Followed by Hokersar, Manasbal; Wular shows lowest concentrations
Srinagar: Water chestnut harvested from Kashmir’s Dal Lake has accumulated elevated levels of certain heavy metals, including cadmium and zinc, with concentrations in the edible fruit exceeding permissible limits cited in a new study, raising concerns over potential food-safety risks.
The study, published in Scientific Reports, analysed water, sediment and water chestnut (Trapa natans) samples from four major water bodies of Jammu and Kashmir — Dal Lake, Hokersar Wetland, Manasbal Lake and Wular Lake — for eight heavy metals.
The researchers found a clear pollution gradient, with Dal Lake recording the highest levels of heavy-metal accumulation, followed by Hokersar, Manasbal and Wular.
The edible fruits of water chestnut collected from Dal Lake contained cadmium at 0.11 milligrams per kilogram, about 5.5 times the 0.02 mg/kg limit cited by the study. Zinc concentrations in the fruit reached 18.21 mg/kg, nearly 30 times the 0.60 mg/kg guideline value cited by the researchers.
The study, accessed by the news agency—Kashmir News Observer (KNO), however, does not establish that eating water chestnuts from Dal Lake causes illness. Rather, the findings point to the need for continued monitoring of contaminants in aquatic food products and their potential movement through the food chain.
The researchers found that heavy metals accumulated most strongly in the roots of the water chestnut, followed by shoots and fruits, indicating that the plant retains much of the contamination around its root system.
Iron was the most abundant element detected. Its concentration in roots from Dal Lake reached 322.50 mg/kg, while zinc reached 82.45 mg/kg in roots. Cadmium in Dal Lake roots was recorded at 0.42 mg/kg.
The researchers also found substantial differences between the lakes. Wular recorded the lowest heavy-metal concentrations among the four water bodies, while Manasbal also showed comparatively lower contamination. The authors attributed the differences partly to variations in external pollution sources and water exchange.
Sediment analysis provided another important finding, with Dal Lake showing the highest enrichment of heavy metals. The researchers reported that several metals, including cadmium, chromium, nickel and iron, exceeded Canadian sediment-quality guideline thresholds in parts of the sampled sediment.
The study also identified a potentially useful environmental role for water chestnut. Because the plant efficiently accumulates metals, the researchers said it could serve as a biological indicator of pollution and potentially have applications in phytoremediation—(KNO)
