Ousted Environmental Protection Agency official Rita M. Lavelle held lunch and dinner meetings throughout 1982 with executives of companies under investigation by the hazardous-waste program she directed, according to an appointments calendar kept by her personal secretary.

Lavelle, who was fired last week by President Reagan at the request of EPA Administrator Anne M. Gorsuch, met at least 14 times last year with Charles L. Sercu, an employe of Dow Chemical Co., which deposited poisonous chemicals in at least one hazardous-waste dump ranked by EPA among the most dangerous in the country.

The meetings with Sercu were almost always over lunch or dinner, according to the calendar, which was delivered yesterday by Lavelle's lawyer to the Senate Environment and Public Works Committee and was made available to reporters.

It shows that Lavelle dined with Sercu, who also works for the Chemical Manufacturers Association, and a representative of Stauffer Chemical Co. Inc. on the night before EPA entered into an agreement requiring Stauffer to clean up a hazardous-waste site in Woburn, Mass.

The calendar also is punctuated with lunches, dinners and office meetings with representatives from Aerojet General Corp. (Lavelle's former employer), Monsanto Chemical Corp. and many other firms that EPA officials said may be held liable under the program Lavelle directed for cleanup of the nation's dangerous dumps.

Six congressional subcommittees are investigating charges that Lavelle and other EPA officials negotiated "sweetheart deals" with firms rather than forcing them to pay their share for cleaning up the sites, which are considered serious threats to public health and safety.

The steady diet of industry contacts documented in Lavelle's calendar appeared certain to fuel charges by congressional critics that she was too close to firms that generate hazardous wastes to enforce regulations against them. But it was not immediately clear whether any of the contacts constituted official misconduct.

No meetings with environmentalists could be found in the date book, which shows that Lavelle attended at least three sessions at the White House, including a Sept. 20 meeting with Gorsuch and presidential counselor Edwin Meese III, who held the Bible at Lavelle's swearing-in ceremony but has said he does not know her well. A July 19 session with Meese aide Craig L. Fuller was labeled "EPA successes."

The House and Senate panels are also investigating charges of political favoritism and mismanagement in Superfund, the $1.6 billion hazardous-waste cleanup program.

Lavelle has emphatically denied all accusations of wrongdoing.

Meanwhile, Justice Department officials said they have begun inquiries into five points of possible misconduct by Lavelle that were brought to their attention in letters from Gorsuch in the days before and after Lavelle's dismissal.

Gorsuch's letters to Deputy Attorney General Edward C. Schmults do not accuse Lavelle of violating any laws. But they ask Justice to "review" her relationship with companies that dumped poisonous chemicals at two of the most dangerous waste sites and to probe possible obstruction of congressional investigations into her program.

The companies include Lavelle's former employer, Aerojet, which deposited waste at the Stringfellow Acid Pits in Riverside, Calif., and which may be forced by the EPA to help pay for cleanup of the dump. Lavelle has said she removed herself from the case, but congressional subcommittees are investigating charges that she influenced decisions that could reduce Aerojet's liability.

Also included are Outboard Marine Corp. and Monsanto. An internal EPA memo found in Lavelle's personal computer shortly before her firing said she told officials of the two firms last November "that EPA might seriously consider a new settlement offer" in a second hazardous-waste case over contamination of the Waukegan, Ill., harbor.

A month earlier, a federal judge had refused to dismiss an EPA civil suit against Outboard Marine that could result in payment by the firm of up to $40 million to clear the harbor of highly toxic polychlorinated biphenyls (PCBs), which were produced by Monsanto and discharged by the outboard motor company.

Soon after the meeting with Lavelle, attorneys for the two firms arranged a meeting with government lawyers and made what EPA officials considered an inadequate offer to settle the suit, according to administration officials.

The letter from Gorsuch asks Justice to determine whether Lavelle's meeting with officials of the firms constituted an improper "ex-parte" contact, as Outboard Marine was and still is a defendant in an EPA enforcement action.

The letters also asked Justice to review charges by House subcommittees that Lavelle gave false testimony about a "whistle blower" on her staff and that she or her aides obstructed congressional panels by shredding documents and removing others from EPA offices.

Lavelle's lawyer, James J. Bierbower, said he did not know of Gorsuch's flurry of referrals to Justice. They constitute the first such action by Gorsuch against a subordinate, according to a Reagan administration official, who noted that Congress has accused other Gorsuch aides of conflicts of interest.

"We didn't know about any of these referrals," Bierbower said. "But as always, we welcome any investigation of the facts. We have nothing to hide."

Congressional investigators closed in on Lavelle and her former associates yesterday. The Public Works and Transportation Committee and the oversight subcommittee of the House Energy and Commerce Committee both tried to serve subpoenas on her for hearings today. Three House subcommittees asked for her appointments calendars.

Bierbower delivered the calendars to the Senate committee yesterday morning, and the committee staff supplied dozens of copies to House investigators and reporters.

Gorsuch wrote the first letter to Justice on Feb. 2, two days before she asked Lavelle to resign, and the second on Feb. 8, the day after Lavelle was formally fired by Reagan.

A Justice Department official, acknowledging that the agency had begun a review of the letters, said: "There was an awful lot of reluctance for us to be involved."