environment midterm

Define environmental justice through fair treatment and meaningful involvement.

Achieving environmental equality that recognizes everyone’s needs and never makes any party feel lesser or unincluded. Meaningful involvement means people can actually influence decisions that affect their environment and health.

Who benefits? Shareholders, executives, consumers, and well-protected communities gain the profits, cheap products, and economic growth, while the costs stay with the people living closest to the pollution.

Who bears the environmental and health risks? Low-income neighborhoods, communities of color, Indigenous nations, rural residents, and workers, who live near landfills, plants, and waste sites and face higher rates of illness with fewer resources to respond.

Who has a voice in decisions? Mostly corporations, regulators, and wealthier communities with lawyers and experts, while affected residents are often left uninformed, shut out of hearings, or ignored.

Use Katrina and Cancer Alley to connect burden, vulnerability, response and recovery, industrial development, and decision-making.

Katrina and Cancer Alley show how industrial development, vulnerability, and exclusion from decision-making reinforce each other. In Cancer Alley, corporations built facilities along the Mississippi River because the land was cheap, the area had low socioeconomic status, and the river was good for transport. Communities below the poverty line and communities with high Black populations overlap closely there, and these residents face high cancer risks from air pollution, with more than 50 chemicals in the air, including chloroprene, which causes irritation, irregular heart rate, and changes in the nervous and cardiovascular systems. This burden left residents more vulnerable when Katrina hit, since people with limited income and chronic health problems had fewer resources to evacuate, rebuild, or relocate, and recovery aid often followed existing inequalities while industry restarted quickly. In both cases, the communities bearing the greatest risks had the least say over siting, permitting, and rebuilding decisions, so the cycle of burden and neglect continued.

Distinguish hazard, exposure, and risk. Apply those terms to the chloroprene case.

Hazard: Can chloroprene cause harm? Yes. Chloroprene is toxic and can irritate the body, cause irregular heart rate, and change the nervous and cardiovascular systems. The EPA also classifies it as a likely human carcinogen.

Exposure: Are people coming into contact with it, and at what concentration? Yes. Chloroprene is released into the air from a plant along the Mississippi River, so nearby residents breathe it. Because they live next to the facility for years, their contact is long-term rather than occasional, and air monitoring near the plant has found concentrations well above the level the EPA considers safe for lifetime exposure.

Risk: Given the hazard and exposure, what is the likelihood of harm? High. A toxic, likely carcinogenic chemical combined with continuous, long-term exposure produces an elevated cancer risk and other health risks for residents. Since these communities are mostly low-income and Black, with few resources to relocate, the risk falls unevenly on the people with the least power over where plants are sited and how much they may emit.

Know why synthetic chemicals posed a different problem: novel chemicals, movement beyond use, persistence, difficult-to-control effects, and incomplete knowledge.

Synthetic chemicals pose a different problem because they are often novel, meaning living things and ecosystems have no evolutionary history with them and no natural way to break them down or respond to them. They also move well beyond where they are used: through air, water, soil, food chains, and consumer products, they travel far from factories and spread into places and bodies no one intended. Many persist for years or decades, as with PFOA and other "forever chemicals," so they build up in the environment and in human tissue instead of fading away. That makes their effects difficult to control, since once a chemical is released it cannot be recalled, and harms may appear slowly, at low doses, or only in combination with other chemicals. Finally, knowledge is incomplete: thousands of synthetic chemicals entered the market with little testing for long-term health or ecological effects, so regulators and communities often learn of the danger only after people have been exposed, which shifts the burden of proof onto those who are already harmed.

Know TSCA's purpose, the historical problem of roughly 60,000 existing chemicals, and the data, safety, and technology gaps.

TCSA: The law by which the United States regulates chemicals in commerce that are not foods, cosmetics, pesticides, or drugs. The law enables the U.S. EPA to compel industry to test for toxic or ecological effects of new chemicals that enter the marketplace.

