A team of researchers from the University of Cadiz has confirmed that zinc, copper and lead are present at high levels in the water and sediments of the Huelva estuary, and have studied how some of these heavy metals are transferred to fish. The study shows that zinc, cadmium and copper accumulate in the body tissues of sole and gilthead bream.
"We found positive correlations between the levels of some metals in the waters of the Huelva estuary and those in the tissues of gilthead bream (Sparus aurata) and sole (Solea senegalensis)", M Dolores Galindo, a professor of Analytical Chemistry at the University of Cadiz and the head of the study published recently in the Journal of Hazardous Materials, tells SINC.
The researchers focused their analysis on the "bioavailabilty" of heavy metals in coastal waters and their impact on commercially important species, such as the two studied. The results showed elevated levels of zinc, copper and lead, both in water and sediment, although the most "available" elements for the fish were zinc, cadmium and copper.
"Numerous laboratory studies have looked at the effects of pollutants on aquatic organisms, but our research observes this phenomenon in the natural environment, in one of the few estuaries in Spain with high levels of metals contamination", says Galindo. The Huelva estuary and the Tinto and Odiel rivers which flow into it are all affected by discharges from industries and historic mining activities locally. The area, in which fishing is forbidden, is globally significant in terms of its levels of heavy metal contamination.
For this reason it is an ideal area for scientists in which to examine the effects of contaminants on the environment. The researchers, who are working on developing environmental quality criteria, studied the levels of copper, cadmium, lead and arsenic on three types of samples water, sediments and fish tissue.
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FECYT - Spanish Foundation for Science and Technology