Assessment of spatial and seasonal nitrate variation of groundwater in the irrigated perimeter (Tadla plain-Morocco)

Abstract

The Nitric pollution in the groundwater of the Tadla plain increases the risk of degrading the quality of water resources and creates a risk to human health and the environment. This study aims to establish the state of pollution of the groundwater by nitrates in Béni Aamir and Béni Moussa aquifers, to follow its temporal evolution and to map its spatial distribution using Surfer software. To assess the contamination of well water by nitric pollution, 200 samples were collected in four seasonal campaigns between March 2017 and May 2018, with a rate of 43 samples taken per season. The spatial distribution of nitrates in the groundwater shows that the majority of the catchment points reached by this pollution are located in agricultural areas. Additionally, there was a range of 160.15 mg/L (4.65–164.5 mg/L). The temporal distribution of nitrate in the groundwater of Béni Aamir and Béni Moussa shows an increase in response to the agricultural intensification in this region, and a variation depending on the period of withdrawal. Including the increase in the quality degradation in all wells, from 1% in campaign N°01 to 7.06% in campaign N°02 and to 5.7% in campaign N°03, and to 0% as very bad quality in campaign N°04. The fact that the campaign N°02 has been carried out during the agricultural season, proves the link between the Nitrate pollution and chemical products uses during this period. Therefore, the impact of chemical products uses on the groundwater quality in this region.