Water Contaminants - Part 2
Water Contaiminants- Part 2
Brief information
limits of contaiminants for safe drinking water and Health effects
7- Helium (He) and water
Helium as a noble gas and after hydrogen, it is the most prevalent element in the universe that is 5 ppm in the atmosphere, 4-7 ppt in sea water and usually do not react with any other particles.
As it does not react with water or any particles, but can produce non-stable compounds as VHe3+ and HePtHe2+.
Helium is the most less soluble in water that is 1.5mg/l at 20oc at I bar pressure.
Helium used as a coolant for nuclear reactors, applied as gas lasers, used as a protective coating, remain in liquid below -269oc. helium E939 used as food additive.
Uranium minerals contain small amounts of helium. Helium may escape through splits in the earth's crust. However, it does not end up in water directly and used to find leaks, nuclear weapon testing, to determine radioactivity and water contamination
3He isotope tritium accumulates in water but does not escape to the atmosphere.
Although it does not dissolve in water but still a very small amount present in water, it not a dietary mineral of any organism.
2 helium isotopes non-radioactive and 6 unstable isotopes exist.
It is not a dietary mineral fo5r human being and a very small amount found in the human body and does not play any role in the human body and no toxic.
Helium gas harmless when inhaled small quantity but if large quantity inhaled force oxygen to go away and so asphyxia may cause.
Helium is not a water contaminant so no need for purifying technique.
8- Iodine (I) and water
Iodine is naturally present in water. The concentration in seawater varies from Place to place an average is about 60 ppb. In rivers about 5 ppb. In brown algae, iodine found up to 0.45%. In corals, sea sponges, shells and fishes high concentration of iodine found as thyroxin or tri-iodine thyroxin.
Reaction of iodine with water
Iodine is strongly reactive but less than other halogens. It is not found as an element, but as I2 molecules, as I- ions, or as iodate salt as IO3-.
Iodine mix with water as:
I2(l) + H2O(l) -> OI-(aq) + 2H+(aq) + I-(aq)
I2 molecules as hypoiodite (OI-) with water molecules react to any substance in equilibrium depending on the pH of the solution.
It also occurs as I3-(aq), HIO(aq), IO-(aq) en HIO3(aq) and can combine to many different substances, for example, other halogens and behave differently when mixing with water.
The solubility of iodine and its compounds:
The solubility of iodine in water depends on temperature (20oC) and pressure (1 bar) and is relatively low.
mechanism occurs as: I2 + I- -> [I3]-
Iodine mix with water escape from the surface as iodine gas. Iodine is soluble.
Iodine naturally presents in surface water by rain and evaporation, also present in groundwater and also by climatic effects on rocks, volcanic and underground volcanic activity.
Naturally, iodine found in large amounts as iodine compounds.
Iodine is applied as iodine x-rays for patients up to maximum dose 200 gm, and drain through urine and finally add to groundwater by wastewater discharge. It is also used for cleaning and disinfecting wounds, and also used in facial soap, and band-aids. It is also used Paint industries, photographic chemicals, batteries, lubricants. Radioactive iodine used in medicines like thyroid cancer treatment. It can be released from a nuclear accident, finally, end up in surface water by the discharge of water treatment plant including radioactive isotopes it retain in sludge for 2 - 25%
Environmental effects
It is water hazard class 1 means slightly harmful when dissolved in water. Reaction with alkali metals, aluminium, mercury, fluorine or turpentine may enhance the risk
Environmental risks may differ between iodine substances.
The LD50 value for oral uptake for rats is about 14,000 mg/kg.
Radioactive iodine in excessive amount like isotope 131 as evolved during Chernobyl in 1086 give hazardous environmental impact. The half-life of this isotope is 8 days and mostly uptake by cows and other cattle transferring to milk and other water supplies. High tide erases radioactive iodine. Normally, human hardly come into contact with radioactive iodine unless the places nearby some related work nearby and then certainly need medical treatment
Health effects of iodine in water:
The human body contains about 10 - 15 mg and a larger amount can be found in the thyroid gland. Daily intake recommended is 150 and 200 μg getting from iodine salts in the kitchen.
