Inorganic arsenic in Chinese food and its cancer risk

Li, Gang; Sun, Guoxin; Williams, Paul N.; Nunes, Luís Saboga; Zhu, Yan

doi:10.1016/j.envint.2011.05.007

Cited by 355 publications

(179 citation statements)

References 39 publications

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“…Table S10); ED is the exposure duration (y) from the questionnaire; AT is the average life expectancy (25 550 day); 23 and BW is the body weight (male: 61.0 kg; female: 53.2 kg). 24 Toxic and cancer risk assessment was estimated using eqs 2 and 3, respectively:…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Arsenic Levels and Speciation from Ingestion Exposures to Biomarkers in Shanxi, China: Implications for Human Health

Cui

Shi

Jiang

et al. 2013

Environ. Sci. Technol.

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Chronic exposure to arsenic (As) threatens human health. To systematically understand the health risks induced by As ingestion, we explored water and diet contributions to As exposure, and compared As in biomarkers and the arsenicosis in a geogenic As area in China. In this study, high percentages of water (77% of n = 131 total samples), vegetables (92%, n = 120), cereals (32%, n = 25), urine (70%, n = 99), nails (76%, n = 176), and hair (62%, n = 61) contained As higher than the acceptable levels. Dietary As contributed 92% of the average daily dose (ADD) when the water As concentration was less than 10 μg/L, for which 5 out of 30 examined participants were diagnosed with arsenicosis symptoms. The distinct positive correlation between ADD and As concentrations in urine, nails, and hair suggests different applicability for these biomarkers. Methylated As as the predominant urinary As species confirms that the ingested inorganic As is methylated and is excreted through urine. In situ microdistribution and speciation analysis indicates that As is mainly associated with sulfur in nails and hair. Nails, rather than hair and urine, could be used as a proper biomarker for arsenicosis. High ADD from the environment and low excretion could result in As toxicity to humans. ■ INTRODUCTIONArsenic (As) poses a severe threat to human health through exposure pathways mainly including water and diet. 1,2 Drinking water with elevated As levels is the primary source of As ingestion. 1,3 Moreover, As-laden groundwater, if used for irrigation, can lead to appreciable amounts of As accumulation in vegetables and cereals. 4−6 Extensive research demonstrates that rice and rice products could be another As source. 7,8 However, not much attention has been paid to other cereals like wheat, which are important staple foods worldwide, that could lead to significant As ingestion. 9 The intake of As results in its detection in noninvasive human biomarkers such as urine, nails, and hair. 10−12 Urine has frequently been used as a biomarker for short-term exposure because most As metabolites are excreted within 3−4 days through urine. 12,13 Nails and hair indicate long-term exposure for 2−12 months, 10 as As can be accumulated in these structures rich in keratin. 14 Thus, the association of As levels in biomarkers and groundwater has been recently studied to evaluate its health risks. 11,15 The speciation of As in biomarkers is crucial to understand the transformation, metabolism, and toxicity of ingested As. 12,16 As species in hair and nails are traditionally determined by chemical extraction, where inorganic and methylated As are detected. 14,17 No As−S species have been reported using indirect chemical extraction methods, even though As readily bonds to sulphydryl groups. 14 In contrast, As−S species have been detected in nail and hair samples using in situ X-ray absorption near-edge structure (XANES) spectroscopy. 15 Unfortunately, methylated As species are not distinguished from the As−S form in nails, 18 which deserves further...

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Arsenic Levels and Speciation from Ingestion Exposures to Biomarkers in Shanxi, China: Implications for Human Health

Cui

Shi

Jiang

et al. 2013

Environ. Sci. Technol.

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“…Arsenic is a ubiquitous environmental contaminant and a notorious carcinogen posing both acute and chronic adverse effects on human health mainly through ingestion of contaminated water and rice (Zhu et al 2008a;Rahman et al 2009;Li et al 2011). Large areas of farmland have been contaminated by arsenic (As) due to the irrigation with As-enriched groundwater or the contamination by mining and other activities (Zhu et al 2008b;Smith et al 2000;Li et al 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Large areas of farmland have been contaminated by arsenic (As) due to the irrigation with As-enriched groundwater or the contamination by mining and other activities (Zhu et al 2008b;Smith et al 2000;Li et al 2011). In paddy soils, As is released into soil solution mainly in the form of arsenite (As(III)), by As-reducing bacteria and by the reductive dissolution of iron oxyhydroxides which reduces the binding sites of As on minerals (Stroud et al 2011;Xu et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Arsenic bioavailability to rice plant in paddy soil: influence of microbial sulfate reduction

