Up to 90% of consumed drugs enter the environment. This may have negative effects on wildlife, especially when the drugs take long periods to break down. This study assessed the breakdown of sulphonamides — a class of antibacterials — in samples from two rivers in Poland. The results showed that sulphamethoxazole, a common veterinary antibiotic, was the most persistent and that various factors inhibit degradation, including low temperatures, heavy metal pollution and low pH.
- Biodegradation rate of sulfonamides (SNs) in river water is variable.
- Biodegradability of SNs depends on the growing season.
- High concentration of salts in river water inhibits the SNs biodegradation.
- Sulfamethoxazole could be classified as Persistent Organic Pollutant (POP).
Which factors make drugs persistent? A look at sulphonamides in Polish rivers, Science for Environment Policy, 12 January 2017.
Assessment of the biodegradability of selected sulfa drugs in two polluted rivers in Poland: Effects of seasonal variations, accidental contamination, turbidity and salinity, science direct, August 2016.
Image credit Janusz Nowak.
The aim of our study was to assess the aerobic biodegradation of four selected sulfonamides (sulfanilamide, sulfamethoxazole, sulfadiazine and sulfathiazole) using water samples drawn from highly polluted rivers. Additionally, we aimed to identify the factors that have a significant effect on the process efficiency.
The 19 water samples were collected from Brynica and Czarna Przemsza rivers (in Poland) at the same location at approximately monthly intervals. A characteristic feature of the results is the presence of significant differences between the rates of sulfonamides biodegradation in particular samples.
The sulfonamide most resistant to biodegradation was sulfamethoxazole, whereas sulfathiazole was most biodegradable. Seasonal variations and related microbial population changes had the most significant effects on sulfonamides biodegradation, e.g., the studied process was highly inhibited during wintertime. A decrease in the biodegradation rate in the river water could be caused by an accidental water pollution by industrial wastewater with heavy metals, an increase in salinity and a decrease in pH, and turbidity.