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

Abstract

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 microg/kg body weight per week. The mean urinary cadmium in patients diagnosed with stage 5 kidney failure was 7.6 microg/g creatinine and 11.6 microg/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.

Novel urinary biomarkers and their association with urinary heavy metals in chronic kidney disease of unknown aetiology in Sri Lanka: a pilot study

“…Several authors have suggested that exposure to Cd and As through agrochemicals are likely risk factors of CKDu [11,12,22]. In the present study, we used urinary Cd as an indicator of chronic exposure to, and the total body burden of, cadmium.…”

“…Several investigators have explored the aetiological contribution of exposure to various environmental toxins such as pesticides, microbial toxins and heavy metals [6,[8][9][10]. The role of chronic exposure to cadmium (Cd) and arsenic (As) through environmental contamination of agrochemicals remains a highly debated topic among scientists [6,[11][12]. The evidence regarding exposure to heavy metals as measured by levels of urinary excretion in patients and in controls and environmental samples is inconsistent [6,[11][12][13].…”

“…The role of chronic exposure to cadmium (Cd) and arsenic (As) through environmental contamination of agrochemicals remains a highly debated topic among scientists [6,[11][12]. The evidence regarding exposure to heavy metals as measured by levels of urinary excretion in patients and in controls and environmental samples is inconsistent [6,[11][12][13].Novel urinary biomarkers and their association with urinary heavy metals in chronic kidney disease of unknown aetiology in Sri Lank: a pilot study …”

The Prevalence of Obesity among Subjects with Chronic Kidney Disease – Cross Sectional Study of Sri Lanka Population

“…In the past decade a number of small scale studies were conducted to determine the aetiology, prevalence and complications of CKDu in North Central region [5,[7][8][9][10][11]. These hospital-based studies did not provide an accurate estimate of the problem as merely 10% or less of the people with CKD are aware of their diagnosis even in developed countries with better access to medical care [12].…”

“…Multiple aetiological factors have been postulated for CKDu including chronic exposure to Cadmium, Lead, Arsenic and Ochratoxin-A through food chain [8,9,[13][14][15][16]. However, increasing CKDu may be multifactorial and obesity may also be a contributing factor -that has not been systematically studied to date [17].…”