2015

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Purpose High arsenic (As) mobility in anaerobic paddy soil due to microbial Fe-and As-reducing processes results in As accumulation into rice plants. Sulfur (S) also undergoes microbial reducing processes in the anaerobic paddy soil, while this process interacts with the Fe-and As-reducing processes, forms secondary minerals, and thus influences As mobility in paddy soil. This work was carried out to investigate the role of sulfur and sulfate-reducing bacteria (SRB) in As redox transformation and bioavailability to rice plant in an anaerobic paddy soil. Materials and methods Anaerobic incubation experiments with or without sulfate (SO 4 2− ) and SRB were carried out to monitor S and iron (Fe) dynamics and their relations to As speciation and release to soil solution. Rice cultivation in pot experiment was then carried out to check the SO 4 2− amendment in bioavailability and uptake into rice plants.Results and discussion The inoculation of an enriched SRB community into the sterilized paddy soil increased reduction and release of As to the soil solution after flooding, showing its ability in arsenate (As(V)) as well as SO 4 2− reduction to arsenite (As(III)) and sulfide (S 2− ), respectively. Sulfate addition (2 and 100 mM) into the anaerobic paddy soil increased the reduction of SO 4 2− and ferric iron (Fe 3+ ) and resulted to lower dissolved As in the soil solution, which limited As mobility in the paddy soil. Application of SO 4 2− (100 mg kg −1 ) into paddy soil finally decreased the concentration of dissolved As in the soil solution by 23.5 % and also decreased As content in rice roots and iron plaque by 22.6 and 30.5 %, respectively. Conclusions The results revealed the important role of sulfur and the SRB activity in As speciation and mobility in anaerobic paddy soil, implying a lower As bioavailability to rice plants under sulfur-enriched anaerobic paddy soil, and an efficient way to reduce As accumulation in rice plants by sulfur fertilization in paddy soils.

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“…Rice consumption contributes a large proportion of inorganic As via dietary intake for those who rely on rice as the staple food [9][10][11]. The consumption of rice can contribute up to 60% of inorganic As ingestion through diet in China [11]. In addition, many people in the United States are also exposed to potentially harmful levels of As through rice consumption [12].…”

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confidence: 99%

“…Numerous studies have reported that the increase in soil As concentration can cause an enhancement of As accumulation in rice grain and in turn threaten human health through food chain [4][5][6][7][8]. Rice consumption contributes a large proportion of inorganic As via dietary intake for those who rely on rice as the staple food [9][10][11]. The consumption of rice can contribute up to 60% of inorganic As ingestion through diet in China [11].…”

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confidence: 99%

Effects of microbial processes on the fate of arsenic in paddy soil

2012

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Arsenic (As) is a metalloid toxic to organisms including humans. Arsenic in rice represents a significant exposure pathway for the general population, particularly for those subsisting on rice. Arsenic transformation, namely reduction, oxidation and methylation, in soil-rice systems has fundamental impacts on its mobility and toxicity. In addition to soil chemical properties (pH, Eh, metallic oxides, organic matter), microorganisms play critical roles in As transformation and mobility in paddy soil, such as through ArsM (As(III) S-adenosylmethyltransferase) and interactions with iron oxides or organic matters. Arsenic species in paddy soil directly influence As speciation in rice grain because the methylated As species in rice are mainly derived from microbial methylation in paddy soil. This paper aims to provide an overview on the status of the knowledge and gaps on the chemical aspects of As transformation in soil-rice system in conjunction with microbial ecology and functional genes. In addition, potential pathways (manipulation of microorganisms in paddy soil and genetic engineering) to decrease total As and/or inorganic As in rice grain are proposed.

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Inorganic arsenic in Chinese food and its cancer risk

Cited by 355 publications

References 39 publications

Arsenic Levels and Speciation from Ingestion Exposures to Biomarkers in Shanxi, China: Implications for Human Health

Arsenic Levels and Speciation from Ingestion Exposures to Biomarkers in Shanxi, China: Implications for Human Health

Arsenic bioavailability to rice plant in paddy soil: influence of microbial sulfate reduction

Effects of microbial processes on the fate of arsenic in paddy soil

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