DDT (Dichloro-Diphenyl-Trichloroethane) is a synthetic chemical compound that was widely used as an insecticide, particularly for mosquito control to combat malaria. It is a well-known example of a non-biodegradable pollutant.

Why is DDT non-biodegradable?
DDT is a chlorinated hydrocarbon, which means it has a stable chemical structure with carbon-chlorine bonds that are resistant to breakdown by natural biological processes (like bacteria or fungi). This leads to:

• Persistence: It remains in the environment for a long time (years or even decades).
• Bioaccumulation: It accumulates in the tissues of living organisms.
• Biomagnification: Its concentration increases at each successive trophic level in a food chain. For example, in a food chain: Water → Plankton → Small Fish → Large Fish → Birds. The top predators (like birds of prey) can accumulate dangerously high levels of DDT, leading to harmful effects such as eggshell thinning and population decline.

Why are the other options incorrect?

• Biodegradable pollutant: Substances like paper or food waste are biodegradable. DDT is not.
• A fertilizer: Fertilizers provide nutrients (like Nitrogen, Phosphorus) to plants. DDT is an insecticide, not a nutrient source.
• Greenhouse gas: Greenhouse gases (like CO${\mathrm{CO}}_2$, CH${\mathrm{CH}}_4$) trap heat in the atmosphere. DDT is not a gas; it is a solid compound and does not function as a greenhouse gas.

Final Answer: DDT is a non-biodegradable pollutant.

Related Topics & Formulae

Related Theory:

• Bioaccumulation Factor (BAF): It is a measure of how a substance accumulates in an organism compared to its concentration in the environment. $BAF=\frac{\text{Concentration in organism}}{\text{Concentration in environment}}$
• Biomagnification: The process where the concentration of a pollutant increases from one trophic level to the next.

Key Environmental Chemistry Concepts: Pollutants, their types (biodegradable vs. non-biodegradable), and their impact on ecosystems are crucial topics in environmental science.