A two part study was conducted to investigate the surface properties of of the quartz (14808607) or "free silica" fraction of respirable mine dusts. The degree of surface contamination of respirable quartz particles was studied using scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDX to distinguish alumino/silicate and magnesium silicate surface occlusions from the silicate particles. By varying the electron beam accelerating voltage, the depth of penetration could be reduced, so that the surface layer could be distinguished from the substrate material. Experiments were conducted on the relationship of measured SEM-EDX signal coming from the substrate to coating thickness and electron beam accelerating voltage. In the second part, modifications were made of respirable quartz particle cytotoxicity by surface treatment. As measured by erythrocyte hemolysis and pulmonary macrophage release of lactate dehydrogenase in-vitro, respirable quartz cytotoxicity was neutralized by boiling in water in glass test tubes for 10 to 40 minutes. The membranolytic potential was reduced to near zero by boiling up to 10 milligrams of quartz per milliliter of water. Replacing the medium with fresh water midway through the boiling resulted in full detoxification. Preboiling the medium with silica reduced the effect. Detoxification persisted after mild drying at 110 degrees-C for 8 hours and persisted after 3 days of resuspension in water at room temperature.
Links with this icon indicate that you are leaving the CDC website.
The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
You will be subject to the destination website's privacy policy when you follow the link.
CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.
For more information on CDC's web notification policies, see Website Disclaimers.
CDC.gov Privacy Settings
We take your privacy seriously. You can review and change the way we collect information below.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
Cookies used to make website functionality more relevant to you. These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests.
Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data.
Cookies used to enable you to share pages and content that you find interesting on CDC.gov through third party social networking and other websites. These cookies may also be used for advertising purposes by these third parties.
Thank you for taking the time to confirm your preferences. If you need to go back and make any changes, you can always do so by going to our Privacy Policy page.