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[ISLAMABAD] Hydrogen fluoride emissions from brick kilns have been found to damage trees and crops in new studies conducted by an international team of scientists in the Peshawar area of northern Pakistan.
Peshawar has 450 brick kilns and hydrogen fluoride is also released by factories making aluminium, ceramics, and phosphate fertilisers.
Reporting their findings in the February issue of Environmental Pollution, the scientists from the Netherlands, Pakistan and the UK said despite the potential of high fluoride emissions to damage to crops, "the impact of these brick kilns on agricultural production and farmers' livelihoods in Asia is poorly understood".
The scientists looked out for visible signs of injury to leaves, such as burnt-looking tips, as well as the amount of fluorides and sulphur in the leaves of apricot, plum and mango trees. They also interviewed local farmers about their observations of tree injury in orchards.
More leaf injury and higher hydrogen fluoride levels were observed near brick kilns, which indicated that emissions from brick kilns were the main cause of tree damage, the report said. Interviews with farmers also suggested significant impact from crop damage on livelihoods, the study said.
Hamidullah Shah, professor and head of the agricultural chemistry department at the Agriculture University of Peshawar, who was part of the research team, told SciDev.Net that damage due to hydrogen fluoride was marginal in winters, but worsened as the weather warmed.
Muhammad Nauman Ahmad, assistant professor and Shah’s colleague, said that hydrogen fluoride could destroy 40-60 per cent of tree yields. The polluting gases enter leaves through tiny openings called stomata and damage cells, giving fruits a "squeezed" appearance, he said.
"Once Peshawar’s surroundings were ideal for farming but, now in the presence of 450 brick kilns, the story is entirely different," Nauman said.
Pervaiz Amir, an agriculture economist at the Asianic Agro-Development Institute, Lahore, explained that brick kilns were contributing to the brown clouds and smog that were increasing across Pakistan due to rapid industrialisation.
According to Amir, wheat yields were already declining due to changes in the environment and "could further decrease by 20-25 per cent in the 2012, reducing per capita income and national wealth".
Link to abstract in Environmental Pollution