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Following the high rate at which many drinking water sources are polluted globally, an adequate evaluation of the potential hazards posed by polluted water systems is essential. In Nnewi urban (southeastern Nigeria), inhabitants indiscriminately dispose municipal solid wastes into streams and rivers, thereby exposing the surface water quality to deterioration. The aim of this study was to assess the pollution status, ecological risks, and probabilistic health risks of surface waters in this area using integrated study approach. Several heavy metal pollution indices used in this study showed that the waters generally have low pollution. However, Pb was identified as the priority pollutant. Ecological risk assessment revealed that the samples pose low ecological risk. Furthermore, non-carcinogenic risk assessment revealed low chronic risk; but children are more exposed to chronic risk due to ingestion than adults. However, with respect to dermal contact, all the samples pose negligible risks to both populations, as their hazard indices were <0.1. The probability of cancer risk, when compared to the acceptable range of ≤1 × 10−6 to 1 × 10−4, revealed that many of the samples pose carcinogenic risk due to Pb ingestion to adults (75%) and children (100%). However, all the samples pose negligible cancer risk due to dermal contact. Water quality index revealed that majority (75%) of the samples are poor quality water, and thus not recommended for drinking purpose. Correlation and factor analyses showed that both geogenic and anthropogenic factors influence the presence of the analytes in the surface waters. [ABSTRACT FROM AUTHOR]

Protecting soil from Pb contamination has been a programme for a long time in China. However, research on lead pollution in wetlands remains rare. To understand the characteristics of Pb pollution in Beijing and the sources of contamination of different soil samples in wetlands, we collected samples during all four seasons from two soil horizons and analyzed their Pb concentrations and Pb isotope ratios. The average concentrations of Pb varied from 65.44 mg/kg in spring to 106.11 mg/kg in winter. Concentrations in autumn were significantly lower than those in spring and summer and were notably different between A and B Horizons (59.42 and 71.47 mg/kg, respectively). The Pb isotopic compositions show that Pb pollution results from a mixing of geogenic and anthropogenic materials. The ratios of 206Pb/207Pb and 206Pb/208Pb evidenced that coal combustion and vehicle exhaust are the main sources of lead contamination in the two horizons. These results will help in reducing lead contamination in soil by knowing the temporal and spatial variations and sources of lead in Beijing. [ABSTRACT FROM AUTHOR]

For the purpose of the nondestructive measurements of hazardous heavy-element-containing substances in soil samples, the emerging technique, triple-exposure X-ray computed tomography (CT), is proposed. The use of triple exposure (i.e. three different acceleration voltages for the X-ray tube) improves the accuracy of the identification of the atomic number of a heavy element. With lead as the target element, virtual X-ray microtomography simulations utilizing a polychromatic X-ray source accelerated at 70, 100, and 140 kV were performed. CT images for the three voltages were reconstructed on a computer for clayey soil samples with heavy-element-containing natural minerals, namely galena (PbS), witherite (BaCO3), stibnite (Sb2S3), sphalerite (ZnS), and magnetite (Fe3O4). Quantitative analysis of the reconstructed CT images was performed to obtain the following results. (i) Galena can be distinguished from other heavy minerals (i.e. witherite, stibnite, sphalerite, and magnetite). (ii) The lead content in the clayey soil can be estimated with reasonable accuracy. These successful results demonstrate that the triple-exposure CT technique is promising for the nondestructive characterization of soil samples contaminated with hazardous heavy elements such as lead. [ABSTRACT FROM AUTHOR]

The aims of this study were to explore the status of pollution and the temporal/spatial distribution of indoor and outdoor dust-Pb in the city of Kerman (SE Iran), located in a dry playa and arid climatic zone. Flat panes were laid at appropriate locations, in the indoor and the outdoor spaces of selected one-story houses in different areas of the city, to collect dust samples. Forty-two samples were taken and analyzed using the ICP-MS method. The measurements have shown that the outdoor dust-Pb concentrations varied from 23.7 to 275.2 mg kg−1, with a mean value of 71.8 mg kg−1, and indoor dust-Pb concentrations ranged from 47.6 to 150.2 mg kg−1, with a mean value of 89.6 mg kg−1. Based on these measurements, Pb was enriched in the outdoor and the indoor dust samples up to 48.8 and 29.4 times, respectively. Dilution, as a result of prevalence of geogenic dust in the outdoor space, is expected to be the main cause of the temporal differences. This study has shown that the eastern part of the city is more polluted compared to the other parts, and, because of the stable air conditions, the concentration of Pb in the summer dust is higher than the other seasons. [ABSTRACT FROM AUTHOR]

