Public water supplies in nearly three-dozen Iowa cities have arsenic levels which one group says may be hazardous. The Iowa Environmental Council based its study on state D-N-R figures. The council report says at least 33 towns -may- have problems with arsenic but -don’t- violate any standards, while the water in three areas of northern Iowa -do- exceed federal limits for the carcinogen. She says there are two mobile home courts in Mason City and private development in Clear Lake where the water supplies are above federal standards.Environmental Council spokeswoman Teresa Opheim says the group is urging federal standards be toughened on arsenic in water, something the Clinton Administration was not successful in doing. Opheim says the potential hazards are strewn across Iowa.The public water supplies which the I-E-C says exceed federal standards are: Rayburn Court for Mobile Homes and Ashley Inn Motel and Trailer Court, both in Mason City, and the Oakwood Park Water Association near Clear Lake. Counties where levels are considered a possible hazard include: Cerro Gordo, Greene, Hancock, Carroll, Bremer, Scott, Woodbury, Palo Alto, Emmet, Wright, Hardin, Calhoun, Linn, Johnson, Des Moines, Plymouth, Buena Vista. For full details, surf to “www.earthweshare.org” on the Internet.In small towns and rural homes, the quality of well water may be taken for granted. The state doesn’t necessarily come around and check every private water supply.There’s no mandate to check private wells, though most counties now will test well water free for coliform bacteria and nitrates. Mike Magnant, water-safety specialist with the state department of public health, has heard the national arguments over tightening standards for arsenic in drinking water.He says though arsenic is a contaminant, it’s not often found in any Iowa water in concentrations that would pose a danger. Magnant says you’re a lot more likely to be threatened by germs in well water.He says it’s more likely there will be bacteria than chemicals, and most substances that are detected are low enough to be dangerous only over the long term. Owners of private wells can call the county health department to find out how and when they can bring a sample of water in for testing.