Mexican marijuana cartels use pesticides, herbicides that pollute US parks, forests National forests and parks — long popular with Mexican marijuana-growing cartels — have become home to some of the most polluted pockets of wilderness in America because of the toxic chemicals needed to eke lucrative harvests from rocky mountainsides, federal officials said. The grow sites have taken hold from the West Coast's Cascade Mountains, as well as on federal lands in Kentucky, Tennessee and West Virginia. Seven hundred grow sites were discovered on U.S. Forest Service land in California alone in 2007 and 2008 — and authorities say the...