Week 4: Industrial Hygiene, Environmental Management, and Environmental Ethics Flashcards
What are the 2 types of doses?
Internal dose and biologically-effective dose
Define internal and biologically-effective dose.
Internal Dose: the amount of a substance crossing one of the route barriers into the body
Biologically-effective dose: the amount of a substance reaching a target organ
What is the mathematical formula for dose?
Dose: concentration x exposure duration x rate at which material reaches body boundary
Define exposure science. What is the difference between industrial hygiene evolved in workplaces and exposure science?
Exposure science: modern field focused on exposure assessment in both workplace and environment
IH (occupational hygiene) evolved from measuring to controlling exposures and workplace risks
Exposure scientists measure/quantify exposures in general population (often in research setting); results used for risk assessment, public health policymaking
What do industrial hygiene and exposure both try to do? What are 4 reasons why it is important?
Both try to quantify exposures
Important for:
Assessing potential problems
Directing preventive efforts, monitoring success
Checking compliance with regulations
In research, quantifying association between exposures and health outcomes
List the steps of the IH paradigm. What are 4 details about anticipation and recognition?
IH paradigm: anticipation, recognition, evaluation, control; anticipation, 1st step
Hygienist gathers info. on site history, process, job titles, materials safety data sheets on chemicals used
Develops preliminary list of potential hazards: safety hazards (e.g., inappropriate chemical storage), health hazards: physical (e.g., repetitive motion), chemical (acute, chronic hazards), biological (e.g., blood-borne pathogens), environmental (threats to public safety [e.g., chlorine tank rupture], health [e.g., solvents leaking to groundwater], or welfare, ecological damage)
Recognition phase: site visit/walk-through (visual inspection), review health and safety programs, identify
workers at risk; write-up, incl. hazard eval. plan
What are 3 details about evaluation?
Quantify exposure through sampling/measurement: area sampling: in a room, in vicinity of some workers, personal sampling: in breathing zone of individuals, biological sampling/biomarkers: body fluids, breath, hair
Population sampling: identify/enumerate all who could be sampled, choose sampling strategy (census of all, stratified, convenience [biased], worst-case)
Instruments:
Direct reading: near real-time; available for many physical hazards (e.g., temp., noise, humidity, UV, radiation) and pollutants (gases, vapors, airborne particles)
Sample collection: collects sample (e.g., volume of air) for laboratory analysis; increasing volume increases contaminant mass collected, sensitivity for low levels
When are sample collection instruments used?
Used instead of direct reading if multiple pollutants or additional laboratory analyses needed
Define active sample collection. Give the formulas and pros/cons.
Active: pump draws air through absorbing medium
Total volume air sampled = flow rate x sampling duration
Contaminant concentration = mass collected / volume of air sampled (e.g., ug/m3)
Versatile, sensitive, specific for contaminants analyzed in laboratory, but can be bulky, noisy, need batteries
Define passive sample collection. Give the formulas.
Passive: uses diffusion (concentration gradient) instead of pump to collect air in absorbing medium that removes compound by reaction or absorption
Flow rate of air to surface computed using Fick’s law;
Volume sampled = flow rate x sampling time;
Concentration = mass / volume (e.g., ug/m3)
Out of active and passive sample collection, which is used for biomonitoring?
Passive sample collection
What is control? What are 6 control strategies?
Control of workplace hazards = primary prevention
Substitution: replace hazardous materials/processes w/less hazardous (e.g., replace benzene w/toluene)
Isolation: engineering controls to limit access to hazardous materials (e.g., enclosed solvent washer)
Ventilation: introduce fresh air, use exhaust hoods
Administrative controls: policies/procedures to reduce risk (e.g., lockout tag-out, worker rotation)
Protective devices (e.g., two-handed “On”)
Personal protective equipment (PPE) (e.g., respirators, gloves, safety glasses, hardhats, etc.) – least preferable of all control strategies
Define exposure science.
Exposure science: the study of human contact with chemicals, physical, or biological agents in the environment
What are the 3 principal routes of exposure? Give 4 details.
Inhalation, ingestion, and dermal
These routes of exposure are different from the exposure pathway, or the path by which the contaminant moves from a source to a human receptor
For example, pesticide exposures in children may come from several pathways
Children may ingest pesticides from residues present on food (a dietary pathway); they may get pesticides on their skin from their parents’ contaminated clothing if the parents work on a farm (a take-home pathway); if spraying takes place close to their home, they may inhale pesticide particles or vapors (a drift pathway)
These pathways differ substantially and each requires entirely different assessment and control strategies to reduce exposure.
Define imputing/modeling as an exposure assessment. List 2 examples and exposure scenarios.
