A pollutant that is biodegradable is sewage.
Biodegradable means that a substance can be broken down into smaller, simpler compounds by natural processes, such as the action of microorganisms like bacteria or fungi. Sewage, which is a mixture of human and animal waste, is biodegradable because it contains organic matter that can be decomposed by microorganisms.
Crude oil and heavy metals are not biodegradable pollutants. Crude oil is a complex mixture of hydrocarbons that can persist in the environment for a long time and is difficult to break down naturally. Heavy metals, such as lead and mercury, are also persistent in the environment and can accumulate in living organisms, causing harm to ecosystems and human health.
Cellophane is a man-made material that is generally not biodegradable. It is made from cellulose, a natural polymer found in plant cell walls, but it is treated with chemicals to make it waterproof and resistant to degradation. Cellophane can persist in the environment for a long time, contributing to plastic pollution.