Dalton Gossett has bachelor and associate degrees in biology and a Ph.D. in plant physiology, and has lived in the Shreveport, Louisiana area for over 25 years. He has taught undergraduate courses in biochemistry, animal physiology, and environmental science. He has also assisted undergraduate and graduate student research in biology, and his research interests include environmental parameters related to maintaining and improving water quality.
Tim Shaughnessy interviewed Dr. Gossett following a Feb. 22nd lecture entitled “Long-term Environmental Impact of Birth Control: The Release of Estrogens into the Environment.”
T&C: Dr. Gossett, with your academic background in biochemistry, water quality, and environmental science, what specifically motivated you to research the presence of estrogen-type compounds in the Shreveport-area water system?
DG: This project began with a discussion with a colleague at the LSU Agricultural Center Red River Research Station in Bossier Parish. We were discussing the use of chicken litter as a fertilizer, and we begin to talk about the possible impact of estrogen release from this litter. We were initially going to do this as a joint project, but he retired before we finally had the equipment necessary to do the analyses.
T&C: Your research seem consistent with other studies from around the US and elsewhere that have found similar results of a high presence of synthetic hormones mimicking estrogen in rivers and streams around cities, causing malformation in fish populations. Before you began your research, did you expect to find similar results in Shreveport?
DG: I expected to find EEDCs (estrogenic-endocrine disrupting compounds) in the runoff from the chicken litter, but I had no idea if the constructed wetland would significantly reduce the levels before the water left the research station. I had no idea what we would find in the rivers and lakes. I was not even sure about the Red River, because I was not sure if the population was sufficient to contribute significant levels of EEDCs.
T&C: In layman’s terms, what compounds were you attempting to detect? Some of these compounds occur or are produced naturally by humans and other animals; does their presence in the water system pose the same concerns that artificially-produced compounds do?
DG: Three of the natural compounds (estrone, 17 β estradiol, and estriol) are commonly referred to as estrogens. The fourth natural compound is progesterone. The synthetic compound is ethinyl estradiol. The presence of the natural compounds causes the same concern as the synthetic compounds.
T&C: What are some of the problems associated with exposure to high doses of these compounds? There has been a lot of work on the problems it causes for fish; are there studies that directly examine the effects of these compounds on humans (who unknowingly ingest them through water sources)?
DG: Health effects attributed to endocrine disrupting compounds include a range of reproductive problems including: reduced fertility, male and female reproductive tract abnormalities, and skewed male/female sex ratios, loss of fetus, menstrual problems; changes in hormone levels; early puberty; brain and behavior problems; impaired immune functions; and various cancers.
T&C: You mentioned in your lecture that of the three types of naturally-occurring estrogen, almost all chemical contraception is based on the most potent or concentrated type. Is it possible, in analyzing water samples, to distinguish the presence of the natural vs. synthetic estrogen? I.e., if you detect the presence of this potent variety, can you attribute a rough percentage of how much of it is due to what humans (or animals) naturally produce vs. how much is due to taking contraceptives?
DG: It is difficult to tell for sure. Of course we know that any ethinyl estradiol (EE2) comes from the use of contraceptives. However, some contraceptives also use a combination of natural EEDCs and EE2, and it is impossible to tell whether these EEDCs are naturally produced or derived from contraceptive use.
T&C: I believe that most of the common forms of oral contraceptives are of a low dosage such that their effectiveness decreases quickly if they are not taken very consistently. Yet recently many varieties of “emergency” contraceptives (e.g., the morning-after pill, Plan B, etc.) have been developed that are of much higher dose. Would the effect on fish or human populations differ between these two types of contraception? Would the more concentrated type remain in the water supply for a longer time, potentially causing a larger impact on the environment?
DG: The impact of the EEDCs on fish or human populations would be the same with either type of contraceptive because the “morning after pill” is just a higher dosage of the same compounds used in the daily contraceptives. It is possible that the high dosage EEDCs would take longer to break down in the environment just because there is more to break down; however, I have not seen any data to confirm or deny this.
T&C: One of the controls in your research to determine the effect that humans have on the presence of estrogen in the water was to examine water samples both upstream and downstream from municipal water treatment plants. How big was the difference in the presence of these compounds upstream and downstream from the treatment plants? I.e., how big of an impact are humans having on the presence of these compounds in the water system?
