Pesticides are one of the few kinds of chemicals specially designed to kill living things that we intentionally put into our environment in high volume. A large class of pesticides are the organophosphates (OPs), agents that affect the normal process of nerve impulse transmission.
What we call pests are one kind of organism they can kill, but OPs are unaware of our human categories like “pest.” They are also adept at killing and sickening other organisms. Like us. They do it frighteningly often in the developing world, and they do it in the developed world as well. There is a nice Jack Woodall column in The Scientist about a new biotech solution to OP pesticide poisoning using genetic engineering to produce butyrylcholinesterase (BChE), a natural protein that counteracts the effects of these nerve poisons. The natural BChE only exists in microgram amounts in the blood. The new biotech method can produce it in kilogram quantities. Ready Woodall’s account for more details on the BChE effort. But his brief review of the public health problem of OP poisoning is worth a pull quote:
Despite using only 25% of the world’s pesticides, developing countries are home to 99% of pesticide-related deaths.
In the year 2000, hospitals in six Turkish cities were flooded by 2,000 students with poisoning symptoms after eating hazelnuts. Fortunately, nobody died. The nuts had been stored for a long time in a grain depot disinfected with an organophosphate (OP) pesticide.
The problem of pesticide poisoning is most acute in developing countries, where workers mix OP pesticides and spray fields without using gloves, goggles, or protective clothing, and then enter sprayed areas without waiting a safe interval. Despite using only 25% of the world’s pesticides, these countries are home to 99% of pesticide-related deaths.
It’s not just a problem in the developing world: In 1998 in California, all 34 workers fell ill after returning to weed a crop sprayed with an OP pesticide without waiting the recommended 48 hours. One was hospitalized. (Eating food treated with OPs is, of course, not nearly as harmful as swallowing heavily contaminated nuts or walking in newly-sprayed areas.)
A 2005 report on the International Workshop on Secure Access to Pesticides in conjunction with the Annual Congress of the International Association for Suicide Prevention, Durban, South Africa, estimated that there were 3 million cases of pesticide poisoning resulting in as many as 300,000 deaths per year, more than 100,000 of them in China. There’s another risk: In rural areas, a significant percentage of people attempting suicide (up to 90%, in Malaysia) use pesticides, and close to 80% of all pesticide-related attempted suicides use OPs. This is a situation that needs some kind of a solution. Enter the military. (Jack Woodall, The Scientist)
Death and acute illness are just one of a large number of bad outcomes. For example, in South Africa empty pesticide plastic bottles are often used to carry drinking water from the stream or spring. A case control study a couple of years ago suggested that babies born to women who used plastic containers for fetching water were over six times as likely to have a baby with a birth defect.
Maybe the use of butyrylcholinesterase will be an important way to prevent pesticide poisoning. Here’s another. Stop using pesticides except under the most urgent of circumstances. We shouldn’t be surprised that people are being poisoned by chemicals that have been designed to be poisons. We should be surprised that they are often portrayed as harmless to humans but deadly to organisms who share much of our basic neurophysiology.