Concentrations of lead and mercury in multimedia samples from homes near the former Clark Air Base, Philippines

Tracking quicksilver: estimation of mercury waste from consumer products and subsequent verification by analysis of soil, water, sediment, and plant samples from the Cebu City, Philippines, landfill

Source attribution of mercury (Hg) is critical for policy development to minimize the impact of Hg in wastes. Mercury content of consumer products and its subsequent release into the waste stream of Cebu City, Philippines, is estimated through surveys that employed validated, enumerator-administered questionnaires. Initially, a citywide survey (n = 1636) indicates that each household annually generates 1.07 ppm Hg (i.e., mg Hg/kg waste) and that linear and compact fluorescent lamps (17.2 %) and thermometers (52.1 %) are the major sources of Hg. A subsequent survey (n = 372) in the vicinity of the city's municipal solid waste landfill shows that residents in the area annually generate 0.38 ppm Hg per household, which is less than the citywide mean; surprisingly though, less affluent respondents living closer to the landfill site reported more Hg from thermometers and sphygmomanometers. Analysis of collected soil (0.238 ppm), leachate water (6.5 ppb), sediment (0.109 ppm), and three plants (0.393 to 0.695 ppm) shows no significant variation throughout five stations in and around the landfill site, although the period of collection is significant for soil (P = 0.001) and Cenchrus echinatus (P = 0.016). Detected Hg in the landfill is considerably less than the annual estimated release, indicating that there is minimal accumulation of Hg in the soil or in plants. As a result of this project, a policy brief has been provided to the Cebu City council in aid of hazardous waste legislation.

Metal sources and exposures in the homes of young children living near a mining-impacted Superfund site

Children living near hazardous waste sites may be exposed to environmental contaminants, yet few studies have conducted multi-media exposure assessments, including residential environments where children spend most of their time. We sampled yard soil, house dust, and particulate matter with aerodynamic diameter <2.5 in 59 homes of young children near an abandoned mining area and analyzed samples for lead (Pb), zinc (Zn), cadmium (Cd), arsenic (As), and manganese (Mn). In over half of the homes, dust concentrations of Pb, Zn, Cd, and As were higher than those in soil. Proximity to mine waste (chat) piles and the presence of chat in the driveway significantly predicted dust metals levels. Homes with both chat sources had Pb, Zn, Cd, and As dust levels two to three times higher than homes with no known chat sources after controlling for other sources. In contrast, Mn concentrations in dust were consistently lower than in soil and were not associated with chat sources. Mn dust concentrations were predicted by soil concentrations and occupant density. These findings suggest that nearby outdoor sources of metal contaminants from mine waste may migrate indoors. Populations farther away from the mining site may also be exposed if secondary uses of chat are in close proximity to the home.

Indoor air concentrations of mercury species in incineration plants for municipal solid waste (MSW) and hospital waste (HW)

Until now, there is limited information about mercury exposures inside solid waste incineration plants although incineration has been considered as one of major solid waste treatments. This study investigated indoor air concentrations of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particulate mercury (Hgp) and indoor dust mercury concentrations in a municipal solid waste incineration (MSWI) plant and a hospital waste incineration (HWI) plant during December 2003 and July 2004. The final results showed that the employees in incineration plants are not only exposed to GEM, but also to RGM and Hgp. For the HWI plant, only concentration of total mercury (HgT) in operation center in summer was below 1000ngm(-3) due to frequent ventilation, while those of GEM and HgT in hospital waste depot exceeded 3000ngm(-3). For the MSWI plant, only concentration of HgT in workplace in winter exceeded 1000ngm(-3). Therefore, more attention should be paid to mercury exposures in HWI plants than in MSWI plants. Indoor dust containing approximately 3968microgHgTkg(-1) (dry matter) possibly served as the potential source for indoor air mercury pollution, especially in the HWI plant.