Significance of the prime factors regulating arsenic toxicity and associated health risk: a hypothesis-based investigation in a critically exposed population of West Bengal, India.

The suffering from arsenic toxicity is a long-standing concern in Asian countries. The role of the key factors (arsenic intake, age and sex) regulating arsenic toxicity is aimed to evaluate for a severely exposed population from Murshidabad district, West Bengal. Mean arsenic concentrations in drinking water supplied through tube well, Sajaldhara treatment plant and pipeline were observed as 208, 27 and 54 µg/l, respectively. Urinary arsenic concentration had been observed as < 3-42.1, < 3-56.2 and < 3-80 µg/l in children, teenagers and adults, respectively. Mean concentrations of hair and nail arsenic were found to be 0.84 and 2.38 mg/kg; 3.07 and 6.18 mg/kg; and 4.41 and 9.07 mg/kg, respectively, for the studied age-groups. Water arsenic was found to be associated with hair and nail (r = 0.57 and 0.60), higher than urine (r = 0.37). Arsenic deposition in biomarkers appeared to be dependent on age; however, it is independent of sex. Principal component analysis showed a direct relationship between dietary intake of arsenic and chronic biomarkers. Nail was proved as the most fitted biomarker of arsenic toxicity by Dunn's post hoc test. Monte Carlo sensitivity analysis and cluster analysis showed that the most significant factor regulating health risk is 'concentration of arsenic' than 'exposure duration', 'body weight' and 'intake rate'. The contribution of arsenic concentration towards calculated health risk was highest in teenagers (45.5-61.2%), followed by adults (47.8-49%) and children (21-27.6%). Regular and sufficient access to arsenic-safe drinking water is an immediate need for the affected population.

Different levels of arsenic exposure through cooked rice and its associated benefit-risk assessment from rural and urban populations of West Bengal, India: a probabilistic approach with sensitivity analysis.

Rice arsenic (As) contamination and its consumption poses a significant health threat to humans. The present study focuses on the contribution of arsenic, micronutrients, and associated benefit-risk assessment through cooked rice from rural (exposed and control) and urban (apparently control) populations. The mean decreased percentages of As from uncooked to cooked rice for exposed (Gaighata), apparently control (Kolkata), and control (Pingla) areas are 73.8, 78.5, and 61.3%, respectively. The margin of exposure through cooked rice (MoEcooked rice) < 1 signifies the existence of health risk for all the studied exposed and control age groups. The respective contributions of iAs (inorganic arsenic) in uncooked and cooked rice are nearly 96.6, 94.7, and 100% and 92.2, 90.2, and 94.2% from exposed, apparently control, and control areas. LCR analysis for the exposed, apparently control, and control populations (adult male: 2.1 × 10-3, 2.8 × 10-4, 4.7 × 10-4; adult female: 1.9 × 10-3, 2.1 × 10-4, 4.4 × 10-4; and children: 5.8 × 10-4, 4.9 × 10-5, 1.1 × 10-4) through cooked rice is higher than the recommended value, i.e., 1 × 10-6, respectively, whereas HQ > 1 has been observed for all age groups from the exposed area and adult male group from the control area. Adults and children from rural area showed that ingestion rate (IR) and concentration are the respective influencing factors towards cooked rice As, whereas IR is solely responsible for all age groups from urban area. A vital suggestion is to reduce the IR of cooked rice for control population to avoid the As-induced health risks. The average intake (µg/day) of micronutrients is in the order of Zn > Se for all the studied populations and Se intake is lower for the exposed population (53.9) compared to the apparently control (140) and control (208) populations. Benefit-risk assessment supported that the Se-rich values in cooked rice are effective in avoiding the toxic effect and potential risk from the associated metal (As).

Rice grain arsenic and nutritional content during post harvesting to cooking: A review on arsenic bioavailability and bioaccessibility in humans.

Rice (Oryza sativa L.) is considered as the staple food for 50% of the world's population. Humans are exposed to arsenic (As) through rice consumption, which is a global health issue that requires attention. The present review reflects the scenario of rice grown in As endemic regions of Asia that has a significant portion of inorganic As (iAs) compared to other rice grown areas around the world. Post-harvesting, pre-cooking, and cooking procedures in South and South-East Asian countries employ As-contaminated groundwater. Polishing of brown rice and parboiling, washing and cooking with As-safe water can reduce As concentration and nutrient level in cooked rice. However, in rural parts of South-east Asia, rice is usually cooked using As-contaminated groundwater and consumption of this As enriched rice and water may cause a significant health exposure in humans. Bioaccessibility and bioavailability of As can be determined using in-vitro and in-vivo techniques that can be utilized as a tool to assess As exposure in humans. Arsenic in cooked rice may be reduced by using newly developed cooking procedures such as Kateh cooking, steam percolating, and the parboiled and absorbed (PBA) method. For individuals living in rural regions, using rainwater or treated surface water for drinking and cooking is also an alternative. Although this study examined the processes involved in the post-harvesting, pre-cooking, and cooking stages, there are still significant research gaps in this area that must be addressed in near future.