How many may be are at risk?
2,1 billion people lack access to an “improved” drinking water supply. Many more drink water that is grossly contaminated.
How many are getting sick?
4 billion cases of diarrhoea occur annually, of which 88% is attributable to unsafe water and inadequate sanitation and hygiene.
How many are dying?
1.8 million people die every year from diarrhoeal diseases, the vast majority are children under 5.
How many more cannot escape poverty?
Lack of safe water perpetuates a cycle whereby poor populations become further disadvantaged, and poverty becomes entrenched.
How much of this can be prevented?
It is estimated that 94% of diarrhoeal cases are preventable through modifications to the environment, including interventions to increase the availability of clean water and to improve sanitation and hygiene.
The amount of fresh water is limited and it continuously repeats its journey of: evaporation from the ocean (leaving the salt behind); formation of clouds; precipitation of rain; groundwater and surface water; and back to the salty ocean.
Water (H2O), is one of the most abundant liquids on our planet. The fresh water we use for drinking, washing and preparation of food comes from:
Water of good quality is that which is free from disease-causing organisms called pathogens. Good quality water is necessary to reduce the incidence of common diarrheal diseases.
Microbial water quality is the state of the water with respect to the absence (good water quality) or presence (poor water quality) of microorganisms. Microbial water quality is usually indicated by reporting the number of indicator organisms present in a given volume of water.
Water resources can directly be contaminated by natural runoff from rainfall events, or can be polluted by runoff from such activities as intensive animal feedlots or by untreated sewage wastes.
In the management of waterborne diseases, it is important not only to look at the large events, but also at activities in the home and in the workplace. For example when a jug or bucket of water is filled from a tap in the home, if the tap is connected to a well-treated water supply, the water may be microbially safe as it leaves the tap but it may subsequently be contaminated in the jug/ bucket, due to:
So, water can be readily contaminated in the home at the point of use.
There are of course other routes of water pollution, for example, the water that is used to flush the toilet becomes highly contaminated with faecal matter, and must be treated at the wastewater treatment works before it is safe to discharge into rivers or dams in the environment.
Water may also be contaminated in the kitchen through washing food and dishes and cutlery either before or after the preparation of a meal.
Domestic water is considered to be safe when the count for “zero indicator organisms” has been met. The indicator faecal organisms used for this purpose are, usually, either the faecal coliform count or the Escherichia coli (E. coli) count.
It is not practically feasible to have the indicator organism count to be zero at all times, and a management rule, which is usually adopted is to ensure that the indicator goal count of zero is achieved for at least 95% of the samples tested during any given year.
If disease-causing microorganisms are present in large enough numbers, this may overwhelm the immune system and so bring disease and suffering.
The environment is teeming with microorganisms, such as bacteria, protozoa and viruses. Yet most of these do not cause disease in healthy individuals, due to the action of the immune system, which recognizes the penetration of the foreign proteins into the bloodstream and destroys them before they can multiply and damage body tissues and functioning and so cause disease. The immune system has, however, its limitations.
The immune system is more easily overwhelmed and compromised in infants and young children, where the immune system is still developing, and in the elderly when the system begins to fail. As a result children and the elderly tend to be more susceptible to certain water borne diseases, in particular gastroenteritis.
There are situations where the immune system has been weakened by other events. For example, the immune system is also compromised in certain disease conditions, such as AIDS, and as a result of immune suppression, e.g. treatment of cancer or recipients of organ transplants. In such immuno-compromised individuals it is essential that they be provided with drinking water of high quality and free of the disease-causing pathogens.
There are an enormous variety of microorganisms that can be found in the environment, ranging from tiny viruses (such as those that causes Hepatitis) that can only be seen under an electron microscope to the singled-celled bacteria (such as the bacterium causing cholera). It is quite right that without water there is no life, and in many ways, this is true for microorganisms as well. They require moisture and nutrients to multiply (e.g. in the case of bacteria).
No, not all microorganisms are harmful to your health. The human intestine is teeming with bacteria, known as the normal gut flora. These help to digest food residues and also are responsible for the production of vitamin B12 in the gut. These gut floras constitute a large portion of the bulk of the faeces, together with the undigested cellulose from the food. The result is that faecal material is teeming with bacteria, being over a million bacterial cells in a gram of faecal material.
Friendly microorganisms also play a key role in priming (stimulating) the immune system to develop antibodies against the more dangerous and disease causing bacteria.
The most common routes for microorganisms to enter the human body are through:
Continue reading: Waterborne Diseases Factsheet