values also occur in the states
of the Pacific Northwest, because of both mining activity and the
leaching of soils naturally high in mercury content. Other generally
isolated incidences of contamination occur in many states of the U.S.
These levels are most often associated with a point source of mercury
emission, such as sewage treatment and chlor-alkali plants, or nonpoint
source runoff from agricultural or other use of mercurial fungicides.
The highest accumulations occur in fishes at the top of the trophic
structure, the sport fishes and piscivores.
The behavior of mercury in the environment is complex due to its
existence in three oxidation states and the fact that it reacts to form
literally hundreds of compounds, both organic and inorganic. The
residence times for mercury in the four compartments of the environment
are: land, 1,000 years; atmosphere, 60 days; ocean, 320,000 years; and
sediments 2.5 x 10 years. The terrestrial system retains approximately
50 percent of the total mercury it receives, and the remainder reaches
the aquatic system through runoff and leaching. Most of the mercury
reaching the soil is confined to the top 3 cm. About 1 percent is taken
up by plants. The majority of all forms of mercury in water accumulate
finally in bottom sediment, where they may be taken up by bottom
feeders and enter the food chain. Methylmercury is synthesized in the
environment by both biological and chemical processes and is the
predominant form found in aquatic organisms.
The Food and Drug Administration's Total Diet Studies have provided
continuous monitoring of mercury levels in foods since 1971. Of the 12
food groups examined in this program, only the meat, fish, and poultry
composite has regularly contained measurable amounts of mercury. The 11
remaining food groups have generally contained less than 0.01 ppm
mercury. "Market-basket"-type surveys in which a great variety of foods
are examined indicate that mercury concentrations in foods other than
meats, fish, and poultry products are very low or nondetectable.
XII
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Estimates of daily dietary intake of mercury obtained from FDA's
Total Diet Studies for the years 1971-1974 were constant, averaging about
3 yg/day over the 4-year period.
Mercury levels in tissues of both normal and exposed humans show
considerable variation. Data from localized studies suggest "normal"
mercury levels of 0.005 ppm in whole blood, 10 ppm in hair, below 1 to 3
ppm in kidney, and below 0.75 ppm in liver. Higher levels are reported
in chlor-alkali industry workers, in dentists, in people from areas with
natural mercury deposits, and in urban populations as compared with the
rural.
Biological half-lives vary considerably depending upon the chemical
form of the mercury and also according to whether the half-life is based
upon the whole body or single organs or tissues. Inorganic forms have
the shortest half-life, probably because of their relatively poor
absorption and because their attachment to the plasma proteins of the
blood (rather than the erythrocytes) permits rapid excretion from the
body by the urine. The biological half-life of inorganic mercury in
blood has been estimated at 20 days, while for the whole body, about 40
days seems appropriate. In comparison, vapor and alkylmercurials are
more efficiently absorbed and cross the blood-brain barrier, permitting
fixation and accumulation in the brain tissue. Tracer studies of human
volunteers following inhalation of radioactiver mercury vapor have
revealed a whole-body half-life of about 58 days.
Biological half-lives in kidney and brain are substantially longer
than those for the whole body for all forms of mercury. Evidence from
primate studies suggests that the half-life of mercury in the brain is
probably on the order of years.
The whole-body half-life of methylmercury in man is about 70 to 80
days. Tracer studies, calculations from decay curves following the
elimination of methylmercury from the diet, and similar calculations
based on the distribution of mercury in hair of poisoned individuals
confirm this range.
Absorption of methylmercury from the gastrointestinal tract is
almost 100 percent complete. In addition, efficient mechanisms of
transport across the blood-brain barrier, affinity of alkylmercurials
for neurological tissue and a long half-life permit accumulations in
the brain when intake of mercury is chronic. In view of the mechanism
of biotransformation, a potential for methylmercury contamination of
the food chain exists whenever mercury is discharged into food-producing
waters.
xiii
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1. INTRODUCTION
Although mercury (Hg) is a rare element, ranking 16th from the bottom
of the list in abundance of elements in the earth's crust (Goldwater, 1971),
its unique properties have led to a number of specialized but important uses
by man. These uses, plus the natural release of mercury from ore bodies,
make mercury an ubiquitous element occurring throughout the environment (in
rocks, soil, water, and air, as well as in plant and animal tissues).
PHYSICAL AND CHEMICAL PROPERTIES
Mercury is one of the heaviest metals with a specific gravity of 13.5
compared with 11.35 for lead. It is the only metal liquid at ordinary room
temperatures, having a freezing point of -40 C (-40 F) and a boiling point
of 357 C (674 F). It has a high vapor pressure, 0.002 mm of Hg at 26 C
(79 F), so that atmospheric concentrations at ordinary room temperatures are
of concern. The most common ore of mercury is cinnabar, mercuric sulfide,
which is easily reduced by heating to liberate elemental mercury. As a
liquid, mercury is handled in flasks with the standard industrial unit for
production, consumption, and pricing statistics being a 76-pound (34.5 kg)
flask.
Mercury is found in three valence states: Hg(0), Hg(I), and Hg(II),
and forms hundreds of compounds, both inorganic and organic; the metal
reacts with a wide variety of oxidizing agents to form Hg(I) and Hg(II)
compounds and, not infrequently, mixtures of the two.
The most important mercury compounds from an environmental viewpoint
may be categorized into five groups:
(1) Metallic mercury - liquid and vapor
(2) Inorganic salts - sulfides, chlorides, nitrates, and oxides
(3) Alkyl compounds - those containing methyl or ethyl radicals
(4) Alkoxyalkyl compounds - usually complexes
(5) Aryl compounds - particularly phenymercurials.
PRODUCTION AND USES OF MERCURY
Most commercial U.S. mercury deposits are found in the far western
states, primarily in Nevada and California (Figure 1.1). Estimated U.S.
reserves represent only about 8 percent of the estimated world mercury
reserves of 180,000 tons (Cammarota, 1975). Principal producing nations
1-1
-------
I
ho
• MAZATZAL MTNS.
• DOME ROCK MTNS.
HORSE HAVEN*
BLACK BUTTE*
BONANZA*
ALTOONA
SULPHUR BANK**ABBOTT
I *REED .-i.vj
MIRABEL* •KNOXVILLE^
GREAT WESTERN* '
OAT HILL*
SONOMA (GRE'AT EASTERN MT. JACKSON)
GUAOALUPE • \
NEW ALMADEN* .NEW|DR|A
OCEANIC*
Figure 1.1. Commercial U.S. mercury deposits.
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are Algeria, Italy, Spain, Mexico, Turkey, Yugoslavia, and the USSR. The
U.S. is a net importer of mercury, and domestic primary production is
limited to a small number of mines (Smith, 1976) . The number of mines
has decreased drastically in recent years, reflecting the gradual depletion
of economically recoverable ores in the U.S. The declining importance of
U.S. primary production is illustrated in Table 1.1 which shows operating
mines and mercury production for the past several years.
TABLE 1.1. UNITED STATES DOMESTIC MERCURY PRODUCTION
1971 1972 1973 1974 1975a
Number of producing mines 56 89 24 10 3
Production, metric tons 616 253 77 75 233
Production, number of flasks 17,883 7,349 2,227 2,189 6,750
Price per flask in
New York (duty paid) $292.41 $218.28 $286.23 $281.69 $160.00
Source: U.S. Bureau of Mines, 1976.
«a
U.S. Bureau of Mines estimate.
The large Increase in 1975 resulted from the opening of a major new mine at
McDermitt, Nevada, which has an annual capacity of 20,000 flasks. Only two
other mines were in operation in 1975, and present depressed prices for
mercury make it unlikely that U.S. production will increase significantly
in the near future. It is evident from these data that losses of mercury to
the environment associated with mining and extraction have declined in
importance in recent years.
Mercury consumption, by use, is given in Table 1.2 for the 1965-1975
period. The major uses have been in electrical apparatus and electrolytic
preparation of chlorine and caustic soda (chlor-alkali). Together, these
two uses accounted for 61 percent of U.S. consumption in 1975.
The trend in mercury consumption in the U.S. has been downward since
the mid-sixties, primarily as a result of the recognition of its environ-
mental hazards. Agricultural uses have declined significantly and are
expected to continue to decline. Mercury catalysts are used in the produc-
tion of several plastics and synthetics; alternatives include organotins.
Use in dental preparations, electrical apparatus, and paints is expected to
increase with increasing population and Gross National Product (GNP). Use
1-3
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TABLE 1.2. CONSUMPTION OF MERCURY IN THE UNITED STATES
(in number of flasks)
End Use
Agriculture
Amalgamation
Catalysts
Dental preparations
Electrical apparatus
Electrolytic prepara-
tion of chlorine and
caustic soda
General laboratory
use
Industrial and
control instruments
Paint: antifouling
Paint : mildew-
proofing
Paper and pulp
manufacture
Pharmaceuticals
Other
Total, Flasks
Metric Tons
1965
3,116
268
924
3,196
18,887
8,753
2,332
10,330
255
8,211
619
418
16,251
73,560
2,538
1966
2,374
248
1,932
2,133
17,638
11,541
2,217
7,294
140
8,789
612
232
16,359
71,509
2,467
1967
3,732
219
2,489
2,386
16,223
14,306
1,940
7,459
152
7,026
446
283
12,856
69,517
2,398
1968
3,430
267
1,914
3,079
19,630
17,453
1,989
7,978
392
10,174
417
424
8,275
75,422
2,602
1969
2,689
195
2,958
2,880
18,490
20,720
1,936
6,655
244
9,486
558
712
9,134
77,372
2,669
1970
1,811
219
2,238
2,286
15,952
15,011
1,806
4,832
198
10,149
226
690
6,085
61,503
2,122
1971
1,477
1,012
2,361
16,885
12,154
1,798
4,871
414
8,191
2
682
2,410
52,257
1,803
1972
1,836
800
2,983
15,553
11,519
594
6,541
32
8,190
1
578
4,280
52,907
1,825
1973
1,830
673
2,679
18,000
13,070
658
7,155
32
7,571
606
2,009
54,283
1,872
1974
980
1,298
3,024
19,678
16,897
476
6,202
6,807
597
3,514
59,479
2,052
1975a
600
689
1,773
16,235
15,223
278
4,102
6,926
431
1,735
51,105
1,763
Sources: Van Horn (1975); Cammarota (1975)
Preliminary.
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in chlor-alkali cells may remain essentially around present levels on a
replacement basis for consumption in present cells. Chlor-alkali production
capacity expansion is estimated to be more likely via diaphragm cells than
mercury cells.
The downward trend in total mercury consumption is not expected to
continue. Projected consumption for 1985 has been estimated by the U.S.
Bureau of Mines, as reported by Van Horn (1975) and shown in Figure 1.2.
High and low ranges are by the Bureau of Mines; superimposed are "most pro-
bable" estimates by Van Horn. The U.S. Bureau of Mines (Cammarota, 1975)
subsequently estimated projected consumption for the year 2000 broken down
into six principal use categories, as shown in Figure 1.3. This projection
modifies some of the 1985 estimates. Use in electrical apparatus, primarily
batteries and mercury lamps, is estimated to increase to probably 25,000
flasks/year, and perhaps as much as 30,000. At the same time, estimates
of mercury usage in instruments and in paints have been reduced. Use in
instruments is estimated to range between 4,000 and 9,000 flasks. Use in
paints is projected to range between zero and 11,000 flasks, depending on
the extent of control or prohibition of this use. Either demands for
"other" uses remain about the same, but others now include Pharmaceuticals,
catalysts, and agricultural uses. Total use is estimated to range between
39,000 and 82,000 flasks, with the most probable value around 58,000 flasks.
This is nearly the same as Van Horn's most probable estimate of about 61,000
flasks for 1985 and very close to the average annual consumption for the
years 1970 through 1975 (55,000 flasks).
SOURCES OF ENVIRONMENTAL CONTAMINATION
BY MERCURY
Mercury may enter the environment by a variety of routes: through
man's use of the metal in chlor-alkali production, in electrical equipment,
and in mildewicides and fungicides, etc.; through the combustion of fossil
fuels and the smelting of nonferrous metals; and from natural sources such
as ore deposits and geothermal steam fields. Release to the atmosphere
around ore deposits occurs because of the volatility of mercury.
Estimates of 1973 mercury losses, tabulated according to Standard
Industrial Classification (SIC) grouping have been published by the U.S.
Environmental Protection Agency (Van Horn, 1975) and are reproduced in
Table 1.3.
In 1973, the total man-related losses in the U.S. were an estimated
1,525 metric tons, of which 31 percent was lost to the atmosphere, 6 percent
to water, and 63 percent to land. Comparable amounts, 1,200 metric tons,
were released to the environment from natural sources (85 percent to the
atmosphere and 15 percent to water). The release of mercury from natural
sources to air and water was double the man-related losses to these media.
Losses through the combustion of fuel may be higher than those shown
in this estimate. According to Spittler (1976), experience is pointing to
1-5
-------
Low
I I High
I
Most Probable
Agriculture
Catalysts for
plastics
Dental
preparations
Electrical
Chlor- Alkali
Instruments
Paints
Pharmaceuticals
Other (including
laboratory use
Itl
^^^
lysyssss^
WWWW
flffift.
1
W/M
WM<
,
y#m<
WM,
yffi.
,
^v^^Ov^vv*
rfww.
\
,
I
1
2.5 5.0 7.5 10.0 12.5
Thousands of Flasks
15.0 17.5
20.0
Figure 1.2. Projected mercury consumption in the United States
by end use, 1985 (Van Horn, 1975).
1-6
-------
Low
I I High
I
Most Probable
Caustic soda
and chlorine
Dental supplies
Electrical
Instruments
Paints
Other
ssssssss^^
I
10 20
Thousands of flasks
30
Figure 1.3. Projected mercury consumption in the United States
by end use, Year 2000 (Cammarota, 1975).
1-7
-------
TABLE 1.3. TOTAL MERCURY LOSSES IN 1973 FOR CONTERMINOUS U.S. BY SECTOR AND SIC CATEGORY
(in thousands of kilograms)
i
00
Sector
I
II
III
SIC No.
1092M
1092P
1021
1031
3331
3333
3241
3274
3332
021
2911C
2911M
2951C
3312M
4091C
49110
4924C
Description
Mercury Mining and Smelting
Mercury mining
Mercury processing
(including secondary)
Subtotals
Other Mining
Copper mining
Zinc and lead mining
Copper smelting
Zinc smelting
Cement processing
Lime processing
Lead smelting
Subtotals
Unregulated Sources
Livestock
Fuel oil-residential, commercial,
commercial, industrial
Refineries
Tars and asphalt
Coke ovens
Coal-residential, commercial,
industrial
Utilities-oil and natural gas
Natural gas-residential,
commercial, industrial
Total
Air
0.01
7.84
7.85
(1.7%)
0.02
0.00
40.77
4.59
0.50
0.08
4.75
50.71
(10.8%)
0.00
16.94
1.15
1.10
7.16
9.97
11.99
15.46
Losses to
Water
0.00
0.00
0.00
(0.0%)
0.01
0.00
2.26
0.25
0.25
0.04
0.26
3.07
(3.5%)
0.0
0.00
0.00
1.67
0.51
0.00
0.00
0.00
Land
0.01
0.41
0.42
(0.0%)
0.08
0.01
2.26
0.25
1.76
0.29
0.26
4.91
(0.5%)
17.70
0.02
1.15
14.99
2.56
1.11
0.01
0.01
Total
Mercury
Lost
0.02
8.25
8.27
(0.5%)
0.11
0.01
45.29
5.09
2.51
0.41
5.27
58.09
(3.8%)
17.70
16.96
2.30
17.76
10.23
11.08
12.00
15.47
Total
Recycled
0.00
0.00
0.00
(0.0%)
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
(0.0%)
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
-------
TABLE 1.3 (Continued)
Total Losses
Sector
III
V
VIIIA
SIC No.
4911C
2.5B
2819M
285 1M
2879M
2833M
2812
2261
2851F
38291M
3079P
3.0
3629M
36410M
36420M
2.5A
2879N
2879A
38291C
36292C
2641C
Description
Unregulated Sources (Cont'd)
Utilities-coal
Subtotals
Manufacturing and Processing
Caustic
Catalyst manufacture
Paint manufacture
Pesticide manufacture
Pharmaceuticals manufacture
Chlor-alkali
Textiles
Paint formulation
Control instrument manufacture
Catalyst usage
Other
Tubes /switches manufacture
Lamp manufacture
Battery manufacture
Subtotals
Final Consumption: Commercial
and Industrial
Urethane and miscellaneous
Nonagricultural pesticide use
Agricultural pesticide use
Control instrument consumption
Tubes/switches consumption
Lamp consumption
Air
40.71
104.48
(22.2%)
0.00
0.00
0.01
0.00
0.00
14.84
0.00
0.29
0.00
0.05
10.28
0.00
0.40
0.13
26.00
(5.5%)
0.12
4.39
0.00
16.54
7.53
6.07
Water
0.00
2.18
(2.5%)
7.61
0.02
0.20
0.06
0.02
2.93
0.15
0.35
0.00
0.10
10.23
0.00
0.00
0.05
21.72
(24.8%)
0.00
17.56
2.83
0.00
0.00
0.00
to
Land
4.52
42.07
(4.4%)
1.90
0.00
0.05
0.00
0.00
226.83
7.63
0.00
1.97
18.85
8.70
1.57
1.34
2.49
271.33
(28.1%)
2.22
21.95
16.02
107.50
46.26
37.31
Total
Mercury
Lost
45.23
148.73
(9.8%)
9.51
0.02
0.26
0.06
0.02
224.60
7.78
0.64
1.97
19.00
29.21
1.57
1.74
2.67
319.05
(21.0%)
2.34
43.90
18.85
124.04
53.79
43.38
Total
Recycled
0.00
0.00
(0.00%)
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.97
0.00
20.66
0.00
0.00
0.00
20.66
(14.1%)
0.00
0.00
0.00
82.69
0.00
0.00
-------
TABLE 1.3 (Continued)
i
c
Total Losses to
Sector SIC No.
VIIIA
7391
VIIIB
2834C
2851C
36420C
8021
Total
Final Disposal
Sewage
Urban runoff
Natural Sources
Degassing
Description
Final Consumption: Commercial
and Industrial (Cont'd)
Laboratory usage
Subtotals
Final Consumption: Consumer Goods
Pharmaceuticals consumption
Paint consumption
Battery consumption
Dental applications
Subtotals
1,
Runoff and groundwater
Air
2.28
36.93
(7.8%)
1.07
173.61
69.71
0.93
245.29
(52.0%)
4ZL.J_6,
4.01
0.00
018.70
0.00
Water
5.92
26.31
(30.0%)
17 .77
0.00
0.00
16.65
34.42
(39.2%)
&LJH
19.92
11.70
0.00
188.30
Land
1.59
232.85
(24.1%)
2.09
9.14
403.30
0.00
414.53
(42.9%)
SJiiuJLl
22.88
0.00
0.00
0.00
Total
Mercury
Lost
9.79
296.09
(19.4%)
20.90
182.75
473.01
17.58
694.24
(45.5%)
1.525.07
46.80
11.70
1,018.70
188.30
Total
Recycled
12.98
95.67
(65.2%)
0.00
0.00
24.89
5.55
30.44
(20.7%)
14JL 77
Source: Van Horn, 1975. Further refinements (as yet unpublished) have been made in these data,
but the changes are small, ±5 percent.
-------
combustion processes (coal and municipal or industrial wastes) as a chief
source of ambient mercury. In a discussion of fossil fuels as a source of
mercury pollution, Joensuu (1971) pointed out that, although the concentra-
tion of mercury in fuels is small, fuels are consumed at an enormous rate,
consequently, they must be considered as a possible significant source of
mercury released into the environment.
Joensuu presented analyses for 36 American coals. Mercury concentra-
tions ranged from 0.07 to 0.08 ppm in some West Virginia coals to 20 to 30
ppm in other West Virginia and Wyoming coals. Average of a large number of
Illinois coals was reported as 0.21 ppm (Ruch et al., 1971). If the nominal
average for coals burned in th.e U.S. is assumed to be 0.5 ppm, the average
annual consumption of 545 million metric tons (600 million tons) may release
up to 270 metric tons (300 tons) of mercury to the environment.
The available data indicate that almost all of the contained mercury
will be emitted to the air. Billings et al. (1973) determined a mercury
material balance on a large pulverized coal-fired utility boiler, finding
that over 95 percent of the mercury in the coal (0.3 ppm average) was
emitted into the flue gases. Similar results were obtained by Klein and
Andren (1975) in their investigation of the Allen Steam Plant of the
Tennessee Valley Authority and by Anderson and Smith (1977) on the basis
of a year's observations of an Illinois power plant. Thus, mercury input
to the environment from the combustion of coal is an important source of
ambient mercury.
Trends in relative mercury losses to the environment have been project-
ed by Van Horn (1975), as illustrated in Figure 1.4. Discharges to water
have already decreased significantly and this trend will continue. Dis-
charges to air have increased somewhat. This is due primarily to the
increased use of fossil fuels with higher mercury content, and this is
expected to continue to increase. Industrial discharges to land have
increased sharply, as the land has become the recipient of much of the
material previously discharged to water.
The resulting trends in the observed concentrations of mercury in the
various environmental media are not so easily deduced. This is due not only
to deficiencies in available data but also to the fact that mercury emissions
from natural sources are comparable to man-related emissions. Natural emis-
sions to air and water are double the man-related discharges to these media
and could mask small changes resulting from man's activities.
1-11
-------
ra
SI
u
•
u
-------
2. MERCURY LEVELS IN THE ENVIRONMENT
AIR
National Atmospheric Monitoring Programs
Concentrations of mercury in the atmosphere have not been measured on
a national basis. Mercury concentrations are not included in National Air
Surveillance Networks (NASN) reports, nor were data found in the U.S.
Environmental Protection Agency Storage and Retrieval of Aerometric Data
(SAROAD) computer file. The apparent reason for this omission is that
although atmospheric mercury may be largely associated with particulate
matter, some may be present as vapor. Additionally, the high ventilation
rates associated with the collector of a Hi-Vol particulate sample may
rerelease trapped mercury back to the atmosphere. Although atmospheric
mercury concentrations based on Hi-Vol sampling have been reported, they
are of dubious value (Spittler, 1976). Such results would appear to be
biased on the low side.
Approximate ranges of mercury vapor concentrations in ambient air
drawn from Goldwater's (1971) overview paper were summarized by Cooper
et al. (1974) as follows:
Mercury Concentration,
Type Location ng/m3
Outdoor Background 1-5
Urban 2-60
Indoor Indoor 100 - 200
Laboratory 200 - 10,000
Dental office 10,000 - 100,000
While not national averages, these appear to well represent the results
from a variety of localized investigations.
The explanation for the concentrations found in places which use
metallic mercury (laboratories and dental offices) is the high vapor
pressure of mercury. The vapor pressure increases rapidly with temperature,
approximately doubling for every 10 C increase. The theoretical saturation
concentrations of mercury in air have been calculated by Stahl (1969) . As
illustrated by Figure 2.1, at normal ambient temperatures these are in the
range of 5 to 20 milligrams per cubic meter. While saturation is an unlikely
concentration, these values are illustrative of the possibilities of reaching
2-1
-------
12 16 20 24 28 32
Temperature, C
36 40
44
Figure 2.1. Theoretical saturation concentrations of
mercury in air (Stahl, 1969).
2-2
-------
elevated concentrations in unventilated rooms which are contaminated with
mercury.
Local Monitoring of Atmospheric
Mercury Concentrations
Although there have been a few localized monitoring efforts in the
1970's there is still a paucity of data.
Sampling and analytical methods and procedures have contributed to
the lack of reliable data on mercury concentrations in air. As noted in
the preceding section, some of the local investigations have been based
on the analysis of Hi-Vol particulate samples.
Some investigators absorbed mercury from the air in iodine monochloride
(IC1) solutions, an EPA standard method. The initial version of the method
was found to give both imprecise and inaccurate results (Mitchell and Midgett,
1976) . The method has been modified and improved by these same investigators
to give satisfactory results; however, the reliability of earlier results
obtained by this method may be suspect.
The preferred method for detecting mercury concentrations in air at
the nanogram per cubic meter level now appears to be based on the trapping
of mercury as an amalgam on silver wool or on a gold screen. The use of
two duplicate air streams permits the collection of elemental mercury on
silver wool in one side; a pyrolyzer converts mercury compounds in the
other stream to elemental mercury, which is also collected on silver wool.
This method provides data on both elemental and total mercury (Spittler,
1976). The analytical method now generally used is based on revolatiliza-
tion of the collected mercury sample and passage through a gas optical cell
in a flameless atomic absorption spectrometer.
Soldano et al. (1974, 1975) described the results of a survey of
airborne mercury concentrations in the environs of sewage treatment plants,
using an adaptation of mercury speciation technique described by Braman et
al. (1974). This technique involves the stacking of four different materials
to collect different forms of mercury:
Acid Chromosorb W - Inorganic mercury compounds
Basic Chromosorb W - Alkyl mercury halides
Silvered sand - Elemental mercury
Gold-coated sand - Dialkyl forms of mercury
Results were presented for a number of cities (Table 2.1). Large differences
in mercury concentration were found among the different cities and among
samples obtained within the same city. The results ranee from a low of
0.13 ng/m3 in a Utica, New York, sample to 600,000 ng/m3 in a Memphis,
Tennessee, sample. Factors such as weather conditions, distance from the
sewage plant, and elevation of the collection point are cited as factors
influencing the results within a city. All forms of mercury were found;
2-3
-------
TABLE 2.1. A COMPARISON OF MERCURY CONCENTRATIONS IN THE
AIR AS A FUNCTION OF SPECIES AND LOCATION
Concentration, ng/m
Sample Location
Richmond (I)
Richmond (I)
Richmond (II)
Richmond (II)
Richmond (II)
Richmond (II)
Richmond (II)
TVA (Bull Run)
Oak Ridge TN
Knoxville TN
Knoxville TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Memphis TN
Greenville SC
Greenville SC
Greenville SC
Greenville SC
Greenville SC
Utica NY
Utica NY
Utica NY
Utica NY
Louisville KY
Louisville KY
Louisville KY
Louisville KY
Louisville KY
Set
No.
