Fish Downstream of Wastewater Plants Accumulate Drugs

Water Pollution Opioids and Other Drugs Accumulating in Freshwater Fish

2026-04-17 Source: University of Waterloo 2 min Reading Time

Related Vendors

Bimos - eine Marke der Interstuhl Büromöbel GmbH & Co. KG

Fish living downstream of wastewater treatment plants are accumulating antidepressants, opioids and other drugs of abuse in their bodies, according to a new study.

Researchers from the University of Waterloo collect fish from a freshwater stream to test them for the presence of opioids and antidepressants.(Source: University of Waterloo) — Researchers from the University of Waterloo collect fish from a freshwater stream to test them for the presence of opioids and antidepressants.
(Source: University of Waterloo)

Using a new analytical method they developed, a team of researchers from the University of Waterloo discovered that several substances that affect the central nervous system, including fentanyl, methadone and venlafaxine, were detected in small fish living in rivers that receive urban wastewater.

Previous research indicated that these substances have the potential to alter fish behaviour, development and reproduction, but this is the first time that scientists documented their distribution in wild fish in Canada. The findings improve our understanding of how this novel group of contaminants can enter and potentially accumulate in freshwater ecosystems, raising concerns about the potential for long-term effects.

Gallery

The novel method makes it possible to detect trace amounts of drugs of abuse in small fish.(Source: University of Waterloo)

The researchers detected fentanyl, methadone, venlafaxine, and O-desmethylvenlafaxine in all species collected, including the greenside darter.(Source: University of Waterloo)

“This research shows that fish are exposed to and can accumulate these novel drugs when exposed to even well-treated wastewater,” said Dr. Mark Servos, a professor in the Department of Biology and a researcher at the Water Institute. “Because wastewater treatment plants are not designed to remove pharmaceuticals, aquatic organisms are likely exposed to these chemicals downstream of most communities where these drugs are prescribed or used illicitly.”

Using their new method, the research team found that male fish accumulated higher concentrations of some substances than females. Biological factors, such as physiology and metabolism, may influence how contaminants accumulate in different organisms.

“This research demonstrates the importance of developing sensitive analytical methods for monitoring emerging contaminants and improving our ability to assess their potential for impacts on aquatic ecosystems,” said Dr. Diana Cárdenas-Soracá, a postdoctoral fellow in the Department of Biology at Waterloo. “Hopefully this work will highlight the need to continue to characterize the diversity of new chemicals potentially entering the environment.”

Future work will focus on understanding the factors that influence environmental exposure and what the bioaccumulation of these compounds means for fish health, including impacts on neurophysiology, behaviour, and reproduction.

The study Darters (Etheostoma spp.) as indicators of antidepressant and drug of abuse exposure in an urban watershed, appears in Environmental Pollution.

Original Article: Darters (Etheostoma spp.) as indicators of antidepressant and drug of abuse exposure in an urban watershed; Environmental Pollution; DOI:10.1016/j.envpol.2026.127918

(ID:50819883)

Subscribe to the newsletter now

Don't Miss out on Our Best Content

Business E-mail

Please enter a valid mailadress.

By clicking on „Subscribe to Newsletter“ I agree to the processing and use of my data according to the consent form (please expand for details) and accept the Terms of Use. For more information, please see our Privacy Policy. The consent declaration relates, among other things, to the sending of editorial newsletters by email and to data matching for marketing purposes with selected advertising partners (e.g., LinkedIn, Google, Meta)

Date: 08.12.2025

Naturally, we always handle your personal data responsibly. Any personal data we receive from you is processed in accordance with applicable data protection legislation. For detailed information please see our privacy policy.

Consent to the use of data for promotional purposes

I hereby consent to Vogel Communications Group GmbH & Co. KG, Max-Planck-Str. 7-9, 97082 Würzburg including any affiliated companies according to §§ 15 et seq. AktG (hereafter: Vogel Communications Group) using my e-mail address to send editorial newsletters. A list of all affiliated companies can be found here

Newsletter content may include all products and services of any companies mentioned above, including for example specialist journals and books, events and fairs as well as event-related products and services, print and digital media offers and services such as additional (editorial) newsletters, raffles, lead campaigns, market research both online and offline, specialist webportals and e-learning offers. In case my personal telephone number has also been collected, it may be used for offers of aforementioned products, for services of the companies mentioned above, and market research purposes.

Additionally, my consent also includes the processing of my email address and telephone number for data matching for marketing purposes with select advertising partners such as LinkedIn, Google, and Meta. For this, Vogel Communications Group may transmit said data in hashed form to the advertising partners who then use said data to determine whether I am also a member of the mentioned advertising partner portals. Vogel Communications Group uses this feature for the purposes of re-targeting (up-selling, cross-selling, and customer loyalty), generating so-called look-alike audiences for acquisition of new customers, and as basis for exclusion for on-going advertising campaigns. Further information can be found in section “data matching for marketing purposes”.

In case I access protected data on Internet portals of Vogel Communications Group including any affiliated companies according to §§ 15 et seq. AktG, I need to provide further data in order to register for the access to such content. In return for this free access to editorial content, my data may be used in accordance with this consent for the purposes stated here. This does not apply to data matching for marketing purposes.

Right of revocation

I understand that I can revoke my consent at will. My revocation does not change the lawfulness of data processing that was conducted based on my consent leading up to my revocation. One option to declare my revocation is to use the contact form found at https://contact.vogel.de. In case I no longer wish to receive certain newsletters, I have subscribed to, I can also click on the unsubscribe link included at the end of a newsletter. Further information regarding my right of revocation and the implementation of it as well as the consequences of my revocation can be found in the data protection declaration, section editorial newsletter.