Bergmann, A.J., Tanguay, R.L., Anderson, K.A. (2017) Using passive sampling and zebrafish to identify developmental toxicants in complex mixtures. Environmental toxicology and chemistry. 36(9):2290-2298.
Using effects-directed analysis (EDA), we investigate associations previously observed between PAHs and embryotoxicity in field-deployed low-density polyethylene (LDPE). We conducted EDA using a zebrafish embryo assay and iterative fractionation of extracts of LDPE that were deployed in Portland Harbor Superfund Megasite, Oregon. Whole extracts induced toxicity including mortality, edema, and notochord distortion at EC20s of approximately 100, 100, and 10 mg LDPE/mL, respectively. Through fractionation, we determined that PAHs at concentrations similar to previous research did not contribute markedly to toxicity. We also eliminated pesticides, phthalates, musks, and others identified in toxic fractions by testing surrogate mixtures. We identified free fatty acids as lethal components of LDPE extracts and confirmed their toxicity with authentic standards. We have chromatographic evidence that dithiocarbamates are responsible for notochord and other sub-lethal effects, although exact matches have not been obtained. Fatty acids and dithiocarbamates were previously unrecorded components of LDPE extracts and are likely contributing to the toxicity of the whole mixture. This work demonstrates the success of EDA in non-targeted hazard identification using the zebrafish embryo test as a self-contained battery of bioassays that allows identification of multiple chemicals with different modes of action. This is the first EDA to combine LDPE and zebrafish, approaches that are widely applicable to identifying developmental hazards in the bioavailable fraction of hydrophobic organic compounds. This article is protected by copyright. All rights reserved.