Environmental qualitative assessment of Karaj River sediments (Alborz Province)

In this study, surficial sediments along 9 stations (from Bilqan to Dizin and Varangeh_e Rood) were collected seasonally along 2017-2018 and water quality was assessed using enrichment index (EF) and Pollution load index (PLI).The percentages of sand, silt, clay in the sediment samples were determined (78, 17 and 5 respectively). The mean of Al, As, Cu, Fe, Ni, Pb, Cr, Zn, V, TP and TN in the sediment samples were 7.35±1.99%, 8.0±1.2 ppm, 41.0±30.2ppm, 3.56±0.53% , 24.33±4.87 ppm, 5.9-13.6 ppm and 21.8-28.8 ppm, 15.9±5.99 ppm, 36.08±11.45 ppm , 68.08±08.6 ppm, 88.9±23.3 ppm, 0.1±0.05% and 0.42±0.07% respectively. Based on cluster analysis, Asara and Shahrestanak (group1); Pool-e Khab and Gachsar(group2), Bilqhan, Varangh_e Rood, Hassankader and Dizin (group3); and Pool_e Choobi (group4) categorized into separate groups. In general, the concentration of nutrients and heavy metals in the stations did not exceed the PEL and SEL. The enrichment index for both chromium (0.2) and iron (0.8) showed a degree of non-enrichment at all stations. Other metals showed a low degree of enrichment and have low enrichment levels and, in terms of arsenic concentration, EF have been moderate to severe (4.9±1.1). According to the PLI index (1.35-1.9), all stations were more than one, so it can be concluded that all of them were polluted.