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Assessing arsenic intake from groundwater and rice by residents in Prey Veng province, Cambodia
2014
Phan, Kongkea | Phan, Samrach | Heng, Savoeun | Huoy, Laingshun | Kim, Kyoung-Woong
We investigated total daily intake of As by residents in Prey Veng province in the Mekong River basin of Cambodia. Groundwater (n = 11), rice (n = 11) and fingernail (n = 23) samples were randomly collected from the households and analyzed for total As by inductively coupled plasma mass spectrometry. Calculation indicated that daily dose of inorganic As was greater than the lower limits on the benchmark dose for a 0.5% increased incidence of lung cancer (BMDL0.5 equals to 3.0 μg d−1 kg−1body wt.). Moreover, positive correlation between As in fingernail and daily dose of As from groundwater and rice and total daily dose of As were found. These results suggest that the Prey Veng residents are exposed to As in groundwater. As in rice is an additional source which is attributable to high As accumulation in human bodies in the Mekong River basin of Cambodia.
显示更多 [+] 显示较少 [-]Arsenic enhanced plant growth and altered rhizosphere characteristics of hyperaccumulator Pteris vittata
2014
Xu, Jia−Yi | Li, Hong−Bo | Liang, Shuang | Luo, Jun | Ma, Lena Q.
We investigated the effects of arsenic species on As accumulation, plant growth and rhizospheric changes in As−hyperaccumulator Pteris vittata (PV). PV was grown for 60−d in a soil spiked with 200 mg kg−1 arsenate (AsV−soil) or arsenite (AsIII−soil). Diffusive gradients in thin−films technique (DGT) were used to monitor As uptake by PV. Interestingly AsIII−soil produced the highest PV biomass at 8.6 g plant−1, 27% and 46% greater than AsV−soil and the control. Biomass increase was associated with As−induced P uptake by PV. Although AsIII was oxidized to AsV during the experiment, As species impacted As accumulation by PV, with 17.5% more As in AsIII−soil than AsV−soil (36 vs. 31 mg plant−1). As concentration in PV roots was 30% higher in AsV−soil whereas As concentration in PV fronds was 7.9% greater in AsIII−soil, suggesting more rapid translocation of AsIII than AsV. These findings were important to understand the mechanisms of As uptake, accumulation and translocation by PV.
显示更多 [+] 显示较少 [-]Association between risk of birth defects occurring level and arsenic concentrations in soils of Lvliang, Shanxi province of China
2014
Wu, Jilei | Zhang, Chaosheng | Pei, Lijun | Chen, Gong | Zheng, Xiaoying
The risk of birth defects is generally accredited with genetic factors, environmental causes, but the contribution of environmental factors to birth defects is still inconclusive. With the hypothesis of associations of geochemical features distribution and birth defects risk, we collected birth records and measured the chemical components in soil samples from a high prevalence area of birth defects in Shanxi province, China. The relative risk levels among villages were estimated with conditional spatial autoregressive model and the relationships between the risk levels of the villages and the 15 types of chemical elements concentration in the cropland and woodland soils were explored. The results revealed that the arsenic levels in cropland soil showed a significant association with birth defects occurring risk in this area, which is consistent with existing evidences of arsenic as a teratogen and warrants further investigation on arsenic exposure routine to birth defect occurring risk.
显示更多 [+] 显示较少 [-]Elemental bioimaging of tissue level trace metal distributions in rice seeds (Oryza sativa L.) from a mining area in China
2014
Basnet, Priyanka | Amarasiriwardena, Dulasiri | Wu, Fengchang | Fu, Zhiyou | Zhang, Tao
Rice is a staple food and major source of nutrients, but it also bioaccumulates toxic elements. In this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to determine tissue-level trace metal spatial distribution in rice (Oryza sativa) seeds from the active Xikuangshan Sb mine area in China. Whole grain quantified elemental bioimages showed the highest concentration of Zn (1755 mg/kg) in the embryo andmicro zones of elevated Sb, As, Pb, Cd as high as 280, 57, 31 and 830 mg/kg, respectively on the husk/bran/endosperm tissues. Bioimages suggest that both Sb and Cd may be competing with Zn for binding sites. Both Sb(III) and Sb(V) species were detected in seeds from upstream and downstream fields indicating the presence of toxic Sb(III). Brown rice is a good source of Zn, but white rice is a safer option if rice is grown in a polluted area.
