Untreated Sewage

Description

 

Sewage refers to liquid wastes containing a mixture of human feces and wastewater from non-industrial human activities such as bathing, washing, and cleaning. In many poor areas of the world, sewage is dumped into local waterways, in the absence of practical alternatives.

 

Untreated sewage poses a major risk to human health since it contains waterborne pathogens that can cause serious human illness. Untreated sewage also destroys aquatic ecosystems, threatening human livelihoods, when the associated biological oxygen demand and nutrient loading deplete oxygen in the water to levels too low to sustain life.

 

Context

 

The World Health Organization (WHO) estimates that 2.6 billion people lacked access to improved sanitation facilities in 2008, with the lowest coverage in sub-Saharan Africa (37%), Southern Asia (38%), and Eastern Asia (45%).1 Improved sanitation facilities are those that eliminate human contact with fecal material and include flush or pit toilets/latrines and composting toilets.2 Even where water based toilets are available, the wastes are far too often just discharged into drains and streams, in the absence of (expensive) collection and treatment systems. As a result, surface waters in many urban areas are highly contaminated with human waste. In areas with pit latrines, seepage into local groundwater is often a major problem, since many communities rely on shallow wells for drinking water.

 

Lack of access to improved sanitation disproportionately affects poor communities in urban and rural areas where resources for investments in collection and treatment infrastructure are scarce, although the challenge of maintaining existing systems to protect humans from waterborne disease outbreaks affects even the world’s richest communities.

 

Exposure Pathways

 

Sewage can be intentionally discharged to waterways through pipes or open defecation, or unintentionally during rainfall events. When humans use these waterways for drinking, bathing or washing, they are exposed to the associated pathogens, many of which can live for extended periods of time in aquatic environments. Humans then become ill by ingesting contaminated water, by getting it on/in skin, eyes or ears, or even from preparing foods with contaminated water. Sometimes humans can even become ill from inhaling contaminated water droplets.

 

Health Effects

 

Life-threatening human pathogens carried by sewage include cholera, typhoid and dysentery. Other diseases resulting from sewage contamination of water include schistosomiasis, hepatitis A, intestinal nematode infections, and numerous others. WHO estimates that 1.5 million preventable deaths per year result from unsafe water, inadequate sanitation or hygiene.3 These deaths are mostly young children. Another 860,000 children less than five years old are estimated to die annually as a direct or indirect result of the underweight or malnutrition associated with repeated diarrheal or intestinal nematode infections .4

 

What is Being Done

 

Strides are being made on a global scale. The WHO estimated that 3.8 billion people had access to improved sanitation as of 2004, and has set a target of at least 75% global coverage by 2015. Meeting this ambitious target will be a challenge. However, a number of interventions have already proven effective in reducing the diarrheal disease burden resulting from inadequate sanitation.5 These range from hand washing and hygiene education, to toilet/latrine installation and point-of-use water treatment, to approaches comprised of multiple strategies.

 

  1. World Health Organization (WHO). 2008. "International Year of Sanitation 2008" Last accessedon September 16, 2008. Available at http://www.who.int/water_sanitation_health/hygiene/iys/about/en/index.html.
  2. WHO and United Nations Children’s Fund Joint Monitoring Programme for Water Supply andSanitation (JMP). 2008. Progress on Drinking Water and Sanitation: Special Focus on Sanitation.UNICEF, New York and WHO, Geneva, Last accessed September 16, 2008.Available at http://www.who.int/water_sanitation_health/monitoring/jmp2008.pdf.
  3. Prüss-Üstün A, Bos R, Gore F, Bartram J. 2008. Safer water, better health: costs, benefitsand sustainability of interventions to protect and promote health. Geneva: World Health Organization[Available: http://www.who.int/quantifying_ehimpacts/publications/saferwater/en/index.html, accessed 9/15/08].
  4. Prüss-Üstün A, Bos R, Gore F, Bartram J. 2008. Safer water, better health: costs, benefitsand sustainability of interventions to protect and promote health. Geneva: World Health Organization[Available: http://www.who.int/quantifying_ehimpacts/publications/saferwater/en/index.html, accessed 9/15/08].
  5. Fewtrell L, Kaufmann RB, Kay D, Enanoria W, Haller L, Colford JM Jr. 2005. Water, sanitation,and hygiene interventions to reduce diarrhoea in less developed countries: a systematic reviewand metaanalysis. The Lancet Infectious Diseases, 5(1):42-52.

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Environmental Reports

 

Since 2007, the yearly environmental toxin reports published by Green Cross Switzerland and the Blacksmith Institute have been instrumental in increasing public understanding of the health impacts of toxic pollutants and their sources.

 

The Environmental Toxin Report 2012 describes known environmental toxins and points to their industrial applications and most frequent health effects. In addition, the Report identifies the ten most important sources of environmental toxins and quantifies, for the first time, the global scale of health damage due to toxic substances. It also shows that the health impacts of industrial pollutants measured are roughly equal to those of the three major global infectious diseases AIDS, tuberculosis and malaria.

 

The Environmental Toxin Report 2011 is based on the estimated number of people affected by the sources of pollution, as well as the number of locations, identified worldwide, where environmental toxins occur in concentrations that are detrimental to health. Reports on the ten most dangerous sources of environmental toxins and the worst pollution problems were issued in the years 2008 and 2010. The environmental report published in 2009 contains case studies concerning successful remediation projects.

Donor account Green Cross Switzerland: PC 80-576-7 IBAN CH02 0900 0000 8000 0576 7