SAFETY OF GLYPHOSATE AS A WEEDICIDE
I would like to enlighten the Sri Lankan public and the policymakers alike about a myth and a dark cloud that shrouded over our agricultural sector costing millions of rupees and loss of agricultural productivity as a result of banning the use of Glyphosate, which was the time tested and cost effective weedicide that protected our major crops from the time immemorial. Since the banning of the use of Glyphosate as a weedicide, farmers refrained from weeding due to high labour cost and as a result, nutrients sparingly added to crop farms at a very high cost were absorbed by the weeds thereby declining the yields of almost all crops.
My thanks and appreciation to Prof. Deepal Mathew of the Biochemistry Dept. of the Faculty of Medicine, University of Colombo for a well written, research-based article that appeared in the Daily News of August 1, 2017 disproving in no uncertain terms that the myth people had about toxic effect of Glyphosate hitherto believed to be the cause for high incidence of chronic kidney failure among the farmers in the North-Central and Eastern provinces. In agri-based developed nations like New Zealand and Malaysia where they use over ten times Glyphosate per unit area, has so far not observed a single case of kidney failure (CKDu) like in the North Central province of Sri Lanka.
Founder of the science of pharmacology uttered some 500 years ago that all substances are poisonous if consumed over the lethal dosage and to indicate the lethal dosage the unit used commonly is LD 50. If the LD 50 of a substance is below 25 it is extremely poisonous. If LD 50 is between 25 and 50, it is very dangerous. Higher the LD 50 value, the substance is safer health-wise. In his article, Prof Mathew has shown that common salt sodium chloride has an LD 50 value of 3000; while the same for Glyphosate is 5000. That means the mammalian toxicity of common salt is more than that of Glyphosate.
This whole issue started with a baseless publication of a report by a Researcher without any research background on agriculture, alleging that residual Glyphosate molecules leach into the water table through tanks and streams are the cause for the report of CKDu in the province which prompted policy makers to impose the ban. Sadly what this researcher did not know is that electrostatic attraction of the phosphate ion in Glyphosate bonds firmly with the soil preventing leaching of it to water streams.
It was way back in 2015 that this unsubstantiated publication culminated with a political issue, then compelling the government to impose a total ban on its import.
The agro-economists are at a loss as to the impact the import ban had on the productivity and yield of major crops like paddy, tea, rubber and coconut with the eventual loss of revenue running into millions.
While saluting Prof. Mathew for his well-written article, I strongly believe that it will be a good eye opener to policymakers to think about imminently lifting the ban, well of course after consulting eminent and independent crop research institutions, who have ample experience in field research on the use of Glyphosate to protect the agriculture of Sri Lanka.
Dr L M K Tillekeratne
Former Director RRI
Add new comment