Iodine uptake differs in different people worldwide, people eating a large amount of fish uptake large amount of iodine that is between 50 μg and 10 mg per day.
Iodine negatively influences the thyroid gland associated with hyperactivity. illness involving symptoms such as inches, bronchitis, sleep disorders, rashes, etc, after long-term exposure. contact of iodine with skin may pigmentation. Its fumes cause eye and lung irritation.
Pure iodine is a toxic, even smaller amount as 2 g may be lethal. Alcoholic solution an amount of 30 ml may be lethal. Iodines are relatively harmless in comparison. However, female fertility as found by the experiment on the rat is influenced by iodine.
Children react fiercely to increased or decreased iodine uptake because the thyroid gland is developing.
Activated carbon can be used to remove iodine from water.
Its primary application in drinking water is disinfection. Iodine tablets that may be added directly to water can be obtained.
9. Iron (Fe) and water
Iron and water: reaction mechanisms, environmental impact and health effects
Iron in seawater is around 1-3 ppb but it varies in different areas like in Atlantic and Pacific ocean and other rivers iron present about 0.5 - 1.00 ppm. maximum iron found in groundwater that is 100 ppm. Drinking water permissible limit is 200 ppb.
Algae contain 20 - 200 ppm of iron, In brown algae may be up to 4000 ppm. In seawater is approximately 104 - 105. Sea fish contain about 10-90 ppm. Oyster tissue contains about 195 ppm of iron (all are dry mass).
Iron present as Fe(OH)2 in acidic to the neutral solution and oxygen-rich condition Iron is part of many organic and inorganic chelation complexes that are generally water soluble.
Iron corrodes in moist air (containing water and oxygen) as hydrated oxides in reddish brown colour. the reaction s are as under:
4 Fe + 3 O2 + 6 H2O -> 4 Fe3+ + 12 OH- -> 4 Fe(OH)3 or 4 FeO(OH) + 4 H2O
The oxide layer does not stop any further corrosion and keep on oxidation process and in presence of atmospheric SO2, it also forms iron sulphate like in sea water.
Iron occurs as iron oxide, iron hydroxide, iron carbide and iron pentacarbonyl are water-insoluble, solubility depends on the acidity of the solution that is lower pH.
Soluble iron compounds like Iron carbonate solubility 60mg/l, iron sulphate 6 mg/l, Iron vitrol 295 g/l, Iron chelates mostly water soluble
Iron compounds like Fe2+ are soluble in slightly acidic solution but Fe3+ compounds are soluble in strongly acidic solutions, but water solubility increases when these are reduced to Fe2+ under certain conditions.
Iron present naturally occurs as magnetite, hematite, goethite and siderite. due to weather effects, iron enters into the water. in drinking and mineral water it is present as an iron carbonate.
Worldwide iron being produced about 500 million tons annually, in which 300 tons are recycled. Iron alloys being produced due to protect from corrosion and are being used in containers, cars, laundry machines, bridges, buildings, and in springs. other uses are in the glass industry, pharmaceutical industry, chemical, iron fertilizer or pesticides and also in wood presentation and photography.
Aluminium waste containing iron discharged are applied as soil fillers.
To remove compounds from water in water purification processes. The 59Fe isotope is applied in medical research and nuclear physics.
In most of the organisms, iron as a dietary requirement plays an important role in natural processes in a binary and tertiary form. Oxidized tertiary iron be used in organisms freely, except at low pH values. Still, iron usually occurs in water-insoluble form.
Soluble iron increases productivity in oceanic surface layers it plays an important role in the carbon cycle. It is essential for nitrogen binding and reduction, and it may be a limiting factor for phytoplankton growth. Solubility in salt water is extremely low.
In iron cycle reduction of tertiary iron by organic ligands (a process that is photo catalysed in surface waters), and oxidation of binary iron.
Iron complexes that often play an important role in nature, such as haemoglobin, a red colouring agent in blood that binds and releases oxygen in breathing processes.
Organisms use binary iron than of tertiary iron, and uptake depends on the saturation of physical iron reserves.
