Development of miniaturized acute toxicity tests for Daphnia magna and Pimephales promelas
Standard EPA methods for conducting static, 48-hour, acute toxicity tests using Daphnia magna and Pimephales promelas (fathead minnows) can be miniaturized to successfully yield accurate LC50/EC50 values. The screening procedure involves exposing the test organisms to 1 mL of test solution, in test chambers which consist of the wells on 48-well microliter plates. Toxicity of the microliter plates and solvent, DO concentration, organism biomass to test solution ratio, partitioning of the chemicals and dilution of the test solution during transfer of the test organisms were examined. Survival and exposure were not significantly altered using non-standard test chambers. Toxicity of linear alkylbenzene sulfonate (LAS), pentachlorophenol (PCP), kepone, and sodium lauryl sulfate (SLS) was determined using D. magna and fathead minnows. Serial dilutions were made and 1 mL aliquots pipetted into the wells. Daphnia magna, < 24 hours old, and newly hatched fathead minnows, were transferred into the wells, twenty individuals per concentration, one per well. Dose-response curves were established for all test compounds. LC50/EC50`s values obtained using miniaturized methods strongly correlated with those obtained using standard EPA procedures. The tests were repeated a number of times with coefficient of variances for D. magna ranging from 10% with kepone to 64% with SLS. For fathead minnows CVs ranged from 0% with PCP to 23% with kepone. It was concluded that current methods can be miniaturized, yet still provide accurate information regarding toxicity for compounds in limited supply. This method may also be amenable to effluent testing i.e. TIE fractions. Other benefits include reducing the amount of equipment and space needed to conduct a test and the time involved.
- OSTI ID:
- 372508
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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