California UST System Operator Practice Test

The collection of soil gas samples for laboratory analysis is an effective method for soil vapor monitoring because it allows for the precise identification and quantification of volatile organic compounds (VOCs) and other harmful substances present in the soil vapor. This method provides reliable data regarding the concentrations of these contaminants, enabling operators to assess the potential risks to human health and the environment.

Laboratory analysis can differentiate between various types of compounds and determine their concentrations, giving a comprehensive overview of the contamination levels. By comparing the results against environmental regulations and health standards, operators can make informed decisions regarding remediation and mitigation efforts.

The other methods mentioned, while they might support monitoring efforts, do not provide the same level of detail or reliability. Gas detectors generally measure concentrations in real-time but may not offer the extensive sampling and analysis needed for accurate assessment. Moisture sensors typically monitor water content rather than soil vapors, and visual inspection does not provide quantitative data on soil vapor contamination. Therefore, collecting soil gas samples for laboratory analysis stands out as the best approach for thorough soil vapor monitoring.