Appendix: parameters listed in this report
Total alkalinity and Bicarbonate alkalinity
The term ‘alkalinity’ refers to the quantity of salts with alkaline properties dissolved in the water. It indicates the capacity of the water to react with hydrogen ions and represents its capacity to "resist" induced changes to its pH. Generally, the higher the alkalinity, the lower the aggressiveness of the water.
Alkalinity that stems from carbonates and bicarbonates is not harmful to human health. Consequently, Italian laws on drinking waters do not establish an admissible maximum guideline value for this parameter.
[No regulatory limit is set for mains water network. As for mineral water, the parameter is specified but no limit is set.]
Alkylphenols/Polyalkylphenols
Alkylphenols are organic chemicals characterised by a phenolic group to which an alkyl group is bonded. There are several alkyl groups in polyalkylphenols. They include nonylphenols, octylphenols, and their respective ethoxylates - in particular nonylphenol ethoxylate (NPs) - are commonly used alkyl phenolic compounds. The textile industry widely uses nonylphenols for washing and dyeing processes. They are toxic to aquatic life, persistent in the environment because they do not degrade easily, and can accumulate in living organisms until they reach humans through contamination of the food chain. Their similarity to natural estrogen hormones may interfere with the sexual development of certain organisms. In fish they cause feminization. Europe has strict regulations on nonylphenols, which since 2005, cannot be used in most applications.
Alluminio
One of the most widely used metals and one of the most common compounds in the Earth's crust.
[Regulatory limit for mains water network: 200 µg/L (indicator parameter). As for mineral water, the parameter is specified but no limit is set.]
Ammonium
A substance that mostly derives from human or animal faeces where it is contained together with the urea that stems from protein metabolism. It may also be contained in agricultural fertilizers. In some cases, its presence in the water - especially underground water - can relate to geological factors such as decomposition of material during the fossilization process (plant remains, peat deposits, etc.). It biodegrades into the environment and is correlated with nitrates and nitrites. Its presence in water is admissible up to a maximum value of 0.50 mg/l.
[Regulatory limit for mains water network: 0.50 mg/l (indicator parameter). As for mineral water, the parameter is specified but no limit is set.]
Pesticides-Total
Pesticides are chemical products typically used in agriculture to control, turn away, or kill animal organisms such as insects and microbes. The value indicates the sum of individual pesticides measured and quantified during the analysis procedure.
[Regulatory limit for mains water network: 0.50 µg/L (chemical parameter). As for mineral water, the parameter must not "be detectable with methods that have the lower analytical efficiency limits" defined by law.]
Arsenic
Arsenic is a chemical element found in the Earth's crust. Its compounds are used as pesticides, herbicides, and insecticides. It can seriously affect human health, is included on the list of toxic elements, and has a maximum threshold of 10 μg/l. Arsenic may be present in water following its interaction with volcanic rock.
[Regulatory limit for mains water network: 10 µg/L (chemical parameter). As for mineral water, the parameter must not exceed 10 µg/L calculated as total Arsenic.]
Cadmium
Cadmium is chemically similar to zinc. It is a naturally occurring substance in sulphur rocks, often associated with lead. In the environment, high concentrations of metal in air, water and ground are due to human-made emissions, in particular mining and metalworking. It may also be present in zinc piping and welds. In natural waters, cadmium is mainly present in deep sediments and suspended particles. In unpolluted natural water it is usually present in low concentrations (<1 µg/L).
[Regulatory limit for mains water network: 5 µg/L (chemical parameter). As for mineral water, the limit is 3 µg/L.]
Calcium
Calcium is a soft alkaline earth metal, the fifth most abundant element in the Earth's crust and essential to all life. Calcium plays a major role in a balanced diet. A lack of calcium slows bone formation and tooth growth and weakens them: vice versa, a diet too rich in calcium can lead to kidney stones in persons with renal illnesses. A human body typically contains about a kilogram of calcium, of which 99% is in the bones and the rest in the blood. When water runs through calcareous rocks or other carbonate rocks, it dissolves a small part and creates caves with characteristic rock formations such as stalactites and stalagmites. When water leaves these caves, it is saturated with carbonates and is called "hard".
[No regulatory limit is set for mains water network. As for mineral water, the parameter is specified but no limit is set.]
Chlorite
Chlorites are disinfection by-products. There are no major concerns about the health effects of these compounds. However, the World Health Organisation (WHO) identifies 700 μg/l as a provisional guideline value. That limit has been transposed into Italian law as the admissible maximum.
