Carcinogenicity and Toxicity – NCERT Class 11 Chemistry Notes
Introduction:
In Chemistry, it is not just about reactions and compounds, but also about their impact on living beings and the environment. The concepts of carcinogenicity and toxicity deal with the harmful effects of chemicals. Understanding these terms helps students stay aware of the safety and health risks associated with chemicals used in daily life. This topic is included in Chapter 14 – Environmental Chemistry of the Class 11 NCERT Chemistry textbook and is crucial for both academic knowledge and real-world awareness.
What is Toxicity?
Toxicity refers to the degree to which a substance can damage an organism. Toxic chemicals can affect the body in different ways depending on the dose, duration of exposure, route of exposure, and nature of the substance.
Examples of toxic substances:
• Carbon monoxide (CO) • Arsenic compounds • Mercury and its compounds • Pesticides like DDT
Types of Toxicity
Acute Toxicity: Results from a single or short-term exposure. Symptoms occur quickly. Example: Carbon monoxide inhalation. Chronic Toxicity: Results from prolonged or repeated exposure. Symptoms appear after months or years. Example: Arsenic-contaminated water.
What is Carcinogenicity?
Carcinogenicity refers to the ability of a substance to cause cancer. Carcinogens are substances that lead to uncontrolled cell growth and tumor formation.
Common Carcinogens
• Asbestos • Tobacco smoke • Formaldehyde • Aflatoxins • Industrial dyes and solvents
Classification of Carcinogens (IARC)
• Group 1 – Carcinogenic to humans • Group 2A – Probably carcinogenic • Group 2B – Possibly carcinogenic • Group 3 – Not classifiable
Impact on Health and Environment
Human Health: Organ damage, cancer, genetic mutations. Environment: Bioaccumulation, soil/water pollution.
Prevention and Safety Measures
• Use Personal Protective Equipment (PPE) • Proper chemical labeling and storage • Refer to Material Safety Data Sheets (MSDS) • Follow disposal protocols • Apply green chemistry principles
Summary Table
Conclusion:
Understanding carcinogenicity and toxicity is essential for every chemistry student. As future professionals, students must be aware of the potential hazards of chemicals and follow safety protocols to minimize risks.