显示更多 [+] 显示较少 [-]Arsenic speciation in total contents and bioaccessible fractions in atmospheric particles related to human intakes
2014
Huang, Minjuan | Chen, Xunwen | Zhao, Yinge | Yu Chan, Chuen | Wang, Wei | Wang, Xuemei | Wong, Ming Hung
Speciation of inorganic trivalent arsenicals (iAsIII), inorganic pentavalent arsenicals (iAsV), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in total arsenic (As) content and its bioaccessible fractions contained in road dust, household air-conditioning (AC) filter dust and PM2.5 was investigated. Inorganic As, especially iAsV, was observed as the dominant species. Physiologically based extraction test (PBET), an in-vitro gastrointestinal method, was used to estimate the oral As bioaccessibility in coarse particles and the species present in the oral bioaccessible fraction. A composite lung simulating serum was used to mimic the pulmonary condition to extract the respiratory bioaccessible As and its species in PM2.5. Reduction of iAsV to iAsIII occurred in both in-vitro gastrointestinal and lung simulating extraction models. The inorganic As species was the exclusive species for absorption through ingestion and inhalation of atmospheric particles, which was an important exposure route to inorganic As, in addition to drinking water and food consumption.
显示更多 [+] 显示较少 [-]Assessing the influence of compost and biochar amendments on the mobility and toxicity of metals and arsenic in a naturally contaminated mine soil
2014
Beesley, Luke | Inneh, Onyeka S. | Norton, Gareth J. | Moreno-Jimenez, Eduardo | Pardo, Tania | Clemente, Rafael | Dawson, Julian J.C.
Amending contaminated soils with organic wastes can influence trace element mobility and toxicity. Soluble concentrations of metals and arsenic were measured in pore water and aqueous soil extracts following the amendment of a heavily contaminated mine soil with compost and biochar (10% v:v) in a pot experiment. Speciation modelling and toxicity assays (Vibrio fischeri luminescence inhibition and Lolium perenne germination) were performed to discriminate mechanisms controlling metal mobility and assess toxicity risk thereafter. Biochar reduced free metal concentrations furthest but dissolved organic carbon primarily controlled metal mobility after compost amendment. Individually, both amendments induced considerable solubilisation of arsenic to pore water (>2500 μg l−1) related to pH and soluble phosphate but combining amendments most effectively reduced toxicity due to simultaneous reductions in extractable metals and increases in soluble nutrients (P). Thus the measure–monitor-model approach taken determined that combining the amendments was most effective at mitigating attendant toxicity risk.
显示更多 [+] 显示较少 [-]Maternal transfer and embryonic assimilation of trace elements in freshwater turtles after remediation of a coal fly-ash spill
2014
Van Dyke, James U. | Steen, David A. | Jackson, Brian P. | Hopkins, William A.
Oviparous vertebrates maternally transfer elements to their offspring during egg production. Maternal transfer occurs because elements mimic, or are incorporated into, nutrients allocated to eggs, but likely differs among species depending on the quantities of specific nutrients allocated to eggs. Developing embryos are often assumed to assimilate all of the elements allocated to eggs, but this assumption has rarely been tested. We tested the hypothesis that maternal transfer and embryonic assimilation of trace elements differed between two species of freshwater turtles exposed to a recently-remediated coal fly-ash spill. Sternotherus odoratus transferred As, Se, and Zn, while Trachemys scripta transferred As, Hg, Se, Sr, and Zn. Logarithmic non-linear relationships between hatchling and egg concentrations indicated that turtles partially assimilated elements present in eggs. In systems contaminated with multiple trace elements, our data show that maternal transfer and embryonic assimilation are element- and species-specific, and may be inconsistent even among closely-related species.
