65/2004. (IV. 27.) Regulation
Determination of mineral water consistuents
The Natural Mineral Water and Bottled Drinking Waters
Judit Szuetta 2007.
[email protected]
„natural mineral water” means:
Is microbiologically wholesome Originates in an underground water table or deposit and emerges from a spring tapped or more natural or bore exits free of any contamination
Allowable operations modify the physico-chemical composition of the water in terms of its characteristic constituents separating compounds of iron, manganese, sulphur and arsenic with air total or partial elimination of free carbondioxide by exclusively physical methods
Treatment of natural mineral waters and spring waters with ozone-enriched air shall only be carried
Treatment of natural mineral waters and spring waters with ozone-enriched air shall not
out if is for the purpose of separating compounds of iron, manganese, sulphur and arsenic from water in which they occur naturally at source do not modify the physico-chemical composition of the water in terms of its characteristic constituents
have a disinfectant action bacteriostatic agent (the viable total colony count of water)
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After bottling, the total colony count at source may not exceed– (a) 100 per ml at 20 to 22°C in 72 hours on agar-agar or an agar-gelatine mixture; and (b) 20 per ml at 37°C in 24 hours on agar-agar. The total colony count shall be measured within the period of 12 hours following bottling, the water being maintained at 4°C during that period
At source: the water colony count is that determined per ml of water– (a) at 20 to 22°C in 72 hours on agar-agar or an agar-gelatine mixture; (b) at 37°C in 24 hours on agar-agar.
Water shall be free from
parasites and pathogenic microorganisms Escherichia coli and other coliforms and faecal streptococci in any 250 ml sample examined Clostridium perfringens Pseudomonas aeruginosa
Markings of the carbon dioxide added waters
„naturally carbonated natural mineral water” „natural mineral water enriched with gas from the spring” “carbonated natural mineral water” „fully decarbonated” „partially decarbonated”
Equipment for exploiting the water must be so installed as to avoid any possibility of contamination and to preserve the properties corresponding to those ascribed to it which the water possesses at source The spring or outlet must be protected against the risks of pollution The catchment, pipes and reservoirs must be of materials suitable for water and so built as to prevent any chemical, physico-chemical or microbiological alteration of the water the conditions of exploitation, particularly the washing and bottling plant, must meet hygiene requirements.
Forbidden any designation, proprietary name, trade mark, brand name, illustration or other sign, whether emblematic or not, the use of which suggests a characteristic which the water does not possess, in particular as regards its origin, the results of analyses or any similar references to guarantees of authenticity any indication, attributing to the natural mineral water properties relating to the prevention, treatment or cure of a human disease indication, attributing to the natural mineral water properties relating to the prevention, treatment or cure of a human illness
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Maximum limits for constituents of natural mineral waters constituents
limits (mg/l):
Antimony
0,0050
Arsenic
0,010
Barium
1,0
Boron
3,0
Cadmium
0,003
Chromium
0,050
Copper
1,0
Cyanide
0,070
Fluoride
5,0
Lead
0,010
Manganese
0,50
Mercury
0,0010
Nickel
0,020
Nitrate
50
Nitrite
0,1
Selenium
0,010
Should be determined the temperature of the water at source and the ambient temperature the dry residues at 180°C and 260°C the electrical conductivity the hydrogen ion concentration (pH); the anions and cations; the non-ionized elements the trace elements the radio-actinological properties at source
treatment residue
clinical and pharmacological analyses
treatment residue clinical and pharmacological analyses must be carried out in accordance with scientifically recognised methods and should be suited to the particular characteristics of the natural mineral water and its effects on the human organism, such as diuresis, gastric and intestinal functions, compensation for mineral deficiencies.
Indications for mineral water indications Low mineral content Very low mineral content Reach in mineral salts Contains hydrogen-carbonate Contains sulphate Contains chloride Contains calcium Contains magnesium Contains fluoride Contains iron Acidic Contains sodium Suitable for a low-sodium diet
Criteria Mineral salt content , less than 500 mg/l Mineral salt content less, than 50 mg/l Mineral salt content, more than 1500 mg/l HCO3- content, more than 600 mg/l SO42- content more than 200 mg/l Cl- content, more than 200 mg/l Ca2+ content, more than 150 mg/l Mg2+content, more than 50 mg/l F- conte nt, more than 1 mg/l Fe2+content, more than 1 mg/l Free CO2 content, more than 250 mg/l Na+ content, more than 200 mg/l Na+ content, less, than 20 mg/l
Disolved ozone Bromates bromoforms
limits (mg/l) 50 3 1
I. Phisycal and aggregate properities
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Temperaure Temperature readings are used in the calculation of various form of alkalinty in studies of saturation and stability with respect to calcium carbonate (CaCO3), in the calculation salinity and in general laboratory operations.
Colour
Temperature Normally, temperature measurements may be made with any good mercury-filled Celsius thermometers. As a minimum, the thermometer should have a scale marked for every 0.1 OC, with marking etched on capillary glass. The thermometer should have a minimal thermal capacity permitting rapid equilibration. Periodically check the thermometer aganist a precision thermometer certified by the national Institute of Standards an Technology, thais is used with its certificate and correction chart.
