TY - JOUR
T1 - Desorption controlled mobility and intrinsic biodegradation of anthracene in unsaturated soil
AU - Weigand, H.
AU - Totsche, K. U.
AU - Kögel-Knabner, I.
AU - Annweiler, E.
AU - Richnow, H. H.
AU - Michaelis, W.
PY - 1999
Y1 - 1999
N2 - Desorption, sorption and biodegradation control the fate of polycyclic aromatic hydrocarbons (PAH) in contaminated soils. The interaction of these processes was studied in a two-layer column experiment with uncontaminated and spiked A-horizon material (13C anthracene) at saturated water flow conditions. During constant irrigation (part I of the experiment) the development of a stationary effluent composition was observed. The onset of anthracene breakthrough was delayed by 350 pore volumes (pvs) indicating high affinity sorption towards soil organic matter. The coincidence of anthracene breakthrough with increasing dissolved organic carbon (DOC) concentrations pointed to a carrier-mediated transport of the contaminant. Flow interruptions of varied duration (part II of the experiment) yielded a pronounced response of solution phase parameters. Effluent DOC increased linearly with time of flow interruption, indicating a zero-order rate-limited release. In contrast anthracene concentrations showed a sharp drop after the stopped-flow events. Thus, the effluent anthracene concentration observed in part I may have been controlled by rate-limited sorption in the uncontaminated layer. Biodegradation of anthracene was evident from 13C-labelled and the complete decline of effluent anthracene after 1400 pvs. Although PAH seepage in soils is enhanced by rate-limited sorption it may be effectively counteracted by microbial activity.
AB - Desorption, sorption and biodegradation control the fate of polycyclic aromatic hydrocarbons (PAH) in contaminated soils. The interaction of these processes was studied in a two-layer column experiment with uncontaminated and spiked A-horizon material (13C anthracene) at saturated water flow conditions. During constant irrigation (part I of the experiment) the development of a stationary effluent composition was observed. The onset of anthracene breakthrough was delayed by 350 pore volumes (pvs) indicating high affinity sorption towards soil organic matter. The coincidence of anthracene breakthrough with increasing dissolved organic carbon (DOC) concentrations pointed to a carrier-mediated transport of the contaminant. Flow interruptions of varied duration (part II of the experiment) yielded a pronounced response of solution phase parameters. Effluent DOC increased linearly with time of flow interruption, indicating a zero-order rate-limited release. In contrast anthracene concentrations showed a sharp drop after the stopped-flow events. Thus, the effluent anthracene concentration observed in part I may have been controlled by rate-limited sorption in the uncontaminated layer. Biodegradation of anthracene was evident from 13C-labelled and the complete decline of effluent anthracene after 1400 pvs. Although PAH seepage in soils is enhanced by rate-limited sorption it may be effectively counteracted by microbial activity.
UR - http://www.scopus.com/inward/record.url?scp=0033402728&partnerID=8YFLogxK
U2 - 10.1016/S1464-1909(99)00043-X
DO - 10.1016/S1464-1909(99)00043-X
M3 - Article
AN - SCOPUS:0033402728
SN - 1464-1909
VL - 24
SP - 549
EP - 555
JO - Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere
JF - Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere
IS - 6
ER -