Bioaccumulation of cd and hg in Muscle of Juvenile Pacific Sharpnose Shark Rhizoprionodon longurio from the SE Gulf of California.

In this study, the concentrations of Cd and Hg were measured in muscle of juvenile individuals at an importan fishing ground in southeastern Gulf of California to assess the health risk to human consumers considering elemental levels and rate of shark consumption in NW Mexico. Twenty-eight individuals were sampled in September 2019. Quantification of Hg was made by cold vapor-atomic absorption spectrophotometry, analyses of Cd were made by graphite furnace atomic absorption spectrophotometry. In general, average Hg (1.27 µg g-1 dry weight) concentrations were higher than Cd (0.059). In comparison to results of Cd and Hg in muscle of several species of genus Rhizoprionodon sp., our reported concentrations were comparable. Maximum permissible limits (Cd 0.5 and Hg 0.5 µg g-1 wet weight) in fish products for human consumption were not exceeded. Health risk assessment to shark consumers indicated that Hg is of more concern than Cd but no hazards exist.

Differential Tissue Accumulation of Copper, Iron, and Zinc in Bycatch Fish from the Mexican Pacific.

In order to ascertain if Cu, Fe, and Zn are differentially accumulated in fish tissues, metal concentrations were measured in the muscle and liver of bycatch fish from the states of Sinaloa (189 specimens, 7 species) and Guerrero (152 individuals, 8 species) in the Mexican Pacific Coast during March and November 2011. Additionally, metal levels were compared with the maximum allowable limits set by international legislation and contrasted with similar ichthyofauna from other regions. Liver had more elevated concentrations of Cu (Sinaloa 28.3, Guerrero 16.3 µg g-1), Fe (Sinaloa 1098, Guerrero 636 µg g-1), and Zn (Sinaloa 226, Guerrero 186 µg g-1) than the muscle in fish from both studied areas. The relative abundances of analyzed metals in both tissues was Fe > Zn > Cu. As far as limits set by international legislation (Australia, India, New Zealand, Zambia), measured concentrations of Cu in the edible portion of fish were not found to be above the set values. In the case of Zn, the maximum allowable limits set by international legislation were exceeded by the Peruvian mojarra Diapterus peruvianus from Guerrero state (Mexican Pacific). No limits exist for Fe in the edible portion of fishery products in the national and international legislations.

Health risk assessment from mercury levels in bycatch fish species from the coasts of Guerrero, Mexico (Eastern Pacific).

With the aim of determining Hg distribution in muscle and liver of bycatch fish from Guerrero state in the Eastern Pacific Ocean and assess the potential risk to consumer, Hg was quantified in 14 species of bycatch fish. For the majority of fish the order of Hg levels was liver > muscle. The highest concentration corresponded to the liver of Isopisthus remifer (2.05 µg g(-1)) and the lowest (0.02 µg g(-1)) was detected in muscle of Prionotus sp. The highest hazard quotient (0.75) was found in the Mexican milkfish Micropogonias ectenes; considering all the individuals, mean hazard quotient was 0.336.

Cd, Cu, Pb and Zn in clams and sediments from an impacted estuary by the oil industry in the southwestern Gulf of Mexico: concentrations and bioaccumulation factors.

With the objective of estimating the temporal variation and bioavailability of Cd, Cu, Pb and Zn in Coatzacoalcos estuary, the biota-sediment accumulation factors (BSAF) were calculated. For this purpose, surficial sediments and clams from 14 selected sites were collected during three climatic seasons. In surficial sediments, highest levels of Cd and Cu were measured during the rainy season near to the industrial area of Minatitlan, while highest concentrations of Pb and Zn were registered during the windy season in sediments collected near to the industrial area of Coatzacoalcos. Considering all the sampling seasons and bivalve species, average metal concentrations followed the order Zn > Cu > Cd > Pb. BSAF ranged from 0.01 (Pb) in Corbicula fluminea during the hot season to 25.1 (Cd) in Polymesoda caroliniana during the windy season. BSAF of Cd, Cu and Zn were higher during the windy season; in the case of Pb, the dry season was the time when such figure was more elevated. It can be stated that Polymesoda caroliniana is a net accumulator of Cd and Zn and a weak accumulator of Pb for the studied estuary.