EESA10H3 Midterm: EESA10 Midterm Review

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Environmental Science
Silvija Stefanovic

EESA10 Midterm Exam Notes Week 1: Chapter 1: Environment: a complex system of living things and natural processes, the human species is one player in this web Hazards: chemical, biological, physical ● Chemical - industrial, pollutants, pesticides, lead in paint, cigarette smoke ● Biological - “biohazards” agents of infectious disease (mold, GMOs) ● Physical - contact with energy (radiation, noise, airborne dust particles, mechanical objects, extremes of heat and cold) Environmental health: More than industrial pollution, not based on genetic traits. Does not include an analysis of the effect of genetics on the likelihood of illness / injury from exposure to chemicals and hazards as a cause of disease Social / Behavioural Hazards: (drug use) not a part of environmental health. Environmental health does not consider the link between hazards and social behavioural elements Greater focus on anthropogenic hazards than naturally occurring hazards (floods, tsunamis, windstorms). Natural disasters can however create environmental health hazards - an example would be the ‘soup’ of industrial sewage wastes from Hurricane Katrina affecting health. “In an ecosystem nothing ever goes away” - Barry Commoner 21st century- our stuff and its byproducts remain in the environment. Western style development is not sustainable. There is also a large disparity between developed and less developed countries. TRANSCRIPT: “Everyday Carcinogens: Stopping Cancer Before It Starts” - Dr Sandra Steingraber There are 12 evidences linking cancer and the environment in Steingraber’s book “Living Downstream” - the article covers 4 Thesis: no one study gives absolute proof of a link between cancer and the environment. All the studies fit together like a puzzle, the make sense together. 1. Cancer Registries: measure of cancer incidences in a population ● Canada and the U.S are very similar ● Non tobacco related cancers are rising in incidence among all age groups - this is since the early 70s dating back to WWI ● This is not caused by lifestyle / hereditary factors / it’s partly because of lack of early screening but mostly not ● Childhood cancers have doubled since 1959. 10% rise in 10 years ● Rise in testicular cancer in men 19-45 / tripled since WWI ● Non Hodgkins Lymphoma has doubled over 4 decades. Multiple Myeloma also doubled in 40 years ● Brain cancers growing in children, 54% up in 2 decades ● All these rises have not been caused by lifestyle, diet, exercise, more early screening, or heredity, which would indicate maybe the environment is at play. 2. Computer Mapping - cancer registry data displayed over space instead of time ● Cancer is not random ● Ex- Great Lake Basin / Eastern Seaboard Great Lakes Region - breast / colon/ bladder cancer high in these regions that are highly industrialized ● There is a correlation between environment and cancer ● Highly industrialized = greater cancer - this may not be causation though ● Non Hodgkins Lymphoma is high in the Great Plains, Kansas, Nebraska, Iowa, Illinois, Wisconsin where there is high pesticide use 3. Our Own Bodies - humans have several chemicals in their bodies from exposure ● Pesticides, industrial solvents, PCBs, dioxins… ● Common in Hamilton ● Chemicals go to breast milk, fat, blood, semen, hair, umbilical cords, fluid surrounding human eggs. ● Chemicals linked to cancer in bodies ● New Development: need to assess endocrine disruptors that interfere with hormones in addition to chemicals causing mutations ● Hormones are messengers directing genes ● Chemicals mimicking hormones don’t damage genes they disrupt the message. They are trespassers that send a message not meant to be sent ● These chemicals work with elements already in the body. They may cause faster development of cancer ● Timing of Exposure: an old thinking was “the dose makes the poison” meaning one could regulate carcinogens to a low level that is not harmful ● New Science: each person has windows of vulnerability when they are especially sensitive to chemicals. The prenatal period - exposure in the womb intensifies exposure later on in life. Adolescence - girls breasts must be shielded when getting an Xray as this intensifies risk of cancer 4. Animals - parallel between cancer in animals and in humans ● Animals in pristine regions don’t develop certain cancers ● Ex: Beluga whales in the St Lawrence river have high cancer rates because the river is less clean ● Non Hodgkins is high where there is high use of pesticides ● Farmers have high raters of it, Vietnam veterans exposed to Agent Orange (a weed killer) have it ● Dogs whose owners use lawn chemicals are more prone to get cancer ● Hodgkins- chromosome breaks, flips and reattaches itself - pesticide applicators have this mutation ● Dioxin- break milk heavily contaminated by it,foods from animal flesh second most contaminated ● Dioxin is a byproduct of burning plastic - big