Which of the following is an example of an organic contaminant?

An organic contaminant refers to substances that are derived from living organisms or are related to organic chemistry. In this context, grease is considered an organic contaminant because it is typically composed of fats, oils, and other carbon-based compounds that can be derived from animal or plant sources. Such contaminants can be challenging to remove from surfaces when preparing for painting, as they can interfere with the adhesion of the paint and ultimately affect the finish and durability of the coating.

In contrast, dust and soil are predominantly inorganic materials and do not consist primarily of carbon-containing compounds. Rust is the result of the oxidation of metal, which is also an inorganic matter. Understanding the nature of these contaminants is crucial for ensuring proper surface preparation in paint application processes, as it allows for the selection of appropriate cleaning methods to achieve optimal adhesion and finish quality.