Although levels of DDT contamination are gradually falling in countries where the pesticide has been banned, new scientific research suggests that the chemicals are still a serious threat everywhere. Studies show that even small amounts of
pesticides can disrupt the working of human hormones, interfering with reproduction and the functioning of the immune system. That’s why representatives of more than 100 nations gathered at a U.N. meeting in Nairobi to work toward a global treaty that would phase out DDT and 11 other pesticides, known as the “dirty dozen.” Environmentalists say it’s possible to find alternative way to fight malaria—and get rid of DDT once and for all.