title: Aerobic Bioremediation of PAH Contaminated Soil Results in Increased Genotoxicity and Developmental Toxicity.
abstract: The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (prebioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (postbioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, postbioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental toxicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, postbioremediation (p < 0.05). In addition, a statistically significant increase in developmental toxicity was measured in one polar soil extract fraction, postbioremediation (p < 0.05). A series of morphological abnormalities, including peculiar caudal fin malformations and hyperpigmentation in the tail, were measured in several soil extract fractions in embryonic zebrafish, both pre- and postbioremediation. The increased toxicity measured postbioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase postbioremediation. However, the increased toxicity measured postbioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1MPHE, 2MPHE, PRY, BaA, and FLA) that were most degraded.
authors.affiliation: Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Leah
authors.initials: L
authors.lastname: Chibwe
authors.affiliation: Department of Environmental & Molecular Toxicology, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Mitra C
authors.initials: MC
authors.lastname: Geier
authors.affiliation: Department of Environmental Sciences & Engineering, University of North Carolina , Chapel Hill, North Carolina 27599, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Nakamura
authors.affiliation: Department of Environmental & Molecular Toxicology, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Tanguay
authors.affiliation: Department of Environmental Sciences & Engineering, University of North Carolina , Chapel Hill, North Carolina 27599, United States.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Aitken
authors.affiliation: Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States.|Department of Environmental & Molecular Toxicology, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Staci L Massey
authors.initials: SL
authors.lastname: Simonich
mesh_terms: D000332:Aerobiosis; D000818:Animals; D001673:Biodegradation, Environmental; D001681:Biological Assay; D002645:Chickens; D054750:Ecotoxicology / Q000379:methods; D004625:Embryo, Nonmammalian / Q000187:drug effects; D052918:Environmental Restoration and Remediation / Q000379:methods*; D009152:Mutagenicity Tests / Q000379:methods; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods*; D015027:Zebrafish / Q000196:embryology
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants