A proposed guideline for verifying the attainment of soil remediation for Taiwan

This paper proposes a technical guideline for evaluating the success of soil remediation efforts. Statistical methods have been emphasized because there is a practical need for decisions regarding whether a site has met a cleanup standard in spite of inherent uncertainty. Uncertainty arises because only small portions of the soil at the site can be sampled and analyzed while the decision for the entire site is solely based on the few samples available. To overcome this bias, statistical methods were designed to permit extrapolation of the results from a few samples in order to make a statement regarding the entire site. Our proposed guideline, being tested in four cases, can provide a technical interpretation of data analysis methods acceptable for verifying the attainment of a cleanup standard of soils media. The guideline includes four parameters: first, the concentration of every sample should be less than the control standard; second, the concentration of 97.5% probability of cumulative curve should not exceed the control standard; third, the median concentration of sampling should be below the monitoring standard; and fourth, the indicator of evenness for the remediation works should be less than two. In comparison with traditional methods, our proposed guideline is shown to be effective in verifying remediation results.