Prioritization of potentially contaminated sites: A comparison between the application of a solute transport model...

Numerous potential contaminated sites in China pose a substantial risk to human health and the local ecology. Thus, there is an urgent need to prioritize and further investigate potential contaminated sites and determine those that pose a threat in this regard. Newly developed by the Ministry of Ecology and Environment, the Risk Screening Method (RSM) scoring system is employed to assess soil and groundwater risk across China. In this study, the RSM is tested at a screening level and compared with the EPACMTP model, a solute transport model developed for the risk assessment of land disposal sites. First, a regional sensitivity analysis is conducted for EPACMTP model parameters, and those with significant sensitivity are compared with the risk indicators in the RSM. Second, 28 sites are evaluated by both prioritization methods in order to compare RSM risk scores and EPACMTP model simulations. Our results show that the RSM have similar risk assessing factors as EPACMTP model and its promising capability of prioritizing high-risk sites with very little available data. However, it does provide a conservative assessment, as risks at some sites are over-estimated, so further investigation is recommended for sites with high RSM risk scores. In addition, the initial screening should be documented by additional investigations at sites in order to prove the potential risk. The length of the period considered in the assessment has a great influence on prioritization results for heavy metals. As longer time scale will result in higher risk, its selection reflects the balance of current cost and future risk. The EPACMTP model provides a range of possible risks and can assess them within different timeframes. It is suggested to conduct further comparisons between the RSM and the solute transport models for sites from other areas, types of industries and more mobile compounds.