Which of the following is NOT a biodegradable pollutant?

1. A

   Domestic waste

   (a) Domestic waste. It claims that household refuse breaks down naturally through biological processes, making it a biodegradable pollutant. Therefore, this option is incorrect as the question asks for a non-biodegradable pollutant.

2. B

   Urine

   (b) Urine. It asserts that excretory waste decomposes easily via microbial action in the environment, classifying it as a biodegradable substance. Hence, this option is incorrect.

3. C

   Faecal matter

   (c) Faecal matter. It states that organic excreta is naturally broken down by decomposers, which means it is a biodegradable pollutant. Consequently, this option is incorrect.

4. D

   Pesticide

   (d) Pesticide. It claims that synthetic agrochemicals and pesticides resist natural decomposition by microorganisms and persist in the environment for long periods, which makes them non-biodegradable pollutants. Official key is (d) because pesticides include persistent chemical compounds that do not break down easily through natural biological action, unlike domestic waste, urine, and faecal matter which are readily decomposed by natural agents.

Summary. Official key is (d) because pesticides are synthetic chemical substances that resist natural decomposition by microorganisms. Domestic waste, urine, and faecal matter are organic materials that readily break down through biological action in the environment. Therefore, they are classified as biodegradable pollutants. Pesticides accumulate in ecosystems and cause biomagnification, making them non-biodegradable. Thus, only option (d) correctly identifies the non-biodegradable pollutant among the given choices.