Imputing/modeling: indirect, used when direct measurements lacking or only partial data
Time-location studies, dietary exposure estimation
Exposure scenarios: typical individuals, activities, locations, available data; inexpensive, used in risk assessment
Job-exposure matrix
Contrast aggregate and cumulative exposure assessment.
Aggregate: assessing simultaneously all routes and pathways for a particular compound (e.g., agricultural worker’s exposure to particular pesticide through inhalation, dermal absorption while working, and at home [residues on food, contamination on clothing])
Cumulative: aggregate exposure to series of compounds (or nonchemical exposures, e.g., malnutrition) with similar biological mechanisms (e.g., organophosphate pesticides, inhibit acetylcholin-esterase needed for nerve signal conduction)
What are 2 ingestion assessment challenges?
Duplicate diet studies: directly measure dietary contaminant intake; duplicate sample of all food eaten by subject, weighed, homogenized, analyzed; difficult on large scale
Food diary studies: subjects record foods, portion sizes; researcher purchases at store, measures concentrations; conc. x amount eaten (from diary) = exposure; cheaper, more subjects but measurement error (foods eaten not measured)
What are 2 dermal absorption assessment challenges? Give 2 details.
Patch sampling: adsorbent patches on skin, clothes; exposed during activities, removed, measured, summed over all exposed areas of body for total exposure
Tape stripping: removes single layer of skin cells
Both sample only portion of exposed skin
Fluorescent tracer method reveals where on skin exposed
What are 4 regulatory agencies and what do they do?
OSHA: assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education and assistance
EPA: responsible for maintaining and enforcing national standards under a variety of environmental laws, in consultation with state, tribal, and local governments.
FDA: responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, dietary supplements, prescription and over-the-counter pharmaceutical drugs, vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices, cosmetics, animal foods & feed and veterinary products
USDA: aims to meet the needs of farmers and ranchers, promote agricultural trade and production, work to assure food safety, protect natural resources, foster rural communities and end hunger in the United States and internationally
Define ethics and morals.
Ethics: more formal view of morality; in professional life, a normative process of deciding what we ought to do or not do
Morals: core beliefs about what is important, valuable, or right with regard to conduct, character
What are the 3 key modern ethics principles primary to environmental health?
Scientific integrity (honesty, truth-telling): when a risk is discovered that requires public attention, EH professionals should advocate their concerns
Justice: in public health, usually framed as social justice, highlighting differences that affect health status unfairly
Welfare: social effort designed to promote the basic physical and material well-being of people in need
What are 4 environmental health ethics controversies?
Public regulation of behavior vs. individual freedom: extent to which government (and employers) may appropriately manage behavior, factors affecting health
Nondisclosure vs. right to know
scientific research and public health advocacy:
Scientists/academics need to maintain objectivity, are cautious in making claims about policy implications of data
Environmental justice: some policies/practices harm certain groups unfairly
Common resources: poorly managed common resources quickly depleted
What are 4 climate change ethical challenges?
Future generations: warming levels reached now will persist 1000’s of years; most of globe uninhabitable for mammals by 2300 (McMichael & Dear 2010)
Discounting: must control climate change now; non-linear approach needed for valuing future risks
Technological prospects: costs of scaling up existing alternative energy technologies manageable
(Mountford 2014), but disagreements on safety (e.g.,
nuclear, geoengineering)
Consumption: must limit; some countries maintain health at lower consumption levels
What are the 3 aspects of an exposure profile? Define each.
Frequency, intensity, and duration of exposure
Frequency: how many times an individual/group come into contact with a contaminant
Intensity: the dose of the contaminant that contact has been made with
Exposure: the amount of time the individual/group comes into contact with
What are 2 details about frequency, intensity, and exposure?
Some contaminants are cleared at lower levels, toxic at higher ones
Important questions: regular or episodic (frequency), peak concentration (intensity), and short or long duration (exposure)
What are the 3 exposure scenarios from the EPA?
Acute: ingestion, skin absorption or breathing for 24 hrs or less; poisoning and other immediate effects
Chronic: repeated episodes from same routes less than 10% of lifespan; cancer, chronic lung damage, etc.
Subchronic: repeated episodes, one or more routes, greater than 30 days for up to 10% of lifespan
Define direct measurements as an exposure assessment method. List the types of environments it can be used in. Give examples of personal exposures and biomarkers.
Direct measurements (expensive, more accurate)
Environmental: fixed locations/area sampling
Personal exposures: portable devices; reflects time, location, behavior; video exposure, monitoring;
Biomarkers (gold standard): parent compounds or metabolites in body fluids, tissues; proves absorption, reflects bioavailability; genetic differences
