The Endosulfan ban and the scientific debate that didn't happen

This post also appeared on Spicy IP

Kerala’s Endosulfan Ban---The science that never got discussed

While researching my article in Open Magazine on ‘Kerala’s endosulfan tragedy---Did it really happen?’, I came across several controversial points of view among the scientists I interviewed. These views have never really been debated in India, and probably never will, given the politicization of the events in Kerala. But in an ideal situation, they should have.

Increasingly (not just in India, but the world over), there is a tendency to conflate several issues surrounding a subject. In the case of GM foods, environmentalists conflate health effects, farmer suicides, super-weeds, contamination by transgenes, and Monsanto’s monopolistic practices, in their argument against GM foods. But these are five distinct issues, with five different sets of arguments. Here is an excellent article in Nature that separately addresses three controversial GM-related subjects and summarizes the state of evidence in each of them.

Similarly, in the case of the endosulfan ban, there were two separate questions---a) Were the diseases in Kerala caused by endosulfan? b) If they weren’t, should India have banned endosulfan, invoking the precautionary principle?

My story, which can be accessed here, argued that there was no credible epidemiological evidence that the diseases in Kasargod were caused by the aerial spraying of endosulfan.

But I did not address the other part of the debate. Should India have banned endosulfan?  

My research made me realize how divided scientists are on this issue. Interestingly, the differences are mostly about the policy decision to ban endosulfan, and not about the scientific ‘facts’ this decision was based on. There was broad consensus on the properties of endosulfan. And one thing I can say for sure is that contrary to what environmentalists claim with so much confidence, it is not a ‘well-known fact’ that endosulfan is bio-accumulative and harmful to humans.  

To understand the ‘facts’ of the issue, one needs to understand the criteria the Stockholm Convention uses to label a chemical as a persistent organic pollutant or POP. A POP is defined as a chemical that has four properties. First, it is persistent in the environment and does not degrade for long periods of time. The Stockholm Convention says chemicals with a half-life of more than 6 months in soil are POPs.  Second, the chemical should be capable of accumulating in living creatures---i.e, the rate at which an organism absorbs it should be greater than the rate at which it excretes it. Third, the chemical should be capable of long-range transport. And last, the chemical should impact human health adversely.

Let’s begin with persistence.

According to Ivan Kennedy, a professor of environmental chemistry from the University of Sydney with  numerous published papers on the behavior of endosulfan,  the data cited by the Stockholm Convention’s POP review committee to prove that endosulfan has a half-life greater than 6 months was either laboratory data or data from arctic regions. Both tend to be extreme values. Average values should have been used, considering that in warm, tropical climates, where 95% of the world’s endosulfan usage occurred till recently, endosulfan’s half-life in soil is much lower than six months.

In a document titled “Invalid basis for listing endosulfan as a POP: A critique with strong evidence that the Stockholm Convention is exceeding its mandate, ” Kennedy systematically questions the relevance of each bit of data cited by the Stockholm Convention’s POP Review Committee as evidence that endosulfan is a POP. He says these data and papers were cherry picked and did not reflect field conditions in tropical climates. Further, the process of listing endosulfan as a POP did not include peer-review, and therefore, could easily have been hijacked by political motivations.

I reached out to three of the scientists whose papers Kennedy said were cherry picked. In essence, Kennedy said that while the studies by these scientists were of good quality, they do not show that endosufan is persistent in the field, because they are lab studies. The scientists I contacted were N Sethunathan (author of ‘Persistence of Endosulfan and Endosulfan Sulfate in Soil as Affected by Moisture Regime and Organic Matter Addition’, Bulletin Environmental Contamination and Toxicology, 2002 ), Volker Laabs (author of ‘Fate of Pesticides in Tropical Soils of Brazil under Field Conditions’, J. Environ. Qual, 2002), and N Vasudevan (author of ‘Effect of Tween 80 added to soil on the degradation of endosulfan by Pseudomonas aeruginosa’, International Journal of Environmental Science and Technology, 2007).

Their responses were fascinating.

N Sethunathan believes endosulfan is persistent. But he agrees that his study was a lab study, as Kennedy alleges, and not a field study.

N Vasudevan said his study did not measure ‘persistence’ and half-life at all. They were only measuring prevalence of the pesticide and distribution in soil.

Volker Laabs agreed that his study was a lab study, but believes it is still relevant to the Convention’s decision. But he also agreed that endosulfan is unlikely to be persistent in tropical climates such as India.

All in all, I’d say Kennedy’s arguments bear out.

Next, I spoke to another UK-based environmental chemist, Crispin Halsall, of the Lancaster Environment Centre. His 2010 paper “Endosulfan, a global pesticide: A review of its fate in the environment and occurrence in the Arctic” in the journal Science of the Total Environment is also cited by the POP Review Committee. Further, Halsall advised the Committee and believes the decision to classify endosulfan as a POP was correct.

