(excerpt)
The ubiquity and refractory nature of certain organic compounds, such as chlorinated pesticides and polychlorinated biphenyls (PCB\u27s), results in their accumulation in aquatic sediments (Holdrinet et al. 1978, Peck et al. 1980, Wang et al. 1979). Their continuous release from this reservoir through physico-chemical and biogenic processes to the overlying water column results in the accumulation of xenobiotic compounds in the food chain

Meier, Peter G

Roberts, Dale

English

ValpoScholar

The Great Lakes Entomologist 
Volume 15 
Number 1 - Spring 1982 Number 1 - Spring 1982 Article 10 
April 1982 
A New Method for Exposing Deposit Feeders to Contaminated 
Sediments for Food Chain Studies 
Dale Roberts 
University of Michigan 
Peter G. Meier 
University of Michigan 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Roberts, Dale and Meier, Peter G. 1982. "A New Method for Exposing Deposit Feeders to Contaminated 
Sediments for Food Chain Studies," The Great Lakes Entomologist, vol 15 (1) 
Available at: https://scholar.valpo.edu/tgle/vol15/iss1/10 
This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. 
It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. 
For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 
1982 THE GREAT LAKES ENTOMOLOGIST 59 
A NEW METHOD FOR EXPOSING DEPOSIT FEEDERS TO 

CONTAMINATED SEDIMENTS FOR FOOD CHAIN STUDIES 

Dale Roberts and Peter G. Meier l 
The ubiquity and refractory nature of certain organic compounds, such as chlorinated 
pesticides and polychlorinated biphenyls (PCB's), results in their accumulation in aquatic 
sediments <Holdrinet et al. 1978, Peck et al. 1980, Wang et al. 1979). Their continuous 
release from this reservoir through physico-chemical and biogenic processes to the over­
lying water column results in the accumulation of xenobiotic compounds n the food chain. 
Accumulation of organics within organisms can be accomplished through several routes. 
Direct uptake from water across gill and membrane surfaces bas been suggested by some as 
the main mechanism (Nisbet and Sarofim 1972, Fowler et al. 1978). Others have shown that 
the accumulation by aquatic invertebrates and fish is a two step process: desorption from 
sediments into water and uptake from water by the biota (Halter and Johnson 1977). Recent 
studies have documented the importance of direct uptake of organics by sediment-ingesting 
benthos (Fowler et al. 1978, Langston 1978, Meier and Rediske 1979). However, contro­
versy still exists as to the role water and/or sediment concentrations play regarding accumu­
lation and biomagnification of these compounds in food chains. 
In examining the uptake and behavior of organics in food chain organisms, it is important 
to 
expose test animals 
in such a manner that the results are reproducible, statistically 
significant, and applicable to natural systems. Several methods have been described in the 
literature. Researchers who exposed algae and/or invertebrates to contaminated water failed 
to consider the role of sediments in studies concerning low water soluble compounds. Often 
these exposures are made at artificially high concentrations of test material in water (Hattula 
and Karlog 1973, Melancon and Lech 1976, Sandlers and Chandler 1972). In other food 
chain studies, test animals were fed a contaminated synthetic processed food which did not 
simulate natural conditions (Zitko 1974, 1977; Hanson et al 1976; Narborne 1979). 
The 
purpose 
of the study was to develop a method that would aid in food chain studies by 
providing: (I) A predictive capability through manipulation of the biomass-sediment ratio to 
achieve the desired body burden in the food organism; (2) A large number of sediment 
associated organisms with similar body burdens; (3) An application in a variety of situations 
with different substances and test organisms; and (4) Repro ucible results. 
MATERIALS AND METHODS 
Test 
organisms were larvae 
of Chironomus plumosus Meigen (Diptera: Chironomidae) 
collected from oxidation lagoons in Fowlerville, Michigan. These midges were maintained in 
38-liter aquaria according to the method described by Meier and Torres (1978) (Fig. I). The 
numerous egg masses obtained from the adults of the wild collection served as the-starting 
material for the laboratory culture. Background concentration of PCB's in the midges was 
insignificant at an analytical level of <0.05 jJ.g/g wet weight. 
The polychlorinated biphenyl used in this study was 14C labeled 2,4,5,2' ,4',5' hexa­
chlorobiphenyl packaged in crystalline form at 1.5 mg per vial. 2 The content was dissolved 
with 15 ml of acetone and then diluted with distilled water to a concentration of 0.1 mg/ml. 
This stock solution was added in specific volumes to each of the in ubation vessels for the 
desired concentration, 
1 Department of Environmental and Industrial Health, School of Public Health, The University of 
Michigan, Ann Arbor, MI 48109. 
2Source: California Bionuclear Corporation; Specific Gravity: (mCi/I11i\.!.)24; Activity per vial: 
0.1 mCi. 
1
Roberts and Meier: A New Method for Exposing Deposit Feeders to Contaminated Sedimen
Published by ValpoScholar, 1982
60 THE GREAT LAKES ENTOMOLOGIST Vol. IS, No. I 
Air Line 
(I) 	Adult Emergence Air Line 

