In Asia, researchers found that antibiotic residues in wastewater and wastewater treatment plants risk contributing to antibiotic resistance, and the drinking water may pose a threat to human health. Published in The Lancet Planetary Health, their comprehensive analysis also determined the relative contribution of various sources of antibiotic contamination in waterways, such as hospitals, municipals, livestock, and pharmaceutical manufacturing.
“Our results can help decision-makers to target risk reduction measures against environmental residues of priority antibiotics and in high-risk sites, to protect human health and the environment,” says first author Nada Hanna, researcher at the Department of Global Public Health at Karolinska Institutet. “Allocating these resources efficiently is especially vital for resource-poor countries that produce large amounts of antibiotics.”
Antibiotics can enter the environment during their production, consumption and disposal. Antibiotic residues in the environment, such as in wastewater and drinking water, can contribute to the emergence and spread of resistance.
Major antibiotics producers and users
The researchers looked for levels of antibiotic residues that are likely to contribute to antibiotic resistance from different aquatic sources in the Western Pacific Region (WPR) and the South-East Asia Region (SEAR), regions as defined by the World Health Organization. China and India, among the world’s largest producers and consumers of antibiotics, fall within these regions.
To find the data, researchers made a systematic review of the literature published between 2006 and 2019, including 218 relevant reports from the WPR and 22 from the SEAR. They also employed a method called Probabilistic Environmental Hazard Assessment to determine where the concentration of antibiotics is high enough to likely contribute to antibiotic resistance.
Ninety-two antibiotics were detected in the WPR, and forty five in the SEAR. Antibiotic concentrations exceeding the level considered safe for resistance development (Predicted No Effect Concentrations, PNECs) were observed in wastewater, influents and effluents of wastewater treatment plants and in receiving aquatic environments. Wastewater and influent of wastewater treatment plants had the highest risks. The relative impact of various contributors, such as hospital, municipal, livestock, and pharmaceutical manufacturing was also determined.
Potential threat to human health
In receiving aquatic environments, the highest likelihood of levels exceeding the threshold considered safe for resistance development was observed for the antibiotic ciprofloxacin in drinking water in China and the WPR.
“Antibiotic residues in wastewater and wastewater treatment plants may serve as hot spots for the development of antibiotic resistance in these regions and pose a potential threat to human health through exposure to different sources of water, including drinking water,” says Nada Hanna.
Limitations to be considered when interpreting the results are the lack of data on the environmental occurrence of antibiotics from many of the countries in the regions and the fact that only studies written in English were included.
Source: Karolinska Institutet
