Cadmium contamination of agricultural soils and crops resulting from sphalerite weathering.

The biogeochemistry and bioavailability of cadmium, released during sphalerite weathering in soils, were investigated under contrasting agricultural scenarios to assess health risks associated with sphalerite dust transport to productive soils from mining. Laboratory experiments (365 d) on temperate and sub-tropical soils amended with sphalerite (<63 μm, 0.92 wt.% Cd) showed continuous, slow dissolution (0.6-1.2% y(-1)). Wheat grown in spiked temperate soil accumulated ≈38% (29 μmol kg(-1)) of the liberated Cd, exceeding food safety limits. In contrast, rice grown in flooded sub-tropical soil accumulated far less Cd (0.60 μmol kg(-1)) due to neutral soil pH and Cd bioavailability was possibly also controlled by secondary sulfide formation. The results demonstrate long-term release of Cd to soil porewaters during sphalerite weathering. Under oxic conditions, Cd may be sufficiently bioavailable to contaminate crops destined for human consumption; however flooded rice production limits the impact of sphalerite contamination

Abandoned metal mines and their impact on receiving waters: A case study from Southwest England.

Historic mine sites are a major source of contamination to terrestrial and river environments. To demonstrate the importance of determining the significance of point and diffuse metal contamination and the related bioavailability of the metals present from abandoned mines a case study has been carried out. The study provides a quantitative assessment of a historic mine site, Wheal Betsy, southwest England, and its contribution to non-compliance with Water Framework Directive (WFD) Environmental Quality Standards (EQS) for Cd, Cu, Pb and Zn. Surface water and sediment samples showed significant negative environmental impacts even taking account of the bioavailability of the metal present, with lead concentration in the stream sediment up to 76 times higher than the Canadian sediment guidelines 'Probable Effect Level'. Benthic invertebrates showed a decline in species richness adjacent to the mine site with lead and cadmium the main cause. The main mine drainage adit was the single most significant source of metal (typically 50% of metal load from the area, but 88% for Ni) but the mine spoil tips north and south of the adit input added together discharged roughly an equivalent loading of metal with the exception of Ni. The bioavailability of metal in the spoil tips exhibited differing spatial patterns owing to varying ambient soil physico-chemistry. The data collected is essential to provide a clear understanding of the contamination present as well as its mobility and bioavailability, in order to direct the decision making process regarding remediation options and their likely effectiveness

Next generation ice core technology reveals true minimum natural levels of lead (Pb) in the atmosphere: insights from the Black Death

Current policies to reduce lead pollution in the air are based on the assumption that pre-industrial levels of lead in the air were negligible, safe or non-existent. This trans-disciplinary article shows that this is not the case, using ‘next-generation’ laser technology in climate science, in combination with detailed historical and archaeological records in as many as 7 languages, from all over Europe. We show that lead levels in the air have been elevated for the past 2000 years, except for a single 4-year period. This 4-year period corresponds with the largest known pandemic ever to ravage western Europe (the Black Death), resulting in a 40-50% reduction in population. This unprecedented historic population collapse was accompanied by dramatic economic collapse that halted lead mining and smelting, and related emissions in the air. This trans-disciplinary study is a collaboration led by Harvard University and the Climate Change Institute at the University of Maine, and researchers from the University of Heidelberg (Germany) and the University of Nottingham (UK). It uses next-generation technology and expertise in history, climate science, archaeology and toxicology, brought to bear in a highly detailed contribution to planetary health, with crucial implications for public health and environmental policy, and the history of human exposure to lead

Spatially Explicit Analysis of Metal Transfer to Biota: Influence of Soil Contamination and Landscape

