Environmental Compliance Inspector Sampling, Monitoring, and Reporting 2 — Questions and Answers
Question 1: When collecting a composite wastewater sample over an 8-hour period, what is the primary advantage over a grab sample?
- It is less expensive to collect
- It averages out short-term concentration fluctuations (Correct answer)
- It requires no chain-of-custody documentation
- It does not require refrigeration
Correct answer: It averages out short-term concentration fluctuations
Composite samples blend multiple aliquots over time, smoothing out transient spikes and providing a more representative average concentration.
Question 2: An inspector notices a field blank submitted with groundwater samples shows measurable VOC contamination. What is the correct interpretation?
- The site groundwater is contaminated with VOCs
- The analytical lab has poor detection limits
- Sample contamination occurred during collection or transport (Correct answer)
- The purge water was not properly disposed of
Correct answer: Sample contamination occurred during collection or transport
A field blank that tests positive indicates that the sampling equipment, containers, or environment introduced contamination during the field process, not the site itself.
Question 3: Under 40 CFR Part 136, what is the maximum holding time for a dissolved oxygen (DO) grab sample before analysis?
- 24 hours
- 48 hours
- 15 minutes or analyze immediately (Correct answer)
- 7 days if refrigerated
Correct answer: 15 minutes or analyze immediately
Dissolved oxygen is extremely unstable and must be analyzed immediately in the field or within 15 minutes using approved methods.
Question 4: A facility's NPDES permit requires flow-proportional composite sampling. This means:
- Samples are collected at equal time intervals regardless of flow
- Aliquot volume is proportional to the flow rate at time of collection (Correct answer)
- Only peak flow events trigger sampling
- Samples are collected only during business hours
Correct answer: Aliquot volume is proportional to the flow rate at time of collection
Flow-proportional sampling adjusts each aliquot volume in proportion to the instantaneous flow rate, ensuring the composite reflects the true mass loading.
Question 5: Which QA/QC sample is used to assess potential cross-contamination between samples during field collection?
- Trip blank
- Equipment rinsate blank (Correct answer)
- Field duplicate
- Matrix spike
Correct answer: Equipment rinsate blank
An equipment rinsate blank is collected by rinsing cleaned sampling equipment with organic-free water, then submitting that rinse for analysis to detect residual contamination.
Question 6: When a Discharge Monitoring Report (DMR) must be submitted to EPA under NPDES, what happens if a facility fails to monitor a required parameter for a reporting period?
- The facility may leave the parameter blank with no consequence
- The facility must report a No Discharge for that period
- The facility must report a monitoring violation for that parameter (Correct answer)
- The facility may substitute a prior month's data
Correct answer: The facility must report a monitoring violation for that parameter
Failure to monitor a required NPDES parameter constitutes a monitoring violation that must be self-reported on the DMR, separate from any exceedance violation.
Question 7: An air quality inspector is reviewing PM2.5 continuous monitoring data and finds a 20% data capture rate for a quarterly reporting period. What is the regulatory implication?
- The data is valid because any data capture above 10% is acceptable
- The quarter is invalid because EPA requires at least 75% data capture for a valid quarter (Correct answer)
- The facility must submit a variance request within 90 days
- The monitoring equipment must be replaced immediately
Correct answer: The quarter is invalid because EPA requires at least 75% data capture for a valid quarter
EPA's NAAQS monitoring regulations require at least 75% data capture within a calendar quarter for the data to be considered valid for compliance determinations.
Environmental Compliance Inspector Sampling, Monitoring, and Reporting 2
When collecting a composite wastewater sample over an 8-hour period, what is the primary advantage over a grab sample?