Abstract

Arsenic contamination of agricultural soils has emerged as an important environmental and public health challenge because of its adverse effects on crop quality and food safety. Rice (Oryza sativa L.) is particularly susceptible to arsenic accumulation due to its cultivation under flooded conditions. This study evaluated arsenic concentration, mineral composition and antioxidant biomarkers in rice cultivated in two irrigation farming communities (Fadamar Butuku and Fadamar Gabas) in Bodinga Local Government Area, Sokoto State, Nigeria. Rice, soil and irrigation water samples were collected and analyzed using standard analytical procedures. Arsenic and mineral elements (Ca, Fe, Mg and Zn) were determined using Atomic Absorption Spectrophotometry following acid digestion, whereas catalase (CAT), superoxide dismutase (SOD) and reduced glutathione (GSH) were determined using established biochemical methods. Data were expressed as mean ± standard deviation and compared using Student's t-test at p < 0.05. Calcium was the predominant mineral in both rice samples (43.31 ± 1.09–43.69 ± 1.63 mg/kg). Iron and magnesium concentrations were significantly higher in rice from Fadamar Gabas, whereas zinc was slightly higher in Fadamar Butuku. Catalase activity and glutathione concentration were higher in Fadamar Butuku, while SOD activity was greater in Fadamar Gabas, suggesting efficient antioxidant defense against oxidative stress. Arsenic concentrations in rice (0.018–0.020 ppm), soil (0.027–0.030 ppm) and irrigation water (0.0108–0.012 ppm) were generally below internationally accepted safety limits for agricultural exposure, although irrigation water slightly exceeded the WHO guideline for drinking water. The study demonstrates that rice cultivated in the study area possesses acceptable nutritional quality with low arsenic contamination. Continuous environmental monitoring remains necessary to prevent future accumulation and ensure food safety.

Key words: Rice, Arsenic, Antioxidant biomarkers, Mineral composition, Oxidative stress, Food safety.