Variable | Nitrate concentration | Likelihood of high nitratea | ||
---|---|---|---|---|
Percent change (95% CI) | p-value | Percent change (95% CI) | p-value | |
Percent Black, non-Hispanicb | −1.3 (−1.5, −1.0) | < 0.0001 | −4.3 (−5.7, −2.9) | < 0.0001 |
Percent Hispanicb | 1.8 (1.6, 2.0) | < 0.0001 | 1.9 (1.4, 2.4) | < 0.0001 |
Percent povertyb | −0.8 (−1.2, −0.3) | 0.0004 | −2.2 (−3.7, −0.7) | 0.004 |
Percent home ownershipb | --f | −0.7 (−1.9, 0.4) | 0.214 | |
Percent urban householdsb | 0.0 (0.0, 0.1) | 0.14 | 0.4 (0.2, 0.6) | < 0.0001 |
System size: Smallc | 9.0 (4.6, 13.7) | < 0.0001 | −21.8 (−31.6, −10.5) | 0.0003 |
System size: Mediumc | 15.8 (9.2, 22.8) | < 0.0001 | −24.8 (−40.4, −5.1) | 0.016 |
System size: Largec | 36.2 (27.1, 45.9) | < 0.0001 | −10.0 (−30.6, 16.7) | 0.426 |
System size: V. Largec | 51.0 (28.2, 77.9) | < 0.0001 | 54.1 (−20.4, 199) | 0.200 |
Source water: Groundwaterd | 33.9 (26.4, 41.9) | < 0.0001 | 311 (201, 460) | < 0.0001 |
Percent croplandb | 0.6 (0.5, 0.8) | < 0.0001 | 3.3 (3.0, 3.7) | < 0.0001 |
Livestock per 100 acresb | 0.1 (0.0, 0.2) | 0.008 | 0.2 (0.0, 0.5) | 0.107 |
Region: Northeaste | 84.0 (6.0, 219) | 0.030 | 69.1 (−41.7, 390) | 0.333 |
Region: Southe | 58.5 (−1.7, 156) | 0.059 | 106 (−18.5, 418) | 0.127 |
Region: Weste | 88.1 (13.9, 211) | 0.014 | 270 (44.7, 849) | 0.006 |