Concept and option-wise explanation

In the question, oyster mushrooms (a fungus) are added to diesel‑contaminated soil and successfully degrade polycyclic aromatic hydrocarbons (PAHs). Using fungi to detoxify pollutants is specifically termed mycoremediation, so option (3) is correct.

(1) Phytoremediation

• Phytoremediation uses plants and their associated microbes to absorb, transform, stabilize, or volatilize contaminants.

• Because the key agents here are mushrooms (fungi), not plants, this term does not apply.

(2) Chemoremediation

• Chemoremediation (or chemical remediation) refers to using chemical agents such as oxidants or reducing agents to destroy or immobilize pollutants.

• In the scenario, no chemicals are added; only biological fungal activity is involved.

(3) Mycoremediation – correct

• Mycoremediation is bioremediation using fungi, especially their mycelium and extracellular enzymes, to degrade complex pollutants like PAHs, petroleum hydrocarbons, dyes, and pesticides.

• Oyster mushrooms (Pleurotus species) produce strong ligninolytic enzymes (laccases, peroxidases) that can break down the aromatic ring structures of PAHs, turning them into less toxic compounds.

• Therefore, this fungal clean‑up of diesel‑contaminated soil is classic mycoremediation.

(4) Zooremediation

• Zooremediation would involve animals (e.g., worms, insects, fish) in pollutant removal or transformation.

• Since animals are not used in this example, this term is not appropriate.

Thus, the process described is accurately called mycoremediation (option 3).