PUBH 6011 Final Actual questions and answers with 100% accuracy(VERIFIED BY PROFESSOR)

Understand the major function of cells

Cell differentiation: in bone marrow, adult stem cell can reproduce and splits to either myeloid or lymphoid progenitor, which can then differentiate into many kinds of cells

Homeostasis and cell injury: many adverse biological effects occur when cells are damaged, damage can be to any part of the cell, causes can be infectious agents, oxygen deprivation, trauma, chemicals, nutritional imbalances

Apoptosis vs. Necrosis

Apoptosis- programmed cell death, active, orderly and organized; requires energy a plan and enzymatic degradation of proteins/dna; produces neatly packed cell fragments that are recycled

Necrosis- cell damage and death, passive and disorderly; produces cell debris

Bacteria vs Virus

bacteria

-prokaryotic cell

-most are free living

-relatively large

-antibiotics used to kill

Virus

-not a living cell (genes packaged in protein shell)

-intracellular parasite

-1/1000 size of a bacteria

-vaccine used to prevent

-antiviral treatment

protein synthesis

the formation of proteins by using information contained in DNA and carried by mRNA

DNA transcription RNA translation protein

Role of DNA

storing information, copying information, and transmitting information

Role of mRNA in protein synthesis (transcription)

single stranded messenger that carries the genetic information copied from DNA in the form of a series of a three base code of words.

Role of tRNA in protein synthesis (translation)

is the key to diciphering the code words from mRNA

Role of ribosomes in protein synthesis

ribosomes are complexes made of ribosomal RNA and protein

ribosomes carry out protein synthesis in two locations

a minute particle consisting of RNA and associated proteins found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.

Explain how biological and genetic factors can influence our response to environmental hazards

mutagens- pollutants in the environment that can enter the body and directly change your DNA sequence (ex. the chemicals in cigarette smoke can cause cancer)

Gene-gene interactions: ○ occur when pollutants in the environment do not change your DNA sequence, but rather cause a chain reaction that affects the functioning of one gene that then affects the functioning of another gene

■ Ex. Regularly drinking way too much alcohol can cause the gene TACE not to produce enough of its protein. TACE protein is supposed to help the MTHFR gene make enough of its protein. Too little MTHRF protein changes the level of folate in our blood, and low folate levels may cause depression.

○ Transcription factors - pollutants in the environment can indirectly affect the DNA sequence by altering transcription factors, which are responsible for starting the process of using genes to make proteins that are needed for different functions in the body

■ Ex. stress can change the amount of proteins made by genes involved in your immune system and therefore, you may get sick more easily when you're stressed

○ Epigenetics - the environment can alter your health by affecting the proteins that turns genes on or off

■ Half the genes that cause familial or inherited cancer are turned off when pollutants in the environment affect these proteins. Because they are turned off, these genes cannot suppress tumor formation or repair DNA

Explain the role of the microbiome and its role in disease prevention

Microbiota → gut microbiota

- Involved in basic human biological processes

- Chronic disease have been associated with the human microbiota

Antibiotics can disrupt microbiota

The bacteria in the microbiome help digest our food, regulate our immune system, protect against other bacteria that cause disease, and produce vitamins including B vitamins B12, thiamine and riboflavin, and Vitamin K, which is needed for blood coagulation.

Epigenetics

the study of environmental influences on gene expression that occur without a DNA change

DNA methylation

The addition of methyl groups to bases of DNA after DNA synthesis; may serve as a long-term control of gene expression.

histone modification

adding chemical modifications to proteins called histones that are involved in packaging DNA

micro-RNA (miRNA)

A small, single-stranded RNA molecule that binds to a complementary sequence in mRNA molecules and directs associated proteins to degrade or prevent translation of the target mRNA.

Microlesions

change in 1 bp

substitution

point mutation (silent, nonsense, missense)

frameshift mutations

Macrolesions

chromosome aberrations

- Often caused by effects on mitotic machinery, not DNA

- Change in chromosome structure

- Deletion, duplication, inversion, translocation—may be stable

- Acentric fragments, dicentric chromosomes—usually cell death

change in chromosome number

- aneuploidy

- polyploidy

Why do mutations matter?

