This paper evaluated the effects of a pig manure compost (PMC) and a nonionic surfactant Tween 80 on the fate of C-14-Pyrene (Pyr) in a soil-plant system (Agropyron elongatum). Soils spiked with C-14-4, 5, 9, 10-Pyr were amended with 7.5% (w/w) PMC together with or without 100 mg kg(-1) of Tween 80. Unplanted soil without amendments was set as the control. Gas phases of the systems were monitored for (CO2)-C-14 over a 60 days period. The impact of PMC and Tween 80 on the apparent loss of the PAH and the distribution of C-14-activity in the systems was studied. C-14-activity associated with different soil fractions was further examined by using methyl-isobutyl-ketone (MIBK) fractionation method. The results showed that the addition of PMC could increase the dissipation of Pyr in vegetated soil from 12.1% to 58.7%, while the co-addition of Tween 80 and PMC could further enhance the dissipation to 90.3%. Pyr dissipation in soil was correlated with the mineralization of C-14-Pyr, indicating that Pyr dissipation was mainly due to mineralization. A higher formation of water-extractable metabolites was observed in soil amended with PMC and Tween 80, and this was correlated with a higher biomass accumulation of C-14-activity and higher bound residue formation in the soil. Overall, this study suggested that the co-application of PMC and Tween 80 could improve phytoremediation of Pyr-contarninated soil. (c) 2008 Published by Elsevier Ltd.