Occurrence, fate, removal efficiency and ecological risk of selected antibiotics in wastewater and surface water of some hospitals: A case study in Vietnam
This study evaluates the occurrence, removal efficiency, and ecological risks of quinolone, macrolide, and β-lactam antibiotics in Vietnamese hospital wastewater and surrounding surface waters, revealing high contamination levels, variable treatment performance with AAO+MBR being most effective, and significant ecological risks primarily driven by ciprofloxacin.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The Big Picture: The "Leaky Pipe" Problem
Imagine hospitals as giant kitchens where doctors cook up cures for sick people. To do this, they use powerful ingredients called antibiotics. However, just like a kitchen that doesn't have a perfect sink, hospitals often wash these unused or leftover antibiotics down the drain.
This study looked at four different "kitchens" (hospitals) in Vietnam to see how much antibiotic "soup" was leaking out into the local rivers and ponds, and whether the hospitals' "filters" (wastewater treatment systems) were good enough to catch the mess.
The Cast of Characters: The Antibiotics
The researchers didn't look at every single antibiotic in the world. They picked six specific ones that are like the "frequent flyers" of the hospital world:
- The Quinolones: Ciprofloxacin, Levofloxacin, and Moxifloxacin. (Think of these as the tough, stubborn stains that are hard to wash out).
- The Macrolides: Clarithromycin.
- The Beta-Lactams: Cephalexin and Amoxicillin. (These are like the "easy-to-dissolve" stains, but they are used so much they still show up).
The Investigation: What Did They Find?
1. The "Before" Picture (Raw Sewage)
When the researchers looked at the wastewater before it went through any treatment, it was a chemical cocktail.
- The Star Villain: Ciprofloxacin was the most abundant. It was everywhere, like the most common guest at a party. In some samples, it was found at very high levels (up to 5,041 ng/L).
- The Runner-Up: Cephalexin was also very common.
- The Quiet Ones: Amoxicillin and Clarithromycin were present but in much smaller amounts.
2. The "After" Picture (The Treatment Systems)
The hospitals used three different types of "filters" to clean the water. The researchers treated these systems like different types of vacuum cleaners:
- The Basic Vacuum (AAO): Two hospitals (H1 and H2) used a standard system called AAO (Anaerobic-Anoxic-Oxic).
- Result: It was okay, but not great. It only caught about 40% to 80% of the antibiotics. A lot of the "dirty water" still slipped through.
- The Vacuum with a Turbo Attachment (AAO + MBBR): One hospital (H3) added a Moving Bed Biofilm Reactor. This is like adding a special brush to the vacuum.
- Result: Much better! It caught over 90% of the antibiotics.
- The Super-Vacuum (AAO + MBR): The fourth hospital (H4) used a Membrane Bioreactor. This is the high-tech version, like a vacuum with a HEPA filter that catches even the tiniest dust.
- Result: This was the winner. It removed the most antibiotics, often catching 90%+ of the pollutants. In fact, for some antibiotics, the water coming out was so clean the machines couldn't even detect them anymore.
3. The "Outside" Picture (Surface Water)
After the water left the hospitals, it flowed into nearby ponds and canals.
- Even though the treatment systems helped, Ciprofloxacin and Cephalexin were still the most common guests in the local water.
- The water near the hospital with the "Super-Vacuum" (H4) was the cleanest.
- The water near the hospitals with the "Basic Vacuum" (H1 and H2) was the dirtiest.
The Danger Zone: The Ecological Risk Score
The researchers asked a scary question: "Is this water dangerous to the fish and algae living in it?"
They used a scoring system called the Risk Quotient (RQ):
- Score under 0.1: Safe (Low Risk).
- Score 0.1 to 1: Caution (Medium Risk).
- Score over 1: Danger! (High Risk).
The Verdict:
Every single spot they tested had a High Risk score (above 1).
- Ciprofloxacin was the main reason for the danger. It's like a heavy anchor dragging down the safety of the ecosystem.
- Levofloxacin was the second biggest troublemaker.
The Takeaway
This study is like a report card for hospitals in Vietnam regarding how they handle their antibiotic waste.
- The Problem: Hospitals are releasing antibiotics into the environment, and the "Basic Vacuum" systems aren't strong enough to stop them.
- The Solution: Upgrading to advanced systems (like the Membrane Bioreactor) works much better, acting like a super-filter that keeps the antibiotics inside the hospital instead of letting them leak into nature.
- The Warning: Because the current systems aren't catching everything, the local water is currently too risky for the tiny life living in it, primarily because of the stubborn Ciprofloxacin.
In short: The hospitals are trying to clean their water, but they need better filters to stop these invisible chemical guests from taking over the local ponds and rivers.
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