● Polymorphisms can change the function of proteins

● Many proteins (e.g., enzymes, receptors) associated with response to chemicals, drugs, and so on

● Effect may be silent, advantageous, or disadvantageous

○ Example: Change in SNP can make people less drug dependent

genotoxic carcinogens

Causes DNA replication errors, point mutations, Chromosomal abberations, also binds to DNA and is irreversible

Nongenotoxic

carcinogens that modify gene expression but do not damage DNA

induce cancer through hormonal effects, cell proliferation, increase change of replication errors, increase number of cells at risk

mutations and cancer

Cancer-causing mutations typically occur in two categories of genes

proto-oncogenes: leading to altered forms of normal cellular genes usually involved in cell signaling and growth control

tumor suppressor genes: whose protein products help regulate proliferation of normal cells- act as a "brake"- or promote programmed cell death (apoptosis)

Three cancer types with highest mortality in the US

1. lung/ bronchus

2. colon/ rectum

3. pancreas

innate vs adaptive immunity

Innate immunity: An individual's genetically predetermined resistance to certain diseases.

Adaptive immunity: Ability of the body to react to specific microbial infection. ANTIGEN SPECIFIC

Antibody-Antigen Interactions

•Complementary fit between antigen and antibody is needed

•The better the fit the better the stimulation of the lymphocytes

Can be multiple antigens on one pathogen cell (can be proteins, sugars, etc), each recognized with a different antibody

Vaccines

dose of a disabled or destroyed pathogen used to stimulate a long-term immune defense against the pathogen. A weakened form of the virus is given to the person so their immune system can build up immunity to the virus.

first pass effect

The initial metabolism in the liver of a drug absorbed from the gastrointestinal tract before the drug reaches systemic circulation through the bloodstream.

Concentration of the drug is greatly reduced before it reaches circulation

role of liver in breaking down food, microbes, and chemical toxins

The largest gland in the body that breaks down nutrients and builds up body tissue. It acts as a storage site for minerals and vitamins. Red blood cells and Kupffer cells (cells that help eliminate harmful microorganisms as they move through the blood) are produced in the liver. Glycogen is also produced in the liver and it is regulated throughout the body. Vital when it comes to metabolic processes and disposal of toxins.

The liver converts fat soluble toxins to water soluble substances that an be excreted.

The enzymatic process to dispose of toxins happens in 2 phases: phase 1 (oxidation) and phase 2 (conjugation).

■ Phase 1: neutralizes toxins or changes the toxic chemical to form activated compounds that will be neutralized in stage 2. This makes toxic chemicals less harmful. Free radicals are produced (too many can damage the liver), the effects of which are reduced by antioxidants.

■ Phase 2: Conjugation pathway causes the liver cells to add another substance to the toxic chemical to make it less harmful. This makes the toxin water-soluble so it can be excreted as bile or urine.

Variability in metabolism

can affect the activity of drugs

dose-response relationship

Relationship between an administered dose and the effect on an organism

majority of response are at mean

- Knowledge of the dose-response relationship establishes:

o Causality — that the chemical has induced the observed effects

o The threshold effect — the lowest dose where an induced effect occurs.

o The slope for the dose response — the rate at which injury builds up.

o Within a population, the majority of responses to a toxicant are similar; however, there are differences in how responses may be encountered - some individuals are susceptible and others resistant. As demonstrated in Animation 1, a graph of the individual responses can be depicted as a bell-shaped standard distribution curve. There is a wide variance in responses as demonstrated by the mild reaction in resistant individuals, the typical response in the majority of individuals, and the severe reaction in sensitive individuals.

○ The variation can be due to genres, nutrition, health status, etc.

● Measures proportion of the population responding at each dose level or level of response at each dose level in controlled settings

Individual vs. population dose relationship

Individual dose response relationship: change in severity of adverse effect with dose (also called dose-effect relationship)

○ Example: Aspirin therapeutic in low dose and super bad in high doses (dose makes the poison)...BUT different ppl are more sensitive to aspirin (or other chemicals) that make the dosage effects vary

Population dose response relationship: change in the proportion of the population responding with dose

○ Different relationships for different effects

○ Shape of curve gives information about population variability and toxicity of the compound

pros and cons of toxicology and epi in determining toxicity

○ Epidemiology:

■ Study of disease rates in human populations with and without exposure to chemical under study

■ Can discover a statistical association between exposure and disease

■ Rarely can establish causal relationship or mechanism of disease causation

○ Strengths

■ Study species of interest

■ Free ranging subjects in their natural environment

○ Limitations

■ Nonexperimental

■ Often qualitative

■ Usually retrospective

■ Often high-dose occupational studies

● Environmental exposures are usually much lower

● May miss diseases of women, the young, or the elderly (if we focus only on the workforce of interest)

■ Subject to confounding and bias

NOAEL and LOAEL

No Observed Adverse Effect Level: Highest dose at which there was not an observed toxic or adverse effect.

