PANJIM: While heavy metal contamination in water bodies is not a new phenomenon, growing human activity and the unregulated discharge of hazardous sewage are exacerbating the problem. This, in turn, poses serious health risks to those who depend on marine species for food, said experts reacting to a recent study by the National Institute of Oceanography (CSIR-NIO) which has flagged dangerous levels of cadmium contamination in oysters harvested along the Goa coast, warning that regular consumption poses serious health risks.
Former Chief Scientist, CSIR-NIO Arvind Kumar Saran said that the research reveals alarming levels of Copper (Cu) and Cadmium (Cd) in oysters (Crassostrea madrasensis, C gryphoides, and Saccostreacucullata) across all studied sites and seasons, significantly exceeding recommended safe limits for human consumption.
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“This contamination poses a severe threat to public health. The primary driver of this pollution appears to be unregulated and unmonitored industrial discharges, including those from small-scale industries and established industrial estates like Verna. There are ongoing concerns regarding inadequate effluent treatment and a lack of transparency, often exacerbated by bureaucratic hurdles that restrict media and scientific scrutiny,” Saran said.
To address these critical public health and environmental risks, the government must prioritise transparency over the fear of negative publicity.
“We urgently need robust monitoring mechanisms, increased public awareness, and the strict enforcement of environmental regulations. Bringing these hard facts into the public domain will foster constructive, solution-based dialogue to safeguard the health of our citizens and the environment,” he said.
Architect and water conservationist Tallulah D’Silva said that according to a report by the Goa State Pollution Control Board, approximately 15 riverine water bodies are heavily polluted, primarily due to sewage and potentially unmonitored industrial waste disposal, such as from the Verna industrial area.
“Furthermore, conventional septic tanks and soak pits are failing to adequately filter the high volume of waste generated by modern developments. The extensive use of strong household detergents and chemical cleaners introduces carcinogens and toxins into the groundwater, which ultimately compromises both public health and the environment,” she said.
To address this issue, there is a critical need to transition from centralised systems to decentralised waste management solutions.
“Encouraging the use of eco-friendly alternatives—such as bio-enzymes and effective microorganisms—alongside institutional demonstrations of natural water treatment methods on government campuses, could significantly reduce groundwater contamination,” D’Silva said.
Gastroenterologist at Manipal Hospital, Dr Akshay Jain said that two contaminants that have gained considerable attention over the last few years are cadmium and mercury.
“These heavy metals can find their way into our food chain through various pathways, raising alarms about their potential impact on human health. Cadmium enters the food chain through contaminated soil (absorbed by leafy vegetables, rice, and grains) and water pollution (accumulating in fish and shellfish). Chronic exposure causes kidney damage, decreased bone density, and an increased risk of lung and prostate cancers,” Dr Jain said.
“For mitigating these risks, there is a need for collaborative efforts. Steps like enforcing strict government regulations, adopting sustainable agricultural practices to reduce cadmium fertiliser use, managing wastewater, regulating fishery emissions, and raising public awareness are necessary,” he said.
Senior cardiologist Dr Francisco Colaco said that oysters bioaccumulate cadmium from coastal waters, a growing concern in Goa due to regional runoff.
“Although packed with zinc and healthy fats, cadmium lingers in human kidneys for decades. I personally caution frequent shellfish consumers, smokers and renal patients to strictly limit intake to prevent serious chronic metal toxicity,” Dr Colaco said.