2
4
1
2
3
4
5
1
1
1
2
1
2
23
24
25
26
27
28
29
30
32
33
36
37
38
39
1
2
2
3
4
2
4
5
6
13
14
15
16
19
Acidic
(Inorganic-
Mercury)'3
20
2.13
0.25
0.88
0.78
1.25
2.50
0.43
1.98
3.75
1.30
210
1,428
2,930
2,090
1,667
1,237
2,875
4,225
140
3,250
186
275
3,280
15,875
3,750
3,800
0.12
7.75C
1.23
11.25
0.30
—
0.15
0.36
0.21
410
1,470
2,093
1,105
6,250
Basic
(Alkyl Mercury
Halides)b
62.50
8,750
0.53
0.50
9.50
0.85
0.83
1.38
107.50
21.75
2,262
9,525
1,050
4,180
3,800
7,625
33,250
2,625
130
3,730
383
198
8,580
1,032
6,250
19,000
0.68
—
—
67.50
6.50
0.13
3.25
0.80
0.95
308
2.950
9,300
13,159
42,500
Silver
(Elemental
Mercury)^
2.50
—
1.60
1.80
0.80
6.80
1.80
0.53
1.58
1.75
0.35
380
42,800
1,360
23,300
3,330
16.7
5,500
10,000
240
932
488
1,333
17,100
15,950
600,000
1,357
0.08
—
21.25
0.58
225
—
0.20
0.60
0.33
718
1,410
1,395
2,625
550
Gold
(Dialkyl
Forms)'3
__
—
—
—
—
—
0.50
0.33
2.75
4
0.55
285
4,750
3,330
13,950
1,380
285
3,700
4,530
210
605
465
4,780
515
6,975
10,000
452
1.50
1.55
3.50
25
—
3.50
—
1.68
410
15,300
465
1,262
2,375
Source: Soldano et al. (1974, 1975).
All are in the environs of sewage treatment plants except TVA which is a
coal-fired steam plant.
Positive identifications of the mercury forms were not made but were
inferred from the collected fractions.
Interference.
2-4
-------
and the authors indicate that the mercury concentration-distance dependency
varies with the mercury form, a less volatile form (elemental mercury)
declining in concentration with increasing distance from the plant, and the
form collected in the basic fraction (highly volatile alkyl mercury halides)
increasing in concentration with increasing distance. The results are
compared with the lower concentrations obtained near a TVA coal-fired steam
plant at Bull Run, and the conclusion is drawn that the results provide
evidence for mercury and organic mercury pollution of the air that can be
attributed to municipal sewage treatment facilities. The sewage treatment
facilities may constitute a means of concentrating elemental mercury and
reemitting it, in combination with the organic products characteristic of
sewage systems, into the air (Soldano et al., 1975). The authors correlate
their maximum observed organic mercury concentrations with the population
load on the sewage facility, Oak Ridge and Utica being the smallest and
Memphis the largest.
The largest variety and number of recent analyses are those generated
by Spittler (1976). In the first set of analyses of locations in North
Carolina sampled in 1972, the double-air-stream instrument was used,
permitting analysis for both elemental and total mercury. Results for
three cities are shown in 'Table 2.2. The total mercury concentrations in
the three cities ranged from 4 to 8 ng/m3.
TABLE 2.2. ELEMENTAL AND TOTAL ATMOSPHERIC MERCURY CONCENTRATIONS
IN THREE NORTH CAROLINA CITIES
Concentration, ng/m"
Date
1972 Location
October 3 Gary NC
4
5
6-8
October 3 Durham NC
4
5
6-7
October 3 Raleigh NC
4
5
6-9
Total
6.0
6.9
8.1
7.7
3.8
4.3
6.9
5.3
5.7
6.4
5.9
4.2
Elemental
6.0
6.8
6.1
5.7
4.7
4.4
4.8
3.5
6.0
6.8
5.8
4.1
Total Minus
Elemental
0.0
0.1
2.0
2.0
-0.9
-0.1
2.1
1.8
-0.3
-0.4
0.1
0.1
Source: Spittler, 1976.
2-5
-------
In Spittier's opinion, most airborne mercury will be found to be in
the elemental form unless some very special problem is known to exist or a
specific industrial source is under investigation. In conformance with
this conclusion (which appears to be in harmony with the data in Table 2.2),
only elemental mercury was measured in subsequent analyses conducted in
1975 and 1976.
During 1975 and 1976 mercury analyses were conducted on a variety of
samples mostly from Massachusetts, Connecticut, Rhode Island, Vermont, and
Maine, with a scattering of other samples from Indiana, Ohio, Illinois, and
Florida. Results of these analyses are presented in Table 2.3. Over 90
percent of the samples yielded mercury concentrations in the range of 2 to
60 ng/m3, the ambient urban air concentration reported by Goldwater (1971)
and Cooper et al. (1974). The most significant exceptions were a level of
5,820 ng/m3 in a power plant plume in Fall River, Massachusetts, a level of
275 ng/m3 in the plume from a burning dump in Middleton, Massachusetts, and
200 ng/m in an incinerator plume in Marlboro, Massachusetts. Several
samples were obtained in airports, but they did not yield results any higher
than ambient levels.
A number of urban atmospheres were sampled by Cooper et al. (1974)
using a gold-screen collector. Results are summarized in Table 2.4. The
two highest concentrations, El Paso, Texas, and Kellogg, Idaho, were from
samples taken near nonferrous smelting operations. Other samples ranged
between 5.0 and 14.4 ng/m3. In this same study, automobile exhaust gases
were sampled and found to contain between 95 and 160 ng/m3; the fuel was
not analyzed. These data suggest that transportation sources may be
significant sources of mercury emission due to the mercury content of
petroleum. This conclusion is supported by near-highway measurements by
Cooper et al., which showed mercury concentrations from ca. 5 ng/m3 during
low-traffic hours to 10 to 12 ng/m3 during peak traffic hours.
A series of duplicate samples taken during 1973 in Chicago (Wroblewski
et al., 1974) at nine sites, using a silver-wool collector, showed average
mercury concentrations to range from 10 to 38 ng/m ; the average for all
sites was 22 ng/m3- Individual samples ranged from 5 to 60 ng/m , and in
most instances, duplicate samples agreed within 20 percent.
In contrast to the above values, monthly composites of Hi-Vol filter
samples collected during September-November, 1971, averaged only from 3.8
to 4.1 ng/m3. These data were considered to be evidence that either only
a portion of the mercury was associated with particulates or losses were
occurring during the collection of Hi-Vol samples.
Jepsen (1973) reported a series of measurements of atmospheric mercury
concentrations in California, a state with a large fraction of the U.S.
deposits or mercury ores, as well as a large portion of U.S. geothermal
steam fields. He used a portable Barringer airborne mercury spectrometer
(BAMS) and sampled by bus, car, helicopter, and boat, utilizing traverses
to locate, quantify, and map anomalous mercury plumes. Several previously
unreported sit^s of mercury contamination associated with natural sources,
such as mercury mines and hot springs areas, and cultural sources such as
2-6
-------
TABLE 2.3. SUMMARY OF ATMOSPHERIC MERCURY MEASUREMENTS
AT SELECTED U.S. LOCATIONS
Location
Connecticut
Groton
Hamben
Hartford
Suburbs
Middleton
New Haven
Georgia
Atlanta, airport
Illinois
Chicago
Wheaton
Indiana
Indianapolis
Indianapolis , airport
Maine
Allagash River Basin
Concentration , a
Date Time ng/m3
Aug. 5, 1975 49
Aug. 7, 1975 107
April 11, 1976 20
13
Aug. 7, 1975 29
14
Nov. 10, 1975 3.5
Oct. 4, 1975 7.0
Oct. 3, 1975 1.9 (2.4)
Oct. 5, 1975 4.4 (4.9)
Oct. 6, 1975 17.7 (19.4)
5.4 (8.4)
Oct. 7, 1975 33.2
Sept. 8, 1975 33
4.6
8
36
43
Nov. 3, 1975 12
20
8
16
15
4.3
11
9
Dec. 16, 1975 3
30
39
8
13
11
8.6
12
2-7
-------
TABLE 2.3. (Continued)
Location
Massachusetts
Boston
Airport, inside
JFK parking lot
Over harbor, in plane
Ditto
Fall River, in power plant
plume
Framingham
In incinerator plume
Lexington
Marlboro
Incinerator, across street
Incinerator, in plume
Incinerator, 320 m downwind
Middleton
In plume from burning dump
90 m downwind of dump
1.6 km downwind of dump
3.2 km downwind of dump
8.0 km downwind of dump
Milton
Needham
Norwood, airport
Walpole
Date
Feb. 27, 1976
Nov. 10, 1975
Dec. 10, 1975
Aug. 15, 1975
Ditto
Dec. 9, 1975
Aug. 8, 1975
May 10, 1976
Aug. 5, 1975
-
April 11, 1976
Ditto
II
Nov. 28, 1975
Ditto
it
n
11
Aug. 21, 1975
Aug. 22, 1975
Ditto
Aug. 26, 1975
Ditto
Aug. 27, 1975
Ditto
Aug. 28, 1975
Aug. 6, 1975
Sept. 3, 1975
Nov. 28, 1975
Aug. 6, 1975
Concentration,3
Time ng/m^
0700-1000
1000-1200
1530-1730
0800-1000
1000-1200
0900-1200
1200-1500
0800-1100
1100-1500
0800-1200
12
13
20
9 (14)
5.4 (7.
5820
5.5
42
9.8 (10
16 (20)
17 (13)
3.6 (3.
20.7
7.1 (8.
22.5
19.2
4 (6)
3 (4)
11 (12)
88
200
26
275
45
25
12.5
10
25
16.5
14.6
13.5
5.2
8.0
7.5
53
9.6 (10
4 (4)
15
10 (7.5)
3)
.3)
8)
6)
.6)
2-8
-------
TABLE 2.3. (Continued)
Location
Date
Time
Concentration,a
ng/m3
Ohio
Cleveland, airport
Dayton, airport
Parma
Rhode Island
Providence
Vermont
Burlington
Rutland
Oct
Aug
Aug
Oct
Oct
. 7, 1975
. 5, 1975
. 13, 1975
. 16, 1975
Ditto
ii
. 17, 1975
6.9
18.7
4.9
105
62 (55)
1400-1500 7.5
1600-1700 17
2000-2300 3.3
0930-1200 20
Source: Spittler, 1976.
values in parentheses are replicates.
2-9
-------
TABLE 2.4. AMBIENT OUTDOOR MERCURY CONCENTRATIONS
IN SELECTED U.S. CITIES
City
El Paso TX
Kellogg ID
Oakland CA
Chicago IL
Memphis TN
Berkely CA
San Francisco CA
Tucson AZ
Seattle WA
Louisville KY
Nashville TN
Time of Sample
Collection
0945
1530
1140
1320
1040
1040
1745
1710
1805
1335
1655
Concentration ,
ng Hg/m3 air
29.6
21.5
14.4
13.0
11.8
10.5
10.3
9.5
8.6
5.9
5.0
Sample
Location
Industrial
Industrial
Freeway
Hospital
Industrial
Commercial
Freeway
Freeway
Residential
Commercial
Freeway
Source: Cooper et al., 1974.
chlor-alkali and other chemical plants, sewage treatment plants, and
sanitary landfills were identified. By far the largest mercury concen-
tration was detected in a steam vent at the Geysers, as shown by Table
2.5, which highlights the anomalies from the reconnaissance program,
which covered over 30,000 km2. Other natural sources with higher-than-
average concentrations were near the New Almaden mercury mine, as well as
in the Clear Lake area, near the still-active Abbott mine, and the closed
Sulfur Bank mine. However, most of the measurements were at normal ambient
levels, in the range from 0 to 10 or 15 ng/m3, comparable to levels in other
states.
Measurements of mercury scrubbed from the air by rainfall have been
made by several investigators. In one of the most recent studies,
Schlesinger et al. (1974) measured mercury and lead deposited by rainfall
in an isolated area on the western slope of a New Hampshire mountain at
elevations ranging from 486 to 1,372 m (1,590 to 4,500 ft). During the
period June 30 to November 7, 1971, the collected precipitation averaged
0.06 ppb mercury, and the mean deposition was calculated to be 0.23 ng/m2
day.
WATER AND SEDIMENTS
National Monitoring Program
Data on mercury in water are reported for two forms: dissolved and
total. Dissolved mercury is determined on filtered (0.45 micron membrane)
samples, and provides an indication of what might occur in a treated or
2-10
-------
TABLE 2.5. SUMMARY OF CALIFORNIA ATMOSPHERIC MERCURY MEASUREMENTS
Site
Natural Sources
Abbott Mine
Clear Lake
The Geysers
New Almaden
Cultural Sources
Berkeley
Oakland-
Emeryville
Pittsburgh
San Francisco
Richmond
Date3
Feb. 12
Feb. 12
April 2
Feb. 15
Jan. 4
March 24
March 22
March 24
March 26
March 30
March 30
April 5
April 6
Feb. 11
Feb. 12
Feb. 25
March 22
April 1
March 18
March 19
Jan. 19-26
April 7,8
March 29
Time
P.M.
P.M.
P.M.
P.M.
P.M.
P.M.
A.M.
A.M.
P.M.
P.M.
P.M.
P.M.
P.M.
P.M.
A.M.
A.M.
P.M.
A.M. -P.M.
P.M.
A.M.
A.M. -P.M.
A.M. -P.M.
A.M.
P.M.
Wind
E
E
W
W
W
W
W
W
NW
W
W
E
NW
N
WNW
N
NW
W
Mercury
Background
Level ,
ng/m3
0
0
0
200-800
0
5-15
10
10
0
0
0
0
50
0
0
5
0
0
0
0
0
5
5
Mercury
Peak Value,
ng/m3
470
150
200
28,100
1,500
449
800
449
154
1,050
196
668
110
700
1,000
0
10
4,141
278
152
100
35
1,400
2,000
Comments
Low population density
Resort area, low population
density
Rural resort area
Rural
Light industrial-residential
Downwind of landfill
Light industrial
Industrial complex
Downwind of STP flare
Industrial area
Industrial area
On boat
Residential
Industrial-residential
Commercial area, quicksilver
products
Ambient measurements,
financial district
Residential, near primary school
Source: Jepsen, 1973.
aDate not given, probably 1971.
-------
filtered water supply drawn from the same source. Total mercury represents
the amount in the water-sediment mixture, and is indicative of what might be
included in the food chain of the aquatic community (Durum et al., 1971).
Most of the analyses contained in this report are of total mercury.
A nationwide reconnaissance of selected minor elements in the surface
waters of the 50 states and Puerto Rico was conducted by the U.S. Geological
Survey in cooperation with the U.S. Bureau of Sport Fisheries and Wildlife
in the autumn of 1970 (Durum et al., 1971). There were three kinds of
samples:
• Benchmark stations
• Surface water sources for cities greater
than 100,000 population (or largest city
in state)
• Water courses downstream of major municipal
and/or industrial complexes.
The presence of mercury was reported in 19 percent of the 722 published
analyses (Durum, 1974). Dissolved mercury was detected (greater than 1 ppb)
in about 7 percent of the samples. In 21 samples mercury was found in both
the unfiltered sample (0.5 ppb detection limit) and the filtered (0.1 ppb
detection limit) companion sample. In about half of the waters in which
mercury was detected, a significant fraction of the mercury was being
transported in the particulate fraction (Durum, 1974) . The "benchmark"
stations were established by the Geological Survey in the mid-1950's for
purposes of measuring long-term natural trends in stream flow and water
quality. Benchmark stations are located toward the headwaters of tributary
streams in these basins, in generally undeveloped areas, and thus are
presumably fairly free from contamination. Their locations are shown in
Figure 2.2. Examination of the mercury analyses from the 49 benchmark
stations included in the summary of the reconnaissance (Durum et al., 1971)
showed that mercury was undetected in 43 (88 percent). California and
Nevada are two of the principal areas of mercury mineralization, and it
was not surprising that mercury was detected at two benchmark stations in
each state (0.8 to 6.0 ppb). Except for these, mercury was detected only
at single benchmark stations in Maine (0.6 ppb) and in Hawaii (1.2 ppb).
The Geological Survey, in an unpublished report submitted to the U.S.
House of Representatives, Committee on Merchant Marine and Fisheries
(Pickering, 1976), summarized the data in its computer storage file
(accessed up to mid-January, 1976) on six toxic substances, including
mercury. These data are also presumed to include the results of the 1970
reconnaissance. The data for mercury in surface waters (streams, lakes,
and reservoirs) and in groundwaters (wells and springs) have been extracted
from this summary and are presented in Tables 2.6 and 2.7, and summarized
in Table 2.8.
2-12
-------
N)
I
•4S 46.: :rr;
I X > I
Figure 2.2. Location of hydrologic benchmark stations
maintained by the U.S. Geological Survey.
-------
TABLE 2.6. MERCURY LEVELS IN SURFACE WATERS OF THE UNITED STATES
o
Dissolved Mercury
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
i Idaho
j^ Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
NC
94
21
23
32
99
362
34
0
50
77
14
66
82
27
9
20
96
190
11
2
18
103
30
20
14
84
63
8
6
32
23
N>0d
88
9
17
28
75
196
34
40
42
12
60
79
20
9
14
78
122
11
2
18
91
22
16
8
72
56
8
6
32
14
N>2,
Ppb
24
1
0
6
16
3
1
1
3
0
11
1
0
4
3
4
2
0
1
2
16
1
2
1
7
17
0
1
1
0
Max,e
Ppb
56
4.0
0.6
4.3
12
4.5
3.8
3.6
2.0
1.2
8.7
2.2
0.8
24
3.0
7.5
2.3
0.6
5.0
4.7
196
2.6
2.7
4.3
9.0
44
1.8
3.7
2.8
0.5
Total Mercury
NC
47
42
13
100
157
122
30
0
296
40
10
43
26
23
15
29
95
155
16
2
21
79
41
67
28
82
66
15
22
53
77
N>0d
39
34
12
81
99
44
30
230
6
8
43
24
17
15
29
87
133
16
2
21
73
30
56
21
66
60
13
22
42
51
N>0.2,
Ppb
35
25
0
72
80
16
30
193
4
3
40
23
11
12
26
78
121
16
2
21
61
21
30
16
56
53
12
22
41
32
Max,e
Ppb
0.7
2.2
32
15
12
1.8
0.7
22
1.8
0.9
8.3
3.5
0.8
1.8
10
7.9
5.0
5.5
5.0
0.7
240
10
17
4.8
11
92
25
0.7
5.9
4.0
Mercury in
Bottom Material
NC
3
0
1
13
26
48
38
0
83
11
3
1
6
6
0
1
39
188
5
1
0
1
21
53
2
5
0
0
0
10
1
N>0d
4
0
13
22
47
36
69
8
3
0
5
0
0
32
170
3
0
1
21
31
0
5
8
0
Max,e
ppm
1.7
0.0
0.5
0.3
0.1
3.7
4.0
0.6
0.1
0.0
0.1
0.0
0.0
15
9.0
0.1
0.0
1.7
0.2
37
0.0
0.2
270
0.0
-------
TABLE 2.6. (Continued)
Ln
a
Dissolved Mercury
State
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
United States
„<
74
34
72
31
20
19
61
9
11
23
19
157
78
4
4
11
52
36
60
2,515
N>0d
74
28
58
31
12
14
61
9
10
14
18
142
50
4
4
10
52
25
23
1,918
N>2,
ppb
2
0
11
1
3
0
0
0
0
0
0
37
2
1
0
1
3
1
2
193
Max,8
ppb
17
0.8
76
6.0
12
1.0
1.3
0.5
0.3
1.0
0.6
160
7.0
3.4
1.6
2.1
5.0
2.0
2.4
196
N6
360
76
70
353
27
13
184
9
11
39
58
33
37
4
4
160
50
30
66
3,396
Total Mercury
N>0d
360
51
46
353
24
11
181
9
11
26
53
30
20
4
4
142
50
20
31
2,830
N>0.2,
ppb
360
48
34
351
18
7
172
9
11
19
35
24
12
4
4
121
50
10
22
2,472
Max,8
ppb
2,800
8.8
3.3
61
15
2.5
50
0.5
0.5
1.7
110
1.6
1.3
0.5
0.6
2,700
5.0
1.2
2.1
2,800
Mercury in
Bottom Material
NC
6
18
3
1
6
4
35
0
5
0
1
3
0
0
0
1
15
13
3
650
N>0d
6
17
0
0
6
0
33
0
4
0
0
1
0
0
0
0
7
7
0
559
Max,8
ppm
0.3
0.6
0.0
0.0
0.1
0.0
70
0.5
0.0
0.2
0.0
0.1
3.0
0.0
270
Source: Pickering, 1976.
Filtered sample.
Unfiltered sample.
^ = Number of stations for which data are available.
N>0 = Number of stations with detectable mercury.
Max = Maximum value found.
-------
TABLE 2.7. MERCURY LEVELS IN GROUNDWATER OF THE UNITED STATES
Dissolved
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Florida
Georgia
Idaho
Indiana
Iowa
Kentucky
Louisiana
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
South Dakota
Tennessee
Texas
Utah
Virginia
Washington
West Virginia
Wisconsin
Wyoming
United States
NC
54
21
22
20
62
305
10
92
191
138
51
6
7
1
7
0
3
0
40
151
0
7
10
17
1
78
0
9
1
63
0
0
74
57
2
0
19
32
52
1,603
N>0d
48
7
11
7
21
77
8
68
92
77
34
6
6
1
6
0
20
67
6
7
17
0
45
1
0
63
53
29
2
19
22
17
837
•a
Mercury
N>2,
ppb
5
0
0
0
0
5
1
0
2
3
6
0
0
0
1
0
1
6
0
0
0
0
2
0
0
1
0
0
0
0
0
1
34
Max,6
ppb
10
0.6
0.2
0.4
1.0
5.3
5.0
1.7
5.6
4.3
9.8
1.0
1.4
1.4
13
0.0
2.0
13
0.5
0.7
1.0
0.0
2.4
0.1
0.0
11
1.9
1.0
0.2
0.5
0.9
2.1
13
N°
0
18
0
0
34
9
6
302
0
0
0
0
5
22
23
11
4
16
0
0
16
31
88
209
6
11
5
0
12
7
56
18
0
0
0
39
19
0
54
1,021
Total Mercury
N>0d
12
26
2
6
219
2
16
13
2
0
9
16
31
21
209
6
9
5
1
5
17
13
31
19
25
715
N>0.2,
PPb
6
18
1
6
148
1
11
8
1
0
8
15
31
8
209
5
3
5
1
5
13
5
4
19
13
544
Max,6
ppb
1.7
20
0.2
0.5
4.0
0.2
0.5
1.1
0.6
0.0
2.2
5.0
7.1
2.2
31
14
0.6
0.5
0.4
0.9
0.5
0.2
0.7
5.9
5.3
31
Source: Pickering, 1976.
o
Filtered sample.
Unfiltered sample.
CN = Number of stations for which data are available,
N>0 = Number of stations with detectable mercury.
6Max = Maximum value found.
2-16
-------
TABLE 2.8. SUMMARY OF MERCURY CONCENTRATIONS IN U.S. WATERS
Surface Waters Groundwater
Dissolved Total Dissolved Total
Number of states sampled 49 49 32 25
Number of sites sampled 2,515 3,396 1,603 1,021
Positive values
Number 1,918 2,830 837 715
Percent 76.3 69.3 52.2 70.0
Values >2 ppb
Number 193 34
Percent 7.7 2.1
Values >0.2 ppb
Number
Percent
Maximum value, ppb
2,472
72.8
196 2,800
544
53.3
13 31
Dissolved values shown are based on the analyses of water passed
through a 0.45 micrometer filter; "total" values are for unfiltered samples
containing suspended sediment. Dissolved values are compared with the 2
ppb maximum mercury level contained in the National Interim Primary Drink-
ing Water Regulations (U.S. Environmental Protection Agency, 1975a). For
"total" values the comparison is with the 0.2 ppb criterion recommended in
Water Quality Criteria 1972 for freshwater aquatic life and wildlife
(Rooney, 1973). In only 2 to 8 percent of the samples did dissolved
mercury exceed the 2 ppb limit recommended for drinking water, but in 53
to 73 percent the total mercury exceeded the more stringent 0.2 ppb water
quality criterion recommended for mercury by the National Academy of
Sciences. The Geological Survey data indicate that on the average, ground-
water quality with respect to mercury exceeds that of surface water.
Data from a separate nationwide study of mercury in waters has been
summarized by Jenne (1972). A majority of the samples analyzed contained
less than 0.5 ppb. About 17 percent had mercury contents of 1 ppb or
greater. Only 4 percent of the surface water samples contained in excess
of 10 ppb mercury. The higher mercury concentrations were generally found
in small streams. About half of the 43 samples from the Mississippi River
contained less than 0.1 ppb. The mercury content of lakes and reservoirs
was scattered between less than 0.1 and 1.8 ppb. With few exceptions, the
mercury content of qroundwater samples was below the limit of detection.
In summarizing the present status of U.S. waters, Durum (1974) stated
that on the basis of the surveys to date in which the preponderance of
2-17
-------
analyses show mercury to be below the limit of detection, the natural
background level of total mercury in surface and underground water is
certainly below 0.5 ppb, and is probably considerably lower than that.
Confirmation of this conclusion is provided by the EPA STORE! data
for 1970-1974 presented in the 6th Annual Report on Environmental Quality
(Council on Environmental Quality, 1976) shown in Figure 2.3. The range
of mercury concentrations in surface waters is from 0.04 to 0.10 ppb.
0.11—
C.06
O
•H .05
4-1
tfl .04
4J.03
§ .02
3.01
o
U 1970
1971
1972 1973
Year
1974
1975
Figure 2.3. Mercury levels in U.S. surface waters, 1970-1974
(Council on Environmental Quality, 1976).
Local Monitoring of Mercury Concentrations
Local studies of mercury concentrations in water and sediments have
been conducted in recent years in most of the major U.S. drainage basins
(see Figure 2.4). Many of these studies were conducted to investigate an
identified or suspected mercury-enrichment problem, so that averaging the
findings of the various studies can be misleading with respect to defining
average ambient concentrations. Selected localized investigations are
briefly summarized in the following paragraphs.
The North Atlantic Basin(l)* is in one of the most highly urbanized
and industrialized regions of the country, and high mercury concentrations
in water, and particularly in sediments, are possible. Illustrative are
the sediment mercury concentrations determined in Baltimore Harbor by Villa
^Numbers in parentheses refer to drainage basins identified in Figure 2.4.
2-18
-------
NJ
1
Figure 2.4. U.S. Geological Survey classification of major drainage basins
in the United States.
-------
and Johnson (1974), as shown in Figure 2.5. The distribution of mercury was
found to correlate with large industrial complexes, and concentrations of up
to 6 ppm were observed. The heaviest concentrations can be seen to be
located in the more sheltered areas away from the main channel and in the
areas of manufacturing industry or marine and commercial establishments.
