Your Body Almanac

Iowa

Every county is high-radon country, and farm-country wells need testing.

Iowa is one of only two states, with North Dakota, where EPA places every county in its highest radon-potential zone. Rural wells in farm country can carry nitrate, and winters are cold with weak sun.

01

Radon in every county

All 99 of Iowa's counties are in EPA's Zone 1, the highest radon-potential category. Radon is a radioactive gas from uranium in soil, and it is the second leading cause of lung cancer. Test every home, whatever its age or foundation.

SourcesEPA Map of Radon Zones and Supplemental Information (US EPA)Health Risk of Radon (US EPA)
Test your home for radonAs neededRadon is invisible and odorless, so a simple test is the only way to know your level. Fix it at 4 pCi/L or higher.
02

Nitrate and bacteria in private wells

Fertilizer, manure and septic systems can push nitrate into groundwater. High nitrate is most dangerous for infants and during pregnancy. Iowa recommends testing private wells every year for nitrate and bacteria, and many counties offer free testing through the state's Grants to Counties program.

SourcesPrivate Well Program (Iowa Department of Natural Resources)Private Well Water (Iowa Department of Health and Human Services)Nitrogen and Water (USGS Water Science School)
Test your private well every yearYearlyIf your water comes from a private well, have it tested by a certified lab at least once a year.
03

Weak winter sun and vitamin D

Iowa spans about 40.5 to 43.5 degrees north, around Boston's latitude, where a classic study found winter sun made no vitamin D in skin from November through February. Food sources matter more in those months.

SourcesInfluence of season and latitude on the cutaneous synthesis of vitamin D3 (Webb, Kline and Holick, 1988)Vitamin D — Health Professional Fact Sheet (NIH Office of Dietary Supplements)
Get vitamin D from foodDailyEat fatty fish, fortified milk and UV-exposed mushrooms so you are not relying on the sun alone. Ask your doctor about vitamin DYearlyIf you get little sun or few vitamin D foods, ask at your checkup whether testing or a supplement makes sense for you.