CEI CEI Environmental Monitoring & Testing 1 — Questions and Answers
Question 1: What does a turbidimeter measure in water quality monitoring?
- Dissolved oxygen concentration
- Cloudiness caused by suspended particles (Correct answer)
- Chemical oxygen demand
- Total dissolved solids
Correct answer: Cloudiness caused by suspended particles
A turbidimeter measures turbidity, the optical clarity of water, by quantifying light scattered by suspended particulate matter.
Question 2: Which chain-of-custody requirement is most critical when collecting environmental samples for legal proceedings?
- Samples must be collected only in glass containers
- Sample custody must be documented and unbroken from collection to analysis (Correct answer)
- Samples must be analyzed within 24 hours of collection
- A state inspector must witness all sample collections
Correct answer: Sample custody must be documented and unbroken from collection to analysis
An unbroken, documented chain of custody ensures sample integrity and admissibility in legal or regulatory proceedings by tracking possession at every transfer.
Question 3: What does a passive air sampler measure compared to an active air sampler?
- It measures larger particles only
- It collects contaminants by diffusion without a pump over an extended period (Correct answer)
- It uses a pump to draw air through a sorbent at a fixed flow rate
- It measures only gaseous pollutants, not particulates
Correct answer: It collects contaminants by diffusion without a pump over an extended period
Passive air samplers collect airborne contaminants through diffusion alone — no pump required — allowing time-weighted average concentrations to be measured over days or weeks.
Question 4: In ambient air quality monitoring, what does the acronym 'NAAQS' stand for?
- National Ambient Air Quality Standards (Correct answer)
- Non-Attainment Area Quality Survey
- National Atmospheric Assessment and Quantification System
- Nationwide Air Assurance and Quality Specifications
Correct answer: National Ambient Air Quality Standards
NAAQS are EPA standards that set maximum allowable concentrations for six criteria pollutants in outdoor air to protect public health and welfare.
Question 5: Which sampling method involves collecting water from a stream at regular time intervals to create a representative composite sample?
- Grab sampling
- Time-integrated composite sampling (Correct answer)
- Low-flow purging
- Depth-discrete sampling
Correct answer: Time-integrated composite sampling
Time-integrated composite sampling combines sub-samples collected at fixed intervals, producing a sample that represents average water quality over the sampling period.
Question 6: What is the purpose of a field blank in environmental sampling quality control?
- To calibrate field instruments before sampling
- To detect contamination introduced during sample handling and transport (Correct answer)
- To verify laboratory analytical accuracy
- To establish background concentrations at a reference location
Correct answer: To detect contamination introduced during sample handling and transport
A field blank uses clean water or media that is opened, exposed to field conditions, and processed identically to samples to identify cross-contamination during collection or transit.
CEI CEI Environmental Monitoring & Testing 1
What does a turbidimeter measure in water quality monitoring?