This paper describes management options and interventions taken by the Government of Jordan to ensure that the quality of drinking water supplied to consumers via the Disi Water Conveyance Project (DWCP) meets Jordanian drinking water standards and WHO guidelines for drinking water quality in respect of their radiological composition. Results from an initial survey of radioactivity present in water abstracted from each of the 55 wells (which comprise the operational well field) indicated an average radiological dose of 0.8 milliSieverts per year (mSv/y) would be accrued by members of the population if consuming water directly from the well head. During full scale operation, the estimated accrued dose from the well field as a whole decreased to an average of 0.7 mSv/y which was still approximately 1.4 times the Jordanian reference radiological limit for drinking water (0.5 mSv/y). Following assessment of treatment options by relevant health and water authorities, blending prior to distribution into the consumer network was identified as the most practicable remedial option. Results from monthly sampling undertaken after inline blending support the adoption of this approach, and indicate a reduction in the committed effective dose to 0.4 mSv/y, which is compliant with Jordanian standards.

There is increasing concern about the effect of chemicals in the environment on the health of man, animals, crops and the sustainability of the Earth’s surface life support systems. Concern centres on heavy metals, arsenic, fluoride, radioactive substances and persistent organic pollutants (POPs). In humans such potentially harmful substances (PHSs) have been associated with various diseases including cancer. There is also increasing recognition that changes in the chemistry of the Earth’s surface as a result of human activity are having an impact on the environment at the global scale. In the context of these concerns, there is a serious lack of monitoring and information on the concentration and distribution of PHSs in the environment and little information on associated exposure and effects on people and ecosystems. High-resolution systematic digital geochemical maps are of value for addressing such problems at the national to local scale. Typically, a range of potentially harmful elements, radioactive elements and essential trace elements has been determined. The resulting data facilitate the understanding of complex environmental geochemical problems. Unfortunately, the geochemical data currently available have been obtained mainly in the absence of any international standards and there have been considerable differences in survey methodologies. To address these problems, the IUGS and IAGC have established a Global Geochemical Baselines Working Group. The aims are to prepare a standardised global geochemical baseline, to document environmental problems and to provide a means of monitoring future changes in surface geochemistry. Such information can be used to refine, develop and validate models for the interaction of man and the environment at the local to global scale. plots of 25 th , 50 th , 75 th and 90 th percentile total cerium concentrations in raw cassava and cassava dried on the ground, Uganda (Smith et al., 1998). The populations studied have a preference for eating soils derived from termite mounds. In vitro bioavailability (or strictly bioaccessibility) studies known as Physiologically Based Extraction Tests (PBET), were applied to different soil types. These tests mimic conditions in the human gut, and results revealed that several elements were more bioaccessible in termite soils than ordinary soils. The

This chapter contains sections titled: Introduction Hazardous properties Sources Environmental pathways Bioaccessibility and bioavailability Risk reduction References

A cultural transfer of geophagy is evident in the UK, with soils imported from Bengal being deliberately consumed mainly by pregnant Asian women. Two samples purchased from ethnic shops were subjected to a 2-part acid–alkaline in vitro physiologically based extraction test (PBET) procedure, representing the stomach and small intestine of the human digestive system respectively, to determine the bioaccessibility of elements. Despite the low bioaccessibility of Fe, with the quantity of soil consumed one sample can provide 41–54% of this mineral nutrient required by a 15–18 year old female, with the other sample providing 90–119%. Significant amounts of Ca, Cu and Mn are also supplied to the consumer, whilst further research investigating the possible effects of Pb toxicity on the geophagist would seem to be justified.