Roberts et al. (1975) has compiled state data for mercury. Sediment
samples from Boston Harbor were found to have mean concentrations of 2 to 3
ppm of mercury; sediment levels were generally higher at the sediment surface,
and the highest mercury levels correlated with high organic content. In other
Massachusetts sediment samples at Taunton River and Muddy Cove, means were 2
to 36 ppm, with a range of 0.1 to 130 ppm. Unlike the usual study in which
there is no breakdown of the form of the mercury, this study also determined
methylmercury content and found that only a very small fraction, 0.1 to 0.5
percent, was in the methylmercury form.
Similarly, low fractions of methylmercury, only 0.03 to 0.07 percent
of total mercury, were found in the Everglades (Andren and Harris, 1973).
The Ohio River Basin(3) is one of the major U.S. drainage basins,
especially whth respect to the population served, and to the industrial
concentration within it. The Ohio River Valley Water Sanitation Commission
(ORSANCO) has monitored the Ohio River and its major tributaries for some
years, now including some of the heavy metals. Recent (1975-1976) mercury
results (Table 2.9) are illustrative of present levels in the Ohio River as
it passes through an industrialized area. Most of the samples are below the
limit of detection and the median value is certainly below 0.5 ppb; only
one value exceeds 1 ppb.
The St. Lawrence River Basin(4) includes the Great Lakes, in which
mercury concentrations have been studied extensively since about 1969, when
mercury contamination was discovered in fish taken in Canadian waters of
Lake St. Clair. Most of the mercury contamination was ascribed to dis-
charges from chlor-alkali plants; controls have since been instituted which
have essentially eliminated such discharges.
Chau and Saitoh (1973), in summarizing the results of a 2-year survey
of mercury concentrations in international Great Lakes waters, concluded
that the distribution of mercury is quite uniform; the mercury levels in
the majority (75 percent) of the samples fell within the 0 to 0.4 ppb range
for all lakes. The mean concentrations for 915 water samples (surface,
intermediate, and bottom) from Lakes Ontario, Erie, Huron, and Superior,
were 0.13, 0.17, 0.17, and 0.18 ppb, respectively. Chau and Saitoh classi-
fied the average mercury concentrations as low compared with those for the
lakes and reservoirs of the United States considered by Jenne (1972).
Chay and Saitoh also concluded on the basis of a comparison of their
work with others that there is no direct relationship between mercury
distributions in the water and sediments of the Great Lakes. The sediment
mercury concentrations, as a nonmobile phase, reflect closely the areas of
industrial inputs, whereas water does not. Confirmation of the correlation
of sediment concentrations and industrial inputs can be found in the study
2-20
-------
Figure 2.5. Mercury levels in Baltimore Harbor sediments.
2-21
-------
TABLE 2.9. MERCURY CONCENTRATIONS IN THE OHIO RIVER AND SOME OF ITS TRIBUTARIES
S3
Location
Illinois
Ohio River at Joppa
Indiana
Ohio River at Evansville
Ohio River at Uniontown
Kentucky
Licking River, Kenton County
Ohio River at Louisville
Ohio River at West Point
Green River at Sebree
Ohio
Ohio River at East Liverpool
Ohio River at Shady side
Muskingum River at Marietta
Ohio River at Belleville
Ohio River at Kyger Creek
Ohio River at Kenoga
Scioto River at Lucasville
Ohio River at Meldahl
Ohio River at Cincinnati
Little Miami River
Greater Miami River
Pennsylvania
Allegheny River at Oakmont
Monongahela River at St. Pittsburgh
Ohio River at South Heights
Beaver River at Beaver Falls
West Virginia
Ohio River at Pike Island
Ohio River at Willow Island
Date of Data Number of
Collection Samples
Oct. 1975-April 1976
Nov. 1975-April 1976
IT ri
n ti
Oct. 1975-April 1976
Nov. 1975-April 1976
Oct. 1975-April 1976
Sept. 1975-April 1976
II II
II It
II II
OcC. 1975-April 1976
Nov. 1975-April 1976
Oct. 1975-April 1976
II It
M II
Sept. 1975-April 1976
Oct. 1975-April 1976
Sept. 1975-April 1976
n n
ti n
n n
i n
n n
6
6
6
7
7
6
6
8
8
8
7
7
6
7
7
7
8
6
7
7
8
8
8
8
Frequency of
Detection ,
%
50
50
67
0
57
33
33
13
0
0
0
0
0
0
0
0
13
0
15
14
13
13
13
0
Range of Mercury
Concentration,
ppb
0.0-0.3
0.0-0.1
0.0-0.1
<0.5
0.0-0.2
0.0-0.1
<0.5
<0.5-0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5-1.2
<0.5
<0.5-0.5
<0.5-0.5
<0.5-0.5
<0.5-0.5
<0.5-0.5
<0.5
Source: Ohio River Valley Water Sanitation Commission, 1975, 1976.
-------
of mercury contents of sediment cores from western Lake Erie by Kovacik and
Waters (1973) . They determined that the mercury concentrations in sediments
related directly to the flow pattern of Detroit River water into the lake,
carrying mercury from chlor-alkali plants upstream. They found also that
modern sediments exhibited a surface enrichment zone of 1 to 4 ppm which
decreased exponentially with depth to the background level of 0.04 to 0.08
ppm observed below about 15 cm in most cores. Their data indicated that no
change has occurred in background levels until modern times.
Results of an unpublished EPA study (U.S. Environmental Protection
Agency, 1976a) provide additional data on the mercury contents observed in
403 sediment samples collected from harbors along the shores of the Great
Lakes between Erie, Pennsylvania, and Duluth, Minnesota. As shown in the
frequency distribution curve in Figure 2.6, over 98 percent of the samples
were below 0.7 ppm, and approximately 85 percent contained 0.2 ppm or less.
Approximately 60 percent were below the detection limit of 0.1 ppm. Only
three samples, all from the Great Lakes Naval Training Base, Illinois,
exceeded 0.7 ppm (2.0, 3.0, and 14.0 ppm).
Localized investigations in other basins provided similar patterns
of mercury distribution. The highest levels of mercury in surface waters
tended to be associated with periods of low flow, implying the effect of a
dilution factor during periods of high flow. Elevated concentrations in
sediments appeared to be related to inputs from nearby point sources.
Sediment mercury concentrations showed positive correlations with organic
content, small particle size, and sulfur content. Undisturbed sediment
cores generally exhibit a decreasing mercury content with depth. Although
methylmercury analyses are few in number, the evidence is consistent that
the fraction of total mercury present in sediments in this form is very low.
DRINKING WATER
The U.S. Public Health Service conducted one of the first broad-based
investigations of drinking water quality in 1969. The study was designed
to give an assessment of drinking water quality in urban and suburban areas,
and it may be considered to comprise the baseline against which current
concentrations of toxic substances can be compared. However, mercury was
not measured in this survey but was covered in a separate study conducted
in 1970-1971 by the Environmental Protection Agency. Results of this survey,
as summarized by Hammerstrom et al. (1972), disclose that 261 (96 percent)
of the 273 communities sampled had less than 1 ppb of mercury; 11 (4 percent)
were between 1 and 5 ppb; and one exceeded the 5 ppb level.
The above indication of a mercury level above 5 ppb led to an exten-
sive follow-up sampling program in which 192 raw and finished water samples
were collected at four plants in this system over a 3-week period. The
mercury concentration was found to be less than 0.25 ppb in 153 samples, and
less than 0.8 ppm in the remaining 30, casting some doubt upon the original
analyses.
2-23
-------
100
90
0.1
0.2 0.3 0.4 0.5
Mercury in Sediment, ppm
0.6
Figure 2.6. Frequency distribution of mercury in Great Lakes
sediments (U.S. Environmental Protection Agency,
1976a).
2-24
-------
More recent data confirm the generally low level of mercury in drink-
ing water supplies, as indicated by Table 2.10 which summarizes mercury
monitoring data for 1975 and 1976 taken from the computer data base main-
tained by the Basic Data Unit of the Water Supply Division of the Environ-
mental Protection Agency (Kent, 1976). Of the total of 512 readings, 506
were below 2 ppb; of these, 460 (89.8 percent) were below the detection
limit (0.5 ppb). Only six samples (1.2 percent) exceeded 2 ppb.
SLUDGE
In sludge resulting from the treatment of wastewater, mercury has not
commonly been included in the metals for which analyses have been done, and
analytical data are fairly sparse. However, the data reported below are
widely dispersed geographically, and are believed to be representative of
U.S. sludge mercury levels.
Salotto et al. (1974) reported the results of the analysis by the
Environmental Protection Agency of about 100 digested sludge samples
collected from 33 wastewater treatment plants in 13 states during the
period from the summer of 1971 through 1973. They found the distribution
of metals concentrations, including mercury, to characteristically have a
lognormal distribution. The arithmetic mean mercury concentration was 10
ppm, the geometric mean was 6.5 ppm, and the median was 6.6 ppm. They
also found that the variation of any metal in sludges from a given plant
was less than the plant-to-plant variation.
In another geographically broad-based study, Furr et al. (1976)
reported the analyses for 68 elements in sludge samples collected during
1972-1973 from 16 U.S. cities. Mercury concentrations were as follows:
Atlanta GA
Cayuga Heights NY
Chicago IL
Denver CO
Houston TX
Ithaca NY
Los Angeles CA
Miami FL
Hg, ppm
6.9
10.8
6.1
3.6
3.8
13.6
7.1
15.5
Milwaukee WI
New York NY
Philadelphia PA
San Francisco CA
Schnectady NY
Seattle WA
Syracuse NY
Washington DC
Hg, ppm
3.4
15.0
4.7
18.0
9.1
8.2
6.4
5.8
The mean concentration of these analyses is 8.5 ppm; and the median is
7.0 ppm, in good agreement with Salotto's mean and median values. The
extreme variability evident in concentrations of such heavy metals as
cadmium was absent for mercury. The highest value was only five times as
great as the lowest, whereas for lead and cadmium the ratio ranged from
55 to 65.
Very few data have been published which permit estimation of trends in
mercury levels in sludges. One piece of evidence comes from Chicago, which
since 1969 has had an Industrial Waste Ordinance which has limited the levels
2-25
-------
TABLE 2.10. MERCURY IN DRINKING WATER SUPPLIES
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
New Jersey
New Mexico
New York
North Dakota
Ohio
Oklahoma
Oregon
Ponnsy 1 van i a
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Guam
Puerto Rico
Total
Number of
Analyses,
:0.0005 ppm
16
3
1
7
it
1
36
1
1
1
7
9
11
4
4
2
13
22
30
8
1
1
3
14
3
2
1
83
16
15
1
1
23
1
3
57
3
2
11
2
5
3
7
4
4
13
460
Number of
Analyses,
>0.005 ppm
1
1
3
12
3
1
1
3
1
1
12
2
1
3
1
1
1
1
1
1
1
52
Total
Number of
Analyses
1
17
3
1
10
4
1
48
4
2
1
7
9
11
4
5
2
16
22
31
8
1
1
3
14
4
2
1
95
18
15
1
1
23
1
4
60
4
2
12
3
6
4
7
4
5
13
1
512
Maximum
Concentration,
ppm
0.0030
0.0005
<0.0005
<0.0005
0.0010
< 0.0005
<0.0005
0.0010
0.0010
0.0025
<0.0005
<0.0005
<0.0005
<0.0005
<0.0005
0.0010
<0.0005
0.0013
<0.0005
0.0005
<0.0005
<0.0005
<0.0005
< 0.0005
<0.0005
0.0010
<0.0005
<0.0005
0.0010
0.0010
<0.0005
<0.0005
<0.0005
<0.0005
-------
Since rocks are the precursors of soils, mercury content in soils
undisturbed by man would be expected to approximate those found in rocks.
This appears to be the case, as evidenced by results of U.S. soil studies
conducted by the U.S. Geological Survey (Shacklette et al., 1971). Samples
(912) of soils and other regoliths (loose surface rocks) were collected
from sites approximately 59 miles apart throughout the United States. The
geometric mean of all samples was 0.071 ppm (0.112 ppm arithmetic mean).
The geometric mean for the United States east of the 97th meridian was
0.096 ppm (0.147 ppm arithmetic mean); the geometric mean for the western
United States was 0.055 ppm (0.083 ppm arithmetic mean). Of all locations
sampled, 67 percent contained less than 0.080 ppm, and only 16 percent
exceeded 0.175 ppm.
In a similar survey covering 29 eastern states, Wiersma and Tai (1974)
found no significant difference between mercury concentrations in cropland
and noncropland. Geometric means were 0.063 and 0.54 ppm, and arithmetic
means were 0.08 and 0.07 ppm, respectively. These average values were not
significantly different from the averages found by Shacklette et al. for
western states.
Additional data on mercury concentrations in U.S. soils are available
from the Environmental Protection Agency's 1972 National Soils Monitoring
Program. Results of mercury analyses are shown in Table 2.12 (Gowen et al.,
1973). In each Standard Metropolitan Statistical Area (SMSA) except
Fitchburg, Massachusetts, urban area soils had significantly higher mercury
concentrations than the corresponding suburban area soils. A number of the
values for suburban soils appeared to be exceptionally low in light of the
U.S. soil averages determined by Shacklette et al. (1971) and Wiersma and
Tai (1974). Closer agreement was exhibited by the results of a similar
National Soils Monitoring Program the following year at five different
cities (U.S. Environmental Protection Agency, 1974a), which are also
summarized in Table 2.12. As in the previous study, mercury levels in urban
soils were found to be significantly higher than those in suburban soils;
average suburban soil concentrations (geometric means) ranged from 0.08 to
0.17 ppm, consistent with Shacklette and Wiersma and Tai. The Tacoma,
Washington, results may be atypical since this is the site of a large copper
smelter noted for the variety of feed materials which it processes.
One of the principal noncrop uses of mercurial fungicides is on grass
of the greens at golf courses which are particularly susceptible to fungus
diseases. Thus, mercury content of golf-course soils can be elevated, as
evidenced by the findings of an unpublished EPA study of 94 golf courses in
the northern and central United States (U.S. Environmental Protection Agency,
1974b). The arithmetic mean for greens and fairway cores were as follows:
Mercury Concentration, ppm
Soil Core Depth Greens Fairways
0.0-10.1 cm 72.7 6.8
10.1-20.3 cm 30.5 0.97
20.3-30.5 cm 14.1 0.52
2-29
-------
TABLE 2.12. CONCENTRATIONS OF MERCURY IN URBAN
AND SUBURBAN SOILS
Mercury Concentration, ppm
Number of
Location Samples
Washington DCa
Urban
Suburban
o
Evansville IN
Urban
Suburban
Pittsfield MAa
Urban
Suburban
Greenville SC3
Urban
Suburban
o
Tacoma WA
Urban
Suburban
Des Moines I A
Urban
Suburban
Fitchburg MA
Urban
Suburban
Lake Charles LA
Urban
Suburban
Pittsburgh PAb
Urban
Suburban
Reading PAb
Urban
Suburban
52
64
34
30
40
5
24
62
47
48
59
25
26
10
16
54
51
138
10
41
Arithmetic
Mean
0.48
0.16
0.27
0.09
0.33
0.17
0.17
0.10
0.76
0.19
0.44
0.01
0.34
0.24
0.06
0.01
0.64
0.09
0.63
0.10
Geometric
Mean Range
0.25
0.13
0.16
0.08
0.25
0.15
0.12
0.09
0.42
0.17
0.103
0.004
0.290
0.167
0.020
0.002
0.459
0.044
0.292
0.080
0.07-7.81
0.03-1.12
0.04-3.55
0.04-0.25
0.11-2.51
0.07-0.27
0.06-1.19
0.05-0.27
0.08-7.90
0.10-0.54
0.00-15.39
0.00-00.15
0.08-00.83
0.00-00.50
0.00-00.29
0.00-00.18
0.11-02.09
0.00-00.74
0.04-02.84
0.00-00.44
Positive
Detection,
%
89
16
100
90
50
7
100
68
100
93
Source: U.S. Environmental Protection Agency, 1974a, 1973 data.
'Source: Gowen et al., 1973, 1972 data.
2-30
-------
The maximum value found (0 to 10 cm sample) was 338 ppm. Since neither
greens nor fairways are tilled, the above-background mercury concentrations
at depths of up to 30 cm are evidence of migration of applied mercurial
fungicides.
TERRESTRIAL BIOTA
Vegetation
Mercury concentrations in tree species of unpolluted areas such as
Cades Cove, Tennessee, in the Great Smokey Mountains and Lake Powell, Utah,
average 0.02 to 0.03 ppm (Shacklette, 1970; Huckabee, 1973). In the more
urban areas of Missouri and New Haven, Connecticut, concentrations are
higher, ranging from 0.2 to 1.0 ppm (Shacklette, 1970; Smith, 1972). In
New Haven it is interesting to note that even at 14 km from the city, mercury
concentrations are similar to those in the city. In studies of vegetation in
the vicinity of a New Haven oil-fired power plant, mercury concentrations did
not vary significantly with distance and in general were similar to levels
found throughout the city (Mondano and Smith, 1974). Ohio levels were found
up to 0.03 ppm, similar to Cades Cove and Lake Powell. In contrast, trees
and shrubs at Red Devil, Alaska, growing in soil over a cinnabar (HgS) vein,
contain almost a hundred times more mercury, 1.0 to 1.25 ppm (Shacklette,
1970). Mercury levels vary between leaves and twigs, however, with no
consistent trend. In some instances levels are higher in leaves, in others,
stems.
As was the case for trees and shrubs, mercury levels found in herba-
ceous growth in unpolluted areas generally range from 0.02 to 0.03 ppm. Ohio,
Utah, and Nevada have these levels (Devendorf, 1975; Standiford et al., 1973;
Gay, 1976). The effect of air pollution from a copper smelter is evident in
the data from Tacoma, Washington, where mercury concentrations in garden
vegetables ranges from 1.1 to 4.0 ppm within 3.2 km of the facility (Ratsch,
1974). Levels do decrease with distance from this facility. However, even
at 9.7 km, levels are ten times higher than those in unpolluted areas.
Mercury concentrations found in grasses do not exceed the 0.02 to 0.03
ppm found in trees, shrubs, and herbs under unpolluted conditions. Even
samples near a stack emitting fly ash in Oak Ridge, Tennessee, contained only
0.025 ppm (Huckabee, 1973).
Mosses and lichens have a tendency to accumulate more mercury than
trees, shrubs, grasses, or herbs, even in unpolluted areas. For example, at
Cades Cove, Tennessee, mercury concentration in trees, shrubs, herbs, and
grasses averaged 0.02 to 0.03 ppm, whereas levels in mosses ranged from
0.092 to 0.118 ppm (Huckabee, 1973). Levels in mosses and lichens in New
Haven, Connecticut, are again higher than they were in other plant types,
averaging over 1.0 ppm (Mondano and Smith, 1974). Mosses and lichens in
all other sample areas except Oak Ridge, Tennessee, 1.18 ppm (Huckabee,
1973), contained levels similar to those found at Cades Cove. Some variation
does exist, however, the tendency is toward higher concentrations in areas of
higher population and industry (Yeaple, 1972).
2-31
-------
Mammals
Levels of mercury found in mammals vary among regions of the U.S.,
among species, within species, and with age. There are no national sampling
programs for mammals and few local studies have emphasized this group of
animals. Cumbie (1975a,b) and Cumbie and Jenkins (1974) have shown that
mercury levels in mammals vary among physiographic provinces in the Southeast
(Table 2.13). Body burdens increase toward the coast, with levels being
highest in the Lower Coastal Plain, intermediate in the Upper Coastal Plain,
and lowest in the Piedmont. This has also been shown to occur with other
metals (Cumbie 1975a) and may be a result of different levels of soil
mineralization in the provinces.
Lynch (1973) indicates that squirrels in rural areas may accumulate
higher mercury levels than those in urban environments; this is thought to
be related to the ingestion of seeds treated with mercurial fungicides.
Levels may also vary among species; herbivorous species such as deer and
livestock tend to have lower levels than omnivorous and carnivorous species
such as fox and mink. Carnivores which feed at least in part on aquatic
organisms tend to accumulate the highest levels of mercury. Bioaccumulation
is also illustrated by the fact that adults tend to have higher levels than
young animals. Mercury concentrates at different rates in different parts
of the body. Concentration values tend to be highest in hair (dry weight
basis), intermediate in liver (wet weight), and lowest in muscle, fat, and
milk (wet weight). On a dry weight basis, mercury levels are probably
greatest in the liver (Cumbie, 1975a).
Birds
Mercury occurs in birds in all parts of the U.S. The amounts vary
among years, seasons, regions, and bird species. A nationwide monitoring
program in starlings revealed declining mercury levels, which were
attributed to the decline in the use of pesticides and more stringent
discharge requirements (Table 2.14). No differences were detected between
urban and rural environments.
A national survey of mercury in woodcocks illustrates that mercury
levels in birds may vary in different regions of the U.S. (Clark and McLane,
1974) (Table 2.15). Woodcock in the southern U.S. contained more mercury
than those in the North; this was presumed to reflect greater ambient levels
of mercury in the South. A national study of mercury levels in duck wings
also demonstrates regional differences (Heath and Hill, 1974). Ducks collec-
ted in the Atlantic and Pacific flyways had greater levels of mercury than
those from the Mississippi and central flyways (Table 2.16).
In addition, Heath and Hill (1974) show that differences in concen-
trations may occur in similar species; black duck levels were about twice as
high as mallard levels. This is probably related to the fact that black
ducks are more carnivorous and thus higher on the food chain. Species
differences are illustrated when diving and sea ducks were shown to have
considerably higher mercury levels than dabbling (pubble) ducks (Table 2.17)
2-32
-------
TABLE 2.13. MERCURY LEVELS IN TERRESTRIAL MAMMAL HAIR
10
I
U)
Location
Florida
Statewide
Northern
Southern
Alachua County
Dade County
Eglin Air Force Base
Georgia
Piedmont
Upper Coastal Plain
and lower coastal
plain
Lower Coastal Plain
Concentration ,
ppm wet weight
Organism
Raccoon, Procyon lotor, adult
Raccoon, P. lotor, juvenile
Raccoon, P. lotor
Raccoon, P. lotor, adult
Raccoon, P. lotor, -juvenile
Raccoon, P. lotor, adult
Raccoon, P. lotor, juvenile
White-tailed deer, Odocoileus
virginianus
Bobcat , Lynx ruf us
Gray fox, Urocyon cinereoargenteus
Mink, Mustela vison
Opossum, Didelphis virginiana
Otter, Lontra canadensis
Raccoon, P. lotor
White-tailed deer, 0. virginianus
Bobcat, L. ruf us
Raccoon, P. lotor
Bobcat, L. ruf us
Gray fox, U. cinereoargenteus
Mink, M. vison
Opossum, D. virginiana
Otter, L. canadensis
Raccoon, P. lotor
Red fox, Vulpes vulpes
White-tailed deer, 0. virginianus
Mean
6.52a
2.65a
7.50a
4.35a
10. la
2.65a
6.38a
40. Ia
4.4a
NDa
2.39a
0.50a
10. 7a
1.30a
15. 9a
0.13
13.05a
7.36
0.93a
0.763
10. 7a
2.39a
37.6aa
6.12
0.49a
Range
0.52-35.7
0.84-10.1
0.13-0.4a
0.39-23.4
ND-1.06
2.3-17.3
0.39-3.31
9.3-26.8
ND-0.59a
1.14-24.0
0.31-15.2
0.22-2.31
0.82-8.41
5.9-15.4
0.39-23.4
15.8-67.9
0.23-50.6
0.19-0.26
ND -0.21a
Reference
Cumbie, 1975a
Cumbie & Jenkins ,
Cumbie, 1975a
Cumbie & Jenkins ,
Cumbie, 1975a.
Cumbie & Jenkins ,
Cumbie, 1975b
Cumbie & Jenkins,
Cumbie, 1975b
Cumbie, 1975a
Cumbie, 1975b
Cumbie & Jenkins,
Cumbie, 1975b
Cumbie & Jenkins,
1974
1974
1974
1974
1974
1974
-------
TABLE 2.13. (Continued)
Location
Organism
Concentration,
ppm wet weight
Mean
Range
Reference
Piedmont
Upper Coastal Plain Opossum, I), virginiana 0.28a 0.16-0.38
Raccoon, £. lotor 1.553 0.28-3.81
Red fox, V. vulpes 2.34 0.06-5.67
White-tailed deer, 0. virginianus 0.55S 0.24-0.98
aValues in ppm dry weight.
bAll data collected 1972-1973.
