Right now, roughly 8,500 tons of antibiotic residues are washing through the global river system annually, with over 3,300 tons ultimately reaching oceans and lakes. This discovery comes from a new study from McGill University that examined how antibiotics from human consumption alone, not including veterinary or industrial sources, are contaminating waterways worldwide.
The study, published in PNAS Nexus, revealed that over 6 million kilometers of rivers contain antibiotic concentrations exceeding thresholds considered safe for ecosystems and for preventing antimicrobial resistance during low water flow periods. The problem is particularly severe in Southeast Asia, where rivers show the highest concentrations of these compounds.
What’s Hiding in our Waterways?
This invisible pollution threatens not just aquatic life but potentially human health as well. Even in small amounts, antibiotics can reduce microbial diversity in water systems, increase resistance genes, and harm fish and algae. The World Health Organization has already recognized antimicrobial resistance as a critical global threat, with projections suggesting resistant bacterial infections could become the leading cause of global deaths by 2050.
After we consume antibiotics, our bodies don’t fully metabolize them. The remainder gets excreted and enters wastewater systems that often aren’t designed to remove these compounds effectively. In fact, nearly half of the world’s wastewater is released without any treatment at all.
The researchers tracked the journey of the 40 most commonly used antibiotics as they moved from human consumption through sewage systems and into waterways. Their analysis revealed that 29% of consumed antibiotics eventually reach river systems, while 11% make it all the way to oceans or inland water bodies like lakes.
Three Major Antibiotics Dominate River Pollution
Three antibiotics in particular—amoxicillin, ceftriaxone, and cefixime—were found to be the dominant pollutants. Amoxicillin alone accounts for 45% of at-risk river length. This common antibiotic, which makes up 75% of total global antibiotic consumption according to the researchers, is often available without prescription in many countries, contributing to its widespread presence in waterways.
The problem is expected to worsen as global antibiotic consumption increases, especially in low- and middle-income countries. Between 2000 and 2015, global antibiotic consumption jumped by 65%, with low-income countries seeing a staggering 114% increase. Projections suggest consumption will rise another 200% by 2030.
The research team stresses that with rising antibiotic usage worldwide, particularly in developing regions, there’s an urgent need to develop and implement strategies that reduce antibiotic pollution to protect both environmental and human health.
Countries with the highest risk include India, Iran, Nigeria, Ethiopia, Turkey, Vietnam, and Pakistan—each with more than 80% of their river lengths showing high or very high antibiotic concentrations. In India and Pakistan specifically, more than 30% of rivers are impacted by at least 10 different antibiotics at concentrations exceeding high-risk thresholds.
10 Percent Of World At Risk
The study estimates that 750 million people, approximately 10% of the global population, live within 10 kilometers of rivers with the highest cumulative concentrations of antibiotics. If these waters are used for drinking, these populations could potentially be exposed to chronic antibiotic intake at harmful levels.
The researchers calculated that in rivers with the highest concentrations, drinking water directly from these sources would expose people to antibiotics at levels that exceed acceptable daily intake thresholds for 16 out of 30 antibiotics examined. While most developed countries have water treatment systems, these aren’t typically designed to remove antibiotics effectively.
This study only looked at antibiotics from human consumption. The actual situation is likely much worse when considering veterinary use, which is approximately twice the human consumption level globally, as well as pharmaceutical manufacturing waste and aquaculture.
Climate change and increased water usage will likely exacerbate the problem by causing more extreme low-flow conditions in rivers, which will further concentrate antibiotics and other pollutants in waterways.
The researchers call for urgent action, including expanding access to wastewater treatment, upgrading existing treatment facilities to better remove antibiotics, improving healthcare practices to ensure appropriate antibiotic use, and enhancing regulatory guidelines with a focus on high-risk substances and locations.
Source : https://studyfinds.org/750-million-people-water-laced-with-antibiotics/