Assessment of groundwater pollution by nitrates using intrinsic vulnerability methods: A case study of the Nil valley groundwater (Jijel, North-East Algeria)

Abstract

Scientists are deeply concerned with the state of vulnerability of groundwater reservoirs. It is a complex task because of the difficulties in determining the degree of pollution of the ground water. Many methods have been adopted like DRASTIC, GOD, SI, SINTACS, etc. The present article targets the determination of the vulnerability of groundwater reservoirs of a climatic Mediterranean region (Nil valley region, Jijel). The excessive use of fertilizers in agriculture has been the main reason behind the increase of the Nil valley groundwater pollution with nitrates (Jijel, North-East Algeria). In fact, the use of fertilizers in high quantities relatively to the needs of the plants lead to the leaching and infiltration of the excess fertilizers into groundwater which increases the nitrates percentage; as a result, the allowed norms of water consumption are exceeded. Relevant to this, the aim of this study was to assess the aquifer vulnerability caused by pollution with nitrates using DRASTIC, GOD and SI methods. The spatial distribution of the found nitrates in groundwater shows that the DRASTIC method is the most appropriate method in this case with a percentage of 71% vs. 54 and 63% for GOD and SI methods, respectively. Moreover, it was found that the studied water is characterized by a medium to high degree of vulnerability. Pertinent to this, it is highly recommended to find solutions to better protect and preserve the Nil valley groundwater.

Key words: Aquifer vulnerability, pollution, nitrate, agriculture, groundwater protection.