Environmental Geochemistry

Groundwater wells in the Amman-Wadi Es Sir
Aquifer (B2/A7) throughout Jordan are investigated for their
arsenic (As) and element-by-element geochemical behavior.
Groundwater wells are found to have total arsenic concentrations
above the recommended levels designated by the
Jordanian drinking water standard, the Environmental
Protection Agency of the United States, and the World
Health Organization. Arsenic distribution in the aquifer is variable,
but it is detected with a concentration of .10 ppb in 87
samples out of the analyzed 150 groundwater samples, with a
maximum concentration of 173 ppb. Elevated As concentrations
can be attributed to several mechanisms. One of these
mechanisms is accounted for to the interaction between
groundwater and the natural phosphorite deposits in the upper
part of the aquifer and oil shale deposits overlying it. The high
significant correlation between arsenic, phosphorus, and calcium
concentrations in the analyzed groundwater samples
suggest that these elements are derived from the same source.
Moreover, scanning electron microscopy shows the association
of As with the P and Ca in the phosphorite; pyrite is
present in the oil shale samples, which were collected from
the Muwaqqar formation overlying the aquifer. EDAX analysis
shows that substantial As concentrations are present in
phosphate and pyrite. This study suggests that the major
mechanism responsible for releasing As from the aquifer material
into the groundwater is a simple dissolution reaction.
However, Piper and Durov diagrams, correlation coefficients,
and factor analysis all suggest that water interaction with
phosphate and oil shale deposits, sorption of heavy metals,
and simple dissolution of iron oxyhydroxides are together
the primary factors affecting the chemistry of the groundwater
and responsible for the elevated As values in some wells.�

This study was conducted on the hydrochemistry of shallow groundwater and surface water in the Ndop plain, North West Cameroon. The objectives were to determine the physico-chemical characteristics of water, controls on water chemistry and suitability for drinking and irrigation. Forty-six shallow groundwater and 26 surface water samples were investigated. Field measurements of physical parameters were preceded by chemical analyses of the samples for major ions and F -. About 69% of the water sources had pH values below 6.5, classifying the water as barely acidic. Electrical conductivity (<282 µS/cm) and total dissolved solids (<183 mg/l) were low suggesting low-mineralised and freshwater. The relative abundance of major ions (meq/l) was Na 2+ >Ca 2+ >Mg 2+ >K + for cations and HCO 3 ->>NO 3 -≥Cl ->SO 4 2for anions. Major ion concentrations were low, and within the WHO guidelines for drinking water, but Fconcentrations were much lower (<0.39 mg/l) and below guideline value. Main water types and proportions were Na-HCO 3 (53 %), Ca-HCO 3 (35 %) and a mixed Na-Ca-HCO 3 (11%). Predominant processes influencing water chemistry were incongruent dissolution of silicate minerals and cation-exchange of Na + in rocks for Ca 2+ in water. The low major ion concentrations indicated low water-rock interactions and short residence time. The analysed water was suitable for irrigation.

Arsenic in dust and aerosol generated by mining, mineral processing and metallurgical extraction industries, is a serious threat to human populations throughout the world. Major sources of contamination include smelting operations, coal combustion, hard rock mining, as well as their associated waste products, including fly ash, mine wastes and tailings. The number of uncontained arsenic-rich mine waste sites throughout the world is of growing concern, as is the number of people at risk of exposure. Inhalation exposures to arsenic-bearing dusts and aerosol, in both occupational and environmental settings, have been definitively linked to increased systemic uptake, as well as carcinogenic and non-carcinogenic health outcomes. It is therefore becoming increasingly important to identify human populations and sensitive sub-populations at risk of exposure, and to better understand the modes of action for pulmonary arsenic toxicity and carcinogenesis. In this paper we explore the contribution of smelting, coal combustion, hard rock mining and their associated waste products to atmospheric arsenic. We also report on the current understanding of the health effects of inhaled arsenic, citing results from various toxicological, biomedical and epidemiological studies. This review is particularly aimed at those researchers engaged in the distinct, but complementary areas of arsenic research within the multidisciplinary field of medical geology.

