Ecotoxicological assessment of pyrethroid toxicity to Caenorhabditis elegans

Abstract:

To determine the toxicity of chemicals in the environment, toxicologists use tiered toxicity testing featuring various model organisms. Historically predictions concerning mammalian toxicity were supported using rats or mice as models, but these species are being phased out by regulatory agencies (ex: US EPA). This presents a new challenge: toxicologists need to find alternative models that are informative for mammalian risk assessment. The goal of this research is to determine the appropriateness of Caenorhabditis elegans as a possible alternative for mammalian toxicity testing. This project consisted of several toxicity tests, exposing C. elegans to multiple pyrethroid insecticides: bifenthrin, cypermethrin, permethrin, deltamethrin, and esfenvalerate. Two strains of C. elegans will be tested: DC19 (hyper-sensitive) and N2 (wildtype). Once the worms had been exposed for 24 hours, they were observed for mortality and the data were used to calculate the median lethal concentration (LC₅₀) of each compound. These LC₅₀s were ranked by toxicity and compared to those of traditional mammalian models. This research could support the use of C. elegans as an alternative model for ecotoxicology.