This study focused on assessing the spatial and temporal variation of pollutant load at six sites along the Tamla Nala, a natural water channel which drains into the River Damodar. Before the discharge point into the river the values of pH (10.23), total suspended solids (745.25 ± 48.98 mg/l), chloride (1218.51 ± 228.86 mg/l), cyanide (0.876 ± 0.348 mg/l), COD (316.8 ± 34.02 mg/l), oil and grease (14.35 ± 1.37 mg/l), total iron (3.62 ± 0.69 mg/l), lead (0.475 ± 0.092 mg/l) and mercury (0.061 ± 0.01 mg/l) exceeded the discharge norms for inland surface waters applicable in India. Factor analysis was found instrumental in delineating the sources of the pollutants and the nature of pollution at the various sites. Calculation of different pollution indices like contamination index (Cd), heavy metal evaluation index (HEI) and total pollutant enrichment index (TPEI) at different sites showed that their values increased downstream. The values of Cd increased from 0 at Site 1 to 21.27 at Site 6, that of HEI from 0.25 to 12.25 and that of TEF from 1 to 13259.35. Therefore Site 1, was identified as unpolluted, while the sites near heavy industries were classified as highly polluted.
Keywords: water quality, spatial variation, temporal variation, factor analysis, pollution indices, water pollution, natural channels, industrial wastewater, India, discharge norms, heavy metals