Concepts and developments for a new field in ecotoxicology, referred to as “landscape ecotoxicology,” were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessment. The aim of this study was to investigate the spatial heterogeneity of metal bioaccumulation in animals in order to identify the role of spatially explicit factors, such as landscape as well as total and extractable metal concentrations in soils. Over a smelter-impacted area, we studied the accumulation of trace metals (TMs: Cd, Pb and Zn) in invertebrates (the grove snail Cepaea sp and the glass snail Oxychilus draparnaudi) and vertebrates (the bank vole Myodes glareolus and the greater white-toothed shrew Crocidura russula). Total and CaCl2-extractable concentrations of TMs were measured in soils from woody patches where the animals were captured. TM concentrations in animals exhibited a high spatial heterogeneity. They increased with soil pollution and were better explained by total rather than CaCl2-extractable TM concentrations, except in Cepaea sp. TM levels in animals and their variations along the pollution gradient were modulated by the landscape, and this influence was species and metal specific. Median soil metal concentrations (predicted by universal kriging) were calculated in buffers of increasing size and were related to bioaccumulation. The spatial scale at which TM concentrations in animals and soils showed the strongest correlations varied between metals, species and landscapes. The potential underlying mechanisms of landscape influence (community functioning, behaviour, etc.) are discussed. Present results highlight the need for the further development of landscape ecotoxicology and multi-scale approaches, which would enhance our understanding of pollutant transfer and effects in ecosystems

A technological history of the drainage of the Derbyshire lead mines.

The thesis traces the development of lead mining in Derbyshire, particularly the drainage, from Roman times. The ore deposits are principally contained within the Carboniferous Limestone and are heavily watered, so that as mining proceeded from about 1630, the orefield became pre-eminent for the construction of long drainage adits locally known as soughs. Examination of contemporary mining documents and printed sources, coupled with field evidence, both surface and underground, has demonstrated that both hard-rock excavation and ore extraction was dictated by the available technology rather than by geological consideration, though the easier excavation through shale was preferred where a potential advantage could be seen. No technical innovations can be traced specifically to the Derbyshire orefield. New ideas were sometimes adapted rapidly, but not comprehensively. The peculiar mining laws, together with a lack of concentrated capital investment, were largely responsible for local difficulties in taking up the new ideas. The lead miners' comprehension of the geology is examined. While a detailed local knowledge of the succession of strata is evident from about 1650, when veins were followed under the cover of shale, little evidence has been found to suggest any overall understanding of the stratigraphy of the whole orefield until the end of the 18th century. Otherwise veins were found by a combination of intuition and close observation. Drainage projects can be shown to be linked closely with the development of individual mining areas, and these together revealed the geology during the peak mining period of the mid-18th century. An appendix catalogues over 330 known or suspected soughs and includes brief notes on the history and geology of each

Atomic spectrometry update : environmental analysis

This is the twenty-second annual review published in JAAS of the application of atomic spectrometry to the chemical analysis of environmental samples. In the analysis of air, there is ongoing use of XRF techniques for the measurement of particles collected on filters. There is continuing interest in the determination of trace levels of mercury species in the atmosphere. Isotope ratio measurement protocols are attracting wider interest as a potential tool for source apportionment studies. In the analysis of plant and water matrices, elemental speciation protocols for elements such as As, Hg, Sb, Se and Sn continue to receive considerable attention. Portable XRF instruments are now attracting interest for the rapid analysis of contaminated soil. In the geochemical measurement arena, laser ablation continues to go from strength to strength in being adopted as a solid sampling tool and interest is expanding to its use for the in situ determination of isotope ratios. To support this technique, a number of institutes are now preparing the next generation of CRM standards that are being characterized at the required micrometre scale

Atomic spectrometry update : environmental analysis

This is the twenty-third annual review published in JAAS of the application of atomic spectrometry to the chemical analysis of environmental samples. This update refers to papers published approximately between September 2006 and August 2007. In the analysis of air, there has been an increased awareness of the need to collect and characterise ultrafines, i.e., particles below 100 nm in size, and such work is being facilitated by the development of real-time aerosol mass spectrometric techniques. In the analysis of plant and water matrices, elemental speciation protocols for elements such as As, Cr, Hg, Sb, Se and Sn continue to receive considerable attention, with particular interest being shown in the speciation of Se compounds in plant matrices. Laser ablation continues to go from strength to strength in being adopted as a solid sampling tool in geochemical analysis. Such work is being underpinned by increased knowledge of the ablation process and resultant transport and plasma effects coupled with developments in fs UV laser technology. This technique, in conjunction with multi-collector ICP-MS technology, is increasingly being used for the in situ determination of isotope ratios in geological samples. Feedback on this review is most welcome and the lead author can be contacted using the email address provided. Alternatively, readers are welcome to complete the on-line questionnaire at http://www.asureviews.org