I/.
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-82-100 Mar. 1983
v>ERA Project Summary
Factors Influencing Metal
Accumulation by Algae
J. Charles Jennett, J. E. Smith, and J. M. Hassett
Shallow beds of algae (algal mean-
ders) have proved to be highly effective
at removing heavy metals and organo-
metallics from lead-zinc mine and mill
wastes. A laboratory-scale research
program was initiated to determine
conditions under which algae were most
effective at concentrating significant
quantities of As, Cd, Cu, Hg, N't, Pb, or
An, for the purpose of potential applica-
tion of the meander technology to new
types of waste water-metal problems.
Studies were performed on 20 species
of algae to determine interactions of
experimental variables affecting metal
adsorption, species and strains of algae,
type, form, and concentrations of metal,
pH, culture age, micronutrient compo-
sition of culture medium, exposure to
metal, and light intensity and exposure
period. These numerous variables were
studied by means of a rapid analytical
technique, the Titertek™* supernatant
collection system, to determine the
adsorption of metal radionuclides.
Metal removal was observed to be
fast (three hours), young growing cul-
tures were seen to be most effective,
and concentration factors > 1 x 104
were observed. The pH had little effect
on accumulation of metals except lead.
Heavy metals could be stripped from
algal mats with 0.01 M EDTA or 0.1 N
HNO3. Ca and Mg were not effective
competitors for the binding sites of Hg,
Pb, and Cd. Neither Zn nor As was
bound significantly at any pH. Experi-
mental and literature data indicate that
algae remove certain metals econom-
ically from a variety of waters and that
•Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use by the U.S. Environmental Protection
Agency.
the meander system can be used to
recover these metals for processing.
This report is submitted in fulfillment
of Grant No. R804734 by Syracuse
University under the sponsorship of the
U. S. Environmental Protection Agency.
This report covers the period from
September 13, 1976 through January
1,1979 and work was completed as of
June 30, 1979.
This Project Summary was developed
by EPA's Industrial Environmental Re-
search Laboratory. Cincinnati. OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Effluents from secondary lead smelters
are a major source of heavy metals in the
aquatic environment. These effluents are
frequently low in pH and contain a wide
range of heavy metals. The largest single
heavy metal constituent is, of course,
lead. Relatively large amounts of zinc,
cadmium, arsenic, copper, and other toxic
cations may also be found, along with a
wide variety of anions often associated
with these metals (chloride, sulfate,
nitrate and chromate for example). Lead
smelter effluents also contain toxic trace
organics generated when batteries and
other materials are crushed, and the
heavy metals are removed from their
plastic encasements. The fact that heavy
metals are dangerous in the aquatic
environment has been well documented
in the literature.
To protect the environment, the dis-
charge of heavy metals must be mini-
mized. One approach is to apply the type
of algal-meander treatment system cur-
-------
rently in use for treating mine and mine-
mill wastes at one site in the new lead-
belt region in southeast Missouri—the
world's largest lead mining region. A
detailed laboratory study of the factors
influencing heavy metal accumulation by
algae is the subject of this investigation
and an attempt has been made to evaluate
the feasibility of using algal meanders to
remove a variety of heavy metals.
Description of the
Meander Process
In the Missouri algal-meander system,
mine and mill wastes were treated in a
standard tailings pond followed by a series
of shallow meanders in which the growth
of algae is encouraged. These algae grow,
utilize the waste millings reagents and
trap heavy metals, both particulate and
dissolved, on their surface. When the
algae mat breaks loose, it is then trapped
in a settling pond at the end of the
meander system. The pond is equipped
with baffled weirs which prevent algal
overflow into the receiving stream. Based
on total heavy metals removed, the
system is more than 99-percent effective.
Dissolved heavy metals are also removed
to levels well below U.S. Public Health
Service drinking water standards. Past
work has shown also that lead in its
highly soluble acetate form is removed
effectively by the algae.
