HIC Water Quality & Sampling 3 — Questions and Answers
Question 1: A drinking water sample tests positive for E. coli. What is the required public notification timeline for this acute MCL violation?
- Within 24 hours (Correct answer)
- Within 30 days
- Within 1 year
- Within 72 hours
Correct answer: Within 24 hours
E. coli presence is an acute MCL violation requiring Tier 1 public notification within 24 hours using television, radio, or direct contact.
Question 2: Which parameter is used as the primary indicator of fecal contamination in a rapid water quality field test?
- pH level
- Fecal coliform or E. coli (Correct answer)
- Dissolved oxygen
- Hardness
Correct answer: Fecal coliform or E. coli
Fecal coliform and E. coli are indicators of fecal contamination because they are consistently present in the intestinal tracts of warm-blooded animals.
Question 3: When collecting a water sample for nitrate analysis near agricultural land, which container and preservation method is correct?
- Plastic bottle, no preservation needed, analyze within 48 hours or refrigerate at 4°C (Correct answer)
- Glass bottle with sulfuric acid, analyze within 6 hours
- Plastic bottle with sodium thiosulfate, analyze within 24 hours
- Glass amber bottle, freeze immediately
Correct answer: Plastic bottle, no preservation needed, analyze within 48 hours or refrigerate at 4°C
Nitrate samples are collected in plastic bottles with no preservative and held at 4°C; they must be analyzed within 48 hours.
Question 4: Under the Safe Drinking Water Act, which federal agency sets and enforces drinking water standards for public water systems?
- CDC
- USDA
- EPA (Correct answer)
- OSHA
Correct answer: EPA
The EPA establishes National Primary and Secondary Drinking Water Regulations under the Safe Drinking Water Act.
Question 5: A health inspector evaluates a well serving a food establishment. Which setback distance from a septic system is generally required for a new well under typical state guidelines?
- 10 feet
- 25 feet
- 50 feet
- 100 feet (Correct answer)
Correct answer: 100 feet
Most state regulations require a minimum 100-foot setback between a private well and a septic tank or drain field to prevent contamination.
Question 6: Which waterborne pathogen is responsible for the largest documented U.S. drinking water outbreak and is resistant to standard chlorination at typical doses?
- Giardia lamblia
- Cryptosporidium parvum (Correct answer)
- Legionella pneumophila
- Hepatitis A virus
Correct answer: Cryptosporidium parvum
The 1993 Milwaukee outbreak of Cryptosporidium parvum affected over 400,000 people; its oocysts are highly resistant to chlorine disinfection.
Question 7: What does a coliform bacteria presence in a distribution system sample most likely indicate?
- Excessive chlorine dosing
- A potential pathway for fecal contamination or inadequate disinfection (Correct answer)
- Normal background levels acceptable for drinking water
- High mineral content in source water
Correct answer: A potential pathway for fecal contamination or inadequate disinfection
Total coliform presence indicates either inadequate disinfection, a cross-connection, or a breach in system integrity that could allow pathogens to enter.
HIC Water Quality & Sampling 3
A drinking water sample tests positive for E. coli.
What is the required public notification timeline for this acute MCL violation?