Iron is a limiting factor for water organisms in surface layers. When complex iron is absent, water-insoluble tertiary iron hydroxides precipitate which is not hazardous for aquatic life, because not much is known about hazards of waterborne iron.
Molluscs have teeth of magnetite of goethite.
Green plants cause energy transformation in presence of iron. Plants are animal feed containing up to 1000 ppm of iron, but much less in the plants used by the human. Plants contain between 20 and 300 ppm iron (dry mass), but lichens up to 5.5% of iron. When soils contain little iron or little water-soluble iron, plants may have growth problems. Plant uptake varies, depending on soil iron concentrations and pH values, phosphate concentrations and iron and other heavy metals. Limes soils are often iron deficit, even when sufficient amounts of iron are present due to high pH value, which leads to iron precipitation.
Iron present in soils in tertiary form, but it is converted to binary iron in water saturated enabling plant iron uptake. Water-insoluble iron compounds releasing H+ ions, causing it to dissolve. Microorganisms release iron siderochrome, which can be directly taken up by plants.
Iron may be harmful to plants between 5 and 200 ppm. These cannot be found in nature under normal conditions when low amounts of soil water are present.
Many bacteria take up iron particles and convert to magnetite. Iron compounds may cause a much more serious environmental impact than the element itself. A number of LD50 values are known for rats (oral intake): iron (III) acetylacetonate 1872 mg/kg, iron (II) chloride 984 mg/kg, and iron pentacarbonyl 25 mg/kg.
There are four natural non-radioactive iron isotopes. There are eight instable iron isotopes.
Health effects of iron in the water
The human body contains about 4 g, 70% is present in red blood as colouring agents. It is a dietary requirement for humans and many other organisms. Men need 7 mg iron, whereas women require 11 mg. on a daily basis. The difference is because of menstrual cycles. When people feed the iron amounts can be obtained rapidly. The body absorbs about 25% of all iron from the food, this percentage may increase when someone has iron deficit feed iron intake by means of vitamin C tablets which reduces tertiary iron to binary iron. Phosphates and phytates decrease the amount of binary iron.
Binary iron bound to haemoglobin and myoglobin, or as tertiary iron. The body may particularly absorb the binary form of iron.
Iron is the main component of haemoglobin. It combines oxygen and transports it from lungs to other body parts and transports CO2 back to the lungs, where it can be breathed out. Oxygen storage also requires iron. It is an essential part of several enzymes and is involved in DNA synthesis. Normal brain functions are iron dependent.
Iron is strongly bound to transferrin enabling an exchange of the metal between cells. The compound is a strong antibiotic preventing bacteria from growing on the vital element. When one is infected by bacteria, the body produces high amounts of transferrin.
When iron exceeds it is stored in the liver. The bone marrow contains high amounts of iron because it produces haemoglobin.
Iron deficiency causes anaemia, tiredness, headaches and loss of concentration. The immunity also affected. In young children, it affects mental development, leads to irritability, and causes concentration disorder. Young children, pregnant women and women in their period are often treated with iron (II) salts upon iron deficits.
When excess iron is absorbed, by haemochromatosis patients, iron is stored in the pancreas, the liver, the spleen and the heart. and may damage vital organs. Healthy people are generally not affected by overdose and generally rare. It may occur when one drinks water with iron concentrations over 200 ppm.
Water-soluble binary iron compounds such as FeCl2 and FeSO4 are toxic exceeding 200 mg concentration, and lethal for adults upon doses of 10-50 g. A number of iron chelates may be toxic, and the nerve toxin iron pentacarbonyl is known for its strong toxic mechanism. Iron dust may cause lung disease.
Removal of iron from water?
Iron removal from water is necessary for drinking water because it influences water colour, odour and turbidity.
To speed up the reaction under acidic conditions, the water may be aerated for carbon dioxide removal and pH recovery. The total reaction causes acid formation and thereby diminishes itself. Iron is often reduced together with manganese.
Applying ion exchangers for iron trace removal from drinking water and process water is another option, but not suitable for high iron removal.
Iron compounds are applied in wastewater treatment, usually as coagulants. One example is iron sulphate application in phosphate removal.