Lowest Observed Adverse Effect Level: Lowest dose at which there was an observed toxic or adverse effect.

LD50

the amount of a chemical that kills 50% of the animals in a test population

shows how lethal a dose is

RfD

Reference Dose: Estimated daily dose that is likely to have no appreciable adverse effects during a lifetime exposure

An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral or dermal exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.

slope factor

Value, in inverse concentration or dose units, derived from the slope of a dose-response curve; in practice, limited to carcinogenic effects with the curve assumed to be linear at low concentrations or doses. The product of the slope factor and the exposure is taken to reflect the probability of producing the related effect.

mechanistic studies

■ In Vivo = ADME studies & effects of different dosing levels, durations, or patterns

■ In Vitro = Mutagenic potential, molecular mechanism of actions

■ Strengths:

● Compound-specific information

● Understanding biology should improves

○ Cross-species extrapolation

○ High-dose to low-dose extrapolation

■ Weakness

● Difficult to rule out alternative theories

● Often lack of necessary data for humans

● Scientific disagreement/uncertainty

acute toxicity

adverse effects that occur within a short period after exposure to a toxicant

chronic toxicity

adverse effects that occur some time after exposure to a toxicant or after extended exposure to the toxicant

Define absorption

movement of digested food molecules through the wall of the intestine into the blood

Define distribution

How the drug is transported by the blood to the site of action. It requires adequate cardiac output and tissue perfusion

Define metabolism

The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.

Define excretion

Removal from organisms of toxic materials, the waste product of metabolism and substances in excess requirement

passive diffusion

movement of substances across a semipermeable membrane with the concentration gradient; this process does not require energy

hydrophobicity molecules can readily cross

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

Primary routes of exposure

○ Oral: Leads to first exposure with organ absorption

○ Inhalation: air ways

○ Dermal: skin contact

Four steps of environmental risk assessment

1. hazard identification

2. Dose-response evaluation

3. Exposure assessment

4. Risk characterization

hazard identification

examines the evidence that associates exposure to an agent with its toxicity and produces a qualitative judgment about the strength of that evidence

Dose-response evaluation

*an attempt to quantitatively determine the relationship between exposure to a toxicant and disease.

exposure assessment

the procedure that identifies populations exposed to the toxicant, describes their composition and size, and examines the roots, magnitudes, frequencies, and durations of such exposures

risk characterization

develops estimates of the number of excess unwarranted health events expected at different time intervals at each level of exposure

SDGs (Sustainable Development Goals)

the 2030 agenda is a set of 17 interrelated goals to end poverty, protect the planet and ensure that all people enjoy peace and prosperity.

world met MDG for improved drinking water, but not for sanitation

ground water quality

usually free of contaminants because the soil filters it and often available where needed at little cost

limited volume, essentially irreplaceable once depleted

wellhead protection areas protects groundwater by keeping any activity that can contaminate the groundwater out of the area where the aquafor is being accessed

surface water quality

surface water requires extensive treatment before use, and drinking water often competes with other uses of surface water such as irrigation, industrial use, fisheries, and habitat

Clean water act

(CWA, 1972) set maximum permissible amounts of water pollutants that can be discharged into waterways; aims to make surface waters swimmable and fishable

NPDES

Was created by the CWA. Sets water quality standards for surface water by governing what you can put in. It is against the law to discharge a pollutant from a point source without a permit.

Still require a permit to dump in navigable waterways, streams and intrastate lakes, coastal waterway, freshwater wetlands.

