Environmental Monitoring & Instrumentation Flashcards
6 cards from real ETC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Environmental Monitoring & Instrumentation flashcards as text
Which instrument is most commonly used by environmental technicians for real-time detection of volatile organic compounds (VOCs) in ambient air during field investigations?
Answer: Photoionization Detector (PID)
The PID ionizes volatile organic compounds using ultraviolet light and measures the resulting ion current, providing fast, real-time total VOC readings in the field without laboratory analysis.
A four-gas monitor used in confined space entry typically measures which combination of parameters?
Answer: Oxygen, carbon monoxide, hydrogen sulfide, and combustibles (LEL)
Standard four-gas monitors simultaneously measure oxygen content, carbon monoxide, hydrogen sulfide, and lower explosive limit (LEL) for combustible gases to assess confined space safety.
What does 'turbidity' measure in a water quality monitoring context, and what unit is it reported in?
Answer: The cloudiness caused by suspended particles, reported in Nephelometric Turbidity Units (NTU)
Turbidity measures the optical clarity of water based on light scattering by suspended particles, and is reported in NTUs as measured by a nephelometer.
When calibrating a dissolved oxygen (DO) meter using the air-saturated water method, what key parameter must the technician account for to ensure accuracy?
Answer: Both barometric pressure and salinity
Dissolved oxygen solubility is affected by both barometric pressure (lower pressure = lower DO saturation) and salinity (higher salinity = lower DO solubility), so both must be entered for accurate calibration.
In groundwater monitoring, what is the purpose of purging a well before collecting a groundwater sample?
Answer: To remove stagnant water in the casing so the sample represents the aquifer
Well purging removes standing water from the casing that has been exposed to the atmosphere and may not be representative of actual aquifer water quality, ensuring the collected sample reflects true formation water.
What does specific conductance (or conductivity) measure in water, and what does a sudden spike in conductance at a monitoring well typically indicate?
Answer: The ability of water to conduct electricity; a spike may indicate inorganic contamination or saltwater intrusion
Specific conductance measures water's ability to conduct electrical current, which increases with dissolved ion concentration; a sudden spike can signal inorganic contamination, road salt influence, or saltwater intrusion.