issue in Hamilton ● Dioxin (in the air) goes into body through consumption and accumulates over time ● Animals feed on plants with particles and dioxin enters the food chain ● The contaminants in a woman’s body find their way into the next generation through breast milk ● Animals are better to study because they don’t have lifestyle factors causing cancer ● Burden of proof in science is 95% - in 1964 a surgeon announced smoking as cancer causing without much proof. Steingraber argues there should be an effort to fight for uncontaminated breast milk though scientific proof isn't at the 95% mark Week 2: Lecture 2 Air ● london smog(1952) ○ smoke and sulphur dioxide pollution killed many ● airborne hazards (outdoor and indoor) ● sources (outdoor) air pollution: ○ human sources ■ stationary (factories) ■ mobile (cars) ○ natural sources ■ volcano eruption ○ burning fossil fuels ■ for electricity ■ releases CO2 into the air and many other pollutants ● health effects (outdoor) air pollution ○ asthma ■ particles (SO2) irritate bronchial passages leading to severe difficulty in breathing ○ chronic bronchitis ■ excessive mucus produced in cough causing lasting cough ■ from SO2 and smog ○ Pulmonary emphysema: weakening of alveoli wall ■ shortness of breath (NO2 involved) ○ can also cause lung cancer and heart disease ● Common air pollutants: ○ particulate matter, CO, Nitrogen Oxide, Sulphur dioxide, volatile organic compounds (VOC), lead, ground level ozone ● Particulate matter ○ particles found in air (dust, smoke) ○ from vehicles and factories ○ serious health effects ● CO (carbon monoxide) ○ incomplete burning of fuels containing carbon ■ ex: heaters, stoves, fireplace ○ mainly a problem for indoor air pollution ○ health impacts: ■ interferes with oxygen delivery ■ fatigue headache nausea ● Nitrogen Oxide ○ forms in any time of combustion process ○ formation of ground level ozone ○ acid rain formation ● Sulphur Oxide ○ burning of coal and oil ○ dissolves into water and makes it acidic ○ causes respiratory illness—> increases chance of heart and lung disease ● VOC ○ made of many organic compounds ○ hydrocarbons: methane, butane and propane ○ photochemical smog ● Lead ○ vehicles and industrial sources ○ deposit in soil and water ○ affects mainly young children (dirt etc) ○ neurotoxicant ■ lowers IQ and neurological performance ■ cardiovascular mortality ○ Ozone ■ VOC +NOx + heat + sunlight = ozone ■ good in stratosphere but bad in ground level ■ causes lung damage (shortness of breath) ○ Indoor air pollution ■ 5X more concentrated than pollutants in the other air ■ buildings are airtight with less ventilation ○ Sources: ■ building materials, furniture ■ cleaning products ■ pesticides, cooking ■ “Sick building syndrome”: ■ same symptoms experienced by occupants of a buildings ○ health effects (indoor air pollution) ■ takes years to develop ■ asthma, cancer ■ headaches ● Asbestosis ○ fibrous minerals used in buildings, car breaks, and heat resistant fabrics ○ doesn't evaporate into air or dissolve in water ○ cant move through soil ○ doesn't break down ● Health ○ impacts lungs and membrane that surrounds the lungs ○ asbestosis—> scar like tissue(causes difficulty in breathing) ○ plaques in neural membranes ○ lung cancer, mesothelioma ○ increased risk of other cancers ● Formaldehyde ○ VOC, naturally occurring gases ○ gas at normal room temperature ○ released by burning wood, cars, glue in pressed wood or paints ○ allergic reactions ■ skin rash, burning eyes, throat ○ nausea, cancer, coughing ● Mold and moisture ○ needs moisture to form, not standing water ■ bathroom, kitchen, gym area, locker room, damp basement ○ triggers asthma by toxins and irritants, indoor allergens ○ control moisture to stop this ○ can produce tiny spores, odour, discolouration ● Second hand smoke ○ non smoker exposed has 25% more chance of lung cancer ■ many die from exposure ○ adults can get heart disease/attack, lung cancer ○ children usually get asthma and pneumonia ○ Lec. 2- Chapter 4 (pg. 128-136) ENVIRONMENTAL IMPACTS OF BURNING FOSSIL FUELS (PG. 128 -136) - Most combustion products from burning fossil fuels are released into the atmosphere becoming air pollution, a term that has traditionally referred to pollution of the troposphere. About Combustion: - Basic definition: combustion is a chemical reaction that requires a hydrocarbon fuel, the presence of oxygen, and an initial source of heat. - Heating causes the hydrocarbon fuel to break down & recombine with the oxygen, forming water and carbon dioxide. This oxidation reaction also releases heat energy, causing combustion to continue as long as fuel remains. - The extra heat energy, beyond that needed to maintain the combustion, can be put to use for human purposes. When not enough oxygen is immediately present for a hydrocarbon fuel to burn completely, carbon monoxide is formed instead of carbon dioxide. - Combustion under real-world conditions is often incomplete, and fossil fuels are more than just hydrocarbons. Further, some air