1987 amendment: attention to stormwater runoff "non-point" sources

Safe Water Drinking Act (1974)

set maximum contaminant levels for pollutants in drinking water that may have adverse effects on human health

requires the EPA to publish a list of unregulated contaminants of concern list (CCL)

Contaminants of concern

Specific contaminants that are of concern for human health for the exposure pathway

EPA must show:

1. That the contaminant adversely affects human health

2. that it is known or substantially likely to occur in public water systems with a frequency and at levels of public health concern

3. that regulation of the contaminant presents a meaningful opportunity for health risk reduction

MCLGs

Maximum Contaminant Level Goals (nonenforceable): a nonenforceable publish health goal

• After reviewing health effects studies, the EPA sets a Maximum Contaminant Level Goal (MCLG)—a nonenforceable public health goal.

• At level where no adverse effect expected

• Drinking water consumption compared with an oral reference dose (RfD) and other potential sources of exposure to contaminant

• MCLG for suspect carcinogens set at zero

• Does not consider ability to measure or treatment technology

• Once the MCLG is established, the EPA sets an enforceable standard called a Maximum Contaminant Level (MCL).

• Based on technical feasibility and cost

• Set as close to the MCLG as possible

• If there is no reliable method to measure contaminant at a low enough level, the EPA may set a treatment technique (TT) instead of an MCL—still enforceable.

• Technology or procedure (performance standard) that must be followed

• Example is the lead and copper rules that monitor tap water and compare it with an action level, rather than an MCL

MCLs

Maximum contaminant levels (enforceable): maximum amount of any water pollutant that might adversely affect human health

primary vs secondary drinking water standards

NPDWR: primary are legally enforceable standards (MCLs and treatment techniques)

NSDWR: unenforceable guidelines (cosmetic effects and aesthetic effects)

explain typical water treatment processes in developed countries including disinfection by-products

1. Screen, usually surface water only

2. Flocculation / coagulation: chemicals that are used to clump fine particles together. Particles stick and grow big enough and eventually settle out.

3. Sedimentation: all the particles stuck to flock are removed through gravity

4. filtration: activated charcoal takes chemicals and other things out of water by binding to them

5. disinfection

6. storage

7. Distribution of water

Disinfection

Chlorine: cheap effective, produces a number of by-products

Ozone: expensive, no residual

Chlorine dioxide: no residual

Explain water availability and treatment challenges in developing countries

○ Arsenic in drinking water, need to dig deeper wells; filtration techniques; mark high arsenic wells

■ Bangladesh example of attempts to reduce surface waterborne disease...dug tube wells...lead to massive arsenic exposure in the population (Persons w/poor nutrition esp sensitive to arsenic effects)

■ 2/3rds of wells have high arsenic levels

○ Water collection --> a good source if don't live closer to drinking water. It influences hygiene practices. Less likely to practice hygiene the farther an individual is away.

○ Water availability --> proportion of population using an improved drinking water has improved but disparities exist especially between rural and urban.

○ Treatment challenges : Done at household level.

■ Chlorination - appropriate for use in areas where drinking water is taken from muddy ponds or rivers.

■ Ceramic and Biosand Filters - unknown effectiveness against viruses, lack of residual protection that can lead to recontamination, the need for user education to keep the filter and receptacle clean, and potential slow flow rates.

■ SODIS- the need for pretreatment of turbid water, limited volume of water that can be treated at once, length of time required to treat water, and the supply of plastic bottles required.

■ Boiling- potential for recontamination after boiling and prior to consumption is high. Water must be consumed in 24 hours.

point source vs. non-point source pollution

Point source pollution is when contaminants enter a water supply from a single identified source

non-point source pollution is when contaminants cannot not be traced to a source (example: animal manure/ stormwater)

Biological Oxygen Demand (BOD)

The amount of oxygen needed by microorganisms to decompose biological wastes into carbon dioxide, water, and minerals.

Higher BOD is associated with lower water quality because the nutrients present provide the ingredients for eutrophication and lowering of oxygen levels in a body of water. If oxygen levels get too low the water body can become hypoxic or even anoxic.

apply systems thinking to explain why marine "dead zones" develop

○ Hypoxia - Low Oxygen.

○ Anoxia- no oxygen.

○ Dead zones--> places where low oxygen is present. Occurs due to waste water treatment, runoffs from agriculture that results in high nutrients ( nitrogen and Phosphorous) in the water--> causes eutrophication---> bacteria breaks down algae and due to abundance of algae increases metabolization--> depletes the oxygen in the water.

