Metal fractionation of cadmium, lead and arsenic of geogenic origin in topsoils from the Marrancos gold mineralisation, northern Portugal

The Marrancos gold mineralisation has a chemical assemblage of Fe–As–Se–Bi–Au–Ag–Te–(Cu–Pb–Zn–Sn–W). The −200 mesh of 144 topsoil samples was analysed by ICP–MS to determine total contents of 53 elements that include potentially harmful elements like Cd, As and Pb. The soil geochemistry shows that some trace elements occur in considerably high concentrations. On the basis of data for total metal concentrations, 10 topsoil samples were selected to carry out a metal fractionation study using a selective extraction method. A set of four leaches of increasing strength was used sequentially in the soil samples. Across the study area, there is some evidence of past mining and exploration activity, indicating that these soils may be locally disturbed. The shallow mineralised quartz veins were exploited for gold by the Romans. Several galleries were constructed during the 2nd World War, probably for the exploration of quartz–cassiterite–wolframite veins. However, the main mineralised body in depth was never explored. The results of metal fractionation show different partitions for the three elements. Total Cd concentrations in these soils are low, with a median value of 0.1 mg/kg. In average, 12% of total Cd is adsorbed by clays and/or co-precipitated with carbonates, and 19% is bounded to Fe–Mn oxyhydroxides. However, the low concentrations indicate that the metal does not represent an immediate risk to human health. For Pb, metal fractionation shows that, on average, 22% of Pb is adsorbed by amorphous Fe and Mn oxides, but the samples from the northern part of the area have the major fractions of Pb in soluble forms. The low probability of exposure in this part of the study area decreases the risk posed by this heavy metal. Total As concentrations in the Marrancos soils are extremely high. A large area has As concentrations above 1,000 mg/kg. For As, metal fractions in the sulphide phase vary between 84 and 98% in the studied samples. But one sample has 20% of total As in easily reducible forms, corresponding to a partial concentration of 1,800 mg/kg that has a high probability of being bioavailable. The most labile As forms occur at the southern part of the area, where the probability of exposure is higher and the risk of human health increases in the same order. From the three studied potentially harmful elements, As is certainly the element of concern.     

Radon exhalation from phosphogypsum building boards: symmetry constraints, impermeable boundary conditions and numerical simulation of a test case

Comprehensive understanding of (222)Rn exhalation from phosphogypsum-bearing building material and its accumulation in indoor air is likely to rely on numerical simulation, particularly if transient effects, three-dimensional domains and convection are to be included and investigated. Yet, experimental data and analytical results are helpful (if not crucial) as far as validation is concerned. Having in mind computational code simplicity and in the light of a recent experimental and theoretical report on (222)Rn release from phosphogypsum boards for housing panels, this paper presents and discusses an alternative testing set-up and the corresponding boundary conditions, namely one side of the panel bounded by impermeable wall. Although this is a new facility to be tested, the resultant steady-state one-dimensional diffusion-dominant analytical solution is shown to match the counterpart deduced in the aforementioned previous report, despite it relaxes the constraint of symmetry about the phosphogypsum board centerline, which is inferred in that prior experimental scenario. In addition, numerical results are conducted for a diffusion-dominant two-dimensional time-varying test case concerning (222)Rn accumulation in a closed chamber having an exhaling phosphogypsum board tightly placed at one wall.     

234U and 230Th determination by FIA-ICP-MS and application to uranium-series disequilibrium in marine samples

A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results.     

Distribution and possible source of trace elements in the sediment cores of a tropical macrotidal estuary and their ecotoxicological significance

The paper presents the first document regarding concentration, distribution and possible sources of selected trace elements (Cu, Fe, Mn, Zn, Cr, Co, Ni, Pb, Al, B and Ba) in core sediments (<63 micro particle size) from the lower stretch of Hugli (Ganges) estuary, northeast coast of Bay of Bengal by ICP-AES and EDXRF to evaluate geochemical processes influencing their distribution and possible environmental consequences. The levels of elements showed a wide range of variations in different core depths, in upper and lower intertidal zones as well as among three sampling stations. The most interesting feature of the study is the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 20-28 cm in upper littoral zone of the site located in the extreme downstream stretch of the estuary. Values of organic carbon showed very strong positive correlations with most of the elements as revealed by correlation matrix (r) values. The interelemental relationship revealed the identical behavior of element during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of untreated effluents originating from industrial, agricultural, and aquacultural sources as well as from domestic sewage along with the fishing and boating activities. The resulting compositional dataset was tested by principal component analyses and cluster analyses. Pollution load index (PLI) and index of Geoaccumulation (Igeo) revealed overall low values but the enrichment factors (EFs) for Pb were typically high for all the stations. The mean concentrations of Zn and to some extent Cu exceeded the Effects Range-Low (ER-L) values in the majority of the cases indicating that there may be some ecotoxicological risk to organisms living in sediments. The concentration of the trace elements reported in this work is useful as baselines for comparison in future sediment quality studies.     