When TSCA was passed in 1976, the chemical industry was invited to list all the substances that they had in production at that time. This list ended up having about 60,000 entries – this was the so-called TSCA Inventory. Testing of none of these chemicals could be required unless it was going to be used for new applications

Data gap: chemicals grandfathered in, allowing no further testing on them

Safety gap: government lacks tools to legally take action against harmful chemicals

Technology gap: government/industries have not invested in green chemistry

Explain how the 2016 TSCA amendments strengthened EPA's ability to evaluate existing chemicals and order safety data.

EPA cannot consider cost-benefits in evaluating safety. EPA can now order safety data on a specific chemical instead of going through slow rulemaking procedures. EPA is required to evaluate 20 existing high-risk chemicals within 3 years and to do other pro-active testing. EPA can collect fees from chemical manufacturers to do this work. EPA will encourage the development of non-vertebrate animal testing alternatives, which can include computational toxicology.

Define the precautionary principle: preventive action under uncertainty, burden of proof, alternatives, and public participation.

proving that something is safe. environmental measures must anticipate, prevent, and attack the causes of environmental degradation.

1) taking preventive action in the face of uncertainty;

2) shifting the burden of proof to the proponents of an activity;

3) exploring a wide range of alternatives to possibly harmful actions;

4) increasing public participation in decision making.

the absence of evidence of harm is not the same thing as evidence of the absence of harm.

Compare the general differences under REACH and historical TSCA

REACH, the EU's 2007 regulation, puts the burden on industry: under a "no data, no market" approach, manufacturers must register chemicals and supply safety data before selling them, and substances of very high concern can be restricted or require authorization. Historical TSCA worked the other way. Chemicals were presumed safe, about 62,000 existing ones were grandfathered in without required testing, new chemicals could be approved without health data, and the EPA had to prove "unreasonable risk" and choose the "least burdensome" regulation before it could act. Confidentiality claims also often hid chemical identities and data from the public. The result was that under TSCA, incomplete knowledge fell on the public, and communities were exposed to chemicals like PFOA before anyone had to show they were safe, while REACH tries to shift that burden to the producers who profit from the chemicals.

Trace water from source and watershed through treatment, distribution, household tap, wastewater, and the environment.

Water begins at a source, such as a river, lake, reservoir, or underground aquifer, and the watershed is the land area that drains into it, so anything released on that land, from farm runoff to industrial discharge, can end up in the supply. The water is then pulled into a treatment plant, where processes like screening, coagulation, sedimentation, filtration, and disinfection remove sediment, microbes, and some contaminants, though many synthetic chemicals, such as PFOA, are not removed by conventional treatment. Treated water enters the distribution system of pumps, storage tanks, and underground pipes, where aging infrastructure, leaks, and lead or other pipe materials can add contamination before it reaches the household tap. Once used for drinking, cooking, bathing, and cleaning, the water becomes wastewater and flows through sewers to a wastewater treatment plant, which removes solids, organic matter, and many pathogens but often not persistent chemicals or pharmaceuticals. The treated effluent, along with the leftover sludge, is then discharged into rivers, lakes, or oceans or applied to land, returning to the environment and often to another community's watershed, which closes the loop and starts the cycle again.

Explain why water safe at the treatment plant may not remain safe at the tap: aging infrastructure, corrosion, pressure changes, breaches, and intrusion.

Water that leaves the treatment plant meeting safety standards still has to travel through miles of pipes, tanks, and fittings before it reaches a household, and the distribution system can add contamination along the way. Aging infrastructure is a major factor: many cities rely on pipes that are a century old, which crack, leak, and break, creating openings for contaminants. Corrosion can release metals into the water, as in Flint, Michigan, where a change in water chemistry stripped the protective layer from old pipes and lead leached into homes, and lead service lines and plumbing fixtures can do the same at the household level. Pressure changes, caused by main breaks, pump failures, firefighting, or sudden shifts in demand, can cause backflow or create negative pressure that pulls outside material into the pipes. Breaches, such as cracks, loose joints, or failed seals, give contaminants a way in, and intrusion is the result: groundwater, sewage, soil, or bacteria seep through those openings into the pipe, especially when pressure drops. Meanwhile, low flow and long storage times in tanks and dead-end pipes let disinfectant levels fade, so bacteria such as Legionella can grow. The result is that "safe at the plant" does not guarantee "safe at the tap," and the burden of this gap often falls on older, lower-income neighborhoods whose infrastructure has received the least investment.