显示更多 [+] 显示较少 [-]Effects of arsenate, chromate, and sulfate on arsenic and chromium uptake and translocation by arsenic hyperaccumulator Pteris vittata L
2014
de Oliveira, Letúzia Maria | Ma, Lena Q. | Santos, Jorge A.G. | Guilherme, Luiz R.G. | Lessl, Jason T.
We investigated effects of arsenate (AsV), chromate (CrVI) and sulfate on As and Cr uptake and translocation by arsenic hyperaccumulator Pteris vittata (PV), which was exposed to AsV, CrVI and sulfate at 0, 0.05, 0.25 or 1.25 mM for 2-wk in hydroponic system. PV was effective in accumulating large amounts of As (4598 and 1160 mg/kg in the fronds and roots at 0.05 mM AsV) and Cr (234 and 12,630 mg/kg in the fronds and roots at 0.05 mM CrVI). However, when co-present, AsV and CrVI acted as inhibitors, negatively impacting their accumulation in PV. Arsenic accumulation in the fronds was reduced by 92% and Cr by 26%, indicating reduced As and Cr translocation. However, addition of sulfate increased uptake and translocation of As by 26–28% and Cr by 1.63 fold. This experiment demonstrated that As and Cr inhibited each other in uptake and translocation by PV but sulfate enhanced As and Cr uptake and translocation by PV.
显示更多 [+] 显示较少 [-]Urinary excretion of arsenic following rice consumption
2014
Meharg, A.A. | Williams, P.N. | Deacon, C.M. | Norton, G.J. | Hossain, M. | Louhing, D. | Marwa, E. | Lawgalwi, Y. | Taggart, M. | Cascio, C. | Haris, P.
Patterns of arsenic excretion were followed in a cohort (n = 6) eating a defined rice diet, 300 g per day d.wt. where arsenic speciation was characterized in cooked rice, following a period of abstinence from rice, and other high arsenic containing foods. A control group who did not consume rice were also monitored. The rice consumed in the study contained inorganic arsenic and dimethylarsinic acid (DMA) at a ratio of 1:1, yet the urine speciation was dominated by DMA (90%). At steady state (rice consumption/urinary excretion) ∼40% of rice derived arsenic was excreted via urine. By monitoring of each urine pass throughout the day it was observed that there was considerable variation (up to 13-fold) for an individual's total arsenic urine content, and that there was a time dependent variation in urinary total arsenic content. This calls into question the robustness of routinely used first pass/spot check urine sampling for arsenic analysis.
显示更多 [+] 显示较少 [-]Antimony uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata
2014
Tisarum, Rujira | Lessl, Jason T. | Dong, Xiaoling | de Oliveira, Letuzia M. | Rathinasabapathi, Bala | Ma, Lena Q.
Even though antimony (Sb) and arsenic (As) are chemical analogs, differences exist on how they are taken up and translocated in plants. We investigated 1) Sb uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata after 1 d exposure to 1.6 or 8 mg/L antimonite (SbIII) or antimonate (SbV), 2) Sb uptake by PV accessions from Florida, China, and Brazil after 7 d exposure to 8 mg/L SbIII, and 3) Sb uptake and oxidation by excised PV fronds after 1 d exposure to 8 mg/L SbIII or SbV. After 1 d exposure, P. vittata took 23–32 times more SbIII than SbV, with all Sb being accumulated in the roots with the highest at 4,192 mg/kg. When exposed to 8 mg/L SbV, 98% of Sb existed as SbV in the roots. In comparison, when exposed to 8 mg/L SbIII, 81% of the total Sb remained as SbIII and 26% of the total Sb was effluxed out into the media. The three PV accessions had a similar ability to accumulate Sb at 12,000 mg/kg in the roots, with >99% of total Sb in the roots. Excised PV fronds translocated SbV more efficiently from the petioles to pinnae than SbIII and were unable to oxidize SbIII. Overall, P. vittata displayed efficient root uptake and efflux of SbIII with limited ability to translocate and transform in the roots.
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