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Previous by Date: Subject: Amorphous silicone dioxide silica Date: Fri, 6 Mar 2009 18:10:38 +1100 Author: Paul Dover |
Next by Date: Subject: Re: Amorphous silicone dioxide silica Date: Sat, 7 Mar 2009 08:58:06 -0500 Author: Chrismarlowe |
Paul - There are two distinct types of silica, crystalline and amorphous silica. They differ significantly in the health effects they cause when inhaled. B oth crystalline silica and amorphous silica incite pulmonary inflammation, but significantly, only inhalation of crystalline silica ultimately leads t o the development of pulmonary fibrosis (i.e. silicosis). It is unclear wh y there is such a difference in the pathological outcome. Possibly due to the physical properties of amorphous and crystalline silica. When inhaled crystalline silica particles are ingested by alveolar macrophages, the macr ophages are activated and damaged, resulting in ongoing injury and ultimate ly leading to the development of silicosis. In contrast, amorphous form of silica has a far larger surface area and hence a greater relative solubili ty within the lung, enabling it to be cleared more easily following inhalat ion. So back to your original question - I would not have an issue with the 25 k g containers versus the 1 kg container - as long as it is amorphous silica and the handling is not generating a significant exposure to nuisance dust. Best Regards, Brian M. Spears, CIH, CSP, CHMM Associate Industrial Hygiene Specialist Safe Work IS Our Job Dow Corning Corporation 4770 Highway 42 East Carrollton, KY 41008 office: (502) 732-2726 mobile: (502) 682-8593 -----Original Message----- From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**list.uvm.edu] On Behalf Of Pa ul Dover Sent: Friday, March 06, 2009 2:11 AM To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Subject: [DCHAS-L] Amorphous silicone dioxide silica G'day all, Can I get some opinions/advice please? Our HOD got 25kg drums of this stuff for each lab, Davisil LC60A 40-63 (um) LOW to be precise. We just had an OHS inspection and the consultant was unimpressed and suggested in future we get 1kg containers. We used to do this, but the HOD noted cost 25kg was only three times cost of a 1kg container...and we go through it. Anyway, in lieu of that we were told risk assessments, SOP for transfer, etc., required. No argument from me, silicosis is a nasty thing. I call up the MSDS and to my great surprise it is Hazard alert: NIL, Non Hazardous Substance, Non Dangerous Goods. Smug head of department feels vindicated in his choice to get 25kg drums of the stuff. I'm not so sure. I'll still get risk assessment and SOP, but what do I say next time he wants to order in bulk!? Cheers, Paul ____________________________________________ Paul Dover Resources Manager Medicinal Chemistry and Drug Action Monash Institute of Pharmaceutical Sciences Monash University (Parkville Campus) 381 Royal Parade, Parkville Victoria, 3052. Australia Phone: +61 3 9903 9551 Fax: +61 3 9903 9143 Email: Paul.Dover**At_Symbol_Here**pharm.monash.edu.au Web: http://www.pharm.monash.edu.au
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