Distinguish SDWA from CWA.

SDWA: The Safe Drinking Water Act ensures that safe drinking water is in all U.S. public water systems. This does not count private wells.

CWA: The Clean Water Act is the primary federal law in the United States governing water pollution.

Distinguish enforceable primary standards from nonenforceable secondary aesthetic guidelines. An MCL is not a zero-risk threshold.

Primary standards are legally enforceable limits that protect public health, while secondary standards are nonenforceable guidelines for cosmetic effects (such as skin or tooth discoloration) and aesthetic effects (such as taste, odor, or color). Under the Safe Drinking Water Act, public water systems must meet primary standards, set as maximum contaminant levels (MCLs) for contaminants like lead, arsenic, nitrates, and bacteria, and violations trigger monitoring, reporting, corrective action, and public notification. The EPA only recommends secondary standards, so a system can exceed them without breaking the law, though problems like staining, bad taste, or odd color can still signal trouble and lead residents to distrust their tap water. An MCL is not a zero-risk threshold because it is set as close as feasible to the health-based goal (the MCLG), after weighing cost and available treatment technology. For carcinogens and other contaminants with no known safe level, the MCLG is often zero, yet the MCL is higher because zero is not achievable. Meeting an MCL therefore means a system is legally compliant, not that the water is risk-free, and vulnerable people such as infants, pregnant women, and those with weakened immune systems may still be harmed at or below the legal limit.

Distinguish elemental mercury, inorganic mercury, and methylmercury. Explain why form changes behavior and risk.

Mercury's chemical form determines how it moves and how the body absorbs it. Elemental mercury, the liquid in thermometers and dental amalgam, evaporates easily, so the main danger is inhaling its vapor, which reaches the brain and kidneys, while swallowing it is far less harmful. Inorganic mercury, found in mercury salts, dissolves in water and is absorbed mainly by ingestion or skin contact, mostly damaging the kidneys and digestive tract. Methylmercury forms when bacteria in water and sediment convert inorganic mercury into an organic form that is almost fully absorbed from the gut, crosses the placenta and blood-brain barrier, and builds up through the food chain in large predatory fish. It is the most dangerous for fetuses, young children, and communities that depend on fish for food, since it harms developing nervous systems.

Define bioaccumulation and biomagnification. Explain high seafood exposure despite lower water concentrations.

Bioaccumulation is the buildup of a substance in a single organism over time, when it takes in the substance (from water, food, or sediment) faster than it can break it down or excrete it. Biomagnification is the increase in concentration at each step up the food chain, as predators eat many contaminated prey and retain the substance. This explains high seafood exposure despite low water concentrations: methylmercury is present in water at tiny levels, but plankton absorb it and concentrate it, small fish eat large amounts of plankton, and larger fish eat many small fish, so each level multiplies the concentration. Because methylmercury binds to proteins in muscle and is excreted slowly, long-lived predators like swordfish, shark, and tuna can carry concentrations thousands to millions of times higher than the surrounding water. People who eat these fish, especially communities that rely on seafood as a staple, are exposed to the accumulated total rather than the low water level.

