中山大学环境科学概论Abstract

Populationo Globally, 1 in 4 people lives in extreme poverty 地球上四分之一人口生活在极端贫困的环境中•Cannot meet basic need for food, clothing, shelter, health 无法满足基本生活需求，如食物、衣着、居所、健康o Difficult to meet population needs without exploiting earth’s resources 如果不剥削地球的资源，人们的需要将无法满足Gap between Rich and Pooro Highly Developed Countries (HDC) 发达国家•Complex industrialized bases, low population growth, high per capita incomes 复杂的工业基础，人口增长率低，人均收入高•Ex: US, Canada, Japan 如美国、加拿大、日本o Less Developed Countries (LDC) 不发达国家•Low level of industrialization, very high fertility rate, high infant mortality rate, low per capita income 工业化程度低，极高的出生率，婴儿死亡率高，人均收入低•Ex: Bangladesh, Mali, Ethiopia 如孟加拉、马里、埃塞俄比亚Types of Natural ResourcesEcological Footprinto The average amount of land, water and ocean required to provide that person with all the resources they consume 满足个人对资源需求的土地、IPAT ModelMeasures 3 factors that affect environmental impact (I)) 对3个决定环境影响的因子的测算I = P A TI:Environmental Impact P:Number of people,A: Affluence per person T: Environmental effect of technologiesEnvironmental Sustainabilityo The ability to meet current human need for natural resources without compromising the needs of future generations 既满足现代人的需求以不损害后代人满足需求的能力o Requires understanding: 要求我们必须意识到•The effects of our actions on the earth 我们的行为对地球的影响•That earth’s resources are not infinite 地球资源不是无尽的Tragedy of the Commonso Garrett James Hardin (1915-2003)o Solving Environmental Problems is result of struggle between: 解决环境问题是斗争的结果，原因是•Short term welfare 短期福利•Long term environmental stability and societal welfare 长期环境可持续性和社会福利o Garrett used Common Pastureland in medieval Europe to illustrate the struggle他以中世纪欧洲的草原说明斗争Sustainable Developmento Economic development that meets the needs of the present generation without compromising future generations 经济发展既满足现代人的需求以不损害后代人满足需求的能力Environmental Problems, Their Causes, and ConsequencesPollutant—A substance or effect which adversely alters the environment by changing the growth rate of species, interferes with the food chain, is toxic, or interferes with health, comfort amenities or property values of peoplePollution—Found at high enough levels in the environment to cause harm to organisms.Point sourceNonpoint sourcePollutants can have three types of unwanted effects:Can disrupt / degrade life-support systems.Can damage health and property.Can create nuisances such as noise and unpleasant smells, tastes, and sights. Nature-Human Activity- Environment ConnectionsHuman Capital:Human Goods and servicesEconomic HeatAnd Depletion of nonrenewable resources Natural Capital:Cultural Degradation of renewable resourcesSystems Pollution and wasteThe major causes of environmental problems are:Population growthWasteful resource usePovertyPoor environmental accountingEcological ignoranceHeavy metal pollution汞mercury Hg镉Cadmium Cd铬chromium Cr铅Lead PbWhat is Water Pollution?any physical (temperature, oxygen), chemical (mercury), or biological (disease, sewage) change to water that adversely effects its use by living thingsWater pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater.It occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful constituents.Causes of Pollution (Water)Factors that contribute to water pollution can be categorized into two different groupsPoint sourcesNon-point sourcesPoint sources are the easiest to identify and controlNon point sources are ambiguously defined and harder to controlPoint SourcesSome point sources of water pollution includeWaste products from factoriesWaste from sewage systemWaste from power plantsWaste from underground coalminesWaste from oil wellsThey are called point sources because they are direct sources of water pollution and can be reduced and monitoredExample of a point source1.Sewage pipes2.Leaky gas tanks3.Industrial sites4.Injection wellsNon-point SourcesThe term non-point source encompasses a large range of sources such as:when rain or snow moves through the ground and picks up pollutants as it moves towards a major body of waterthe runoff of fertilizers from farm animals and crop landair pollutants getting washed or deposited to earthstorm water drainage from lawns, parking lots, and streetsNon-point source:1.Agriculture (soil, fertilizer,pesticides)2.Urban runoff (from pavement)3.Construction sites4.Air PollutionTypes of Water Pollution1.Biologicali.Infectious Disease(Pathogens)ii.Oxygen-Demanding WasteDirect (microbes in