Sorption of native polyaromatic hydrocarbons (PAH) to black carbon and amended activated carbon in soil

Organic pollutants (e.g. polyaromatic hydrocarbons (PAH)) strongly sorb to carbonaceous sorbents such as black carbon and activated carbon (BC and AC, respectively). For a creosote-contaminated soil (Sigma15PAH 5500 mg kg(dry weight(dw))(-1)) and an urban soil with moderate PAH content (Sigma15PAH 38 mg kg(dw)(-1)), total organic carbon-water distribution coefficients (K(TOC)) were up to a factor of 100 above values for amorphous (humic) organic carbon obtained by a frequently used Linear-Free-Energy Relationship. This increase could be explained by inclusion of BC (urban soil) or oil (creosote-contaminated soil) into the sorption model. AC is a manufactured sorbent for organic pollutants with similar strong sorption properties as the combustion by-product BC. AC has the potential to be used for in situ remediation of contaminated soils and sediments. The addition of small amounts of powdered AC (2%) to the moderately contaminated urban soil reduced the freely dissolved aqueous concentration of native PAH in soil/water suspensions up to 99%. For granulated AC amended to the urban soil, the reduction in freely dissolved concentrations was not as strong (median 64%), especially for the heavier PAH. This is probably due to blockage of the pore system of granulated AC resulting in AC deactivation by soil components. For powdered and granulated AC amended to the heavily contaminated creosote soil, median reductions were 63% and 4%, respectively, probably due to saturation of AC sorption sites by the high PAH concentrations and/or blockage of sorption sites and pores by oil.     

Effect of catchment land use and soil type on the concentration,quality, and bacterial degradation of riverine dissolved organic matter

We studied the effects of catchment characteristics (soil type and land use) on the concentration and quality of dissolved organic matter (DOM) in river water and on the bacterial degradation of terrestrial DOM. The share of organic soil was the strongest predictor of high concentrations of dissolved organic carbon, nitrogen, and phosphorus (DOC, DON, and DOP, respectively), and was linked to DOM quality. Soil type was more important than land use in determining the concentration and quality of riverine DOM. On average, 5–9 % of the DOC and 45 % of the DON were degraded by the bacterial communities within 2–3 months. Simultaneously, the proportion of humic-like compounds in the DOM pool increased. Bioavailable DON accounted for approximately one-third of the total bioavailable dissolved nitrogen, and thus, terrestrial DON can markedly contribute to the coastal plankton dynamics and support the heterotrophic food web.     

Effect of introduced phthalate-degrading bacteria on the diversity of indigenous bacterial communities during di-(2-ethylhexyl) phthalate (DEHP) degradation in a soil microcosm

Four previously isolated di-butyl-phthalate (DBP) degraders were tested for their abilities to degrade di-(2-ethylhexyl) phthalate (DEHP). In aqueous medium supplemented with 100mg/l of DEHP, both isolate G1 and Rhodococcus rhodochrous G2 showed excellent degradative activity; in three days they were able to degrade more than 97% of the added DEHP. Rhodococcus rhodochrous G7 degraded 32.5% of the added DEHP and Corynebacterium nitrilophilus G11 showed the least amount of DEHP degradation. The addition of surfactant Brij 30 at 0.1x critical micelle concentration (2mg/l) significantly improved DEHP degradation by Rhodococcus rhodochrous G2 (more than 90% of the added DEHP was degraded within 24 hours), but slightly inhibited the degradation of DEHP by the isolate G1 and Rhodococcus rhodochrous G7. Based on the 16S rDNA sequence data, isolate G1 was identified as Gordonia polyisoprenivorans. Soil inhibited DEHP degradation by G. polyisoprenivorans G1; fourteen days after a second addition of DEHP, 11.5% of the total added DEHP (i.e., 243.4 microg/g soil) remained detectable. Changes in the bacterial community were monitored using denaturing gradient gel electrophoresis (DGGE) and respective dendrogram analysis. It is clear that DEHP and DEHP plus G. polyisoprenivorans G1 substantially affected the bacterial community structure in the soils. However, as the population of indigenous DEHP degraders increased in the DEPH-treated soil, its bacterial communities resembled those in the DEHP plus G. polyisoprenivorans G1-inoculated soil by Day 17.     

