This type of assessment is common in the United States, usually taking into consideration the potential for direct human exposure (DHE) as well as leaching risk to water supplies. One approach when evaluating direct human exposure is to compare the elemental compositions of materials to risk based thresholds derived from toxicity data. Table 1 shows the Florida Industrial Soil Cleanup Target Levels, an example of a risk-based BMS-232632 contamination threshold; as shown in the table, certain elements (such as arsenic or lead) are present in a high enough concentrations in MSWI bottom ash that the DHE threshold would likely be exceed. In assessing the potential for an ash to contaminate a water resource (such as an aquifer) leaching tests are employed. In the U.S. complete dominance is common that risk thresholds for evaluation of leachate concentrations may be represented by the federal drinking water standards; this type of evaluation does not take into account the mobility of contaminants in the subsurface environment. Another approach is taken into account for the dilution of the leached water in the reuse scenario, and set limits which reflect the initial concentrations. This approach is taken in Denmark and The Netherlands, and will be discussed below.