I
OJ
.C-
-------
TABLE 2.14. MERCURY LEVELS IN STARLINGS (STURNUS VULGARIS); 1970, 1971, AND 1973a
Concentration, ppm wet weight^
Location
Alabama
Marion
Mobile
Tallaega
Arizona
Graham
Maricopa
Nava j o
Phoenix
Yavapi
Arkansas
Lonoke/Pulaski
K> Stuttgart
w Yell/Pope
Ln
California
Bakersfield
Colusa
Imperial
Inyo
Kern
Los Angeles
Mo doc
Monterey
Sacramento
Shasta
Stanislaus
Ventura
Colorado
Adams
Brighton
Greeley
1970 1971 1973
<0.05
0.07 0.07
<0.05
<0.05
<0.05
<0.05
0.01 <0.01
<0.05
0.05
0.06 0.03
<0.05
0.05 <0.01
0.05
0.09
0.08
<0.08
0.01 <0.01
0.07
<0.05
0.04 0.06
<0.05
0.07
<0.05
<0.05
<0.01
0.02
Concentration, ppm wet weightb
Location
Colorado
La Plata and
Rio Grande
Montrose
Otero
Connecticut
Connecticut River
Valley
New London
Delaware
Dover
Florida
Bay
Gainesville
Hardee
Madison
Polk
Georgia
Atlanta
Pike
Wayne
Idaho
Boise
Franklin
Minidoka
Nezperce
Owyhee
Illinois
Chicago
Cook
1970
<0.05
0.05
<0.05
0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
0.06
0.05
0.05
0.07
1971 1973
0.03 <0.01
0.03
0.21 <0.01
0.03 0.01
0.07 <0.01
0.01 <0.01
-------
TABLE 2.14. (Continued)
Concentration, ppm wet weight
Location
Illinois (cont'd)
Sagamon
Stephenson
Indiana
Evansville
Gary
Henry
Highland
Iowa
Butler
Polk
Pottawattomie
Des Moines
Kansas
Garden City
Hamiltion & Kearny
Marion
Nemaha
Rowl ins
Smith
Kentucky
Hopkins
Ohio
Louisiana
Baton Rouge
Jefferson
Rapides
Maine
Gray
Penobscot
1970 1971 1973
<0.05
<0.05
<0.01
0.01
0.19
0.02
<0.05
<0.05
<0.05
Not de- <0.01
tected
<0.01 0.01
0.15
0.15
0.18
0.10
0.07
0.10
<0.05
0.05 0.02
<0.05
0.10
0.06 <0.01
0.05
Concentration, ppm wet weight
Location
Maryland
Annapolis
Patuxent
Prince George
Massachusetts
Quincy
Michigan
Chippewa
Grand Traverse
Inaham
Kent
Lansing
Minnesota
Aitkin
Pine
Swift
Twin Cities
Mississippi
Harrison
Jackson
Leake
Starkville
Missouri
Bellinger
Maiden
Stoddard
Montana
Meagher
Missoula
1970 1971
<0.01
0.10
0.05
0.05
0.06
0.05
0.05
0.03
<0.05
<0.05
<0.05
0.01
<0.05
0.08
<0.05
0.01
<0.05
0.02
0.05
0.06
<0.05
1973
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
0.01
-------
TABLE 2.14. (Continued)
Concentration, ppm wet weight^
Location
Montana (cont ' d)
Richland
Yellowstone
Nebraska
Antelope
Clay
Keith
Lincoln
North Platte
Nevada
N> Clark
u> Humboldt
^ McGill
Nye
Reno
White Pine
New Jersey
New Brunswick
New Mexico
Bernalillo
Carlsbad
Chaves
Farmington
Luna
Quay
Santa Fe & Torrence
New York
Albany
Jamestown
Oswego
1970 1971 1973
0.08
<0.05
<0.05
<0.05
0.05
<0.05
0.01 0.01
0.06
0.06
0.05 <0.01
0.09
0.02 0.20
0.11
0.22 <0.01
<0.05
0.05 <0.01
<0.05
0.025 <0.01
0.08
<0.05
<0.05
<0.01
0.03 <0.01
0.06
Location
New York
Rennselaer
North Carolina
Macon
Pender
Raleigh
Union
Wilkes
North Dakota
Bismarck
Cavelier
Dickey
Manden
Ward
(Thi n
l/Ll-LU
Columbus
Erie
Jefferson
Washington
Oklahoma
Canadian
Greer
Nowata
Okmulgee
Tishomingo
Oregon
Baker
Corvallis
Harney
Klamath
Concentration, ppm wet weight"
1970
0.10
<0.05
<0.05
<0.05
0.05
0.11
<0.05
0.05
0.11
<0.05
0.08
0.13
0.08
0.13
0.09
0.14
0.10
0.11
1971 1973
0.01 <0.01
0.01
0.02
0.06 0.06
0.01 <0.01
0.32 0.05
-------
TABLE 2.14. (Continued)
I
w
CD
Concentration, ppm wet weight
Location
Oregon (cont'd)
Lane
Wilsonville
Yamhill
Pennsylvania
Cuzerne
Pittsburgh
Sommerset
South Carolina
Aiken
Columbia
South Dakota
Brown
Hughes
Pierre
Potter
Tennessee
Davidson
Nashville
Texas
Clay
Hillsboro
Morris
San Antonio
TT+- o>i
u tan
Salt Lake City
Sevier/Millard
Weber
1970 1971 1973
1.90
0.62 0.05
1.50
0.10
0.06 <0.01
0.10
<0.05
<0.01
0.05
<0.05
0.05 0.13
<0.05
0.05
0.03 <0.01
0.08
0.04 0.01
<0.05
0.03 <0.01
0.030 0.04
0.08
0.09
Concentration, ppm wet weight
Location
Utah (cont'd)
Sevier/Millard
Weber
Vermont
Add is on
Champlain Valley
Virginia
Amherst
Blacksburg
Caroline
Prince George
Washington
Pierce
Spokane
Whitman
Yakima
West Virginia
Elkins
Wisconsin
Curtiss
Horicon
Portage
Tempeleau
Wyoming
Big Horn
Brook
Goshen
Washakie
Wo r land
1970
0.08
0.09
0.05
0.08
0.18
0.22
0.05
0.07
0.06
0.06
0.05
<0.05
0.05
<0.05
<0.05
0.06
1971 1973
0.10
0.01 0.03
<0.01 <0.01
0.02 0.03
0.01 0.01
0.03
0.03
0.01
^Sources: For 1970 - Martin (1972); 1971 - Martin
Each value represents analysis of a composite of
and Nickerson (1973); 1973 - White et al. (1976).
10 starlings.
-------
TABLE 2.15. MERCURY LEVELS IN WOODCOCK
(PHILOHELA MINOR) LIVER, 1970-1971
Location
Alabama
Arkansas
Florida
Georgia
Kentucky
Louisiana
Maine
Maryland
Michigan
Minnesota
Mississippi
Missouri
New Hampshire
New Jersey
New York
North Carolina
Pennsylvania
Rhode Island
South Carolina
Tennessee
Vermont
West Virginia
Wisconsin
Number of
Samples
5
5
4
5
5
9
5
5
5
5
10
4
4
9
5
5
5
4
5
4
4
5
5
Concentratiot
Mean
0.61
0.17
0.28
0.17
0.09
0.25
0.07
0.22
0.09
0.06
0.17
0.13
0.09
0.19
0.15
0.37
0.10
0.13
0.57
0.35
0.09
0.08
0.10
i, ppm wet weight
Range
0.29-0.92
0.06-0.26
0.18-0.36
0.05-0.23
0.05-0.14
0.13-0.36
0.05-0.12
0.14-0.28
0.05-0.12
0.05-0.08
0.08-0.27
0.05-0.17
0.07-0.12
0.08-0.46
0.08-0.23
0.05-0.87
0.07-0.17
0.05-0.22
0.17-1.10
0.20-0.66
0.07-0.12
0.05-0.14
0.05-0.15
Source: Clark and McLane, 1974.
2-39
-------
TABLE 2.16. MERCURY LEVELS IN BLACK DUCK AND MALLARD WINGS
(AMAR RUBRIPES AND A. PLATYHYNCHER), 1969-1970
Location
Atlantic Flyway
Connecticut
Delaware
Florida and Georgia
Maine
Maryland
Massachusetts
New Hampshire
New Jersey
New York
North Carolina
Pennsylvania
Rhode Island
South Carolina
Vermont
Virginia
Mississippi Flyway
Alabama
Arkansas
Indiana
Illinois
Iowa
Kentucky
Louisiana
Michigan
Minnesota
Mississippi
Missouri
Ohio
Tennessee
Wisconsin
Central Flyway
Colorado
Kansas
Organism
Black duck
Black duck
Mallard
Black duck
Black duck
Mallard
Black duck
Black duck
Black duck
Mallard
Black duck
Mallard
Black duck
Black duck
Mallard
Black duck
Black duck
Mallard
Black duck
Black duck
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Number of
Samples
3
2
2
3
3
2
4
2
5
3
4
3
2
3
3
3
2
3
2
3
2
1
6
1
6
4
1
5
3
5
2
5
3
4
5
4
6
Concentration, ppm wet weight
Mean
0.21
0.20
0.12
0.19
0.11
0.08
0.22
0.20
0.18
0.11
0.33
0.11
0.15
0.16
0.08
0.19
0.18
0.13
0.26
0.15
0.16
0.06
0.08
0.06
0.06
0.08
0.09
0.08
0.11
0.08
0.08
0.07
0.10
0.08
0.26
0.08
0.06
Range
0.14-0.24
0.15-0.25
0.09-0.18
0.16-0.24
0.10-0.13
0.08-0.08
0.21-0.22
0.20-0.20
0.15-0.23
0.10-0.12
0.18-0.80
0.09-0.12
0.14-0.16
0.12-0.19
0.06-0.10
0.14-0.22
0.18-0.19
0.11-0.15
0.14-0.39
0.13-0.17
0.15-0.16
0.06-0.10
0.05-0.08
0.06-0.10
0.06-0.09
0.08-0.14
0.06-0.10
0.07-0.08
0.05-0.11
0.08-0.12
0.07-0.12
0.05-1.00
0.07-0.10
Trace-0.09
2-40
-------
TABLE 2.16. (Continued)
Location
Central Flyway
Montana
Nebraska
New Mexico
North Dakota
Oklahoma
South Dakota
Texas
Wyoming
Pacific Flyway
Arizona and
New Mexico
California
Colorado
Idaho
Montana
Nevada
Oregon
Utah
Washington
Wyoming
Organism
(cont'd)
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Mallard
Number of
Samples
4
7
3
6
4
6
6
3
3
8
3
8
4
3
7
5
8
2
Concentration
Mean
0.07
0.09
0.09
0.08
0.08
0.06
0.06
0.08
0.12
0.08
0.10
0.10
0.10
0.37
0.09
0.09
0.09
0.12
, ppm wet weight
Range
0.05-0.09
0.07-0.13
0.06-0.10
0.06-0.11
0.05-0.11
0.05-0.09
0.05-0.07
0.07-0.09
0.09-0.14
0.05-0.11
0.09-0.12
0.08-0.15
0.10-0.11
0.23-0.55
0.06-0.10
0.06-0.10
0.05-0.18
0.10-0.13
Source: Heath and Hill, 1974.
2-41
-------
TABLE 2.17. MERCURY LEVEL IN DUCK BREAST MUSCLE, 1970-1971
Location
Location
Alabama
Baldwin County
Mobile County
California
San Francisco Bay
Tule Lake NWR
Maryland
Chesapeake Bay
West River
Minnesota
A nas six
Jtasra
Nortli Carolina
Coro 1 1 a
Craudy
Pamlico Pt.
North Dakota
Audubon NWR
Pettibone
Stan ton
Woodworth
South Dakota
MacPhearson
Marshall County
Sandlake NWR
Texas
Port Lavaca
Vermont
Lake Champlain
Ulah
Brigham City
Organism
Gadwall, Anas strepera
Lesser scaup, Aythya affinis
Gadwall, Anas strepera
Lesser scaup, Aythya affinis
Greater scaup, Aythya marila
Lesser scaup, A. affinis
Mallard, Anas platyrhynches
Pintail, A. acuta
Lesser scaup, Aythya affinis
Mallard, Anas platyrhynches
Canvasback, Aythya valisineria
Common scoter, Melanitta nigra
Mallard, Anas platyrhynches
Surf scoter, Melanitta perspicillato
White-winged scoter, M. deglandi
Canvasback, Aythya valisineria
Mallard, Anas platyrhynches
Lesser scaup, Aythya affinis
Lesser scaup, A. affinis
Mallard, Anas platyrhynches
Mallard, A. pla ty rliyncliL's
Lessor scaup, AyLhya affinis
Mallard, Anas platyrhynches
Mallard, A. plalyrliynchc.s
Mallard, A. platyrhynches
Lesser scaup, Aythya affinis
Mallard, Anas platyrhynches
Lesser scaup, Aythya affinis
Mallard, Anas platrhynches
Lesser scaup, Aythya affinis
Mallard, Anas platrhynches
Lesser scaup, Aythya affinis
Mottled duck, Anas fulvigula
Black duck/Mallard, Anas rubripes/
A. platyrhynches
Common goldeneye, Bucephala clangula
Creater scaup, Aythya marila
Lesser scaup, A. affinis
Mallard, Anas platyrhynches
RiiiK-neckcd duck, Aythya collaris
No. of
Samples
4
9
12
7
8
4
16
5
16
16
8
3
8
1
4
8
16
8
7
8
8
8
8
7
6
16
8
6
8
8
8
16
16
6
8
1
2
16
3
Concentration,
Mean
0.06
0.21
0.89
0.48
0.38
0.27
0.16
0.09
0.37
0.14
0.14
0.12
0.03
0.17
0.30
0.10
0.11
0.16
0.28
0.07
0.03
0.21
0.04
0.09
0.02
0.31
0.03
0.16
0.03
0.31
0.03
0.28
0.26
0.11
0.42
0.02
0.13
0.04
0.1 1
ppm wet weight
Range
0.02-0.09
0.12-0.34
0.08-3.90
0.14-2.00
0.09-0.68
0.03-0.68
0.02-1.06
0.05-0.15
0.02-1.77
0.02-1.47
0.05-0.24
0.06-0.20
0.01-0.06
0.07-0.61
0.08-0.16
0.03-0.24
0.07-0.25
0.10-0.47
0.03-0.12
<0.01-0.16
0.03-0.70
0.01-0.10
0.03-0.18
0.02-0.03
0.04-0.70
0.01-0.05
0.09-0.19
0.02-0.06
0.15-0.65
0.02-0.05
0.06-1.00
0.07-0.43
0.04-0.17
0.21-0.76
0.12-0.14
0.0 1-0. 11)
0.0(i-0. IK
Source.' : llaskett , 1 975 .
2-42
-------
(Baskett, 1975). Dabbling ducks are more herbivorous and feed in shallow
water or on the ground. Diving and sea ducks are more carnivorous and feed
on fish and botton-dwelling organisms which bioaccumulate mercury from the
water and sediment.
Numerous local studies of total mercury levels in various species of
birds have been conducted in the U.S. Several studies (Brock et al., 1973;
Buhler et al., 1973) have shown that levels of mercury in birds may vary
with the availability of mercury-contaminated foods. Granivorous birds had
higher levels at crop-planting time when mercury-coated seeds were used than
at other times of the year. Birds with access to mercury-treated seeds may
have higher levels than birds from urban or nonfarm areas (Lynch, 1973) .
Some of the highest levels reported in birds have come from Lake St. Clair,
Michigan, in recent years; however, the levels reported in bird eggs from
this area have declined (Table 2.18). The decline is probably related to a
decrease in the amount of mercury discharged into lakes and streams.
Studies in other areas needed to corroborate the decline have not been made.
Mercury ingested by birds accumulates at different rates in different
parts of the body (Table 2.19) (Buhler, 1977). Values tend to be highest in
feathers but occasionally are exceeded by those in liver tissue. Liver
concentrations average from two to six times higher than muscle tissue
concentrations. The mercury background level for pheasants raised in
captivity in Oregon is 0.001 to 0.002 ppm in muscle (Buhler, 1977). On this
basis, a significant accumulation of mercury was found in over 90 percent of
the Oregon pheasants collected during 1970. The mean concentration of mercury
in muscle tissue from these birds was 0.173 ppm, with approximately 7.5 per-
cent of the pheasants exceeding the 0.5 ppm FDA guideline value for mercury
in foods. The highest concentrations of mercury observed in this survey
occurred in one bird from the Willamette Valley that contained 6.33 ppm in
breast muscle and 12.8 ppm in the liver. The concentration of mercury in
Oregon pheasants varied appreciably among seasons and areas, but maximum
tissue residues appeared to be related to the time of greatest availability
of seeds treated with mercury fungicides in a particular area.
Almost all of the mercury found in the muscle tissue from the birds
collected in 1970 was in the form of methylmercury (Table 2.20), suggesting
that these birds had been exposed primarily to seeds dressed with methyl-
mercuric dicyanidiamide. This chemical has been widely used in Oregon
agriculture and in 1970 it accounted for over 80 percent of the mercury
fungicide used in the state.
AQUATIC BIOTA
Levels of environmental mercury appear to be considerably highest in
the tissues of aquatic biota in Atlantic coastal environs—both freshwater
and marine. The sources of contamination in this region of the U.S. are
primarily industrial. Regionally high values also occur in the states of
the Pacific Northwest—particularly in the Columbia and Snake River
drainages in Washington and Idaho. The elevated levels result from both
mining activity and the leaching of soils naturally high in mercury content.
2-43
-------
TABLE 2.18. MERCURY LEVELS IN BIRDS OF LAKE ST. CLAIR, MICHIGAN
to
-p-
Organism
Bald eagle, Haliaeetus leucocephalus
American bittern, Botaurus
lentiginosus
Black-crowned night heron,
Nycticorax nycticorax
Black tern, Chlidonias niger
Blue-winged teal, Anas discors
Canada goose, Branta canadensis
Common gallinule, Gallinula
chloropus
Common tern, Sterna hirundo
Dunlin, Calidris alpina
Great blue heron, Ardea herodias
Great egret, Casmerodius albus
Killdeer, Charadrius vociferus
Lesser scaup, Aythya af finis
Organ or
Tissue
Egg
Carcass
Liver
Carcass
Liver
Egg
Carcass
Liver
Breast muscle
Liver
Kidney
Breast muscle
Liver
Kidney
Carcass
Liver
Carcass
Liver
Egg
Carcass
Liver
Carcass
Liver
Carcass
Liver
Carcass
Liver
Breast muscle
Liver
Kidney
Concentration ,
Mean
0.4
0.55
1.75
2.8
14.0
0.77
0.68
2.47
0.68
1.50
1.40
<0.10
0.18
<0.10
0.41
1.4
3.4
18.1
2.72
0.15
0.95
14.4
97.0
0.74
6.3
0.45
2.2
0.81
3.2
2.01
ppm wet weight
Range Reference
Wiemeyer et al., 1972
Dustman et al., 1972
0.046-0.11
0.41-1.3
1.3-2.6
0.10-2.3
0.35-5.0
0.27-4.4
0.4-7.5 Dustman et al, 1972
2.1-39.0
0.63-6.25
<0. 10-0. 20
0.70-1.3
5.3-23.0
14.6-136.0
0.14-0.68
0.5-2.3
0.54-1.2
1.8-3.4
0.96-2.3
-------
TABLE 2.18. (Continued)
t-o
I
Organism
Mallard, Anas platyrhynchos
Mallard, A. platyrhynchos
Ring-billed gull, Larus delawarensis
Scaup, Aythya spp.
Spotted sandpiper, Actitis macularia
Black-crowned night heron,
Nycticorax nycticorax
Common tern, Sterna hirundo
Great egret, Casmerodias albus
Mallard, A. platyrhynchos
Organ or
Tissue
Breast muscle
Liver
Kidney
Egg
Liver
Carcass
Liver
Liver
Carcass
Liver
Egg
Egg
Egg
Egg
Concentration, ppm wet weight
Mean
0.48
1.62
1.13
0.82
0.54 ± 0.83
0.41
1.22
0.99 ± 1.00
0.55
2.8
0.45
1.15
0.35
0.077
Range
<0. 10-1. 15
0.23-4.8
<0.10-3.5
0.22-2.7
0.14-0.70
0.65-1.8
0.20-0.76
0.69-2.16
0.21-0.45
<0. 05-0. 26
Reference
Dustman et al., 1972
Ford and Prince, 1975
Dustman et al., 1972
Ford and Prince, 1975
Dustman et al., 1972
Stendell et al., 1976
-------
TABLE 2.19. DISTRIBUTION OF MERCURY IN TISSUES
OF OREGON PHEASANTS
Total Mercury, ppm
Tissue
Male Pheasant
Female Pheasant
Feathers
Liver
Kidney
Crop and contents
Muscle
Gizzard
Skin
Brain
Heart
Testes
Femur
Gizzard contents
Fat
26.0
12.8
6.93
6.57
6.33
5.35
5.00
4.70
4.35
2.99
1.11
0.93
0.36
2.30
3.46
1.67
1.14
1.43
0.40
0.95
2.91
—
0.19
0.54
0.10
Source: Buhler, 1977.
TABLE 2.20. MERCURY AND METHYLMERCURY CONTENT
OF PHEASANT BREAST TISSUE
Year Bird Number
Total Mercury,
ppm
Methylmercury, Methylmercury,
ppm %
1970
14
23
26
50
1.14
2.11
2.71
0.337
1.3
1.8
2.6
0.35
114
85.3
95.9
103.8
Mean ± S.D. 99.8 ± 12.1
1972
212
215
220
221
0.088
0.911
3.032
0.486
0.096
0.430
0.324
0.024
110.2
47.2
27.2
4.9
Mean ± S.D. 47.4 ± 45.3
Source: Buhler, 1977.
2-46
-------
Other generally isolated incidences of aquatic biota contamination occur in
many states of the U.S. These levels are most often associated with a
point source of mercury emission, such as sewage treatment and chlor-alkali
plants, or nonpoint source runoff from agricultural or other use of mercurial
fungicides.
Mercury compounds enter aquatic organisms both indirectly through the
food web and directly by extraction from solution (Jernelb'v and Lann, 1971;
D'ltri, 1972; Peterson et al., 1973). From the available literature, it
can be seen that highest accumulations occur in fishes at the top of the
trophic structure, the sport fishes and piscivores. This seems to be the
major pathway for mercury accumulation in predator fish. Occasionally,
elevated levels were found in carp and suckers; these are due to direct
extraction, with less than 25 percent of their total mercury accumulation
coming through the food chain (Jernelb'v and Lann, 1971). Mercury and its
compounds are made available through biological methylation by micro-
organisms (Jensen and Jernelb'v, 1969; D'ltri, 1972).
Fish
Analysis of mercury in fishes collected as part of the National
Pesticides Monitoring Program (NPMP) was initiated in 1969 (Henderson et al.,
1972). Data are summarized in Tables 2.21 to 2.26 by geographical region.
Highest regional values were reported from the Atlantic coastal streams
(Regions 4 and 5). These concentrations are likely due to industrial
discharge rather than to either agricultural runoff or leaching of natural
minerals. Elevated concentrations in fishes from certain areas of the
Columbia and Snake Rivers in Washington and Idaho reflect contamination
from both mining activity and natural occurrence. On a regional basis,
overall lowest concentrations were found in Region 2, Texas, New Mexico,
Arizona, and Oklahoma. On a state basis, Alaska has the lowest amount of
contamination to date, less than 0.1 ppm. It should be noted, however,
that only two locations were sampled in Alaska and this is not an actual
assessment for the entire state.
In most cases, NPMP data reveal highest mercury concentrations in the
muscle tissue of the sport fishes, particularly largemouth bass, perch,
catfish, and walleye. Relatively low overall levels found in Region 6 may
reflect the larger proportion of forage fishes sampled. Elevated concen-
trations were found in the northern squawfish, a large minnow whose range
is restricted to the western states. This fish, like many of the game
fishes, is a voracious piscivore. Occasionally, elevated concentrations
were also found in carp and suckers. These data indicate that mercury
concentration is related to feeding habit, whether indirectly through a
food chain or directly from sediments.
A preliminary study from the National Marine Fisheries Service (1975)
reported the levels of mercury found in the muscle tissues of marine fish
species (Figure 2.7). Of the 106 species tested, only six had more than
50 percent of the samples above the FDA 0.05 ppm mercury guideline—blue
marlin, white marlin, gag, little tunny, black grouper, and Hawaiian red
2-47
-------
TABLE 2.21. LEVELS OF MERCURY IN FISH FROM REGION 1, NATIONAL PESTICIDES
MONITORING PROGRAM, 1969,a 1970,a AND 1972b
Concentration, ppm
Location 1969
Alaska
Chena River 0.07
Kenai River 0.09
Calfornia
Klamath River 0.16
Sacramento River 0.14
San Joaquin River 0.18
Hawaii
Manoa Stream
Waikele Stream
Idaho
Bear River
Salmon River
Snake River 0.26
Nevada
Colorado River
Truckee River 0.37
Oregon
Columbia River 0.56
Rouge River 0.44
Williamette River 0.18
Washingron
Columbia River
Snake River
Ice Harbor
Yakima River 0.19
Mean
1970
0.06
0.14
0.20
0.20
0.16
0.13
0.17
0.23
0.80
0.21
0.07
0.41
0.55
0.27
0.26
0.14
0.61
0.19
1972C
0.09
0.06
0.18
0.04
0.06
0.19
0.11
0.16
0.11
0.03
0.29
0.10
0.11
0.16
0.13
0.10
0.28
1969
0.06-0.09
0.06-0.12
0.12-0.22
0.11-0.19
0.14-0.20
0.08-1.25d
0.22-0.53C
0.15-1.25d
0.16-0.90f
0.13-0.23
0.3-0.9§
Range
1970
0.05-0.06
0.06-0.26
0.12-0.27
0.18-0.22
0.09-0.23
0.09-0.18
0.06-0.43
0.13-0.37
0.29-1.70d
0.08-0.43
0.05-0.09
0.21-0.65°
0.21-1.10d
0.14-0.51f
0.17-0.33
0.07-0.25
0.10-1.20d
0.07-0.27
1972
0.06-0.14
0.01-0.18
0.02-0.32
0.03-0.05
0.03-0.10
0.02-0.46
0.06-0.14
0.08-0.21
0.01-0.26
0.01-0.05
<0. 05-0. 50
0.08-0.23
0.04-0.18
0.04-0.29
0.02-0.47
0.03-0.18
0.03-0.64d
.Source: Henderson et al., 1972.
Source: Berger, 1974.
Calculated from author's data.
Northern squawfish.
Largemouth bass.
Brown bullhead.
g
Largescale sucker and smallmouth bass.
2-48
-------
TABLE 2.22. LEVELS OF MERCURY IN FISH FROM REGION 2, NATIONAL PESTICIDES
MONITORING PROGRAM, 1969,a 1970,a AND 1972b
Location 1969
Arizona
Colorado River <0.05
Gila River
New Mexico
Rio Grande
Oklahoma
Arkansas River 0.07
Canadian River
Red River
Verdigris River
Texas
Brazos River
Colorado River
Nueces River
Pecos River
Rio Grande River 0.04
Mean
1970
0.10
0.15
0.33
0.14
0.10
0.18
0.20
0.13
0.16
0.17
0.18
0.09
Concentration ,
1972C 1969
0.11 <0. 05-0. 05
0.25
0.21
0.07 <0. 05-0. 14
0.06
0.09
0.11
0.18
0.03
0.07
0.06 <0. 05-0. 06
ppm
Range
1970
<0. 05-0. 27
0.11-0.22
0.10-0.52d
0.06-0.22
0.06-0.21
0.10-0.24
0.05-0.44
0.05-0.24
0.14-0.19
<0. 05-0. 40
0.05-0.42
<0. 05-0. 17
1972
<0. 05-0. 49
0.10-0.41
0.16-0.28
<0. 05-0. 08
—
<0. 05-0. 12
0.06-0.15
0.06-0.17
0.11-0.46
0.02-0.06
0.01-0.10
0.01-0.11
Source: Henderson et al., 1972.
Source: Berger, 1974.
CCalculated from author's data
Largemouth bass.
