Chapter 6 Pollution 第六章 污染

1 Pollution Type 污染类型

1.1 Air Pollution 空气污染

1.1.1 Types of Pollutants污染物的分类

●Primary air pollutants 初级空气污染物

初级空气污染物是指直接释放到空气中的污染物。

Primary air pollutants are released directly from their source into the atmosphere.

●Secondary air pollutants 次级空气污染物

次级空气污染物在初级空气污染物中发生一定的化学反应，然后将其产物释放到空气中。

Secondary air pollutants form as the products of chemical reactions that occur among primary pollutants and other chemicals present in the atmosphere.

1.1.2 Major Air Pollutants (the 6 US Criteria Air Pollutants) 主要的空气污染物（表1—6—1）

1.1.3 Photochemical Smog 光化学烟雾

光化学烟雾又称光化学污染，是由于大气中的有机物和二氧化氮发生光化学反应而形成的有害烟雾，通常在温度较高、汽车使用率高的城市发生。

The formation of photochemical smog requires cars and sunlight. Contents include photochemical oxidants (e.g., nitrogen dioxide, peroxyacyl nitrates, aldehydes). Warmer air temperatures increase the rate of smog formation; as a result, cities with warm, arid climates and lots of cars have the most photochemical smog.

Formation of photochemical smog:

NO2+VOCs+O2+uv→O3+PANs

1.1.4 Heat Island Effect 热岛效应

●热岛效应的形成

热岛效应是城市气候的典型特征，是指城市气温高于郊区气温的现象。城市中的热量主要来源于人们日常生活发出的热量。而城市中建筑比较密集，植被较少，城市暖气流上升，郊外冷气流下沉，形成以城市为中心的热岛。

Heat-absorbing properties of building materials, the presence of tall buildings that block cooling winds, and the operation of heat-generating cars, power plants, and other machinery, result in the temperature of a city being typically several degrees warmer than the surrounding natural areas. Because warmer air can hold more water vapor, rainfall can be as much as 30% greater downwind of cities when compared with areas upwind.

●热岛效应所带来的具体影响

Human activities create high levels of pollution in urban metropolitan areas. Urban heat islands can directly impact the health and welfare of urban residents who cannot afford air-condition. Urban heat islands can produce secondary effects on local meteorology, including the altering of local wind patterns, the development of clouds and fog, the number of lightning strikes and the rate of precipitation.

1.1.5 Temperature Inversions 逆温

一般情况下，温度是随高度的升高而降低的，但在某些情况下，温度有可能随高度的升高而增加，这种现象就叫作逆温现象。逆温现象形成的主要原因有：地面辐射冷却、空气平流冷却、空气下沉增温、空气乱流混合、锋面上形成的逆温。

Temperature inversions occurs when a layer of warm air sits atop cooler polluted air over a city and prevents the cool air from rising and dispersing its pollutants. Temperature inversions can trap pollutants over a city for several days or weeks; they are common over cities that are built in valleys or surrounded by mountains.

1.1.6 Acid Deposition 酸沉降

硫和氮的氧化物和水反应形成酸，随后形成酸沉降。氧化钙、碳酸钙等缓冲溶剂可以减缓酸沉降对环境的危害。

The oxides of sulfur and nitrogen can react with water to form acids, which then fall back to the earth as acid rain, snow, fog, hail, sleet, and the dry deposition of acidic particulates. So acid deposition has two parts: wet and dry. Wet acid deposition includes acidic rain, fog and snow. While dry acid deposition includes acidic gases and particles. It contributes to the damage of trees at high elevations and many sensitive forest soils through nitrogen saturation and creating acidic conditions that are unhealthy for decomposers and mycorrhizal fungi. What's more, acid rain accelerates the decay of building materials and paints, including irreplaceable statues and sculptures.

酸雨形成的化学式：

Lime (calcium oxide or CaO) or limestone (calcium carbonate or CaCO3) serves as a buffer that neutralizes the acids and minimizes ecosystem damage, and can also be added to soils to reduce the effects of acid deposition.

