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Chelating agent-assisted electrokinetic removal of cadmium, lead and copper from contaminated soils
2009
Giannis, Apostolos | Nikolaou, Aris | Pentari, Despina | Gidarakos, Evangelos
An integrated experimental program was conducted to remove Cd, Pb and Cu from contaminated soil. The chelate agents nitrilotriacetic acid (NTA), diethylenetriamine pentaacetic acid (DTPA) and ethyleneglycol tetraacetic acid (EGTA) were used as washing solutions under different pH conditions and concentrations. Results showed that the extraction efficiency for Cd in decreasing order was NTA > EGTA > DTPA, while for Pb and Cu it was DTPA > NTA > EGTA. The use of higher chelate concentrations did not necessarily result in greater extraction efficiency. Electrokinetic remediation was applied by conditioning anolyte–catholyte pH to neutral values in order to avoid any potential alterations to the physicochemical soil properties. The removal efficiency for Cd was 65–95%, for Cu 15–60%, but for Pb was less than 20%. The phytotoxicity of the treated soil showed that the soil samples from the anode section were less phytotoxic than the untreated soil, but the phytotoxicity was increased in the samples from the cathode section. Cadmium, lead and copper were extracted from contaminated soil by integrated electrokinetic and soil washing studies.
Показать больше [+] Меньше [-]Source identification of copper, lead, nickel, and zinc loading in wastewater reclamation plant influents from corrosion of brass in plumbing fixtures
2009
Kimbrough, David Eugene
A natural experiment indicated that a link between the presence and concentration of four elements, copper, lead, nickel, and zinc in the influent to two wastewater reclamation plants to the presence and concentrations of the same four elements in the tap water of residential properties. There were 36 populations of results that were assessed for the normality of their distribution, the difference in their median concentrations, the similarity in the ratios of their median concentrations, and the correlations of the concentrations. The results of this study suggest that brass corrosion is the major source of these four elements in the water reclamation plants influent and that there are two distinct populations of brass sources, those in the early stages of dezincification where the release of the non-copper elements is dominant and those in the later stages where the release of copper dominates and the type of brass that is corroding. Statistical analysis of residential tap waters and water reclamation plant influent showed that metals found in both came from brass corrosion.
Показать больше [+] Меньше [-]Air quality for metals and sulfur in Shanghai, China, determined with moss bags
2009
Cao, Tong | Wang, Min | An, Li | Yu, Yinghao | Lou, Yuxia | Guo, Shuiliang | Zuo, Benrong | Liu, Yan | Wu, Jiming | Cao, Yang | Zhu, Zhirui
In order to better understand the spatial and temporal distribution pattern of metals and sulfur present in Shanghai, moss bags with Haplocladium microphyllum (Hedw.) Broth. were suspended at 14 local monitoring stations from April through June 2006 in Shanghai, the largest city in China. The results showed that the concentrations of S, Cu, Pb, and Zn in the moss bags after exposure were higher at the sites in the industrial district and most urban districts and lower at the sites in suburban areas, and well correlated with SO2 API and PM10 API in the air both in terms of space and time. The present study provided evidence that the moss H. microphyllum is suitable for bio-monitoring air pollution with moss bags and further confirmed that the moss-bag method is a simple, inexpensive and useful technique. The moss Haplocladium microphyllum is suitable for bio-monitoring air pollution with moss bags.
Показать больше [+] Меньше [-]Study of lead phytoavailability for atmospheric industrial micronic and sub-micronic particles in relation with lead speciation
2009
Particles from channelled emissions of a battery recycling facility were size-segregated and investigated to correlate their speciation and morphology with their transfer towards lettuce. Microculture experiments carried out with various calcareous soils spiked with micronic and sub-micronic particles (1650 ± 20 mg Pb kg-1) highlighted a greater transfer in soils mixed with the finest particles. According to XRD and Raman spectroscopy results, the two fractions presented differences in the amount of minor lead compounds like carbonates, but their speciation was quite similar, in decreasing order of abundance: PbS, PbSO4, PbSO4·PbO, α-PbO and Pb0. Morphology investigations revealed that PM2.5 (i.e. Particulate Matter 2.5 composed of particles suspended in air with aerodynamic diameters of 2.5 μm or less) contained many Pb nanoballs and nanocrystals which could influence lead availability. The soil-plant transfer of lead was mainly influenced by size and was very well estimated by 0.01 M CaCl2 extraction. The soil-lettuce lead transfer from atmospheric industrial sub-micronic and micronic particles depends on particle size.