water):Typhoid, cholera, dysentery, hepatitis…Indirect(Water breeding carriers):malaria, yellow fever,west nile virus…2.Chemicali.Nutrients (Fertilizers)ii.Toxic Inorganic Materialsiii.Persistent Organic Pollutants (POP’s)1.Heavy metalsmercury,lead, tin…2.Super Toxic ElementsArsenic, selenium…3.Acids, salts, chlorine4.Radioactive Isotopes3.Physicali.Sedimentii.Thermal Pollutioniii.Solid WasteCauses:▪industry▪dams▪removal of vegetationAir PollutionCauses of Air PollutionOne of the main causes of air pollution is the release of carbon dioxide into the atmosphere, this happens because of Deforestation and fossil fuel burningSulfur dioxide is another air polluter and is released into the atmosphere by the burning of sulfur containing compounds of fossil fuels. Sulfur oxides are very dangerous to humans at a high concentration. Sulfur in the atmosphere is responsible for acid rainChlorofluorocarbons (CFCs) also contribute to air pollution by reducing the amount of ozone the stratosphere. CFCs come from a variety of places such as:the burning of plastic foam itemsleaking refrigerator equipmentspray cansNatural air pollutants can include:Smoke from wild firesMethane released from live stockVolcanic eruptionsAcid Rain•When emissions of sulfur dioxide and nitric oxide from stationary sources are transported long distances by winds, they form secondary pollutants such as nitrogen dioxide, nitric acid vapor, and droplets containing solutions of sulfuric acid, sulfate, and nitrate salts•These chemicals descend to the earth's surface in wet form as rain or snow and in dry form as a gases fog, dew, or solid particles, it is known as acid rain or acid depositionSmog•With the introduction of petroleum to replace coal economies in countries, photochemical smog has become predominant in many cities, which are located in sunny, warm, and dry climates with many motor vehicles •Worst episodes of photochemical smog tends to occur in summer Consequences continued•Sulfur dioxide, nitrogen oxides, ozone and peroxyacl nitrates (PANs), cause direct damage to leaves of crop plants and trees when they enter leaf pores (stomates)•Chronic exposure of leaves and needles to air pollutants can also break down the waxy coating that helps prevent excessive water loss and damage from diseases, pests, drought and frost•"In the midwestern United States crop losses of wheat, corn, soybeans, and peanuts from damage by ozone and acid deposition amount to about $5 billion a year". (Miller 498)Land PollutionFour Main causes of land pollution–Construction–Agriculture–Domestic waste–Industrial WasteConstructionBuildings take up resources and land, the trees are chopped down and used to make buildingsTakes away from places for animals and other organisms to live Consequences of Land Pollution•Land pollution exterminates wild life•Acid rain kills trees and other plants•The vegetation that provides food and shelter is destroyed•Land pollution can seriously disrupt the balance of nature, and, in extreme cases, can cause human fatalities•Pesticides can damage crops; kill vegetation; and poison birds, animals, and fish. Most pesticides kill or damage life forms other than those intended. For example, pesticides used in an effort to control or destroy undesirable vegetation and insects often destroy birds and small animals. Some life forms develop immunity to pesticides used to destroy themRegulating Hazardous Waste⏹Hazardous waste:Any solid, liquid or containerized gas that can catch fire easily, is corrosive to skin tissues or metals, is unstable and can explode or release toxic fumes, or has harmful concentrations of one or more toxic materials that can leach out.⏹Toxic waste:Form of hazardous waste that causes death or serious injury (such as burns, respiratory diseases, cancers, or genetic mutations).Characters of Hazardous WastesTreatments for Hazardous Wastes⏹Solidification(e.g. cement process)⏹Chemical methods(e.g. neutralization of acids and bases, redox process, sedimentation, etc.)⏹Biological/bio-chemical methods(e.g. bioremediation, phytoremediation, etc.)Two Emerging Trends in Hazardous Waste T reatment⏹Bioremediation uses microorganisms (usually natural or geneticallyengineered bacteria) and enzymes to convert toxic or hazardous substances into harmless compounds.⏹Phytoremediation uses natural or genetically engineered plants to absorb,filter, and remove contaminants from polluted soil and water.。