Litterfall Mercury Monitoring Network
Litterfall is leaves, needles, flowers, fruit, and debris found on the forest floor. Litterfall sampling can be an effective tool for monitoring elements like Mercury. Mercury in litterfall is primarily from the atmosphere and contributes to the higher amounts of mercury dry deposition that accumulates in forested areas compared to non-forested areas.
INKY scientists collect litterfall as part of the National Atmospheric Deposition Program (NADP) as well as provide litterfall sampling kits to NADP site operators who ship monthly samples back to USGS. The USGS Mercury Research lab analyzes the samples and reports the data to NADP.
Click on the Science tab above to learn more about litterfall mercury monitoring.
The Litterfall Mercury Monitoring Network is a cooperative program between the USGS and the National Atmospheric Deposition Program (NADP). In addition to collecting litterfall samples, USGS provides NADP site operators with litterfall sampling kits. Samples are returned to the USGS and analyzed at the USGS Mercury Research lab. Results from the lab are reported back to NADP.
Litterfall Monitoring Benefits
- Low-cost method of measuring mercury dry deposition.
- Supplements NADP mercury wet deposition data
- Helps to constrain & verify inferential models of Hg dry deposition at NADP atmospheric mercury Network sites
Litterfall and Mercury Monitoring sites
- 29 mercury deposition network sites in 16 eastern US states with annual litterfall Mercury data from 2007 to 2015, plus Puerto Rico monthly monitoring
- 6 forest groups
How Do We Collect and Analyze Litterfall?
- 8 passive collectors per site, deployed randomly in forest study plot, August to end of litterfall drop
- Litterfall removed every 4 weeks, frozen until analyzed
- All litterfall dried and weighed
- Litterfall analyzed for mercury and methylmercury
- Annual litterfall Mercury dry deposition is mMercury concentration in litterfall samples (ng/g) X litterfall catch (g) = mercury mass / area (micrograms / sq. meter / year)
What have we found?
- Annual litterfall mercury dry deposition is generally equivalent to annual mercury.
- Generally low variability in litterfall mercury concentrations among the collectors in each forest study site.
Litterfall is leaves, needles, flowers, fruit, and debris found on the forest floor. Litterfall sampling can be an effective tool for monitoring elements like Mercury. Mercury in litterfall is primarily from the atmosphere and contributes to the higher amounts of mercury dry deposition that accumulates in forested areas compared to non-forested areas.
INKY scientists collect litterfall as part of the National Atmospheric Deposition Program (NADP) as well as provide litterfall sampling kits to NADP site operators who ship monthly samples back to USGS. The USGS Mercury Research lab analyzes the samples and reports the data to NADP.
Click on the Science tab above to learn more about litterfall mercury monitoring.
The Litterfall Mercury Monitoring Network is a cooperative program between the USGS and the National Atmospheric Deposition Program (NADP). In addition to collecting litterfall samples, USGS provides NADP site operators with litterfall sampling kits. Samples are returned to the USGS and analyzed at the USGS Mercury Research lab. Results from the lab are reported back to NADP.
Litterfall Monitoring Benefits
- Low-cost method of measuring mercury dry deposition.
- Supplements NADP mercury wet deposition data
- Helps to constrain & verify inferential models of Hg dry deposition at NADP atmospheric mercury Network sites
Litterfall and Mercury Monitoring sites
- 29 mercury deposition network sites in 16 eastern US states with annual litterfall Mercury data from 2007 to 2015, plus Puerto Rico monthly monitoring
- 6 forest groups
How Do We Collect and Analyze Litterfall?
- 8 passive collectors per site, deployed randomly in forest study plot, August to end of litterfall drop
- Litterfall removed every 4 weeks, frozen until analyzed
- All litterfall dried and weighed
- Litterfall analyzed for mercury and methylmercury
- Annual litterfall Mercury dry deposition is mMercury concentration in litterfall samples (ng/g) X litterfall catch (g) = mercury mass / area (micrograms / sq. meter / year)
What have we found?
- Annual litterfall mercury dry deposition is generally equivalent to annual mercury.
- Generally low variability in litterfall mercury concentrations among the collectors in each forest study site.