Water quality in Periyar river not on expected lines, says CPCB

Water quality parameters at 13 Periyar river stations in Kerala failed to meet national standards, impacting fish health and bathing safety.

The water quality parameters at 13 monitoring stations along the Periyar river in Idukki, Thrissur and Ernakulam districts failed to comply with the norms of the National Water Quality Monitoring Programme in the period between January and December 2024.

The analysis revealed that all 13 locations failed to meet the Primary Water Quality Criteria for Outdoor Bathing, as notified under the Environment (Protection) Rules, 1986. The parameters of non-compliance included Dissolved Oxygen (DO), pH, Biochemical Oxygen Demand (BOD), Faecal Coliform, and Faecal Streptococci, according to the Central Pollution Control Board (CPCB).

The analysis was carried out by the CPCB in association with the Kerala State Pollution Control Board as part of the national-level monitoring of critically polluted river stretches across the country.

The minimum dissolved oxygen level recorded at Eloor, Bhoothathankettu reservoir, Muppathadam, Kalamassery, and Azhikode ferry, Kodungalloor, was below the desired 5 mg/litre and above the level recommended for optimum fish health.

The biological oxygen demand was above the desired maximum level of 3.0 mg/litre at Kalady, Bhoothathankettu reservoir, Pathalam, Purappallikadavu, the Kerala Water Authority’s intake point in Aluva, and Azhikode ferry, Kodungalloor.

The range of faecal coliform values at Eloor and the sewage discharge point in Aluva exceeded the primary water quality standards for outdoor bathing, surpassing the maximum permissible limit of 2,500 MPN (most probable number)/100 ml. Similarly, the range of faecal streptococci values at the sampling points in Kulamavu reservoir and Panamkutty bridge in Idukki exceeded the primary water quality standards, surpassing the maximum permissible limit of 500 MPN/100 ml, according to official estimates.