Enargite, Cu 3 AsS 4 , is common in some deposit types, e.g. porphyry systems and high sulphidation epithermal deposits. It is of environmental concern as a potential source of arsenic. In this communication, we review the current knowledge of enargite oxidation, based on the existing literature and our own original data.

As drinking water is considered as a major pathway of exposure to fluoride in the human body, an endeavor has been made for the assessment of the non-carcinogenic health risk by using hazard quotient (HQ) of fluoride for males, females, and children separately in fluoride affected ground water areas of Indo-Gangetic Alluvial Plains. The study suggests that children groups are more prone to the non-carcinogenic risk of fluoride in the area as HQ for fluoride is more than unitary in 44% (Pre-monsoon) and 38% (Post-monsoon) samples respectively. Field survey conducted in fluoride-affected villagers of the study area portrays cases of mottling of teeth and bone deformities depending on the duration and dosage of fluoride consumption. Petrographic observations of host rocks coupled with molar ratios of chemical species studies exemplify that weathered material developed over the granite-gneiss, mica-schist, amphibolite, granitic intrusive and pegmatite veins due to weathering and extensive water-rock interaction resulting higher concentration of fluoride in groundwater. Likewise, the base exchange index (r1) and meteoric genesis index (r2) advocates that most of the samples belong to Na +-HCO 3 − type and meteoric origin respectively, and substantiate longer residence time of water along with solute acquisition processes are responsible for elevated fluoride in groundwater. It is, therefore, solar energy-driven electrolytic de-fluoridation technology ought to be provided on a priority basis to the affected inhabitants besides the implementation of rainwater harvesting schemes for mitigation/ dilution of elevated fluoride concentration. Several clinical studies and researches have been conducted to find out the impact of fluoride concentration in drinking water on human health. It is a well-known fact that fluoride (F −) at low concentration (<0.5 mg/L) induces dental caries, which enhances the risk of tooth decay 1,2. On the other hand, ingestion of excessive fluoride imparts adverse effect on human health 3. It is a well-established fact that elevated F − concentration in drinking water is linked to dental and skeletal fluorosis depending on the amount of intake and duration of exposure 4,5. Excessive fluoride can also damage structure, function and metabolism of soft tissues such as kidney, liver, lung and testicles 6-9. Various clinical studies suggest that ingestion of excessive fluoride promotes physiological dys-functions like mutagenesis, immune suppression, carcinogenesis and growth retardation 3,10. At times, higher concentrations of fluoride can also promote neuro-toxicological effects 11,12. Several studies indicate that exposure of excessive fluoride does impart the vulnerable effect on the mental ability of the children. Choi et al. 13 suggests that children with exposure to high fluoride were found with significantly lower IQ compared to children residing in low fluoride areas 13. Fluoride easily reaches the placenta, and exposure to fluoride may permanently harm the foetus 14. In the human body, the thyroid gland is the most sensitive tissue to the fluoride and exposure to fluoride raises TSH (thyroid stimulating hormone) concentration and decreases T 3 and T 4 concentration, thereby resulting in hypothyroidism 15,16. In several studies, it has been pointed out that prolonged exposure of fluoride from drinking water does develop insulin resistance in human beings 17,18. Excessive consumption of fluoride ultimately leads to hyperglycemia and impaired glucose tolerance 19,20. While some studies showed that exposure to high fluoride may induce adverse impact on human reproductive system, leading to infertility problems and low

