Polycyclic aromatic hydrocarbons (PAHs), derived largely from fossil fuels and their
combustion, are pervasive contaminants in rivers, lakes, and nearshore marine habitats.
Studies after the Exxon Valdez oil spill demonstrated that fish embryos exposed to low levels
of PAHs in weathered crude oil develop a syndrome of edema and craniofacial and body
axis defects. Although mechanisms leading to these defects are poorly understood, it is
widely held that PAH toxicity is linked to aryl hydrocarbon receptor (AhR) binding and …