Pro-oxidant activity of vitamin C in drinking water ... - Ãbo Akademi

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Review of the literatureFormation of free radicals during physiological conditions, for example OH • radicals, willset off a chain reaction between newly formed radicals and non-radicals. This chainreaction will not stop until two free radicals meet and react with each other.3. Drinking waterWater is necessary for all life and human cells consist of 80 percent water. Therefore,humans must drink water frequently to maintain their fluid requirement. Humans need todrink approximately 2 litres (8 glasses) of water every day to replenish the water that is lostfrom the body through urine, skin and the respiratory tract. However, only 0.3% of theEarth’s water supply is safe to drink. Only freshwater originating from rivers, lakes andunderground sources can be used for human consumption. In addition, freshwater frommany of these sources is unsuitable for human consumption, because of contaminants. Thecontaminants must be removed or adjusted to accepted threshold values.3.1. Drinking water impurities and Maximum Contaminant Level (MCL)Drinking water contains impurities from both natural and man-made sources. Gases,minerals, bacteria, metals and chemicals are examples of contaminants that have to beadjusted to accepted threshold values. This restriction of contaminants in drinking water isnecessary to protect public health and ensure a uniform standard for water qualitynationwide. Private water wells, on the other hand, are not regulated by drinking waterstandards. The owner of the well is responsible for testing, and if needed, treating the waterhimself, all to avoid health risks. The Maximum Contaminant Level (MCL) is the highestamount of a specific contaminant that is allowed in the drinking water. The MCL isnormally expressed in milligrams per litre (mg/l). 154, 155Contaminants fall into two categories, primary and secondary contaminants. The primarystandards serve as threshold value for the contaminant to avoid health problems.Radioactive elements, microbial pathogens and organic/inorganic chemicals are examplesof three classes of toxic pollutants that are classified as primary contaminants. Water plantsare obliged to follow MCL for primary contaminants.Secondary contaminants are regarded as contaminants that affect the aesthetic quality ofdrinking water, such as taste, colour, odour, pH and appearance. Chloride, sulphate,copper, iron, manganese, zinc etc. are all examples of secondary contaminants (Table 3).21
Review of the literatureWater plants are not forced to fulfil the MCL values for secondary contaminants but serveas guidelines for good-quality drinking water. Thus, if the contaminants in drinking waterare lower than the MCL, it is believed that a person can consume the drinking water safelyover a lifetime.Table 3. Guideline values (MCL) for some cations and anions that are ofhealth significance in drinking waterGuideline value (MCL) (mg/l)WHO standards EU standardsChemical 1993 1998CationsAluminium 0.2 0.2Arsenic 0.01 0.01Cadmium 0.003 0.005Calcium not mentioned 100Chromium 0.05 0.05Copper 2.0 2.0Iron not mentioned (1) 0.2Lead 0.01 0.01Nickel 0.0 0.02Magnesium not mentioned 50Manganese 0.5 0.05Zinc 3.0 not mentionedAnionsChloride 250 250Cyanide 0.07 0.05Fluoride 1.5 1.5Sulphate 500 250Nitrate 50 50Nitrite 0.5 0.1The WHO guideline values for cations and anions were adapted from“Guidelines for drinking water quality”, Geneva 1993. 154 European guidelinevalues were adapted from the Council Directive 98/83/EC on the quality ofwater intended for human consumption. 155 Remarks: (1) Desirable 0.3 mg/l22
Page 1 and 2: Pro-oxidant activity of vitamin C i
Page 3 and 4: Supervised byDocent Tommy Nordströ
Page 5 and 6: ContentsCONTENTSLIST OF ORIGINAL PU
Page 8 and 9: List of original publicationsLIST O
Page 10 and 11: AcknowledgementsACKNOWLEDGEMENTSThi
Page 12 and 13: AbbreviationsABBREVIATIONSAsc …
Page 14 and 15: Review of the literatureREVIEW OF T
Page 16 and 17: Review of the literatureSince vitam
Page 18 and 19: Review of the literaturestill added
Page 20 and 21: Review of the literatureantioxidant
Page 22 and 23: Review of the literatureThe α-toco
Page 24 and 25: Review of the literatureCopper, wil
Page 26 and 27: Review of the literatureOH • + H
Page 30 and 31: Review of the literature3.2. The ro
Page 32 and 33: Review of the literaturecopper conc
Page 34 and 35: Experimental proceduresEXPERIMENTAL
Page 36 and 37: Experimental procedures2.2. Measure
Page 38 and 39: Experimental procedurestetrahydrate
Page 40 and 41: ResultsRESULTS1. Vitamin C induces
Page 42 and 43: Results3. Oxidative decomposition o
Page 44 and 45: Resultsdifferent water samples vari
Page 46 and 47: DiscussionDISCUSSIONNowadays, ascor
Page 48 and 49: DiscussionCu 2+ + Asc → Cu + + As
Page 50 and 51: Discussion3. Iron inhibits vitamin
Page 52 and 53: Discussionperoxide might have an im
Page 54 and 55: ConclusionsCONCLUSIONSThe main focu
Page 56 and 57: ReferencesREFERENCES1. Arrigoni O,
Page 58 and 59: References34. Padayatty SJ, Katz A,
Page 60 and 61: References66. Sies H, Stahl W, Sund
Page 62 and 63: References95. Halliwell B. Role of
Page 64 and 65: References127. Park S, Han SS, Park
Page 66 and 67: References157. Critchley MM, Cromar
Page 68 and 69: References185. Liao CH, Kang SF, Wu
Page 70 and 71: References214. Orr CW. Studies on a
Page 72: References243. Miller C, Kennington
Page 88 and 89:
Free Radical Research, Volume 38 Nu
Page 90 and 91:
VITAMIN C OXIDATION IN DRINKING WAT
Page 92 and 93:
VITAMIN C OXIDATION IN DRINKING WAT
Page 94 and 95:
Free Radical Research, May 2005; 39
Page 96 and 97:
Iron inhibits Vitamin C/copper-indu
Page 98 and 99:
Iron inhibits Vitamin C/copper-indu
Page 100 and 101:
Free Radical Research, November 200
Page 102 and 103:
Hydrogen peroxide formation in drin
Page 104 and 105:
Page 106 and 107:
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