Which process involves the breakdown of chemicals without biological organisms?

The process that involves the breakdown of chemicals without the involvement of biological organisms is chemical degradation. This refers to the transformation of chemicals into simpler substances through chemical reactions, often triggered by environmental factors such as heat, light, or the presence of other chemicals. In this context, chemical degradation can include reactions like hydrolysis, oxidation, or reduction, which can occur in the environment but do not involve living organisms.

In contrast, microbial action involves the degradation of substances by microorganisms, including bacteria and fungi, which actively consume and break down organic material. Photodegradation relies on light energy, typically ultraviolet light, to initiate breakdown processes, while phytodegradation refers to the absorption and breakdown of pollutants by plant roots. These processes all involve biological or environmental elements that differentiate them from pure chemical degradation.