People working in manufacturing and chemical industries are more prone to health hazards as they are exposed to dangerous substances that have adverse health effects on them. Frequent exposure to synthetic substances causes nausea, vomiting, and headaches, which, if not treated at earlier stages turn into life threatening diseases. These substances directly or indirectly exert toxic elements through biological, chemical, physical, genetic or psychological agents on living organisms and other biological systems, and this study is known as toxicology. In an organism these toxic elements are absorbed systematically through the skin, lungs, or gastro-intestinal tracts. The effect of these toxics once absorbed in the body depends on the concentration of the target organs, and the immunity system of the organism.
For a chemical or a substance to absorb, dispense, cut down and later get excreted, the toxicant must pass through many cell membranes. Most of the toxicants pass the cell membranes either through active diffusion, or passive diffusion. The toxicant such as lead is known to be absorbable from the intestine by active transport systems . The intestine consists of special carrier-mediated transport systems, which are in charge to absorb the nutrients, for example, amino acids, calcium, iron and sodium. Active transport is usually associated with accumulating high concentrations of molecules that the cell needs, such as ions, glucose and amino acids. Active Transport Systems consists of primary active transport and secondary active transport. Using chemical energy, from adenosine triphosphate (ATP) is primary active transport, and using electrochemical gradient is secondary active transport.
Once a substance enters a body, it distributes rapidly, and the rate of distribution depends on the speed and blood quantity flowing in that organ. Binding process also takes place for a substance to get distributed and absorbed in an organ. Covalent binding is irreversible, and Non-covalent binding is reversible. Substance binding can increase its concentration in an organ rapidly, for example. 30 minutes after a single administration of lead, its concentration in the liver is 50 times higher than that in the plasma . On completion of the absorption, and distribution process the toxics are excreted out either at a rapid rate or slowly in the form of urinary excretion, biliary excretion, lungs or by gastrointestinal tract.
After the process of absorption, distribution and excretion, many chemicals are known to undergo biotransformation that occurs in the organs and tissues, and most important of the organs being the liver, lungs, intestine, skin, stomach and kidneys . The conversion of the parent compounds into metabolites and later to conjugates, involving any of these reactions is known as biotransformation. It is known that the blood level rises when a toxicant is absorbed in the body, and result in the rate of excretion, biotransformation, and distribution increase to other organs and tissues. The rate and the type of biotransformation of a toxicant differs between species of an animal to a different species and even from one strain to another, which results in the difference of toxicity in between these species.
Health hazards from the synthetic substances can be prevented only by avoiding them in the surrounding atmosphere. Some chemicals consist of mild, reversible effects, but different chemicals may contain very toxic content. Methyl, and Mercury are considered exceptions because they are also available in variety of fishes . There will be a never ending requirement for toxic substances, and these substances may have positive or negative impacts on the people. The clearance of the substances and their byproducts having negative impact on the organisms is anticipated to produce no environmental hazards, unpleasantly affecting individuals and the environment.
References
Kacew, S., & Lee, B.-M. (2012). Lu's Basic Toxicology - Fundamentals, Target Organs,and Risk Assessment (6th ed.). CRC Press.
