Assessment of coastal water quality at Bakkhali, West Bengal (India)

Spatial variations of some physico-chemical water quality of the coastal water of a segment of Bakkhali (Bay of Bengal) were studied between the months of November 2009 and February 2010 before 12:00 a.m. The studies were carried out at three coastal sites of Bakkhali Beach (south extreme point, middle point and far north point, about 1.2 km along the shore) which is influenced by anthropogenic input from land-based sources. The site receives domestic, agricultural and industrial wastes. The water is being used for fishing, transportation of goods and by people for several purposes. The banks of the estuarine channels have traditionally been preferred locations for human settlement. Considering the various uses of this coastal segment, between Bakkhali to Haldia, the studies related to water quality monitoring were carried out. The pH, temperature, turbidity, salinity, TDS and conductivity vary in range of 8.24 - 8.65, 27.5 degrees C-31.5 degrees C, 480 NTU - 808 NTU, 21.6 PSU-30.0 PSU, 676 mg/L -934 mg/L and 1.72 mS/cm -1.97 mS/ cm respectively. Dissolved oxygen, biochemical oxygen demand (BOD) concentrations at different sites vary within a narrow range 6.05 mg/L - 8.1 mg/L and 1.05 mg/L - 3.0 mg/L respectively. Chemical oxygen demand concentrations vary in a wide range of 170 mg/L - 812 mg/L. The bacterial count at the sampling site varied from 76-150 CFU.