How are water quality standards determined?
Distinguish between water quality criteria pollutants and maximum contaminant levels. Water quality standards are determined by the Environmental Protection Agency (EPA) which has the responsibility to carry out the goal to restore and maintain the chemical, physical, and biological integrity of the nation’s waters. Water quality pollutants such as pesticides, cleaning solvents, and detergents are found in water due to the activities of humans. Other pollutants such as nutrients and sediments are a problem only under certain conditions. Maximum Contaminant Levels (MCL) is enforceable under the Safe Drinking Water Act (SDWA). Drinking water standards are much stricter on the safety of water. Due to the risk of cancer the MCL was lowered to 10 L from 50L because 50L was too high. If these pollutants are not filtered out of the water they can cause harm to the plants, animals, and human bodies. EPA has to approve the safety of the water before it can be used. According to EPA 92% of the people in the U.S. have access to drinking water that meets the drinking water standards. However over 42,000 rivers, lakes, and estuaries are not meeting the recommended water quality standards.
The major problems with these waters are pathogens, mercury, nutrients, other heavy metals, sediments, and oxygen depletion. The waste waters need to be safe also and to keep them safe they have to be treated and manage properly. Sometimes the waste waters receive two treatments. The waste waters need to be free of debris and grit, particulate organic material, colloidal and dissolved organic material, and dissolved inorganic material. These material needs to be removed from the waste waters because they can clog drains and sewage causing foul odors and discoloration of the water. When it rain and debris is in the street the city workers clean them up quickly to avoid drainage problems. If they didn’t clean it up from the streets we will experience street flooding. People please help by keeping the drains clear of things that can harm the drainage system.
Wright, Richard T. Environmental science : toward a sustainable future / Richard T. Wright, Dorothy F. Boorse. – 11th ed. p. cm.