The highest mountains on Earth, the Himalayan Range had been contaminated by human activities even before the humans first climbed the range. Citing a study published in the journal PNAS, The Hans India said that the Himalayan glaciers have been intoxicated hundreds of years ago. According to the report, the researchers have found toxic metals that include chromium, zinc, nickel and cadmium in a much higher concentration than it naturally should have been. These were deposited around the year 1780, which also marked the beginning of the Industrial Revolution, the report said.
It also said that all the metals found in the glaciers are the byproduct formed when coal is burned, which was an important part of industries by the end of the 18th century. The research further stated that the particles were carried away from London (where the Industrial Revolution started) by winter winds and were deposited in the Himalayas.
Another speculation has been there for zinc deposits that it might be accumulated by large scale burning of forests which could be natural or have been there to clear forest in order to make way for farmlands. According to the report, there was a dire need to create more fields for agriculture which was eventually made by burning and clearing forests. However, according to researchers, it was difficult to analyse whether the glacial contamination (of zinc) came from a natural forest fire or human-made.
The study was done by analysing the ice core and the layers of ice formed between 1499 and 1992. The study also revealed that the contamination was intense in the 19th century. Meanwhile, humans reached the top peak of Mount Everest (29,029 feet) in 1953, which highlights that contamination was caused much before the mountain was climbed.