Mercury contamination in Gulf of Mexico fish

Abstract

Mercury is a toxic, naturally occurring element that is hazardous to humans at high concentrations. Natural sources include degassing of the earth and volcanic activities; however human-related activities contributing to atmospheric levels such as industrial waste disposal, chlor-alkali plants and fossil fuel combustion have increased three fold since 1900. Once mercury enters marine systems it can be converted by microbes to its most toxic form - methyl mercury (MeHg). Methyl mercury is a neurotoxin and poses a great risk to human health; it is especially dangerous to pregnant women and developing children. MeHg accumulates from small benthic invertebrates to large pelagic fish; thus it reaches the human population and other terminal predators such as marine mammals through fish consumption. Mercury concentrations were measured in eight Gulf of Mexico fish pelagic fish species using a DMA 80 analyzer in order to determine mercury accumulation rates in different species. Total mercury concentration ranged from 0.035 to 12.11ppm and increased with increasing length (and thus age) of the fish. Highest measured was 12.1 ppm in Wahoo (Acanthocybium solandri). Blackfin tuna (Thunnus atlanticus) and yellowfin tuna (Thunnus albacores) had moderate mercury concentrations (1.4 and 1.3 ppm). Dolphinfish (Coryphaena hippurus) and vermilion snapper (Rhomboplites aurorubens) had lowest concentrations (<1ppm). Knowledge of mercury transfer in food webs is essential to ensure protection of the environment and human health. This project is supported by the Qatar National Research Fund (QNRF) through the Environmental Studies Center of Qatar University, Doha.