Determination of polycyclic aromatic hydrocarbons and substitutes (Nitro-, Oxy-PAHs) in urban soil and airborne particulate by GC-MS and NCI-MS/MS

A method involving high resolution gas chromatography combined with ion trap (HRGC-MS/MS) and negative chemical ionisation (NCI) was developed for the determination of nitrated or oxygenated polycyclic aromatic hydrocarbons (nitro-PAHs, oxy-PAHs) and other electrophilic substitutes in soil samples. Efficient clean-up was achieved by a combination of methods for the determination of PAHs in soil and nitro-PAHs in aerosol using solid phase extraction (SPE) and semipreparative high performance liquid chromatography (HPLC). In samples of surface soil from the city of Basle (Switzerland), nitro-PAHs (mainly 3-nitrofluoranthene and 1-nitropyrene) were found in concentrations between 30 and 800 ng/kg dry weight. Oxy-PAHs and parent PAHs revealed 10²-10⁴-fold higher levels. Nitro-PAHs which are up to 10⁵ times more mutagenic seem to be less persistent in soil than the parent forms, although their entire mutagenic potential has to be estimated as being on the same order of magnitude. In urban air particulate matter, the amounts of nitro-PAHs (2–62 pg/m³) were 10–100 times lower than oxyPAHs and parent PAHs which were both found in a similar range. 3-nitrobenzanthrone, a recently described suspected human carcinogen has not yet been detected. Using multivariate statistical analysis, it was possible to elucidate similarities or special characteristics of substances in a given matrix reflecting their chemical properties or specific emission sources.     

Effect of the veterinary ionophore monensin on the structure and activity of a tropical soil bacterial community

Abstract

Monensin (MON) is a coccidiostat used as a growth promoter that can reach the environment through fertilization with manure from farm animals. To verify whether field-relevant concentrations of this drug negatively influence the structure and activity of tropical soil bacteria, plate counts, CO₂ efflux measurements, phospholipid fatty acids (PLFA) and community-level physiological profiling (CLPP) profiles were obtained for soil microcosms exposed to 1 or 10?mg kg^?1 of MON across 11?days. Although 53% (1?mg kg^?1) to 40% (10?mg kg^?1) of the MON concentrations added to the microcosms dissipated within 5?days, a subtle concentration-dependent decrease in the number of culturable bacteria (<1 log CFU g^?1), reduced (?20 to ?30%) or exacerbated (+25%) soil CO₂ effluxes, a marked shift of non-bacterial fatty acids, and altered respiration of amines (1.22-fold decrease) and polymers (1.70-fold increase) were noted in some of the treatments. These results suggest that MON quickly killed some microorganisms and that the surviving populations were selected and metabolically stimulated. Consequently, MON should be monitored in agronomic and environmental systems as part of One Health efforts.     

Sorption, degradation and mobility of ptaquiloside, a carcinogenic Bracken (Pteridium sp.) constituent, in the soil environment

Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glucoside produced by Bracken in amounts up to at least 500 mg m(-2). The toxin is transferred from Bracken to the underlying soil from where it may leach to surface and groundwater's impairing the quality of drinking water. The objectives of the present study were to characterize the solubility, degradation and retention of PTA in soils in order to evaluate the risk for groundwater contamination. PTA was isolated from Bracken. The logarithmic octanol-water and ethyl acetate-water partitioning coefficients for PTA were -0.63 and -0.88, respectively, in agreement with the high water solubility of the compound. PTA hydrolysed rapidly in aqueous solution at pH 4 or lower, but was stable above pH 4. Incubation of PTA with 10 different soils at 25 degrees C showed three different first order degradation patterns: (i) rapid degradation observed for acid sandy soils with half life's ranging between 8 and 30 h decreasing with the soil content of organic matter, (ii) slow degradation in less acid sandy soils with half-lives of several days, and (iii) fast initial degradation with a concurrent solid phase-water partitioning reaction observed for non-acid, mostly clayey soils. The presence of clay silicates appears to retard the degradation of PTA, possibly through sorption. Degradation at 4 degrees C was generally of type (iii) and degradation rates were up to 800 times lower than at 25 degrees C. Sorption isotherms for the same set of soils were almost linear and generally showed very low sorption affinity with distribution coefficients in the range 0.01-0.22 l kg(-1) at a solution concentration of 1 mg l(-1) except for the most acid soil; Freundlich affinity coefficients increased linearly with clay and organic matter contents. Negligible sorption was also observed in column studies where PTA and a non-sorbing tracer showed almost coincident break-through. Leaching of PTA to the aqueous environment will be most extensive on sandy soils, having pH >4 and poor in organic matter which are exposed to high precipitation rates during cold seasons.     

