A pair of hazardous chemicals used for decades in firefighting at Joint Base McGuire/Dix/Lakehurst have contaminated ground, surface, and drinking water on and near the base, a spokesman said last week, with tests showing levels 20 to thousands of times higher in some samples than federally recommended standards. Three of 131 private wells tested at homes off the base show evidence of the fluorinated chemicals known as PFOS and PFOA, Staff Sgt. Dustin Roberts said Friday, with one home’s drinking water containing 1,392 parts per trillion. The Environmental Protection Agency’s health advisory for these chemicals has set 70 parts per trillion as its recommended level. Roberts said the base was providing the affected homes with bottled water and was studying ways to remediate the problem. None of the affected private wells serve schools or other public institutions, he said. Two shallow wells that provide drinking water to the base showed levels as high as 215 parts per trillion, according to Roberts. He said he did not know how much of the base’s drinking water comes from…