Monitoring water quality of Coimbatore wetlands, Tamil Nadu, India.

Signs of wetland-water quality degradation have been apparent for decades, especially in those wetlands situated in the vicinity of cities and human habitations. Investigation on four urban wetlands of Coimbatore have been undertaken to assess the water quality with reference to pollution from various sources. The pH and total dissolved solids (TDS) values of the lakes were found to be different from those reported almost a decade back. The concentrations of phosphate and sulphate were much lower than the earlier reported values. The present scenario states that though the biochemical oxygen demand and chemical oxygen demand values were lower for the Ukkadam wetland, the values for Perur wetland have shown a gradual increase. Alkalinity and chloride concentrations were thrice higher than the previous findings. Electrical conductivity and TDS ranged from 303.67 to 4,456.7 muS/cm and from 169 to 2,079.3 mg/l, respectively, and were positively correlated with chloride and sulphate (P < 0.05). These changes are a reflection of the environmental changes happening in the cityscape of the Coimbatore, a fast-growing city in south India.