Assessment of nutrient contamination in surface water, case study of Ain Zada Dam (North-East of Algeria)

Abstract

In order to evaluate the impact of potential pollutions on the water quality in the watershed of the upstream of wadi Boussellem (North-east of Algeria), the evolution of the chemical composition of waters of the Ain Zada dam was studied over a period of ten years. Using a linear  model  of  trends and a  principal  components  analysis  (PCA)  methods,  have  been detected and quantified for the substances that are connected with the fertilizers and domestic effluents. An increasing concentration is observed for most of these substances. The increase of 88% in COD, 66% in BOD₅  and the decrease of 4.3% in pH, suggests a degradation of O.M 85% by microorganisms. This degradation was accompanied by a decrease of 2% of O_2dis  content. The large increases of E.C 76%, NH₄  290% and NO₂  100%, are related to a marked  increase  in  fertilizers  applications  and  the denitrification  of NO₃  where  latters declined by 77%. These increases are related also to the large amount of human and animal organic materials and industrial waste dumped.

Keywords: Pollution; Eutrophication; wadi Boussellem; microorganisms, fertilizers