Scientific management of wastewater, regulation of sand mining and land use controls have become imperative to address the deterioration of water quality in rivers, the Kerala State Council for Science, Technology and Environment (KSCSTE) has recommended to the government.

An Environmental Monitoring Programme on Water Quality carried out by the Centre for Water Resources Development and Management (CWRDM) has reported pollution of four river basins, namely Pamba, Chalakudy, Bharathapuzha and Anjarakandi-Mahe-Thalassery. In its report on the findings, KSCSTE has mooted an action plan for river basins.

The report stresses the need for a water policy incorporating wastewater management. It calls for appropriate building rules to ensure water saving, wastewater treatment and reuse. An awareness campaign to promote grey water resuse has also been mooted.

The report calls for a water safety plan for river basins, scientific operation of barrages and bunds, regulation of tourism, better urbanisation and scientific planning based on carrying capacity. It also highlights the need for epidemiological research on water quality and water borne diseases and public participation in water quality monitoring and liquid waste management.

The report observes that heavy inflow of waste materials and sewage from towns, markets, hospitals, factories and slaughter houses has contaminated the Pamba river to alarming levels. Analysis of samples revealed that the water was unfit even for bathing during the Sabarimala pilgrimage season when devotees converge along the banks in large numbers.

All the surface water samples were found to be grossly polluted with fecal coliform and the dissolved oxygen content was reported to be low at many locations. The downstream areas reported concentration of heavy metals.

Most of the groundwater samples collected for the survey were found to be acidic and bacteriologically contaminated. All the stations showed clear evidence of organic pollution.

The survey showed that sand mining, industrial pollution and pesticide contamination were major threats to the Chalakudy river. While locations like Vettilapara reported high water turbidity due to sand mining, pesticide and industrial pollution was detected in water samples from Koodapuzha and Kanjirappilly. Groundwater samples from clay mining areas also showed turbidity and low dissolved oxygen.

E.Coli was present in 70 per cent of groundwater samples and heavy metal contamination was detected in sediment samples.

Analysis of samples from the Bharathapuzha river basin showed moderate pollution. All the stations in the basin reported marginal water quality indicating frequently threatened or impaired status. The observations indicate that the river faces stress due to sewage and organic effluents.

The report observed that bacteriological contamination was a major threat to the Anjarakandi- Mahe- Thalassery river basins. Most of the stations reported marginal water quality while a few were found to be of poor quality. Pesticide residue was detected in some of the samples.