China learns of pollutant perils as the mercury rises
Beijing likes to vaunt its progress towards becoming a "green" city for the 2008 Olympics butit is more often a drab shade of grey.
So when Stephen Johnson, the top US environmental official, visited in April, it was little surprise that the capital's air pollution reached a maximum "grade five" - the worst on record in six years.
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But Mr Johnson, head of the Environmental Protection Agency, did not have to traverse the thousands of miles to China to be exposed to the most contaminated skies in the world. He could just as easily have experienced the effects of its pollution at home in the US.
In recent years the emissions generated by China's breakneck industrialisation have become more troublesome, not only for its neighbours but for faraway countries too. The most worrying export is airborne mercury, a dangerous neurotoxin spewed from coal-burning power and industrial plants.
According to emissions researchers, more than half the world's man-made mercury emissions come from Asia - and China is the main culprit. Some estimates indicate China accounts for between 25 and 28 per cent of global mercury emissions.
"China is the main emitter of mercury in the world and will continue to be in this position," says Josef Pacyna, a director of the Norwegian Institute of Air Research, which traces mercury discharges.
In an interview with the Financial Times, the EPA's Mr Johnson said mercury emissions and so-called "particulate matter", made up of a number of different components, were the China-made pollutants that now had the most direct impact on the US.
Mercury can accumulate in the atmosphere and travel thousands of miles before settling in waterways or in the ground, often through rainfall. Once deposited, micro-organisms can convert it to methyl mercury, a toxin that can then find its way into fish. "The most serious concern is that it contaminates fish and then it accumulates...and people eat fish," said Mr Johnson.
Young children and pregnant women are especially at risk. Mercury-contaminated fish can harm developing nervous systems, causing a range of mental and physical disabilities.
One place where toxins of all sorts, including mercury, amass is the Arctic, carried there in a process of "global distillation" by sea and air currents. Research cited by the Institute of Science in Society, which promotes critical public understanding of science, suggests Faroe Island children's pre-natal exposure to their mothers' intake of methyl mercury in whale meat was associated with nerve and blood defects at even relatively low levels.
The effects are also seen in wildlife, where mercury accumulates in tissues. Elizabeth Salter Green, director of the toxics programme for WWF UK, says: "What we are seeing is a mass contamination of Arctic wildlife that we believe is making these animals less capable of surviving the harsh Arctic conditions and the impacts of climate change."
The Chinese government has said it is taking steps to reduce toxic emissions. Wen Jiabao, prime minister, recently ordered local governments to release detailed information on energy consumption and emissions every six months.
He also instructed top environment officials to deal with the "extreme level" of China's pollution crisis. "We must spend money on pollution control sooner or later," Mr Wen was quoted as saying. But while Beijing has now passed a raft of environmental laws and regulations - and tried desperately to enforce them - the country's State Environmental Protection Administration has limited staff and authority.
"It's extremely weak," says Song Guojun, an environment professor at Renmin University. Prof Song argues Beijing ought to give Sepa the financial backing it needed to target large polluters, which are often shielded by local governments.
China's failure to limit its mercury discharges reflects its disproportionate reliance on coal and underinvestment in emissions-control technology.
Despite Beijing's plans to diversify its energy sources and reduce coal use, power demand continues to outstrip supply. And the government still lacks an effective system of incentives to persuade polluters to install emissions-control equipment while imposing serious fines on violators.
Mr Johnson said the US was willing to share leading-edge emissions-control technology with China. His agency is helping China to create monitoring and inventory systems for toxic air pollutants.
The EU has also proffered its assistance and is helping to finance the construction of a coal-fired power plant in China that will have "zero emissions" - neither of toxic substances nor greenhouse gases - and which it hopes may be a blueprint for other plants.
Environmentalists say the west is obliged to help China clean up. Dennis Pamlin, global policy adviser at WWF, argues: "China is now the factory of the world, which is causing this pollution, but the goods from China are consumed in the western world. The [pollution] must be seen in this context - this is a problem we share."
On the positive side, Mike Farley, director of technology policy liaison at Mitsui Babcock, a power plant technology company, says the modern coal-fired plants being built in China are more advanced than most in developed countries such as the UK.
However, another important source of mercury pollution from China is the cheap coal used for domestic heating and cooking. Mercury is also used and discharged in some mining processes, especially for gold. And it can be released naturally, through volcanic eruptions and the weathering of rocks.
Xu Muqi, a longtime environmental researcher at the Chinese Academy of Sciences, a state think tank, admits his country "definitely" has a role in mercury exports and more money needs to be spent to counter this.
He doubts there is evidence to link precise quantities of mercury deposition overseas to China, however. "Does it say 'Made in China'?" asks Prof Xu.
But a team led by Dan Jaffe, an atmospheric science professor at the University of Washington in Seattle, measured airborne mercury from the Japanese island of Okinawa and Mount Bachelor in Oregon and traced samples to their sources by analysing meteorological data, satellite imagery and chemical fingerprinting. His study concluded that emissions from China were "the most probable cause" of high mercury concentrations.
In the last comprehensive report to the US Congress on this issue, the EPA admitted that the complex chemical and physical transformations of mercury were "not completely understood". But as China's transformation into an industrial powerhouse continues, it is an issue the world will be unable to ignore.
