Geochemical study of water and sediments in the Badavar River, Lorestan Province: environmental iImplications

Abstract The Badavar River is an important surface water resource in Lorestan province. The purpose of this study is to assess the quality of the Badavar water and sediments. For these purpose, 19 water and five surface sediment samples were collected. The physicochemical properties of the water (i.e. pH, electrical conductivity, the major ion concentrations, microbial analysis, and potentially toxic element concentrations) and sediment samples (i.e. pH, organic matter, carbonate calcium, cation exchange capacity, major and trace element concentrations) were determined using standard methods. The obtained results indicate that the concentration of major ions influenced by natural processes (i.e. halite and gypsum dissolution, calcite, aragonite and dolomite precipitation, and ion exchange) and anthropogenic factors (i.e. discharge of domestic wastewater and agricultural runoff into the river). The concentration of the potentially toxic elements, especially Pb, is influenced by anthropogenic activity. The results of the microbial analysis confirm the pollution of the water samples with pathogenic agents. On the basis of pH values, the sediment samples are placed in neutral to alkaline class. Sediment samples are rich in organic matter and CaCO3, and their cation exchange capacity is high. The total concentration of elements in sediments shows that there is a risk of pollution with Cd, Cr, and Ni. The contamination degree values show that the studied sediments are highly polluted, which is due to the discharge of urban and agricultural wastewaters into the Badavar River. Keywords: Hydrogeochemistry, pollution, Sediment, Badavar River Introduction Rivers are the most available water resources for different usage purposes in the world (Chidya et al. 2011). The environmental quality of surface waters is influenced by both natural and man-made factors, the most important of which are mixing, mineral precipitation/dissolution, ion exchange, and discharge of the urban, agricultural and industrial wastewaters (Suthar et al. 2009; Zhang et al. 2010). Naturally- and anthropogeically- sourced pollutants are typically distributed between water and sediments. Therefore, for evaluating the environmental pollution of the river systems, both water and sediment chemistry must be considered. River sediments usually act as a sink and source for the pollutants; therefore, they are a very important component of river systems (Malvandi 2017). The Badaver is an important river