Long-Term Fate of Polychlorinated Biphenyls and Polycyclic Aromatic Hydrocarbons in an Agricultural Soil

Abstract

Laboratory studies are useful for understanding the behavior of persistent organic pollutants (POPs) in soil, although such investigations do not always relate directly to field conditions. Outdoor lysimeter studies may be used to overcome this problem. This work aimed to investigate the behavior of two polycyclic aromatic hydrocarbons (PAHs) (fluoranthene and benzo[a]pyrene) and two polychlorinated biphenyls (PCBs; congeners 28 and 52) in soil, using lysimeters established in 1990 atthe Agrosphere Institute (Forschungszentrum Julich GmbH, Germany). The two PAHs were in one lysimeter, and the PCBs were in a second lysimeter. Afurther aim of the study was to determine soil half-lives for each of the contaminants. The overall decline in PAH concentrations was considerably greater than forthe PCBs over the 152 month study. The PCBs exhibited greater chemical extractability than the PAHs and were demonstrated to have migrated through the soil column to a greater extent than the PAHs. Loss of PCBs from surface soil was not considered to have been congener specific for the two PCB congeners in this study. The two PAHs varied in their extents of total loss and movement through the soil column. Soil half-lives were determined as 10.9 y for [12C]PCB 28, 11.2 yr for [12C]PCB 52, 2.7 yr for benzoqpyrene, and 32 d (phase 1) to 38 yr (phase 2) for fluoranthene. These are shown to disagree with some previous estimates of POP half-lives in soil, suggesting that previous studies underestimated persistence by 10-fold or more.

Characteristic accumulation and soil penetration of polychlorinated biphenyls and polybrominated diphenyl ethers in wastewater irrigated farmlands

“…A similar trend was found in contaminated paddy soils in southern China (Bi et al, 2002). Several studies found that leaching of PCBs through the soil column should not be significant due to their relatively low water solubilities and large Kow values (Cousins et al, 1999;Doick et al, 2005). However, other studies on soil surface profiles in forest and montane areas suggest that leaching of PCBs can occur, mostly in association with DOM (Krauss et al, 2000;Moeckel et al, 2008).…”

Spatial distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in soils from typical oil-sewage irrigation area, Northeast China

“…Doick et al (2005) reported that the half-life for BaP was 2.7 yr in soil, which might be changed by soil characteristics (the amount and quality of soil organic matter) and the environmental situation (content of oxygen and nutrients). In the SIA, the mean concentration of BaP was 0.34 mg kg −1 in surface soil, 0.11 mg kg −1 in subsurface soil, and was much higher than the natural concentrations (0.8-4.3 μg kg −1 ; Knoche et al 1995).…”

Aerobic biodegradation and inhibition kinetics of poly‐aromatic hydrocarbons (PAHs) in a petrochemical industry wastewater in the presence of biosurfactants

“…However, the efficiency of high molecular weight PAHs biodegradation is limited because these compounds have a very low aqueous solubility and vapour pressure. 3 Cutright, 4 Cajthaml et al 5 and Doick et al 6 found that the PAHs were degraded according to first-order reaction kinetics in wastewaters and soils without biosurfactant addition. 4 -6 The studies performed by Abalos et al, 7 Yin et al, 8 Zhou and Zhu 9 and Yu et al 10 showed that biosurfactants play an important role in the degradation of PAHs from petrochemical industry wastewaters Although studies have been conducted to enhance the biodegradation of less hydrophobic PAHs using surfactants to increase their solubility by decreasing the interfacial surface tension between PAHs and the water interphase, 7,9,11,12 limited data were found for the biodegradation kinetic of hydrophobic PAHs.…”