Assessment of water quality status of some water bodies in Kolkata

Abstract

The water quality status of some water bodies in Kolkata were assessed during dry season through the analysis of various physico-chemical and biological components. Studies revealed that water of all the ponds were alkaline with pH value ranging from 7.80 to 8.41 at water temperature between 28.0 and 28.5. Total Dissolved solids (TDS) varied from 310 to 710 mg/L with higher in Science city (710 mg/L), followed by Victoria (366 mg/L), B.B.D.Bag (310 mg/L) and Minto park (250 mg/L). Minimum of 56% dissolved oxygen saturation values were observed in the pond of Science city implying presence of higher oxygen demanding waste and maximum (96%) in B.B.D.Bag indicating lowest level of reducing substances. Lower ratios of BOD/COD ranging from 0.18 to 0.29 implied the presence of comparatively higher level of non-biodegradable organic matter in water. According to National Sanitation Foundation Water Quality Index (NSF-WQI) values, water quality of two ponds (Victoria and Minto park) were classified as good to excellent, one (B.B.D.Bag) is medium to good and another (Science city) is bad which corresponded to the class A, B and C respectively as classified by Central Pollution Control Board (CPCB).