Explain the function of each stage of a wastewater treatment facility.

Coming out of your house—>connected to a larger sewer system & wastewater treatment facility.

1. Primary: First step is to run it through coarse screens- capturing grit. Grits goes to landfill by truck

2. Primary sedimentation (aka Sedimentary tanks) - gravity + time works to separate larger products --> get sewage sludge out of it and liquid is passed on to the next stage

3. Secondary (aeration tanks): Bacteria are breaking down products- (aerobic bacteria) as a result compressed air is used. some of the sludge is also returned..hence SECONDARY TREATMENT

4. Final settling Tank—>sludge again is collected and then get treated water.

5. Sometimes can go to tertiary treatment where the water is disinfected. Tertiary treatment may be used to remove nutrients or reclaim water

6. Sludge Disposal (8 million tons of sludge a yr) --- 60% is used in fertilizer and soil amendments Landfill Incineration Ocean dumping—now banned in the United States

7. Treated waste water: Discharged to receiving body (river, lake, etc.) back into environment Used for irrigation Farm land, municipal parks, golf courses, and so on Advantages Return nutrients to soil Cheap irrigation Recharge groundwater Concerns: bacteria, metals, and so on

Explain the challenges of wastewater management in developing countries.

Challenges arise due to lack of infrastructure, and sanitation. The size of many countries and significant rural populations makes it difficult to implement a sewer system. In regards to sanitation, there needs to be intervention at community level (changing behavior), access to sanitation facilities not just in households, and resources such as money.

Describe the types of interventions to address water, sanitation and hygiene (WASH) as it relates to the global burden of disease.

Water- drinkable water

■ Intervention: piped water into dwelling, yard, or plot, public tap or standpipe, protected dug well (groundwater), rainwater collection, protected spring water.

Sanitation refers to getting rid/maintaining human waste.

■ Intervention: composting toilet, pit latrine with slab, ventilated improved pit (VIP) latrine, Flush or pour-flush to: --> piped sewer system, septic tank, pit latrine.

Hygiene - thorough handwashing before eating and after using the toilet

■ Intervention: Need Access to community water systems, Sanitation facilities, household-level and materials and technologies

■ Intervention: changes in behavior practices---> social marketing, school programs, community participation and mobilization.

■ Intervention: enabling environments---> Policy improvements, community organizations, Institutional strengthening, Financing and cost recovery, Public-private partnerships.

■ All interventions must occur to improve hygiene.

It reduces Diarrhea among children as well as contamination of food and water. Diarrheal episode per child per year is highest among children who are 6-11 months.

Explain the fecal-oral route of disease transmission and preventative measures.

Feces can spread through fluids, fingers, files, and Fields/ Floors which can contaminate the food or directly sicken the child.

Sanitation can block fecal oral route. Transmission from fluid can be blocked via clean water supply. Transmission via Fingers, Files, Field/floors, and from food to a child can be blocked hygiene/ handwashing.

Explain the role of the various regulatory agencies responsible for food safety

o USDA's Food Safety and Inspection Service (FSIS): meat, poultry; eggs

o FDA's Center for Food Safety and Applied Nutrition (CFSAN): covers everything else

o EPA's Office of Prevention, Pesticides and Toxic Substances (OPPTS): pesticides

o CDC's Food Safety Office: foodborne infections

HACCP (Hazard Analysis and Critical Control Points)

■ Systematic approach to food safety through prevention, rather than inspection offinal product

■ Origins in systems analysis and NASA—now used worldwide for food safety

■ Map production process and identify "critical control points"

■ Thorough record keeping critical to verification and continuous improvement

■ FDA HACCP Guidance

Local Government Role in Food Safety

■ Inspections of food-producing establishments by local health departments is a key public health measure.

■ For example, the Washington, DC, Health Regulation and Licensing Administration includes the Food Safety and Hygiene Inspection Services Division.

