Conflicting reports highlight scientific data gaps in Sri Lanka’s chronic kidney disease
[COLOMBO] A WHO study that blames arsenic for rising levels of chronic kidney disease in Sri Lanka is in conflict with another study that points to poor quality drinking water, report Dilrukshi Handunnetti and Smriti Daniel.
CKD involves progressive kidney damage and loss of the organ's function of excreting waste products over three or more months. The absence of clinical symptoms until late stages makes diagnosis and treatment difficult.
Sri Lanka has reported a spurt in CKD cases since the 1990s with 80 percent of patients ending up with total kidney failure within two years of diagnosis. Treatment – dialysis or organ transplantation – being costly, death becomes inevitable for most victims.
The WHO study – commissioned by Sri Lanka's ministry of health and released to the media on 15 August – attributed CKD to arsenic in groundwater. It called for a robust regulatory framework “to improve the quality control of imported fertiliser(s), particularly with regard to nephro-toxic (kidney damaging) agents such as cadmium and arsenic.”
A day later, the New Delhi - based non-government organisation (NGO) Centre for Science and Environment (CSE) released a separate report on CKD, with conflicting conclusions.
Commissioned by Sri Lanka's ministry of water supply and drainage and a local NGO, Centre for Environmental Justice, the CSE study ruled out arsenic or heavy metals such as cadmium, lead and chromium in food and water as the cause of CKD, and pointed, instead, to poor water quality.
Tests by the CSE revealed dissolved solids, hardness, calcium and alkalinity exceeding desirable levels in water drawn from dug wells or tube wells and used unfiltered by people in affected areas.
The CSE findings were released in Anuradhapura in Sri Lanka's North-Central province which, along with the city of Polonnaruwa, has high CKD prevalence.
CSE's findings are yet to be peer-reviewed. Sri Lanka's minister for water supply and drainage has accepted them. "We are planning to launch mobile drinking water services and also establish rural water schemes with treatment of water," Dinesh Gunawardene told SciDev.Net.
The CSE found CKD cases to be typically of men in the 30–60 age group who were paddy farmers or agricultural labourers living in Sri Lanka’s dry zone. In recent years, however, the disease has spread into the North-Western, Eastern, Central, Northern and Uva provinces and has begun to claim women, children and even cattle as victims.
CSE's pollution monitoring laboratory analysed 35 water samples from key affected areas and compared them with non-affected areas. It also tested 16 soil samples, six rice plant and grain samples, five pesticide samples and three fertiliser samples for arsenic content.
While WHO placed the figure of those affected by CKD at 400,000 people, the CSE said the figure was closer to 15,000.
Chandra Bushan, deputy director-general at CSE, said the focus of research should now switch to the possible role of toxins and heavy metals from sources other than food and drinking water, particularly water with high content of calcium, fluorides and total dissolved solids.
Oliver Illeperuma, head of the department of chemistry at the Peradeniya University, told SciDev.Net that the divergent opinions expressed by the two teams underscored the need for better data gathering.
"Sound data gathering becomes possible with scientific capacity building. That will also lead to scientifically-sound decision-making on long- and short-term measures required to tackle the spread of the disease," Illeperuma said.
Priyani Paranagama, head of the chemistry department at Kelaniya University, said her team's independent research, which has not been peer-reviewed, has indicated traces of arsenic in the unnaturally dark soles and palms of patients.
Some autopsies of CKD victims, conducted by the health ministry over the past two years and whose reports were analysed by a WHO team, have established retention of arsenic in hair and nails, Paranagama told SciDev.Net.
Paranagama said the next phase of WHO research on behalf of the health ministry would focus on "how to clear the soil of arsenic residue."