Airborne emissions of mercury from municipal solid waste. II: potential losses of airborne mercury before landfill.
Waste distribution and compaction at the working face of municipal waste landfills releases mercury vapor (Hg(o)) to the atmosphere, as does the flaring of landfill gas. Waste storage and processing before its addition to the landfill also has the potential to release Hg(o) to the air if it is initially present or formed by chemical reduction of Hg(II) to Hg(o) within collected waste. We measured the release of Hg vapor to the atmosphere during dumpster and transfer station activities and waste storage before landfilling at a municipal landfill operation in central Florida. We also quantified the potential contribution of specific Hg-bearing wastes, including mercury (Hg) thermometers and fluorescent bulbs, and searched for primary Hg sources in sorted wastes at three different landfills. Surprisingly large fluxes were estimated for Hg losses at transfer facilities (approximately 100 mg/hr) and from dumpsters in the field (approximately 30 mg/hr for 1000 dumpsters), suggesting that Hg emissions occurring before landfilling may constitute a significant fraction of the total emission from the disposal/landfill cycle and a need for more measurements on these sources. Reducing conditions of landfill burial were obviously not needed to generate strong Hg(o) signals, indicating that much of the Hg was already present in a metallic (Hg(o)) form. Attempts to identify specific Hg sources in excavated and sorted waste indicated few readily identifiable sources; because of effective mixing and diffusion of Hg(o), the entire waste mass acts as a source. Broken fluorescent bulbs and thermometers in dumpsters emitted Hg(o) at 10 to >100 microg/hr and continued to act as near constant sources for several days.
Southworth
George R
GR
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6036, USA. Southworthgr@ornl.gov
Lindberg
Steve E
SE
Bogle
Mary Anna
MA
Zhang
Hong
H
Kuiken
Todd
T
Price
Jack
J
Reinhart
Debra
D
Sfeir
Hala
H
D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring; D008628:Mercury / Q000032:analysis*; D012037:Refuse Disposal; D014835:Volatilization
D000393:Air Pollutants; D008628:Mercury