Two Washington area cooperatives are among the first in the country to be granted loans by the recently established National Consumer Cooperative Bank.

Greenbelt Cooperative and Arlington Cooperative Organization received $750,000 and $10,000 respectively. The bank today announced $10 million in loans at 16.5 percent interest to 11 co-ops in eight states.

Greenbelt, which is celebrating its 40th anniversary this year, will use the funds to purchase new gasoline pumps and tire machines, new refrigeration equipment and electronic cash registers. The registers will facilitate the return of earnings, prorated according to purchases, to the co-op's 11,400 members, said president Bob Satake, Greenbelt's outlets are Scan furniture stores, Exval service stations and supermarkets.

Arlington, which began in 1975 when several food-buying clubs merged, has 800 active members and weekly sales of just $1,200 to $1,400.

Forced out of its Columbia Pike location by a developer, the co-op has rented a larger place on South Edgewood Street. The borrowed money will go for moving expenses and additional inventory. As a condition of the loan, Arlington has pledged to increase its membership and sales by half, said Douglas Schiffman, a director.

Both co-ops said they had been unsuccessful in the past in obtaining loans from commercial banks. The Co-op Bank, located on S. Street NW, was authorized by Congress to fill this vacuum. It plans to lend $300 million to co-ops over the next five years.