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Nitrogen substances (Ammonia, nitrites, nitrates).
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Nitrogen substances (Ammonia, nitrites, nitrates).
Ammonia and nitrites in water practically should not be, nitrates - up to 10 mg / l (in recalculation on nitrogen). As it is final parts disintegration proteins, on them it is possible to make prescription about organic pollution: if in water is only ammonia - fresh pollution, only nitrates - old, all nitrogenous substances - proceeding pollution. It is indirect parameter organic pollution of water.
At the increased contents nitrates and nitrites (the reason: organic pollution of reservoir or going in it nitric fertilizers) it is possible special illness - water-nitrate methaemoglobynaemya (are especially dangerous to children of the first months of life).
Oxide ability of water and biochemical consumption of oxygen (BCO). The important parameter of amount of organic substances in water - for their oxidation is required more О2. In norm oxidability of water - 2-4 mg О2/l. Dynamics oxidability for 5 or 20 day - BCO - criterion of oxygen mode of a reservoir - is studied at normalization pollutants in water of reservoirs.
Contents iron - up to 0, 3 mg / l. A source of it is natural structure or water pipes. At the greater contents of it color (colouring of water) changes.
Contents fluorine - 0, 7-1, 5 mg / l (in hot climate it is possible 0, 7 mg / l - use waters more, in cool - 1, 5 mg / l). The reason of the abnormal content fluorine in water - biogeochemical provinces and anthropogenous sources (superphosphate factories). At the small content fluorine in water in people may be caries, at increased - fluorosis (spotty defeat dental enamel, infringement Са-Р exchange, fluoric cahexya, deformation and fragility bones).
3. BACTERIOLOGICAL PARAMETERS of WATER.
All over the world the following parameters microbe pollution of water are used:
а) Total number of microorganisms in water
b) The contents intestinal stick (E. Coli) as constant inhabitant of sewage and relative steadier microbe, than others, to disinfecting water - shows efficiency of disinfecting water.
Total microbe number (TNM) - up to 100 in 1 ml (amount microbe colonies at crop 1 ml of water at Petri’s cup at 37 С in 24 hours).
Coli - index - up to 3 in 1 l. Quantity intestinal sticks in 1 l waters.
Coli - titr - not less than 300. Quantity water in ml in which 1 intestinal stick is found.
Epidemiological value of water.
Water factor plays the leading part in occurrence some infectious diseases:
- Intestinal infections - belly typhus, cholera, paratyphus, dysentery e
- Anthropozoonoses - brucelosis, tularemya, the Siberian ulcer, leptospirosis
- Virus - hepatites, poliomyelitis, adenoviruses
- The pathogenic elementary - lamblya, amoebas, balantides, etc.
- Parasitic worms.
Attributes of epidemiological danger of water:
а) Direct indexes - deterioration bacteria parameters of water, presence pathogenic microbes
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в) Indirect indexes - deterioration organoleptic parameters, growth chlorides, sulfates, nitrogenous substances, oxidability water
Attributes of water epidemy
(epidemy with water-way transmission):
1) Quick mass flash the same infectious diseases
2) Territorial connection flash of diseases with the certain water source
3) After realization antyepidemic measures in the center (prohibition using water source, disinfecting water) - sharp decrease amount of diseases, are registered only separate cases (" epidemic tail" ).
4) The hot season - better conditions for duplication activators, besides the person consumes a lot of liquid - is reduced acidity of gastric juice - barrier to microbes.
THEME N 14. HYGIENE OF WATER SUPPLY.
METHODS OF THE IMPROVEMENT QUALITY OF WATER.
Hygienic characteristic sources of water supply.
There is 4 kind of sources of water supply:
1) Surface waters - open reservoirs - the rivers, lakes, water basins
2) Underground waters:
а) Subsoil waters - in ground above a water-proof layer - wells, springs
b) Interlayer waters - between water-proof layers - artesian chinks
3) Atmospheric waters (meteoric) - gathering deposits
4) Distillation seawater.
Hygienic characteristic open reservoirs.
It is the big stocks of water, are readily available. Lack - easily are exposed to pollution on natural and anthropogenous reasons. Inconstancy chemical and microbe structure - is required daily control quality water.
Ways of autopurification open reservoirs.
1) Dilution in big water masses
2) Sedimentation
3) Biochemical oxidation by microflora
4) Adsorption by hydrobionts
5) Bactericidal action UVR in the top layers - up to 50 sm
6) Neutralization
Estimation degree pollution in open reservoirs
1) Comparison parameters of water with SS or maximal permissible concentration - analytical monitoring,
2) Medical-hygienic monitoring - on parameters of health of people using water from the given reservoir
3) Ecological monitoring - on hydrobiological parameters:
а) On sensitive - display organisms (trout)
b) On organisms - filtrators - mussels - on accumulation in it pollutants
c) On qualitative and to quantity indicators hydroecosystems.
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