The Need for the HVTO Clean Water Initiative

Summary:

HVTO believes that access to clean water is the single most important component in improving the overall health of the rural poor in Cambodia. For this reason the Clean Water Initiative has been a priority since our inception in 2008. The hand-pumped water wells that HVTO installs are drilled 20-25 meters, depending on the local geology, and are capable of delivering abundant water of a far higher quality than the water pits that have been the traditional source of water. The bacteria E. coli is considered the best indicator of fecal pollution and the presence of possible pathogens in water. Based on samples taken from an HVTO well and an adjoining water pit, the very high levels of E. coli measured in the pit were completely eliminated in the hand-pumped well.
With its high annual rainfall, water is a resource that Cambodia has in abundance. Although subject to large seasonal fluctuations, the average annual rainfall in Cambodia of about two meters per year means that surface water is widely available in most areas. However, the lack of safe drinking water sources due to poor infrastructure means the country faces serious health challenges. One of these, infant mortality, illustrates the problem. According to the United Nations World Prospects Report of 2011, Cambodia has an infant mortality of 62 out of 1,000 live births. Compare this to 12 for Thailand, 8 for Malaysia and 5 for the US and UK. Most of these deaths are attributed to diarrhea caused by the consumption of unhealthy water. In addition, for those that survive infancy, diarrheal disease is also the number one cause of death for children under the age of 5 in Cambodia.
 
The Cambodian government in association with many non‐governmental organizations (NGOs) has promoted methods to filter and/or disinfect water at the point of use, but these have encountered obstacles. Where clean drinking water is unavailable the safest method in using usually heavily contaminated surface water is to boil the water prior to drinking in order to kill the biological contaminants. While this is effective if the water is thoroughly boiled and used soon thereafter, the volume available at one time is no larger than the family’s largest cooking pot. Unfortunately, if boiled water is stored to address the volume available, this water will also quickly become contaminated.
 
Groundwater, which has a high recharge rate due to the volume of rainfall, is also widely available in most areas of the country. The problem for the rural poor of Cambodia is that accessing cleaner subsurface water is difficult and/or expensive. For most access to groundwater involves the hand-digging of a well or a water pit. In the HVTO area of activity the water-table can usually be found at a depth between 3 and 5 meters. Dug below the local water table, these pits can produce water throughout the dry season. However, the water is exposed to the air and rainfall runoff from the surrounding fields and quickly becomes little more than a small pond, complete with plants, insects, frogs and small fish.
 
Analysis of HVTO Area Water
 
In September 2014 HVTO collected three water samples from the home of Hoem Hean in Rumdeng Village in Knar Pur Commune. Three separate samples were delivered to the Siem Reap Water Quality Laboratory in order to gauge the relative quality of water taken from a typical hand-dug open water well (pit), an HVTO well (Number 304) that is pumping water from a depth of 25 meters, and pumped water from the same well that has been filtered by a locally available water filter. See Water Analyses.
 
Below are photographs of the water pit, the neighboring water well provided by HVTO and the water filter which filtered the water coming from the well.
 
Typical Water Pit
 
 
 
The drilling process.
 
Well Plan
 
The completed HVTO Well # 304 and the Hoem Hean Family.
 
 
The water filter
 
 
The key difference in these three analyses, and of most important to health issues, are their biological contaminants. These are given by ‘Total Coliform’ and ‘E. Coli’ (Escherichia coli) values expressed in the number of viable cells, or colony-forming units (CFUs), per 100 milliliters. The Total Coliforms include all bacteria that are found in soil, water, and human/animal waste, and most do not cause disease. If a lab detects only Total Coliform bacteria in drinking water, the source is probably environmental and fecal contamination is considered unlikely.
 
E. coli is a subgroup of the fecal coliform and the only group of bacteria that does not reproduce in the environment. Most varieties are harmless; however some strains can cause illness. E. coli is considered the best indicator of recent fecal pollution and indicates the possible presence of disease-causing organisms.
 
In the open water well (pit) sample the Siem Reap laboratory recorded Total Coliform of greater than 600 and E. Coli of 338 CFU/100mL. These high levels are not unusual as studies taken in other parts of Cambodia have measured most Total Coliform counts from rivers, ponds, and surface pits in the thousands of CFU/mL, with many classified as TNTC (Too Numerous To Count). Those with this designation are usually greater than 8,000 CFU/mL. For this reason it is reasonable to assume that the >600 value shown for this pit sample probably contains at least several of thousand viable Coliform cells per 100mL.
 
The 338 CFU/mL of E. coli measured in the pit sample is also on a par with what has been reported in studies available online from other parts of Cambodia. In a study done in 2012 by the American Journal of Tropical Medicine and Hygiene it was found that in the 369 surface water samples studied about 45% registered E. coli counts in the 100-1,000 CFU/mL range and an additional 30% had counts that were greater than 1,000 CFU/mL. The level of E. coli in this sample indicates recent fecal contamination and the likely presence of disease-causing bacteria.
 
The number of Total Coliforms in the pumped water sample from the HVTO well # 304 was dramatically less at 190 CFU/mL. Although this does indicate that some source of environmental contamination is present, this level is a major improvement over the water sample from the pit. Of much greater importance, the level of E. coli in the same sample was reduced to nil. Although not to the standards of the developed world, this indicates no fecal contamination and a relatively low probability of health risks associated with its use. When this pumped water was further filtered using the water filter, both Total Coliform and E. coli bacteria levels were both reduced to nil. When used straight out of the filter this water is clearly the highest quality of the three samples measured.
 
Several other water parameters were measured, and with the exception of the expected high turbidity in the surface pit water, most were close to or below the guideline limits shown. None of these elements represent major health issues. The unfiltered well water, having percolated through 25 meters of iron-rich sediment, has more iron in it than the other samples. However, iron is classified as a ‘Nuisance Chemical’ giving water a metallic taste and staining fixtures.
It should be noted that in parts of Cambodia, as well as surrounding countries, significant levels of arsenic are found in groundwater samples. The presence of this poisonous element is strictly a function of the mineralogy of the sediment and rock through which the water flows underground, and thankfully arsenic is not a problem in any of the areas in which HVTO operates.
 
 
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