Today’s groundwater is tomorrow’s drinking water.

So warned a far-reaching 2010 report on the rising number of leaks and spills from nuclear power plants and their spreading threat to water resources – groundwater, surface water, and drinking water wells — from radioactive contamination.

Leak Now, Fix Later, published by Beyond Nuclear, investigated a series of massive leaks at nuclear plants and found that its close ties with the nuclear industry kept the federal Nuclear Regulatory Commission from taking needed enforcement action to address the problem.

The NRC has allowed the nuclear plant operators to self-regulate the problem through ‘voluntary initiatives’, at the same time it has downplayed — and deceptively misrepresented – the health threat from exposure to tritium – the most pervasive radioactive contaminant released in nuclear plant operations, the report found.

In its investigation last year on safety issues linked to the U.S. fleet of aging nuclear plants, the Associated Press reported that two thirds of all U.S. plants have leaked radioactive tritium into groundwater. These leaks – which in some cases have continued and gone undetected and unreported for years at a time – are most often due to corrosion in underground pipes that are not properly maintained or inspected.

Now comes a new report released in January that again raises the alarm over the epidemic of radioactive leaks from nuclear plants.

Too Close to Home: Nuclear Power and the Threat to Drinking Water (published with an interactive map showing operating and proposed plant sites) focuses on the impact on drinking water supplies for people living within the 50-mile emergency planning zone of U.S. nuclear plants.

Nuclear power plants draw their cooling water from nearby sources of waterways, which makes these sources the “natural destination for spilled or dumped radioactive liquid, and put[s] them at risk of contamination in a Fukushima-type accident,” the report states.

The report recalls the nuclear catastrophe in Japan a year ago at the Fukushima Daiichi nuclear plant where three nuclear reactors had meltdowns, releasing massive amounts of radiation that contaminated drinking water sources as far away as Tokyo (130 miles from the plant.)

Over 80,000 people have been evacuated from their homes due to airborne radiation, which has left nearby land areas uninhabitable for decades to come. Radioactive contamination has been found in beef, rice, milk, vegetables and tea.

“The continued release of radioactive tritium to groundwater at U.S. nuclear reactors—releases that, while they pose only a tiny fraction of the danger imposed by a Fukushima-type accident, are steadily ongoing and signal deep reason for concern about the safety of the nation’s aging nuclear fleet,” the report states.

Of the 66 nuclear plant sites in the U.S. 44 draw cooling water from inland bodies of water, and the 22 others draw from three Great Lakes (Ontario, Michigan, and Erie), ocean water or another source.

Tritium is a radioactive isotope of hydrogen that is produced in nuclear reactors. With a half-life of 12.3 years, it remains a biological hazard for about 120 years. Because it is incorporated into water molecules in place of ordinary hydrogen, it is easily absorbed into plant, animal, and human tissue.

Tritium exposure—which can be chronic for people living around a nuclear plant—is linked to cell damage that can result in cancer and reproductive defects and raise the risk of genetic abnormalities in future generations.

In addition to leaks from underground pipes, the report points out that rainstorms increase the risk to drinking water supplies from airborne radioactive emissions.

By capturing particles and washing particles deposited on land into waterways, the result is a “sudden infusion of radionuclides into bodies of water, including rivers and reservoirs that provide the source for drinking water systems,” the report states.

Airborne emissions occur both during the routine operation of a nuclear plant under “allowable” limits permitted by the NRC, and during “venting” when steam is released to the atmosphere to cool a reactor following an accident.

Such venting occurred in recent leaks reported at the San Onofre nuclear plant in California and the Byron nuclear plant in Illinois.

NRC spokespersons repeated reflexively that there was no risk to the public from either leak, but those statements were challenged and in California, a citizens’ protest at a San Clemente city council meeting called for independent radioactive monitoring (“Nuclear Critics Continue Pleas for Independent Radiation Monitors, Cancer Studies”).

Too Close to Home says the “most significant tritium leaks of the past 10 years” occurred at the Salem and Oyster Creek plants in New Jersey, the Indian Point plant outside New York City, the Braidwood plant in Illinois, and Vermont Yankee in Vermont. All were massive releases of contaminated water, and initially went undetected, unreported or involved other deception by the plant’s corporate owner.

The report calls for shutting down nuclear plants currently in operation when their operating licenses expire, and for ending all federal subsidies for nuclear power.

“Adopt policies to expand energy efficiency and production of energy from clean, renewable sources such as wind and solar power, such as tax incentives and a renewable energy standard.”

Too Close to Home was published by the Environment America Research & Policy Center and the US Public Interest Research Group Education Fund.