Final answer:
The most critical water quality concern involves primary contaminants like heavy metals and pathogens. Secondary concerns affect water aesthetics and include substances like iron and zinc. The EPA regulates water quality, with surface and groundwater pollution stemming from a variety of sources including agriculture and industrial activities.
Step-by-step explanation:
The most important water quality concern is the presence of potentially toxic substances, such as heavy metals (e.g., mercury, arsenic, uranium) and pathogens, which can pose major health risks even in small amounts. These are classified as primary contaminants under the National Primary Standards for Drinking Water.
Several secondary quality concerns include the aesthetic aspects of water (such as color, taste, and odor), less toxic species (like iron and zinc), and factors like turbidity, which can also impact the quality and safety of water. These concerns, while not as critical to health as primary contaminants, can still affect the overall acceptability of drinking water.
Two main sources of surface water pollution are agricultural runoff caused by the use of pesticides and fertilizers, and industrial discharges. For groundwater pollution, common sources include septic systems and underground storage tank leaks.
In the United States, the Environmental Protection Agency (EPA) set forth water quality standards to protect human health and the environment. The Clean Water Act has played a crucial role in governing water quality standards. Additionally, local communities are required to supply annual consumer confidence reports, informing the public about the quality and contaminants of their drinking water.