Assessment of certain organochlorine pesticide and polychlorinated biphenyls in sediments - upstream part of sebou river - morocco

The main purpose of this work was to investigate for the first time, levels of certain organochlorine pesticides and polychlorinated biphenyls in Sebou river sediments in its upper part. Three sampling campaigns were carried out in three years between October 2018 and October 2020 in six sampling locations of the river. The results of our investigations have showed that the sediments contains more or less pollutants depending on the sampling area. The downstream part of the studied area is more loaded with OCPs and PCBs than the upstream part. HCH and DDT isomers were two dominant pollutants of OCPs in this region. Levels of ∑3HCHs were ranging from 0.56 to 3.87 ±0.15 ppb and ∑3DDTs concentrations ranging from 0.96 to 5.30 ±0.10 ppb. For individual HCHs, α-HCH registered the highest value of 2.31 ppb, and β-HCH was the most dominant isomer in all stations, and p,p’-DDT was the most dominant with 2.61 ppb. The concentrations of ∑5PCBs in sediment samples were between 1.91 and 6.53 ±0.20 ppb. The maximum levels of these pollutants were recorded in the sediments sampled from Allal El Fassi dam. The presence of these molecules could be directly related to the use of pesticide upstream and to aerial deposition due to their global movement.