Trace Minamata: industrial release, conversion to methylmercury, seafood accumulation, dietary exposure, neurological harms.

the Chisso Corporation's chemical factory in Minamata, on Kyushu, Japan, dumped wastewater containing mercury into Minamata Bay, since mercury was used as a catalyst in making acetaldehyde. That industrial release put inorganic mercury into the bay's water and sediment, where bacteria converted it to methylmercury, and the factory's own process may have produced some methylmercury directly. Plankton took up the methylmercury, and it biomagnified through small fish, shellfish, and larger predatory fish, reaching concentrations far above those in the surrounding water. Because the town's residents, especially fishing families, ate fish and shellfish from the bay as a dietary staple, they were exposed to the accumulated total, and cats that ate the fish developed convulsions and died, which locals called "cat dancing disease." The methylmercury was absorbed almost fully from the gut, crossed the blood-brain barrier, and caused what became known as Minamata disease: numbness in the limbs, tremors, difficulty walking, narrowing of vision, hearing and speech problems, and in severe cases paralysis, coma, and death. Because it also crosses the placenta, mothers who seemed only mildly affected gave birth to children with severe congenital disabilities. The case was officially recognized in 1956, but the company and government were slow to act, and discharge continued until 1968, which ties the disaster to the justice themes of delayed response and the exclusion of affected communities from decision-making. The Minamata Convention was a global treaty to protect health against mercury.

Explain delayed action: uncertainty, economic dependence, corporate resistance, government reluctance, and unequal political power.

The discharge continued for years after the harm was evident because several forces reinforced one another. Scientific uncertainty gave everyone room to hesitate: researchers knew seafood was involved long before the exact toxic substance and mechanism were established, and linking the illness specifically to methylmercury from Chisso took time to prove. Economic dependence made that hesitation costly to resolve, since Chisso supplied jobs, tax revenue, and local political influence, so shutting down or restricting it threatened the whole town's livelihood. Chisso itself resisted, disputing the causal connection and withholding some damaging internal evidence, which kept the uncertainty alive. Government authorities, reluctant to impose major restrictions without what they considered definitive proof, deferred to that uncertainty and to the company's economic weight instead of acting on the accumulating evidence. Underlying all of this was unequal political power: the fishing families bore the exposure while the plant's benefits were far more broadly valued, so those harmed had little leverage to force a response. Together, the uncertainty was used as a reason to wait, the economic stakes raised the cost of acting, and the people paying the price had the least say, which is why the burden of proof effectively fell on the victims.

Know historical lead sources and children's vulnerability to neurological effects.

Historically, lead came from leaded gasoline (phased out starting in the 1970s and banned for on-road use in 1996), lead-based paint (banned for residential use in 1978), lead pipes and solder that corrode into drinking water, and industrial sources like smelters and battery plants, which contaminated air, soil, and dust. Children are especially vulnerable because their brains are still developing, so lead disrupts how neurons form and connect, and they absorb a larger share of ingested lead than adults. Their behavior also raises exposure, since they crawl, put hands and objects in their mouths, and eat dust and soil, and lead crosses the placenta, so fetuses are exposed too. The effects include lower IQ, learning and attention problems, and behavioral issues, and no safe blood lead level has been identified. Because old housing and contaminated soil are concentrated in low-income and minority neighborhoods, the burden falls unevenly.

Explain corrosion control and passivation, and why the source change without proper treatment caused lead leaching.

Old lead pipes and fittings are normally coated on the inside with a thin mineral layer of scale, a process called passivation, which acts as a barrier between the water and the metal. Water systems maintain this layer through corrosion control, usually by adding orthophosphate, which forms stable lead-phosphate compounds, and by keeping the water's pH and alkalinity in a range that doesn't dissolve the scale. In 2014, to save money, Flint switched its source from Detroit's treated Lake Huron water to the Flint River without adding corrosion control. The river water was more corrosive, with higher chloride levels and lower pH, and it was treated with more chlorine-based disinfectant. Without orthophosphate, the protective layer on the old pipes began to dissolve and was not replaced, so lead leached into the water and flowed to household taps. The change also let bacteria grow, and a Legionnaires' disease outbreak followed. Residents' complaints about discolored, foul-smelling water were dismissed for months before outside researchers and local pediatrician Dr. Mona Hanna-Attisha showed blood lead levels in children had risen, and the city did not return to Detroit's water until 2015.