"Lagoon- Water 
 Air Line 
..::--_ Egg ~Masses "Lagoon­
. I Water Column 
(II) Mating and C·: ../~ Ma:~~s /7­Egg-Laying /r-substrate 
(III) Incubation //
.-"r-
Ycur.~ 
(IV) Maturaticr cf Yeer>; 
Fig. I. Schematic representation of laboratory culture of Chi onomus p!um05us. 
From air SOUrce 
Car::::r' F';!<.::!" ~ 
(!::~J:.. =~ ~) 
Bottle 001 Bottle 002 Bottle 003 Bottle 004 Bottle 005 Bottle 006 
Fig. 2. Design of midge dosing chamber. 
The exposure apparatus for the midges consisted of six 4-liter glass chambers IFig. 2). 
Each vessel was sealed airtight with silicone rubber, except for an inlet and outlet. The 
incoming air 
was filtered 
through a carbon column which removed any potential con­
taminants 
(i.e. oil 
and PCB's) from the hydraulic pump of the aeration system. The outgoing 
air was passed through another carbon 
filter 
to remove any PCB passing out from the 
chambers. For more volatile compounds, this set up can be modified with the addition of 
secondary butyl 
alcohol 
and potassium hydroxide trap in series behind each chamber. These 
compartments may then 
be 
analyzed separately and summed for obtaining a mass balance. 
Preliminary studies showed that 
midge larvae in 
the closed system readily and quickly 
accumulated sediment-associated PCB as 
a result 
of ingestion. These tests helped in de­
termining the sediment to 
biomass ratio 
which most effectively and efficiently met the 
objectives. Hence, 25 
g 
of paper towel (dry weight) were macerated in a blender with I liter 
of 
distilled 
water and poured in each chamber. An additional 2 liters of water containing the 
2
The Great Lakes Entomologist, Vol. 15, No. 1 [1982], Art. 10
https://scholar.valpo.edu/tgle/vol15/iss1/10
1982 THE GREAT LAKES ENTOMOLOGIST 	 61 
necessary amount of 14C labeled PCB in solution, were added to the vessels. Each was 
stirred by aeration for 24 h to assure even distribution of PCB and adsorption onto the 
macerated paper substrate. A small amount of midge food was then added (Meier and Torres 
1978). 
After 6 h, 
20 g of III and IV instar midge larvae were transferred to each chamber. 
The larvae rapidly settled into the sediment and started feeding o  the bacteria-enriched 
sediment. The flow of air to the vessels was then reduced to minimize the disturbance of the 
settled substrate. Each uptake experiment lasted approximately two weeks over which 
period the midges accumulated predictable body burdens of PCB. Food was added once 
every 
three days and the water was changed once a week. 
Replicate dosing chambers contained I, 
10, and 100 [.Lgfg of PCB-contaminated substrate. 
On 
alternating days each vessel was analyzed for 
[14C] PCB in the water, in sediments, and 
in midges. These samples were appropriately treated and analyzed by the liquid scintillation 
method (Wang and Willis 1%5). A standard quench curve was generated for converting 
counts-per-minute to actual disintegrations-per-minute (dpm). The dpm were converted to 
[.Lg/g 
PCB by utilizing 
the specific activity of the labeled chlorobiphenyl. The concentration 
of 
PCB was plotted against time 
to generate the necessary uptake. The experiment was 
terminated when the midge population reached desired body burdens of 1,10, and 100 [.Lgfg. 
The larvae were separated from the sediments, washed, and then frozen for the food chain 
study 
(Meier and Roberts, in press). These experiments were repeated seven times to assure their 
reproducibility and also to obtain sufficient biomass 
of labeled midge larvae. Later 
dosings were sampled only intermittently, since dosing criteria had been established from 
the first experiment. 
RESULTS AND DISCUSSION 
Uptake of Sedimentary PCB by Chironomids: Preliminary Study 
A preliminary experiment was performed to aid in determining the dosing criteria for the 
midge uptake study. By examining the uptake characteristics in a saturated system (30 g 
midge larvae to 10 g sediments) one could design future dosings so as to best achieve the 
goal of producing large numbers of midge larvae with similar body burdens. In the pre­
liminary study, different compartments were examined over time to determine the fate of the 
PCB in the dosing chamber. The results demonstrated the efficiency by midges in stripping 
off 
sedimented PCBs and incorporating them quickly (Fig. 
3). The body burden of 3 [.Lgfg 
10 
C. p1 umosus 
• 
4 
2 
11........ 	 Sediments 