Stawell Gold Mine in NW Victoria, Australia, mines ores that contain large concentrations of As and significant quantities of the metals Pb and Cr. The aim of this research was to understand the dispersion, enrichment and probable exposure of these potentially hazardous elements around the mine site. Fifty-five surface soil samples were collected near the mine (\15 km) and analysed by ICP-MS/ OES following bioavailable and four-acid extractions. Soils near the mine show greater concentrations of As, Cr and Pb than those near a regionally determined background. This is attributed to the combination of a natural geochemical halo around mineralization and anthropogenic dispersion due to mining and urbanization. Total As concentrations were between 16 and 946 mg kg -1 near the mine in a regional background of 1-16 mg kg -1 . Total Cr concentrations were between 18 and 740 mg kg -1 near the mine in a regional background of 26-143 mg kg -1 . Total Pb concentrations were between 12 and 430 mg kg -1 near the mine in a regional background of 9-23 mg kg -1 . Dispersion of contaminant elements from the present ore processing is \500 m. The most enriched soils occur close to the town and are unrelated to present mining practices. The bioavailable As, Cr and Pb, soil ingestion rates and Risk Reference Doses were used to estimate health risks. An average toddler (12 kg) would need to consume at least 1.5 g, and most likely 12 g, of soil per day to show some symptoms of As toxicity. The maximum measured bioavailable As would pose a risk at average ingestion rates of 200 mg per day. Individuals with soil-eating disorders would exceed the safe daily consumption limits for As, and potentially Cr and Pb. Small children are not typically exposed to soil everyday, very few have soil eating disorders, and, therefore, the health risk from the soils around the mine is minimal.

"The mega-site of Valencina is currently a major focus of interest for the study of Copper Age Iberia. Remarkable megalithic monuments such as La Pastora, Montelirio or Structure 10.042-10.049 at PP4-Montelirio are found alongside hundreds of other features, including pits and large-sized ditches, some of which have yielded evidence of exotic material craftsmanship without parallels in Iberian Late Prehistory which also suggests long-distance contacts. Part of the flourishing experienced by Valencina in the 3rd millennium BC can be explained by its specific geographic location at the mouth of the Guadalquivir river, facing a marine gulf surrounded by lands of high agricultural potential. Other reasons, however, must have accounted for Valencina's growth as a mega-site, including particularly demographic and economic ones. In order to better understand the demographic and subsistence patterns of the communities that lived and/or frequented Valencina, we analysed 29 human and 7 faunal samples for δ 18 O and δ 13 C isotope analyses. The sampling strategy followed is based on a combination of bone and dental tissues. In addition an intra-tooth study was also carried out to observe intra-individual seasonal changes. Overall, this evidence contributes to the study of diet and mobility patterns, which can in turn provide insights of the demography and economy of the communities that used this mega-site. "

In this study concentrations of selected metals viz., and Zn in surface soils of Sialkot city known worldwide for tanneries and pharmaceutical industries were measured to assess the status of urban soil pollution and to identify sources of contamination. Hierarchical cluster analysis (HACA) indicated concentrations of Mg and Ca related to parent rock material, Cd, Co, and Pb with traffic related activities, Cr, Cu, Ni and Zn either associated with automobiles activities or industrial pollution and Fe, K and Na related with anthropogenic activities or lithogenous materials. Correlation analyses and principal component analysis based on factor analysis confirmed the results of HACA. Spatial distribution maps exhibited relatively higher concentrations of Cd, Co, Cu, Ni, Pb, Cr and Zn along traffic routes in the city and streams. The results highlighted concentration of Cd, Ni, Cr, Zn, and Pb measured in urban soil exceeded the permissible limit of surface soils and advocated an imperative need for detailed baseline investigations of spatial distribution of heavy metals and other contaminants for the formulation of geochemical database that should be made available to stakeholder involved in monitoring, assessment and conservation of soil contamination for future planning and management of the Sialkot city.

The present paper deals with the issue of technogenic metallisation of mining site soils and the biosphere as a whole. The natural biosphere metallisation has probably started long ago. It is connected with the destruction of small areas with anomalously high content of metals in rocks and further migration of the released metals in the neighbouring biosphere areas. As a result, their content increases in a much larger area, although only slightly. This concentration increase can capture the pedosphere, hydrosphere, atmosphere, and living matter. As a result of deposit mining conducted by people, the enrichment of several biosphere parts with metals occurs much more intense and takes far greater areas than the natural metallisation. The metallisation began to have a negative impact on many living organisms, including humans. Therefore, the study and the role of this process from a purely geochemical moved into environmental. The investigation of topsoil pollution was conducted in mining areas of Russia, Kazakhstan, and Ukraine. The emission spectral analyses of thousands of samples showed that the dominant contemporary way of remediation at mining and beneficiation areas does not prevent a metal spread through the decades. The proposed insulation method allows preventing environmental pollution by using polyethylene and polypropylene wastes.