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Sensitivity of species to chemicals: dose-response characteristics for various test types (coldbloodedLC50, cold-blooded LR50 and warm-blooded LD50) and modes of action
Citation:
Hendricks, J., J. Awkerman, D. de Zwart, AND M. Huijbregts. Sensitivity of species to chemicals: dose-response characteristics for various test types (coldbloodedLC50, cold-blooded LR50 and warm-blooded LD50) and modes of action. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY. Elsevier Science Ltd, New York, NY, 97:10-16, (2013).
Impact/Purpose:
To identify similarities and differences in contaminant levels affecting cold-blooded and warm-blooded species administered via different routes, data on lethal water concentrations LC50, tissue residues LR50 and oral doses LD50 were collected from databases, each representing the largest in its kind.
Description:
While sensitivity of model species to common toxicants has been addressed, a systematic analysis of inter-species variability for different test types, modes of action and species is as yet lacking. Hence, the aim of the present study was to identify similarities and differences in contaminant levels affecting cold-blooded and warm-blooded species administered via different routes. To that end, data on lethal water concentrations LC50, tissue residues LR50 and oral doses LD50 were collected from databases, each representing the largest in its kind. LC50 data were multiplied by the bioconcentration factor (BCF) to convert them to internal concentrations that allow for comparison. For each set, we combined levels lethal to different species by calculating the mean and standard deviation per compound. Next, the means and standard deviations were averaged per mode of action. Both the means and standard deviations calculated depended on the number of species tested, which is at odds with quality standard setting procedures. Means calculated from (BCF)LC50, LR50 and LD50 were largely similar, suggesting that different administration routes roughly yield similar internal levels. Levels for compounds interfering biochemically with elementary life processes were about one order of magnitude below that of narcotics disturbing membranes. Neurotoxic pesticides and dioxins induced death in even lower amounts. Standard deviations for LD50 data were similar across modes of action, while variability of LC50 values was lower for narcotics that for substances with a specific mode of action. The study indicates several directions to go for efficient use of available data in risk assessment and reduction of species testing.
