Occurrence of organochlorine pesticides in stream sediments from an industrial area.

Contaminated stream sediments are a serious problem because contaminant residues will be persistent for a long time. Organochlorine pesticides (OCPs) were screened in stream sediments collected along stream flows close to an industrial area in northwestern Spain. Analyses were performed by extraction with organic solvents followed by gas chromatography-mass spectrometry detection. OCPs such as hexachlorobenzene, hexachlorocyclohexane (alpha and beta isomers) and DDT were detected at levels ranging between 29 and 392 microg/kg indicating there is a moderate to severe pollution in the area even though they were banned a few decades ago.