Health Risk Assessment of Groundwater in Shigatse Landfill Site of Tibet

[Objectives] The research aimed to grasp environmental quality of groundwater in landfill site, predict health risk of pollution factors to regional residents, provide scientific basis for landfill management, pollution prevention and control, and ensure safety of residents' drinking water supply. [Methods] Through on-site sampling of three groundwater monitoring wells at Shigatse landfill, and testing and analysis of conventional indexes and heavy metal elements, standard index method and comprehensive index method were used to evaluate environmental quality of groundwater in the landfill area. On this basis, a health risk evaluation model was applied to assess the health risk of residents in Shigatse landfill area. [Results] Comprehensive water quality was good in individual well of Shigatse landfill. Because NH3-N and Fe in the monitoring well exceeded class III standard of groundwater environmental quality in 2014, pollution of monitoring well was relatively heavy. The total carcinogenic risk of landfill groundwater for male and female was 1.855×10-6 and 2.238×10-6 respectively, exceeding the maximum acceptable level of carcinogenic risk for contaminants (1×10-6). Cr6+ should be paid attention to. Moreover, risk value of health hazard for female was generally higher than that of male. The total non-carcinogenic risk values for male and female were 0.057 7 and 0.069 6, respectively, far lower than the non-carcinogenic risk threshold of "1". [Conclusions] The groundwater environmental quality of Shigatse landfill site was good, and it posed little health risk to regional residents.