Potentially toxic metals in sediments, lake water and groundwater of the Ramsar wetlands Bakhtegan–Tashk, South Iran: Distribution and source assessment

Bakhtegan–TashkLakes (BTL) and Kamjan Marsh, one of the Ramsar sites with an area 1323 km 2 , have been shrunk due to groundwater overexploitation, construction two new dams drought. Evaporation BTL water significantly increased potentially toxic metal (PTMs) average total dissolved solids (TDS) from 45000 382000 mg/l. This study focuses on contamination sources 16 PTMs. The sampling include 24 sediments, surface salts, 17 samples Bakhtegan Lake (BL), wells. PTMs were analyzed in Act Lab. sediments are contaminated by Hg, Ni, Mo Se based CF, EF, I geo indices at ecological risks Ni Cr SQGs index Hg Risk index. Marsh adjacent aquifer negligible risk. Most concentrations not measured dilution. BL below bed and/or risk high values TDS measurable Mo, Pb, V, As, Mn Sb. most probable chromite mines, sewage petrochemical industrial complexes, dust west Iran Iraq, combustion fossil fuel fertilizers. can be restored a resource plan save installing meters all exploited wells, modern irrigation systems, optimizing crop patterns, enhancement yield per unit applied water, stakeholder cooperation. • has recent decades, resulting for aquatic life. Se, As main sediment contaminants parts BTL. contaminations originate mixed geogenic anthropogenic sources. resources water-saving strategies.