Andrew A. Meharg's research while affiliated with Queen's University Belfast and other places

Publications (428)

Article
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Rice is a major source for micro-elements for the Sri Lankan population, across all agro-climatic zones. This current study was conducted to investigate the variation of the metal(loid)s and As speciation in rice grains collected from wet, intermediate and dry zones of Sri Lanka. Field rice (brown rice) and market rice (polished rice) samples were...
Article
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International food trade is fundamental to global food security but with often negative consequences in the producing country. We propose a method of quantifying flows of inorganic arsenic (iAs) and embedded increased lifetime cancer risks (EHR) at a global scale, where negative impacts are felt on the importing country. Computations were made for...
Article
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Despite the centrality of staple grains for human well-being, both as a source of nutrients and of toxic ions, there is little understanding of where and how elements vary, and if there are particular elements that correlate. Here, for shop bought polished (white) rice we comprehensively characterize trace (arsenic species, cadmium, copper, iron, m...
Preprint
Full-text available
Despite the centrality of staple grains for human well-being, both as a source of nutrients and of toxic ions, there is little understanding of where and how elements vary, and if there are particular elements that correlate. Here, for shop bought polished (white) rice we comprehensively characterize trace (arsenic species, cadmium, copper, iron, m...
Article
Full-text available
Cadmium in the diet is of concern as it is a renal toxicant and a carcinogen, with a half-life in the body measured in decades. Inorganic arsenic is a chronic carcinogen. For many subpopulations, rice and rice products may be the dominate source of cadmium and inorganic arsenic. In particular, rice porridge, cereal and cake are widely used to feed...
Article
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Paddy soils in Bangladesh experience extensive irrigation with groundwater and surface water, both having variable geochemical constituents. The soils also have topological variations across the landscape. To understand the geochemical variability in the soils as affected by the different sources of irrigation water and the topographical variabilit...
Article
Fertilization with organic matter (farm yard manure and/or rice straw) is thought to enhance arsenic (As) mobilization into soil porewaters, with subsequent As assimilation by rice roots leading to enhanced translocation to the grain. Here, interlinked experiments (field manuring and soil batch culture) were conducted to find the effect of organic...
Article
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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 acros...
Article
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Exposure to certain arsenic (As) species has been associated with increased cancer risk and a wide range of other health concerns, even at low levels. Here we used urine as a biomarker of As internal dose in a well-characterized cohort to relate diet, demographics and geography to exposure. As speciation in spot urine samples was determined for 89...
Article
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One of cadmium’s major exposure routes to humans is through rice consumption. The concentrations of cadmium in the global polished (white), market rice supply-chain were assessed in 2270 samples, purchased from retailers across 32 countries, encompassing 6 continents. It was found on a global basis that East Africa had the lowest cadmium with a med...
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The last column in Table 1, “As air conc.” is not used in the text and was included by mistake.
Article
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Geochemical relationships and the contamination of arsenic in surface soils of the Haor basin, a low lying semi-natural region to the northeast of Bangladesh, were assessed. These semi-natural Haor soils have continuity with underlying sediments that release arsenic into groundwater. The arsenic content in the surface soils of the study area ranged...
Article
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Purpose The trace element iodine is a vital constituent of thyroid hormones. Iodine requirements increase during pregnancy, when even mild deficiency may affect the neurocognitive development of the offspring. Urinary iodine concentration (UIC) is the means of assessing iodine status in population surveys; a median UIC of 100–199 µg/L is deemed suf...
Article
Cadmium, inorganic arsenic and, potentially, dimethyl arsenic acid are carcinogens widely elevated in rice. Here it was identified that the food-safe and common cadmium chelator citric acid efficiently removed cadmium from intact grain via pre-soaking procedure, while also reducing arsenic species. A twostep pre-soaking stage was developed whereby...
Article
Diets worldwide are deficient in iodine, leading to a range of undesirable health effects at the population level. Dairy products are a primary source of iodine in diets for those populations in which iodized salt is not systematically used or available. However, the flows of iodine through dairy agroecosystems are not well understood. The aim of t...
