Because monitoring is often divided among various agencies, none has overall responsibility for coordinating the results or setting standards to cover all the routes of intake (air, water, food, tobacco, occupational exposure, etc) of toxic substances into the body. Only rarely are standards based on local conditions of exposure backed up by the biological monitoring of tissue and epidemiological surveillance. Indeed, the trend is to rely on multinational standards or guidelines, employing a safety factor to cover local variations. Standards for lead in water, air, petrol, paint and food, for example, are the responsibility of up to five different agencies, each of which may monitor its own medium, while the monitoring of soil around the home - a major source of intake by smaller children - may be no one's responsibility. Many other examples of divided responsibility can be found. The reasons for dispersed authority lie in the legislative history of the countries surveyed. Agencies and ministries have been set up over the years on an [ad hoc] basis to deal with water, food, industrial resources, occupational exposure, etc, as each one came to be seen as a problem. The responsibility for monitoring was frequently assigned to an existing body that was already dealing with supply or distribution, sometimes with the requirement that the health aspects be coordinated with the ministry responsible for public health. Even when several agencies have been combined under one ministry responsible for the environment, certain strongly entrenched departments have successfully resisted efforts to transfer their activities to that authority. In fact, a division of responsibility may exist even within a ministry if it is organized with separate departments for air, water supply, waste disposal, etc.
In countries where development is at a relatively low level and where the problems of the human environment are closely linked to poverty and to the very lack of development itself, human health and life are continually jeopardized by biological pollution resulting from insanitary conditions, both in congested urban areas and in rural areas. The absence of safe water supplies and of facilities for the sanitary collection and disposal of human excreta, refuse and industrial waste, and the prevalence of vectors of disease, with the consequent high incidence of sickness from communicable diseases, are still the prime environmental problems in these developing countries.