| Popis: |
We studied the contamination by organochlorine insecticides of the clams and eels in Moulay Bousselham lagoon, on the west coast of Morocco. DDT and its metabolites, DDE and DDD, were found to have accumulated in the lipids of all specimens. Organochlorine concentration in clams was highest for samples taken from the mouth of channels draining agricultural land. Organochlorine content was more than 100 ng/g in some cases in this area, whereas it was less than 40 ng/g in the rest of the lagoon. Organochlorine content peaked in May and then decreased after egg laying. Marked concentration of these pesticides was observed in eels, which are mobile and carnivorous. Organochlorine content peaked in November, mainly among the large specimens preparing to migrate to the ocean. DDT was stored in lipids, at concentrations up to 2,000 ng/g. However, even this high concentration is below the upper limit for human consumption. The higher proportion of DDE than of DDT shows that most of the contamination is not recent. BHC and cyclodienes were also detected, at low concentrations. The contamination of eels and clams in the Moulay Bouselham does not currently pose a threat to public health. |