Показать больше [+] Меньше [-]Effects of inorganic lead on Western fence lizards (Sceloporus occidentalis)
2009
Salice, Christopher J. | Suski, Jamie G. | Bazar, Matthew A. | Talent, Larry G.
Although anthropogenic pollutants are thought to threaten reptilian species, there are few toxicity studies on reptiles. We evaluated the toxicity of Pb as lead acetate to the Western fence lizard (Sceloporus occidentalis). The acute lethal dose and sub-acute (14-day) toxicity studies were used to narrow exposure concentrations for a sub-chronic (60-day) study. In the sub-chronic study, adult and juvenile male lizards were dosed via gavage with 0, 1, 10 and 20 mg Pb/kg-bw/day. Mortality was limited and occurred only at the highest dose (20 mg Pb/kg-bw/d). There were statistically significant sub-lethal effects of 10 and 20 mg Pb/kg-bw/d on body weight, cricket consumption, organ weight, hematological parameters and post-dose behaviors. Of these, Pb-induced changes in body weight are most useful for ecological risk assessment because it is linked to fitness in wild lizard populations. The Western fence lizard is a useful model for reptilian toxicity studies. The Western fence lizard, Sceloporus occidentalis, is sensitive to Pb and is a useful laboratory model for ecotoxicological testing of reptiles.
Показать больше [+] Меньше [-]Modelling the risk of Pb and PAH intervention value exceedance in allotment soils by robust logistic regression
2009
Soils of allotments are often contaminated by heavy metals and persistent organic pollutants. In particular, lead (Pb) and polycyclic aromatic hydrocarbons (PAHs) frequently exceed legal intervention values (IVs). Allotments are popular in European countries; cities may own and let several thousand allotment plots. Assessing soil contamination for all the plots would be very costly. Soil contamination in allotments is often linked to gardening practice and historic land use. Hence, we predict the risk of IV exceedance from attributes that characterize the history and management of allotment areas (age, nearby presence of pollutant sources, prior land use). Robust logistic regression analyses of data of Swiss allotments demonstrate that the risk of IV exceedance can be predicted quite precisely without costly soil analyses. Thus, the new method allows screening many allotments at small costs, and it helps to deploy the resources available for soil contamination surveying more efficiently. The contamination of allotment soils, expressed as frequency of intervention value exceedance, depends on the age and further attributes of the allotments and can be predicted by logistic regression.
Показать больше [+] Меньше [-]Uptake kinetics of metals by the earthworm Eisenia fetida exposed to field-contaminated soils
2009
Nahmani, Johanne | Hodson, Mark E. | Devin, Simon | Vijver, Martina G.
It is well known that earthworms can accumulate metals. However, most accumulation studies focus on Cd-, Cu-, Pb- or Zn-amended soils, additionally few studies consider accumulation kinetics. Here we model the accumulation kinetics of 18 elements by Eisenia fetida, exposed to 8 metal-contaminated and 2 uncontaminated soils. Tissue metal concentrationwas determined after 3, 7, 14, 21, 28 and 42 days. Metal elimination rate was important in determining time to reach steady-state tissue metal concentration. Uptake flux to elimination rate ratios showed less variation and lower values for essential than for non-essential metals. In theory kinetic rate constants are dependent only on species and metal. Therefore it should be possible to predict steady-state tissue metal concentrations on the basis of very few measurements using the rate constants. However, our experiments show that it is difficult to extrapolate the accumulation kinetic constants derived using one soil to another.
