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Lecture 1 3 ss-1

Lecture 1 3 ss-1






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  • China - toys with paint containing lead.\n
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  • By injection or infusion - bypassing the usual route of ingestion or inhalation.\n
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Lecture 1 3 ss-1 Lecture 1 3 ss-1 Presentation Transcript

  • Entry and Fate of Chemicals
  • Inhalation Exposure► Most important route of entry of many biologic and chemical agents into the body.► Inhalation exposure per event is estimated based on:  Duration of each event  Inhalation rate of the exposed individual during the event  Concentration of the contaminant in the inspired air.► Airborne contaminants can be present in the:  Gaseous phase (gases and vapors)  Liquid phase (droplets)  Solid phase (particulates and fibers)
  • The Lungs Primary function is to take in oxygen and transport it to :1. the skeletal system2. the digestive system3. the circulatory system4. the endocrine system
  • Inhalation Exposure► Uptake of gases and vapors depends on:  Concentration and relative solubility of the agent in water and lipids► Depositionof particulates in the respiratory tract depends on:  Size, shape and density of the material► Hostfactors influencing uptake of gases and particulates include:  Age, weight, sex, race, disease state, respiratory rate.
  • Dermal Exposure► Dermal Exposure is determined by:  Concentration of hazardous substance in a contaminated medium that is contacted  Extent of contact  Duration of such contact► Factors influencing dermal absorption of chemicals include:  Molecular weight of the compound  Solubility in water (polar) or lipids (non-polar)  Presence of other compounds that might facilitate passage of a chemical through skin  Permeability of the skin► Dermal exposure takes place during:  Swimming or bathing in contaminated water  Skin contact with the soil and various industrial operations
  • Ingestion Exposure► Exposure due to ingestion of contaminated food (& drink) can be estimated as:  the product of contaminant concentration in the consumed food or drink.  the amount of food consumed per day.► Daily ingestion exposure estimates are calculated in the same manner, regardless of the type of ingested food.► In adults, ingestion exposure is mainly due to consumption of contaminated food and drinks► In children, ingestion exposure is mainly due to:-  consumption of soil  contaminated toys
  • This includes exposure to pets…► Last year over 50,000 calls involved the ingestion of human medications such as painkiller medications, antidepressants, and supplements. Your dog can snatch a vial off a counter or gobble up pills that accidentally hit the floor. So it is essential to keep this #1 hazard tucked away properly.► Also – veterinary medications, people food, pesticides, rodenticides, insecticides, household cleaners, & garden fertilizers.
  • Eye Exposure► Eyeexposure results from accidental contact of the eyes with:  Biologic agents  Chemical agents  Physical agents► Eyes are very sensitive and affected by minute amount of an agent.
  • Parenteral Exposure► Parenteral exposure is usually encountered as:  Bites and stings by animals  Occupational exposure among health professionals and veterinarians from cuts and pricks by sharp instruments (needles) contaminated with blood pathogens.  Illegal drug use – via needles
  • Recognition of Human Hazard Exposures1. Measure of actual exposure  Microenvironmental samplers ► e.g. passive samplers in homes or offices to measure airborne lead or Carbon monoxides  Personal monitor ► Active monitors worn by volunteers that measure real-time concentration  Biological measurements in human tissues or fluids ► Determine concentration in blood, urine, hair, saliva, sweat
  • Recognition of Human Hazard Exposures 2. Mathematical models  Mathematical abstractions of physical reality; create “models” based on mathematical analyses of smaller numbers of measurements  Three types of models used in Exposure Assessment 1. Concentration model – estimate concentration of pollutant in environmental media. 2. Contact model – estimate exposure or contact between pollution and persons. 3. Dose model – estimate the internal or delivered dose, or amount of pollutant that enters the body and that is finally deposited in specific human tissues and fluids.See World Health Organization: http://gamapserver.who.int/mapLibrary/
  • Recognition of Human Hazard Exposures3. Environmental exposure databases4. Sentinel (watching) event strategies5. Geographic information system (GIS)  Integrate diverse multimedia (air, soil, water) data, geographic features, census information, information about ecologic regions and chemical toxicity information into a common database with spatial characteristics
  • GIS remote sensing and graphical analysis http://nbii-nin.ciesin.columbia.edu/jamaicabay/maps.html Impervious Surfaces in the Jamaica Bay Estuary
  • Recognition of Human Hazard Exposures6. Biologic markers  Indicators of biological systems or samples  Once exposure has occurred, a continuum of biological events can be detected  Serves as markers of initial exposure, administered dose, biologically effective dose, and altered structure or function.
  • Biological Markers Biological Markers can represent:- ►Marker of effect (ex. glucose)  A change or rise in an internal substance that depending on it’s magnitude can be seen as a potential problem or disease ►Marker of susceptibility (presence of an allergen)  Indication of some sort of limitation or reaction to an external substance that is typically inherited ►Marker of exposure  The amount of substance that is found to have interacted with an organism.
  • Deposition of particulates in the respiratorytract depends on the _____, _____, and ____1. Lipid solubility, size, weight2. Water solubility, weight, shape3. Size, shape, density4. Shape, lipid solubility, water solubility
  • What is the #1 killer of inhaled material?► carbon monoxide► cigarette smoke► dust► pollen
  • Questions► How are gases formed from landfills?► What is the most common type of landfill?► If you live near a landfill, is landfill gas hazardous to your health? If so, in what ways?► What are the Federal regulations and laws to protect people and how are they enforced?