The Roof of the World has long been associated with notions of adventure, beauty, and the majesty of some of the tallest mountains on earth. However research has shown that amidst the stunning landscape of the Tibetan Plateau and Himalayas lie dangerous, toxic chemicals known as persistent organic pollutants (POPs). As carbon-based compounds, they are highly resistant to degradation and they find their was into the ecosystem through electronic waste, burning fossil fuels, pesticides, herbicides, plastics, and pharmaceuticals. Other chemicals found lurking in the environment include DDT and Agent Orange – substances which can cause cancer, neurological disorders, birth defects, and reproductive damage.
Many POPs travel to the Tibetan Plateau and Himalayas from other regions on the wind. The compounds evaporate in hot areas and ride atmospheric currents until they are deposited in high, cold elevations. In 2008 a team led by Xu Baiqing, an environmental scientist at the Institute of Tibetan Plateau Research (ITP) in Beijing, documented DDT, hexachlorocyclohexanes (HCHs), and polycyclic aromatic hydrocarbons (PAHs) in the East Rongbuk Glacier near Mount Everest. Wang Xiaoping, an environment scientist at the ITP and lead author of the study said that levels correlated with human use of the chemicals. For example, the amount of DDT dropped in the 1970’s when European counties outlawed the compound, but rose again in the 1990’s when the Indian subcontinent began using chemical more frequently.
At the Third Pole Environment Workshop earlier this month in Dehradun, India Xu also reported that ice cores taken across the Himalayas and Tibetan Plateau showed high levels of POPs. They found that POPs in Western Tibet came by way of westerly winds from Europe and Africa, while those in the south were deposited by Indian monsoons and South Asia. The mountain communities (which do not use the chemicals) are facing the contamination of their ecosystems. The POPs accumulate as they move up the food chain, and human and animals populations are at risk – the issue could reach a critical threshold in the next few decades.