To date, the algal-meander system has
been used to treat only one waste, a
combined lead-zinc mine and mill waste
in the new lead-belt mining region. Since
1971, this region has been the site of a
large interdisciplinary investigation, sup-
ported by the National Science Founda-
tion, of environmental pollution by lead
and other heavy metals. It was confirmed
in 1974 that below the AMAX-Homestake
Lead Tollers, Inc., mining mills, severe
stream degradation and heavy metal
buildup was occurring. The meandering
system was built to a full operating scale
and as a result the stream was returned
to essentially pre-mining conditions. The
history of this treatment system and the
quality of the water in receiving streams
has been well documented for lead and
zinc. This technology, however, has not
been applied to wastes containing other
toxic metals. This has been largely due to
the lack of information on the system's
range of application and the newness of
the technology. The ability of algae to
concentrate heavy metals from their
aqueous environment has been reported
by radioecologists examining debris from
nuclear tests, chemical geologists at-
tempting to explain low-grade deposits of
metal, and ecologists concerned with the
self-purification of streams below mining
operations. While these observations are
clearly valuable, a more detailed know-
ledge of the interaction between algae
and heavy metals could aid in understand-
ing these processes. A systematic study
of these interactions has been difficult
because a wide range of variables affects
metal accumulation by algae. These
variables include the length of the expo-
sure period, the type of metal, oxidation
states, pH, salinity, and presence of
organic pollutants. To understand the
factors influencing metal accumulation
by algae in the meander system, labora-
tory studies were initiated with pure
cultures of representative species from
other laboratories and from the algal
culture collection at the University of
Texas.
Conclusions
The ability of representative algae to
concentrate large quantities of specific
heavy metals was demonstrated by adapt-
ing the Titertek™ supernatant collection
system (Flow Laboratories, Rockville,
Maryland) for assaying radionuclides of
heavy metals. This technique permitted
the simultaneous study of several factors
affecting heavy metal accumulation and
provided a sufficient number of replicates
for statistical analysis. Algal-metal com-
binations used in batch studies are pre-
sented in Table 1.
The removal and concentration of heavy
metals from their aqueous environment
by algae was first studied in detail in the
1950s and 1960s as part of the problem
of the release of nuclear debris from
weapons testing, and from reactor cooling
water effluent. Scientists took advantage
of the released isotopes, as well as newly
developed analytical techniques, to study
pathways of various elements in the
environment. One early result of this
work was the observation that certain
isotopes were concentrated by biota to a
much greater extent than the concentra-
tion of that isotope in water. From these
observations came the concept of the
concentration factor (CF) such that
C
CF= —
C1
where C and C1 are the concentration of
the radionuclide in the aquatic organism
and in the aqueous medium respectively.
The concept is also applicable to stable
isotopes (Polikarpov, 1966).
Calculation of concentration factors for
heavy metals revealed significant differ-
ences between species of the same genus
and between strains of the same species
(i.e., Nostoc). Some species regularly had
concentration factors of 1 x 104. In
general, young cultures exhibited very
much higher concentration factors than
old cultures. Most of the metal removed
by algae can be removed by a rinse with
0.01 M ethylenediaminetetraacetic acid
(EDTA) or 0.1 N nitric acid (HN03). This
information suggests that surface adsorp-
tion sites are the principal repository for
the metallic ions or particles.
The ability of algae to remove metals is
generally in this order: mercury > lead >
cadmium. Neither zinc nor arsenic was
removed significantly at any pH during a
three-hour exposure. The presence of
chelating agents in the medium (such as
EDTA) inhibited the removal of the heavy
Table 1. Algal-Metal Combinations Used in Batch Studies
Cations
Age
Alga (days) As(lll) As(VJ Cd Cu(ll)
Hg(ll) Ni(ll) Pb
Zn
Chlamydomonas
Chlorella
Spirogyra
Ulothrix
Ulothrix
Gleotrichia
Gleotrichia
Gleotrichia
Nostoc 31
Nostoc 586
Nostoc 586
Oscillatoria
Oscillatoria
12 + + + + + + + +
12 + + + +
12 + + + + + +
72 + + + + + + +
20 + + + +
12 + + +
20 +
40 +
40 + +
72 + + + + + + +
20 +
72 + + + ++ + + +
20 +
-------
metals. Calcium and magnesium were
not effective competitors for the binding
sites of mercury, lead, and cadmium.
There was remarkably little effect of pH
on metal accumulation in the range of pH
5 to 8, when young cells were employed.
Lead was the principal exception because
it was removed more efficiently at pH 4 to
5 than at other pH values.
