Fluoride contamination has been mostly detected beyond permissible limits in a total of nine areas in Palakkad, Malappuram and Alappuzha districts in Kerala, according to the State Environment department.
The places include Muthalamada, Pallassena, Agali, Sholayur, Koppannu and Vattalakki (Palakkad); Komalapuram-1, Pazhaveedu (Alappuzha); and Manjeri (Malappuram).
The source of contamination is probably geogenic in nature, which means these constituents are already in the rock or soil matrix and get into the groundwater through various chemical processes, according to a report dated February 16, 2024 filed by the department before the Principal Bench of the National Green Tribunal (NGT), New Delhi.
It was given to illustrate the current status of Kerala with regard to the case pending before the Bench based on a report by the Union Ministry of Jal Shakti which stated in December 2023 that arsenic has been detected in groundwater in parts of 230 districts in 25 States and fluoride in 469 districts in 27 States.
The Ministry had stated that the arsenic has been detected in the groundwater in Kollam district, while fluoride content was detected in Palakkad, Alappuzha, Idukki, Ernakulam, Thiruvananthapuram and Malappuram.
Maximum permissible limit
According to the Bureau of Indian Standards, the maximum permissible limit of arsenic in groundwater meant for drinking is 0.01 mg/l, while the corresponding limit of fluoride is 1.0 mg/l, which can be extended to 1.5 mg/l in case no alternative source of water is available.
The Environment Department had asked the Central Ground Water Board (CGWB), the State Groundwater department, the Centre for Water Resources Development and Management (CWRDM), and Kerala State Pollution Control Board (KSPCB) to submit a report based on the findings of the Ministry.
The study by the CWRDM, which focussed mainly on regions in Palakkad district, found that Sholayur panchayat in Attapady block was grossly contaminated with fluoride. The CGWB reported fluoride content at Manjeri (Malappuram); Koppanur and Vattalakki (Palakkad); and Pazhaveedu, Komalapuram-1 in Alappuzha. The central lab of the KSPCB found occurrence of arsenic beyond permissible limits in a sample collected from a well at Kureepuzha, Kollam, in October 2023.
The board is carrying out further studies to ascertain the cause of contamination.
The report by the State Groundwater department showed fluoride concentration of greater than 1.5 mg/l at Kannambra, Kalladikode, Cheruplacherry, Mannarkad, Nallepilly and Elavancherry (Palakkad); and Ramankari (Alappuzha).
Remedial measures
The report submitted before the NGT stated that the government plans to conduct spatial analysis studies in the affected areas. The State Groundwater department will initiate remedial measures such as setting up rainwater harvesting facilities, reverse osmosis plant and use of surface water for drinking purposes by involving the services of Kerala Water Authority (KWA) and the Water Resources department, it said.
