Several West German state governments rely on a common yet effective device to help them protect the environment. The device is the telephone.

As the system currently works, citizens are invited to dial a special number and complain about air pollution, noise, garbage collection, sewage difficulties, littering or any other environment problem that troubles them, and specila officials at the other end of the line examine the report.

Thus the so-called "ombudsman" approach, which originated in Scandinavia to deal with citzen complaints of various kinds has been adapted here to environmental issues with considerable success.

The idea of an environmental "hot line" was conceived and put into operation two years ago in the West German state of Baden-Wuerttemberg, and it has since been adopted in Bavaria as well as in the cities of Hamburg, Bremen and Berlin.

According to the Baden-Wuerttemberg authorities, 3,000 calls have been recorded since the system went into effect, and more than 80 per cent of the problems raised have been resolved.

A recent study of the complaints registered indicates that more than half focused either on air pollution and noise, and the rest ranged from garbage disposal to defacement of the landscape.

As the system functions in Baden-Wuerttemberg, citizens dial a number in the city of Stuttgart, and are connected with an official of the state Ministry of Nutrition, Agriculture and Environment whose only job is to deal with grievances. The official notes the complaint and, promising to report back to the citizen, passes it on to the proper department.

With the growth of complex bureaucracies, finding the proper department for each complaint is not always easy. For example, a complaint about street noise might go to different departments, depending on the cause of the niose.

The civil engineering office would be alerted if the noise stemmed from bad street conditions. The industrail inspection board would be called if the noise came from trucks, and the traffic department would be consulted if heavy traffic were the cause of the disturbance.

SINCE THE average citizen is usually unable to locate the exact bureaucrat to handle his problem, it is the role of the environmental official to pinpoint the right place for the complaint - and, moreover, to demand action. As the statistics show, the proportion of corrective action has been high.

Consider, for instance, the case of a citizen in the Boblingen district of Baden-Wuerttemberg. He complained that smoke from two furniture factories in his neighborhood was giving him nausea, stomach trouble and conjuctivitis, and he alleged that plastics were being burned by the plants.

The matter was referred to the industrial inspection board, which found after investigation that both factories complied with environmental regulations. Nevertheless, one of the plants installed an additional mechanism to filter its smoke, and the complaining citizen was advised that "something" had been done.

In another case, a club of anglers on Lake Constance reported a high incidence of fish mortality, suggesting that the cause might be toxic sewage from a nearby factory. The case was brought to the attention of a state chemical testing station, which analyzed water samples, discovered that the factory was indeed polluting the lake, and compelled its directors to take decontamination measures.

One of the most significant cases to result from the environmental "hot line" involved a soap factory situated near the Black Forest that exuded unbearable odors. After an investigation, the authorities ordered the plant closed, and despite a long court battle, the factory was shut down.

This case undelines the obvious fact that the "hot line" is only a single step in the effort to protect the enviroment here, and its effectiveness ultimately depends on tough laws and the willingness to enforce them.

Despite the success of the environmental telephone in the few places it is operating at present, government officials in several other parts of West Germany show little enthusiasm for it. They contend that complaints will reach the proper departments through ordinary channels.

this reluctance to adopt the system may reflect a valid fear that officials assigned to the telephone may be besieged by angry complaints against barking dogs, lively parties and the din of teenagers playing rock music.

But where the "hot line" is operating, it may be doing more than helping the government to clean up the environment. It may also be sharpening the consciousness of citizens by reminding them that they have a direct voice in their own affiars - and that could be as healthy as smokeless factory chimneys and unlittered parks.