ETC Environmental Monitoring & Instrumentation

Question 1

Which instrument is most commonly used by environmental technicians for real-time detection of volatile organic compounds (VOCs) in ambient air during field investigations?

Accepted Answer

Photoionization Detector (PID)

Answer

Gas Chromatograph/Mass Spectrometer (GC/MS)

Answer

Atomic Absorption Spectrometer (AAS)

Answer

Ion Chromatograph (IC)

Question 2

A four-gas monitor used in confined space entry typically measures which combination of parameters?

Accepted Answer

Oxygen, carbon monoxide, hydrogen sulfide, and combustibles (LEL)

Answer

pH, dissolved oxygen, conductivity, and turbidity

Answer

VOCs, hydrogen cyanide, chlorine, and ammonia

Answer

Radon, methane, carbon dioxide, and nitrogen oxides

Question 3

What does 'turbidity' measure in a water quality monitoring context, and what unit is it reported in?

Accepted Answer

The cloudiness caused by suspended particles, reported in Nephelometric Turbidity Units (NTU)

Answer

The acidity of water, reported in pH units

Answer

The concentration of dissolved solids, reported in mg/L

Answer

The light penetration depth, reported in meters

Question 4

When calibrating a dissolved oxygen (DO) meter using the air-saturated water method, what key parameter must the technician account for to ensure accuracy?

Accepted Answer

Both barometric pressure and salinity

Answer

pH of calibration water

Answer

Salinity and barometric pressure

Answer

Temperature and chloride concentration

Question 5

In groundwater monitoring, what is the purpose of purging a well before collecting a groundwater sample?

Accepted Answer

To remove stagnant water in the casing so the sample represents the aquifer

Answer

To clean the well screen of biological growth

Answer

To lower the water table before sampling

Answer

To aerate the groundwater to measure maximum DO potential

Question 6

What does specific conductance (or conductivity) measure in water, and what does a sudden spike in conductance at a monitoring well typically indicate?

Accepted Answer

The ability of water to conduct electricity; a spike may indicate inorganic contamination or saltwater intrusion

Answer

Dissolved oxygen; a spike indicates anaerobic conditions

Answer

Water temperature; a spike indicates thermal pollution

Answer

Turbidity; a spike indicates sediment loading