2-49
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TABLE 2.23. LEVELS OF MERCURY IN FISH FROM REGION 3, NATIONAL PESTICIDES
MONITORING PROGRAM, 1969,a 1970,a AND 1972b
Concentration, ppm
Mean Range
Location 1969 1970 1972C 1969 1970 1972
Illinois
Illinois River 0.10 0.13 0.05 0.07-0.13 0.08-0.21 0.04-0.06
Ohio River 0.22 0.01 0.11-0.43 0.09-0.21
Indiana
Wabash River 0.19 0.12 0.15-0.25 0.07-0.16
Iowa
Mississippi River 0.16 0.20 0.12 0.10-0.25 0.11-0.33 0.08-0.18
Michigan
Lake Huron 0.07 0.07 0.06 <0.05-0.13 0.05-0.08 <0.05-0.07
Minnesota
Mississippi River 0.48 0.21 0.21-0.68d 0.09-0.46
Red River 0.39 0.31 0.53 0.36-0.41 0.13-0.60 0.32-0.75C
Missouri
Mississippi River 0.14 0.07 <0.05-0.20 0.06-0.10
Ohio
Ohio River 0.33 0.32 0.17 0.20-0.50 0.07-0.83d 0.06-0.24
Wisconsin
Lake Michigan 0.18 0.09 0.24 0.09-0.27 0.07-0.09 0.12-0.26
Lake Superior 0.10 0.17 0.18 <0.05-0.16 0.06-0.29 0.08-0.28
Wisconsin River 0.37 0.073 0.11-0.60 0.01-0.15
f\
Source: Henderson et al., 1972
Source: Berger, 1974.
Calculated from author's data.
Catfish.
Sauger.
2-50
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TABLE 2.24.
LEVELS OF MERCURY IN FISH FROM REGION 4, NATIONAL PESTICIDES
MONITORING PROGRAM, 1969,a 1970,a AND 1972b
Concentration, ppm
Location
Alabama
Alabama River
Tombigee River
Arkansas
Arkansas River
White River
Florida
Apalachikola River
St. John's River
St . Lucie Canal
Suwannee River
Georgia
Altamaha River
Savannah River
Louisiana
Mississippi River
Red River
Mississippi
Yazoo River
North Carolina
Cape Fear River
Roanoke River
South Carolina
Cooper River
Pee Dee River
Tennessee
Cumberland River
Mississippi River
Tennessee River
1969
0.46
0.12
0.21
0.16
0.05
0.23
0.60
0.16
0.23
0.11
0.12
0.16
Mean
1970
0.36
0.44
0.14
0.19
0.11
0.18
0.18
0.22
0.28
0.78
0.14
0.18
0.16
0.37
0.14
0.16
0.47
0.10
0.21
0.45
1972°
0.136
0.33
0.13
0.17
0.10
0.06
0.07
0.17
0.31
0.46
0.11
0.15
0.17
0.18
0.10
0.16
0.24
0.17
0.11
0.39
1969
0.36-0.65d
0.08-0.15
0.13-0.27
0.08-0.23
<0. 05-0. 08
0.13-0.34
0.36-1.00d
0.11-0.22
0.17-0.35
0.09-0.13
0.09-0.14
0.09-0.27
Range
1970
<0.05-0.60d
0.15-0.92d
0.09-0.22
0.12-0.35
0.10-0.13
<0. 05-0. 43
0.06-0.28
0.13-0.37
0.11-0.51
0.17-1.80d
<0. 05-0. 30
0.10-0.24
0.10-0.19
0.25-0.60
0.08-0.21
0.05-0.24
0.19-1.00
0.05-0.15
0.14-0.46
0.27-0.67
1972
0.04-0.36
0.01-0.96d
0.06-0.16
0.11-0.27
0.05-0.19
0.03-0.10
0.06-0.16
0.07-0.49
0.11-0.54
0.14-0.67d
0.06-0.16
0.08-0.18
0.15-0.27
0.10-0.40
0.04-0.23
0.01-0.28
0.10-0.36
0.04-0.34
0.05-0.20
0.22-0.78
, Source: Henderson et al., 1972.
Source: Berger, 1974.
^Calculated from author's data.
Largemouth bass.
2-51
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TABLE 2.25. LEVELS OF MERCURY IN FISH FROM REGION 5, NATIONAL PESTICIDES
MONITORING PROGRAM, 1969,a 1970,a AND 1972b
Location 1969
Connecticut
Connecticut River 0.36
Maine
Kennebee River
Penobscot River 0.38
Maryland
Potomac River 0.09
Susquehanna River 0.07
Massachusetts
Merrimac River
New Jersey
Delaware River 0.12
Raritan River
New York
Genessee River 0.20
Hudson River 0.20
Lake Ontario 0 .52
St. Lawrence River
Pennsylvania
Allegheny River
Lake Erie 0.13
Vermont
Lake Champlain
Virginia
James River
Kanawha River <0.05
Mean
1970
0.34
0.66
0.48
0.05
0.07
0.25
0.11
0.21
0.24
0.13
0.84
0.27
0.12
0.31
0.41
0.14
0.06
Concentration ,
1972C 1969
0.21 0.13-0.80d
0.63
0.56 0.23-0.48
0.21 0.08-0.10
0.07 0.05-0.09
0.39
0.11 0.05-0.22
0.18
0.08 0.13-0.25
0.14 0.16-0.25
0.32 0.43-0.65
0.14
0.07
0.13 0.10-0.15
0.36
0.07
0.04 <0.05
ppm
Range
1970
0.18-0.51
0.38-1.20°
0.29-0.64
<0. 05-0. 09
0.05-0.10
0.15-0.33
0.07-0.21
0.08-0.29
0.15-0.39
0.07-0.19
0.30-1.30d
0.18-0.39
0.05-0.18
0.15-0.43
0.27-0.49
0.11-0.20
<0. 05-0. 11
1972
0.12-0.32
0.23-0.99f
0.49-0.62
0.06-0.36
0.03-0.10
0.09-0.56
0.02-0.18
0.10-0.28
0.07-0.11
0.12-0.15
0.24-0.47
0.08-0.24
0.04-0.09
0.04-0.16
0.24-0.50
<0. 05-0. 12
0.01-0.06
.Source: Henderson et al., 1972.
Source: Berger, 1974.
.Calculated from author's data.
White perch.
-Yellow perch.
Bass.
2-52
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TABLE 2.26. LEVELS OF MERCURY IN FISH FROM REGION 6, NATIONAL PESTICIDES
MONITORING PROGRAM, 1969,a 1970,a AND 1972b
Location 1969
Colorado
Arkansas River
Rio Grande River
Iowa
Des Moines River
Kansas
Kansas River
Missouri
Missouri River
Montana
Big Horn River
Missouri River 0.14
Yellowstone River
Nebraska
Missouri River <0.05
North Platte River
Platte River
South Platte River
North Dakota
Missouri River 0.19
South Dakota
James River
Utah
Green River <0.05
Utah Lake 0.05
Mean
1970
0.06
0.13
0.17
0.18
0.11
0.26
0.19
0.11
0.14
0.11
0.14
0.10
0.17
0.14
0.18
0.04
Concentration,
1972C 1969
0.04
0.09
0.06
0.05
0.08
0.11
0.24 0.13-0.14
0.12
0.11 <0. 05-0. 07
0.21
0.14
0.23
0.11 0.13-0.30
0.16
0.13 <0. 05-0. 10
0.01 <0. 05-0. 06
, ppm
Range
1970
0.05-0.07
<0. 05-0. 28
0.07-0.24
0.08-0.33
<0. 05-0. 15
0.18-0.35
0.13-0.24
0.08-0.15
0.06-0.20
0.09-0.14
0.11-0.24
0.08-0.15
0.11-0.24
0.08-0.22
0.14-0.24
<0. 05-0. 07
1972
0.04-<0.05
0.05-0.14
0.03-0.09
0.02-0.07
0.04-0.13
0.04-0.16
0.10-0.50
0.05-0.17
<0. 05-0. 20
0.16-0.23
0.11-0.20
0.11-0.34
0.02-0.18
0.10-0.22
0.03-0.20
0.01-0.02
Source: Henderson et al., 1972.
Source: Berger, 1974.
°Calculated from author's data.
2-53
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Ul
-p-
7
0.005-0.017
0.017-0.481
0.003-0.582
0.026-0.457
(offshore)
.000-0.016
000-6.983
.014-0.228
084-0.117
.010-0.398
0.005-0.991
0.044-0.104
0.001-1.511
0.003-3.573
Figure 2.7. Levels of mercury ±n fishes, National Marine Fisheries
Service Microconstituent Resource Survey (in ppm,.wet
weight—range of means)(National Marine Fisheries
Service, 1975).
-------
snapper. An additional eight species were found to have mean values greater
than 0.5 ppm. Highest concentrations were found along the southeastern
coast line, particularly along North Carolina and Florida. Elevated values
were also found near Galveston Bay, Texas; San Diego, California; Protection
Island, Washington; and Hawaii.
Areas of known or suspected mercury contamination have been the sites
of many localized investigations of the mercury levels in fish tissue. The
most heavily studied include sites of industrial pollution such as the
Columbia and Savannah Rivers and the Great Lakes (Buhler et al., 1973;
Buhler, 1977; Roberts et al., 1975; Kelso and Frank, 1974; Pillay et al.,
1972; Greig and Seagran, 1972) as well as locations where contamination is
due to either natural leaching of soils or mining activity, such as in the
Columbia and Snake River systems and Lake Powell, Arizona (Blinn et al.,
1974; Buhler et al., 1973; Buhler, 1977; Potter et al., 1975). Two states,
Ohio and Wisconsin, have been extensively surveyed in comprehensive studies
(Stiefel, 1975; Kleinert and DeGurse, 1972).
Incidences of excessive contamination also occurred in Lake St. Clair,
Michigan (Greig and Seagran, 1972; Bails, 1972), Lake Erie (Carr et al.,
1972; Greig and Seagran, 1972; Pillay et al., 1972; Stiefel, 1975), Lake
Michigan (Kleinert, 1972; Kleinert and DeGurse, 1972), and Cranberry Lake
in New York (Roberts et al., 1975). Lowest levels found were in fishes
from the Great Smokey Mountains in North Carolina, with mean values less
than 0.05 ppm (Huckabee et al., 1974; Huckabee, 1972).
Consistently elevated levels of mercury reported in localized marine
fish studies were found on the Atlantic coast in Massachusetts' offshore
waters (Greig et al., 1975) and particularly along the South Carolina-
Georgia coastal region (Stickney et al., 1975; Reimold and Shealy, 1976).
Elevated concentrations were found in other areas also but usually in a
single species, i.e., blue marlin near Hawaii (Rivers et al., 1972;
Shultz et al., 1976), spiny dogfish off the coast of Oregon (Childs and
Gaffke, 1973, and starry flounder in Puget Sound, Washington (Buhler et al.,
1973). Sources of contamination along the Atlantic coast appear to be
industrial (Roberts et al., 1975), whereas in Hawaii and Puget Sound the
elevated levels are likely due to natural phenomena (Schultz et al., 1976;
Buhler, 1977; Buhler et al., 1973).
Although there are wide variations in mercury content among sampling
locations, the literature indicates that overall concentrations of mercury
found in fish tissue are slightly higher in freshwater fishes. This may
be due, in part, to the greater dilution and dispersion capacity of oceans
and the far-ranging habits of most large ocean species. There is some
evidence favoring these hypotheses in the lower concentrations found in
fishes from offshore north Atlantic waters and in the Pacific Northwest
(Greig et al., 1975; Buhler, 1977).
Fish in reservoirs contain higher levels than those collected upstream
in free-flowing sections of rivers (Gebherds et al., 1971; Buhler, 1977).
Apparently, deposition of sediments rich in mercury in reservoirs provides
2-55
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an opportunity for maximum bacterial formation of methylmercury, which is
then readily accumulated by fish.
In both the freshwater and marine studies, there is much evidence that
mercury accumulates through the aquatic food chain, resulting in highest
concentrations in the muscle tissues of those species at the top of the
trophic structure, the piscivores (Buhler, 1977; Potter et al., 1975;
Roberts et al., 1975; Pillay et al., 1972; Stiefel, 1975; Walter et al.,
1973; Gardner et al., 1975; Peterson et al., 1973). There are a few
studies where no indication of bioaccumulation was statistically detected
(Greig et al., 1975; Knauer and Martin, 1972; Huckabee et al., 1974).
However, the study by Knauer and Martin utilized relatively small sample
sizes and that by Huckabee et al. investigated an area of extremely low
environmental mercury levels.
Mercury concentration increases with fish weight, length, and age
(Kelso and Frank, 1974; Mathis and Kevern, 1973; Knight and Herring, 19725
Richins and Risser, 1975; Peterson et al., 1973; U.S. Senate, 1971).
Between 61 and 100 percent of the total mercury found in fishes is present
as methylmercury (Henderson et al., 1972; Buhler et al., 1973; Huckabee et
al., 1974; Gardner et al., 1975; Knauer and Martin, 1972). Tests have
confirmed that significant amounts of a single oral dose of methylmercury
is demethylated in sea lions (Buhler and Mate, 1977). This process probably
occurs in the liver. In addition, if inorganic mercury was released at some
other site, it would tend to concentrate primarily in the kidney in the same
manner as it does in animals that have been dosed with inorganic mercury.
Shellfish
Highest levels of mercury in shellfish are reported on the Atlantic
coast, particularly near offshore Massachusetts and the Brunswick area of
Georgia (Roberts et al., 1975). With the exception of isolated elevated
values in Lavaca Bay, Texas, the lowest values reported in the literature
were found in the Gulf of Mexico (Roberts et al., 1975). At all locations
crabs appeared to have the greatest accumulations. This could be due to
their omnivorous food habits.
Data from the National Marine Fisheries Services Resource Survey
(National Marine Fisheries Service, 1975) report mercury concentrations
in samples of 11 species of mollusks and six species of Crustacea collected
from all coastal U.S. waters. Only two species, brown shrimp and Dungeness
crab, had mean mercury levels greater than 0.1 ppm.
Marine Mammals
Highest mercury concentrations reported in marine mammals from a
rather limited data base were found on the Pacific coast—San Miguel
Island, California (Anas, 1974), and the Oregon coast (Buhler et al., 1975),
in seals and sea lions, respectively.
2-56
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The general literature indicates that various species of marine
mammals were capable of accumulating relatively high tissue concentrations
of mercury (Buhler et al., 1975). Seals and walrus which do not migrate
from the Arctic region generally contain relatively low concentrations of
mercury found in some species of marine mammals, such as California sea
lions, is a consequence of the animals living and feeding in U.S. and
Canadian coastal waters. Mercury concentrations in coastal areas are
known to be higher than those in the open ocean (Jonasson and Boule,
1972; Klein and Goldberg, 1970) as a result of natural and man-related
mercury contamination of the marine environment.
With the possible exception of the sea lion epizootic in 1970,
carnivorous marine mammals consume large quantities of fish and other
marine organisms containing significant amounts of methylmercury with no
apparent ill effect. The presence of inorganic mercury in the liver of
California sea lions and other marine mammals which ingest large amounts
of methylmercury suggests that these animals, and perhaps other species
as well, may have some enzymic or other system for detoxifying methyl-
mercury by converting it to the inorganic form. Studies by Lee et al.
(1977) suggest that a low-molecular-weight protein called methallothionein
may play a protective role in the animals by binding significant amounts
of the mercury present in tissues.
There is some evidence that mercury is accumulated as much as 500+
times the concentration of seawater by organisms inhabiting the sediment-
water interface (Klein and Goldberg, 1970) , and that mercury is transferred
through benthic food chains by much smaller factors (Williams and Weiss,
1973). However, a study by Stickney et al. (1975) showed no positive
correlation between the levels found in invertebrates and those found in
predator fishes.
In order to determine or estimate the environmental distribution of
mercury in aquatic invertebrates in the U.S., studies utilizing similar
organisms and tissues of those specimens from many more locations are
necessary.
Aquatic Plants and Plankton
Few studies have been conducted on the levels of mercury in aquatic
plants and plankton. The data from a study of Lake Powell, Arizona
(Table. 2.27) may be representative of areas of high natural mercury levels
in water (Standiford et al., 1973; Potter et al., 1975). These data show
higher levels of mercury in submerged aquatic plants than in algae, moss,
or periphyton.
A study of salt-marsh grass on the Georgia coast showed that roots
of the grasses accumulate levels of mercury as much as an order of magnitude
greater than those accumulated by other plant parts (Windom, 1973) . Levels
found in phytoplankton ofter appear slightly greater than those in zoo-
plankton (Copeland, 1972; Knauer and Martin, 1972). An investigation by
2-57
-------
Knauer and Martin (1972) measured the methylmercury fractions of wet weight
samples of phytoplankton. Between 12 and 67 percent of the total mercury
content was methylmercury.
TABLE 2.27. LEVELS OF MERCURY IN PLANTS
OF LAKE POWELL, ARIZONA
Organism
Organ
Concentration, ppm wet weight
Mean Range
Nonvascular plants
Algae
Algae, lichen soil crust
Moss
Periphyton, shallow water
Vascular plants
Cattail, Typha latifolia
Green tissue
Green tissue
Green tissue
Green tissue
Leaf and green
0.015
0.023
0.016
0.032
0.036
0.008-0.021
0.014-0.022
0.012-0.020
0.021-0.042
0.025-0.047
Joint-fir, Ephedra sp.
Juniper, Juniperus
osteosperma
Snakeweed, Gutierrezia
microcephala
Unidentified grass
Unidentified shrub
tissue
Leaf and green 0.025
tissue
Leaf and green 0.018
tissue
Stem 0.021
Stem 0.090
Leaf 0.015
Stem 0.039
0.000-0.040
0.019-0.023
0.076-0.104
0.010-0.020
Source: Standiford et al., 1973.
2-58
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3. BEHAVIOR IN THE ENVIRONMENT
Mercury enters the environment through vaporization, volatilization,
weathering, dissolution, precipitation, and biodegradation. Its environ-
mental movement depends on its oxidation state; the redox potential,
temperature, and pH of the environment; solubility; volatility; and the
nature of available chemical species with which it forms strong bonds
(Krenkel, 1974). Transport and transformation data indicate that all com-
ponents of the biosphere contain traces of mercury and constitute potential
sources of exposure for all biota, including man.
Some of the complexities of the behavior of mercury in the environ-
ment include the following characteristics: (1) forms and compounds of mer-
cury in nature, (2) transformation of mercury in nature, (3) the mercury
geochemical cycle, and (4) transport of mercury in the food chain. Emphasis
in this discussion is on those characteristics that influence its persistence
and environmental fate.
TRANSFORMATION IN NATURE
Although mercury exists in nature in its elemental Hg(0), mercurous
Hg(I), and mercuric HG(II) oxidation states, it is readily converted from
one form to another, depending on conditions, according to the dispropor-
tionation reaction, 2Hg(I) J Hg(0) + Hg(II) (Hem, 1970; Jonasson and Boyle,
1971). The stability and solubility of each of these oxidation states is
dependent upon the redox potential, the electrical potential (EL)-pH
relationship, temperature, and the concentration of major ions in solution.
Four basic reactions are involved in the mercury interconversion
cycle (Figure 3.1): (1) conversion of Hg(0) to Hg(II), (2) conversion of
inorganic Hg(II) to methylmercury, (3) conversion of phenyl- to methyl-
mercury, and (4) conversion of alkoxyalkyl to Hg(II) or Hg(0) (Jernelov,
1969; Jonasson and Boyle, 1971)- These reactions permit release of mercury
to enhance its movement in soil, water, sediment, and biota.
Metallic mercury, Hg(0), is somewhat reactive: it can be oxidized or
reduced in the presence or absence, respectively, of oxygen (Hem, 1970).
Its water solubility, 0.02 to 0.03 mg/fc at 20 C is higher for the metal
than for some of its salts (Krenkel, 1974). Metallic mercury has a marked
chalcophile character and, in natural systems, forms sulfides, selenides,
a telluride, and complex compounds with antimony, arsenic, and sulfur
(Jonasson and Boyle, 1971). It is also an oxyphile forming a natural oxide
and a number of oxychlorides and complex hydrous chloride sulfates.
3-1
-------
Bacterial oxidation
Plankton
Plants
Inorganic
reactions
Mercuric ion,
chelated cations and onions,
simple complexes,
oxides, sulphides
Hg(ll)
Bacterial reduction
Fungi
Plant:
Inorganic reactions
Sunlight
Elemental mercury
as vapour, liquid
or dissolute
Hg(0)
Bacteria
Sunlight
^Bacterial reduction
^Fungi
^Plants
Bacterial oxidatiorrv \Jnorganic
Plants >«. ^v^reactions
Inorganic reactions
Bacterial synthesis
Chelation
Bacteria, ^'
conversion by
organic oxidants
fr
%
£• R-Hg-R'
Hg(l)
Bacterial synthesis
Chelation
Organic oxidants
Duproporlionation and
electron exchange
Mercurous ion,
chelated cations and onions,
simple complexes
Organo - mercury
compounds
R, R' = alkyl, aryl,
mercapto,
protein, etc.
X = monovalent anion
eg. halide, acetate,
etc.
Figure 3.1. Cycle of mercury interconversions in
nature (Jonasson and Boyle, 1971).
3-2
-------
ultraviolet radiation lose the ability to methylate mercury and that the
rate of conversion to methylmercury is dependent upon mercuric ion concen-
tration, solution pH, and temperature.
Pathways which have been proposed for methylation of mercury (Jernelov,
1969; Wood, 1971; Katz, 1972; Bisogni and Lawrence, 1973; Rogers, 1975, 1976)
are summarized in Figure 3.2. Several kinetic schemes have been proposed by
Wood (1971) , indicating that most anaerobes and many aerobic bacteria can
synthesize methylmercury. Under anaerobic conditions, both organic and
inorganic mercury compounds are first converted to metallic mercury, then
transformed to methylmercury; under aerobic conditions, metallic mercury
and organic mercury compounds are converted to mercuric ions before methyl-
ation occurs. The formation of methylmercury is predominant at lower pH,
while dimethylmercury is favored at higher pH. Monomethylmercury is mainly
accumulated in living organisms, while dimethylmercury has a tendency to
evaporate to the atmosphere. The released dimethylmercury may break down
under ultraviolet light or acidic conditions to monomethyl- or elemental
mercury and will precipitate over land or water. Monomethylmercury may
convert to dimethylmercury or to volatilizable mercuric ions (Jernelov,
1972).
The rate of biological methylation of mercury appears to be largely
dependent upon the concentration of mercury, the number of methylating
organisms, and physical-chemical parameters including pH, temperature,
and the presence of oxygen and other organic materials. Fagerstrb'm and
Jernelov (1972) found in laboratory experiments that the rate of methyl-
mercury formation in organic sediments is much higher when the oxygen
content in water if low, 0 to 2 ppm. The subsequent uptake by fish is
also higher at low oxygen levels. In natural waters, a higher rate of
methylation can occur under aerobic rather than anaerobic conditions due
to the formation of mercuric sulfide (Jernelb'v, 1972) . Methylation of
mercuric sulfide is not likely to occur under anaerobic conditions; even
under aerobic conditions, it is 100 to 1000 times slower than with mercuric
chloride (JernelBv and Martin, 1975). The rate of mercury methylation under
anaerobic conditions seems to be slow and of less significance ecologically
than that under aerobic conditions (Katz, 1972). When sediments are exposed
to air by the action of tides or by dredging activities, the rate of methy-
lation is higher by orders of magnitude than the normal rate for sediments
under water (Fagerstrb'm and Jernelov, 1972) . Bisogni and Lawrence (1972)
have found the rate of mercury methylation to be much higher in aerobic
systems than in anaerobic systems at a given mercury concentration and
microbial growth rate.
Jacobs and Keeney (1974) found a much higher degree of methylation in
the sediments of the Wisconsin River with low pH and high organic matter
than in the sediments of the Fox River which is characterized by high pH and
low organic matter. Temperature also influences the rate (Fagerstrtim and
JernelSv, 1972). The methylation rate increases with temperature, roughly
following the QiQ-rule (doubled rate when temperature increases 10 C), and
with increased nutrient content in the substrate. The rate is also higher
with suspended material and in the upper layer of sediment than it is
farther down.
3-4
-------
Compounds of Hg(I) are typical of metallic mercury compounds (Krenkel,
1974): (1) all are ionized in solution; (2) most, except for the nitrate and
perchlorate, are only sparingly soluble in water at ordinary temperatures;
and (3) mercurous chloride (HgCl), the most soluble of the halides, occurs
naturally. They are readily oxidized to Hg(II) by strong oxidizing agents.
Salts of Hg(I) undergo disproportionation to give Hg(II) derivatives and
Hg(0). The mercurous ion, Hg(I), does not form covalent bonds with other
elements, and thus organometallic Hg(I) derivatives do not occur.
The mercuric ion, Hg(II), is relatively stable under oxidizing condi-
tions, especially at low pH (Hem, 1970), but can be reduced to Hg(I) or
Hg(0) in a reducing environment (Jonasson and Boyle, 1971; Holm and Cox,
1974). When organic materials are present, divalent mercury will also bind
to them to form organic complexes.
Mercuric mercury, Hg(II), generally forms covalent rather than ionic
bonds, although the nitrate Hg(NC>3)2, sulfate HgSO^, and perchlorate
Hg(C104)2 are true salts (Krenkel, 1974). These compounds are less soluble
in water than in organic solvents. The Hg(II) cation is not a common
species in aqueous media and never constitutes a significant portion of the
total mercury found there.
Carbon bonds more stable with Hg(II) than with Hg(I) (Krenkel, 1974).
Both mono- and diorganomercury (II) derivatives are well known. Alkylmer-
curic compounds are more stable and less volatile but are more mobile
biologically than other forms of mercury (D'ltri, 1972).
The biological conversion of inorganic mercury to organic methyl-
mercury is the key to the distribution, transport, and bioaccumulation of
mercury in the environment (Jensen and Jernelb'v, 1969; D'ltri, 1972). In
aquatic systems, this conversion occurs by two main processes, microbial
(enzymatic) and chemical (nonenzymatic). Enzymatic methylation takes place
in organic sediments and in rotting fish (Jensen and Jernelov, 1969), in
cell extracts of methanogenic bacterium (Wood et al., 1968), in cultivated
bacterium Clostridium (Yamada and Tonomura, 1972), and in fungus Neurospora
(Landner, 1971). Nonenzymatic synthesis of methylmercury from inorganic
divalent mercury occurs under mild reducing conditions with methylcobalamin
and propylocobalamin (Wood et al., 1968). Methylmercury is also formed from
mercuric chloride by a purely abiotic reaction in the presence of methyl-
cobalamin (Imura et al., 1971; Bertilsson and Neujahr, 1971). However,
microbial activity is a prerequisite for methylation in nature unless other
methylmetal compounds are already present in the system (Jernelov and Martin,
1975). Laboratory experiments have shown that mercury methylation also
occurs in the terrestrial environment in soils (Berkert et al., 1974; Rogers,
1975) and in the tissues of peas (Gay, 1976) .
