Dart Drug Corp. yesterday reported lower profits for the quarter and nine months ended Dec. 31, despite a significant increase in sales volume.

President Herbert H. Haft attributed the decline in profitability for the recent quarter to generally soft retail sales here and a decision by Dart management to cut prices in order to maintain volume.

Third-quarter profits were $475,000 (26 cents a share) compared with $637,000 (34 cents) in the same period of 1975 as sales jumped 21 per cent to $47.5 million.

For the first nine months of Dart's fiscal year, profits totaled $1.38 million (75 cents a share) compared with operating profits in the year-earlier period of $1.41 million (76 cents). In the nine months ended Dec. 31, 1975, Dart also had a $72,000 tax benefit and a $100,000 deduction for an accounting change which produced net income of $1.38 million (74 cents).

Nine-month sales rose to $129 million from $109 million in the 1975 period. Dart opened its 71st store during the recent quarter, in Salisbury, and plans eight new stores in the coming year. The chain plans to open four new optical departments this year, in addition to five already opened.

Haft said company officers have projected sales in the year ended March 31 of about $170 million.

American Realty Trust, an Arlington real estate investment trust, yesterday reported profits of $207,561 (9 cents) for the quarter ended Dec. 31, compared with a loss in the same period of 1975 that totaled $516,956. Revenues rose from $1.39 million to $2.05 million.

All profits in the recent quarter reflected $643,775 from recovery of bad debts, however, which covered a net loss from operations of $435,214. ART said it failed to make a sinking fund payment due Dec. 31 on debentures. Of $300,000 required, $54,000 has been paid and the trust said it expects to pay the balance in several weeks, resolving a default.

A statement from ART said it "hoped" a recent trend of recovery would continue in coming months.

Best Products Co., a Richmond-based catalog retailer, reported profits of $11.8 million ($2.03 a share) in the second quarter ended Jan. 1 compared with $6.5 million ($1.13) a year earlier. Sales rose to $198 million from $142 million.

Much of the gain was attributed to the opening of five new merchandise showrooms. For the six-month period, profits totaled $13.8 million ($2.39) on sales of $7.8 million ($1.35) and sales of $189 million.

Despite recent cold weather, sales in the first five weeks of the current quarter were up 21 per cent, Best said.

Wapora, Inc an environmental consulting company, reported profits of $44,158 (17 cents) in the second quarter ended Dec. 31 compared with $36,952 (6 cents) a year earlier. Sales rose to $1.06 million from $769,000. For the recent six months, Wapora profits fell to $47,309 (8 cents) from $82,708 (14 cents) and sales rose to $2 million from $1.6 million.

President J. I Bregman said revenues have turned sharply upwards in the three recent quarters, mainly from new industrial and government contracts.