Deep in the heart of a protected area like Doñana National Park, it is supposedly clean and free from pollution compared to other kinds of areas such as a big city's downtown area. However, it does not always work out that way, since natural environments get a growing number of pollutants. In the specific case of Doñana, we suspect this is due to its geographical location, as it is close to Huelva's chemical park and surrounded by areas with a great amount of agricultural activity.