環(huán)境生態(tài)學(xué)---第二十三章空氣、水和土壤污染物(完整版)
【正文】 oil pollution Related topics The properties of water (D1) Greenhouse gases and global Soil formation, properties and warming (W2) classification (G3) Ozone depletion (W3) 土壤污染 在導(dǎo)致土壤污染問(wèn)題的一系列化學(xué)物質(zhì)中，鹵素（主要是溶劑和殺蟲(chóng)劑）構(gòu)成了最大的一類。 砷 ? 砷 是廣泛分布于自然界的非金屬元素，環(huán)境中的 砷 常以化合物形式存在。早期表現(xiàn)為咽痛、咳嗽、胸悶、氣短、頭暈、惡心、全身酸痛、無(wú)力、發(fā)熱等，嚴(yán)重時(shí)可出現(xiàn)中毒性肺水腫或化學(xué)性肺炎，中毒者高度呼吸困難，咯大量泡沫血色痰，可因急性呼吸衰竭而危及生命。在過(guò)去的一個(gè)世紀(jì)中，二氧化碳濃度升高，而全球氣溫也上升了 ~℃ 。 3 Prior to the development of the stratospheric ozone layer which forms the ‘ozone shield’ the evolution of terrestrial life was inhibited. DNA efficiently absorbs UV light, which seriously disrupts DNA replication, causing reproductive failure and death. Relatively small increases in UV radiation can cause mutations during the replication process that may result in the production of cancerous cells. A major concern is the potential damage caused by UV light to plants. Which could reduce primary productivity, and therefore affect whole ecosystems. The importance of the ozone shield Chlorofluorocarbons (CFCs) can degrade ozone in the stratosphere. Attention was focused on the problem when the British Antarctic Survey demonstrated a strong depletion of the Antarctic ozone shield. It is estimated that a single chlorine atom can breakdown 10 000 ozone molecules. If the trend of ozone loss continues it is predicted that the ozone shield will be depleted by a further 10% by 2050。如果按臭氧損失的現(xiàn)行趨勢(shì)發(fā)展下去，預(yù)計(jì)到 2050年，臭氧屏將再缺損 10%，這會(huì)增加 3億皮膚癌患者。 DNA大量吸收紫外線，而紫外光會(huì)嚴(yán)重破壞 DNA的復(fù)制，導(dǎo)致繁殖的失敗和死亡。因?yàn)榇髿庵械臏厥覛怏w（包括水蒸氣、二氧化碳和其他人為污染物）能夠吸收熱量，所以圍繞地球的大氣層防止了地球熱量的全部喪失
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