ETC Cheat Sheet 2026

The 30 highest-yield ETC facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Eutrophication of a lake or reservoir is primarily caused by excess loading of which two nutrients from agricultural and urban runoff? → Nitrogen and phosphorus
2. What is the primary purpose of a Continuous Emissions Monitoring System (CEMS)? → To provide real-time measurement of pollutant emissions from a stationary source
3. In soil vapor extraction (SVE), which contaminant property most directly governs how effectively the technology will remove the target compound? → Henry's Law constant (volatility)
4. In a pump-and-treat system, what phenomenon describes the rebound of contaminant concentrations in extracted groundwater after pumping is reduced or stopped? → Concentration rebound
5. What test is used to determine if a solid waste exhibits the toxicity characteristic under RCRA? → Toxicity Characteristic Leaching Procedure (TCLP)
6. What does the term 'plume diving' describe in a groundwater contamination scenario? → Contaminant sinking into deeper aquifer units due to density or recharge
7. What unit of measurement is used for the 24-hour NAAQS standard for PM2.5? → Micrograms per cubic meter (µg/m³)
8. What is the primary treatment objective of coagulation and flocculation in a drinking water treatment plant? → To aggregate suspended particles and colloids into larger settleable masses
9. Which parameter is commonly measured in water quality testing? → pH level
10. When recording field measurements for groundwater depth using an electronic water level meter (e-tape), measurements are typically reported as: → Depth to water from the top of the well casing to the nearest 0.01 foot
11. What is the most appropriate container material for collecting volatile organic compound (VOC) samples? → Glass container
12. Which of the following wastes is explicitly excluded from RCRA hazardous waste regulation? → Household hazardous waste
13. What is a benefit of implementing a pollution prevention plan in a facility? → Reduces waste and improves efficiency
14. Which U.S. federal law serves as the primary legislation for regulating water pollution? → Clean Water Act (CWA)
15. Which regulation governs the discharge of pollutants into U.S. waters? → Clean Water Act
16. What is the primary purpose of a hazardous waste contingency plan at a generator facility? → To document emergency response procedures for accidents involving hazardous waste
17. Which of the following is considered a primary strategy in pollution prevention programs? → Source reduction
18. What does the term 'water hammer' describe in a drinking water distribution system, and what hazard does it present? → A pressure surge caused by rapid flow velocity changes that can damage pipes and joints
19. What does a chain of custody form ensure in sample analysis? → Tracks who handled the sample
20. What is the main purpose of using scrubbers in industrial facilities? → To remove pollutants from industrial emissions
21. What is 'opacity' as used in air emissions monitoring? → The percentage of light obscured by emissions leaving a stack or fugitive source
22. Which type of air pollution control device uses an electrical charge to remove particulate matter from industrial exhaust gas streams? → Electrostatic precipitator (ESP)
23. Which EPA-approved method is used to collect volatile organic compound (VOC) air samples for subsequent laboratory analysis? → SUMMA canister or Tedlar bag with EPA TO-15
24. What is the main purpose of the National Environmental Policy Act (NEPA)? → To mandate environmental reviews for federal projects
25. What does the acronym NAAQS stand for? → National Ambient Air Quality Standards
26. A field technician uses a combustible gas indicator (CGI) and observes a reading of 10% LEL in a utility vault. What action should be taken? → Ventilate the space and continue monitoring before entry
27. Which EPA characteristic makes a waste hazardous due to its ability to catch fire under standard conditions? → Ignitability
28. What is the primary mechanism by which activated carbon (GAC) removes contaminants from drinking water or groundwater treatment systems? → Physical adsorption of organic molecules and some inorganics onto the carbon surface
29. Which of the following is the primary reason for using chain of custody documentation in environmental sampling? → To ensure sample integrity and legal defensibility
30. Which water quality parameter, measured in mg/L as CaCO3, indicates the water's ability to resist changes in pH? → Alkalinity