Toxic Substances

poison

A ____ is a type of toxicant that has a much narrower classification, it is a chemical that can cause illness or death at a very low dose of exposure

animal, humans

A buffer zone between the highest level of a chemical that produces no adverse effect in an ____ species and a level of exposure assumed to be safe for ____, Margins of safety are typically established through animal studies, but they are also analyzed through health risk assessment if there is a concern about human exposure

dioxin, eating

A chemical from an herbicide (Agent Orange) The most toxic type is TCDD It has never been intentionally manufactured A by-product in herbicide production Can escape into the atmosphere when it evaporates from soil or water, or when compounds are burned , Can be spread through precipitation Accumulates in fatty tissues, Most humans are exposed through ____ contaminated meat, fish, and dairy products

fertility, birth, development

Endocrine hormones regulate a wide spectrum of bodily functions including _____ and fetal development, can lead to ____ defects, impaired fertility, feminization of males Thyroid also important for brain maturation and _____ in fetuses/babies/children

unsafe, 18, monitor, reduce, report

Flint's water is still ____, In Michigan criminal charges have been filed against six government officials and two corporations (as of July 2016), It is not just Flint, ___ million Americans get their water from systems in violation of EPA lead rules (NRDC 2016) Violations include: Failure to _____ for lead, Failure to _____ lead levels, Failure to ____ test results to citizens

hazard, dose response, no observed effect level, exposure, risk

Health Risk Assessment (HRA) (1) ____ identification Based on testing for harm in animals (chapter 6) (2) ____-_____ assessment Based on tests of toxicity (just described) Establishes the ____-_____-______-____ (NOELs) If the substance is carcinogenic it is assumed to have no safe level of exposure 3) ______ assessment The number and types of people, duration, magnitude, geographic extent (4) _____ characterization Analysts take information from the first 3 steps and estimate the adverse health effects likely to occur in exposed population

2011, 2013

In 2009 the EPA embarked on a rule-making process that could require power plants (coal & oil burning) to reduce mercury emissions by 90% This rule was finalized in _____, Plants have 4 years to meet this rule U.S. has banned the export of elemental mercury (____), Effort to ensure reduction in mercury emissions in developing countries where emissions are not regulated, Protect imported seafood

mercury

Inorganic and organic _____ Most of it in the environment comes from coal combustion, mining and smelting of mercury-containing ores, and the incineration of its wastes (organic), in the atmosphere ends up in water sources, Humans are most likely to be exposed from eating tainted fish (especially marlin, tuna, shark and swordfish)

margins of safety

It is impossible to determine precisely where the threshold of tolerance is for any particular person But knowing there is a safe-level of exposure facilitates regulation by providing a basis for establishing _____ __ _____

blood, bones

Lead first moves into the _____stream Some makes its way into soft tissues such as brain and kidneys, About half is excreted quickly through feces and urine, Over time it is slowly deposited and stored in bones, It could then be rereleased back into the bloodstream because of high fever, osteoporosis, or pregnancy. Chronic exposure acute lead poisoning

learning

Lead mimics other minerals like zinc and iron, ones our bodies need to function properly cell death. It can also block neurotransmitters, prevents _____ Scientists on both sides, exposure was so vast it was difficult to determine what was "normal", private (industry) funding for science, coercion/bias, difficulty communicating science to Congress

1920, 1996

Lead started being added to gasoline in the U.S. in the _____s because it was found to improve engine performance, and it was inexpensive, From 1979-1986 the EPA established standards for a phase down of lead in gasoline, Lead was not completely banned until ____

70, 1956, economic

Libby, Montana, A small town (3,000 people) that was exposed to asbestos fibers from a local mine for over 70 years (1930-1990), Asbestos was recognized at the mine in 1956, state regulatory officials knew, mine owners knew, but workers were never told of the problem or given effective protective equipment, Smokestacks were emitting an estimated 5,000 tons of dust and fiber daily Workers and their families began to get sick by the 1960s, The plant closed for "_____ reasons" in 1990

asbestos

Likely candidate for the toxic substance that has caused the most death and disability , Found worldwide, primarily in Russia, China, Brazil, and in high-income countries

400,

More than _____ households registered water lead levels higher that 15ppb, 90 had higher than 100ppb, Estimated 9000 children under the age of 6 exposed

decades, bioaccumulation, biomagnification

PCBs: Once they enter the environment they persist for ____, Contamination of living organisms occurs, accumulating in fatty tissues such as liver, kidneys, heart, lungs, brain, and breast milk Continued exposure= _____ Can move up the food chain → _______ Tests have found detectable levels of PCBs in every animal from fish to birds to polar bears to animals living in deep sea trenches, A study in 1976 found PCBs in 99% of breast milk sampled, 25% had levels exceeding legal limits

toxicants

Substances that have the ability to cause harm to organs or biochemical processes away from the site on the body where exposure occurred, Different from other chemicals such as corrosives or irritants which only damage the tissues they contact

data, safety

TSCA enforcement issues :_____ gap: Producers are not required to investigate and disclose sufficient information on the hazard traits of chemicals to government, the public, or businesses that use chemicals. ______ gap: Government lacks the legal tools it needs to efficiently identify, prioritize, and take action to mitigate the potential health and environmental effects of hazardous chemicals.

