Atrazine is an herbicide with widespread usage: 76 million pounds are used on US fields each year. In a new study reported in The journal Biology of Reproduction, atrazine is shown to interfere with hormones in the brain that initiate ovulation. The studies show that the effects on ovulation are reversible in rats that were fed atrazine and then had the atrazine taken out of the diet, confirming the relationship between blocked ovulation when they were ingesting atrazine. The primary uses of atrazine are to kill weeds, but it is also applied by certified professionals on golf courses, athletic fields and lawns. One of the heaviest times of atrazine use is during the springtime planting season.