EPA-660/3-74-032
OCTOBER 1974
Ecological Research Series
2
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development,
U.S. Environmental Protection Agency, have been grouped into
five series. These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in
related fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ECOLOGICAL RESEARCH STUDIES
series. This series describes research on the effects of pollution
on humans, plant, and animal species, and materials. Problems
are assessed for their long- and short-term influences. Investigations
include formation, transport, and pathway studies to determine
the fate of pollutants and their effects. This work provides
the technical be.sis for setting standards to minimize undesirable
changes in living organisms in the aquatic, terrestrial and atmospheric
environments.
This report has been reviewed by the National Environmental
Research Center--Corvallis, and approved for publication. Mention
of trade names or commercial products does not constitute endorsement
or recommendation for use.
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EPA-660/3-74-032
October 1974
NUTRIENT INACTIVATION AS A LAKE RESTORATION PROCEDURE
LABORATORY INVESTIGATIONS
by
Spencer A. Peterson
William D. Sanvilie
Frank S. Stay
Charles F. Powers
Pacific Northwest Environmental Research Laboratory
National Environmental Research Center
Corvallis, Oregon
ROAP 21 AIY, Task 36
Program Element 1BA031
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97^30
_ ,j * * : __ ______ ______
sale by the Supennf^TOSiu ot TTocuments, US Government Printing Office
Washington D.C. 20402 - Stock No' 5501-00994
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PREFACE
The Federal Water Pollution Control Act Amendments of 1972, PL 92-500,
include the requirement that the Administrator of the United States
Environmental Protection Agency issue such information on methods,
processes, and procedures as may be appropriate to restore and
enhance the quality of the nation's publicly owned lakes [Subsection
304(i)]. The concept of in-lake nutrient inactivation, wherein a
critical nutrient is rendered unavailable through introduction of a
complexing additive to the lake, is a promising restorative technique
that has received limited attention in the United States and Europe.
The present study is designed to more thoroughly evaluate this concept
at the laboratory and pilot field scale levels, using a variety
of potential inactivant materials over a range of simulated and actual
operational conditions, to determine its value and potential as a
practical tool in lake management.
Although the authors assume full responsibility for the investigations
described in this report, the work could not have been carried out
without the able assistance of a number of other members of this
laboratory. In particular, the contributions of William Lauer in
the work on efficiency of inactivant materials; Terry Smith in the
toxicity studies; and Thomas Hamlin in the development of the sediment-
water column systems, are gratefully acknowledged.
Dr. Alan V. Nebeker of the EPA Western Fish Toxicology Laboratory in
Corvallis rendered valuable assistance in the design of the toxicity
studies, and provided us with laboratory populations of invertebrate
test organisms. Salmonid fish were kindly furnished by the U.S.
Bureau of Sports Fisheries Eagle Creek Fish Hatchery and the State
of Oregon Fall Creek and Roaring River Fish hatcheries.
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We also wish to thank the Wan Chang Teledyne Company, Albany, Oregon,
for supplying experimental quantities of zirconium refinery waste, crude
zirconium tetrachloride, and nuclear grade zirconyl chloride, the
latter for standards.
11
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CONTENTS
Page
Preface -ji
List of Figures v
List of Tables viii
Sections
I. Introduction 1
II. Summary 4
III. Conclusions 5
IV. Recommendations 7
V. Efficiency of Inactivant Materials 8
VI. Toxicity and Environmental Effects 44
VII. Stability and Duration of Effectiveness 77
VIII. Availability and Costs of Inactivants 112
IX. References "115
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FIGURES
No. Page
1. Phosphorus removal efficiency of zirconium 16
refinery waste in AAP medium and pond water.
2. Phosphorus removal efficiency of tungsten and 20
titanium in AAP medium.
3. Phosphorus removal efficiency of aluminum 21
sulfate in AAP medium and pond water.
4. Phosphorus removal efficiency of sodium 23
aluminate in AAP medium and pond water.
5. Phosphorus removal efficiency of zirconium 25
tetrachloride and zirconyl chloride in
AAP medium and pond water.
6. Phosphorus removal efficiency of lanthanum 35
rare earth chloride and lanthanum rare earth
carbonate in AAP medium and pond water.
7. Effect of pH on phosphorus removal by 37
lanthanum, zirconium, and aluminum in
AAP medium.
8. Effect of pH on phosphorus removal by 33
lanthanum, zirconium and aluminum in
pond water.
9. Percent survival of Daphnia magna 55
in four concentrations of sodium aluminate
over 96 hours.
10. Percent survival of Daphnia magna in four 53
concentrations of zirconium refinery waste over
96 hours.
11. Percent survival of Daphnia magna in four 59
concentrations of zirconium tetrachloride
over 96 hours.
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No. Page
12. Percent survival of Daphnia magna 61
in three concentrations of zirconium
tetrachloride during weeks 1-3 of 9-week
toxicity test.
13. Percent survival of Daphnia magna in three 62
concentrations of zirconium tetrachloride
during weeks 4-6 of 9-week toxicity test.
14. Percent survival of Daphnia magna in three 63
concentrations of zirconium tetrachloride during
weeks 6-9 of 9-week toxicity test.
15. Daphnia magna reproductive rate per individual 64
per week during 9-week zirconium tetrachloride
toxicity test.
16. Percent survival of Daphnia magna in four 65
concentrations of zirconyl chloride over 96
hours.
17. Percent survival of coho salmon in four 66
concentrations of lanthanum rare earth chloride
over 96 hours.
18. Percent survival of Daphnia magna in four 69
concentrations of lanthanum rare earth chloride
over 96 hours.
19. Jenkin corer tubes modified for laboratory 79
experiments.
20. Aerobic-anaerobic experimental set-up with 81
modified Jenkin tubes.
21. Autoanalyzer record demonstrating reproducibility of 85
duplicates for phosphorus analysis in small volume
(2.5 ml) samples.
22. Typical calibration curves for micro oxygen 89
meter.
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No. Page
23. Semi-micro combination pH probe adapter. 90
24. Plastic redox probe adapter for excluding 92
air from anaerobic samples.
25. Device for extruding sediment samples from 95
Jenkin coring tubes.
33
26. Jig for injecting P into sediment. 93
27. Total phosphorus concentration of an aerated 101
system before and after zirconium tetrachloride
addition with subsequent nitrogen purging.
28. Total soluble phosphorus concentration of 102
an aerated system before and after zirconium
tetrachloride addition with subsequent nitrogen purging.
29. Dissolved oxygen and pH in an aerated system 104
before and after zirconium tetrachloride
addition with subsequent nitrogen purging.
30. Total phosphorus concentration of an 105
anaerobic system before and after zirconium
tetrachloride addition with subsequent aeration.
31. Total soluble phosphorus concentration of an 107
anaerobic system before and after zirconium
tetrachloride addition with subsequent aeration.
32. Dissolved oxygen and pH in an anaerobic system 108
before and after zirconium tetrachloride addition
with subsequent aeration.
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TABLES
No. Page
1. Chemical composition of AAP culture medium. 10
2. Chemical composition of Cline's Pond #1 water 11
at the i:ime of jar tests.
3. Chemical analysis of zirconium refinery waste. 17
4. Results of algal assay tests on AAP medium treated 18
with zirconium refinery waste.
5. Results of algal assay tests on AAP medium 27
treated with sodium aluminate.
6. Results of algal assay tests on sodium 28
aluminate treated AAP medium in which phosphorus
was reconstituted.
7. Results of algal assay tests on AAP medium 29
treated with zirconium tetrachloride.
8. Results of algal assay tests on AAP medium 30
treated with zirconyl chloride.
9. Chemical composition of lanthanum rare earth 31
carbonate.
10. Chemical composition of lanthanum rare earth 32
chloride.
11. Results of algal assay tests on AAP medium 33
treated with lanthanum rare earth chloride.
12. Results of algal assay tests on lanthanum 36
rare earth chloride treated AAP medium
in which phosphorus was reconstituted.
13. Chemical composition of water used in toxicity 50
tests.
14. Dissolved aluminum concentrations, sodium 53
aluminats fish bioassav.
vm
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No. Page
15. Dissolved aluminum concentrations, sodium 54
aluminate Daphnia magna bioassay.
16. Average length/weight measurements of coho 55
salmon at termination of 96-hour zirconium
refinery waste bioassay.
17. Average length/weight measurements of coho 57
salmon at termination of 96-hour zirconium
tetrachloride bioassay.
18. Average length/weight measurements of coho 68
salmon at termination of 96-hour lanthanum
rare earth chloride bioassay.
19. Nitrogen-air pumping rates to experimental 82
columns as related to dissolved oxygen levels.
20. Results of replicate sample tests for total 86
phosphorus using the Technicon AutoAnalyzer
with 2.5 ml samples (Base = 0.50, C/A = 0.3333).
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I. INTRODUCTION
The Ecosystems Analysis and Methods Development Section of the
Eutrophication and Lake Restoration Branch (Program Element 1BA031)
is charged with the conduct of laboratory and field research on
aquatic ecosystsms to develop information relative to effective
prevention and control of eutrophication processes. The concept
of nutrient ina:tivation in eutrophication control arid lake restoration
appears to be relatively new, although it is essentially an extension
of existing wastewater and water supply treatment methodology.
Inactivants which have received the most attention relative to
treatment technology are Al(III), Fe(III), and Ca(II) all of
which react in water at various pH's to form a floe which may chemically
bond or physically adsorb soluble phosphorus while also entrapping
organic phosphorus to some degree. Of the three, Al (III) appears
to be the only one applicable to lakes, since Ca(II) is ineffective
in removing phosphorus at pH values less than 9 and Fe(III)
is undesirable because of its tendency to be reduced to the soluble
Fe(II) state (thereby resolubilizing phosphorus) under anaerobic
conditions. The latterr conditions are found frequently in the
hypolimnions of eutrophic lakes.
The first attempt to inactivate nutrients in an entire lake with
aluminum appears to have been an experiment in phosphate precipitation
1 2 3
at Lake Langsjon, Sweden, in 1968 ' ' . Results of alum application
to the lake surface were favorable, with lowered phosphorus concentration,
increased oxygen concentration in bottom waters, and decreased
phosphate release from bottom sediments.
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In 1970 Horseshoe Lake, Wisconsin, was treated experimentally
with alum . Results for this small, eutrophic lake were likewise
encouraging. Total phosphorus concentrations decreased, transparency
increased, nuisance algal blooms failed to appear, and dissolved
oxygen conditions improved. A few other small Wisconsin Lakes,
including Long, Snake, and Pickerel, have subsequently been treated
with aluminum compounds and preliminary results appear to be similar
5
to those for Horseshoe Lake .
In 1971 a one acre (0.40 ha) pond near Corvallis, Oregon was treated
with sodium aluminate . Although overall phosphorus concentrations
were not greatly depressed, improvement in the pond during the following
summer and fall, as compared with previous years, was clearly evident.
There was a definite decrease in nuisance algae production and associated
symptoms.
The encouraging results obtained in this earlier work, and the need
for practical methods of controlling eutrophication in lakes where
high water and sediment nutrient levels are encountered, made
it appear worthwhile to investigate phosphorus inactivation in
greater detail. Laboratory and field studies were designed to
evaluate the suitability of a number of candidate materials
for use in natural waters. The objectives were to determine (1)
efficiency of each as a phosphorus inactivant, (2) possible toxicological
or other adverse environmental effects related to the inactivant
material, (3) stability of the initial result effected by treatment
and (4) beneficial limnological effects resulting from phosphorus
inactivation. Iron and calcium were not considered because of
the unsuitable characteristics previously mentioned. In all,
nine materials have been screened, consisting of eight metal
salts and a crude waste product from a zirconium refinery. The
metal salts are zirconium tetrachloride, zirconyl chloride, sodium
aluminate, aluminum sulfate (alum), lanthanum rare earth chloride,
lanthanum rare earth carbonate, sodium tungstate, and titanium sulfate.
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Work to date has concentrated on laboratory investigations relating
to the first three objectives. Information developed on the
efficiency, toxicity and environmental consequences, and stability
of the inactivation effects has been applied to the design of a
follow-up pilot scale field evaluation, which was initiated in
March 1974 at our Cline's Pond test site. Results of that phase
of the study will be presented in a subsequent report.
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II. SUMMARY
Compounds of certain metals are known to be capable of complex!ng
phosphate ions, thereby removing them from solution. The application
of this principle to the control of phosphorus levels in eutrophic
lakes has been subjected to laboratory investigation in the present
study. Salts of lanthanum, zirconium, and aluminum were found
to effectively remove phosphorus from laboratory growth medium and
natural pond water, with resulting depression of algal production.
Toxicity to fishes and aquatic invertebrates was minimal, but the
tests demonstrated that some components of metals salts may have
adverse effects. The stability and duration of phosphorus inactivation
is being studied in laboratory-scale water-sediment systems,
under aerobic and anaerobic conditions. These experiments
are expected to elucidate the effect of inactivant-phosphate
precipitates on sedir-.!.t-"''ater phosphorus interchange. Preliminary
results indicate that zirconium precipitates phosphorus from
the water and holds it at low levels.
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III. CONCLUSIONS
Compounds of lanthanum, zirconium, aluminum, tungsten, and
titanium were capable of removing phosphorus from pond water
and algal growth medium in the laboratory.
Based on molar ratios, the lanthanum rare earth mixtures were the most
efficient phosphorus inactivants, followed by zirconium and aluminum,
in that order.
The tungsten arid titanium compounds tested did not remove
phosphorus in sufficient quantity to merit further consideration
as practical nutrient inactivants.
Zirconium and lanthanum rare earth mixtures exhibited optimum
performance within pH ranges commonly encountered in eutrophic
lakes, whereas optimum phosphorus removal with aluminum was at
a lower and corsiderably narrower pH range rendering it less
appropriate for application to field situations.
Algal assays demonstrated that lanthanum rare earth chloride, zirconium,
and aluminum depressed algal growth in both AAP medium and pond
water.
Reconstitution of phosphate to the AAP culture medium generally
resulted in increased algal biomass approaching theoretical yields.
Available information indicates that zirconium and rare earths
supplies and reserves are sufficient to make feasible their use
in selected lake restoration activities, and that costs would not
be prohibitive.
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Toxicity studies using salmonid fish and cladocerans revealed
severe detrimental effects only with lanthanum rare earth chloride,
and in that case it is believed that the observed mortalities
resulted from a component of the compound other than lanthanum.
Results of preliminary tests with zirconium tetrachloride to
determine the extent and stability of phosphorus inactivation in
laboratory microcosms warrant further investigation.
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IV. RECOMMENDATIONS
Additional potential inactivants such as fly ash, volcanic ash,
clay materials;, and other metal salts alone and in combination
should be tested for efficiency, toxic effects and treatment stability.
In view of it;; high efficiency in removing phosphorus, lanthanum should
be subjected 1:0 further testing, particularly with respect to toxic
effects.