The removals of lead and mercury from
nutrient solution by algae are found to be
rapid phenomena, usually accomplished
in three hours or less at room tempera-
ture. If the cells were placed in buffer
after the initial adsorption of lead, a
limited, slow release of lead occurred for
a few hours, perhaps while some surface
polymer-lead complexes were released
from dead or dying cells. Mercury was
removed from solution in nearly identical
fashion by two strains of Nostoc and
showed little evidence of being released.
In the control wells without algae there
were reproducible losses of 203Hg that
occurred within the first 24 hours at pH 6.
This may be related to reports in the
literature claiming volatilization of mer-
cury by algae.
Chlamydomonas (a green flagellated
form) proved to be dramatically superior
to all other species in its ability to remove
lead. Concentration factors for the orga-
nism of 1.9 x 10* were noted. This
organism showed essentially the same
concentration factor for lead in the pH
range of 4 to 9. In other experiments,
Ulothrix and Chlorella had concentration
factors for cadmium greater than 10".
The empirical successes of the algal-
meander system for removing lead from
surface waters can be explained in part by
the concentration and sequestering of
lead and cadmium on the surface of algal
cells. Very little heavy metal was leached
from these cells at pH 5 to 9 in the
presence of divalent cations and other
inorganic constituents of algal growth
media.
Results
Algal Growth
Algal growth for 20 species provided a
representative selection of algae for the
experiments. Some species proved impos-
sible to culture and others exhibited
unusual rates of growth. Table 2 reveals
that no growth was obtained from any
form in soil-water media. The choice of
African violet potting soil was probably
unfortunate because this soil is high in
humus. Success with this medium de-
pends on the selection of a garden soil
with a medium humus content.
A few algal forms were characterized
by unusual growth rates. Mougeotia and
Zygnema grew only slowly and to a low
final biomass. Nostoc 31, Nostoc W and
Gleotrichia exhibited a long lag phase.
For each of these forms, inoculation was
followed by about 15 days of apparent
inactivity. After this period, growth to a
useful final biomass was rapid. For these
forms, then, no young culture data are
available.
Table 2. Sources and Cultivation of Algae
Batch Studies
The results of the batch studies are
presented in Figures 1 through 8. The
figures show the concentration of metals
in the sample as a function of the time the
samples were withdrawn from the cul-
ture. It should be noted that, for reasons
of clarity, not all data points are shown on
the figures.
Arsenic ///—The data show no obvious
trends in the removal of arsenic III. The
highest removal (about 35%) was accom-
Algae
Source*
Type
Growth on media^
B D SW
A. Baccillariophytes
(diatoms)
Navicula pelliculosa
B. Chlorophytes
(green algae)
Chlamydomonas sp.
Chlorella pyrenoidosa
Chlorotylhum sp.
Kirchnerella sp.
Mougeotia sp.
Scenedesmus obliquus
Spirogyra sp.
Ulothrix fimbrinata
Zygnema
C. Cyanophytes
(blue-green algae)
Gleotrichia sp.
Nostoc muscorum A
Nostoc F
Nostoc muscorum H
Nostoc L
Nostoc muscorum W
Nostoc 31
Oscillatoria sp.
Nostoc 586
Schizothrix calcicola
D. Mixed Cultures
Cazenovia Lake
Onondaga Lake
UTEX668
Dr. C. Kuehnert
Syracuse University
Dr. N. Lazaroff
SUNY Binghamton
UTEX 758
UTEX2016
Dr. N. Lazaroff
Dr. N. Lazaroff
UTEX 923
Dr. Lazaroff
Pennate diatom
Unicellular, 2 flagella
Unicellular
Filamentous
Colonial, enclosed in
gelatinous matrix
Filamentous,
planktonic
Colonial, 4-8 cells.
planktonic
Filamentous,
planktonic
Filamentous, benthic
Filamentous,
enclosed by
mucilaginous sheath
Colonial
^University of Texas Culture Collection and Identification.
fB = Bold's medium; D = diatom medium; SW= soil water medium.
+=success
- - failure
-------
30-
10-
m... Control
A...Nostoc586(T2c/ay,l
O...Chlamydomonas (12 day)
A...Oscillatoria (20 day)
• ...Nostoc 37 (40 day)
9 12 15
Time (hours)
18
21
24
Figure 1. Uptake of arsenic (III) by various algae.
