Reuters: Tests are underway to determine if a green film shimmering on the surface of Portland's Willamette River may mark the return of toxic blue-green algae that could be dangerous to both people and animals, officials in Oregon said on Thursday. The concerns come as dozens of people from across the country have signed up to participate in the 10.7 mile Portland Bridge Swim at the weekend, said Travis Williams, executive director of Willamette Riverkeeper, a nonprofit that reported algae concerns to public...