RICHMOND -- Nearly two-thirds of Virginia's monitored rivers and streams and the vast majority of its lakes and estuaries are polluted enough to be considered impaired, according to a state report that was summarized Tuesday by government officials.

State officials said the massive report does not conclude that Virginia's water quality is deteriorating, because the state is assessing more areas and adapting to changes in water quality standards. But environmental advocates said increases in impaired waters point to the need for aggressive measures to curb pollution.

"The bottom line is that where they go testing, they are typically finding problems, finding pollution," said Ann Jennings, the Virginia executive director of the Chesapeake Bay Foundation.

About 9,000 miles of rivers and streams, more than 109,000 acres of lakes and reservoirs and 2,200 miles of estuaries are impaired, according to the report. That means they fail to fully support at least one of six categories of uses, such as swimming, fishing and aquatic life.

While the totals represent significant increases from the last DEQ study released in 2004, agency officials said they do not necessarily represent a trend. The latest report represents a five-year assessment of more than 14,282 miles of rivers and streams, 112,479 acres of lakes and 2,385 square miles of estuaries.

"You need to look at our numbers in the context of the fact that we're looking at more places and that we're holding ourselves to tougher and tougher standards than we ever have before," said David Paylor, the director of the Virginia Department of Environmental Quality, who outlined aspects of the agency's biannual water quality report during a press conference Tuesday.

Bacteria, including fecal bacteria, remain the primary contaminants of rivers and streams, Paylor said.

The list of "new impairments" in the 2006 report also reflect PCB contamination found in fish tissue, a problem that has led the state to issue fish consumption advisories for portions of the New, Roanoke and James rivers and for portions of Claytor and Smith Mountain lakes. Polychlorinated biphenyls were used for decades in industry as coolants and lubricants. Mercury and PCB levels were among the new impairments cited for those bodies of water in the report.

Fecal bacteria and E. coli bacteria contamination also has impaired certain streams and river segments in the New, Roanoke and James river basins, largely for recreational use. But in most cases the pollution levels do not pose imminent threats to public health, said Darryl Glover, DEQ's water quality and assessment manager.

DEQ officials also pointed to good news in the report, which includes an update of trends at 261 monitoring stations since the agency's 2000 study. Nearly 20 percent of those stations showed reductions in levels of bacteria, the leading contaminant of rivers and streams. The remaining 80 percent of the stations showed no trend.

Glover said the improvements could be attributed to better management practices by farmers and to droughts that diminished runoff into rivers and streams.

But Jennings said the overall numbers should cause concern. She said the report underscores the importance of the state's increased spending on water quality programs. The new state budget includes $200 million for Chesapeake Bay cleanup efforts and $17 million for water quality upgrades in areas outside of the Chesapeake watershed.

On the Net: www.deq.virginia.gov