CES Environmental Sampling & Data Analysis 3

Question 1

Which data quality indicator (DQI) specifically addresses whether the sampling locations and design are sufficient to represent the study area?

Accepted Answer

Representativeness

Answer

Representativeness reflects how well sample results characterize the true conditions of the population or area being studied.

Question 2

When using a GPS unit to document sampling locations in a wetland delineation, which coordinate system is most commonly specified in USACE jurisdictional determinations?

Accepted Answer

WGS84 decimal degrees latitude/longitude

Answer

The USACE and most federal environmental agencies record sample locations as WGS84 decimal degrees latitude/longitude for compatibility with standard GIS and GPS systems.

Question 3

A soil sample collected for PAH analysis must be stored at 4°C and analyzed within 14 days. What holding time violation occurs if the sample is analyzed on day 15?

Accepted Answer

Holding time exceedance

Answer

Analyzing a sample after its specified holding time is a holding time exceedance, which may render the data unusable or require qualification.

Question 4

In a systematic grid sampling design, what is the primary advantage over simple random sampling for soil contamination assessment?

Accepted Answer

It ensures spatial coverage and reduces the risk of missing contaminated areas

Answer

Systematic grid sampling provides uniform spatial coverage across the study area, reducing the chance of missing isolated contamination hotspots.

Question 5

What is the function of an internal standard in GC/MS analysis of environmental samples?

Accepted Answer

To calibrate detector response and correct for instrument variability between injections

Answer

Internal standards are compounds added at a known concentration before injection to correct for instrument response variability and injection volume differences.

(CES) Certified Environmental Scientist Practice Test

(CES) Certified Environmental Scientist Practice Test

CES Environmental Sampling & Data Analysis 3