Different susceptibility to polycyclic aromatic hydrocarbons (PAH)-induced DNA damage in lung tissue in male and female non-smokers

The levels of benzo(a)pyrene diol-epoxide (BPDE)-DNA adducts and polycyclic aromatic hydrocarbons (PAH) were analysed in a limited number of samples of autoptic lung tissue obtained from non-professionally exposed male (n= 13) and female (n= 12) non-smokers in an attempt to evaluate the relationship between gender, lung PAH levels (n= 25) and susceptibility to BPDE-DNA adduct formation (n= 18). Lung concentrations of chrysene, benzo(g,h,i)perylene and benzo(a)pyrene were significantly higher in males than in females (P     

Degradation of eight highly condensed polycyclic aromatic hydrocarbons by Pleurotus sp. Florida in solid wheat straw substrate

The degradation of eight unlabeled highly condensed polycyclic aromatic hydrocarbons (PAH) and the mineralization of three ¹⁴C-labeled PAH by the white-rot fungus Pleurotus sp. Florida was investigated. Three concentrations containing 50, 250 or 1250 μg each unlabeled PAH/5 g straw were added to sterile sea sand. Selected treatments were added subsequently with ¹⁴C-labeled pyrene, benzo[a]anthracene or benzo[a]pyrene. The PAH-loaded sea sand was then mixed into straw substrate and incubated. The disappearance of the unlabeled four-to six-ring PAH: pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene and benzo[ghi]perylene, was determined by high-performance liquid chromatography. After 15 weeks of incubation, the recoveries were less than 25% for initial amounts of 50 μg (controls above 85%). The recoveries of unlabeled PAH increased in the inoculated samples with increasing concentrations applied. No correlation could be determined between the number of condensed rings of the PAH and the recoveries of added PAH. Pleurotus sp. Florida mineralized 53% [¹⁴C]pyrene, 25% [¹⁴C]benzo[a]anthracene and 39% [¹⁴C]benzo[a]pyrene to ¹⁴CO₂ in the presence of eight unlabeled PAH (50 μg applied) within 15 weeks. During the course of cultivation, Pleurotus sp. Florida degraded more than 40% of the wheat straw substrate. Variation of the initial concentration of PAH did not influence the extent of degradation of the organic matter. Received: 16 December 1996 / Received revision: 17 March 1997 / Accepted: 22 March 1997     

Biodegradation and sorption of polyaromatic hydrocarbons by Phanerochaete chrysosporium

The ability of the white-rot fungus Phanerochaete chrysosporium (INA-12) to degrade various polynuclear aromatic hydrocarbons (PAH) was investigated. Under static, non-nitrogen-limiting conditions, P. chrysosporium mineralized both phenanthrene and benzo[a]pyrene. Total mineralization, based on radioactive tracing, was limited to 1.8%–3% for phenanthrene and benzo[a]pyrene respectively. In both cases the pattern of mineralization did not correlate temporally with the production of lignin peroxidase activity. Sorption of radiolabelled material to the biomass was very significant with 22% and 40% of the total radioactivity being sorbed for benzo[a]pyrene and phenanthrene respectively. A number of models were examined to predict the sorption isotherms, the best performance being obtained with a three-parameter empirical model. It is apparent that lignin peroxidase is not necessarily involved in the biodegradation of all PAH and that a significant factor in PAH biodegradation and/or disappearance in cultures with the intact fungus may be attributed to sorption phenomena.     

Biodegradation of pyrene in sand,silt and clay fractions of sediment

Microbial degradation is the dominant pathway for natural attenuation of PAHs in environmental compartments such as sediments, which in turn depends on the bioavailability of PAHs. The bioavailability of PAHs has seldom been studied at the sediment particle size scale. We evaluated biodegradation of pyrene by Mycobacterium vanbaalenii PYR-1 as a function of sediment particle sizes, and investigated the relationship between the rate of degradation on sand, silt and clay particles with their individual desorption kinetics measured with the Tenax extraction method. Regression analysis showed that the total organic carbon (TOC), black carbon (BC), and specific surface area (SSA) of the specific particle size fractions, instead of the particle size scale itself, were closely related (P < 0.01) with the mineralization rate. While the fraction in the rapid desorption pool (F _rapid) ranged from 0.11 to 0.38 for the whole sediments and different size groups, the fractions mineralized after 336-h incubation (0.52 to 0.72) greatly surpassed the F _rapid values, suggesting utilization of pyrene in the slow desorption pool (F _slow). A biodegradation model was modified by imbedding a two-phase desorption relationship describing sequential Tenax extractions. Model analysis showed that pyrene sorbed on silt and clay aggregates was directly utilized by the degrading bacteria. The enhanced bioavailability may be attributed to the higher chemical concentration, higher TOC or larger SSA in the silt and clay fractions, which appeared to overcome the reduced bioavailability of pyrene due to sorption, making pyrene on the silt and clay particles readily available to degrading microbes. This conjecture merits further investigation.     