1.1.7 Indoor Air Pollution 室内空气污染

室内空气污染指由于各种原因，室内空气中的有害物质超标，从而影响人类的身体健康。这些有害物质包括：甲醛、苯、氨和放射性氡。近年来室内空气污染日益严重，甚至威胁到生命安全。

Exposure to cigarette smoke, radon, carbon monoxide, asbestos, bacteria, viruses, pollen, dust mites, mildew, mold, and yeast can be as detrimental to human health as exposure to outdoor air pollution especially without adequate ventilation.

1.1.8 Several Strategies to Improve Air Quality提高空气质量的几项措施

●政策措施

a．加强税收 Emphasizing tax incentives for pollution control

b．设立法定标准 Setting legislative standards for energy efficiency

c．增加研究经费 Increasing funding for research on renewable energy

d．激励减少气体污染 Incorporating incentives for reducing air pollution

e．减少煤炭使用 Reducing the use of coal and firewood in developing countries

f．提倡公共交通的使用 Providing incentives to use mass transit

g．逐渐废弃汽油发动机 Phasing out two-cycle gasoline engines

●法律措施

《洁净空气法案》Clean Air Act: It was passed by the US Congress in 1970, amended and renewed in 1977 and 1990. It establishes national standards for the allowable outdoor concentration of six criteria air pollutants to protect human health. The US Environmental Protection Agency (EPA) is charged with the enforcement of the Clean Air Act.

1.2 Noise Pollution 噪声污染

1.2.1 Noise Pollution 噪声污染

噪声污染是指人类在工业生产、交通运输、建筑施工等社会活动中产生干扰周围动物和人类正常生活的噪声。

Unwanted or disturbing sound interferes with normal activities such as sleeping, conversation, or disrupts or diminishes one's quality of life.

1.2.2 Human Health Effects对人类健康的影响

Human health effects include stress related illnesses, high blood pressure, speech interference, hearing loss, sleep disruption, and lost productivity.

1.2.3 Environmental Consequences对环境的影响

Environmental consequences include interference with ability to audibly detect predators or prey and the disruption of audible communication (bird song, whale song, etc.).

1.2.4 Sources 来源

●Wind farms 风力发电厂

Noise produced by windmills may interfere with local wildlife, decreasing the usable habitat.

●Sonar 声呐系统

Sonar used by military ships is linked to the disruption of migratory routes of marine mammals.

●Others 其他因素

Airports, construction equipment, lawn mowers, leaf blowers, trucks, motorcycles, jet skis…

1.2.5 Several Strategies to Control Noise Pollution控制噪声污染的几项措施

●政策措施

a. The use of noise barriers, limitations on vehicle speed, newer roadway surface technologies, limiting times for heavy-duty vehicles, computer-controlled traffic flow devices may reduce roadway noise.

b. Developing quieter jet engines and rescheduling takeoff and landing times may reduce aircraft noise.

c. New technologies in industrial equipment and installation of noise barriers in the workplaces may reduce industrial noise.

d. Controlling power tools, garden equipment and loud radios through local laws and enforcement may reduce residential noise.

●法律措施

《噪声控制法案》Noise Control Act: A national policy to control noise pollution in America.The act establishes a means for the coordination of federal research and activities in noise control, authorizes the establishment of federal noise emissions standards for products distributed in commerce, and provides information to the public respecting the noise emission and noise reduction characteristics of such products.

1.3 Water Pollution 水污染

1.3.1 Sources of Water Pollution 水污染的来源

水污染主要是由人类的各项活动产生的对水体的污染，包括农业污染、工业污染和矿业污染。

●Agricultural pollution 农业污染

农业污染包括了农药、化肥和动物粪便污染。大量使用农药使地表水污染严重，湖泊受到不同程度的富营养化危害，造成藻类和其他生物繁殖异常。

It is the leading cause of water pollution. Surface water runoff (nonpoint sources) carries with it eroding soil sediments, excess fertilizers, animal waste and pesticides into nearby waterways. 90% of drug prescriptions pass through the human body unaltered.

●Industrial pollution工业污染

工业污染指由于工厂种类不同，排出不同工业污染废物、废水，使水域受到毒性较大、较难处理的污染，比如重金属、工业酸、石油污染等。

Common pollutants generated from industrial processes include acids, heavy metals, fertilizers (nitrates and phosphates), pesticides, gasoline, motor oil, PCBs, and VOCs. Drilling and extraction operations for oil and gas can contaminate coastal waters and groundwater. The crude oil containing polycyclic aromatic hydrocarbons (PAHs), persists in the marine environment for years and is toxic to marine life. Chronic exposure to PAHs can affect the development of marine organisms, increase susceptibility to diseases, and jeopardize normal reproductive cycles in many ocean organisms.