Turbidity
Colour in water result from the presence of natural metallic ions, iron (iron), humic and peat materials , plankton, weeds, and industrial wastes. In some highly coloured industrial waters colour is contributed principally by colloidal or suspended material. The most important method is the Visual Comparison Method (with special calibrated colour disks)
Turbidity Turbidity in water is caused by suspended matter, such as clay silt, finely divided organic and inorganic matter, soluble coloured organic compounds, plankton and other microscopic organisms. The turbidity is an expression of the optical properity that causes light to be scattered and absorbed rather than transmitted in straight lines through the sample.
Nephelometric Method This method is based on comprasion of the intensity of light scaterred by the sample under defined condition with the intensity of light scaterred by a standard reference suspension under the same conditions. The higher the intensity of scattered light, the higher the turbidity. Formazin polimer is used as the reference turbidity standard suspension. It is easy to prepare and is more reproducible in its lightscattering properties than clay or turbid natural water.
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Mineral salts Highly mineralized water with significant concentracion of calcium, magnesium, chlorid, and/or sulfate may be hygroscopic and require prolonged drying., proper dessiciatin, and rapid weighing. Calculation: mg total solid/ L= (A-B) 1000/sample volume, (in ml) A: weigh of dired residue + dish (mg) B: weigh of dis (mg)
Total dissolved solids dried at 180 OC
A well mixed sample is filtered through a standard glass fiber filter, and the filtrate is evaporated to dryness in a weighed dish and dired to constant weight at 180 OC. The incrase in dish weigh represents the total dissolved solids.
Solids Total solids dried at 105 OC: A well-mixed sample is evaporated in weighed dish and dried to contanst weight in an oven at 105 OC. The increase in weight over that of the empty dish represents the total solids.
Aggregate organic constitument
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The chemical oxygen demand Methods for total organic carbon and chemical oxygen demand are used to assess the total amount of organic presents. Gross fractions of organic matter can be identified analitically, as in the measurement of BOD, wich is an index of the biodegradable organics present, oil, and grease, which represents material extractable from a sample by a nonpolar solvent, or total organic halide (TOX), which measures organically bound halogens.
The chemical oxygen demand is used a a measure of oxygen equivalent to the organic matter content of a sample that is susceptible to oxidation by a strong chemical oxidant. The test is useful for monitoring and control .
CODps KMnO4 , is the oxidant 2KMnO4=K2O+5O Add to the sample oxalic acid and it is react to the residual potassium-permanganate 2KMnO4+3H2SO4+5H2C2O4=K2SO4+2MnSO4+8H2O+10 CO2
Total Organic Carbon (TOC) The organic carbon in water is composed of variety of organic compounds in varios oxidation states. Some of these carbon compounds can be oxidized further by biological or chemical processes, and the biochemical oxygen demand (BOD) and chemical oxygen demand (COD) may be used to characterize these fractions.
TOC To determine the quantity of organically bound carbon, the organic molecules must be broken down to single carbon units and converted to a single molecular form that can be measured quantitatively. TOC methods utilize heat, and oxygen, ultraviolet irradiation, chemical oxidants or combinations of these oxidants to convert organic carbon to carbon dioxide (CO2). The CO2 may be reduced to methane (CH4) and measured with flame ionization decetor, or CO2 may be titrated chemically.
Inonganic nonmetallic constituents
They can be determined by classical wet chemical techniques and their automated variations and such modern instrumental techniques as ion chromatography
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Determination of anions by ion chromatography Determination of common anions such as bromide, chloride, fluoride, nitrate, phosphate, and sulfate. Although conventional colorimetric, electrometric, or titrimetric methods are available for determining individual anions, only ion chromatography provides a single instrumental technique that may be used for their rapid, sequential measurement.
A water sample is injected into a stream of eluent and passed through a series of ion exchangers. The anions of interest are separeted on the basis of the their relative affinities for a low capacity, strongly basic anion exchanger (separator columns). The separeted anions and their acid forms are measured by conuctivity. They are identified ont he basis of retention time as compared to standards.
NH4+, NO2-, NO3analysis with spectrometric methods Quantitation is by measurement of peak area or peak height. A water sample is injected into a stream of eluent and passed through a series of ion exchangers. The anions of interest are separeted on the basis of the their relative affinites for a low capacity, strongly basic anion exchanger (separator columns). The separeted anions and their acid forms are measured by conductivity. They are identified on the basis of retention time as compared to standards. Quantitation is by measurement of peak area or peak height.
They indicate contamination of human origin. They are determined by spectrometric methods.
Preparation of standards Prepare standard solutions of known ion concentrations in water with a matrix similar sample. We add different reagent solutions to the sample. They became different colours, depending on the concentrations.
