PANAJI: Concerns over the safety of seafood harvested from Goa’s coastline have intensified after the Centre for Promoting Indian Economy (CPIE India) expressed serious concern over cadmium contamination in oysters. The warning comes shortly after a scientific study conducted by the National Institute of Oceanography (NIO) highlighted the presence of elevated cadmium levels in oysters collected from various locations along the state’s coast.
CPIE India described the findings as “extremely alarming,” noting that the issue has significant implications for public health, particularly for communities that regularly consume oysters. The CPIE India observations follow widespread attention generated by the NIO research, which warned that prolonged consumption of cadmium-contaminated oysters could increase health risks’ and may be particularly dangerous for children.
CPIE India researchers corroborated their own studies with the results from the NIO to arrive at similar conclusions leading to the “alert”.
The NIO study, published last month under the title “Distribution, Bioaccumulation and Human Health Risk of Mercury and Cadmium in Coastal Sediments and Oysters along the Goa Coast, India,” examined the presence of two heavy metals—cadmium (Cd) and mercury (Hg)—in coastal sediments and oysters (Saccostrea cucullata). The objective was to understand how these contaminants are distributed in the marine environment, how they accumulate in shellfish, and the potential health risks associated with their consumption.
According to the researchers, oysters collected from several sampling sites along the Goan coastline contained cadmium concentrations above the recommended food safety limits. The elevated levels were attributed to the shellfish’s natural tendency to accumulate contaminants from their surrounding environment, a process known as bioaccumulation.
The study concluded that cadmium currently represents the most significant environmental and public health concern along Goa’s coast, while mercury levels remain comparatively low and do not pose a similar level of ecological or health risk at present.
Interestingly, the findings revealed that the coastal sediments themselves remain relatively uncontaminated. The average concentration of cadmium in sediment samples measured 0.16 mg/kg, well below internationally accepted sediment quality guidelines. Mercury concentrations were even lower, averaging just 0.005 mg/kg, suggesting that the seabed is not experiencing widespread heavy metal pollution.
However, the situation was markedly different when researchers analysed oyster samples. The average cadmium concentration in oysters reached 3.37 mg/kg, exceeding permissible safety limits at most of the surveyed locations. Mercury concentrations in oysters averaged 0.071 mg/kg, remaining comfortably within accepted seafood safety standards.
Scientists also carried out a detailed geochemical assessment to identify areas with higher contamination. The analysis detected localized cadmium enrichment near Baga, while mercury contamination was found to be negligible across the remaining stretches of the coastline.
The study further evaluated the potential health implications for consumers through internationally recognised risk assessment methods. Researchers found that cadmium was the primary factor contributing to elevated Target Hazard Quotient (THQ) and Hazard Index (HI) values, both of which are widely used indicators to estimate the non-carcinogenic health risks associated with long-term exposure to contaminants.
The findings indicate that individuals who consume contaminated oysters regularly may face increased health risks due to cadmium exposure. Mercury, on the other hand, remained well below levels considered harmful to either marine ecosystems or human health.
Researchers emphasised that while Goa’s coastal sediments continue to show encouraging environmental quality, the significant accumulation of cadmium in oysters demands closer scientific attention. They stressed the importance of continuous monitoring of heavy metals in marine ecosystems, particularly in shellfish species that are known to concentrate contaminants over time.
Experts believe that sustained surveillance, improved environmental management, and periodic testing of seafood will be essential to protect public health and preserve Goa’s coastal food resources. The latest warning from CPIE India, coupled with the NIO’s scientific findings, is expected to intensify discussions on food safety, marine pollution, and the need for stronger monitoring mechanisms along the state’s coastline.