Laboratory studies on permanency of inactivation and effect on
sediment-water phosphorus interchange should be continued to
produce estimates of long-term effects.
Additional pi'ot scale field testing should be pursued as quickly
as possible, both to enhance and verify information developed
in the laboratory.
Experiments should be designed and initiated to determine the
availability of inactivated phosphorus to macrophytes as well as
to algae.
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V. EFFICIENCY OF INACTIVANT MATERIALS
OBJECTIVES AND APPROACH
Initial laboratory studies involved "jar tests" in which
candidate inactivant materials were screened to determine their
phosphorus complexing capacities. These tests included
determination of the phosphorus removal efficiency of the
inactivants at various pH levels.
In the jar tests, precipitated inactivant-phosphate phosphorus
(PO^-P) compounds were separated from the water by filtration,
and phosphorus analyses performed on the filtrate to determine
the phosphorus residual. The biological availability of the
residual phosphorus was assessed by the algal assay procedure (AAP).
Algal assays were also conducted to determine, through reconstituting
phosphorus to inactivated media, whether other growth-limiting
nutrients, in addition to phosphorus, had been removed.
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METHODS, MATERIALS, AND EQUIPMENT
General
All chemicals were of reagent grade quality or better unless
otherwise stated. Hydrochloric acid (HC1) and sodium hydroxide
(NaOH) were used for all pH adjustments and glass double distilled
water was used tD prepare all solutions.
Measurements of j3H were made with Beckman Electromate and Beckman
Zeromatic meters.* Phosphorus analyses were performed both manually
using the single reagent ascorbic acid technique and by automated
procedures using a Technicon AutoAnalyzer.
Sulfuric acid-persulfate digestion was used in the total phosphorus
o
analyses. All determinations followed standard EPA methodology.
A Coulter electronic particle counter was used for total cell
counts and average cell volume determinations in the algal assay
tests.
Phosphorus Removal Experiments ("Jar Tests")
Batch-type "jar -tests" were used as the first step in screening
inactivant materials. Intital tests were carried out on
AAP culture medium, the chemical composition of which is given in
Table 1. Potential inactivants which performed well in AAP medium
were tested further in water from Cline's Pond #1 (henceforth referred
to as pond water.). Chemical composition of the pond water at the time
of the jar tests is given in Table 2.
*Mention of commercial products by EPA does not constitute an endorsement
or recommendation for their use.
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Table 1
CHEMICAL COMPOSITION OF
AAP CULTURE MEDIUM
Compound
Concentration
(mg/1)
Compound
Concentration
(yg/D
NaNOg
K2HP04
MgCl2
MgS04
CaCl2
NaHCOo
7H20
25.5
1.0
5.7
14.7
4.4
15.0
H3B03
MnCl2
ZnCl2
CoClo
Na2Mo04
FeCl3
Na2EDTA
2H20
185.5
264.2
32.7
0.7
0.0
7.2
96.0
300.0
10
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Table 2
Chemical Composition of Cline's Pond #1 Water (mg/1)
at the Time of Jar Tests
Total - P 1.36
Orthophosphate - P 0.43
Ammonia - N 0.21
Nitrite - N 0.01
Nitrate - N 0.18
Total Kjeldahl - N 0.82
Chloride 5.00
Total Inorganic Carbon 3.30
Alkalinity (eq. CaC03) 31.0
Dissolved Iron 0.28
Total Hardness 36.3
Conductivity 96.0 ymho/cm
11
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Known chemical characteristics of the inactivants permitted calculation
of the theoretical quantity necessary to achieve 100 percent phosphorus
(P04-P) removal. Following calculation, six 500 ml samples, with
various concentrations of inactivant, bracketing the estimated 100
percent phosphorus removal concentrations, were stirred at 100 rpm on
a Phipps and Bird 6-place mixer. A solution of inactivant (always
less than 0.5 percent of the volume of the test solution) was added
when stirring began and the pH was adjusted to 7.0. The mixture
was stirred for 5 minutes more, and the stirring rate slowed to 20
rpm for an additional 30 minutes. Mixing was then terminated to
allow a 30-minute settling period, after which the supernate was
filtered through a prewashed 0.45 u filter. The filtrate was
analyzed for residual orthophosphate-phosphorus. (Note: Dissolved
inactivant concentrations were not measured because sufficiently
sensitive analytical methodology was not available. Therefore,
inactivant concentrations as expressed in this report refer only to
quantities of materials added).
The above procedure was varied slightly in the tests on sodium
aluminate. With this material efficiency of phosphorus removal was
variable when pH was adjusted downward to 7.0, and was less than
expected when compared to alum. Initial downward adjustment of the
pH to 5.0, followed by readjustment back to 7.0, resulted in less
variation and increased phosphorus removal.
The results of these broad-spectrum tests were examined to determine
the range of inactivant concentration over which the desired amount
of phosphorus removal occurred; a second series was then run over
a narrower concentration range. Results of these tests were plotted
to show that the percent phosphorus removal was a function of the
inactivant-to-phosphate molar ratio. This ratio was calculated by
dividing molar quantity per liter of the inactivant added by the
initial molar concentration of phosphorus. Expressed in this manner
the phosphorus removal efficiencies of different inactivants or
different concentrations of the same inactivant are directly comparable.
12
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Algal Assay Experiments
The second step in the screening process involved the use of the
standard Algal Assay Procedure . ,
phosphorus-inactivated AAP medium.
standard Algal Assay Procedure . Assays were conducted only on
Two hundred milliliters of filtrate from the inactivated AAP medium
were placed in a sterilized 500 ml Erlenmeyer flask and inoculated
with 1 ml of A Selenastrum capricornutum culture. The inoculum was
prepared by centrifuging a 7-day-old stock culture of S_. capricornutum,
decanting the supernate, washing the cells in a 15 mg/1 sodium
bicarbonate solution, centrifuging again, and decanting the supernate.
This was repeated twice, after which the inoculum was counted and
diluted to approximately 200,000 cells/ml. The inoculated samples
were incubated 14 days at 24°C ± 1°C and approximately 4300 lux
(1300 yW/cm )(i on a rotary shaker at 100 oscillations/min. One
ml of sample was collected for total cell count and average cell
volume determination on days 3, 4, 5, 6, 7, 10, 12 and 14 of the
incubation period.
Effect of pH on Phosphorus Removal
Tests were conducted with sodium aluminate, zirconium tetrachloride
and lanthanum rare earth chloride,, using both AAP medium
and pond water, to determine the effect of pH on the phosphorus
removal efficiency of the inactivant. A 4-liter container
of test medium (either AAP medium or pond water) was adjusted
to pH 2.0 with HC1. This was used as a stock solution for
a The energy level output of a bank of six 48 inch "cool white"
fluorescent lamps (GE 40 watt, @ 60 Hz) was approximately 1300
yw/cm2 (range, 380-760 nm) at a distance of 26 3/4 inches, as
measured with an ISCO Model SRC spectroradiometer. Using the
same measurement geometry, a Weston Model 756 Illumination Meter
read 400 footcandles. All reflecting surfaces were matte white.
Therefore, utilizing a calibrated illumination meter with a footcandle
readout, one may, by adjusting the height?of the lights, achieve
a known energy level output of 1300 yw/cm .
13
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tests on a single inactivant material. One hundred ml of medium
was pipetted into a 250 ml beaker, a quantity of inactivant
material estimated to achieve about 90 percent phosphate removal
added, and the mixture stirred. The remaining stock test solution
was then adjusted to pH 3.0 with NaOH, and a second 100 ml
aliquot pipetted into a beaker, inactivant added, and the mixture
stirred. This procedure was repeated for each whole pH unit
through 11.0. The supernatant portion of each 100 ml aliquot
was then filtered through a 0.45 y membrane filter, and analyzed
for residual phosphorus.
14
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EXPERIMENTAL RESULTS
Zirconium Refinery Waste
Jar Tests -
The zirconium refinery waste used in these experiments was a
heterogeneous irixture containing a number of metals and other
elements in addition to zirconium. An analysis provided by the
refinery is presented in Table 3. It should be noted that the
waste material analyzed was kiln dried at 300°C prior to analysis
and therefore the oxides of the elements appear in the table. The
non-kiln dried waste used in the experiments contained halogens
in addition to the oxidized species. Because of this heterogeneity
the relationship of refinery waste to phosphorus removed is expressed
on a weight basis rather than as molar ratio as has been done for
other inactivants tested. It was decided to conduct inactivation
tests using both wet waste (65% water) and wet waste dried at 105°C
for 24 hours. Drying the waste did not greatly affect the amount
of phosphorus removed, although in both media the wet waste did
remove more phosphorus than the dried waste (Figure 1). The differences
in removal were much less significant in pond water than in AAP
medium.
Algal Assays -
Results of algsl assay tests on AAP medium treated with seven different
concentrations of zirconium refinery waste are given in Table 4.
The algal dry weight yields were higher than expected for the measured
quantities of residual phosphorus. Although the excessive yields
cannot be explained by the available data, it seems evident that
all the residual phosphorus was in a form available for uptake by
the test organisms. The observed growth further implies that
toxic or other inhibitory effects were not associated with the inactivant,
15
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Table 3
Chemical Analysis of Zirconium Refinery Waste*
Compound Percent
(Zr+Hf)02 55.30
(Cb+Ta)02 0.01
A1203 1.63
Si04 21.97
MgO 10.50
CaO 11.94
Fe2°3 3.34
104.69
*Kiln dried at 300°C.
17
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Table 4
Results of Algal Assay Tests on AAP Medium
Treated with Zirconium Refinery Waste
Waste Residual P04-P Waste:P04-P Cell count Cell Dry Wt.
(g/1) (mg P/l) Weight Ratio Cells/mlxlO4 (mg/1)
(x 103)
0.0 0.215 0.0 686.1 94.7
0.2 0.075 0.9 231.4 48.0
0.6 0.018 2.8 59.0 12.7
1.0 0.008 4.6 18.9 4.7
4.0 0.001 18.6 0.8 0.2
10.0 0.001 46.5 0.6 0.2
15.0 0.001 69.8 1.6 0.4
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Tungsten and Titanium
Jar Tests -
The maximum amount of phosphorus removed from AAP medium with sodium
tungstate was 53 percent at a tungsten to phosphorus molar ratio of
8.4. As can be seen from the curve, no significant increase in
phosphorus removal occurred at higher molar ratios (Figure 2).
Titanium sulfate (basic) was less efficient than sodium tungstate
at the lower rrolar ratios, but resulted in much higher maximum
phosphorus reiroval. Maximum removal was 80 percent at a titanium
to phosphorus molar ratio of 28.6. Molar ratios greater than 28.6
did not appear to significantly increase the amount of phosphorus
removed (Figure 2).
Aluminum Sulfate (Alum)
Jar Tests -
Aluminum sulfate was slightly more efficient in removing phosphorus
from AAP medium than from Cline's Pond water (Figure 3). Maximum
phosphorus removal in both media was 95 percent at an Al(III):
phosphorus molar ratio of 3 in AAP medium and 4 in pond water.
Molar ratios greater than these did not result in a significant
decrease in residual phosphorus.
19
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Sodium Aluminate
Jar Tests -
Two different experiments were conducted with sodium aluminate.
In one the pH of the treated solution was adjusted down to 5.0
and then readjusted to 7.0. In the other the pH was simply
adjusted down to 7.0. Results are summarized in Figure 4, where it
will be noted that lowering the pH to 5.0 before neutralizing resulted
in increased phosphorus removal. Results differed, however, between AAP
medium and pond water: the relationship between phosphorus removal
and inactivant concentration was linear in AAP medium, but non-
linear in pond water. When the pH was simply adjusted down to
7.0, the non-linear relationship was found in both AAP medium and
pond water. Not only was efficiency of phosphorus removal lower,
but results were less consistent than when pH was first lowered
to 5.0.
Algal Assays -
Algal assay growth response to the filtrates from the sodium aluminate
experiments indicated that the residual phosphorus existed in an
available form, that is, the test organism was able to assimilate
it (Table 5).
Additional filtrates were reconstituted with phosphorus to concentrations
approximately the same as in control samples. These would have been
expected to produce about the same biomass as the controls, assuming
(1) no toxic effects and (2) that phosphorus was the only growth-
limiting nutrient removed by the sodium aluminate. In the case of
treatment with 0.99 mg Al/1 , algal biomass produced was equal to the
calculated theoretical yield (Table 6). However, where 1.32 mg Al/1
was added to the growth medium, reconstitution of the phosphorus
content failed to produce the expected growth. These disparate
results will be the subject of future investigation, particularly
with regard to assumptions (1) and (2), above.
22
-------
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Zirconium
Jar Tests -
Testing was carried out on two forms of zirconium: zirconium
tetrachloride (ZrCl.) and zirconyl chloride (ZrOCl? 8HpO).
Reagent grade zirconium tetrachloride and zirconyl chloride
were used in the experiment with AAP medium. Both zirconium
forms used in the experiments on pond water were of a less
refined quality; the zirconium tetrachloride contained from
0.1 to 2.0 percent impurities. The zirconyl chloride was
precipitated from a saturated water solution of the less pure
zirconium tetrachloride and thus contained some impurities.
Zirconium tetrachloride (reagent grade) removed 100 percent
of the phosphorus in AAP medium at a Zr(IV)/P molar ratio of
4.3 (Figure 5). Results with zirconyl chloride (reagent grade)
were very similar, but zirconium tetrachloride appeared to
be somewhat more efficient.
Both zirconium inactivants were more effective in pond water
than in AAP medium. Zirconyl chloride (crude) appeared to
be a slightly more efficient phosphorus inactivant than zirconium
tetrachloride (crude) in pond water.
Algal Assays -
Algal assay growth yields on the filtrates from zirconium tetrachloride
and zirconyl chloride jar tests (Tables 7 and 8) were proportional
to the amount of residual phosphorus present in the filtrate, indicating
that the residual phosphorus was in a form usable by the test
organisms. The single exception was a marked decrease in the dry
weight yield in samples treated with 0.25 mg Zr/1 zirconyl chloride.
24
-------
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This decrease in yield did not appear to be the result of a
toxic effect since samples treated at higher concentrations
(1 mg Zr/1) yielded greater dry weights. A like decrease did
not occur in samples treated with zirconium tetrachloride at
the same Zr concentration.
26
-------
Table 5
Results of Algal Assay Tests on AAP Medium
Treated with Sodium Aluminate
NaA102 Residual P04~P Cation: P04~P Cell Count Cell Dry Wt.
(mg Al/1) (mg P/l) Molar Ratio (Cells,/mlx!04) (mg/1)
0.00 0.184 0.0 285.34 32.73
0.66 0.014 4.1 34.55 8.75
0.99 0.008 6.2 0.32 0.06
1.15 0.002 7.2 0.12 0.03
1.32 0.003 8.3 0.13 0.02
1.65 0.001 10.3 0.03 0.00
27
-------
Table 6
Results of Algal Assay Tests on Sodium Aluminate-Treated
AAP Medium in Which Phosphorus was Reconstituted
NaA102 Residual P044-P Cation: P04-P Cell Count Cell Dry Wt.
