Browsing by Author "Sommella, A."
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Item Global Sourcing of Low‑Inorganic Arsenic Rice Grain(Exposure and Health, 2019-11-12) Adomako, E.; Carey, M.; Meharg, C.; Williams, P.; Marwa, E.; Jiujin, X.; Farias, J.G.; De Silva, P.M.C.S.; Signes‑Pastor, A.; Lu, Y.; Nicoloso, F.T.; Savage, L.; Campbell, K.; Elliott, C.; Green, A.J.; Moreno‑Jiménez, E.; Carbonell‑Barrachina, A.A.; Triwardhani, E.A.; Pandiangan, F.I.; Haris, P.I.; Lawgali, Y.F.; Sommella, A.; Pigna, M.; Brabet, C.; Montet, D.; Njira, K.; Watts, M.J.; Meharg, A.A.Arsenic in rice grain is dominated by two species: the carcinogen inorganic arsenic (the sum of arsenate and arsenite) and dimethylarsinic acid (DMA). Rice is the dominant source of inorganic arsenic into the human diet. As such, there is a need to identify sources of low-inorganic arsenic rice globally. Here we surveyed polished (white) rice across representative regions of rice production globally for arsenic speciation. In total 1180 samples were analysed from 29 distinct sampling zones, across 6 continents. For inorganic arsenic the global ̃x was 66 μg/kg, and for DMA this figure was 21 μg/kg. DMA was more variable, ranging from < 2 to 690 μg/kg, while inorganic arsenic ranged from < 2 to 399 μg/kg. It was found that inorganic arsenic dominated when grain sum of species was < 100 μg/kg, with DMA dominating at higher concentrations. There was considerable regional variance in grain arsenic speciation, particularly in DMA where temperate production regions had higher concentrations. Inorganic arsenic concentrations were relatively consistent across temperate, subtropical and northern hemisphere tropical regions. It was only in southern hemisphere tropical regions, in the eastern hemisphere that low-grain inorganic arsenic is found, namely East Africa ( ̃x < 10 μg/kg) and the Southern Indonesian islands ( ̃x < 20 μg/kg). Southern hemisphere South American rice was universally high in inorganic arsenic, the reason for which needs further exploration.Item Lead in rice: Analysis of baseline lead levels in market and field collected rice grains(Science of the Total Environment, 2014-07) Norton, G.J.; Williams, P.N.; Adomako, E.E.; Price, A.H.; Zhu, Y.; Zhao, F.-J.; McGrath, S.; Deacon, C.M.; Villada, A.; Sommella, A.; Lu, Y.; Ming, L.; De Silva, P.M.C.S.; Brammer, H.; Dasgupta, T.; Islam, M.R.; Meharg, A.A.In a large scale survey of rice grains from markets (13 countries) and fields (6 countries), a total of 1578 rice grain samples were analysed for lead. From the market collected samples, only 0.6% of the samples exceeded the Chinese and EU limit of 0.2μgg-1 lead in rice (when excluding samples collected from known contaminated/mine impacted regions). When evaluating the rice grain samples against the Food and Drug Administration's (FDA) provisional total tolerable intake (PTTI) values for children and pregnant women, it was found that only people consuming large quantities of rice were at risk of exceeding the PTTI from rice alone. Furthermore, 6 field experiments were conducted to evaluate the proportion of the variation in lead concentration in rice grains due to genetics. A total of 4 of the 6 field experiments had significant differences between genotypes, but when the genotypes common across all six field sites were assessed, only 4% of the variation was explained by genotype, with 9.5% and 11% of the variation explained by the environment and genotype by environment interaction respectively. Further work is needed to identify the sources of lead contamination in rice, with detailed information obtained on the locations and environments where the rice is sampled, so that specific risk assessments can be performed. © 2014 Elsevier B.V.Item Variation in rice cadmium related to human exposure(Environmental Science and Technology, 2013-05) Meharg, A.A.; Norton, G.; Deacon, C.; Williams, P.; Adomako, E.E.; Price, A.; Zhu, Y.; Li, G.; Zhao, F.J.; McGrath, S.; Villada, A.; Sommella, A.; De Silva, P.M.C.S.; Brammer, H.; Dasgupta, T.; Islam, M.R.Cereal grains are the dominant source of cadmium in the human diet, with rice being to the fore. Here we explore the effect of geographic, genetic, and processing (milling) factors on rice grain cadmium and rice consumption rates that lead to dietary variance in cadmium intake. From a survey of 12 countries on four continents, cadmium levels in rice grain were the highest in Bangladesh and Sri Lanka, with both these countries also having high per capita rice intakes. For Bangladesh and Sri Lanka, there was high weekly intake of cadmium from rice, leading to intakes deemed unsafe by international and national regulators. While genetic variance, and to a lesser extent milling, provide strategies for reducing cadmium in rice, caution has to be used, as there is environmental regulation as well as genetic regulation of cadmium accumulation within rice grains. For countries that import rice, grain cadmium can be controlled by where that rice is sourced, but for countries with subsistence rice economies that have high levels of cadmium in rice grain, agronomic and breeding strategies are required to lower grain cadmium. © 2013 American Chemical Society.