The amounts of these chemicals are small and often considered “acceptable,” but scientists now know that they have a cumulative effect. Many chemicals that we use very casually on our lawns cause long-term health problems in ways that have only recently been understood. They “disrupt,” or throw out of whack, the endocrine system, made up of glands and hormones that control almost every aspect of our bodies’ functions.
In 2009 the Endocrine Society, a group of doctors, researchers and educators who specialize in diseases related to the hormonal system, published a scientific statement based on 485 citations from research papers showing growing evidence that there are significant health threats caused by endocrine-disrupting substances in our environment. In terms of scientific research, 2009 is relatively recent. Epidemiologic studies take decades, and developing a battery of reliable laboratory tests also takes many years. This means that there are more studies implicating older chemicals, many of which are no longer sold because of known toxicities.
But many scientists expect similar chemicals now in widespread use to cause the same problems. Endocrine disrupters are linked to an increased risk for breast and prostate cancer, thyroid abnormalities and infertility. The Endocrine Society paper and others also present evidence that links exposure to chemical contaminants to diabetes and obesity.