Alappuzha groundwater has heavy metal

A new study published in Scientific Reports has found localised heavy metal contamination in the coastal groundwater of Kerala's Alappuzha district. About 32% of pre-monsoon and 34% of post-monsoon samples fell into medium-to-high pollution categories for selected metals, with specific hotspots for arsenic, aluminium, and iron. For a detailed look at the data, see our stats page.

While most groundwater samples remained within permissible limits, the research flags concerning exceedances in certain areas. The lead researcher, S. Selvam, a senior assistant professor of geology at V.O. Chidambaram College, emphasised the findings point to localised contamination rather than widespread degradation. He said the system is not severely polluted overall, but shows localised and process-driven contamination, especially in shallow coastal aquifers.

Contamination hotspots and sources

The study, which examined groundwater quality before and after the monsoon, identified specific locations where heavy metal levels surpassed World Health Organization guidelines. The contamination is attributed to a mix of natural geological processes and human activities like commercial debris, agricultural runoff, domestic sewage, and tourism.

Shaji E., a professor of geology at the University of Kerala, cautions that the arsenic findings warrant further verification. He notes they differ from earlier studies and Central Ground Water Board assessments. While calling for improved analytical techniques, he shared that the study, while academically valuable, may overstate the environmental and public health risk without sufficient corroborative evidence, potentially leading to unnecessary concern. In response, Selvam stated the research followed standard quality assurance procedures.

Health and community impacts

Prolonged exposure to elevated levels of these metals carries health risks. Arsenic is associated with carcinogenic and cardiovascular dangers. Aluminium and excessive iron can affect the nervous system and cardiovascular health, respectively.

Local health officials separately pointed to fluoride concerns. A medical officer at Purakkad Primary Health Centre, speaking anonymously, noted cases of dental fluorosis, including brown teeth staining among children, in areas where groundwater is still used for drinking. Sherleena J., a teacher at Government High School Nalamchira near Thottappally, said a medical camp identified dental fluorosis among students, prompting the school to provide reverse osmosis-treated water.

Seasonal stresses and water insecurity

Residents face immediate water-quality challenges beyond heavy metals. In Paravoor, shallow wells near the sea often turn saline in summer, forcing dependence on government water schemes. Mariyamma, 63, says her community has relied on pipelines since the 2019 floods, rarely using wells for drinking due to increasing salinity.

Monsoon brings other problems. Lata John, 57, described how heavy rains leave well water unusable. She said the runoff from Vembanad lake and adjacent paddy fields carries decomposed straw and organic matter from submerged fields, rendering the well water unpotable. This unreliability increases dependence on alternatives. Anit Nirmala, a 32-year-old pregnant resident, refuses piped water due to its chlorine taste. She said they buy a 20-litre RO water can every day for drinking and cooking.

The burden falls unevenly. Families relying on shallow wells, those with interrupted piped supply, pregnant women, the elderly, and lower-income households often have fewer options when local sources fail. For more on community impacts, see our fixtures page.

Monitoring and the path ahead

Medical officers in Purakkad and Ambalapuzha, speaking anonymously, stated no official health cases linked to high contamination have been reported so far. Primary and Urban Health Centres conduct periodic tests on water from hotels and RO plants, with follow-up action taken when concerns are identified.

Officials acknowledge household-level monitoring of private shallow wells is limited. Residents can approach their local health centre to test well water. A junior health inspector collects the sample, which is analysed at the district laboratory for a fee starting from Rs. 100 for basic tests.

The researchers recommend a combination of treatment technologies and preventive measures. They suggest iron-based adsorption for arsenic removal, coagulation-filtration for aluminium, and nature-based approaches like phytoremediation. They call for continuous long-term monitoring of groundwater to validate the study's findings.