Environmental News Network

Fluorescence method detects mercury contamination in fish

Researchers from the University of Burgos (Spain) have developed a fluorescent polymer that lights up in contact with mercury that may be present in fish. High levels of the metal were detected in samples of swordfish and tuna. According to the conclusions of another Spanish study, mercury exposure is linked to reduced foetal and placental growth in pregnant women.

The presence of the toxic metal mercury in the environment comes from natural sources, however, in the last decades industrial waste has caused an increase in concentrations of the metal in some areas of the sea. In the food chain, mercury can be diluted either in organic form as methylmercury (MeHg+) or as an inorganic salt, the cation Hg2+.

Selenium deficiency promoted by climate change

As a result of climate change, concentrations of the trace element selenium in soils are likely to decrease. Because the selenium content of crops may also be reduced, the risk of selenium deficiency could be increased in many regions of the world. This was shown by a recent study which used data-mining to model the global distribution of selenium.

Selenium is an essential micronutrient obtained from dietary sources such as cereals. The selenium content of foodstuffs largely depends on concentrations in the soil: previous studies have shown that low selenium concentrations are associated with high pH and oxygen availability and low clay and soil organic carbon content. In Europe, as is known from regional studies, selenium-poor soils are found particularly in Germany, Denmark, Scotland, Finland and certain Balkan countries.