● Responsible for inspection of the city's 4,700 food establishments, including boarding homes, dairies, delicatessens, bakeries, candy manufacturers, grocery stores, retail markets, ice cream manufacturers, restaurants, wholesale markets, mobile vendors, and hotels

● The staff for the program includes 17 sanitarians, two supervisors, a program manager, and a food technologist

DC Health Regulation and Licensing Administration

■ Inspect for proper handling and preparation and other food safety practices as well as potential health hazards

■ Violations can be corrected on site (COS) or within a specified period—inspected again to confirm

■ Understanding DC Food Safety Reports

Salmonella source

Raw and undercooked eggs, poultry, meat, fish; unpasteurized milk.

often associated with eggs or any egg-based food, salads (such as tuna, chicken or potato), poultry, beef, pork, processed meats, meat pies, fish, cream desserts and fillings, sandwich fillings, raw sprouts, and milk products.

Salmonella health effect

The bacteria are spread through indirect or direct contact with the intestinal contents or excrement of animals, including humans.

Salmonella protective measures

bacteria grow at temperatures between 41-113F. They are readily destroyed by cooking to 160F and do not grow (but do survive) at refrigerator or freezer temperatures.

Campylobacteriosis source

■ caused by consuming food or water contaminated with the bacteria Campylobacter jejuni, which is commonly found in the intestinal tracts of healthy animals (especially chickens) and in untreated surface water.

■ Raw and inadequately cooked foods of animal origin and non-chlorinated water are the most common sources of human infection (e.g., raw milk, undercooked chicken, raw hamburger, raw shellfish).

Campylobacteriosis symptoms

Fever, headache, myalgia --> severe abdominal pain --> bloody/watery diarrhea

3-7 day duration

Campylobacteriosis protective measures

■ The organism grows best in a reduced-oxygen environment; is easily killed by heat (120F); is inhibited by acid, salt, and drying; and will not multiply at temperatures below 85F.

■ Preventive measures for Campylobacter infections include pasteurizing milk; avoiding post-pasteurization contamination; cooking raw meat, poultry, and fish; and preventing cross-contamination between raw and cooked or ready-to-eat foods.

infection vs intoxication

infection is microbes grown in GI tract and can become a systemic infection often causing fever

intoxication is microbes located in food that produce toxins and have rapid onset

○ Infection vs. intoxication

■ Salmonella, Campylobacter, E. coli, and Listeria bacteria in food cause food infection.

■ Staphylococcus and Clostridium botulinum bacteria produce a toxin (or poison) as a by-product of growth and multiplication in food and cause food intoxication.

○ Salmonella and Campylobacter are two of the most common sources of human foodborne disease found in CDC FoodNet program

● Explain issues/conditions that challenge food safety and some basic food safety practices

○ Types of Violation in Food Safety Inspection

■ Imminent health hazards: violations that are a significant threat or danger to health; these violations require immediate correction or immediate closure of the establishment and can range from operating without hot water, severe temperature abuse of food, or severe vermin infestation, to the failure of a certified food manager to be on duty during hours of operation

■ Foodborne illness risk factors: defined by CDC and include food from non-approved sources, inadequate cooking temperatures, improper holding temperatures, cross-contamination, and poor personal hygiene

■ Good retail practices: systems to control basic operational and sanitation condition within a food establishment; some examples are pest control, equipment maintenance, plumbing, water, andphysical facilities

○ Learning About Local Practices

■ In Virginia, all restaurant inspections, including specific citations and reactions, posted online: Virginia Department of Health's Inspection Database

■ DC has searchable database of food inspections: Health Regulation and Licensing Administration

■ Montgomery County, Maryland: Data Montgomery - Food Inspection

solid waste

any discarded material from industrial, commercial, govt, mining and agriculture; including solid, semi-solid, liquid, or contained gaseous material

hazardous waste

Any material that can be harmful to human health or the environment if it is not properly disposed of

Two types:

○ listed or characteristic

■ Listed

● Non-specified sources -> toluene, MEK, etc

● Specific sources -> sludge from steel making plant

■ Characteristic - toxicity, ignitable, reactive, corrosive

Municipal solid waste

the waste materials produced in homes, businesses, schools, and other places in a community

■ EPA does not manage at household level, but regulates landfills, etc

Resource Conservation and Recovery Act (RCRA, 1976) History

Times Beach, MO

● Russel Bliss (farmer who was trying to tame the dust on his roads) sprayed waste oil from Pharma Company on ~23 miles of road in his town, Times Beach

● Waste oil contained dioxin, which is a toxin

● EPA realized this and declared a health emergency

● RCRA law passed in 1976

● 1982 flood hits Times Beach → CDC recommends to not re-inhabit

● Town is de-incorporated after incinerator burns 250,000 tons of soil in 1995

Resource Conservation and Recovery Act (RCRA, 1976) Scope

● Defined waste as a technical term (see definitions above)

● Main Intention of RCRA: to disincentivize companies from trying to handle their own hazardous waste; how do we prevent accumulation of hazardous waste?

