Analysis of sublethal toxicity in developing zebrafish embryos exposed to a range of petroleum substances.

The OECD 236 Fish Embryo Acute Toxicity Test guideline relies on 4 endpoints to describe exposure related effects (coagulation, lack of somite formation, tail-bud detachment from yolk-sac, and presence of heartbeat). Danio rerio (zebrafish) embryos were used to investigate these endpoints along with a number of additional sublethal effects (i.e. cardiac dysfunction, pericardial edema, yolk sac edema, tail curvature, hatch success, pericardial edema area, craniofacial malformation, swim bladder development, fin development, and heart rate) following 5 d exposures to 7 petroleum substances. The substances investigated included 2 crude oils, 3 gas oils, a diluted bitumen, and a petrochemical containing a mixture of branched alcohols. Biomimetic solid phase microextraction (BE-SPME) was used to quantify freely dissolved concentrations of test substances as the exposure metric. Results indicated that the most prevalent effects observed were pericardial and yolk sac edema, tail curvature, and lack of embryo viability. A BE-SPME threshold was determined to characterize sublethal morphological alterations that preceded embryo mortality. This work aids in the understanding of aquatic hazards of petroleum substances to developing zebrafish beyond traditional OECD 236 test endpoints and shows applicability of BE-SPME as a simple analytical tool that can be used to predict sublethal embryo toxicity. This article is protected by copyright. All rights reserved.