Lead contamination is a significant health hazard in communities around the world, but this environmental toxin often remains unknown to residents living near hazardous sites. This research investigates a unique case where residents were informed of lead contamination but rejected official and scientific narratives regarding environmental risks. The case study involves a decommissioned smelter in Colorado. Drawing from data collected over three years, the researchers examine how officials and experts communicated the severity of environmental health hazards. Despite these efforts, residents opposed the Environmental Protection Agency’s attempts to place the site on the National Priorities List for federal cleanup. The government’s framing of science and environmental risk failed to resonate with homeowners, despite the known and significant scientific evidence confirming environmental health hazards, and residents’ perceptions of lead contamination were mitigated by material concerns, including property values and community stigma. Implications for future research on lead contamination, environmental risk, and trust in science are discussed. [ABSTRACT FROM AUTHOR]

At the turn of the millennium, inhabitants of a small Karen village situated in one of Thailand's UNESCO World Heritage Sites sought access to environmental justice in the Thai courts over industrial pollution that had contaminated their local stream with lead and caused them years of degraded health and social misery. The Karen villagers were only able to gain access to justice with the help of NGOs that served them as a support group during a period when Thailand was experiencing active civil and democratic awakening. The NGOs, which had a common cause with the Karen villagers, helped them enter the 'environmental justice frame' and its discourse. Their experience of lead pollution was framed within a moral 'rhetoric of exposure', which came to guide their activism against intransigent agencies and policies, as well as their mobilization for access to justice. [ABSTRACT FROM AUTHOR]

This study examined the dissolution release performance of slow-release phosphate glass (SRPG), and the role this element plays in water and soil contaminated with heavy metals. It is known that the rate of dissolution ternary phosphate glass asXMgO–(50-X)Na2O–50P2O5(mol %) may be controlled by adjusting its content of MgO. The results showed that SRPG was uniformly dissolved in deionized water. Acidic or basic conditions induced the dissolution of SRPG; in contrast, lysate of SRPG in water decreased its rate of dissolution. Phosphate glass treatment of heavy metal lead (Pb)-contaminated soil effectively reduced the Pb content in H2O and MgCl2extracts by 81.6% and 75.7%, respectively. Comparative tests showed that leaf and root portion of Pb uptake in cabbage grown in soil treated with SRPG was reduced by 65.1% and 51.6% compared to untreated soil. Analysis of SRPG with Pb immobilization in water and soil environment by X-ray diffraction demonstrated that low-solubility phosphate (PbHPO4) and hydroxyphosphate [Pb5(PO4)3OH] complex was formed. Data indicate that SRPG may be effective in removal of Pb from contaminated soils and diminish risk of toxicity from ingestion of this heavy metal by consumers. [ABSTRACT FROM PUBLISHER]

The British lead mining industry peaked and declined well before environmental protection and aftercare became a statutory requirement in the post-war period, and as a consequence left in its wake pockets of barren and degraded land. Metal-rich waste tips rarely return to vegetation, and environmental pollution continues through wind erosion and adit drainage. Yet the upland and often remote situation of the mines has permitted many of these small scattered wastelands to escape extensive remediation. These abandoned mine sites have often been interpreted in terms of their historic economic and technological narratives or studied in relation to contemporary heavy metals pollution and current risks to public health. This interdisciplinary study explores the value and benefits of integrating these two approaches towards a better understanding of mining landscapes in relation to their pollution history; grounding the methodology in research questions rather than in any specific discipline. It combines the history of a small abandoned lead mine at Tyndrum, Stirlingshire, with the environmental record contained with the soil material at the site. The integration of traditional historical research with geo-scientific analysis both expands, and not only deepens, knowledge of the historic processes that have brought the specific landscape at Tyndrum to its current state of degradation but also sets the long-term environmental legacies of historic mineral exploitation in the wider British context. [ABSTRACT FROM AUTHOR]

The most typical enhancement for electrokinetic remediation (EKR) involves the neutralization of the alkaline front generated at the cathode by the addition of an acid to the catholyte. Although the use of strong and weak acids can be found in the literature, there is still a clear lack of reliable comparisons between them. This paper presents a comparison of the results obtained for a real lead contaminated soil treated by EKR enhanced with nitric or with acetic acid. The divergences that are usually observed in those experimental results obtained when using constant voltage drop are avoided here by the use of EKR with constant current intensity and the disposition in series of the soil lab columns. Important differences are observed in the behavior of the system when the acid was changed. The time needed to achieve the same metal recovery is more than 3 times longer for the nitric acid. A standard sequential extraction procedure was used to fractionate the lead concentration in the soil according to its mobility in a before- and after-treatment way. Regardless of these important differences observed in the remediation time, the fractionation results after the experiments were almost the same for the two acid enhanced EKRs. [ABSTRACT FROM AUTHOR]