●Mining pollution矿业污染

矿业污染指河流受到各种酸和重金属的污染。

Runoff carries sulfuric acid, arsenic, and cyanide used to extract gold. Erosion can also release heavy metals, such as mercury, from the rock layers. In addition, huge pools of mining waste slurry are often stored behind containment dams that often leak or infiltrate ground water supplies.（可参见前面章节关于矿业的描述）

●Others 其他水污染源

Nutrients营养物质：Phosphorus and nitrogen are plentiful in untreated water which causes cultural eutrophication.

Air pollution空气污染：Nitrogen oxides causes nutrient-type water pollution.

Microorganisms微生物：Bacteria, viruses and protozoa causes swimmers to get sick and fish get contaminated.

Noise噪声：Shipping, military sonar and recreational boating cause oceanic water noise pollution which make marine organisms hard to communicate, navigate and hunt.

Heat/global warming热量/全球变暖：Heat reduces the ability of water to carry oxygen. In this case, some organisms that cannot tolerate low oxygen levels may die.

1.3.2 Effects on Human Health 对人类健康的影响

水污染使人类的健康受到巨大的威胁。很多传染病的传播媒介都是水，比如腹泻、霍乱、伤寒等。

Unclean drinking water kills millions of people, mostly younger children, from preventable diseases like diarrhea, cholera, typhoid, shigella, polio meningitis and hepatitis.

1.3.3 Effects on Eco-environment 对生态环境的影响

●Cultural eutrophication 人为富营养化

人为富营养化是由于氮、磷等营养元素过量所造成的水质污染现象。这个现象主要是由于人类活动将未处理的工业、生活污水以及农业肥料排入湖泊、河流、海湾等地表水，使得各种浮游生物大量繁殖生长，特别是藻类。由于过量的生物在被污染的水域繁殖，该区域的氧气含量将会急剧下降，从而破坏了水域的生态平衡。

Cultural eutrophication occurs when waterways are inundated by excess phosphates and nitrates in runoff of fertilized cropland, urban lawns, animal feedlots, and the discharge of treated and untreated municipal sewage. The excess nutrients support large algal blooms, which block incoming solar radiation needed by the phytoplankton and submerged vegetation that sustain herbivorous fish populations. As aerobic bacteria decompose the algae, the dissolved oxygen concentration drops below a level that can support most aerobic aquatic organisms (fish), and biodiversity will decline.

There are several methods to control cultural eutrophication我们可以通过下列方法来控制人为富营养化：

a. Controlling the use of fertilizer

b. Controlling runoff from feedlots

c. Converting nitrates into nitrogen gas by denitrifying bacteria

d. Absorption of nutrients by planting vegetation

●Groundwater pollution 地下水污染

由于人类活动，地下水的化学成分、物理性质都有可能发生变化，导致水质下降。地下水污染过程缓慢，不容易被发现，而且很难治理。地下水污染的污染源有以下几类（见表1—6—2）：

1.3.4 如何应对水污染

●Water quality tests水质检测

我们可以通过温度、液流速度、浑浊度、pH等物理指标、化学指标和微生物指标来测试水质的好坏。水质检测可有106项检测指标，需要相应的仪器进行检测。

温度Temperature: The temperature of water impacts the solubility of oxygen and the range of tolerance of aquatic organisms.

液流速度River/Stream Flow Velocity: The velocity of a river or stream will impact the ability of oxygen to diffuse into the water. Fast-flowing water can diffuse oxygen faster than slower-moving water.

浊度Turbidity: Turbidity is the measure of the cloudiness of aquatic systems by suspended solids in the water column.

pH: This is a test to measure the hydrogen ion concentration to determine the acidity or alkalinity of a solution. Most organisms survive best in waters with a pH between 6 and 9.

溶解氧Dissolved Oxygen: This test will determine the amount of oxygen gas available in the water.