Assessing contamination of smoked sprats (Sprattus sprattus) with polycyclic aromatic hydrocarbons (PAHs) and changes in its level during storage in various types of packaging

The analysis of material used in this study demonstrated that the amount of polycyclic aromatic hydrocarbons (PAHs) in smoked sprats varies from the level below the lowest detection limit in muscles up to 9.99 µg kg^?1 of benzo[a]pyrene (BaP) in fish skin. Such a high level of PAHs in skin was reported only in one of six batches of sprats, while mean BaP level was at 1.69 µg kg^?1. Regardless such a high BaP level in skin, its concentration in muscles did not exceed the maximum acceptable level. The study objective was to assess to what extent packaging materials adsorb PAH compounds from food. Changes in the PAH levels were monitored in fish during their storage in packages made of various materials. The storage time was from 0 to 168 hours. The obtained results varied considerably, therefore their scatter did not allow to confirm unequivocally the preliminary hypothesis about the reduction of PAHs due to their migration to packaging material. However, analysis of the packaging used in this study demonstrated a significant increase in the level of total 16 PAHs. When high-density polyethylene (HDPE) packaging was analysed, a six-fold increase in the total 16 PAHs was observed comparing to the blank sample.     

污泥与葡萄糖不同配比联合厌氧消化对污泥中多环芳烃去除效能及细菌群落的影响

为分析污泥与葡萄糖不同配比进行联合厌氧消化对污泥中多环芳烃(PAHs)去除效能及细菌群落的影响,在中温(35±1)℃条件下,以未添加葡萄糖的污泥厌氧消化为对照(CK),研究了活性污泥与葡萄糖按不同有机质含量(挥发性固体(VS)质量比)分别为1∶0.1、1∶0.3和1∶0.5对PAHs去除效能及细菌群落的影响。结果表明,葡萄糖添加量的增加并未进一步提高PAHs的降解能力。P1实验组(VS_(污泥)∶VS_(葡萄糖)=1∶0.1)对消化污泥中∑PAHs的去除能力最强;降解速率可达到(60.56±8.10)%;且高分子质量PAHs(≥4环)的降解速率显著高于低分子质量PAHs(2～3环)(P0.05)。苯并(a)蒽、?、苯并(b)荧蒽和苯并(k)荧蒽的平均降解速率均大于62%;而苯并(a)芘的降解速率达到(59.60±14.05)%。此外,使用16S r RNA技术,检测消化污泥中细菌群落发现,向污泥中添加葡萄糖,可能通过促进Actinobacteria、 Bacteroidetes_vadin HA17、 Spirochaetes、 Planctomycetes和norank_f_Anaerolineaceae菌群的生长,从而提高污泥中PAHs的去除能力。     

Phytotoxicities of fluoranthene and phenanthrene deposited on needle surfaces of the evergreen conifer, Japanese red pine (Pinus densiflora Sieb. et Zucc.)

Polycyclic aromatic hydrocarbons (PAHs) have been widely studied with respect to their carcinogenic and mutagenic effects on animals and human cells. Phenanthrene (PHE) and fluoranthene (FLU) effects on the needle photosynthetic traits of 2-year-old Japanese red pine (Pinus densiflora Sieb. et. Zucc.) seedlings were investigated. Three months after fumigation of foliage with solutions containing these PAHs (10 microM each), FLU had negative effects on net photosynthesis at near-saturating irradiance, stomatal conductance, initial chlorophyll fluorescence, and the contents of total chlorophyll, magnesium, and ribulose 1,5-bisphosphate carboxylase (rubisco) of current-year needles. PHE had similar negative effects to FLU but in lesser magnitude. The effects of the PAHs were mitigated by the addition of an OH-radical scavenger (mannitol) into the PAH solutions. PAHs deposited on the surface of pine needles may induce the generation of reactive oxygen species in the photosynthetic apparatus, a manner closely resembling the action of the herbicide paraquat.     

Effect of Sphingobium yanoikuyae B1 inoculation on bacterial community dynamics and polycyclic aromatic hydrocarbon degradation in aged and freshly PAH-contaminated soils

Sphingobium yanoikuyae B1 is able to degrade a range of polycyclic aromatic hydrocarbons (PAHs) and as a sphingomonad belongs to one of the dominant genera found in PAH-contaminated soils. We examined the ecological effect that soil inoculation with S. yanoikuyae B1 has on the native bacterial community in three different soils: aged PAH-contaminated soil from an industrial site, compost freshly contaminated with PAHs and un-contaminated compost. Survival of S. yanoikuyae B1 was dependent on the presence of PAHs, and the strain was unable to colonize un-contaminated compost. Inoculation with S. yanoikuyae B1 did not cause extensive changes in the native bacterial community of either soil, as assessed by denaturing gel electrophoresis, but its presence led to an increase in the population level of two other species in the aged contaminated soil community and appeared to have an antagonistic affect on several members of the contaminated compost community, indicating niche competition.     

