On this edition of Arizona Spotlight, heavy traffic caused by illegal immigration into the United States is causing some environmental concerns. NPR's Ted Robbins has a report on the degradation of the desert as illegal immigrants pass through. April is alcohol awareness month and three people share their stories of how they struggled with alcoholism at an early age. We go inside the Tucson Museum of Art to learn about the Papel Picado exhibit currently on display, and Sooyeon Lee has a feature story on the Tucson International Mariachi Conference.