Throw the baby away with the bathwater?


Local social media has been giving huge publicity to a recent San Francisco Federal court judgement in favour of a plaint filed by a groundskeeper, Dewayne Johnson in California claiming that his illness, non-Hodgkin lymphoma (NHL), a cancer, was caused by glyphosate. He had been regularly applying the weed killer, in school playgrounds. A government toxicologist, Dr Charles W. Jameson was a key witness for the prosecution. He gave evidence supporting Johnson and his testimony was that “To a reasonable degree of scientific certainly”, glyphosate and glyphosate-based herbicides are likely to cause cancer in humans, particularly at real-world exposures including the levels farm workers and others face when using the weed killer.

Interestingly, this toxicologist was a member of the team that declared in their report to the International Agency for Research on Cancer (IARC) in 2015 that glyphosate is” probably cancer causing” leading to placement of this chemical in Class 2 A of the carcinogenicity classification. However, there are apparently some 300 other studies that are contrary to the IARC finding, and refuting the contention that glyphosate is cancer causing. Chief among these are two studies, the Joint WHO and FAO Meeting on Pesticide Residues (JMPR) which categorically states that there is no evidence that glyphosate is either carcinogenic or genotoxic. Even more comprehensive is the American Health Study with some 90, 000 farmers using glyphosate over a period exceeding 25 years and published in November, 2017. It too concludes that there is no evidence that glyphosate is carcinogenic. In this background, therefore, the San Francisco Court judgement is difficult to comprehend.

Contradictory judgements

The San Francisco Chronicle August 13 argues that despite this verdict ‘courts will differ on Monsanto’s herbicide’ in regard to the numerous plaints filed against the company claiming damages by the herbicide applicators. Despite a judgement by a California court early this year, that Glyphosate products should carry a warning label consistent with the IARC pronouncement that it is ‘probably cancer causing’, it would appear that the verdict had been annulled. Subsequently, a federal judge in Sacramento has prohibited California State from requiring such a label. He had concluded that a “heavy weight of evidence” showed that the herbicide glyphosate was safe. In his judgement he had cited the report of the US Environmental Protection Agency and that of other regulatory bodies in Europe that the herbicide, glyphosate, was safe! Contradictory judgements therefore imply that there is no final proof that the herbicide is cancer causing or ‘probably cancer causing’ as determined by IARC.

Moreover, causation in epidemiology is a highly complex subject, and mere association does not necessarily imply causation. In other words, Dewayne Johnson’s association with glyphosate does not necessarily mean that the latter caused him NHL. In epidemiology, there are eight universally accepted criteria known as the Bradford-Hill criteria at least several of which should be satisfied for establishing causation, only one of them being the strength of the association. It would appear that the jury’s decision was substantially conditioned by the terminal illness of Johnson with his body, virtually totally covered in lesions and welts! Probably an element of sympathy influenced the decision. Further, the question should be asked whether a jury of ordinary layman without expert knowledge in the subject could make a decision on a matter of this nature. We, however, have no information on the competence of the jurors on the subject. Monsanto is expected to appeal against the judgement. Let us wait for the outcome.

Meanwhile this news has caused, as to be expected, much euphoria among the anti-glyphosate lobbyists both here and overseas. One of our chief lobbyists is a Buddhist monk, who has no notion of science or agriculture, but has been vehemently opposing conventional agriculture, agrochemical use and actively promoting organic farming in the course of which he has promoted a fertilizer concoction, “Pivithuru Pohora” of which he is also the chief architect. This fertilizer has failed to show any response in the Agriculture Department’s trials, but has been vigorously promoted among Mahaweli System B farmers, some of who have been paid compensation by the Mahaweli Authority for loss of crop consequent on its use! On enquiry, one farmer told the writer that he was paid Rs 12,500 as compensation last season .The other is a pharmacologist who has been shouting hoax that glyphosate is responsible for the kidney disease, CKDu, and even had come up with a hypothesis that glyphosate complexing with metallic elements in the hard water in the NCP is probably the cause of the disease.

This hypothesis has not been supported by any other researcher and has been severely criticized by several reputed chemists in the country that it is utterly faulty! He, together with the monk, has also been insisting that the government should not lift the ban on the weed killer.

He even clamoured over the TV following the San Francisco judgement, that he too is filing litigation against Monsanto for ‘glyphosate causing’ CKDu! The writer has gone this far on these highly biased personalities to give an indication of the magnitude of damage that they cause to poor farmers and the misinformation spread in the public mind. The ban on the herbicide was, however, lifted recently at least for two crops tea and rubber thanks to the valiant efforts of the Minister of Plantation industries. Ideally it should have been lifted for all crops because it was banned on the false premise that it caused the kidney disease.

Many main stream scientists and the Pesticide Technical Advisory Committee have requested the government to do so. Despite the ban illegal glyphosate is being used across the country virtually on every crop at great cost to the farmer as it is exorbitantly expensive. The farmers using it at any cost are indicative of their dependency on it to control weeds. The government should do well to lift the ban for all crops. There is now convincing evidence that CKDu is associated with the source of potable water and not any agrochemical.

Adequate precautions

In conclusion, glyphosate is the most widely used pesticide both globally and locally. The quantity used is more than that of the cumulative total of all other pesticides! In comparison to most other pesticides its toxicity is relatively low, its acute reference dose (ARfD) is as high as 0.5 mg/kg of body weight, and the acceptable operator level (AOEL) is set at 0.1 mg /kg body weight per day. Despite such low toxicity indicators, given, the emerging evidence of possible risks, the government should have wide farmer and public training on its safe use.

Our farmers often spray pesticides bare bodied for want of strict advice and rules. It would appear that Johnson, the California groundskeeper has been very frequently spraying the weed killer. By contrast in arable crops here it is usually applied once per season prior to planting. In tea, however, the regular applicators apply more frequently, and their exposure probably higher. On the other hand vegetable farmers apply insecticides of much higher toxicity such as carbosulphan, propanophos and diazinon many times per season which could be more risky than glyphosate. Further, given our magnitude of exposure to other toxins such as vehicle exhaust fumes and emissions from the coal power plants many of which are Class 1 carcinogens, the risk of glyphosate should be negligible providing adequate precautions are taken. The Johnson fiasco should be an eye opener to the authorities for vigilant training of farmers in pesticide use as also for enacting rigid rules and regulations.

Given the vital need of glyphosate in weed management in farming and the fact that no other country has banned it despite emerging concerns, we hope the government will not rush again into ‘throwing the baby away with the bath water’ The health authorities should, as a precautionary measure, undertake a study on the status of glyphosate residues in farmers who spray it regularly, especially of the tea estate applicators. 

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