○ If you're doing something that releases hazardous waste, by law, you're not allowed to collect/neutralize it on your own - you MUST send it to an EPA certified waste center so that they can do it

● Exclusions: domestic waste, fossil fuels, mining wastes, oil and gas refining waste, hydrofracking

● Subtitles A-J of the law classify various kinds of RCRA waste:

○ Subtitle C: Hazardous Waste "Cradle to Grave Tracking"

■ "Cradle to Grave" - making sure the hazardous waste from an industrial company actually gets dropped off at an EPA facility

■ Ex - following a truck that is carrying the waste from the factory to the facility to make sure the waste is properly disposed of

○ Subtitle D: Non-Hazardous Wastes (Municipal Landfills, etc)

○ Subtitle F: Fed Responsibilities (waived sovereign immunity)

○ Subtitle I: Underground Storage Tanks

○ Subtitle J: Medical Waste (now under Medical Waste Management Act)

● Other Important Details

○ RCRA waste is way more expensive to dispose of than regular municipal waste

○ Mixtures - if one drop of Hazardous waste in barrel, it's all hazardous waste

○ Cannot store waste for more than 90 days on site

○ You cannot "treat" hazardous waste

Every container MUST be properly labeled for disposal with detail on the contents

Comprehensive Environmental Response Compensation and Liability Act (CERCLA) History

● Love Canal, City of Niagara, NY

○ 1930s-1950s - Hooker Chemicals dumps ~21,000 tons of Toxic waste into land

○ 1953 - City of Niagara buys land from Hooker Chemical for $1 (despite the company disclosing that there are tons of chemicals in that land and advising against the purchase); deed restriction (i.e. deed mentioned that the land was hazardous and restricted homes/schools from being built there)

○ 1960s - homes and schools were built near site

○ 1978 - waste found oozing from the ground

○ President Carter declares Federal Health Emergency

○ 1980 - CERCLA Law Passed

● "Valley of the Drums" near Louisville, KY

○ Publicized Love Canal was suburban neighborhood; valley of the drums was more visual

○ 17,000 openly dumped drums were removed from 13 acres

○ 1966 - several barrels burned for weeks - still ignored

○ 1979 - EPA issues Emergency cleanup

○ 1980 - CERCLA Law Passed

CERCLA Scope

● Details of Law

○ National Priorities List (NPL) - hazardous waste sites based on health hazard ranking system

○ Government responsible parties MUST cleanup

○ Very Tough Law - Polluter Pays

■ Retroactive - all past and current owners liable

■ Strict - liable regardless if all laws of the day were followed

■ Joint and several - one small waste generator can be liable for all

○ Main idea of CERCLA Law: "If you harm the environment and then the environment harms people, YOU will be held responsible for that"; how can we control/manage the hazardous waste that exists and holding entities accountable for it; how do we clean this up

● When a company no longer exists to be held responsible for its waste, EPA pays (so that means the taxpayers) → budget is ~$250 mil/year, but we need a LOT more to actticually make progress

Superfund Amendment Reauthorization Act (SARA) History

● Bhopal, India - 1984

○ Former DOW chemicals had a Carbide Pesticide plant in India

○ "Worst Industrial Accident" in history - at midnight, 42 tons of Methyl Isocyanate (MIC) reacts with water, over pressurized tank, released into the air

○ Thousands of people wake up with burning sensation in eyes, lungs, etc.

