Using passive sampling and zebrafish to identify developmental toxicants in complex mixtures

Abstract

Using effects-directed analysis, we investigated associations previously observed between polycyclic aromatic hydrocarbons (PAHs) and embryotoxicity in field-deployed low-density polyethylene (LDPE). We conducted effects-directed analysis using a zebrafish embryo assay and iterative fractionation of extracts of LDPE that were deployed in the Portland Harbor superfund megasite, Oregon (USA). Whole extracts induced toxicity including mortality, edema, and notochord distortion at 20% effect concentration (EC20) values 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 other substances 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 found chromatographic evidence that dithiocarbamates are responsible for notochord and other sublethal effects, although exact matches were not obtained. Fatty acids and dithiocarbamates were previously unrecorded components of LDPE extracts and likely contribute to the toxicity of the whole mixture. The present study demonstrates the success of effects-directed analysis in nontargeted 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 effects-directed analysis to combine LDPE and zebrafish, approaches that are widely applicable to identifying developmental hazards in the bioavailable fraction of hydrophobic organic compounds. Environ Toxicol Chem 2017;36:2290-2298. © 2017 SETAC.

Development of quantitative screen for 1550 chemicals with GC-MS

“…Epidemiology studies may bin chemistry results into just a few groups [ 25 ], and human health risk assessment may assume uncertainty factors of 100 when calculating reference doses [ 26 ]. The silicone wristband PSDs used as examples in the present study commonly accumulate concentrations that range several orders of magnitude, much greater than the precision of the MASV1500 method [ 17 , 20 ].…”

“…The MASV1500 method described here is a targeted analysis for a large number of chemicals that can be used effectively in conjunction with non-targeted methods or sample fractionation [ 17 , 29 ]. Quantitation using AMDIS and a predictive model for response factor was able to quantify multiple classes of chemicals in representative samples within a factor of 2.5, better than comparable methods that have been previously reported.…”

“…Typical samples that we anticipate analyzing with the method described in this paper include biological tissue extracts [ 14 ], LDPE passive sampling device extracts deployed in river water [ 17 ], and silicone wristbands that were worn by people [ 15 , 18 ]. We evaluated the detection rate and quantitative accuracy and precision of 112 chemicals added to samples representative of typical background matrices.…”

“…Both pre- and post-SPE-cleaned wristband samples were evaluated. We also tested the overspike solution in one crayfish extract [ 14 ], one pre-deployment LDPE, one pre-deployment wristband, and four deployed LDPE [ 17 ].…”

An integrative approach combining passive sampling, bioassays, and effect‐directed analysis to assess the impact of wastewater effluent

“…Knowing that this WWTP effluent discharge is from municipal sources (i.e., households and industries), a diverse group of micropollutants is potentially responsible for such lethal and sublethal developmental effects. By using effect‐directed analysis based on in vivo zebrafish embryotoxicity assays, recent studies successfully identified teratogens in complex matrices (Legler et al ; Bergmann et al ). Such approaches (i.e., using in vivo teratogenic effect‐directed analysis) could be used to attempt to identify the compounds responsible for the observed developmental toxicity effects in the present study.…”