[Regulatory limit for mains water network defined by Italian Legislative Decree of 5 September 2006: 700 µg/L (chemical parameter). As for mineral water, the parameter is not specified.]
Residual chlorine
This parameter indicates that the water has undergone a disinfection process that ensures it is microbiologically safe as it is carried through the mains distribution network. The standard does not set a compulsory value but does recommend - where used - that a concentration of 0.2 mg/l be observed.
[Parameter with a recommended concentration of 0.2 mg/l. As for mineral water, the parameter is not specified.]
Chloride
Chloride ions in water may have a mineral or organic origin. In the latter case, any unusual increases in concentration may be linked to organic pollution. Chloride increases the electrical conductivity of wate, therefore dry residue. Excessive chloride concentrations in water can accelerate the corrosion of metals used in piping, especially if associated with an acid pH.
[Regulatory limit for mains water network: 250 mg/l (indicator parameter). As for mineral water, the parameter is specified but no limit is set.]
Hydrogen ion concentration (pH)
It indicates the degree of acidity of the water. Values that are too high or too low compared to neutrality (pH = 7) may indirectly signify danger: overly acidic water (pH <7) can corrode metal pipes and dissolve its components, especially in the presence of aggressive carbon dioxide; this can give the water an unpleasant taste (iron, manganese, zinc) or involve a real risk of toxicity (lead, cadmium).
[Regulatory limit for mains water network: between 6.5. and 9.5 (indicator parameter). As for mineral water, the parameter is specified but no limit is set.]
Conductivity
Conductivity is the degree to which a specified substance (conductor) conducts electricity. The higher the concentration of ions, the higher the conductivity.
Therefore, conductivity indicates the degree of mineralization of the water: a high value shows the water is rich in salts, whereas a low value indicates it is mineral-poor. There may be a correlation between this parameter and dry residue. Since conductivity also depends on temperature, a conventional reference value of 20 °C has been established.
[Legally defined indicator parameter for mains water network, the recommended value is less than 2,500 µScm-1 at 20 °C. As for mineral water, the parameter is specified but no limit is set.]
Hardness
Hardness indicates the presence of calcium and magnesium salts dissolved in the water. It is measured in French degrees (°F). Each degree corresponds to 10 mg/l of calcium carbonate. One possible hardness scale defines "soft" waters as having 15-20 °F, "medium hard" waters 20-35 °F and "hard" waters more than 35 °F.
It may be medically advisable to drink waters with certain degrees of hardness. Usually, the calcium found in water is beneficial for health. In fact, where domestic water softeners are installed, the law prohibits lowering hardness below 15 °F. On the other hand, it is well-known that water which is too hard damages household appliances and sanitaryware, which explains why many detergents contain anti-limescale substances.
[Legal indicator parameter for mains water network. The recommended maximum value is 50 °F. As for waters subject to softening or desalinisation processes, the lower limit is 15 °F. As for mineral water, the parameter is not specified.]
Escherichia coli
This is one of the main bacterial species that lives in warm-blooded animals' intestines. The presence of Escherichia coli in water is an “indicator” of faecal contamination.
[Regulatory limit for mains water network: 0/100 mL (microbiological parameter). As for mineral water, the parameter must "be absent".]
Iron
This metal is one of the main components of the Earth's crust. It may be present in drinking water as well, as the result of the flocculants used in drinking water treatment plants or of the corrosion of steel/cast iron pipes during water distribution. Iron is deemed an undesirable element as even at a concentration of about 0.3 mg/l it makes the water look yellow and gives it an unpleasant, metallic taste.
[Regulatory limit for mains water network: 200 µg/L (indicator parameter). As for mineral water, the parameter is specified but no limit is set.]
Fluoride
It expresses fluoride content. Fluoride is indispensable, especially for teeth and bones, and should be assumed in small quantities. Excessive amounts can have a negative effect on skeleton and dentition.
[Regulatory limit for mains water network: 1.50 mg/l (chemical parameter). As for mineral water, 5 mg/l and 1.5 mg/l for water intended for infants.]
Magnesium
Magnesium accounts for about 2% of the Earth's crust and is the third most abundant element dissolved in sea water. In nature, it does not exist in a free state but is bound to other elements. Magnesium is responsible for numerous essential metabolic processes such as the formation of urea, the transmission of muscular impulses, nervous transmission, and cellular electric stability.
[No regulatory limit is set for mains water network. As for mineral water, the parameter is specified but no limit is set.]
