Four Nobel Prize winners and about 10,000 of the country's leading scientists are expected to participate in the American Chemical Society's 186th national meeting this week, the group said. The meeting, which started yesterday and runs through Sept. 2, is being held at the Washington Hilton Hotel, several other area hotels and the Washington Convention Center.

Beginning today, seminars will be presented on topics such as dioxin testing, plastics, robotics, acid rain, anticancer therapy and federal carcinogen regulation, shark repellant and a new rodenticide for use on toxin-resistant rats.

About 4,000 scientific papers are scheduled to be presented and an estimated 170 exhibitors will display research equipment, computer data services and other products available to research chemists.

For further information on the conference, call 483-3000, ext. 1251.

Mark S. Matthews has received the Association of Government Accountants' achievement of the year award for outstanding achievement in improving financial management in government. Matthews is a financial analyst with the Agency for International Development.

Alexander Whitney Jr. has been named president of the Consulting Engineers Council of Maryland. Whitney is a founding partner of the Baltimore County engineering firm of Whitney, Bailey, Cox & Magnani. He succeeds Herbert R. Plitt of Century Engineering Inc. Other officers elected were: Martin J. Hanna III of Hanna Engineering Corp., vice president; Eugene C. Harvey of John E. Harms Jr. & Associates Inc., secretary, and Ronald G. Lepson of Spotts, Stevens & McCoy Inc., treasurer.

Allen D. Anderson has been named executive director of the D.C. Lung Association. Anderson was formerly executive director of the Heimlich Institute at Xavier University in Cincinnati.

Ellen B. Brown has been appointed regulatory affairs attorney of the U.S. Chamber of Commerce business and government affairs department. Brown was formerly special counsel for regulatory affairs of Associated Builders and Contractors Inc.

Robert J. Milko has been named manager of information and public relations of NAVA, the International Communications Industries Association Milko was formerly director of development and communications for the American Lung Association of Northern Virginia.

Donald W. Rizzo has been elected president of the greater Washington D.C. chapter of the American Society of Chartered Life Underwriters.