10. Lead (Pb) and water.
lead found in seawater in traces that is 2-30 ppt. In rivers 3-30 ppb
5-10 ppm in Phytoplankton as dry mass, 0.5 1000 ppb in freshwater fish, 500 ppb in the oyster.
As per WHO the legal limits were 50 ppb in 1995 and later decreased to10 ppb in 2010.
Normally lead does not react with water but when comes in contact with moist air, the reaction increases and a thin lead oxide layer is formed at the surface. In presence of water and air, lead hydroxide (Pb(OH)2) is formed. see as follows:
2Pb + O2 + 2H2O -> 2 Pb(OH)2
As lead is insoluble in water up to 20oC, and pressure up to 1 bar.but anyway when dissolving in water as PbCO3 or Pb(CO3)22. water-soluble lead sugar is lead (ll)acetate which is sweet in nature. It combines with sulphur as S2- and phosphorous as PO43- which are extremely insoluble. Lead compounds are soluble in soft and slightly acidic water.
Lead in water
Lead waterworks were often applied in former days, and these may still be present in old buildings. Lead enters or dissolves in water through pipes particularly when water flowing is hard water forming lead carbonates. A hardly soluble alkalic lead carbonate is formed on the surface as a layer which acts as a protective layer for pipes. In old days Romans fill the pipes with wine to dissolve this layer and form lead sugar (lead acetate) and was being used to sweeten wine, beverages and foodstuffs despite of its toxicity
Lead pollution is common near mining industries containing lead compounds in lead ores and found its health effects. It is also found as a by-product in silver mining.
Alkalic lead carbonate (2PbCO3.Pb(OH)2) called as lead white used as a white pigment but because of its toxicity, it is prohibited in the European Union.
Organic lead is being used in petroleum, and inorganic lead used in the battery and paint production. Also used in computer and TV screens
Tetra-ethyl lead is being used as an additive in fuels. This organic lead converted to inorganic lead and ends up in water, sometimes even in drinking water. This form is less and less abundant.
In the construction field, it is used in roofs and in stained glass windows. In Lead in food causes about half of the human lead exposure.
Effects of lead in water.
As toxic pollutants. Lead(II)salts and organic lead compounds are ecotoxicological. Lead salts like lead acetate, lead oxide, lead nitrate, and lead carbonate are water hazard class 2, and very harmful.
Lead involves in chlorophyll synthesis and can take up high levels of lead up to 500 ppm from soils. High concentrations in plants growth influence negatively. Through plant uptake, lead enters in food chains by plant uptake. The lead pesticide is prohibited in most countries. Lead accumulates in organisms, sediments and sludge. Lead in wastewater mostly stems from streets and roofs.
Lead has four stable isotopes and 26 unstable isotopes.
Health effects of lead in water
The human body contains about 120 mg of lead. 10-20% is absorbed by the intestines. Overexposure to lead include colics, skin pigmentation and paralysis. Effects of lead poisoning are neurological or teratogenic. Organic lead causes necrosis of neurons. Inorganic lead causes axonal degeneration and demyelination. Lead may cause cerebral oedema and congestion. Organic lead compounds absorb quicker and pose a greater risk. Organic lead derivates may be carcinogenic. Lead poisoning effects on women are more than men. In women, the lead may cause menstrual disorder, infertility and spontaneous abortion, and the risk of stillbirth. Foetuses are more than mothers, and even protect mothers from lead poisoning. earlier it was applied for birth control, like a spermicidal, and to induce abortion.
Children absorb more than adults (up to 40%) and are more susceptible to lead poisoning than adults in the form of lower IQs and concentration disorder.
Lead accumulates in leg tissue and lead poisoning causes encephalopathy.
Lead toxicity by lead ions reacting with free sulfhydryl groups of proteins, like enzymes deactivation and may interact with other metal ions.
Purification technologies to purify water:
Purification can be performed by coagulation, sand filtration and ion exchange. Activated carbon, media filtration and reverse Osmosis can also be applied for purification.
This is the end of Part two. Come back later for the next Part.