Показать больше [+] Меньше [-]Risk assessment of potentially toxic element pollution in soils and rice (Oryza sativa) in a typical area of the Yangtze River Delta
2009
Hang, Xiaoshuai | Wang, Huoyan | Zhou, Jianmin | Ma, Chengling | Du, Changwen | Chen, Xiaoqin
Soil pollution with potentially toxic elements (PTEs) resulting from rapid industrial development has caused major concerns. Selected PTEs and their accumulation and distribution in soils and rice (Oryza sativa) collected from Changshu, east China, were analyzed to evaluate the potential health risk to the local population. The soils were primarily contaminated with Hg, followed by Cu, Cd, Pb, and Zn. The concentrations of Pb, Hg, and Cd of 46, 32, and 1 rice samples exceeded their national maximum allowable levels in foods, respectively. Spatial distributions of total Cr, Cu, Pb, Zn, and Cd in soils shared similar geographical trends. The risk assessment of PTEs through rice consumption suggests that the concentrations of Cu, Pb, and Cd in some rice samples exceed their reference oral dose for adults and children. In general, there was no target hazard quotient value of any individual element that was greater than 1, but hazard index values for adults and children were 1.726 and 1.523, respectively. Industrial development has led to increased risk from potentially toxic elements in soils and rice.
Показать больше [+] Меньше [-]Variation in arsenic, lead and zinc tolerance and accumulation in six populations of Pteris vittata L. from China
2009
Wu, F.Y. | Leung, H.M. | Wu, S.C. | Ye, Z.H. | Wong, M.H.
Arsenic, Pb and Zn tolerance and accumulation were investigated in six populations of Pteris vittata collected from As-contaminated and uncontaminated sites in southeast China compared with Pteris semipinnata (a non-As hyperaccumulator) in hydroponics and on As-contaminated soils. The results showed that both metallicolous and nonmetallicolous population of P. vittata possessed high-level As tolerance, and that the former exhibited higher As tolerance (but not Pb and Zn tolerance) than the latter. In hydroponic culture, nonmetallicolous population clearly showed significantly higher As concentrations in fronds than those in metallicolous populations. In pot trials, As concentrations in fronds of nonmetallicolous population ranged from 1060 to 1639 mg kg⁻¹, about 2.6- to 5.4-folds as those in metallicolous populations. It was concluded that As tolerance in P. vittata resulted from both constitutive and adaptive traits, Pb and Zn tolerances were constitutive properties, and that nonmetallicolous population possesses more effective As hyperaccumulation than metallicolous populations. Nonmetallicolous population of Pteris vittata L. possesses more effective arsenic hyperaccumulation than the metallicolous populations.
Показать больше [+] Меньше [-]Habitat type-based bioaccumulation and risk assessment of metal and As contamination in earthworms, beetles and woodlice
2009
Vermeulen, Frouke | Brink, Nico W. van den | D'Havé, Helga | Mubiana, Valentine K. | Blust, Ronny | Bervoets, Lieven | Coen, Wim De
The present study investigated the contribution of environmental factors to the accumulation of As, Cd, Cu, Pb and Zn in earthworms, beetles and woodlice, and framed within an exposure assessment of the European hedgehog. Soil and invertebrate samples were collected in three distinct habitat types. Results showed habitat-specific differences in soil and invertebrate metal concentrations and bioaccumulation factors when normalized to soil metal concentration. Further multiple regression analysis showed residual variability (habitat differences) in bioaccumulation that could not be fully explained by differences in soil metal contamination, pH or organic carbon (OC). Therefore, the study demonstrated that in bioaccumulation studies involving terrestrial invertebrates or in risk assessment of metals, it is not sufficient to differentiate habitat types on general soil characteristics such as pH and/or OC alone. Furthermore, simple generic soil risk assessments for Cd and Cu showed that risk characterization was more accurate when performed in a habitat-specific way. Our study provided essential insights into habitat-specific accumulation patterns with respect to factors influencing metal bioaccumulation, BAFs, and site-specific risk assessment.
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