111. Risk assessment, management, and communication

From greek.doctor
  • Risk assessment
    • = assessing the health risk of a policy, action, or intervention
    • Involves:
    • Identification of the hazard
    • Evaluation of the dose-response relationship
      • Compounds can follow a deterministic dose-response relationship or a stochastic dose-response relationship
      • Deterministic dose-response relationship
        • = means that as the dose is increased past a certain threshold (LOAEL), the severity of the effect increases
        • Most compounds have this type of relationship
        • The highest dose at which there is no observed effect is the NOAEL (no observed adverse effect level)
        • The lowest dose at which there is an observed effect is the LOAEL (lowest observed adverse effect level)
      • Stochastic dose-response relationship
        • = means that there is no safe dose threshold, and as the dose increases the probability (not the severity) of the effect increases
        • Even at an exposure of 1 molecule, the adverse effect can occur (albeit with extremely low probability)
        • Carcinogenic compounds have this type of relationship
        • There is no upper limit of safe dose, so instead we use the ALARA principle (as low as reasonably achievable)
    • Evaluation of human exposure
      • Estimate concentration in the environment
      • Perform measurements of the environment and biological samples
        • Many chemicals have biomarkers which can be measured in the urine
    • Characterization of the risk
      • The unit of risk is microrisk (µR)
        • 1 µR refers to one case of adverse effect per 1 million people
      • The highest acceptable risk for the general population is 1 µR/life
      • The highest acceptable risk for the working population is 10 µR/year
        • Because the working population is overall healthier than the general population
      • Reference dose (RfD) = (NOAEL or LOAEL) / (UF1 x UF2 x … x MF)
        • RfD is the maximum acceptable dose to be exposed to
        • This formula allows for extrapolation of results from animal studies to humans
        • UF and MF are uncertainty factors
  • Risk management
    • = planning and implementation of actions to reduce or eliminate health risk
    • Preventative measures (in sequence)
      • Improve manufacturing practice
        • For example, change the manufacturing process to one with less risk
      • Use better working tools
      • Use less hazardous chemicals
      • Collective safety
      • Rearrange work
        • Decrease working hours
      • Use personal safety equipment
        • This should only be used is all other measures fail
        • This is because workers tend to not use safety equipment correctly (because they’re uncomfortable), so it’s not an effective way of preventing risk
  • Risk communication
    • = communicating the risk to the exposed people