PAH-sequestration capacity of granular and powder activated carbon amendments in soil, and their effects on earthworms and plants

A field lysimeter study was carried out to investigate whether the amendment of 2% powder and granular activated carbon (PAC and GAC) to a soil with moderate PAH contamination had an impact on the PAH bioaccumulation of earthworms and plants, since AC is known to be a strong sorbent for organic pollutants. Furthermore, secondary effects of AC on plants and earthworms were studied through growth and nutrient uptake, and survival and weight gain. Additionally, the effect of AC amendments on soil characteristics like pH, water holding capacity, and the water retention curve of the soil were investigated. Results show that the amendment of 2% PAC had a negative effect on plant growth while the GAC increased the growth rate of plants. PAC was toxic to earthworms, demonstrated by a significant weight loss, while the results for GAC were less clear due to ambiguous results of a field and a parallel laboratory study. Both kinds of AC significantly reduced biota to soil accumulation factors (BSAFs) of PAHs in earthworms and plants. The GAC reduced the BSAFs of earthworms by an average of 47 ± 44% and the PAC amendment reduced them by 72 ± 19%. For the investigated plants the BSAFs were reduced by 46 ± 36% and 53 ± 22% by the GAC and PAC, respectively.     

Long-term effects of liquid swine manure land surface application in an apple orchard field on soil bacterial community and heavy metal contents in apple (Malus pumila Mill.)

Environmental Science and Pollution Research - This study investigated the impact of liquid swine manure (LSM) land surface application in an apple orchard on soil health and copper (Cu) and zinc...     

Assessment of bacterial communities and characterization of lead-resistant bacteria in the rhizosphere soils of metal-tolerant Chenopodium ambrosioides grown on lead-zinc mine tailings

Bacterial communities in the rhizosphere soils of metal tolerant and accumulating Chenopodium ambrosioides grown in highly and moderately lead-zinc mine tailings contaminated-soils as well as the adjacent soils with low metal contamination were characterized by using cultivation-independent and cultivation techniques. A total of 69, 73, and 83 bacterial operational taxonomic units (OTUs) having 84.8-100% similarity with the closest match in the database were detected among high, moderate, and low-contamination soil clone libraries, respectively. These OTUs had a Shannon diversity index value in the range of 4.06-4.30. There were 9, 10, and 14 bacterial genera specific to high, moderate, and low metal-contaminated soil clone libraries, respectively. Phylogenetic analysis showed that the Pb-resistant isolates belonged to 8 genera. Pseudomonas and Arthrobacter were predominant among the isolates. Most of the isolates (82-86%) produced indole acetic acid and siderophores. More strains from the highly metal-contaminated soil produced 1-aminocyclopropane-1-carboxylate deaminase than the strains from the moderately and lowly metal-contaminated soils. In experiments involving canola grown in quartz sand containing 200 mg kg⁻¹ of Pb, inoculation with the isolated Paenibacillusjamilae HTb8 and Pseudomonas sp. GTa5 was found to significantly increase the above-ground tissues dry weight (ranging from 19% to 36%) and Pb uptake (ranging from 30% to 40%) compared to the uninoculated control. These results show that C. ambrosioides harbor different metal-resistant bacterial communities in their rhizosphere soils and the isolates expressing plant growth promoting traits may be exploited for improving the phytoextraction efficiency of Pb-polluted environment.     

光合细菌改善Cd、Pb及呋喃丹污染土壤的微生物群落DNA序列多样性的研究

应用DNA随机扩增多态性(RAPD)分子标记技术研究了光合细菌(PSB)对Cd、Pb及呋喃丹污染土壤的微生物群落DNA序列多样性的影响.结果表明,Cd、Pb及呋喃丹单一污染或3者复合污染土壤的微生物群落DNA序列的丰富度相对对照土样(S0)都有不同程度的增加,受Cd、Pb或呋哺丹污染,可能会引起土壤微生物群落DNA序列...     

