Why We Need Numeric Nutrient Limits and How to Implement Them

Over the past few decades, pollution of lakes, streams, and estuaries by inadequately treated sewage, manure pollution, and fertilizer run-off has triggered a growing number of algae blooms, many of which are toxic. Public health has been threatened and large numbers of pets have died after swimming in toxic algae waters. Traditionally, the state used a narrative standard in an attempt to limit the effects of these pollutants. That narrative prohibits the addition of phosphorus and nitrogen in concentrations that cause an imbalance in natural aquatic flora or fauna. In practice, this standard has failed to prevent algae blooms because it is reactive in nature: violations are almost always identified after the fact.  The purpose and effect of numeric limits on phosphorus and nitrogen is to prevent algae blooms because numeric limits are like speed limit signs that prevent accidents. Numeric limits can and will serve that purpose.  Industries that discharge nutrient polluted water have mounted a major legal and political campaign to avoid regulation. That campaign failed and the task now is to implement nutrient pollution limits in practical and cost effective ways.