TEPC 6004 Exam 1 Questions and Answers: Environmental Toxicology, Exams of Social Sciences

Download TEPC 6004 Exam 1 Questions and Answers: Environmental Toxicology and more Exams Social Sciences in PDF only on Docsity! TEPC 6004 EXAM 1 QUESTIONS AND ANSWERS LD50 - Answers-lethal dose at which 50% die (dose is usually measured in mg/kg/day) TD50 - Answers-the toxic dose at which 50% of the individuals manifest with some kind of toxicity MTD - Answers-maximally tolerated dose NOAEL - Answers-no observed adverse effects level; highest dose that doesn't produce adverse effect LOAEL - Answers-lowest observed adverse effect level; lowest dose administered that does produce an adverse effect RfD - Answers-reference dose; value assumed to be safe for human population cancer risk - Answers-dose x slope factor Hazard Index - Answers-average daily dose/RfD, less then 1 you're okay, greater then one not okay. Slope factor - Answers-An upper bound, approximating a 95% confidence limit, on the increased cancer risk from lifetime exposure -the slope of the line found by plotting dose vs. cancer risk - a measure of the risk of susceptibility of developing cancer when oxposed to a carcinogen Explain how toxic agents are identified and characterized - differentiate between acute and chronic toxicity and tests for each - Answers-o Poison: Substance or mixture that can be life threatening. The end result is lethal. Knowing the dosage is important here o Toxicity: Measure of the inherent ability of a chemical to produce injury. The less of a substance it takes to cause injury, the more toxic it is. For example, one drop is more toxic than one quart Toxicity characterized by - Answers-• Time o Acute Toxicity: Sudden onset of toxic effect, minutes, hours, or days (e.g., irritants, chlorine gas); Acute does NOT mean severe o Chronic Toxicity: Toxic effect after long periods of exposure, usually many months or years (e.g., cancer, liver damage, lung fibrosis) • Location o Local Toxicity: Toxic effect occurs at the site of exposure (e.g., pulmonary edema, acid on skin, asbestosis) o Systemic Toxicity: Requires absorption of the toxicant into the body, then distribution of the toxicant (usually by the bloodstream) to susceptible organs, which is where the toxic effect occurs (e.g., liver damage, kidney damage) Absorption - Answers-o Absorption deals with how things enter into the body. Speaking specifically about undesirable environmental chemicals, ingestion is how the majority of chemicals will enter the body, followed by inhalation and then dermal contact The path through the gastrointestinal (GI) tract is unique. Things that are ingested and absorbed into the bloodstream go directly to the liver first—this is called the first-pass effect Distribution - Answers-o Distribution is where that chemical travels in the body Usually through the bloodstream Metabolism - Answers-is how the body, mainly the liver, breaks down the chemicals In the liver, there are many different kinds of enzymes to break down chemicals. The liver enzymes also break down chemicals in a way that typically prepares them for excretion through the kidneys. Liver enzymes also manage food so your body can use good things like sugars and proteins. In a way, the liver acts as sort of a sentry guard to manage chemicals that come in through this major portal of entry—the ingestion route Excretion - Answers-o We get rid of things in the body by excretion. Feces: food, chemicals, and indigestible materials can go through the GI tract and never be taken up into the body so they just pass right on through in the feces Expired air: a breathalyzer test measures the amount of alcohol on your exhaled breath. This accurately correlates to the amount of alcohol in your blood. So we eliminate some volatile chemicals (chemicals that easily go from a liquid to a gas/vapor state) through exhaled air Urine: this is the way most chemicals are excreted from the body. The body must get rid of things like ammonia created during normal functions, as well as environmental chemicals that inadvertently enter the body. Generally speaking, the liver prepares chemicals for excretion and the kidneys actually excrete. In a way, the liver and kidneys work as a team Characterize the primary routes of human exposure - Answers-o Dermal - exposure via the skin (workplace) o Oral - most common, through ingestion o Inhalation - breathing in (workplace) Risk - Answers-to expose to a chance of loss or undesirable outcome