Combine first 5 ingredients in a medium bowl, stirring with a whisk. Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, baking powder, and salt in a large bowl, stirring with a whisk. Cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Gently fold in blueberries and pecans. Add milk mixture, stirring just until moist (dough will be sticky).
Turn dough out onto a floured surface; pat dough into an 8-inch circle. Cut dough into 10 wedges, and place the dough wedges on a baking sheet coated with cooking spray. Brush egg white over dough wedges; sprinkle evenly with 2 tablespoons sugar. Bake scones at 375° for 18 minutes or until golden. Serve warm.