PubMed · 12920709
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Jeanne Beauchamp Hewitt. 2003. Hazardous exposure.. https://doi.org/10.1097/00000446-200308000-00006
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The common approach to performing quantitative risk assessments in the contaminated land industry in the UK lacks a formal methodology for the treatment of the full range of uncertainties and for documenting decisions regarding the development of conceptual models and the selection of computer codes. The approach presented here represents an alternative, more detailed, and systematic approach for developing conceptual models and addressing uncertainties when undertaking contaminated land risk assessments. It is intended that the advantages of this approach are recognised by practitioners in the contaminated land industry and adopted, where appropriate, to help improve the quality of contaminated land risk assessments. The identification of features, events, and processes (FEPs) has been applied to safety assessments of deep geological and near-surface disposal of radioactive wastes. One of the primary benefits of using this approach is in the development of conceptual models. The approach identifies the FEPs that need to be addressed during the development of conceptual models and in the selection of suitable computer codes that can be used to represent the conceptual models. This approach has been applied by BNFL at the low-level radioactive waste disposal site at Drigg in Cumbria and is currently being adopted for a contaminated land study at the Sellafield site, also in Cumbria. This paper presents the advantages of using FEPs in the development of conceptual models and the treatment of uncertainties. The paper also discusses the application of this approach to contaminated land studies and provides an example to demonstrate the application of the approach. BNFL's approach at the Drigg site involves the identification of components (features) and phenomena (events and processes) that govern interactions and dependencies between the components by arranging them in a matrix format.
Forty soil samples collected from central Jordan were analyzed by atomic absorption spectrophotometry for Pb, Cd, Zn, Cr, and Hg. The samples were also investigated for mineralogy using X-ray, electron, and optical microscopes. Sequential extraction procedures were used to predict the percentages of the Pb, Zn, Cd, and Cr present in each of the soil geochemical phases. The clay mineral assemblage encountered in the analyzed samples is composed of kaolinite, smectite, illite, and illite/smectite mixed-layer. The nonclay minerals of the sand-sized fraction are composed mainly of quartz and calcite as major minerals with pyroxene, biotite, and feldspars as minor minerals. The enrichment factors of the measured heavy metals Pb, Cd, Zn, Cr, and Hg in the clay fraction (<2 microm) of the collected samples are 3.1, 16.6, 1.5, 0.9, and 4.5, respectively. According to the index of geoaccumulation, the soils of the study area are considered to be moderately contaminated with respect to Cd, uncontaminated to moderately contaminated with respect to Pb, Hg, and Zn, and uncontaminated with respect to Cr. The measured metals correlated positively with the determined physicochemical factors such as pH, clay content, organic matter content, and carbonate content. The relatively high concentrations of Cd, Pb, and Hg in the soils of the study area are related to anthropogenic sources such as cement industry, fertilizers, and vehicle exhausts. It was found that Pb, Zn, and Cr are associated mainly with the residual phases and are relatively immobile. On the other hand Cd is enriched in the carbonate phase of the analyzed soil samples. It is possible to suggest the sequence of mobility for Pb, Zn, Cd, and Cr in the analyzed soil samples as the following: Cd>>Pb>Cr>Zn.
The International Society for Exposure Analysis (ISEA) and its Nomenclature Committee have been involved since the mid-1990s in an intermittent but ongoing effort to develop an official ISEA glossary. Several related activities have stimulated greater interest and discussion nationally and internationally on a common exposure language. Among these activities are a 1997 Journal of Exposure Analysis and Environmental Epidemiology feature article on exposure and dose definitions and a 1999-initiated project of the International Programme on Chemical Safety (IPCS) (WHO/ILO/UNEP) to confront terminology issues hindering harmonization in the area of exposure assessment. Recently, the ISEA members voted in support of adopting the IPCS glossary as the official ISEA glossary, and the ISEA Executive Board agreed to accept this recommendation. In this feature article, we (1) describe the process through which the ISEA adopted the IPCS glossary as the official ISEA glossary, (2) present the joint IPCS/ISEA glossary of terms and their definitions, and (3) discuss plans for how the glossary can be used by ISEA and updated over time by ISEA and IPCS. The glossary is intended to be a living document that reflects the latest usage and maintains international harmonization of exposure terminology that can be practically applied to improve communication in exposure and related fields.