Toxic “forever chemicals” are increasingly being used in US pesticides, threatening human health as they contaminate waterways and are sprayed on staple foods, a study said Wednesday. Per- and polyfluoroalkyl substances (PFAS) have come under increasing scrutiny in recent years, but environmental regulations against them have mainly paid attention to sources such as industrial facilities, landfills and consumer products like certain cookware and paints. New research published in the peer-reviewed journal Environmental Health Perspectives says that pesticides used on crops including corn, wheat, spinach, apples and strawberries — and other sources such as insect sprays and pet flea treatment — can now be added to the list. “The more we look, the more we find it,” co-author Alexis Temkin, a toxicologist at the nonprofit Environmental Working Group, told AFP. “And it just emphasizes the importance of cutting down on sources and really regulating these chemicals.” Research suggests that high levels of exposure to forever chemicals weakens human immune systems, making them less responsive to vaccines and more susceptible to infections. There is also emerging evidence they may reduce fertility, lead to growth delays in children, and interfere in the body’s natural hormones. For the new paper, the authors trawled public databases and carried out freedom of information requests to obtain information on both “active” and “inert” ingredients in pesticides. Active ingredients are those that target pests, while those that are called inert are everything else. The latter are not required to be disclosed on the label even though they can increase the efficacy and persistence of the toxic active ingredient, and can be toxic themselves. The researchers uncovered a concerning trend: 14 percent of all US pesticide active ingredients are PFAS, including nearly one-third of active ingredients approved in the past decade.