Hanford has taken its best look in decades at shoreline contamination along the 300 Area, setting a baseline to track future pollution in that region.

The most immediate bottom line: Most river water is safe to drink. One spot exceeded federal safe drinking water standards.

Pacific Northwest National Laboratory and Washington's Department of Health recently released a report on radioactive and chemical contaminants on the land and water sides of the Columbia River's shoreline next to Hanford's southeastern tip.

The two agencies separately analyzed water, plant and animal samples from August to October 2001. They double-checked their results with each other, agreeing on most findings.

This was the most extensive sampling of the 300 Area's shoreline area since 1971, when Hanford's second-to-last plutonium production reactor shut down.

The 300 Area is a crowded group of buildings where nuclear fuel was assembled and numerous tests of radioactive materials were conducted. Much of the ground beneath it is contaminated.

Two major underground radioactive plumes hit the shoreline east of the 300 Area.

One is a uranium plume fanning northeast, east and southeast from the 300 Area. The second is the southernmost tip of a huge tritium plume flowing from central Hanford.

In the overall Hanford picture, the tritium plume is relatively benign.

However, the state-PNNL study shows uranium and some daughter substances -- isotopes of other elements created and left over from decaying uranium exceeding federal drinking standards. That occurs from ground water seeping up from one spot in the Columbia River's bottom just offshore of the uranium plume's center.

Sampling points upstream and downstream of that spot show uranium levels within federal safe-to-drink concentrations. Once uranium-laced ground water enters the river, the Columbia's huge volume dilutes to it to much sparser concentrations.

Federal drinking standards assume a steady consumption of that contaminated water for at least a year, and often longer.

The study looked at numerous radioactive, nonradioactive and toxic substances on the land and in the river. Some substances showed higher concentrations than found at Vernita Bridge -- indicating the higher levels come from Hanford-related contamination. But the concentrations of those substances were within safe drinking limits, the report said.

While the uranium found in this study comes from the 300 Area, it is difficult to say if more uranium will flow through the ground water into the river, said Ted Poston, manager of PNNL's environmental surveillance program, and one of the five scientists who wrote the report.

That's because uranium normally binds to the soil. It moves very slowly, or sometimes not at all through the soil.

The 300 Area's shoreline region "is not a drinking source, and it is unlikely to become one in the near future," Poston said.

The study looked at three scenarios in which people would drink water in that area.

One has a person staying in a boat and drinking his own water -- receiving zero radiological contamination from Hanford.

The second has someone stepping on the shoreline, drinking 1 liter of river water and eating a half-pound of clams from the river. That person would absorb a radioactive dose of 0.16 millirem.

The final scenario has a scientist spending two days on that shore and drinking a total of 4 liters of river water. That translates to a dose of 0.044 millirem.

The maximum allowable Hanford-related dose for a non-Hanford person is 100 millirem a year, according to Department of Energy regulations. That's drastically greater than the doses absorbed in the study's three scenarios.

The study examined concentrations of chemicals, metals and radioactive substances in mulberry bushes and sweet clover growing along the shore, as well as in mice, mayflies and darkling beetles. In the river, the study looked at samples of sculpin, crayfish, Asian clams, milfoil and periphyton.

Some samples showed elevated levels of metal, chemical and radioactive substances. Some did not.

The clams, which stay in one area of the river, appear to be well suited to track long-term accumulations of contaminants in the river -- followed by the crayfish and sculpin, Poston said.