O'Brien County, IA

ZIP 51231

In ZIP 51231, 2 of the 12 things we check have at least one part graded D or F.

• Drinking water: Sheldon Water Department meets every EPA legal limit; 8 contaminants are above health goals, led by lithium at 4.5× the USGS health-based screening level.
• Nearest Superfund site: Farmers' Mutual Cooperative, 8.9 miles away.
• Largest share of modeled toxic air from industry: Valero Hartley Plant (47%), mostly acrolein.
• Fine particles (PM2.5) average 6.7 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 300,032 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 51231

• Superfund sites nearbyA
• Factories and industrial sitesB
• Oil and gas wellsA
• Parks and nature nearbyC
• Air qualityB
• Drinking water qualityC
• Pesticide useF
• Neighborhood health statusC
• Past wildfire impactsA
• Past flood impactsC
• Noise levelsA
• Radiation signalsF

Based on 1 census tract · compiled October 25, 2026 · how each grade works and its sources

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