(mg Al/1) (mg P/l) Molar Ratio (Cells/mlxlO4) (mg/1)
0.00 0.180 0.0 285.34 32.72
0.99 0.190 6.2 265.14 39.83
1.32 0.180 8.3 5.96 1.90
28
-------
Table 7
Results of Algal Assay Tests on AAP Medium Treated
with Zirconium Tetrachloride
ZrCl4 Residual P04-P Cation: P04-P Cell Count Cell Dry Wt.
(mg Zr/1) (mg P/l) Molar Ratio (Cells/mlxlO4) (mg/1)
0.00
0.25
1.00
2.00
3.00
4.00
5.00
0.163
0.135
0.036
0.004
0.0
0.0
0.0
0.0
0.5
2.1
4.2
6.3
8.4
10.5
403.5
328.3
118.1
0.3
0.2
0.2
0.2
54.35
45.48
21.73
0.07
0.03
0.03
0.03
29
-------
Table 8
Results of Algal Assay Tests on AAP Medium Treated
with Zirconyl Chloride
ZrOCl2
(mg Zr/1)
0.00
0.25
0.25
1.00
1.00
3.0
4.0
5.0
7.0
Residual PO.-P
(mg P/l)
0.155
0.120
0.155
0.049
0.039
0.0
0.0
0.0
0.0
Cation: P04-P
Molar Ratio
0.0
0.5
0.5
2.2
2.2
6.6
8.8
11.0
15.3
Cell Count
(cells/mlxlO4)
482.04
7.20
1.67
134.23
105.42
0.08
0.08
0.08
0.09
Cell Dry Wt
(mg/1)
54.32
1.13
0.22
16.61
12.70
0.01
0.01
0.01
0.01
30
-------
Table 9
Chemical Composition of Lanthanum Rare Earth Carbonate.
Ratio of Rare Earth Oxide/Total Rare Earth Oxides (REO)*
La2°3
Nd00_
2 3
Pr6°n
Ce(L
2
Other REO
65%
27%
7%
1%
1%
Na20
CaO
Cl
FeA
2 3
Loss on Ignition
.10%
.05%
.25%
.03%
33.00%
*Total REO = 65% of solids
31
-------
Table 10
Chemical Composition of Lanthanum Rare Earth Chloride.
Ratio of Rare Earth Oxide/Total Rare Earth Oxides (RED)*
La 0
Ce02
Nd2°3
Pr6°ll
Other REO
60.0%
15.0%
17.5%
7.0%
0.5%
Fe 0
CaO+SrO
Na20
(Pb+V+Ni+Cu)
MgO
Cl
0.02 %
1.00%
0.50%
0.01%
0.25%
25.00%
*Total REO = 46% of solids
32
-------
Table 11
Results of Algal Assay Tests on AAP
Medium Treated with Lanthanum Rare Earth Chloride
LaRECl Residual P04-P Cation: P04-P Cell Count Cell Dry Wt.
(mg/1) (nig P/l) Molar Ratio (Cells/mlxlO4) (mg/ml)
0.00 0.185 0.00 285.34 32.72
0.25 0.150 0.12 271.42 33.77
1.00 0.100 0.47 146.78 18.69
1.50 0.103 0.71 138.82 20.89
2.00 0.015 0.94 41.19 6.70
33
-------
Lanthanum
Jar Tests -
Testing was carried out on lanthanum rare earth carbonate and
lanthanum rare earth chloride, the chemical compositions of
which are given in Tables 9 and 10. Because the two compounds are
mixtures of rare earths, the molar ratios as presented represent the
ratio of the sum of the individual rare earth molar concentrations to
the phosphate-phosphorus molar concentration of the test medium.
Lanthanum rare earth carbonate is only slightly soluble in water,
and that used in this experiment was dissolved in dilute HC1 (pH 2.0)
before addition to the test medium. Both the carbonate treated with
HC1 and chloride salts removed 100 percent of the phosphorus in
MP medium and pond water, at a cation: phosphate-phosphorus molar
ratio of approximately 0.9 - 1.0 (Figure 6).
Algal Assays -
Assays were conducted only on lanthanum rare earth chloride. Results
are summarized in Table 11. Assays included tests on filtrates in
which the phosphorus concentrations had been readjusted to approximately
that of the control (Table 12).
34
-------
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Table 12
Results of Algal Assay Tests on Lanthanum Rare Earth
Chloride-Treated AAP Medium in Which Phosphorus was Reconstituted
LaRECl P04-P Cation: P04~P Cell Count Cell Dry Wt.
(mg/1) (mg P/l) Molar Ratio (Cells/mlxlO4) (rag/1)
0.00 0.185 0.0 285.34 32.72
1.0 0.180 0.47 418.98 52.23
2.0 0.195 0.94 263.03 27.29
36
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With the exception of the sample which received 0.25 mg/1 LaRECl, the
dry weight yields of the inactivated samples were less than those
of the control (Table 11). The biomass yields from filtrates in which
phosphorus was reconstituted showed mixed results (Table 12). The
sample which was treated with 1 mg/1 lanthanum rare earth chloride (LREC)
produced an unexpectedly high dry weight yield after reconstitution
which has not been explained. The results do show, however, that
any residual inactivant was non-toxic to the test organism.
The sample treated at 2 mg LREC and reconstituted with phosphorus
did produce a somewhat lower dry weight yield than the control,
however, it was well within the ±20% accuracy of the algal
assay and thus within the expected range. Again, this indicates
the absence of a toxicant.
Effect of pH on Inactivant Efficiency
The data obtained from the experiments to determine the optimum pH
for phosphorus removal by Al (III), Zr (IV), and La-rare earths are
presented in figures 7 and 8.
The concentrations of inactivants used in AAP medium (Figure 7) were
2.4 x 10"5M Al, 1.2 x 10"5 M Zr, and 1.0 x 10"5 M La-rare earths.
Concentrations used in pond water (Figure 8) were 12.2 x 10 M Al,
3.2 x 10"5 M Zr, and 1.9 x 10"5 M La-rare earths.
The pH range for optimum phosphorus removal by aluminum was quite
narrow. Minimum residual phosphorus concentrations occurred at pH
5 in AAP medium and between pH 4 and 6 in pond water. Residual
phosphorus concentrations increased sharply above and below these
pH values.
39
-------
The most effective pH range for phosphorus removal by zirconium
was 4 to 6 in AAP medium and 3 to 8 in pond water. In AAP medium
residual phosphorus rose gradually between pH 6 and 9 and increased
sharply above pH 9. In pond water a large increase occurred above
pH 8.
The optimum pH range for phosphorus removal by lanthanum was between
6 and 9 in AAP medium and between 6 and 10 in pond water. At pH
values above and below these ranges the amount of residual phosphorus
increased sharply.
40
-------
SUMMARY AND DISCUSSION OF PRELIMINARY SCREENING RESULTS
Aluminum sulfate (alum), sodium aluminate, zirconium tetrachloride,
zirconyl chloride, lanthanum rare earth chloride, and lanthanum
rare earth carbonate have all proven to be efficient phosphorus
inactivants. All were capable of removing 100 percent of the phosphorus
contained in the test media, if added in sufficient quantity, except
aluminum sulfate which removed 96 percent.
Relationships between inactivant added and phosphorus removed were
sometimes linear and sometimes curve! inear. It appears likely that
a linear relationship is indicative of an actual chemical reaction
involving the inactivant and phosphorus while a curvel inear relationship
would be associated with phosphorus removal by a sorption process.
The rationale for this is as follows.
During a chemical reaction such as
AB ^ A + 13
where A = inactivant species,
B = phosphorus species, and
AB = inactivant-phosphorus compound,
a constant relationship,
Ksp =
where K = solubility product, and
[ ] = molar concentration,
would exist, according to the law of mass action. The amount of
phosphorus, [B] , in solution would be equal to
KSP -T5T
which results in an inverse linear relationship between [B] and [A].
41
-------
During an adsorption reaction the relationship can be expressed
by the Freudnlich isotherm equation
* = kCrT , or C = (-. )n
m mk
where = amount of phosphorus removed per unit weight of adsorbent,
C = concentration of phosphorus in solution after adsorption, and
k and n = constants (n > 1).
Expressed graphically, this equation results in a curve!inear
relationship.
Of the inactivants tested, the two lanthanum rare earth mixtures removed
phosphorus from solution at the lowest inactivant to phosphorus molar
ratio, with 100 percent removal in both AAP medium and pond water occurring
at a ratio of approximately 0.9 to 1.0. The relationship was linear and
has been observed by others at much higher phosphorus concentrations. '
In those studies 100 percent phosphorus removal was obtained at
a cation: phosphate-phosphorus ratio of about 0.9, as was the case in our
_|__L_|_
experiments. A chemical reaction between La and a combination
of HPO^ " + P04 " is strongly suggested. ' Further, the similarity
of our results and those of others on media of very different chemical
compositions implies that phosphorus removal by lanthanum is not
greatly affected by the presence of contaminants.
Zirconyl chloride and zirconium tetrachloride were next in efficiency,
with 100 percent removal at molar ratios of 2.1 and 3.1, respectively.
A curve!inear relationship existed between these two compounds and
phosphorus removed, suggesting that phosphorus removal was by some
!2
process other than a chemical reaction, such as sorption or occlusion.
42
-------
Zirconium refinery wastes were required in much larger quantities
than the refined products to achieve comparable phosphorus removal
(Note that in Figure 1 the ratios are expressed in terms of weight
3
x 10 ). It was further noted that the wet waste product removed
more phosphorus than an equivalent amount of dried product. This
may have been conversion of a small fraction of the Zr (IV)
species to zirconium oxides during the drying process. Zirconium
dioxide is nearly insoluble in water and probably is not an effective
1 ?
phosphorus inactivant.
Greater quantities of aluminum sulfate (alum) and sodium aluminate
were required than zirconium tetrachloride and zirconyl chloride.
A molar ratio of 7.0 was necessary for 100 percent phosphorus
removal with sodium aluminate, while aluminum sulfate removed
95 percent of the phosphorus at a molar ratio of 3.0. Although
the 95 percent removal figure could not be exceeded with alum
its removal efficiency on a molar basis was better than for
sodium aluminate. The slightly greater effectiveness of both
aluminum compounds in AAP medium than in pond water probably
resulted from the difference in chemical composition of the
two media and the different concentration of inactivant used
913
in each experiment. ' With the exception of sodium aluminate
in AAP medium, a curvelinear relationship resulted between
aluminum added and phosphorus removed, suggesting that at pH
7.0 phosphorus removal was by some process other than chemical
reaction. The linear response by sodium aluminate in AAP
medium cannot be explained from these data.
Algal assay experiments showed that when less than 100 percent of the
ortho-phosphate phosphorus was removed from solution by inactivation,
the residual was available for uptake by the test alga. It is not
clear, however, whether the phosphorus passing through the 0.45 y
filter was not bonded to the inactivant or whether it was usable
by the algae in spite of being bonded.
43
-------
VI. TOXICITY AND ENVIRONMENTAL EFFECTS
OBJECTIVES AND APPROACH
Candidate materials which satisfactorily passed the initial screening
tests were next required to undergo testing for the determination
of possible adverse environmental effects, particularly toxicity
to aquatic fauna. The primary objectives were to examine organisms
which would be representative of the natural system and various
levels in the food web. If toxicity was demonstrated by an inactivant
during the tests this would have to be taken into consideration
before any subsequent application.
The toxicity tests were designed to evaluate the effects of the
inactivants under the most extreme environmental conditions. Static
rather than continuous flow systems were used, on the premise that
static systems would provide environmental conditions more stringent
than the organisms would be expected to encounter. The fish in particular
were under increased stress because of the absence of flowing water
and the confined conditions of the testing chambers. All the test
organisms were constantly exposed to quantities of inactivant-
phosphorus precipitant greater than those which they would likely
encounter under natural conditions. As noted for the jar tests, dissolved
inactivant concentrations could not be satisfactorily measured, and,
unless noted, concentrations refer only to quantities added.
Tests consisted of 96-hour, one generation bioassays using salmonid fish
and cladocerans (Daphnia magna), and 9-week, three generation bioassays
on £. magna only. Additional tests are planned for the larva of the benthic
midge Paratanytarsus sp; therefore, when all tests are completed, organisms
from three critical portions of the aquatic ecosystem will have been
subjected to inactivant stress. The midge larvae fish and cladocerans
will represent the benthos nekton, and zooplankton communities, respectively.
44
-------
METHODS
96-Hour Tests
Fish -
Fish bioassays were conducted in accordance with the Static Bioassay
14
described in Standard Methods, 13th edition . Test fish were
obtained from local fish hatcheries at Eagle Creek, Fall Creek,
and Roaring River. The tests were conducted with specimens
of Oncorhynchus tshawytscha (chinook salmon), Oncorhynchus kisutch
(coho or silver salmon), and Sal mo gairdneri (rainbow trout).
Species were not mixed in a given test.
Fish were transported from the hatcheries to our laboratory in
aerated hatchery water, then placed in a 10°C environmental room
to acclimate for 24 hours before transfer to a holding tank supplied
with carbon-filtered tap water. Dissolved oxygen levels were maintained
at 8-9 mg/1. The fish were provided with commercial fish food daily
in amounts such that a minimal residue remained the following day.
All fish were allowed to acclimate for a period of 14 days and were
not fed for two days prior to the initiation of testing. The toxicity
tests were conducted at 10°C. Twenty-liter wide-mouth soft-glass containers
were filled with 15 liters of carbon-filtered tap water, and the inactivant
added at concentrations 4 to 10 times expected operational levels.
Because of the basic nature of the aluminum compound and the extreme
acidity of the zirconium compounds, it was necessary to neutralize
the mixtures to pH 7.0 ± 0.2 with reagent grade sodium hydroxide
45
-------
or hydrochloric acid. The tests consisted of duplicates of the
controls and the four different additions of the material being
examined. Five fish were used in each of two containers at each
concentration, and for each control. Daily observations were made
on the general behavior and mortality of the fish.
TL (mean tolerance limits) values were determined from the percent
survival of the test organisms over the 96-hour test period. The
TL is defined as the concentration of toxicant at which 50 percent
of the test organisms survive a preselected time period. For example,
the 96-hour TL is the concentration at which 50% of the organisms
are alive after 96 hours. The values are determined graphically
by extrapolation between any two successive concentrations in
which one value is above the 50% survival value and one is below.
This is illustrated in Figure 12.
Cladocera -
The test used is one developed by the EPA National Water Quality
Laboratory, Duluth, Minnesota, for pesticide testing. A clone of
Daphnia magna (Straus) was kept in well water at room temperature
(22° ± 3°C), with 16-hour light and 8-hour dark photoperiods. Well
water from the EPA Western Fish Toxicology Station, Corvallis, Oregon,
was used as a test medium because of the extreme sensitivity
of these organisms to chlorine and its derivatives. Stock cultures
were maintained in one gallon soft-glass jars and fed a mixture
of ground nettle powder, water, and commercial fish pellets
twice weekly.