Use and knowledge of fuelwood in three rural caatinga (dryland) communities in NE Brazil

The woody species known, used, and preferred as fuelwood were examined in three rural communities within the county of Soledade, Paraíba State, NE Brazil. Ethnobotanical information was collected using semi-structured interviews with more than 90% of the local households (55 adult residents; 31 women, and 24 males). The interviewees cited 36 plant species as fuelwoods, distributed among 30 genera and 15 families, in addition to two unidentified plants. The plant families represented by the largest numbers of species were Euphorbiaceae, Anacardiaceae, Mimosaceae, Caesalpiniaceae, Sapotaceae, and Fabaceae. The species Caesalpinia pyramidalis Tul. (“catingueira”) was cited with the greatest frequency in all three communities. Within the communities we found significant differences on the number of plants cited and actually used (p < 0.05), indicating that the residents knew more fuelwood species than they effectively harvest. The different distances from the communities to the urban centers were not related to differences on the use or the size of the stocks of fuelwood. Additionally, the study revealed that the communities examined still maintain a significant knowledge of the use of energy-providing plants in spite of the widespread use of liquefied petroleum gas (LPG). Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

A soil sampling intercomparison exercise for the ALMERA network

Soil sampling and analysis for radionuclides after an accidental or routine release is a key factor for the dose calculation to members of the public, and for the establishment of possible countermeasures. The IAEA organized for selected laboratories of the ALMERA (Analytical Laboratories for the Measurement of Environmental Radioactivity) network a Soil Sampling Intercomparison Exercise (IAEA/SIE/01) with the objective of comparing soil sampling procedures used by different laboratories. The ALMERA network is a world-wide network of analytical laboratories located in IAEA member states capable of providing reliable and timely analysis of environmental samples in the event of an accidental or intentional release of radioactivity. Ten ALMERA laboratories were selected to participate in the sampling exercise. The soil sampling intercomparison exercise took place in November 2005 in an agricultural area qualified as a “reference site”, aimed at assessing the uncertainties associated with soil sampling in agricultural, semi-natural, urban and contaminated environments and suitable for performing sampling intercomparison. In this paper, the laboratories sampling performance were evaluated.     

Transport of radiocesium in mycelium and its translocation to fruitbodies of a saprophytic macromycete

We present a new protocol to study fluxes of radionuclides and other xenobiotics in saprophytic fungi. This simple method has successfully been used to evaluate transport of radiocesium in hyphae of Pleurotus eryngii and its translocation to fruitbodies.     

Sustainable tourism development in remote regions? Questions arising from research in the North Kimberley,Australia

This paper is concerned with the sustainable development of a self-drive tourist destination in the remote region in Northern Australia. It first compares officially used data on visitor profiles to the information collected in the survey. Differences between data collected and available secondary data imply that tourism planning should include collection of region-specific tourism information to guide and mitigate potential environmental changes. Natural landscape features are the key attraction for visitors to the region. Visitor satisfaction levels with the current state of the destination are high. However, local residents reported perceived negative impacts of tourism, in particular on amenities and the ecology of the landscape. Visitors also reported behavior that might contribute to environmental impacts. Implications of the findings, in the context of future destination planning, are discussed.     

The use of the shanny Lipophrys pholis for pollution monitoring: a new sentinel species for the northwestern European marine ecosystems

The contamination of aquatic ecosystems by organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) is a matter of great concern. Mussels have been extensively used as sentinel species in a large number of monitoring programs. However, the use of bivalves as the sole species has some limitations, because they are not as responsive as fish to Aryl Hydrocarbon Receptor agonists. Hence, for many marine areas, there is the need to validate new sentinel fish species that can be used in the assessment of pollution by organic contaminants. The shanny Lipophrys pholis is an intertidal fish that combines many characteristics required in a sentinel species: is abundant and easy to catch, has a wide geographical distribution and restrict home range. After larvae recruitment to the intertidal rocky shores, they remain in the same area for the rest of the life-cycle, thus reflecting local pollutants exposure. In order to evaluate the species sensitivity to organic contaminants under field conditions, L. pholis were collected at six sites reflecting different degrees of anthropogenic contamination. The induction of two biomarkers extensively validated in the assessment of PAHs contamination ethoxyresorufin-O-deethylase activity (EROD) and Fluorescent Aromatic Compounds (FACs) was evaluated. In parallel, mussels were collected at the same locations and levels of 16 PAHs and selected heavy metals determined. Overall, the specimens collected in the urban areas showed a significant induction of EROD and FACs (up to a six-fold induction) if compared with the reference sites. Additionally, a positive correlation was observed between the biomarkers and PAHs levels in mussel tissues. Even though further validation is currently in progress, the available data indicate that L. pholis is responsive to organic contaminants such as PAHs, suggesting its future integration in monitoring programmes designed to evaluate the presence of these contaminants in European marine ecosystems.     

Radon concentration measurements in mofettes from Harghita and Covasna counties, Romania

In the Harghita volcanic range (Romania) there are many occurrences of dry CO(2) emanations, called mofettes. The emanating gas with high carbon dioxide content has a proved curative effect. The gas also contains important quantities of radon. Since the mofettes are used in curative purposes in several illnesses, in most of the cases without medical supervising, has been proposed to determine the radon activity concentration in some of the most frequented mofettes from Romania. The seasonal variations have also been monitored and were calculated the effective doses received by the patients during a cure. The radon activity concentrations' levels above the mofettes indoor air range between 548 and 10 717Bq/m(3) while within the gas pools' values between 3210 and 32 781Bq/m(3) have been measured. The effective dose received by the patients during a cure is between 0.0086 and 0.16mSv. No major seasonal variations of the radon activity concentrations levels have been pointed out so far in the studied mofettes.