Degradation of polycyclic aromatic hydrocarbons in soil by a two-step sequential treatment

The objectives of this work were to isolate the microorganisms responsible for a previously observed degradation of polycyclic aromatic hydrocarbons (PAH) in soil and to test a method for cleaning a PAH-contaminated soil. An efficient PAH degrader was isolated from an agricultural soil and designated as Mycobacterium LP1. In liquid culture, it degraded phenanthrene (58%), pyrene (24%), anthracene (21%) and benzo(a)pyrene (10%) present in mixture (initial concentration 50 μg ml⁻¹ each) and phenanthrene (92%) and pyrene (94%) as sole carbon sources after 14 days of incubation at 30°C. In soil, Mycobacterium LP1 mineralised ¹⁴C-phenanthrene (45%) and ¹⁴C-pyrene (65%) after 10 days. The good ability of this Mycobacterium was combined with the benzo(a)pyrene oxidation effect obtained by 1% w/w rapeseed oil in a sequential treatment of a PAH-spiked soil (total PAH concentration 200 mg kg⁻¹). The first step was incubation with the bacterium for 12 days and the second step was the addition of the rapeseed oil after this time and a further incubation of 22 days. Phenanthrene (99%), pyrene (95%) and anthracene (99%) were mainly degraded in the first 12 days and a total of 85% of benzo(a)pyrene was transformed during the whole process. The feasibility of the method is discussed.     

Mycoremediation of PAH-contaminated soil

Out of a number of white-rot fungal cultures, strains ofIrpex lacteus andPleurotus ostreatus were selected for degradation of 7 three- and four-ring unsubstituted aromatic hydrocarbons (PAH) in two contaminated industrial soils. Respective data for removal of PAH in the two industrial soils byI. lacteus were: fluorene (41 and 67%), phenanthrene (20 and 56%), anthracene (29 and 49%), fluoranthene (29 and 57%), pyrene (24 and 42%), chrysene (16 and 32%) and benzo[a]anthracene (13 and 20%). In the same two industrial soilsP. ostreatus degraded the PAH with respective removal figures of fluorene (26 and 35%), phenanthrene (0 and 20%), anthracene (19 and 53%), fluoranthene (29 and 31%), pyrene (22 and 42%), chrysene (0 and 42%) and benzo[a]anthracene (0 and 13%). The degradation of PAH was determined against concentration of PAH in non-treated contaminated soils after 14 weeks of incubation. The fungal degradation of PAH in soil was studied simultaneously with ecotoxicity evaluation of fungal treated and non-treated contaminated soils. Compared to non-treated contaminated soil, fungus-treated soil samples indicated decrease in inhibition of bioluminescence in luminescent bacteria (Vibrio fischerii) and increase in germinated mustard (Brassica alba) seeds. An erratum to this article is available at .     

Successive transformation of benzo[a]pyrene by laccase of Trametes versicolor and pyrene-degrading Mycobacterium strains

We previously hypothesized that polycyclic aromatic hydrocarbon (PAH)-degrading bacteria that produce laccase may enhance the degree of benzo[a]pyrene mineralization. However, whether the metabolites of benzo[a]pyrene oxidized by laccase can be further transformed by PAH degraders remains unknown. In this study, pyrene-degrading mycobacteria with diverse degradation properties were isolated and employed for investigating the subsequent transformation on the metabolites of benzo[a]pyrene oxidized by fungal laccase of Trametes versicolor. The results confirm the successive transformation of benzo[a]pyrene metabolites, 6-benzo[a]pyrenyl acetate, and quinones by Mycobacterium strains, and report the discovery of the involvement of a O-methylation mediated pathway in the process. In detail, the vast majority of metabolite 6-benzo[a]pyrenyl acetate was transformed into benzo[a]pyrene quinones or methoxybenzo[a]pyrene, via two distinct steps that were controlled by the catechol-O-methyltransferase mediated O-methylation, while quinones were reduced to dihydroxybenzo[a]pyrene and further transformed into dimethoxy derivatives.     

