CEI CEI Environmental Monitoring & Testing 2 — Questions and Answers
Question 1: What does a photoionization detector (PID) measure during field investigations?
- Particulate matter concentrations
- Volatile organic compounds by ionizing them with UV light (Correct answer)
- Radiation levels from radioactive contamination
- Dissolved heavy metals in groundwater
Correct answer: Volatile organic compounds by ionizing them with UV light
A PID uses ultraviolet light to ionize VOC molecules, generating a measurable current proportional to the total VOC concentration in air.
Question 2: What is the minimum number of groundwater monitoring wells typically required at a RCRA-regulated facility to assess upgradient and downgradient conditions?
- One upgradient, one downgradient
- One upgradient, three downgradient (Correct answer)
- Two upgradient, two downgradient
- Three upgradient, one downgradient
Correct answer: One upgradient, three downgradient
RCRA regulations typically require at least one upgradient (background) well and three downgradient wells to detect statistically significant contamination from a regulated unit.
Question 3: Which parameter is most useful for characterizing the biological health of a surface water body in environmental monitoring?
- Total dissolved solids (TDS)
- Benthic macroinvertebrate assemblage (Correct answer)
- Conductivity
- Water temperature
Correct answer: Benthic macroinvertebrate assemblage
Benthic macroinvertebrate communities are sensitive bioindicators that integrate pollution effects over time and are widely used to assess stream biological integrity.
Question 4: What does a 'trip blank' detect in volatile organic compound (VOC) sampling?
- Cross-contamination from sample collection equipment
- Contamination introduced during laboratory preparation (Correct answer)
- VOC background levels at the sampling location
- VOC concentrations in the shipping carrier's vehicle
Correct answer: Contamination introduced during laboratory preparation
A trip blank is a clean water sample prepared in the lab and carried unopened throughout the sampling trip to detect cross-contamination from VOC vapors during transport.
Question 5: Which monitoring approach uses satellite or aerial imagery to detect changes in land surface conditions related to environmental contamination?
- Remote sensing (Correct answer)
- Geophysical survey
- Passive diffusion sampling
- Isotope ratio analysis
Correct answer: Remote sensing
Remote sensing uses electromagnetic radiation data from aerial or satellite platforms to identify vegetation stress, thermal anomalies, or surface changes indicative of contamination.
Question 6: What is the purpose of 'well development' after installing a monitoring well?
- To seal the annular space to prevent surface water infiltration
- To remove drilling fluids and fine particles so the well produces formation water (Correct answer)
- To collect the first baseline groundwater sample
- To measure the static water level in the aquifer
Correct answer: To remove drilling fluids and fine particles so the well produces formation water
Well development removes drilling fluids, grout intrusions, and fine sediments from the filter pack and formation so subsequent samples accurately represent aquifer conditions.
CEI CEI Environmental Monitoring & Testing 2
What does a photoionization detector (PID) measure during field investigations?