文：扎利亞·高威特 （Zaria Gorvett）
Image copyrightGETTY IMAGES
“如果我是你，我是不會喝的。”
我非常不雅的趴在泰晤士河的水泥岸上，俯身用一隻空瓶子從河裡舀起綠色渾濁的水。場景十分混亂。一個不同尋常的大浪讓我措手不及，河水濺濕了我的衣袖。飢餓的海鷗從各個方向飛落下來。一大群鴨子前來探察——兩隻巨大的鵝發出嘶嘶聲。
這個建議來自旁邊一條船上的人。他一臉迷惑且愉快的觀察了我一會兒。我還沒來得及告訴他，我就是要喝這個水，他就消失在了甲板下。
這個瘋狂的計劃來自一個驚人的事實。根據世界衛生組織的數據，在地球這顆藍色星球上，有大約21億人沒有安全的飲用水源。所以，每年因飲用不潔水源而喪生的人數超過了包括戰爭在內的任何暴力事件。
Image copyrightGETTY IMAGES Image caption泰晤士河在流入倫敦之前十分平靜，並且較為潔凈，進入倫敦以後可能受到了下水道排水的污染（圖片來源：Getty Images）
隨著全球人口增長和氣候變化，水資源問題正在變的日益嚴重。到2025年，全球一半的人口將生活在安全水資源供不應求的地方。
我們會迎來新一代大膽的解決方案，包括以糞便為原料的凈水器，還有用氣泡水過濾顆粒物的機器。其中之一就是吸管LifeStraw，水流經塑料管道中的一捆長長的空心纖維以完成凈化。
LifeStraw最初版本的工作原理就像普通的吸管一樣。就是把一頭插到水中，從另一頭吸水。任何超過兩微米或頭髮直徑百分之一的東西都會堵在吸管里，無法進入你的嘴巴。這就過濾掉了99.9%的寄生蟲和99.9999%的細菌，比如那些會導致霍亂，痢疾和傷寒的細菌。當你用LifeStraw吸水時，就算是最渾濁的水也會變的像山泉水一樣清澈。
這一切是從1996年開始的。當時的一位名叫米克爾·弗蘭德森（Mikkel Frandsen）的丹麥企業家把他祖父的制服製造公司轉型成專注於改善非洲人生活的公司。LifeStraw最初的版本就是為了消滅麥地那龍線蟲，它是到21世紀仍然殘存的最可怕的疾病之一。
病因就像俄羅斯套娃一樣重重疊疊——被跳蚤、幼蟲污染的水源。如果你不幸喝到了這種水，在接下來的幾個月里，蠕蟲會在你的體內成熟、繁殖，最後會從皮膚表面鑽出來。通常的結果就是出現感染，有時還會截肢。患者會非常痛苦，沒有疫苗或藥物能夠治療這種病。
起初，吸管安裝了一片簡單的金屬網，用來過濾相對較大的跳蚤。在過去的二十年里，弗蘭德森的公司為了消滅這種疾病供應了超過3700萬件產品。在它的幫助下，麥地那龍線蟲的病例從1986年的350萬例減少到去年的25例。”這是它消滅的第二種疾病，”LifeStraw的營銷主管馬特·德維特（Matt DeWitte）說。
Image copyrightGETTY IMAGES Image caption吸管的研製是為了抗擊非洲致人衰弱的寄生蟲麥地那龍線蟲。（圖片來源：Getty Images）
如今，這一技術已經進步到僅憑一根吸管就可以過濾掉4000升水中的所有細菌、寄生蟲和跳蚤，可確保該產品的所有者在數年內安全無虞。與此同時，更大規模的、以重力為動力的版本在海地、厄瓜多、巴基斯坦和泰國的災後得到使用。該公司在為肯亞的一百萬學生提供清潔飲用水的工作也已進行過半。
為了實際體驗一下這個難以置信的技術，我來到了我能找到的倫敦最讓人噁心的水源——泰晤士河——測試LifeStraw的原始版。但是風險到底有多大？還有，為什麼我們要在意這一點？
“泰晤士河裡的病原體非常多，”英國自然環境研究理事會生態學和水文學中心（NERC Centre for Ecology & Hydrology）資深科學家安德魯·辛格（Andrew Singer）說。當我告訴他LifeStraw的事時，他開心的笑了：”你的實驗肯定能測試出它的效果。”
事實上，1500萬倫敦人排出的污水很大一部分都進入了泰晤士河。”與人口相比，這條河的水量並不大，這就意味著對污水的稀釋能力不足。”在不同的時候，下水道污水占倫敦河流的比例在10%到100%之間。通常來說，這些下水道污水是經過處理的，不過也有未經處理的情況。
