tag:blogger.com,1999:blog-4705097374441454471.post672091976466730396..comments2024-03-28T08:51:15.561-04:00Comments on Human Health Risk Assessment to Chemicals: To Measure (or Estimate) Skin Exposure or NotMike Jayjockhttp://www.blogger.com/profile/02521885327730438390noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-4705097374441454471.post-36997418427500010742015-07-22T10:48:23.900-04:002015-07-22T10:48:23.900-04:00Perhaps what we need to recognise is that models a...Perhaps what we need to recognise is that models and exposure measurement techniques have their uses, but that from a practical perspective they could end up being rather lengthy processes if they were used for each and every chemical found in most workplaces and the varied uses they can be put to. There are situations where they are invaluable tools, but there value is only equal to our understanding of their limitations. If those using these tools do not understand their limitations, action can be taken that makes the situation worse rather than better. Prof Ronald Marks, a very eminent dermatologist and founder/expert in the field of skin measurements, once told me that "a fool with a tool is still a fool". It should also be mentioned that whilst uptake through the skin of chemicals that can cause systemic damage is without a doubt important we must not forget the significance of direct irritant damage to the skin both in the effect on the skin and the individual through irritant contact dermatitis but also in the affect this can have both on the ability of chemicals to penetrate the skin and their ability to cause type 4 sensitisation. The variability of individuals in their reaction to irritants is highly variable. In short models and measurement techniques have their uses and we should not stop trying to find more effective tools/techniques, but if that is what we spend most of our time focusing on rather than eliminating or reducing exposure then perhaps we should not be so surprised when the effects of skin exposure do not reduce as we would like them to.Helen Taylornoreply@blogger.comtag:blogger.com,1999:blog-4705097374441454471.post-13567717006207333162015-07-19T17:23:41.052-04:002015-07-19T17:23:41.052-04:00I don’t understand Chris' bleak view on the ut...I don’t understand Chris' bleak view on the utility of models. This is an area of active research and models are already available that can reliably predict systemic exposure from skin deposition for a wide variety of chemicals. This reminds me of the view some folks had toward PBPK models a few years back. The models were mathematically complex by the standards of the day, required large numbers of parameters, and the feeling was that if good values were not available for the parameters, the models were a waste of time. This essentially amounts to saying “no information is better than some information.” And this ignores the fact that even incomplete or partially parameterized models can be used to quantify uncertainty, explore sensitivity of model outputs to inputs, inform us of critical data needs, or predict extreme cases.Conrad Housandhttp://www.admewb.comnoreply@blogger.com