DeForrest E Weaver, 61, a chemist and reports specialist at the U.S. Geological Survey's National Center in Reston, died Monday at Fairfax Hospital after an apparent heart attack.

He joined the survey in 1948 as a chemist in the Texas district office of the Water Resources Division in Austin, where he was responsible for the district water quality laboratory.

Mr. Weaver transferred to Washington two years later to become chemist-in-charge of the survey's national water quality laboratory.

He supervised the laboratory's activities, measuring the quality of thousands of water samples from all over the country. In 1961, he joined the Water Resources Division's reports section and was supervisor and water quality specialist in the preparation and publication of several hundred technical reports.

Mr. Weaver's honors included a special achievement award in 1976 for his part in processing a report to Congress on natural gas transportation systems in Alaska.

Born in Bellingham, Wash., he earned a degree in chemistry from Oregon State College. From 1938 to 1942, while earning a master's degree in education from Oklahoma University, he taught science in the Muskogee, Okla., public school system.

During World War II, Mr. Weaver worked as a chemist for the Army at Camp Gruber, Okla., and took further graduate studies at Oklahoma University.

He was a member of the American Chemical Society and the American Water Works Association. He was active in the Northern Virginia section of the American Academy of Sciences and was a guest lecturer at high schools and clubs in Fairfax County.

He is survived by his wife, Ruth, of the Home in Fairfax; two daughters, Deanna Silas, of Springfield, Va., and Valendon Wally, of Roselle, Ill.; a brother, Mark, of Oklahoma City, and one grandchild.