Pesticides and herbicides residues
The cotton plant is susceptible to many diseases, pests and weeds. Cotton production requires large amounts of pesticides and herbicides throughout the growing season, resulting in residues in the environment and in cotton products (Edwards et al., 2009).
GM cotton
Cotton is one of the leading crops to be genetically engineered. Genetically-modified Bt cotton resistant to various insect species (notably bollworm moths) was introduced in 1996 and other GM cotton cultivars (notably herbicide-resistant ones) have been released since (O'Brien et al., 2005). Genetically modified cotton is widely grown and represented 65% of the total cotton planted worldwide in 2010 (21 million ha out of 32.3 million) (Ikitoo, 2011; USDA, 2010). The main expected environmental benefit from the use of Bt cotton is a reduction in pesticide use and in residues in the environment, feeds and foods (Edwards et al., 2009). Animal studies have failed to demonstrate noxious side-effects to the use of GM cotton (EFSA GMO Panel, 2008). However, like for other GM crops, both the environmental benefits of GM cotton and its effects on health remain highly controversial and a matter of debate.