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India’s notorious traffic pollution is no longer an urban malaise, its impact is now being felt 4,000 metres above sea level, in the Himalayas. 

Geologists have found high levels of sulphur from diesel emissions along the Manali-Leh highway that snakes through the northwestern Himalayas. 

Soil samples from four sites along the 480 km highway were tested for 10 heavy metals and sulphur among other chemicals. While the good news is that heavy metal contamination was found to be low, the soil had significantly high levels of sulphur (490–2033 ppm), which the scientists attribute to diesel exhaust from heavy traffic on this mountainous road. 

Indian diesel contains some of the highest concentrations of sulphur in the world and an estimated 70% of automobiles running on Indian roads use diesel, “and the Himalaya are no exception,” says the paper published in the latest issue of science journal Archives of Environmental Contamination and Toxicology. Approximately 50,000 vehicles run on this highway every year, most of which use diesel. While the majority of these vehicles transport fuel and supplies to Indian army outposts, an increasing proportion ferries tourists, the paper says. 

“The remote Himalaya of northwestern India is not pristine,” and diesel-run vehicles “have started to have a measurable impact” on soils along the highway, it adds. 

The authors caution that the accumulation of sulphur can cause soil acidification, “that would render the already small amounts of arable lands in the area unproductive.” Excessive sulphur can, besides, be toxic to humans and animals. 

“We measured incredibly high amounts of sulfur close to the highway. Some of those values are the highest ever reported in the literature and were likely connected to truck traffic,” said co-author Brooke Crowley, an assistant professor of geology and anthropology, University of Cincinnati. “At first glance, it’s easy to consider the region to be a pretty pristine place. But there are environmental impacts from humans.” 

With the likely increase of exhaust and sulphur in this region in the future, the paper recommends periodic monitoring of contaminant accumulation and human health along the Manali-Leh Highway and similarly remote areas around the world. 

“There is no doubt that increasing economic development will put more stress on environments all over the world, remote or not,” said lead author, Rajarshi Dasgupta, graduate student at the Department of Geology, University of Cincinnati.

Source:  The Hindu