Rogers (1975, 1976) at the EPA laboratory in Las Vegas has found that
the soil transformation of mercury to methylmercury occurs by abiotic as
well as biotic means. He determined that a constituent could be extracted
from soil which would methylate mercuric ion abioticly. The methylating
substance is associated with the lower molecular weight fraction of the
soil organic matter. He also found that soil extracts exposed to
3-3
-------
ATMOSPHERE
U>
(C6H5)2 Hg
Diphenyl Mercury
Phenyl
Mercuric
Ion
CH30-CH2-CH2-Hg
Methoxyethyl Mercury
Hg
Hg
Hg°
Metallic Mercury
-»
enzyme transfer
(anaerobic)
(CH3)2 Hg
Dimethyl Mercury
Mercurous Ion
Mercuric Ion
chemical transfer
(aerobic)
(also abiotic in soil)
CH_ Hg+
j
Methyl Mercury
HgS
Mercuric Sulfide
Figure 3.2.
WATER (SOIL)
Pathways of mercurial breakdown and methylation in nature
(Jernelov, 1969; Wood, 1971; Katz, 1972; Bisogni and
Lawrence, 1973; Rogers, 1975 and 1976).
AQUATIC ANIMALS
-------
Matsumura et al. (1971) found that microorganisms isolated from
mercury-containing soil and lake sediments convert phenylmercuric acetate
to diphenylmercury but observed no methylmercury derivatives after 10-day
incubations. During long-term, 50 days, incubation of lake sediments
containing inorganic mercury, Spangler et al. (1973) observed a buildup
of low concentrations of methylmercury, up to 0.3 yg/g sediment. There was
a rapid decrease in the amount of methylmercury due to microbial degrada-
tion followed by the evolution of elemental mercury, suggesting that the
net amount of methylmercury accumulation in the sediment would be minimal.
Degradation of methylmercury has been observed in cultures of bacteria
Pseudomonas (Tonomura et al., 1968), in rats (Norseth and Clarkson, 1970),
and in the guinea pig (Iverson and Hierlihy, 1974) .
GEOCHEMICAL CYCLE OF MERCURY
The processes by which mercury is transportated through the geochemical
cycle are shown in Figure 3.3 (Jonasson and Boyle, 1971). Because of its
high vapor pressure, even at normal temperatures, elemental mercury rapidly
vaporizes from rocks, soils, and waters into the atmosphere. At room
temperature, the saturation concentration of mercury in air approaches 15
mg/m3 (Vostal, 1972). Mercury is also released to the atmosphere by
volatilization, chemical or microbial reduction, and biological methylation.
Solubility is a major factor in the natural distribution of mercury.
Practically all mercury in air disappears immediately after a rainstorm,
even in areas of higher concentration such as near ore deposits (McCarthy
et al., 1970). Despite a tendency to sorb on soil, plants, or animals or
to complex with other organic materials and minerals, mercury compounds are
translocated within the soil or into the hydrosphere by surface runoff,
groundwater, or geothermal springs. Weathering and sedimentation are the
major pathways for the natural flux of mercury between land and the oceans.
The summation of available data on the global cycling of mercury from
natural and man-made sources indicate that the total release of mercury in
nature due to weathering and vaporization amounts to 20,000 to 40,000 metric
tons per year, while man's activitiy contributes an additional 5,000 to
10,000 metric tons per year (Table 3.1) (Hammond, 1971; Dickson, 1972;
Wollast et al., 1975). While these data may be open to question, they
suggest that man's activity could increase the natural flux by up to 60
percent.
The residence times of mercury in the four available reservoirs
(Wollast et al., 1975) are reported as:
Reservoir Time
Land 1,000 years
Atmosphere 60 days
Ocean 32,000 years
Sediments 2.5 x 108 years
3-6
-------
1
DEGRADATION
1
I
1
! ATMOSPHERE
i
i
c
^Py^DE
/
_ EXHALATION
PRECIPITATION
BIOSPHERE
Plants ^»^ Animals
C/tGkAD/-T|( )N
1 + Vo
GRADATION ABSORPTION ^\^o
AND AND <3snVr'<
SOLUTION ADSORPTION ^ftoV'
i I % 1
HYDROSPHERE
Water ^^ Sediments
i t
CHEMICAL PRtCll'ITATIOrJ , (- . r,-)N,
AND SEDIMENTATION ',",,^'J;N
OF SOLIDS ' ' ' ,,
, WtAlHtfh
f I
EXHALATION
HEMICAL
PRECIPITATION
LiTHnSPHEPE i
PRECIPIIAilON |
*" FhDUbPhckL-
Sors
SOLUTION /-., • i ,. . ,
1
1
VND
Al
slG
OOlUTlON AND
Mr.CHA-'.lCAL
WEATh: y.M'S
ftoc^s !
Mercury Deposits ___ ;/f tGfVAiiON A^aJ
voKANK.pHtNov.FNA * TONSOl , ! ; A T ION OF SOI IDS
Figure 3.3. Generalized geochemical cycle of mercury
in natural systems (Jonasson and Boyle, 1971).
3-7
-------
TABLE 3.1. GLOBAL CYCLING OF MERCURY
(metric tons/year)
I
oo
Man's Activity
Natural Flux
Weathering
230
3,800
2,500
4,000
5,000
Vaporization
NAa
>25,000
NA
36,000
25,000
Industrial Wastes
3,000
5,800
NA
NA
5,000
Fossil Fuel
Combustion
(Coal and Oil)
3,000b
1,600
1,600
3,000-5,000
5,000
Total Flux Reference
Joensuu, 1971
36,000 Weiss et al., 1971
Bertine and Goldberg,
1971
43,000-45,000 Marton and Marton, 1972
40,000 Wollast et al., 1975
NA = Not available.
Coal only.
-------
The tentative present-day geochemical cycle of mercury in the biosphere is
shown in Figure 3.4.
Total flux to atmosphere
408
1 1
LAND
gain 23
/
\
Rivers
50
\ f
^ OCEAN
gain 64
/
90
M UPLIFT"
32
EXPOSITION
35
MINING
SEDIMENTS
lOSS 87
Figure 3.4. Tentative present-day cycle of mercury (reservoir
changes and fluxes in units of 102 MT/yr). [Reprinted
from Ecological Toxicology Research (A. D. Mclntyre
and C. F. Mills, editors) by R. Wollast, G. Billen,
and F. T. Mackenzie by permission of Plenum Publishing
Corporation. Year of publication 1975.]
Air Transport
Mercury is readily emitted to the atmosphere due largely to its
volatility and high vapor pressure. Presumably, in the U.S., over 500
metric tons of mercury are emitted to the atmosphere each year from man's
activity (Holt et al., 1975). Mercury and its compounds are dispersed in
air by wind and are deposited on land and water by dry precipitation,
rainfall, and snowfall. However, the mode of transport and fate of this
pollutant are not clearly understood.
The ambient forms of mercury in air include particulates, mercuric
chloride-type compounds, methylmercury (II-type compounds), elemental
mercury, and dimethylmercury (Braman and Johnson, 1975). Vapors tend to
concentrate by adsorption on dust particles (Williston, 1968) and, together
with the other particulates, are removed by dry fallout, rain, and snowfall
(Jenne, 1970) . The saturation concentration of mercury in air amounts to
10 to 15 mg Hg/m3 at room temperature (Vostal, 1972).
While the rate of mercury release into the atmosphere is determined
mainly by barometric pressure, its distribution and transport are largely
controlled by wind, rainfall, and snowfall, seasonal variations in
temperature, and other natural and meteorological laws (McCarthy et al.,
3-9
-------
1970). Williston (1968) found higher, nearly double, mercury concentrations
in summer than in winter in the San Francisco Bay area. Diurnal variations
have also been observed (McCarthy et al., 1970). Generally, the greatest
amounts are found at midday, while minimum concentrations are observed in
the morning and evening when the rate of increase in barometric pressure is
high. Higher mercury readings have been observed on cloudy and foggy days
than on normal days, yet no clear correlation has been found between
humidity and mercury content of the air. Elevated atmospheric concentra-
tions of mercury also have been observed on smoggy days (Krenkel and
Goldwater, 1973; Williston, 1968). Cool, wet weather generally results in
lower than average mercury readings, whereas the reverse is true for warm,
dry weather. However, the daily maximum mercury reading does not neces-
sarily coincide with the daily maximum temperature (McCarthy et al., 1970).
More mercury is found in the air of mercury mines and mineral
deposits than elsewhere (McCarthy et al., 1970). However, the dependence
of mercury content on the distance from a source is more likely a function
of mercury species and the prevailing wind. In studies around sewage plants
in Washington, D.C., and Memphis, Tennessee, the concentration of elemental
mercury in air decreased sharply with increasing distance from the source,
while the organic mercury forms increased almost logarithmically with
distance up to at least 16 km (10 mi) (Soldano et al., 1975). This suggests
that the alkylmercury compounds can be spread over a broad area and long
distance from the source, a phenomenon which is enhanced by the prevailing
wind direction and velocity in the area (Anderson and Smith, 1977) .
The vertical distribution of mercury in air appears also to be a
function of altitude (McCarthy et al., 1970). Maximum levels above the soil
surface near mercury mine areas are reportedly nearly 200 times greater than
those found at 122 m (400 ft) above the ground (Table 3.2). This altitude
effect is much less significant in nonpolluted areas and varies according
to seasonal/temperature differences (Williston, 1968). Williston (1968)
suggests that mercury is uniformly distributed in soil throughout the
United States by wind action as well as by rainfall and snowfall.
Soil Transport
The mercury concentration of soil varies significantly at different
locations. In addition to the naturally occurring mineral deposits, large
quantities may be deposited from the atmosphere and a lesser amount may be
added by agricultural applications such as pesticides and seed treatments.
Factors influencing the mercury content of soils include pH, drainage
composition, concentrations of humus, and microbial activity. Mercury
compounds may convert to soluble or volatile forms by geochemical and
biological actions within the soil. Metallic mercury may be readily
volatilized or converted to mercuric sulfide or, due to its high affinity
for organic matter, to organic mercury compounds. Thus, the accumulation
of mercury in soil may be related to the total sulfide and organic carbon
levels (Lagerwerff, 1972).
3-10
-------
TABLE 3.2 MAXIMUM MERCURY CONCENTRATION IN AIR MEASURED AT
SCATTERED MINERALIZED AND NONMINERALIZED AREAS
OF THE WESTERN UNITED STATES
Maximum Concentration, ng/m3
Ground 122 m (400 ft)
Sample Location Surface above ground
Mercury Mines
Ord mine, Mazatzal Mtns., Arizona 20,000 (50)b 108 (4)
Silver Cloud mine, Battle Mtn., Nevada 2,000 (50) 24 (8)
Dome Rock Mtns., Arizona 128 (6) 57 (20)
Base and Precious Metal Mines
Cerro Colorado Mtns., Arizona 1,500 (5) 24 (2)
Cortez gold mine, Crescent Valley, Nevada 180 (60) 55 (4)
Coeur d'Alene mining district, Wallace, Idaho 68 (40) NA
San Xavier, Arizona NA 25 (3)
Porphyry Copper Mines
Silver Bell mine, Arizona NA 53 (3)
Esperanza mine, Arizona NA 32 (3)
VekolMtns., Arizona NA 32 (4)
Ajo mine, Arizona NA 30 (3)
Mission mine, Arizona NA 24 (3)
Twin Buttes mine, Arizona 20 22 (3)
Pima mine, Arizona NA 13 (3)
Safford, Arizona NA 7 (2)
Unmineralized Areas
Blythe, California NA 9 (20)
Gila Bend, California NA 4 (2)
Salton Sea, California NA 3.5 (2)
Arivaca, Arizona NA 3 (2)
Source: McCarthy et al., 1970.
aSamples taken from single-engine aircraft.
Number of measurements shown in parenthesis.
CNA - Not available.
3-11
-------
A linear relationship exists between humic acid and mercury content in
soil (Trost and Bisque, 1972). Humus-rich soil also increases the solubility
of inorganic mercury compounds, such as mercuric sulfide, mercuric oxide, and
mercurous chloride, above their normal levels. Over 1,000 ng of mercury have
reportedly been absorbed on 1 g of organic matter in soil (Andersson, 1967;
Eriksson, 1967). This reaction is enhanced at lower pH.
Moisture affects the vaporization of mercury compounds at the soil
surface; vaporization decreases with increasing soil moisture (Williston,
1968; Kimura and Miller, 1964).
Although they are more chemically stable, methylmercury compounds are
not bound as firmly to soil or other organic mercury compositions. Aryl and
alkoxyalkyl mercury salts decompose more readily in soil and liberate ionic
and/or metallic mercury (Rissanen and Miettinen, 1972) . Up to 16 percent of
phenylmercury acetate and 32 percent of ethylmercury acetate may volatilize
as metallic mercury vapor in 28 days and 53 days, respectively (Kimura and
Miller, 1964). Methyl derivatives are volatilized as methylmercury at a
rate of 6 to 14 percent in 35 days without decomposing to metallic mercury
vapor. From 51 to 53 percent of methylmercury dicyaniamide added to soil
may be retained after 5 months (Saha et al., 1970).
In microcosms, 139 days after the application of 2Q3Hg, Huckabee and
Blaylock (1974) reported that 50 percent of the total 203Hg remained in the
terrestrial system and 50 percent reached the aquatic system. About 90 to
97 percent of the mercury in the terrestrial system was bound to the soil;
only 3 to 7 percent was retained on the litter and less than 1 percent
absorbed by plants. Old field ecosystem studies have indicated that nearly
80 percent of 203Hg applied to soil is retained at the end of the growing
season (4 months) (Matti et al., 1975). The amount of mercury increases
with time, and more than 90 percent is confined in the top 3 cm of the
column. Levels of mercury in plants bear little relationship to soil
levels since most plants grown in mercury-treated soils accumulate such
small amounts (Smart, 1968; Blanton et al., 1975).
Water and Sediment Transport
Much of the mercury entering surface waters is rapidly adsorbed or
bound to suspended materials and living organisms (Jenne, 1970). Acidity
is important for the degree of binding. Mercury solutes introduced into
streams are quickly transformed to particulates by reduction to metallic
mercury, sorption onto inorganic sorbates, complexation with nonviable
particulate organics, and sorption and ingestion by biota. The majority
of all forms of mercury in water accumulate in the bottom sediment
(Vostal, 1972). In groundwaters, the bicarbonate content is directly
related to mercury concentration (Jenne, 1970).
The mobility of mercury in water is mainly determined by the presence
and amount of organic materials and suspended sediments and the occurrence
of redox conditions (Jenne, 1970). Elevated levels of dissolved organic
3-12
-------
materials may increase mercury mobility. A high percentage of mercury
introduced into streams is removed as sediment and associated fine-grained
materials. Reducing conditions may increase mercury mobility by causing
the dissolution of manganese and iron oxides and by releasing sorbed
mercury to be available for complexing with other organics; they may also
decrease mercury mobility by reducing a significant amount of mercury
compounds to metallic mercury which will then amalgamate with iron oxides
or fall to the bottom. Mercury becomes relatively immobile in reducing
sediments and precipitates as mercuric sulfide (cinnabar). However, at
high pH or under strongly reducing conditions, mercuric sulfide anions may
become very soluble.
Chlorides may also affect the release of mercury from bottom
sediments. The use of CaCl2 and NaCl for deicing roads increases the
relative amount of mercury in water in equilibrium with sediments by 2 to
5 orders of magnitude (Feick et al., 1972). The changes in pH associated
with the addition of these salts may increase mercury mobility.
The transport and deposition of mercury in estuaries is largely
governed by interactions with natural organic matter (Lindberg and Harris,
1974). In the estuaries of the Gulf of Mexico, approximately 54 to 82
percent of the total dissolved mercury is associated with fulvic acid-type
materials. Decomposition of estuarine vegetation results in detritus
enriched in mercury. Thus, in the Gulf of Mexico, mercury in estuarine
sediments is not significantly redistributed by postdepositional processes.
Windom (1976) reported that only 14 percent, 0.5 x 103 kg/yr, of the
mercury transported by several southeastern U.S. rivers is in particulates,
while the majority, 2.7 x 103 kg/yr, is in soluble form. However, more
than 95 percent of the total mercury in the Walker Branch streams in
Tennessee is in suspended forms. The contribution to total transport of
mercury by suspended sediments is approximately 45 percent, while about
55 percent is due to dissolved mercury (Andren et al., 1975).
Up to 62 percent of the mercury present in surface sediments is bound
to sulfur-containing organic and inorganic particles, clays, and minerals
(Stopford and Goldwater, 1975). In deeper sediments, more mercury, up to
75 percent, is bound to organic acids. Only a small portion of this mercury
is released to water. Simulated dredging results in a slight increase in
the total dissolved mercury in overlying water because of the mixing of
sediment with water and short-term release of the mercury associated with
particulate materials (Lindberg and Harris, 1974).
Sedimented mercury can be released by biological methylation processes,
Methylated mercury is quickly absorbed by living organisms or bound to
inorganic suspended particulates, or it may be rapidly photodegraded to
inorganic mercury and escape to air. Therefore, methylation processes
facilitate mercury transport not only by releasing mercury from sediments
to water and air but also by movement within the food chain. However,
they may not play a major role in the postdepositional migration of mercury
in sediments (Andren and Harris, 1973). Stopford and Goldwater (1975) and
Windom et al. (1976) found little or no methylmercury in the sediments.
3-13
-------
Although Windom et al. (1976) detected a significant level of methylmercury
in the dominant primary consumers of the estuarine ecosystem, the estimated
annual methylmercury conversion was only about 50 ng/g of the total mercury
in the upper 5 cm of the sediment column. This indicates that methylation
is an inefficient mechanism for transferring mercury out of salt marsh
sediments. Methylation of mercury is entirely restricted to the surface of
the sediment with no macrofauna present (Jernelov, 1970). If sediment-
dwelling organisms are present at high densities, the release of mercury by
methylation may occur in sediment at depths to 9 cm.
A study of the mechanisms for mercury transformations affecting
mobility in Par Pond at the Savannah River in Georgia has shown that the
reduction of mercury to its elemental form within a sedimentary environ-
ment is accomplished by humic acids serving as an extracellular electron
transport mechanism (Schindler et al., 1975). The mercury not liberated
from sediments by this mechanism is retained by the organic macromolecules
and alkylated to methylmercury. This mechanism, however, accounts for
only a small portion of the mercury in the system. The electron transport
capacity of the organic ligands may be blocked by calcium, clays, or other
cations and effectively suppress the alkylation/reduction potential of the
sediment.
FOOD CHAIN TRANSPORT
Most aquatic organisms can accumulate mercury in their tissue.
Concentration factors of mercury in edible aquatic organisms are 3 to 5
orders of magnitude greater than background levels (Thompson et al., 1972)
(Table 3.3). The concentration by plants and fish appears to be at the
same level of magnification, but uptake by aquatic invertebrates is much
greater, reaching up to 100,000 times the surrounding water level. Since
invertebrates are not at the top of the food chain, it can be assumed
that the biological magnification of mercury could be a function of the
particular species in the trophic level. However, the levels of mercury
in general increase with increasing trophic level (Table 3.4). Mean
mercury levels in predators are nearly 15 times greater than those in
algae eaters. Aquatic organisms accumulate mercury compounds directly
from ambient water and from their food. They absorb both inorganic and
organic methylmercury compounds.
Neither uptake routes nor the relative importance of mercurials in
food chain accumulation and transport have been fully quantified. The fact
that methylmercury compounds are the predominant form of mercury in aquatic
organisms even though methylmercurials are never found in abundance in
water indicates that mercury in aquatic organisms is accumulated mainly
through the food chain (Huckabee and Goldstein, 1975). A series of
laboratory experiments has shown that methylmercurials have a higher
assimilation efficiency and longer biological half-life than inorganic and
other organic forms of mercury. Species differences in biological half-
lives of methylmercury exist even within various fish species living in
the same environment (Vostal, 1972). The rate of mercury uptake through
the food chain is higher in the top predator fish (60 percent for pike)
3-14
-------
TABLE 3.3. CONCENTRATIONS (IN PPM WET WEIGHT) AND CONCENTRATION FACTORS
OF MERCURY IN WATER AND EDIBLE AQUATIC ORGANISMS
Media
Mercury
Concentration
Concentration
Factor
Sea water 3.0 x 10
Marine plants 3.0 x 10
Marine invertebrates 1.0 x 10
Marine fish6 5.0 x 10
Freshwater 1.0 x 10
Freshwater plants 1.0 x 10
Freshwater invertebrates 1.0 x 10
Freshwater fish 1.0 x 10
-5
-2
0
—2
i
-4
-1
-1
1.0 x 10'
3.3 x 104
1.7 x 10"
1.0 x 10"
1.0 x 10"
1.0 x 10"
Source: Thompson et al., 1972.
Concentrations in edible portions, e.g., muscle and soft parts;
concentration factor determined by dividing the concentration
, in the organixm by the concentration in water.
Representative values for the continental shelf and estuaries,
not for open ocean.
.Exclusive of phytoplankton.
Molluscs and crustaceans.
/~\
Edible portion only, not whole fish.
TABLE 3.4. BIOLOGICAL MAGNIFICATION OF MERCURY IN THE AQUATIC FOOD CHAIN
Organisms
Algae eaters
Zooplankton eaters
Omnivores
Detritus eaters
Predators
Number
of
Samples
39
9
9
12
25
Concentration, ppm
Range
0.01-01.8
0.01-0.07
0.04-1.16
0.13-0.59
0.01-5.82
Arithmetic
Mean
0.05
0.04
0.45
0.54
0.73
More Numerous Organisms
Zooplankton, snails,
mayfly nymphs
Insect larvae, minnows
Insect larvae and adults,
scuds
Worms, clams, insect
larvae
Insect larvae and adults,
frogs
Source: Bligh, 1971,
3-15
-------
and relatively lower for bottom feeders (less than 25 percent) (Jernelb'v and
Lann, 1971)- Thus it appears that direct uptake of mercury from water is
more important in lower trophic level organisms, while the food chain is
the main route of uptake in higher level organisms. Direct accumulation
of mercury compounds from water is similar for both feeder types.
Information on the mercury content of aquatic organisms is extensive,
but the vast majority of the data are presented as total mercury instead
of as the methylmercury form. Information needed to clarify the actual
food chain transport mechanism for mercury is therefore greatly impaired.
Bioaccumulation through the terrestrial food chain appears to be less
significant to man than the aquatic food chain since the main route is
dressed seed -> game birds -> man (Rissanen and Miettinen, 1972). Other
terrestrial routes are much less obvious and require further study.
3-16
-------
4. OCCURRENCE OF MERCURY IN FOOD
MERCURY LEVELS IN FISH
The major dietary source of mercury for many humans is fish and shell-
fish. Birke et al. (1972) concluded from a study of human exposure to
methylmercury through fish consumption that this source contributes at least
half of the mercury intake among fish eaters. Mercury concentrations in
blood cells were approximately twice the concentration found in the blood of
persons who did not eat fish, further confirming the importance of fish
consumption as a critical determinant of mercury intake. Per capita fish
consumption in the United States averages only 18 g per day; comparable
values for Swedes and Japanese are 56 and 88 g per day, respectively
(Hugunin and Bradley, 1975).
Following the Canadian Food and Drug Administration's closure of
Lake St. Clair (an international boundary lake) to commercial fishing in
March, 1970, and subsequent discovery that game fish in Lake St. Clair,
Michigan, had up to 7.0 ppm mercury and in Lake Champlain, Vermont, up to
2.5 ppm, the U.S. Food and Drug Administration Compliance Program was
initiated (Schroeder, 1974). Serious mercury contamination was found in
25 rivers and bays in 11 states. Of 763 composite samples of fish, nearly
90 percent showed mercury levels below 0.5 ppm. The highest mercury levels
were consistently observed in tuna.
To determine the extent of the problem, the entire canned tuna supply
of the United States was analyzed (Kolbye, 1972). Results disclosed that
less than 4 percent of the tuna examined exceeded FDA's administrative
guideline for 0.5 ppm mercury. A similar sampling program for swordfish
revealed that less than 5 percent of the swordfish samples were within the
0.5 ppm guideline and 53 percent exceeded 1 ppm (Clark, 1973). In May,
1971, a public warning was issued against the consumption of swordfish.
Since 1971, all swordfish offered for sale in the United States are examined
for mercury and sold only after individual fish certification (Kolbye, 1972).
In 1971, FDA also conducted an extensive analysis program of the 19
most commercially important fish. The mean mercury level in saltwater fish
was approximately 0.09 ppm; however, mercury concentration in a number of
fish of certain species, such as snapper, bonito, and mackerel, were above
the 0.5 ppm level. Seizure or recall actions were initiated against 14
lots of snapper and 3 lots each of bonito and mackerel out of over 1,000
lots examined. Other predatory fish have been implicated also but not in
commercially significant quantities (Kolbye, 1972).
4-1
-------
Swedish studies have indicated that fish caught in inland waterways
and coastal waters often have much higher levels of mercury than deep sea
fish, suggesting the etiologic role of mercury-containing industrial
effluents in causing excessive mercury uptake in fish from these waters
(Hugunin and Bradley, 1975). Although average levels of mercury in fish
seem difficult to assess, the most significant sources of variation relate
to species, diet, age, size, metabolic rate, and habitat (Hugunin and
Bradley, 1975). Table 4.1 represents a condensation of data presented by
Peyton et al. (1975) grouping fish according to nominal mercury content.
Examining the mercury content of commercial canned shrimp, oysters,
clams, salmon, tuna, anchovies, cat food, and others, Hall (1974) obtained
values for "percent methylmercury" that are in .general agreement with those
of several similar studies reported in the literature reviews by Hugunin
and Bradley (1975) and D'ltri (1972) (Table 4.2).
In a study of fish from waters of the southeastern United States
which were suspected of being polluted by the chlor-alkali industry,
Granade (1972) concluded that a serious mercury problem exists in this
area and that mercury poisoning could result from a consistent diet of
fish caught from certain parts of the rivers. The mercury levels reported
by Granade (1972) include the highest values reported in Table 4.3.
Follow-up studies are not available to evaluate the degree to which
pollution continues in these systems.
Henderson and Shanks (1973), reporting the results of a nationwide
monitoring program conducted by the U.S. Bureau of Sport Fisheries as part
of the National Pesticides Monitoring Program, found the highest residues
were reported in fish from the Columbia, Snake, Salmon, Rouge, and
Truckee rivers; the lowest levels were in fish from Alaskan streams and
the Colorado River (Table 4.3). Eleven samples exceeded the FDA action
level of 0.05 ppm; however, this is significant only in those fish
destined for human consumption. Not all the species sampled in this
program would normally be eaten (Henderson and Shanks, 1973). Van Meter
(1974) , focusing on the evaluation of concentrations of mercury in muscle
tissue of game fish, studied the "effective" measure of exposure in terms
of human dietary dosage. He reported that tissue concentrations of mercury
were low in fish from most of the Upper Clark Fork River region of Montana,
an area noted for diverse mining operations. Consistently higher mercury
levels were found in fish taken from Flint Creek which is fed by several
tributaries from a mining district (Table 4.3).
