What are the heavy metals, and what are the main heavy metals?

Metals with a density of more than 5 are collectively called heavy metals, such as gold, silver, copper, lead, zinc, nickel, cobalt, cadmium, chromium and mercury and other 45 kinds. In terms of environmental pollution, heavy metals mainly refer to heavy metals with significant biological toxicity such as mercury, cadmium, lead, chromium and arsenic, as well as general heavy metals with certain toxicity such as zinc, copper, cobalt, nickel, tin, etc. At present, mercury, cadmium, chromium, etc., which have attracted the most attention.

When heavy metals are discharged with wastewater, even in small concentrations, they can be hazardous. Environmental pollution caused by heavy metals is called heavy metal pollution. The characteristics of heavy metal pollution are manifested in the following aspects:

1) Some heavy metals in water bodies can be converted into more toxic metal compounds under the action of microorganisms, such as the methylation of mercury; 2) Heavy metals ingested by organisms from the environment can be enriched tens of millions of times in higher organisms through the biomagnification of the food chain, and then enter the human body through food, accumulate in some organs of the human body, cause chronic poisoning, and endanger human health;

Heavy metals refer to metals with a specific gravity greater than 4 or 5, and there are about 45 kinds, such as copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, molybdenum, gold, silver, etc. Although heavy metals such as manganese, copper, and zinc are trace elements needed for life activities, most of the heavy metals such as mercury, lead, cadmium, etc., are not necessary for life activities, and all heavy metals are toxic to the human body if they exceed a certain concentration.

For example, the clinical manifestations of mercury poisoning include headache, dizziness, fatigue, and fever. Oral and gastrointestinal symptoms include redness, swelling and soreness of the gums, erosion and bleeding, loose teeth, pus in the gingival socket, foul smell in the oral cavity, nausea, vomiting, loss of appetite, abdominal pain, and diarrhea. **Erythematous maculopapular rash may appear on contact, with more distribution on the extremities and head and face.

A small number of patients may have renal impairment, and a few severe patients may have acute interstitial pneumonia such as cough, chest pain, dyspnea, and cyanosis.

Heavy metal poisoning will cause the protein in the body to coagulate, you can see from the chemistry book of the third year of high school, if you are slightly poisoned, drink a lot of milk, the protein in the milk will react with heavy metals, so that it will not damage your own body functions, and seek medical attention immediately after drinking.

Heavy metals mainly include gold, silver, copper, iron, mercury, lead, cadmium, etc. Heavy metals accumulate in the human body to a certain extent, causing chronic poisoning.

In terms of environmental pollution, heavy metals mainly refer to heavy elements with significant biological toxicity such as mercury, cadmium, lead, chromium and arsenic.

Heavy metals are very difficult to biodegrade, but on the contrary, they can be enriched thousands of times by the biomagnification of the food chain and finally enter the human body. Heavy metals can interact strongly with proteins and enzymes in the human body, making them inactive, and may also accumulate in some organs of the human body, causing chronic poisoning.

Detection of heavy metals:

According to the fourth part of the Chinese Pharmacopoeia (2015 edition), there are three methods for the examination of heavy metals, namely: thioacetamide method, thioacetamide method after ignition, and sodium sulfide method.

The chromogenic agents used in the inspection are mainly thioacetamide and sodium sulfide test solutions. Hydrogen sulfide produced by hydrolysis of trace heavy metal ions (represented by Pb2+) and thioacetamide under acidic (pH is acetate buffer) conditions, or reaction with sodium sulfide under alkaline conditions to form a yellow to brownish-black sulfide suspension, and a colored suspension formed by reaction with a certain amount of standard lead solution under the same conditions, shall not be deeper.

The above content reference: Encyclopedia - Heavy Metals.

Copper, lead, zinc, tin, nickel, cobalt, antimony, mercury, cadmium, and bismuth.

Metals with a density above are called heavy metals. There are 60 natural metal elements with atomic numbers from 23 (v) to 92 (u), and except for 6 of them, the remaining 54 are more dense, so in the sense of density, these 54 metals are all heavy metals. However, when it comes to elemental classification, some of them are rare earth metals and some are classified as refractory metals.