pollutants from the burning of fossil fuels set in motion complex secondary impacts. - Most of the water used in power production is not consumed, but is returned to the body of water from which it was originally taken - Even after cooling, this water is still warmer than the receiving body of water, an effect referred to as thermal pollution Basic Products of Combustion: Oxides and Particulates - We burn fossil fuels to power vehicles of all types, to generate electricity, and to heat commercial and residential buildings - Some heavy manufacturing facilities, including petroleum refineries, metal smelters, and pulp and paper mills, are powered directly by burning fossil fuels - Because combustion is oxidation, the combustion of fossil fuels produces several oxides - Carbon dioxide (CO2), a natural constituent of the atmosphere, is released anytime fossil fuels are burned - Carbon monoxide (CO) is mainly a product of inefficient burning when vehicles idle - Nitrogen is plentiful in the atmosphere, and thus oxides of nitrogen—the gases nitrous oxide (N2O), nitrogen dioxide (NO2), and, if combustion is incomplete, nitric oxide (NO)—are produced by burning - Cars and power plants are the major sources of these pollutants - Nitrogen dioxide is a brownish gas that is a visible marker of air pollution - In the field of air pollution, NO2 and NO are together referred to as NOx, pronounced “nox” - Sulfur is present in most cool and crude oil - Sulfur dioxide (SO2) gas is produced mainly when coal or sulfur containing oil fuel is burned - Sulfur Oxide (SO) may also formed, but does not persist as a stable compound - SO and SO2 are together known as Sox - Because sulfur is refined out of gasoline and heating fuels, cars and furnaces did not produce Sox - Because sulfur is refined out of gasoline and heating fuels, cars and furnaces did not produce Sox In the atmosphere, some sulfur dioxide is converted to tiny water soluble particles known as sulfates The burning of fossil fuels adds to the burden of particles in the air - Particulate Matter (PM)/ Particulates: the complex mixture that may consist of both small solid particles and fine liquid droplets, and may include solid particles (dust), sulfate, metals, and organic chemicals; long, narrow fibers, such as asbestos fibers, are considered elongated mineral particles - A common organic component of particulates is a group of compounds known as polycyclic aromatic hydrocarbons (PAHs) - Polycyclic aromatic hydrocarbons (PAHs) A group of related organic compounds that are products of incomplete combustion and are ubiquitous in the environment Other Pollutants Liberated by Combustion: Mercury, Lead, VOCs - The burning of fossil fuels releases other substances as well o Mercury: A neurotoxic heavy metal that is liquid at room temperature § Elemental mercury vapor rises and moves into the atmosphere § The quantity released for ton of coal burned is small, but we burn many tons of coal, and mercury is strongly neurotoxic - In the atmosphere, elemental mercury can be carried with air currents for some time, but eventually it settles out or is deposited with rain or snow - Certain species of bacteria convert the mercury from its elemental form to a different form called methylmercury o Methylmercury becomes concentrated in the muscle of fish - Like mercury, lead has long been known to be neurotoxic at high doses - Lead: A neurotoxic heavy metal o Lead was deliberately added to gasoline to improve engine performance - When leaded gasoline is in use, lead is a widespread in airborne particulate matter, which is gradually deposited on the ground through settling or with precipitation - Exposure to lead in soil or dust, mostly by incidental ingestion, have continued long after leaded gasoline was banned - Burden of lead in soil is especially heavy in urban areas - Oil contains some naturally occurring volatile organic compounds (VOCs) - Volatile Organic Compounds (VOCs): A naturally occurring or man-made organic compound that volatilizes significantly at ordinary environmental temperatures - VOCs are sometimes added to gasoline to improve its performance - Some VOCs are released whenever oil or gas is burned Secondary Pollutants Formed in the Atmosphere: Ozone, Nitric Acid, Sulfuric Acid - Some pollutants are chemically transformed in the environment producing secondary pollutants - Secondary Pollutants A pollutant formed in the environment through the chemical transformation of the original pollutant Photochemical smog is created through a complex series of chemical reactions among NOx, VOCs and other chemicals in the presence of sunlight - Photochemical Smog: smog created through a complex series of chemical reactions among nitrogen oxides, volatile organic compounds, and other chemicals in the presence of sunlight - This brand of smog is a particular problem in warm, sunny, and densely urban locales such as Manila, Jakarta, Mexico City, and Southern California - Ozone: the triatomic form of oxygen o A key component of