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Chloride (Cl-) Chloride is one of the major inorganic anions in water and wastewater. Argentometric method In a neatrual or slightly alkaline solution, potassium chromate can indicate the end point of the silver nitrate titration of chloride. Silver chloride is precipitated quantitavelity before red silver chromate is formed. NaCl+AgNO3 =NaNO3+AgCl K2Cr2O4+2AgNO3= A KNO3+Ag2CrO4
Sulfate SO4 Sulfate is widely distributed in nature and may be present in natural waters in concnetration ranging from a few several thousand milligrams per liter. Na2SO4+BaCl2=2 NaCl+BaSO4
Alkalinity
Na2SO4+BaCl2=2 NaCl+BaSO4 Gravimetric method We use this method for accurate results. Sulfate is precipitated in hydrochloric acid (HCl) solution as barium sulfate (BaSO4), by the addition of barium chloride (BaCl2). The precipitation is carried out near the boiling temperature and after the period of digestion the precipitate is filtered, washed with water until free of Cl-, dried and weighed as BaSO4. We use membran filter with pore size of about 0.45 µm
Hardness: Hard is water that has a high mineral content. This water consist of high level calcium ( Ca2+) and magnesium (Mg2+) in the form of carbonates, bicarbonates and sulfates. Total water hardness including both Ca2+ andMg2+ ions reported CaO ppm
Permanent hardness Permanent hardness is hardness that cannot be removed by boiling. It is usually caused by the presence of calcium and magnesium sulfates and clorides in water. This can be removed by ion exchange column.
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Ca(HCO3)2 Mg(HCO3)2 NaHCO3 KHCO3 This compounds cause the water alkalinity
Temporary hardness
Temporary hardness is hardness that can be removed by boiling. It is casued by combination of calcium ions and bicarbonate ions in the water. Boiling, which promotes the formation of carbonate from bicarbonate, will precipitate calcium carbonate out of solution, leaving water that is less hard on cooling. This is the reaction when the calcium carbonate is dissolved in water: CaCO3 (s) + H2O (l) + CO2 ↔Ca2+ (aq) + HCO3-
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Temporary hardness EDTA titrimetric method Ethylene-diamine-tertaacetic acid its sodium salts. (abbrevited EDTA) form a chelated soluble copmlex when added to a solution of certain metal ions. If a small amount of a dye such as Eriochrome Black T is added to a water that is containing calcium and magnesium ions at pH of 10 the solutions becomes wine red. If EDTA is added as a titrant, the Ca and Mg ion will be complexed.
pH ( H+ concentrtation) measurment of pH is one of the most important test in water chemistry. Practically every phase of water supply and wastewater treatment e.g., acid-base neutralization, water softening, coagulation and corrosion control is pH-dependant. pH used in alkalinity and carbon dioxide measurment and many other acidbase equilibria. At given temperature the intensity of the acidic or basic character of a solution is indicated by pH or hidrogen ion activity.
Electrometric method The basic principle of electrometric pH measurment is detremination of activity of the hydogen ions by potenciometric measurment using standard hydrogen electrode and a reference electrode. We use glass electrode. The electromotive force produced in the galss electrode system varies lineary with pH. The pH measuring instrument is calibrated with buffers.
Ca2+
EDTA Murexid indicator
Pure water is very slightly ionized and at equilibrium the ion production is [H+][OH-]=Kw=10-14 And [H+]=[OH-]=10-7 Where [H+]: activity the hidrogen ions , moles/L [OH ]: activity the hidroxyl ions , moles/L Kw: ion product of water pKW= pH+pOH=14 where: pH: -log10 [H+] (negative commom logarythm of hydrogen ion concentration) pOH: -log10 [OH-] At 25 OC, pH 7.0 is neatrual, the activities of the hydrogen and hydroxil ions are equal, and each corresponds to an approximate activity 10 -7 mol/l. The neutral point is temperature-depending and it is 7.5 at 0 OC, 6.5 at 60 OC.
We can use for standards:
The potassium hydrogen tartarate: KHC4H4O6 Potassium dihydrogen citrate : KH2C6H5O7 Disodium hydrogen phosphate: KH2PO4
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Conductivity Conductivity , is a measure of ability of an aqueous solution to carry an electric current.
This ability depends on the presence of ions, on their total concentration, mobility on the teperature of measurement. Solutions of most inorganic copounds are relatively good conductors. The molecules of organic compounds that do not dissociate in aqueous solution conduct a current very poorly.
Conductance, G, is defined as the reciprocal of resistance., R G=1/R In the laboratory, conductance, (G) standard is the potassium chloride KCl solution.
Metals
Sample containers and preservation
Metals Some metals in water are essential, other may be toxic. Metals may be determined statisfactorily by atomic absorption, inductively coupled plasma, or with colorimetric method. The absorption method include flame and electrothermal techniques. Flame methods generally are applicable at moderate concentration levels in clean and complex-matrix system. Electrothermal methodes generally can increase sensivity if matrix effects are not severe. Matrix modifiers may compensate for some matrix effects. Inductively coupled plasma (ICP) techniques are applicable within a broad linear range and are especially sensitive for refractory elements.
Metals by flame atomic absorption spectrometry (AAS)
The best sample contaniers are made from quartz or teflon. Because these containers are expensive, the preferred sample container is made from polypropylene or polyethylene. Preserve samples immediately after sampling by acidifying with concentrated nitric acid (HNO3), to pH
