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telegraph.co.uk
Marine biologists tested 13 Brazilian sharpnose sharks from coastal waters near Rio de Janeiro and found high levels of cocaine in their muscles and livers.
The cocaine likely originated from drainage from illicit labs, excrement of drug users via untreated sewage, or less likely, from sharks feeding on bales of cocaine lost or dumped by drug smugglers.
The study, published in the journal Science of the Total Environment, indicated chronic exposure to cocaine due to human activities in Rio de Janeiro.
The researchers found cocaine concentrations up to 100 times higher than previously detected in other marine animals.
The presence of cocaine in sharks may affect their health, including potential damage to their eyesight and possibly reducing their life expectancy.