Why is Water Quality Important?
Although 75 percent of Earth is covered by water, only 1 percent of that is freshwater available for serving the municipal water needs of more than 7.8 billion people in the world today. Because of drought and pollution, that 1 percent is dwindling. That means we must do everything in our power to reduce our water usage and ensure water quality through protection and rigorous water analysis.
There are many variables that affect water quality. It’s important to know what they are and how to measure them.
While the uses will have some water quality parameters in common, each will also have standards specific to its use. Consider, for example, tests for coliform levels and salinity. While water used for landscaping must be treated for pathogens, it does not need to meet the same total low coliform levels as water used for bathing or drinking. Similarly, salinity levels vary by use. In Massachusetts, for example, sodium levels of about 50 milligrams per liter or less are considered acceptable for overhead irrigation. However, because excessive sodium in drinking water can be harmful to those with underlying health conditions, such as diabetes or hypertension, Massachusetts has determined the safe threshold to be 20 milligrams of sodium per liter of water.
Without exception, safe municipal water is becoming more expensive to produce because of increased levels of pollution, as well as the discovery of more pollutants in water. These include an ever-increasing number of pharmaceuticals that are ingested and passed on by humans, as well as industrial pollutants, such as manmade per- and polyfluoroalkyl substances (PFAS) used in industry since the 1940s.
Climate change is also increasing the cost of municipal water treatment because water scarcity requires water to be sourced from greater and greater distances. Also, algae blooms, exacerbated by climate change, can greatly increase the levels of cyanobacteria and cyanotoxins in drinking water sources.
Many of these same factors also affect the cost of municipal sewage treatment. Raw sewage must be treated before it is released back into the environment. If it is not properly treated before being released into rivers and streams, pathogens, and pollutants, including personal care products, eventually make their way through the environment and into source water.
Key to this modern prevention of water-borne diseases is the improvement of drinking water quality testing methods. This testing must be performed at various stages of the drinking water production, as well as following wastewater treatment.
There are many water-quality tests that are typically performed for municipal water systems. They include tests for water turbidity, that is, the measure of its relative clarity. Turbidity, measured in nephelometric turbidity units (NTUs), is caused by light reflecting off material suspended in the water. That material provides places for other pollutants, such as metals and bacteria. Other tests include those measuring pH. The pH of water reflects the solubility of chemical constituents such as nutrients (e.g., nitrogen, phosphorus, and carbon) and heavy metals (e.g., copper, lead and cadmium). The greater their solubility—that is, their ability to dissolve in water—the more toxic they are. Metals tend to be more toxic at lower pH because they are more soluble.
Remember, water quality is dynamic. It can be affected by human activity, as well as environmental factors at many junctures. This includes after water is treated to acceptable standards and is being transported to the consumer. And as new pollutants enter the water cycle—and as our knowledge of those pollutants expands—the importance of water quality monitoring testing only increases; it must also be dynamic and adapt to these changes.
Surface water must be tested to determine exactly what effects these factors have had. For example, physical characteristics such as temperature and clarity must be measured because they have an effect on water quality and can also serve as proxies for other variables. If turbidity levels are high, for example, this can be a sign that there is a large concentration of biological contaminant—including pathogens—present.
The chemical composition of the surface water must also be monitored to determine the level of pollutants, including salinity (for example, road salt that has washed into the water), man-made chemicals that have deposited directly into the water as effluent or indirectly because of contamination of the watershed from pesticides, and acidic aerosols (e.g., heavy metals, such as mercury, emitted from power plants and deposited in surface waters).
So, why do we monitor surface water quality? Because these factors affect human health, either directly as drinking water, through recreational activities (e.g., health effects in swimmers due to pathogens and harmful algal blooms), or through the consumption of fish and shellfish. And even though water quality is tested and various stages before it is treated and offered as drinking water, surface water monitoring can help prevent some of the contamination from happening in the first place and better prepare municipal water treatment plants down the line.
SUEZ has been producing municipal drinking water for more than 150 years. Our tools and techniques for water monitoring, testing, and treatment—even in the smallest communities—draw on our vast global experience and scientific expertise. Our water and wastewater treatment solutions for business and municipal customers have been successfully deployed on five continents. They have and can be tailored for every imaginable specific need.
Contact a representative to learn more about the municipal water treatment services offered by SUEZ North America.