Impact of dredging on the physicochemical parameters of water in the estuary of Sebou river (Morocco)

Author(s): M.Izougarhane, I.El Harrak, K.Houri, H.El Ibaoui, S.Chakiri, A.Essamri, M.Fadli

For ports, the dredging is an operation that allows the removal of debris, including the sand, clogging the navigation channels. For sands, because of the shortage of this product very used in the Buildings and Public Works, this activity is booming in Morocco. Furthermore, it is recognized that sediment dredging and their disposal at sea is a pathway of contamination of the marine environment. The present work concerns the study of some physico-chemical parameters and concentrations of heavy metals from the waters of the estuary of a major river ofMorocco, the Sebou, just after a first dredging operation. The results showed that these waters are highly polluted. This pollution is manifested by an increase in the values of indicators of pollution (COD, BOD5, TSS, conductivity, ammonium, nitrate and ortho-phosphate). The values often exceed those found by other authors just before the installing of the Operating Company of sea, sand at the estuary especially those of Ed-Darouich realized in 2006. These values often exceed the recommended standard thresholds by the draft Moroccan surface water quality. For the heavy metals, particularly chromium, copper and lead concentrations in surface water the values are lowand do not pose a risk of contamination. So, the dredgingmust be done within a framework of integratedmanagement, taking into account the ecological balance of the coastal zone as a whole.

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