Burkholder: ‘Many N.C. Reservoirs & Estuaries are Degraded’
10/25/11 by Juanita Teschner
Dr. JoAnn Burkholder, director of the Center for Applied Aquatic Ecology and William Neal Reynolds Distinguished Professor at N.C. State University, spoke Oct. 20 at the annual meeting of the Yadkin Riverkeepers at Catawba College. She co-discovered Pfiesteria, a toxic estuarine organism stimulated by nutrient over-enrichment, in the 1990s. The N.C. Watershed Coalition presented her an award at Catawba College for her research on this organism, which can cause major fish kills. Burkholder spoke recently to Juanita Teschner about the harmful effects of nutrient over-enrichment and pollutants on the state’s rivers and reservoirs. This is an edited transcript of that interview.
Q: What has your research on aquatic ecosystems revealed about North Carolina rivers and public water supplies?
A: Research by my laboratory and colleagues working with us has shown that many N.C. reservoirs and estuaries are degraded from nutrient over-enrichment and associated pollutants. The affected reservoirs include some of the state’s most important drinking water supplies.
Q: Where do the nutrients come from and what happens when they overload the rivers?
A: The public is generally aware that nutrients can be a great thing. Nutrients are what homeowners put on their lawns to stimulate their garden plants. But if you have too much of a good thing, it can become a force that can really push an aquatic ecosystem out of balance. The two main nutrients that we worry about in water science are nitrogen and phosphorus, which are found in our sewage and septic tank effluent leachates. They are found in fertilizers for lawns and croplands, and in car exhaust. And they are found in animal waste and animal waste leachates and effluents that get into waterways. So both runoff and atmospheric sources that are human-made are entering our waterways, and when they do, they stimulate the plants that are in the water.
Q: Why are the plants in the water so sensitive to the nutrients?
A: The plants that are in the water are called algae. They are primitive plants and they are typically very tiny – sometimes a million in a teaspoon of water, sometimes even more. So you can imagine what happens when these little plants with this enormous surface area relative to their tiny size are immersed in a nutrient bath that we create through all the pollution that we are adding. This is far different than putting some nutrient salts on a flowering plant in your garden and then watering it to make sure the nutrients get down to the roots. These are very small plants immersed in a bath of nutrients. No wonder aquatic ecosystems are incredibly sensitive to nutrient over-enrichment compared to land plants.
Q: What role does sediment play in river degradation?
A: Some nutrients stick to sediment particles, and then they come into a waterway and move away from the sediment particles because the water chemistry is a little different. Then they become more accessible to algae again. Some nutrients are highly soluble. They don’t stick to anything, like nitrates. So they just come into waterways from cropland runoff or car exhaust or whatever. So there are lots of complexities about nutrient availability but the fact is our state’s surface waters in general are very nutrient-overloaded. They are also often overloaded with other pollutants like all the sediment from land disturbance. So sediment and nutrients are often associated and unfortunately, depending on the nutrient source – if it’s animal waste effluent leachate or poorly treated human sewage – then fecal bacteria are associated as well.
Q: When the algae grow too much, what happens to the water system?
A: When algae start to overgrow a system, at first it may not be too much of a problem. In fact, it may be that there’s more food for other organisms to eat, but it doesn’t take long before they begin to be like too many nutrients on your lawn causing weeds. During the day they take sunlight and make oxygen in photosynthesis, but at night they have to breathe, too, and the lights have been turned off. They are not making oxygen any more. They have to use oxygen.
Again you have to think of all these millions and millions and millions of little tiny plant cells in water with their enormous surface area relative to their size. They just suck up all the oxygen from the water so that fish suffocate to death. That’s one of the first things that happen. When those blooms die, bacteria degrade them and try to re-release the nutrients back by decomposing all that dead material. And because there is so much more of it than there should be in a system that is out of balance, the bacteria use all the oxygen in trying to decompose the biomass. So that exacerbates the dissolved oxygen stress problems for beneficial aquatic life.
Even though many of the algae that I’ve talked about are really good for aquatic ecosystems, because we have added too many nutrients, there are too many of them and they become a nuisance. But among the algae are also certain rogue species that make chemical poisons. And among those are a group of algae that used to be called blue-green algae, now called cyanobacteria, and those organisms absolutely love nutrient-degraded waters. They are phosphorus-loving in particular. And so worldwide, certainly in our state, cyanobacteria are thriving in nutrient-degraded waters. They make chemical poisons that can cause serious human illness and even death. And they can also kill aquatic life with their toxins.
Q: What kind of serious human illness?
A: Liver disease, liver hemorrhaging, liver failure, neurological problems, lots of gastro-intestinal problems. They make a large array of toxins. And because our waters are so turbid, cyanobacteria are thriving here, but they don’t seem to be making too many toxins compared to some of the other systems I’ve studied that are little bit clearer. But as soon as the water clears here between storm events, then they can take off and make toxins.
Q: How do you get rid of cyanobacteria?
A: You can remove cyanobacteria toxins from the water if you’re a water treatment plant operator. It’s just that to do that requires expensive filters – carbon filters in particular. So water treatment plants can keep drinking water safe for people. It’s just that it’s much more expensive because those carbon filters cost a lot of money. So a lot of water treatment plant operators don’t use carbon filters unless they become aware that there’s a problem. So you can see that’s a potential recipe for not good news.
