Abstract
Khaidarkan, Batken Province, Kyrgyzstan is home to one of the world’s largest and last primary mercury mines, which is currently operating at low capacity. Doctors without Borders (MSF) and the Ministry of Health of Kyrgyzstan (MOH) found that the Batken region has an elevated rate of non-communicable diseases (NCD) compared to the rest of the country; NCD can be caused by environmental pollution. A human health risk assessment (HHRA) was conducted to investigate heavy metal exposures. One project goal is to build local capacity for a long-term environmental monitoring program. Using a hand-held x-ray fluorescence spectrometer (XRF) for soil screening is faster and cheaper than reliance on bench-scale methods.
To find a mercury conversion factor between the XRF and the local MOH lab’s Lumex Versatile Zeeman Mercury Analyzer RA-915M with Pyrolyzer PYRO-915+ attachment, soil samples were collected in Khaidarkan and its outlying villages. Samples were analyzed by the XRF in three stages (\emph{in situ}, \emph{ex situ}-bulk, and \emph{ex situ}-sieved), and \emph{ex situ}-sieved samples were analyzed by the Lumex. Based on statistical analyses, \emph{in situ} readings can be used as a qualitative tool for screening, and a conversion factor of 1.7 was developed between \emph{ex situ}-bulk/\emph{ex situ}-sieved and Lumex results. QA/QC analysis confirmed that XRF i\emph{in situ} readings may be used as a screening tool for risk criteria based on Type I and Type II error rates. When \emph{in situ} results warrant collecting a physical soil sample, then the bulk or sieved soil sample can be measured by the XRF. Using the XRF to estimate the Hg concentration in soil, screening of a site can be conducted quickly and cost-effectively. Where mercury concentrations are found to be above the risk criteria, steps can be taken to reduce human exposure.
As gold prices continue to rise, mercury will continue to be in demand for use in artisanal and small-scale gold mining (ASGM). The Kadamjai Sanitary and Hygienic Laboratory (SHL) will need to continue to monitor for harmful Hg concentrations. Using the established conversion factor, SHL will be able to use the XRF as a quick and cost-effective screening and monitoring tool.