○ Death toll under dispute - anywhere from 4,000-25,000

○ 10,000+ with long term effects

● Outrage over Bhopal lead to SARA

Superfund Amendment Reauthorization Act (SARA) Scope

● Details of Law

○ Created Emergency Planning and Community "Right to Know Act" (EPCRA) - citizens have a right to know about chemicals in the community

○ Requires emergency spill and release response

○ Established the Toxic Release Inventory (TRI)

■ Must report all chemical releases, storage, usage, disposal, (above certain reportable thresholds)

■ Publically available - powerful incentive to reduce emissions

Describe the health impacts for the globalization of waste management (e.g. recycling overseas etc)

○ globalization of waste has detrimental health impacts on the population that lives there - poorly managed - often burned or thrown into a landfill - causes SEVERE pollution

○ These landfills abroad also can sometimes overflow into the surrounding bodies of water with enough rain/floods leading to water pollution

○ All of this pollution leads to large negative health impacts on citizens

● Other Helpful Graphics/slides for this Lecture

American Conference of Governmental Industrial Hygienists (ACGIHA)

American Conference of Governmental Industrial Hygienists

private organization, existed long before OSHA. They can do whatever without being sued.

OSHA (Occupational Safety and Health Administration)

■ To assure so far as possible every working man and woman safe and healthful working conditions ... no employee will suffer diminished health, function or life expectancy from work

■ OSHA - Occupational Safety & Health Admin - legal authority - set rules

■ NIOSH - National Institute of OSH - research to help figure out standards. OSHA decides to pursue what NIOSH suggests

■ OSHA can be sued

○ 1970 - OSHA adopts 1968 ACGIH Exposure Standards

Match any control strategy into the hierarchy of hazard controls

Elimination: controlling the hazard at source

Substitution: replacing one substance or activity with a less hazardous one

Engineering: installing filters, scrubbers, guards

Administrative: procedures to reduce opportunity for exposure

Personal Protective Equipment: respirators, ear plugs

Explain the difference between 8-hour PELs/TLVs, STELs/Ceiling Limits and IDLH

○ We regulate workplace chemicals by setting PELs or TLVs - limit set to protect adult worker exposed 40 hours per week for 40 yrs

■ OSHA - PELs

■ ACGIH - TLVs

■ TLV: threshold limit values...ACGIH limit, so scientifically sound but not legally enforceable

■ PEL: permissible exposure limit: OSHA value

● Both TLVs and PELs use either ceiling limits (max concentration allowed...denoted by c next to number) or 8 hour time weighted average (used for most chemicals with long-term toxicities)

■ Most shifts are 8 hours, avg exposure is compared to standard. If below, you are OK

■ Ceiling limit: highest limit, can't go over this limit ever!

Air Purifying Respirators vs. Supplied Air Respirators

○ Respiratory Fit Test Program is critical for worker education and assuring a proper seal

■ Air Purifying Respirators - must use the nearby air (never use in low oxygen, highly hazardous or unknown environments)

● Disposable Masks Half Mask Full Facepiece Gas Mask

■ Supplied Air Respirators - comes with their own air supply

● Airline Respirator, Self Contained Breathing Apparatus (SCBA)

● Emergency Escape Only when escape will take time - good for 5-10 min

○ Respirator only protects user and mask protects everyone else

○ Asbestos removal requires encapsulated area, suits with respirators and constant air sampling

Explain the conditions for molds/mildew formation indoors

Molds/Mildews love wet building materials, 68-90F, rel humidity >60%, no air movement

We basically control by keeping humidity between 30-60%

Measuring ventilation is a key aspect of controlling indoor air pollution, chemicals, mold etc

Discuss the various types of physical workplace hazards and approaches to protect workers

Hazardous Noise: NOISE - 8-hr TWA limit is 85 dBA according to ACGIH, Once nerve endings are damaged from too much noise, we lose hearing, Use ear plugs/helmets to protect, We attach a device near the ear to measure noise levels through an 8 hour shift

Confined Space Entry, Have standby worker, alarm horn, emergency SCBA, lifeline to safety harness, gas and fume extractor, Heat Stress, Radiation Workers

■ For penetrable radiation (gamma), your only defenses are: More Time, More Distance, More Shielding

■ Outer covering is mainly for alpha particles that pose a problem only if inhaled

Lasers: can even be used as weapons of mass destruction (Temperature: wet bulb global temperature (WBGT))

All Values in WBGT (wet bulb globe temperature), which takes humidity and solar radiation into account

Name the three industries with the highest fatality "rate"

Construction, transportation/warehousing, agriculture/forestry/fishing/hunting