46
-------
Tests were conducted in a manner similar to the 96-hour fish
bioassays. Four hundred ml of well water were added to 600 ml
acid-washed Griffin beakers. The inactivant was added to each
beaker from a fresh stock solution, and the mixture neutralized
with either hydrochloric acid or sodium hydroxide to pH 7.0 ± 0.2.
Reagent grade sodium aluminate was used in the toxicity tests
on aluminum. The zirconium compounds were the "crude" forms,
containing less than two percent impurities, as used in the
"jar tests." Additions as presented in this text were not
corrected for these impurities, thus, the actual quantity of zirconium
could be up to 2 percent less than that listed. A considerable
deposit of insoluble material remained when the zirconium tetrachloride
was mixed with the water; therefore, the supernatant was carefully
pipetted from the stock solution to avoid contamination with
the undissolved solids. Lanthanum rare-earth chloride (LaRECl)
was added as the complete compound and data represent mg/1 of the entire
compound. Actual lanthanum content of the LaRECl was about 23.5
percent.
One day after neutralization five 24-hour-old (± 12 hours) Daphnia
magna were added to each beaker, and the beakers placed in environmental
chambers at 18° ± 2°C. Light, provided by cool white fluorescent
bulbs at an intensity of approximately 2150 lux, was cycled on
a 16-hour light and 8-hour dark photoperiod. Surviving organisms
were enumerated every 24 hours until the 96-hour test was completed,
and the results used in the calculation of the 96-hour TL . Three
m
separate tests v/ere conducted on each inactivant. During each test,
four replicates were run for each inactivant addition, making
a total of twelve replicates for each concentration of a given
inactivant material.
47
-------
9-Week Three-generation Tests
Cladocera -
The rearing methodology and general experimental procedure were
the same as for the 96-hour tests, but the counting procedure
differed. Counts were made at weekly intervals, at which time
the surviving adults (parental generation) were transferred to new
water-inactivant mixtures. The young were counted and discarded.
At the end of week 3 the adults were discarded and five of the
youngest offspring (F. generation) were transferred to fresh
water-inactivant mixtures. Counts and transfers were conducted
for the following 3 weeks in the manner described for the original
test organisms. At the end of week 6, the adults were again
discarded and five of the youngest offspring (F~ generation)
transferred to fresh water-inactivant mixtures. Counts and
transfers were made as previously described. Three different
generations were thereby examined: the original (parental)
generation which was never exposed to the inactivant before birth, one
generation (F-,) whose parents were exposed after birth and who
themselves were exposed to the inactivant for all phases of their
life cycle, and one generation (F?) whose parents as well as
themselves were exposed to the inactivant throughout all phases
of their life cycle. Replication was the same as in the 96-hour
tests.
Graphic determinations of 1-week TL values were made and reproductive
rates per individual were calculated. The reproductive rate per
individual was estimated by dividing the total number of young
surviving at the end of the one-week interval by the mean of the
adults existing at the beginning and at the end of the week.
48
-------
Tests With Benthic Organisms
The benthic test organism is a midge, originally classified
as Tanytarsus dissimilus (Johannsen). Its exact taxonomic status
is presently in doubt. Professor J. E. Sublette, Eastern New
Mexico University, (personal communication) considers it a form
of Paratanytarsus. The organism is ideal for stress studies
because of its extreme sensitivity to toxicants (Nebeker and
Puglisi , Nebeker , Bell1 ), and its parthenogenetic mode
of reproduction. We have maintained cultures in one-gallon
soft-glass jars for over six months and the organisms have continued
to reproduce at the expected frequency. They are fed, twice
weekly, with the same food used for the Daphnia. Water levels
are maintained by addition of glass-double-distilled water.
Tests using this organism have not yet been conducted, but they
will be designed to measure survival through all stages of the
aquatic life cycle. The egg masses will be collected from the adults
and placed in petri dishes to hatch. Five first instar larvae
will be removed, placed in beakers, and incubated for approximately
18 days at 22°C, the approximate time necessary for the midge to
complete its aquatic life cycle. The number of cast pupal skins
found on the water surface after adult emergence will be used to
calculate the TL values.
Chemical Data
Alkalinity, hardness and dissolved solids were determined at the
beginning of each study. Average values for each pair of duplicated
containers appear in Table 13, which lists all the tests that were carried
49
-------
Table 13. Chemical Composition of Hater Used 1n Toxlclty Tests
Inactlvant Organism
Sodium Aluminate Chinook Salmon
Sodium Aluminate Daphnia
Zirconium Refinery Waste Coho Salmon
Zirconium Refinery Waste Daphnia
Zirconium Tetrachloride Coho Salmon
Zirconium Tetrachloride Daphnia
Zirconium Tetrachloride Daphnia
(Week 1)
Zirconium Tetrachloride Daphnia
(Week 2)
Zirconium Tetrachloride Daphnia
(Week 3)
Zirconium Tetrachloride Daphnia
(Week 4)
Inactivant
Concentration
rag/1
0.0 (Control)
0.0 (Control)
0.0 (Control)
1.0
5.0
10.0
15.0
0.0 (Control)
0.5
1.0
6.7
10.0
0.0 (Control)
0.5
1.0
5.0
10.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
Alkalinity
mg/1
25.0
27.0
28.0
45.3
104.8
220.5
398.0
34.0
28.0
27.0
28.0
27.5
25.7
22.7
23.0
20.0
26.3
30.0
28.0
26.0
24.0
21.0
25.0
23.0
18.0
6.0
2.0
25.0
23.0
19.0
10.0
4.0
27.0
31.0
23.0
2.0
2.0
Hardness
mg/1
28.0
27.0
29.0
69.8
165.5
279.3
420.0
38.0
37.5
37.0
38.5
36.0
28.0
27.7
28.0
29.7
26.7
28.0
30.0
28.0
27.0
25.0
34.0
24.0
30.0
32.0
26.0
29.0
27.0
30.0
27.0
28.0
32.0
28.0
32.0
30.0
Dissolved
Solids
mg/1
69.0
67.8
139.5
268.5
426.3
536.3
92.0
98.0
89.0
100.0
81.0
77.0
81.3
76.7
121.0
99.7
70.0
73.0
77.0
84.0
118.0
73.0
74.0
81.0
91.0
110.0
78.0
77.0
72.0
96.0
103.0
81.0
70.0
80.0
99.0
124.0
50
-------
Table 13. (Continued)
Inactlvant
Zirconium Tetrachloride
(Meek 5)
Zirconium Tetrachloride
(Week 6)
Zirconium Tetrachloride
(Week 7)
Zirconium Tetrachloride
(Week 8)
Zirconium Tetrachloride
(Week 9)
Lanthanum Rare Earth
Chloride
Lanthanum Rare Earth
Chloride
Zlrconyl Chloride
Organism
Daphnia
Daphnia
Daphni a
Daphnia
Daphnia
Coho Salmon
Daphnia
Daphnia
Inactivant
Concentration Alkalinity
mg/1 rag/1
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
1.0
5.0
10.0
20.0
0.0 (Control)
0.5
1.0
2.0
5.0
0.0 (Control)
1.0
5.0
10.0
20.0
27.0
27.0
19.0
11.0
4.0
30.0
29.0
20.0
12.0
7.5
32.0
22.0
18.0
2.0
2.0
28.0
26.0
22.0
20.0
16.0
30.0
24.0
21.0
20.0
32.0
29.5
27.5
28.0
27.0
28.0
28.0
28.0
27.7
28.3
30.0
31.7
31.3
32.0
34.0
Hardness
mg/1
28.0
29.0
28.0
28.0
25.0
26.0
28.0
24.0
25.0
26.0
30.0
32.0
29.0
25.0
26.0
28.0
30.0
28.0
28.0
28.0
33.0
36.0
34.0
35.0
42.0
25.0
35.5
35.5
36.0
36.0
29.0
29.3
29.3
28.7
29.7
32.7
32.7
32.0
31.7
30.7
Dissolved
Sol Ids
mg/1
67.0
67.0
70.0
74.0
98.0
79.0
76.0
83.0
92.0
103.0
78.0
76.0
80.0
85.0
108.0
71.0
73.0
79.0
88.0
118.0
63.0
90.0
70.0
77.0
103.0
89.0
93.0
96.0
96.0
110.0
79.7
84.3
86.0
89.3
107.0
77.3
73.3
105.3
98.7
114.3
51
-------
out. In tests using sodium aluminate the soluble aluminum fraction
was measured at the beginning of the tests; those results are given
in the sections dealing with the aluminum bioassays.
Experimental Difficulties
The floe, in some instances, acted as a physical barrier to movement
for the Daphnia. In higher concentrations, particularly with sodium
aluminate, they could be seen trailing strings of floe from their
caudal spine. It was necessary to feed the organisms because of
the test duration, which may have resulted in reduced toxicity.
52
-------
RESULTS
Sodium Aluminate
Fish -
Chinook salmon (12-15 cm) were used to test sodium aluminate
in concentrations of 0.0 (Control), 5.0, 10.0, 20.0, and 40.0 mg Al/1
These values represent the amount added (as aluminum), not the
amount of particulate or soluble aluminum remaining in solution
after the precipitation reaction. Table 14 gives actual soluble
aluminum concentrations. The erratic distribution of values can
not be explained adequately, but probably lies within the limits
of error of the analysis.
Table 14
Dissolved Aluminum Concentrations, Sodium Aluminate
Fish Bioassay
Added Aluminum Dissolved
Aluminum Concentration Aluminum
Concentration at 0 hours Concentration
at 96 hours
(mg/1) (mg/1)
0.0 (Control)
5.0
1C.O
20.0
40.0
<0.02
0.03
0.07
0.04
<0.02
<0.02
<0.02
0.05
<0.02
<0.02
53
-------
All fish survived the 96-hour test period. Only five fish were
tested at the 40 mg/1 concentration because of a shortage of fish,
and only nine at 10 mg/1 because of an initial miscount. The test
was allowed to continue for 216 hours. One fish whose caudal fin
had been chewed by the others died in the 40 mg/1 concentration
at 120 hours; all the others survived.
Cladocera: 96 Hours -
Sodium aluminate was relatively non-toxic to D. magna. Somewhat
higher mortalities were observed in the higher concentration levels
but at no time was a 96-hour TL reached. Experimental concentrations
of 0.0 (Control), 5.0, 10.0, 20.0, and 40.0 mg Al/1 were used in
the bioassay. The average soluble aluminum values for these tests
are given in Table 15. A graphic presentation of the percentage
survival is shown in Figure 9.
Table 15
Aluminum Concentrations, Sodium Aluminate Daphm'a magna Bioassay
Added Dissolved
Aluminum Aluminum
Concentration Concentration
(mg/1) at 96 hours
(mg/1)
0.0 (Control)
5.0
10.0
20.0
40.0
0.045
0.055
0.045
0.040
0.080
54
-------
40.CH
",20.oH
o
!5
IT
IO.OH
o
o
5.CH
1.0
O 24 HOURS
O 48 HOURS
Q 72 HOURS
A 96 HOURS
A EE>O
0 10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 9. Percent survival of Daphnia magna in four concentrations
of sodium aluminate over 96 hours
-------
Zirconium Refinery Waste
Fish -
Coho salmon of similar size were used in the zirconium refinery
waste toxicity tests (Table 16). Quantities added were 0.0 (Control),
1.0, 5.0, 10.0, and 15.0 grams of waste per liter. A highly turbid
condition resulted upon addition of the waste material, sufficient
to prevent visual observation of the fish during the early stages
of the test. At the end of 96 hours most of the material had
settled. All fish survived the 96-hour test and a continuation
to 192 hours.
Table 16
Average Length/Weight Measurements of Coho Salmon at Termination of
96-Hour Zirconium Refinery Waste Bioassay
Refinery Waste
Added
9/1
0.0 (Control A)
0.0 (Control B)
1.0 A
1.0 B
5.0 A
5.0 B
10.0 A
10.0 B
15.0 A
15.0 B
Avg. Length
(cm)
14.2
14.1
14.0
14.0
13.9
14.3
14.0
14.4
14.3
13.7
Avg. Wt.
(g)
24.4
21.1
21.9
21.9
21.9
23.6
22.1
23.1
21.8
21.0
56
-------
Cladocera -
The zirconium refinery waste was also tested with D. magna.
The dry weight of material added was 0.0 (Control), 1.0, 5.0,
10.0, and 15.0 g/1. As with the fish, the experimental solutions
were very turbid after the material was added; however, after
24 hours clarty was sufficient to permit enumeration. Observed
mortalities reached 15% of the total population (Figure 10).
Zirconium Tetrachloride
Fish -
Zirconium tetrachloride was tested with coho salmon from the same group
used for zirconium refinery waste. The concentrations tested were 0.0
(Control), 0.5, 1.0, 6.7, and 10.0 mg Zr/1.
All fish survived the 96-hour test. The tests were then continued
to 240 hours during which time two fish died, a control at 120 hours and
one in the 1.0 mg Zr/1 solution at 192 hours. The remaining fish still
survived when the test ended at 240 hours. Table 17 lists the average
length and weight measurements at the termination.
Table 17
Average Length/Weight Measurements of Coho Salmon at Termination
of 96-Hour Zirconium Tetrachloride Bioassay
Zirconium Concentration
(mg/1 )
0.0
0.0
0.5
1.0
1.0
1.0
6.7
6.7
10.0
10.0
Avg. Length
(cm)
12.5
12.7
13.4
13.0
12.3
12.4
14.2
12.2
13.4
13.7
Avg. Wgt.
(g)
16.5
20.0
22.4
21.0
17.6
19.3
27.7
17.4
22.9
22.3
57
-------
z
o
tr
LU
o
o 15.0-
o
LJ
I-
< 10.0'
oc
Ld
z
5.0-
o
O
^
MJ
1.0
O 24 HOURS
048 HOURS
Q 72 HOURS
A 96 HOURS
-BS-
0 10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 10. Percent survival of Daphnia magna in four concentrations
of zirconium refinery waste over 96 hours.
-------
Cladrocera: 96 Hours -
Crude zirconium tetrachloride was relatively non-toxic to D. magna
at the concentrations tested: 0.0 (Control), 1.0, 5.0, 10.0, and 20.0
mg Zr/1. A 96-hour TL was not reached within this range. Higher
mortalities were noted in the 10.0 and 20.0 mg/1 concentrations;
the maximum number of deaths represented 22% of the original
population (Figure 11).
Cladocera: 9 Weeks -
Crude zirconium tetrachloride was also subjected to the 9-week test.
The concentrations were: 0.0 (Control), 5.0, 10.0, and 20.0 mg Zr/1.
A 7-day TL was not found during either the first or second week.
At the end of week 3, a TL of 2.0 mg Zr/1 had been reached (Figure 12).
