We explain what drinking water is and what are the main characteristics. In addition, its chemical and microbiological characteristics.
Which is the potable water?
Water is an increasingly scarce resource and many populations in the world still remain without access to a source of drinking water. Institutions such as UNICEF and the World Health Organization (WHO) have the issue of access to drinking water as one of their priority objectives , since there is a direct relationship between access to drinking water and health.
The WHO specifies that there is access to drinking water when its source is less than 1 kilometer away from the place of use, and whenever it is possible to reliably obtain at least 20 liters per day for each member of the family.
Drinking water characteristics :
Clean and safe
Using clean water and preparing food with clean water greatly reduces the likelihood of acquiring infectious diseases (including serious diseases, such as cholera, typhus, or leptospirosis) and non-infectious diseases (such as methemoglobinemia).
In rural areas, drinking water is obtained from underground wells or springs.
To make potable water from the mains from surface intakes that are not naturally drinkable (such as the Río de la Plata), a fairly complex corrective treatment must be carried out, which involves a first rough filtering in the intake or intake stage, and then elevation , coagulation, decantation, filtration and finally chlorination and alkalization.
In rural areas , where there is no potable water distribution system, the water often comes from deep underground sources (wells) or springs . The degree of contamination of these waters in general is not so high, which makes it possible to resort to the oldest and most universal method of disinfection of water at the household level: boiling the water. In this way at least the elimination of most of the pathogens ( bacteria and viruses ) that are transmitted through water is achieved , although it does not solve the problem of contamination with heavy metals , for example.
Filtration is also a simple method that removes intestinal parasite cloudiness and cysts, but fails to suppress smaller living things, such as viruses and bacteria.
Drinking water should not be colored , although it may be somewhat whitish due to chlorination.
Drinking water should not have an odor , as it should not contain anything that could generate it.
Neither must have taste.
Free of suspended elements
Drinking water should not have floating particles that create turbidity.
It should not contain floating particles that generate turbidity.
- pH between 6.5 and 8.5
- Minimum residual active chlorine: 0.2 mg / l
- Fluorides (F - ): 0.9 (lower limit); 1, 7 (upper limits) in areas with an average temperature of 10 ° C (in warmer areas, the limits are lower)
- Total hardness (as calcium carbonate): no more than 400 mg / liter
- Maximum chemical contents (in mg / liter):
- Total iron (Fe): 0.30
- Manganese (Mn): 0.10
- Mercury (Hg): 0.001
- Nickel (Ni): 0.02
- Nitrate (NO 3 - ): 45
- Nitrite (NO 2 - ): 0.10
- Silver (Ag): 0.05
- Lead (Pb): 0.05
- Selenium (Se): 0.01
- Sulfates (SO 4 = ): 400
- Ammonia (NH 4 + ) 0.20
- Aluminum (Al): 0.20
- Arsenic (As): 0.01
- Boron (B): 0.5
- Bromate: 0.01
- Cadmium (Cd): 0.005
- Cyanide (CN - ): 0.10
- Zinc (Zn): 5.0
- Chloride (Cl - ): 350
- Copper (Cu): 1.00
- Chromium (Cr): 0.05
You may be interested in: Chemical characteristics of water .
No organic pollutants
Nor should drinking water contain residues of organic substances such as pesticides, that is why there are maximum limits for compounds such as benzene or DDT .
Drinking water must have an absence of Escherichia coli in 100ml.
Limits are set to minimize the risk of contracting infectious diseases , basically childhood diarrhea, which are a major cause of malnutrition and mortality in underdeveloped areas. These limits are:
- Less than 100 colony forming units (CFU) per ml of total aerobic bacteria
- Less than 2 the most probable number (MPN) of coliform bacteria per 100 ml
- Escherichia coli : absence in 100 ml
- Pseudomonas aeruginosa : absence in 100 ml
Defined by regulatory institutions
The National Food Code of the Argentine Republic, in its article 982, defines drinking water for public supply and drinking water for home use as that suitable for food and domestic use ; and specifies that it must not contain foreign substances or bodies of biological, organic, inorganic or radioactive origin in concentrations that make it dangerous to health. In addition, it must be clear and transparent.
The above content published at Collaborative Research Group is for informational and educational purposes only and has been developed by referring reliable sources and recommendations from technology experts. We do not have any contact with official entities nor do we intend to replace the information that they emit.