Dear EarthTalk: I always thought cotton was eco-friendly, but I recently heard otherwise. What’s so bad about cotton? And where can I find organic cotton clothing?
—Jamie Hunter, Twin Falls, ID
There’s a lot "bad" about conventionally grown cotton—cotton grown with the aid of synthetic chemicals, that is. The Organic Trade Association (OTA), a nonprofit trade group representing America’s burgeoning organic cotton industry, considers cotton "the world’s dirtiest crop" due to its heavy use of insecticides. The nonprofit Environmental Justice Foundation (EJF) reports that cotton uses 2.5 percent of the world’s cultivated land yet uses 16 percent of the world’s insecticides—more than any other single major crop.
Three of the most acutely hazardous insecticides, as determined by the World Health Organization, are well represented among the top 10 most commonly used in producing cotton. One of them, Aldicarb, "can kill a man with just one drop absorbed through the skin," says OTA, "yet it is still used in 25 countries and the U.S., where 16 states have reported it in their groundwater."
Conventionally grown cotton also uses large amounts of nitrogen-based synthetic fertilizer—almost a third of a pound, says the OTA, to grow one pound of raw cotton. To put that in perspective, it takes just under one pound of raw cotton to make one t-shirt. Researchers have found that the fertilizers used on cotton are the most detrimental to the environment, running off into freshwater habitats and groundwater and causing oxygen-free dead zones in water bodies. The nitrogen oxides formed during the production and use of these fertilizers are also a major part of the agricultural sector’s greenhouse gas emissions.