Water quality assessment of the Zarivar Lake using physico-chemical parameters and NSF- WQI indicator, Kurdistan Province-Iran

Abstract

The Zarivar Lake a freshwater lake in west of Kurdistan Province is home for large number of native plant and animal species therefore water quality and health of the lake are vital for conservation of these species. The present study aimed at evaluation of the Zarivar Lake using NSF- WQI as an indicator of water quality. WQI is a suitable tool to examine and classify spatial and temporal variations in water quality and pollution loads in a water body. Seven sites were selected in different parts of the lake for sampling. Water samples were taken and placed in dark bottle, kept in ice box to prevent any change in chemical properties of samples prior to transportation to the lab for further analyses. Nitrite, Nitrate, Orthophosphate, NH₄⁺, NH₃, Iron, salinity, Electron Conductivity (EC) and pH were measured in all sites. Electron Conductivity was 295- 426 µS.cm^-1 and pH varied between 7.28- 8.35. Concentrations of examined chemicals were PO₄^3-: 0.019-1.45 mg l^-1 ،NO3-:0.6 mg l^-1 ،NO2: 0.001-0.011 mg l^-1 ،NH₄⁺ :< 0.11-11.33 mg l^-1 which indicated trophic status of the lake. Water quality assessment was carried out based on values obtained for nine factors including dissolved oxygen (DO), Fecal Coliform, BOD, pH, water temperature (^oC), Phosphate, Nitrate, Total Suspended Solid (TSS) and turbidity. The highest value was recorded for Nitrate and lowest for fecal coliform. The study showed based on WQI indicator the Zarivar Lake is a low or slightly polluted basin with an average water quality.