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النتائج 1 - 10 من 45
Identification of Chinese cabbage genotypes with low cadmium accumulation for food safety
2009
Liu, Weitao | Zhou, Qixing | Sun, Yuebing | Liu, Rui
The pot-culture experiment and field studies were conducted to screen out and identify cadmium (Cd) excluders from 40 Chinese cabbage genotypes for food safety. The results of the pot-culture experiment indicated that the shoot Cd concentrations under three treatments (1.0, 2.5 and 5.0 mg Cd kg⁻¹ Soil) varied significantly (p < 0.05), with average values of 0.70, 3.07 and 5.83 mg kg⁻¹, respectively. The Cd concentrations in 12 cabbage genotypes were lower than 0.50 mg kg⁻¹. The enrichment factors (EFs) and translocation factors (TFs) in 8 cabbage genotypes were lower than 1.0. The field studies further identified Lvxing 70 as a Cd-excluder genotype (CEG), which is suitable to be planted in low Cd-contaminated soils (Cd concentration should be lower than 1.25 mg kg⁻¹) for food safety. Lvxing 70 was identified as a Cd-excluder genotype (CEG) and suitable to be cultivated in low Cd-contaminated soils for food safety.
اظهر المزيد [+] اقل [-]Chemical and ecotoxicological analyses of sediments and elutriates of contaminated rivers due to e-waste recycling activities using a diverse battery of bioassays
2009
Wang, F. | Leung, A.O.W. | Wu, S.C. | Yang, M.S. | Wong, M.H.
A multi-trophic, multi-exposure phase assessment approach was applied to characterize the toxicity of sediments collected from two rivers in Guiyu, China, an e-waste recycling centre. Elutriate toxicity tests (bacterium Vibrio fischeri and microalga Selenastrum capricornutum) and whole sediment toxicity test (crustacean Heterocypris incongruens) showed that most sediments exhibited acute toxicity, due to elevated heavy metals and PAHs levels, and low pH caused by uncontrolled acid discharge. The survival rates of crustaceans were negatively (p < 0.05) correlated with total PAHs in sediments (411-1755 mg kg⁻¹); EC50s of V. fischeri on the elutriates were significantly correlated with elutriate pH (p < 0.01). Significant (p < 0.05) correlations between the induction of hepatic metallothionein in tilapia (Oreochromis mossambicus) and metal concentrations (Cu, Zn, Pb) in sediments were also observed, when fish were fed with diets containing sediment. The results showed that uncontrolled e-waste recycling activities may bring adverse effects to local aquatic ecosystem. Toxicity tests using different trophic organisms provided important information, supplementing chemical analyses.
اظهر المزيد [+] اقل [-]Organochlorine pesticide residuals in chickens and eggs at a poultry farm in Beijing, China
2009
Tao, S. | Liu, W.X. | Li, X.Q. | Zhou, D.X. | Li, Xunjing | Yang, Y.F. | Yue, D.P. | Coveney, R.M.
Chicken organs, animal feed, droppings, and ambient air were sampled at a farm in Beijing to determine the concentrations of hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites (DDTs). Mean fresh weight concentrations of HCHs and DDTs were 0.122 ± 0.061 ng/g and 0.051 ± 0.038 ng/g in the muscles. These values are 1-2 orders of magnitude lower than those reported in China in 1980. Contaminated feed was the main source of HCHs and DDTs. Only 12.8% of HCH and 3.3% of DDT of the amount consumed were excreted. Accumulated quantities of HCHs and DDTs increased during growth. However, concentrations of HCHs and DDTs did not increase because of dilution from rapid growth. Based on the observed residual levels in mature chicken and the average diet of residents of China, the contributions from chicken and egg consumption to per capita daily intake of HCHs and DDTs were 487% and 88% of those of fish consumption.
اظهر المزيد [+] اقل [-]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.
اظهر المزيد [+] اقل [-]Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils
2009
Li, Yong-Tao | Becquer, Thierry | Dai, Jun | Quantin, Cécile | Benedetti, Marc F.
The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils. First evidence of the real free metal ion concentrations in acid mine drainage context in tropical systems.
اظهر المزيد [+] اقل [-]Detection of phosphorus species in sediments of artificial landscape lakes in China by fractionation and phosphorus-31 nuclear magnetic resonance spectroscopy
2009
Liu, Jinyong | Wang, Hui | Yang, Haijun | Ma, Yanjun | Cai, Ouchen
Phosphorus (P) pollution in the sediments of seven artificial landscape lakes was studied via fractionation and phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy. The lake sediments accumulated significant amounts of P from supplementation with reclaimed water and from runoff from the golf course lawns. The differences in total sediment P among lakes were correlated to the varied pollution extent from the lawns. One striking feature of the artificial lake sediments was the insufficiency of NaOH-extracted Al, which plays an important role in avoiding internal P release during anoxia. Another characteristic was the dominance of orthophosphate in the NaOH-EDTA extractants of the sediments, due to the heavy external P pollution. Phytate, considered prevalent in many soils and lake sediments, as well as polyphosphates and phosphonates which have appeared in some natural lake sediments, was not detected. The rank order of present biogenic P species was monoester-P > DNA-P > pyrophosphate > lipid-P. Mineral fixation and biological conversion of phosphorus were investigated in artificial lake sediments in China.