30
^20H
.o
I
10-
«... Control
&...Nostoc 586 (12 day)
O...Chlamydomonas (12 day)
A...Oscillatoria (12 day)
• ...Nostoc 37 (40 day)
9 12 15
Time (hours)
18
21
24
Figure 2. Uptake of arsenic (V) by various algae.
plished by Chlamydomonas, which also
had the lowest biomass (0.12 mg/ml).
Arsenic V—There are no obvious trends
in the removal of arsenic V. Most experi-
mental values are too close to the control
value to be considered significantly dif-
ferent. The lowest experimental value (16
//g/ml, compared to a control value of 20
mg/ml) was attained by Nostoc 586,
which had among the highest biomass
(0.40 mg/ml).
Cadmium—Cadmium was likewise not
dramatically removed by the algae used
in this part of the study. The lowest
experimental values (about 10 //g/ml)
were achieved by l//of/j/vx, which had the
highest biomass (0.34 mg/ml). That the
acid rinse for both Ulothrix and Nostoc
586 (with the next lowest experimental
value) had high concentrations of cadmi-
um indicates a surface adsorption mech-
anism for cadmium removal.
Copper—The highest removal of copper
(about 30% compared to the controls) was
attained by Gleotrichia, which had a
biomass of about 0.14 mg/ml. This alga,
though usually a dark brown mass of
filaments, turned greenish on exposure
to copper.
Lead—Lead appeared to be removed by
all the forms studied in this experiment,
with removal (compared to the 18-hour
control) of from 15% for Spirogyra to
about 87% for Oscillatoria. The green
filamentous Ulothrix showed high values
of lead removal, and the morphologically
similar Spirogyra showed values little
different from the controls, even though
both algae had nearly identical biomasses.
The high values of lead in the acid rinses
suggest again a surface adsorption.
Mercury—The most dramatic removal
of mercury was accomplished by Nostoc
586, which had an experimental value of
6//g/ml as compared to the control value
of 34 /ug/ml after only three hours. Again
the values of mercury in the acid rinses
were high.
Nickel—Although all algae seemed to
exhibit some removal of nickel (17% to
37% after 24 hours), no trends could be
discovered from the data.
Zinc—The algae that seemed to accu-
mulate zinc were Spirogyra (with 41%
removal after 18 hours) and Nostoc 586
(with 37% removal during the same length
of time). Again, the acid rinses of these
two algae had high values of zinc, sug-
gesting surface adsorption sites.
Discussion of Project Results
With the exception of zinc, these results
show reasonably good agreement with
the literature, with all concentration
factors between studies agreeing within
a factor of 2 to 3.
Previous studies also examined the
kinetics of heavy metal accumulation by
algae and in general show that uptake
was an extremely rapid phenomenon.
The results of the 24-hour experiments in
this study clearly confirmed the earlier
observations in this regard. The negative
results for the cadmium experiments
cannot be explained at this time.
One obvious manner in which the
present study extends previous work is
the calculation of concentration factors
for species of algae previously unstudied.
These data were obtained under identical
conditions and record both intraspecific
(in the case of Nostoc) and interspecific
differences in heavy metal accumulation
by algae. New data are provided on the
effects of culture age, and initial pH
-------
30-
I
I
to
O
20-
10-
"... Control
A ...Nostoc 586 (12 day)
O ...Chlamydomonas (12 day)
A ...Oscillatoria (12 day)
• ...U\otMx(12day)
12
Time (hours)
15
18
21
24
Figure 3. Uptake of cadmium by various algae.
20
10-
m... Control
&...NosiocS86(12day)
O...Chlamydomonas (12 day)
A... Oscillatoria (12 day)
•...Gleotrichia (40 day)
18
21
24
Time (hours)
Figure 4. Uptake of copper by various algae.
during the labelling period, on the accu-
mulation of heavy metals by algae.
The present study about doubles the
number of algae for which concentration
factors for cadmium have been deter-
mined. This is not only important to waste
treatment applications, but also to envi-
ronmental impact studies. Also note-
worthy is the close agreement of concen-
tration factors from the literature with
those of this study, with CFs on the order
of 103 common to both. What is not
immediately apparent is the generally
lower CFs for the blue-green algae. In
fact, three 10-day old cultures of blue-
green algae, Nostoc muscorum A, Nostoc H
and Schizothrix calcicola did not remove
cadmium significantly at any pH, while
only one green algae, Mougeotia. showed
such negative results. Although the total
number of species examined is small, the
present study suggests that green algae
are somewhat more efficient at accumu-
lating cadmium than the blue-green
algae.
