Investigating the water quality of rivers entering the Anzali Wetland

The Anzali wetland, a crucial water ecosystem in Iran, has been receiving water input from various rivers over the years and is currently facing a critical condition. We aimed to determine the proportional contribution of biogeochemical loads of anthropogenic origin by the rivers supplying the wetland. Accordingly, we analyzed monthly data from 2013 to 2015, encompassing discharge, total dissolved solids, calcium, magnesium, potassium, sulfate, chloride, bicarbonate, electrical conductivity, and water acidity in the primary river feeding into Anzali wetland. We found that the Pasikhan River exhibited the highest and Chafrood River the lowest average daily water flow, with 48 m³/s and 0.42 m³/s, respectively. The annual average of total soluble solids introduced into Anzali wetland through Pirbazar and Pasikhan rivers was 164,760 and 205,713 tons, respectively. Additionally, the inflow of other substances such as chloride and sulfate into the wetland is substantial. Overall, more than half of the wetland's water originates from the Pasikhan and Pirbazar rivers in the eastern region, where Pasikhan and Pirbazar rivers are dominantly utilized for agricultural and urban purposes, respectively. Based on the multivariate analysis we quantified the contribution of the rivers and the role of land use in the region as main factors of water quality. To rejuvenate the Anzali Wetland, effective catchment area management and governmental support are imperative, with particular emphasis on prioritizing the Pasikhan and Pirbazar rivers.

Mohammadreza Ojani is funded by the Stipendium Hungarian scholarship under the joint executive program between Hungary and Iran.

The study was elaborated under the research project NKFI K138079.

Keywords: Water Pollution, Anzali Wetland, Water Analyze, Rivers, Water chemical parameters