Environmental pollution burden of disease 




Despite the major efforts that have been made over recent years to clean up the environment, pollution remains a major problem and poses continuing risks to health. The problems are undoubtedly the greatest in the developing world, 

 Where traditional sources of pollution such as industrial emissions, poor sanitation, inadequate waste management, contaminated water supplies and exposures to indoor air pollution from biomass fuels affect large numbers of people. 


 Even in developed countries, however, environmental pollution persists, most especially amongst poorer sectors of society1,2. In recent decades, too, a wide range of modern pollutants have emerged—not least, those associated with road traffic and the use of modern chemicals in the home, in food, for water treatment, and for pest control. 

The progressively larger number of people exposed to environmental pollution (if only as a result of growing population numbers and increasing urbanization) nevertheless means that even small increases in relative risk can add up to major public health concerns.

 The emergence of new sources of exposure and new risk factors, some of them—such as endocrine disruptors—with the capacity to have lifelong implications for health, also means that there is a continuing need for both vigilance and action.

Links between environmental pollution and health

Environmental pollution can be simple, if somewhat generic, defined as the presence in the environment of an agent which is potentially damaging to either the environment or human health. As such, pollutants take many forms. They include not only chemicals but also organisms and biological materials, as well as energy in its various forms (e.g. noise, radiation, heat).

The number of potential pollutants is therefore essentially countless. any one of which may be released into the environment during processing or use. Fewer than 1% of these have been subject to a detailed assessment in terms of their toxicity and health risks4. The number of biological pollutants is truly unquantifiable. 
 

  Effect chain

The link between pollution and health is both a complex and contingent process. For pollutants to have an effect on health, susceptible individuals must receive doses of the pollutant, or its decomposition products, sufficient to trigger detectable symptoms. For this to occur, these individuals must have been exposed to the pollutant, often over relatively long periods of time or on repeated occasions

The whole process can simply be represented as a causal chain, from source to effect. As this indicates, most pollutants are of human origin. They derive from human activities such as industry, energy production and use, transport, domestic activities, waste disposal, agriculture, and recreation. In some cases,

Atmospheric emissions

missions to the atmosphere tend to be more closely modeled and measured, and more generally reported, than those to other media, partly because of their greater importance for environmental pollution and health (emissions to the atmosphere tend to be more readily discernible and to spread more widely through the environment), and partly because of the existence of better established policy and regulation. 

  Main sources of emissions of selected pollutants in the European Union. As this shows, combustion represents one of the most important emission processes for many pollutants, not only from industrial sources, but also from low-level sources such as motorized vehicles and domestic chimneys, as well as indoor sources such as heating and cooking in the home or workplace.

 Emissions from industrial combustion or waste incineration tend to be released from relatively tall stacks, and often at high temperature, with the result that they are dispersed widely within the atmosphere. Emissions from low-level sources such as road vehicles and low-temperature combustion sources such as domestic heating, in contrast, tend to be much less widely dispersed

Emissions to surface water, groundwater, and soil

Releases to other media, such as surface waters, groundwaters and soil, also occur through a range of processes. Deliberate discharge, spillage (e.g. from storage, during transport, or during processing and usage), leakage and runoff (e.g. of agricultural chemicals) are all important in terms of aqueous pollutants.


 Legal limits for discharges to streams are set for many industries, aimed at keeping levels of contamination within acceptable limits. Illegal discharges, or accidental spillage, however, sometimes occur and accounted for the majority of reported surface water pollution 

Environmental fate

Once released into the environment, pollutants may be transported via many different processes and pathways, often moving from one medium to another, and undergoing a wide range of modifications in the process. Chemical reactions, physical abrasion, sorting by size or mass and deposition all change the composition of the pollutants and alter the pollution mix