NEHA Registered Environmental Health Specialist/Registered Sanitarian (REHS/RS) — Questions and Answers

Question 1: What is the main goal of secondary wastewater treatment?

To disinfect the treated water
To remove heavy metals
To reduce the biochemical oxygen demand (BOD) and suspended solids (Correct answer)
To remove large solids

Correct answer: To reduce the biochemical oxygen demand (BOD) and suspended solids

Secondary treatment uses biological processes to further degrade organic matter, reducing BOD and suspended solids in the wastewater.

Question 2: Under the HUD Lead Safe Housing Rule, at what age is a dwelling considered 'target housing' requiring lead hazard evaluation before federally assisted renovation?

Built before 1990
Built before 1950
Built before 1978 (Correct answer)
Built before 1960

Correct answer: Built before 1978

The HUD Lead Safe Housing Rule defines target housing as residential dwellings built before 1978, when lead-based paint was banned for residential use.

Question 3: What does the AQI (Air Quality Index) measure?

The presence of radioactive materials
The temperature of the atmosphere
The concentration of various pollutants in the air (Correct answer)
The amount of carbon dioxide in the air

Correct answer: The concentration of various pollutants in the air

The AQI provides a standardized way to communicate the quality of air based on concentrations of pollutants like ozone, particulate matter, and nitrogen dioxide.

Question 4: What is the public health significance of Anopheles mosquitoes in the United States?

They are vectors of dengue fever only
They transmit Lyme disease
They are the vectors capable of transmitting malaria, though domestic transmission is rare (Correct answer)
They are the primary vectors of West Nile virus

Correct answer: They are the vectors capable of transmitting malaria, though domestic transmission is rare

Anopheles mosquitoes are the vectors of Plasmodium parasites that cause malaria; while locally acquired malaria is rare in the US, Anopheles species are present and can transmit malaria imported by travelers.

Question 5: What is the primary purpose of the groundwater monitoring program required at municipal solid waste landfills?

To monitor surface water runoff quality
To measure rainfall infiltration rates
To measure landfill gas migration
To detect landfill leachate releases that may contaminate groundwater (Correct answer)

Correct answer: To detect landfill leachate releases that may contaminate groundwater

Groundwater monitoring programs at MSW landfills are designed to detect the release of leachate constituents that may indicate contamination of underlying groundwater resources.

Question 6: Which federal agency is primarily responsible for implementing and enforcing environmental health laws in the United States?

Centers for Disease Control and Prevention (CDC)
Occupational Safety and Health Administration (OSHA)
U.S. Environmental Protection Agency (EPA) (Correct answer)
Food and Drug Administration (FDA)

Correct answer: U.S. Environmental Protection Agency (EPA)

The U.S. Environmental Protection Agency (EPA) is the primary federal agency responsible for developing and enforcing environmental regulations to protect human health and the environment.

Question 7: What is the 'variance' process in environmental health regulation?

The difference between permitted and actual discharge levels
A formal exemption allowing a regulated entity to deviate from a specific regulatory requirement (Correct answer)
A penalty assessed against violating facilities
An appeal of an enforcement action

Correct answer: A formal exemption allowing a regulated entity to deviate from a specific regulatory requirement

A variance is a formal regulatory mechanism allowing a regulated entity to deviate from a specific standard or requirement, typically granted when strict compliance would create undue hardship and an alternative provides equivalent protection.

Question 8: Under the EPA Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), what is required before a pesticide can be legally sold or distributed in the United States?

EPA registration following safety and efficacy review (Correct answer)
State-level approval only
Manufacturer self-certification
Approval by the FDA

Correct answer: EPA registration following safety and efficacy review

FIFRA requires that all pesticides undergo EPA registration, which involves a comprehensive review of the pesticide's safety, environmental fate, and efficacy data before it can be legally sold.

Question 9: Secondhand smoke in residential environments is classified by the EPA as which category of carcinogen?

Group A (known human carcinogen) (Correct answer)
Group D (not classifiable)
Group B1 (probable human carcinogen)
Group C (possible human carcinogen)

Correct answer: Group A (known human carcinogen)

The EPA classifies environmental tobacco smoke (secondhand smoke) as a Group A known human carcinogen based on sufficient epidemiological evidence of lung cancer causation.

Question 10: Sub-slab depressurization (SSD) is the most common active mitigation technique for which indoor environmental hazard?

Radon gas (Correct answer)
Carbon monoxide
Mold spores
Volatile organic compounds

Correct answer: Radon gas

Sub-slab depressurization reduces indoor radon by creating negative pressure beneath the foundation slab, venting radon-laden soil gas to the outdoors before it enters the home.

Question 11: What is the significance of Aedes aegypti in public health?

