Photoenhanced Toxicity of Weathered Crude Oil in Sediment and Water to Larval Zebrafish

Abstract

Solar radiation exposure can increase the toxicity of bioaccumulated oil compounds in a diversity of aquatic species. We investigated the photoenhanced toxicity of weathered South Louisiana crude oil in sediment and water accommodated fractions (WAF) to larval zebrafish. Larvae were first exposed for 24 h to one of six treatments: no oil (sediment or water), 7.5 g oil/kg sediment, oil-only WAF, oil WAF plus the dispersant Corexit 9500A, or dispersant alone. Larvae were then exposed to high or low levels of sunlight in control water for 3 or 3.5 h. Hydrocarbon concentrations were measured in exposure media, including alkanes, polycyclic aromatic compounds and total petroleum hydrocarbons. Significant phototoxicity was observed in larvae exposed to oiled sediment, oil-only WAF, and oil plus dispersant WAF. The results indicated that petroleum from the northern Gulf of Mexico can be phototoxic to larval fish exposed to oil in either the water column or sediment.

The Zebrafish (Danio rerio) Embryo Model as a Tool to Assess Drinking Water Treatment Efficacy for Freshwater Impacted by Crude Oil Spill

“…Two‐dimensional techniques improve analytical resolution to a certain extent, yet do not provide a comprehensive idea of matrix constituents (Coutinho et al, 2018; Melbye et al, 2009; Patterson et al, 2020; Striebich et al, 2014). Therefore, researchers have traditionally studied either individual or groups of target compounds for quantification, or have conducted nonspecific TPH fingerprinting for qualitative analysis indicative of the potential for human exposure and toxicity outcomes (Barron et al, 2018; Kristanto, 2012).…”

“…Identifying candidate hydrocarbons and byproducts may not be the most productive route to determining the toxicity of samples contaminated by a crude oil spill, because the analytical characterization is not only time and resource intensive, but often the target chemical analytes may not necessarily be the most toxic in the mixture. For instance, polar photo‐oxidation intermediates and products generated from oil hydrocarbons such as phenols, acids, and carbonyls may contribute to the overall toxicity potential (Barron et al, 2018; Maki et al, 2001) but are not always targeted in analyses. Furthermore, known and unknown soluble hydrocarbons that are toxic at levels below the method or instrumental detection limits are easily overlooked.…”