Fate of 14C-Pyrene in soil-plant system amended with pig manure compost and Tween 80: a growth chamber study

This paper evaluated the effects of a pig manure compost (PMC) and a nonionic surfactant Tween 80 on the fate of (14)C-Pyrene (Pyr) in a soil-plant system (Agropyron elongatum). Soils spiked with (14)C-4, 5, 9, 10-Pyr were amended with 7.5% (w/w) PMC together with or without 100mgkg(-1) of Tween 80. Unplanted soil without amendments was set as the control. Gas phases of the systems were monitored for (14)CO(2) over a 60 days period. The impact of PMC and Tween 80 on the apparent loss of the PAH and the distribution of (14)C-activity in the systems was studied. (14)C-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 (14)C-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 (14)C-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-contaminated soil.