IN THE EARLY 1970s, the city was up in arms about the dangers of lead poisoning to children. Ingestion of old, peeling paint, found in homes in lower-income areas of the city, was said to be the cause of brain damage and growth retardation in children under the age of six. The cure was thought to be simple - remove or cover the offending paint - and, to the extent thatthis was done, it seemed to work. So most people stopped worrying.

Now a study conducted jointly by the D.C. Environmental Health Administration and the Howard University Medical School seems to have uncovered significant evidence that the problem of lead poisoning may be a lot more complicated and pervasive than it was thought to be just a few years ago. Indeed, the evidence is so startling that its validity has been questioned by members of the Committee for Lead Elimination in D.C. Dr. Bailus Walker, who conducted the study and who is director of the city's Department of Environmental Health and an adjunct professor at Howard's medical school, is already planning further tests to verify his original findings.

The study examined 500 youngsters who live in the relatively well-to-do Georgetown, Burleith, Cleveland park and Glover park areas of the city. What it suggests is that even children who don't live in the "lead belt" - the run-down, lower-income neighborhoods where undernourished children are more likely to get their hands on paint peelings - have a surprisingly high level of lead in their bodies. What's worse, the study isn't able to come up with an explanation of why this is so. The cause could be dust inhaled from old paint, automobile emissions, lead somewhere else inthe environment or a combination of all of these things. What the study did find is that the children in Northwest who live closer to streets with heavy traffic have a higher level of lead in their bodies than children who live farther from the street. Again, the actual cause of these high lead levels isn't clear.

But it is clear that this study may have uncovered a serious problem. We think the first thing to find out is whether further tests support the study's conclusions. If so, every effort should be made to examine youngsters throughhout the city for the level of lead in their systems. Private physicians could presumably make this a part of regular check-ups, but public clinics and schools obviously would have to bear most of the burden. This might prove costly, but it would be a necessary precaution.

As for the source of the leaaa in the firstplace, all we have now is a suggestion that keeping high levels of lead out of children's bodies isn't just a matter of keeping chipping paint out of older homes in poor neighborhoods. If further tests validate the original findings, we will know pretty conclusively that lead poisoning is not a problem only of low-income areas - and not uniquely a problem of Washington, either. If it exist in this city, it is logical to suppose that it exists in other cities. And that might be reason enough for the Department of Health, Education and Welfare to move into the case. If lead poisoning is a nationwide phenomenon, then HEW's help might be necessary in the search for its cause - and for its prevention.