risk assessment - Answers-assess the nature and magnitude of the risk risk assessment steps - Answers-1. Hazard identification 2. Dose-response assessment 3. Exposure assessment 4. Risk characterization o Cons - possible meltdown, storage problems 3 ways water is used in a traditional nuclear plant - Answers-Extracting steam from fuel rods - water flows through fuel rods and becomes extremely hot Steam conversion - water is converted to steam and then back to water again, when water is turned to steam it expands rapidly, which turns the turbine blades (produces electricity) Coolant water - steam is cooled down and converted back to water again so cycle can continue Discuss limiting factors in alternative energy (e.g., water use, transmission, intermittency, etc.) - Answers-o Water - people use too much, corn used as biofuel requires a lot of water o Not a constant source o For wind, there has to be high gusts of wind for something to actually happen with it. It's very land intensive, each one needs about 100 acres of land between it o Solar is on a grid and cannot transmit energy to long periods of time o Geothermal uses electricity and water, hydro uses a lot of water Apply the energy issues discussed in class to the development of sustainable US energy policy - Answers-We have everything we need to combat climate change, what is missing is the willpower. By moving towards something like solar that is cheaper than coal, produces more jobs, and has zero emissions, we have the potential to solve the energy crisis and develop a sustainable US energy policy Describe each of the 6 criteria air pollutants to include how they are emitted, their human health effects and general corrective actions taken to mitigate the hazard - Answers-CO, NOx, SOx, PM 2.5/10, Pb, T. Ozone CO - Answers-inefficient combustion, binds with bloods hemoglobin reducing blood O2 carrying capacity, chemical asphyxiant NOx - Answers-acid rain, creates ground-level ozone, greenhouse gas which contributes to climate change SOx - Answers-acid rain (from coal), changes acidity of rivers and lakes which affects the fish tropospheric ozone - Answers-asthma, affects more Americans than the other five criteria pollutants combined, prematurely ages the lungs PM 2.5 and 10 - Answers-heart and lung disease, aggravated asthma 2.5 - smaller, deeper into lung (avioli) Lead (Pb) - Answers-neurotoxin, mostly solved with unleaded gas Understand the cause, controls and health implications of thinning Stratospheric Ozone - Answers-o Higher incidence of skin cancer o Stratospheric is best at filtering out UVC which does the most damage to our DNA o Excess ultraviolet reaching the planet can also negatively impact algae, plankton, plant life, and food sources. Describe how the Chesapeake Bay is impacted by air emissions - Answers-o Cars emit oxides of nitrogen and run into the bay, algae take the dissolved oxygen and creates dead zones o Over 20 million people live in the Chesapeake Bay watershed; cars emit oxides of nitrogen (NOx) that washes out from rainfall into the rivers and streams that lead to the Chesapeake Bay About 35% of the nitrogen pollution in the bay is from automobiles o After nitrogen enters the water, algae and bacteria start multiplying and as the algae and bacteria bloom, they consume the dissolved oxygen in the water, which suffocates the fish that breathe the dissolved oxygen through their gills This causes what is referred to as the "dead zone," which happens in most estuaries for the same reason but with the large population of lawn and farming activities, the dead zone in the Chesapeake Bay is quite large o Health effects include mycobacteriosis infections affecting more than half the striped bass and Vibrio (flesh eating bacteria) infection rates in human has doubled in 10 years Explain how mercury moves through the environment, its health effects and the story of Minamata, Japan - Answers-o When coal is burned, mercury is released to the atmosphere as a vapor. Rains wash this mercury into our rivers and streams. The mercury then bioaccumulates in fish. And as larger fish eat smaller fish, the mercury biomagnifies in the larger predator fish o Health effects - neurotoxin, effects nervous system leading to decreased IQ, language and memory, attention deficit disorders o Minamata - Chisso Corp. dumped mercury into sea between 1932-68 which bioaccumulated in fish; the excess amount in the fish caused blindness, hallucinations, inability to walk; nearly 