Table 3.
Cumulative cancer risk for community water systems in Texas grouped by system size.
| Community Water System Size | Demographic Group Defined by the U.S. Census Bureau | Tercile Boundaries for Percentage of Population within a Demographic Group 1 | Total Population in the Tercile, Millions (Rounded) | Median Cumulative Cancer Risk | Jonckheere-Terpstra Trend Test p-Value 2 |
|---|---|---|---|---|---|
| Small (500–3300) |
Black or African American | ≤2.3% (T1) | 0.72 | 4.1 × 10−4 | 0.0005 * |
| 2.3–9.0% (T2) | 0.75 | 4.3 × 10−4 | |||
| ≥9.0% (T3) | 0.79 | 5.0 × 10−4 | |||
| Hispanic or Latino | ≤13.3% (T1) | 0.74 | 4.2 × 10−4 | <0.0001 * | |
| 13.3–25.9% (T2) | 0.76 | 4.2 × 10−4 | |||
| ≥25.9% (T3) | 0.76 | 5.6 × 10−4 | |||
| Medium (3301–10,000) |
Black or African American | ≤5.2% (T1) | 1.3 | 5.3 × 10−4 | 0.0598 |
| 5.2–14.5% (T2) | 1.3 | 4.8 × 10−4 | |||
| ≥14.6% (T3) | 1.3 | 5.8 × 10−4 | |||
| Hispanic or Latino | ≤17.5% (T1) | 1.3 | 5.2 × 10−4 | 0.0230 * | |
| 17.5–33.6% (T2) | 1.3 | 5.2 × 10−4 | |||
| ≥33.8% (T3) | 1.4 | 5.5 × 10−4 | |||
| Large (10,001–100,000) |
Black or African American | ≤4.2% (T1) | 2.2 | 8.0 × 10−4 | 0.9367 |
| 4.3–12.6% (T2) | 2.2 | 7.0 × 10−4 | |||
| ≥12.6% (T3) | 2.3 | 8.0 × 10−4 | |||
| Hispanic or Latino | ≤21.5% (T1) | 2.2 | 7.6 × 10−4 | 0.1826 | |
| 21.6–37.8% (T2) | 2.1 | 7.3 × 10−4 | |||
| ≥37.8% (T3) | 2.4 | 8.3 × 10−4 | |||
| Very Large (>100,000) |
Black or African American | ≤7.9% (T1) | 5.4 | 9.1 × 10−4 | 0.1684 |
| 8.0–13.2% (T2) | 2.1 | 8.2 × 10−4 | |||
| ≥14.3% (T3) | 6.2 | 7.4 × 10−4 | |||
| Hispanic or Latino | ≤26.1% (T1) | 1.7 | 8.2 × 10−4 | 0.1270 | |
| 26.1–42.9% (T2) | 5.0 | 7.9 × 10−4 | |||
| ≥43.0% (T3) | 6.9 | 9.2 × 10−4 |
1 The tercile boundaries are indicated with a single decimal digit and may appear to overlap due to rounding; actual tercile boundaries were defined with multiple decimal digits and do not overlap. 2 Trend test p values less than 0.05 are considered statistically significant and are marked with an asterisk (*).