Article
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The source identification of trace elements in peri-urban soils has not been fully explored, especially for the areas in eastern China. Here, 80 soil samples, including 40 from cropland, 11 from orchards and 29 from forests, were collected in a typical peri-urban catchment, Ningbo, eastern China. The concentrations of arsenic (As), cadmium (Cd), ch...
Chapter
Abstract Presence of arsenic in paddy soils in Bangladesh has become a major concern, with Holocene soils reported to have higher levels of arsenic compared to Pleistocene. However, to date there is limited data on how geomorphology, land use and soil microbes drive bioavailability of arsenic in the paddy soil in Bangladesh. In the present study,...
Article
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Human exposure to As through rice consumption is a worldwide health concern. There is an urgent need to either remediate As contaminated paddy soils, or to screen for low As accumulating rice varieties, thereby limiting the build up of As in their grains. This review presents a number of agronomic, physico-chemical, and biological approaches that m...
Article
The speciation of arsenic in wet and dry deposition are ambiguously described in current literature. Presented here is a 2 year study quantifying arsenic species in atmospheric deposition collected daily from an E. Atlantic coastal, semirural site, with comparative urban locations. Inorganic arsenic (Asi) was the principal form of arsenic in wet de...
Article
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Human exposure to arsenic (As) through the consumption of rice (Oryza sativa L.) is a worldwide health concern. In this paper, we evaluated the major causes for high inorganic As levels in cooked rice foods, and the potential of post-harvesting and cooking options for decreasing inorganic As content in cooked rice, focusing particularly on As endem...
Article
Using village-based rice processing plants in rural Bangladesh, this study considered how parboiling rice could be altered to reduce the content of the carcinogen inorganic arsenic. Parboiling is normally conducted with rough rice (i.e., where the husk is intact) that is soaked overnight at ambient temperatures, and then either steamed or boiled fo...
Article
Early-life exposure to inorganic arsenic (iAs)may adversely impact health later in life. To date, evidence of iAs adverse effects on children's neurodevelopment comes mainly from populations highly exposed to contaminated water with conflicting results. Little is known about those effects among populations with low iAs exposure from food intake. We...
Article
The interplay between rice roots and manuring with respect to arsenic speciation, subsequent assimilation into roots, and translocation to shoots in paddy soil was investigated, alongside bacterial diversity characterization. Planting increased soil Eh and decreased soil solution arsenic species: inorganic arsenic (iAs), monomethylarsonic acid (MMA...
Article
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The environmental and human health risk posed by veterinary antibiotics is of global concern. Antibiotic uptake by herbal plants has been studied, but little is known about perennial woody fruit crops. Litchi (Litchi chinensis Sonn.), a longevial fruit tree, is routinely fertilized with animal manure and, therefore, may be at risk of antibiotic upt...
Article
Due to its serious health risks, lead (Pb) in rice, specifically its uptake, translocation, and accumulation mechanisms and its toxic effects have been studied intensively in recent years. However, it remains unclear about the role of phytolith, a siliceous structure in rice plants, in the storage and release kinetics of Pb in rice. This study aims...
Article
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The diet is emerging as the dominant source of arsenic exposure for most of the U.S. population. Despite this, limited regulatory efforts have been aimed at mitigating exposure, and the role of diet in arsenic exposure and disease processes remains understudied. In this brief, we discuss the evidence linking dietary arsenic intake to human disease...
Preprint
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Although arsenic is generally a toxic compound, there are a number of ferns in the genus Pteris that can tolerate large concentrations of this metalloid. In order to probe the mechanisms of arsenic hyperaccumulation, we expressed a Pteris vittata cDNA library in an Escherichia coli ΔarsC (arsenate reductase) mutant. We obtained three independent cl...
Article
Rice is the main staple carbohydrate source for billions of people worldwide. Natural geogenic and anthropogenic sources has led to high arsenic (As) concentrations in rice grains. This is because As is highly bioavailable to rice roots under conditions in which rice is cultivated. A multifaceted and interdisciplinary understanding, both of short-t...
