Eels and Nose Candy

An interesting study from Naples has demonstrated that the tiny concentrations of cocaine derivatives that contaminate river waters from drug users (especially near big cities in Italy and England), seem likely to severely impair the ability of European eels to undertake their long reproductive migrations between  the sea and freshwater (https://www.theguardian.com/environment/2018/jun/21/cocaine-in-rivers-harming-endangered-eels-study-finds). The drug alters the activity of the fish and also damages its musculature and its fat stores (needed to power the migration). Even 'rehabilitating' the eels in clean water for several days, failed to restore the fish's condition. This is yet another example of a detrimental effect of humans on other animals but who would have considered such a link likely?