中国：减少汞“出口”
北
京喜欢吹嘘，它为了2008年奥运会，正朝着“绿色”城市的方向迈进，但更多时候，它笼罩在一片灰褐色之中。
也就难怪，当美国最高环境官员斯蒂芬?约翰逊(Stephen Johnson)4月份访问北京时，首都的空气污染指数达到最大值“5级”――6年来的最差纪录。
但美国环保署(EPA)负责人约翰逊即使不横跨数千英里，飘洋过海来到中国，也会受到全世界污染最严重的天空之害。他在美国的家中，也很容易感受到中国污染的影响。
近年来，中国高速工业化产生的污染排放，不仅对其邻国、而且对遥远的国家也造成了越来越多的困扰。最让人担心的输出物是空气传播的汞，一种从燃煤电厂和工业工厂喷涌而出的危险的神经毒素。
据污染排放专家称，全球逾半数的“人为”汞排放来自亚洲 ―― 而中国是罪魁祸首。有估计显示，中国占全球汞排放量的比例在25%至28%之间。
挪威空气研究所负责人约瑟夫?帕奇纳(Josef Pacyna)称：“中国是全球最主要的汞排放国，而且还将继续保持这一地位。”该研究所追踪汞的排放情况。
美国环保署的约翰逊在接受《金融时报》采访时表示，在中国制造的污染物中，目前对美国影响最直接的，是汞排放和由多种不同成分构成的“颗粒物”。
汞能在大气层中积聚并飘浮成千上万英里，然后往往通过降雨落到水道或土壤中。一旦沉积下来，微生物能将其转化为甲基汞，这种毒素能够进入鱼体内。约翰逊说：“最严重的担忧是，它会污染鱼类，然后积聚起来……而人会吃鱼。”
儿童和孕妇尤其处在危险之中。食用受汞污染的鱼，会损害神经系统发育，导致一系列的精神和身体残疾。
北极是包括汞在内的各种毒素“汇聚”的地方之一，这些毒素是通过“全球蒸馏效应”(global distillation)过程，被洋流或气流带到那里的。“社会中的科学”研究院(Institute of Science in Society)引用的研究表明，在法罗群岛(Faroe Island)，儿童的神经和血液缺陷，与他们在出生前受到母亲从鲸肉中摄入的甲基汞的影响有关，即便甲基汞的含量相对较低。
这种效应也见于野生动植物界，汞会在它们的细胞组织内积聚。世界自然基金会英国分会(WWF UK)负责人伊丽莎白?萨尔塔?格林(Elizabeth Salter Green)表示：“我们目前看到的是北极野生动植物遭到大规模污染，我们认为这种污染正使这些动物的生存能力下降，从而难以在严酷的北极圈条件和气候变化影响下生存。”
中国政府已表示，正采取措施减少毒物排放。中国总理温家宝最近下令地方政府每6个月发布一次关于能源消耗和污染排放的详细信息。
他还指示高层环境事务官员们处理“相当严重的”中国污染危机。“污染治理的钱迟早要花，”温家宝说。但尽管中国政府通过了大量环保法律法规，并竭力执行这些法律法规，但中国国家环保总局的人手和权力都有限。
“这方面十分薄弱，”中国人民大学环境教授宋国君指出。他表示，北京应该给国家环保总局必要的财力支持，以对付往往受到当地政府庇护的大型污染厂家。
中国未能限制汞排放，表明中国对煤炭的依赖程度过大，而且在排放控制技术上投入不足。
尽管中国政府计划使能源来源多元化，并减少煤炭使用，但电力仍然供不应求。政府仍缺乏有效的激励体系，以劝说污染厂家安装控制污染排放的设备，并对违规者进行严厉罚款。
约翰逊先生表示，美国愿与中国分享最先进的污染排放控制技术。美国环保署正帮助中国创建有毒空气污染物监控和库存体系。
欧盟也已提供援助，目前正参与资助中国一座燃煤电厂的建设。该发电厂将实现“零排放”，即不排放有毒物质和温室气体。欧盟希望它成为其它电厂的样板。
环保人士称，西方国家有义务帮助中国清洁环境。世界自然基金会全球政策顾问丹尼斯?派姆林(Dennis Pamlin)认为：“中国目前已成为世界制造工厂，正在不断造成污染，但中国商品的消费者是西方国家。我们必须在这个背景中看待污染问题，这是我们共同面临的问题。”
从积极的方面看，电厂技术公司三井巴布科克(Mitsui Babcock)的科技政策联络主管迈克?法力(Mike Farley)称，目前正在中国兴建的燃煤电厂，比英国等发达国家的多数燃煤电厂都更为先进。
然而，中国汞污染的另一个重要源头，是用于家庭取暖和做饭的廉价煤。一些采矿作业也使用并排放汞，特别是开采金矿。同时，火山爆发和岩石风化也会自然地释放汞。
中国国家智囊机构 ―― 中国科学院长期从事环境研究的研究员许木启承认，中国“的确”在向世界输出汞污染，需要更多资金来解决这一问题。
但他怀疑，有证据表明确切数量的国外汞沉积与中国有关。“它有没有‘中国制造’的标记？”许教授问道。
由西雅图华盛顿大学大气科学教授丹?杰佛(Dan Jaffe)牵头的一个小组，对日本冲绳和美国俄勒冈州独身山(Mount Bachelor)空气中携带的汞进行了测量，并通过分析气象数据、卫星图像和化学指纹追踪样本的来源。他的研究得出的结论是，来自中国的排放，是导致汞浓度高的“最有可能的原因”。
在最近一份提交给美国国会的汞污染综合报告中，美国环保署承认，对于汞的复杂化学和物理变化，“还不是完全理解”。但随着中国继续向工业大国转变，这将是世界无法忽略的问题。
