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Heavy metals (heavy metals) group of metals (40 elements) that the manufacturer of natural earth and have a density greater than 5.
Contaminants that are found in water, resulting from domestic wastewater discharge, chemical products, pesticides, insecticides and herbicides, industrial discharge, radioactive waste, petroleum hydrocarbons and color.
In terms of ecological, biodegradable and non-polluting contaminants into two types of analysis can be divided. Non-biodegradable pollutants such as heavy metal compounds and salts, long-chain phenolic chemicals, pesticides like DDT are in the environment and accumulate in the food chain in the water affect Vbyvlvzhyky. Increasing concentrations of these chemicals on fish, other aquatic organisms and may have adverse effects on aquatic plants. They produce toxin in combination with any other materials are additional. For example, the combination of heavy metals such as copper, cadmium and zinc, nickel, they redoubled their toxicity.
Heavy metals accumulate in bottom sediments. As a result, ecosystems such as coastal areas of the industrial port with the entrance facing chronic metals, the most contaminated sediments. These features buildups environments, due to the potential toxic effects and bioaccumulation of metals in biological samples of sediments, leading to ecological impacts are high. The effects of metal pollution in an ecosystem, the presence of heavy metals in contaminated biomass is an area that can endanger human health.
Accumulation of heavy metals in water, air and soil, is a major environmental problem. In recent years a number of technologies aimed at reducing or removing heavy metals in contaminated environments have been developed. Among these technologies based on the use of microorganisms, is based were taken into consideration.
◄ biological effects of heavy metals and human health risks
The heavy metals in aquatic systems, Pb, Hg, Cd, Zn, Cu and Ni, respectively. The elements in concentrations greater than the threshold, the organisms, toxic. But some of them (Cu and Zn) in lower concentrations, are essential for metabolism. Set of elements, such as As, Ag, Se, Cr, Al and Sb in freshwater and coastal ecosystems are serious problems in estuaries participate.
In the water column, the heavy metals by phytoplankton, bacteria, fungi and other micro organisms are absorbed. Then, respectively, are eaten by larger animals and humans are the consequences.
When heavy metals used by humans often have detrimental effects and strong. Accumulation of toxic substances, continuous high Ghlztshan and may have the highest frequency in the tissue. Accumulation of toxins in the food chain, the animals may increase the levels of the food chain, it is. A summary of the assembly and the biological effects of heavy metals in marine animals and the possible risk to human health as a result of these metals are listed below:
anionic compound can be seen. The solubility of cadmium in water is influenced by factors such as the composition and pH of the water. More than a few micrograms per liter concentrations of cadmium, cadmium is probably due to the discharge of sewage-polluted waters Bamqadyr less than 1 microgram per liter of cadmium, non-contaminated.
Uptake of cadmium in foodstuffs, methods of animal nutrition, liver and kidney cadmium are a good place to focus, oyster reefs are also high concentrations Azkadmyvm. Cadmium absorption through the skin is very limited. Biological half-life of cadmium in human soft tissue and bone, ten to thirty years. Cadmium, mercury methylation rates in comparison with metals, arsenic, lead, and only very few bacteria called Staphylococcus aureus can methylation Pseudomonas.sp and cadmium, are in an aqueous environment (Who 1984).
Cadmium is found naturally in surface water and groundwater. This element may be in the form of hydrated ions or complex inorganic compounds, such as carbonate, hydroxide, chloride, sulfate and organic compounds with humic acid found. Cadmium from the soil and bedrock erosion, atmospheric pollution from industrial plants, sediments, sewage sludge and manure from infected areas of agriculture, enter the aquatic ecosystem.
Most cadmium to freshwater input, may be rapidly absorbed and suspended matter in aquatic ecosystems be published. Sediments of lakes and rivers, including 9 / 0-2 / 0 and less than 1.0 ppm cadmium in freshwater is. Cd in sediments or water can enter the food chain. Cadmium toxicity to aquatic organisms, may depend on other factors, such as calcium in the water reduces the toxic effects of cadmium. Rivers are polluted with cadmium in agriculture through irrigation, dredging of sediment and runoff can pollute the surrounding area.
Cadmium is a highly toxic metal that causes mortality is small. Serious illness caused by the disease in humans called Aytayy- Aytayy (rheumatoid disease or painful skeletal deformity), respectively. The main toxic effects of cadmium on the lungs, kidneys, bone. Acute effects of exposure, such as bronchitis, pneumonia, and toxicity in the liver. Chronic inhalation of cadmium compounds, in the form of vapor or dust, pulmonary edema, which in this case, the tiny air sacs of the lung grew and eventually destroyed due to low volume. Both chronic inhalation of cadmium uptake by oral secretions that affect the kidneys, the first step in protein excretion by renal proximal tubules.
