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

Women of Distinction: 2018 Edition

That special time of year is almost upon us again, the chance to celebrate Hamilton’s Women of Distinction.  And like many years, the McMaster community is out in full force.  I’m not sure exactly what it is about our community that produces so many exceptional women but in many years McMaster women make up over half of all nominees and every single Young Woman of Distinction.  That is an achievement for which the McMaster community should be very, very proud.  I encourage you to read their biographies and hear their stories to find some great inspiration.  These women are smart, enthusiastic, energetic, exceptional and contribute to our community in so many unique ways.   For me, the best categories to read about are at the opposite end of the spectrum, the Life Time Achievement nominees and the Young Woman of Distinctions.  I am really not sure how anyone in either category can achieve so much.

2018 is a special year for our lab because Ushma Purohit is a nominee in the Young Woman of Distinction category.  Ushma has been a Wilson Tox Lab member since her 2nd year of university, when she asked me to supervise her in an experiential learning course.  She was keen to get into a lab and gain some hands on experience and excited to join a new area for our lab.  Ushma worked with another stellar undergraduate researcher, Abby Lee, to develop hydra as a model system to study the impacts of human pharmaceuticals on aquatic species.  Abby was completing her senior thesis, assessing the effects of chronic exposure of hydra to an anti-epileptic and an anti-depressant pharmaceutical.  Ushma learned how to prepare, stain, and count the different cell typess from hydra so we could identify whether there were changes in the proportions of cell types after exposure.  That research is now being written into a manuscript for publication.  I often point to this area of our research program to demonstrate how impactful undergraduate researchers can be.

Ushma has continued to volunteer and complete research course work in my lab and is now in her senior year.  She has gone from assisting others on research to running her own.  Her senior thesis research focuses on the anti-microbial compound triclosan and whether this impacts compound negatively impacts hydra biology.  She is a bright and independent researcher with a great future.  Yet, this is just the tip of the iceberg.  Beyond her classes and research, Ushma has been contributing to her communities at McMaster, in the larger city of Hamilton, and beyond.

So what does it take to be a Young Woman of Distinction?  Well let’s just list two of Ushma’s accomplishments outside of the lab.  Ushma founded the first Canadian chapter of the organization She’s the First, which champions education of girls in low-income countries.  The McMaster chapter has focused on raising funds and education campaigns including conferences, art showcases, recreational events, and awareness videos, to encourage the conversation around intersectional feminisim within the McMaster community. Within Hamilton, this club has hosted educational workshops at the local Native Women’s Centre on health, self-care and other topics and in Hamilton’s elementary schools to educate students on topics such as communication and the media, body image and bullying, and female leadership. Not so surprisingly, this club has won two awards within its first year; a McMaster Student Union award for the Best New Club of the Year and an award from the parent organization for Outstanding Achievement in Community Engagement.

Ushma is the current President of the UNICEF club at McMaster University, a club she has been active in for over 3 years.  It is one of the largest clubs on campus and raises funds to support the health and education of children and raise awareness of humanitarian issues within the McMaster community.  The McMaster UNICEF club sends over 100 volunteers to the Children’s International Learning Centre and supports education of young children through a variety of initiatives.

What has Ushma’s nomination meant to her?

“The experience of becoming a nominee for the Women of Distinction awards has been a lot more meaningful for me than I could have imagined. This nomination provided me with the opportunity to learn about and interact with some of the most driven, hard-working and talented women in Hamilton. As an individual who is currently at the advent of her career, experiences like this play a pivotal role in moulding my ambitions and aspirations for the future. Regardless of who wins the Young Woman of Distinction Award, I believe that as nominees, we have won an eye-opening experience that we will carry with us in the years to come.”

Feel inspired yet?  This isn’t a complete list of all she does, but just a couple of highlights of what this young woman of distinction has already accomplished.  Ushma is just one of 34 nominees for the 2018 YWCA Hamilton Women of Distinction awards.  Take a few minutes and read about who they are and what they do.  Regardless of who wins the awards, McMaster and Hamilton are the big winners here because these women are exceptional.

  1. Bring on the summer! Leave a reply
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