Effect of water current on the distribution of polycyclic aromatic hydrocarbons,heavy metals and benthic diatom community in sediments of Haihe estuary,China

The pollution loads continuously increased in Haihe estuary, of Tianjin, China, due to intensive human activities, especially the construction of the Haihe Gate and Lingang Industrial Area. In 2011, hydrological variability in Haihe estuary was investigated and sediments were collected. Total organic carbon (TOC), particle size, total polycyclic aromatic hydrocarbons (ΣPAHs), heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn), and benthic diatom community were analyzed. The highest concentrations of ΣPAHs and heavy metals were found near the Haihe Gate. The Shannon diversity index and the relative abundance of Coscinodiscus perforatus (RC) indicated a decreasing trend seaward. Results of Pearson correlation analysis illustrated significant relations between water current velocity and ΣPAHs (p?p?p?相似文献   

改性秸秆吸附微生物对土壤中石油烃降解及演化特征的影响

以甲基丙烯酸丁酯-苯乙烯改性玉米秸秆（BMGS）为载体吸附微生物对油污土壤进行了模拟降解实验,研究BMGS作为菌剂载体对油污土壤的降解效果,同时利用GC-MS指纹图谱深入分析TPH（total petroleum hydrocarbon）的重要组分——正构烷烃的降解演化规律和特性。结果表明：BMGS具有较高吸油能力（10.3 g·g-1）,大于原秸秆（RMS）5.7 g·g-1;在3%含油量的油污土壤中,加入用BMGS吸附的菌剂的降解半衰期（14.8 d）均短于空白与用原秸秆（RMS）吸附的半衰期（36.1 d和33.0 d）。降解演化特性表明,2种秸秆RMS与BMGS材料对正构烷烃降解的促进作用依次提高,主峰碳数均出现前移,且BMGS的效果更为明显。加入BMGS后有利于菌剂降解较难降解的偶碳数正构烷烃和类异戊二烯烷烃,并且在降解前、后期,对低、高碳数正构烷烃的降解优势完成增效作用,高碳数正构烷烃平均降解率达到91.25%,较好地解释BMGS吸附菌剂后可以缩短降解TPH半衰期及提高降解率的原因。     

Impact of soil organic matter on the distribution of polycyclic aromatic hydrocarbons (PAHs) in soils

The knowledge on the distribution of hydrophobic organic contaminants in soils can provide better understanding for their fate in the environment. In the present study, the n-butanol extraction and humic fractionation were applied to investigate the impact of SOM on the distribution of polycyclic aromatic hydrocarbons (PAHs). The results indicated that 80.5%-94.8% of the target PAHs could be extracted by n-butanol and 63.1%-94.6% of PAHs were associated with fulvic acid (FA). Concentrations of un-extracted PAHs increased significantly with the increasing soil organic matter (SOM), however, such an association was absent for the extractable fractions. The results suggested that the sequestration played a critical role in the accumulation of PAHs in soils. SOM also retarded the diffusion of PAHs into the humin fractions. It implied that sequestration in SOM was critical for PAH distribution in soils, while the properties of PAH compounds also had great influences.     

Heavy metal pollution exerts reduction/adaptation in the diversity and enzyme expression profile of heterotrophic bacteria in Cochin estuary, India

Over the past three decades heavy metal pollution has increased substantially in Cochin estuary, south west coast of India. Here we studied the distribution, diversity and enzyme expression profile of culturable microbial population along a pollution gradient. The distribution of resistance against 5 mM concentration of Zn, Co, Ni and Cu was observed among 90-100% of bacterial isolates retrieved from highly polluted Eloor, whereas it was less than 40% in Vypin and Munambam. Similarly, there was a difference in the distribution and diversity of bacterial phyla with predominance of Proteobacteria in Eloor and Firmicutes in Munambam and Vypin. We observed that 75-100% of the organisms retrieved from Eloor had low levels of expression for hydrolytic enzyme. In conclusion, the heavy metal pollution in Cochin estuary brought in reduction/adaptation in the distribution, diversity and enzyme expression profile of bacteria, which may impart adverse impacts on ecosystem functioning.     

腐植酸对多环芳烃在污染土壤中淋出及截留分解的效果研究

多环芳烃是固废拆解地一类污染较严重的有毒有机物质,用腐植酸作表面活性剂淋洗污染土壤起到较好的增溶及截留分解污染物的作用,达到修复污染土壤的目的。实验结果表明,随着腐植酸加入量的增加,菲、萘、荧蒽、芘和∑PAHs的淋出量显著提高,在污染红壤中最大淋出率分别为52.9%、70.1%、30.5%、46.1%和42.8%,在污染水稻土中最大淋出率分别为51.8%、67.3%、35.0%、38.3%和35.5%,同时多环芳烃的截留分解率也相对较高,而污染红壤和水稻土的总修复率分别达到56.3%和49.8%。     

Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil

Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg⁻¹) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC₅₀ values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC₅₀ concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs.