Throughout the United States, anthropogenic pollutants increasingly compromise our nation's waterways; and waterborne diseases continue to be major source of morbidity worldwide. By studying chemicals, aquatic macro-organisms, pathogenic bacteria, viruses, and protozoa using multidisciplinary approaches we can begin to understand their fate and ecology in aquatic ecosystems. This information can be used to model water quality and protect public heath.
Aquatic organisms are excellent sentinels of water quality, as they are more intimately associated with water-borne pollutants and exposed to higher pollutant concentrations than are humans. Biological markers of effect developed in the laboratory and validated in the field by EHS researchers are tools for identifying and understanding transport and fate of chemical and microbiological pollutants. Surveys of aquatic fauna that include physiological, biochemical and histopathological assays are correlated with environmental contaminant levels, land use characteristics, or other measurements of environmental impairment to assess water quality and the potential for impacts to human health. Current projects in this field of study include:
- Fate and toxicity of pharmaceuticals (specifically the selective serotonin reuptake inhibitors--Prozac, Zoloft, Paxil, Luvox and Celexa) in the aquatic environment.
- In-situ assessment of small, headwater streams impacted by suburban pesticide runoff.
- Impacts of urban land use on resident fish health parameters, and correlations with land use metrics.
- Potential causes for the disappearance of largemouth bass in the Okefenokee Swamp.
- Assessing mine-related heavy metal toxicity in the Tisza River, Hungary.
- Impact and role of climate change and weather on waterborne pathogens and disease (specifically evaluating storm and drought effects on waterborne salmonella and campylobacter levels).
- Interaction between waterborne pathogens and marine/estuarine organisms (i.e., do organisms such as algae, zooplankton (crustaceans), coral, sponges, etc. Harbor human pathogens and affect how they are transmitted to humans?).
- Impact of domestic wastewater treatment/disposal practices (septic tanks, ocean
wastewater outfalls, etc.) On offshore marine water quality.
Expectant parents worldwide share the same hope: to have normal healthy babies. Research in the EHS Department includes projects designed to understand the mechanisms and effects of exposure to chemicals and biological agents that can cause morbidity and mortality in children and pregnant women. Such reproductive and developmental toxicants include common pesticides present in multiple environmental media and pathogens that can occur in food. For example, infectious agents such as the microbe Listeria monocytogenes are known to cause important adverse effects ranging from low birth weight to mortality. Some of the current projects in this area are listed below. Other research related to child and maternal health is described in the Developmental Toxicology section.
Current projects related to child and maternal health include:
- Infectious Agents
- Establish a valid animal model for effects of infectious agents on pregnancy and development.
- Identify immunological markers of exposure to infectious agents that can be used to develop effective treatment strategies.
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Effects of pesticides and air pollution of pregnancy
- Measurements and models of longitudinal, multiple media, and multiple chemical exposure to non-persistent insecticides by children and expecting mothers.
- Relationship between ambient particle exposures and pediatric asthma in Atlanta in collaboration with Emory University and Georgia Tech.
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Develop dose response data to support risk assessments for pregnancy and development.
The type, magnitude, and mechanisms of effects of chemical and biological pollutants on human and other organisms constitute the domain of environmental toxicology. Faculty, fellows, staff, and graduate students in the EHS Department conduct basic and applied research in environmental toxicology.
Laboratory-based projects in the EHS Department include ascertaining the mechanisms by which chemical toxicants cause developmental effects such as disrupted growth and differentiation of developing systems, use of the nematode Caenorhabiditis elegans as a toxicological screening method for mammalian and human systems. Potential ecological effects of industrial chemicals and pharmaceuticals on fish, invertebrates and bivalves are investigated in laboratory exposures with standard aquatic test organisms such as selected zooplankton and alternative test species such as freshwater bivalves and fish.
Environmental toxicology research results are essential inputs to risk assessments and eventually risk management decisions designed to balance protection of public health and economic development. For example, EHS researchers work in the field of computational toxicology to bridge basic toxicological data for test animals to potential effects on humans and other sensitive receptors. In addition, research is conducted to develop dose-response information for infectious agents and mixtures of chemicals that can be used by regulatory agencies to assess risk and develop public health policy.
Exposure Assessment and Environmental Epidemiology
Environmental epidemiology is the study of human disease in relation to factors in the environment. Assessment of exposure to environmental agents for populations and individuals is an essential component of environmental epidemiology. The potential effects of air pollutants and pesticides are the focal points of exposure and epidemiological research in the EHS Department. By understanding the health risks of exposure to these chemicals, we can identify those that impair public health in a meaningful way. By understanding the sources and pathways of exposure to complex pollutants that are present in multiple environmental media, we can develop effective strategies for reducing health risks.
The potential effect of hazardous chemical and physical agents in occupational settings is a special application of exposure assessment that is critical to public health and economic development in the United States and the world. EHS researchers are engaged in a number of studies that relate to occupational health and support the department's academic curriculum in industrial hygiene. Current exposure assessment and environmental epidemiology projects include:
- Dietary intake of pyrethroid and organophosphate insecticides by children and relation to biomarkers of exposure.
- Organophosphate pesticide exposure levels in children of Jacksonville, FL.
- Lindane and permethrin urinary metabolites in children being treated for ectoparasites in Dawson and Forsythe County, Georgia.
- Smoke particulate exposures and health effects related to prescribed fires in Georgia forests for fire fighters.
- Personal and occupational exposures to air pollutants from motor vehicle emissions in Peru.
- Cytokine production by alveolar macrophages and dendritic cells exposed to ambient and source-specific particulate matter.
- Chemical and physical stressors in the coal-fired electric power industry.