A turnaround has occurred in public approval of Ronald Reagan's performance as president, according to the latest Washington Post-ABC News poll. Americans feel more positive because the economy is getting better. But before we strike up the band and release the red balloons, we should remember that while the economy looks luminous for some, the current turmoil in economic equity makes it look murky for others.

Washington economist Andrew Brimmer, a former governor on the Federal Reserve Board, put it this way in a speech last week at California's Pomona College:

"As we look beyond the near-term horizon, economic prospects are somewhat more promising. Yet for women, blacks, and members of other minority groups, the Reagan administration's de-emphasis of affirmative action will make it more difficult to share in the benefits of economic growth.

"Over the past two decades, affirmative action to promote the expansion of employment opportunities . . . has been a basic policy of the federal government," said Brimmer. "But, today, the Reagan administration demonstrates repeatedly that it is no longer committed to that goal.

"This change in attitude and policy . . . means that for the first time in 35 years the federal government is not at the forefront of the campaign to expand equal employment opportunities in the U.S."

As Brimmer pointed out, "the administration says . . . it will fight discrimination in the job market and will urge private businesses to expand employment for those who have enjoyed few such opportunities in the past, yet at the same time it has laid aside some of the best tools the federal government has had to achieve those objectives."

The normally middle-of-the-road Brimmer called on all "who are concerned with economic equity in this country . . . to press for a reversal of administration policy."

In courtrooms in Boston, New Orleans and Detroit, the Reagan Justice Department has sought to overturn major affirmative action victories. And the president is now reportedly about to name four new members, whose views are opposed to affirmative action, to the six-member U.S. Commission on Civil Rights.

The National Organization for Women has already struck out against administration affirmative action policies. "It is ironic to hear such attacks now, when some white males are sharing our economic disadvantage, about the need to judge people as individuals, when we were often not judged for our individual qualifications before we had affirmative action," said President Judy Goldsmith. She predicted that blacks, women and Hispanics would speak with their political clout. "We represent a potentially powerful alliance, and we are all looking to l984." And Rep. John Conyers (D-Mich.) is calling for a special prosecutor to determine whether the Justice Department is exceeding its authority in seeking to overturn affirmative action court settlements.

Meanwhile, it is a sad irony that just when government's own research findings indicate that about three-fourths of the new workers during this decade will be women and minorities, Reagan policies threaten to limit the chances for those groups to share fully in the expanding opportunities.

With many of the future job opportunities in the private sector and demanding a high degree of skill, it is imperative that we prepare our women and minorities for the high-tech era. But what is the motivation for them to learn if they cannot be assured of jobs when that training is completed? What hope can be held out when their own government's policies work against their getting equal opportunity?

That is why Brimmer's call to press for a reversal of administration policy is not a political move, but a reflection of concern for the country's survival. If the nation's workers aren't utilized because of their gender or color, national productivity won't be realized and economic collapse could result.

Meanwhile, the recession hasn't ended for many. The National Urban League's April Hidden Unemployment Index, which includes discouraged workers and those who are working part time, shows black unemployment to be 33.8 percent--12.8 percent higher than the Department of Labor estimates. For others, like the 2.2 million workers whose industrial jobs have disappeared never to return again, the recession may never end.

So while a majority of Americans approve of the president's handling of the economy, I'll hold off. It's too soon to break out the champagne.