Environmental Persistence of Pharmaceuticals: Pseudo-Persistence, Pathways, and Mitigation
Table of Contents
Introduction
Traces of pharmaceuticals are increasingly detected in environmental compartments such as surface water, groundwater, and marine ecosystems due to continuous human and veterinary use and incomplete removal in wastewater treatment systems. These compounds enter the environment through various pathways including domestic sewage, hospital effluents, agricultural runoff, and improper disposal of medicines.
The presence of pharmaceuticals in the environment is an important public health and ecological concern, as many of these compounds remain biologically active even at low concentrations. Among their various detrimental consequences, these compounds can significantly affect non-target aquatic organisms, causing alterations in behavior, reproduction, growth, and endocrine function, contributing to ecological imbalance and biodiversity loss. This could potentially lead to long-term risks for human health through water contamination and bioaccumulation.
Figure 1 — Main Pathways of Pharmaceutical Entry into the Environment
Domestic Sewage
Human excretion & household disposal
Hospital Effluents
High-concentration clinical waste streams
Agricultural Runoff
Veterinary drug residues in soil & water
Improper Disposal
Flushing or landfilling unused medicines
Industrial Effluents
Pharmaceutical manufacturing discharge
Understanding Pseudo-Persistence
2.1 — Definition and Key Characteristics
Pseudo-persistence is a term used to describe substances that remain present in the environment because they are constantly being released, even if they can break down over time. Unlike persistent pollutants, which resist degradation for long periods, pseudo-persistent contaminants stay in the environment due to continuous input rather than chemical stability.
It is also important to distinguish pseudo-persistence from bioaccumulation. Although these concepts are different, they are interconnected — sustained environmental concentrations from continuous discharge increase the likelihood of bioaccumulation in aquatic organisms.
Pseudo-Persistent
Can degrade, but continuous release keeps concentrations stable. Pharmaceuticals are the classic example.
Truly Persistent
Chemically stable, resists degradation over long periods. DDT, PCBs are well-known examples.
2.2 — Sources and Pathways of Entry
One of the main reasons pharmaceuticals remain in the environment is the inefficient removal of drug residues through wastewater treatment plants. As a result, small amounts of pharmaceuticals can enter natural water systems. Additional factors include increasing medication use, veterinary drug use, and incorrect disposal practices such as flushing medicines down sinks or toilets.
2.3 — Environmental Occurrence and Effects
Diclofenac and ciprofloxacin are common examples of pseudo-persistent pharmaceuticals. These compounds are often detected in surface waters due to their extensive use and inefficient removal during wastewater treatment. Research has shown that their presence may contribute to antimicrobial resistance, alter microbial communities, and affect aquatic organisms. Even at low concentrations, these compounds can influence reproduction, growth, and behavior in fish and other species.
Figure 2 — Effects on Aquatic Ecosystems
Fish & Aquatic Organisms
Altered behavior, impaired reproduction, disrupted endocrine function, stunted growth
Microbial Communities
Altered microbiome composition, promotion of antimicrobial resistance genes
Ecosystem Balance
Biodiversity loss, trophic disruption, bioaccumulation up the food chain
Human Health (Indirect)
Exposure via drinking water & food chain; EE2 hormonal effects; antimicrobial resistance spread
2.4 — Implications for Human Health
The effects of pseudo-persistent pharmaceuticals are not limited to aquatic ecosystems. Pharmaceutical residues can remain detectable in water systems and may contribute to long-term exposure through drinking water and the food chain. This is particularly relevant for biologically active compounds such as 17α-ethinylestradiol (EE2), which has been detected in aquatic environments and may affect hormonal processes. In addition, environmental antibiotics may contribute to the development and spread of antimicrobial resistance, creating challenges for future infection treatment.
Key concern: The long-term effects of exposure to mixtures of pharmaceutical residues remain uncertain and require further research. Synergistic interactions between compounds may amplify harm beyond what individual substances suggest.
Regulatory Frameworks and Mitigation Strategies
3.1 — European Union Framework
The European Union adopts a comprehensive approach based on chemical risk assessment, source reduction, environmental monitoring, and regular updates to regulatory frameworks. The current focus is on early identification of emerging contaminants and the limitation of their release into the environment.
3.2 — Turkey: Progress and Challenges
Turkey is progressing through international commitments such as the Stockholm Convention, while also aligning its environmental policies with EU standards and strengthening national implementation plans and institutional capacity. Current priorities include improving monitoring infrastructure, identifying contaminated sites, and implementing technical remediation projects.
