Contamination des eaux souterraines par le lixiviat des décharges publiques : Cas de la nappe phréatique R’Mel (Province de Larache - Maroc Nord-Occidental)

La percolation du lixiviat en provenance des dechets des decharges constitue une source de pollution des ressources en eau souterraine par infiltration, constituant ainsi une menace aussi importante que celle liee al'accentuation du deficit hydrique. La decharge publique de Larache constitue un modele type de deterioration des ressources en eaux par un effet de contamination du lixiviat en provenance de la decharge et des pratiques agricoles. Les mesures realisees sur le lixiviat et sur les eaux prelevees des puits situes autour de la decharge et ayant porte sur les parametres physicochimiques, de pollution (O2 dissous, DCOc), de metaux lourds et sur des analyses bacteriologiques, permettent de qualifier le lixiviat comme une source de contamination a potentiel anoxique et reducteur. La charge polluante est importante et se traduit par des valeurs de DCO et dfazote kjeldahl elevees (63375 mg/l et de 798 mg/l). Les resultats permettent aussi de conclure sur la qualite mediocre des eaux contenues dans les poches souterraines notamment pendant la periode seche, ce qui est illustree par les valeurs elevees en certains metaux (Pb (800 ƒÊg/l), Cd (40 ƒÊg/l), Cr (80 ƒÊg/l) et Fe (650 mg/l)), en coliformes totaux, en coliformes fecaux et en streptocoques fecaux

Assessment of metal pollution in the river of Martil emerging in the western Moroccan Mediterranean. Mobility and impact of human activities

This study is part of a monitoring of the evolution of variations in time and space contents of metallic elements of surface waters of the river of Martil between two sampling campaigns (May 2010 and May 2011). The comparison of the results of metal analyzes of the two campaigns show different variations of the contents of metallic elements. The magnesium content increased almost 10 times, which highlights the intensity of activities that caused this increase for one year only. The concentrations of nickel and lead fell below standards and indicate a water medium to high quality, as the concentrations of aluminum, zinc and copper, which have been reduced compared to the 2010 campaign and are still very low and do not pose a threat so large. The concentration of cadmium also decreased slightly but remains high above the standard set which is 5 mg / l, which raises some concern about this element and its possible sources. For iron, its concentration was doubled, which is why it is a beginning of water contamination because the recorded values are between 1 and 2, indicating an average water quality

Assessment of metal pollution in the river of Martil emerging in the western Moroccan Mediterranean. Mobility and impact of human activities

This study is part of a monitoring of the evolution of variations in time and space contents of metallic elements of surface waters of the river of Martil between two sampling campaigns (May 2010 and May 2011). The comparison of the results of metal analyzes of the two campaigns show different variations of the contents of metallic elements. The magnesium content increased almost 10 times, which highlights the intensity of activities that caused this increase for one year only. The concentrations of nickel and lead fell below standards and indicate a water medium to high quality, as the concentrations of aluminum, zinc and copper, which have been reduced compared to the 2010 campaign and are still very low and do not pose a threat so large. The concentration of cadmium also decreased slightly but remains high above the standard set which is 5 mg / l, which raises some concern about this element and its possible sources. For iron, its concentration was doubled, which is why it is a beginning of water contamination because the recorded values are between 1 and 2, indicating an average water quality

Contamination and depuration of Paralytic Shellfish Poisoning by Acanthocardia tuberculata cockles and Callista chione clams in Moroccan waters

International audienceThis study of Gymnodinium catenatum was conducted across two sampling stations; M'diq bay and Oued Laou estuary during the period from July 2007 to May 2009. Gymnodinium catenatum blooms occurred after a rainfall event in autumn and early winter. Statically analyses showed a positive correlation with rainfall. During January 2008, the G. catenatum bloom resulted in contamination of tuberculate cockles and sweet clam by Paralytic Shellfish Poisoning (PSP) toxins. In the Oued Laou estuary, the levels of these toxins in shellfish went beyond the normative threshold for consumption of shellfish, (80 µg SXTeq. /100g of meat) and reached (710 ± 82.07) and (198 ± 6.56) µg SXTeq. /100g of meat in cockles and sweet clam respectively. In M'diq bay, concentrations of PSP toxins in the meat of these two shellfish were lower (256.57 ± 12.22 µg SXTeq. /100g and 80.66 ± 8.14 µg SXTeq. /100g of meat in tuberculate cockles and sweet clam respectively. An experimental test of depuration of tuberculate cockles and sweet clam contaminated by the PSP toxins was conducted in laboratory conditions in the first week of January 2008. The results showed partial and progressive elimination of PSP toxins in two shellfish species over time. In the tuberculate cockle, the elimination of PSP appears to be slower compared with the sweet clam; it took 120 days to reach levels of 80 µg SXTeq. /100g of meat, on the other hand only 3 days were needed to reach this safe concentration in the sweet clam