Degradation of a mixture of high‐molecular‐weight polycyclic aromatic hydrocarbons by a Mycobacterium strain PYR‐1

Mycobacterium sp. PYR‐1, which was previously shown to mineralize several individual polycyclic aromatic hydrocarbons (PAHs), simultaneously degraded phenanthrene, anthracene, fluoranthene, pyrene and benzo[a]pyrene in a six‐component synthetic mixture. Chrysene was not degraded significantly. When provided with a complex carbon source, Mycobacterium sp. PYR‐1 degraded greater than 74% of the total PAH mixture during 6 d of incubation. Mycobacterium sp. PYR‐1 appeared to preferentially degrade phenanthrene. No significant difference in degradation rates was observed between fluoranthene and pyrene. Anthracene degradation was slightly delayed but, once initiated, proceeded at a constant rate. Benzo[a]pyrene was degraded slowly. Degradation of a crude mixture of benzene‐soluble PAHs from contaminated sediments resulted in a 47% reduction of the material in 6 d compared with that of autoclaved controls. Experiments using an environmental microcosm test system indicated that mineralization rates of individual ¹⁴C‐labeled compounds were significantly lower in the mixtures than in equivalent doses of these compounds alone. Mineralization of the complete mixture was estimated conservatively to be between 49.7 and 53.6% and was nearly 50% in 30 d of incubation when all compounds were radiolabeled. These results strengthen the argument for the potential application of Mycobacterium sp. PYR‐1 for bioremediation of PAH‐contaminated wastes.     

Predicting the Efficacy of Polycyclic Aromatic Hydrocarbon Bioremediation in Creosote-Contaminated Soil Using Bioavailability Assays

Nonexhaustive extraction (propanol, butanol, hydroxypropyl-β-cyclodextrin [HPCD]), persulfate oxidation and biodegradability assays were employed to determine the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in creosote-contaminated soil. After 16 weeks incubation, greater than 89% of three-ring compounds (acenaphthene, anthracene, fluorene, and phenanthrene) and 21% to 79% of four-ring compounds (benz[a]anthracene, chrysene, fluoranthene, and pyrene) were degraded by the indigenous microorganisms under biopile conditions. No significant decrease in five- (benzo[a]pyrene, benzo[b+k]fluoranthene) and six-ring compounds (benz[g,h,i]perylene, indeno[1,2,3-c,d]pyrene) was observed. Desorption of PAHs using propanol or butanol could not predict PAH biodegradability: low-molecular-weight PAH biodegradability was underestimated whereas high-molecular-weight PAH biodegradability was overestimated. Persulfate oxidation and HPCD extraction of creosote-contaminated soil was able to predict three- and four-ring PAH biodegradability; however, the biodegradability of five-ring PAHs was overestimated. These results demonstrate that persulfate oxidation and HPCD extraction are good predictors of PAH biodegradability for compounds with octanol-water partitioning coefficients of < 6.     

4S polycyclic aromatic hydrocarbon receptor (glycine N‐methyltransferase) and the aryl hydrocarbon receptor nuclear translocator (hypoxia inducible factor‐1β) interaction in Chinese hamster ovary and rat hepatoma cells: 4S PAH‐R/ARNT hetero‐oligomers?

