Steve Twidwell: I'd like to say hello to everybody out there who would like to ask questions. I look forward to trying to answer them.

Steve Twidwell: It's very important to have both clean AND balanced waterways, because a nice balanced system is one that can handle natural pollutants and deal with them in a good way. The problems develop in waterways where an unbalanced situation develops. Sometimes it might be overstimulation by nutrients (which causes algal growth), while other times it might be an influx of oxygen demanding materials which can deplete oxygen in the water and stress aquatic organisms there.

Steve Twidwell: Most states, like Texas, have a routine monitoring network of stations where water is monitored on a regular basis. Assessing that data over time gives us a picture or trend of what's happening with the water quality. It can be improving, it can be degrading, or it can be staying basically the same or showing a nice steady trend. If the water quality is shown to be declining, then often special studies are conducted and more intensive sampling is done to determine the cause and source of the problem. And then, based on that assessment, hopefully the problems can be remediated.

Steve Twidwell: As a young boy I was always interested in being in nature - I liked to swim, I liked to fish, I liked to turn over rocks and see what was under them. So, when I had a chance to study, it was always science that I preferred, not only in high school but in college as well. The science of living things is really called biology. In college I developed a real interest in the biology of water and tried to take as many courses as I could to advance my knowledge of aquatic biology.

Steve Twidwell: Sometimes toxic materials in water can affect other organisms that are not in the water. For example, low levels of mercury in the water can bioaccumulate (increase in concentrations) as they move up the food chain. That's why sometimes larger fish that are long lived accumulate high concentrations of mercury. Fish-eating birds or raccoons, for example, that feed on those fish can be harmed by the high concentrations of mercury that are found in the fish. The ultimate predator, which is man - that's you and I - can also be harmed by these high concentrations if he consumes mercury-contaminated fish.

Steve Twidwell: I would say some common sense things. The water should be generally clear, so it doesn't seem cloudy or turbid or have an unusual color to it. There should not be an inordinate number of aquatic plants. Those are really the two general things that we look for as an outward sign of good water quality.

Steve Twidwell: In some respects, specifying the correct balance is a little bit difficult because there are so many things, but in terms of priorities, what we look for is dissolved oxygen; for example, it should not be too high or too low, but in a range that is tolerant to a wide range of aquatic organisms. The same could be said for the pH (relative acidity) of the water, which should be in the middle of the range - not too acidic or too alkaline. Most states, like Texas, have written water quality standards which strive to maintain a balance in the water. So, if you are interested in balance, you might want to contact your state agency for a copy of the standards that are applicable to water bodies within your state.

Steve Twidwell: It's a difficult question to answer because it depends on what kind of pollutants were released. In some cases it is a matter of weeks - for example, if it was an organic spill from a wastewater treatment plant. It might take a year to more if it's a discharge of toxic-related material. Here in Texas we had one spill that occurred in the 1970s that happened to be a spill of wastes contaminated with mercury. That spill - more than thirty years ago - is still affecting water quality in Lavaca Bay.

Steve Twidwell: I'll just mention a couple that are on our hit list. One is dioxin, which is a very toxic, persistent, organic chemical. And then I would also mention mercury, which is a metal that has caused some widespread problems here in Texas. But really, there are many toxic substances that can affect aquatic life and we consider them all very important.

Steve Twidwell: We would have to say that in Texas, at least from our perspective, it is the rivers and streams. We have very good quality of water in the Gulf of Mexico, at least along the Texas shoreline. There is only one existing problem there - a consumption advisory for mercury in king mackerel. Of all streams and rivers in Texas, we have more than 150 water bodies with varying degrees of problems.

Steve Twidwell: In general, all living things need some phosphorous. However, in high concentrations it can stimulate an overgrowth of aquatic plants - I am speaking here primarily of algae. Those algae, then, by their metabolism can cause depletion of dissolved oxygen, which then causes serious problems for the aquatic life living there. There are many water bodies in Texas that have high levels of phosphorous, yet do not cause excessive growth of aquatic vegetation. It is difficult sometimes to generalize that just having elevated levels of phosphorous will cause a problem. It is dependent upon many other variables.

Steve Twidwell: Well, I think the dialogue that has ensued since the enactment of NAFTA has been good. It has created a relationship between our two countries where all topics are open for discussion. In Texas we still have serious problems in the Rio Grande, primarily downstream of the major U.S./Mexico border cities. Most of these problems are caused by poorly treated domestic sewage from the Mexican side.

Steve Twidwell: Through studies of our own we have enacted biological criteria which allow us to sample the fish and bottom dwelling organisms, identify and count them, and use an index to tell us how good the water quality is. This process has moved us away from traditional approaches of just looking at water quality parameters.