MERCURY LEVELS IN FOODS EXCLUDING FISH
Although the high levels of mercury in fish and seafoods indicate that
these sources potentially contribute a majority of mercury intake, examina-
tion of mercury levels in nonfish commodities is important because:
(1) Fish and shellfish represent a relatively insignificant
portion of the average American diet.
4-2
-------
TABLE 4.1. SUMMARIZATION OF FISH TYPE BY TOTAL MERCURY CONTENT (IN PPM)
0-0.10
Bloater
Crayfish
Chub
Hatchery trout
L. whitefish
Salmon
Shiner
Crab
Clam
King crab
Lobster tail
Oyster
Scallops
Shrimp
Other shellfish
Alewife
Anchovies
Butterfish
Cod
Fish sticks
Haddock
Herring
J. mackerel
Ling
Ocean perch
Salmon
Sardines
Seafood plate
Smelt
TV dinners
Whitefish
Whiting
Flounder
0.11-0.25
Bluegill
Buffalo
Bullhead
Carp
Catfish
Crappie
Coho salmon
Goldeye
Goldfish
Gar
Pumpkinseed
River carp
Rockbars
Shad
S. mullett
Sturgeon
Sunfish
Trout
D. crab
Lobster
Dolphin
Halibut
Pollock
Rockf ish
Scup porgy
0.26-0.45 0.46-0.65 0.66-0.99 1.00-1.70 5.5
Drum Eel Muskellunge Crevelle jack Blue marlin
N. pike Bluefish N. squawfish Grouper
Perch Dogfish shark Pickerel Ocean catfish
Sanger Gag Walleye Swordfish
Sheephead Lingcod Redfish
Sucker Mullett S . mackerel
Whitebass Sea catfish
Bonita Sea trout
Croaker White marlin
K. mackerel
Menhaden
Pompano
Red snapper
Sablefish
Tuna
Bass
Source: Peyton et al., 1975.
-------
TABLE 4.2. MERCURY RESIDUES IN CANNED SEA FOOD
Methylmercury ,
Sample Product ppmd
1
2
3
4
5
6
7a
8a
9
10
11
12
13
14
15
16b
17
18
19
20
21
22
23C
24C
25
26
27
28
29
30
31
32
33
34
35
36
Shrimp
Oysters
Oysters
Minced clams
Clam sauce
Cat food
Sardines
Anchovies
Kippered herring
Pink salmon
Red sockeye salmon
Coho red salmon
White tuna
Tuna
Light tuna
0.007
0.020
0.027
0.029
0.088
0.012
0.019
0.0.15
0.021
0.090
0.081
0.009
0.023
0.015
0.045
0.025
0.31
0.20
0.25
0.32
0.22
0.34
0.28
0.35
0.68
0.50
0.31
0.25
0.53
0.33
0.23
0.40
0.15
0.29
0.18
0.29
Total Mercury,
0.009
0.037
0.033
0.046
0.047
0.033
0.035
0.039
0.038
0.21
0.13
0.016
0.064
0.020
0.047
0.018
0.38
0.24
0.39
0.38
0.20
0.43
0.36
0.39
0.73
0.57
0.45
0.21
0.60
0.43
0.24
0.55
0.13
0.26
0.20
0.33
Methylmercury ,
78
54
82
63
187
36
54
38
55
43
62
56
36
75
96
139
82
83
64
84
110
79
78
90
93
88
69
119
88
77
96
73
115
112
90
88
Source: Hall, 1974.
Samples 7 and 8 had the same lot number.
Average percent methylmercury in tuna Samples 17-36 = 89 percent.
.Samples 23 and 24 had the same lot number. Both cans were unlabeled.
Determined by gas-liquid chromatography.
Determined by atomic absorption spectrometry.
4-4
-------
TABLE 4.3. MERCURY CONTENT OF SELECTED FOOD FISH
J>
I
Concentration, ppm
Location
Region 1
Pacific and Alaska
Region 2 Southwest
Date
1969
1970
1969
Region 3 North Central 1969
Region 4 Southeast
Region 5 Northeast
Alabama
Florida
Georgia
Kentucky
Murray area
Montana
Ninemile Creek
Clark Fork River
Flint Creek
Rattlesnake Creek
Ohio, Sandusky
Michigan , Saugatuck
Wisconsin, Bay field
1969
1969
1970
1970
1970
NA
NA
NA
NA
NA
NA
NA
NA
1968-
1969
Organism
Fish
Fish
Fish
Fish
Fish
Fish
Fish
Crabmeat
Fish
Unspecified,
cooked
Trout
Whitefish
Shiner
Sucker
Squawf ish
Brown trout
Sculp in
Unspecified
Sample Site
Composite
Composite
Composite
Composite
Composite
Composite
Composite
Composite
Muscle
Muscle
Muscle
Muscle
Muscle
Muscle
Muscle
Muscle
Whole fish
and fish
livers
Mean
0.25
0.26
0.08
0.20
0.23
0.23
0.36
0.39
0.40
0.375
0.15
0.17
0.13
0.27
0.25
0.53
0.27
N.A.
Range Reference
0.06-1.25 Henderson and Shanks, 1973
0.05-1.7
<0. 05-0. 14
<0. 05-0. 50
<0. 05-1.0
<0. 05-0. 80
0.01-2.26 Granade, 1972
0.33-0.50
0.0-1.70
Dassani et al., 1975
NA Van Meter, 1974
NA
NA
NA
NA
ND
NA
<0.010 Lucas et al., 1970
NA = Not available.
-------
(2) Concern exists over the possibility that the widespread
usage of organomercurial preparations in agriculture
in past decades may have increased the mercury content
of crops.
(3) Data on nonfish commodities are essential in determining
the relative contribution of the various food groups to
total dietary intake of mercury.
The most important determinants of mercury concentration in food are
the environmental level of mercury in the area where a food is produced
and the use of mercury-containing compounds in agricultural and industrial
production of the food. Organomercurials have been widely used as seed
preservatives and antifungicidal agents sprayed on the foliage of many
commercially grown fruits and vegetables, especially fruit trees, potatoes,
and tomato plants (Dassani et al., 1975; Hugunin and Bradley, 1975). Foliar
application of phenylmercurials produces residue levels in crops four to
six times greater than those in untreated controls (D'ltri, 1972).
Recently, usage of mercury in seed dressings and fungicides has been
severely curtailed. The use of mercurial pesticides as seed treatments
was banned in February, 1976, and later reinstated in August, 1976.
Production of these compounds must cease by August 31, 1978, or earlier
if the maximum allowed inventory (an estimated 50,000 pounds) is reached.
Any pesticides produced before the August deadline will become "existing
stocks" which can be sold, distributed, and used until those stocks are
depleted (Train, 1976; U.S. Environmental Protection Agency, 1976b). Data
presented by Dassani et al. (1975) and Gerdes et al. (1974) suggest that
the application of mercury fungicides in the treatment of wheat, tomato
plants, and fruit trees is still in practice.
In a "market basket" survey of common fresh fruits and vegetables
available in American supermarkets, Gerdes et al. (1974) assessed the
impact of the use of mercury in agriculture. As shown in Table 4.4, 19 of
23 common vegetables had mercury concentrations below 0.05 ppm. Okra,
cabbage, hot pepper, and string beans had mean mercury concentrations
greater than 0.05 ppm. Higher levels were found in those fruits which had
been sprayed with mercurial fungicides. The observed differences between
commercially obtained peaches (0.063 ppm) and home-grown ones (0.019 ppm)
(Table 4.4) may reflect either application of a mercurial fungicide on the
commercial peaches or differences in the amount of mercury in the environ-
ment in the areas where the peaches were grown.
As shown in Table 4.5, levels in most foods other than fish were
below the recommended maximum of 0.05 ppm (Joint FAO/WHO Expert Committee
on Food Additives, 1972). Staple foods grown in or available in Michigan
were examined by Gomez and Markakis (1974) for total mercury levels.
Dairy and poultry products, red meats, cereals, fruits, vegetables, and
miscellaneous items, along with many varieties of fish and shellfish,
were analyzed (Table 4.5). Mercury concentrations in land-produced
foods (not suspected of man-induced contamination) were in the range 0.01
to 0.03 ppm. Fish samples, by comparison, contained larger quantities of
4-6
-------
TABLE 4.4. MERCURY CONTENT OF FRESH FRUITS AND VEGETABLES
COMMERCIALLY AVAILABLE IN DENTON, TEXAS
Food Product
Fruits
Apple, red
Apple, yellow
Banana
Cherry
Grape , red
Grape, green
Grapefruit
Lemon
Lime
Melon
Nectarine
Orange
Peach
Peach, homegrown
Pear
Plum
Strawberry
Vegetables
Bell pepper
Black-eyed peas
Broccoli
Cabbage
Carrott
Cauliflower
Celery
Corn
Cucumber
Egg plant
Green onion
Hot pepper
Lettuce
Lima beans
Lima beans, dried
Mushrooms
Okra
Onion, white
Pinto beans, dried
Potato
Radish
Squash
String beans
Sweet potato
Tomato
Corn meal
Flour, white, bleached
Rice
Sugar
No. of
Samples
2
1
4
2
1
1
1
2
2
1
2
1
4
8
2
7
5
2
2
1
2
3
2
2
2
2
1
3
4
1
2
1
4
8
2
1
4
4
3
7
1
4
1
2
1
1
Concentration, ppb
Mean
14
86
85
8
113
88
31
110
111
8
97
92
63
19
45
124
48
37
5
26
59
5
24
16
16
10
47
15
55
20
46
19
43
73
44
17
34
4
3
51
21
31
98
103
87
51
Range
7-25
83-92
32-147
4-14
105-120
83-92
28-34
75-158
87-135
6-13
94-100
74-102
57-73
16-20
0-92
47-282
43-53
1-103
2-10
24-27
27-123
4-6
20-46
7-23
6-33
2-19
45-48
12-18
50-60
19-21
40-50
17-21
32-53
57-97
33-49
11-22
26-42
1-7
1-5
46-57
19-24
20-36
93-103
92-118
80-92
49-52
Source: Gerdes et al., 1974.
4-7
-------
TABLE 4.5. MERCURY CONTENT OF FOODS (EXCLUDING FISH)
Location'
Food Product
No. of Concentration, ppm
Samples Mean Range
Reference
Kentucky,
western
00
Michigan
Flour 28
Grains, composite
Oats
Rice
Wheat
Meats
Bacon
Chicken, gizzard
Chicken, liver
Ham, cooked
Hamburger
Pork, sausage
Weiner
Vegetables and fruits
Beans, green
Beets, seed
Carrot
Carrot seed
Onion
Onion
Potato
Tomato, fruit
Tomato, seed
Fresh fruits composite
Bread, white 2
Bread, white
Dairy
Cheese, Cheddar 2
Cheese
Milk, whole unpasteurized 2
0.003b 0.003-0.06
0.002-0.048
0.012
0.05-1.0
7.15
0.072
0.007
0.0009
0.010
0.011
0.047
0.008
0.017
0.042
0.030
0.007
0.012
0.05
9.45
0.00-0.28
0.00-1.09
0.004-0.035
0.01 0.005-0.01
0.01
0.02 0.015-0.03
0.08
0.01 0.01-0.02
Tanner et al., 1972
Goldwater, 1971
Dassani et al., 1975
D'ltri, 1972
Dassani et al., 1975
Hammons et al., 1975
Dassani et al., 1975
Hammons et al., 1975
Dassani et al., 1975
Goldwater, 1971
Gomez & Markakis, 1974
Hammons et al., 1975
Gomez & Markakis, 1974
Goldwater, 1971
Gomez & Markakis, 1974
-------
TABLE 4.5 (Continued)
Q
Location
Michigan
Food Product
Dairy
Milk, whole pasteurized
Milk, spray dried
Eggs, whole
Eggs
Grains
Oats, garry grain
Rice, polished grain
Wheat, dickson grain
Meats
Beef, unspecified
Beef, liver
Beef, muscle
Chicken
Chicken, liver
Chicken, muscle
Pork, liver
Pork, muscle
Salt, noniodized
Sugar
Sugar, white
Vegetables and fruits
Beans, red kidney, dry
Potatoes, russet, flesh
No. of
Samples
2
2
3
33
1
2
2
23
2
2
24
2
2
3
3
2
22
3
2
2
Potatoes, russet, unwashed 2
North Dakota
peel
Potatoes, russet, washed
Tomato , fruit
Dairy
Milk, whole
Egg, melange
peel 2
2
155
405
Concentration, ppm
Mean
0.01
0.02
0.03
<0.002b
0.01
0.01
0.02
0.003
0.01
0.01
0.003
0.03
0.02
0.03
0.005
0.06
<0.003
0.01
0.03
0.01
0.03
0.01
0.0008
0.012
Range
0.005-0.01
0.01-0.03
0.02-0.04
<0. 002-0. 005
0.005-0.01
0.005-0.01
0.01-0.025
0.002-0.007
0.01-0.015
0.00-0.02
0.001-0.007
0.015-0.03
0.015-0.03
0.02-0.04
0.00-0.005
0.03-0.09
<0. 003-0. 010
0.005-0.01
0.02-0.035
0.01-0.015
0.02-0.03
0.01-0.02
0.00-0.01
ND-004
ND-0.442
Reference
Tanner et al. , 1972
Gomzz & Markakis, 1974
Tanner et al., 1972
Gomez & Markakis, 1974
Tanner et al. , 1972
Gomez & Markakis, 1974
Tanner et al., 1972
Gomez & Markakis, 1974
Sell et al., 1975
-------
TABLE 4.5 (Continued)
a
Location
North Dakota
United States,
Location
unspecified
No. of
Food Product Samples
Egg yolk
Meats
Pork, liver 156
Beef, muscle 453
Milk, whole
Milk, whole 32
Milk, dry 33
Vegetable composite
Vegetables, fresh composite
Vegetables, canned composite
Potatoes
Concentration, ppm
Mean
0.062
0.015
0.005
NDC
<0.001b
0.010b
0.003b
Range
0.001-0.15
ND-0.304
ND-0.046
<0. 001-0. 009
0.004-0.027
0.00-0.06
0.002-0.010
0.005-0.025
0.006-0.020
0.001-0.015
Reference
Goldwater, 1971
Sell et al., 1975
Murthy, 1974
Tanner et al. , 1972
Goldwater, 1971
D'ltri, 1972
Goldwater, 1971
D'ltri, 1972.
Tanner et al. , 1972
Indicates food grown in or available in the state mentioned.
Median rather than mean given.
"Not detected or below detection limits.
-------
mercury; however, all samples were below the FDA action level for fish
(0.5 ppm).
Concentrations of mercury in animal products and soils of North
Dakota were reported by Sell et al. (1975). Average levels in both muscle
and liver of beef and swine were considerably below 0.05 ppm (Table 4.5).
In fact, only 8 out of 399 beef samples (2 percent) had mercury levels in
excess of 0.020 in muscles; only 3 samples of beef liver contained greater
than 0.05 ppm. Marked variations were seen among individual eggs produced
at the same time and on the same farm, suggesting the possibility that
extraneous (nonfeed) mercury was being consumed by free-ranging hens.
Similar observations of wide variation in individual beef and swine also
suggest that some individuals may have incidental mercury exposures (Sell
et al., 1975).
No apparent trends of increasing or decreasing exposure emerge when
data from recent studies are compared with those obtained by Stock and
Cucuel in 1934 and Gibbs in 1941 (Sell et al., 1975). Mercury levels in
key foods of animal origin have apparently remained about the same over
the past 30 to 40 years, according to Sell et al. (1975). The analytical
techniques used in the earlier studies were undoubtedly less accurate than
today's methods and such comparisons should not be accepted uncritically.
MERCURY IN THE MARKET BASKET
AND TOTAL DIET
The results of FDA's Total Diet Study, better known as the Market
Basket Survey, represents the most comprehensive measurements on the in-situ
levels of mercury in foodstuffs (Peyton et al., 1975). Not only do the
FDA's Total Diet Studies gather a representative cross-section from 30
markets in 27 different cities but also great care was taken in these
studies to prevent sample contamination and to assure a sensitive and
accurate analysis (Peyton et al., 1975).
A study by Tanner and Forbes (1975) involved more extensive sampling
of food, utilizing the FDA Total Diet Study protocol. This "market basket"
approach is common to all of the studies discussed in this section and can
be described as follows:
(1) One hundred seventeen food items selected to represent
the 2-week diet of an American male 15-20 years old are
collected in various geographical locations at regular
intervals throughout the year.
(2) Six composites of each of 12 food categories are
obtained from 5 regions of the United States.
(3) Foods are weighed, prepared as they are normally eaten,
and composited. The composites are slurried and then
analyzed.
4-11
-------
All commodity groups, except meat, fish, and poultry, contained less than
0.01 ppm mercury (Tanner and Forbes, 1975). Mercury levels as high as
0.041 ppm were found in the meat, fish, and poultry group; but when the
composite was analyzed component by component, only the fish component
had mercury levels greater than 0.1 ppm. The mercury concentrations for
the 11 remaining food groups of the Total Diet Study were well below the
0.05 guideline figure for foods other than fish; mercury levels detected
in these foods were generally less than 0.01 ppm. Only the meat, fish,
and poultry food group regularly contained measureable amounts of mercury.
Mercury ranked 20th in a list of 33 different residues detected by
the FDA's Total Diet Survey during FY 1971 in terms of number of positive
occurrences (Manske and Corneliussen, 1974). Mercury residues were found
in 10 of 240 composites. All 10 positive composites occurred in meats,
fish, and poultry. Among the 10 positive composites, mercury was detected
in 7 composites but at levels below quantification, reported as "trace".
The range of the positive composites was from "trace" to 0.05 ppm mercury.
Separate analyses of the components of this category revealed seafoods as
the principal source of mercury.
In FDA's Total Diet Survey from FY 1973, virtually all dietary intake
of mercury was found in the meats, fish, and poultry composite (Mahaffey
et al., 1975). Mercury was identified in 97 percent of the composites,
averaging 0.011 ppm in the composite of meat, fish, and poultry (Table
4.6). Trace amounts were detected in a small percentage of the grains
and cereals, root vegetables, and oils, fats and shortening composites.
Data from Manske and Corneliussen (1974), Mahaffey et al. (1975), and
Carroll et al. (1975) (reporting National Pesticide Monitoring Program
data) are presented in Table 4.6. Peyton et al. (1975) assembled FDA data
which yield the high (26 ppb-Group II) and low (less than 1 ppb in many
food groups, 9 ppb in Group II) median values for any U.S. region (Table
4.7). Maximum reported mercury concentrations for each food group range
from 29,400 ppb in red meat to 40 ppb in dairy products.
ESTIMATED DOSAGE
Estimated daily intakes of mercury calculated on the basis of FDA
Total Diet Survey data for the years 1971-1974 (Mahaffey et al., 1975) are:
1971 - 2.48 yg/day (Goldwater, 1974)
1972 - 3.85 yg/day
1973 - 2.89 yg/day
1974 - 2.84 yg/day (estimated)
Mahaffey et al. (1975) believe that the estimates presented are
quite accurate for the years 1972-1974 and reflect no trends of increasing
or decreasing mercury exposure through diet for that period.
Table 4.8 shows the wide variation in dosage of mercury from standard
diets in different age-sex groups. Children less than 1 year of age receive
the greatest mercury dose on a per weight basis (Peyton et al., 1975).
4-12
-------
TABLE 4.6. MERCURY CONTENT IN FOODS: NATIONAL PESTICIDES
MONITORING PROGRAM MARKET BASKET DATA
Number of Mean Con-
Positive centration,
Location Date3 Food Class Composites'3 ppm Reference Remarks
United States 1973 Total diet study. Positive Mahaffey et al., 1975 Mercury concentrations
Sampling composites were found in reported as total
locations the following categories: mercury.
throughout Food class II
U.S. Meat, fish and poultry 0.011 Detected in 97% of samples.
composite
Food class III
Grains and cereals Oc Detected in 3% of samples.
composite
Food class VII
Root vegetables Oc Ditto.
composite
Food class X
Oil, fats and shorten- Oc
ing composite
Food class XII
Beverage composites Oc
National Totals 1971 Food class II
I Meat, fish and poultry 0.02 Manske and
|_i composite Corneluissen, 1974
U>
Regions
f.ali'fornia, 1971 Food class II
Los Angeles Meat, fish and poultrv 3 Carroll et al., 1975 National Pesticides Monitor-
composite ing Program initiated mercury
analvsis in October 1970.
Maryland, 1971 Food class II 1
Baltimore Meat, fish and poultry
compos i to
Massachusetts, 1971 Food class II .1
Boston Meat, fish and poultry
compos ite
Minnesota, 1971 Food class II 0 Carroll er al . . 197^
Minneapolis Meat, fish and poultry
compos ite
Missouri, 1971 rood i-l.iss II 1
Kansas Cltv Meat, fish and poultry
composite
aD,ites in this table are I'ise.il years.
^Number of positive eomponites out of i possible 10.
I ra
-------
TABLE 4.7 SUMMARY VALUES FOR MERCURY LEVELS
IN NONFISH COMMODITIES
(ppb)
FDA
Type of Commodity
Low High Maximumsa
I Dairy product
II Meat, poultry, fish
(composite)
Red meat
Poultry
III Grain and cereal products
TV Potatoes
V + VI + VII (composite)
Vegetables
V Leafy vegetables
VI Legume vegetables
VII Root vegetables
VIII Fruits
IX Sugars, fats, oils
X Beverages
Beer
(<1) 1 3
9 26
(<2) 2 8
(<1) 1 7.5
1 2.5
(
-------
TABLE 4.8. ESTIMATED MERCURY DOSE THROUGH STANDARD DIETS (yg/day)
U.S. per capita
FDA
Type of Commodity Low High Other
I Dairy products 0.44 1.82 3.08
II Meat, poultry, fish 2.90 8.37 24.15
85% CH3Hg+ (2.46) (7.11) 20.52
III Grain and cereal 0.40 1.62 3.02
IV Potatoes 0.17 1.26 0.84
V+VI+VII Vegetables 0.20 0.49 3.37
V Leafy vegetables
I VI Legume vegetables
Ui
VII Root vegetables
VIII Fruits 0.16 0.48 2.74
IX Sugars, fats, oils 0.58 0.58 9.07
X Beverages - Other 0.50 0.50 0.50
Beverages - Beer
Total Hg dose per person,
Pg/day 5.35 14.62 46.77
pg/pg-day
Methylmerdury dose per
person, Mg/day 2.46 7.11 20.52
Mg/kg-day
Weight :
Male a
F
Low
0.89
1.93
(1.64)
0.87
0.18
0.05
0.07
0.16
0.29
0.41
1.20
6.05
0.089
1.64
0.024
67.9 kg
ge: 19
DA
High
2.66
5.56
(4.73)
3.50
1.37
0.23
0.14
0.32
0.87
0.41
1.20
16.26
0.239
4.73
0.070
Weight :
1 ye
FDA
Low
0.80
0.45
(0.38)
0.05
0.01
0.01
0.02
0.04
0.01
1.39
0.180
0.38
0.049
7-7 kg
:ar
High
2.40
1.30
(1.13)
0.20
0.04
0.03
0.05
0.04
0.01
3.89
0.503
1.13
0.146
Weight :
Male agi
Fa
Low
0.70
2.47
(2.10)
0.25
0.09
0.08
0.10
0.29
0.43
4.41
0.680
2.10
0.033
64.5 kg
2: 15-17
4
High
2.10
7.15
(6.08)
1.10
0.67
0.19
0.30
0.29
0.43
12.23
0.189
6.08
0.094
Weight
Female A;
F:
Low
0.48
1.80
(1.53)
0.17
0.05
0.08
0.08
0.19
0.39
3.24
0.058
1.53
0.027
55.
f>e:
DA
H
1
5
(4
0
0
0
0
0
0
8
0
4
0
5 kg
15-1
igh
.44
.20
.42)
.69
.38
.19
.24
.19
.39
.72
.157
.42
.079
Weight
7 Male £
Low
0.28
2.70
(2.30)
0.22
0.08
0.08
0.10
0.26
0.80
0.14
4.66
0.059
2.30
0.029
:: 79.1 kg
ige: 35-54
FDA
High
0.84
7.80
(6.63)
0.90
0.56
0.20
0.30
0.26
0.80
0.14
11.80
0.149
6.63
0.084
Source: Peyton et al., 1975.
-------
The U.S. per capita estimated mercury dose in standard diets reported
by Peyton et al. (1975) in Table 4.8 ranges from 5.35 to 14.62 yg/day.
Dietary mercury exposure for the upper 10, 5, 1, and 0.1 percent of the
population in terms of fish consumption is shown in Table 4.9 (Peyton et al.
1975). Persons belonging to Weight Watchers or others having special diets
which substitute fish for meats are expected to receive above average
quantities of mercury in their diets. Peyton et al. (1975) have tabulated
these dosage data in Table 4.10.
4-16
-------
TABLE 4.9. MERCURY EXPOSURE FROM THE DIET OF FISH EATERS
Fraction of
Population
Exceeding
Grams per day
of Purchased
Fish
Mercury Exposure
from Purchased Fisha
Mercury Exposure
from Total Diet
10%
5%
1%
0.1%
26
38
77
165
4.2 g/day
6.1
12.3
26.4
12.3 g/day
14.0
19.9
33.1
Source: Peyton et al., 1975.
o
Assumes that the types of fish consumed are the same as for the
average population in the Market Facts survey.
TABLE 4.10. MERCURY EXPOSURE FROM THE DIET OF WEIGHT WATCHERS
Source
Grams per day
Consumed
Mercury
Exposure, yg
Shrimp
Salmon
Scallops
Tuna
Other fish
Total fish
Other meats
Other food
Total mercury
16.3
16.3
16.3
16.3
32.6
97.8
114.0
1.0
0.7
0.5
5.8
5.2
13.1
1.1
4.6
18.8
Source: Peyton et al., 1975.
4-17
-------
5. MERCURY IN MAN
Nordberg (1976) has divided mercury compounds into three functional
categories on the basis of toxic properties: (1) mercury vapor, (2)
inorganic mercury salts and phenyl- and methoxyethylmercuric salts, and
(3) methyl- and ethylmercuric salts. This review follows this same
classification scheme.