..-....................................... 
.fC---r-,----;-,---T--.-'---T'~r="'F".•=.."T............ ,......~...."" 

o 	 2 4 5 6 7 8 9 10 11 12 13 14 
TIME OF OBSERVATION 
(days) 
Fig. 3. Preliminary study: Plot of PCB concentration in sediments and the corresponding PCB uptake by 
Chiranomus plumasus larvae in fLg/g wet weight. 
3
Roberts and Meier: A New Method for Exposing Deposit Feeders to Contaminated Sedimen
Published by ValpoScholar, 1982
62 THE GREAT LAKES ENTOMOLOGIST Vol. 15. ::-io. I 
was established almost immediately. A mass balance petformed on the sediments and larvae 
amounted to 
95% 
of the added PCB. The unaccounted portion was most likely either sus­
pended or 
dissolved 
in the water column. As the result of this investigation. dosing param­
eters 
for the actual 
uptake studies were set at 20 g larvae and 25 g contaminated sediment for 
each 
chamber. The limiting effect 
of sediment mass and PCB concentration a,oided drasti­
cally overshooting the desired levels of the chemical in the insect as well as maximizing 
sediment-organism content. 
Uptake of Sedimentary PCB by Chironomids: Actual Stud~ 
Seven 
separate uptake experiments, each with three different concentrations. were car­
ried 
out employing this method. The results showed that benthic organisms can accumulate 
significan  concent ations of PCB through direct uptake from contaminated sediments over 
a short time. In addition, the final concentrations of PCB at each dosing level for all experi­
ments were very similar (Table I). Besides that, large numbers of labeled food organisms 
were prepared for food chain studies. 
The 
uptake 
of the radio-chemical followed first ord r rate kinetics after -lS h and showed a 
dose-dependent relationship between substrate concentration and body b-urden. lbe initial 
nonlinear portion of the uptake curve for each concentration was attrib-uted ro fiIIing the 
intestinal tract with contaminated sediment (Fig. 4). Some f the contaminated l.a.nae .... ere 
placed in clean sediments for 24 h and their body burdens were reduced. lbe procedure of 
facilitated removal of contaminated gut material was no  pr cticed in the actual dosing srudy 
since consumer· predators ingest entire organisms, including gut material. 
Figure 4 summarizes graphically the range of uptake concentrations in midges fiX the high 
120 
110 
100 
90 
80 
70 
'" 
60 g­
50 
40 
30 
20 
10 
., :3 .­
DAYS 
Fig. 4. Summary of sedimentary PCB uptake by Chironomus plumasllJ at a sediment concentration of 
10 jJ.g/g 
for 
all experiments. 
4
The Great Lakes Entomologist, Vol. 15, No. 1 [1982], Art. 10
https://scholar.valpo.edu/tgle/vol15/iss1/10
1982 THE GREAT LAKES ENTOMOLOGIST 	 63 
Table 1. Summary of the final biomass concentrations 
of 
PCB 
in C. plumosus for the seven sets of dosings. 
Concentrations are given on a wet-weight basis (p.g/g). 
Sediment Concentration 
Date 1 p.g/g 10 p.g/g 100 p.g/g 
15/8/79 0,1213 1.2212 12.0548 
5/9/79 0.1083 1. 1321 10.5 63 
24/9/79 0.0983 0.9976 10.0041 
15/10/79 0.0898 0.9296 8.8714 
8/11/79 0.1146 1.1869 11.3847 
11/1/80 0.0866 0.8971 9.4836 
25/1/80 0.1018 1.0792 1 .0616 
Mean 
0.1028 
1.0633 10.2494 
SD 
0.0127 0,1217 1.3507 
dosing level 
over time. Following the initial fast uptake, the body burdens were increasing 
consistently to the desired levels. The projected concentrations were reached for all levels of 
exposure in a two-week period for all sets of dosing. Approximately 3500 midge larvae of 
similar body burden and weight were obtained for each level of exposure for use in the 
second 
step uptake studies with fish. In 
