Chronic renal failure in Sri Lanka caused by elevated dietary cadmium: Trojan horse of the green revolution

The endemic of chronic renal failure (CRF) emerged in 2002 in the farming provinces of Sri Lanka. An estimate of dietary cadmium intake was between 15 and 28 μg/kg body weight per week. The mean urinary cadmium in patients diagnosed with stage 5 kidney failure was 7.6 μg/g creatinine and 11.6 μg/g for asymptomatic persons. The agrochemical triple superphosphate (TSP) fertilizer containing 23.5–71.7 mg Cd/kg was the source of cadmium added to soils. Mean Cd content in cultivated vs. uncultivated soils in Anuradhapura district was 0.02 ± 0.01 vs. 0.11 ± 0.19 mg/kg while in Polonnaruwa district, it was 0.005 ± 0.004 vs. 0.016 ± 0.005 mg/kg. Prior to the Green Revolution, the amount of fertilizer used in rice cultivation in 1970 was 32,000 metric tons (Mts) rising to 74,000 Mts in 1975. Up to 68.9 Mts of Cd could have entered into the rice-cascade reservoir environment from TSP use since 1973. Diversion of the Mahaweli River in 1970–1980 further increased cadmium input. Cadmium transfer from Upper Mahaweli water to Polgolla was 72.13 kg/day. Cadmium content of the sediments from reservoirs collecting cadmium from irrigated TSP fertilized crop fields (rice and vegetables) was 1.8–2.4 mg/kg.