Carbon monoxide, toxic effects

Mankind encountered the effects of carbon monoxide as far back as prehistoric times. It is the most common poison with a suffocation action. It is second to carbon dioxide with respect to the amounts of industrial emissions. Carbon monoxide toxicity is due to its affinity to haemoglobin. This affinity is higher by a factor of 200 than that of oxygen. Haemoglobin... 

The second hazard is toxicity. The toxic materials may have direct effects. An example is pulmonary paralysis from hydrogen sulfide. Toxic materials can be asphyxiants that intermpt oxygen transport. An example is carbon monoxide. Toxic materials may be irritants at very low concentrations and lethal at higher levels, such as eye irritants that reduce vision. 

Carbon monoxide toxicity. It is well known that CO can induce negative symptoms in humans. These effects start to occur at levels above 70 ppm. At these levels, the concentration of CO-Hb in the blood can reach 10-15%. When the CO-Hb concentration is much higher than this, more severe symptoms are observed. 

The long-term effects of CECs and HCECs leaking into the environment have been discussed. Combustion where aU ceUular plastics can evolve smoke containing carbon monoxide and in certain cases cyanide and other toxic gases from various constituents involved in thein manufacture is also a consideration. 

Levels below 19.5% oxygen can have detrimental effects if the body is already under stress, e.g. at high altitudes. Exposures below 18% should not be permitted under any circumstance. Other chemicals, e.g. carbon monoxide, result in toxic anoxia due to damage of the body s oxygen transport or utilization mechanism. 

In degreasing operations, there may be exposures to carbon monoxide, which may compound symptoms reported by workers (NIOSH 1973). Illnesses of certain employees, documented at a neighboring hospital, included headache, nausea, dizziness, and chest pain. The NIOSH report concluded that the first employee illness reports were due to toxic effects of carbon monoxide complicated by trichloroethylene exposure. The... 

In spite of the complexity of dealing with atmospheres containing multiple toxicants, considerable progress has been made in understanding some of the effects from studies using rodents. For example, it is fairly well agreed that carbon monoxide and hydrogen cyanide appear to be additive when expressed as fractional doses required to cause an effect (21,22). Thus, as a reasonable approximation, the fraction of an effective dose of CO can be added to that of HCN and the time at which the sum becomes unity (100%) can be used to estimate the presence of a hazardous condition. 

An enzyme is a protein that speeds up a biochemical reaction without itself experiencing any overall change. In chemical language, such a compound is called a catalyst and is said to catalyze a reaction. Chemists employ a variety of compounds as laboratory catalysts, and many industrial chemical processes would be impracticably slow without catalysis. An automobile s catalytic converter makes use of a metal catalyst to accelerate conversion of toxic carbon monoxide in the exhaust to carbon dioxide. Similarly, our bodies biochemical machinery effects thousands of different reactions that would not proceed without enzymatic catalysis. Some enzymes are exquisitely specific, catalyzing only one particular reaction of a single compound. Many others have much less exacting requirements and consequently exhibit broader effects. Specific or nonspecific, enzymes can make reactions go many millions of times faster than they would without catalysis. 

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