Understanding Pollution and its Impacts: A Comprehensive Overview
This comprehensive guide delves into the vocabulary of pollution, toxicology, and exposure levels to toxic chemicals. It explains the different measurements for expressing contaminant levels in food and water, major types of air pollutants, primary and secondary pollutants, and the formation of photochemical smog. Essential concepts such as risk, hazard, toxicity, dose, and response are explored, providing a deep insight into the world of environmental pollution.
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APES POLLUTION NOTES
POLLUTION VOCABULARY Risk a measure of the likelihood that you will suffer harm from a hazard. Hazard Something that can cause injury, disease, economic loss, or environmental damage. Toxicology Study of adverse effects of chemicals on health. Toxicity Measures how harmful a substance is in causing injury, illness, or death to a living organism. Dose - is the amount of a substance a person has ingested, inhaled, or absorbed through the skin. Response the type and amount of health damage that result from exposure to a chemical or other agent. Poison or toxin is a chemical that adversely affects the health of a living organisms causing injury, illness, or death.
How Much Exposure to a Particular Toxic Chemical Causes a Harmful Response? 50 % Method: Measure chemical s median lethal dose (LD50); the amount received in one dose that kills 50% of the organisms (usually rats or mice) in a test population within a 14 day period. Threshold Level 0.0001 0.001 0.1 1.0 Dose mg/kg (ppm)
Measurements for Expressing Levels of Contaminants in Food and Water For Acute Toxicity Tests Dose Metric Equivelent Approximate Amount of Water Parts per million (ppm) Milligrams per kilogram (mg/kg) 1 teaspoon per 1000 gallons Parts per billion (ppb) Micrograms per kilogram ( g/kg) 1 teaspoon per 1,000,000 gallons
Major Types of AIR Pollutants Air Pollution is the presence of one or more chemicals in the atmosphere in quantities and duration that cause harm to humans, other forms of life, and materials. Primary Pollutants chemicals released into the atmosphere that mix both vertically and horizontally and are dispersed and diluted in the troposphere. Secondary Pollutants primary pollutants that react with other basic component of air to form new pollutants.
Photochemical Smog (Brown Smog) Photochemical smog is a mixture of primary and secondary pollutants formed under the influence of sunlight. Primary Pollutants involved are mostly NOx and volatile hydrocarbons + sunlight to produce ozone (O3), aldehydes (CH2O), PANS (peroxyacyl nitrates), and nitric acid (HNO3).
Chemical Reactions Form Chemical Oxidants N2 + O2 2NO 2NO + O2 2NO2 (yellowish brown gas with a choking odor) Some of the NO2 reacts with water vapor to produce nitric acid and nitric oxide which ultimately forms ozone. 3NO2 + H2O 2HNO3 + NO NO2 + uv radiation NO + O O2 + O O3 Hydrocarbons + O2 + NO2PANS
Industrial Smog (gray smog) Industrial smog consists mostly of sulfur dioxide, suspended droplets of sulfuric acid, and a variety of suspended solid particles and droplets that emanate from coal and heavy oil burning power plants and factories.
Industrial Smog Chemistry When coal and oil are burned: C + O2 CO2 and/or 2C +O2 2CO The sulfur compounds in coal and oil react with oxygen to produce sulfur dioxide, a colorless, suffocating gas. S + O2 SO2 In the troposphere, some of the sulfur dioxide reacts with oxygen to form sulfur trioxide which then reacts with water vapor to produce tiny suspended droplets of sulfuric acid. 2SO2 + O2 2SO3 SO3 + H2O H2SO4 Some of the sulfuric acid droplets react with ammonia in the atmosphere to form solid particles of ammonium sulfate (salt). These salts + soot give the characteristic gray color to this smog. 2NH3 + H2SO4 (NH4)2SO4
Factors That Influence The Formation of Smog Local climate Topography Amount of industry Fuels used in industry, heating & transportation Amount of precipitation (rain and snow cleanse atmosphere of pollutants) Wind patterns (winds sweep pollutants away) Hills and mountains reduce flow of air in valleys and allow pollutants to accumulate at ground level. Diurnal temperature fluctuations allow pollutants to move upward and downward in atmosphere (density differences) to prevent pollutants from accumulating at ground level.