In this study, the effects of lead on filtration rate of zebra mussel (Dreissena polymorpha) together with the accumulation of lead in the soft tissue of the mussels, were investigated. Studies showed different effects of lead in all concentrations. In three concentrations of lead (2, 48, and 93 µg L-1), no significant differences were investigated between filtration rates of mussels in treatments and also between treatments and control (respectively 102, 93, and 84% of control). Whilst, at concentration 455 µg L-1 the filtration rate of mussels decreased to 40% compared to control. In this study mussels in different lead treatments had the same exposure time, length range, and temperature. Therefore, in this experiment accumulation of lead in the soft tissue of the mussels is affected by the differences at lead concentration in treatments. Initial concentration of lead has a direct effect on its accumulation in the tissue of the mussels. In the highest concentration of lead, the most accumulation of lead in the soft tissue of mussels was observed and in the lowest concentration of lead, the least accumulation of lead in the soft tissue of mussels was found. [ABSTRACT FROM AUTHOR]

In order to assess the amount and distribution of lead pollution in soils in Belize City, Belize, seventy-five samples were collected from three distinct areas around the city (roadsides, houses, and playgrounds and schools). This study has provided data to establish the first soil lead database for Belize City, Belize. The soil samples generally exhibited pH values above 7, less than 18% organic matter, and more than 50% sand was found in 92% of the samples. These physical and chemical characteristics prevent the lead from accumulating in the upper layers of soil. However, high or hazardous levels were found in all sample categories. In the schoolyards and playgrounds category, the levels range from 3 ppm to 780 ppm, and average 131 ppm. The roadside samples had a range of 3 ppm to 5450 ppm, and average 445 ppm. The housing samples had the highest concentrations, with the range from 9 ppm to 104, 500 ppm and an average of 638 ppm. The geographic distribution of lead within the city appears to be somewhat random, although the most contaminated areas are generally in the south part of the city. The distance to potential source of contamination, for example peeling paint or a road, affects lead concentration, as does percent of organic matter in the soil. The physical characteristics that normally aid in the retention of lead in soil are not generally present in Belize City; however, the lead levels are dangerously high. [ABSTRACT FROM AUTHOR]

This study examined the extent to which the potentially toxic lead particulates emitted from motor vehicles are absorbed by competitive cyclists. A time trial (n = 5), a road race (n = 5), and a sedentary control group (n = 5) were examined with respect to blood lead (PbB) levels. In the two cycling groups, the PbB levels were measured before and after (1) a time trial (80km) held on a dual carriageway; and (2) a road race (120km) which took place in a rural area. Mean (± SE) resting PbB levels for the sedentary subjects, time trialists, and road racers were 0-442 ± 0041, 0-490 ± 0111 and 0-384 ± 0061 μmoll−1 respectively (p > 005). Mean post-race PbB levels of the time trialists (0-528 ± 0046μmol1minus;1 ) and road racers (0-346 ± 0-024 μmol1minus;1 ) did not differ significantly from the pre-race levels (p > 0-05). However, after their respective races, the mean PbB level of the time trialists was higher than that of the road racers {p < 0-05). Ninety minutes of cycling (70% VO2max) in a laboratory containing approximately 1μgm3 of airborne lead did not affect blood lead levels. All PbB levels complied with EC regulations regarding lead exposure. Despite a positive relationship between the amount of training and the PbB levels (r = 0-64, p < 0-05), competitive cyclists did not evidence abnormal levels of lead absorption. Time trialing on dual carriageways was associated with higher PbB levels than road racing. Further research should examine the PbB levels of a larger sample of competitive cyclists. [ABSTRACT FROM PUBLISHER]

Lead concentrations have been determined in air, soil and vegetationsamples taken along a major boulevard in Sofia town. Concentrations of total suspended particles (tsp) were also measured. The following concentrations have been found: tsp - 0.168/1.242 mg/m3; Pb aerosols - 0.00058=0.00573 mg/m3; Pb in soil - 16.2/184.3 mg/kg; Pb in grass - 2.6/27.4 mg/kg. Tsp concentrations as well as Pb concentrations in air, soil and vegetation correlated negatively with distance to the road. Airborne particle Pb is the main source forsoil and vegetation pollution. Sequential extraction showed that Pb was bound predominately to CO32- and only in a small quantity to easily exchangeable phase, to iron and manganese oxides and to organic matter. The results showed that Pb concentrationsin soil meet. the maximum permissible concentrations, except for the5-10 meters adjacent to the road. However, a possibility exists for Pb accumulation in soil. Planting suitable vegetation and promoting use of unleaded fuel can be proposed as measures to be taken. [ABSTRACT FROM AUTHOR]