Eco-epidemiological modelsEcological Epidemiology or Eco-Epidemiology is the study of both the chemical and physical nature of the environment, examining how together they contribute to the health of the ecosystem.
Scientists who study the environment know that all organisms are connected in the web of life. If a chemical affects some organisms, other organisms in the ecosystem may suffer since all organisms depend on one another.

  • Eco-epidemiology’s field of study

    Eco-epidemiology Ecosystem health

    The field of eco-epidemiology is very broad. If scientists consider a river, they need to know the type of organisms in the aquatic community, the river flow speed, its size, depth and water temperature, the type of river bed… and then they begin to factor in the potential chemical changes.
    Research is done to understand how the chemistry of the environment affects the health of aquatic communities. Questions included:

    • there many toxic chemicals?
    • is the pH in the right range?
    • are nutrient concentrations too high?
    • are there too many suspended solids?
    As the environment has become cleaner, scientists have realized that we also need to better understand the physical environment to make additional improvements to our ecosystem. This is especially true for flowing water systems (rivers, streams, creeks). Physical factors in the river that affect the number and type of species present include:
    • river size,
    • river flow,
    • river temperature, and,
    • the type of bottom (sand, rock, etc.).

    All of these factors play a role in defining what organisms and how many are present in the river. Changes in the chemical or physical nature of a site can impact the fish, algae and invertebrates that live there. Studying both the chemical and physical nature of the environment and how they both contribute to the health of the ecosystem is ecological epidemiology or eco-epidemiology.
    P&G is helping to lead this relatively new science (see Eco-epidemiology publications listed below).

  • Eco-epidemiological models and findings

    P&G scientists use a variety of environmental models to understand the concentration of consumer products in the environment. Some of these computer models use Geographic Information Systems (GIS) to combine information on chemistry, ecology and the physical environment (e.g., river flow, river depth) to give us a clearer picture of the river. Ideally, we want to better understand if the ecosystem is responding to degradation in the physical or chemical environment. GIS software allows the user to study data for a specific site in a river.

    For example, we can get river flow, chemistry and biology data all for the same location. The real power of GIS is that we can do this analysis for hundreds or thousands of sites in the country we are interested in, and we can overlay dozens of different types of data at each site to determine which factors control ecosystem health.
    In a study of the entire state of Ohio, USA, P&G researchers found that river size and local habitat (e.g., amount of "cover," which includes large rocks, logs and other places for fish to hide) were important for healthy communities. However, the percentage of effluent was consistently identified as the most prominent negative factor addressing impacts. Further, effluents in urban areas caused greater damage than effluents in rural areas.
    Because consumer product ingredients are present at roughly the same concentration in urban and rural effluents, we do not expect these ingredients to be responsible for the effect observed. However, much more research is needed and P&G's efforts are continuing.

  • Publications

    • Dyer, S.D. and Wang, X., 2002. A Comparison of Stream Biological Responses to Discharge from Wastewater Treatment Plants in High and Low Population Density Areas. Environmental Toxicology and Chemistry, 21, pp.1065-1075.
    • Dyer, S.D. and White-Hull, C.E., 1999. Current Risk Assessments Overpredict Environmental Effects from Municipal Effluents. Watershed and Wet Weather Technology Bulletin, 4, pp. 3-6.
    • Dyer, S.D. and White-Hull, C.E, 1998. Eco-Epidemiology: Predicted Risk and the Real World. Proceedings from Watershed Management: Moving from Theory to Implementation. Denver, CO, May 3-6. Pp. 1129-1134.
    • Dyer, S.D., White-Hull, C.E., Carr, G.J., Smith, E.P., and Wang, X., 2000. Bottom-Up and Top-Down Approaches to Assess Multiple Stressors over Large Geographic Areas. Environmental Toxicology and Chemistry, 4, pp.1066-1075.
    • Dyer, S.D., White-Hull, C.E., and Shepherd, B.K., 2000. Assessments of Chemical Mixtures via Toxicity Reference Values Overpredict Hazard to Ohio Fish Communities. Environmental Science and Technology, 34, pp. 2518-2524.
    • Dyer, S.D., White-Hull, C.E., Wang, X., Johnson, T.D., and Carr, G.J., 1998. Determining the Influence of Habitat and Chemical Factors on Stream Biotic Integrity for a Southern Ohio Watershed. Journal of Aquatic Ecosystem Stress and Recovery, 6, pp. 91-110.
    • Peng, C., Jung, K., Arakaki, T., Dyer, S.D., White-Hull, C.E., and Wang, X., 2000. Development of a Geographic Information System for Environmental Risk Assessment in Asia: Linking Sewage Infrastructure with River Models, Chemistry and Biology. Proceedings of the Second International Symposium on Advanced Environmental Monitoring. Cheju Island, Korea, Oct. 31-November 2, 2000.
    • Wang, X., White-Hull, C., Dyer, S., and Yang, Y., 2000. GIS-ROUT: A River Model for Watershed Planning. Environmental Planning B: Planning and Design, 27, pp. 231-246.

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