Charging "continuing poor performance," the federal Environmental Protection Agency has withheld nearly $20,000 in quarterly funds from the District-managed laboratory at the Blue Plains regional sewage treatment plant.

The District's Department of Environmental Services was given 30 days to correct a long list of "deficiencies" in the lab, which is responsible for measuring the levels of pollutants in treated wastewater that is discharged into the Potomac River.

EPA found measurement errors of up to 109 percent in the lab's sometimes complicated tests during August. It also said work was slow and that contaminated containers were used to collect samples.

Officials in the Department of Environmental Services blamed the deficiencies on "inadequate supervision," the same point made in an EPA report. But some black employes in the lab said work was poor because the staff was demoralized by what they described as a long history of harassment and racial discrimination.

DES Director Herbert L. Tucker said department investigation found no basis for the charges. But effective Monday, the lab will have its first supervisor, Jeanne Dove, a 10-year chemist, who has been named temporary supervisor of the analytical section.

Dove was one of several black employes who went to Tucker in 1976 complaining that they had been unanle to advance within the lab. Until Dove's appointment, all supervisory positions in the 16-employe lab have been held by whites.

"I think it represents a new attitude," Dove said. "I think it's direct result of the EPA's action."

Tucker said, "I think this appointment will show there is no discrimination, if that's what some people think."

Dove said 'most workers believe that basically there is racial discrimination . . . To some extent, the quality of work had deteriorated because they're demoralized. There has been very little, if any, action from the top."

The lab's chief, Duane Geuder, who was brought in from the outside, said the complaints "go back to a long history of misunderstanding . . . The personnel feel they are stagnating and want to blame management, but it's the circumstances that are the reason . . . There are deadened positions here. It would be nice if all of us could be GS-18, but the system doesn't work that way."

However, Geuder said that "if I were in their position, it would be a point of contention that there are no blacks in supervisory positions."

In 1970, James W. Baldwin, then executive director of the D.C. Human Rights Commission, presented a report saying "evidence was found of denial of privileges and open harassment based on race" in the entire sanitary engineering department, of which Blue Plains is part.

Poor lab work could cast credibility on how effective the big treatment plant is in cleaning up the 300 million gallons of sewage that flow to it daily from the District, suburban Maryland and Virginia. District officials say the plant is operating within all the major pollution limits of its permit.