LUANDA, ANGOLA -- On a Sunday morning in June, Goncalves Chacalaga, who is 12 years old, stepped on a glittering bit of metal. He was walking barefoot through a field of cassava near his village in northern Angola. The land mine blew away most of his left foot.

Emelia Valente, 24, mother of two from north-central Angola, watched her husband and mother die in a rebel raid in May. Two months later, fetching water for her children, she stepped on a land mine. Her second amputation -- the first had failed to stop an infection -- was performed this month in a Luanda hospital.

Flames in the night chased Antonio Calangue, now 14, out of his family's house in southeastern Angola. Rebels had attacked his hometown, Cangamba. As Antonio ran for the bush, a shell caught him high on his right thigh. That was in 1981. After six years on a waiting list, he was fitted this year with an artificial leg.

From a geopolitical perspective, Angola's civil war has something for everyone. It is fueled on one side by about $4 billion worth of weapons from the Soviet Union and on the other by at least $30 million in weapons from the United States. Cuban soldiers wait for periodic incursions of troops from South Africa. The war is a proxy for superpower rivalry and a lightning rod for black Africa's fight against the system of racial segregation called apartheid. It is a testing ground for Soviet arms, Cuban advisers and the Reagan Doctrine: American military hardware checking the spread of communism.

From a human perspective, the war is something else. It starves children and their mothers on both sides. It kills them indirectly with diarrhea, anemia and tetanus. Quite often it blows their legs off.

Relief agencies that count the victims have concluded that, as the 12-year-old war grinds on, women and children are being singled out as targets.

"More and more attacks are made especially on women and children in order to terrorize the population and create instability," says a recent U.N. Children's Fund report on Angola.

"It is to be concluded that the nutritional situation and . . . state of health . . . of severely affected persons will further deteriorate due to growing external support" to the rebels, it said.

In war-affected areas, UNICEF estimates that up to 37 percent of children die before the age of 5. A government report this month says that as many as one in 50 mothers die in childbirth. Both figures are among the highest in the world.

Antipersonnel mines believed by most observers to have been placed by antigovernment rebels have mutilated 10,000 to 15,000 women and children. Between 15,000 and 20,000 children have been orphaned or abandoned. There are 690,000 displaced people, 80 percent of whom are women and children.

The government says about half of the urban population now "faces acute shortages of staple foods." Most of these hungry city people, the government says, are children. Records at a large Luanda hospital show that admissions of children with severe malnutrition have increased twentyfold in the past five years.

Scores of government health centers have been burned down in the countryside, apparently by the rebels. At those still standing, UNICEF says health workers hardly ever show up for work and those who do have almost no drugs and no means of transporting severely ill patients to hospitals.

Since 1980, the percentage of children enrolled in school has fallen from 37 to 1.

Four out of five children in rural areas have no access to safe drinking water. As a result, 60 percent of the deaths of children under 5 are due to diarrheal disease.

There is an acute shortage of artificial legs.

The Marxist government of Angola lays the blame for all these grim indices of child welfare on rebels of the National Union for the Total Independence of Angola (UNITA) and on the governments of South Africa and the United States, which support the rebels.

For the second consecutive year, the U.S. government has sent at least $15 million in military equipment to the prowestern rebels. South Africa has backed them with arms, provisions and, on occasion, large numbers of troops.

"These dollars to UNITA help it to arm and equip itself," said Jose Antonio Martins, a senior Angolan official responsible for coordinating international emergency assistance. "UNITA massacres and kills with those arms. The money given by the United States contributes to the emergency situation in this country," he claims.State Department View

The State Department rejects this view. Support for the rebels, it maintains, is intended to pressure the Angolan government to negotiate with them. The rebel group occupies a sizable part of the country and has the support of Angola's largest tribal group, the Ovimbundu.

The State Department has suggested that the oil-rich Angolan government is shedding crocodile tears for its neediest while pouring nearly all its resources into the war.

It said Moscow has sent $4 billion worth of arms into Angola in the past decade and $1 billion in the last year alone.

"It would appear that while oil revenues have gone up in Angola in the past year, that this money is not being spent by the Angolan government to address the urgent needs of its suffering population," State Department spokesman Charles E. Redman said earlier this month.

Negotiations between Angola and the United States over the withdrawal of 37,000 Cuban troops from this country are stalled.

Assistant Secretary of State Chester A. Crocker described a meeting here last month with Angolan officials as "a waste of time." Angolan Vice Foreign Minister Venancio de Moura last week accused Washington of "clear interference in our internal affairs."

As governments exchange indignant accusations, relief organizations are discovering that more and more of Angola's women and children are caught in the war's cross fire.

To the north is a highly centralized, administratively incompetent, but well-armed Marxist government that is believed to spend at least 60 percent of its revenue on war.

To the south is a well-armed guerrilla army that western aid officials say appears increasingly willing to target civilians as a way to destabilize the government.

"There is no doubt that UNITA's policy is to terrorize civilians," said a western development specialist who has worked in the war-affected regions of southern Angola for seven years. "They want to push people off the land and make them dependent on the government, so the government will have less money to fight the war."

This view is widely shared by many western diplomats here and senior officials at U.N. relief agencies operating in Angola, although U.N. reports last year stopped short of publicly accusing UNITA of planting the mines and observers acknowledge that independent confirmation of government allegations is frequently difficult.

UNITA officials, however, have vigorously denied using violence against civilians. They accuse the government of planting the mines in disputed areas.

"Many cases have been reported to us of women and children sitting in their huts, starving, while their maize ripens in front of them," said Jean-Pierre Gerney, deputy resident representative of the U.N. Development Program here. "They have seen too many people mutilated by mines. They prefer to stay in their huts or they come into the towns looking for food."

