Drinking water quality modeling and analysis with application of PCA and GIS in the villages of western edge of the Urmia lake

Abstract

Groundwater is one of the most important sources of drinking water in many societies. Geological structure of each area, which is a prominent natural factor, plays a significant role in the water quality, especially chemical aspects. So that, it can be said the general quality of the groundwater is strongly affected by the geology of the same area. Also, among anthropogenic pollution sources, there are pollution due to human activities such as municipal, industrial and agricultural wastewaters and different types of solid wastes that have impact on water resource quality. Therefore, in order to protection of consumers’ health, monitoring the water quality as well as hydrochemical factors are necessary. To reach research’s goal, we collected data from villages which are located at western bank of Urmia Lake including cities of Urmia, Salmas, Naqadeh, Mahabad and Miyandoab. The main objective of this study was defined as zoning, qualitative analysis and description of drinking water sources in mentioned cities using geographical information system (GIS). Our sample consisted of 121 drinking water wells and spring at 301 villages. Using Arc GIS, all physicochemical parameters, heavy metals such as arsenic were analyzed, and then thematic maps were plotted. In addition, Piper, Stiff, Schoeller and Wilcox diagrams were developed and interpreted. Finally, we employed Principal Component Analysis (PCA) to analyze data, and then considered parameters adaptability with standards has been examined. Our results indicate shortages in maintaining water supplies such as lack ofII fencing and adjacency water wells to contamination sources which could affect water quality. pH level in the water supply of Kashtiban village at Urmia was as low as 6.36. TDS of more than 80% of groundwater was in the range of 500-1000 mg/L which is suitable for drinking. In villages of Golenji (well 1,2), Kashtiban, Ghahremanloo Olya, Khandam, Hamzeh Kandi, Bargoshad and some other villages, our findings reveal that the amount of TDS were slightly higher than standard boundary of 1000mg/L which make water unsuitable for drinking purposes. According to schoeller diagram, we considered water with TDS higher than 1000 mg/L as the brackish water. The average and range of EC was 1006 and (305 to 3060), respectively. In some villages, EC was higher than favorable limit. For example, in the village of Golenji, EC was about 3000µs/cm which is not suitable to use for drinking. Totally, 68.8% of measured EC was lower than in 1000µs/cm which is suitable for drinking. According to the GIS mapping, it can be concluded that groundwater in the Northern and Southern part of the study area are relatively high in term of EC which can be caused by the influence of the geology of the region. Considering inappropriateness of distributed drinking water respect to some anions, cations, amount of solids and arsenic in some villages, it is required mitigation measures to be conducted for replacement or treatment of water resources.