Trace the Flint crisis from source switch and warning signs through independent water research, blood-lead evidence, and response

In April 2014, Flint, under state-appointed emergency management, switched from Detroit's treated water to the Flint River to save money, without adding corrosion control. Warning signs appeared quickly: residents reported discolored, foul-smelling water and rashes, bacterial contamination triggered boil-water advisories, and General Motors stopped using the water because it corroded engine parts, yet officials insisted the water was safe. Resident LeeAnne Walters and EPA official Miguel Del Toral raised alarms about missing corrosion control and high lead, and Virginia Tech researcher Marc Edwards and his team ran independent testing with residents that found far more lead than official numbers showed. Dr. Mona Hanna-Attisha then compared children's blood-lead records from before and after the switch and found a rise in elevated levels, which state officials first dismissed but the data confirmed. Under public pressure, Flint returned to Detroit's water in October 2015, followed by a state of emergency, pipe replacement, criminal charges, and a settlement. Residents and independent scientists, not regulators, exposed the problem.

Distinguish environmental monitoring from biomonitoring.

Environmental monitoring measures contaminants in the surroundings, such as air, water, soil, dust, or food, to show what is present and at what concentration. Biomonitoring measures the chemicals, or their breakdown products, in people's own bodies, usually in blood, urine, hair, or breast milk, to show how much was actually taken in.

Explain PFAS persistence using the carbon-fluorine bond; know their mobility and product functions such as water, oil, and stain resistance.

PFAS consists of 8 carbon chains with fluorine atoms which are one the strongest bonds in nature. This persistence makes them forever chemicals, as well as their ability to bioaccumulate and biomagnify and travel long distances. It has useful properties like oil resistance, stain resistance, and water repellant.

Know major pathways of PFAS including consumer products, food packaging, cosmetics, nonstick coatings, and aqueous film-forming foam.

Consumer products: Stain- and water-resistant treatments on carpets, upholstery, clothing, and outdoor gear contain PFAS. These products shed fibers and dust during use and release PFAS when washed or discarded, so exposure happens indoors through dust and in the environment through laundry water and landfills.

Food packaging: Grease-resistant coatings on fast-food wrappers, microwave popcorn bags, pizza boxes, and takeout containers can transfer PFAS into food, especially hot or oily food. Packaging that is thrown away also ends up in landfills and compost.

Cosmetics: PFAS are added to some foundations, mascaras, waterproof products, and long-wear formulas for smoothness and durability. They can be absorbed through the skin or ingested, and they wash down the drain.

Nonstick coatings: Cookware, bakeware, and some small appliances historically used PFAS-based coatings such as Teflon (made with PFOA). Scratched or overheated coatings can release particles, and manufacturing sites like the DuPont plant contaminated nearby water and workers.

Aqueous film-forming foam (AFFF): This firefighting foam, used at military bases, airports, and fire-training sites, contains PFAS and is sprayed directly onto the ground, where it soaks into soil and groundwater and contaminates nearby drinking water supplies. Firefighters are also exposed through the foam and their protective gear.

How these connect: Most pathways end up in the same places, namely drinking water, food, dust, and wastewater. Because PFAS don't break down, they accumulate in people's blood and in the environment, and conventional water treatment does not remove them.

Use the DuPont/PFOA case to explain how withheld evidence about toxicity, worker exposure, and water contamination can delay action

DuPont used PFOA at its Parkersburg, West Virginia plant to make Teflon, and its own studies showed the chemical was toxic, built up in workers' blood, and was linked to birth defects in children of some female employees. The company also found PFOA in local drinking water after dumping waste into unlined pits and the Ohio River. It shared none of this with regulators or residents, so farmers like Wilbur Tennant, whose cattle were dying, could not prove what was happening. Only when attorney Rob Bilott used litigation to force DuPont to hand over thousands of internal documents did the full record come out, which led to a large health study of residents, settlements, and the phase-out of PFOA. The delay shows that regulators cannot act on information they never see, communities cannot protect themselves, and the burden of proving harm falls on the people already exposed.

Define regrettable substitution. Shorter-chain alternatives may remain persistent, mobile, and difficult to remediate.

