Almost ten years ago, IROS technical director published an article about the emerging contaminants (PFOS) when the contaminant was unknown to the public. Also, he critically reviewed and published the research results on Persistent Organic Pollutants (POPs) bioavailability, which was later used by the National Environmental Protection Council (NEPC) as the backbone to prepare the soil bioavailability measurement for NEPM review ; see page #20 please.
In 1997, David Natusch estimated the number of contaminated sites in Australia to be up to 100,000, with remediation costs possibly in excess of $2 billion per year (Application and development of contaminated site remediation technologies in Australia, ANZAC Fellowship Report to Department of Internal Affairs, Wellington, New Zealand and Department of Foreign Affairs and Trade). A particular group of pollutants, known as polycyclic aromatic hydrocarbons (PAHs), contribute to a number of these Australian contaminated sites and constitute a complex public health hazard; see page #18 please.
When quantifying exposure to POPs via incidental soil ingestion for human health risk assessment, it is assumed that 100% of the contaminant is bioavailable for absorption into systemic circulation. However, this assumption may overestimate exposure thereby influencing risk calculations. A variety of in vivo and in vitro methods have been developed in order to quantify POP bioavailability for exposure assessment. The authors review bioavailability assays utilizing animal models (in vivo), surrogate assays (in vitro) for estimating in vivo POP bioavailability, the validation of surrogate assays, and future research needs for POP bioavailability determination.
In this study, PAH biodegradation was assessed in historically contaminated soils collected from former manufacturing gas plant (MGP), wood preservation (WPS) and tram yard (TY) sites. Measured enhanced natural attenuation (ENA) endpoints were compared to bioaccessibility-based endpoint predictions (i.e. using non-exhaustive extraction or oxidation methodologies) to determine the suitability of previously published bioaccessibility–biodegradability models for predicting the efficacy of bioremediation.
The last 20 years has seen bioavailability emerge as an alternative indicator for determining the potential risk that chemical substances pose to environmental or human health. As such it is being increasingly accepted as a tool for decision making in risk assessment and site remediation, and is now regarded as a significant research area ; see page #16 please.
Calls for development of a new landfill site specifically to handle contaminated soil are being made, in light of concern that current arrangements and levies are posing as significant obstacles for brownfield redevelopment. “Similarly, any rise in the current cost of disposing of contaminated material will mean that many important housing developments, particularly within the inner metropolitan area, may not be viable” ; see page #24 please.
This work investigated the microbial degradation of polycyclic aromatic hydrocarbons (PAHs) in liquid and soil matrices and the influence of PAH bioavailability on biodegradation and ecological/ human exposure. These research themes were investigated using three PAH contaminated Soils collected from a former wood preservation site, a former manufacturing gas plant and a tram yard site in South Australia.