The state’s Department of Environmental Protection’s latest response to Keystone Landfill’s 42-year expansion request lists 60 items in need of clarification, not the smallest of which is the landfill’s assurance that leachate runoff (water that percolates down through the successive tons of buried garbage) will fall to roughly 25 percent or current levels despite the landfill being significantly larger. It seems like a bit of magical thinking, to be sure.