The study looked at the health of streams in Maryland, USA, by calculating critical loads and stream chemistry in different areas. They used a model to consider factors like soil type, weather, and pollution levels. The results showed that some streams in western Maryland and near the Chesapeake Bay are more sensitive to pollution, while others in different regions are less affected. The researchers found that many streams in Maryland are still becoming more acidic due to pollution, but certain land-use practices can help keep them neutral.