In Canada, "a leading toxicologist has called for an urgent study on the potential health hazards posed by biosolids [3] -- or human sewage sludge [4] -- that is being spread on farming fields in Northumberland County." The sludge is offered as a free fertilizer by the local water and waste treatment plant. About 120,000 tons of sludge are spread on 6,000 acres of farmland in Ontario. Toxicologist Dr. Anne Mildon is treating four couples who live near fields sprayed with sludge. "They're all non-smokers are were in very good health until this past year. Then suddenly they get very sick and their blood tests show incredibly high levels of various metals," said Dr. Mildon. "Without a scientific study, you cannot definitely link their health problems directly to the biosolids but I have a growing sensation in my stomach that they are probably connected," she added. The affected families, who have experienced sudden weight loss, headaches, reduced kidney function, respiratory and other illnesses, have stopped using their properties' well water. They are petitioning their local and regional governments.