Arsenic in water placing ‘whole nation at risk’ says scientist


By Lynn Ockersz

While there is a relation between arsenic in water and the high prevalence of a Chronic Kidney Disease of Unknown Etiology (CKDu) in some parts of Sri Lanka’s Dry Zone, the spread of ailments associated with arsenic poisoning, such as, cancers, ischaemic heart diseases, cerebro vascular diseases and diabetes mellitus, could mean that such poisoning is placing "the whole nation at a risk", a groundwater resources management symposium was told on Tuesday.

"The use of pesticides has already been identified as a risk factor for CKDu and we have continued with investigating pesticides as a cause of arsenic poisoning, Dr. Channa Jayasumana of the Department of Pharmacology of the Faculty of Medicine, Rajarata University, said in the course of a presentation at the seminar titled ‘Challenges in Groundwater Resources Management in Sri Lanka’, held at the Waters Edge hotel, Battaramulla.

The symposium was organized by the Ministry of Irrigation and Water Management, the Dam Safety and Water Resources Planning Project and the Water Resources Board.

"Certain types of soil, such as those with a high calcium content, have more arsenic retention ability and previous research has shown that our Dry Zone rice field soils are characterized by a high content of calcium compared to those of the Wet Zone. Previous research had also identified comparatively high amounts of arsenic in rice collected from CKDu endemic regions, such as Giradurukotte and Nikawewa, but had not correlated the findings with the prevalence of kidney disease. However, our analyses have revealed high amounts of arsenic in rice, that is, 100-500 ug/kg, which are compatible with the arsenic content in rice in West Bengal and Bangladesh. Besides, in our investigations of the hair samples of CDKu patients, a high arsenic content of 3.04-7.18 mg/kg was observed", Jayasumana pointed out.

He explained that a high arsenic and mercury content was detected in almost all the drinking water samples which were collected from the Dry Zone areas hit by CKDu. ‘The WHO standards for arsenic and mercury for drinking water are 10ug/l and 1ug/l, but in most of the water samples from our kidney disease affected areas, the readings were, arsenic 100-200 ug/l and 10-25 ug/l for mercury. The presence of arsenic was determined in samples of rice collected from the affected areas, in the urine and blood of patients, hair samples of CKDU patients, body parts of deceased patients, in water samples from paddy fields and in the soil, he said.

Commenting on the geographical distribution of CKDu patients, Jayasumana said that these areas overlap with the distribution pattern of high ground ‘water hardness’ in this country. Calcium is prevelant in ‘hard water’, which is a feature of our Dry Zone areas. Arsenic forms strong bonds with calcium and is difficult to elicit in ‘hard water’.

The areas worst hit by CKDu were, Girandurukotte 2500 patients, Medawachchiya 2000, Padaviya 1400 and Medirigiriya 600. In some of these areas, hyper-pigmentation and keratosis in the palms and soles of patients were observed.

The research team that investigates the causes, treatment and prevention methods for CKDu, is headed by Prof. Nalin de Silva, Dean, Faculty of Science, University of Keleniya. picHyper-pigmentation and keratosis observed in soles

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