summary, this economical method permits the researcher 
to manipulate the organism­
sed ment atio to assure pre-determined body burdens in test organisms. I  addition, this 
technique is applicable in preparing large quantities of sediment ingesting organisms (natural 
food) that have a similar concentration for food chain studies. Finally, this method does 
produce reproducible results in batch experiments. 
LITERATURE CITED 
Fowler, S. W., G. G. Polikarpov, D. L. Elder, P. Parsi and J. P. Villeneuve. 1978. Poly­
chlorinated biphenyls: Accumulation and contaminated sediments and water by the 
polychaete (Nerds diversicolor). Marine BioI. 45:265-272. 
Halter, M. T. and H. F. Johnson. 1977. A model system to study desorption and biological 
availability of PCB in hydrosoils. Aquatic Tox, Hazard Eval. Amer. Soc. Test. Mat. STP 
634: 178-195. 
Hansen, 	L. G., W. B. Weikhorst and J. Simon. 1976. Effect of dietary Aroclor 1242 on 
channel catfish (lctalurus punctatus) and the selective accumulation of PCB compounds. 
1. 
Fish. Res. Bd. Canada 133:1343-1352. 
Hattula, 
M. L. and D. Karlog. 1973. Absorption and elimination of polychlorinated bi­
phenyls (PCBs) in goldfish. Acta Pharmacol. et Tox. 32:237-245. 
Holdrinet, M. V. H., F Frank, R. L. Thomas and L. S. Hetling. 1978. Mirex in the 
sediments of Lake Ontario. J. Great Lakes Res. 4:69-74. . 
Langston, W. 1. 1978. Accumulation of polychlorinated biphenyls in the cockle (Cerasta­
derma edule) and the tellin (Macoma balthica). Marine BioI. 45:265-272. 
Meier, P. G. and R. Rediske. 1979. The effect of sediment oil contamination on the bio­
accumulation and excretion of Arochlor 1242 by chironomid larvae. Michigan Sea Grant 
Program. MICHU-SG:79-207. 
Meier, 	P. G. and H. Torres. 1978. A modified method of rearing midges (Diptera: 
Chironomidae). Great Lakes Entomol. 11:89-91. 
Meier, P. G. and D. Roberts. The uptake and excretion of hexachlorobiphenyl in fathead 
minnows. (in press) 
5
Roberts and Meier: A New Method for Exposing Deposit Feeders to Contaminated Sedimen
Published by ValpoScholar, 1982
64 THE GREAT LAKES ENTOMOLOGIST Vol. 15, No.1 
Melancon, M. J., Jr. and J. J. Lech. 1976. Isolation and identification of a polar metabolite of 
tetrachlorobiphenyl from the bile f ra nbow trout exposed to 14C-tetrachlorobiphenyl. 
Bull. Environ. Contam. Tox. 15:181-188. 
Narbome, 
J. F. 
1979. Accumulation of PCB (Phenochlor DPG) by estuarine Fish. Bull. 
Environ. Contam. Tox. 22:60-64. 
Nisbet, C. T. and A. F. Sarofim. 1972. Rates and routes of transport of PCBs in the 
environment. Environ. Health Perspectives. 1:21-38. 
Peck, D. E., D. L. Corwin and W. J. Farmen. 1980. Adsorption-desorption f Diuron by 
freshwater sediments. 1. Environ. Quality. 9:101-106. 
Sandlers, H. O. and J. H. Chandler. 1972. Biological magnification o  a polychlorinated 
biphenyl (Aroclor 1254) from water by aquatic invertebrates. Bull. Environ. Contam. 
Tox. 7:257-262. 
Wang, C. H. and D. L. Willis. 1%5. Radiotracer methodology in biological ;;.;;iences. 
Prentice-Hall, NY. 
Wang, T. C .• J. P Krivan, Jr. and R. S. Johnson. 1979. Residues of polychlorinated bi­
phenyls and DDT in water and sediments of he St. Lucie estuary Florida. 19-. Pest. 
Mont. J. 13:69. 
Zitko, V. 1974. Uptake of chlorinated paraffins and PCB from suspended olids and food by 
juvenile Atlantic salmon. Bull. Environ. ContaIn. Tox. 12:.t06-41J. 
----. 1977. The accumulation of PCB's by fish. Bull. Em'iron. Contarn. Tox. '-:285­
292. 
6
The Great Lakes Entomologist, Vol. 15, No. 1 [1982], Art. 10
https://scholar.valpo.edu/tgle/vol15/iss1/10


