The release of the hydrophobic organic compounds pyrene, dibenzofuran and phenanthrene from bioturbated freshwater sediments was studied in laboratory microcosms. Initial Tubificid oligochaete densities of 0, 6700 and 2.67 x 10' individuala - m` were employed. Under oxygen saturateti conditions, the differenee between the contaminant fluxes from the high-density bioturbated microcosms and controls remained essentially constane at 37 and 70 ng • cm` - d` for pyrene and phenanthrene, respectively, corresponding io effective mass transfer coefficients of 0.16 and 0.37 cm/y. Under hypoxic conditions, worm defecation on the sediment surface increased and led to significantly increased fluxes to a maximum of 380, 490 and 940 ng - cm-2 • d`, for pyrene, phenanthrene and dibenzofuran, respectively. Average bioturbation fluxes in the high-density microcosms of 246, 258 and 310 ng - cm` - d-' for the respective compounds corresponded to effective mass transfer coefficients of 1.7, 3.2, and 7.5 cm/yr. Initial release ratea from medium-density microcosms (25% of high density) were typically hall the release rate of the high-density microcosms, indicating greater organism aetivity per individua[ at the lower density. The increased flux with the more soluble compounds likely reflects more rapiti release at the sediment surface and the increased importance of porewater pumping over sediment partiele reworking for migration of these compounds.

Contaminant fluxes from sediment due to Tubifex bioturbation / Reible, D. D.; Popov, V.; Valsaraj, K. T.; Thibodeaux, L. J.; Lin, F.; Dikshit, M.; Todaro, Mary Antonio Donatello; Fleeger, J. W.. - In: WATER RESEARCH. - ISSN 0043-1354. - STAMPA. - 30:(1996), pp. 704-714.

Contaminant fluxes from sediment due to Tubifex bioturbation

TODARO, Mary Antonio Donatello;
1996

Abstract

The release of the hydrophobic organic compounds pyrene, dibenzofuran and phenanthrene from bioturbated freshwater sediments was studied in laboratory microcosms. Initial Tubificid oligochaete densities of 0, 6700 and 2.67 x 10' individuala - m` were employed. Under oxygen saturateti conditions, the differenee between the contaminant fluxes from the high-density bioturbated microcosms and controls remained essentially constane at 37 and 70 ng • cm` - d` for pyrene and phenanthrene, respectively, corresponding io effective mass transfer coefficients of 0.16 and 0.37 cm/y. Under hypoxic conditions, worm defecation on the sediment surface increased and led to significantly increased fluxes to a maximum of 380, 490 and 940 ng - cm-2 • d`, for pyrene, phenanthrene and dibenzofuran, respectively. Average bioturbation fluxes in the high-density microcosms of 246, 258 and 310 ng - cm` - d-' for the respective compounds corresponded to effective mass transfer coefficients of 1.7, 3.2, and 7.5 cm/yr. Initial release ratea from medium-density microcosms (25% of high density) were typically hall the release rate of the high-density microcosms, indicating greater organism aetivity per individua[ at the lower density. The increased flux with the more soluble compounds likely reflects more rapiti release at the sediment surface and the increased importance of porewater pumping over sediment partiele reworking for migration of these compounds.
1996
30
704
714
Contaminant fluxes from sediment due to Tubifex bioturbation / Reible, D. D.; Popov, V.; Valsaraj, K. T.; Thibodeaux, L. J.; Lin, F.; Dikshit, M.; Todaro, Mary Antonio Donatello; Fleeger, J. W.. - In: WATER RESEARCH. - ISSN 0043-1354. - STAMPA. - 30:(1996), pp. 704-714.
Reible, D. D.; Popov, V.; Valsaraj, K. T.; Thibodeaux, L. J.; Lin, F.; Dikshit, M.; Todaro, Mary Antonio Donatello; Fleeger, J. W.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/459329
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