The impact of chemicals on the environment and human health is a cause of increasing concern. Although many studies continue to be carried out on this subject, most address only individual chemicals or particular groups of chemicals, such as metals or radioactive substances. In this paper, we consider the availability of data and knowledge about potentially harmful chemicals from the national to international scale and suggest a strategy to help prevent chemical pollution or deficiencies damaging global sustainability into the 21st century. The main groups of chemicals considered are:(i) Potentially harmful inorganic elements such as As, Cd, Hg and Pb known to have adverse physiological effects at low levels, and elements and species such as Se, I and NOx that can be essential or harmful depending on their concentration, speciation and bioavailability. Chemical elements such as Ga, In and the PGEs that are increasingly used in the development of new materials, including nanotechnology applications, are also discussed briefly.(ii) Radioactive substances, including naturally occurring radioisotopes, such as U-238 and its decay products Ra-226 and Rn-222, and processed materials, such as depleted uranium (DU), which affect the environment and human health because of their radiological and chemical toxicity. Data on isotopes from the nuclear industry, such as the relatively short-lived isotopes Cs-137 and Sr-90, are also discussed, including from accidental releases such as Chernobyl in 1986. Isotopes with longer half-lives such as Am-243 and Pu-240, which are important in the development of nuclear waste management strategies are also considered.(iii) Persistent organic pollutants (POPs) including many synthetic chemicals such as dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), flame retardants and their metabolites, which are characterised by their persistence, bioaccumulation (lipophilicity) and toxicity (PBT) properties. Other synthetic chemicals such as perfluorooctane sulphonate (PFOS), which have different bioaccumulation properties, are considered briefly.(iv) Human and veterinary pharmaceuticals, of which there is increasing evidence of their presence in the environment. These substances are of particular concern because many are designed to target specific biological receptors and hence can have potentially deleterious effects at exceptionally low concentrations.All these groups of chemicals include endocrine disrupting chemicals (EDCs), capable of disrupting animal and human hormone systems (including sex and thyroid).Geochemical databases such as those prepared by the Forum of European Geological Surveys (FOREGS) and the British Geological Survey (BGS) provide systematic information on levels of inorganic chemicals in the environment. Similarly, airborne radiometric databases provide systematic information on the distribution of radioactive substances. Examples of such data are used to demonstrate how the distribution of chemicals in the environment can be mapped, and how modelling and monitoring systems derived from them are of strategic importance in understanding the impact of chemicals on ecosystems and human health from the national to global scale. There is concern, however, about the lack of such systematic data for organic chemicals. It is argued that such systematic data for all chemicals is crucial for sustaining the Earth's life-support systems into the 21st century. (C) 2005 Institute of Materials, Minerals and Mining and Australasian Institute of Mining and Metallurgy.

The role of trace elements in human health and environmental pollution has developed into an extensive field of research. This study describes a sampling and analytical strategy to determine the trace element content of primary (deciduous) teeth and to assess their use in environmental health and nutrition studies. Exfoliated and extracted primary teeth were collected from 21 Ugandan and 27 UK children. The crown and root of the teeth were separated and the former digested and analysed for several elements by inductively coupled plasma mass spectrometry. The influence of country, tooth type, age and gender were statistically investigated in addition to within-person variation. A principal components analysis (PCA) was used to treat the data in a multivariate fashion and facilitated the moderation of outliers. The results demonstrated that country of origin has an important influence on the elemental composition of teeth and that tooth type should be controlled in these types of studies. Given such a restriction, the age and gender of the donor should have no effect and do not need to be controlled. In addition, where country of domicile, age and gender were controlled, the concentrations of most elements within a single tooth type were representative of an individual and therefore may be indicative of health status.

Land degradation and pollution caused by population pressure and economic development pose a threat to the sustainability of the Earth’s surface, especially in tropical regions where a long history of chemical weathering has made the surface environment particularly fragile. Systematic baseline geochemical data provide a means of monitoring the state of the environment and identifying problem areas. Regional surveys have already been carried out in some countries, and with increased national and international funding they can be extended to cover the rest of the land surface of the globe. Preparations have been made, under the auspices of the IUGS, for the establishment of just such an integrated global database.

The on-line determination of volatile and semivolatile organic compounds (SVOCs) is reported using membrane inlet mass spectrometry with in-membrane preconcentration (IMP-MIMS). Semivolatile organic compounds in aqueous samples are preconcentrated in a flow-through silicone hollow-fiber membrane inlet held in a GC oven. The sample stream is replaced with air, and the SVOCs are thermally desorbed into the mass spectrometer by rapid heating of the membrane. The method is evaluated for the on-line determination of 4-fluorobenzoic acid, 3,5-difluorobenzoic acid, 2-chlorophenol, p-tert-butylphenol, and dimethyl sulfoxide (DMSO) in water. The selectivity of the IMP-MIMS technique for SVOCs in the presence of VOCs is demonstrated. Cryotrapping and a rapid gas chromatographic separation step were added between the membrane and the mass spectrometer ion source for the determination of SVOCs in complex mixtures. The procedure is demonstrated for the determination of dimethyl sulfoxide (DMSO) in equine urine, using internal standardization with DMSO-d6. Full-scan electron ionization (EI) mass spectrometric detection showed good linearity (R = 0.998) and RSDs, relative to the internal standard, of 2.2% for desorption only and 4.6% for desorption and cryotrapping.

