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1、W1 空气、水和土壤污染物,要 点,空气污染,空气污染是由人类活动引起的天然与合成的有害物质向大气中的排放。污染物可直接进入大气（初级污染物），或在太阳辐射的影响下于大气中产生（次级污染物）。已表明会给环境和健康带来威胁的主要空气污染物包括氧化氮类、二氧化硫、臭氧和固体颗粒。空气污染也能改变气候以及土壤、湖泊和河流的化学性质。,笼罩着空气污染的城市,Water bodies in northern temperate regions of Europe and North America have suffered form acidification due to acid rain is
2、a result of fossil fuel burning, which produces sulfur oxides (SOx) and nitric oxide (NO) which may combine with atmospheric water to form sulfuric acid (H2SO4) and nitric acid (HCO3), respectively, The term acid deposition is more accurate as acid may also be deposited from the air in the form of s
3、now, sleet and fog. Acid rain reduces the pH of soil and lakes, while acidification can also cause the death of trees and allow toxic metals (e.g. aluminium and mercury) to be leached from soils and sediments.,Acid rain,酸 雨,欧洲和北美的北温带地区的水体已经遭受到酸雨带来的酸化。酸雨是化石燃烧的结果。化石燃料的燃烧会产生氧化硫类物质（SOx）和一氧化氮（NO），它们能分别和大
4、气中的水分结合而形成硫酸（H2SO4）和硝酸（HNO3）。这种现象称为“酸降”更恰当，因为酸也会以雪、雨和雾的形式从空气中沉降下来。酸雨降低土壤和湖泊的pH，同时酸化也能导致树木的死亡，并使得有毒金属（如铝和汞）从土壤和沉积物中释放出来。,酸雨形成,因酸雨致死的树木,Water pollution can be divided into one of four categories: (i) biological agents, (ii) dissolved chemicals, (iii) nondissolved chemicals, and (iv) heat. The eutrophi
5、cation of aquatic ecosystems occurs due to an excess of inorganic nutrients. Organic matter in the water is broken down by microorganisms that deplete the oxygen levels, which may be quantified by the biochemical oxygen demand (BOD). A particularly important class of organic water pollutants is the
6、family of polychlorinated biphenyls (PCBs), a group of stable chlorinated compounds, that are highly toxic to vertebrates.,Water pollutants,水体污染物,水污染分为四类：（i）生物试剂，（ii）溶解的化学物质，（iii）不溶的化学物质和（iv）热。水生态富营养化是无机营养物过剩造成的。水中的有机物质被微生物分解，降低了溶氧水平。溶氧水平可以由“生化需氧量”（biochemical oxygen demand, BOD）来定量。有机水体污染物中非常重要的一类是
7、多氯联苯族化合物PCBs，这是一组稳定的含氯化合物，对脊椎动物有剧毒。,水污染,A range of chemical cause soil pollution problems, of which halogens (primarily solvents and pesticides) constitute the largest group. These chemicals are manufactured. The most complex group of compounds which are found polluting soils include polymers such a
8、s nylon, plastics and rubber. Bioremediation is a technique of utilizing microorganisms for the decontamination of polluted soils.,Soil pollution,Related topics,The properties of water (D1) Greenhouse gases and global Soil formation, properties and warming (W2) classification (G3) Ozone depletion (W
