Scientific Investigations Report 2007–5179
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2007–5179
Figure 24. Relation of chloroform detection frequency in ground-water samples collected from (A) urban and (B) agricultural areas to (C) percentage of agricultural and urban wells in each dissolved-oxygen category within regional National Water-Quality Assessment Program study units in the arid to semiarid Western United States, 1993–2004.