The dumber number game

By Sunita Narain
Published: Saturday 15 November 2003

I met an eminent economist last week. He quoted another eminent economist-cum-columnist, and asked me if it was true that apples had higher pesticide residues than Coke or Pepsi. Before I could respond, he rather menacingly concluded: "And is it not true that mother's milk has pesticide?"

Evidently, "common-sensical truths" put out by the spin-doctors of the soft drink companies -- along with actress Rani Mukerjee, who pouts: "if the air is dirty should we not breathe" in an advertisement -- had spun their way into trained minds. I won't call them gullible. Economists are not expected to read beyond numbers. And yes, it is true that pesticides detected in soft drinks were lower than the standards prescribed for pesticide residues in milk, or apples. But that is not the point.

The point is: safety. Pesticides are toxins. This is why human exposure to pesticides must be minimal. Such a demand requires that the presence of these toxins, in what we eat and drink, be strictly regulated. And regulation involves determining that amount of a pesticide to which we humans can be 'safely' exposed without our health being compromised.

Industry-inventors of the chemical and scientists work to determine what is possibly the 'safe' dose of a particular pesticide. They determine what is called an Acceptable Daily Intake (ADI) of each particular pesticide -- that is, what is safe to take in daily, over a lifetime, for what age and body weight. Therefore, safety is defined as the dose that must not be exceeded each day, of a particular pesticide. Based on the toxicity of a pesticide, the dose will differ. The dose will also differ based on the weight and age of the person. So, for instance, it may be 'safe' to ingest 0.3 mg of lindane for an adult with a bodyweight of 60 kg, but a child with a bodyweight of 10 kg is only allowed 0.05 mg of lindane each day.

Once the ADI has been set, regulators have to estimate if our exposure to the pesticide is exceeding this safety limit. How is it done?

First, scientists supervise pesticide usage in different crops. On this basis, they measure the minimum pesticide residue level achievable under good agricultural practices. This helps to determine the archstone of real pesticide regulation: what is called the MRL, or maximum residue level, in food for a particular pesticide. This MRL -- the least legally acceptable amount of pesticide residue -- is then used to calculate exposure.

You will have guessed that exposure occurs through the food we eat. Regulators have to have a clear idea of what our diet consists of -- cereals, pulses, vegetables, literally each apple if you like. Then, based on the individual MRL for every kind of pesticide residue found in each diet item, the total actual exposure is calculated. This is the regulatory challenge: the total exposure cannot exceed ADI. If it does, it's back to the drawing board. A way has to be found to reduce the amount of pesticide residue permissible in each crop, and food item, so that the total intake of the toxin is reduced. And remember, this has to be done for each pesticide.

Global regulators -- the Food and Agriculture Organization; the World Health Organization -- have developed regional diet charts to help estimate our exposure to the pesticide. But they say that each country that registers and uses pesticides, in order to ensure that exposure does not exceed ADI, needs to do its own homework. To exceed ADI would be criminal. As it would be deadly.

Now, what has all this to do with soft drinks or apples? The answer is in re-writing an old adage: while an apple a day still keeps the doctor away, a soft drink does not.

Let me explain. What is 'safe' means calculating what we eat, how much we eat and how much pesticide can be allowed in all this. The food basket is also the pesticide basket. We have to ingest pesticides because we need nutrition, but we must not exceed our quota. Call this the nutrition-poison trade-off. So long as we cannot wish away pesticide use, it is imperative that this trade-off is a prudent one.

It will come as no surprise that soft drinks are never included in global or national diet calculations. Soft drinks are not essential foods, at least not till now. Therefore, if any pesticide residues are allowed in the soft drink as 'safe', the drink will have to be 'fitted in' into the calculation of how much residue we can safely ingest daily on the whole. In other words, some essential food item will have to be thrown out of our diet basket. (And we are not even talking about residues in water, because water is still not adjusted in the daily diet). What would the economists want us to substitute for the sake of soft drinks -- Milk? Apples? Fruit juices? Cereals?

'Safety', therefore, is about setting and adhering to standards for pesticide residue in food products. If no standard has been set, then the product -- soft drinks in this case -- has no 'business' containing pesticide residue in it. It is unsafe. No, it is unacceptable.

Safety is not about playing the dumber number game. Tiny and continuous exposure to a cocktail -- multiple residues -- of pesticides in soft drinks would be deadly. Consider chlorpyrifos -- a pesticide we detected in soft drinks. It can pass through the placenta; so if pregnant women are exposed, even at low doses it can damage the unborn. Now scientists are finding that infants are also more vulnerable -- they produce less of the enzyme that helps to detoxify the body of this pesticide residue.

Can you still call these drinks safe? Only if you are acting. Like Aamir Khan.

-- Sunita Narain

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