Figure 3 — EU vs. Turkey Regulatory Comparison
| Aspect | 🇪🇺 European Union | 🇹🇷 Turkey |
|---|---|---|
| Approach | Comprehensive risk-based framework | International alignment, growing capacity |
| Monitoring | Advanced, early contaminant detection | Infrastructure being strengthened |
| Priority | Emerging contaminant limitation | Site identification & remediation |
3.3 — Technological Approaches
Effective management of pseudo-persistent pollutants requires not only strong regulatory control and institutional coordination, but also advances in treatment technology. Both regulatory contexts are expected to place greater emphasis on broader chemical screening systems, environmentally friendly treatment technologies, and pilot-scale applications.
In particular, the development of biodegradable, recoverable, or magnetic nanocomposite materials — which can be retrieved from water after use — may offer promising solutions for the sustainable removal of pseudo-persistent pollutants. Integrated strategies combining policy measures and technological innovation will therefore be essential.
Figure 4 — Emerging Technological Solutions
Magnetic Nanocomposites
Retrievable materials that adsorb pharmaceutical residues from water bodies
Advanced Oxidation
Ozone and UV-based processes that degrade pharmaceutical molecules
Biodegradable Materials
Eco-friendly sorbents that break down after capturing contaminants
Chemical Screening
Broad-spectrum monitoring tools for early detection of emerging contaminants
Conclusion
Pharmaceutical residues represent an increasingly serious environmental concern, as they are continuously released into ecosystems and can remain biologically active even at very low concentrations. Many of these compounds exhibit pseudo-persistence, resulting in a broad and sustained presence in surface waters and other environmental compartments.
This situation poses significant risks for aquatic organisms, including disturbances in reproduction, growth, and microbial balance, as well as the potential emergence of antimicrobial resistance.
Addressing this challenge requires stronger regulatory frameworks, improved wastewater treatment technologies, and more responsible use and disposal of pharmaceuticals. Meaningful progress will depend on coordinated action that integrates policy measures with innovative treatment solutions — creating a sustained, long-term reduction in the environmental burden of pharmaceutical contaminants.
Key Takeaways
Pharmaceuticals are pseudo-persistent — they degrade, but continuous release maintains environmental concentrations.
Aquatic ecosystems bear the greatest burden — from fish behavior to microbial resistance.
Regulatory approaches differ — the EU leads with comprehensive frameworks while Turkey is actively developing its capacity.
Technological innovation — especially magnetic nanocomposites and advanced oxidation — offers promising mitigation pathways.
References
Ashfield, N., Li, J., Bouzas-Monroy, A., & Boxall, A. B. A. (2025). Silent side effects: Pharmaceuticals as contaminants of emerging concern. Annual Review of Environment and Resources, 50, 273–301.
Caban, M., & Stepnowski, P. (2021). How to decrease pharmaceuticals in the environment? A review. Environmental Chemistry Letters, 19, 3115–3138.
Eapen, J. V., Thomas, S., Antony, S., George, P., & Antony, J. (2024). A review of the effects of pharmaceutical pollutants on humans and aquatic ecosystem. Exploration of Drug Science, 2, 484–507.
Ghezzi, P. (2019). Environmental risk of pharmaceuticals: An underestimated problem in public health. International Journal of Environmental Research and Public Health, 16(19), Article 3662.
Guettai, N., Kadmi, Y., Puri, M., Kerkich, K., & Bouargane, B. (2024). Occurrence, analysis and removal processes of emerging pharmaceuticals from waters. Journal of Cleaner Production, 466, Article 142654.
Korkmaz, N. E., Savun-Hekimoğlu, B., Aksu, A., Burak, S., & Caglar, N. B. (2022). Occurrence, sources and environmental risk assessment of pharmaceuticals in the Sea of Marmara, Turkey. Science of the Total Environment, 819, Article 152996.
O'Flynn, D., Lawler, J., Yusuf, A., et al. (2021). A review of pharmaceutical occurrence and pathways in the aquatic environment. Analytical Methods, 13(5), 575–594.
Pal, P. (2018). Treatment and disposal of pharmaceutical wastewater: Toward the sustainable strategy. Separation & Purification Reviews, 47(3), 179–198.
Patel, M., Kumar, R., Kishor, K., et al. (2019). Pharmaceuticals of emerging concern in aquatic systems. Chemical Reviews, 119(6), 3510–3673.
Beek, T., Weber, F. A., Bergmann, A., et al. (2016). Pharmaceuticals in the environment — Global occurrences and perspectives. Environmental Toxicology and Chemistry, 35(4), 823–835.
Yılmaz, İ., Koca, M., & Demir, V. (2024). Marine pollution and pharmaceutical contaminants. Journal of Marine Science and Engineering, 12(7), Article 1133.