2.7 Major health risks associated with environmental pollution

So far you have learned how different categories of waste (solid waste, liquid waste including human excreta, and air pollutants) pollute the environment and can have a serious effect on human health. Table 2.1 summarises the major health problems associated with wastes and pollution.

Table 2.1 Summary of major pollutants and associated health risks.
ContaminationWaste categoryRelated health problems
Bacteria, protozoa, viruses and parasites such as intestinal wormsHuman excretaAcute watery diarrhoea (AWD), dysentery, cholera, typhoid fever, ascariasis, schistosomiasis, polio, and intestinal infections caused by roundworm, whipworm and hookworm
Heavy/toxic metals

Industrial wastes


Continued and long-term ingestion of heavy metals can cause cancer and have direct toxic effects
Smoke (very small airborne solid particles)

Vehicle emissions

Domestic fires

Industrial emissions

Respiratory infections, pneumonia, in severe cases lung cancer can occur
Carbon monoxideVehicle emissionsCan cause acute respiratory problems and death
VirusesMedical wastes containing body fluids from patients

HIV/AIDS infections


Of all the health risks identified in Table 2.1, the problem of contamination with human excreta has the greatest impact. Globally, diarrhoea is the second most common cause of death in children under five years of age (Walker et al., 2013, cited in Brown et al., 2013). Worldwide, 807 million people are infected with the Ascaris worm that causes ascariasis (Hotez et al., 2008, cited in Brown et al., 2013).

It is clear that there is a significant disease burden on urban communities because waste is not efficiently managed. Access to proper latrines is one crucial area of WASH service that can help to reduce or eliminate the major health risks related to faeces given in Table 2.1. Solid waste collection, transport and disposal are essential areas of service. Pit emptying, which ensures faecal sludge is collected and disposed of safely, is particularly important to minimise the health risks to local communities. The government of Ethiopia is therefore putting considerable emphasis on working to improve these particular WASH services in urban areas.

  • List the major health risks associated with poor access to, or improper use of, latrine facilities.

  • The major health risks are waterborne diseases related to faeces such as acute watery diarrhoea, dysentery, ascariasis, cholera, typhoid fever and intestinal worm infection.

These health risks do not affect everyone in the same way. Certain segments of urban communities are more vulnerable to the effects of environmental pollution than others.

  • Which groups of people were identified in Study Session 1 as being particularly vulnerable in urban communities?

  • Young children, the elderly, people with disabilities, people living with HIV/AIDS or infected by other diseases, and poor families are the main vulnerable groups.

Exposing these vulnerable people to an additional disease burden can significantly affect their health status. For example, if people already living with HIV/AIDS are infected by diarrhoea, their lives can be threatened, which can have serious implications for those providing care and support, as well as having a substantial economic impact on the families involved.

Poor people are a particularly vulnerable group. They are likely to live near waste dumpsites because they cannot afford to live in areas where there is a proper infrastructure. They may be the first people to be exposed to the effects of accumulated waste. They are also the most likely people to be hired to work in the collection and transportation of waste, but because proper protective clothing and equipment are often lacking, they are exposed to infection as they go about their daily work. Some in extreme poverty, commonly called rag pickers (or korales), try to survive by collecting reusable waste. Their health is at continuous risk due to their constant exposure to wastes.

When disease affects those in vulnerable groups, it may spread to the entire urban community. For WASH services to be effective they need to be designed and implemented to reach everywhere and everyone.

  • List some of the poor environmental practices seen in urban communities. Explain the relationship between these practices and the health problems they may cause.

  • Poor environmental practices include:

    • throwing faeces away in plastic bags
    • open defecation
    • inappropriate construction of pit latrines
    • dumping solid waste without care
    • using wood or charcoal for cooking indoors.

    The first three in this list can all cause the spread of infectious diseases that are transmitted from person to person through pathogens in faeces. Dumping solid waste carelessly can create conditions that encourage breeding of disease vectors. Respiratory infection due to polluted air is another risk area, which can result from the last point.

Summary of Study Session 2