Oxolinic acid in aquaculture waters: Can natural attenuation through photodegradation decrease its concentration?
Vitória Loureiro Dos Louros1, Carla Patrícia Silva2, Helena Nadais3
1CESAM & Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; CESAM & Department of Environment and Planning, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
The Science of the Total Environment
|December 29, 2020
Summary
Oxolinic acid (OXA), an aquaculture antimicrobial, degrades slower in natural waters due to dissolved organic matter and salinity. Singlet oxygen significantly influences OXA photodegradation in aquatic environments.
Area of Science:
- Environmental Chemistry
- Aquatic Toxicology
- Pharmaceutical Science
Background:
- Quinolones, like oxolinic acid (OXA), are prevalent antimicrobials in aquaculture.
- Their presence in aquatic environments necessitates understanding their environmental fate.
- Photodegradation is a key attenuation process for antibiotics resistant to microbial breakdown.
Purpose of the Study:
- To investigate the photodegradation of oxolinic acid (OXA) in various aquatic matrices.
- To assess the influence of environmental factors like dissolved organic matter and salinity on OXA photodegradation rates.
- To elucidate the role of reactive oxygen species, specifically singlet oxygen, in OXA photodegradation.
Main Methods:
- Photodegradation experiments were conducted in ultrapure water, freshwater, and brackish water.
- The impact of dissolved organic matter (DOM) and salinity (NaCl, synthetic sea salts) was evaluated.
- Experiments utilizing a singlet oxygen scavenger were performed under solar radiation.
Main Results:
- Photodegradation rate constants decreased from ultrapure water (0.70 h⁻¹) to freshwater (0.42 h⁻¹) and brackish water (0.172 h⁻¹).
- Dissolved organic matter (DOM) contributed to reduced OXA photodegradation in freshwater.
- High salinity significantly inhibited OXA photodegradation, with singlet oxygen identified as a key reactive species.
Conclusions:
- Environmental factors, particularly salinity and DOM, significantly reduce the photodegradation rate of oxolinic acid (OXA) in aquaculture-impacted waters.
- Singlet oxygen plays a crucial role in the photodegradation of OXA.
- These findings are vital for accurate environmental risk assessments of OXA in aquatic ecosystems.
Related Concept Videos
00:46Bioremediation
21.7K
Bioremediation is the use of prokaryotes, fungi, or plants to remove pollutants from the environment. This process has been used to remove harmful toxins in groundwater as a byproduct of agricultural run-off and also to clean up oil spills.
21.7K
01:17Oxidation of Phenols to Quinones
4.0K
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
4.0K
01:20Radical Autoxidation
2.7K
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
2.7K