High levels of mercury discovered in sharks
High mercury levels which surpass the allowable levels were discovered by Universidad Nacional de Colombia (UNal) researchers after taking several tissue samples on sharks.Bogotá D. C., 08 de junio de 2016 — Agencia de Noticias UN-
The research project, part of a master’s degree program, includes analysis on three groups of samples.
The analyses were carried out on sharks caught in waters of the Provinces of La Guajira, Atlántico and Córdoba.
After receiving the accusations, the Office of the Comptroller General followed up the case and found traces of elements such as mercury, zinc and copper.
“Analyses show amounts greater than a thousand micrograms of organic mercury (methylmercury) per kilogram of fish, an amount which technically is above the allowable levels for a fish,” said Natural Resources PhD and UNal Professor Néstor Campos.
This type of elements, although a natural constituent of the Earth’s crust, are not produced or broken down by human beings.
The analysis were carried out on samples of 5 small sharks (approximately 1 meter long) caught by artisanal fishermen in waters off the Province of La Guajira, near an area called Las Flores near Barranquilla and Isla Fuerte, between the Provinces of Córdoba and Sucre.
The samples were dried, pulverized and treated with acid to dissolve the organic matter in order to take the appropriate readings.
Furthermore they analyzed the organic mercury in stomach remains in order to compare the amount of mercury in the food taken by the sharks with the trace amounts in the tissue. The resulting amount is known as biomagnification, which shows how much the concentration of mercury is multiplied from one level to the next.
The research project is part of a master’s degree thesis which hopes to establish which is the role of sharks in methylmercury metabolism in the coastal systems of the country. Metabolism is key because it is a process which turns inorganic into organic mercury.
In fact this substance can have several toxicity forms of which the organic is probably the most dangerous, as it accumulates in fat tissue and can inclusively reach nervous tissue.
Although this is only the first sample, the research project includes analyzing two additional sampling periods: the findings turn into a first indication of the issue announced by the Office of the Comptroller General of Colombia around the alleged impact due to presence of mercury, zinc and copper in the Bay of Cartagena.
Although the control organism says there is still no bodily deformations of animal species, including humans, despite claims from a citizen that 50 people had been impacted; it still says there are indications of contaminating substances which eventually may turn into a health threat from these communities.
The evidence suggests that in the case of Cartagena, residue with these elements is directly linked to removal of sediments from local dredging operations.
“Is it key to compare these results with data from international environmental agencies from United States, Brazil or the World Health Organization, to establish the seriousness of the concentration of methylmercury,” said Campos.(Por: Fin/HEVC/MLA/JAAH