The effects of soil processes, related to the oxidation of sulphide sediments, on heavy metal concentrations in the soil and soil solution were investigated in a Norway spruce stand on a fine-textured, acidic soil rich in sulphates located on the isostatic land-uplift western coast of Finland. The age of the soil is ca. 300–400 years, and the soil texture is silt and till. The chemical properties of the soil and soil solution clearly reflected the formation of acid sulphate (AS) soil. Compared to background reference values for podzolic coniferous forest soil, the pH of the soil solution in the mineral soil (20–40 cm depth) was very low, and the Al, Fe and S concentrations extremely high. The Zn and Ni concentrations in the soil solution were also strongly elevated, and similar to the concentrations reported close to anthropogenic heavy-metal emission sources. The concentrations of Cd and Cu were also frequently elevated. In contrast, the acidity and metal concentrations of the soil solution sampled in the organic layer were not elevated. Similarly, exchangeable Zn and Ni concentrations were also elevated in the mineral soil, but not in the organic layer. Because Norway spruce has a very superficial rooting system and the zone with exceptionally high metal concentrations did not extend up to the topmost soil layers, sulphide-oxidation derived soil acidification is not likely to pose a serious threat to forest ecosystems growing on this type of site. Despite the elevated concentrations of protons and many metals in the mineral soil and soil solution (20–40 cm), the nutrient status of the spruce stand was satisfactory and the general health of the stand has been reported to be relatively good.

Former mining activities lasting 140 years in the Ducktown Mining District, Tennessee, USA, has contaminated the streams draining the district with acid-mine drainage (AMD). North Potato Creek and its major tributary, Burra Burra Creek, are two of the most heavily AMD-impacted streams in the district. The removal of dissolved metals from the water in these creeks is largely attributable to the sorption of Cu, Zn, Co, Al, and Mn on suspended hydroxide precipitates of Fe. The fraction of trace metals remaining in solution decreases with increasing pH in the sequence Pb < Cu < Zn < Co. The concentration of Fe in solution also decreases with increasing pH due to the formation of ferric hydroxide precipitates which accounted for up to 81.4% by weight of the total suspended sediment. The concentration of suspended sediment substantially decreases as the water of North Potato Creek flows through a large settling basin, where 1.3 (±0.3) x 10⁶ kg/year of trace-metal-laden suspended sediment would be annually deposited. In spite of this attempt to purify it, the water discharged into the river is acidic (pH 3.6) and still contains high concentrations of dissolved trace metals, which would resorb on to suspended sediment and be ultimately transported to a downstream reservoir, Ocoee No. 3 Lake.

An important component of monitoring pollution of urban road-deposited sediment (RDS) is an understanding of the temporal variability in its composition and physical characteristics. This study set out to determine what the monthly variability in metal concentrations, organic matter content, grain-size and grain-size fraction metal-loadings are in inner city sites in Manchester, northwest England. The results show that there is significant temporal variability in metal (Pb, Zn, Fe, Mn) concentration in RDS from inner city Manchester. There was no significant temporal variability in grain-size characteristics or organic matter content, indicting that these metal variations were the result of variation in sources and accumulation processes. Pb and Zn displayed local variability, suggesting local controls on variability, whereas Fe and Mn displayed consistent variability across all sites, suggesting a common, larger-scale control on variability. The finest grain-size fraction (<63 μm) contained the highest Pb, Cu and Zn concentrations, but for the case of Fe and Mn, the coarser fractions (>300 μm) commonly contained the highest concentrations, again suggesting differing controls. For all metals, due to the weight percent dominance of the coarser fractions, the dominant loading of metals is in the coarser fractions. This has implications on management strategies, via street sweeping and the subsequent waste disposal, and on the modelling of the input of RDS and associated metals into surface waterways. The recognition of significant temporal variability of metal concentrations in RDS, independent of grain-size changes, implies that the monitoring of urban road sediment pollution will require not just consideration of spatial variability, but the design of schemes that will capture temporal variability also.

