Arsenic and uranium contamination of Orog Lake in the Valley of Gobi Lakes, Mongolia: Field evidence of conservative accumulation of U in an alkaline, closed-basin lake during evaporation.

The shrinkage of inland, alkaline, and saline lakes has caused the elevation of arsenic and uranium concentrations in lake water. However, the chemical reactions associated with these enrichments remain unclear. We conducted a five-year study of the water chemistry of Orog Lake (Mongolia) and the chemical and spectroscopic characteristics of the sediment to determine the geochemical behavior of arsenic and uranium during evaporation. The arsenic and uranium concentrations increased as evaporation caused the lake to shrink. The maximum concentrations of arsenic and uranium exceeded 200 µg/L and 600 µg/L, respectively, when the lake area was the smallest. Comparisons of the monitoring results with predictions of geochemical modeling suggested that some arsenic was removed from the lake water under highly desiccated conditions. Sequential extraction and X-ray absorption near-edge structure analyses showed that ferrihydrite can take up As(V). The accumulation of uranium could be reproduced by considering only evaporation. The conservative behavior of uranium can be explained by the low affinity of U(VI) for carbonate and ferrihydrite at pH > 9 and high dissolved inorganic carbon concentrations. The ubiquitous formation of extremely soluble U-bearing salts after the complete desiccation of inland lakes may thus become a serious threat to limnetic ecosystems.

Ecological and Human Health Risk Assessment of Heavy Metal Pollution in the Soil of the Ger District in Ulaanbaatar, Mongolia.

The aim of the present study was to evaluate human health and potential ecological risk assessment in the ger district of Ulaanbaatar city, Mongolia. To perform these risk assessments, soil samples were collected based on reference studies that investigated heavy element distribution in soil samples near the ger area in Ulaanbaatar city. In total, 42 soil samples were collected and 26 heavy metals were identified by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) methods. The measurement results were compared with the reference data in order to validate the soil contamination level. Although there was a large difference between the measurement results of the present and reference data, the general tendency was similar. Soil contamination was assessed by pollution indexes such as geoaccumulation index and enrichment factor. Mo and As were the most enriched elements compared with the other elements. The carcinogenic and noncarcinogenic risks to children exceeded the permissible limits, and for adults, only 12 out of 42 sampling points exceeded the permissible limit of noncarcinogenic effects. According to the results of the ecological risk assessment, Zn and Pb showed from moderate to considerable contamination indexes and high toxicity values for ecological risk of a single element. The Cr and As ranged as very high ecological risk than that of the other measured heavy metals.

Evaluating the management effectiveness of protected areas in Mongolia using the management effectiveness tracking tool.

The importance of management increases in the context of numerous and intensive inner and outer pressures on Protected Areas (PAs). The need to assess the management effectiveness (ME) in protected areas is increasing around the world. The ME assessment helps to improve the management of PAs and to develop a rational, long-term action plan. This study was conducted using the World Wildlife Fund for nature (WWF) Management Effectiveness Tracking Tools methodology (METT) to evaluate the ME of six PAs in central and eastern regions of Mongolia. The main purpose of this study was to assess ME and identify common threats of PAs across different natural zones and administrative areas in Mongolia. The results of this evaluation indicate that, the main threats faced by PAs in Mongolia are: (i) degradation of ecosystems, (ii) environmental pollution, and (iii) habitat fragmentation, resulting from over-exploitation and inappropriate use of natural resources. All six PAs examined have clear management goals and management decision-making systems however, their ME scores differ significantly. This research suggests that the administrative features of the individual PA influence management effectiveness and problems in the efficient implementation of management still need to be resolved.