I was able to gather all this information with the help of Lenntech.
Brief information
limits of contaiminants for safe drinking water and Health effects
7- Helium (He) and water
Helium as a noble gas and after hydrogen, it is the most prevalent element in the universe that is 5 ppm in the atmosphere, 4-7 ppt in sea water and usually do not react with any other particles.
As it does not react with water or any particles, but can produce non-stable compounds as VHe3+ and HePtHe2+.
Helium is the most less soluble in water that is 1.5mg/l at 20oc at I bar pressure.
Helium used as a coolant for nuclear reactors, applied as gas lasers, used as a protective coating, remain in liquid below -269oc. helium E939 used as food additive.
Uranium minerals contain small amounts of helium. Helium may escape through splits in the earth's crust. However, it does not end up in water directly and used to find leaks, nuclear weapon testing, to determine radioactivity and water contamination
3He isotope tritium accumulates in water but does not escape to the atmosphere.
Although it does not dissolve in water but still a very small amount present in water, it not a dietary mineral of any organism.
2 helium isotopes non-radioactive and 6 unstable isotopes exist.
It is not a dietary mineral fo5r human being and a very small amount found in the human body and does not play any role in the human body and no toxic.
Helium gas harmless when inhaled small quantity but if large quantity inhaled force oxygen to go away and so asphyxia may cause.
Helium is not a water contaminant so no need for purifying technique.
8- Iodine (I) and water
Iodine is naturally present in water. The concentration in seawater varies from Place to place an average is about 60 ppb. In rivers about 5 ppb. In brown algae, iodine found up to 0.45%. In corals, sea sponges, shells and fishes high concentration of iodine found as thyroxin or tri-iodine thyroxin.
Reaction of iodine with water
Iodine is strongly reactive but less than other halogens. It is not found as an element, but as I2 molecules, as I- ions, or as iodate salt as IO3-.
Iodine mix with water as:
I2(l) + H2O(l) -> OI-(aq) + 2H+(aq) + I-(aq)
I2 molecules as hypoiodite (OI-) with water molecules react to any substance in equilibrium depending on the pH of the solution.
It also occurs as I3-(aq), HIO(aq), IO-(aq) en HIO3(aq) and can combine to many different substances, for example, other halogens and behave differently when mixing with water.
The solubility of iodine and its compounds:
The solubility of iodine in water depends on temperature (20oC) and pressure (1 bar) and is relatively low.
mechanism occurs as: I2 + I- -> [I3]-
Iodine mix with water escape from the surface as iodine gas. Iodine is soluble.
Iodine naturally presents in surface water by rain and evaporation, also present in groundwater and also by climatic effects on rocks, volcanic and underground volcanic activity.
Naturally, iodine found in large amounts as iodine compounds.
Iodine is applied as iodine x-rays for patients up to maximum dose 200 gm, and drain through urine and finally add to groundwater by wastewater discharge. It is also used for cleaning and disinfecting wounds, and also used in facial soap, and band-aids. It is also used Paint industries, photographic chemicals, batteries, lubricants. Radioactive iodine used in medicines like thyroid cancer treatment. It can be released from a nuclear accident, finally, end up in surface water by the discharge of water treatment plant including radioactive isotopes it retain in sludge for 2 - 25%
Environmental effects
It is water hazard class 1 means slightly harmful when dissolved in water. Reaction with alkali metals, aluminium, mercury, fluorine or turpentine may enhance the risk
Environmental risks may differ between iodine substances.
The LD50 value for oral uptake for rats is about 14,000 mg/kg.
Radioactive iodine in excessive amount like isotope 131 as evolved during Chernobyl in 1086 give hazardous environmental impact. The half-life of this isotope is 8 days and mostly uptake by cows and other cattle transferring to milk and other water supplies. High tide erases radioactive iodine. Normally, human hardly come into contact with radioactive iodine unless the places nearby some related work nearby and then certainly need medical treatment
Health effects of iodine in water:
The human body contains about 10 - 15 mg and a larger amount can be found in the thyroid gland. Daily intake recommended is 150 and 200 μg getting from iodine salts in the kitchen.
