Air pollution from internal combustion engine vehicle use is altering the environment notably, even along the remote Manali-Leh Highway in the Himalaya Mountains in India, new research from the University of Cincinnati has found.
To be more specific, the researchers examined the soil along the 300-mile route to check for the presence of common exhaust pollutants (heavy metals, sulfur, etc.).
The route, which is along mostly dirt and gravel roads, passes through one of the highest mountain passes the world that can accommodate vehicles — at roughly 17,480 feet. It’s this quality that’s responsible for the highway’s status as a tourist destination (of sorts). The road, which is traversed by around 50,000 vehicles a year (mostly diesel trucks and buses), was completed in the 1970s.
Commenting on the findings, an assistant professor of geology and anthropology at UC by the name of Brooke Crowley stated: “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.”
Along with Crowley, UC graduate student Rajarshi Dasgupta was closely involved with the fieldwork involving the gathering of soil samples along the highway.
The press release provides more: “For the study, Dasgupta took soil samples at 4 places along the highway and at 6 prescribed distances, starting with samples literally on the dirt road and extending out 150 meters. Soil samples were collected at 3, 9, and 15 centimeters in depth.
“Dasgupta said villagers in this area burn wood and cow dung for cooking and heating their homes. The resulting smoke often contains polycyclic aromatic hydrocarbons, a known carcinogen. They tested the soil for these hydrocarbons along with sulfur, total organic compound and 10 types of heavy metal. This wide net was necessary to capture the myriad potential pollutants caused by truck traffic, Dasgupta said.
“The study found low levels of heavy metals and no relationship between their concentrations and distance from the highway. But they found high concentrations of sulfur, a major pollutant in the exhaust of diesel-powered engines.”
The relatively cheap diesel fuel used in most of India is, of course, particularly high in sulfur (hence the low price) — as is the case in many other poor parts of the world.
“At first glance, it’s easy to consider the region to be a pretty pristine place. But there are environmental impacts from humans,” Crowley noted.
That isn’t surprising, since even the deepest parts of the ocean are now home to high levels of human-created chemical pollution.
Discussing the fact that the highest concentrations of soil sulfur were found towards the bases of narrow ridges where trucks often have to idle while waiting to use a single lane during repair work, Crowley stated: “The road is terrible, and it’s almost always under construction. There can be lines of traffic idling waiting to go over the passes. Our results suggest that a fair amount of emissions accumulate in the soil.”
With regard to implications for the future, Dasgupta noted: “There is no doubt that increasing economic development will put more stress on environments all over the world, remote or not.”
The new findings are detailed in a paper published in the journal Archives of Environmental Contamination and Toxicology.
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