CAMBRIDGE, Mass. (AP) — When Ann McDonald went kayaking several weeks after a 2024 rainstorm, she thought the water in the Alewife Brook just outside Boston was safe. Even though sewage discharges into the brook during heavy storms, public health officials recommended waiting just 48 hours after rain for bacteria levels to drop — so when McDonald’s kayak got stuck in debris, she wasn’t concerned about dipping her arms into the water to free herself. Later that afternoon, she fell sick with