Detecting the “Fingerprints” of Endocrine Disruption
Ship to Shore: Pioneering use of technology sheds new light on endocrine-disrupting chemicals in Southern California’s urban ocean
Although thousands of anthropogenic compounds are detectable in urban aquatic environments today, less than 200 are routinely monitored and regulated by governmental agencies. Worldwide, wildlife and humans are exposed to increasing quantities and types of persistent industrial, domestic, and pharmaceutical chemicals, many of which are classified as endocrine-disrupting compounds (EDCs) since they significantly alter endocrine systems and consequently disrupt important physiological functions and health. The list of currently monitored chemicals includes compounds formerly found in coolant fluids (e.g. polychlorinated biphenyls or PCBs) and pesticides (e.g. dichlorodiphenyltrichloroethane or DDT) and current fossil fuel byproducts (e.g. polycyclic aromatic hydrocarbons or PAHs). Missing from the list are the increasing numbers of contaminants of emerging concern (CECs), which include pharmaceuticals (including steroids), personal use compounds (e.g., triclosan), current-use pesticides (e.g., bifenthrin, permethrin), and various industrial and manufacturing-related compounds (e.g., flame retardants, nonylphenol, phthalates). The effects of most CECs in marine organisms or humans are not understood. Some will undoubtedly become identified as EDCs once they are investigated, while some others may have effects unrelated to the endocrine system but which also threaten health.
Dr. Kelley’s research team is particularly concerned about marine organisms that live in urban coastal waters that are contaminated with legacy or industrial compounds (like PCBs, DDTs or flame retardants) as well as wastewater treatment plant (WWTP) outfalls farther off the coastline that contribute many CECs into the environment. Coastal WWTPs in Southern California discharge over 942 million gallons of treated wastewater into the ocean every day. Although this water meets some of the highest cleaning treatment standards that exist in the country for discharged wastewater, it still carries the difficult-to-remove contaminants (e.g., estrogen in birth control preparations, nonylphenol, valium, and many others). Moreover, stormwater runoff, most of which does not get captured and treated, carries with it to the ocean additional contaminants. Clearly, these highly populated “urban ocean” settings make a perfect laboratory for the study of environmental toxicology and endocrine disruption in California’s marine wildlife.
A Basic Primer on Endocrine Disruption
The endocrine system is made up of glands throughout the body (e.g., the hypothalamus, pituitary, thyroid, pancreas, adrenals, testes, ovaries) and the hormones that are produced by the glands. These hormones (e.g., estrogen, testosterone, growth hormone, insulin, epinephrine, cortisol, and many more) travel through the bloodstream, acting as chemical messengers, regulating many critical bodily functions such as metabolism, blood sugar levels, reproductive function, development, immune function, stress responses, and growth. Mammals (including humans), fish, birds, and all other living organisms have endocrine systems. An endocrine disrupting chemical (EDC) is one that affects the normal functioning of the endocrine system by mimicking the behavior of hormones, by blocking the effects of hormones, or by altering the levels of hormone or their receptors in tissues. At a cellular level, the presence or absence of hormones (or mimickers) regulates the expression of many genes within a cell, which, in turn, up- or down-regulate the production of particular proteins within a cell. For example, the hormone cortisol is produced by specialized ‘interrenal’ kidney cells in fish (or by the adrenal gland in humans) when the fish encounters stressful environmental circumstances. Cortisol then turns on the appropriate genes in various cells and tissues that make proteins necessary to change the physiology of the fish to cope with the stress and turn off various genes that control unnecessary bodily functions during stressful times (like growth or reproduction). This up- and down- regulation of proteins is a key to Dr. Kelley’s research.
Alternatively, a proteomics map shows all proteins expressed in a given tissue, and each protein has its own specific position in the map. This allows the team to screen for proteins that may be abnormally elevated or depressed in tissue samples. By lining up the proteome map of a test fish with the proteome map of a reference fish from a non-contaminated site, Dr. Kelley and his team are able to characterize the molecular and physiological effects associated with contaminant exposures and endocrine disruption. For example, if a male fish shows increased expression of egg proteins, then the environmental presence and action of an estrogen-mimicking chemical is indicated. Along with a panel of endocrine measures, the resulting protein expression changes can then be correlated with concentrations of contaminant chemicals that have accumulated in the tissue of the animals.
Dr. Kelley’s results have clear implications for state and regional environmental managers working toward effective ecosystem-based management. Traditionally, water quality objectives and monitoring have been based on measuring contaminant concentration alone and assuming risk often based upon limited published laboratory studies. But knowing that a contaminant is present in the water does not help managers understand if and how it is affecting wildlife. There is a critical need for a scientifically based understanding of the impacts of water quality on wildlife in the urban ocean habitats of coastal California, and Dr. Kelley’s research addresses this need. Further development of bioanalytical technologies such as endocrine and proteomic screening methods could allow these water quality agencies and managers to develop objectives in a more ecosystem-based manner by linking endocrine disruption and other important effects directly to the anthropogenic contaminants causing the disruption.
