Current and historical record of indium deposition from the atmosphere to an ombrotrophic bog in northeastern United States
Abstract
The industrial production of indium is increasing dramatically due to new uses in the rapidly growing electronics, photovoltaic, and LED industries. Little is known, however, about the natural or industrial cycling of indium or its environmental behavior, despite the fact that industrial emissions to the atmosphere appear to have already exceeded natural emissions. The history of metal deposition from the atmosphere is often reflected in the vertical profiles of the metals in ombrotrophic bogs, which by definition do not receive surface or subsurface runoff. Analysis of a peat core obtained using a novel freeze corer at Thoreau's Bog in Concord, MA shows that the rate of indium deposition to the bog increased beginning in the early 1900s, peaked in the early 1970s, and then decreased dramatically to pre-1900 values by the present time. This profile is counter to the pattern of indium's industrial use, which has increased only in the past 30-40 years. The profile coincides well, however, with the estimated history of particulate emissions from smelting and from coal combustion in North America. Back-trajectory analysis suggests that smelting was the dominant source of atmospheric particles with high indium concentrations deposited to the bog. This study suggests that metal smelting and coal burning are currently indium's primary industrial environmental sources. While releases from the semiconductor and electronics industries are comparatively small at present, this scenario may change with the rapid growth of indium use in these industries.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.H13E1404W
- Keywords:
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- 0414 BIOGEOSCIENCES / Biogeochemical cycles;
- processes;
- and modeling;
- 0461 BIOGEOSCIENCES / Metals;
- 0478 BIOGEOSCIENCES / Pollution: urban;
- regional and global;
- 1890 HYDROLOGY / Wetlands