Nitrate levels in the water are higher than permitted.
Explanation:
Groundwater supplies drinking water in eastern Washington's Columbia Basin. Approximately 20% of all monitored wells in Adams, Franklin, and Grant Counties had nitrate concentrations above the US Environmental Protection Agency's nitrate contamination threshold. After getting approval from the Washington State Department of Ecology, the Columbia Basin Ground Water Management Area was set up in February 1998. At first, the main goal was to lower the amount of nitrate in the ground water.
I think the answer is between b and c. But the answer that I heard of in history class would be C. The fact that immigrants took away high paying jobs from union members.