Thermal Inversions Warm air normally rises in the atmosphere. In a valley, a layer of dense, cool air, can become trapped below a layer of warm air capped by a denser cool air layer. This prevents air from ascending keeping air pollutants trapped in the lowest cool air layer. These events typically only occur for a few hours. When high pressure air masses stall over valley areas, thermal inversions can last for several days. Las Angeles California is surrounded by mountains on three sides with over 15 million people, over 24 million motor vehicles and is subject to thermal inversions 50% of the year! LA = has the worst air pollution in the USA
Other Highly Polluted Cities in the World Mexico City Denver, Colorado Mexico City, Mexico Rio de Janeiro and Sao Paulo, Brazil Beijing and Shenyang, China Bangkok, Thailand Beijing,China
Effects of Air Pollutants on Health Sulfur dioxide causes constriction of the airways and causes severe constriction for people with asthma. (WHO estimates 625 million people exposed from burning fossil fuels). Nitrogen Oxides especially NO2 can irritate the lungs, aggravate asthma and chronic bronchitis, cause emphysema-like conditions, and increase susceptibility to respiratory infections. NO2 has recently been attributed to the cause of malignant melanoma. VOC s (benzenes and formaldehyde) and toxic particulates such as lead, cadmium, PCB s and dioxins (agent orange) can cause mutations, reproductive problems, and cancer. Ozone causes coughing, chest pain, shortness of breath, and eye, nose, and throat irritation. Ozone alert days - Has nothing to do with UV index!
Solutions: Preventing and Reducing Air Pollutants Clean Air Acts of 1970, 1977, and 1990 These laws require the EPA to establish national ambient air quality standards (NAAQS) for seven outdoor pollutants: Suspended particulate matter Sulfur oxides (SOx) Carbon monoxide (CO) Nitrogen oxides (NOx) Ozone (O3) Volatile Organic Compounds (VOC s) Lead (Pb) 1. 2. 3. 4. 5. 6. 7.
How Can US Air Pollution Laws Be Improved? 1. Pollution prevention is best! Leaded gasoline outlawed, lead in air was reduced by 98%. 2. Increase fuel efficiency standards for cars and trucks, this will reduce oil imports. 3. Require stricter emission standards. 4. Fund research and development of alternative energy resources. Subsidize businesses and homeowners, vehicle owners for using energy conservation approaches such as hybrid vehicles, solar and wind energy for space heating, green buildings, etc..
SEDIMENT POLLUTION Sediment Kills Reefs Sediment releases into surface waters due to poor land management decreases water clarity, increases turbidity, buries organisms, decreases the availability of light for photosynthesizing organisms, and brings insoluble toxic pollutants including PCB s and DDT. 1.3 million pounds of PCB s in Hudson River from GE Plant. Must dredge 2.6 million yards! Long residence time in environment. DDT banned in the USA for application BUT we are the #1 producers of DDT for sales worldwide! Long residence time in environment. DDT (50years), DDE (200 years).
INORGANIC CHEMICALS (water-soluble nutrients) Heavy metals such as mercury (Hg) and lead (Pb) from industry, mines, irrigation runoff, oil drilling, and urban runoff from storm sewers. (point source and non- point source pollution) Lead (Pb) additives in gasoline (MTBE s) contaminate the air. Lead gas banned in the USA (still available in other parts of the world). It is also present in incinerator ash. This is classified as hazardous waste and must be disposed of in a special landfill. It leaches into groundwater. Residues can also be found on food resources located downwind from incinerators. Lead paints banned in USA, but can still be found in buildings. Greatest risk for Pb poisoning are mid-aged men (high blood pressure), pregnant woman (miscarriage, premature births and stillbirths), and young children (mental/physical impairments hearing loss, hyperactivity, ADD, low IQ, LD).
INORGANIC CHEMICALS (water-soluble nutrients) Mercury (Hg) mostly from industrial processes (wastewater), also from batteries, paints and plastics burned in incinerators. Burning converts it to methyl mercury which readily enters food webs. Bioaccumulation in muscle of tuna, shark, and swordfish. Biomagnification since they are top predators. Long residence time in environment toxic to humans and causes mental retardation in children and kidney failure.
BIOACCUMULATION AND BIOMAGNIFICATION Biomagnification
Nitrogen and phosphorous loading (cultural eutrophication causes and increase in algae (bloom) which causes a decrease in DO resulting in the death of aquatic organisms. Decomposing aerobic bacteria continue using DO (increase in BOD) in water until the conditions become Anoxic!
SEPTIC TANKS Septic tanks are used in areas where there are no combined sewers. Septic tanks (cesspools) must be emptied each year. Old tanks can crack and leak coliform bacteria into surrounding soil, groundwater, and surface waters.
SEWAGE TREATMENT Sewage treatment means removing impurities so that the remaining waste water can be safely returned to the surface waters (river, bay, ocean) and become part of the natural water cycle again. sewage treatment separates solids from liquids by physical processes and purifies the liquid by biological and chemical processes
PRIMARY TREATMENT solids are separated from the liquid by passing the sewage through large settlement tanks, where most of the solid material sinks to the bottom. About 70% of solids settle out at this stage and are referred to as sludge. The sludge is used on farms after further treatment called sludge treatment.
SECONDARY TREATMENT a biological process which relies on naturally occurring microorganisms acting to break down organic material and purify the liquid. The rate of this process can be increased by pumping air into tanks of sewage where the aerobic digesters float freely and feed on the bacteria. These treatment units are called aeration tanks. Following either form of secondary treatment, the waste water is settled in tanks to separate the biological sludge from the purified waste water.
