Ammonia Quality Standards
In 2013 the EPA updated their ammonia standards on ambient water quality criteria. Ammonia (NH3) itself is a toxic substance used in household cleaners, laboratories, and in over 2/3’s of overall fertilizer production in the United States. The toxicity of this compound is interesting seeing as it is fairly harmless to mammals that possess the urea cycle (a cycle that converts ammonia to a much less toxic form of uric acid) but aquatic animals don’t possess this and are therefore in great danger from any exposure to ammonia causing birth defects and infertility in species of fish and mollusks. So the EPA must set standards for water quality.
There were prior standards that had been created in hopes of bringing down pollution in waters to a level where not only human exposure wouldn’t be harmful but that of the aquatic creatures as well. The prior standards for water quality set in 1999 were made to cover all aquatic species and include the recognition of variance in pH and temperature, it’s effect on ammonia concentration and in turn those variable effects on aquatic life. Though much more thorough than the standards set in the 1980’s, the standards set in 1999 neglected the sensitivity to mussel species concerning ammonia levels.
Mussels play a key role in an aquatic ecosystem and act as a filter as they feed. During their feeding process they filter through phytoplankton, fungi, and bacteria also excreting nutrients into the water. Ammonia comes in two different water soluble forms, ionized (NH4+) and un-ionized (NH3) the latter of the two being very toxic to aquatic life. The risk of this toxicity is the responsibility of the EPA to set standards and enforce them. To do so they must compile scientific data on individual species with controls and a variable.
There are two ways that data can be expressed concerning toxicity, acute and chronic. Acute toxicity is an exposure over a short period of time with very sharp...