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Abstract: The importance or otherwise of rice as an exposure pathway for As ingestion by people living in Bengal and other areas impacted by hazardous As-bearing groundwaters is currently a matter of some debate. Here this issue is addressed by determining the overall increased cancer risk due to ingestion of rice in an As-impacted district of West Bengal. Human target cancer health risks have been estimated through the intake of As-bearing rice by using combined field, laboratory and computational methods. Monte Carlo simulations were run following fitting of model probability curves to measured distributions of (i) As concentration in rice and drinking water and (ii) inorganic As content of rice and fitting distributions to published data on (i) ingestion rates and (ii) body weight and point estimates on bioconcentration factors, exposure duration and other input variables. The distribution of As in drinking water was found to be substantially lower than that reported by previous authors for As in tube wells in the same area, indicating that the use of tube well water as a proxy for drinking water is likely to result in human health risks being somewhat overestimated. The calculated median increased lifetime cancer risk due to cooked rice intake was 7.62×10−4, higher than the 10−4–10−6 range typically used by the USEPA as a threshold to guide determination of regulatory values and similar to the equivalent risk from water intake. The median total risk from combined rice and water intake was 1.48×10−3. The contributions to this median risk from drinking water, rice and cooking of rice were found to be 48%, 44% and 8%, respectively. Thus, rice is a major potential source of As exposure in the As-affected study areas in West Bengal and the most important exposure pathway for groups exposed to low or no As in drinking water. [Copyright &y& Elsevier]

Epidemiological studies have associated chronic exposure to arsenic (As) from drinking water with increased risk of hypertension. However, evidence of an association between As exposure from food and hypertension risks is sparse. To quantify the association between daily As intake from both food (rice, wheat and potatoes) and drinking water (As water) along with total exposure (As total) and hypertension risks in a study population in Bihar, India, we conducted an individual level cross-sectional analysis between 2017 and 2019 involving 150 participants. Arsenic intake variables and three indicators of hypertension risks (general hypertension, low-density lipoprotein (LDL) and high-density lipoprotein (HDL)) were derived, and any relationship was quantified using a series of crude and multivariable log-linear or logistic regression models. The prevalence of general hypertension was 40% for the studied population. The median level of HDL was 45 mg/dL while median value of LDL was 114 mg/dL. Apart from a marginally significant positive relationship between As intake from rice and the changes of LDL (p-value = 0.032), no significant positive association between As intake and hypertension risks could be ascertained. In fact, As total was found to be associated with lower risks of general hypertension and higher levels of HDL (p-value = 0.020 and 0.010 respectively) whilst general hypertension was marginally associated with lower As water (p-value = 0.043). Due to limitations regarding study design and residual confounding, all observed marginal associations should be treated with caution. • Cross-sectional study of hypertension risks associated with arsenic exposure from food and drinking water. • Total median arsenic intake of 36 µg/day for the study population in Bihar, India. • Total arsenic intake marginally associated with lower risks of general hypertension and higher levels of HDL. • Marginal positive relationship between arsenic intake from rice and level of LDL. • Limitations regarding study design and residual confounding problems should not be neglected. [ABSTRACT FROM AUTHOR]

Arsenic (As) exposure from surface and groundwater in Peru is being recognised as a potential threat but there are limited studies on As in the food-chain and none on As in Peruvian rice. In this study, we have determined the As content in rice cultivated in the Tumbes river basin located in the northern province of Peru, an area known for extensive rice cultivation. We collected rice and soil samples from agricultural fields, soil was collected using grid sampling technique while rice was collected from the heaps of harvested crop placed across the fields. The average total As concentration in rice was 167.94 ± 71 μg kg−1 (n = 29; range 68.39–345.31 μg kg−1). While the rice As levels were not highly elevated, the As content of few samples (n = 7) greater than 200 μg kg−1 could contribute negatively to human health upon chronic exposure. Average concentration of As in soil was 8.63 ± 7.8 mg kg−1 (n = 30) and soil to grain transfer factor was 0.025 ± 0.018 for 12 matched samples. Compared to our previous pilot study in 2006 (samples collected from the same agricultural fields but not from exact locations) there was a 41% decrease in As soil concentration in this study. Rice samples collected in 2006 (n = 5) had a mean concentration of 420 ± 109 μg kg−1. Our data provides a baseline of rice grain As concentrations in Peruvian province of Tumbes and warrants further studies on factors affecting uptake of As by the rice varieties cultivated in Peru and any potential human health risks. Image 1 • First study reporting arsenic concentrations in rice cultivated in Peru. • Rice production in Peru is on the rise. • Puyango-Tumbes river has elevated concentrations of arsenic and other heavy metals. • Further assessment of arsenic in rice cultivated in Tumbes river basin is of significance. [ABSTRACT FROM AUTHOR]

