Impact of soil-type, soil-pH, and soil-metal(loids) on grain-As and Cd accumulation in Malawian rice grown in three regions of Malawi

Abstract Impact of soil type, soil-metal(loids) and soil-pH of rice paddies on grain-arsenic (As) and cadmium (Cd) accumulation in Malawian rice was investigated to explore the extent to which Malawi's geographical location, soil types, soil-metal(loids) and soil-pH and their interactions impact on grain-As and Cd accumulation. Multivariate techniques were used to evaluate the relationships among measured parameters. Results showed that the 1st three principal components consisting of soil-types, soil-metal(loids) and soil-pH explained 83% of total variance of both grain-As and Cd accumulation. For As, highest grain-As was detected in rice from central region (CR) cultivated in vertisols characterized with soil-As ≥ 2.5 mg/kg and soil-pH > 7.0 whereas the lowest was in rice from northern region (NR) cultivated in fluvisols characterized with soil-[As] ≤ 1.5 mg As/kg soil and soil-pH range of 6.00 - 6.99. For Cd, highest grain-Cd was detected in rice from CR cultivated in luvisols with soil-As range of 2.0 - 3.0 mg/kg and soil-pH