Global sourcing of low-inorganic arsenic rice grain

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 ~ 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 ~ x~  < 10 μg/kg) and the Southern Indonesian islands (x ~ x~  < 20 μg/kg). Southern hemisphere South American rice was universally high in inorganic arsenic, the reason for which needs further exploration

Rice grain cadmium concentrations in the global supply-chain

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 median for both Malawi and Tanzania at 4.9 μg/kg, an order of magnitude lower than the highest country, China with a median at 69.3 μg/kg. The Americas were typically low in cadmium, but the Indian sub-continent was universally elevated. In particular certain regions of Bangladesh had high cadmium, that when combined with the high daily consumption rate of rice of that country, leads to high cadmium exposures. Concentrations of cadmium were compared to the European Standard for polished rice of 200 μg/kg and 5% of the global supply-chain exceeded this threshold. For the stricter standard of 40 μg/kg for processed infant foods, for which rice can comprise up to 100% by composition (such as rice porridges, puffed rice cereal and cakes), 25% of rice would not be suitable for making pure rice baby foods. Given that rice is also elevated in inorganic arsenic, the only region of the world where both inorganic arsenic and cadmium were low in grain was East Africa

Kidney diseases in agricultural communities : a case against heat-stress nephropathy

The beginning of the 21st century has seen the emergence of a new chronic tubulo-interstitial kidney disease of uncertain cause among agricultural communities in Central America and Sri Lanka. Despite many similarities in demography, presentation, clinical features, and renal histopathology in affected individuals in these regions, a toxic etiology has been considered mainly in Sri Lanka, whereas the predominant hypothesis in Central America has been that recurrent acute kidney injury (AKI) caused by heat stress leads to chronic kidney disease (CKD). This is termed the heat stress/dehydration hypothesis. This review attempts to demonstrate that there is sparse evidence for the occurrence of significant AKI among manual workers who are at high risk, and that there is little substantial evidence that an elevation of serum creatinine < 0.3 mg/dl in previously healthy people will lead to CKD even with recurrent episodes. It is also proposed that the extent of global warming over the last half-century was not sufficient to have caused a drastic change in the effects of heat stress on renal function in manual workers. Comparable chronic tubulo-interstitial kidney disease is not seen in workers exposed to heat in most tropical regions, although the disease is seen in individuals not exposed to heat stress in the affected regions. The proposed pathogenic mechanisms of heat stress causing CKD have not yet been proved in humans or demonstrated in workers at risk. It is believed that claims of a global warming nephropathy in relation to this disease may be premature and without convincing evidence

Applicability of Novel Urinary Biomarkers for the Assessment of Renal Injury in Selected Occupational Groups in Sri Lanka: A Comparative Study with Conventional Markers

Screening approaches with more robust biomarkers, are of the utmost importance in the characterization of renal injuries, particularly among communities with high burdens of chronic kidney disease of uncertain etiology (CKDu). The present study aimed to assess the utility of two emerging biomarkers: kidney injury molecule (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) in predicting renal injury in different occupational groups in Sri Lanka. A cross-sectional study was conducted with six occupational groups (n = 188): fisherfolk (FF), paddy farmers (PF), sugarcane farmers (SF), factory workers (FW) and plantation workers (PW) to assess the predictive performance of KIM-1 and NGAL against a CKDu patient (PT) group (n = 40). The median KIM-1 levels of the study groups; FF, PF, SF, FW, PW and PT were 0.67, 0.59, 0.49, 1.62, 0.67 and 5.24 ng/mgCr, respectively, while the median NGAL levels were 1.16, 2.52, 1.42, 1.71, 1.06 and 22.41 ng/mgCr respectively. In ROC analysis to predict CKDu susceptibility, the area under the curve for KIM-1 ranged from 0.88 to 0.99 for the study groups, and in overall analysis, the sensitivity and specificity were 100% and 96%, respectively, for a cutoff value of 2.76 ng/mgCr. Similarly, for NGAL the range of AUC was 0.78&ndash;0.94, and a cutoff value of 3.12 ng/mgCr produced 88% sensitivity and 82% specificity. Compared with conventional markers, KIM-1 was the best biomarker for the characterization of renal injury in the participants of the occupational groups. With further validations, KIM-1 may be adopted as a prognostic marker to identify early renal injury and CKDu susceptibilities in community screening

Elevated trimethylarsine oxide (TMAO) and inorganic arsenic in northern hemisphere summer monsoonal wet deposition

For arsenic speciation, the inputs for wet deposition are not well understood. Here we demonstrate that trimethylarsine oxide (TMAO) and inorganic arsenic are the dominant species in monsoonal wet deposition in the summer Indian subcontinent, Bangladesh, with inorganic arsenic dominating, accounting for ∼80% of total arsenic in this medium. Lower concentrations of both species were found in monsoonal wet deposition in the winter Indian subcontinent, Sri Lanka. The only other species present was dimethylarsinic acid (DMAA), but this was usually below limits of detection (LoD). We hypothesize that TMAO and inorganic arsenic in monsoonal wet deposition are predominantly of marine origin. For TMAO, the potential source is the atmospheric oxidation of marine derived trimethylarsine. For inorganic arsenic, our evidence suggests entrainment of water column inorganic arsenic into atmospheric particulates. These conclusions are based on weather trajectory analysis and on the strong correlations with known wet deposition marine derived elements: boron, iodine, and selenium. The finding that TMAO and inorganic arsenic are widely present and elevated in monsoonal wet deposition identifies major knowledge gaps that need to be addressed regarding the understanding of arsenic’s global cycle

