Which process refers to the breakdown of a pesticide due to exposure to sunlight?

• A. Bioconcentration
• B. Leaching
• C. Photodecomposition
• D. Volatilization

Answer: (C)

Photodecomposition is the breakdown of a pesticide caused by exposure to light, especially sunlight. When pesticide molecules absorb photons, the energy can break chemical bonds and transform the molecule into different, often less active, products. This sunlight-driven degradation helps reduce how long the pesticide remains on plant surfaces or in shallow water, affecting its environmental persistence. Bioconcentration involves accumulation in organisms, not breakdown by light. Leaching is the movement of substances downward through soil with water, not their chemical decomposition. Volatilization is the substance changing to a gas and leaving as vapor, which is a phase change rather than chemical breakdown.