NEW YORK, OCT. 5 -- Stocks closed narrowly lower today in moderate trading as investors took profits from last week's strong gains.

The Dow Jones industrial average eased 0.81 to 2640.18, after being off by as much as 15 points during the day.

Declines narrowly outpaced advances.

Broad-market indexes posted narrow gains. The New York Stock Exchange composite index edged up 0.01 to 183.44. Standard & Poor's 500-stock index added 0.01 to 328.08. The price of an average share was unchanged.

Big Board volume was 159.6 million shares, compared with 189.6 million Friday.

"It was just a normal setback from the good action last week," said Rodd Anderson, vice president in Shearson Lehman Bros. Inc.'s equity trading department.

On the Big Board, Hanson Trust was the most active NYSE-listed issue, up 3/8 to 15 1/2. Tenneco followed, up 2 1/8 to 59 7/8, and National Semiconductor was third, up 3/4 to 21 7/8.

Union Carbide rose 1 3/8 to 32 after the Supreme Court left intact lower-court rulings that hundreds of lawsuits relating to the 1984 disaster in Bhopal, India, should be tried in India.

Among other blue chips, AT&T was off 5/8 to 33 1/2, General Electric gained 1/4 to 62 5/8, General Motors dropped 1 1/8 to 81 5/8, USX rose 1/8 to 38 3/8 and Eastman Kodak was off 3/4 to 104 1/8.

Zayre gained 2 1/2 to 34 3/4 after it said investor Edward DeBartolo Jr. revealed that a group he leads has acquired more than $15 million worth of Zayre stock.

High-technology and semiconductor issues were mixed. IBM gained 1 1/4 to 156 1/2, Advanced Micro Devices was unchanged at 24 5/8, Compaq Computer was up 1 3/4 to 78 1/4, Hewlett-Packard was up 7/8 to 73 1/2, Motorola was off 1/4 to 72 3/4 and Texas Instruments gained 3/4 to 79 3/8.

Oil stocks were mixed. Exxon was unchanged at 49 3/4, Mobil was up 3/4 to 50 7/8, Chevron was off 1/8 to 55 1/2, Phillips Petroleum was off 1/8 to 16 3/4 and Royal Dutch was up 3/4 to 130 3/4.

Nationwide turnover in NYSE-listed issues, including trades in stocks on regional exchanges and over the counter, totaled 185.7 million, compared with 220.5 million on Friday.

Prices were narrowly lower in moderate trading of American Stock Exchange issues.

Wang Laboratories class B led the Amex actives, up 3/4 to 19 1/8. It was followed by Home Shopping Network, off 1 to 12 7/8, and Western Digital, up 1 1/8 to 26 1/2.

The American Stock Exchange index fell 0.04 to 359.33. The price of an average share was unchanged. Declines outnumbered advances 340-277 among the 883 issues traded. Composite volume was 12.2 million shares, compared with 13.3 million Friday.