Naturally when discussing endocrine disruption, the issue inevitably arises of if and how the results apply to humans. The U.S. Environmental Protection Agency (EPA) is responsible for determining the possible threat of chemicals to the health of humans and wildlife and then establishing acceptable levels of exposure in the environment, including fresh and ocean waters. Because endocrine systems are similar in all animals with a backbone (including humans), identifying the effects of a new contaminant in fish will ultimately help in understanding environmental levels that are acceptable for humans. Dr. Kelley’s work provides an important first step in this direction. In addition, there is a large population of people, especially in Southern California, who use the public piers for subsistence fishing. USC Sea Grant is a partner of the Fish Contamination Education Collaborative, which, since 2003, has been working to protect the most vulnerable populations in Southern California from the health risks of consuming DDT- and PCB-contaminated fish. Dr. Kelley’s research expands upon these already known contaminants, shedding light on new contaminants affecting commercially and recreationally important species.
As more and more protein biomarkers are identified and added into a developing proteomics map screening method, it becomes increasingly powerful and valuable as a screening tool. From the perspective of an environmental manager, proteomics screening has the potential to provide for an assessment simultaneously of the expression of 100s to 1000s of proteins, revealing: the effects of trace contaminants that may fall below analytical chemistry detection limits; the synergistic effects of combinations of contaminants; the effects of contaminants of emerging concern; the effects of yet unknown (“new”) chemicals; and even the effects associated with environmental changes such as ocean acidification, hypoxic events, and changes in water temperature.
Visualizing the effects of stress caused by environmental conditions like pH and temperature may help fishery managers generate strong predictions of population and ecosystem effects associated with impending climate change. Using such adaptive, ecosystem-based management strategies are an important goal of the state, especially for economically important fishery species. Perhaps this screening technology would also be useful in monitoring the effects of negatively impacted water quality on marine resources protected by California’s new network of marine protected areas (MPAs) established under the Marine Life Protection Act (MLPA).
This emphasis on scientific research that has direct and immediate implications for environmental management is the hallmark of OPC/Sea Grant funded work. One of the greatest aspects of Dr. Kelley’s work is that it has provided a real-time, direct link between academic science and the regulatory community by collaborating with Dr. Jeffrey Armstrong, Environmental Supervisor at the Orange County Sanitation District (OCSD). “Our collaborations with Dr. Kelley and his students have given us valuable information about potential effects from our discharge that we would have missed otherwise,” says Dr. Armstrong. “Plus, his work in other areas of Southern California allow us to put our results into a regional context which is very helpful from a potential regulatory perspective.”
Dr. Kelley also collaborates with a very active nonprofit organization called the Pacific Coast Environmental Conservancy (PCEC), which focuses on environmental contaminants and their effects, and, importantly, has a unique, strong education and outreach component reaching into low-performing, inner-city Los Angeles schools. PCEC was started by Jesus Reyes, one of Dr. Kelley’s previous graduate students (interviewed in the Getting Underway section of this issue), who recognized a need for people in these low income communities, many of whom fish for subsistence from public piers, to understand the impacts of human activity on the health of fish. With the assistance of the Kelley Lab, Jesus Reyes and PCEC are able to take school children out sampling so they can learn the science first hand.
Reaching even farther into the world of public education, Dr. Kelley has partnered with the Cabrillo Marine Aquarium in San Pedro, California to provide the foundation and guidance for a new public exhibit opening September 2013 called “Pollution in our Sea – What Happens to the Fish?” This exhibit will address the entry of contaminants like pharmaceuticals and personal care products into the ocean and explain how they then impact fish health (and by extension, us). The exhibit will feature the concept of “environmental endocrine disruption” and the role of good conservation and personal behavior practices in terms of trying to reduce this threat to coastal health. "We are grateful for the opportunity to be able to share the results of Dr. Kevin Kelley's Sea Grant-OPC funded research,” says Dr. Julianne Kalman Passarelli, co-investigator and Exhibits Curator at the Aquarium. “These findings will be useful to help us inspire our aquarium visitors to take better care of our local ocean." Also, a web portal is being developed for conservation, under which one of the four main topics is “pollution.” The portal will link to state agencies, laboratories, and technical information. In addition to this exciting exhibit, Dr. Kelley and his students participate in ongoing Cabrillo Marine Aquarium outreach through public lecture series and K-12 beach surveys.
So often we find that academic research, environmental management, and public education operate in separate spheres. It is rare to find an academic researcher like Dr. Kevin Kelley who not only is producing novel and exciting work in his field, but also reaching across the divide to actively and concurrently involve environmental managers, policymakers and even the public in his work. USC Sea Grant and the California OPC are proud to have supported the research, outreach and students of Dr. Kelley and look forward to seeing more of his work in the future.
The close link of this type of research to human health makes this kind of work extremely important and urgent. Infamous contaminants like DDT and PCBs have not been produced in the U.S. for almost twenty years, and yet their legacy, especially in locations of high production like Southern California, will continue for some time as they slowly leech from contaminated ocean sediments. However, there may be new chemicals invented within the last decade (or will be invented in the near future) that we may still have time to identify and discontinue use before they become legacy environmental contaminants and known endocrine disruptors. Work like Dr. Kelley’s will help us identify these new contaminants, figure out their effects, and hopefully make changes before it is too late.
More information: www.cabrillomarineaquarium.org; www.PCEConservancy.org