Caught in the chaos of west Beirut a single orphanage struggles to aid city's newly orphaned children

There may now be almost as many orphans as PLO guerrillas trapped in this capital city.

In the chaos of besieged west Beirut, only one orphanage still is functioning. Mohammed Barakat, director of the Islamic Home for Orphans, says the other eight such institutions have been destroyed by Israeli shells and bombs.

''We made a survey two days ago; there are 6,000 orphans in a very, very miserable condition. . . . They need water, food, doctors,'' he said Aug. 2 in his darkened office just off Corniche Mazraa, a frequent target of Israeli bombardment.

Amid the rubble of this city, it is impossible to confirm this estimate of the numbers. It is not even clear exactly how many fighters of the Palestine Liberation Organization are embattled here - probably between 5,000 and 9,000.

Some of the children may be separated from their families rather than orphaned. Yet Mr. Barakat assumes most of the parents have been killed since none have turned up during ceasefires to find their sons and daughters.

''Our orphanages in Aramoun (10 miles south of Beirut) and Ouzai (a southern suburb of Beirut) were bombed by the Israelis,'' he adds. In the orphanage's entrance hall is the casing from an American-made cluster bomb which he says plowed into the Aramoun home of 650 children.

On July 31, Mr. Barakat received assurances from the International Red Cross that this last refuge - clearly marked by a red cross on the roof - would be spared. The next day the six-building complex took three direct hits, the orphanage director says. One rocket, packed with phosphorous, which spreads out to start fires on impact, jetted in through a window, smashing into a classroom.

The Israeli Army says there are two reasons why the orphanage might have been hit. Either the PLO had a firing position near the building or the PLO shelled it. However, the shell is said to have come from the direction of Israeli artillery and the PLO has no phosphorous shells.

The Islamic Home is caring for only 600 of those estimated 6,000 children in west Beirut whose parents have been killed or have disappeared during the siege of the city. According to Mr. Barakat, the rest are scattered around the city in various shelters and refugee centers.

''We have staff who try to take care of them, or other families in the shelters do,'' the director says. ''Many of them keep asking for their parents.''

The continued bombardment makes it impossible to provide proper care or find relatives, he goes on. As he speaks, artillery exchanges just a few blocks south of the home boom louder and closer. Without a word from the staff tending them, some 40 two- and three-year-olds stream downstairs from their first-floor bedrooms.

''See, they know. They don't even have to be told to come down now,'' comments the director.

One of his assistants, crunching through the shattered glass between buildings, simply shakes his head at the rumble. A ninth cease-fire is supposed to be in effect.

''They both cheat,'' sighs the assistant.

The children have no vegetables, no fruit, sleep on the floor, and drink boiled well water. The youngest child is a 10-day-old baby girl named Salam or ''peace'' in Arabic.

The youngsters shower once every three days.

''We use our little generator fuel left to pump up water for drinking,'' Barakat explains. ''But we must keep them clean. . . They also need sun. They need to move outside. They can't stay six weeks in dark places.''

The Israelis cut electricity supplies to west Beirut eight days ago. The water supply also is often cut off.

Barakat says his buildings were not built with bomb shelters. But there is no other place to go. ''No one is safe now here in Beirut. Here we are not protected.''

He is afraid this last remaining orphanage will also be destroyed. Built 65 years ago, it is located not only in a Palestinian neighborhood but also close to the line separating east and west Beirut.

It is on the ''front line.'' Just around the corner is the Makassed charity hospital, which has also been hit.

''What we are hoping now is that this area is so deserted that there will be no reason for them to attack us any more,'' Barakat says. The Israelis, he adds, call their operation in Lebanon ''Peace for Galilee.'' But this 'Peace for Galilee' ''is hell for the Lebanese people.''