The seeding of antipersonnel mines in fields, roads and on footpaths near rivers has helped cut Angola's food production in half in recent years.

"Nobody can be a farmer when there are mines," said Adamo Valy, food logistics coordinator for the U.N. World Food Program. "Most of the displaced are women and children because they are the main people who work in the fields.

"You cannot say that the places where these displaced are living are organized camps. They don't have tents {or} water and some of them are forced to move two or three times a year."

Most of the displaced have crowded around provincial capitals in the densely populated central plateau region. Once the breadbasket of Angola, much of this region is now depopulated except for slums encircling cities -- slums where surveys have found widespread malnutrition and frequent epidemics of water-borne diseases such as cholera.

In recent months, U.N. officials report, mines and bombs have been planted in the streets and shops of these towns, especially in Huambo, Angola's second largest city.

More than half the patients in Huambo Hospital's orthopedic wards are amputees, according to UNICEF.

While he was working in Huambo in March, Valy said, a bicycle carrying a bomb in a wicker basket was parked near a shop selling children's clothes. He said the bomb, apparently planted by UNITA, destroyed the shop and killed two women.

Those who come to town looking for help from the government find a health and social service bureaucracy that, even according to the Angolan government, is a shambles.

The most conspicuous example of government disorganization is its chronic inability to put together military convoys to escort food aid into the central highlands. U.N. relief officials said lack of military escorts, not lack of donated food, explains the current food shortage in that region.

In a document supporting Angola's largest-ever request for international emergency aid, the government admitted that it had diverted nearly all its technical and managerial resources to the war.

But part of the reason for the collapse of health care, sanitation and social services has little to do with war.

Until Angola's independence 12 years ago, most technical and managerial jobs in the country were held by Portuguese. The Portuguese had educated few Angolans during a 500-year colonial presence here, and fewer still had been taught technical skills.

The sudden departure of about 300,000 Portuguese when Angola became independent in 1975 left the new government with a highly developed colonial infrastructure that almost no one knew how to manage, operate or maintain.

Another cause of the collapse of social services, according to relief organizations, is a highly centralized and authoritarian government that does not pay civil servants enough to live on.

"Most of the health workers who are supposed to be giving shots to children are out looking for food, for cooking gas and for water," said Dr. Joyce Andrade, a Brazilian doctor in charge of UNICEF's immunization program in Angola.

Immunization programs have proved to be one of the most cost-efficient ways of improving health care in Africa. But Andrade said Angola's program is foundering, with full immunization coverage for only about 7 percent of children in Luanda and about 2 percent in provincial capitals.

"The real problem for us is how to motivate people to work. We have the drugs, the equipment, everything, but we don't have the people to give the shots," Andrade said.

Wages paid government employes are nearly worthless in Angola's barter economy. In government shops where the money can be used, food and other essentials are often not available.

"You can't really blame people for not working," said Andrade. "They are out in the streets most of the time trying to survive."

The disintegration of child and maternal health is not confined to war zones in southern Angola. Here in the northern port capital of Luanda, where there are no security problems, the government says half the population is on the verge of famine. Pediatricians said child health and nutrition have never been worse.Luanda's Slums

Before independence, Luanda was known as the Rio de Janeiro of Africa. Built on a crescent of hills overlooking a bay, it was a city of high-rise apartments, smart shops and coffee bars. Its population was about 200,000, most of them Portuguese.

Since independence, Luanda's population has swollen to an estimated 1.4 million. The first lucky settlers took over apartments in high-rises abandoned by the Portuguese. Few of these buildings now have running water above the first floor.

But most newcomers built shacks on the edge of town. There, in slums of mud brick and tin roofs, they have little access to water, sanitary facilities, electricity or food.

"There are great difficulties of treating children in the city: no communications, no system of transport, no ambulance and the midnight curfew. When we had word of cholera in the suburbs, we had to wait until morning before trying to pick the child up," Dr. Luis Bernadino, a pediatrician at Josina Machel Hospital here, said.

The May cholera epidemic has run its course, requiring the hospitalization of 800 children, Bernadino said. He said the most pressing problem in the city remains lack of food.

"There is a great rise in malnutrition in the past year. In June, for the first time, malnutrition exceeded acute respiratory failure as the leading cause of death in this hospital," he said.

The hospital is now seeing about 400 children a day for complications related to malnutrition. It admits about 22 a day for severe malnutrition.

"There is plenty of food at very high prices in the black market, but not in the government shops," Bernadino added.

Angola is a rich agricultural country, but farmers here refuse to sell their crops for Angolan money. They insist on trading for consumer goods. The poorly organized government has trouble manufacturing, importing or distributing these goods. So farmers see little point in growing more than they and their families can eat.

"It is not the war that stops agricultural production," said a western agriculture specialist who has had wide experience in Africa. "It is the system."

The food gap in Luanda has been filled in the past with food imported from Europe that was sold at subsidized prices in government shops.

Last year's collapse in oil prices cut in half Angola's ability to buy imported food, according to the appeal for food aid. A government relief official said increased revenue this year from the rebound in oil prices has not yet made up for the 1986 shortfall. The emergency appeal declares that Angola can afford to buy only one-third of the imported food it needs.

And the war drags on, with four or five land-mine-injured children trucked daily into the surgical ward at Luanda's Josina Machel Hospital for routine morning amputations.

The war drags on, as well, for children who left the hospital years ago.

Antonio Calangue, the 14-year-old crippled in a UNITA raid six years ago in southeastern Angola, has been practicing walking for 10 months with his artificial leg.

He practices at an orphanage in Luanda. The rebel raid that destroyed his leg also destroyed his family. They all ran away into the bush on the night of the raid, he says, and he has not heard from them since.