TABLE 3.
Region | Nonvirgin soil samplesb
|
Virgin soil samplesc
|
||||
---|---|---|---|---|---|---|
No. positive | Total no. | % | No. positive | Total no. | % | |
Central | 89 | 397 | 22.4 | 31 | 88 | 35.2 |
Northeast | 9 | 151 | 6.0 | 3 | 119 | 2.5 |
Northwest | 60 | 174 | 34.5 | 25 | 109 | 22.9 |
South | 59 | 288 | 20.5 | 13 | 202 | 6.4 |
West | 147 | 338 | 43.5 | 36 | 143 | 25.2 |
Total | 364 | 1,348 | 27.0 | 108 | 661 | 16.3 |
Differences in the prevalence values for virgin soils and nonvirgin soils were significant (P < 0.001) in all cases.
Nonvirgin soils were defined as soils that had been changed by people (cultivated, urbanized, and industrialized soils).
Virgin soils were defined as soils that had not been changed by people.