Drugs leaking into waterways bad news for fish
Q & A:
Dr. Karen Kidd, University of New Brunswick
Printer Friendly Page
Interview by Lori Valigra
She received her Ph.D. from the University of Alberta in 1996, and began her career investigating
pollution in fisheries in the Yukon, Eastern Arctic and East Africa. This work focused on pesticides
and other persistent pollutants that concentrate and get into food webs. She also is conducting
several studies in Atlantic Canada on the accumulation of mercury in freshwater food webs. Kidd
is concerned that these kinds of pollutants are getting into fish and accumulating to high levels
that may cause health effects for humans or fish-eating wildlife. In addition, she also studies
the impact of pollution, including pharmaceuticals in sewage outfall, on fish. The Gulf of Maine
Times recently interviewed Kidd about her work on how pharmaceutical and other pollutants impact
wildlife, focusing on the effects of the female hormone estrogen on fish.
Q: You've studied the impacts of pharmaceuticals on fish in western Canada. Are you finding similar
problems in eastern Canada?
A: The reason I moved to New Brunswick is to work with the CRI and to address some of these issues
in Atlantic Canada. There hasn't been a lot done on the effects of pharmaceuticals and personal
care products on river health in this part of the country. The big focus of my research with the
Canadian federal government was doing a whole lake synthetic estrogen addition experiment.
The reason why we got into that work is that in Britain they were seeing that a lot of the male
fish downstream of sewage treatment plants were becoming feminized. These fish were producing egg
proteins, and they were developing eggs in the more serious cases, because they were being exposed
to estrogens in the water. That work was done in the early to mid-1990s, but there have been a number
of studies since then in the United States and Canada that show that estrogens are having similar
impacts on fish here. A number of small-bodied fish species, like the fathead minnow, respond quite
dramatically to estrogens.
Q: What is the source of the estrogens?
A: Pharmaceutical companies are aware of potential problems their products would cause in the
aquatic environment, so they're conscientious about disposing of their waste products. Most of
what's getting into the environment is from humans excreting these drugs or disposing of them by
flushing them down the toilet. Women excrete both natural estrogens and the synthetic estrogens
used in birth control pills; these estrogens are finding their way into the waterways downstream
of wastewater treatment plants. Seventy-five percent or more of these estrogens can be broken down
or degraded in the sewage treatment plant process. But there are still enough of these natural and
synthetic estrogens getting into some rivers for male fish to become feminized.
Q: Where is this happening?
A: In Canada, most of the studies have been done in Ontario and in British Columbia, and there's
been a bit of work in Alberta, Manitoba and Saskatchewan. And in the United States there's been a
fair amount of work done in a number of states including Colorado, Florida, Texas and Minnesota
looking for feminized male fish and for the presence of estrogens in rivers. But in Atlantic
Canada it hasn't been well studied. We certainly have several rivers that are receiving sewage
effluents, and in some cases untreated sewage, so there's potential for the fish to be impacted by
estrogens. The city of Saint John is one example where there is untreated sewage going into streams
that are flowing into the Bay of Fundy. This sewage is coming from individual households.
Q: How close do the fish have to be to the source to be impacted?
A: The closer one is to the outfall of the sewage treatment plant, the higher the concentrations are.
And concentrations will change over a season or over a year depending on how much rainfall there
has been and on how much sewage is in the river flow. The synthetic estrogen that's used in birth
control pills is very potent and can impact males at levels below one nanogram per liter, or one
part per trillion. And the fish don't have to be exposed for very long. Sometimes a few weeks is
enough to impact whether an egg develops into a female or a male, to cause a male fish to start
producing egg proteins or to impact the survival of young fish or their sexual development. In
mature male fish it may take longer, sometimes months, for them to start developing eggs.
Q: Does it matter that it's human estrogen?
A: No, because the hormones we use to reproduce are very similar to the hormones fish use to
reproduce.
