Rivers around the world are contaminated with dangerous levels of antibiotics, according to a major new study. Concentrations of antibiotics in some waterways exceed safe levels by 300 times, a global team of scientists led by the University of York found.

The Thames was contaminated with five antibiotics, including levels of ciprofloxacin — used to treat skin and urinary tract infections — that were three times what is considered safe.

Researchers looked at 14 commonly used antibiotics in rivers flowing through 72 countries and found antibiotics were in two-thirds of samples.

Scientists fear antibiotics in rivers cause bacteria to develop resistance, meaning they can no longer be used in medicines for humans. The U.N. estimates that the rise in antibiotic resistance could kill 10 million people by 2050. “A lot of the resistance genes we see in human pathogens originated from environmental bacteria,” said Professor William Gaze, a microbial ecologist at the University of Exeter who was not involved in the study.

Drugs get into rivers via human and animal waste, as well as leaks from wastewater treatment and drug manufacturing sources.

In one site in Bangladesh, levels of metronidazole — which is used to treat mouth and skin infections — were 300 times greater than what is considered safe. The most common antibiotic was a urinary tract infection antibiotic called trimethoprim, which was present in 307 of 711 sites tested.

Scientists flew out 92 testing kits to partners across the world who took samples from local rivers. Researchers found Bangladesh, Kenya, Ghana, Pakistan and Nigeria were home to the most contaminated rivers. The team said that the safe limits were most frequently exceeded in Asia and Africa. However, sites in Europe, North America and South America also had high levels of contamination showing that antibiotic contamination was a global problem.

Professor Alistair Boxall, from the York Environmental Sustainability Institute, said, “The results are quite eye-opening and worrying, demonstrating the widespread contamination of river systems around the world with antibiotic compounds.

“Many scientists and policy makers now recognize the role of the natural environment in the antimicrobial resistance problem. Our data shows that antibiotic contamination of rivers could be an important contributor.

“Solving the problem is going to be a mammoth challenge and will need investment in infrastructure for waste and wastewater treatment, tighter regulation and the cleaning up of already contaminated sites.”

Words to Learn 相关词汇

【病原体】bìngyuántǐ pathogen a specific causative agent (such as a bacterium or virus) of disease

【巨大的】jùdà de mammoth of very great size

一项新研究显示，世界各地的河流都被抗生素污染了，污染程度已经达到危险水平。英国约克大学带领的国际科学家团队发现，一些河流的抗生素浓度超出安全值300倍。

泰晤士河被五种抗生素污染，其中用于治疗皮肤和尿路感染的环丙沙星水平超出安全值的两倍。研究人员在流经72个国家的河流中查找14种常用抗生素，并在三分之二的样本中发现了抗生素。科学家担心河流中的抗生素会导致细菌产生抗体，这意味着这些抗生素不能再用作人类药物。联合国预计，对抗生素耐药性的上升会在2050年前导致1000万人丧生。

英国埃克塞特大学的微生物生态学家威廉●盖泽教授告诉《卫报》说：“我们在人类病原体中看到的很多抗性基因都来自周围环境中的细菌。”盖泽教授没有参与这项研究。

抗生素药物通过人体和动物排泄物进入河流，污水处理厂和制药厂泄露的抗生素也会进入河流。在孟加拉国某地的河流中，甲硝唑水平超出安全值300倍。甲硝唑是用来治疗口腔和皮肤感染的。最常见的抗生素是治疗尿路感染的甲氧苄啶，在全球711处河流取样点中，有307处河水中都检测到了甲氧苄啶。

科学家向世界各地的合作机构分发了92套测试工具，用来从当地河流中提取样本。研究人员发现，孟加拉国、肯尼亚、加纳、巴基斯坦和尼日利亚的河流是受抗生素污染最严重的。研究团队称，亚洲和非洲的河流超出安全范围的频率最高。

不过，欧洲、北美洲和南美洲的河流也查出高水平的抗生素污染，这说明抗生素污染是一个“全球性问题”。约克环境可持续发展研究所的阿利斯泰尔●博克斯奥尔教授说：“研究结果让人瞠目结舌，也让人感到担忧。研究显示，世界各地的河川系统受到抗生素化合物的大面积污染。”

“现在许多科学家和决策者意识到了自然环境对耐药性问题的作用。我们的数据显示，河流受到的抗生素污染是产生耐药性的一个重要原因。”

“解决这个问题将是一个巨大的挑战，需要对垃圾和废水处理设施进行投资，对已经被污染的区域要加强管制和清理。”

(Chinadaily.com.cn)