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Physiological value water. Hygienic requirements to drinking water. Documents, regulating quality of water. 1. Organoleptic properties drinking water.
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Physiological value water.
Daily need of the adult person in normal conditions 2, 5-3 l water, in a hot climate or at heavy physical work - till 10-12 l / day.
Water carries out structural role - the organism of the adult consists on 51-66 % of water, in organism of the child 80-90 %.
Besides water - weak electrolit, dissociate on ions Н + and OH - catalysts of biochemical reactions and water - the environment of these reactions.
HYGIENIC REQUIREMENTS TO DRINKING WATER.
Documents, regulating quality of water.
There are exist 2 State Standart (SS) quality of water:
1. The State Standart USSR 1982. (SS Ukraine 1996) " Water drinking "
2. The State Standart USSR 1974 " Water of sources of the centralized water supply ",
Last SS contains less rigid requirements to quality of water - is intended to choice source of water supply, then water pass clearing and disinfecting and after that should correspond in a waterpipe to SS " Water drinking".
WHO was developed the International standard of drinking water (ISDW-73), State Standarts USSR and Ukraine practically correspond to it.
The general requirements to quality drinking water:
1) Water should have satisfactory оrganoleptic properties.
2) Water should be harmless on chemical compound (natural and anthropogenous).
3) Water should be safe in the epidemiological relation.
These criteria are the basic group of parameters of drinking water in State Standart.
1. Organoleptic properties drinking water.
Smell and smack - up to 2 points. It is determined in the open and closed experiences in people. (Scale: 0 points – absence smell and smack, 1 - determines only odorator - the person with the increased sensitivity smells and tastes, 2 - the consumer does not pay attention, 3 - appreciable - causes the negative attitude to water, 4 distinct - limits water consumption, 5 - very strong - water is unsuitable for drink).
Colouring or chromaticity of water - up to 20 degrees. It is determined on a scale of ampoules with a chrom-cobalt solution with different color.
Turbidy - up to 1, 5 mg / l or transparency - 30 sm. It is determined with the help of special flasks – in norm must be opportunity reading the text through a layer of water in 30 sm.
Temperature - 10-120C. Below – may be cold diseases, at higher - than change оrganoleptics water.
Value studying оrganoleptic properties of water
1) It are used for Initial examination quality of water,
2) Changes organoleptic properties - indirect attribute organic pollution of water.
2. CHEMICAL PARAMETERS of WATER, IT INFLUENCE
ON THE PERSON.
The dry rest or mineralization of water - up to 1000 mg / l (1 g/l). At higher values of the dry rest (1400 mg / l and more) - changes оrganoleptic propeties of water - smack of water.
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Classification waters by a degree of mineralization:
- 1-2 g\l – water low mineralization,
- 10 g/l and more - high mineralization (seawater 35 g/l).
At the use high mineralization water (it is especial at sharp change water at moving to other district) - violations of water-salt balance, delay water in organism, violations activity of digestive and secretory systems, violations of metabolism. The increase frequency of urine and gall-stone illness is statistically shown in these districts. With such water in an organism acts 25-100 % of total amount of mineral substances of a diet.
On the other hand, experimentally and clinically it is proved, that waters with low mineralization ( 100mg/l and less) are biologically defective - secretion and acidity of gastric juice raises, is broken absorbtion waters in entestines, violations water-salt exchange, reabsorbtion in kidneys, hypocalciaemya, decrease of osmotic resistance erytrocites, etc.
Contents chlorides - up to 350 mg / l. Give to water salty smack - in the big concentration - change taste of water more than 2 points. At increasing chlorides in water it is violations of water-electrolit exchange and function of kidneys. " The Salt hypertension" - in areas with salty water arterial hypertension meets in 4 times more often. At concentration chlorides more than 500 mg / l - oppression secretion and acidity of gastric juice.
It is the indirect parameter of organic pollution water by household sewage - chlorides is a lot in urine.
Contents sulfates - up to 500 mg / l. Give to water bitter smack more than 2 points. At increase - oppression gastric secretion, break intestinal absorbtion, can be reflex dyarrea.
Also it is indirect parameter organic pollution – many sulfates in faecal masses.
General rigidity of water - up to 10 mg – equivalent / l. Depends on the contents ions Са and magnesium. It is division on eliminated (go away at boiling), not eliminated (stay in water after boiling) and general (last is normalized in SS).
Classification water by the general rigidity:
- Up to 3, 5 mg - eq/l – soft water
- 3, 5 - 7 mg - eq/l - water average rigidity
- 7 - 14 mg - eq/l – rigid water
More 14 mg - eq/l - very rigid water.
In rigid water it is bad to erase (the charge of washing-up liquids on linkage with salts), to cook products. It is worsened protein absorbtion - insoluble complexes with salts. Problems of water supply - form scum on pipes (eliminated rigidity).
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