Aquatic Toxicology Research

Aquatic Toxicology

My applied research program encompasses the areas of environmental physiology, biochemical toxicology, and aquatic toxicology.  Our studies are integrative in nature and move from whole organismal to cellular and molecular responses, using a wide variety of techniques.  Much of our research is experimental, laboratory based studies but we also perform field based research using native or invasive species.  Our interest is in the study of aquatic vertebrates, primarily fish but also a strong interest in marine mammals.  Most recently, we have begun to use two aquatic invertebrates, hydra and the marine annelid Capitella tellata, for our toxicological studies.  In our fish studies, we use zebrafish and rainbow trout as our primary model species in the laboratory.  By nature, the research is comparative and integrative.

Impacts of Pharmaceuticals in the Aquatic Environment

Pharmaceuticals cause histological changes in zebrafish kidney

Much research has documented that human pharmaceuticals are present in our surface waters due to release with wastewater effluent.  The release of pharmaceuticals into the environment is a large concern because these compounds are designed with inherent biological activity and physiological pathways are highly conserved across vertebrates.  Thus, we expect that pharmaceuticals will have biological activity in aquatic vertebrates such as fish.  Our research has focused on four major pharmaceuticals consistently found in wastewater effluent and surface waters: acetaminophen (common analgesic), carbamazepine (anti-epileptic and mood stabilizer), gemfibrozil (lipid regulator), and venlafaxine (anti-depressant).  Using environmentally relevant concentrations and chronic exposures, we have exposed zebrafish to single pharmaceuticals, pharmaceutical mixtures and diluted wastewater effluent to assess reproductive, developmental, histological, transcriptomic and multi-generational impacts.  We are exploring whether the effects of exposure to these compounds are through their mechanism of action in humans. We use rainbow trout to determine the physiological implications of pharmaceutical exposure in fish.  We are currently developing the use of hydra to study the effects of pharmaceuticals on aquatic species.  This research uses a wide array of techniques from basic histology and enzyme immunoassays, to microarray and microinjection approaches.

Zebrafish sperm.  We are examining sperm morphology and swimming speed as relevant endpoints for male offspring after parental exposure to pharmaceuticals.

Endocrine Disrupters in Hamilton Harbour and the Great Lakes Region

Intersex Male; ovo-testis with both sperm (SZ) and different stages of oocytes (PN and VG)

Round goby are a benthic, territorial invasive species in the Great Lakes Basin. We are using gobies to study endocrine disrupters in Hamilton Harbour because they are one two species in Hamilton Harbour and Cootes Paradise with intersex, the presence of both egg and sperm in male testes. Our research has focused on understanding feminization (intersex or ovo-testis; feminized urogenital papilla, expression of egg related genes in males) of round gobies at sites with historical industrial pollutants, combined sewer overflow, and wastewater effluent discharge.  The complicated discharge at many of these sites makes it difficult to discern if the feminization of fish is related to steroids or other pharmaceuticals in the environment, as originally proposed, or due to historical PAH type contaminants. Round goby are ideal for this research because they do not have a wide range and thus its contaminant exposure will reflect local pollution.  We have developed a quantitative PCR method for monitoring vitellogenin gene expression in male gobies.  Vitellogenin, an egg yolk precursor protein, should not be expressed in males unless they have been exposed to a natural or xeno-estrogen. We hope to identify sites polluted with endocrine disrupters within Hamilton Harbour and the Great Lakes Region and determine what contaminants are causing the endocrine disruption.

Thermal and Multiple Stressor Effects on Whitefish

Developing Lake Whitefish Embryos

Lake and round whitefish are cold water adapted fish which spawn in late fall.  Embryos develop overwinter at low temperatures. We  study the effects of temperature alone, and in combination with other stressors, on developing whitefish.  This work is important to understand the impacts of once through cooling, a common process used in many industrial processes including power plants.  This research is also important for understanding effluent impacts on Canadian receiving waters because many effluent discharges are warmer than ambient water.  We are examining both the direct effects on development, including morphology, survival, and hatching, as well as the longer term implications of embryonic exposures for juvenile fish. Our research will help us to understand the impacts of temperature on the development of an important native fish in the Great Lakes region.

Want to see a great video explaining our whitefish project?  Caitlin, an undergraduate in the lab in 2016-2017 academic year, won best video in the iClimate Video Competition.  Check out her video here!

This research has been funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) Strategic Project and Collaborative Research and Development Programs, the Canadian Water Network (CWN), Ontario Ministry of Research and Innovation Early Researcher Award program, and industrial partners.

Recent Posts

Recruitment begins

I’m not sure I can adequately describe the size or scale of the impact in our lab over the last year+ but this pandemic was dishing things out left, right and centre.  I feel like we are at a nexus of where the pandemic really delayed and harmed our research program.  The personal impacts for many in my group have likewise been large and the largest goal was to try to keep all of us upright, in science, and keeping our heads above the water.  In that regard, we need to reassess and redefine success over the last year.  We have survived (!!) and this was largely from the resilience of our group, as much as I think that is an overused term.  But we did get through this year together, pivoting efforts, helping each other, focusing on what we could do, taking things one step at a time.  Now we are starting to see progress in projects again and productivity is starting to leap back up.  That provides some space to look forward and plan for the future.  Let’s start with some lab success stories.  I’ll add in where we will be recruiting in the upcoming year in these projects.  A detailed outline of our open positions in 2021-2022 will be posted, so please check them out and get in touch if you are interested in our research program.

When the pandemic shut down McMaster, yellow perch were spawning and we were about to launch into working with a brand new species.  Waiting a full 12 months to restart was very hard but spring 2021 saw us undertaking the experiments we canceled the year before (and then some!) with very good outcomes.  The lab (especially Shamaila Fraz) came roaring back with ambitious plans that were very fruitful and lots of experiences in testing new protocols to help move research plans forward.  I am quite excited to see the data collection from our new samples and the analyses from the data already collected.  It will shape the direction of our research into developmental plasticity and impacts of temperature on fish development.  Much of our work this year focused on embryogenesis and immediate post-hatching periods while we work on the juvenile rearing stages. Perch are definitely a bit tough to rear post-hatching, compared to the other species we have worked on.  No surprise but we certainly learned some things not to do to keep them happy.  We are looking to recruit for this project in the upcoming months so we are ready to take on spring 2022 spawn.

While we graduated two graduate students from the lab in 2021, clear success stories, these were students who were done data collection prior to university shut down.  Other graduate students in the lab faced much bigger challenges. With major lost experiments and one totally new project later, we forged a new plan to get back on track. I’m really excited about these new directions.  Andrea Murillo has a freezer full of samples taken from our culture of the marine polychaete worm, Capitella teleta, and she is now extracting those samples to get geared up for gene expression and steroid hormone analyses.  Shemar Williams has completed a suite of experiments in zebrafish embryos and on track to finish his MSc.  Its great to see these project humming along.  This also means it is time to think about new graduate students in 2022 interested in the function of cytochrome P450 enzymes using either zebrafish or Capitella as a primary species of interest.

Success, of course, has also been obvious in more traditional ways. We have been so happy to celebrate Oana Birceanu’s success this year as she starts her new role at Western’s Physiology and Pharmacology department as an Assistant Professor. I look forward to continued collaboration and engagement with her research group in the years to come.

**  If you are interested in our lab, please check back under “Recruitment Opportunities” for more details in the upcoming days. I will be posting specific information there.  The much needed refresh of the lab website is just beginning.

 

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