Rat CYP1A1 promoter‐luciferase, transiently transfected wild‐type and 4S PAH receptor (glycine N‐methyl transferase, GNMT)‐transformed Chinese hamster ovary (CHO) cells were exposed to benzo[a]pyrene and assayed for luciferase activity as an indicator of CYP1A1 promoter activity. CHO cells transformed with the rat 4S PAH receptor/GNMT expression vector had twice the induction level of luciferase activity with respect to wild‐type CHO cells in concert with previously published reports that the 4S PAH receptor/GNMT mediates benzo[a]pyrene induction of CYP1A1 gene expression. Lysates of GNMT‐transformed CHO cells and wild‐type H4IIE rat hepatoma cells exposed to benzo[a]pyrene were immuno‐precipitated with anti‐GNMT antibodies, separated by SDS–polyacrylamide gel electrophoresis and transferred to PVDF membrane for Western blot analysis with anti‐aryl hydrocarbon receptor nuclear translocator (ARNT, HIF‐1β) antibodies. Results of this analysis indicated that the 4S PAH receptor/GNMT forms a hetero‐oligomer (dimer?) with ARNT/HIF‐1β which dissociates in the presence of B[a]P. These observations further indicate the role of GNMT (which has been shown to be multifunctional) and B[a]P in the induction of CYP1A1 and also a potential role of GNMT in the modulation of hypoxia inducible factor‐1 function with respect to the HIF‐1β subunit (ARNT). J. Cell. Biochem. 112: 2015–2018, 2011. © 2011 Wiley‐Liss, Inc.     

Seasonal Biotransformation of Naphthalene, Phenanthrene, and Benzo[a]pyrene in Surficial Estuarine Sediments

Transformation rates of naphthalene, phenanthrene, and benzo[a]pyrene in oxidized surficial sediments of a polluted urban estuary, Boston Harbor, Mass., were determined over a period of 15 months. Three sites characterized by muddy sediments were selected to represent a >300-fold range of ambient polycyclic aromatic hydrocarbon (PAH) concentration. Transformation rates were determined by a trace-level radiolabel PAH assay which accounted for PAH mineralization, the formation of polar metabolites, residue, and recovered parental PAHs in sediment slurries. Transformation rates of the model PAHs increased with increasing ambient PAH concentrations. However, turnover times for a given PAH were similar at all sites. The turnover times were as follows: naphthalene, 13.2 to 20.1 days; phenanthrene, 7.9 to 19.8 days, and benzo[a]pyrene, 53.7 to 82.3 days. At specific sites, rates were significantly affected by salinity, occasionally affected by temperature, but not affected by pH over the course of the study. Seasonal patterns of mineralization were observed for each of the PAHs at all sites. The timing of seasonal maxima of PAH mineralization varied from site to site. Seasonal potential heterotrophic activities as measured by acetate and glutamate mineralization rates did not always coincide with PAH mineralization maxima and minima, suggesting that the two processes are uncoupled in estuarine sediments.     

Effect of rapeseed oil on the degradation of polycyclic aromatic hydrocarbons in soil by Rhodococcus wratislaviensis

The effect of rapeseed oil (0, 0.1 and 1% w/w) on the degradation of polycyclic aromatic hydrocarbons (PAH) by Rhodococcus wratislaviensis was studied in soils artificially contaminated with phenanthrene, anthracene, pyrene and benzo(a)pyrene (50 mg kg⁻¹ each), during 49 days at 30 °C. Without or with 0.1% of rapeseed oil, R. wratislaviensis degraded >90% of phenanthrene and anthracene in 14 days and mineralised approx. 23% of ¹⁴C-phenanthrene. The native microflora degraded pyrene (90% degradation; 75% mineralisation) and benzo(a)pyrene (30% degradation, no mineralisation). With 1% rapeseed oil, R. wratislaviensis degraded only 66% of the phenanthrene and mineralised 12.4%, and had no effect on other PAH, while degradation by the native microflora was inhibited. On the other hand, the addition of 1% oil promoted degradation of benzo(a)pyrene (75%) and anthracene (90%) and anthraquinone was produced at high concentrations and accumulated. Two distinct processes gave degradation of PAH, one biological and one abiotic. Biological processes mainly degraded phenanthrene and pyrene, either by R. wratislaviensis or by the indigenous microflora. Benzo(a)pyrene was degraded mainly by an abiotic process in the presence of 1% rapeseed oil. Anthracene was degraded by a combination of both processes.PAH are often found in contaminated soils and there is the need of developing techniques that can be applied in the remediation of these sites, where PAH, specially those with high molecular weight, pose health and environmental risks. There is a continuous search for efficient microorganisms able to degrade these pollutants and for methods to enhance their degradation and bioavailability, e.g. by the use of vegetable oils. This paper presents a novel process for the degradation of PAH by a combined biological/abiotic system.     