A New Method for Exposing Deposit Feeders to Contaminated Sediments for Food Chain Studies

Valparaiso University

The Great Lakes Entomologist Volume 15 Number 1 - Spring 1982 Number 1 - Spring 1982 Article 10 April 1982 A New Method for Exposing Deposit Feeders to Contaminated Sediments for Food Chain Studies Dale Roberts University of Michigan Peter G. Meier University of Michigan Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Roberts, Dale and Meier, Peter G. 1982. "A New Method for Exposing Deposit Feeders to Contaminated Sediments for Food Chain Studies," The Great Lakes Entomologist, vol 15 (1) Available at: https://scholar.valpo.edu/tgle/vol15/iss1/10 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 1982 THE GREAT LAKES ENTOMOLOGIST 59 A NEW METHOD FOR EXPOSING DEPOSIT FEEDERS TO CONTAMINATED SEDIMENTS FOR FOOD CHAIN STUDIES Dale Roberts and Peter G. Meier l The ubiquity and refractory nature of certain organic compounds, such as chlorinated pesticides and polychlorinated biphenyls (PCB's), results in their accumulation in aquatic sediments <Holdrinet et al. 1978, Peck et al. 1980, Wang et al. 1979). Their continuous release from this reservoir through physico-chemical and biogenic processes to the over­lying water column results in the accumulation of xenobiotic compounds n the food chain. Accumulation of organics within organisms can be accomplished through several routes. Direct uptake from water across gill and membrane surfaces bas been suggested by some as the main mechanism (Nisbet and Sarofim 1972, Fowler et al. 1978). Others have shown that the accumulation by aquatic invertebrates and fish is a two step process: desorption from sediments into water and uptake from water by the biota (Halter and Johnson 1977). Recent studies have documented the importance of direct uptake of organics by sediment-ingesting benthos (Fowler et al. 1978, Langston 1978, Meier and Rediske 1979). However, contro­versy still exists as to the role water and/or sediment concentrations play regarding accumu­lation and biomagnification of these compounds in food chains. In examining the uptake and behavior of organics in food chain organisms, it is important to expose test animals in such a manner that the results are reproducible, statistically significant, and applicable to natural systems. Several methods have been described in the literature. Researchers who exposed algae and/or invertebrates to contaminated water failed to consider the role of sediments in studies concerning low water soluble compounds. Often these exposures are made at artificially high concentrations of test material in water (Hattula and Karlog 1973, Melancon and Lech 1976, Sandlers and Chandler 1972). In other food chain studies, test animals were fed a contaminated synthetic processed food which did not simulate natural conditions (Zitko 1974, 1977; Hanson et al 1976; Narborne 1979). The purpose of the study was to develop a method that would aid in food chain studies by providing: (I) A predictive capability through manipulation of the biomass-sediment ratio to achieve the desired body burden in the food organism; (2) A large number of sediment associated organisms with similar body burdens; (3) An application in a variety of situations with different substances and test organisms; and (4) Repro ucible results. MATERIALS AND METHODS Test organisms were larvae of Chironomus plumosus Meigen (Diptera: Chironomidae) collected from oxidation lagoons in Fowlerville, Michigan. These midges were maintained in 38-liter aquaria according to the method described by Meier and Torres (1978) (Fig. I). The numerous egg masses obtained from the adults of the wild collection served as the-starting material for the laboratory culture. Background concentration of PCB's in the midges was insignificant at an analytical level of <0.05 jJ.g/g wet weight. The polychlorinated biphenyl used in this study was 14C labeled 2,4,5,2' ,4',5' hexa­chlorobiphenyl packaged in crystalline form at 1.5 mg per vial. 2 The content was dissolved with 15 ml of acetone and then diluted with distilled water to a concentration of 0.1 mg/ml. This stock solution was added in specific volumes to each of the in ubation vessels for the desired concentration, 1 Department of Environmental and Industrial Health, School of Public Health, The University of Michigan, Ann Arbor, MI 48109. 