9、3),土壤污染,在导致土壤污染问题的一系列化学物质中，卤素（主要是溶剂和杀虫剂）构成了最大的一类。这些化学物质是人工制造的。污染土壤的最复杂的一类化合物包括多聚物，如尼龙、塑料和橡胶。生物除污是利用微生物净化污染土壤的一项技术。,相关主题,水的特性（D1） 温室气体和全球变暖（W2）土壤形成、特性和分类（G3） 臭氧（W3）,常见的元素有毒物质,汞 铬 砷 镉 铅 氟,朱砂(HgS),铬的毒性,所有铬化合物浓度过高时都有毒性，但各种铬化合物毒性的强弱不同。金属铬很不活泼，二价铬化合物一般认为是无毒的。三价铬进入人体过多时，可对人体健康带来危害，但三价铬的毒性较小，而六价铬毒性较大。 铬酸盐毒性
10、大，由于溶解度大且易被迅速吸收，对生物组织有刺激性和毒性。,砷,砷是广泛分布于自然界的非金属元素，环境中的砷常以化合物形式存在。砷是一种古老的毒物，公元前5-3世纪我国的战国时期已能用毒砂(砷黄铁矿)、砒石等含砷矿物烧制砒霜(As2O3)。李时珍在本草纲目中记载砒霜毒性很强。砒霜是最常见的砷化物，口服50mg即可引起急性中毒，60-600mg(一般200mg)可致死，儿童的最低致死量为1mgkg体重。,镉中毒,镉为银白色软金属，富有延展性。通过镉及其化合物经食物、水和空气进入人体后产生的毒害作用。有急性、慢性中毒之分。工业生产中吸入大量的氧化镉烟雾可发生急性中毒。早期表现为咽痛、咳嗽、胸闷、气
11、短、头晕、恶心、全身酸痛、无力、发热等，严重时可出现中毒性肺水肿或化学性肺炎，中毒者高度呼吸困难，咯大量泡沫血色痰，可因急性呼吸衰竭而危及生命。,铅的毒性,美国环境保护署(EPA)：铅及其化合物是17种严重危害人类寿命与自然环境的化学物质之一； 工业废弃品中的铅通过渗入地下水系统而进入动物或人类的食物链； 人体中存在过量的铅将导致神经和再生系统紊乱、发育迟缓、血色素减少并引发贫血和高血压； 美国职业安全与健康管理署(OSHA)标准：成人血液中铅含量应低于50mg/dl，儿童血液中铅含量应低于30mg/dl。,氟中毒,Carbon dioxide (CO2) is the main vehicl
12、e of carbon flux between atmosphere, oceans and biota. Fossil fuels (coal, oil and natural gas) present in the lithosphere lay dormant until recent centuries. The concentration of CO2 in the atmosphere has increased from about 280 parts per million (ppm) in 1750 to about 350 ppm in 1990 and is still
13、 rising, with the main reason for the emissions, and the concentration to be expected in the atmosphere vary, but is appears likely that the concentration will rise to a mean of about 550 ppm by the year 2050.,Key Notes,Carbon dioxide concentrations in the atmosphere,W2 GREENHOUSE GASES AND GLOBAL W
14、ARMING,W2 温室气体和全球变暖,要 点,大气中二氧化碳的浓度,二氧化碳（carbon dioxide）是大气、海洋和生物区系中碳循环的主要载体。存在于岩石圈的化石燃料（煤、石油和天然气）直到最近几个世纪才被挖掘出来。大气中二氧化碳的浓度从1750年的280ppm上升到1990年约350ppm，而且仍在增长。增长的主要原因是化石燃料的燃烧。虽然对于未来二氧化碳的释放量和大气中二氧化碳的估计浓度尚有不同，但是到2050年，二氧化碳浓度很可能上升到平均大约为550ppm。,挪威斯瓦尔巴特群岛：二氧化碳的试验倾倒场,The greenhouse effect is a theory which
15、 proposes that pollution by common anthropgenic (i.e. created by humans) pollutants such as CO2 and methane may lead to an increased global temperature. Over the last century, CO2 concentrations have risen and global air temperatures have increased by 0.4-0.7, which supports theory theory. The atmos
16、phere formed around the Earth insulates the planet form the full effects of hat loss by trapping heat in the atmosphere using greenhouse gases, which include water vapor as well as Co2 and other anthropogenic pollutants. Doubling of the atmospheric CO2 and other anthropogenic pollutants. Doubling of the atmospheric CO2 concentration from its present level is predicted to lead to a further warming of around 3.5 .,The greenhouse effect,Rel