Iodine uptake differs in different people worldwide, people eating a large amount of fish uptake large amount of iodine that is between 50 μg and 10 mg per day.
Iodine negatively influences the thyroid gland associated with hyperactivity. illness involving symptoms such as inches, bronchitis, sleep disorders, rashes, etc, after long-term exposure. contact of iodine with skin may pigmentation. Its fumes cause eye and lung irritation.
Pure iodine is a toxic, even smaller amount as 2 g may be lethal. Alcoholic solution an amount of 30 ml may be lethal. Iodines are relatively harmless in comparison. However, female fertility as found by the experiment on the rat is influenced by iodine.
Children react fiercely to increased or decreased iodine uptake because the thyroid gland is developing.
Activated carbon can be used to remove iodine from water.
Its primary application in drinking water is disinfection. Iodine tablets that may be added directly to water can be obtained.
9. Iron (Fe) and water
Iron and water: reaction mechanisms, environmental impact and health effects
Iron in seawater is around 1-3 ppb but it varies in different areas like in Atlantic and Pacific ocean and other rivers iron present about 0.5 - 1.00 ppm. maximum iron found in groundwater that is 100 ppm. Drinking water permissible limit is 200 ppb.
Algae contain 20 - 200 ppm of iron, In brown algae may be up to 4000 ppm. In seawater is approximately 104 - 105. Sea fish contain about 10-90 ppm. Oyster tissue contains about 195 ppm of iron (all are dry mass).
Iron present as Fe(OH)2 in acidic to the neutral solution and oxygen-rich condition Iron is part of many organic and inorganic chelation complexes that are generally water soluble.
Iron corrodes in moist air (containing water and oxygen) as hydrated oxides in reddish brown colour. the reaction s are as under:
4 Fe + 3 O2 + 6 H2O -> 4 Fe3+ + 12 OH- -> 4 Fe(OH)3 or 4 FeO(OH) + 4 H2O
The oxide layer does not stop any further corrosion and keep on oxidation process and in presence of atmospheric SO2, it also forms iron sulphate like in sea water.
Iron occurs as iron oxide, iron hydroxide, iron carbide and iron pentacarbonyl are water-insoluble, solubility depends on the acidity of the solution that is lower pH.
Soluble iron compounds like Iron carbonate solubility 60mg/l, iron sulphate 6 mg/l, Iron vitrol 295 g/l, Iron chelates mostly water soluble
Iron compounds like Fe2+ are soluble in slightly acidic solution but Fe3+ compounds are soluble in strongly acidic solutions, but water solubility increases when these are reduced to Fe2+ under certain conditions.
Iron present naturally occurs as magnetite, hematite, goethite and siderite. due to weather effects, iron enters into the water. in drinking and mineral water it is present as an iron carbonate.
Worldwide iron being produced about 500 million tons annually, in which 300 tons are recycled. Iron alloys being produced due to protect from corrosion and are being used in containers, cars, laundry machines, bridges, buildings, and in springs. other uses are in the glass industry, pharmaceutical industry, chemical, iron fertilizer or pesticides and also in wood presentation and photography.
Aluminium waste containing iron discharged are applied as soil fillers.
To remove compounds from water in water purification processes. The 59Fe isotope is applied in medical research and nuclear physics.
In most of the organisms, iron as a dietary requirement plays an important role in natural processes in a binary and tertiary form. Oxidized tertiary iron be used in organisms freely, except at low pH values. Still, iron usually occurs in water-insoluble form.
Soluble iron increases productivity in oceanic surface layers it plays an important role in the carbon cycle. It is essential for nitrogen binding and reduction, and it may be a limiting factor for phytoplankton growth. Solubility in salt water is extremely low.
In iron cycle reduction of tertiary iron by organic ligands (a process that is photo catalysed in surface waters), and oxidation of binary iron.
Iron complexes that often play an important role in nature, such as haemoglobin, a red colouring agent in blood that binds and releases oxygen in breathing processes.
Organisms use binary iron than of tertiary iron, and uptake depends on the saturation of physical iron reserves.
