Harmful effects of chromium and mercury on human health

Toxic effects of chromium:

Primarily chromium compounds are present in two states trivalent state. It is also called a biological state which is not toxic and the second one is the hexavalent state which is toxic and evacuated by the industrial waste.

The oxidation state is the major factor that governs the toxicity of the chromium compounds. Chromium VI is a much more corrosive irritating and oxidizing compound systematically than the chromium III compounds concerning similar amounts and solubilities.

The biological interaction of chromium is uncertain. This uncertainty of toxicity helps determine the effects.

Mechanism of toxication of chromium:

The chromium III compound is less oxidant and poorly absorbed. It is attributed to Cr VI for all toxicological effects. It can enter the body of an organism by different routes like pass through the lungs gastrointestinal tracks or by direct intact of the skin.

The chromium VI can enter in the body by different kinds of the cell under different physiological effects. The reduction of chromium VI must be done to reduce the toxic effects which impart different disorders.

For the sake to reduce the Cr VI compound different chemicals are helpful and produce as a cell product. These chemicals include glutathione (GSH) reductases, hydrogen peroxide (H2O2) ascorbic acid.

The Cr VI reduction is referred to as the detoxification process when it is far from the target site. If the chromium VI compound is reduced to chromium III compound before reaching the target tissues or cell. It is called the reduction of the chromium which is nontoxic. 

Harmful effects of Chromium on health:

In the field of health, toxicology has done a vital role. Every compound has a specific role in the body so many doses can cause harmful effects. So an adequate amount of a substance is requiring for the proper functioning of the body.

The different stages of the chromium can cause different health problems for instance the Cr IV is harmful to the human health of those people who are living or working in the steel and textile industry. Tobaccos smokers also have exposure to chromium. The Cr IV can cause the following health problems

  • Skin rashes
  • Respiratory disorders
  • Weakened immune system
  • Upset stomach and ulcer
  • Kidney and liver damage
  • Alternation of genetic material
  • Lung cancer

Respiratory effects:

The toxic Cr III and Cr IV also harm the respiratory system. Whenever the exposure of chromium takes place to the respiratory system it causes a hazardous effect.

Chromium adverse effects on health can be determined by the exposure of chromium doze on the body.


Asthma is the condition in which shortness of breath, pain in the chest, and tightness in the chest take place by the exposure of irritants of different kinds like chemicals like fumes of heavy metals gases and dust.

Chronic pharyngitis:

It is the sort of throat caused by inflammation which is further caused by the irritants of heavy metals bacterial and viral attack.

Chronic Rhinitis:

It is the inflammation of the inner lining of the nose. It may be caused by smoking, irritants in the air, and harmful medications for a long time.

 Polyps of Upper Respiratory Tract:

Polyps of the upper respiratory tract are the lesions the produce in the nose throat or windpipe through the irritants in the air.

Ulceration of Respiratory track:

These are the wounds in the respiratory tract caused by the poison effect of chromium and other heavy metals.

Toxic Effect of Mercury:

The term toxic metal is defined as the metal with a heavy density and low dose that causes a serious effect on the health such as Cr, Cd, Pb, Zn, and Hg. He is the naturally occurring metal present in all environments air water and soil.

The people who are working in the industries have a heavy to become exposure to this hazardous metal. Both direct and intermediate exposure has been experienced. Industrialist put their wastage in the soil of the lake which is directly or indirectly attached to the rivers or seas.

These heavy metals are exposed to the organisms present in the water which forms intermediate. World Health Organization WHO has considered mercury as one of the ten chemicals or group of chemicals which has concerned to the public health.

Mercury is exposed in two forms methyl mercury and ethyl mercury both are organic but methyl mercury is the most harmful and causes a hazardous effect on health.

On the other hand, ethyl mercury is used in the process of preservation of various dozes and vaccines and cannot pose any health risks. The main or the expected source of methyl mercury is the fish affected by the mercury.

Forms of mercury:

It is present in three forms

  • Elemental mercury also called metallic mercury
  • Monovalent mercury also called mercurous mercury Hg2 2+
  • Divalent mercury also called mercuric mercury Hg2+

Effect of mercury on Health:

Mercury causes adverse effects considerably on all parts of the body here we describe the harmful effect on the nervous system and cardiovascular system.

The nervous system is an important part of the body that coordinates all body parts and controls them. The nervous system is very critical. On the nervous system, the harmful effect of mercury takes place in different ways such as irritability excitability, and paraesthesia in low-level exposure, and high-level exposure causes high muscle spam and even death.

There are different mechanisms for the exposure of mercury to the nervous system. Both inorganic and organic mercury affects the nervous system. Methyl mercury directly attacks or reacts with the receptors in the nervous system like acetylcholine receptors on the peripheral nervous system.

Mechanism of ROS:

Most of the injuries on the nervous system which are caused by methyl mercury are due to its increase in ROS. The experiments have been done on the bovine cells which are first exposed to methyl mercury which causes an increase in the ROS and then exposed to the anti-oxidant PQQ pyrroloquinoline Quinone which attenuated the cytotoxicity effect of methyl mercury. This strengthened the idea to neutralized methyl mercury-induced toxicity.

Methyl mercury has also the ability to reduce the number of neurons with parental exposure to methyl mercury.it has a high affinity to bind with the sulfhydryl group. In CNS development the organization of microtubule is very important methyl mercury inhibits this organization by attaching the sulpha hydrate group with tubulin and the CNS is not developed properly.

Effect on the cardiovascular system:

Mercury not only affects the nervous system but also affects the cardiovascular system mainly caused by inorganic mercury and methyl mercury.

Mercury exposure causes following cardiovascular disorders. Such as hypertension myocardial infarction coronary dysfunction and atherosclerosis. Atherosclerosis is caused by oxidized low-density lipoprotein (LDL).

An enzyme paraoxonase decreases LDL which is an important antioxidant for atherosclerosis is inactive by exposure to mercury.

Mercury exposure also causes the failure of the left ventricular systolic pressure which causes atrioventricular conduction delay. The exam mechanism behind this disorder is not understood.

Although experiments on mice have taken place the intravenous injection of Hgcl2 5mg/1kg has been injected to rats and its cardiac diastole is a failure with pulmonary hypertension. Hgcl2 increases the blood pressure and increases the vascular activities of phenylephrine which increases the generation of free radicals.

Reviewed by:
Dr. Muhammad Adnan Asghar (Ph.D.)
Chinese Academy of Sciences Fuzhou, Fujian