It seems cadmium, especially the resistance of the host immune resistance against bacteria and viruses decreases. Cadmium may remove mineral skeleton and increased bone fragility and fracture risk.
The acute toxicity of cadmium, may cause death or acute toxicity in aquatic animals and birds make. Cadmium absorbed from the lungs, intestine is more than 50% of cadmium through cigarette smoke inhalation, may be absorbed. The average cadmium concentration in the blood 5-4 times greater in smokers than non-smokers and in all times is 3-2.
The nickel is one of the most popular metals in surface waters. (USEPA 1986). Normally, the primary source of Ni 3: 1) particulate matter in the water 2) the solubility of the rocky bed, 3) the second phase of oil into the surface waters (Eisler 1998). Commercial and industrial use of Ni include stainless steel, plating, painting, ceramics, respectively. Nickel and anthropogenic sources (man-made) into the water systems. The water flows with minimal anthropogenic factors annoying, generally following Ni mg / L 10 is. At the mouth of the Ni concentration of less than mg / L 10, while in the open ocean less than mg / L 7/0 appears. (Jenkins 1980, Eisler 1998) may be the sources of urban pollution levels in mg / L increase 50-10.
In aqueous systems, the nickel salt soluble or absorb with clay particles, organic matter and other substances (Eisler 1998). Nickel may be deposited by sedimentation, of the absorption of clay deposited or stored, or by living organisms (Biota) absorbed. Because microbial activity or changes in physicochemical parameters including pH, ionic strength and concentration, it is possible to reverse the processes of absorption, nickel release from sediments may occur.
According to several symptoms that can be caused by nickel deficiency (mainly in terrestrial vertebrates) and its essential role in various enzymes in bacteria and plants, it is essential that the nickel has been accepted. Nickel necessity of cyanobacteria, algae and aquatic plants related to the metabolism of nickel in the urease and LDH.
Small amounts of nickel to produce red blood cells in the human body is required, although some can be toxic in high doses. Ni seems to not cause problems in the short term but in the long term can cause weight loss, damage to the heart, liver, and high sensitivity to stimulation. Nickel can accumulate in aquatic food chain magnification but its presence is not over.
Nickel for a range of species including mice, chickens, pigs, cows and essential. Deficiency include delays during pregnancy, infertility, anemia, acne, decreased hemoglobin and hematocrit and decrease the activity of several enzymes. Ni deficiency diseases have been identified in humans and is probably due to the fact that Ni in specific foods, used excessive demand, is essential.
Most of nickel salts, which enter the body through food, excreted. Nickel half-life of approximately 11 hours. Normal amount of nickel in the body, an average of about 3.7 grams per kilogram. The highest concentration of nickel in the bones, lungs, kidneys and liver can be seen (Merian 1992). Most toxic plants can be seen often in nickel, nickel carbonyl. Nickel concentrations in seawater 5 / 0-1 / 0 ng l. Are allergic to nickel toxicity, cancer and respiratory disorders seen.
EPA's maximum allowable concentration of nickel, 20 ng per kg per day and a maximum tolerable daily 2.1 mg in a 60 kg man has suggested.
Vanadium normal 015/0 percent of the Earth's crust. Limit of between 2.0 to 100 micrograms per liter of fresh water environments and marine environments between 2.0 to 29 micrograms per liter is estimated. Vanadium concentrations in coal and crude oil is in the range of up to 1000 kg. Estimates show that each year about 65 million tons of vanadium by natural factors (volcanoes, etc.) are released into the environment. Human activities (especially metal industry) every year over 200 tons of vanadium into the environment as well.
Vanadium is a natural resource and fossil fuel enters the environment in soil, water and air for longer stays. In aqueous solutions, sustainable and long-term adverse effects on aquatic organisms leaves.
The minimum permissible dose for Bzrgsaran, 3 / 0-1 / 0 mg per day is recommended. 100-15 mg per day may be toxic amounts of the symptoms such as anemia, inflammation and swelling of the eye, inflammation of the lungs, cataracts, memory loss, diarrhea, loss of appetite, and in the end is death. In most cases, vanadium causes biochemical changes in cells.
The reasons why the vanadium important to plants and animals and microorganisms exist. Of vanadium deficiency can lead to heart disease, elevated triglyceride levels, growth and bone destruction of tooth structure, reducing the stability and resistance against cancer and reduce the life noted.