But toxins don’t have to enter the water system to cause disruption. In Utah in 2016, a massive algal bloom on Utah Lake tainted the water that residents in three counties use as untreated “secondary water” for their lawns and gardens. Officials were unable to determine if food grown with the contaminated water was safe to eat. As the algae spread, one secondary system after another opted to exercise an abundance of caution and close its valves. Residents switched to watering their lawns with drinking water, causing citywide shortages.
但毒素并不一定要進(jìn)入水系統(tǒng)才會(huì)造成破壞。2016年在猶他州，猶他州湖上的大規(guī)模海藻爆發(fā)污染了三個(gè)縣居民用來澆灌草坪和花園的未經(jīng)處理的“二次水”。政府無法確定用受污染的水種植的食品是否安全。隨著藻類的擴(kuò)散，二級(jí)系統(tǒng)一個(gè)接一個(gè)非常謹(jǐn)慎地選擇關(guān)閉閥門。居民轉(zhuǎn)而用飲用水澆灌草坪，造成全市缺水。
Algal toxins in drinking water is not a rare event, Mishra says. “They’re always there,” he says. “It’s just that a lot of them go undetected.” The question is whether low-level consumption is harmful. Mishra suspects that if the exposure is long-term, there could be cumulative damage to the liver and brain. Unfortunately, with research focused on trying to understand how, and when, these toxins kill, there are few studies on public health consequences.
米什拉說，飲用水中的藻類毒素并非罕見。“其實(shí)藻類毒素一直存在，”他表示。“只是大部分一直未被發(fā)現(xiàn)。” 問題是少量進(jìn)入人體是否有害。米什拉懷疑，如果長期接觸，可能會(huì)對(duì)肝臟和大腦造成累積損傷。不幸的是，由于研究集中在試圖了解這些毒素如何以及何時(shí)殺死這些毒素上，很少有關(guān)于公共衛(wèi)生后果的研究。
The lack of good treatment options has led the Water Research Foundation to recommend a multistage approach combining several methods of decontamination. That could require treatment plant renovations that run into the millions of dollars. Many states are taking aim at the algal blooms themselves, attempting to starve the cyanobacteria by reducing nutrients like nitrogen and phosphorus, present in fertilizers and discharge from sewage plants. Kansas has an annual budget of over $5 million dedicated to limiting the amount of fertilizer and wastewater in waterways used as drinking water sources.
由于缺乏良好的處理方法，水研究基金會(huì)建議采用一種結(jié)合多種凈化方法的多級(jí)方法。這可能需要花費(fèi)數(shù)百萬美元對(duì)處理廠進(jìn)行翻修。許多州將矛頭對(duì)準(zhǔn)了藻華本身，試圖通過減少化肥和污水處理廠排放的氮和磷等營養(yǎng)物質(zhì)來餓死藍(lán)藻細(xì)菌。堪薩斯州每年有超過500萬美元的預(yù)算，用于限制用作飲用水水源的化肥和廢水的數(shù)量。
But Oregon isn’t taking any chances; cities in the state are already investing in expensive new treatment plants. “This appears to be a new normal for us,” says Modie.
但俄勒岡州不會(huì)冒任何風(fēng)險(xiǎn)；該州的城市已經(jīng)在投資興建昂貴的新處理廠。“這對(duì)我們來說似乎是一種新常態(tài)，” 莫迪亞表示。
譯文由可可原創(chuàng)，僅供學(xué)習(xí)交流使用，未經(jīng)許可請(qǐng)勿轉(zhuǎn)載。
評(píng)論
打印