In the end, 10 metal elements were actually classified as heavy metals in industry: copper, lead, zinc, tin, nickel, cobalt, antimony, mercury, cadmium and bismuth. These 10 kinds of heavy metals have no special commonalities except for the metal commonality and density greater, and each heavy metal has its own properties.

Whether it is air, soil, or even drinking water, it contains heavy metals, such as free radicals that cause aging, particles that are harmful to the skin, dust in the air, car exhaust, etc., and even tap water brings heavy metals to the skin, and even some heavy metal raw materials such as cadmium in some skin care products such as body lotion, are also one of them. The accumulation of heavy metals is quite harmful to the human body.

Toxic heavy metals are often considered highly toxic or damaging to the environment. Some are poisonous, while others are only toxic if they are overdosed on or encountered in certain forms. Inhaling certain metals, whether fine dust or the most common smoke, can also cause a condition known as metal fumimeism.

Hazards are most likely due to the widespread use of chromium, arsenic, cadmium, mercury, and lead, the toxicity of certain combinations or forms of elements, and their widespread distribution in the environment. For example, hexavalent chromium is as toxic as mercury vapor and many mercury compounds.

These five elements have a strong affinity for sulfur; In the human body, they usually bind, through the thiol group (-sh), to enzymes responsible for controlling the rate of metabolic reactions. The resulting sulfur metal bonds inhibit the normal function of the enzymes involved; Human health deteriorates and sometimes fatal. Chromium (hexavalent form) and arsenic are carcinogens; Cadmium causes degenerative bone disease; Mercury and lead can damage the central nervous system.

Metals with greater density than are called heavy metals. There are 60 natural metal elements with atomic number between 23 (v) 92 (u), and all but 6 are more than 54 densities. Therefore, these 54 metals are heavy metals in the sense of density.

But when it comes to classifying elements, some are rare earth metals, while others are classified as refractory metals. Finally, there are 10 metallic elements that are truly classified as heavy metals in industry: copper, lead, zinc, tin, nickel, cobalt, antimony, mercury, cadmium, and bismuth.

These 10 heavy metals have no special commonalities except for the metal commonality and greater density. Each heavy metal has its own properties.

Heavy metals are difficult to biodegrade. Instead, they can be enriched hundreds of times by biomagnification of the food chain and end up in the human body. Heavy metals can interact strongly with proteins and enzymes in the human body, rendering them inactive.

They can also accumulate in certain organs of the human body, causing chronic poisoning.

Copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, etc. Heavy metal elements refer to metal elements with a single mass density greater than 4500kg cubic meters under standard conditions, which are different from light metal elements (such as aluminum and magnesium).

Copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, etc. Heavy metal elements refer to metal elements with a single mass density greater than 4500kg cubic meters under standard conditions, which are different from light metal elements (such as aluminum and magnesium).

It mainly refers to toxic elements such as mercury, cadmium, lead, chromium and arsenic-like metals, which can be mined from mineral deposits, exposing minerals containing heavy metal elements from deep underground to the surface, or emitting them into soil, atmosphere or water through industrial processes. However, the degree of harm of pollution is very significant, and it is manifested in obvious toxic effects on living organisms. In addition, the different ions have different colors, in solution, copper ions are generally blue (the exception is green in concentrated copper chloride solution), ferrous ions are generally light green, and iron ions are generally yellow.

In the flame color reaction, copper is green and barium is yellow-green.

What does heavy metal meanThe original meaning of heavy metal refers to the metal with greater density, and there are originally 54 kinds of metals that are heavy metals, but when classifying the elements, some are classified as other metals. In the end, 10 metal elements were really classified as heavy metals in the industry, namely copper, lead, zinc, tin, nickel, cobalt, antimony, mercury, cadmium and bismuth.

When heavy metals accumulate in the human body to a certain extent, they can cause chronic poisoning. In the case of heavy metals in terms of environmental pollution, they mainly refer to heavy elements with significant biological toxicity such as mercury, cadmium, lead, chromium and arsenic.

Hazards of heavy metalsHeavy metals are very difficult to biodegrade, and can have strong interactions with proteins and enzymes in the human body, making them inactive, and may also accumulate in some organs of the human body, causing chronic poisoning. In addition, it is also very polluting to water resources.