Following the first three-week test period, five of the smallest (or
the total surviving if less than five) offspring in each beaker
were transferred to another beaker containing the same concentration
of zirconium, and the test carried out for another three weeks.
The week 4 animals (comparable in age structure to the week 1 individuals
of the initial three-week run) exhibited a TL of 20.0 mg Zr/1.
m
The week 5 organisms (comparable in age to the second-week organisms)
had a TL of 11.5 mg Zr/1 and the week 6 (comparable in age to week
3), 1.1 mg Zr/1 (Figure 13).
The transfer procedure was repeated at the end of week 6. The TL
m
for week 7 organisms, of a comparable age to those in weeks 1 and 4,
decreased to 18.5 mg Zr/1. A week 8 TL was observed at two
points--!6.0 end 4.4 mg Zr/1. The week 9 TL was 1.8 mg Zr/1
(Figure 14).
Reproductive rate per individual per week was also calculated for
the nine-week test. Figure 15 indicates that, in general, the
higher the concentration the fewer young produced.
59
-------
o
<
cr
o 10.0
o
o
o
o
tr
ru
5.0-
1.0
O 24 HOURS
O48 HOURS
Q72 HOURS
A 96 HOURS
A Q <3©
0 10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 11. Percent survival of Daphnia magna in four concentrations
of zirconium tetrachloride over 96 hours.
-------
o
"20.0-
QL
I-
10.0-
o
o
8
1.0
CD
CD
0 I WEEK
O 2 WEEK
Q 3 WEEK
0
0
O
O O
3 WEEK TLM=2.0 MG. ZR/L
0 10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 12. Percent survival of Daphnia magna in three concentrations of
zirconium tetrachloride during weeks 1-3 of 9-week toxicity test.
-------
--20.0-
o
or
H-
o 10.0
o
o
8 5-OH
a:
1.0
5 WEEKTLM=II.5MG ZR/L
_J
O 4 WEEK
0 5 WEEK
0 6 WEEK
4 WEEK TLM= 20.0 MG ZR/L
0
O
6 WEEK TLM=I.I MG ZR/L
0 10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 13. Percent survival of Daphnia magna in three concentrations of
zirconium tetrachloride during weeks 4-6 of 9-week toxicity test,
-------
o
. 20.0 -I
g
<
or
10.0
z
o
o
8
1.0
8 WEEK TLM= 16.0 MG
9WEEKTLM=I.75 MG ZR/L
Q 7 WEEK
O 8 WEEK
9 WEEK
7 WEEK TLM= 185 MG ZR/L
O
8 WEEK TLM=4.4 MG ZR/L
10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 14. Percent survival of Daphm'a magna in three concentrations of
zirconium tetrachloride during weeks 7-9 of 9-week toxicity test,
-------
LU
CL
o
I
u_
o
o:
UJ
00
CONTROL
O I MG ZR/L
O 5 MG ZR/L
E 10 MG ZR/L
A 20 MG ZR/L
WEEK
Figure 15. Daphnia magna reproductive rate per individual per week during
9-week zirconium tetrachloride toxicity test.
-------
,-20.0-
a:
h-
o IO.O-
o
o
o
o
tr
ru
5.0-
1.0
O 24 HOURS
O48 HOURS
Q72 HOURS
A 96 HOURS
A 0
0 10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 16. Percent survival of Daphnia ma^na, in four concentrations
of zirconyl chloride over 96 hours.
-------
o
!5
LU
o
o
o
LJ
O
o:
o
_j
X
0
Z)
<
20.0
10.0
X
h-
C£
UJ
LU
o:
O 24 HOURS
O 48 HOURS
Q 72 HOURS
A 96 HOURS
WIG LA/L
Figure 17.
30 40 50 60 70 80
PERCENT SURVIVAL
Percent survival of coho salmon in four concentrations
of lanthanum rare earth chloride over 96 hours.
-------
Zirconyl Chloride
Fish -
No tests were carried out on fish.
Cladocera -
Zirconyl chloride (ZrOCl2) was tested at 0.0, 1.0, 5.0, 10.0, and
20.0 mg Zr/1. The results were similar to those obtained with
zirconium tetrachloride, with excellent survival at all concentrations.
Maximum mortality was 17%, occurring at the 96 hours, 20 mg Zr/1 level
(Figure 16).
Lanthanum Rare-Earth Chloride
Fish -
A lanthanum rare earth chloride was tested in the same manner as
the previous substances, using coho salmon. The concentrations
used were: 0.0 (Control), 1.0, 5.0, 10.0, and 20.0 mg La rare earth
chloride mixture/1. All fish exposed to concentrations greater than 1.0
mg/1 died within the first 24 hours (Figure 17). The TL for 24
hours was approximately 2.0 mg/1. The control and 1 mg/1 organisms
survived to 240 hours with the loss of only one fish. Average
length and weight measurements at the termination of the test are
listed in Table 18.
67
-------
Table 18
Average Length/Weight Measurements of Coho Salmon at Termination of
96-Hour Lanthanum Rare Earth Chloride Bioassay
Lanthanum Rare Earth Chloride
Concentration
(mg/l )
0.0
0.0
1.0
1.0
5.0
5.0
10.0
10.0
20.0
20.0
Avg. Length
(cm)
13.7
13.2
13.4
12.9
14.3
14.5
13.7
14.5
14.0
14.0
Avg. Weight
(g)
20.1
16.1
17.4
15.1
24.5
26.1
23.1
23.9
24.8
23.4
Cladocera -
Rare earth lanthanum chloride proved to be more toxic than the
other substances. Because of the high mortality of fish, Daphnia
were examined at decreased inactivant concentrations to include
0.0 (Control), 0.5, 1.0, 2.0, and 5.0 mg La rare earth chloride
mixture/1. A 72-hour TL of 2.81 mg/1 and a 96-hour TL of 1.61
m y m
mg rare earth lanthanum chloride were obtained (Figure 18).
68
-------
o 5.0-
cc
o 2.0
o
o
LU
cr
3
O
<
X
I
J-
(T.
UJ
UJ
o:
cr
1.0-
0.5-
O.I
G 24 HOURS
O48 HOURS
Q 72 HOURS
A 96 HOURS
O
O
72 HOURS TLM = 2.8 MG LA/L
O
96HOURS TLM = I.6 MG LA/L
0 10 20 30 40 50 60 70 80 90 100
PERCENT SURVIVAL
Figure 18. Percent survival of Daphm'a magna in four concentrations
of lanthanum rare earth chloride for over 96 hours.
-------
DISCUSSION
The foregoing tests were designed to determine whether substances being
screened as possible nutrient inactivants could be expected to be
harmful to aquatic organisms over anticipated ranges of operational
concentrations. Results should not be interpreted as criteria
for discharge levels or water quality standards.
The results of the toxicity tests should be interpreted in a general
manner. As previously stated, they were designed specifically to
test the inactivant under laboratory conditions and the relation
of these results to actual field conditions is unknown. In those
cases where a gradual increase in toxicity occurs with increasing
inactivant concentration, as demonstrated by zirconium and aluminum,
a workable concentration range could probably be established. However,
the results with highly toxic materials, as seen with the lanthanum
rare earth chloride, suggests the use of extreme caution even though
loss of biota might be considered non-critical to the project.
Potable water supplies for humans and animals could be involved.
The importance of toxicity in relation to field conditions is
likely to be variable. Under some conditions a massive reduction
in the native biota may be tolerable if the toxicity is of short
duration. Heavy application of an inactivant could in some cases result
in a blanketing of the sediment water interfaces. The composition
of this substance might prevent recolonization by benthic populations
and thus lead to a significant reduction in the consumer population
with an overall shift in the structure of the ecosystem. The use to
70
-------
which a particular aquatic environment is to be put becomes an
important factor in determining if, and what type of nutrient in-
activation will be used. The loss of a critical nutrient (the primary
focus of the inactivation treatment) will in itself cause a reduction
in the consumer population through reduction of the available
food supply. Thus, if it is sought to achieve conditions where
nuisance algal growth is limited but a productive fishery is
maintained, toxicity of an inactivant will likely become a critical
consideration. If the desire is to create a quasi-oligotrophic
system, however, a short term toxicity may be tolerable providing
the treatment does not prevent recolonization by aquatic organisms
for an extended period of time.
The introduction of materials with cumulative effects must be
avoided. Such materials would damage not only the aquatic population
but might eventually be cycled to humans. Therefore, the utmost
precaution, involving thorough testing of inactivants, must preceed
their general use.
Following is a brief resume of the data available on the toxicity
of various compounds tested during the present study. Our results
are compared to those from the literature where possible to determine
if the operational inactivant levels established by our experiments
are compatible with non-toxic levels of the material as reported
by others.
Alumi num
1R
Everhart and Freeman found (1) debilitation of rainbow trout
after one week's exposure to the addition of 5.2 nig/1 aluminum
at any pH examined; (2) acute mortalities at 5.2 mg/1 dissolved
aluminum, while mortality rates were more chronic with equivalent
71
-------
suspended amounts (chronic being defined as a long-termed debilitation
without lethality); (3) toxic effects were lower for suspended
aluminum than dissolved aluminum, and (4) physiological damage
incurred by young fish appeared to be reversible in the survivors.
They also found the fish were able to tolerate 0.05 mg/1 dissolved
aluminum, with normal-appearing growth and behavior. This concentration
represents the saturation point at pH 7.0 and will remain in solution
at all higher pH levels.
19
Anderson found aluminum chloride toxic to Daphnia magna at 6.7
20
mg/1 in Lake Erie water. Pulley , on the other hand, found no
toxicity to small marine invertebrates and adult fish from 44 mg/1
of aluminum chloride at a pH range of approximately 5.2 - 6.8.
21
Water Quality Criteria lists various aluminum salts which have been
found to be toxic to fish and other aquatic life. Aluminum nitrate
at 0.10 mg/1 was lethal to sticklebacks exposed for one week; 0.30
mg/1 was lethal after an exposure of only one day. Aluminum chloride
at 0.27 mg/1 was lethal to eels by 50 hours, and 2.7 mg/1 was lethal
22
by 3.6 hours. Biesinger and Christensen established an LD5g of
1.40 mg Al/1 for Daphnia magna in Lake Superior water over a
three-week period (pH range 6.5 - 7.5) at a concentration of 5 mg
Al/1.
Our tests indicated that sodium aluminate adjusted to pH 7.0 ± 0.2
at the beginning of the test was not lethal to fifty percent of the
organisms tested, either chinook salmon or cladocera. A maximum
of 35% of the Daphnia died after 96 hours at approximately 40 mg
Al/1. The actual concentration of dissolved aluminum ranged from
0.06 to 0.02 mg/1. This appears to be within the range of Everhart
18
and Freeman who found 0.05 mg Al/1 to be relatively non-toxic to
72
-------
rainbow trout. The results of our chinook salmon test were also
within that ranges varying from 0.02 to 0.07 mg Al/1. Gahler
and Sanville (unpublished), in a pilot field study, found no
deleterious effects to resident rainbow trout when a neutralized
aluminum hydroxide slurry was applied to a pond at 10 rng Al/1. Aluminum
has been applied to several lakes by the Inland Lake Renewal and
23
Management Demonstration Project, Upper Great Lakes Regional Commission
and they, too, have reported no serious disruptions of the food
chain or evidence of direct toxicity.
Zirconium
Zirconium has been reported as relatively inert with respect to
24
biological systems. Cochran, et. al., found that 800 to 1600
mg of zirconium per kilogram of body weight was necessary to
demonstrate acute toxicity when administered orally to rats. This
included the acetate, chloride, nitrate and sulfate salts. Palange,
25
et. al., reported 48-hour TLm values of 14.4 and 17.8 mg/1,
respectively, for zirconium sulfate and zirconyl chloride to fathead
pc
minnows in soft water. Tarzwell and Henderson found a 96-hour
TL for the fathead minnow of 14 mg Zr/1 in soft water and 115
mg/1 in hard water. Zirconyl chloride exhibited 96-hour TL values
of 18 and 240 mg Zr/1, for soft and hard water, respectively. The
27
actual dissolved concentrations were not reported. Collier has
reported zirconium concentrations of 0.34 - 3.4 mg Zr/1 during a
bloom of Gymnodinium off the coast of Florida.
The results of our study indicate that for a 96-hour test the zirconium
was not extremely toxic to either coho salmon or Daphnia^. In general,
the fish were affected less. All fish survived the 96-hour test period
and a 96-hour TLm was not observed in the Daphm'a study. As pointed
out, the concentrations of soluble zirconium were not determined and
the material used was known to contain some impurities. Observed
mortalities could have been the result of contaminants.
73
-------
in general, heavy metal toxicity is greater in soft water than
hard. The water used in our tests had relatively low hardness levels of
30-40 mg/1 which might amplify the toxic effects of elements in our tests.
Harder water environments could possibly reduce toxicity.
The 9-week-three generation test was designed to explore chronic effects
of exposing DA magna to zirconium tetrachloride. Two facets
were examined, (1) effect on adult survival, and (2) effect on reproduction,
The test was designed so that all young used after the initial
introduction were exposed to the zirconium for their entire life
cycle. One might expect a natural selection in which more resistant
Daphnia are used as new assay animals. The expected result of this
would be lower mortality and higher reproductive rates during the
second and third phase of the study. However, mortalities and
reproductive rates did not indicate occurrence of selective processes
during the bioassay.
The test results generally showed a gradual increase in sensitivity
to crude zirconium tetrachloride with time. TL values for weeks
m
1 through 9 were shown in Figures 12, 13, and 14. In interpreting the
graphs, it must be remembered that weeks 4 and 7 represent young
transferred from previous tests. Week 1 individuals had never been
exposed previously to the inactivant, week 4 individuals were offspring
of adults which had been exposed for three weeks, and week 7 individuals
were offspring of adults whose parents had been exposed for three
weeks as adults and up to three weeks as immature organisms. Week
2, 5, and 8 individuals were approximately one week old and by the
end of the week had been exposed to the inactivant as adults for two
weeks. Week 3, 6, and 9 individuals were all of the same age
structure and by the end of the week had been exposed to the
inactivant as adults for 3 weeks. Therefore, in assessing the
74
-------
week to week effects of exposure, one must compare weeks 1, 4, and 7;
2,5, and 8; and 3, 6, and 9. The TL value for week 1 (Figure
4) was above tie concentrations tested, i.e., survival at all concentrations
was >50%. The Tt_m was 20.0 mg/1 for week 4, and for week 7 it was
18.5. The sams trend was seen in weeks 2-5-8. There was no indicated
TLm for week 2, but for week 5 a Tl_m of 11.5 was found. Two TLm
values were indicated for week 8; the higher (16.0) is probably
in error, since the lower value of 4.4 is nearer the expected level.
The lowest TL values were found in weeks 3, 6, and 9, and probably
represent the maximum stress the animals can tolerate independent
of previous exposure to the test material.
