Investigation of possible effect of Urmia Lake drying on quality of drinking water resources of lake's eastern outskrit

Abstract

Introduction The purpose of this study was the assessment of groundwater quality and salinity and Investigation of possible effect of Urmia Lake drying on quality of drinking water resources of lake eastern coastal. Methods For this purpose، 14 pHysicochemical parameters from 320 groundwater wells during 15 years (2003-2018) were used which included 6802 datasets (74822 quantitative data). Required information was collected from three Organization، including the Regional Water Organization، the Water and Wastewater Engineering Company، as well as the Ministry of Health. The data were first sorted in Excel and Spss. Then they were evaluated and analyzed using multivariate statistics and hydrogeochemical analysis in SPSS. GIS and AqQA softwares were also used. Results and Discussion Among the drinking water wells، 61.5% of the wells were suitable for drinking (less than 500 mg/l)، 33.1% acceptable for drinking (500-5000 mg/l)، 5.4% suitable for drinking And irrigated (1000-1000 mg/l). The highest increase in the amount of drinking water were related to sulfate (27%)، total disolved solids (19.3%)، calcium (15.4%)، bicarbonate (13%)، and chlorine-magnesium-Sodium (12.3%) and then potassium (8%). Most concern about TDS and its health effects is related to northwest Azarshahr plain and east of Shabestar plain. According to the results of multivariate statistical analysis، 6 clusters were obtained in the region. Cluster 3 known as the charging zone (Ca-HCO3)، cluster 1 (Ca -HCO3 -Cl-mg) weathering، cluster 4 (Ca-Cl) influenced by saline water up-coning during agriculture pumping. The chemical composition of clusters 6 and 2 was usually Ca-Cl-SO4، this type of groundwater chemical being related to the influence of agricultural and sewage. Cluster 5 (Na-Cl type) water may be influence by saline soil rather than lake retreat and lake water intrusion. The role of Urmia lake in the degradation of the overall water quality in the region is restricted to clusters 4 which comprise northwestern Azarshahr، west Ajabshir، middle part of the Osko plain and cluster 5، northeast and east of Shabestar and west of the Osko and northwestern Bonab plain Includes salt plain. The role of the lake in degradation of drinking water quality is is restricted to cluster 4 in northwest Azarshahr. Conclusion The Urmia lake is not involved in the contamination of groundwater resources naturaly، but the overuse of groundwater resources in the area contributes indirectly to the lake، especially saline soils Remained by the lake's retreat over the years، as well as brines water in the deep groundwater wells adjacent to the lake، this has in some cases reduced the quality of drinking water. On the other hand، agricultural fertilizer and sewage have been effective in reducing quality.