Degradation of high molecular weight polycyclic aromatic hydrocarbons by Pseudomonas cepacia

Summary When inoculated at high cell densities, three strains of Pseudomonas cepacia degraded the polycyclic aromatic hydrocarbons (PAHs) benzo[a]pyrene, dibenz[a,h]anthracene and coronene as sole carbon and energy sources. After 63 days incubation, there was a 20 to 30% decrease in the concentration of benzo[a]pyrene and dibenz[a,h]anthracene and a 65 to 70% decrease in coronene concentration. The three strains were also able to degrade all the PAHs simultaneously in a PAH substrate mixture containing three-, four-, five- and seven-benzene ring compounds. Furthermore, improved degradation of the five- and seven-ring PAHs was observed when low molecular weight PAHs were present.     

Metabolite repression inhibits degradation of benzo[a]pyrene and dibenz[a,h]anthracene by Stenotrophomonas maltophilia VUN 10,003

Large inocula of Stenotrophomonas maltophilia VUN 10,003 were used to investigate bacterial degradation of benzo[a]pyrene and dibenz[a,h]anthracene. Although strain VUN 10,003 was capable of degrading 10–15 mg l⁻¹ of the five-ring compounds in the presence of pyrene after 63 days, further addition of pyrene after degradation of the five-ring polycyclic aromatic hydrocarbons (PAHs) ceased did not stimulate significant decreases in the concentration of benzo[a]pyrene or dibenz[a,h]anthracene. However, pyrene was degraded to undetectable levels 21 days after its addition. The amount of benzo[a]pyrene and dibenz[a,h]anthracene degraded by strain VUN 10,003 was not affected by the initial concentration of the compounds when tested at 25–100 mg l⁻¹, by the accumulation of by-products from pyrene catabolism or a loss of ability by the cells to catabolise benzo[a]pyrene or dibenz[a,h]anthracene. Metabolite or by-product repression was suspected to be responsible for the inhibition: By-products from the degradation of the five-ring compounds inhibited their further degradation. Journal of Industrial Microbiology & Biotechnology (2002) 28, 88–96 DOI: 10.1038/sj/jim/7000216 Received 30 January 2001/ Accepted in revised form 10 October 2001     

Assessment of occupational exposure to PAHs in an Estonian coke oven plant- correlation of total external exposure to internal dose measured as 1-hydroxypyrene concentration

The exposure of cokery workers to polynuclear aromatic hydrocarbons at an Estonian oil shale processing plant was assessed by using occupational hygiene and biomonitoring measurements which were carried out twice, in midwinter and in the autumn. To assess the external dose of polynuclear aromatic hydrocarbons, pyrene and benzo[a]pyrene concentrations were measured from the breathing zone of workers during a workshift. Skin contamination with pyrene and benzo[a]pyrene was assessed by skin wipe sampling before and after the workshift. As a biomarker of overall exposure to polynuclear aromatic hydrocarbons, and as an integral of all absorption routes of pyrene, 1-hydroxypyrene concentration was measured from post shift urine samples. Of the personal air samples, 18% exceeded the Finnish threshold limit value of benzo[a]pyrene (10 μg m^-3). Mean value (two separate measurements together) for benzo[a]pyrene was 5.7 μg m^-3 and for pyrene, 8.1 μg m^-3. Based on skin wipe sample analyses, the skin contamination was also obvious. The mean value of benzo[a]pyrene in the samples collected after the shift was 1.2 ng cm^-2. Benzo[a]pyrene was not found in control samples. The mean value of urinary 1-hydroxypyrene concentration was 6.0 μmol mol^-1 creatinine for the exposed workers and 0.5 μmol mol^-1 creatinine for the controls. This study undoubtedly shows the usefulness of 1-hydroxypyrene as an indicator of internal dose of polynuclear aromatic hydrocarbons. It can be concluded that the cokery workers at the Kohtla-Järve plant are exposed to high concentrations of polynuclear aromatic compounds, and the exposure level is considerably higher during the winter measurements.     

