The researchers say that all 32 tests conducted so far had failed to prove that chemicals such as Cadmium Glyphosate or Arsenic were the main causes.

A comprehensive report compiled on this regard was handed over to President Maithripala Sirisena recently.

Speaking, project manager - chief engineer of the National Water Supply and Drainage Board - Dr. S. K. Weragoda has said that Cadmium or Arsenic cannot be considered as the main reasons when considering the amounts found in the main affected areas.

Meanwhile, a similar test in Japan had shown similar results, he added.