Data on effects of exposure on reproduction (Figure 7) indicate
a decreased number of young produced with each succeeding increase
in concentration until a maximum level of reproductive impairment
is reached. It appears that this level is reached between 5.0 and
10.0 mg Zr/1 after which higher concentrations have little effect.
At 10.0 and 2C.O mg Zr/1 reproductive impairment appeared to be
.
comparable after the fourth week, with the exception of an erratic
peak for 20.0 mg/1 at week 6. It must be borne in mind, however,
that at the higher inactivant concentrations the number of surviving
adults is so low that a single tolerant adult which produced a large
number of young could sufficiently increase the reproductive rate
per individual to signficantly bias the result.
Lanthanum
Lanthanum has been reported as relatively non-toxic. Cochran et al
found LD5Q va" ues of 4,200 rag LaC"^ per kilogram body weight for
rats to which lanthanum chloride had been administered orally.
He concluded that the LDr value was directly related to absorption
75
-------
of the ingested compounds and that lanthanum ammonium nitrate was
the most soluble and the most toxic of the administered lanthanum
compounds. Interperitoneal LD,-n levels were much lower. Kyker
o o OU
and Cress reported LD5 values for interperitoneal injections
of lanthanum considerably lower than those of Cochran, but did
OQ
not experiment with oral dosage. Bringmann and Kuhn found a
median threshold effect for Daphnia of 160 mg La/1 after 48 hours
and 0.15 mg La/1 for Scenedesmus after four days.
Our results with lanthanum rare earth chloride showed an extreme
toxicity to coho salmon and a relatively high toxicity to ID. magna
tested at lower inactivant concentrations. All fish exposed to
concentrations greater than 1 mg lanthanum rare earth chloride/1
died within the first 24 hours and a 96-hour TL of 1.6 was observed
m
with Daphnia.
76
-------
VII. STABILITY AND DURATION OF EFFECTIVENESS
OBJECTIVES AND APPROACH
One of the most important aspects of the nutrient inactivation
concept is the stability of the effect. Whereas this problem
is not critical in the treatment of municipal water supplies or
wastes, where conditions can be carefully manipulated, reaction
times are short, and preciptants are removed, in natural waters it
may be affected by a number of uncontrollable variables such as
temperature, pH, oxygen level, etc. It is particularly important
to determine the behavior of inactivants in aerobic and anaerobic
systems when considering the interaction between iriactivant-
phosphorus complexes and sediment and whether such complexes
will affect the release of phosphorus from the sediment.
The problem has been approached here by developing experimental
laboratory setups in which natural, undisturbed sediment-water
systems are approximated. Using these systems as laboratory
microcosms, inactivant materials are added to the water following
32 33
the addition of P. A second isotope tracer, P, is then added
to the sediment. Through use of the dual tracer system, the effect
of precipitated inactivant-phosphorus complexes on release of
exchangable phosphorus from the sediment, and the rate of release
of phosphorus from the inactivant complex are expected to be
determined.
DEVELOPMENT OF QUANTITATIVE METHODS
Sampling
A Jenkin coring apparatus30 was used to obtain sediment-water
samples from Cline's Pond for the laboratory studies. Experience
77
-------
with this device has shown that essentially undisturbed samples
can be obtained, to the extent that midge larvae tubes are
maintained intact on the surface of the sediment. Initially
the plastic coring tubes were fitted with glass liners to minimize
phosphorus adsorption. All of our studies to date have used the
glass-lined coring tubes; however, we have since found that there
is no signficant difference in phosphorus adsorption on the
glass liners and the acrylic plastic coring tubes themselves.
Plastic tubes will be used in future studies. A series of sampling
ports were bored in each column and filled with silicone rubber
(Figure 19), allowing the sample collector to serve as the laboratory
experimental vessel, and precluding the need for transferring
and disturbing the sample.
Height of sediment in the coring tubes is dependent on the texture
and compactness of the substrate being sampled and thus varies
somewhat from tube to tube. Following collection, therefore,
sediment levels are adjusted to approximately 1 cm above the
lowest sampling port. Excess sediment is "drained off" by removing
the seal on top of the core and gently rocking the bottom seal
from side to side, allowing sediment to seep out the bottom.
This manipulation does not significantly disturb the mud-water
interface. The water level is then restored by adding water
from a reserve supply obtained from just above the lake bottom
at the time of sample collection.
Establishment of Aerobic and Anaerobic Systems
Aerobic and anaerobic columns are subjected to the same standard
conditions except for the type of gas (air or nitrogen) supplied.
78
-------
GLASS LINER
EXIGLAS CORING TUBE
CORING TUBE HARNESS
SPRING
SILICONE RUBBER FILLED
SAMPLING AND INJECTION
PORTS
PLEXIGLAS "0" RINGS BETWEEN
PLASTIC AND GLASS
Figure ~\9. Jenkin corer tubes modified for laboratory experiments.
-------
It has been necessary to establish the minimum identical air and
nitrogen inputs to the columns required to ensure that one set
remains aerobic and the other anaerobic, while at the same time
water circulation is held to a minimum. A distribution manifold
with gas flow regulators proved unsatisfactory and was replaced
with a 15-channel Technicon peristaltic pump which meters equal
gas flows to duplicate pairs of aerobic and anaerobic sealed columns.
An underwater bleed-off prevents air from leaking back into the
columns (Figure 20) and maintains equal pressure on all columns.
Gas pumping rates of 0.10, 0.25, 0.80, and 1.60 cc/min were tested
to determine the minimum acceptable gas flow. It was determined
that a rate of 0.25 cc/min produced the desired aerobic and anaerobic
conditions with a minimum of turbulence (Table 19).
Low concentrations of oxygen were initially present in the nitrogen
purged columns (0.4 - 0.8 mg/1). Our nitrogen source was a pre-
purified gas containing a claimed concentration of < 5mg/l oxygen.
An "oxy-trap" (Attech Associates) was installed in the line between
the nitrogen cyclinder and the Technicon pump, reducing oxygen levels
in the columns to a range of 0 - 0.2 mg/1. This was considered
operationally anaerobic.
80
-------
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Table 19
Nitrogen-Air Pumping Rates to Experimental
Columns as Related to Dissolved Oxygen Levels
Pumping Rate Gas
cc/min
1.60 N2
1.60 Air
0.8C N2
0.80 Air
0.25 N2
0.25 Air
0.10 N2
0.10 Air
Day 1
0
10+
0
10+
0
10+
1.5
9.2
Dissolved Oxygi
mg/1
Day 2
0
9.4
0
8.0
0.2
8.0
1.6
7.2
82
-------
Subsampling and Analytical Techniques
The glass lined Jenkin coring tubes have an approximate volume
2
of 1300 ml and a cross-sectional area of 23.8 cm . The
relatively smell water volume and the frequent analyses required
by these experiments necessitates the use of very small sample
volumes and micro-analytical techniques. Micro-techniques have
been used by other investigators for some of the parameters we
wished to measure, but for most, our own techniques had to be
developed.
Phosphorus -
The method usually employed for phosphorus determination in our
laboratory is that given in "Methods for Chemical Analysis for
Q
Water and Was-ses, 1971" . This method, which is a modification
of the Murphy and Riley single solution method, requires a
50 ml sample size. Our plan was to proportionately scale-down
all of the reagent volumes to suit our 2.5 ml sample size.
Results using this procedure were poor: replicates gave 25 to
100 percent error. Although contamination of the samples was
magnified because of their small volume, lack of precise acidity
and temperature control appeared to produce the greatest variation.
This method was ultimately abandoned in favor of an EPA automated
0
method where acidity and temperature variation could be eliminated.
The automated method, however, also produced poor replicates,
until it was discovered that acid-washed plastic syringes used
to load samples into the specially adapted 5 ml containers used
by the automated system were an apparent source of contamination.
83
-------
Initially the syringes were acid-washed, rinsed in distilled water,
dried in a circulating air oven, and stored under cover until the
next use. Acceptable replication was not obtained until the syringes
were allowed to soak in 1:1 HC1 during storage and rinsed with distilled
water immediately before use. Following this modification, the
automated procedure utilizing 2.5 ml sample volumes and acid-soaked,
distilled water-washed plastic syringes was consistently reliable
and reproducible (see Figure 21 and Table 20). Differences between
20 sets of replicates with phosphorus concentrations ranging from
0.005 to 1.61 mg/1 was 0.01 - 0.02 mg/1. The mean variation between
20 sets of replicate samples (both standards and pond water) was
0.008 mg/1 phosphorus.
Oxygen -
Several micro and semimicro oxygen techniques were considered for
use in our experiments and discarded for various reasons. A method
32
described by Carpenter required a 125 ml sample, much larger than
DO
we could use. A polarographic technique described by Koch and Kruuv
was rejected for the same reason. A microprobe used for the determination
of oxygen levels in microbial slime films was considered (Bungay
et. al.34, Sanders et. al.35, and Whalen et. al.36), but it was
decided that sulfides in our experimental columns might rapidly
poison the 1.5 p diameter microprobe.
An apparatus similar to that used by Whitney was then assembled
and tested. The technique was essentially a micro-Winkler system
requiring a 10 ml sample. The sample was collected in a syringe
which also served as the titration vessel, thereby eliminating prolonged
exposure to air. However, the short exposure time when the syringe
needle was removed and the titration burette needle reinserted was
apparently sufficient to allow atmospheric contamination.
84
-------
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Table 20. Results of Replicate Sample Tests for Total Phosphorus Using the
Autoanalyzer with 2.5 ml Samples (Base = 0.50, C/A - 0.333).
Replicate
Sample
Number
STANDARDS
1
2
3
4
5
6
7
8
9
10
11
CLINE'S POND
12
13
14
15
16
17
18
19
20
Peak
Height
0.52
0.52
0.53
0.53
0.50
0.51
0.50
0.54
0.54
0.52
0.52
0.57
0.57
0.61
0.57
0.83
0.82
1.70
1.74
1.60
1.66
WATER
3.74
3.77
3.66
3.69
3.91
3.92
4.01
4.04
4.37
4.34
4.69
4.67
4.96
5.03
5.29
5.32
5.11
5.09
Mean Variation =
Percent
Variation in
Peak Height
Between
Replicates
0.0
0.0
2.0
4.0
0.0
0.0
0.0
6.6
2.7
2.3
3.6
0.7
0.8
0.2
0.7
0.7
0.4
1.4
0.6
0.4
1.4
Calculated
Phosphorus
Concentration
mg/1
0.000
0.000
0.000
0.000
0.005
0.005
0.020
0.020
0.100
0.400
0.400
Measured
Phosphorus
Concentration*
mg/1
0.007
0.007
0.009
0.009
0.000
0.006
0.000
0.010
0.010
0.006
0.006
0.020
0.020
0.040
0.020
0.110
0.110
0.400
0.410
0.370
0.390
1.08
.09
.05
.06
.14
.14
.17
1.18
1.29
1.28
1.40
1.39
1.49
1.51
1.60
1.61
1.54
1.53
Difference
Between Measured
Phosphorus
Concentrations
of Replicates
mg/1
0.000
0.000
0.010
0.020
0.000
0.000
0.000
0.020
0.000
0.010
0.020
0.01
0.01
0.00
0.01
0.01
0.01
0.02
0.01
0.01
Mean Difference = 0.008
Concentration =(Peak Height - Base Height) (C/A)
C/A - 0.3333 = Slope of Calibration Curve
86
-------
This introduced error was greatest at low oxygen concentrations,
when increased sensitivity was most desired. This technique, therefore,
was also discarded. The problem was finally resolved by a return
to polarographic methodology.
In polarographic oxygen analysis oxygen diffused through a membrane
is reduced electrochemically, inducing a current which is proportional
to the concentration of oxygen in the sample. Most of the sensors
available for field and laboratory use, however, have relatively large
surface areas which consume excessive amounts of oxygen when tensions
are low. International Biophysics Corporation supplied an IBP bedside
blood oxygen analyzer probe (a hospital unit) and a modified Model
300 compact oxygen analyzer which proved to be satisfactory.
The small sensor from the hospital unit was coupled to the Model 300
meter, the circuitry of which was modified to increase sensitivity
to low oxygen tensions at low temperatures. The sensor has a diameter
of approximately 2.5 mm and is mounted in a plexiglas flow-through
sample chamber which accomodates a 0.25 ml sample. Since oxygenated water
from the previous sample tends to adhere to the plastic walls it is
necessary to flush the chamber with approximately three to four volumes
of each succeeding sample. One problem encountered was drying of
the- membrane. This resulted from rapid evaporation and capillary movement
of electrolyte up the vent tube of the small volume (2 ml of 1M KC1)
electrolyte reservoir. This was overcome by disconnecting the
sensor from the read-out unit at the end of each day, immersing
it in electrolyte, and subjecting it to a strong vacuum. This
forces electrolyte under the membrane and prolongs the life of
the sensor.
Oxygen meter readings are plotted as a function of Winkler oxygen
concentrations to establish a standard curve on any given day the
87
-------
meter is used. Calibrations are made by filling BOD bottles
with various mixtures of aerated and deoxygenated water to create
a graduated series of oxygen concentrations. After zeroing the
meter with nitrogen gas, subsamples from each mixture are injected
into the meter and readings made. Dissolved oxygen content of
the mixtures is then determined by the alkaline azide modification
of the standard Winkler method. The standard curve is plotted
with the meter reading as a function of Winkler oxygen concentration.
The meter-probe combination is stable for 2 to 3 hours, after
which it must be recalibrated.
Typical calibration curves are shown in Figure 22. A distinct
departure from linearity at higher dissolved oxygen concentrations
was observed for those made on September 17 and 24. This condition
improved following development by IBP of an improved sensor. Calibration
curves made after September 24 demonstrated good linearity over a range
of 0-10 mg/1. The slope of the latter curves was nearly the
same, although there was a shift downward with time. This probably
indicates decreased sensitivity of the sensor with use. Gain
on the instrument was not readjusted during this period.
Hydrogen Ion Concentration -
A plexiglas semi-micro combination type pH electrode adapter (Figure 23)
was fabricated to accommodate a 2.5 ml sample volume without
atmospheric contamination. The probe is calibrated while in
the adapter using standard non-phosphate buffers of pH 4.6 (0.2
M KH phthalate and 0.2 M NaOH) and pH 8.0 (0.2 M H BO + 0.2 M
on O O
KC1 and 0.2 M NaOH) .
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Both standards and samples are injected from a syringe into part "A".
Air is expelled from part "B" ahead of the sample and steady pH meter
readings are obtained when the liquid level reaches point "X" in the
adapter.
Oxidation-Reduction Potential (Redox) -
Some of the earlier work on the importance of oxidation-reduction
on
relationships in lakes was carried out by Pearsall and Mortimer ,
who studied the effects of redox potential on several of the
common ions found in lakes, and by Mortimer , who compiled an
extensive treatise on the exchange of dissolved substances between
mud and water in lakes. Many of Mortimer's findings emphasized
the importance of redox changes. He showed that increased concentrations
of ammonia, ferrous iron, and phosphorus at the mud v/ater interface
resulted from oxygen depletion and accompanying reducing conditions.
