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Q & A:
Dr. Karen Kidd, University of New Brunswick

Drugs leaking into waterways bad news for fish
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Interview by Lori Valigra

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.

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.

For more information contact Karen Kidd at kiddk@unbsj.ca or visit the Canadian Rivers Institute Web site at www.unb.ca/cri/.

2005 The Gulf of Maine Times