儘管很多人會認為”經過處理的”下水道污水是比較乾淨的，事實卻並非如此。”病原體數量會減少，但是除此之外我們什麼都不能保證，”辛格說。大多數河流中最危險的東西是兩種寄生蟲——隱孢子蟲和梨形鞭毛蟲。它們會導致腹瀉，並且孢子非常小，很難殺死。它們有時候會進入自來水。
相反，下水道處理的主要目標是減少有害微生物和有機物的數量。後者是關鍵，因為隨著碎屑的腐爛，它會吸收水中的氧氣，有可能對水體中的野生動物造成毀滅性影響。
Image copyright GETTY IMAGES 密西根州弗林特的水污染在美國成了一則大新聞（圖片來源：Getty Images）
污水還攜帶高劑量的藥品。2013年對全球污水處理廠的一項研究發現處理工作只能清除42種物質中的一半，比如咖啡因和抗生素。
還有下雨時流入河中的所有東西，包括殺蟲劑、除草劑、動物糞便，以及少量有毒金屬，比如鎘——”它們被當作’營養補充品’喂給飼養的動物，目的是促進生長，”辛格說。還有倫敦很多鴨子、海鷗和老鼠排出的東西。”它會被稀釋，但是不會到你找不到的地步。所有東西都在那裡。”
最後，還有塑料。2016年的一項研究發現，泰晤士河的樣品中有大約35,000個塑料顆粒，大多數來自食品和飲料容器。
這種污染有很多讓人不悅的副作用。跨性別和愚蠢的魚在被避孕藥、塑料——類似於雌激素的化學原理——和抗抑鬱藥污染的水體中遊蕩時，會把塑料當成輕易可得的獵物。這也意味著與河流打交道的風險特別大。比如，在泰晤士河裡舉辦游泳活動以後，常常會出現集體疾病。
“就工業化國家而言，泰晤士河相當典型。我無法想像會有很多河流竟然比印度很多地區的河流還要糟糕，”辛格說。
我很幸運，LifeStraw能消除其中可能潛藏的任何細菌和寄生蟲，還有塑料和相當多的泥土。剩下的東西只有可溶解的物質和非常微小的東西，比如金屬、病毒、殺蟲劑和除草劑。在這個問題上，辛格說的話讓人不太放心——”地球上存在的大部分細菌都會經過泰晤士河，”他說——但是我能依靠的只是它的數量很少。我不會把這件事變成習慣。
即便你不會魯莽到直接飲用河水，但河流污染可能並不像你願望中的那麼遙遠。如今，全球83%的自來水含有塑料纖維，而溶解在水中的雌激素被認為是男性精子數量快速下降的原因。
“水資源安全的問題並不止於微生物層面，”LifeStraw的董事總經理艾利森·希爾（Alison Hill）說，”雖然我們覺得水資源不安全主要是發展中國家的問題，但是在過去的五年中，像密西根州弗林特（Flint）這些地方讓我們看到這也同樣是美國的問題。”
Image copyright ZARIA GORVETT LifeStraw的製造者稱它能夠去除未經處理的水中99%的寄生蟲和細菌（圖片來源：Zaria Gorvett）
最近在美國密西根州弗林特的水危機中，10萬人處於鉛含量達到危險水平的用水環境中。這讓水污染的化學來源受到矚目。去年的一份報告發現，在過去十年中，6300萬以上的美國人暴露於不安全的飲用水環境中。水中含有工業污染物、超標化肥等等。
“存在兩大來源，”德維特說，”第一是全球污染日益城市化。這就意味著我們不僅要過濾生物污染物，還要擔憂重金屬、殺蟲劑和藥品等。另一個整體趨勢是，在美國這樣的國家出現的基礎設施老化現象，它導致人們必須立刻採取除鉛等行動。”
最後，我從泰晤士河取到了足夠的水，既沒有落水，也沒有被鴨子攻擊。為了避免再有陌生人側目，我決定回到公寓里再喝。
吸管的操作很簡單——只需要把一頭的保護蓋取下，把它放入你挑選的難喝的飲料中，然後像正常的吸管一樣使用它。
花了幾秒鐘，很快的一股剛剛經過過濾的河水就穩穩地被吸入我的口中。結論如何？它非常冰冷，並且清爽到讓我感到驚訝。我覺得我喝到了潮濕植被的味道，但是那大概只是我的想像。
而且，我沒有生病。
The Miraculous Straw That Lets You Drink Dirty Water
By Zaria Gorvett
Dirty water still kills millions of people every year. One ingenious invention can remove dangerous microbes as they flow towards your mouth. Would you drink it?