Iron is a limiting factor for water organisms in surface layers. When complex iron is absent, water-insoluble tertiary iron hydroxides precipitate which is not hazardous for aquatic life, because not much is known about hazards of waterborne iron.
Molluscs have teeth of magnetite of goethite.
Green plants cause energy transformation in presence of iron. Plants are animal feed containing up to 1000 ppm of iron, but much less in the plants used by the human. Plants contain between 20 and 300 ppm iron (dry mass), but lichens up to 5.5% of iron. When soils contain little iron or little water-soluble iron, plants may have growth problems. Plant uptake varies, depending on soil iron concentrations and pH values, phosphate concentrations and iron and other heavy metals. Limes soils are often iron deficit, even when sufficient amounts of iron are present due to high pH value, which leads to iron precipitation.
Iron present in soils in tertiary form, but it is converted to binary iron in water saturated enabling plant iron uptake. Water-insoluble iron compounds releasing H+ ions, causing it to dissolve. Microorganisms release iron siderochrome, which can be directly taken up by plants.
Iron may be harmful to plants between 5 and 200 ppm. These cannot be found in nature under normal conditions when low amounts of soil water are present.
Many bacteria take up iron particles and convert to magnetite. Iron compounds may cause a much more serious environmental impact than the element itself. A number of LD50 values are known for rats (oral intake): iron (III) acetylacetonate 1872 mg/kg, iron (II) chloride 984 mg/kg, and iron pentacarbonyl 25 mg/kg.
There are four natural non-radioactive iron isotopes. There are eight instable iron isotopes.
Health effects of iron in the water
The human body contains about 4 g, 70% is present in red blood as colouring agents. It is a dietary requirement for humans and many other organisms. Men need 7 mg iron, whereas women require 11 mg. on a daily basis. The difference is because of menstrual cycles. When people feed the iron amounts can be obtained rapidly. The body absorbs about 25% of all iron from the food, this percentage may increase when someone has iron deficit feed iron intake by means of vitamin C tablets which reduces tertiary iron to binary iron. Phosphates and phytates decrease the amount of binary iron.
Binary iron bound to haemoglobin and myoglobin, or as tertiary iron. The body may particularly absorb the binary form of iron.
Iron is the main component of haemoglobin. It combines oxygen and transports it from lungs to other body parts and transports CO2 back to the lungs, where it can be breathed out. Oxygen storage also requires iron. It is an essential part of several enzymes and is involved in DNA synthesis. Normal brain functions are iron dependent.
Iron is strongly bound to transferrin enabling an exchange of the metal between cells. The compound is a strong antibiotic preventing bacteria from growing on the vital element. When one is infected by bacteria, the body produces high amounts of transferrin.
When iron exceeds it is stored in the liver. The bone marrow contains high amounts of iron because it produces haemoglobin.
Iron deficiency causes anaemia, tiredness, headaches and loss of concentration. The immunity also affected. In young children, it affects mental development, leads to irritability, and causes concentration disorder. Young children, pregnant women and women in their period are often treated with iron (II) salts upon iron deficits.
When excess iron is absorbed, by haemochromatosis patients, iron is stored in the pancreas, the liver, the spleen and the heart. and may damage vital organs. Healthy people are generally not affected by overdose and generally rare. It may occur when one drinks water with iron concentrations over 200 ppm.
Water-soluble binary iron compounds such as FeCl2 and FeSO4 are toxic exceeding 200 mg concentration, and lethal for adults upon doses of 10-50 g. A number of iron chelates may be toxic, and the nerve toxin iron pentacarbonyl is known for its strong toxic mechanism. Iron dust may cause lung disease.
Removal of iron from water?
Iron removal from water is necessary for drinking water because it influences water colour, odour and turbidity.
To speed up the reaction under acidic conditions, the water may be aerated for carbon dioxide removal and pH recovery. The total reaction causes acid formation and thereby diminishes itself. Iron is often reduced together with manganese.
Applying ion exchangers for iron trace removal from drinking water and process water is another option, but not suitable for high iron removal.
Iron compounds are applied in wastewater treatment, usually as coagulants. One example is iron sulphate application in phosphate removal.
