title: Ecotoxicology of mercury in tropical forest soils: Impact on earthworms.
abstract: Mercury (Hg) is one of the most toxic nonessential trace metals in the environment, with high persistence and bioaccumulation potential, and hence of serious concern to environmental quality and public health. Emitted to the atmosphere, this element can travel long distances, far from emission sources. Hg speciation can lead to Hg contamination of different ecosystem components, as well as biomagnification in trophic food webs. To evaluate the effects of atmospheric Hg deposition in tropical forests, we investigated Hg concentrations in earthworm tissues and soils of two Forest Conservation Units in State of Rio de Janeiro, Brazil. Next, we performed a laboratory study of the biological responses (cast analysis and behavioral, acute, chronic and bioaccumulation ecotoxicological tests) of two earthworms species (Pontoscolex corethrurus and Eisenia andrei) to Hg contamination in tropical artificial soil (TAS) and two natural forest soils (NS) spiked with increasing concentration of HgCl2. Field results showed Hg concentrations up to 13 times higher in earthworm tissues than in forest soils, while in the laboratory Hg accumulation after 91-days of exposure was 25 times greater in spiked-soils with 128mgHgkg-1(dry wt) than in control (unspiked) soils. In all the toxicity tests P. corethrurus showed a higher adaptability or resistance to mercury than E. andrei. The role of earthworms as environmental bioremediators was confirmed in this study, showing their ability to greatly bioaccumulate trace metals while reducing Hg availability in feces.
authors.affiliation: Department of Environmental Geochemistry, Fluminense Federal University, Outeiro São João Baptista, s/n., Centro, 24020-007 Niterói, RJ, Brazil. Electronic address: andressabuch@hotmail.com.
authors.forename: Andressa Cristhy
authors.initials: AC
authors.lastname: Buch
authors.affiliation: Embrapa Forestry, Estrada da Ribeira km. 111, C.P. 319, 83411-000 Colombo, PR, Brazil.
authors.forename: George Gardner
authors.initials: GG
authors.lastname: Brown
authors.affiliation: Embrapa Agrobiology, BR 465 km. 7, 23890-000 Seropédica, RJ, Brazil.
authors.forename: Maria Elizabeth Fernandes
authors.initials: MEF
authors.lastname: Correia
authors.affiliation: Department of Environmental Geochemistry, Fluminense Federal University, Outeiro São João Baptista, s/n., Centro, 24020-007 Niterói, RJ, Brazil.
authors.forename: Lúcio Fábio
authors.initials: LF
authors.lastname: Lourençato
authors.affiliation: Department of Environmental Geochemistry, Fluminense Federal University, Outeiro São João Baptista, s/n., Centro, 24020-007 Niterói, RJ, Brazil.
authors.forename: Emmanoel Vieira
authors.initials: EV
authors.lastname: Silva-Filho
mesh_terms: D000818:Animals; D001938:Brazil; D054750:Ecotoxicology; D020387:Food Chain; D065928:Forests; D008628:Mercury / Q000633:toxicity*; D009835:Oligochaeta / Q000187:drug effects*; D012987:Soil; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D008628:Mercury
keywords: Cast production; Eisenia andrei; Environmental quality; Pontoscolex corethrurus; Terrestrial ecotoxicology; Trace metal