Steve Twidwell: I think without a doubt the highly concentrated populated areas have the most serious problems, mainly because they have to deal with treating waste materials from such a large population and, in that sense, achieving adequate treatment is sometimes difficult.

Steve Twidwell: In Texas we have virtually eliminated most of the dissolved oxygen problems with the state waterways that have been due to municipal and industrial discharges. The biggest problem we are facing right now is dealing with the impact of non-point source runoff. We have more problems related to poor bacteriological conditions in waterways than anything else.

Steve Twidwell: We've had water quality standards in place since 1968.

Steve Twidwell: I think the issue of controlling population is one that would be difficult to manage, and it's a sociological issue more than anything else. Most of the problems related to availability of water in Texas have been related more to drought in recent years than to actual population problems.

Steve Twidwell: I think that would be a difficult question to answer. All state standards must be approved by the Environmental Protection Agency, which strives for consistency among states while allowing them each some flexibility.

Steve Twidwell: I think most monitoring agencies have well-defined procedures and protocols for taking samples and making measurements. The biggest problems we see is the problem of monitoring agencies for adhering strictly to those procedures. It's very good to maintain documentation of how samples are collected and measurements are made so there can be no doubt about the quality of those samples and measurements.

Steve Twidwell: In the beginning the water quality standards were set on all of the major water bodies at the time. We are required to revise our state water quality standards every three years. At that time we open the doors for suggestions from the general public, other agencies, and universities and colleges to give us suggestions on other water bodies that are deserving of state water quality standards.

Steve Twidwell: I would say that it varies by water body type; a little each year, and it is difficult to generalize across all those groups. There are other variables that come into play here also. For example, here in Texas we have a very large number of streams that do not flow year round. In Texas there are also many small reservoirs which were constructed for purposes other than recreation or public supplies. But in general terms, we sample or assess about sixty percent of all water body types and as much as ninety percent of the larger reservoirs in the state. In terms of impairment, of those that we sampled roughly one-third show some form of impairment.

Steve Twidwell: We have ongoing problems with bacteriological problems across the state. It's proving very difficult to arrive at a solution to fix these problems, since they are so diffuse in nature. We are looking at developing approaches to control non-point source runoff so as to capture the bacteria before they enter waterways. However, this is still an ongoing problem.

Steve Twidwell: It's a very common procedure for sampling fish communities. We use the technique ourselves when we are sampling fish for an assessment. We also use electrofishing to sample for fish for tissue analysis. The electrofishing equipment allows you to set the amount of electricity that passes through the fish so that they are only stunned momentarily. That allows us to capture them with a net and return them live to the water body when we are finished. It's only rarely that a fish is actually killed in the process.

Steve Twidwell: I think that question gets to the political side of water quality issues. In Texas we are striving to maintain a robust economy and yet, at the same time, we require very stringent water quality treatment for both industrial and domestic wastewater treatment plants. We have always felt a need in Texas to balance the environment and the economy.

Steve Twidwell: In most cases, drought is variable. There are some areas of the state, obviously, that get less rain than others. The gradient is from west to east primarily, with west having less rain and the eastern part of the state having more rain. The same can be said from north to south, with northern areas of the state (except the panhandle) receiving more rain than areas in the south.Droughts occur in pockets of the state where the normal rain simply doesn't fall for extended periods. Sometimes these pockets overlay population centers and sometimes they don't.

Steve Twidwell: That depends largely on the degree of the point source discharge. If the point source discharge is large in relation to the receiving water, it can be a very serious problem. Factored into this equation also has to be the concentration of the waste stream. Point source problems have one advantage to them in that they can be corrected by tightening the treatment process. Non-point source problems generally are not as severe, but are much more difficult to control because of their diffuse nature.

Steve Twidwell: The group I work in is responsible for coordinating monitoring at our fifteen regional offices statewide. We also work closely with about twenty river authorities and also with volunteer groups. We look for consistency in sampling procedures among all these groups.

Steve Twidwell: I appreciate that comment. In my time working here with the TNRCC, I've been fortunate to see dramatic improvement in water qualitystatewide. These improvements came about because at the very base of the decision-making process was water quality data that we collected.

Steve Twidwell: I have always felt that the most important part of my job is to collect scientifically valid data. If the data are good, in most cases the decisions made on them cannot be disputed.

Steve Twidwell: The TNRCC is a very big agency that has responsibilities for regulating air and water quality across the state. We accomplish this primarily by monitoring both the air and water, assessing the data, and writing permits that control the amount of waste materials that can be discharged into the air or water, then the cycle starts all over again. That is a simplified picture of what we do.

