Total mercury and selenium levels in commercial shrimp along the Pacific coast of Mexico.

The present study analyzed the content of total mercury (THg) and selenium (Se) in the muscle of shrimp collected from local markets in the 11 Pacific coastal states of Mexico. Methylmercury (MeHg) concentration, Se:Hg ratio, health benefits value from selenium consumption (HBVSe) and the permissible weekly consumption were estimated to assess the health risk to consumers. All THg and Se concentrations were below the maximum permissible limits. All hazard quotient (HQ) values were <1, however in Hermosillo, Culiacán and Guadalajara, the Se:Hg ratio and HBVSe were <1 and negative, due to the low concentrations of Se. As a general conclusion, there is no risk nor benefit from the consumption of shrimp from the Pacific coast of Mexico due to its Hg and Se content.

Total Mercury and Selenium in wild Shrimp from Coastal Lagoons of Northwest Mexico: Human Health risk Assessment.

This study analyzed total mercury (THg), and selenium (Se) in edible tissues of white shrimp (Litopenaeus vannamei), blue shrimp (L. stylirostris) and brown shrimp (F. californiensis), from three states of the Northwest of Mexico in September and October 2017. Concentrations of THg and Se in the muscle were between 0.026 and 0.829 and 0.126-1.741 µg/g dry weight (dw), respectively. Significant differences were observed among Hg concentration of Sonora and Nayarit and among Se concentration of Sinaloa and Nayarit. In addition, the health risk assessment (HQ) in the three species of shrimp was between 0.550 and 0.607. All Se:Hg molar ratios were > 1 and positive HBVSe values that showed that shrimp from Northwest of Mexico does not represent a risk to human health.

Mercury and selenium biomagnification in a coastal food web from the Gulf of California influenced by agriculture and shrimp aquaculture.

The biomagnification of Hg and Se was studied using nitrogen stable isotope analysis during four seasons in a coastal lagoon of the eastern central Gulf of California. This lagoon receives agricultural, municipal, and shrimp aquaculture effluents. The species were categorized into organism groups and presented a significant accumulation of Hg and Se with respect to the sources, while the concentration of both elements in sediment and suspended particulate matter (SPM) was low. Our data confirms the positive transfers (biomagnification factors >1) of Hg and Se in the entire studied food web, and it was structured in five trophic levels across all seasons. Additionally, there were no linear correlations between the molar Se:Hg ratios and the trophic levels of the organism groups. However, the Se:Hg ratios among organism groups were >1, which indicates that there is an excess of Se and that it is not a limiting factor for the detoxification of Hg.