Q: Do we have any areas in North Carolina where we have a particular problem?
A: It’s interesting that you ask that question. You’ve heard the old adage, “If a tree falls in the forest and nobody hears it, nothing happened”? The waterways in our state are pathetically monitored. They are mostly not monitored at all. If concerned citizens call in and say, “This water has turned bright green. Something is really wrong out here. What’s going on?” it might be that our environmental agency can go and check. But this state, even back in the late 1990s, had a lot to catch up on and that’s why the Clean Water Management Trust Fund (CWMTF) was and is so important. But, as you know, its funding was cut 90 percent. Our state for years has ranked anywhere from 43rd to 47th in the country in environmental protection spending per capita. We just made it down to the bottom. We are either 49th or 50th.
Before this legislature slashed this very poorly funded environmental agency, it was only able to monitor a given river, like the Neuse, monthly for a year and then it didn’t monitor for four years – 12 times in five years. For the past three years, there have been some very toxic cyanobacteria blooms on the Cape Fear. That’s just one place among many that I’m sure they are going on, but who knows right now?
Q: What environmental changes have you tracked in your research?
A: What I’m seeing is based on going around the state and assessing reservoir water quality for a summer snapshot and then also in a much more concerted effort I have long-term databases with high frequency sampling on three drinking water reservoirs in the state and also on the Neuse estuary where we have been tracking water quality changes for 18 years with high frequency data, bi-weekly to monthly.
Q: What have you found with the Neuse?
A: Unfortunately, water quality in the Neuse is deteriorating. We have tracked it over time and it is continuing to degrade, especially increasing algal blooms and increasing ammonia concentrations in the Neuse estuary.
Q: Is the ammonia from swine operations?
In the upper watershed we have also been tracking land use changes and relating those to water quality. In the upper watershed, like in the Falls Lake area, the problem is mostly urban. But down in the mid-to-lower watershed the major contributors are the swine industry.
Q: What are the urban sources?
Urban influence is non-point, so diffuse sources coming off our roads, runoff when it rains that carries oil from our cars and heavy metals in the car exhaust that deposit on roadways, also fecal bacteria from pets. There’s a set of studies done, for example, in the Wilmington area by Dr. Mike Mallin of UNC –Wilmington which shows that pet wastes really are a major problem. They are all part of the urban story.
I should also mention sewage treatment plants. In the upper part of the Neuse watershed, there are a lot of what are called little package plants. Those are plants that are put into individual developments, and they are very poorly run and, once again, our completely strapped state agency cannot monitor or track them. So they are a big part of the problem in the upper watershed. In the lower Neuse watershed it’s agriculture, specifically swine operations.
Q: What needs to be done?
A: There are a lot of things that would be really helpful. The first is to develop some strong, serious controls of nutrients. Right now, our state has some excellent sediment erosion control laws, but there’s almost no enforcement because the state agency is so funding-strapped. They can’t get out there to do the inspecting so it doesn’t do much good to have strong laws on the books if nobody is there to enforce them.
I think it would be really good to have numeric nutrient criteria. There are some very important waters in the state that are commonly out of compliance with the state standards for chlorophyll. Some of them end up on our state’s list of degraded waters and from there they are supposed to be cleaned up but this goes on year after year after year. Even the Falls Lake rules that were recently passed aren’t supposed to finally allow part of our Falls Lake to meet the state standards for chlorophyll until 20 years from now.
Q: What’s going to happen if these waters are not cleaned up?
A: I think you’ll just see further degradation, and it will be harder and harder and cost more and more for our water treatment plant folks to make the water safe for us to drink. The city of Raleigh is a good example. They have tracked total organic carbon – all the algal biomass that’s created by too many nutrients – over the past decade or so and it’s really increasing in the lake. The U.S. EPA has criteria in which if total organic carbon goes above a certain level, the water treatment plant has to do a lot more to make sure the water is safe. That’s because total organic carbon and chlorine, which the water treatment plant has to add to clean the water, react together and make carcinogenic compounds.
So the water treatment plant is forced to do a lot more to clean that up, and in trying to disinfect the water and make it safe for people to drink, they inadvertently make carcinogenic compounds. So it’s a pretty vicious cycle. The city of Raleigh determined that it will cost the city something like $450 million if total organic carbon in that lake doesn’t begin to go down in just a couple of years.
One of the major problems with water pollution is that people can’t see a lot of the worst of the problem. It’s really out of sight, out of mind. The water might look fairly pretty but it’s extremely polluted.
Q: What will happen in five years if something isn’t done?
The cost will continue to increase. The CWMTF was doing such great things across the whole state and now its funding has been gutted. I don’t understand how a legislature can say it has the public health’s best interest at heart because our environmental agency cannot answer questions like yours about where the problems are. They are not able to monitor. Fundamental things like that need to change.
The Center for the Environment at Catawba College was founded in 1996 to provide education and outreach centered on prevalent environmental challenges and to foster community-oriented sustainable solutions that can serve as a model for programs throughout the country. For more information, visit www.centerfortheenvironment.org or www.campaignforcleanair.org.