Mercury accumulation and biomarkers of exposure in two popular recreational fishes in Hawaiian waters.

Mercury (Hg) exposure has not been examined in many recreational nearshore fish species that are commonly consumed around the Hawaiian Islands. Specific gene transcripts, such as metallothionein (MET) and thioredoxin reductase (TrxR), can be used to examine Hg exposure responses in aquatic organisms. This study measured total mercury (THg) in four species from two groups of Hawaiian nearshore fishes: giant trevally (Caranx ignobilis, n = 13), bluefin trevally (C. melampygus, n = 4), sharp jaw bonefish (Albula virgata, n = 2), and round jaw bonefish (A. glossodonta, n = 19). Total Hg accumulation and abundance profiles of MET and TrxR were evaluated for muscle, liver, and kidney tissues. Total Hg in round jaw bonefish and giant trevally tissues accumulated with length and calculated age. In round jaw bonefish tissues, mean THg was greater in kidney (1156 ng/g wet mass (wm)) than liver (339 ng/g wm) and muscle (330 ng/g wm). Giant trevally muscle (187 ng/g wm) and liver (277 ng/g wm) mean THg did not differ significantly. Fish species in this study were compared to commercial and local fish species with state and federal muscle tissue consumption advisories based on THg benchmarks developed by the U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA). Both bonefishes had mean muscle THg that exceeded benchmarks suggesting consumption advisories should be considered. MET transcript in round jaw bonefish kidney tissue and kidney THg exhibited a marginally significant positive correlation, while TrxR transcript in liver tissue negatively correlated with increasing liver THg. These results contribute to our understanding of Hg exposure associated health effects in fish.

Naturally occurring organobromine compounds (OBCs) including polybrominated dibenzo-p-dioxins in the marine sponge Hyrtios proteus from The Bahamas.

Halogenated natural products (HNPs) were identified from organic extracts of the marine sponge Hyrtios proteus from The Bahamas using gas chromatography with electron capture negative ion mass spectrometry and non-targeted gas chromatography with electron ionization mass spectrometry. The HNPs found have similar properties to anthropogenic persistent organic pollutants (POPs). Two ortho-methoxy brominated diphenyl ethers (MeO-BDEs) 2'-MeO-BDE 68 and 6-MeO-BDE 47 were the most abundant compounds. Fourteen other MeO-BDEs were detected along with several polybrominated dibenzo-p-dioxins (PBDDs) (1,3,7-triBDD, 1,3,6,8-tetraBDD and 1,3,7,9-tetraBDD) and MeO-PBDDs. Further analysis of a higher trophic level octopus (Octopus maya) from the same FAO fishing area showed that the major HNPs detected in Hyrtios proteus were also predominant. Moreover, HNPs were more than 30-fold higher in abundance than the major POPs in the octopus, i.e., polychlorinated biphenyls. Hence, Caribbean marine organisms, including those potentially used for food, harbor relatively high concentrations of HNPs.