In the UK, consumption of rice and rice-based products is on the rise but, notwithstanding public expressed concerns about such products as an exposure route for arsenic (e.g., BBC News report, 2017 'Should I worry about arsenic in my rice?') there are few, if any published data on public perceptions of risks associated with exposure to arsenic in rice. We therefore aimed to determine the risk perception of arsenic exposure from rice intake and factors that are associated with arsenic knowledge and whether or not this knowledge had an influence on rice consumption and cooking practices. A questionnaire, targeting participation of rice-eating ethnic minorities in Greater Manchester, UK, was administered to 184 participants. A multivariate generalised linear model was used to determine the factors associated with rice consumption behaviour, cooking practices, and risk perception. We show for the first time that the general population did not associate arsenic, which they perceive as toxic to health, with rice consumption. More than half of the participants knew about arsenic as a hazardous substance but less than ten percent knew that rice consumption could be an important route of arsenic exposure. Knowledge of arsenic was significantly lower in Asian/Asian British:Pakistanis (Pakistani) (OR: 0.006; 95% CI:0.00–0.03) and Asian/Asian British:Bangladeshis (Bangladeshi) (OR: 0.064; 95% CI:0.01–0.25) compared to White:English/Welsh/Scottish/Northern Irish/British (White British). Moreover, Bangladeshis consumed three times more rice (OR: 2.92; 95% CI:1.73–4.93) compared to White British. Overall higher rice consumption was not associated with higher knowledge of the nutritional value of rice. Rinsing rice before cooking, an effective arsenic removal technique, was practised by 93% of the participants; however, the most popular cooking method was the use of adequate water (rice to water ratio of 1:2) but not excess water (rice to water ratio of >1:4), the latter being more effective in removing arsenic. Better education, higher weekly expenditure on food and prior knowledge of arsenic hazard were all significant factors positively influencing a change in behaviour to reduce arsenic exposure from rice intake. [ABSTRACT FROM AUTHOR]

Arsenic (As) accumulation in rice grain and subsequent transmission into the food chain is a major global concern. Numerous attempts to minimize As accumulation in rice have been researched till date. The current investigation evaluates the relative susceptibility of different growth stages of rice plant to As stress in terms of As accumulation in grain at maturity using sixty treatment combinations. Our findings suggest that supplementing with selenium (Se) resulted in minimizing As content significantly (at P < 0.001 level) in grain, irrespective of growth stages where As stress was introduced. The findings registered the following order of susceptibility to As stress: flowering > grain filling > maximum tillering. Our findings also showed that Se primed rice plants restricts majority of As accumulation in the root itself and minimizes As translocation to the above ground part. The results of this study shows that cultivation of Se primed seeds can be (i) an effective means to minimize As accumulation in rice, and (ii) potential mode of biofortification of rice grain with essential nutrient elements {iron (8.47–10.17 mg L-1), zinc (7.14–8.05 mg L-1), manganese (17.92–19.71 mg L-1) and copper (3.18–3.28 mg L-1)} improving the recommended dietary intake of micronutrients, an invaluable strategy especially for malnourished rice dependent populations. Using machine learning this study also predicts that the Se concentration of 0.862 mg L−1 could be the most effective input in minimizing As content and enhancing other micronutrient content, irrespective of As stress. • Flowering stage was most prone to As stress and responsible for highest As content at maturity. • Brown rice from Se primed plants contained more essential nutrients and less As. • Growing Se primed rice seeds could be an alternative farmer friendly mean to fortification. • 0.862 mg Se L−1 emerged out to be threshold concentration for seed priming treatment. [ABSTRACT FROM AUTHOR]

In Zamfara state, Nigeria, rice is cultivated in fields contaminated with Pb (lead) from artisanal and illicit mining activities. Rice grown in such contaminated agricultural areas risks not only Pb contamination but also contamination from other toxic elements, like arsenic (As); co-contamination of Pb and As in rice cultivated in mining impacted areas has been previously reported and rice is a hyperaccumulator of As. A field study was conducted with ten different commonly-cultivated Nigerian rice varieties in the mining-impacted farmlands of Dareta village, Zamfara State. The aim was to determine the optimal rice variety for cultivation on these contaminated farmlands; an optimal variety would have the lowest contaminant concentrations and highest essential elements concentrations in the rice grains. A total of 300 paired soil and rice plants were collected. The mean As and Pb concentrations in paddy soils were 0.91 ± 0.82 mg kg−1 and 288.5 ± 464.2 mg kg−1, respectively. Mean As (30.4 ± 15.1 μg kg−1) content in rice grains was an order of magnitude lower than the Codex recommendation of 200 μg kg−1 (for milled rice) while the Pb content in all the rice varieties (overall mean of 743 ± 327 μg kg−1) was approximately four times higher than the Codex recommendation of 200 μg kg−1. Contrary to previous studies, a negative correlation was observed between As and Pb in rice grains across all the varieties. Rice variety Bisalayi was the variety with the lowest Pb transfer factor (TF = 0.08), but the average Pb concentration in rice grain was still above the Codex recommendation. Bisalayi also had the highest TF for iron. Variety ART_15, which had the lowest As uptake (TF = 0.10), had the highest TF for essential elements (magnesium, potassium, manganese, zinc, and copper). In areas of Pb contamination, Bisalayi rice may therefore be a suitable variety to choose for cultivation. [Display omitted] • First study on influence of rice variety on Pb and As co-uptake in Zamfara, Nigeria. • Cultivation of rice is on the rise in mining-impacted farmlands of Zamfara State. • Mean Pb content in all ten rice varieties was far above the Codex recommendation. • Negative correlation between As and Pb in rice grains was observed. [ABSTRACT FROM AUTHOR]