Lead (Pb) and arsenic (As) bioaccessibility in various soils from south China

Cui, Yanshan; Chen, Xiaochen

doi:10.1007/s10661-010-1649-3

Cited by 17 publications

(13 citation statements)

References 47 publications

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“…17 The physiologically based extraction test (PBET) is a classic and mature in vitro method to assess As bioaccessibility in the gastric and small intestinal phases. 9,26 Therefore, in this study, the PBET method combined with the SHIME model was used to investigate (1) As metabolism of contaminated soils by human gut microbiota, (2) As bioaccessibility and its speciation in the small intestinal and colon phases, and (3) As distribution between extraction solution and the soil solid phase.…”

Section: ■ Introductionmentioning

confidence: 99%

In Vitro Method To Assess Soil Arsenic Metabolism by Human Gut Microbiota: Arsenic Speciation and Distribution

Yin

Zhang

Cai

et al. 2015

Environ. Sci. Technol.

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Arsenic (As) speciation and distribution are two important factors in assessing human health risk from As-contaminated soil. In this study, we used the combination of physiologically based extraction test (PBET) and Simulator of Human Intestinal Microbial Ecosystem (SHIME) to determine soil As metabolism by human gut microbiota. The results showed that the percentage of soil arsenate [As(V)] transformation reached 22.1−38.2%, while that of arsenite [As(III)] attained 66.5−92.0%; 30.1−56.4% of As(V) transformed was attached to the soil solid phase. In comparison to sequential extraction results, almost all amorphous Fe/Al-oxide-bound As was liberated in the colon phase. An X-ray absorption nearedge structure (XANES) showed that the As(III) percentage in the soil solid phase reached 16.6−26.9% and reached 73.4% (soil 1) in the colon phase. Additionally, plenty of As(III) and different extents of methylation were also observed in colon extraction solution. As bioaccessibility in the colon phase was 1.8−2.8 times that in the small intestinal phase. Our results indicated that human gut microbiota increased As bioaccessibility, and large amounts of As(III) were adsorbed onto the soil solid phase as a result of microbial reduction. Determining As speciation and distribution in extraction solution and soil solid phases will allow for an accurate assessment of the risk to human health upon soil As exposure. ■ INTRODUCTIONArsenic (As) is a common toxic contaminant that is extensively distributed in the environment. 1 Human exposure to As in soils is a major public concern and is associated with serious risks to human health because As species are known carcinogens. 2,3 In most cases, human exposure to soil As occurs via inhalation, inadvertent oral ingestion, and dermal contact. 4,5 Inadvertent oral ingestion has been considered an important exposure route for soil As, especially ingestion through outdoor hand-to-mouth activities by children. 6 The estimation of As bioaccessibility (gastric and small intestinal phases) in contaminated soils through in vitro methods has been used for human health risk assessment. On the basis of previous studies, 7−9 simple, fast, and inexpensive in vitro methods can effectively estimate in vivo relative As bioavailability. Generally, bioaccessibility is defined as the fraction of As that is soluble in the gastrointestinal environment of humans and available for absorption, whereas bioavailability is determined by the fraction of As that is absorbed into the systemic circulation. 7,8 Currently, As bioaccessibility in the gastric and small intestinal phases may underestimate its harm to human health. 10 Studies have clearly illustrated that gut microbiota significantly affect As metabolism by, for example, reduction, methylation, and thiolation. 11 As metabolism in contaminated soil by human gut microbiota can affect As bioaccessibility and speciation. 10,12 Therefore, As biotransformation must be considered an essential part of the risk assessment of oral soil As exposure using i...

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Section: ■ Introductionmentioning

confidence: 99%

In Vitro Method To Assess Soil Arsenic Metabolism by Human Gut Microbiota: Arsenic Speciation and Distribution

Yin

Zhang

Cai

et al. 2015

Environ. Sci. Technol.

