State environmental regulators announced Friday that all sludge will have to be tested for the presence of an industrial chemical before being used as fertilizer or applied to land. The Maine Department of Environmental Protection announced the new testing requirement in response to growing concerns about contamination from PFAS, a group of chemicals widely used to create non-stick coatings on cookware, food packaging and fabrics, as well as in firefighting foam. An Arundel dairy farmer has blamed PFAS contamination on his farm on the treated municipal sludge he used to fertilize his hay fields for years.The per- and polyfluoroalkyl chemicals collectively known as PFAS degrade slowly and linger in the environment for long periods, leading critics to dub them “forever chemicals.” The subject of increasing scrutiny, some PFAS have been linked to cancer, liver damage, low birth weight and other health concerns.