The sources of copper topsoil variability in agricultural have been evaluated in the northeastern region of the Iberian Peninsula (Spain) using 624 soil samples collected in a standard 8 x 8 km grid. Analyses of variance combined with geostatistical methods have been used to map the spatial variability and to evaluate the relative contribution of natural and anthropic copper sources in topsoils. The use of the residual values derived from the interpolation method have led to the identification of local anomalies in the copper content in relation to agricultural practices carried out on the land. Copper concentrations were relatively low (17.33 ± 14.97 mg/kg) in areas with a high pH level (>8.2) and low organic matter (<1%). In general, the spatial distribution of copper showed a good relationship with the surface evidence of the lithologic units at a regional scale. At a smaller scale, concentration values also indicated the anthropogenic influence related to specific agricultural practices in relation to land use and cultivation methods. The highest mean concentrations were found in vineyards and olive fields. These were partly due to inputs from inorganic fertilisers, mainly copper sulphate, and also to the application of liquid and soil manure.

Heavy metal phytoextraction is a soil remediation technique, which makes use of plants in removing contamination from soil. The plants must thus be tolerant to heavy metals, adaptable to soil and climate characteristics, and able to take up large amounts of heavy metals. Most of the high biomass productive plants such as, maize, oat and sunflower are plants, which do not grow in cold climates or need intensive care. In this study three “weed” plants, Borago officinalis; Sinapis alba L. and Phacelia boratus were investigated for their ability to tolerate and accumulate high amounts of Cd and Pb. Pot experiments were performed with soil containing Cd and Pb at concentrations of up to 180 mg kg⁻¹ and 2,400 mg kg⁻¹ respectively. All three plants showed high levels of tolerance. Borago officinalis; and Sinapis alba L. accumulated 109 mg kg⁻¹ and 123 mg kg⁻¹ Cd, respectively at the highest Cd spiked soil concentration. Phacelia boratus reached a Cd concentration of 42 mg kg⁻¹ at a Cd soil concentration of 100 mg kg⁻¹. In the case of Pb, B. officinalis and S. alba L. displayed Pb concentrations of 25 mg kg⁻¹ and 29 mg kg⁻¹, respectively at the highest Pb spiked soil concentration. Although the Pb uptake in P. boratus reached up to 57 mg kg⁻¹ at a Pb spiked soil concentration of 1,200 mg kg⁻¹, it is not suitable for phytoextraction because of its too low biomass.

The rapid biodegradation of metsulfuron-methyl in contaminated soil was studied in this paper. The wheat (Triticum aestivum L.) rhizosphere was well simulated by setting up a hydroponic system that allowed the aseptic wheat root exudates flow onto columns containing soil previously contaminated with metsulfuron-methyl. The root-colonizing strain Penicillium sp. containing highly effective degrading plasmid on metsulfuron-methyl was inoculated in the soil, with the bulk and sterile ones as control. In soil from columns that received root exudates from a planted (versus an unplanted) apparatus, there was a significant increase in the growth of the tolerant fungi and the degradation of metsulfuron-methyl. On the other hand, the inoculation of Penicillium sp. also notably enhanced the degradation of the target herbicide. The extent of stimulation was more than twice of that measured in bulk soil. The fastest rate of disappearance of the xenobiotic occurred in the amended inoculated microcosms with 8.6 days of the half-life. The main types of low molecular weight organic acids and amino acids in the root exudates was determined to be oxalic acid, succinic acid and threonine, alanine, proline, methionine, lysine, isoleucine and leucine. What's more, by means of applying metsulfuron-methyl once again, the acclimated soil microorganisms with Penicillium sp. inoculation could sustainable rapid degrade metsulfuron-methyl. The results show that inoculation of the root-colonizing Penicillium sp. in wheat rhizosphere may be an effective approach for the rapid detoxification of soil metsulfuron-methyl contamination.

The use of numerical modeling in oil spill incidents is a well established technique that has proven to provide cost-effective and reasonable estimates of oil surface drift. Good predictability of such models depends highly on the quality of the input data of the incident and on the model calibration effort. This paper presents the results of simulating oil spillage trajectory in the Arabian (Persian) Gulf. The study employed a 3-D rectilinear hydrodynamic model combined with oil spill model. Typical representative environmental conditions of the Arabian Gulf were first setup into a hydrodynamic circulation model using data from various sources. The performance of the hydrodynamic model was then tested against measurements of tidal fluctuation and sea currents at selected locations. The spill analysis model was setup using the flow field produced from the hydrodynamic simulation and its performance was further validated against documented events of Al-Ahmadi historical oil spill crisis in the Gulf. The comparison of the actual and simulated oil spill drift was found reasonably acceptable allowing for further application in risk assessment studies in UAE Coastal water and in the entire Arabian Gulf as well.

