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Evaluation of alternative reference toxicants for use in the earthworm toxicity test
Author(s) -
Yeardley Roger B.,
Lazorchak James M.,
Pence Michael A.
Publication year - 1995
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620140710
Subject(s) - toxicant , environmental chemistry , chemistry , toxicology , chloride , health hazard , reproducibility , potassium , toxicity , chromatography , biology , environmental health , medicine , organic chemistry
The use of the 14‐d earthworm toxicity test to aid in the evaluation of the ecological impact of contaminated soils is becoming increasingly widespread. However, the method is in need of further standardization. As part of this continuing process, the choice of reference toxicants was evaluated. Reference toxicants were rated in relation to the following criteria: (a) reproducibility, (b) low human health hazard, (c) feasibility of measurement, and (d) chemical stability. Potassium chloride (KCl) and ammonium chloride (NH 4 Cl) were evaluated as possible alternatives to the one currently in common use, 2‐chloroacetamide. Potassium chloride rated the best for the combination of the four criteria, followed by NH 4 Cl and 2‐chloroacetamide. Coefficients of variation (C.V.s) from control charts of six definitive tests were used to measure reproducibility. The best reproducibility (lowest C.V.) was shown by KCl, followed by NH 4 Cl and 2‐chloroacetamide. Toxicants ranked KCl < NH 4 Cl ≪ 2‐chloroacetamide in terms of health hazard; and KCl = NH 4 Cl > 2‐chloroacetamide in terms of measurement feasibility. Both 2‐chloroacetamide and NH 4 Cl changed in concentration during testing. Evidence is also presented that 2‐chloroacetamide degrades rapidly during testing, and that, as dead worms decay, ammonification may be adding another toxicant, ammonia, to tests.