We have learned through painful experience these beliefs can be inaccurate because soil cannot adequately filter many contaminants. Many land surface activities, such as illegal industrial waste disposal, improper application of agricultural chemicals and fertilizers, inadequate urban stormwater management practices, and accidental spills can leak substances into the ground. Once in the ground, the substances move downward toward the groundwater. Some nutrients in water, such as phosphorus, are filtered and absorbed by soil before reaching the groundwater. Other nutrients, such as nitrogen are soluble and cannot be absorbed by soil particles.
Soluble nutrients are likely to contaminate groundwater.
Researchers have found that groundwater nutrients can also contaminate streams, lakes and areas downstream, such as the Chesapeake Bay. Bodies of water like the Chesapeake Bay can tolerate a certain amount of nutrients. In fact, without nutrients aquatic life could not exist. Nutrient overloads, however, can produce algae blooms. As a bloom grows, it covers the water's surface, preventing sunlight from reaching bottom-dwelling plants and animals and causing death.