Launched today by IBGE, the Sanitation Atlas unveils maps of the spatial diffusion of sanitation networks along the Brazilian territory. For the first time data are obtained from river basins, which are considered strategic territorial units of environmental management by the Federal Law on Water Resources (Law 9433, 1997). The Sanitation Atlas presents the outcomes of the 2000 National Survey of Basic Sanitation (PNSB) in the form of maps, pinpointing, for example, water supply, sewage, waste collection and urban sanitation networks in the majority of the Brazilian municipalities. In addition, the atlas examines the distribution of these networks along river basins, showing sewage as one of the major sources of pollution in the springs of water.

Considered a public good, which should be managed in a decentralized and participatory way, water is the core of the Sanitation Atlas, launched on the World Water Day by the President of IBGE, Eduardo Pereira Nunes, and by the Director of Geosciences, Guido Gelli. The publication innovates by approaching sanitation issues from the perspective of the Brazilian territory as large river basins, strategic territorial units for planning the use of natural resources in Brazil. The Sanitation Atlas organizes the maps in six themes: spatial distribution and scope of the sanitation networks; quality and efficiency of the sanitation networks; sanitation and environment; management of sanitation services; basic sanitation according to river basins; and access to water and sewage networks in the intra-urban space (Rio de Janeiro, Brasília, Salvador, Belém and Porto Alegre).

Inequalities in the spatial diffusion of the sanitation networks become evident when viewed in maps. While water supply, waste collection and urban sanitation are available in the majority of the Brazilian municipalities, the sewage system is spatially concentrated in the Southeast region and in the most urbanized areas of Brazil. It is well known that water supply is an essential good, due to the risks its lack or inappropriate supply represent to public health. Nevertheless, sewage also represents a major problem.

Taking into account the estimates of average production of sewage per inhabitant from the National Survey of Basic Sanitation, it can be seen that the volume of sewage collected in the majority of the river basins is much lower than that produced in the neighboring municipalities. The highest percentage of districts that collect sewage are located in the coastal basins of the Southeast (95%) and in São Francisco and Prata river basins (both with 63%), followed by the coastal basins of the eastern Northeast (57%) and of the South Region (49%). The other basins registered a percentage of 20% or less. The situation is even worse if it is considered that less than 50% of the sewage collected in larger river basins is treated.

In 2000, 116 Brazilian municipalities were not serviced by the public water supply system (2% of the municipalities), most of them located in the North and Northeast regions. Although the number of un-serviced municipalities has been reducing in these regions since 1989, their proportional weight increased in 2000: it changed from 50% to 56% in the Northeast and from 21.7% to 23.3% in the North Region, indicating that the expansion of the public water system was smaller than that of other regions. These un-serviced municipalities alternatively used fountains, springs, private wells and water tanker trucks, as well as watercourses directly.

Mining, agrochemicals and sewage affect springs of water in a number of river basins

The individual analysis of each river basin allows the holistic assessment of the impact of human actions on the environment and the consequences on the quality of the springs. Sewage is one of their main polluters, notwithstanding a number of river basins are polluted in the surface water catchment related to the major economic activities nearby.

For example, mining activity is an important polluter in the Amazon basin, yet the springs are also affected by the precarious sewage network in that area, in which only 7% of the municipalities collect and treat sewage. On the other hand, the sub-basins of the Tocantins and Araguaia rivers in central Brazil and most of the coastal basins of eastern Northeast are mainly polluted by agrochemicals. Nevertheless, industrial discharges are relatively bigger in the coastal basins of the South and Southeast, even though sewage is the main pollution source in the Southeast basins.

Public health, waste and urban drainage are interconnected

In order to emphasize the relation between sanitation and human health, the Sanitation Atlas presents the spatial distribution of a number of waterborne diseases, as well as examples of different types of relationship between environment, diseases and sanitation. As the majority of diarrheas, hepatitis A and typhoid fever are diseases contracted through the consumption of water contaminated by human waste. Thus, these diseases are related to sewage and water supply distribution and treatment. Due to the strong relationship with sanitation (water quality and destination of human waste) and to the significant number of incidences, this map shows also the number of deaths and the proportion in the age groups more susceptible to fatal diarrheas derived from the environmental contamination, which are those under five and over 80 years of age.

Some diseases are related to sewage, as well as to floods and to waste collection and destination. This is the case of leptospirosis, mainly transmitted via the contact with water contaminated by rat urine. As such, the map also shows the number of incidences and deaths by leptospirosis, relating them to waste destination and floods. It is a well-known fact that the accumulation and inappropriate destination of waste usually cause an increase in the rat population, while inundations and floods increase the contact of persons with water contaminated by rat urine, potentializing the transmission of this disease.

To avoid floods and inundations in large cities, drainage systems have become a key issue in the urban planning agenda. Only 7.5% of the Brazilian municipalities use water reservoirs, one of the best options to mitigate the problems caused by urbanization. Soil sealing prevents the infiltration of rain water, causing pooling, inundation, erosion and siltation. The proportion of municipalities in the Central-West, South and Southeast Regions that use water reservoirs is higher than that of Brazil. Permanent watercourses (lakes, rivers, streams, creeks and brooklets) are the preferred targets for pouring rain water used in 75.7% of the Brazilian municipalities.