What analyses are required if groundwater is present in the excavation?

The requirement for analyzing groundwater present in an excavation revolves around understanding potential contaminants that may affect both human health and the environment. When groundwater is found, comprehensive testing is essential to accurately assess contamination.

The correct answer involves conducting BETX analyses, which target BTEX compounds (Benzene, Toluene, Ethylbenzene, and Xylenes). These are commonly associated with petroleum products and can indicate the presence of harmful substances that may leach into the groundwater. Testing sidewall soil samples for BETX compounds ensures a thorough evaluation of the surrounding environment, helping to identify if groundwater is impacted by contaminants from the excavation site.

This approach addresses both the water sample and the potential for contaminants in the soil surrounding the excavation, providing a holistic understanding of the contamination scenario. The rationale for requiring such analyses lies in the regulatory frameworks and best practices aimed at protecting both groundwater resources and public health.

The other options do not fully encompass the necessary analyses required when groundwater is present. Limiting to TPH analyses or PAH analyses ignores the specific risks posed by BTEX compounds in petroleum spills. Furthermore, physical assessments alone do not provide the chemical identification needed to determine the extent and nature of contamination.