Concentration factors for lead are gen-
erally on the order of 103 to 10* for all
algae studied. All the blue-green algae
screened were successful at removing
lead at least at one pH, while the diatom
Naviculapelliculosa and the green Chlor-
ella and Scenedesmus obliquus were
successful at accumulating lead at any
pH. Chlamydomonas proved to be the
most efficient at removing lead from
solution.
Mercury was again demonstrated to be
concentrated avidly by most species of
algae. Every organism screened in this
study removed mercury at least at one pH,
with concentration factors on the order of
103 and 104. Algae may be one of the
most effective means for removing this
element. Algae can reduce mercuric ion
toelemental mercury which is subsequently
volatilized to the atmosphere. The ques-
tion might arise whether the same
phenomenon occurred in these experi-
ments, giving artifically high concentra-
tion factors. Although the possibility
cannot be denied categorically, the short
time scale of these experiments (three
hours) and the quiescent conditions under
which the plates were held would argue
against loss of very much mercury to the
atmosphere. This is especially true since
most other studies employed aerated
cultures and a time scale of several days.
It has also been reported that the reducing
factor(s) were extracellular. Since the
algal cells in the present study were
washed and resuspended in distilled
water before introduction to the assay
plates, the concentration of reducing
factor(s) would be diminished, at least
initially. However, the phenomenon of
mercury reduction and volatilization by
algae clearly deserves further study.
Another contribution of this work was
the systematic study of the effect of pH on
heavy metal accumulation. The studies
cited from the literature were generally
field observations, during which the pH of
the surroundings varied naturally, or were
laboratory studies where the culture
media characteristically determined the
pH of metal uptake, and therefore, uptake
across a wide variety of pH conditions
could not be determined. In general, those
algae which are most proficient at re-
moving metals will remove them over a
wide pH range. For example, Chlamy-
domonas removes lead across a pH range
from 4 to 9 at about the same efficiency
(0.69-0.80) while the less effective alga
Mougeotia removes lead only at pH 9 and
-------
20-
• ...Control
O ...Chlamydomonas (72day)
A ...Nostoc 586 (12 day)
A ...Oscillatoria (12 day)
• ...UIothrixCr2ofay;
9 ...Spirogyra (12 day)
9 12 15 18 21 24
Time (hours)
Figure 5. Uptake of lead by various algae.
40-
5
30-
20-
10-
• ...Control
A ... Nostoc 586 (12 day)
O ...Chlamydomonas f/2 day)
A...Oscillatoria (12 day)
• ...Spirogyra (12 day)
3 6 9 12
Time (hours)
Figure 6. Uptake of mercury by various algae.
15
18
21
then only at an efficiency of 0.29. Clearly
Chlamydomonas is more competent at
removing lead from solution.
Other observations made during this
study tend to confirm and extend sugges-
tions made by earlier workers. It has been
hypothesized that the flagella of Platy-
monas subcordiformis provided the sites
for a significant fraction of the lead taken
up by this algae. While this hypothesis
was not specifically tested in the labora-
tory, the dramatic superiority shown by
Chlamydomonas in removing lead, as
compared to the other algae evaluated
combined with the fact that Chlamydo-
monas was the only flagellated form used,
argues for the importance of the flagella
as sites of lead accumulation.
Perhaps one of the most important
contributions of this work, however, was
the adaptation and development of micrc
titer equipment, especially the Titertek7
supernatant collection apparatus, to th
study of the problem of algal uptake c
heavy metals. The technique and proce
dures developed during the course of thi
study have already provided usable dat
on a relatively limited number of variables
Future work will no doubt utilize th
rapidity and sensitivity of the technique t
accumulate more data covering a wide
range of variables.
