Carcinogenicity an Toxicity of Certain Aromatic Hydrocarbons

Introduction

In this article, we will introduce the Carcinogenicity and toxicity of certain Aromatic Hydrocarbons from class 11 CBSE chemistry notes. In Carcinogenicity and toxicity of certain Aromatic Hydrocarbons, we will study.

Here we will discuss carcinogenicity, Carcinogenic Substances, toxicity, different Types of Toxicity, Classification of Toxicity, and aromatic hydrocarbons. Carcinogenicity and toxicity are important topics that fall in the syllabus.

Let’s begin with Carcinogenicity and toxicity.

What is meant by Carcinogenicity?

A carcinogen can be defined as the radiations, radionuclide, or the substance that are directly involved in the formation of cancer, these are called carcinogenic substances, and also a carcinogen, and the whole process is called carcinogenicity.

The carcinogenic substances can derange the cells that are involved in the metabolism process or damage the genome. Several radioactive substances are known as carcinogenic, but the carcinogenic behavior of these substances is led by the radiation they emit. Gamma rays and Alpha particles are some examples of carcinogenic substances. We also have non-radioactive carcinogens like inhaled asbestos, tobacco smoke, and certain dioxins.

Note: The smoke of Tobacco produces gasses that are harmful such as cancer-causing substances and carbon monoxide. Many times, carcinogenic substances are referred to as chemical carcinogens or synthetic chemicals, but they can be natural and synthetic in reality. Such substances may not be immediately toxic, as they are stealthy.

What are Carcinogenic Substances?

Cancer is a group of diseases that leads to abnormal cell growth in other parts of the body. In this disease, the body cells get harmed. It is seen often that carcinogenic substances raise the risk of cancer as they damage the metabolic cells of the body. Also, they damage the DNA component of the cell, which is directly associated with several biological processes of the body that lead to tumors.

The Aflatoxin B1 induced by a fungus grows on the surface of many nuts, grains, and peanut butter. It is a microbial carcinogenic substance as well that occurs naturally. The human papilloma and hepatitis B virus can lead to cancer in the person infected by them.

Other than fungus, radiation, and virus, several substances are carcinogenic. The substances like benzene and polynuclear hydrocarbons, which have two or more benzene rings fused, also have carcinogenic effects.

In case of incomplete combustion of materials that are organic such as petroleum, tobacco, and coal, the polynuclear hydrocarbons form. When the substances enter the human body they undergo biochemical reactions that lead to damaged DNA cells and cause cancer, further causing death.

Toxicity refers to the degree to which a chemical can harm the human cells of the body. We have seen the substances associated and the carcinogenicity effect. These substances are highly toxic, and should not be used to sustain a healthy body.

What is meant by Toxicity?

Toxicity refers to the degree to which a specific mixture of substances or a chemical substance can cause harm to an organism. It can refer to the complete effect on the organism, such as the effect on the substructure of the organism, such as a cell or an organ like the liver, bacterium, plant, or an animal. The word can also be used as an extension to describe the toxic effect on more complex groups such as society or family units metaphorically. The word is more or less used in place of poisoning in everyday life.

The whole concept of toxicology is described as the dose-dependent toxic effects; even water can be intoxicating if taken in abnormally high doses. And, Even a substance that is very toxic such as the venom of a snake, a certain small dose will have no detectable toxic effect.

What are the different types of Toxicity?

Toxic entities are of four types:

1. Radiation
2. Physical
3. Biological
4. Chemical

Classification of Toxicity

Here we take a look at the categorization of Toxicity.

The substances that have to be regulated and handled appropriately, must be labeled and classified properly. The classification is determined by approved testing or calculations. It determines the levels set by the government and scientists (tolerable daily intake levels, no-observed effect levels, and threshold limit values).

The pesticides are an example of a well-established toxicity class system and labels. Recently, most countries have several regulations that concern the number of tests, cut-off levels, and test types.

Aromatic Hydrocarbons

Aromatic hydrocarbons that contain more than one fused ring are known as polynuclear aromatic hydrocarbons or polycyclic aromatic compounds. The main source of polynuclear aromatic hydrocarbons is Coal tar. These hydrocarbons either possess an angular structure or linear structure. For example, pyrene, phenanthrene, anthracene, and naphthalene are hydrocarbons with linear structures. 

It is seen that the position and number of certain groups like methoxy, cyanide, hydroxide, and methyl in the compounds produce carcinogenic tendencies.

Due to incomplete combustion of tobacco, petroleum, coal, etc, such polynuclear aromatic hydrocarbons enter the environment. When these polynuclear aromatic hydrocarbons enter the body, these compounds go through several reactions and damage DNA. This leads to an immediate change in the structure of the DNA, causing cancer.

Eliminating the carcinogens from the surroundings can lessen the risk of cancer to a great degree. To achieve this, we have to start recycling the products of the combustion of petroleum and coal, controlling the use of tobacco, or using filters to lessen the breathing of the combustion of tobacco that is incomplete and keep a tab on the pollution caused by industries and automobiles.

Conclusion

A carcinogen can be defined as the radiations, radionuclide, or the substance that are directly involved in the production of cancer, these are called carcinogenic substances. Toxicity refers to the degree to which a specific mixture of substances or a chemical substance can cause damage to an organism. Aromatic hydrocarbons that contain two or more fused rings are known as polynuclear aromatic hydrocarbons or polycyclic aromatic compounds. The main source of PAHs is Coal tar. These hydrocarbons possess either an angular structure or linear structure. For example, pyrene, phenanthrene, anthracene, and naphthalene are hydrocarbons with linear structures.