Exposure to lead and other toxic metals from informal foundries producing cookware from scrap metal.

Metal exposure remains a significant public health problem, particularly in the informal sector. The rise in informal foundries to cast scrap metal into artisanal cookware is widespread in low- and middle-income countries. The main aim of this study was to characterize metal exposure in artisanal cookware makers working in informal foundries in South Africa by measuring lead (Pb) in blood as well as sample metal concentrations on hands before and after work. The blood Pb distribution of the artisanal pot makers ranged from 1.1 to 4.6 µg/dl with the median blood Pb level being 2.1 µg/dl (IQR 1.7-2.5). The median blood Pb level in artisanal pot makers was 1.0 µg/dl higher compared with the non-exposed community members (p < 0.0001). Before-and-after handwipe sampling revealed a median increase in all 22 elements. Pre and post aluminum (Al) load on the handwipes revealed a 7.3 factor increase (0.53 and 3.9 mg Al/handwipe respectively) (p = 0.003). Hand Pb load before and after pot making revealed a 3.5-fold increase (median increase of 6.2 µg Pb/handwipe). An increase in backyard informal foundries may be linked to increased exposure to toxic metals for workers, family members and communities.

Mineralogical and geochemical characterization of waste rocks from a gold mine in northeastern Thailand: application for environmental impact protection.

Waste rocks from gold mining in northeastern Thailand are classified as sandstone, siltstone, gossan, skarn, skarn-sulfide, massive sulfide, diorite, and limestone/marble. Among these rocks, skarn-sulfide and massive sulfide rocks have the potential to generate acid mine drainage (AMD) because they contain significant amounts of sulfide minerals, i.e., pyrrhotite, pyrite, arsenopyrite, and chalcopyrite. Moreover, both sulfide rocks present high contents of As and Cu, which are caused by the occurrence of arsenopyrite and chalcopyrite, respectively. Another main concern is gossan contents, which are composed of goethite, hydrous ferric oxide (HFO), quartz, gypsum, and oxidized pyroxene. X-ray maps using electron probe micro-analysis (EPMA) indicate distribution of some toxic elements in Fe-oxyhydroxide minerals in the gossan waste rock. Arsenic (up to 1.37 wt.%) and copper (up to 0.60 wt.%) are found in goethite, HFO, and along the oxidized rim of pyroxene. Therefore, the gossan rock appears to be a source of As, Cu, and Mn. As a result, massive sulfide, skarn-sulfide, and gossan have the potential to cause environmental impacts, particularly AMD and toxic element contamination. Consequently, the massive sulfide and skarn-sulfide waste rocks should be protected from oxygen and water to avoid an oxidizing environment, whereas the gossan waste rocks should be protected from the formation of AMD to prevent heavy metal contamination.

Opacification of a silicone intraocular lens caused by calcium deposits on the optic.

We describe opacification of a plate-haptic silicone intraocular lens (IOL) caused by calcification in a diabetic patient with asteroid hyalosis. The IOL was explanted 48 months after uneventful phacoemulsification because opacification of the posterior surface was causing significant visual disturbance. Light and scanning electron microscopy and x-ray spectrometry of the explanted IOL showed the opacification consisted mainly of calcium and phosphate, presumably hydroxyapatite, in the form of precipitations on the posterior surface of the optic.