A pragmatic approach for assessing risk of arsenic in water–soil–plant-human continuum in an arsenic endemic area (Nadia) of West Bengal, India

Abstract A pragmatic approach has been chosen to assess the risk of arsenic (As) in the water-soil-plant-human continuum in an arsenic-prone area of Nadia district in West Bengal. Arsenic is a dangerous carcinogen, and people’s exposure to As via rice consumption is widely recognized. For this purpose, 201 paired soil and rice grain samples were collected from the main rice-producing agricultural field in West Bengal and analysed for their pH levels, organic carbon, extractable As, and As content in rice grain. Olsen extractable As concentration varied from 0.48 to 3.57 mg kg− 1 with a mean value of 1.45 mg kg− 1. Rice grain samples contained As in the 0.20 to 0.61 mg kg-1 range while the mean value was 0.43 mg kg− 1. The hazard quotient for As intake via human consumption is due to the rice grain varying between 0.27 to 0.83. Lifetime cancer risks related to As intake through drinking water and dermal intake were 1.0 × 10− 3 and 4.23× 10− 5, respectively, yielding a cumulative value for an overall lifetime cancer risk ranging from 5.70 × 10 − 4 to 4.10 × 10− 3 with a mean value of 1.09 × 10− 3. Solubility-free ion activity model (FIAM) could explain up to 75% variation in As concentration in rice grain. This model has been successfully validated in half of the data set for its future use for the first time. A ready reckoner was developed based on FIAM to define toxic limits of extractable As in soil with reference to pH, OC, and grain As content.