"Women who drink water contaminated with low levels of the weed-killer atrazine may be more likely to have irregular menstrual cycles and low estrogen levels, scientists concluded in a new study. The most widely used herbicide in the United States, atrazine is frequently detected in surface and ground water, particularly in agricultural areas of the Midwest. The newest research, which compared women in Illinois farm towns to women in Vermont, adds to the growing scientific evidence linking atrazine to altered hormones."