10. Lead (Pb) and water.
lead found in seawater in traces that is 2-30 ppt. In rivers 3-30 ppb
5-10 ppm in Phytoplankton as dry mass, 0.5 1000 ppb in freshwater fish, 500 ppb in the oyster.
As per WHO the legal limits were 50 ppb in 1995 and later decreased to10 ppb in 2010.
Normally lead does not react with water but when comes in contact with moist air, the reaction increases and a thin lead oxide layer is formed at the surface. In presence of water and air, lead hydroxide (Pb(OH)2) is formed. see as follows:
2Pb + O2 + 2H2O -> 2 Pb(OH)2
As lead is insoluble in water up to 20oC, and pressure up to 1 bar.but anyway when dissolving in water as PbCO3 or Pb(CO3)22. water-soluble lead sugar is lead (ll)acetate which is sweet in nature. It combines with sulphur as S2- and phosphorous as PO43- which are extremely insoluble. Lead compounds are soluble in soft and slightly acidic water.
Lead in water
Lead waterworks were often applied in former days, and these may still be present in old buildings. Lead enters or dissolves in water through pipes particularly when water flowing is hard water forming lead carbonates. A hardly soluble alkalic lead carbonate is formed on the surface as a layer which acts as a protective layer for pipes. In old days Romans fill the pipes with wine to dissolve this layer and form lead sugar (lead acetate) and was being used to sweeten wine, beverages and foodstuffs despite of its toxicity
Lead pollution is common near mining industries containing lead compounds in lead ores and found its health effects. It is also found as a by-product in silver mining.
Alkalic lead carbonate (2PbCO3.Pb(OH)2) called as lead white used as a white pigment but because of its toxicity, it is prohibited in the European Union.
Organic lead is being used in petroleum, and inorganic lead used in the battery and paint production. Also used in computer and TV screens
Tetra-ethyl lead is being used as an additive in fuels. This organic lead converted to inorganic lead and ends up in water, sometimes even in drinking water. This form is less and less abundant.
In the construction field, it is used in roofs and in stained glass windows. In Lead in food causes about half of the human lead exposure.
Effects of lead in water.
As toxic pollutants. Lead(II)salts and organic lead compounds are ecotoxicological. Lead salts like lead acetate, lead oxide, lead nitrate, and lead carbonate are water hazard class 2, and very harmful.
Lead involves in chlorophyll synthesis and can take up high levels of lead up to 500 ppm from soils. High concentrations in plants growth influence negatively. Through plant uptake, lead enters in food chains by plant uptake. The lead pesticide is prohibited in most countries. Lead accumulates in organisms, sediments and sludge. Lead in wastewater mostly stems from streets and roofs.
Lead has four stable isotopes and 26 unstable isotopes.
Health effects of lead in water
The human body contains about 120 mg of lead. 10-20% is absorbed by the intestines. Overexposure to lead include colics, skin pigmentation and paralysis. Effects of lead poisoning are neurological or teratogenic. Organic lead causes necrosis of neurons. Inorganic lead causes axonal degeneration and demyelination. Lead may cause cerebral oedema and congestion. Organic lead compounds absorb quicker and pose a greater risk. Organic lead derivates may be carcinogenic. Lead poisoning effects on women are more than men. In women, the lead may cause menstrual disorder, infertility and spontaneous abortion, and the risk of stillbirth. Foetuses are more than mothers, and even protect mothers from lead poisoning. earlier it was applied for birth control, like a spermicidal, and to induce abortion.
Children absorb more than adults (up to 40%) and are more susceptible to lead poisoning than adults in the form of lower IQs and concentration disorder.
Lead accumulates in leg tissue and lead poisoning causes encephalopathy.
Lead toxicity by lead ions reacting with free sulfhydryl groups of proteins, like enzymes deactivation and may interact with other metal ions.
Purification technologies to purify water:
Purification can be performed by coagulation, sand filtration and ion exchange. Activated carbon, media filtration and reverse Osmosis can also be applied for purification.
This is the end of Part two. Come back later for the next Part.
I was able to gather all this information with the help of Lenntech.
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