Residents living around Varthur Lake spend an extra Rs 100 every month on mosquito repellents since the lake has become more polluted. According to a survey carried out by a researcher from Indian Institute of Science and K K School students, around Rs 30,000 is spent per year to rid the place of mosquitoes. The survey was carried out in the last 18 months and the report reveals several other associated problems with the lake pollution. Sample this. Municipal solid waste dumped in the lake catchment and untreated sewage and effluents released into lake have affected the health of local residents. Increased cases of Malaria, fever, dysentery and skin diseases (dermatitis) have been reported from around the lake.
If people are suffering due to increased pollution, the waterbody and its dependents such as waterfowls (aqua birds) are also under threat. Residents say borewell water is being contaminated too. “Profuse growth of exotic plant species such as water hyacinth and exotic fish culture has also contributed to extinction of native species of fauna. Prolific macrophytes lace the water surface completely lessening dissolved oxygen level and hindering the photosynthesis process. Algaeal communities depending on photosynthetic activity have declined and mortality of sensitive life stages inside water has also risen,” said Dr T V Ramachandra, who led the survey.
During the survey the residents also reported poaching of waterfowl such as Purple moorhen, Spot billed Pelican (Pelicans are protected under schedule 1 of Wildlife Protection Act along with tigers and elephants), Common coot and White-breasted water hen, resulting in the decline of their numbers. “Enhanced sewage and effluents inflow coupled with excess exploitation of wetland goods are prime reasons for the decline in indigenous fish species and prevalence of invasive species during the last two decades. Dominant fish species reported in Varthur during 1960s such as Clarias batrachus, Heteropneustes fosslis and Mystus dittatus have dwindled in numbers or almost gone extinct from the lake,” said the researchers who worked on the survey.
