Rice consumption contributes to low level methylmercury exposure in southern China

Li, Ping; Feng, Xinbin; Yuan, Xiaobo; Chan, Hing Man; Qiu, Guangle; Sun, Guoxin; Zhu, Yan

doi:10.1016/j.envint.2012.08.006

Cited by 97 publications

(54 citation statements)

References 38 publications

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“…From Table 1 references, data were excluded for rice purchased in Saudi Arabia (reference #1, Al-Saleh and Shinwari, 2001), Spain (from Japan and Thailand, reference #8, Da Silva et al, 2010), France (reference #18, Leblanc et al, 2004), and rice cultivated or purchased in multiple provinces in China (reference # 10, Fang et al, 2014; reference #23, Li P., et al, 2012; reference #32, Qian et al, 2010). All other data from studies in Table 1 were mapped.…”

Section: Figurementioning

confidence: 99%

Rice methylmercury exposure and mitigation: A comprehensive review

Rothenberg

Windham‐Myers

Creswell

2014

Environmental Research

167

151

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Rice cultivation practices from field preparation to post-harvest transform rice paddies into hot spots for microbial mercury methylation, converting less-toxic inorganic mercury to more-toxic methylmercury, which is likely translocated to rice grain. This review includes 51 studies reporting rice total mercury and/or methylmercury concentrations, based on rice cultivated or purchased in 15 countries. Not surprisingly, both rice total mercury and methylmercury levels were significantly higher in polluted sites compared to non-polluted sites (Wilcoxon rank sum, p<0.001). However, rice percent methylmercury (of total mercury) did not differ statistically between polluted and non-polluted sites (Wilcoxon rank sum, p=0.35), suggesting comparable mercury methylation rates in paddy soil across these sites and/or similar accumulation of mercury species for these rice cultivars. Studies characterizing the effect of rice cultivation under more aerobic conditions were reviewed to determine the mitigation potential of this practice. Rice management practices utilizing alternating wetting and drying (instead of continuous flooding) caused soil methylmercury levels to spike, resulting in a strong methylmercury pulse after fields were dried and reflooded; however, it is uncertain whether this led to increased translocation of methylmercury from paddy soil to rice grain. Due to the potential health risks, it is advisable to investigate this issue further, and to develop separate water management strategies for mercury polluted and non-polluted sites, which minimize methylmercury exposure through rice ingestion.

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Section: Figurementioning

confidence: 99%

Rice methylmercury exposure and mitigation: A comprehensive review

Rothenberg

Windham‐Myers

Creswell

2014

Environmental Research

167

151

View full text Add to dashboard Cite

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“…34 China is the largest rice producer with 30.7% of the global production, and southern China is the main rice cultivation region accounting for 93% of national rice production. 35 In contrast, northern China is too cold and dry for rice cultivation; wheat, rather than rice, is the staple food of the populations of this region. It was estimated in 2007 that the amount of insecticides used in Jiangsu province was nearly three times of that in Shandong province (140 vs 50 thousand tons).…”

Section: Pyrethroid Insecticide Exposure In Northern Chinamentioning

confidence: 99%

Prenatal exposure to pyrethroid insecticides and birth outcomes in Rural Northern China

Ding

Cui

Chen

et al. 2014

J Expo Sci Environ Epidemiol

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Although pyrethroid insecticides are widely used, little is known about potential adverse effects on fetal growth. Participating 454 mother-infant pairs were recruited from a prospective birth cohort in rural northern China between September 2010 and 2012. We measured five non-specific pyrethroid metabolites in maternal urine at delivery and examined their association with birth outcomes including birth weight, length, head circumference, and gestational duration. The creatinine-adjusted medians of pyrethroid metabolites in urine were 0.51 μg/g for cis-DCCA, 0.65 μg/g for trans-DCCA, and 0.68 μg/g for 3-PBA. The pregnant women had substantially higher levels of urinary pyrethroid metabolites compared with those reported in developed countries. A increase in total (the sum of cis-DCCA, trans-DCCA, and 3-PBA) but not individual urinary metabolite levels was associated with a decrease in birth weight (adjusted β=-96.76 g per log10 unit increase, 95% confidence interval=-173.15 to -20.37). No associations were found between individual or total metabolite levels and birth length, head circumference, or gestational duration. We report an adverse association of prenatal exposure to pyrethroids as measured by urinary metabolites with birth weight. More studies are warranted in China given the relatively high levels of urinary metabolites in our study population.

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“…The Wanshan Hg mine is the biggest Hg mine in Asia and has caused serious Hg contamination of the local environment and adjacent ecosystems. Although many studies have been conducted across the Hg mining area on the health risks of Hg exposure [27][28][29], limited knowledge is available on the effects of long-term Hg contamination on bacterial community composition in the paddy soils. The paddy soil is a typical anaerobic habitat, where microorganisms could play key roles in both Hg reduction and methylation [15,30].…”

Section: Introductionmentioning

confidence: 99%

Patterns of Bacterial Diversity Along a Long-Term Mercury-Contaminated Gradient in the Paddy Soils

et al. 2014

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Mercury (Hg) pollution is usually regarded as an environmental stress in reducing microbial diversity and altering bacterial community structure. However, these results were based on relatively short-term studies, which might obscure the real response of microbial species to Hg contamination. Here, we analysed the bacterial abundance and community composition in paddy soils that have been potentially contaminated by Hg for more than 600 years. Expectedly, the soil Hg pollution significantly influenced the bacterial community structure. However, the bacterial abundance was significantly correlated with the soil organic matter content rather than the total Hg (THg) concentration. The bacterial alpha diversity increased at relatively low levels of THg and methylmercury (MeHg) and subsequently approached a plateau above 4.86 mg kg −1 THg or 18.62 ng g −1 MeHg, respectively. Contrasting with the general prediction of decreasing diversity along Hg stress, our results seem to be consistent with the intermediate disturbance hypotheses with the peak biological diversity under intermediate disturbance or stress. This result was partly supported by the inconsistent response of bacterial species to Hg stress. For instance, the relative abundance of Nitrospirae decreased, while that of Gemmatimonadetes increased significantly along the increasing soil THg and MeHg concentrations. In addition, the content of SO 4 2− , THg, MeHg and soil depth were the four main factors influencing bacterial community structures based on the canonical correspondence analysis (CCA). Overall, our findings provide novel insight into the distribution patterns of bacterial community along the long-term Hg-contaminated gradient in paddy soils.

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Rice consumption contributes to low level methylmercury exposure in southern China

Cited by 97 publications

References 38 publications

Rice methylmercury exposure and mitigation: A comprehensive review

Rice methylmercury exposure and mitigation: A comprehensive review

Prenatal exposure to pyrethroid insecticides and birth outcomes in Rural Northern China

Patterns of Bacterial Diversity Along a Long-Term Mercury-Contaminated Gradient in the Paddy Soils

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