Study of the spatial and temporal variation of physical-chemical parameters characterizing the quality of surface waters of the lagoon Marchica - North-East Morocco

The study concerns the analysis of physical-chemical parameters (temperature: t°,ph,electrical conductivity: e.c.,dissolved oxygen: do,orthophosphate: po4 2-,nitrate: no3 - and nitrite: no2 -) of the nador lagoon in order to determine the effect of the new inlet on water quality of this lagoon. thereby,water samples were taken at 11 different stations of the lagoon in october 2014,january 2015,april 2015 and july 2015. our results show that the high concentration of no3 -,no2 - and po4 2-,found near the mouth of the oued selouan (station 8) was due to the terrigenous input received from that oued and to the discharge of sewage effluent from wastewater treatment plants. however,at the châala area (station 9) the high level of these nutrients could be due to caballo river input. at the kariat-arekman area,the very low dissolved oxygen concentration may be caused by the degradation of organic matter,the very low hydrodynamics and to elevated temperatures. however,the high values of electrical conductivity and salinity found in this station could be due to a high temperature found in that station which increased the evaporation rate. for the remaining areas,the values obtained do not exceed the recommended threshold of good quality water; this is due to the renewal of the water of the lagoon through the channel that communicates with the open sea. © 2017,university of mohammed premier oujda morocco.