糙皮侧耳和鞘脂菌NS7对多环芳烃污染土壤的生物强化与协同作用

[背景] 真菌和细菌被认为在多环芳烃污染土壤生物修复过程中发挥协同作用,目前在真实土壤体系中开展真菌-细菌协同降解研究较少。[目的] 研究真菌和细菌对不同种类多环芳烃降解的差异及对蒽和苯并[a]蒽的生物强化与协同作用。[方法] 选用多环芳烃降解真菌和细菌各一株,在液体纯培养体系下分析它们对不同种类多环芳烃降解的差异,在土壤体系中采用放射性同位素示踪技术研究2种微生物对蒽和苯并[a]蒽的生物强化与协同作用。[结果] 供试细菌鞘脂菌NS7能够很好地降解低环种类多环芳烃,以蒽作为唯一碳源时可以将其完全降解,在复合污染条件下对菲、蒽、荧蒽、芘等降解效果突出（>90%）,对苯并[a]芘降解效果较差（9.76%）。相比而言,供试真菌糙皮侧耳菌对苯并[a]芘具有更好的降解效果（21.18%）,对低环多环芳烃降解效果明显不如降解菌NS7。在自然土壤中,蒽和苯并[a]蒽具有明显不同的矿化效率,分别为18.61%和4.28%,在蒽污染土壤中加入鞘脂菌NS7并未显著提高蒽的矿化率（P>0.05）,相比而言,苯并[a]蒽污染土壤中加入糙皮侧耳显著提高了污染物矿化效率（2.24倍）,表明真菌和细菌在土壤环境中的定殖存活能力可能影响了生物强化效果。采用灭菌土壤排除土著微生物的竞争排斥作用,研究了真菌菌丝对生物强化降解的影响,发现在蒽污染土壤中,真菌菌丝的迁移作用显著提高了细菌鞘脂菌NS7对污染物的矿化率,从1.75%提高到5.91%;而在苯并[a]蒽灭菌污染土壤中,接种糙皮侧耳却没有发现苯并[a]蒽矿化率提高的现象,表明自然土壤中真菌强化降解苯并[a]蒽的作用可能是源于真菌菌丝促进污染物和土著降解菌的接触,而非直接来自真菌本身。[结论] 细菌能够很好地降解低环种类多环芳烃,而真菌对高环种类多环芳烃降解效果较好。真菌可能通过菌丝促进土著微生物在土壤中的迁移,增大多环芳烃和土著降解菌的接触,从而促进了多环芳烃降解。研究加深了对多环芳烃污染土壤生物强化修复的认识,对发展基于真菌-细菌协同作用的生物强化与调控技术提供理论指导。     

Two-step error-prone bypass of the (+)- and (−)-trans-anti-BPDE-N-dG adducts by human DNA polymerases η and κ

Benzo[a]pyrene is a polycyclic aromatic hydrocarbon (PAH) associated with potent carcinogenic activity. Mutagenesis induced by benzo[a]pyrene DNA adducts is believed to involve error-prone translesion synthesis opposite the lesion. However, the DNA polymerase involved in this process has not been clearly defined in eukaryotes. Here, we provide biochemical evidence suggesting a role for DNA polymerase η (Polη) in mutagenesis induced by benzo[a]pyrene DNA adducts in cells. Purified human Polη predominantly inserted an A opposite a template (+)- and (−)-trans-anti-BPDE-N²-dG, two important DNA adducts of benzo[a]pyrene. Both lesions also dramatically elevated G and T mis-insertion error rates of human Polη. Error-prone nucleotide insertion by human Polη was more efficient opposite the (+)-trans-anti-BPDE-N²-dG adduct than opposite the (−)-trans-anti-BPDE-N²-dG. However, translesion synthesis by human Polη largely stopped opposite the lesion and at one nucleotide downstream of the lesion (+1 extension). The limited extension synthesis of human Polη from opposite the lesion was strongly affected by the stereochemistry of the trans-anti-BPDE-N²-dG adducts, the nucleotide opposite the lesion, and the sequence context 5′ to the lesion. By combining the nucleotide insertion activity of human Polη and the extension synthesis activity of human Polκ, effective error-prone lesion bypass was achieved in vitro in response to the (+)- and (−)-trans-anti-BPDE-N²-dG DNA adducts.     

