What are the two key concepts for this section? Explain why groundwater cannot cleanse itself very well. What are the major sources of groundwater contamination in the United States? List three...

What are the two key concepts for this section? Explain why groundwater cannot cleanse itself very well. What are the major sources of groundwater contamination in the United States? List three harmful effects of groundwater pollution. Describe the threat from arsenic in groundwater. List three ways to prevent groundwater contamination and three ways to clean up groundwater contamination. Explain why prevention is the most important approach.