Pharmaceutical pollution of the world’s rivers

Abstract

Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world’s rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.

Concentrations of Ciprofloxacin in the World’s Rivers Are Associated With the Prevalence of Fluoroquinolone Resistance in E. coli: A Global Ecological Analysis

“…Wilkinson et al used a standard collection and assay to measure the concentration of a number of pharmaceutical agents including ciprofloxacin at 1,052 locations on 258 of the world's rivers in 104 countries [6]. In brief, between February 2018 and January 2020, they mailed a standard collection kit to collaborators in 104 countries and asked them to follow a standard sample collection protocol.…”

“…A relatively unexplored pathway towards AMR in gram-negatives is antimicrobial exposure in ambient water bodies [6,7]. A number of studies have found that extremely low concentrations of antimicrobials can select for de-novo AMR and enrichment of resistant versus susceptible strains in a range of gram-negative bacteria including Escherichia coli [8][9][10].…”

“…The appreciation that the MSC is considerably lower than the MIC has lead experts to recommend that the maximum concentration of antimicrobials allowed in water should be approximately 10-to 100-fold lower than the lowest minimum inhibitory concentrations (MICs) of bacteria present in large datasets such as that of EUCAST [6,9]. Whilst a number of studies have found that high concentrations of antimicrobials in ambient water are associated with AMR in various bacterial species in the environment [7,12,13], few studies have found an association with AMR in bacteria present in humans.…”

“…In this study we assess if there is a country-level association between the prevalence of fluoroquinolone resistance in E. coli and the concentration of ciprofloxacin in river water. To do this, we make use of a recently published global survey of pharmaceuticals in the world's rivers that found high levels of ciprofloxacin at numerous sites [6]. This survey used a standard collection and assay to measure the concentrations of 61 active pharmaceutical ingredients at over one thousand locations on 258 of the world's rivers in 104 countries [6].…”

“…To do this, we make use of a recently published global survey of pharmaceuticals in the world's rivers that found high levels of ciprofloxacin at numerous sites [6]. This survey used a standard collection and assay to measure the concentrations of 61 active pharmaceutical ingredients at over one thousand locations on 258 of the world's rivers in 104 countries [6]. This included the quinolone antimicrobial ciprofloxacin.…”