Cuttack: Chemical residues released from pharmaceutical and personal care products are not only becoming a major contaminant of water bodies in urban areas but are also becoming a source of drug resistance in the environment, a new study has warned.
The study, which evaluated vulnerability and resilience of urban water bodies in Guwahati city, found the presence of viruses and multidrug resistant Escherichia coli in samples collected from the Brahmaputra. Deepor Beel, a freshwater wetland,- was found to be the least polluted in comparison to the Brahmaputra river and Bharalu, the tributary turned urban drain.
Researchers analysed occurrence of pharmaceuticals and personal care products, intestine occurring virus, antibiotic resistant bacteria, metal, faecal contamination and antibiotic resistance genes, as well as the long term changes in precipitation and temperature of water. Some microbes displayed 100% resistance to major antibiotics, such as levofloxacin, ciprofloxacin, norfloxacin, kanamycin monosulphate and sulfamethoxazole.
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“The Brahmaputra due its high diluting capacity through enormous discharge is providing resilience to urban water and all the pollution added by the city drains gets diluted in the downstream,” Manish Kumar, a researcher at IIT Gandhinagar who led the study, told India Science Wire. His team included scientists from Sri Lanka and Japan as well.
They collected water samples from the Brahmaputra before it entered the city as well as before its water mixed with Bharalu. They collected another set of samples after the water mixed downstream, and then from a location 10 kilometres downstream of Guwahati. Finally, they picked up three more samples upstream from the confluence point of Bharalu.
They found that the concentration of pharmaceutical and personal care products were high in drain samples and very low in lake and river water. Researchers said it was clear that pharmaceutical and personal care product residues were directly associated with raw sewage and hence not detected in upstream or downstream of the Brahmaputra, or in the Deepor Beel wetland.
The study further reports contamination of drain water by toxic metals like arsenic, cobalt and manganese correlates with water quality parameters such as acidity and appear to be inducing antibiotic resistance in E. coli bacteria.
“As there are not much new antibiotics discovered all over the world, the existence of superbug, resistant to several antibiotics is alarming,” Ryo Honda, a member of the team from Japan’s Kanazawa University, said. Tushara Chaminda, the researcher from Sri Lanka’s University of Ruhuna, added, “Hundred percent resistances for all six antibiotics that we have tested is the result – [which] we never expected.”
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Scientists, policymakers and medical practitioners must act to control the use and disposal of antibiotics. “It is time to adopt a holistic approach for vulnerability and resilience evaluation of water systems and to revise the ambient water quality guidelines by including new age parameters”, added Manish Kumar.
This work was funded under the India-Japan Cooperative Science Programme of the Department of Science and Technology. The results of the study have been published in the journal Science of the Total Environment.
Sanghamitra Deobhanj writes for India Science Wire and tweets at @CtcSangham.