「I wouldn』t drink that if I were you.」
I』m sprawled inelegantly on the concrete banks of the Thames, leaning down to scoop some of its green, murky liquid into an empty water bottle. Already, it’s a scene of utter chaos. An unusually large wave has caught me off guard and sloshed water all up my sleeve. Hungry seagulls are swooping down from every direction. A large crowd of ducks has come to investigate – and two formidable geese are making hissing noises.
The advice is proffered by a man on a nearby boat, who has been watching me with an expression of amused bewilderment for some time. Alas, he disappears below deck before I can tell him that drinking the water is precisely what I』m going to do.
My mad plan begins with a startling fact. According to the World Health Organisation, some 2.1 billion people on our pale blue planet do not have a safe source of water to drink. Consequently, more people die from drinking contaminated water every year than from any form of violence, including war.
The Thames is quiet and cleaner before it enters London, where it can become polluted with sewage (Credit: Getty Images)
As the world’s population expands and climate change sets in, our water woes are becoming increasingly severe. By 2025, half the world’s population will be living where the demand for safe water exceeds its supply.
Enter a new generation of bold solutions, from water purifiers that run on faeces to machines that work by filtering out particles using fizzy water. One of these is the LifeStraw, which cleans water by passing it through a bunch of long, hollow fibres encased in a plastic tube.
The original version works like a normal drinking straw; you simply plunge one end into some water, then suck through the other. Anything larger than two microns, or a hundredth of the thickness of a human hair, will be trapped inside before it makes it to your mouth. This includes 99.9% of parasites and 99.9999% of bacteria, such as those that cause cholera, dysentery and typhoid fever. When sipped through a LifeStraw, even the muddiest water comes out as clear as a mountain spring.
It all started back in 1996, when a Danish entrepreneur, Mikkel Frandsen, transformed his grandfather’s uniform manufacturing business to focus on improving the lives of people in Africa instead. The earliest version of the LifeStraw was created to help eradicate guinea worm, one of the most gruesome diseases to survive into the 21st Century.
It’s caused by a Russian doll of nasty things – dirty water, infected with fleas, infected with worm larvae. If you』re unlucky enough to drink any, the worms will mature and breed within your body over several months, eventually popping up at the surface of the skin where they try to wriggle through. The end result is often infections and, occasionally, amputated limbs. It’s excruciatingly painful and there’s no vaccine or drug that can treat it.
To begin with, the straw contained a simple streel mesh that could remove the relatively large fleas. Over the past two decades, Frandsen’s company has supplied the eradication effort with more than 37 million of them, which has helped to reduce the number of guinea worm cases from 3.5 million in 1986 to just 25 last year. 「This will be the second disease ever eradicated,」 says DeWitte.
The straw was designed to beat guinea worm, a debilitating parasite found in Africa (Credit: Getty Images)
Today the technology has evolved to the point where a single straw can filter all the bacteria, parasites, and fleas from 4,000 litres of water, enough to keep its owner safe for several years. Meanwhile scaled-up, gravity-powered versions have been used in the aftermath of disasters in Haiti, Ecuador, Pakistan and Thailand, and the company that makes them is over half way to providing clean drinking water to a million students in Kenya.
To see this incredible technology in action, I tested the original LifeStraw on the most disgusting liquid I could find in London: water from the Thames. But exactly how risky is this? And why should we care?
「There’s a very long list of pathogens in the Thames,」 says Andrew Singer, a senior scientific officer at the NERC Centre for Ecology & Hydrology. When I tell him about the LifeStraw, he laughs heartily. 「Well your experiment is certainly going to test it for sure.」
Though many of us assume that 「treated」 sewage is relatively clean, the reality is very different
In fact, a large proportion of what comes out of Londoners – around 15 million of us – goes into the Thames. 「The amount of water in there is quite low compared to the number of people, which means that we have less water to dilute what we put into it. Effectively our rivers are between 10% and 100% sewage at times,」 says Singer. Generally this is treated sewage, though occasionally it’s raw.