硝酸盐和磷酸盐Nitrates and Phosphates: Nitrogen-containing compounds and phosphates primarily act as nutrients in aquatic ecosystems since they are limiting factors for plant and algae growth.

硬度Hardness: This test determines the presence of some common metal cations such as magnesium (Mg2+) and calcium (Ca2+).

粪大肠杆菌Fecal Coliform: This assay is used to determine the possibility of fecal contamination from sewage, septic tank leaks, or animal wastes from feedlots.

氧垂曲线Oxygen-sag Curve: Oxygen-sag curve occurs in streams as bacteria break down degradable organic wastes and deplete the dissolved oxygen in the process.

●How to purify drinking water如何净化饮用水（图1—6—1）

●污水处理

现代污水处理工艺按处理程度可分为一级、二级和三级处理。

一级处理Primary treatment: physical process. Reducing oil, grease, fats, sand, grit and coarse solids through sand catcher, screens and sedimentation.

二级处理Secondary treatment: biological process. (Degrading of biological content of sewage by filters, activated sludge, filter beds, trickling filter beds and sedimentation.)

三级处理Tertiary treatment: Raising the effluent quality to the required standard by sand filtration, lagooning, constructed wetlands, biological or chemical precipitation, denitrifying bacteria, UV light and ozone.

●法律措施

《清洁水法案》Clean Water Act:Primarily regulates point-source pollution from municipal sewage facilities and industries and financing wastewater treatment systems.

《水质法案》Water Quality Act: Encourages the separation of storm water and sewer water lines.

《安全饮用水法案》Safe Drinking Water Act:Requires the US EPA to set standards of maximum containment levels for water pollutants that have negative health impacts for humans.

1.4 Solid Waste 固体废弃物

1.4.1 固体废弃物的来源

a. Industrial solid wastes 工业固体废弃物

Industrial solid wastes are solid waste generated by agricultural, mining, and manufacturing activities. Most of the solid waste generated in the United States comes from mining activities.

b. Municipal solid waste (MSW) 城市固体废弃物

MSW is what is typically referred to as trash or garbage that is thrown out by residential or commercial buildings.

c. Open dumps露天垃圾场

Open dumps are large fields or holes in the ground where garbage is deposited and often burned. Such dumps create significant environmental hazards through the uncontrolled release of harmful materials and the attraction of rodents and other vermin. In developing countries it is a common practice to dispose of waste in open dumps. Open dumping is forbidden in most developed countries.

d. Sanitary landfills卫生填埋

Specially prepared facilities in the US must meet specific requirements mandated by the Resource Conservation and Recovery Act. More than half of municipal solid waste in the US is buried in sanitary landfills.

e. Leachate渗滤液

As liquid moves downward through the layers of waste in a landfill, toxic materials leach out. This liquid can contaminate groundwater if it is not carefully monitored and controlled.

f. Incineration焚烧

Incineration can reduce the volume of solid waste up to 90%. Waste incineration can be used to produce steam to create electrical energy in waste-to-energy incinerators.

1.4.2 固体废弃物的类型（表1—6—3）

1.4.3 Reduction of Solid Waste 如何处理固体废弃物

a. Reduce consumption减少消耗

Reduce consumption of consumer products and energy. Simple ways to reduce consumption may be to walk, bike, or carpool to work, read newspapers or magazines online, and buy items secondhand. Reducing consumption requires less raw material input and therefore is a preventive measure, avoiding the production of waste from mining processes and air pollutants from energy production.

b. Reuse 重复利用

Reuse materials rather than relying on the production of one-time use items. For example, many consumers are now using refillable water containers rather than buying single-use plastic water bottles that are thrown out when finished. Plastics are made from a petroleum by-product and can take up to 1,000 years to break down. There are numerous examples of reusable items that can replace common consumer products such as cloth grocery bags instead of plastic, rechargeable batteries, and cloth napkins rather than paper.

重复利用固体废弃物虽然有好处，但也存在弊端（表1—6—4）。

c. Recycling回收

Recycle materials like paper, steel, aluminum, glass and some plastics to provide materials for new products. The United States currently recycles between 25～30% of its municipal solid waste. Composting is a type of recycling that utilizes the natural role of decomposing bacteria and fungi to convert biodegradable waste into usable soil amendments.