Hayes, Reid, and Cameron have pointed out several of the problems
associated with redox measurements. These include the lack of
reproducibility in non-poised samples (samples other than standards),
differential readings depending on the area of platinum in the
electrode, hydrogen sulphide alteration of readings, and air
contamination cf samples removed from a reducing environment.
We have minimized the problem of air contamination by making
redox measurements on water from the experimental columns with
an Orion Model 96-78 combination redox probe mounted in a specially
constructed ple:xiglas adapter (Figure 24). The platinum electrode
and fluid junction are seated tightly into the plastic block.
Water samples (2.5 ml) are withdrawn from the columns by syringe
and injected into the sample holding chamber, flushing through
3-4 volumes to expel air and residual sample.
91
-------
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-------
The redox probe is standardized using the potassium ferric and
41
ferrous cyanide solutions descibed by Zobell . Subsequent
readings are corrected to the normal hydrogen electrode (NHE)
according to the formula:
ENHE ' Eo + C
where E.,,,r = oxidation reduction potential of the sample relative
to the NHE
E = potential developed by the platinum redox electrode
C = potential developed by the reference electrode
portion relative to the NHE.
93
-------
TENTATIVE EXPERIMENTAL PROCEDURE
A tentative procedure for the experimental column studies has
been established and partially verified. At this point, however,
an entire experiment has not been completed. A preliminary
test run without radioactive tracers has been conducted to
determine the effect of one candidate inactivant on phosphorus
concentrations, and to verify that the microcosm system functions
as expected. This will be described later in this report.
The tentative experimental procedure is as follows:
DAY EXPERIMENTAL PROCEDURE
A) Nutrient content of sediment.
1) Collect three core samples (see B).
2) Extrude the cores in 1 cm increments (Figure 25),
3) Composite the sequential increments from the
three cores for chemical analysis.
a) Centrifuge the sediment sample in N?-purged
containers for separation into interstitial
water and solid phases.
b) Analyze each phase for total phosphorus,
total nitrogen, iron, and the inactivant
being tested.
B) At the same time collect cores for laboratory work
and six liters of pond water from just above the
sediment. Filter the latter through 0.45 y membrane
filter, divide the filtrate equally between two
containers (replacement water).
94
-------
RUBBER
GASKET
JENKIN CORING TUBE
SEDIMENT
.63 CM.
> .20 CM.
~~*~. > PLASTIC LAMINATED
2.54 CM. r PLUNGER
.OCK NUT
-METAL ROD
Figure 25. Device for extruding sediment samples from
Jenkin coring tubes.
-------
1) Place cores from (B) and replacement water in a
dark environmental chamber at 18°C (approximate
summer bottom temperature of Cline's Pond).
2) After two hours withdraw water samples from port
number 4 with a syringe (ports are numbered from bottom
to top) and analyze for the following parameters:
Analysis Required Hater Volume (ml)
Total soluble phosphorus 2.5
Soluble orthophosphorus 2.5
ATP 5.0 (Filtrate from
above)
Total Phosphorus 2.5
Orthophosphorus
Ammon i a 2.5
Nitrite
Nitrate
5.0
Kjeldahl nitrogen 25.0
Oxygen 2.0
pH 2.5
Redox 2.5
Inactivant material 5.0
37.0
Total volume required for 47.0
complete analysis
3) As water samples are removed from the columns,
replace the volume with replacement water (See B).
4) Start air flow into half the columns and one
replacement water container at 0.25 cc/min.
96
-------
5) Start N2 flow into half the columns and one
replacement water container at 0.25 cc/min.
C) Allow the columns to equilibrate two weeks, rerunning
all of the analyses under B-2 every 2 to 3 days.
32
15 D) Add one mi 11icurie P to the water phase of each
aerobic and anaerobic column.
1) Remeasure the phosphorus concentration (total-P
and soluble ortho-P) in each column after one hour,
during which time air and No flow has continued.
32
2) Measure P in the water.
3) Add nutrient inactivant by syringe through port
number 8 (amount will be dependent on
phosphorus concentration) and continue aeration
and N~ purge for 30 minutes.
4) Terminate air and N2 flow for 24 hours while the
inactivant floe settles to the bottom.
16 5) Inject 0.50 mi Hi curies 33P (contained in 200
micro-liters of water) into the sediment 1.0 cm
below the surface (Figure 26).
6) Resume air and N^.
E) One hour after air-N0 has been resumed, withdraw
samples from port number 4 for complete analysis
series (B-2), excluding Kjeldahl-N. Also analyze for
32 33
P, and P in the water phase:
Analysis Required Water Volume (ml)
32
P 2.5 ml water redox measurement
33p
F) Analyze for all parameters in B-2 (excluding Kjeldahl-N)
and the parameters in F.
G) Tentatively, analysis frequency will be two-day
intervals the first week, three-day intervals the
second, and weekly thereafter.
97
-------
LAMPING SCREWS
JO
DISTRIBUTION PATTERN OF
33P FOLLOWING INJECTION
FROM TWO SIDES
^HYPODERMIC NEEDLE
THREADS
CORING TUBE
SILICONE RUBBER FILLED
^INJECTION PORTS
SLEEVE IN PLEXIGLAS BLOCK
TO ACCOMODATE THE
SYRINGE
SET SCREW
PLEXIGLAS BLOCK (2.54CM)
INJECTION JIG
-MICROLITER SYRINGE
-PLUNGER STOP
'LUNGER
33
Fiqure 26. Jig for injecting P into sediment.
-------
PRELIMINARY DETERMINATION OF INACTIVANT EFFECT
Having resolved the technical problems associated with the chemical
analysis and experimental apparatus, the first inactivant was selected
for effect and stability experiments in the laboratory. The
choice was made on the basis of phosphorus removal capacity,
results of toxicity tests and other information available from
the literature.
Laboratory experiments demonstrated clearly that lanthanum, zirconium,
and aluminum compounds were more efficient phosphorus removers
than any of the other materials tested. Based on phosphorus removal
efficiency alone lanthanum would be the first choice with its 1:1
inactivant to phosphorus molar ratio. The lanthanum rare earth
chloride used in the toxicity experiments, however, demonstrated
a 100 percent mortality to the fish tested when applied at >1
mg/1 lanthanum rare earth chloride. A relatively high mortality
rate for D_. nagna also resulted. The lanthanum mixture was therefore,
not used in this series of tests.
Zirconium removed phosphorus efficiently at an inactivant to phosphorus
molar ratio of approximately 2:1 and was relatively non-toxic
to fish and cladocerans. The optimum phosphorus removal capacity
of zirconium extended over a broad pH range (see Figures 7 and
8). Optimum phosphorus removal with aluminum occurred at a molar
ratio of approximately 8:1 and was confined to a rather narrow
pH range between 4 and 6. Sorbing efficiency decreased rapidly
outside this pH range. The pH of most eutrophic waters is greater
than 6. Zirconium, therefore, possessed more of the characteristics
desired of an inactivant than the other materials tested and
was thus selected as the initial material to undergo more thorough
examination with regard to stability of the inactivation treatment.
99
-------
A preliminary experiment was then conducted to determine the
effect of zirconium tetrachloride on phosphorus concentration
in the test columns prior to beginning the major experiments
32 33
with P and P. Mud-water interface samples were collected
and treated according to the methods described with regard to
sediment level adjustment and set-up of the columns (see Figure
20). The tentative test procedure as described in the foregoing section
was not followed beyond that point with regard to time schedule or
chemical analyses. Phosphorus, oxygen and pH were the only parameters
measured. Four columns were aerated and four purged with nitrogen.
These were arranged in four aerobic-anaerobic pairs. One pair
served as controls and received no treatment other than the gas
flow. The other three pairs received 10, 15, and 17 mg Zr/1
(zirconium tetrachloride solution without neutralization), respectively,
on the 15th day of the experiment (not the same as day 15 under
"Experimental Procedure"). On the 20th day air and nitrogen
flows were reversed, that is, those receiving air were switched
to nitrogen and vice-versa. The experiment was terminated after
34 days.
Results
In columns initially aerated, the total phosphorus concentrations
declined by an average of 44 percent prior to zirconium addition
on day fifteen (Figure 27). On day 16 total phosphorus concentrations
had declined 57, 94, and 91 percent from the previous day in
the'10, 15, and 17 mg Zr/1 columns, respectively. The control
decreased only 5 percent. Total soluble phosphorus (Figure 28)
decreased 89, 100, and 98 percent, respectively, while the control
showed the same 5 percent decrease.
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No increase in phosphorus concentration was evident over the
next five days, and the total phosphorus in the control and 10
mg Zr/1 columns continued to decrease at the same rate as before
inactivation. Following the change to anaerobic conditions after
day twenty, an increase in total phosphorus was noted in all
columns. In the inactivated columns this increase was small.
Concentrations in the control and 10 mg Zr/1 columns decreased
after day 23, increased slightly in the 15 mg Zr/1 column, and
remained unchanged in the 17 mg Zr/1 column. Total soluble
phosphorus showed no increase until day 34 when a maximum increase
of 0.03 mg P/l was noted in the 10 mg Zr/1 column.
Decreasing phosphorus concentrations during the initial aeration
period (days 1-5) were probably due to high oxygen concentration
and associated moderate pH levels (Figure 29). On the third
day of the experiment the pH of all four columns was about 6.8.
On the day following zirconium addition pH values were 7.05,
6.75, 5.90, and 5.45 in the control and the 10, 15, and 17 mg Zr/1
columns, respectively. The inactivant solution was not neutralized,
thus the hydrochloric acid formed during the hydrolysis of ZrCl.
was responsible for rapid pH reduction. Five days after treatment
the lower pH levels had increased under the continued aeration.
On the 20th dey, five days after treatment, aeration was replaced
by nitrogen purging. By the 22nd day pH levels of all columns
were nearly identical, and close to the original values.
Figure 30 shows that total phosphorus concentrations in the initially
anaerobic columns increased by an average of 30 percent over
the 15 day period before zirconium addition. Increases for the
four columns ranged from 24 to 41 percent.
103
-------
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On day 16, the day following zirconium treatment, tctal soluble
phosphorus concentrations had declined from those of the previous
day by 67, 95, and 93 percent for the columns treated with 10,
15, and 17 mg Zr/1, respectively. Total phosphorus decreased
in the control by 28 percent. Total soluble phosphorus decreases
for the same period were 94, 94, and 97 percent, respectively,
with the control column showing no change (Figure 31).
In the nitrogen purged columns (Figure 32) pH was the same (approximately
7.0) as in the aerated columns on day 3 of the experiment. On
day 16 (one day after zirconium tetrachloride treatment) pH values
of the two systems were more varied with greater depression of
pH in the aerobic than in the anaerobic columns. Under anaerobic
conditions a minimum pH of 6.4 was noted in the 17 mg Zr/1 column
on day 16. In contrast to the aerated system, pH recovery in
the anaerobic columns was quite rapid. Four days after zirconium
inactivation (Day 19) the pH had risen in all columns to 7.2,
and 2 days later had returned to approximately 7, remaining at
that level until termination of the experiment. Recovery to
the initial pH in the aerated columns required nearly twice as
long. The difference in pH behavior between the nitrogen purged
and aerated columns may have been the result of an ammonium
carbonate buffering system operating under anaerobic conditions,
while in the aerated system ammonia would have been rapidly
oxidized. This possibility will be examined in future experiments
when inorganic nitrogen fractions in the test columns will be
monitored.
Total phosphorus remained low (it decreased even further for
the 10 mg Zr/1 treatment) for the remainder of the experiment.
The change-over from nitrogen to air on day 20 may have contributed
to the continued low levels. Total soluble phosphorus was at
106
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a minimum on day 16 following inactivation, but the 10 mg Zr/1
column showed an increase at day 20 just prior to switching
from nitrogen to air. By day 23 total soluble phosphorus in
that column was again reduced and remained constant until the
experiment terminated. The other experimental columns showed
no change in phosphorus concentration from date of inactivation
onward.
Although the data are not conclusive, it appears that anaerobic
conditions may contribute to the slow release of some soluble
phosphorus fraction from the sediment or the zirconium-phosphorus
complex. The fraction is extremely small, however, and will
be examined more closely in the experiments using phosphorus
isotopes.
Decreased phosphorus levels in the controls after the 15th day
are not understood at this point. Development of an air leak
is one possibility, but total phosphorus analyses for that day
are also suspect. This phenomenon will be scrutinized closely
in subsequent experiments.
Discussion
Results of the preliminary laboratory study confirm that the experimental
procedure and sediment-water systems perform as anticipated. Under
anaerobic conditions prior to inactivation there was apparently
109
-------
substantial release of phosphorus from the sediment to the overlying
water, while aerating resulted in a phosphorus concentration decline.
Treatment of the "columns" with crude zirconium tetrachloride
produced a precipitous drop in the phosphorus concentrations.
When treated at the rate of 15 and 17 mg Zr/1 the soluble phosphorus
levels were reduced by 94 to 97 percent under both aerobic and
anaerobic conditions.
In the toxicity experiments zirconium tetrachloride concentrations
up to 20 mg Zr/1 did not produce a 96 hour TL . The 9-week
experiments produce TL values at < 20 mg Zr/1 with D. magna;
m
however, this represented the worst possible condition, in which
the organisms were continually subjected to reconstituted solutions
of the inactivant each week over a nine-week period. The column
experiments and any field applications of zirconium probably
would be more nearly represented by the 96 hour toxicity experiments,
since the zirconium floe is dense and settles rapidly to the
bottom. The concentration of zirconium remaining in solution
is unknown at present but preserved samples will be analyzed shortly.
An initial shock to aquatic organisms due to concentration of
the inactivant at the surface is a possibility in field applications;
however, it would normally be of short duration. In jar tests
all visible zirconium floe settled to the bottom in less than
1 hour. Therefore, treatment of the columns with 15 to 17 mg
Zr/1, as in the preliminary experiment, would remove approximately
94 to 97 percent of the soluble phosphorus from the water and
would probably be relatively non-injurious to the majority of
the pelagic aquatic organisms (Ostracods were observed in several
of the columns following treatment).
110
-------
The pH in treated columns dropped to a low of 5.45 with the
addition of 17 mg Zr/1 under aerated conditions. Although recovery
to the original pH of approximately seven required only three
days, a pH shock of that magnitude and duration could be extremely
detrimental tc many aquatic organisms. The column experiments
demonstrated cgain that pH adjustment is critical when zirconium
tetrachloride is used in poorly buffered waters. Adjustment of pH
would be of far less concern in well buffered water systems.
