Every winter, boatmen row into Srinagar’s Dal Lake to harvest water chestnuts, a fruit that feeds families and stocks local markets. A new study finds the lake is quietly loading that fruit with toxic metal.
Researchers from King Khalid University and partner institutions tested water, sediment and water chestnut tissue from four Kashmir lakes — Dal, Hokersar, Manasbal and Wular — for eight heavy metals. They published the results in Scientific Reports. Dal Lake came out far dirtier than the other three.
Cadmium in water chestnut fruit from Dal Lake reached 0.11 milligrams per kilogram — about 5.5 times the World Health Organization’s safety limit of 0.02 milligrams per kilogram. Zinc in the fruit also exceeded WHO guidelines.
The researchers ran the numbers through standard U.S. health-risk formulas. Cadmium in the Dal Lake fruit crossed the danger line. Every other metal stayed within safe limits.
Where the Contamination Comes From
The study traces the problem to untreated sewage. Srinagar generates roughly 193 million litres of wastewater daily; about 140 million litres go untreated, much of it reaching Dal Lake. Agricultural runoff, urban waste and houseboat discharge add to the load.
The lakebed tells the same story. Dal Lake sediment carries more than double the cadmium found in Wular Lake, the cleanest of the four sites, and blows past Canadian sediment safety guidelines.
The plant’s roots soak up far more metal than any other part. Iron in Dal Lake roots hit 322.5 milligrams per kilogram, the highest reading in the study. Zinc followed at 82.5 milligrams per kilogram.
Little of that metal travels up to the fruit. The plant mostly traps it in the roots instead. That protects the part people eat — but doesn’t clear it entirely.
That same trait — pulling metal out of the water and holding onto it — makes the plant useful somewhere else. Scientists could plant water chestnut on purpose to clean polluted lakes, a low-cost method called phytoremediation.
But that upside doesn’t erase the food-safety problem. Cadmium is a known carcinogen that damages kidneys. Even small amounts in edible fruit deserve monitoring, the study’s authors wrote — not a shrug.
What’s at Stake for Local Families
Kashmiris call the fruit “singhara,” and it’s more than a snack. Rural families wade into the shallows, harvest it by hand, and sell it at local markets each winter — a food and income source many depend on.
That dependence complicates any fix. Ban harvests in the dirtiest zones and consumers stay safer, but families lose a paycheck.
The researchers want three things done: treat the sewage before it reaches the lake, restrict or screen harvests from the dirtiest zones, and test water chestnuts sold in local markets each season.
They caution their data covers just one harvest season and doesn’t show how contamination shifts through the year. Future studies, they say, need to track that.
Dal Lake draws tourists for its houseboats and shikara rides. For the families who still harvest its water chestnuts for dinner, the lake’s postcard image and its pollution problem now sit on the same plate.
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