dose, time

The amount of the chemical in question (___) and the duration of exposure (____) , this is the ___ and ___ relationship, dose is x axis, increasing effect is y axis

low, threshold, maximum

The data from these studies are plotted on a dose-response curve which has three parts: Far left indicates a range of ___ doses that produce no ill effects, The middle portion begins with the _____, where increasing dosage is beginning to provoke adverse symptoms, Flattens out after reaching _____ effect (death)

vary, individuals, dioxin, bad, workers

The health outcomes of acute vs. chronic exposure can ____, Thresholds of exposure are known for some substances and these are heavily regulated, but it is impossible to know what threshold exposures are for ________. Health consequences of chronic PCBs and _____ exposure are less clear. The health consequences of asbestos, lead, and mercury are quite clear - and they are ___. _____, pregnant women, and children are some of the most vulnerable groups

PCBs

The most widespread chemical contaminant throughout the global environment Primarily used in cooling liquids in electrical transformers and capacitors, but also in hydraulic fluids, adhesives, paints, sealants, and road coverings Restricted to use in industrial settings But they have escaped through the discharge of waste from factories into waterways, into airborne particulates that reenter ecosystems with precipitation, and from leaks, spills, and illegal dumping

100

This margin of safety standard is somewhat arbitrary, but it sets legal exposure limits that are well below the no-effect level, the sub-threshold amount divided by ____ = very small amount

toxic substances control act (TSCA)

Unlike pharmaceuticals and pesticides, industrial chemicals do not have to be tested before they go on the market, 83,000 chemicals registered with the EPA, As of 2015 only 250 have been tested by the EPA, Only 5 are banned: PCBs, chlorofluorocarbons, dioxin, asbestos, and hexavalent chromium

pregnant, 10, neurological

Warnings about mercury in fish are primarily targeted at ______ women, Fetuses exposed in utero are at increased risk of developmental delays and learning disorders, ___% of U.S. women of childbearing age have blood mercury levels high enough to put a baby at risk, 630,000 children born in U.S. each year at risk of ________ problems from mercury, For most people the health benefits of eating fish outweigh the risks of mercury exposure

chronic

___ toxicity: A chemical's ability to impair health when repeated low-dose exposure to the chemical occurs over a long time period

85, 40, 10

___% of all asbestos produced today is incorporated into cement construction materials Anything built before the 1980s in the U.S. might have it 20-__% of men worldwide report some degree of occupational contact with asbestos Until asbestos is eliminated, it is estimated that as many as __ million people may die of related cancer

acute, 50

____ toxicity tests: These studies are only done using lab animals, and the estimates for humans are inferred, or taken from cases of accidental poisonings, suicides, murders, or industrial accidents, Usually described by lethal dose LD50 , the amount of the chemical, administered in one dose, required to kill __% of a population of test animals in a 14 day period (mg of chemical per kg of body weight)

acute

____ toxicity: A chemical's ability to cause harm as a result of one-time exposure to a relatively large amount of the substance

lead

_____ exposure is the single most concerning environmental health problem for children in the U.S., It was recognized in the 1990s in the U.S. that 3-4 million children had blood levels high enough to impair brain functioning, Due to mobilized public health campaigns this number is declining, less than 500,000 children with levels above recommended threshold, The situation is improving, but the battle is far from over

chronic, 3, 1

_____ toxicity tests: run for the lifespan of the animal involved, all animals are killed at the end and autopsied, looking for carcinogenic effects which can take awhile to appear, Attempts to find a threshold exposure. Typically involves animal-feeding experiments with ___ test groups and ___ control group Group 1: A dose expected to have significant sub-lethal chronic effects Group 2: A dose expected to have no effect Group 3: A dose somewhere between 1 & 2

inhalation

asbestos exposure is primarily through ____ of tiny fibers suspended in the air, Fibers are deposited in the air passages and cells within the lungs, Most are quickly carried away by the mucus that lines the respiratory tract, throat, swallowed, excreted Some remain trapped deep in the lungs and may never be removed

lung cancer

asbestos related disease, About 5-7% of cases due to occupational exposure

asbestosis

asbestos related disease, Chronic disease characterized by scarring of the lung tissue Irreversible, excruciatingly painful, degenerative, and can lead to early death

mesothelioma

asbestos related disease, Rare cancer of the lung or stomach lining, Fatal, no effective treatment Asbestos is the only known cause

2013, 2015

case of flint michigan, ____ City of Flint decides to change water supply to the Flint River (cost savings), April 2014 Change goes into effect, residents immediately complain about look & taste, GM stops using river water in plant due to corrosiveness, report from VA Tech on lead in water, Jan 2015 City warns residents about high levels of disinfection byproducts (Cl), June 2015 EPA memo released on high lead levels in drinking water, city officials dismiss investigation, July 2015 MI DOH detects high blood lead levels in children but does not make link to water supply, Oct ____ Problem finally becomes public knowledge, City switches back to Detroit's water system