The most encouraging information from the preliminary experiment
was that the soluble phosphorus levels, once reduced by inactivation,
tended to remain low for the duration of the experiment in both the
aerobic and anaerobic systems. A slight increase in total phosphorus
levels occurred 20 days after inactivation; it is necessary to know
whether this phosphorus was resolubilized from the inactivant-
phosphorus complex or originated from the sediment beneath the
inactivant-phosphorus layer. The dual phosphorus tracer experiments
are expected to shed light on this problem. If so, the techniques
using sediment-water columns may be refined into a method for calculating
the exchangeable phosphorus content of lake sediments, a problem which
has plagued limnologists and systems ecologists for some time.
Ill
-------
VIII. AVAILABILITY AND COSTS OF INACTIVANTS
An important criterion for determining the suitability of a material
as a practical nutrient inactivant is its availability and cost.
Depending on the phosphorus removal characteristics of the material,
the size of the lake, its phosphorus concentration, and the proximity of
the lake to sources of supply, both the quantity of inactivant
needed and the total cost of treatment could vary over a wide
range.
Very large lakes probably would not be subjected to nutrient inactivation;
quantities, costs, and mechanics of application would become prohibitive.
If field testing verifies the operational capability and reliability
of the technique, however, it could conceivably be applied to
many smaller, overly productive lakes throughout the country.
Information from the literature indicates that world supplies
of zirconium and rare earths are sufficiently great to allow consideration
of these materials for lake restoration. According to Kleber and
42
Love, total rare earths are about half as abundant as carbon
or chlorine, in the same range of abundance as chromium, vanadium,
or zinc, and more abundant than nickel or copper. The annual
United States production capacity of rare earths of the cerium
group (of which lanthanum constitutes about 25 percent) is estimated
by Kleber and Love at 20,000-25,000 tons. The potential
available supply, however, is in the range of hundreds of thousands
of tons from undeveloped domestic sources alone. These minerals
presumably would become available on demand.
112
-------
The present United States demand for zirconium is about 72,000
tons of ore per year, most of which is imported from Australia.
n o
Reserves in that country are estimated at 3,250,000 tons.
Other sources would be expected to become available if demand
increased.
As an illustration of the quantities of inactivants which might
actually be required in the treatment of a eutrophic lake, we
have computed the amounts of lanthanum, zirconium, and aluminum
which would be needed to inactivate all the phosphorus in Diamond
/- o
Lake, Oregon, a moderately eutrophic lake with a volume of 90 x 10° m
and a mean total phosphorus content of 2900 kg. Using values
obtained with Cline's Pond water from the jar tests, the following
calculations were made:
Lanthanum rare earth carbonate: 24,600 kg
Lanthanum rare earth chloride: 33,400 kg
Zirconyl chloride: 60,260 kg
Zirconium tetrachloride: 65,390 kg
Sodium al'jminate: 53,600 kg
These numbers are qualitative estimates, being based only on
the results of preliminary laboratory tests. They do, however,
provide a reasonable idea of the order of magnitude of quantities
needed in full scale operations. Diamond Lake is a relatively
large lake, with a surface area of approximately 13,000 ha,
but its phosphorus content can only be considered moderate. Phosphorus
concentrations in many problem lakes could be a number of times
greater. On the other hand, lakes selected for nutrient iriactivation
are likely to be small and require only moderate quantities of
inactivant.
113
-------
The costs of inactivation are also difficult to estimate because
of variation in availability of materials from place to place,
and the cost of transporting them to the lake. Some recent estimates
of approximate costs per kilogram for various possible inactivants
at their source are as follows:
lanthanum rare earth carbonate $1.43
lanthanum rare earth chloride 0.64
zirconyl chloride 1.10
zirconium tetrachloride 1.10
sodium aluminate 0.22
aluminum sulfate 0.07
These are estimates only and actual prices will vary with location,
purity of products and other factors. Further research should
show whether performance characteristics of more expensive inactivants
will warrant the higher initial cost. Stability of the treatment
with the various inactivants will be an important consideration in
determining their actual cost.
114
-------
IX. REFERENCES
1. Jernelov, A., and G. Lundstrom. Results from chemical-
physical investigations in Lake Langsjon, April 1968 to
January 1969. Swedish Water and Air Poll. Res. Lab.
Stockholm, Sweden. 1970. 7 p.
2. Jernelov, A. Phosphate reduction in lakes by precipitation
with aluminum sulphate. Presented at Fifth Internat. Water
Poll. Res. Conf., San Francisco, Calif. July-Aug. 1970.
p. 115-1 to 115-6.
3. Landner, L. Lake Restoration. Trials with direct precipitation
of phosphorus in polluted lakes; the binding of mercury in
lakes; trials with grass carp. Presented at Internat. Expo.
on World, Water, and We, Jonkoping, Sweden. Nov. 1970. 9 p.
4. Peterson, J. 0., J. P. Wall, T. L. Wirth, and S. M. Born.
Eutrophication Control: Nutrient inactivation by chemical
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Res., Madison, Wise. Tech. Bull. No. 62, Dept. of Nat. Res.
1973. 20 p.
5. Dunst, R., S. Born, P. Uttormark, S. Smith, S. Nichols, J. Peterson,
D. Knauer, S. Serns, D. Winter, T. Worth. Survey of Lake
Rehabilitation Techniques and Experience. Inland Lakes Demonstration
Projects. Upper Great Lakes Regional Commission. 1974. 179 p.
6. Sanville, W. D., A. R. Gahler, J. A. Searcy, and C. F. Powers.
Studies on lake restoration by phosphorus inactivation. Unpublished
manuscript. 65 p.
7. Natioral Eutrophication Research Program, EPA. Algal Assay
Procedure, Bottle Test, Environmental Protection Agency, Corvallis,
OR. Aug. 1971. 82 p.
8. Environmental Protection Agency. Methods for Chemical Analysis
of Water and Wastes. Cincinnati, Ohio. Pub. No. 16020-07/71.
1971. 312 p.
9. Hsu, P. H. Removal of Phosphate from Wastewater by Aluminum and
Iron, Phase II. New Jersey Water Resources Research Institute,
Rutgers State University, New Brunswick. Dec. 1970. 5 p.
115
-------
12.
13.
10. Recht, H. L., M. Ghassemi, and E. V. Kleber. Precipitation
of Phosphates from Water and Wastewater Using Lanthanum Salts.
North American Rockwell Corp., San Francisco. Paper 1-17,
Fifth International Water Pollution Research Conference, July 1970.
12 p.
11. Recht, H. L. and M. Ghassemi. Phosphate Removal from Wastewater
Using Lanthanum Precipitation. North American Rockwell Corp.,
U. S. Government Printing Office, Washington D. C. Pub. No.
17010 EFX 04/71, U.S. Dept. of the Interior. April 1970. 45 p.
Volk, V. V., J. W. Lee, Jr., and E. C. Y. Kuo. Land Disposal
of Refractory Metal Processing Wastes. Unpublished Manuscript.
Yuan, W. L., and P. H. Hsu. Effect of Foreign Components on the
Precipitation of Phosphate by Aluminum. Rutgers State Univ.
New Brunswick, NJ. Paper 1-16, Fifth International Water
Poll. Res. Conf. Aug. 1970. 12 p.
14. Standard Methods for the Examination of Water and Wastewater.
Thirteenth Edition. American Public Health Association. 1971.
15. Nebeker, A. V. and F. A. Puglisi. Effects of Polychlorinated
Biphenyls (PCB's) on Survival and Reproduction of Daphnia,
Garnmarus and the Midge Tanytarsus. Submitted to Transactions
of the American Fisheries Society, 1972.
16. Nebeker, A. V. Effect of Low Oxygen Concentration on Survival
and Emergence of Aquatic Insects. Trans. AM. Fish. Soc. 101:675-679,
October 1972.
17. Bell, A. L. Effects of pH on the Life Cycle of the Midge
Tanytars us di ss imi Ijj^. The Canadian Entomologist. 102:
636-639, May~T97UT~~
18. Everhart, W. H. and R. A. Freeman. Effects of Chemical Variations
in Aquatic Environments: Volume II. Toxic Effects of Aqueous
Aluminum to Rainbow Trout. Environmental Protection Agency,
Duluth, Minnesota, Report No. EPA-R3-73-0116. February 1973. 41 p.
19. Anderson, B. G. The Apparent Thresholds of Toxicity to Daphnia
magna for Chlorides of Various Metals When Added to Lake Erie
WateT. Trans. Am. Fish. Soc. 78^:96-113, 1948.
20. Pulley, T. E. The Effects of Aluminum Chloride in Small
Concentrations on Various Marine Organisms. Texas Jour.
Sci . 3^:405-411, September 1950.
116
-------
21. Water Quality Criteria. McKee, J. E. and H. W. Wolf (eds.)
Sacramento, California, State Water Quality Control Board,
Pub. No. 3-A, 1963. p. 548.
22. Biesinger, K. E. and G. M. Christensen. Effects of Various
Metals on Survival, Growth, Reproduction and Metabolism of
Daphnia magna. J. Fish. Res. Bd. Can. 29_: 1691-1700,
December" 1972.
23. Well, J. P., J. 0. Peterson, T. L. Wirth, and S. M. Born.
Horseshoe Lake: Nutrient Inactivation by Chemical Precipitation.
Preliminary Report. Upper Great Lakes Regional Commission, 1971.
24. Cochran, K. W., J. Doull, M. Mazur, and K. P. DuBois. Acute
Toxicity of Zirconium, Columbium, Strontium, Lanthanum, Cesium,
Tantalum, and Yttrium. Arch. Ind. Hyg. Occup. Med. ]_: 637-650,
1950.
25. Palange, R. C., C. C. Henderson, J. M. Cohen, and G. N. McDermott.
Wastes From the Production of Reactor-Grade Zirconium. Sewage
and Industrial Wastes, 3Jh565-573, 1959.
26. Tarzwell, C. M., and C. Henderson. The Toxicity of Some of the
Less Common Metals to Fishes. In: Trans. Seminar on Sanitary
Engineering Aspects of the Atomic Energy Industry. Robt. A.
Taft, San. Engrg. Center, Cincinnati, Report Mo. T I D-7517, 1956.
27. Collier, A. Titanium and Zirconium in Bloom of Gymnodinium
brevis Davis. Science ]_1_8:329, 1953.
28. Kyker, G. C. and E. A. Cress. Acute Toxicity of Yttrium,
Lanthanum and Other Rare Earths. AMA Arch. Ind. Health.
16:475-479, December 1957.
29. Bringmann, G. and R. Kuhn. The Toxic Effects of Wastewater
on Aquatic Bacteria, Algae, and Small Crustaceans. Gesundheits-
Ing. 80:115, 1959.
30. Mortimer, C. H. The Exchange of Dissolved Substances
Between Mud and Water in Lakes. J. Ecol., 2^9:280-329.
and 30:147-201, 1942.
31. Murphy, J. and J. Riley. A Modified Single Solution
Method for the Determination of Phosphate in Natural Waters.
Anal. Chem. Acta., 27:31-33, 1962.
117
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32. Carpenter, J. H. The Chesapeake Bay Institute Technique
for the Winkler Dissolved Oxygen Method. Limnol. Ocean. 10:141-143,
1965. ~
33. Koch, C. J. and Jack Kruuv. Measurements of Very
Low Oxygen Tensions in Unstirred Liquids. Analytical Chemistry
4_4:1258-63, 1972.
34. Bungay, H. R. Ill, W. J. Whalen, and W. M. Sanders, III.
Microprobe Techniques for Determining Diffusivities
and Respiration Rates in Microbial Slime Systems. Biotechnology
and Bioengineering 11:765-772, 1969.
35. Sanders, W. M. , III, H. R. Bungay, III, and W. J. Whalen.
Oxygen Microprobe Studies of Microbial Slime Films.
Chemical Engineering Symposium Series, 67^69-74, 1970.
36. Whalen, W. J., H. R. Bungay, III, and W. M. Sanders, III.
Microelectrode Determination of Oxygen Profiles in
Microbial Slime Systems. Environmental Science and Technology
3^:1297-98, 1969.
37. Whitney, R. J. A Syringe Pipette Method for the
Determination of Oxyqen in the Field, Jour. Exper. Biol.
1_5:564-570,,1938.
38. Danials, F. J., H. Mathews, and J. W. William. Experimental
Physical Chemistry. McGraw-Hill Inc. Chapter
XXXIII pp. 439-442, 1941.
39. Pearsall, W. H. and C. H. Mortimer. Oxidation-
Reduction Potentials in Water-Logged Soils, Natural Waters
and Muds. J. Ecol. 27:483-501, 1939.
40. Hayes, F. R., B. L. Reid, and M. L. Cameron. Lake
Water and Sediment. II. Oxidation-reduction relations at
the mud-water interface. Limnol. Oceanog. 3^308-317, 1953.
41. Zobell , C. Studies on Redox Potential of Marine
Sediments. Amer. Asso. Petro. Geol. Bulletin.
3_£:477-513, 1946.
42. Kleber, E. V., and B. Love. The Technology of Scandium,
Yttrium, and the Rare Earth Metals. The MacMillan Company,
New York, 1963.
43. R. R. Wells, U. S. Bureau of Mines, Albany, OR.
Personal Communication.
11!
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-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i. REPORT NO.
EPA-660/3-74-032
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
Nutrient Inactivation as a Lake Restoration Procedure.
Laboratory Investigations
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Spencer A. Peterson, William D. Sanville, Frank S. Stay,
Charles F. Powers
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Eutrophication and Lake Restoration Branch
Pacific NW Environmental Research Lab
NERC-Corvallis, USEPA
200 SW 35th Street, Corvallis, OR 97330
10. PROGRAM ELEMENT NO.
1BA031
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Same as 9
13. TYPE OF REPORT AND PERIOD COVERED
Interim. July 1972-Nov. 1973
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Compounds of certain metals are known to be capable of complexing phosphate
ions, thereby removing them from solution. The application of this principle to
the control of phosphorus levels in eutrophic lakes has been subjected to laboratory
investigation in the present study. Salts of lanthanum, zirconium, and aluminum
were found to effectively remove phosphorus from laboratory growth medium and
natural pond water, with resulting depression of algal production. Toxicity to
fishes and aquatic invertebrates was minimal, but the tests demonstrated that some
components of metals salts may have adverse effects. The stability and duration
of phosphorus inactivation is being studied in laboratory-scale water-sediment
systems, under aerobic and anaerobic conditions. These experiments are expected
to elucidate the effect of inactivant-phosphate precipitates on sediment-water
phosphorus interchange. Preliminary results indicate that zirconium precipitates
phosphorus from the water and holds it at low levels.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Eutrophication, Nutrient Removal,
Phosphorus, Sediment-Water Interfaces;
Algal Control, Aluminum
Inactivation,
Zirconium,
Rare Earths,
Cline's Pond
05 C
3. DISTRIBUTION STATEMEN1
Release unlimited
19. SECURITY CLASS (This Report)
21. NO. OF PAGES
118
20. SECURITY CLASS (This page)
22. PRICE
EPA Form 2220-1 (9-73)
U.S. GOVERNMENT PRINTING OFFICE 1975-697-618/76 REGION 10
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