Srinagar, August 10, 2026: Water chestnuts harvested from Kashmir’s lakes may be accumulating heavy metals from polluted water, raising concerns over food safety and the deteriorating condition of the Valley’s freshwater ecosystems, according to a study published in Scientific Reports, part of the Nature portfolio.
Researchers examined water sediments and water chestnut (Trapa natans) plants from four major freshwater bodies Dal Lake, Hokersar Wetland, Manasbal Lake and Wular Lake. The study analysed several heavy metals, including potentially toxic cadmium and chromium and found a clear variation in contamination across the water bodies.
Dal Lake records highest contamination
Among the four sites Dal Lake recorded the highest overall heavy metal contamination, followed by Hokersar Wetland. Researchers linked the higher contamination levels to the urban and semi urban settings of these water bodies and the pressure from human activities.
The study found that heavy metals were not restricted to the water and sediments. They were also detected in different parts of water chestnut plants, including their edible fruits.
Water chestnut was found to retain the highest concentration of metals in its roots followed by shoots and fruits. While the strong retention of contaminants in the roots limits their movement through the plant, some metals still reach the edible portion.
Cadmium and chromium raise concern
Iron and zinc accounted for a substantial portion of the metal load detected in the plants. Both are naturally occurring and essential nutrients.
However, researchers highlighted the presence of cadmium and chromium as a greater concern because these metals have no nutritional role in the human body and can pose health risks with prolonged exposure.
The researchers cautioned that the study did not determine the level of consumption required to cause specific health effects in humans. Nevertheless, the detection of toxic metals in edible tissues indicates a possible route through which environmental contaminants can enter the food chain.
The study particularly noted elevated cadmium levels in water chestnuts from Dal Lake and recommended limiting their consumption until effective pollution control and remediation measures are implemented.
Water chestnut could also help monitor pollution
The findings present an unusual scientific possibility. Because water chestnut readily absorbs metals from its surroundings, researchers believe the plant could serve as a biological indicator of water pollution.
The same ability could potentially make it useful in phytoremediation a process in which plants help remove or contain pollutants from contaminated environments.
However, because water chestnut is also consumed as food researchers stressed that its use for pollution monitoring or remediation would require careful management and regular testing.
Untreated wastewater adds to the problem
The study points to untreated sewage and agricultural runoff as important contributors to pollution in Kashmir’s lakes and wetlands. Wastewater and other pollutants entering water bodies without adequate treatment can affect not only water quality but also aquatic plants and animals.
The findings have also raised concerns about other edible plants harvested from Kashmir’s lakes, particularly lotus stem, locally known as nadru which is an important part of Kashmiri cuisine.
A separate study published previously had also reported that lotus plants growing in Dal Lake can accumulate heavy metals, with much of the contamination retained in underground plant tissues.
Need for regular food safety monitoring
Researchers have called for continued monitoring of heavy metals in Kashmir’s water bodies as well as plants and food products harvested from them.
The study highlights the close connection between water pollution, ecosystem health and food safety. It also underlines the need for stronger wastewater treatment and pollution control measures to prevent contaminants from entering freshwater ecosystems and eventually reaching the human food chain.
The researchers findings suggest that protecting Kashmir’s lakes is not only an environmental priority but also increasingly a public health and food security concern.