اظهر المزيد [+] اقل [-]Spatial distribution and vertical profile of polybrominated diphenyl ethers, tetrabromobisphenol A, and decabromodiphenylethane in river sediment from an industrialized region of South China
2009
Zhang, Xiu-Lan | Luo, Xiao-Jun | Chen, She-Jun | Wu, Jiang-Ping | Mai, Bi-Xian
Polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), and decabromodiphenylethane (DBDPE) were detected in fifteen surface sediments and two sediment cores collected from a river in one heavily industrialized region of South China. TBBPA and DBDPE were detected with concentrations ranging from 3.8 to 230 ng/g dw and from 23 to 430 ng/g dw, respectively. Σtri-hepta-BDEs and Σnona-deca-BDEs ranged from 0.7 to 7.6 ng/g dw and from 30 to 5700 ng/g dw, respectively. Σtri-hepta-BDEs showed an increasing trend whereas for Σnona-deca-BDE two sediment cores revealed a decreasing trend in more recent sediment layers which may attributed to the introduction of DBDPE. The rapid increasing trend for TBBPA and DBDPE in recent sediment layers well reflected the rising demand of these two compounds in study area. Ubiquitous and historical contamination by PBDE, TBBPA, and DBDPE in river sediments from an industrialized region of South China
اظهر المزيد [+] اقل [-]Assessment of atmospheric sulfur with the epilithic moss Haplocladium microphyllum: Evidences from tissue sulfur and δ34S analysis
2009
Liu, Xue-Yan | Xiao, Hua-Yuan | Liu, Cong-Qiang | Xiao, Hong-Wei | Wang, Yan-Li
The application of geochemical signals in mosses is more and more popular to investigate the deposition of atmospheric pollutants, but it is unclear whether records of atmospheric sulfur in mosses differ between their diverse habitats. This study aimed to investigate the influence of growing condition on tissue sulfur and δ³⁴S of Haplocladium microphyllum. Epilithic and terricolous mosses in open fields, mosses under different canopy conditions were considered. We found that tissue sulfur and δ³⁴S of mosses under different habitats were not consistent and could not be compared for atmospheric sulfur research with each other even collected at the same site, moss sulfur and δ³⁴S records would be distorted by subsoil and upper canopies in different degrees, which possibly mislead the interpretation of atmospheric sulfur level and sources. Consequently, mosses on open rocks can be used reliably to assess atmospheric-derived sulfur in view of their identical sulfur and δ³⁴S evidences. Mosses on open rocky surfaces are reliable bioindicators of atmospheric sulfur deposition.
اظهر المزيد [+] اقل [-]Levels and distribution of polybrominated diphenyl ethers (PBDEs) in the freshwater environment surrounding a PBDE manufacturing plant in China
2009
Xu, Jie | Gao, Zishen | Xian, Qiming | Yu, Hongxia | Feng, Jianfang
Polybrominated diphenyl ethers (PBDEs) were determined in muscle, liver and eggs of freshwater fishes and surface sediments from the Nongkang River in Jinhu, Jiangsu Province, China. The present study is the first to report PBDE concentrations in the freshwater environment surrounding a PBDE manufacturing plant in China. The concentrations of 13 PBDE congeners in muscle, liver and eggs of freshwater fishes ranged from <LOD to 130, <LOD to 252 and <LOD to 33.3 ng/g lipid wt, respectively, while the concentrations of 13 PBDE congeners in surface sediments from sewage outfall, upstream and downstream of the river were 52, 9.2, 7.1 ng/g organic carbon wt, respectively. Contamination by PBDEs in this area was not serious when compared with other regions of the world. A relatively high proportion of BDE-183 was found, consistent with the octa-BDE technical mixtures from the manufacturing plant by the side of the river. The first study to report concentrations of PBDEs in the freshwater environment surrounding a PBDE manufacturing plant in China.
اظهر المزيد [+] اقل [-]Fate of polybrominated diphenyl ethers in the environment of the Pearl River Estuary, South China
2009
Guan, Yu-Feng | Sojinu, O.S Samuel | Li, Shao-Meng | Zeng, E. Y. (Eddy Y)
Ninety-six riverine runoff samples collected at eight major outlets in the Pearl River Delta (PRD), South China, during 2005-2006 were analyzed for 17 brominated diphenyl ether (BDE) congeners (defined as Σ17PBDE). Fourteen and 15 congeners were detected, respectively, in the dissolved and particulate phases. These data were further used to elucidate the partitioning behavior of BDE congeners in riverine runoff. Several related fate processes, i.e. air-water exchange, dry and wet deposition, degradation, and sedimentation, within the Pearl River Estuary (PRE), were examined to estimate the inputs of Σ10PBDE (sum of the target BDE congeners, BDE-28, -47, -66, -85, -99, -100, -138, -153, -154, and -183) and BDE-209 from the PRD to the coastal ocean based on mass balance considerations. The results showed that annual outflows of Σ10PBDE and BDE-209 were estimated at 126 and 940 kg/year, respectively from the PRE to coastal ocean. Besides sedimentation and degradation, the majority of Σ10PBDE and BDE-209 discharged into the PRE via riverine runoff was transported to the coastal ocean. Fate of polybrominated diphenyl ethers in the environment the Pearl River Estuary, South China.
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