ABSTRACT
Soil concentrations of metals and arsenic (As) elevated above background levels have raised considerable concern in restoration projects, particularly in the context of potential risks to human health. Certainly, there is no shortage of available regulatory documentation and guidance. Routes of transfer of pollutants from soil to receptor are the most critical part of risk assessment, but the extent to which bioavailability of metals and As is considered is variable. When taken into account, predictors and assays of lability, mobility, and bioavailability are well known to be of restricted ef’cacy in predicting uptake and impact on biota, largely due to differing soil types and environmental conditions. This means that broad generalizations and accurate interpretation of the risks posed by elevated and potentially toxic soil trace elements in soils are dif’cult, requiring consideration on the basis of each particular trace element, site, and environmental conditions. It also raises concern because expensive and inappropriate risk-based decisions may be taken to remove potential risk, for example, involving extensive but unnecessary site engineering. Indeed, justi’cation and securement of funding for
CONTENTS
Introduction ......................................................................................................... 473 Bioavailability ...................................................................................................... 474 Case Study ............................................................................................................477 Habitat Creation on Brown’eld Land.............................................................. 481 Conclusions .......................................................................................................... 481 References ............................................................................................................. 482
restoration or remedial actions may be entirely driven by mitigation of risk which itself is informed by a misguided interpretation of science.