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“…In addition, organic constituents in the gastric phase can influence the solubility of As and Fe . Nevertheless, soil properties (i.e., total As concentration, particle size, and mineral phases) may also affect the As bioaccessibility, as reported in previous studies (Cui and Chen, 2011;Juhasz et al, 2009;Smith et al, 2014;Yang et al, 2003;Yin et al, 2015a). Presumably, the differences in As bioaccessibility are a result of synergistic effects between the in vitro parameters and soil properties.…”

Section: Arsenic Speciation Analysismentioning

confidence: 69%

Variability of arsenic bioaccessibility and metabolism in soils by human gut microbiota using different in vitro methods combined with SHIME

Yin

Zhang

et al. 2016

Science of The Total Environment

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• Five in vitro gastrointestinal methods combined with SHIME (colon phase) were used.• As bioaccessibility varied in the colon phase among these methods.• Plenty of As(III) and methylated arsenicals by microbial transformation were observed.• As bioaccessibility in PBET/SBRC-SHIME colon phase were closer to in vivo results for NIST 2710a. Arsenic (As) speciation analysis is essential when evaluating the risks upon oral exposure to As-contaminated soils. In this study, we first investigated the variability in the As bioaccessibility and speciation using a combination of five common in vitro methods (SBRC, PBET, DIN, UBM and IVG) (gastric and small intestinal phases) and the SHIME model (colon phase). Our results indicate that the As bioaccessibility varies in the colon phase. An increase in the As bioaccessibility for SBRC and PBET, and a decrease for UBM and IVG were observed in the colon phase. In addition, we found different extents of methylation and large amounts of arsenite [As(III)] due to microbial reduction in the colon digests. The UBM-SHIME method displayed a higher methylation percentage of 13.5-82.1%, but a lower methylation percentage of 0.2-21.8% was observed in the SBRC-SHIME method. Besides, The MMA V levels in the colon digests were positively correlated with those of As(III) and DMA V , so DMA V can be considered an indicator to evaluate the As metabolic speed of in vitro cultured human gut microbiota. Based on the standard reference soil of NIST 2710a, the As bioaccessibility in the colon phase of PBET-SHIME and SBRC-SHIME were the closest to the in vivo results. Combining in vitro methods and SHIME will remarkably affect the accurate assessment of potential risks to human health associated with oral exposure to soil As.

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“…Any increased concentration of such elements like lead (Pb) in soil presents a health threat to most creatures and humans [1][2][3]. Extraction of these elements is also important for several industrial applications such as ammunition, burial vault liners, ceramic glazes, leaded class and crystal and water lines and pipes [4].…”

Section: Introductionmentioning

confidence: 99%

“…Traditionally, Pb contents in soils have been determined in a laboratory where prepared soil samples are subjected to expensive and time consuming analysis [2,5,6]. Regarding access to high resolution and accurate spectral data (which are obtained via field spectrometry or space-born hyper spectral imaging), spectroscopy is an appropriate alternative to the afore-mentioned traditional chemical analysis [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

A Robust Fuzzy Neural Network Model for Soil Lead Estimation from Spectral Features

2015

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Soil lead content is an important parameter in environmental and industrial applications. Chemical analysis, the most commonly method for studying soil samples, are costly, however application of soil spectroscopy presents a more viable alternative. The first step in the method is usually to extract some appropriate spectral features and then regression models are applied to these extracted features. The aim of this paper was to design an accurate and robust regression technique to estimate soil lead contents from laboratory observed spectra. Three appropriate spectral features were selected according to information from other research as well as the spectrum interpretation of field collected soil samples containing lead. These features were then applied to common Multiple Linear Regression (MLR), Partial Least Square Regression (PLSR) and Neural Network (NN) regression models. Results showed that although NN had adequate accuracy, it produced unstable results (i.e., variation of response in different runs). This problem was addressed with application of a Fuzzy Neural Network (FNN) with a least square training strategy. In addition to the stabilized and unique response, the capability of the proposed FNN was proved in terms of regression accuracy where a Ratio of Performance to Deviation (RPD) of 8.76 was achieved for test samples.

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Lead (Pb) and arsenic (As) bioaccessibility in various soils from south China

Cited by 17 publications

References 47 publications

In Vitro Method To Assess Soil Arsenic Metabolism by Human Gut Microbiota: Arsenic Speciation and Distribution

In Vitro Method To Assess Soil Arsenic Metabolism by Human Gut Microbiota: Arsenic Speciation and Distribution

Variability of arsenic bioaccessibility and metabolism in soils by human gut microbiota using different in vitro methods combined with SHIME

A Robust Fuzzy Neural Network Model for Soil Lead Estimation from Spectral Features

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