A multi-media monitoring field investigation, which included atmospheric, road sediment and soil samples, was carried out at two highway study sites to identify past and present Pb sources. Past Pb anthropogenic sources such as paint and leaded gasoline were linked to significant Pb accumulation in roadside soils at both sites through Pb isotopic analyses. This was achieved by identifying the distinct Pb isotopic composition in older versus newer Pb accumulation at different depths across the soil profile. Older Pb accumulations exhibited lower ²⁰⁶Pb/²⁰⁷Pb isotopic ratios, consistent with Canadian Pb-bearing ores, whereas newer Pb accumulations reflected a mixture of the ²⁰⁶Pb/²⁰⁷Pb ratios of road sediment samples, with the Pb isotopic signature of uncontaminated soil. Isotopic analyses were also helpful in identifying road sediment as an important current source of Pb in roadside soils, by comparing the isotopic signatures derived from road sediment and atmospheric dustfall. The known association of Pb with anthropogenic sources was used to indirectly relate other metals (Cu, Mn, Zn) to the same source by the Enrichment Ratio method. Significant positive correlations at the 90-95% confidence level were found between Cu, Zn and Pb Enrichment Ratios in roadside and dust deposition samples. Weaker correlations were found between Mn and Pb, at the highway study site with the least amount of traffic. However, correlations between these two metals were significant at the 90% confidence level for the busier highway site highlighting Mn potential anthropogenic source. An isotopic tracer study is suggested to further investigate the process of Mn redistribution in the environment due to exhaust fuel emissions. More research is needed regarding the potential impact from using a Mn-based fuel additive.

In a step-by-step exercise - beginning at full greenhouse gas accounting (FGA) and ending with the temporal detection of emission changes - we specify the relevant physical scientific constraints on carrying out temporal signal detection under the Kyoto Protocol and identify a number of scientific uncertainties that economic experts must consider before dealing with the economic aspects of emissions and their uncertainties under the Protocol. In addition, we answer one of the crucial questions that economic experts might pose: how credible in scientific terms are tradable emissions permits? Our exercise is meant to provide a preliminary basis for economic experts to carry out useful emissions trading assessments and specify the validity of their assessments from the scientific point of view, that is, in the general context of a FGA-uncertainty-verification framework. Such a basis is currently missing.

The distributions and biogeochemical cycles of arsenic in the aquatic environment have captured the interest of geochemists due to arsenic's multiple chemical forms, the toxicity of certain arsenic species and large anthropogenic input. Seasonal variations in the dissolved inorganic arsenic concentration and speciation in Jiaozhou Bay, which is located on the west coast of the Yellow Sea in northern China, are presented here. Three cruises were carried out in Jiaozhou Bay under varying tidal regimes, one at neap tide and one at spring tide in August and one at spring tide in October of 2001. In addition to the transect surveys, the main sources of dissolved inorganic arsenate and arsenite in Jiaozhou Bay, including riverine input from five major tributary rivers, atmospheric dry and wet depositions, and groundwater and wastewater input, were collected in different seasons to estimate arsenic transport through different sources. The mean concentrations of total dissolved inorganic arsenic (TDIAs, As (V+III)) in Jiaozhou Bay were statistically comparable between summer and autumn, with higher concentrations at the northwest and northeast parts of the bay, reflecting human activities. The As (III)/TDIAs ratio ranged between 0.045 and 0.68, with an average of 0.16, implying that arsenate was the dominating species in Jiaozhou Bay. A preliminary box model was established to estimate the water-mass balance and arsenic budgets for Jiaozhou Bay, which demonstrated that river inputs and atmospheric depositions were the main sources of arsenic into Jiaozhou Bay. The concentrations of dissolved inorganic arsenic in Jiaozhou Bay have decreased in the last two decades. Compared with other areas in the world, the concentration of arsenic in Jiaozhou Bay remains at the natural level and this region can be characterized as a less disturbed area.