Arsenic Contamination in Rice Grown Under Anaerobic Condition in Arid Agriculture: Assessment and Remediation

Arsenic (As) concentrations in fine (2) and coarse (3) rice varieties belonging to Hafizabad, Gujranwala and Sheikhupura districts was assessed initially by means of field survey, followed by pot experiments. Bulk soil samples collected from same rice districts (Hafizabad and Gujtanwala) were spiked with As (0, 10, 20 mg kg(-1)) and each was amended with iron sulphate (0, 25, 50 g kg(-1)) to investigate their effect on plant growth and uptake under anaerobic conditions. Survey results revealed that mainly fine long grain (Super Basmati and KSK 515) and coarse long grain (Basmati 386 and Kainat) rice varieties were grown in the area. Overall, 16% rice grain samples were above the recommended permissible limit (RPL) of 300 mg kg(-1). Among varieties, 24% grain samples of coarse and 12% of fine varieties had As concentration above the RPL. Results of pot experiments showed a significant decrease in straw and grain yield and increase in As concentration with increasing rates of As spiking. Paddy yield increased significantly when As spiked soils were amended with iron sulfate; and opposite was true for As concentration.