2Source: California Bionuclear Corporation; Specific Gravity: (mCi/I11i\.!.)24; Activity per vial: 0.1 mCi. 1Roberts and Meier: A New Method for Exposing Deposit Feeders to Contaminated SedimenPublished by ValpoScholar, 198260 THE GREAT LAKES ENTOMOLOGIST Vol. IS, No. I Air Line (I) 	Adult Emergence Air Line "Lagoon- Water  Air Line ..::--_ Egg ~Masses "Lagoon­. I Water Column (II) Mating and C·: ../~ Ma:~~s /7­Egg-Laying /r-substrate (III) Incubation //.-"r-Ycur.~ (IV) Maturaticr cf Yeer>; Fig. I. Schematic representation of laboratory culture of Chi onomus p!um05us. From air SOUrce Car::::r' F';!<.::!" ~ (!::~J:.. =~ ~) Bottle 001 Bottle 002 Bottle 003 Bottle 004 Bottle 005 Bottle 006 Fig. 2. Design of midge dosing chamber. The exposure apparatus for the midges consisted of six 4-liter glass chambers IFig. 2). Each vessel was sealed airtight with silicone rubber, except for an inlet and outlet. The incoming air was filtered through a carbon column which removed any potential con­taminants (i.e. oil and PCB's) from the hydraulic pump of the aeration system. The outgoing air was passed through another carbon filter to remove any PCB passing out from the chambers. For more volatile compounds, this set up can be modified with the addition of secondary butyl alcohol and potassium hydroxide trap in series behind each chamber. These compartments may then be analyzed separately and summed for obtaining a mass balance. Preliminary studies showed that midge larvae in the closed system readily and quickly accumulated sediment-associated PCB as a result of ingestion. These tests helped in de­termining the sediment to biomass ratio which most effectively and efficiently met the objectives. Hence, 25 g of paper towel (dry weight) were macerated in a blender with I liter of distilled water and poured in each chamber. An additional 2 liters of water containing the 2The Great Lakes Entomologist, Vol. 15, No. 1 [1982], Art. 10https://scholar.valpo.edu/tgle/vol15/iss1/101982 THE GREAT LAKES ENTOMOLOGIST 	 61 necessary amount of 14C labeled PCB in solution, were added to the vessels. Each was stirred by aeration for 24 h to assure even distribution of PCB and adsorption onto the macerated paper substrate. A small amount of midge food was then added (Meier and Torres 1978). After 6 h, 20 g of III and IV instar midge larvae were transferred to each chamber. The larvae rapidly settled into the sediment and started feeding o  the bacteria-enriched sediment. The flow of air to the vessels was then reduced to minimize the disturbance of the settled substrate. Each uptake experiment lasted approximately two weeks over which period the midges accumulated predictable body burdens of PCB. Food was added once every three days and the water was changed once a week. Replicate dosing chambers contained I, 10, and 100 [.Lgfg of PCB-contaminated substrate. On alternating days each vessel was analyzed for [14C] PCB in the water, in sediments, and in midges. These samples were appropriately treated and analyzed by the liquid scintillation method (Wang and Willis 1%5). A standard quench curve was generated for converting counts-per-minute to actual disintegrations-per-minute (dpm). The dpm were converted to [.Lg/g PCB by utilizing the specific activity of the labeled chlorobiphenyl. The concentration of PCB was plotted against time to generate the necessary uptake. The experiment was terminated when the midge population reached desired body burdens of 1,10, and 100 [.Lgfg. The larvae were separated from the sediments, washed, and then frozen for the food chain study (Meier and Roberts, in press). These experiments were repeated seven times to assure their reproducibility and also to obtain sufficient biomass of labeled