Manganese
It is a common, naturally occurring chemical element. This micro-nutrient is assumed daily as part of a balanced diet. It is found in both surface and aquifer waters. If present in quantities that exceed regulations, it can have undesirable effects on drinking water. In fact, manganese alters the organoleptic qualities of water: colour, unpleasant taste and cloudiness.
[Regulatory limit for mains water network: 50 µg/L (indicator parameter). As for mineral water, the limit is 500 µg/L.]
Nitrate and Nitrite
Nitrates and nitrites are pollutant substances. Nitrites and nitrates naturally occur in water in minimal quantities only: in most cases, their presence depends on human activities such as animal breeding, fertilizers, industrial waste, urban waste, and effluent.
[Nitrate: Regulatory limit for mains water network: 50 mg/l (chemical parameter). As for mineral water, 45 mg/l and 10 mg/l for water intended for infants.]
[Nitrite: Regulatory limit for mains water network: 0.50 mg/l (chemical parameter). As for mineral water, the limit is 0.02 mg/l.]
Potassium
Potassium is an alkaline metal found in nature that binds with other elements in water and in other minerals. While it may exist naturally in the environment, its presence is increased by agricultural practices.
[No regulatory limit is set for mains water network. As for mineral water, the parameter is specified but no limit is set.]
Lead
Lead is a quite common metal. In the past, lead piping was used extensively in mains water systems and as a sealing material along distribution systems. The Istituto Superiore di Sanità (Italian National Higher Institute of Health) has conducted an in-depth study into the risk of contamination where water comes into contact with lead piping. The study found this aspect to be of little relevance in Italy.
[Regulatory limit for mains water network: 10 µg/L (chemical parameter). As for mineral water, the limit is 10 µg/L.]
Dry residue at 180°
Drinking waters and mineral waters can contain high, medium, or low levels of salts - mostly carbonates, bicarbonates, chlorides, and sulphates, - combined with sodium, potassium, calcium and magnesium. Dry or fixed residue indicates the quantity of dissolved salts in waters after the evaporation of a litre of water at 180°; the lower the quantity, the less salt it contains - and vice versa. Up to 50 mg/l, water is only minimally mineralised i.e. it is poor in salts, aiding diuresis and helping prevent/treat kidney stones. Values from 50 to 500 mg/l give a 'low mineralised or 'lightly mineralised' water that is suitable for daily consumption and has a good diuretic action. From 500 to 1,500 mg/l water may be defined as averagely mineralised, suitable for persons who practice sport. Beyond 1,500 mg/l, water is salt-rich and suitable for medical treatment where advised by a doctor.
[Indicator parameter for mains water network with recommended maximum value 1,500 mg/l. As for mineral water, the parameter is specified but no limit is set.]
Sodium
Sodium is abundant in nature and therefore present, in varying quantities, in all natural waters as sodium chloride (common salt) and sodium bicarbonate. Sodium content in Hera-supplied waters is comparable to that of bottled mineral water.
In terms of total dietary requirements, the amount of sodium in water is generally irrelevant: for example, drinking a litre of tap water is the equivalent of eating little more than half a cracker. Most ingested sodium (i.e. salt) comes from foods. Water plays a negligible role.
[Regulatory limit for mains water network: 200 mg/l (indicator parameter). As for mineral water, the parameter is specified but no limit is set.]
Sulphate
Sulphates are sulphuric acid salts, most of which are soluble in water. They are present in nature in varying minerals, hence their presence in water. Sulphates can alter the taste of water. Moreover, excess amounts can corrode distribution piping/systems.
[Regulatory limit for mains water network: 250 mg/l (indicator parameter). As for mineral water, the parameter is specified but no limit is set.]
Tetrachloroethylene + Trichloroethylene (Trichloroethene)
These two chemical compounds are found in water as a result of the ground/underground contamination caused by illicit industrial activities.
[Regulatory limit for mains water network: 10 µg/L (chemical parameter). As for mineral water, the parameter must not "be detectable with methods that have the lower analytical efficiency limits" defined by law.]
Trihalomethanes-Total
One of the best-known by-products of disinfection: their presence in drinking water is linked to the use of sodium hypochlorite as a disinfectant. Trihalomethanes are formed by natural organic substances in water reacting with sodium hypochlorite.
[Regulatory limit for mains water network: 30 µg/L (chemical parameter). As for mineral water, the parameter must not "be detectable with methods that have the lower analytical efficiency limits" defined by law.]