Final answer:
Saltwater intrusion can lead to contamination of well water, potentially introducing sodium and chloride ions, along with various other pollutants like VOCs and heavy metals, especially in areas near fracking operations and other common sources of groundwater pollution.
Step-by-step explanation:
Saltwater intrusion can cause the water in wells to become contaminated with a variety of substances, including sodium and chloride ions due to the mixing of seawater with freshwater aquifers. In the context of oil and gas extraction, such as hydraulic fracturing (fracking), the potential for groundwater contamination is significant due to the multitude of substances used in the process.
Fracking fluid, which may contain heavy metals, radioactive materials, volatile organic compounds (VOCs), and hazardous air pollutants like benzene, toluene, ethylbenzene, and xylene, poses a risk when it enters the groundwater. Besides fracking fluid, there are other common sources of groundwater pollution, including septic systems, agricultural runoff, landfills, and leaking underground fuel storage tanks. These can result in contaminants like nitrate, pesticides, and petroleum products entering the groundwater supply, sometimes forming expansive plumes of pollution.