The UK Department For International Development (DFID) Technical Development and Research (TDR) programme funded a three-year project between 1995 and 1998 entitled “Cerium & Endomyocardial Fibrosis in Tropical Terrains” (Project R6228). The presence of elevated levels of dietary Ce, and deficient levels of dietary Mg in southern India have been assigned as potential environmental cofactors in the aetiology of Endomyocardial Fibrosis, which is also endemic in certain areas of Uganda. One of the aims of the project is to assess the relative importance of various exposure scenarios for the Ugandan population to Ce to define protective measures if required. Initial assessments of dietary intakes of Ce in Ugandan soils and foodstuffs have indicated that soils are a significant exposure pathway. A review is presented of exposure to soil and its ingestion both world-wide and specifically in Uganda. The deliberate consumption of soil by pregnant women and children (during the crawling stage of their development and between the ages of 4 and 8) is common in Uganda. However, prior to this study no information was available concerning the bioavailability of Ce in ingested soil or soil contaminated food. A Physiologically Based Extraction Test (PBET) has been used to determine the bioaccessibility of Ce in soil and dust samples from two districts in Uganda. The PBET incorporates gastro-intestinal tract parameters representative of a human for predicting the bioaccessibility of metals from an ingested solid matrix . Results showed there was a large degree of variation in Ce bioaccessibility between the samples, and between the different size fractions of individual samples. There was a marked increase in bioaccessibility when the pH was increased between the stomach and small intestine phases of the PBET for the smaller size fractions between >20 and <1 μm. Variations in mineralogy are considered to have caused the variations in Ce bioacessibility, although it was not possible to accurately determine specific mineral phases due to the small size of the minerals in the finest soil fractions.

Many minerals that are essential to human health in small doses can be toxic if ingested in excess. These minerals enter the human population via the plants, animals and water that make up our food supply and through the ingestion and inhalation of dusts derived from our living environment. Animals and plants depend ultimately on soil, water and rock for the provision of minerals hence the link between geochemistry and health. This link is particularly important in developing countries where people are often totally dependent on subsistence agriculture for their dietary needs. The inability of the local environment to provide the correct mineral balance can lead to serious health problems and disease.

The stream water hydrogeochemical database, produced by the Geochemical Baseline Survey (GBASE) of the British Geological Survey, has recently been enhanced in the light of experimental pilot studies in North Wales, to meet a wider range of economic and environmental objectives which require modern, integrated and strategic geochemical surveys for their implementation. Hydrogeochemical data are therefore now collected, in conjunction with geochemical data for stream sediments, soil samples and mineral concentrates. The density of sampling, based on the collection of stream water at near-baseflow conditions during the late summer period each year, has been increased to one site per 1.75 km(2) and a broader spectrum of geochemical determinants introduced. Provisional regional datasets are being prepared for an extensive region covering Wales, the Welsh Borders, and part of the West Midlands representing over 17 000 sample sites. Bedrock geology and base metal sulphide mineralisation are particularly well reflected in the stream water chemistry at the regional scale. The influence of secondary factors, such as geomorphology, atmospheric controls, and anthropogenic contamination due to agriculture, urban, industrial and military developments, can also be readily distinguished. The data obtained by systematic high resolution sampling of first and second order streams, vary in concentration over three or four orders of magnitude for many of the analytes studied here. This compares with a range of only one or two orders of magnitude for many of the analytes in stream sediment samples. The extended range in values for stream water is an important factor in the gridding, plotting and production of relatively stable maps. They are relatively unaffected either by short temporal changes in stream water flow, which are attributable either to storm events noted during the sampling campaign, or by annual differences between wet and dry summers in different years. This has enabled a series of robust surface hydrogeochemical maps to be prepared for analytical data collected during the summer sampling campaigns conducted annually from 1989 to 1994. These maps provide a unique source of synoptic baseline information for a wide range of economic and environmental applications especially, when combined with other geoscience datasets in a GIS environment. Copyright (C) 1996 Published by Elsevier Science Ltd