It transmits West Nile virus only
It is the primary vector of dengue, Zika, chikungunya, and yellow fever (Correct answer)
It is the primary vector of Lyme disease
It is a non-disease-transmitting nuisance mosquito

Correct answer: It is the primary vector of dengue, Zika, chikungunya, and yellow fever

Aedes aegypti is a highly competent vector responsible for transmitting dengue, Zika virus, chikungunya, and yellow fever, making it one of the most dangerous mosquitoes to public health.

Question 12: The lead dust clearance standard after renovation, repair, and painting (RRP) work in pre-1978 homes requires floor dust samples to contain no more than how many micrograms of lead per square foot?

100 µg/ft²
10 µg/ft² (Correct answer)
5 µg/ft²
40 µg/ft²

Correct answer: 10 µg/ft²

EPA's RRP Rule requires post-renovation floor dust wipe samples to contain no more than 10 µg/ft² of lead to pass clearance testing.

Question 13: What is the purpose of a 'Preliminary Site Investigation' (PSI) at a potentially contaminated property?

To conduct laboratory analysis of soil and groundwater samples
To obtain a building permit for site development
To gather existing information and conduct site reconnaissance to determine whether a recognized environmental condition exists before committing to detailed investigation (Correct answer)
To conduct full remediation of identified contamination

Correct answer: To gather existing information and conduct site reconnaissance to determine whether a recognized environmental condition exists before committing to detailed investigation

A PSI (also called Phase I ESA) reviews historical records, databases, and site conditions to identify recognized environmental conditions that may indicate contamination, guiding decisions about whether further investigation is needed.

Question 14: What environmental health concern is associated with open dumping of solid waste?

Increased property values nearby
Vector breeding, groundwater contamination, and fire hazards (Correct answer)
Excessive noise from trucks
Improved soil fertility

Correct answer: Vector breeding, groundwater contamination, and fire hazards

Open dumps create numerous environmental health hazards including vector breeding sites (rodents, insects), leachate contamination of groundwater, methane fire risks, and air pollution.

Question 15: Carbon monoxide (CO) is dangerous in enclosed spaces primarily because it competes with oxygen for binding to which blood protein?

Myoglobin
Albumin
Hemoglobin (Correct answer)
Fibrinogen

Correct answer: Hemoglobin

CO binds to hemoglobin with about 240 times greater affinity than oxygen, forming carboxyhemoglobin (COHb) and impairing oxygen transport to tissues.

Question 16: In public health, what is a 'vector' in the context of disease transmission?

A type of personal protective equipment
A pathogenic microorganism
An organism that transmits a pathogen from one host to another (Correct answer)
A chemical disinfectant used in pest control

Correct answer: An organism that transmits a pathogen from one host to another

A vector is a living organism, typically an arthropod such as a mosquito or tick, that transmits a pathogen between infected and uninfected hosts.

Question 17: What is a 'complaint investigation' in environmental health practice, and what triggers one?

An investigation initiated in response to a citizen, tenant, or employee report of a potential environmental health hazard or regulatory violation (Correct answer)
A self-initiated routine inspection scheduled by department policy
A federally mandated annual review of permitted facilities
An investigation initiated only when violations are discovered during routine inspections

Correct answer: An investigation initiated in response to a citizen, tenant, or employee report of a potential environmental health hazard or regulatory violation

A complaint investigation is initiated when a member of the public, worker, or other party reports a suspected environmental health hazard or violation; the complaint provides the trigger and direction for the investigative response.

Question 18: What does the Lead and Copper Rule (LCR) under SDWA require water systems to do?

Test all household plumbing annually at government expense
Monitor drinking water at customer taps and take action levels if lead or copper concentrations exceed regulatory thresholds (Correct answer)
Prohibit the use of copper pipes in new construction
Remove all lead pipes within 30 days of detection

Correct answer: Monitor drinking water at customer taps and take action levels if lead or copper concentrations exceed regulatory thresholds

The Lead and Copper Rule requires public water systems to monitor tap water at customer homes and take specific actions including corrosion control treatment, public education, and lead service line replacement when action levels are exceeded.

Question 19: What is the primary source of ground-level ozone, a major component of smog?

Industrial emissions
Motor vehicle exhaust (Correct answer)
Agricultural activities
Natural sources like volcanoes

Correct answer: Motor vehicle exhaust

Ground-level ozone is primarily formed from nitrogen oxides (NOx) and volatile organic compounds (VOCs) emitted by motor vehicles and industrial activities when they react with sunlight.

Question 20: Which life stage of mosquitoes is targeted by larvicides such as Bti (Bacillus thuringiensis israelensis)?