回收利用固体废弃物也有利有弊（表1—6—5）。

2 Impacts on the Environment and Human Health 污染对环境和人类的影响

2.1 Hazards to Human Health 对人类健康的危害

●Toxicity 毒性

Toxicity varies with the dose to which an organism is exposed and may have a threshold level below which no effects can be discerned.

●Acute effect 急性效应

Acute effect is an immediate response to exposure.

●Chronic effect 慢性效应

Chronic effect can occur from a single dose or long-term exposure to smaller doses of a toxin. This effect causes longer-lasting or permanent damage to the body, such as liver and kidney disease or even cancer.

●Dose-response curve剂量反应曲线

Dose-response curve is a graph of an organism's response to a given chemical plotted versus the dose received. The response is any negative health effect elicited from that particular material.

●LD 50 or median lethal dosage 半数致死剂量

LD 50 is the dose required to be lethal for 50% of the test population.

Non-threshold dose-response: The response or effect begins at zero and increases continuously with dosage.

Threshold dose-response: Harmful effects do not begin until the dose exceeds a threshold level.

化学危害物主要有以下几种（表1—6—6）：

2.2 Hazardous Chemicals to the Environment 对环境有危害的化学物质

2.2.1 Hazardous Waste 危险废弃物

Hazardous waste is the waste that is toxic, corrosive, flammable or dangerously chemically reactive. Developed countries are responsible for the large majority of the hazardous waste produced worldwide.

2.2.2 Strategies对策

a. Legal measures资源保护和重利用法令（表1—6—7）

b. Clean-up and Storage of Hazardous Waste 有害废物的清除和贮存（表1—6—8）

2.3 Economic Impacts 污染的经济影响

2.3.1 Cost/Benefit Analysis 成本效益分析

It is a decision-making process in which the costs and benefits are weighed and used to determine the best course of action. Often, when used to make decisions about the environment, this method requires placing a monetary value on elements that are difficult, or impossible, to value like human life, or the extinction of an endemic species.

成本效益分析可以用于估测政策改变，构想常规方案。具体规则如表1—6—9所示：

2.3.2 Externalities or External Costs 外部性和外部成本

Any negative effects on the environment or society associated with the production, use, or disposal of goods that are not included in their market price. For example, the production of paper pollutes the environment, and everyone in the society bears the environmental and social costs of

a. regulation prohibiting or limiting the activity

b. making the activity more costly through taxation—by setting the tax equal to the cost to others, the externality has been internalized

c. a hybrid approach that includes tradable licenses, with the number of licenses set by regulation and market determining the use of the licenses

2.3.3 Marginal Cost边际成本

In pollution cleanup, it refers to the cost of cleaning up each successive unit of pollution—generally the marginal cost rises exponentially as 100% cleanup is approached.

2.3.4 Decision-making决策

The following example of a series of considerations that might be taken into account about pesticide use illustrates the role economics plays in the decision-making processes that affect the environment:

The price of food is determined by the economic forces of supply and demand. The current price influences the decision of a farmer who must decide whether the cost of applying a pesticide to his or her crops is worth the additional yield that will result (a decision that weighs the marginal cost and the marginal benefit of additional pesticide use). The farmer does not consider external costs that will be borne by society, such as the ecological effects of pesticide runoff into waterways, the health effects to the workers who spray the fields, the residents who live nearby and consumers exposed to pesticide residues on food. If these external costs were borne by the farmer, it would influence the decision and could result in a different outcome that may increase the cost of food, decrease pesticide use, and improve the health of the population and the environment.

2.3.5 Sustainability 可持续发展

It is the practice of using a resource at a rate that is less than or equal to the rate at which it is naturally replenished.

●Renewable resources 可再生资源：They can be used sustainably; however, in many cases it takes a conscious effort to do so. Examples of renewable resources that are often depleted due to unsustainable use are timber, fertile soil, and fisheries.

●Nonrenewable resources 不可再生资源：By definition, when used, they are always used unsustainably; however, in the case of some metallic mineral resources (e.g., copper, iron, and aluminum), through reuse and recycling practices, they can be depleted at a rate that is slow enough to allow their reserves to last for hundreds of years.

可持续发展关注了以下几个问题（见表1—6—10）：