[www.nature.com]

Accumulation of DDT in Himalayas exceeds that seen in Arctic.

Atmospheric pollution from cities such as Kathmandu drifts up to the Himalayas and the Tibetan Plateau, where persistent chemicals can accumulate.

Toxic chemicals are accumulating in the ecosystems of the Himalayas and the Tibetan plateau, researchers warn in the the first comprehensive study to assess levels of certain organic pollutants in that part of the world.

“The rigour and quality of the work are impressive,” says Surendra Singh, an ecologist at the Forest Research Institute in Dehradun. “It’s the first study to quantify the accumulation of [persistent organic pollutants] in ecosystems in the region.”

Persistent organic pollutants (POPs) are carbon-based compounds that are resistant to break-down. Some originate from the burning of fuel or the processing of electronic waste, and others are widely used as pesticides or herbicides or in the manufacture of solvents, plastics and pharmaceuticals. Some POPs, such as the pesticide dichlorodiphenyltrichloroethane (DDT) and the herbicide Agent Orange, can cause diseases such as cancers, neurological disorders, reproductive dysfunction and birth defects.