midge larvae. Later dosings were sampled only intermittently, since dosing criteria had been established from the first experiment. RESULTS AND DISCUSSION Uptake of Sedimentary PCB by Chironomids: Preliminary Study A preliminary experiment was performed to aid in determining the dosing criteria for the midge uptake study. By examining the uptake characteristics in a saturated system (30 g midge larvae to 10 g sediments) one could design future dosings so as to best achieve the goal of producing large numbers of midge larvae with similar body burdens. In the pre­liminary study, different compartments were examined over time to determine the fate of the PCB in the dosing chamber. The results demonstrated the efficiency by midges in stripping off sedimented PCBs and incorporating them quickly (Fig. 3). The body burden of 3 [.Lgfg 10 C. p1 umosus • 4 2 11........ 	 Sediments ..-....................................... .fC---r-,----;-,---T--.-'---T'~r="'F".•=.."T............ ,......~...."" o 	 2 4 5 6 7 8 9 10 11 12 13 14 TIME OF OBSERVATION (days) Fig. 3. Preliminary study: Plot of PCB concentration in sediments and the corresponding PCB uptake by Chiranomus plumasus larvae in fLg/g wet weight. 3Roberts and Meier: A New Method for Exposing Deposit Feeders to Contaminated SedimenPublished by ValpoScholar, 198262 THE GREAT LAKES ENTOMOLOGIST Vol. 15. ::-io. I was established almost immediately. A mass balance petformed on the sediments and larvae amounted to 95% of the added PCB. The unaccounted portion was most likely either sus­pended or dissolved in the water column. As the result of this investigation. dosing param­eters for the actual uptake studies were set at 20 g larvae and 25 g contaminated sediment for each chamber. The limiting effect of sediment mass and PCB concentration a,oided drasti­cally overshooting the desired levels of the chemical in the insect as well as maximizing sediment-organism content. Uptake of Sedimentary PCB by Chironomids: Actual Stud~ Seven separate uptake experiments, each with three different concentrations. were car­ried out employing this method. The results showed that benthic organisms can accumulate significan  concent ations of PCB through direct uptake from contaminated sediments over a short time. In addition, the final concentrations of PCB at each dosing level for all experi­ments were very similar (Table I). Besides that, large numbers of labeled food organisms were prepared for food chain studies. The uptake of the radio-chemical followed first ord r rate kinetics after -lS h and showed a dose-dependent relationship between substrate concentration and body b-urden. lbe initial nonlinear portion of the uptake curve for each concentration was attrib-uted ro fiIIing the intestinal tract with contaminated sediment (Fig. 4). Some f the contaminated l.a.nae .... ere placed in clean sediments for 24 h and their body burdens were reduced. lbe procedure of facilitated removal of contaminated gut material was no  pr cticed in the actual dosing srudy since consumer· predators ingest entire organisms, including gut material. Figure 4 summarizes graphically the range of uptake concentrations in midges fiX the high 120 110 100 90 80 70 '" 60 g­50 40 30 20 10 ., :3 .­DAYS Fig. 4. Summary of sedimentary PCB uptake by Chironomus plumasllJ at a sediment concentration of 10 jJ.g/g for all experiments. 4The Great Lakes Entomologist, Vol. 15, No. 1 [1982], Art. 10https://scholar.valpo.edu/tgle/vol15/iss1/101982 THE GREAT LAKES ENTOMOLOGIST 	 63 Table 1. Summary of the final biomass concentrations of PCB in C. plumosus for the seven sets of dosings. Concentrations are given on a wet-weight basis (p.g/g). Sediment Concentration Date 1 p.g/g 10 p.g/g 100 p.g/g 15/8/79 0,1213 1.2212 12.0548 5/9/79 0.1083 1. 