Algal bloom has resulted in heavy pollution on the Kumbazha-Kallarakkadavu stretch of the Achencoil river, posing a grave public health risk in the Pathanamthitta municipal limits.
A study conducted by Binoy T. Thomas and V.P. Thomas of the Department of Botany at Catholicate College here, in association with the Kerala State Council for Science, Technology and Environment and the Directorate of Environment and Climate Change, has found excessive growth of Euglena sanguinea and other algae along the mostly stagnant river stretch.
Dr. Thomas told The Hindu that eutrophication — excess nutrients in water — and environmental changes were identified as the cause of the harmful algal blooms in the fresh aquatic system of the Achencoil. The Konni block panchayat, which had taken notice of the issue after those bathing in the river complained of skin problems, had convened a meeting to discuss the problem a year ago, Dr. Thomas said.
According to him, the algal bloom that even changes the colour of the waterbody indicates the high pollution level caused by a heavy load of nutrients, fertilizers, and septic sewage. The check-dam on the riverbed at Kallarakkadavu, meant for recharging groundwater and wells during summer, has turned the river stretch into more or less a stagnant pool of polluted water, he said.
Fish perish
The algal bloom, spread over the river surface as thick scum, prevents the entry of atmospheric oxygen, thus killing fish and other aquatic organisms. Water quality tests on the stretch found that the coliform bacteria count was 1,800 in every 100 ml against the maximum permissible limit of 500 per 100 ml. An inspection by the State Pollution Control Board detected high coliform count along the river stretch. Dr. Thomas stressed the need to initiate safety measures.