Elevated Trimethylarsine Oxide and Inorganic Arsenic in Northern Hemisphere Summer Monsoonal Wet Deposition

For arsenic speciation, the inputs for wet deposition are not well understood. Here we demonstrate that trimethylarsine oxide (TMAO) and inorganic arsenic are the dominant species in monsoonal wet deposition in the summer Indian subcontinent, Bangladesh, with inorganic arsenic dominating, accounting for ∼80% of total arsenic in this medium. Lower concentrations of both species were found in monsoonal wet deposition in the winter Indian subcontinent, Sri Lanka. The only other species present was dimethylarsinic acid (DMAA), but this was usually below limits of detection (LoD). We hypothesize that TMAO and inorganic arsenic in monsoonal wet deposition are predominantly of marine origin. For TMAO, the potential source is the atmospheric oxidation of marine derived trimethylarsine. For inorganic arsenic, our evidence suggests entrainment of water column inorganic arsenic into atmospheric particulates. These conclusions are based on weather trajectory analysis and on the strong correlations with known wet deposition marine derived elements: boron, iodine, and selenium. The finding that TMAO and inorganic arsenic are widely present and elevated in monsoonal wet deposition identifies major knowledge gaps that need to be addressed regarding the understanding of arsenic’s global cycle

Urinary Biomarkers KIM-1 and NGAL for Detection of Chronic Kidney Disease of Uncertain Etiology (CKDu) among Agricultural Communities in Sri Lanka.

Chronic Kidney Disease of uncertain etiology (CKDu) is an emerging epidemic among farming communities in rural Sri Lanka. Victims do not exhibit common causative factors, however, histopathological studies revealed that CKDu is a tubulointerstitial disease. Urine albumin or albumin-creatinine ratio is still being used as a traditional diagnostic tool to identify CKDu, but accuracy and prevalence data generated are questionable. Urinary biomarkers have been used in similar nephropathy and are widely recognised for their sensitivity, specificity and accuracy in determining CKDu and early renal injury. However, these biomarkers have never been used in diagnosing CKDu in Sri Lanka. Male farmers (n = 1734) were recruited from 4 regions in Sri Lanka i.e. Matara and Nuwara Eliya (farming locations with no CKDu prevalence) and two CKDu emerging locations from Hambantota District in Southern Sri Lanka; Angunakolapelessa (EL1) and Bandagiriya (EL2). Albuminuria (ACR ≥ 30mg/g); serum creatinine based estimation of glomerular filtration rate (eGFR); creatinine normalized urinary kidney injury molecule (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were measured. Fourteen new CKDu cases (18%) from EL1 and nine CKDu cases (9%) from EL2 were recognized for the first time from EL1, EL2 locations, which were previously considered as non-endemic of the disease and associated with persistent albuminuria (ACR ≥ 30mg/g Cr). No CKDu cases were identified in non-endemic study locations in Matara (CM) and Nuwara Eliya (CN). Analysis of urinary biomarkers showed urinary KIM-1 and NGAL were significantly higher in new CKDu cases in EL1 and EL2. However, we also reported significantly higher KIM-1 and NGAL in apparently healthy farmers in EL 1 and EL 2 with comparison to both control groups. These observations may indicate possible early renal damage in absence of persistent albuminuria and potential capabilities of urinary KIM-1 and NGAL in early detection of renal injury among farming communities in Southern Sri Lanka

sj-docx-1-cjk-10.1177_20543581231199013 – Supplemental material for Prevalence of Chronic Kidney Disease of Uncertain Etiology Within Selected Farming Communities in Rural Sri Lanka

Supplemental material, sj-docx-1-cjk-10.1177_20543581231199013 for Prevalence of Chronic Kidney Disease of Uncertain Etiology Within Selected Farming Communities in Rural Sri Lanka by E. M. D. V. Ekanayake, P. Mangala C. S. De Silva, T. D. K. S. C. Gunasekara, W. A. K. G. Thakshila, S. D. Gunarathna, R. A. I. Pinipa, Sudheera Jayasinghe, E. P. S. Chandana, E. S. Wijewickrama and Nishad Jayasundara in Canadian Journal of Kidney Health and Disease</p

Association of albumin to creatinine ratio (ACR, mg/g Cr) with urinary KIM-1 (5A), estimated glomerular filtration rate (eGFR) (ml/min/1.73 m²) with urinary KIM-1 (5B), albumin to creatinine ratio (ACR, mg/g Cr) with urinary neutrophil gelatinase-associated lipocalin (5C) and estimated glomerular filtration rate (eGFR) (ml/min/1.73 m²) with urinary NGAL (5D) in the CKDu emerging locations EL1 and EL2.

<p>Association of albumin to creatinine ratio (ACR, mg/g Cr) with urinary KIM-1 (5A), estimated glomerular filtration rate (eGFR) (ml/min/1.73 m²) with urinary KIM-1 (5B), albumin to creatinine ratio (ACR, mg/g Cr) with urinary neutrophil gelatinase-associated lipocalin (5C) and estimated glomerular filtration rate (eGFR) (ml/min/1.73 m²) with urinary NGAL (5D) in the CKDu emerging locations EL1 and EL2.</p