Mongolia is a water-scarce land-locked country, and available water resources are utilized for multiple purposes including irrigation, food preparation, drinking water for livestock and people. Limited data availability on water hygiene means that the related risks to public health are only partially understood. This is particularly problematic due to the widespread use of unimproved water sources such as surface water and water from simple shallow wells. Based on two field surveys in the Kharaa River Basin in spring 2017 and 2018, we assessed the presence and quantity of total coliforms (TC), fecal coliforms (FC), and E. coli bacteria in surface waters and wells and investigated potential linkages between temperature and hygiene. In the Kharaa River and its tributaries, TC concentrations averaged at a most probable number of (MPN) of 754 ± 761 per 100 mL and FC concentrations at an MPN of 31 ± 33. Only small and non-significant correlations between coliform concentrations and temperature were identified. Coliforms concentrations in wells were lower (average MPN for TC: 550 ± 1286, and for FC 58 ± 253). There was considerable variation between wells, with moderate but significant correlations between temperature and bacterial counts. Low water temperatures in April and May (just above freezing to less than 6.5 °C in wells and 7.5 °C to 14.5 °C in the river system) and the positive correlations between temperature and coliform concentrations particularly for well samples indicate that further warming is likely to increase the risks of microbiological water pollution. In the future, this should be complemented by modeling at a watershed scale. This should include the consideration of a trend towards stronger rainfall events, changes in livestock density, and urban sewage treatment and discharge, which are other likely drivers of changes in water hygiene.

The coarse ore storage (COS) facility is repeatedly identified by Oyu Tolgoi as a major source of dust that presented a significant risk to worker health and the environment. Dust monitoring and observations conducted since 2013 demonstrated high concentrations of airborne particulate that were likely to be exceeding air quality standards. Dust generation at the COS occurred from the discharge to the covered stockpile and resulted in fine particulate depositing on the ground surface surrounding the COS. A foam dust suppression system was added to the COS feed in November 2014, with observed and measured reduction in dust emissions. An analysis of dust-monitoring data indicates some reduction in airborne particulate as a result of the foam dust suppressant addition. However, the measured reduction is not as significant as is suggested from visual observation of the COS. Additionally, dust curtains installed in 2019 continue to manage dust at the COS facility. Moreover, we implement some operational mitigations at the facility, including area cleaning, watering, and keeping the COS stockpile to at least 70% capacity to minimise drop-down distances, thereby decreasing dust generation. The dust-monitoring dataset demonstrates the substantial positive impact the installation of dust curtains, and other mitigations, have achieved.