2,000 people died; Chisso did not begin compensations until early 2000s and environmental cleanup until 2004 Explain the connection between energy, food and water withdrawal from the Ogallala Aquifer - Answers-o Ogallala Aquifer is the world's largest natural underground aquifer, but water supplies are running low o 94% is used for crop irrigation, gallons used for travel, water quality, climate change and biofuel production o Energy is used to withdraw water, spread over crops, and grow the food o Even if we move to biofuels, corn and other biofuels take a lot of water and energy to grow, which only exacerbates climate change Identify the current CO2 concentration and the pre-industrial CO2 concentration - Answers-Current - 400 ppm Pre- 280 ppm (never above 300) Short Wave affect on Greenhouse effect - Answers-o Short wave - (ultraviolet) contains lots of energy sun enters atmosphere as short-waves Once in the Earth's atmosphere, clouds and the surface absorb the solar energy Exposure to ultraviolet (UV) rays from the sun (shortwave radiation) leads to skin cancer Long Wave - Answers-o Long wave - (infrared light) contains less energy Ground heats up and re-emits energy as longwave radiation in the form of infrared rays. Greenhouse effect - Answers-o Greenhouse effect = The gases that make up our atmosphere let in the heat energy of the sun more easily than it lets out. When Earth puts out more infrared energy, the gases that make up our atmosphere block the infrared radiation from the Earth going out. So our atmosphere lets more energy in than it lets out Characterize the major greenhouse gases and their relative influence on climate - Answers-o CO2 - most concerned with, causes planet to heat, blocks outgoing radiation, lasts a very long time in the atmosphere o Methane (CH4) - component of natural gas, easily ignites, warms planet, also put out by cows, methane pockets o Nitrous oxides o Chlorofluorocarbon - CFC's arousal o Hydrofluorocarbon - HFC's AC, fridge o Sulfur Hexafluoride o Nitrogen Trifluoride Identify the temperature and CO2 concentration cap agreed to in Copenhagen 2010 and confirmed in the 2015 Paris Agreement - Answers-o <2 degree C temp rise (keep planet below 2 degree C) - some scientists argue it should be 1.5 degree C temp rise, point of no return (still warmup no matter if we stop with GHG emissions) o Zero emissions by 2050 (450 PPM) Discuss how public health is influenced by climate change - Answers-o Asthma/allergens o Spread of vector-borne diseases o Coastal flooding unsafe drinking water, contaminated water used for agriculture and animal raising, minor infections become much worse o Droughts dust bowl, women and children in developing countries have to walk farther for water o Sand storms respiratory diseases o More violent weather megastorms, more mental stress o Water/food shortage o Glacial retreat short latency, often reversible severity depends on dose uses uncertainty factors to account for differences (cross species, inter individual variability, others) more to the right on curve graph Cancer/Carcinogens approach - Answers-assumes no threshold, linear relationship at low doses long latency, irreversible auto-amplifying legions starts at (0,0) Cancer Risk - Answers-CSF x Exposure everyone's cancer risk is 33%, so added risk would make it 33+____ (whatever is calculated) Most used fossil fuel - Answers-Petroleum T/F: CO2 concentrations in the air are higher in the spring. - Answers-True Environmental risk using estimates of exposure and RfDs or slope factors - Answers- RfD: non-cancer, if dose <RfD then it is assumed to be safe MTD (max amount you can give someone without killing them) is used to determine CSF: fit curve to assume no threshold and linear response at low doses Gray area: 1 in 1 million(10e-6)=negligible risk but 1 in 10,000(10e-4) is too big of a risk Dose-response evaluation - Answers-asks: how much does it take to have an adverse effect? involves toxicology 2 primary approaches: 1. Non-cancer (uncertainty factor) 2. Cancer (probabilistic model) Probabilistic modeling (for carcinogens) - Answers-"To find the Cancer Slope Factor (CSF): - Model the data you have in the observed range - Assume a low-dose linear below observed data (where you transition from assumed/projected linear to observed range is called the point of departure) - Estimate the CSF from point of departure/projected linear assumption" Relationship between RfD, NOAEL, LOAEL - Answers-RfD < NOAEL < LOAEL