“During research for the US-Pakistan ‘gold mineralisation’ project, hyper-spectral remote sensing and geo-chemical analyses were used besides field work,” says Shuhab Khan, associate professor of geology at the University of Houston.
“Although most of northern Pakistan is known to have gold deposits, the new findings in Astore (in the Gilgit-Baltistan region) are significant and need extensive research with a view to safe extraction,” Khan tells SciDev.Net.
The project that ends in March involves the National Centre of Excellence in Geology, University of Peshawar, Pakistan’s Higher Education Commission and the US Department of State. Significantly, it turned up evidence of extensive mercury contamination in the northern areas.
“Our research indicates high mercury concentrations in soils close to mining operations and particularly alarming contamination levels in people living around the Hunza river,” Khan says.
Mercury dissolves gold out of the ore, and when heated boils away leaving gold behind. Gold extraction using mercury continues along the banks of the Hunza, Gilgit and Indus rivers in the remote Gilgit-Baltistan region.
“Mercury cannot be destroyed, knows no boundaries and easily contaminates air, soil and water,” says Mehmood A. Khwaja, senior advisor at the Sustainable Development Policy Institute, Islamabad. “It pollutes the environment and negatively impacts human health.”
“A limited study conducted on 80 persons in the gold panning areas revealed mercury concentration in urine samples as high as 129 micrograms per litre,” says Khwaja. “The average for the group was 57 micrograms per litre in males and 68 micrograms per litre in females.
According to WHO standards published in 2003, human blood and urine must not contain more than 6 micrograms per litre and 50 micrograms per litre respectively.
Mercury can cause memory loss, impaired coordination and such ailments as Hunter-Russell syndrome and Minamata disease. The liquid metal is particularly harmful to young children and in advanced cases of mercury-poisoning the brain, kidneys and lungs are damaged.
Extensive studies will be required to determine the extent to which the population in the northern areas is affected by mercury contamination, Khwaja says.
Sardar Khan, associate professor of environmental science, University of Peshawar, tells SciDev.Net that Pakistan needs international collaboration and better technology to be able to extract gold safely.