Steve Twidwell: This is a strange story. It's a story that seems like it just began a few years ago, but in essence we've probably had a mercury problem for many, many years. The mercury problem was only discovered by chance in another state. In this state, the fish were sampled in a different way. Most state agencies collect fish and send them to a laboratory for whole body analysis. Arkansas, on one study, decided to send in only the muscle tissue. What they found was an accumulation of mercury in the predatory game fish, and only those that were long-lived and large sized. Many studies have been done since this time to show that mercury moves up a food chain only in certain cases - the dissolved oxygen in the bottom waters has to be near zero, the pH of the waters has to be acidic, and there has to be presence of organic material in the waters. If those conditions are prevalent, then mercury can be transformed from an inorganic to an organic form by bacteria. That organic form then moves up the food chain. The conditions I've described generally occur only in east Texas. That's why the fish in central Texas, for example, have generally low concentrations of mercury in their tissue. The amount of mercury that falls from the atmosphere across the state is basically the same.

Steve Twidwell: That depends a little on the parameter that you are interested in. If it's clarity - simply being able to see through the water and that you might want to try snorkeling or diving in - the top five would be Lake Travis, Canyon Lake, Armistad Reservoir on the Rio Grande, Choke Canyon, and Stillhouse Hollow. The bottom five would be Rita Blanca Lake, Cox Lake, Lake Kickapoo, Old Marlin City Lake, and Lake Texana.

Steve Twidwell: I have always felt that water quality monitoring and data assessment is important regardless of who's doing it. We value having monitors out on water bodies that we either do not monitor or monitor very infrequently.The observations that you make as a class in your monitoring efforts are invaluable.

Steve Twidwell: It's a little difficult to answer a broad question like this,but I can just tell you that as the water quality deteriorates, the number of organisms that can tolerate or ultimately survive is diminished. When I started monitoring, there was a stretch of the San Antonio River below San Antonio where no fish existed at all, and only the most tolerant worms that were found in the bottom were able to survive.

Steve Twidwell: I believe strongly that environmental education should be taught at very early ages in the school system. This exposure not only provides information, but it provides a basis for those students to make sound decisions in the future.

Steve Twidwell: The groundwater monitoring folks try to do the same thing that we do on the surface. They sample ground water by sending instruments down existing wells to measure the water quality or use a device to pump the water to the surface where it can be sampled and measurements made. In some cases, we actually drill holes ourselves for sampling purposes.

Steve Twidwell: I think that in Texas we have exceptionally good water supplies.There are only a few cases where our drinking water supplies are threatened. In most cases, pollutants can be removed at the treatment plant. There are some pollutants - particularly in the upper part of the Brazos, Colorado, Red, and Canadian Rivers - that are not easily removed. I'm talking here of elevated salt concentrations and, from a public water supply standpoint, these would be considered our most serious threats.

Steve Twidwell: We are doing the best job that we can to monitor the air pollution coming from all sources, and at the same time we're trying to write permits that control those waste discharges to the air.

Steve Twidwell: Quite to the contrary, the government - both at the state and federal levels - continues to tighten water quality standards and make water quality discharge permits more stringent.

Steve Twidwell: There is a wide range of jobs available for aquatic biologists.Here in the state of Texas, each of the major agencies responsible for monitoring and protecting water quality have many jobs available. I'm speaking here primarily of the TNRCC, the Texas Department of Health, the Texas Parks and Wildlife Department, and the Texas Water Development Board. There are jobs available for monitoring our water bodies, sampling fish, sampling the flows into the streams, and a wide range of other possibilities.

Steve Twidwell: I'll give you just a couple of examples that might have some relevance to you. If you, for example, apply too much fertilizer to your yard, many times the grass and vegetation cannot take up the excess. When it rains or when you irrigate the yard, that excess will be carried with the water to the nearest water course where those nutrients, instead of stimulating the growth of your grass, will stimulate the growth of algae in the streams.

Steve Twidwell: Most of the publications for which I have written have resulted from monitoring work that others have done. For example, I told you today about our routine monitoring program. If our routine monitoring data shows declining water quality, we as a group here in Austin conduct what we call a special study. That special study will determine, hopefully, the cause and sources of the problem first revealed by our routine data. The special study reports are reports that we have summarized the findings of our more intensified monitoring effort. I have been lucky, though, to pursue other research efforts here at the agency. I've developed techniques for monitoring attached algae and for determining the oxygen demand of sediments. I've conducted mercury studies and limiting nutrients studies. These are just a few examples of other things that I have done.

Steve Twidwell: I just want to thank everyone for sending in your questions. I thought all of the questions were relevant and thought-provoking, and I hope that I have stimulated some of you to consider a career in aquatic biology. Thanks for participating!