LSU SVM fish toxicologist studies the effects of surfactants on fish populations
Kevin Kleinow, DVM, PhD, is a toxicologist who specializes in environmental health issues, especially those related to fish. This means he studies how contaminants in the environment affect fish and how those interactions may affect other organisms, including humans. With the oil spill in the Gulf, Dr. Kleinow has redirected ongoing work on domestic and industrial surfactant input into aquatic environments to dispersant use with the oil spill. Surfactants, major components of dispersants, are being examined as to how they may affect the uptake and fate of petrochemicals in the fish.
“I was interested in a number of areas in the biological sciences as an undergraduate,” said Dr Kleinow. “During a course on Invertebrate Zoology, the professor, a limnologist (a lake specialist), told me about a summer fellowship from the National Science Foundation. I competed for it, and I got it. It was a great summer experience that was a career-directing event, introducing me to fish, the environment, and toxicology.” The fellowship allowed Dr. Kleinow to work at the Great Lakes Water Institute a University of Wisconsin facility. Now, part of the School of Freshwater Sciences and administered by the University of Wisconsin-Milwaukee, this facility is the largest freshwater research institute in the country.
Dr. Kleinow later received his DVM from the University of Minnesota with subsequent training in Aquatic Animal Medicine through Cornell University and the University of Pennsylvania’s Aqua-Vet program. He completed his PhD at the University of Wisconsin-Milwaukee in a hybrid program incorporating environmental and fish elements and classical toxicology/ pharmacology from the Medical College of Wisconsin. After graduation and a three-year National Institute of Environmental Health Sciences (NIEHS) post-doctoral training fellowship at the NIEHS Freshwater and Marine Biosciences Center at the Medical College of Wisconsin, he joined the faculty at the LSU SVM in 1987 in the area of veterinary physiology, pharmacology, and toxicology.
Much of Dr. Kleinow’s work with fish has centered on how fish deal with environmental contaminants or drugs. Biotransformation of chemicals to more excretable forms and transport within and out of the fish are major-components of these studies. The outcome of these processing events is influential in the food chain transfer of chemicals through the aquatic and marine food chains and to humans. During studies examining the bioavailability and fate of chemicals known to be endocrine-disrupting chemicals, Dr. Kleinow noted increased bioavailability and retention of co-exposed dietary chemicals. He noted that the chemicals that elicited this behavior were also surfactants. Drawing on past training and recent literature reviews, he correlated that surfactants, when added in significant amounts, increased intestinal bioavailability of oral medicines and inhibited transporters involved in drug excretion. From these observations and uses, Dr. Kleinow postulated that surfactants discharged in the environment—even at low concentrations—would alter the uptake, excretion, retention, and potential toxicity of other chemicals in the environmental food chain.
Subsequent work in his laboratory on the dispositional aspects of this hypothesis showed that indeed this was true. Surfactants appear to do this by changing the permeability of membranes in the intestinal wall and places of excretion, such as the biliary tract. Dr. Kleinow added, “It’s sort of like a levee along the river. If the levee is leaking and our pump is big enough, we pump the water back over the other side and there’s no problem. But if the leak becomes too big, the pumps won’t be able to keep up, and we get water over here. And that’s what happens with the surfactant; it progressively increases the permeability so more and more compound gets into the animal from the higher contaminant concentration in the diet in the intestine, increasing bioavailability. In a similar fashion, but with opposite results, surfactants prevent the transporter-mediated concentration of contaminants into the bile necessary for excretion. Leakage back from the bile lowers the amount of contaminant available for excretion. For both venues the net result is increased compound equivalents in the fish. Surfactants themselves, having low relative toxicity as a group and hence widespread use in shampoos, detergents and the like, could facilitate the toxicity of other chemicals potentially much more hazardous to the fish.
As it relates to waters directly affected by the Gulf oil spill, a foreign substance—oil—has been introduced into the water. Dispersants break up the oil, making it easier for natural bacteria to break it down. This is a good thing; however, initially there may be too much oil for the bacteria to act upon. “Well, it’s just like you or me going to a buffet. Once you get full, it doesn’t matter how much more is on the buffet, you’re not going to eat anymore,” said Dr. Kleinow. By adding dispersants to the water to break up the oil, surfactants in the dispersants not only increase access of the non-remediated oil to the fish, but also could cause select toxic compounds in the oil to be absorbed more rapidly and make it harder for the fish to excrete those compounds.
Dr. Kleinow believes the most important benchmark of the spill’s effect has yet to be played out. There is plenty of evidence suggesting that the most sensitive stages to the effects of oil are the embryonic stages of fish and other organisms. These early life stages—many of which reside in the marshes—are the upcoming generations and the future of the Gulf. Dr. Kleinow hopes his studies with surfactants as applied to oil with embryonic fish and studies with soot from combustion of oil spill constituents (with colleague Dr. Arthur Penn, professor of toxicology) will help delineate plausible remediation approaches to the contaminated wetlands containing these sensitive organisms.