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National Drinking Water Database


National Drinking Water Database - Chemical Contaminants

Radon


Status: Unregulated - EPA has not established a maximum legal limit in tapwater for this contaminant.

Radon is a radioactive breakdown product of radium and uranium in soil, rock and water; it is often present in groundwater. [read more]

 
Detected
Found above
health guidelines
Found above
legal limit
States
22
19
-
Water utilities
1,300
1,296
-
People Served
32,696,864
32,256,096
-

Health Concerns for Radon:


Radon Exposure by State

Water utilities in 22 states have reported detecting Radon in treated tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies.

StateWater Suppliers with Radon contaminationWater suppliers reporting Radon above health-based limits
SystemsPopulationSystemsPopulation
California7923,272,8547923,272,854
Massachusetts702,270,848692,269,419
Nevada61,526,98961,526,989
Minnesota5521,223,7265521,223,726
Nebraska1171,076,7471171,076,747
Washington17871,14317871,143
Arizona6837,6836837,683
Wisconsin81484,73381484,733
Maryland29209,35029209,350
New Mexico30168,90530168,905
Maine197135,328197135,328
New York3099,6113099,611
New Hampshire7041,3207041,320
New Jersey424,753424,753
Iowa110,329110,329
Alabama21,80621,806
Vermont49304930
Wyoming14001400
Pennsylvania170170
North Carolina1409,54200
Colorado129,50000
South Dakota129700
Total1,30032,696,8641,29632,256,096

The Most Polluted Communities

1,300 water utilities reported detecting Radon in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Radon level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Governors Forest
NH
01 of 127000 pCi/L
(27000 pCi/L)
2Pinewood Acres Trailer Park
Bowdoin, ME
951 of 126800 pCi/L
(26800 pCi/L)
3Tanglewood Mobile Estates 1
Hollis Center, ME
552 of 226530 pCi/L
(25000 to 28060 pCi/L)
4Buffumville Heights Estates Condominium
Oxford, MA
401 of 125400 pCi/L
(25400 pCi/L)
5Range Pond Apts Poland Spring
Cumberland, ME
301 of 124200 pCi/L
(24200 pCi/L)
6Nichols Trailer Park
Shelburne, ME
753 of 323276.67 pCi/L
(8200 to 31926 pCi/L)
7Muirfield Village
Osterville, ME
335 of 520265.3 pCi/L
(15300 to 29500 pCi/L)
8Howards Trailer Park
Bucksport, ME
652 of 220096 pCi/L
(16592 to 23600 pCi/L)
9Bass Lake Water Company
Bass Lake, CA
3,0061 of 119915 pCi/L
(19915 pCi/L)
10Briar Court Estates
Goffstown, NH
1133 of 318483.67 pCi/L
(851 to 32400 pCi/L)

Health Based Limits for Radon

StandardDescriptionLevel
One in one million (10-6) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.1.5 pCi/L
One in ten thousand (10-4) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.150 pCi/L

Testing Summary for Radon

Are tests routinely required for Radon by federal law?No
Water suppliers reporting tests for Radon (2004-2009):1,427 of 47,576
Average testing rate for water supplier reporting tests (2004-2009):0.5 per year

Cancer

Type of concern: Reference:
Known human carcinogen Int'l Agency for Research on Cancer (IARC) - Carcinogens
Possible human carcinogen National Library of Medicine HazMap
Limited evidence of carcinogenicity NIOSH Occupational Carcinogens
Cancer - limited evidence US EPA, Air Risk Information Support Center, 2002



Government, industry, academic studies and classifications

government/industry list/academic study appears on list as classification(s)
Int'l Agency for Research on Cancer (IARC) - CarcinogensRADON-222 AND ITS DECAY PRODUCTS•IARC Group 1: carcinogenic to humans (International Agency for Research on Carcinogens)
National Library of Medicine HazMapRADON•Lung Cancer - Cancer of the lung caused by occupational exposures-all of these agents are in the IARC Group 1 (known human carcinogens): Yes;
NIOSH Occupational CarcinogensRADON•Potential occupational carcinogen according to NIOSH (National Institute for Occupational Safety and Health)
US EPA, Air Risk Information Support Center, 2002RADON•Cancer hazards: suspected
Association of Occupational and Environmental ClinicsRADON• o



references

government/industry list/academic study reference
Int'l Agency for Research on Cancer (IARC) - CarcinogensIARC (International Agency for Research on Cancer). 2008. Overall Evaluations of Carcinogenicity to Humans, as evaluated in IARC Monographs Volumes 1-99 (a total of 935 agents, mixtures and exposures).
National Library of Medicine HazMapNLM (National Library of Medicine). 2006. HazMap — Occupational Exposure to Hazardous Agents.
NIOSH Occupational CarcinogensNIOSH (National Institute for Occupational Safety and Health). 2006. NIOSH Carcinogens List (Potential occupational carcinogens). http://www.cdc.gov/niosh/npotocca.html.
Scorecard.org Toxicity InformationUS EPA, Air Risk Information Support Center. Health Effects Notebook for Hazardous Air Pollutants. http://www.epa.gov/ttnatw01/hlthef/hapindex.html, A Relational Database of Hazardous Chemicals and Occupational Diseases. Browse Haz-Map by Adverse Effects http://hazmap.nlm.nih.gov/hazmapadv.html, National Toxicology Program. 10th Report on Carcinogens (2002). http://ehis.niehs.nih.gov/roc/toc10.html
Association of Occupational and Environmental ClinicsAOEC (Association of Occupational and Environmental Clinics). 2009. AEOC exposures codes and asthmagen designation.

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