KUOW: Proposals to make the Northwest a major coal exporting region have made for a familiar debate over the potential impacts on people and the environment. Will it help the economy? What will coal dust do to the air we breathe? Will our rivers and marine waters be threatened? Here’s another question: Will coal trains harm the wetlands of the Pacific Northwest? So far, wetlands have not been a central part of the public debate over coal exports. But concern over these ecologically sensitive areas are…