Which of the following is an example of a bulk sample?

A bulk sample refers to a sample that is collected from a homogeneous material in a specific location and is typically analyzed to determine the composition or presence of hazardous substances. The correct answer, which is spray insulation sampled for asbestos, exemplifies a bulk sample since it involves taking a portion of the insulation material itself for analysis. This type of sampling is essential in situations where a solid material is suspected of containing a hazardous substance, such as asbestos, which is relevant in occupational hygiene to ensure safe working environments.

The collection of spray insulation allows for a direct analysis of the material in question. This helps in assessing potential exposure risks and determining necessary remediation actions if hazardous materials are present.

In contrast, the other options represent different types of samples. Water from a drinking fountain is a liquid sample, which could be analyzed for contaminants but does not fall under the category of bulk sampling. Dust from a workbench is typically collected as a surface sample rather than bulk, as it may not represent a homogeneous material layer. An air filter from an HVAC system is designed to capture airborne particulate matter, and it serves as an air sample, focused on airborne exposure rather than a bulk material analysis.

Understanding the characteristics of bulk samples is crucial for effective assessment and management of occupational health risks.