Q: In the northeastern part of North America, what kind of fish would be most susceptible to this
type of exposure?
A: Every fish species reacts differently to chemicals. We tend to see more impacts in the fish that
live in a small area. They may live just downstream of the sewage outfall and be exposed to more
of these estrogens than a fish that would move up and down the river and in and out of the sewage
outfall. But every fish will be affected by estrogen if they are exposed to enough of it. Some of
the stationary fish include the freshwater fathead minnow and slimy sculpin and estuarine species
like mummichogs.
Q: What measures can be taken to reduce the estrogens that get through treatment systems?
A: There have been some studies showing that the more you treat the wastewater, and the longer the
water is in the treatment plant, the more estrogens you remove. Primary treatment of sewage removes
less than five percent of the estrogens, but secondary treatment will remove from 75 to 98 percent
of them. This range seems to depend on how long the wastewater is treated and whether there is
treatment such as nitrification of the wastewaters. The key to removing estrogens or reducing their
impact is to treat sewage - we still have cities that discharge raw sewage - and to use secondary
treatment of the wastewater at a minimum. Bacteria in the sewage treatment process can break down
estrogens. These hormones also can bind to particles and settle out of the wastewater.
Q: What are some of the other drugs that can be harmful?
A: One example is Prozac. Researchers at Baylor University in the United States have found that the
active ingredient in Prozac, fluoxetine, is accumulating in fish muscle. They've also shown in lab
studies that fluoxetine impacts fish reproduction and fish behavior. To date, we have found more
than 50 different drugs in sewage effluents and in surface waters, and as technology improves, we're
going to find more drugs in the environment. We know that thousands of different pharmaceuticals are
used for human health. Some, like the painkiller ibuprofen, are effectively degraded by sewage
treatment processes. Others like fluoxetine are more resistant to degradation, so they're going
to get into the environment.
Q: Are there impacts from antimicrobial and other soaps and household products, detergents or
chemicals?
A: Oh my goodness, yes. Sewage effluents contain many different chemicals, including detergents,
pesticides, metals and cosmetics, so the rivers receiving these sewage effluents are really getting
a complicated mixture of chemicals. One of the big things we don't know and that is very difficult
to determine is what in these mixtures is having an impact on the fish, because they're getting
exposed to surfactants (a primary ingredient in detergents), fragrances and a number of
pharmaceuticals and other household products that can accumulate and cause problems. There
are chemicals used in detergents that can interfere with reproduction with fish as well, but
they tend to be much less potent than something like an estrogen, because fish naturally use
estrogens to control their reproduction.
Q: Please describe some of the programs on the Saint John River.
A: The Saint John River is one of our big focuses with the Canadian Rivers Institute, because
it's the most heavily impacted river in New Brunswick due to industrial, municipal and agricultural
activities in the watershed. We've had a number of projects looking at fish health and abundance
in the upper parts of the river into Maine and then in reaches of river between Edmundston and
Fredericton in New Brunswick. We're starting to do more studies in the mouth of the river near
the Bay of Fundy because very little is known about fish health in that area and because there
are raw sewage discharges into that region. I am conducting studies to determine whether sewage
is affecting fish health and whether some of the pharmaceuticals and personal care products in
the outfall accumulate in fish tissues.
© 2005 The Gulf of Maine Times
KAREN KIDD'S dedication to studying how pharmaceutical and household pollutants get into freshwater
systems and impact wildlife brought her to the University of New Brunswick and the college's Canadian
Rivers Institute (CRI) a year ago. As the Canada Research Chair in Chemical Contamination of Food Webs
and an associate professor, Kidd and her colleagues have started research on the Saint John River,
and expect some early results next spring or summer. Prior to that she was a research scientist with
the federal government's Fisheries and Oceans Canada.
For more information contact Karen Kidd at kiddk@unbsj.ca or visit
the Canadian Rivers Institute Web site at www.unb.ca/cri/.