Heavy use of the world's most popular herbicide, Roundup, may be linked to a range of health problems and diseases, including Parkinson's, infertility and cancers, according to a new study. The report, published this month in the online journal Entropy, said evidence indicates that residues of glyphosate, the chief ingredient in Roundup and other weedkillers, has been found in food. Those residues enhance the damaging effects of other food-borne chemical residues and toxins in the environment to disrupt normal body functions and induce disease. "Negative impact on the body is insidious and manifests slowly over time as inflammation damages cellular systems throughout the body," the study says. Environmentalists, consumer groups and plant scientists from several countries have warned that heavy use of glyphosate is causing problems for plants, people and animals. Monsanto is the developer of both Roundup herbicide and of crops that are genetically altered to withstand being sprayed with the weedkiller. These biotech crops, including corn, soybeans, canola and sugarbeets, are planted on millions of acres in the United States annually. Farmers like them because they can spray Roundup directly on the crops to kill weeds in the fields without harming the crops. Roundup is also used on lawns, gardens and golf courses.