70, paints

current sources of lead: Over __% of lead in the U.S. comes from lead storage batteries (in most car batteries), Lead-based ____ used in old buildings and homes (used from 1884-1978): This is the primary cause of lead poisoning, Lead pipes or lead solder in old household plumbing, Imported food in lead-soldered cans

risk assessment

determining whether something suspected of presenting a human health threat is in fact dangerous, estimating how much injury or harm is likely to result from a given level of exposure, determining if those consequences are serious enough to warrant action

test, failed, public

government failures in flint michigan: Did not ___ the water for lead, ____ to treat the water with phosphates to reduce corrosiveness, Flint has water pipes made of lead that can leach lead into water if the pipes corrode, City and state antagonism toward EPA, EPA did not make findings _____, Argued that under the Safe Drinking Water Act it was MI's responsibility

low, dermal, FDA, EPA

health effects of PCBs: Lab studies have found toxicity at ____ concentrations in some animals , Exposure via dermal, respiratory, or oral routes Less risk via ____, More risk via respiratory or oral routes, Most common route is eating PCB contaminated fish, Some debate about higher concentrations in farmed salmon, Safe according to ___, Not safe according to ___

immune, high

health effects of dioxin: Chloracne, interference with _____ system function, reduced fertility, fetal loss, thyroid dysfunction, and cancer in humans Association between exposure and cancer come from Vietnam Vets; Seveso, Italy; exposed workers Rates are low but statistically significant Carcinogenic only at ____ levels of exposure The other type of levels most commonly encountered pose a minimal threat of cancer

nerve, continuum

health effects of lead: It interferes with blood cell formation, often resulting in anemia, Can cause kidney damage, sterility, miscarriage, and birth defects, It has a strong affinity for ____ tissue and can cause damage to central nervous system, Hyperirritability, poor memory, sluggishness, mental retardation, epileptic convulsions, coma and death at high levels, It exhibits a _____ of toxicity: Any amount of exposure carries some degree of harm

bioaccumulation, organic, high

health effects of mercury: _________ in fatty tissues, _____ mercury enters the bloodstream and binds to red blood cells, Can diffuse into the brain, destroying the cells that control coordination, Speech can become slurred, trouble walking, deafness, vision impairment, death, The most severe of these outcomes happen with acute or chronic mercury exposure at ____ levels

24, renovation, dust

lead paint: U.S. Department of Housing and Urban Development estimates that __ million dwellings nationwide are still lead contaminated, Deterioration or ______ may expose older layers The prime culprit is household ____ contaminated with lead from this paint

expensive

libby montana is very complicated to cleanup and very _____

400, 92, 20, 2008

libby montana, Over ____ residents of the area have died and 2,000 treated for asbestos disease (as of 2015), Of the men who worked at the mine for over 20 years, __% were diseased , When the EPA remediation team arrived in 2001, __% of residents tested had abnormal lung x-rays , Lawsuits started in the 1990s, but it wasn't until ____ when the company who had owned the mine agreed to pay $250 million for environmental clean up, $3 billion to compensate victims

liver, cancer

more health effects of PCBs: Most common outcome of exposure is chloracne, Some indication of links to diminished ____ function No link between PCB exposure and human ____ Persisting concern over their role as an endocrine disruptor, Research into human effects is still ongoing and inconclusive thus far

PELs (permissible exposure limits)

occupational exposure to lead has been regulated since 1978 through specified ____

duration, age, younger, long

risk factors for asbestos related diseases:Level and _____ of exposure, Dose-Time Effects, Time since exposure occurred, Disease takes time to develop _____ at which exposure occurred, _____ lungs more vulnerable, Personal history of cigarette smoking, Synergistic effects,Type and size of asbestos fibers ____ fibers are more injurious than short

oral, greater, respiratory

routes of lead exposure: ____ route, Ingested lead poses a much ______ hazard for young children than adults, They absorb lead into their bloodstream more easily, Children with micronutrient deficiencies absorb even more, Blood-brain barrier isn't complete until a child is 3 years old, lead can more readily move into central nervous system. ______ route, Lead dust or fumes can be inhaled

40

the legal status of asbestos: In the face of increasing evidence, over __ countries have full or partial bans, The U.S. and Canada are the two major holdouts among high-income countries, Canada (Russia china brazil india) is one of the largest exporters of asbestos, primarily to developing countries, and it continues to promote asbestos use and to oppose international efforts to outlaw the material, In the U.S. occupational exposure is regulated, and the government has banned its use in a number of consumer products and in home construction materials

toxicology

the study of toxic substances

chelation, reverse, prevention

treatment of lead: Children with high blood levels can be treated with _____, a process that employs a drug that binds to lead, facilitating its excretion Done in a hospital setting, 5-day treatment period Can be painful, Cannot ______ damage that has already been done, ______ is key, need to remove or encapsulate lead-based paint, prevent lead in drinking water

oral, respiratory, dermal

types of routes of exposure: ___:Through the mouth during eating, drinking, or smoking _______:Through lung inhalation _____: Through the skin