And though many of us assume that 「treated」 sewage is relatively clean, the reality is very different. 「Pathogens get reduced in number, but that’s about all we can reliably say,」 says Singer. The main dangers in most rivers are the parasites Cryptosporidium and Giardia lamblia, which cause diarrhoea and have spores so tiny and difficult to kill, they sometimes make it into tap water.
Instead, the primary aim of sewage treatment is to reduce the amount of harmful microorganisms and organic matter that it contains. The latter is crucial, because as debris decays, it tends to suck the oxygen out of water and can have a devastating impact on aquatic wildlife.
Water pollution in Flint, Michigan became a huge story in the US (Credit: Getty Images)
Sewage also brings with it a hefty dose of pharmaceuticals. One 2013 study of worldwide wastewater treatment plants found that just half of 42 substances present in sewage, such as caffeine and antibiotics, were removed by the treatment process.
Then there’s all the stuff that gets dragged into rivers when it rains. This includes pesticides, herbicides, animal waste, which includes small amounts of toxic metals such as cadmium – 「They』re fed to farm animals as 「nutritional supplements」, which is really just growth promotion,」 says Singer – and anything that the city’s many ducks, seagulls and sewer rats expel. 「It gets diluted, but not to the point where you can』t find it. It’s all there.」
Finally, there’s plastic. A 2016 study found some 35,000 plastic particles in samples taken from the Thames, mostly from broken down food and drinks containers.
As far as industrialised countries go, I』d say the Thames is pretty typical. I can』t truly imagine many rivers being worse than the rivers in those flowing in many parts of India – Andrew Singer
This pollution has a number of unpleasant side-effects, including transgendered and dopey fish that make easy prey, after swimming around in water contaminated with the contraceptive pill, plastics – which mimic the chemistry of oestrogen – and calming antidepressants. It also means that interacting with the river is particularly risky. For example, swimming events in the Thames are regularly followed by mass illness.
「As far as industrialised countries go, I』d say the Thames is pretty typical. I can』t truly imagine many rivers being worse than the rivers in those flowing in many parts of India,」 says Singer.
Luckily for me, the LifeStraw will remove any bacteria and parasites that might be lurking, as well as plastic and a fair amount of mud. All that will be left is anything dissolved or particularly small, such as metals, viruses, pesticides and herbicides. Here Singer isn』t exactly reassuring – 「Pretty much every virus that has ever existed on Earth is running through the Thames,」 he says – but I』m banking on these only being present in very small amounts. I』m not exactly going to make this a habit.
Even if you』re not reckless enough to drink directly from a river, the pollution in our rivers might not be as distant we』d like to think. Today 83% of tap water around the globe contains plastic fibres, while dissolved oestrogen is thought to be contributing to rapidly declining sperm counts in men.
「The issues with safe water don』t stop at microbiological,」 says LifeStraw’s Managing Director Alison Hill. 「And while we think of unsafe water as being predominantly limited to the developing world, I think what we』ve seen in the last five years, in places like Flint, Michigan, is that the issue of safe water is an American concern as well.」
The LifeStraw’s makers say that it can remove 99.9% of parasites and bacteria from untreated water (Credit: Zaria Gorvett)
The recent Flint water crisis, in which over 100,000 people were exposed to dangerously high levels of lead, has put the spotlight on these chemical sources of contamination. A report filed last year found that more than 63 million Americans were exposed to unsafe drinking water over the last decade, which may have contained anything from industrial pollutants to illegal quantities of chemical fertilisers.
「There are two main factors,」 says Matt DeWitte, Lifestraw’s head of marketing. 「One is that the global population is increasingly urbanised, and that means we have to move from filtering biological contaminants only, to also being concerned about heavy metals, pesticides and pharmaceuticals etc. The other overall trend that you see is in countries like the US specifically is the breakdown of infrastructure and that has created an immediate need to respond to things like lead removal.」
Eventually I managed to collect enough water from the Thames without falling in, or being attacked by ducks. To avoid any more looks from strangers, I decided to drink it from the safety of my flat.
Operating the straw is easy – you simply remove the protective caps from either end, dip it into an unpalatable drink of your choice, and use it like a regular straw.
It took a few seconds, but soon a steady stream of freshly filtered river water was flowing through. The verdict? It was icy cold and actually surprisingly refreshing. I thought I could detect notes of damp vegetation, but this was probably my imagination.
And no, I didn』t get sick.