UGR.es - Children who eat fish more than 3 times per week show a worse performance in the general cognitive, executive and perceptual-manipulative areas of cognitive performance tests, according to a new study. Those with higher levels of exposure to mercury show a generalized delay in cognitive, memory and verbal performance. Mercury is a contaminant found especially in oily fish and canned fish and to a lesser extent in white fish. It is thought that most of the mercury contamination in fish - often higher in freshwater fish than in seafood - is directly due to mercury released into the atmosphere from decades of burning coal as fuel.

This conclusion emerges from research conducted at the University of Granada, which warns of the need to assess children’s health risk according to fish consumption, distinguishing between varieties or species they consume, especially in those areas where fish is part of the staple diet of the population.

The work entitled “Children’s exposure to environmental contaminants in Granada and potential effects on health” was carried out by Carmen Freire Warden, from the Department of Radiology and Physical Medicine of the UGR, and led by professors Nicolás Olea and Marieta Fernández Serrano Cabrera.

For this study, scientists analyzed the exposure to environmental contaminants through water, air and diet, in a sample of 220 children in the geographic health care area of San Cecilio University Hospital in Granada. This study has described for the first time the extent of childhood exposure to environmental pollutants of special concern, such as trihalomethanes, NO2, polycyclic aromatic hydrocarbons and mercury. Following the hypotheses posed, this research assessed the combination of exposure to air pollution, on the one hand, and mercury, on the other, with child neurodevelopment at 4 years of age.

Mercury concentrations in children

Thus, total mercury concentrations found in the hair of 4 year-old-children from Granada were between 0.04 and 6.67 g / g. Concentrations were higher than those found in other pediatric populations with a lower consumption of fish, but lower than levels found in high consuming areas.

Important factors in this exposure were the place of residence, maternal age, passive exposure to tobacco smoke and consumption of oily fish. The results suggest that fish consumption is the main source of exposure to mercury in the sample population studied.

In contrast, studies of fish oil supplements have not found any appreciable mercury levels in fish oil capsules.