London’s water sources rich in Antibiotic-resistant genes

London’s Global University- UCL has confirmed availability of high levels of antibiotic genes in Central London’s freshwater sources. Thames River recorded the highest level among other water resources such as Serpentine, Regent’s Canal, and in Regent’s Park Pond. Study confirms these water bodies contain genes which are resistant to bacteria common among antibiotics like erythromycin, tetracycline and penicillin.

Experts suggest the main source for such bacteria is the common human and animal waste. After consumption of antibiotics the drug is excreted into the sewer system before being flushed into other freshwater sources. It is due to the presence of such antibiotics that water bodies containing such resistant genes grow quicker than usual and are capable of sharing resistance with other microbes.

“This shows that more research is needed into the efficiency of different water treatment methods for antibiotic removal, as none of the treatments currently used were designed to incorporate this. This is particularly important in the case of water bodies into which we discharge our treated wastewater, which currently still contains antibiotics. It is also important to look into the levels of antibiotics and resistant bacteria in our drinking water sources,” according to Dr Lena Ciric, Project lead of UCL Civil, Environmental & Geomatic Engineering.

As reports suggest, presently there is no concrete legislation which can remove antibiotics or even resistant genes from the water sources. This fact also suggests that antibiotics and resistant genes could hence also be present in small quantities in drinking water sources, though this would require further testing.

River Thames is more prone to antibiotics and resistant genes, owning to large amount of wastewater treatment discharges into the river. Moreover, antibiotics that enter through the sewer system get diluted in the river through flushing and the low levels further augment the quantity of resistance genes and thus also spreads microbes.

For the study, the team also developed a DNA-based method which provides information on the number of resistant genes per litre of water. The number of resistant genes was then compared with the number from various sources of London’s water systems.

According to the report, the team is now engaged in withdrawing antibiotics and resistant bacteria and genes from London’s natural water system. For the measure, the team is also using slow sand filtration, a type of drinking water treatment.

Allegedly this technique is popular worldwide and is also used at Thames Water’s Coppermills Treatment Works in order to provide drinking water for most of the north east of London. Furthermore, the team is trying out various methods of filtration by changing proportions of sand and also by activating carbon at different flow rates.