NPDES Chain-of-Custody Sampling Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a chain-of-custody form in
environmental sampling?
A. To analyze laboratory equipment
B. To document sample possession and handling
C. To calculate pollutant concentrations
D. To clean sampling instruments
Correct Answer: B. To document sample possession and handling
Rationale: Chain-of-custody forms provide a legal and procedural
record showing who handled the sample from collection to analysis.
2. Which action is MOST critical when initiating chain-of-custody?
A. Estimating sample cost
B. Labeling samples accurately at collection
C. Filtering samples in the field
, D. Adding preservatives later in the lab
Correct Answer: B. Labeling samples accurately at collection
Rationale: Proper labeling ensures traceability and prevents sample
misidentification.
3. Who is responsible for maintaining chain-of-custody integrity?
A. Laboratory only
B. Field sampler only
C. Every individual handling the sample
D. Regulatory agency only
Correct Answer: C. Every individual handling the sample
Rationale: All personnel handling the sample must ensure proper
documentation and secure transfer.
4. What information MUST be included on a chain-of-custody form?
A. Weather forecast
B. Sample identification and signatures
C. Equipment color
D. Employee salary
Correct Answer: B. Sample identification and signatures
Rationale: Identification and signatures confirm sample tracking and
accountability.
5. Which is a proper sample identification method?
A. Random numbering
, B. Personal initials only
C. Unique sample ID code
D. Lab technician nickname
Correct Answer: C. Unique sample ID code
Rationale: Unique IDs prevent confusion between samples.
6. What is the purpose of sample preservation?
A. Improve taste
B. Maintain sample integrity until analysis
C. Increase volume
D. Remove documentation needs
Correct Answer: B. Maintain sample integrity until analysis
Rationale: Preservation prevents chemical or biological changes
before testing.
7. What is the FIRST step when collecting a sample?
A. Transport to lab
B. Fill out lab report
C. Prepare sampling container and label
D. Dispose of equipment
Correct Answer: C. Prepare sampling container and label
Rationale: Proper preparation ensures traceability and prevents
contamination.
, 8. Which condition compromises chain-of-custody?
A. Sealed container
B. Missing signature during transfer
C. Proper labeling
D. Refrigerated storage
Correct Answer: B. Missing signature during transfer
Rationale: Missing signatures break custody documentation
integrity.
9. What does a custody seal indicate?
A. Sample is expired
B. Sample is contaminated
C. Sample has not been tampered with
D. Sample is unimportant
Correct Answer: C. Sample has not been tampered with
Rationale: Seals ensure sample security during transport and
storage.
10. Which temperature is commonly required for preserving water
samples?
A. 25°C
B. 10°C
C. 4°C
D. 0°C
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a chain-of-custody form in
environmental sampling?
A. To analyze laboratory equipment
B. To document sample possession and handling
C. To calculate pollutant concentrations
D. To clean sampling instruments
Correct Answer: B. To document sample possession and handling
Rationale: Chain-of-custody forms provide a legal and procedural
record showing who handled the sample from collection to analysis.
2. Which action is MOST critical when initiating chain-of-custody?
A. Estimating sample cost
B. Labeling samples accurately at collection
C. Filtering samples in the field
, D. Adding preservatives later in the lab
Correct Answer: B. Labeling samples accurately at collection
Rationale: Proper labeling ensures traceability and prevents sample
misidentification.
3. Who is responsible for maintaining chain-of-custody integrity?
A. Laboratory only
B. Field sampler only
C. Every individual handling the sample
D. Regulatory agency only
Correct Answer: C. Every individual handling the sample
Rationale: All personnel handling the sample must ensure proper
documentation and secure transfer.
4. What information MUST be included on a chain-of-custody form?
A. Weather forecast
B. Sample identification and signatures
C. Equipment color
D. Employee salary
Correct Answer: B. Sample identification and signatures
Rationale: Identification and signatures confirm sample tracking and
accountability.
5. Which is a proper sample identification method?
A. Random numbering
, B. Personal initials only
C. Unique sample ID code
D. Lab technician nickname
Correct Answer: C. Unique sample ID code
Rationale: Unique IDs prevent confusion between samples.
6. What is the purpose of sample preservation?
A. Improve taste
B. Maintain sample integrity until analysis
C. Increase volume
D. Remove documentation needs
Correct Answer: B. Maintain sample integrity until analysis
Rationale: Preservation prevents chemical or biological changes
before testing.
7. What is the FIRST step when collecting a sample?
A. Transport to lab
B. Fill out lab report
C. Prepare sampling container and label
D. Dispose of equipment
Correct Answer: C. Prepare sampling container and label
Rationale: Proper preparation ensures traceability and prevents
contamination.
, 8. Which condition compromises chain-of-custody?
A. Sealed container
B. Missing signature during transfer
C. Proper labeling
D. Refrigerated storage
Correct Answer: B. Missing signature during transfer
Rationale: Missing signatures break custody documentation
integrity.
9. What does a custody seal indicate?
A. Sample is expired
B. Sample is contaminated
C. Sample has not been tampered with
D. Sample is unimportant
Correct Answer: C. Sample has not been tampered with
Rationale: Seals ensure sample security during transport and
storage.
10. Which temperature is commonly required for preserving water
samples?
A. 25°C
B. 10°C
C. 4°C
D. 0°C
