Assessment of arsenic exposure through dietary sources and drinking water in Gallbladder cancer patients of Bihar

• Gallbladder cancer risk linked to dietary arsenic exposure in Bihar, India. • Rice and wheat showed elevated arsenic levels exceeding FAO safety limits. • 21 % of handpump water samples exceeded WHO arsenic guideline (10 µg/L). • 39 % of patients had non-cancer risk (HQ) and 59.6 % had cancer risk (CR) through rice. • Urgent need for safe irrigation, biomonitoring, and dietary diversification. In the recent times, there has been significant rise in the Gallbladder cancer (GBC) incidences globally. The present study examines the relationship between dietary arsenic exposure and GBC risk in n=141 inhabitants of Bihar. A total of n=705 samples were collected from n=141 subject’s households which included rice, wheat, pulse, potato and their household water samples. The study revealed that 11% of rice samples, 2% of potato samples, 6% of pulse samples, and 33% of wheat samples exceeded FAO permissible limits (200 µg/kg for rice, potatoes, and pulses; 100 µg/kg for wheat), with maximum concentrations of 574.8 µg/kg, 912 µg/kg, 267.2 µg/kg, and 376.4 µg/kg, respectively. Additionally, 21% of 141 handpump water samples had arsenic concentration more than the WHO limit of 10 µg/L, with maximum concentration as 91.6 µg/L. Health risk assessments indicated significant non-carcinogenic (Hazard Quotient > 1) and carcinogenic (Cancer Risk > 1 × 10⁻⁶) risks, with rice emerging as the primary dietary contributor, followed by wheat, while pulses and potatoes posed lower risks. Pearson correlation coefficients (r = 0.2590–0.4446, p < 0.01) among staple food consumptions. In the present study, the human health risk assessment based on food samples showed that 17.73% of wheat samples exceeded the non-carcinogenic risk limit, and 58.15% exceeded the carcinogenic risk limit. Similarly, for rice samples, 39% of the exposed population showed potential non-carcinogenic risk, while 59.57% were at risk of carcinogenic effects. Rice showed the highest non-carcinogenic (HQ) and carcinogenic (CR) risks, with HQ values frequently exceeding the threshold of 1 and CR values surpassing the acceptable safety limit (1 × 10⁻⁶). This establishes rice as the primary dietary contributor to arsenic-related gallbladder cancer risk in the study population. Wheat presented moderate risk, with some HQ values exceeding 1 and CR values approaching the risk boundary, suggesting a secondary but significant contribution. In contrast, pulses demonstrated very low HQ and CR values, both well within safe limits, indicating negligible health risk from arsenic exposure through this food group. Overall, these findings highlight rice as the dominant dietary source of arsenic exposure among gallbladder cancer patients, followed by wheat, while pulses and potatoes pose comparatively lower risks. The study emphasizes the need for continuous biomonitoring and public health interventions, including safe irrigation and dietary diversification, to mitigate GBC risk in this arsenic-endemic region, with further research required to understand the impact of other confounding risk factors.