Distribution of organochlorine pesticides in surface water and sediments in Lake Volvi (northern Greece)

The objective of the study was to monitor the occurrence of a wide range of OCPs and sediments of the Lake Volvi in northern Greece and to determine their temporal and spatial variations. The samples have been collected seasonally for a period of one year. Solid-phase extraction followed by gas-chromatographic techniques with electron-capture detection was used for the determination of the compounds. The compounds detected were HCB, lindane, beta-HCH, heptachlor, methoxychlor, alpha-endosulphan, and 2,4-DDT, while alpha-HCH, aldrin, heptachlorperoxide, 4,4-DDE, dieldrin, endrin, 4,4-DDD, beta-endosulphan,and 4,4-DDT could not be observed ( detection limits >= 1 ng L-1). The frequencies of the compounds detected in the samples varied between 10 and 83% and between 6 and 88% in the water and sediment samples, respectively. Among the 16 OCPs pesticides monitored, only 2,4-DDT and methoxychlor were found in detectable concentrations in sediments throughout the whole sampling period. The water-sediment distribution pattern of the detected compounds reflects the great capacity of the lake sediments to adsorb and accumulate such compounds.