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Pathogens & Contaminants
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Copy it, adapt it, use it – but acknowledge the source!Copyright
Included in the SSWM Toolbox are materials from various organisations and sources. Those materials are open source. Following the open-source concept for capacity building and non-profit use, copying and adapting is allowed provided proper acknowledgement of the source is made (see below). The publication of these materials in the SSWM Toolbox does not alter any existing copyrights. Material published in the SSWM Toolbox for the first time follows the same open-source concept, with all rights remaining with the original authors or producing organisations.
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Disclaimer
The contents of the SSWM Toolbox reflect the opinions of the respective authors and not necessarily the official opinion of the funding or supporting partner organisations.
Depending on the initial situations and respective local circumstances, there is no guarantee that single measures described in the toolbox will make the local water and sanitation system more sustainable. The main aim of the SSWM Toolbox is to be a reference tool to provide ideas for improving the local water and sanitation situation in a sustainable manner. Results depend largely on the respective situation and the implementation and combination of the measures described. An in-depth analysis of respective advantages and disadvantages and the suitability of the measure is necessary in every single case. We do not assume any responsibility for and make no warranty with respect to the results that may be obtained from the use of the information provided.
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Pathogens & Contaminants
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Contents
1. Introduction
2. Characteristics of Pathogens and Contaminants
3. Pathogens
4. Contaminants
5. References
3
Pathogens & Contaminants
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The overall Problem
Substances such as pathogens (microorganisms) and contaminants (chemicals and metals) in drinking water may harm both public health and the environment. In developing countries, the contamination of drinking water with pathogens is the major factor for prevalence of diseases.
Most often, faeces infiltrating drinking water sources are responsible for contamination with pathogens. Contaminants in drinking water may originate from human activities and natural processes.
4
1. Introduction
Pathogens & Contaminants
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Types of Pathogens and Contaminants
5
2. Characteristics of Pathogens and Contaminants
Pathogens
•Bacteria• e.g. Salmonella,
Escherichia coli, Campylobacter
•Viruses• e.g. Rotavirus,
Hepatitis•Parasitic protozoa
• e.g. Giardia•Helminths (worms)
• e.g. Trichuris trichiura
Microorganisms
Contaminants
•Inorganic chemicals• e.g. nitrate,
arsenic, fluoride, chloride
•Organic chemicals• e.g. petro-
chemicals (oil, diesel), solvents, drugs, pesticides
•(Heavy) metals• e.g. cadmium,
copper, lead, mercury
Pathogens & Contaminants
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Sources of Pathogens and Contaminants
6
2. Characteristics of Pathogens and Contaminants
Source: CONSERVATION ONTARIO (2009)
•Underground storage tanks•Chemical storage•Accidental spills of
hazardous materials •Spreading of sewage
treatment sludge•Septic systems •Animal feedlots
• Storage and spreading of road salt
• Underground pipelines or sewers
• Use and spilling of fertilisers and pesticides
• Landfills• Private and abandoned
wells
Source: BUCHANAN et al. (2010)
Pathogens & Contaminants
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Dispersion of Pathogens and Contaminants
7
2. Characteristics of Pathogens and Contaminants
Source: WAL (2010)
Migration of contaminants in an unconfined (left) and a confined (right) aquifer.
Adapted from FREEZE et al. (n.y.)
Movement of insoluble contaminants in ground water:
Oil spills (lighter than water) accumulate on the water table and spread horizontally.
Pathogens & Contaminants
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General Effects of Pathogens and Contaminants
8
2. Characteristics of Pathogens and Contaminants
Drinking water contamination:
•Poor drinking water quality
•Loss of community’s drinking water supplies
•High costs for restoration and alternative drinking water supplies
•Health problems
Impacts on the environmental system by contaminants:
•Loss of ecosystem functions
Examples for related economic effects:
•Less revenue by fisheries
•Less revenue from tourism
Examples for related economic effects:
•Higher health expenses
•Restricted work force
Pathogens & Contaminants
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Transmission & Health Risks of Disease
9
3. Pathogens
Source: HESPERIAN & UNDP (2004)
Faecal-oral transmission routes:•Fingers•Flies and other insects•Fields (agriculture)•Food•Fluids
Health risks:Gastrointestinal symptoms such as diarrhoea, vomiting and stomach cramps
Pathogens & Contaminants
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Probability of Causing Infections
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3. Pathogens
Amount and variability of pathogens
Long latency periods
Persistence in the environmentLow minimal infective doses
Little or no human immunity
SHUVAL et al. (1986)
Pathogens & Contaminants
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Probability of Causing Infections
11
3. Pathogens
Sanitation system
Amount and variability of pathogens
Long latency periods
Persistence in the environmentLow minimal infective doses
Little or no human immunity
Source: http://2.bp.blogspot.com/-2yIT8xt_stM/TwtB4J9sBqI/AAAAAAAACmY/s_6-9HHksUA/s1600/Istanbul%20Toilet.gif [Accessed: 05.06.2012]
SHUVAL et al. (1986)
Pathogens & Contaminants
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Health Risks related to contaminated Groundwater
12
4. Contaminants
Possible health risks:
•Cancer
•Liver, kidney and nerve problems
•Birth defects
•Learning disabilities in children
Source: WALLIN (1997)
Source: http://www.thewaterchannel.tv/tutorial/section_4/6.html
Pathogens & Contaminants
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13
5. ReferencesBUCHANAN, B., DE LA CRUZ, N, MACPHERSON, J., WILLIAMSON, K. (2010): Water Wells that Last for Generations. Edmonton: Alberta Agriculture and Rural Development. URL: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/wwg404 [Accessed: 05.06.2012].
CONSERVATION ONTARIO (Editor) (2009): Wellhead Protection Areas. Newmarket: Conservation Ontario. URL: www.conservationontario.ca/source_protection/files/ODWSP%202009%20Finals/ODWSP_FAQS_wellhead_EN_2009_02_27_WEB.pdf [Accessed: 06.06.2012].
FREEZE, R.A., ATWATER, J., LIEBSCHER, H. (n.y.): Water Stewardship . Ground Water Resources of British Colombia. Victoria: The Province of British Columbia. URL: http://www.env.gov.bc.ca/wsd/plan_protect_sustain/groundwater/gwbc/C05_contamination.html [Accessed: 05.06.2012].
HESPERIAN FOUNDATION (Editor); UNDP (Editor) (2004): Sanitation and Cleanliness for a Healthy Environment. Berkeley: The Hesperian Foundation. URL: www.unwater.org/downloads/EHB_Sanitation_EN_lowres.pdf [Accessed: 05.06.2012].
SHUVAL H.I., ADIN, A., FATTAL, B., RAWITZ, E., YEKUTIEL, P. (1986): Wastewater Irrigation in Developing Countries. Health Effects and Technical Solutions. Washington, D.C.: The World Bank. URL: http://documents.worldbank.org/curated/en/1986/05/440564/integrated-resource-recovery-wastewater-irrigation-developing-countries-health-effects-technical-solutions [Accessed: 05.06.2012].
WAL, A. van der (2010): Understanding Groundwater & Wells in Manual Drilling. Instruction Handbook for Manual Drilling Teams on Hydro-geology for Well Drilling, Well Installation and Well Development. Papendrecht: Practica Foundation. URL: www.unicef.org/wash/files/04.pdf [Accessed: 06.06.2012].
WALLIN, R. (1997): Wellhead Protection: A Guide for Arizona Communities. TUCSON: Arizona Department of Environmental Quality, Water Quality Division. URL: http://www.unicef.org/wash/files/04.pdf [Accessed: 05.06.2012].