Easy access to agro-chemicals in Sri Lanka blamed for public health scare
A revolution gone awry
In the early 1990s, hospitals in Sri Lanka’s North Central Province, the main agricultural region of the country, started reporting an unusually high incidence of chronic renal failure. About 5,000 persons reported ill in 1993. By 2009, the disease assumed epidemic proportions. That year over 9,000 patients from North Central and its neighbouring Uva and North Western provinces were under treatment in Anuradhapura Hospital alone. The disease, which often requires kidney transplant in its last stage, has since been a leading cause of deaths in the region.
What made doctors sit up and take notice was these patients did not have hypertension or type-II diabetes, as is usual in renal failure cases. About 90 per cent of the patients were paddy farmers. One credible explanation has been offered by J M R Sarath Bandara, who teaches agricultural biology at University of Peradeniya in Kandy in Central Province. What Bandara found in his studies on the epidemic of chronic renal failure, published in several peerreviewed journals, offers an indictment of the Green Revolution in Sri Lanka.
In 2002, while studying the toxicity of algae, Bandara’s team stumbled upon high cadmium levels in soil samples collected from North Central Province. This was puzzling as there are no zinc mines in the region that release cadmium, nor does the uncultivated soil contain high trace levels of this toxic heavy metal that can accumulate in the kidney and cause renal failure. The source of contamination could not be groundwater as farmers there depend on reservoirs for irrigation and potable water.
The team looked at food habits of communities—rice, freshwater fish and lotus stem, with less fibre and fewer greens. All the food items had high cadmium levels. The survey also found that women ate less and reserved the fish portions for the men, which perhaps accounted for the fewer incidence of renal failure among women.
Suspicion then turned to high fertiliser use in the paddy and vegetable farms. Tests confirmed high levels of cadmium—23 to 71.7 mg per kg of fertiliser— in low-grade imported triple superphosphate, a commonly used fertiliser. Natural fertilisers like Eppawala rock phosphate have cadmium levels of 15 mg/kg. The team took a closer look at the catchments of 21 tributaries of the river Mahaweli that flows through the province. An integral component of Sri Lanka’s Green Revolution, the Mahaweli Ganga Development Programme on the Mahaweli and six allied river basins is the country’s largest rural development initiative with irrigation, flood control, hydropower and resettlement of landless poor as its goals.
Work on this mega project started in 1970, was accelerated in 1979, and involved diverting Sri Lanka’s biggest river for irrigating 140,000 hectares in North Central Province. This area has about 4,000 small water reservoirs that are fed by the diverted waters of the Mahaweli and from the catchments of its tributaries. These are interconnected with channels and cascades that drain water from the rice and vegetable fields, and are an important irrigation and drinking water source for rural communities.
The organic-rich, acidic soils in the upper Mahaweli catchments, together with 5,300 mm rainfall with 65 per cent runoff, create ideal conditions for cadmium to leach from agricultural fields to contaminate these reservoirs.
Water and sediment samples from reservoirs showed high levels of cadmium, 0.03 to 0.06 mg/l, which are 10-20 times more than the maximum contamination level of 0.003 mg/l set for drinking water by the World Health Organization (WHO).
Using GIS mapping, the team also considered the type and amount of fertiliser used in each cropping system, and found unacceptably high cadmium “loading” in paddy fields (26,479 grammes/hectare/year) and vegetable farms (628,701 g/ha/year). The cadmium load was lower (23,987 g/ha/year) in tea growing areas, as agro-chemicals are used judiciously in export-dominated tea plantations. Bandara estimates about 69 tonnes of cadmium has accumulated in the reservoirs and catchments in his study area in North Central Province since 1973.
Meanwhile, the epidemic is shifting to lower age groups. While fifth-stage chronic renal failure, which requires dialysis or a transplant, was common among 40-60-year-olds in 2002, recent studies by Bandara found patients in the age group of 25-35, with some as young as 15 years of age.
To be sure, there are competing theories about the cause of the high prevalence of the disease in the region—it has been linked to the use of cheap aluminium cooking vessels, toxic blue-green algae in reservoirs, arsenic, mercury, pesticides and even uranium contamination in soil. The country’s atomic energy authority and the ministry of healthcare and nutrition are conducting independent investigations to ascertain the cause. WHO is convening a nationallevel workshop in June that will bring together doctors, ministry officials and researchers to discuss the state of research on this public health epidemic.
Incidence of contamination of food chain by heavy use of agro-chemicals and resulting diseases in other parts of the country are as unsettling. In 2000, seven of 12 drinking water schemes in Kalpitiya peninsula in Colombo, funded by the Asian Development Bank, had to shut due to high nitrates found in the shallow aquifers. Likewise, a study using GIS mapping by non-profit Neo Synthesis Research Centre, commissioned by the water supply and drainage department to investigate an outbreak of 1,800 cases of Hepatitis A around Kandy, found high levels of nitrates in 15 per cent of the 790 points mapped in Paradeke Oya watershed in Gampola, an area known for high agro-chemical use.
There is evidence, albeit unpublished, of high agro-chemical use in Uva and North Western provinces, a hilly region home to much of Sri Lanka’s famed tea gardens. “Close to 1,200 streams start in Uva’s Badulla district alone, all inside tea plantations under private management,” says Prabath Kumara, director of Future in Our Hands (FIOH), a non-profit that pushes organic farming. Although exportdependent tea gardens carefully regulate agro-chemicals, many suspect that plantation workers use copious amounts of chemical fertilisers and pesticides in their vegetable farms inside tea estates, he said. Run-off from these vegetable patches contaminates streams and reservoirs downstream.
“Fertiliser is the Trojan horse of Sri Lanka’s Green Revolution,” says Bandara. Its consumption doubled from 32,000 tonnes in 1971 to 74,000 tonnes in 1975, when high-yielding, fertiliserresponsive rice varieties were introduced as part of the programme. Since then, fertiliser use has increased at 3.5 per cent per annum, he said. The country imports almost all the fertiliser it needs, about 650,000 tonnes a year, including urea, triple superphosphate and muriate of potash. About 81.5 per cent of fertiliser is imported from China; the rest from Turkey and Egypt.
In 2005, a political slogan became policy when the government announced the ambitious Mahinda Chinthana (President Mahinda Rajapaksa’s vision), which pushed development across all sectors of the economy. In agriculture this meant raising productivity by providing fertiliser at a tenth of its commercial cost—350 Sri Lankan Rupees (LKR; 1 LKR=Rs 0.4) per 50 kg bag, with a maximum of three bags per acre (0.4 ha) of paddy. Fertiliser subsidies bleed the exchequer. In December 2010, the fertiliser import bill increased 119.4 per cent, for which the government paid a bruising LKR 30 billion. Tracts of land are being brought under cultivation in the north and east provinces following the end of hostilities. The government recently announced a partial subsidy for coconut farmers. The new Divi Neguma scheme to promote vegetable home gardens will hand out hybrid seeds and subsidised fertiliser packets to one million households in the country.
Despite this cost that will be absorbed by the treasury, the National Fertilizer Secretariat says there is still a shortfall of 272,000 tonnes of fertiliser to meet the demand (see table).
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