title: Trace Metals and Metalloids in Forest Soils and Exotic Earthworms in Northern New England, USA.
abstract: Trace metals and metalloids (TMM) in forest soils and invasive earthworms were studied at 9 uncontaminated sites in northern New England, USA. Essential (Cu, Mo, Ni, Zn, Se) and toxic (As, Cd, Pb, Hg and U) TMM concentrations (mg kg-1) and pools (mg m-2) were quantified for organic horizons (forest floor), mineral soils and earthworm tissues. Essential TMM tissue concentrations were greatest for mineral soil-feeding earthwormOctolasion cyaneum. Toxic TMM tissue concentrations were highest for organic horizon-feeding earthwormsDendobaena octaedra,Aporrectodea roseaandAmynthas agrestis. Most earthworm species had attained tissue concentrations of Pb, Hg and Se potentially hazardous to predators. Bioaccumulation factors were Cd > Se > Hg > Zn > Pb > U > 1.0 > Cu > As > Mo > Ni. Only Cd, Se Hg and Zn were considered strongly bioaccumulated by earthworms because their average bioaccumulation factors were significantly greater than 1.0. Differences in bioaccumulation did not appear to be caused by soil concentrations as earthworm TMM tissue concentrations were poorly correlated with TMM soil concentrations. Instead, TMM bioaccumulation appears to be species and site dependent. The invasiveAmynthas agrestishad the greatest tissue TMM pools, due to its large body mass and high abundance at our stands. We observed that TMM tissue pools in earthworms were comparable or exceeded organic horizon TMM pools; earthworm tissue pools of Cd were up 12 times greater than in the organic horizon. Thus, exotic earthworms may represent an unaccounted portion and flux of TMM in forests of the northeastern US. Our results highlight the importance of earthworms in TMM cycling in northern forests and warrant more research into their impact across the region.
authors.affiliation: Environmental Studies Program, Dartmouth College, Hanover, NH 03755 USA ; Department of Earth Science, Dartmouth College, Hanover, NH 03755 USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Richardson
authors.affiliation: Department of Plant & Soil Science, University of Vermont, Burlington, VT 05405 USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Görres
authors.affiliation: Department of Earth Science, Dartmouth College, Hanover, NH 03755 USA.
authors.forename: B P
authors.initials: BP
authors.lastname: Jackson
authors.affiliation: Environmental Studies Program, Dartmouth College, Hanover, NH 03755 USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Friedland
keywords: bioaccumulation; heavy metals; invasive earthworms; lead; mercury; selenium; trace elements; unpolluted soil