1321 10.5 63 24/9/79 0.0983 0.9976 10.0041 15/10/79 0.0898 0.9296 8.8714 8/11/79 0.1146 1.1869 11.3847 11/1/80 0.0866 0.8971 9.4836 25/1/80 0.1018 1.0792 1 .0616 Mean 0.1028 1.0633 10.2494 SD 0.0127 0,1217 1.3507 dosing level over time. Following the initial fast uptake, the body burdens were increasing consistently to the desired levels. The projected concentrations were reached for all levels of exposure in a two-week period for all sets of dosing. Approximately 3500 midge larvae of similar body burden and weight were obtained for each level of exposure for use in the second step uptake studies with fish. In summary, this economical method permits the researcher to manipulate the organism­sed ment atio to assure pre-determined body burdens in test organisms. I  addition, this technique is applicable in preparing large quantities of sediment ingesting organisms (natural food) that have a similar concentration for food chain studies. Finally, this method does produce reproducible results in batch experiments. LITERATURE CITED Fowler, S. W., G. G. Polikarpov, D. L. Elder, P. Parsi and J. P. Villeneuve. 1978. Poly­chlorinated biphenyls: Accumulation and contaminated sediments and water by the polychaete (Nerds diversicolor). Marine BioI. 45:265-272. Halter, M. T. and H. F. Johnson. 1977. A model system to study desorption and biological availability of PCB in hydrosoils. Aquatic Tox, Hazard Eval. Amer. Soc. Test. Mat. STP 634: 178-195. Hansen, 	L. G., W. B. Weikhorst and J. Simon. 1976. Effect of dietary Aroclor 1242 on channel catfish (lctalurus punctatus) and the selective accumulation of PCB compounds. 1. Fish. Res. Bd. Canada 133:1343-1352. Hattula, M. L. and D. Karlog. 1973. Absorption and elimination of polychlorinated bi­phenyls (PCBs) in goldfish. Acta Pharmacol. et Tox. 32:237-245. Holdrinet, M. V. H., F Frank, R. L. Thomas and L. S. Hetling. 1978. Mirex in the sediments of Lake Ontario. J. Great Lakes Res. 4:69-74. . Langston, W. 1. 1978. Accumulation of polychlorinated biphenyls in the cockle (Cerasta­derma edule) and the tellin (Macoma balthica). Marine BioI. 45:265-272. Meier, P. G. and R. Rediske. 1979. The effect of sediment oil contamination on the bio­accumulation and excretion of Arochlor 1242 by chironomid larvae. Michigan Sea Grant Program. MICHU-SG:79-207. Meier, 	P. G. and H. Torres. 1978. A modified method of rearing midges (Diptera: Chironomidae). Great Lakes Entomol. 11:89-91. Meier, P. G. and D. Roberts. The uptake and excretion of hexachlorobiphenyl in fathead minnows. (in press) 5Roberts and Meier: A New Method for Exposing Deposit Feeders to Contaminated SedimenPublished by ValpoScholar, 198264 THE GREAT LAKES ENTOMOLOGIST Vol. 15, No.1 Melancon, M. J., Jr. and J. J. Lech. 1976. Isolation and identification of a polar metabolite of tetrachlorobiphenyl from the bile f ra nbow trout exposed to 14C-tetrachlorobiphenyl. Bull. Environ. Contam. Tox. 15:181-188. Narbome, J. F. 1979. Accumulation of PCB (Phenochlor DPG) by estuarine Fish. Bull. Environ. Contam. Tox. 22:60-64. Nisbet, C. T. and A. F. Sarofim. 1972. Rates and routes of transport of PCBs in the environment. Environ. Health Perspectives. 1:21-38. Peck, D. E., D. L. Corwin and W. J. Farmen. 1980. Adsorption-desorption f Diuron by freshwater sediments. 1. Environ. Quality. 9:101-106. Sandlers, H. O. and J. H. Chandler. 1972. Biological magnification o  a polychlorinated biphenyl (Aroclor 1254) from water by aquatic invertebrates. Bull. Environ. Contam. Tox. 7:257-262. Wang, C. H. and D. L. Willis. 1%5. Radiotracer methodology in biological ;;.;;iences. Prentice-Hall, NY. Wang, T. C .• J. P Krivan, Jr. and R. S. Johnson. 1979. Residues of polychlorinated bi­phenyls and DDT in water and sediments of he St. Lucie estuary Florida. 19-. Pest. Mont. J. 13:69. Zitko, V. 1974. Uptake of chlorinated paraffins and PCB from suspended olids and food by juvenile Atlantic salmon. Bull. Environ. ContaIn. Tox. 12:.t06-41J. ----. 1977. The accumulation of PCB's by fish. Bull. Em'iron. Contarn. Tox. '-:285­292. 6The Great Lakes Entomologist, Vol. 15, No. 1 [1982], Art. 10https://scholar.valpo.edu/tgle/vol15/iss1/10

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A New Method for Exposing Deposit Feeders to Contaminated Sediments for Food Chain Studies

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