Table 4 Comparison of regression results for nitrate in community water systems using city- and county-level demographics
Variable | City Demographics | County Demographics | ||
|---|---|---|---|---|
Percent change (95% CI) | p-value | Percent change (95% CI) | p-value | |
Percent Black, non-Hispanica | −0.4 (−0.7, −0.2) | 0.0016 | −0.7 (−1.1, −0.3) | 0.001 |
Percent Hispanica | 0.3 (0.1, 0.5) | 0.017 | 0.9 (0.6, 1.3) | < 0.0001 |
Percent povertya | −0.2 (−0.6, 0.1) | 0.170 | −1.9 (−2.5, −1.2) | < 0.0001 |
Percent home ownershipa | −0.4 (−0.6, −0.2) | 0.0004 | 0.3 (−0.3, 0.8) | 0.325 |
Percent urban householdsa | 0.2 (0.1, 0.3) | < 0.0001 | 0.1 (0.0, 0.2) | 0.222 |
System size: Smallb | 11.8 (5.5, 18.5) | 0.0002 | 11.4 (5.2, 18.0) | 0.0002 |
System size: Mediumb | 12.3 (3.8, 21.5) | 0.004 | 14.1 (5.6, 23.3) | 0.0009 |
System size: Largeb | 22.8 (12.2, 34.4) | < 0.0001 | 29.7 (18.6, 41.8) | < 0.0001 |
System size: V. Largeb | 21.2 (−2.5, 50.5) | 0.083 | 34.7 (8.7, 67.1) | 0.007 |
Source water: Groundwaterc | 35.8 (24.9, 47.7) | < 0.0001 | 35.2 (24.4, 47.0) | < 0.0001 |
Percent croplanda | 0.5 (0.3, 0.6) | < 0.0001 | 0.4 (0.2, 0.6) | < 0.0001 |
Livestock per 100 acresa | 0.1 (0.0, 0.2) | 0.123 | 0.1 (−0.1, 0.2) | 0.313 |
Region: Northeastd | 62.3 (−8.8, 189) | 0.100 | −13.8 (−52.2, 55.5) | 0.622 |
Region: Southd | 48.2 (−13.8, 155) | 0.155 | −3.2 (−44.7, 69.6) | 0.910 |
Region: Westd | 82.1 (2.4, 224) | 0.041 | −42.9 (−67.5, 0.2) | 0.051 |