Primary Secondary Grit chamber Chlorine disinfection tank Bar screen Settling tank Aeration tank Settling tank To river, lake, or ocean Raw sewage from sewers (kills bacteria) Sludge Activated sludge Air pump Sludge digester Sludge drying bed Disposed of in landfill or ocean or applied to cropland, pasture, or rangeland (Sludge cake or pellets)
WAYS TO REDUCE CULTURAL EUTROPHICATION Advanced waste treatment (sewage and industrial) Regulate detergents cleaning products for phosphates. They have been regulated since the 1970 s on Long Island! Promote soil conservation and preservation of wetlands to capture and filter pollutants before they enter surface waters. Regulate fertilizer, pesticide, agricultural and livestock runoff to control Nitrogen, phosphate, and PAH s. Create policies and economic incentives for doing these things!
EXXON VALDEZ OIL SPIILL On March 24, 1989, shortly after midnight, the oil tanker Exxon Valdez struck Bligh Reef in Prince William Sound, Alaska, spilling more than 11 million gallons of crude oil. The spill was the largest in U.S. history. Capt. Joe Hazelwood, who later admitted to having had several alcoholic drinks that day. The spill posed threats to the delicate food chain that supports Prince William Sound's commercial fishing industry. Also in danger were ten million migratory shore birds and waterfowl, hundreds of sea otters, dozens of other species, such as harbor porpoises and sea lions, and several varieties of whales. In the aftermath of the Exxon Valdez incident, Congress passed the Oil Pollution Act of 1990, which required the Coast Guard to strengthen its regulations on oil tank vessels and oil tank owners and operators. Today, tank hulls provide better protection against spills resulting from a similar accident, and communications between vessel captains and vessel traffic centers have improved to make for safer sailing.
OIL SPILLS Spills occur at offshore oil drilling rigs during natural disasters (Katrina) and due to human error. They are called blowouts Spills occur from tanker accidents. Damage to environment from oil spills is dependent on type of oil (crude oil most toxic due to benzene and toluene), weather conditions, season, and type of organisms in the area. Oils spill cleanup is difficult and EXPENSIVE. It is very difficult to save animals who have ingested the hydrocarbons into their digestive tracts, especially aquatic birds who preen to insulate themselves.
FORMALDEHYDE Formaldehyde emitted from common building materials. Formaldehyde exposure has caused cancer in laboratory rats. Can also cause dizziness, nausea and headaches.
CIGARETTE SMOKE 1.Cigarette Smoke (first hand or second hand); CO gas from smoking reacts with hemoglobin in RBC and decreases oxygen in the blood stream. This results in impaired perception and thinking, slower reflexes, headaches, drowsiness, dizziness, and nausea. People who have heart disease are at risk of having heart attacks. People with respiratory sensitivity or disease can experience bronchitis, emphysema, and anemia.
(odorless, tasteless, colorless). It is a product from the radioactive decay of uranium 238 which is present in granite and shale bedrock. RADON-222-GAS Harmful when it seeps upward through the soil into basements through foundation cracks or into the groundwater. It can build to dangerous levels, cling to particles and become lodged in lung tissue. - If inhales, lung tissue is exposed to ionizing radiation from alpha particles and may produce lung cancer. - To test for radon-222: purchase a home- testing kit for 20-100 dollars. - New Jersey high area for Radon-222 due to much bedrock of granite and shale. -
ASBESTOS Asbestos A silicate mineral (amphibole) used in building materials for fireproofing. ONLY dangerous when it is airborne. The asbestos shard-like fibers cause lung cancer and mesothelioma (cancer in the lining of the chest cavity).
Problems with DDT DDT is soluble in fats; when organisms digest DDT, the pesticide concentrates in fatty parts of the body. This allows DDT to be passed along in the food web (bioaccumulate) and since organisms higher in higher trophic levels require more food to obtain their energy, DDT is biomagnified. Predatory birds at the top of the food chain lay eggs with unusually thin shells so that when hens sit on the nest, the eggs break and no offspring are born. DDE blocks the formation of calcium in egg production in the female. The eggs are formed from calcium carbonate in the female. Without the correct production of calcium carbonate, the eggs are produced too thinly. This caused the near extinction of the American bald eagle, osprey, and peregrine falcon.
Rachel Carson In 1958 DDT was sprayed to control mosquitoes near the home and private bird sanctuary of one of Rachel s friends (Olga Huckins). Initially, she found there was no independent critical research on environmental effects of pesticides. Carson surveyed the scientific literature and methodically built her case against the widespread use of pesticides. 1962 she published Silent Spring ; an allusion to the silencing of robins, catbirds, doves, jays, and wrens and scores of other bird voices because of their exposure to pesticides. She pointed out that for the first time in the history of the world, every human being is now subjected to dangerous chemicals, from the moment of conception until death.
