Human Health Focus Group
Meeting #4
June 15, 2007
Notes taken by Jordan Palmeri
▪ Sue MacMillan was the only group member not present
▪ FG discussed need to provide an introduction to risk which could include
o What is it? We’re talking about Human Health…
o How is it assessed?
o Cancer/ Non cancer
o Toxicity
o Show dose/response curve
▪ We could use the WQS module to help us for some of the presentation
▪ To introduce the straight equations would be daunting
▪ We should illustrate the criteria equations to make it easier to understand
▪ We need an acceptable way to present risk / maybe we can work with the risk triangles that explain the different types of risk people face all the time…driving your car…etc…
▪ We need to discuss the philosophy of risk as well…there is a broader meaning of risk…there is a cultural significance as well
▪ Discuss that many different things can be harmful, it all depends on the dose
▪ Mercury is naturally occurring and that can be used as an example of something that poses a natural risk
▪ Put the lifetime cancer risk into perspective for people – 1 out of 3 people can develop cancer in their lifetime. There are many causes of cancer and simply eating fish is not people only exposure pathway.
▪ There are, however, certain individuals where their exposure to contaminants through fish is their main exposure pathway for cancer causing chemicals
▪ Cancer is common, but this project is relevant because we can do something about the amount of cancer causing chemicals that are considered acceptable
▪ Here’s how some of the slides can go for the presentation:
o Talking about human health risk only
o Multiple types of risk
o What do we mean by risk
o Dose response curves
o Dose response different for cancer and non cancer
o Acceptable limits (cancer/non)
o Philosophy of risk
o Exposure
o Equations
o Background and RSC
o Pathways
o Show thresholds
o Non cancer – show neurodevelopment, use an epidemiological study
o Show an example like lead (use a neurotoxin)
o Shifting IQ??
▪ Carcinogen – lots of variation on how people treat carcinogens
▪ In Commencement Bay, if a child ate 1 crab they were over the cancer risk
▪ We usually put more emphasis on the noncancer aspects
▪ Some controversy in the EPA fish contaminant study about why EPA added carcinogens together
▪ Dose response models are predictions
▪ We rely on test methologies and then extrapolate to people…there are uncertainties
▪ We need to list assumption because it’s easy to over or underestimate risk
▪ Additivity – this is a concern
▪ RSC assumptions – we need to list these out
▪ RSC not applied to linear cancer model
▪ FG did not seem to completely agree on EPAs use of the RSC but the discussion was not brought too far and it needs to continue…
▪ Equation assumptions
o No consideration of background cancer rates
o RSC – does not include multiple endpoints…only calculated for one chemical at a time and does not take the exposure from other chemicals that have the same endpoint into account in the RSC…this could be seen as a deficiency in the EPA method
o All values come from IRIS …this depends on the last time EPA updated their criteria as to the whether the values are current with the IRIS values today
o Mixed of chemicals that have the same endpoint are not considered together
▪ We need to relate grams/day to ounces of fish
▪ Spell out the equations (do an actual calculation) so people could follow in detail
▪ Hazard Quotient – when above, you really have no idea what will happen. EPA policy says that the hazard quotient should not be exceeded.
o When exceeded it is difficult to compare a value of 10 to 100 because the potency of the chemicals may be very different making the direct comparison of the numeric HQs not applicable
o Can’ really quantify b/c each chemical has a different potency/severity of effect
o The group needs to explain why it can’t really be quantified in the public workshop…have this discussion
▪ Low level exposures to human populations…we’re still trying to figure out all the effects…not an easy task
▪ We may want some sort of team building as part of Q and A discussion in the workshop
▪ Give workshop participants the option to submit their comments on notecards so we can get back to them with answers if there is not time in the workshop
▪ It’s important to note that the group is still in the middle of discussions and it’s OK to say we’ll get back to you when people ask certain types of questions at the workshops
▪ By 6/21 everyone will email their ideas, notes, and slides about the presentation to Jordan and he will take a rough cut at putting a presentation together for the group