One of the most notable changes in modern times is the rapid urbanisation of our planet, which began in the 19th century. While in 1950, 29% of the global population lived in cities, that figure is estimated now at 50%, and by 2030 it will reach 61%. In Africa, urbanisation experienced a rapid shift from 15% in 1950 to 41% today. It is estimated that by 2030, 54% of the population in that continent will be living in cities. Not only are more people living in cities but the cities themselves are becoming larger and more densely populated. This situation poses unique problems related to the provision of water, sanitation and a healthy environment. Africa has now 19 cities with populations of more than one million inhabitants. Because of slow economic growth, lack of effective development policies and limited resources, the development of infrastructure has not kept up with the increasing needs for shelter and services in growing urban populations. In Egypt, it is estimated that only about half of the population is connected to sewers. In addition, drinking water quality is often below standards, since some water treatment plants are not maintained properly. As a consequence, about 17,000 children die each year because of intestinal infections. This is the case for many African cities, where local governments have been unable to keep pace with change and, as a consequence, have also been unable to provide dwellers with proper infrastructures related to the provision of water and the collection, transportation, processing and disposal of waste materials. In developing countries with economies under stress, waste management is a problem that often endangers health and the environment. In addition, this is given low priority by governments often besieged by other problems such as poverty, hunger, children's malnutrition, water shortages, unemployment and even war. Poor hygiene, inadequate management of liquid or solid waste and lack of sanitation facilities are contributing factors in the death of millions of people in the developing world due to diseases that are easily preventable. In addition, people living in un-serviced or poorly serviced areas value the increased convenience and privacy associated with improved sanitation. For example, lack of sanitation and inadequate disposal or storage of waste near houses can provide habitats for vectors responsible for several infectious diseases such as amebiasis, typhoid fever and diarrhoea. Uncontrolled and inadequate landfills are a danger to the environment and a health risk to the population since they may lead to contamination of water and soil. The health risks associated with poor sanitation tend to be higher in densely populated low-income urban areas. At a global level, more than 5 million people die each year from diseases related to inadequate waste disposal systems.
Contamination of water leads to a whole range of diarrheal diseases such as cholera, that kills 1.8 million people worldwide. An estimated 90% among them are children below five, mainly from developing countries. Most of the burden can be attributed to unsafe drinking water, inadequate sanitation and poor hygiene practices. The children that are affected the most are those living in low-income urban areas. According to UNICEF, Infant Mortality Rates (IMRs) are almost always higher in poor urban areas than the national average and than those in rural areas. A great proportion of the high mortality among the children of the urban poor can be attributed to diseases common in urban areas such as diarrhoea, tuberculosis and parasitic diseases (intestinal worms) that are frequently associated with lack of safe water and sanitation. Malnutrition in children is often a consequence and a complicating factor. Germs, particularly those present in water, food or on dirty hands are the most frequent cause of sickness worldwide. Although lack of safe water and sanitary facilities are significant problems, they are made even worse by ignorance in the general population, particularly mothers, about the connection between dirt, germs and childhood diarrhoea. Several naturally-occurring and human-made chemical substances present in drinking water can have a serious effect on health, particularly in high concentrations. Among chemicals that can be dangerous at elevated levels are fluoride, arsenic, lead, cadmium, mercury, nitrates and pesticides. All these factors stress the need to implement policies that ensure the provision of safe water to the population, particularly in marginal areas lacking basic health and social services. Africa has the lowest water supply and sanitation coverage of any other region in the world. It is estimated that one in three Africans has no access to improved water or to sanitation facilities and the number of people lacking those basic services is increasing. The majority of those lacking basic services live in informal or suburban areas and rural communities. Unless actions are taken now, the absolute number of people lacking basic services will increase from 200 million in 2000 to 400 million in 2020. Despite progress, however, many Sub-Saharan countries will find it difficult to reach the Millennium Development Goals (MDGs) set for 2015, particularly the MDG 7 which stipulates to halve, by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation. It is necessary to overcome the lack of integration between the various components of environmental sanitation: excreta, domestic and industrial waste-water, solid waste and storm water which are often run by separate agencies or institutions. Better use of synergies can lead to more sustainable and cost-effective solutions.
Dr Cesar Chelala is an international public health consultant and a winner of an Overseas Press Club of America award