Phytoremediation of Soils Contaminated with Wood Preservatives: Greenhouse and Field Evaluations

Phytoremediation was evaluated as a potential treatment for the creosote-contaminated surface soil at the McCormick and Baxter (M&B) Superfund Site in Portland, Oregon. Soil at the M&B site is contaminated with pentachlorophenol (PCP) and polyaromatic hydrocarbons (PAHs). Eight individual PAH compounds (containing four to six aromatic rings) were included in the investigation. Greenhouse and field studies were carried out using perennial ryegrass (Lolium perenne). The following three treatments were compared in both studies: T1 = planted-amended soil; T2 = unplanted-amended soil; and T3 = unplanted-unamended soil. The amendments were mineral nutrients and dolomite, which was used to raise the acidic pH of the soil. Contaminant concentrations in the soil were measured initially and at regular intervals for several months. In the greenhouse study, the concentrations of certain contaminants decreased as a function of time. Thus, PCP, fluoranthene, pyrene, chrysene, and benzo(k)fluoranthene appeared to undergo biodegradation in all of the treatments. On the other hand, certain larger molecular weight PAHs were relatively recalcitrant. These “recalcitrant PAHs” included benzo(b)fluoranthene, benzo(a)pyrene, benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene. Statistical methods were used to compare the concentrations of the more easily biodegraded contaminants in treatments T1, T2, and T3. The statistical analysis was facilitated by normalizing the contaminant concentrations relative to the sum of the recalcitrant PAHs in the same sample. Thus, ratios were created that could be compared directly to benchmark values indicative of the contaminant at the beginning of the study. In the greenhouse study, statistically significant differences between T1 and T2, across all treatment times, were obtained for fluoranthene, pyrene, and chrysene (p ≤0.05), suggesting enhanced rhizosphere biodegradation for these compounds. Significant differences between T2 and T3 were obtained for pyrene (p ≤0.03), indicating that nutrients stimulated the biodegradation of this contaminant. Although the greenhouse study was carried out with a well-mixed soil sample from the M&B site, an extremely uneven distribution of contaminants was encountered in the field study. The resulting scatter in the field data made comparisons difficult, and treatment-specific effects observed in the greenhouse study were not statistically significant in the field study. However, analysis of the normalized data from the field revealed the same time-dependent decreases in contaminant concentration as observed in the greenhouse study.     

Screening filamentous fungi isolated from estuarine sediments for the ability to oxidize polycyclic aromatic hydrocarbons

Nineteen filamentous fungi, isolated from estuarine sediments in Brazil, were screened for degradation of polycyclic aromatic hydrocarbons (PAH). The fungal isolates were incubated with pyrene. The cultures were extracted and metabolites in the extracts were detected by high performance liquid chromatography (HPLC) and u.v. spectral analyses. Six fungi were selected for further studies using [4,5,9,10-¹⁴C]pyrene. Cyclothyrium sp., Penicillium simplicissimum, Psilocybe sp., and a sterile mycelium demonstrated the ability to transform pyrene. Cyclothyrium sp. was the most efficient fungus, transforming 48% of pyrene to pyrene trans-4,5-dihydrodiol, pyrene-1,6-quinone, pyrene-1,8-quinone and 1-hydroxypyrene. This fungus was also evaluated with a synthetic mixture of PAH. After 192 h of incubation, Cyclothyrium sp. was able to degrade simultaneously 70, 74, 59 and 38% of phenanthrene, pyrene, anthracene and benzo[a]pyrene, respectively.     

Potential Health Risk of Reused Creosote-Treated Old Railway Ties at Recreational Sites in Korea

Old creosote-treated railway ties reused at recreational sites in Korea are potential hazards, due to the presence of harmful substances in creosote, such as polycyclic aromatic hydrocarbons (PAHs). In such sites, PAHs in ties can be leached or emitted, and human exposure might then occur. In this study, the concentrations of 16 PAHs in soil, air, and tie surfaces in old creosote-treated railway ties reused in recreational sites were investigated, and the potential health risk of the ties was evaluated through two exposure scenarios: a recreational scenario (ingestion of and dermal contact with soil and inhalation of soil particles) and a playground scenario (ingestion after contact and dermal contact with ties). For the recreational scenario, the health risks of PAHs were safe; however, for the playground scenario, the carcinogenic risk of ingestion after contact, and dermal contact with benz(a)anthracene and benzo(a)pyrene on the tie surfaces, exceeded the acceptable risk level (10^–6). For the carcinogenic risks of ingestion after contact with ties, the probabilities of cancer development were 8 and 5 in one million people for benz(a)anthracene and benzo(a)pyrene, respectively. The carcinogenic risks for dermal contact with ties were 2.4 × 10^–6 and 1.4 × 10^–6 for benz(a)anthracene and benzo(a)pyrene, respectively.