Recommendations
The remarkable ability of selected alga
to concentrate heavy metals on their ce
surfaces suggests that the use of inter
sive algal culture may be a very practic.
way to reclaim wastewater and/or re
cover useful quantities of metals. Severe
directions for future research and develop
ment are clearly indicated before thi
potential can be realized:
1. The glycocalyx—i.e., the mucopoly
saccharide and protein capsule-
surrounding all algae must be isolate
from metal-avid species and furthe
studied for its biochemical structun
exchange capacities, and biphasi
physical properties. With these dat
in hand, it is practical to search fo
organisms with glycocalyces havin
desirable properties for the adsorp
tion of metals.
2. If algal beds are to be maintained on
continuing basis, it will be necessar
to follow the reproductive capacity c
the organism(s) in the presence c
excessive levels of metal. In fact, i
may be necessary to devise schedule
for metal adsorption that are followei
by regeneration at low metal levels.
The present meander technolog
depends entirely on the presence o
naturally occurring wild algae, prob
ably growing as a mixed flora. Sinci
some of the species may have con
centration factors in excess of 1 x 10
under certain conditions, and other:
may not concentrate metal at all, i
appears profitable to encourage thi
former by selective algal farming
Simple enrichment culture tech
niques are feasible for the meande
manager.
3. A screening operation should bi
devised with the objectives of f indini
natural or induced mutants that a
have accumulation coefficients oni
or more orders or magnitude greate
than wild types, b) exhibit greate
selectivity for a particular metal ioi
than the wild types, and c) tend, ti
-------
30
I25
15-
^...Control
A...Nostoc 586 (12 day)
O...Chlamydomonas (12 day)
A...Oscillatoria (12 day)
•...UIothrix(72cteW
12
Time (hours)
15
18
—t—
21
24
Figure 7. Uptake of nickel by various algae.
25-
2CH
15-
10-
U... Control
A...Nostoc 586 (12 day)
O...Chlamydomonas/'72 day)
A...0scillatona (12 day)
• ...Spirogyra (12 day)
9 12 15
Time (hours/
18
21
24
meander beds. Simultaneously, it
must be determined whether or not it
is feasible to recycle the algal cells as
inoculum or feedstock after they have
been stripped of metal by chemical
washing.
6. Investigation of practical questions
regarding the suitability of metal-
stripped secondary sewage effluent
for agricultural purposes must be
examined. Conversely, the efficacy of
sewage as a dependable nutrient
source for algae has not been estab-
lished. Certainly, the presence of oil,
cyanates, solvents, etc., could be
expected to interfere with the pro-
ductive synthesis of the glycocalyx
adsorptive surface.
7. The effects of light, temperature, and
salt concentration have not been
evaluated on a continuously opera-
ting meander. Quantitative data have
not been collected on the optimum
output of glycocalyx because the
factors which stimulate it are essen-
tially unknown.
8. Future work should determine
whether or not an appropriate substi-
tute can be found for the algal cells in
the meander (aggregates or other
surfaces coated with semi-purified
glycocalyx, for example). This search
might provide a renewable and/or
strippable surface that would elimi-
nate some of the vagaries associated
with the maintenance of open algal
cultures.
Reference
Polikarpov, G. G. 1966. Radioecology of
aquatic organisms (Translated from
Russian by ScriptaTechnica). Reinhold,
New York. 314 p.
Figure 8. Uptake of zinc by various algae.
remain in their benthic form rather
than in their free-floating form. The
blue-green algae may be the better
choice for this work because they are
usually more metal-avid than green
algae, and because they are haploid.
The latter characteristic makes it
easier to induce mutations and to
select for variants than in diploid
organisms.
Almost no data are to be found
concerning the maintenance of beds
5.
of benthic algae on a continuous
basis. Experiments are needed to
learn the long-term consequences of
heavy metal accumulation in such
beds, to monitor detention and re-
lease of metals during chronic expo-
sures, and to study the detachment
of benthic cells coated with heavy
metals.
Methods must be devised for sys-
tematically discharging metals, or for
otherwise recovering them, from
. S. GOVERNMENT PRINTING OFFICE: 1983/659-095/1907
-------
J. Charles Jennett is presently with Clemson University. Clemson, SC 29631; J.
E. Smith and J. M. Hassett are with Syracuse University, Syracuse, NY 13210.
Hugh B. Durham is the EPA Project Officer (see below).
The complete report, entitled "Factors Influencing Metal A ccumu/ation by Algae,"
(Order No. PB 83-149 377; Cost: $14.50, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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