photochemical smog o An important secondary pollutant - The naturally occurring layer of ozone in the stratosphere is valued for the protection it provides against ultraviolet radiation o The ozone formed at ground level as a result of pollution is a health hazard - Smog: A contraction of smoke and fog, visible air pollution; or photochemical smog specifically - Secondary pollutants are then deposited in precipitation—an outcome originally dubbed acid rain and now known more formally as acid deposition - Acid Deposition (Acid Rain): precipitation made acidic by the atmospheric conversion of nitric oxide and nitrogen dioxide to nitrates and nitric acid, and of sulfur dioxide to sulfates and sulfuric acid - Acid deposition acidify soil and can severely damage the leaves of trees - In some lakes and streams, fish species that cannot tolerate acidic waters have been completely eliminated Local and Regional Health Impacts of Burning Fossil Fuels Particulates and Pollutant Gases Fate of Particulates and Pollutant Gases in the Respiratory System - Nose and throat, trachea, bronchi, bronchioles—form a transport system for moving air in and out of the lungs - Gas exchange, the real business of breathing, takes place deeper in the lungs - Particulates and pollutant gases enter the respiratory system with each inhaled breath - Once a particle lodges on an internal surface, it is not readily exhaled, but rather must be removed by some physiological mechanism - PM :10articulate matter 10 microns or less in diameter - PM :.5articulate matter 2.5 microns or less in diameter - Particulates 10 microns or less in diameter are considered respirable particulates - Respirable Particulates: generally, particulates 10 µm or less in diameter - Particulates from 2.5 to 10 µm come mainly from natural or mechanical sources (plowing, grinding, abrasion) - Fine particulates come mostly from combustion - Ultrafine particulates: those 0.1 microns or less in diameter o Most common source is diesel engines Smaller particles stay airborne longer and penetrate deeper before settling out The smaller the particle, the more it behaves like a gas, whether in the airways or in the ambient environment - Some course particles are filtered out by fine hair lining the nasal passage o These particles may be expelled by sneezing or blowing the nose, or they may be swallowed - Particulates 2.5 to 10 µm in diameter settle out in the trachea and bronchi, which are lined with cilia - Find particulates can reach the small airways and the alveoli - It has become clear the ultrafine particulates can pass through the alveolar wall into the bloodstream and circulate throughout the body - Both ozone and it’s precursor, nitrogen dioxide, penetrate the lower respiratory tract, as does sulfur dioxide if it is adsorbed to particles or aerosols - Carbon monoxide crosses the alveolar boundary into the blood, entering the general circulation Physiological Effects of Particulates and Pollutant Gases - The organ systems most affected are the respiratory s ystem in the cardiovascular system - Particulate matter of the major pollutant gases from the burning of fossil fuels have direct irritating effects in the respiratory passages - Particulate matter and ozone damage the cells that line the respiratory tract - Ozone most strongly affect the cells that have cilia - Particulates and ozone cause local inflammation - Chronic inflammation of the bronchial is a feature of asthma, and asthmatics are more susceptible to this effect of air pollutants o Sulfur dioxide causes bronchoconstriction, which pampers airflow and leads to respiratory distress o Find particulates and nitrogen dioxide can impair the functioning of the immune system’s scavenger cells in the alveoli - Carbon monoxide, after crossing into the bloodstream in the lungs, binds to hemoglobin in the blood o By denying oxygen to the brain, carbon monoxide causes a loss of alertness and, at high doses, unconsciousness and death 5.4 Physical Hazards in the workplace (pg 211-213) - There are several physical hazards that affect people outside the occupational setting: o Airborne fibers and dusts o Mechanical hazards that cause physical injury o Excessive noise, causing hearing loss and other health effects o Exposure to light during nighttime hours - Fibers and Dusts o Particulate comprises of irregularly shaped particles and dusts o Fibrosis means scarring of the lungs in response to a physical irritant, with the formation of excessive fibrous tissue and a loss of flexibility that impairs breathing. o Workers sustained the highest exposures to particles and fibers o Similar to silica dust and coal dust, asbestos fibers and cotton dust are respiratory hazards to workers. - Asbestos Fibers and Synthetic Substitutes o Asbestos is a type of mineral fiber that is insulating, durable, and non- combustible. o Asbestos are used in building insulation and brake linings o There are 3 major types of asbestos § Chrysotile §
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