经济学人下载:针叶换取水资源(2)

The upshot is that biochar is good at pulling pollutants like lead out of water.
结果生物炭非常善于将铅等污染物从水中抽走。

And once a filter was saturated with the stuff, it would be a simple matter to replace it,
一旦过滤器被这一物质饱和，替换它将是一件简单的事情，

strip out the accumulated lead using nitric acid, and then burn or dump the exhausted biochar.
用硝酸除去积累形成的铅，然后燃烧或倾倒耗尽的生物炭。

Dr Mohan already knew, from previous work, that pine-wood biochar is an effective agent for stripping lead from water.
从之前的研究中，Mohan博士已经知道了松木生物炭是一种有效的铅脱除剂。

But pine wood is a valuable commodity, so he wondered if he could pull off a similar trick using another forest product—
但松木是一种昂贵的商品，所以他想知道是否可以用另一种林产品完成类似的任务——

one that currently has no value, namely pine needles.
一种目前不值钱的木产品，即松针。

To test this idea he and his colleagues went foraging for needles in the forests of Uttarakhand state, north-east of Delhi.
为了验证这一想法，他和他的同事去了德里东北的北阿坎德邦的森林里寻找针叶。

They returned their spoils to the laboratory, divided the needles into batches,
他们把找到的针叶带回实验室，将针叶分成几批，

and charred the batches in an electric furnace at temperatures ranging from 350-750°C.
然后分别在电炉中用350到750摄氏度的温度烧焦。

Experiments suggested that material charred at 550°C extracted lead most efficiently,
试验表明烤焦到550摄氏度的材料能最有效地提取铅，

and examination showed that this material had the largest internal surface area per gram
并且检验表明，这一材料每克中的内表面面积最大

(determined by a technique that measures a substance's ability to adsorb gases),
（由一种测量物质吸附气体能力的技术来测定的），

and the optimal level of carbonisation needed to preserve the metal-capturing organic compounds.
还有保存金属捕获有机化合物所需的最佳碳化水平。

The best temperature for the process, they discovered, was 35°C—just under body heat, and also ambient, at least in the summer,
他们发现，这一过程的最佳温度是35摄氏度——刚好低于体温，和常温，至少在夏天

in the wide plain south of the Himalaya through which the Ganges, one of the most polluted rivers on the planet, flows.
在喜马拉雅南部的广阔平原上是如此，且地球上污染最严重的河流之一——恒河流经这里。

Whether these laboratory observations can be turned into a practical process is hard to say.
这些实验室观察结果是否能够转为实践过程还很难说。

Special filtration-beds would have to be built in water-treatment plants—
水处理工厂中必须有特殊的过滤层——

facilities of which India is in any case woefully short. But it is not short of material to make the biochar.
而印度非常缺乏这些设施。但印度并不缺乏制造这种生物炭的材料。

An average hectare of Himalayan conifer forest produces over six tonnes of needles a year.
喜马拉雅针叶林平均一公顷每年生产6吨以上的针叶。

The process of charring would reduce this to two tonnes, but that is still a fair yield.
烤焦过程将使这个量减少至两吨，但这仍是一个合理的产出。

How much of this fallen foliage would need to be removed to reduce the fire risk and gain the other potential benefits,
需要处理多少落叶才能降低风险，并获得其他潜在益处，

and what further effects this might have on the local ecology, remain to be determined.
这一做法会进一步对当地生态产生怎样的影响，这些仍有待确定。

But Dr Mohan's work does show how the cost of this removal might be turned into a benefit enjoyed by all.
但Mohan博士的研究确实表明，清除这些针叶的成本可能会如何转变成所有人都能享受的利益。