When I ran Kennedy’s arguments past him, however, Halsall seemed to agree with them broadly. He agreed that endosulfan is not persistent or bioaccumulative in tropical climates, but argued that even POPs like DDT behaved differently in different climates. However, he agreed that evidence of harm to human beings was not conclusive.

But his main point really was that even if there is inconclusive evidence about the health effects of endosulfan, it is enough to invoke the precautionary principle. According to him, classifying chemicals such as DDT as POPs was easy, because they were such obvious POPs. But with chemicals such as endosulfan, the evidence is weaker. Increasingly in the future, he feels, there will be more debate as chemicals such as endosulfan, which are ‘on the cusp’, come up for inclusion among POPs.

The first twelve chemicals to be classified as POPs by the convention were known as the Dirty Dozen. These included DDT, chlordane and dieldrin. These are “true POPs”---chemicals whose properties make them very obviously toxic. These chemicals easily meet the Stockholm Convention’s criteria. This means their half lives in soil are clearly higher than six months; they are clearly bioaccumulative; they travel long ranges; and they clearly effect human health.

But endosulfan is on the cusp. It may have some properties similar to true POPs, but in other ways, it behaves very differently.

Given all this, Keith Solomon, a professor of environmental science at Canada’s University of Guelph, feels the precautionary principle is just being used as a political tool in the endosulfan case. In a paper published this year in the Journal of Agricultural and Food Chemistry, Solomon authored a section on endosulfan, broadly making the same points Kennedy did in his criticism of the Convention’s decision. Solomon believes the use of precautions is enough, given the evidence on endosulfan, and that classification as a POP was an overkill.

What makes this debate more interesting is that Solomon is a co-author of the Science of the Total Environment paper, together with Crispin Halsall. Basically, two co-authors of the same paper disagree on the subject they are summarizing.

Given this background, let’s cut back to India.  First, why does India need endosulfan?

I quote from my story in Mint in 2011. “India is the supplier of 70% of the world’s endosulfan needs—a market valued at $300 million (Rs 1,340 crore). Out of the 9,000 tonnes India produces every year, half is bought by the country’s 75 million farmers, making it the world’s largest consumer of endosulfan. Much of it is used by farmers with small and marginal holdings, because endosulfan is cheap—Rs 286 per kg—and has a broad spectrum of effects. Alternatives such as flubendiamine and imidacloprid cost Rs 13,800 and Rs 2,229 per kg, respectively. Endosulfan is sprayed on all major crops such as vegetables, cotton, pulses and rice to combat pests such as whitefly, leafhoppers, aphids and cabbage worms, without harming insects such as bees, which help in pollination. “This is one of the safest insecticides for pollinators,” said A.K. Chakravarthy, entomology department head at Bangalore’s University of Agricultural Sciences (UAS).”

So, clearly, banning endosulfan would have a very significant impact on farmers’ livelihoods.

Let me add that being friendly to pollinators such as bees is no small deal.  Among the alternatives to endosulfan that were proposed by the Stockholm Convention, Imidacloripid is already being implicated in bee colony collapse disorder. Also, endosulfan has been used for so many years that there is enough data on how to use it safely. The same cannot be said about newer pesticides such as Flubendiamide. All pesticides, by nature, are toxic. Should we, then, prefer a pesticide that we have more data about, or switch to a newer, less-tested one, driven by fear?

Another alternative to endosulfan that the Stockholm Convention suggested was organic farming. I tried very hard to determine the impacts of organic farming in Kasargod after the ban on pesticides. C Jayakumar, an environmentalist with Thanal, an NGO which was a major campaigner against endosulfan, told me in an email that organic farming was working out fantastic for Kasargod.

But, as always, there was another side to the story.  

K M Sreekumar, the entomologist I quoted in my article, gave me the example of a rice farmer whose 400 acre crop was destroyed by an attack of leafhoppers, because endosulfan had been banned, and no suitable organic alternative was available yet.

Unfortunately, the Plantation Corporation of Kerala does not release data on cashew yields. So there is no way of knowing if overall yield in its cashew estates was affected due to abrupt shift to organic farming. But when I spoke to the managing director of PCK, he agreed that there had been an initial loss of productivity due to the increased attack of tea-mosquito bugs.

This is to be expected. Any shift to organic farming takes time, because a farm system must stabilize and adjust to the new interventions. During this time, pesticides should be made available for use as a last resort. But this didn’t happen in Kasargod. Research has shown that in cashew plantations, any shift to organic farming immediately causes a loss of yield of up to 50 percent before the system recovers. Clearly organic farming, for all its benefits, is no cakewalk.

To sum it up---there was a lot more to the endosulfan issue than what was reported by the Indian and global media. In taking its decisions, India was driven by fear and possibly misled by the political motivations behind the Stockholm Convention’s decision. What it should have done instead was carry out a high-quality epidemiological study of its own, evaluate the scientific evidence, and then taken a suitable decision. It could have been the same decision as it is today, but a more meaningful one.