DG: The increases ranged from as low as from 1 ng/L to 10 ng/L of estriol on 9/23/2011 to as high as from 1 ng/L to 47 ng/L of ethinyl estradiol on on 9/23/2011.Since these levels were measured above and below the Lucas treatment plant, we can say that humans were responsible for all of this increase and are, therefore, having a large impact on the presence of these compounds in the water system.
T&C: Is there a limit to the geographical range of harm for these compounds? In other words, assuming that water coming out of a treatment plant is contaminated with these compounds, do they stay in the water supply for a significant amount of time? How far downstream would a neighboring city or fish population have to be to be unaffected by compounds coming out of Shreveport?
DG: The compounds will be broken down in the environment, but the amount of time it will take and how far these compounds move downstream depend on numerous factors including water temperature, pH, contamination load, oxygen levels, flow rate and other factors. I have not conducted nor have I seen the results of such studies on the Red River.
T&C: Most people would probably presume that their local water treatment plant is successfully filtering dangerous or artificial chemicals out of the water that goes back into rivers and streams. Is this assumption valid? How successful are water treatment plants at removing the types of compounds you studied?
DG: Contrary to popular belief, water treatment plants very rarely filter the water at all and never subject water to the type of microfiltration it would require to remove these chemicals from the drinking water if they are present.
T&C: You found a high presence of these compounds downstream of the water treatment plant, but no significant amounts in the main water source for the city of Shreveport (Cross Lake). Should Shreveport citizens therefore be less concerned that the use of contraception directly affects the water used for drinking, cooking, and bathing?
DG: Yes, based on our studies, the people who get their drinking water from Cross Lake have reason to be less concerned about the presence of EEDCs in their potable water than people who get their potable water from sources such as the Red River.
T&C: Given the results of your and similar studies about the detrimental effects of synthetic estrogen on human and fish populations, have there been efforts on those involved in environmental science to come up with remedies? What form do these remedies take; i.e, does the field see more effort being put into improving methods of removing these compounds from water supplies, or into reducing the use of these compounds in the first place? Is one of these solutions preferable, in terms of environmental quality, to the other?
DG: The magnitude of the EEDCs problem is just now being realized. Although I do not know of any specific study, there are probably scientists working on solutions to remove the EEDCs from the water ways, which would be the most preferable solution to the problem. Any long term improvement in environmental quality is going to depend on a decline in population growth. Since oral contraception appears to be the most successful way to reduce population growth, the overall environmental health of this planet is most likely going to depend on the continued use of EEDCs.
T&C: It seems, then, that scientists would be working at cross purposes; if there is a demonstrated harmful effect of EEDCs in the water (not only to humans but to other plant and animal populations), then would not environmental quality be harmed if the use of EEDCs increased (for the purpose of keeping human population low)?
DG: Like almost everything in the environmental realm, there are trade-offs that have to be made. For example, there is no doubt that the burning of fossil fuels is resulting in a greenhouse effect that may eventually lead to global warming and significant rises in the sea level. However, to immediately cease the burning of fossil fuels would be catastrophic. Hence, we trade off the continued burning of fossil fuel with the threat of global warming for continued economic growth and our current standard of living. Almost all environmental scientists will tell you that the earth has just about reached its carrying capacity, and that there is no way the environment can stand another doubling of the population in the next 40 – 50 years. By this, I mean that even today, there are not enough resources to maintain the current world population of close to 7 billion at the current standard of living enjoyed by the people in the U.S. and other developed countries. If the population doubles to 14 – 15 billion people, which it is projected to do within 40 years at the present growth rate, there will not be sufficient resources to maintain the world’s population even at a poverty level. Hence, another trade-off. The risk of adverse health effects due to the small amount of EEDC’s that might be present in the drinking water in some areas is less than the risk of the environmental disaster that is likely to develop in the face of unchecked population growth.
T&C: What can people do at home to try to limit their intake of these hormones? Will common home filtration systems (e.g., Brita, Pur) remove these compounds from drinking water?
DG: We routinely filtered our water samples through 45 micron filters before we ran the analyses; therefore, unless the filter system uses something much smaller, which is unlikely in any home filtration system, there is no simple way to remove the EEDCs, if they are present.
Even though Catholics would disagree strongly with the notion of the value of reducing population via contraception, and would generally disagree with the benefit of population reduction, the major findings of Dr. Gossett’s research on the harmful effect of contraceptive hormones on the environment still stand.