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ABSTRACT: The aim of the present work is to investigate the distribution of arsenic (As) in sewage irrigation area, to deduce the migration
and transformation mechanism of As in soil and groundwater, and to infer the source of As in soil and groundwater. This study
is carried out in a sewage irrigation area of the Pearl River Delta, China. Surface water samples, soil samples, and groundwater
samples from sewage irrigation area were analyzed for As and other elements. As contents in water samples were analyzed by
hydride generation-atomic fluorescence spectroscopy, and As fractionation in soil samples was extracted using a seven-step
sequential extraction method according to a seven fraction scheme: water soluble, ion exchangeable, bound to carbonate, weakly
bound to organic matter, associated with oxides of iron (Fe) and manganese (Mn), strongly bound to organic matter, and the
residual fraction. Waste water has content of As up to 16.8 μg/L in the study area. Soil has enriched As due to the irrigation
of soil with waste water, and the total content of As in soil is about 0.7 times higher than the background value. Sequential
extraction method reveals that the mean content of residual fraction in soil is more than 70%, releasable fraction (weakly
organic fraction, Fe-Mn oxide fraction, and carbonate fraction) is about 20%–30%, whereas strongly organic and mobile fractions
(water soluble and ion exchangeable) are within 0.2%. In the soil profile, the contents of water soluble, ion exchangeable,
and carbonate fraction decrease with the depth, whereas the contents of other fractions are irregular with the depth. Using
correlation analysis, it is concluded that water soluble fraction is easy to change into ion exchangeable and carbonate fraction,
ion exchangeable fraction is easy to change into carbonate and Fe-Mn oxide fraction, and carbonate fraction is easy to change
into weakly organic and Fe-Mn oxide fraction in the soil of study area. Organic matter and (hydr)oxides of Fe and aluminium
(Al) in soil play an important role in controlling the distribution and mobility of As in soil. As concentrations in groundwater
range from 2.8 to 21.0 μg/L, and it is inferred that As from waste water and the release of high As sediment (soil and aquifer
medium) are the main sources for high As groundwater in study area. Using cluster analysis, it is concluded that reducing
groundwater with slightly alkaline is beneficial to enrichment of As in groundwater, and hydroxides of Fe, Mn, and Al also
play a key role for the enrichment of As in groundwater of the study area.
Key Wordsarsenic–sewage irrigation area–soil–groundwater–fraction
Journal of Earth Science 04/2012; 22(3):396-410. · 0.31 Impact Factor
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Haiwei Cui,
Jichao Sun,
Jincui Wang,
Yuxi Zhang,
Xi Chen,
Ying Zhang,
Yuanjing Zhang,
Xiaoping Xiang,
Jihong Jing,
Guanxing Huang, Jingtao Liu
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ABSTRACT: Following the introduction of characteristic of wastewater and correlated project in the Alpine Region, the problems were pointed out which should be noticed in wastewater treatment process selection in this specific area. Some suggestions about key design parameters were proposed, and the Two-stage Bio-contact Oxidation Technology was been selected and applied in wastewater treatment plant in north suburb of Dongsheng District, Erdos City. Through project application, it was indicated that when average value of COD, BOD5 and SS was 483.2 mg/L, 244.4 mg/L and 258.4 mg/L respectively during 10 days at about 12°C in influent wastewater, average value in effluent water reached up to 57.1 mg/L, 23.8 mg/L and 26.5 mg/L and removal rate of each contaminant was up to 88.2%, 90.3% and 89.7% respectively. It gained preferable results and this successful project also provided references for other similar wastewater treatment plant for future.
Intelligent Computation Technology and Automation (ICICTA), 2011 International Conference on; 04/2011
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ABSTRACT: The Distribution of shallow groundwater containing beryllium were summarized and the major factors influencing beryllium enrichment were discussed in this paper, based on chemical data of Be, aluminum and pH from more than 900 groundwater samples in the Pearl River Delta. The results show that Be concentration ranges from less than 0.02μg·L<sup>-1</sup> to 40.3μg·L<sup>-1</sup>, with the majority less than 0.05μg·L<sup>-1</sup> and the mean Be content of 0.66μg·L<sup>-1</sup>. The samples of Be content exceeding the upper limit for drinking water in China were scatteredly found in Guangzhou, Shenzhen, Dongguan, Foshan and Huizhou, with the over proof rate of 2.24%. The distribution of Be contamination in groundwater is characterized by local punctate type. The pH and Al are the major factors influencing distribution of beryllium in groundwater. Acidic and high Al content in groundwater and soil provide favorable conditions for migration of Be. Rock weathering and natural soil formation is one of the origins of Be in groundwater, and pollution caused by human activities is the other important source of Be in groundwater, especially in the severely contaminated sites.
Digital Manufacturing and Automation (ICDMA), 2010 International Conference on; 01/2011
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ABSTRACT: The contents and characteristics of ten heavy metals in surface sediments from Yangzonghai Lake in Yunnan, China were analyzed. Ecological risk index presented by Håkanson to assess the potential ecological risk of Yangzonghai Lake was utilized. The results showed that the average concentrations of titanium(Ti), manganese(Mn), zinc(Zn), vanadium(V), chromium(Cr), copper(Cu), nickel(Ni), cobalt(Co), lead(Pb) and arsenic(As) in surface sediments of Yangzonghai Lake were up to 9413.1, 617.9, 149.2, 189.6, 145.8, 97.6, 55.1, 27.4, 40.3 and 31.4mg/kg, respectively, which are higher than their natural background values. Pearson's correlation analysis indicated that Zn, Cr, Pb and As were highly correlated, and the similar distributions in sediment indicated that they might originate from activities. Ti, Mn, V, Cu, Ni, and Co were also well correlated, and the distributions indicated that they were mainly from natural factors. The evaluation of pollution index revealed a clear accumulation of the 10 heavy metals, all reaching the level of moderate pollution. As, Cu and Cr were the most important environmental contaminants in Yangzonghai Lake. As a whole, heavy metals reached the level of low ecological risks, and in some parts, they reached the moderate level. Heavy metals in Yangzonghai Lake in the descending order of their ecological risks were As, Cu, Co, Ni, Pb, Cr, V, Zn, Mn and Ti. As was more prominent than other heavy metals in terms of the ecological risk and thus the most important factor of potential ecological risk in surface sediment of Yangzonghai Lake.
Digital Manufacturing and Automation (ICDMA), 2010 International Conference on; 01/2011
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ABSTRACT: The research reveals the mobility and distribution of heavy metals (Cd, Cu, Zn, Mn, Ni, and Cr) in soil of sewage irrigation area in Pearl River Delta. Samples were collected from topsoil (0-10cm) and subsoil (30-40cm), and the total concentration and available concentration of heavy metals were extracted by HNO<sub>3</sub>-HF-HClO<sub>4</sub> and DTPA respectively. The mean total concentrations for all of the heavy metals in topsoil are higher than that in subsoil in study area. Cd has the best mobility in soil of study area due to soil has lower retention for Cd than for other metals, while Ni has the poorest mobility in soil of study area. The total concentrations of Zn, Cu and Cd decrease with the depth of soil profile, while the total concentrations of Cr and Ni have little change with the depth of soil profile, only the total concentration of Mn has a little decrease at first and then increased rapidly with the depth of soil profile.
Digital Manufacturing and Automation (ICDMA), 2010 International Conference on; 01/2011