Article
Hypoallergenic formulas are recommended for use in young children with cow's milk protein allergy (CMPA), where breastmilk is not available,¹ with the choice between both extensively hydrolysed casein/whey or amino acid‐based products. More recently, hydrolysed rice protein‐based formulas (HRF) have become available and are now commonly used in Eur...
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Background Plants can adapt to edaphic stress, such as nutrient deficiency, toxicity and biotic challenges, by controlled transcriptomic responses, including microbiome interactions. Traditionally studied in model plant species with controlled microbiota inoculation treatments, molecular plant-microbiome interactions can be functionally investigate...
Article
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There has been an increasing realisation that young infants are exposed to elevated concentrations of the carcinogen inorganic arsenic, relative to adults. This is because many infant food products are rice based, and rice is ~10-fold elevated in inorganic arsenic compared to most other foods. The European Commission (EC) has acted on this concern...
Data
Sample information and arsenic speciation for individual samples, and means per sample type. The file contains an Excel sheet with data tabulated under the tabs: “product class medians”, “product averages” and “all sample details”. (XLSX)
Article
Marine sources of arsenic to the atmosphere are normally dismissed as minor. Here we show that arsenic can be biovolatilized from coastal seawaters, and that biovolatilzation is regulated by organic arsenic species present in the seawater. Even though inorganic arsenic is in great excess in seawaters, it is trimethylarsine (TMA) that is the primary...
Article
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In recent time, phytoliths (silicon deposition between plant cells) have been recognized as an important nutrient source for crops. The work presented here aims at highlighting the potential of phytolith-occluded K pool in ferns. Dicranopteris linearis (D. linearis) is a common fern in the humid subtropical and tropical regions. Burning of the fern...
Article
We measured the bulk grain concentrations of arsenic (As), along with rubidium (Rb) and strontium (Sr) as indicators of phloem and xylem transport respectively, in rice (Oryza sativa cv. Italica Carolina) pulsed with arsenate (As(V)) at two exposure concentrations for 5 day periods at progressively later stages of grain fill, between anthesis and m...
Article
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Iron (Fe) deficiency is a serious agricultural problem, particularly for alkaline soils. Secretion of coumarins by Arabidopsis thaliana roots is induced under Fe-deficiency. An essential enzyme for the biosynthesis of major Arabidopsis coumarins, scopoletin and its derivatives, is Feruloyl-CoA 6'-Hydroxylase1 (F6'H1), that belongs to a large enzyme...
Article
Inorganic arsenic (i-As) has been related to wide-ranging health effects in children, leading to lifelong concerns. Proportionally, dietary i-As exposure dominates in regions with low arsenic drinking water. This study aims to investigate the relation between rice and seafood consumption and urinary arsenic species during childhood and to assess th...
Preprint
Full-text available
Highlight A strongly iron-responsive gene of previously unknown function, At3g12900, encodes a scopoletin 8-hydroxylase involved in coumarin biosynthesis and plays an important role in the iron uptake strategy in Arabidopsis. Abstract Iron (Fe) deficiency represents a serious agricultural problem, particularly in alkaline soils. Secretion of couma...
Article
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Arsenic speciation, their inputs, for wet deposition are not well understood. Here we demonstrate that trimethylarsine oxide (TMAO) and inorganic arsenic are the dominant species in summer, Indian subcontinent, Bangladesh, monsoonal, wet deposition, with inorganic arsenic dominating, accounting for ~80% of total arsenic in this medium. Lower concen...
Article
Rice plants grown on soils with elevated arsenic have been shown to have increased arsenic content in their grains. To gain a better understanding of the likelihood of high grain arsenic in rice grown in different soils, it is important to understand the factors affecting the bioavailability and mobility of arsenic. Paddy soils from six different p...
Article
Silicon (Si) is assimilated from soil by rice and is deposited in shoots in inter- and intracellularly, resulting in the formation of silicaceous structures, namely phytoliths. During the precipitation of Si, elements present in xylem/phloem sap, including phosphorus (P), can also be occluded in the phytolith. We examined the release of Si and P fr...