Freshwater Nutrient Criteria
The federal Environmental Protection Agency (EPA) requires all states to consider nutrient criteria for all waters. Nitrogen and phosphorus are nutrients that are natural parts of aquatic ecosystems and are necessary for the growth of algae and aquatic plants, which provide food and habitat for fish, shellfish and other organisms. Unlike many water contaminants for which criteria have been established, nutrients typically do not exert primary effects on aquatic life by acting as toxicants. Too much nitrogen and phosphorus in the water can cause algae to grow faster than ecosystems can handle. Significant increases in algae due to nutrient over-enrichment can harm water quality, food resources and habitats, and decrease the oxygen that fish and other aquatic life need to survive. Some algal blooms are capable of producing toxins that are harmful to aquatic life and/or human health.
This web page provides information related to past and current efforts to develop criteria designed to protect Virginia surface waters from harmful effects of nutrient over-enrichment.