Presentation on theme: "2° YEAR I.G.E.A.. According to the law mineral water must come from underground natural water sources protected from contaminations and it must be pure."— Presentation transcript:
2° YEAR I.G.E.A.
According to the law mineral water must come from underground natural water sources protected from contaminations and it must be pure from bacteria. Adding carbon dioxide and eliminating iron and sulphur are allowed. In order to be considered as drinkable, tap water must be colourless and odourless, clear and fresh.
H 2 S (Sulphuric Acid) H 2 S (Sulphuric Acid) HARDNESS HARDNESS PH PH ALKALIS ALKALIS NITRATES NITRATES NITRITES NITRITES
Hardness, which is expressed in French degrees (°F), indicates the presence of calcium and magnesium in water, that is if water is more or less calcareous. Following CEE directives, water with hardness inferior to 30 °F are considered as “sweet", that is containing little limestone. Hard water springs especially from calcareous soils, while in soils with a higher percentage of granite, slate or green-sand, the quality of water tends to be sweeter. At high temperatures hard water leads to the formation of limestone (as it happens in water pipes or in the case of some particular electrical appliances); this causes higher energy consumption, since limestone is a bad heat conductor.
L'acidità è una delle proprietà più importanti dell'acqua. L'acqua è un solvente per quasi tutti gli ioni. Il pH serve da indicatore che confronta alcuni degli ioni più solubili in acqua. Il risultato di una misura di pH è determinato da un confronto tra il numero di ioni H+ ed il numero di ioni ossidrile (OH-). Quando il numero di ioni H+ è uguale al numero di ioni OH-, l'acqua è neutra, cioe' ha un pH di circa 7. Il pH dell'acqua può variare fra 0 e 14. Quando il pH di una sostanza è superiore a 7, è una sostanza basica. Quando il pH di una sostanza è inferiore a 7, è una sostanza acida.
Capacity of water to neutralize an acid or a base, so that this pH doesn’t change
Nitrates are compounds made of nitrogen (N) and oxygen (O). Man takes in nitrates mainly through drinking water and vegatables. Nitrates are harmless. Under some circumstances (for ex. in case of long conservation, heat, acidic pH ) they can turn into nitrites, which have harmful effects. The in-take of nitrates should therefore be limited as much as possible.
Nitrites are compounds made of nitrogen (N) and oxygen (O). Under particular circumstances nitrates turn into nitrites. This reaction can take place in the soil, in drinking water, in food and the human body. Nitrites are toxic substances; binding to haemoglobin (blood protein carrying oxygen to body tissues) they hinder oxygenation. At greater risk are newly-born babies who can have breathing problems and in extreme cases asphyxiation due to poor oxygenation.
Sulfate is one of the main elements dissolved in the rain. High sulfate concentraions in drinking water can have a laxative effect if they are joined with calcium and magnesium, the two most common elements of hardness. The bacteria which attack and reduce sulfates make up hydrogen sulphide gas (H2S).
Why should we drink tab water again ? The answer is simple and articulated at the same time. Let’s clear any doubt: taP water is controlled and safe. Of course, in case of an excessive use of chlorine it might be organoleptically unpleasant; in this case just follow this simple tip: since chlorine is volatile, you simply need to let tap water rest in a jug for about 10 minutes so that chlorine can evaporate; try! Drinking water is safe because it must comply with lots of hygenic measures. The guarantee of its drinkability is sure: if tap water flows out of our home pipes, it’ s safe because it is tested as drinkable! Should just one criterium not be respected, the Mayor of the Town is compelled to pass a bill of not drinkability: a guarantee for our health.
DRINKING WATER MINERAL WATER HARDNESS °F ( French degrees ) Foreseen parameter but without limitations PH6,5 - 8 Foreseen parameter but without limitations NITRATES50 mg/l mg/l NITRITES0,1 - 0,5 mg/l0,02 mg/l H2SH2S250 mg/l Foreseen parameter but without limitations