研究发现全世界40%的死亡是由环境污染

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研究发现全世界40%的死亡是由环境污染
by  http://www.medicalnewstoday.com/articles/79619.php
康奈尔大学一研究者推断全世界大约40%的死亡是由水、空气和土壤污染造成的。世界卫生组织近来报道环境恶化和世界人口的增多是人类疾病迅速增多背后的主要原因。他说这两方面的因素都导致了37亿人营养不良和疾病易感。
康奈尔大学生态学、农业科学教授David Pimentel和康奈尔大学研究生组研究了120多篇关于人口增长、营养不良和各种环境恶化对人类疾病影响的已发表的论文的数据。他们的报告已在在线版人类生态学杂志刊发（可在springerlink.com获得，印刷的刊物１２月份出版） “我们在水、土地和能源方面存在着严重的环境问题，这些接下来影响着食品生产、营养不良和发病率”，Pimentel说。Pimentel说与1950年25亿世界人口中20%营养不良相比，今天65亿世界人口中57%营养不良。根据研究营养不良不仅是每年600万儿童死亡的直接原因，而且使数以百万的人更容易患上急性呼吸道感染、疟疾这类易致死性疾病和其他威胁生命的疾病。研究中其他的主要观点:
* 近一半的世界人口拥挤在城市，经常没有足够的卫生设施，暴露于诸如麻疹和流感这类疾病的流行。
* 12亿人缺少清洁的水，水带来的感染占所有传染病的80%。越来越多的水污染成了携带疟疾的蚊子的孳生地，每年将1200万到2700万人致死。空气污染每年将大约300万人致死。不卫生的生存状况成为每年500多万人死亡的原因，其中一半以上是儿童。
* 来自吸烟和各种化学物质的污染每年将300万人致死。仅美国大约300万吨的有毒化学物质释放到环境中—导致癌症、出生缺陷、免疫系统缺陷和许多其它的健康问题。
*土壤被许多化学物质和病原污染，通过直接接触或通过食物和水传给人类。全球越来越多的土壤侵蚀不仅导致了更多的土壤流失而且播散了致病微生物和各种毒素。
同时，越来越多的微生物变得越来越有耐药性。全球变暖，加之生物多样性的改变影响了寄生虫的进化和外来物种侵袭新领地的能力。结果，诸如结核和流感这样的疾病作为更大的威胁重新出现，而新的威胁—包括西尼罗病毒和莱姆病—产生。 “越来越多的人需要纯水、充足的食物等基本需求。他们变得对营养不良和水、空气及土壤污染导致的疾病易感。” Pimentel总结道。他和一起的研究者们呼吁全面公平的人口政策和对支撑人类生命的环境资源的保护。 “依靠增加的疾病和营养不良限制世界人口降低了全人类的生活质量，是一个高风险的政策”。研究者们得出结论。

原文：
40 Percent Of Deaths Worldwide Caused By Pollution, Study Finds

Main Category: Water - Air Quality / Agriculture News
Article Date: 15 Aug 2007 - 14:00 PDT

About 40 percent of deaths worldwide are caused by water, air and soil pollution, concludes a Cornell researcher. Such environmental degradation, coupled with the growth in world population, are major causes behind the rapid increase in human diseases, which the World Health Organization has recently reported. Both factors contribute to the malnourishment and disease susceptibility of 3.7 billion people, he says.

David Pimentel, Cornell professor of ecology and agricultural sciences, and a team of Cornell graduate students examined data from more than 120 published papers on the effects of population growth, malnutrition and various kinds of environmental degradation on human diseases. Their report is published in the online version of the journal Human Ecology (available at springerlink.com, to be published in the December print issue).

"We have serious environmental resource problems of water, land and energy, and these are now coming to bear on food production, malnutrition and the incidence of diseases," said Pimentel.

Of the world population of about 6.5 billion, 57 percent is malnourished, compared with 20 percent of a world population of 2.5 billion in 1950, said Pimentel. Malnutrition is not only the direct cause of 6 million children's deaths each year but also makes millions of people much more susceptible to such killers as acute respiratory infections, malaria and a host of other life-threatening diseases, according to the research.

Among the study's other main points:

* Nearly half the world's people are crowded into urban areas, often without adequate sanitation, and are exposed to epidemics of such diseases as measles and flu.

* With 1.2 billion people lacking clean water, waterborne infections account for 80 percent of all infectious diseases. Increased water pollution creates breeding grounds for malaria-carrying mosquitoes, killing 1.2 million to 2.7 million people a year, and air pollution kills about 3 million people a year. Unsanitary living conditions account for more than 5 million deaths each year, of which more than half are children.

* Air pollution from smoke and various chemicals kills 3 million people a year. In the United States alone about 3 million tons of toxic chemicals are released into the environment -- contributing to cancer, birth defects, immune system defects and many other serious health problems.

* Soil is contaminated by many chemicals and pathogens, which are passed on to humans through direct contact or via food and water. Increased soil erosion worldwide not only results in more soil being blown but spreading of disease microbes and various toxins.

At the same time, more microbes are becoming increasingly drug-resistant. And global warming, together with changes in biological diversity, influence parasite evolution and the ability of exotic species to invade new areas. As a result, such diseases as tuberculosis and influenza are re-emerging as major threats, while new threats -- including West Nile virus and Lyme disease -- have developed.

"A growing number of people lack basic needs, like pure water and ample food. They become more susceptible to diseases driven by malnourishment, and air, water and soil pollutants," Pimentel concludes. He and his co-authors call for comprehensive and fair population policies and more conservation of environmental resources that support human life.

"Relying on increasing diseases and malnutrition to limit human numbers in the world diminishes the quality of life for all humans and is a high-risk policy," the researchers conclude.