MERCURY VAPOR
Persons employed in the manufacture of scientific instruments,
electrical meters, alkalies and chlorine, mercury vapor lamps, amalgams,
solders, and jewelry are potentially exposed to mercury vapor (Browning,
1969), and concentrations of mercury vapor occur in laboratories of
chemistry, physics, dentistry, and medicine (Casarett and Doull, 1975).
Mercury vapor is absorbed primarily through the lungs and respiratory
tract, although small amounts may also be absorbed percutaneously (Nordberg,
1976). Gastrointestinal absorption after oral ingestion is minimal. In
contrast, absorption of an inhaled dose by the lung has been estimated as
75 percent complete (Clarkson, 1975). After absorption, elemental mercury
is transported by the blood where it may be either oxidized to the divalent
ion in the red blood cells and tissues or may remain dissolved in the
elemental form in the blood and transported in this form across the blood-
brain barrier and oxidized later in the brain tissue (Casarett and Doull,
1975). Most of the absorbed mercury is transported within the first few
days to the kidney and also to a lesser extent to the liver. After
repeated exposure, mercury steadily accumulates in the kidneys where it
is bound by sulfhydryl groups. At least 1 percent is absorbed by the
brain (Nordberg, 1976). Experiments in primates as well as human autopsy
findings have shown a differential pattern of distribution within the brain
(Glomski et al., 1973).
Primate studies suggest that the biological half-life of mercury in
the brain is probably on the order of years (Nordberg, 1976). The retention
in the kidney is considerably shorter than that in the brain; however,
retention rates in the kidney are not uniform. Instead, the kidney behaves
as a multicompartmental system; at least one compartment shows rather long
retention with biological half-life exceeding 1 month (Nordberg, 1976).
These differential retention rates within the several "compartments"
are poorly understood. Clarkson (1975) has estimated a whole-body elimina-
tion half-life of 58 days from a study of human volunteers who inhaled
radioactive mercury vapor.
5-1
-------
The primary means of excretion of mercury are feces and urine, but
smaller amounts may also be eliminated in sweat, milk, and hair. At low
doses, the majority of body burden is eliminated via bile and feces. As
dosage increases, however, a larger proportion is eliminated in the urine
(Nordberg, 1976).
No diagnostic index medium (i.e., blood, hair, urine, etc.) has been
found which parallels the concentration of mercury in the brain from
exposure to mercury vapor. Neither blood nor urine accurately reflects
brain levels after exposure to mercury vapor and there is no simple
correlation between these parameters (Nordberg, 1976). Likewise, there is
no suitable index media to reflect lung levels.
Approximately 210,000 pounds of mercury per year are used in
dentistry. Each practicing dentist uses, on the average, 2.5 pounds of
mercury annually in the preparation of dental amalgam restorations.
Because the exposure of the dentist and his assistants to this quantity
of mercury suggests the potential for toxicity, Stevens et al. (1972)
conducted measurements of mercury vapor at the Naval Dental Clinic (NDC)
at the Washington Navy Yard, the dental clinic at the Naval Graduate Dental
School (NGDS), and the staff dental clinic at the National Naval Medical
Center (NNMC). Atmospheric concentrations of mercury in air at each of
the facilities were measured throughout the day, at varying distances
from the floor corresponding to the breathing zone of the patient and
the operator. Additional measurements were made during vacuuming in the
pertinent carpeted areas, trituration of amalgam with the amalgamator,
and on a dental assistant's hands before and after washing. Urine
samples from assistants working in the room with the highest concentration
(the staff clinic) were compared with control samples from persons working
in the same facility but having no known exposure to mercury. Table 5.1
shows mercury vapor concentrations in dental operating rooms at the three
naval dental facilities. Readings at different heights did not differ
significantly. Values for all dental operating rooms tested ranged from
a low of 0.001 ppm (0.012 mg/m3) to a high of 0.024 ppm (0.200 mg/m3). The
highest readings were obtained in the staff clinic during vacuuming of a
carpet in a room where a mercury spill had occurred 4 months previously.
The concentration was recorded at 0.004 ppm (0.035 mg/m3) prior to vacuuming,
peaked to 0.024 ppm (0.1999 mg/m3) during vacuuming, and immediately decreased
to 0.0096 ppm (0.080 mg/m3) when the vacuuming stopped. The level remained
above the threshold limit value of 0.0060 ppm (0.05 mg/m3) for a total time
of 25 minutes. Stamping the foot on the contaminated carpet was followed by
a peak reading of four times the threshold limit value, and peaks of about
twice that amount were recorded when the amalgam was triturated and also
when a drawer containing the amalgamator, mercury bottle, and pellets was
opened. Following each of these actions, the concentration decreased below
the threshold limit value within 5 seconds. Urinary mercury levels paral-
leled concentrations in air; the highest mean urine mercury level of 0.0112
ppm was obtained for the three persons working in the room at the staff
clinic where the mercury vapor in air was also highest. The observed eleva-
tions in urinary mercury levels are indicative of absorption well in excess
of the normal population. A study by Gutenmann et al. (1973) revealed that
89 percent of hair samples obtained from a survey of 115 New York dentists
5-2
-------
TABLE 5.1. MERCURY VAPOR CONCENTRATION IN NAVAL
DENTAL OPERATING ROOMS3
Facility
Navy yard, NDC
Clinic, NGDS
Staff clinic, NNMC
Number of
Readings
28
30
34
0
Concentration, pjnn (mg/m )
Mean
0.0031 (0.026)
0.0047 (0.039)
0.0067 (0.056)
Range
0.002-0.0096 (0.017-0.080)
0.001-0.011 (0.012-0.090)
0.003-0.024 (0.022-0.200)
Source: Stevens et al., 1972.
a ^
Conversion formula used to convert mg/m to ppm for air measurements:
3 _ ppm (molecular weight mercury, 200.59)
~ 24.04
were above the 0.01 to 2.5 ppm range observed in persons not exposed to
other than "normal" sources of mercury (Gutenmann et al., 1973). However,
correlation between number of years in practice and hair levels was not
significant.
Smith et al. (1973) studied the effects of mercury in 642 workers
exposed to varying levels of mercury vapor in the manufacture of chlorine.
Time-weighted exposure averages for mercury in air were determined at
numerous sampling points and the amount of time spent by each employee in
the different locations was specified, permitting accurate assessment of
individual exposures. The most important finding was the existence of a
close correlation (P<0.01) between time-weighted averages of mercury in
air, blood, and urine. Data from the study are presented in Figures 5.1
and 5.2. Such findings suggest that under chronic exposure conditions,
urinary excretion quite accurately reflects exposure to mercury, at least
on a group basis. A literal interpretation of the regression lines
indicates that an air concentration of 0.012 ppm (0.1 mg/m ) corresponds
to a blood level of 0.060 ppm and 0.260 ppm in urine.
MERCURIC MERCURY
Exposure to potentially toxic amounts of mercuric salts occurs almost
exclusively in industrial settings. In the past, however, ignorance of
the toxic effects of mercuric salts exposed a much wider proportion of the
population, not only through occupational exposures (especially in the
production of felt) but also through medicinal preparations, cosmetics,
and poisons. Recently, the most common uses of mercuric salts have been
in the paper and pulp industry, in the production of antifouling paints,
and to a lesser extent in the preparation of drugs, disinfectants, and
agricultural products. Mercuric salts are absorbed by the body primarily
through inhalation and dusts and ingestion, but significant percutaneous
5-3
-------
E
O
o
x
o
20i-
15
Ot
X.
o
o
ffi
Oo°
0.05 0.10 0.15 0.20 0.25 0.30 O.35
Hg AIR LEVELS (mg/m3) Time-weighted averages
Figure 5.1. Mean blood levels of mercury versus time-
weighted averages of mercury in air
(Smith, 1972)*
0.05 0.10 0.15 0.20 0.25 0.30
Hg AIR LEVELS (mg/m3) Time-weighted averages
Figure 5.2. Urine levels of mercury versus time-
weighted averages of mercury in air
(Smith, 1972)*
*Reprinted from ENVIRONMENTAL MERCURY CONTAMINATION, Hartung and Dinman,
Ann Arbor Science Publishers, Inc., 1972.
5-4
-------
absorption has also been documented (Casarett and Doull, 1975). Generally,
where exposure to inorganic dust occurs, it is in combination with mercury
vapor (Environmental Health Resource Center, 1973). Inorganic forms of
mercury taken orally are not absorbed very quickly by the body. Only about
2 percent of orally administered inorganic compounds is absorbed (Clarkson,
1972). Once absorbed, approximately 50 percent of the mercury is trans-
ported by the blood plasma and is rapidly excreted by the urine (Friberg and
Vostal, 1972). Following injection of a mercuric salt in animals, only
about 25 percent of total blood mercury is bound to the erythrocytes.
Comparable values for mercury vapor were 67 to 68 percent, for arylmercury,
50 percent, and for methylmercury, 90 percent, bound to red blood cells.
(Environmental Health Resource Center, 1973). In the blood, the soluble
inorganic mercurial is first attached to 6-globulins and erythrocytes but
later shifts to albumin from which it is redistributed to the tissues with
a biological half-life of about 15 days and is, therefore, more amenable to
excretion from the body in urine. Consequently, less is stored in the
organism following exposure to inorganic salts, relative to the forms
mentioned above (Friberg and Vostal, 1972). The amount and rate of
absorption of aerosols of mercury salts in the respiratory tract have not
been well established, but is probably less than that of mercury vapor
(Environmental Health Resources Center, 1973). Following acute exposure
to mercuric salts, the highest tissue concentrations are found in the kidney
and the liver. Inconsistent results concerning the relative mercury concen-
trations of the other organs have been reported, with most studies showing
minimal or nonexistent levels in the brain (Nordberg, 1976). Within a few
hours after administration, the mercury is found in human and animal tissues
in the following approximate order of decreasing concentration: pancreas,
kidney, liver, spleen, blood, bone marrow, upper respiratory and buccal
mucosa intestinal wall (especially colon), skin, salivary glands, heart,
skeletal muscle, brain, and lung (Goodman and Gilman, 1975). There is also
some indication that mercuric salts can be stored in bones (Goodman and
Gilman, 1975). Blood levels are high immediately after exposure, but they
diminish rapidly with time (Environmental Health Resource Center, 1973).
Inorganic mercury is slowly released from tissues, especially the intestines
and muscles (Friberg and Vostal, 1972). The favored excretion route follow-
ing absorption of mercuric salts is the urine, followed by the feces
(Browning, 1969). Smaller amounts are also excreted in the hair, milk,
saliva, and sweat (Nordberg, 1976).
Nordberg (1976) has reported studies on the biological half-life of
inorganic mercury compounds in human volunteers given an oral tracer dose.
That estimated for mercury in blood was 20 days, while that of the whole
body was estimated at about twice as long. Other studies reported by
Nordberg (1976) have estimated a whole-body biological half-life ranging
from 20 to 60 days for human adults. About 7 percent of the total admini-
stered dose was excreted during this time. Animal experiments suggest that
half-lives in kidney and brain are considerably longer than those of the
whole body. Animal experiments also indicate the possibility that blood
and urine levels may be an appropriate index of kidney concentration
(Nordberg, 1976). Regardless of the mode of exposure, the kidney is the
critical organ.
5-5
-------
The organomercurials, methoxyethyl- and phenylmercury, are discussed
in this section because their behavior in biological systems resembles that
of the inorganic mercury salts. Both types of compounds appear to be rapid-
ly metabolized to inorganic mercury, which is then eliminated (Friberg and
Vostal, 1972).
Phenylmercuric acetate (PMA) is used as an eradicating fungicide and
selective herbicide, especially on golf courses (Berg, 1976). Methoxy-
ethylmercurials are also used as fungicides; currently, they are replacing
methylmercury in many agricultural fungicide preparations (Nordberg, 1976).
The absorption and distribution patterns of phenyl- and methoxy-
ethylmercurials are remarkably similar to those of inorganic mercurials
(Casarett and Doull, 1975). After exposure, both organic compounds are
deposited in the liver and other tissues where they are converted into
inorganic mercury (Friberg and Vostal, 1972). Phenylmercurials are
hydroxylated on the ring, conjugated, and then decomposed to inorganic
mercury and phenol conjugates (Goodman and Gilman, 1975). The methoxy-
ethylmercurial shows a greater affinity for red blood cells than inorganic,
yet much less than methylmercury.
ALKYLMERCURIALS
The short-chain ethyl- and methylalkylmercurials have been used to
prevent seedborne diseases in cereal grains, and mercury fulminate is used
in the production of explosives (Browning, 1969). Methylmercury compounds
are much more readily absorbed by the gastrointestinal tract than inorganic
forms. Both human and animal experiments have shown 90 to 100 percent
gastrointestinal absorption of methylmercury, while comparable absorption
of inorganic salts is only about 50 percent (Zepp et al., 1974). Studies
on human volunteers given a single tracer dose of methylmercury revealed
the following metabolic characteristics (Clarkson, 1975):
(1) Absorption efficiency equals 95 percent of oral intake.
(2) One percent of daily intake was recovered from 1 liter
of whole blood.
(3) Whole body elimination half-life ranged from 52 to 93 days.
(4) Half-life clearance in blood was 45 to 105 days.
(5) A hair-to-blood concentration ratio of 250:1 was reported.
Methylmercury is well absorbed through the skin and lungs (Casarett and
Doull, 1975). The absorption of inorganic or organic mercury vapor through
the lungs poses a special problem because vapor exposure produces accumula-
tion of mercury in the brain far in excess of that found after an equivalent
dose of inorganic mercury is administered either orally or intravenously
(D'ltri, 1972).
5-6
-------
Studies of tracer doses of methylmercury showed that the liver and
head together accumulated 60 percent of the total body burden. The liver
accounts for 50 percent and the head, 10 percent, of the radioactive dose.
Probably the brain accounts for 90 percent of the head burden (Nordberg,
1976). Distribution also differs in that the levels of mercury in the
kidney, brain, and blood are generally within a two- or threefold range
of each other after exposure to short-chain alkylmercurials; differences
observed with other types of mercury may be in the 100-fold range (Casarett
and Doull, 1975). Methylmercury is preferentially accumulated in the red
blood cells; more than 90 percent of methylmercury present in blood is
bound to red cells (Clarkson, 1972). The superior biological stability of
alkylmercurials is shown by their resistance to degradation to inorganic
mercury which can then be eliminated from the body. The 70-day biological
half-life demonstrates slower excretion of methylmercury than all of the
other forms (Friberg and Vostal, 1972). Excretion of mercury after oral
administration of methylmercury is chiefly in the feces, although smaller
amounts are also excreted in the urine, hair, and milk (Environmental Health
Resource Center, 1973). In man, urinary excretion is slow at first but
accelerates during the first 30 days after exposure (Aberg et al., 1969).
Subcutaneous and intravenous injections produce more rapid excretion
in both urine and feces; however, the favored route for inorganic mercury
is urine, while that for organic is the feces (Browning, 1969). Few
comparable data on the metabolism of ethylmercury are available; however,
it seems quite similar to methylmercury in this respect (Nordberg, 1976).
A mean biological half-life for whole-body clearance ranging from
52 to 93 days with a mean value of 76 days was obtained from tracer studies
of volunteers given oral doses of 203Hg (Miettinen, 1973). Miettinen et al.
(1971) estimated a mean biological half-life in red blood cells of 50 days,
with a standard deviation of 7 days. In a study of persons exposed to
methylmercury through fish consumption during and after varying degrees of
exposure, Birke et al. (1972) observed a half-life of methylmercury of 99 to
120 days in blood cells, 47 to 130 days in plasma, and 33 to 120 days in
hair after correction for background levels in mercury. Figure 5.3 shows
decay curves in six subjects after the dietary change to low fish intake
or to mainly ocean fish, or both. A methylmercury biological half-life of
72 days (range 35 to 189 days) was found for the hair of persons who had
ingested methylmercury-treated grains (Al-Shahristani and Shihab, 1974).
MERCURY LEVELS IN HUMAN TISSUES
Mercury levels in tissues of both normal and exposed humans show
considerable variation, but the highest levels are found most frequently
in the kidney and liver (Environmental Health Resource Center, 1973).
Mercury levels from autopsy tissues (lung, liver, and kidney) from two
geographical areas showed 95 percent of the population having less than
3.0 ppm in kidney and 0.2 ppm in liver and 99 percent having less than
1.0 ppm mercury in the lung (Stein et al., 1974).
5-7
-------
Mercury in
Hair.
Blood Cells, and
Blood Plasma
(ng gm)
200.000
100.000 -
50.000 -
10.000 -
5.000 -
1.000 -
50 -
10 -
5 -
2-I
9
ob..
•o
Subject Tissue (Symbol)
5
1
i
8
3
9
Hair
Han
Hair
Hair
Hair
Hair
(*>
(0)
(.1)
(0)
(A)
(•)
180
,250
65
130
240
88
1 RBC (n) 270
o
8 RBC (O) 130
1 Plasma (n) 160
•O 8 Plasma (O) 160
0 200 400 600 800 1,000 1,200 1,400
Days After Dietary Change
Figure 5.3. Elimination of total mercury from hair,
blood cells, and plasma in six subjects
(Birke et al., 1972).
-------
Table 5.2 summarizes data obtained in the United States between 1970
and 1974. Over 70 percent of assays, regardless of organ or age, had a
mercury burden of less than 0.25 ppm wet weight (Mottet and Body, 1974).
They reported: (1) no statistically significant increase in mercury burden
occurred with age, indicating that past environmental exposures did not
exceed the capacity of the body to eliminate mercury; (2) elimination at
present levels of exposure equalled intake; and (3) a strong suggestion
that the urban population had a somewhat greater mercury burden than the
rural. The authors concluded that the general population had a mercury
burden below 1 to 2 ppm in kidney, 0.25 to 0.75 ppm in liver, and less in
other tissues.
Mercury was detected in 76 percent of all autopsy tissues examined
by Gabica et al. (1975). The specimens were obtained from residents of
three geographic regions of Idaho. About 3.5 times more mercury occurred
in kidney tissue than in liver; kidney levels were about ten times that
in the brain. The highest levels were found in samples from persons from
southwest Idaho where natural mercury deposits are found. Glomski et al.
(1973) found a pattern of selective accumulation within the brain in a
study of persons without known pathological exposure to mercury. As shown
in Table 5.2, the highest levels were generally found in the cerebellar
cortex, while the white matter of the cerebral hemispheres consistently
had the lowest or next lowest values in all individuals.
The upper limit of "normal" mercury levels in urine is 0.20 to 0,25
ppm. Seventy-five percent of the normal population have less than 0.005
ppm in blood and 95 percent have less than 0.04 ppm (Environmental Health
Resource Center, 1973). Mercury levels in blood, urine, and hair vary
according to exposure.
Table 5.3 presents data from several studies of hair mercury levels
in normal persons and others with known exposure. Benson and Gabica (1972)
detected mercury in all 1,000 samples of hair from Idaho residents. Their
study revealed no correlation between fish consumption and other common
sources of exposure to the measured levels. The mean concentration was
4.18 ppm and mean levels for males and females were 2.45 and 5.90 ppm,
respectively. The authors suggest sexual differences in hair may reflect
hormonal or biochemical influences.
Nord et al. (1973) sampled hair from residents of industrialized
Pasadena, California, and the nonindustrialized Los Alamos, New Mexico,
area. As shown in Table 5.3, hair from women from the Pasadena area
showed a mean concentration of 29.6 ppm compared with 20.1 ppm in hair of
women from Los Alamos. The authors state that their findings are higher
than other values reported in the literature, but they offered no specific
explanation. Environmental exposure indices (as measured in dustfall and
house dust) were significantly associated with values for scalp-hair
mercury in both children and adults (Creason et al., 1975). Eads and
Lambdins' (1973) study; however, did not show significant differences in
mercury levels in hair from persons in a polluted area (Port Arthur, Texas)
and literature values.
5-9
-------
TABLE 5.2. MERCURY CONTKNT OF SELECTED HUMAN TISSUE (AT AUTOPSY)
Ul
I
Location Date
Idaho
Statewide 1973-
1974
b
New York
Buffalo and NA
adjacent Great
Lakes area
Washington (State) ° 1970-
1972
No. of
Samples
28
14
58
36
61
45
6
7
5
7
6
6
7
60
61
57
95
95
77
69
32
60
59
41
Concentration, ppm
Organ and Site
Brain
Kidney
Liver
Brain, frontal lobe cortex
Brain, cerebellar cortex
Brain, medulla
Brain, pons
Brain, midbrain
Brain, thalamus
Brain, white matter
Brain, cerebellum
Heart
Kidney
Liver
Lung
Muscle, unspecified
Pancreas
Skin
Spinal cord
Spleen
Age and Sex
Males, all ages
Females , all ages
Males, all ages
Females , all ages
Males, all ages
Females, all ages
Adults, both sexes
Ditto
11
n
11
11
it
Composite sexes
and ages
Ditto
ti
ii
IT
II
tl
II
II
II
Mean
0.06
0.10
1.06
1.06
0.15
0.53
0.377
0.659
0.354
0.419
0.288
0.323
0.0786
0.132
0.081
0.102
0.757
0.250
0.251
0.126
0.065
0.193
0.087
0.122
Range
0.0-0.25
0.0-0.94
0.0-15.70
0.0-12.50
0.0-2.11
0.0-5.80
0.3-1.69
0.08-1.85
0.04-1.29
0.05-1.66
0.06-1.20
0.04-1.47
0.02-0.15
0.006-0.965
0.008-0.470
0.012-0.704
0.006-6.40
0.008-1.43
0.0-2.763
0.0-0.954
0.007-0.511
0.004-1.275
0.010-0.083
0.012-1.205
Source: Gabrica et al., 1975.
'Source: Glomski et al., 1973.
'Source: Mottet and Body, 1974.
-------
TABLE 5.3. CONCENTRATION OF MERCURY IN HUMAN HAIR—PERSONS OF LIMITED AND KNOWN EXPOSURE
Ln
1
No. of
Location Date Samples
California
Pasadena 1969 99a
Idaho
Statewide 1971 1,000
New Mexico
Los Alamos 1969 147
80
New York
Central NA 115
Metropoli- 1971 280
tan New 203
York City
Texas
Port Arthur NA 19
19
Concentration, ppm
Age and Sex
Adult, females
Composite sexes and ages
Ages 1-10, male
Ages 1-10 , female
Ages 11-20, male
Ages 11-20, female
Ages 21-40, male
Ages 21-40, female
Ages 41-60, male
Ages 41-60, female
Ages ^61, male
Ages -61, female
All ages, male
All ages, female
Adult , females
Adult, males
Adult, males
Ages 0-15, both sexes
Ages -16, both sexes
Males
Females
Mean
29.6
4.18
2.04
3.21
3.28
6.99
2.01
4.92
2.37
7.64
2.55
6.72
2.45
5.90
20.8
20.1
NA
/H
0.672d
0.774d
5.4
5.5
Range Reference
5.0-410.- Nord et al., 1973
0.12-139.0 Benson and Gabica, 1972
0.26-8.0
0.56-12.0
0.13-107.0
0.25-104.0
0.33-17.6
0.24-43.8
0.20-100.0
0.26-139.0
0.12-24.6
0.64-120.0
0.12-107.0
0.24-139.0
5.0-680.0 Nord et al., 1973
NAc
1.0-34.0 Gutenmann et al., 1973
0.048-11.30 Creason et a , 1975
0.050-14.00
0.2-12.4 Eads and Lambdin, 1973
0.1-139.0
computation of mean, leaving 98 samples.
One hundred forty-seven samples were actually taken; however the sample containing 680 ppm was not
included, leaving 146 samples.
NA = not available.
^Geometric mean.
-------
The absorption, accumulation, and excretion of methylmercury in man
has been extensively studied in experimental settings as well as in
"natural" exposures such as the epidemics of methylmercury poisoning at
Minamata, Niigata, and Iraq. Clarkson (1975) has utilized a mathematical
model of methylmercury metabolism to investigate relationships between
exposure levels and various indicator media such as hair, urine, and blood.
Nordberg (1976) has summarized the relationships discovered thus far as
follows:
• A specific relationship exists between levels in
each organ and total body burden of methylmercury.
• Definite relationships exist among the levels of
methylmercury in various organs.
• Elimination is correlated with body burden, i.e.,
a specific fraction of body burden is eliminated
per unit of time.
• A linear relationship exists between daily dose
and mercury levels in blood and hair.
• Levels in blood and hair are related in linear
fashion, with the hair levels about 250 to 300
times whole blood levels. Thus, hair is of
greatest potential value as an index media for
exposure to methylmercury. Also, hair allows
recapitulation of past exposure.
• At levels below which symptoms of toxicity occur,
accurate estimation of brain levels may be made
on the basis of blood levels.
• Urine values are of little value in estimating
body burden because not only are there low levels
of methylmercury present in the urine but also
the relatively larger proportion of inorganic
mercury present in urine introduces analytical
difficulties.
5-12
-------
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TECHNICAL. F!OJORT DATA
(I'lcusr ri'nd Infirm•timn; i.vi the lei'erse before c
1. IU.POHT NO.
EPA 560/6-77-031
4.TITLL ANDSUI5TITLE
MULTIMEDIA LEVELS—MERCURY
G. PERFORMING ORGANIZATION CODE
7. AUIHOR(S)
Battelle Columbus Laboratories
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Battelle Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201
12. SPONSORING AGENCY NAMh AND ADDRESS
Environmental Protection Agency
Office of Toxic Substances
Washington, D.C. 20460
3. RECIPIENT'S ACCESSION NO.
!i. REPORT DATE
September 1977
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-01-1983
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report is a review of environmental levels of mercury based on published reports
and other information sources. Mercury levels are reported for the atmosphere,
surface and ground waters, drinking water, sediments, soil, terrestrial and aquatic
biota, and man. The behavior of mercury in the environment is also discussed.
Higher than ambient levels of mercury are found near mercury mines, geothermal steam
fields, power plants, incinerators, sewage treatment plants, some industrialized
areas, and indoors where mercury is used. The release of mercury from natural sources
to air and water is double the man-related losses to these media. The levels of
mercury in biota are variable, depending on food habits and environmental conditions.
The highest levels occur in animals at the top of the trophic structure. Mercury
levels in tissues of humans are elevated in chlor-alkali industry workers, in
dentists, in people from areas with natural mercury deposits, and in urban populations
as compared with the rural.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Mercury
Water
Sediment
Soil
Air
Biota
Human
Food
Behavior
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATl rickl/Gump
8. DISTRIBUTION STATt-MUNT
Distribution unlimited
EPA Form 2220-1 (Rev. 4-77) PREVIOUS KUITION is OHSOLCTL
19. Sf-.CUHITY CLASS (This Kcportj
Unclassified
21. NO. OF PAGES
133
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
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