Cloud water and throughfall deposition of mercury and trace elements in a high elevation spruce–fir forest at Mt. Mansfield, Vermont

Abstract

As part of the Lake Champlain Basin watershed study of mercury (Hg) and pollutant deposition, cloud water and cloud throughfall collections were conducted at the south summit (1204 m) of Mt. Mansfield, Vermont between August 1 and October 31, 1998, for multi-element chemical analysis. A passive Teflon string collector was deployed during non-precipitating events to sample cloud/fog water at timberline, while three sets of paired funnels collected cloud throughfall under the red spruce-balsam fir canopy. Samples were analyzed for concentrations of Hg, major ions, and 10 trace elements. Ultra-clean sampling and analysis techniques were utilized throughout the study. Six events were sampled for cloud water alone and four events were sampled for both cloud water and cloud throughfall. Cloud throughfall chemistry showed substantial modification from incident cloud water. Much higher concentrations of Hg (2.3 x), base cations (Ca2+, K-, Mg2+; 3-18 x) and certain trace elements (Ni, Cu, Mn, Rb, Sr; 2-34 x) were observed in throughfall than in cloud water. These results confirm that cloud water can leach a wide variety of elements from tree foliage and wash off dry deposited elements. Cloud water deposited an average of 0.42 +/- 0.12 mm of water per hour. Estimated cloud water deposition of Hg was 7.4 microg m(-2) for the period August 1-October 31, approximately twice that deposited by rain during this period at a nearby low elevation Hg monitoring site. Our results indicate that cloud water and Hg deposition at Mt. Mansfield are likely to have considerable ecological effects.

Modeling and Mapping of Atmospheric Mercury Deposition in Adirondack Park, New York

“…Secondly, Hg deposition is likely to be higher in greater elevation areas. There are a few field studies [65], [66] as well as a modeling study [23]) that consider the effect of elevation on Hg deposition. Hg deposition velocities increased with increasing elevation due to increases in wind speed, although the effect may be offset by the relatively lower temperature at these sites.…”

Major and trace elements in soils in the Central Pyrenees: high altitude soils as a cumulative record of background atmospheric contamination over SW Europe

“…limit must be taken into consideration. Thus, interception of dry deposition by the canopy and the subsequent enriched throughfall deposition could also contribute to enhanced deposition of atmospherically transported elements at lower altitudes (Lawson et al 2003;Avila and Rodrigo 2004). Moreover, soils under conifers may show improved retention of deposited trace elements because of greater amounts of organic acids (Lovett and Kinsman 1990).…”

Deposition of mercury in forests across a montane elevation gradient: Elevational and seasonal patterns in methylmercury inputs and production

“…Based upon soil characteristics, tree species, precipitation patterns, and expected Hg inputs, ecosystems at higher elevations are thought to receive higher Hg deposition and support greater methylation [ Lawson et al, ; Yu et al, ]. Findings of increased Hg concentrations in invertebrates, salamanders, and birds [ Blais et al, ; Townsend et al, ], along with higher concentration of other contaminants [ Reiners et al, ; Lovett and Kinsman , ; Miller et al, ; Lawson et al, ], with increases in elevation support this hypothesis. Moreover, several studies have also reported higher concentrations of soil THg in coniferous stands compared to deciduous forests [ Kolka et al, ; Graydon et al, ; Fisher and Wolfe , ].…”

“…Storage capacity of Hg within soils is enhanced by organic matter (OM) content, but the exact role of elevation remains poorly characterized [Yu et al, 2011;Townsend et al, 2014]. Based upon soil characteristics, tree species, precipitation patterns, and expected Hg inputs, ecosystems at higher elevations are thought to receive higher Hg deposition and support greater methylation [Lawson et al, 2003;Yu et al, 2014]. Findings of increased Hg concentrations in invertebrates, salamanders, and birds [Blais et al, 2006;Townsend et al, 2014], along with higher concentration of other contaminants [Reiners et al, 1975;Lovett and Kinsman, 1990;Miller et al, 1993;Lawson et al, 2003], with increases in elevation support this hypothesis.…”