Regrettable substitution is replacing a hazardous chemical with an alternative that proves just as harmful because it was adopted before its safety was adequately studied. PFOA and PFOS were replaced with shorter-chain PFAS like GenX and PFBS, which were marketed as safer because they leave the body faster. But their carbon-fluorine bonds are just as strong, so they remain persistent. They are also more mobile, since they dissolve more easily in water and bind less to soil, spreading farther through groundwater and drinking water. They are harder to remediate because common methods like activated carbon capture them less efficiently, so filters need replacing more often and cleanup costs more. Faster clearance from the body also does not make them safe, since early studies still link some replacements to liver, kidney, and developmental effects.

Calculate a Hazard Index by summing concentration divided by each health-based value. Example: 5/10 + 5/10 = 1.0

The hazard index (HI) adds up how close you are to the safe limit for each chemical in a mixture, so you can see the combined effect instead of judging each chemical alone.

Step 1: Find the hazard quotient (HQ) for each chemical.
HQ = amount you're exposed to ÷ the safe level for that chemical

Step 2: Add the HQs together.
HI = HQ₁ + HQ₂ + HQ₃ + ...

"Concentration divided by health-based value" is the hazard quotient for one chemical: how much is in the water ÷ the level considered safe (the "health-based value"). That's my "exposure ÷ safe level."

"Summing" means adding those fractions together for every chemical in the mix.

The example, 5/10 + 5/10 = 1.0:

• Chemical 1 is at a concentration of 5, and its health-based value is 10. So 5/10 = 0.5, meaning it's at half its limit.

• Chemical 2 is also at 5, with a health-based value of 10, so it is also at half its limit (0.5).

• Add them: 0.5 + 0.5 = 1.0

Each chemical alone is only at 50% of its limit, but together they use up 100% of the combined "budget." A hazard index of 1.0 is right at the threshold of concern, and anything above 1 suggests the mixture may be a problem even though no single chemical exceeds its own limit.

Know the regulatory arc: nonenforceable advisories, the 2024 enforceable standards, and 2025-2026 proposed changes.

Nonenforceable advisories: For years, the EPA only issued health advisories for PFOA and PFOS (70 parts per trillion in 2016, later lowered). These were guidance that states and utilities could ignore, so no one was legally required to test for or remove PFAS.

2024 enforceable standards: The EPA set legally binding limits under the Safe Drinking Water Act. PFOA and PFOS were limited to 4 ppt each. PFHxS, PFNA, and GenX got their own limits, and a hazard index covers mixtures, meaning the combined concentration of these chemicals, each divided by its health-based value, cannot exceed 1.0. The original compliance deadline was 2029.

2025-2026 proposed changes: The EPA intends to keep the 4 ppt standards for PFOA and PFOS, but has proposed letting systems request up to two additional years, pushing compliance to 2031. It has proposed rescinding the rules for PFHxS, PFNA, GenX, and the hazard index mixtures. The stated reason is a procedural or legal issue under the Safe Drinking Water Act, and the agency says it may reconsider these chemicals through a future regulatory process.

Other federal programs: The picture is shifting here too. The RCRA corrective-action proposal was withdrawn, the RCRA hazardous-constituent proposal is still not final, TSCA reporting was delayed and proposed to be narrowed, and the CERCLA hazardous-substance designation was retained but with an emphasis on enforcement discretion. Meanwhile, states continue expanding their own PFAS regulation.

The takeaway: Enforceable limits arrived only after decades of advisories, and the protections are now partly delayed or uncertain. The mixtures and shorter-chain chemicals, the ones most tied to regrettable substitution, are the ones proposed for removal, so more of the gap may fall to the states and the communities exposed.

• Make a clear claim, support it with specific evidence or a course case, and explain why the evidence supports the claim.

• For environmental justice: identify the burden, benefits, decision-making power, and evidence needed to explain a disparity.

• For regulation: connect uncertainty and evidence generation to preventive action, responsibility, and safer alternatives.

• For a source-to-exposure pathway: identify prevention opportunities before, during, and after exposure occurs.