Pupae emerging from water
Adult mosquitoes in flight
Larvae in aquatic habitats (Correct answer)
Eggs on the surface of water

Correct answer: Larvae in aquatic habitats

Larvicides like Bti are applied to standing water to kill mosquito larvae before they develop into adult disease-transmitting mosquitoes.

Question 21: What is the primary health effect of carbon monoxide (CO) poisoning?

Respiratory irritation and chemical pneumonia
Oxygen deprivation (tissue hypoxia) caused by CO binding to hemoglobin with greater affinity than oxygen (Correct answer)
Liver damage from metabolic disruption
Kidney failure from direct nephrotoxicity

Correct answer: Oxygen deprivation (tissue hypoxia) caused by CO binding to hemoglobin with greater affinity than oxygen

Carbon monoxide binds to hemoglobin approximately 250 times more strongly than oxygen, forming carboxyhemoglobin that cannot carry oxygen, causing tissue hypoxia, which can result in neurological damage or death.

Question 22: Which mold genus is most commonly associated with water-damaged buildings and classified as a 'black mold' of public health concern?

Stachybotrys chartarum (Correct answer)
Cladosporium herbarum
Aspergillus niger
Penicillium notatum

Correct answer: Stachybotrys chartarum

Stachybotrys chartarum is the mold commonly called 'black mold' and is associated with chronic water damage; it produces trichothecene mycotoxins of public health concern.

Question 23: What does pH measure in water quality?

The concentration of heavy metals
The amount of dissolved oxygen
The acidity or alkalinity of water (Correct answer)
The temperature of water

Correct answer: The acidity or alkalinity of water

pH is a measure of how acidic or basic (alkaline) water is, with values ranging from 0 (most acidic) to 14 (most basic).

Question 24: What Integrated Pest Management (IPM) principle should be applied first before considering pesticide application?

Apply pesticides on a fixed schedule
Identify the pest and use non-chemical prevention and control methods first (Correct answer)
Treat the entire area regardless of pest presence
Apply the most toxic pesticide available

Correct answer: Identify the pest and use non-chemical prevention and control methods first

IPM principles prioritize accurate pest identification followed by non-chemical strategies such as sanitation, exclusion, and habitat modification before resorting to pesticide application.

Question 25: What is the difference between 'qualitative' and 'quantitative' risk assessment in environmental health?

Qualitative is more accurate than quantitative
Qualitative assessment describes risk in narrative terms; quantitative assessment provides numerical estimates of risk probability (Correct answer)
They refer to different phases of the risk assessment process
Quantitative is only used for air quality while qualitative is used for water quality

Correct answer: Qualitative assessment describes risk in narrative terms; quantitative assessment provides numerical estimates of risk probability

Qualitative risk assessment characterizes risk descriptively (high, medium, low) while quantitative risk assessment generates numerical estimates (e.g., one additional cancer case per 100,000 exposed) using statistical models and dose-response data.

Question 26: Which of the following contaminants is often responsible for causing algal blooms in water bodies?

Pesticides
Chlorine
Heavy metals
Nitrates and phosphates (Correct answer)

Correct answer: Nitrates and phosphates

High levels of nitrates and phosphates in water can cause excessive algae growth, leading to harmful algal blooms and water quality issues.

Question 27: What is the primary environmental concern associated with sanitary landfills?

Air noise pollution
Light pollution
Electromagnetic interference
Leachate contamination of groundwater (Correct answer)

Correct answer: Leachate contamination of groundwater

Leachate, the liquid that percolates through landfill waste, poses a significant risk of contaminating underlying groundwater supplies.

Question 28: What is the 'enforcement discretion' principle in environmental health regulation?

The mandate to pursue criminal charges for all violations
The authority of regulators to prioritize enforcement resources and determine appropriate responses based on severity, good faith, and compliance history (Correct answer)
The prohibition of informal compliance assistance
The requirement that all violations must be penalized equally

Correct answer: The authority of regulators to prioritize enforcement resources and determine appropriate responses based on severity, good faith, and compliance history

Enforcement discretion allows regulatory officials to prioritize cases by severity, consider factors such as good-faith compliance efforts and history of violations, and select the most appropriate enforcement response.

Question 29: Which of the following is the most common method used to disinfect drinking water?

Fluoridation
Filtration
Chlorination (Correct answer)
Boiling

Correct answer: Chlorination

Chlorination is the most widely used method to disinfect drinking water, killing bacteria, viruses, and other pathogens.

NEHA Registered Environmental Health Specialist/Registered Sanitarian (REHS/RS)

The REHS/RS credential exam tests environmental health specialists on surveillance, inspections, investigations, compliance review, and public communication across food safety, water, waste, and hazardous materials domains.

225

Questions

220 min

Time Limit

68%

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