Mercury levels in fish in the Valencian Community: temporal evolution (2011-2017) and associated factors

BACKGROUND // Mercury (Hg) is a toxic metal, and dietary exposure is the main one in humans, especially fish consumption. In order to reduce Hg exposure, maximum levels in fish products have been established. We aimed to describe total mercury (THg) and methylmercury (MeHg) concentrations in fish species consumed in Comunitat Valenciana, as well as factors associated and their tendency during the period 2011-2017. METHODS // A retrospective descriptive study of Hg levels in fish meat samples in Comunitat Valenciana between 2011 and 2017 and their temporal trend was carried out, both in general and by fish groups. Data comes from Generalitat Valenciana’s Health Surveillance of Food Program. We created multivariate linear regression models to evaluate the association between sampling year, fish group and origin and THg (n=560) / MeHg (n=206) concentrations. The average annual trend of THg and MeHg levels throughout the period was evaluated. RESULTS // The median was 0.20 mg/kg for THg and 0.14 mg/kg for MeHg. Swordfish, fresh tuna/albacore and canned tuna, in that order, showed the highest concentrations. Global tendency of THg levels was descending when adjusting by swordfish annual percentage. When we analized the tendency in swordfish, we observed a 7% decrease on average per year. CONCLUSIONS // Global temporal trend of THg levels in fish in Comunitat Valenciana during the period 2011-2017 is descending after adjusting by the relative weight of swordfish over the total number of samples by year. We observe a descending tendency when studied by species (swordfish).