Resistance of aerobic microorganisms and soil enzyme response to soil contamination with Ekodiesel Ultra fuel

This study determined the susceptibility of cultured soil microorganisms to the effects of Ekodiesel Ultra fuel (DO), to the enzymatic activity of soil and to soil contamination with PAHs. Studies into the effects of any type of oil products on reactions taking place in soil are necessary as particular fuels not only differ in the chemical composition of oil products but also in the composition of various fuel improvers and antimicrobial fuel additives. The subjects of the study included loamy sand and sandy loam which, in their natural state, have been classified into the soil subtype 3.1.1 Endocalcaric Cambisols. The soil was contaminated with the DO in amounts of 0, 5 and 10 cm³ kg⁻¹. Differences were noted in the resistance of particular groups or genera of microorganisms to DO contamination in loamy sand (LS) and sandy loam (SL). In loamy sand and sandy loam, the most resistant microorganisms were oligotrophic spore-forming bacteria. The resistance of microorganisms to DO contamination was greater in LS than in SL. It decreased with the duration of exposure of microorganisms to the effects of DO. The factor of impact (IF_DO) on the activity of particular enzymes varied. For dehydrogenases, urease, arylsulphatase and β-glucosidase, it had negative values, while for catalase, it had positive values and was close to 0 for acid phosphatase and alkaline phosphatase. However, in both soils, the noted index of biochemical activity of soil (BA) decreased with the increase in DO contamination. In addition, a positive correlation occurred between the degree of soil contamination and its PAH content.

     

废橡胶制备燃料油和炭黑

介绍了由废旧橡胶通过催化裂解制备燃料油和炭黑的方法,着重探讨了影响燃料油产率的因素,结果表明在优化条件下燃料油收率达42％,炭黑纯度在97％以上。     

The effects of heavy metal contamination on the soil arthropod community of a shooting range

Soils in clay pigeon shooting ranges can be seriously contaminated by heavy metals. The pellets contained in ammunition are composed of Pb, Sb, Ni, Zn, Mn and Cu. The total concentrations of these metals in soils, and the effects of their increasing levels on the arthropod community were investigated at seven sampling sites in a clay pigeon shooting range and compared with two controls. Research revealed that the spatial distribution of Pb and Sb contamination in the shot-fall area was strongly correlated with the flight path of the pellets. Ordination obtained through Redundance Analysis showed that Collembola, Protura and Diplura were positively correlated with major detected contaminants (Pb, Sb), while Symphyla showed a negative correlation with these pollutants. Determination of the soluble lead fraction in soil, and of its bioaccumulation in the saprophagous Armadillidium sordidum (Isopoda) and the predator Ocypus olens (Coleoptera), showed that a significant portion of metallic Pb from spent pellets is bioavailable in the soil and can be bioaccumulated by edaphic organisms, entering the soil trophic network, but without biomagnification.     

Oxygenated fuel induced cosolvent effects on the dissolution of polynuclear aromatic hydrocarbons from contaminated soil

The cosolvent-induced dissolution of polynuclear aromatic hydrocarbons (PAHs) from contaminated soil caused by oxygenated fuel spills was studied. Oxygenated fuel induces a solvent flushing effect on the contaminated soil due to the high content of oxygenated compounds (i.e., methanol, ethanol, and methyl tert butyl ether (MTBE)). The miscible displacement techniques were applied to evaluate the increased potential for secondary contamination in an impacted site. Significant solubility enhancement of the 18 PAHs monitored during fuel spill simulation and cosolvent flushing is clearly evident when compared to normal water dissolution. The breakthrough concentration profile for each PAH constituent was integrated over the cumulative effluent volume (i.e., the zeroth moment) to determine the total PAH mass removed during the experiment. The removal efficiency of PAHs ranges from 46.6% to 99.9% in three oxygenated fuels (i.e., M85, E85, and oxygenated gasoline) during the fuel spill. Several factors including hydrophobicity of compounds, nonequilibrium dissolution due to nonuniform coal tar distribution, and heterogeneous media properties affect the oxygenated compound-induced dissolution process. This study provides a basis to predict the facilitated transport of hydrophobic organic compounds from subsurface environment due to the cosolvent effects of oxygenated fuels.     

微生物燃料电池修复石油污染盐碱土壤

生物电化学技术修复石油污染土壤并同步产出电能是一种新兴的污染土壤生态修复技术。对石油污染土壤通过其微生物燃料电池的构造,利用电化学阻抗谱分析了土壤的欧姆内阻,拟合估算了土壤的电导率,并考察了土壤微生物燃料电池的产电性能和修复效果。结果表明：采用丙酮清洗过的阳极并有水封的情况下,土壤微生物燃料电池的欧姆内阻下降了52%,电导率升高了1倍;在启动后的120 h内,最大电压和累计产出电量分别达189 mV和36 C,与对照相比分别增加了20和29倍。输出电压随着阴极与阳极之间距离的增大而减小。经过30 d的生物电化学处理,土壤中的总石油烃去除率是开路对照的3.3倍。该研究是石油污染盐碱土壤生物电化学修复的初步探索,以为污染土壤的生态修复提供新的思路。     

The organic contamination level based on the total soil mass is not a proper index of the soil contamination intensity

Concentrations of organic contaminants in common productive soils based on the total soil mass give a misleading account of actual contamination effects. This is attributed to the fact that productive soils are essentially water-saturated, with the result that the soil uptake of organic compounds occurs principally by partition into the soil organic matter (SOM). This report illustrates that the soil contamination intensity of a compound is governed by the concentration in the SOM (C_om) rather than by the concentration in whole soil (C_s). Supporting data consist of the measured levels and toxicities of many pesticides in soils of widely differing SOM contents and the related levels in in-situ crops that defy explanation by the C_s values. This SOM-based index is timely needed for evaluating the contamination effects of food crops grown in different soils and for establishing a dependable priority ranking for intended remediation of numerous contamination sites.     

Removal of volatile and semivolatile organic contamination from soil by air and steam flushing

A soil core, obtained from a contaminated field site, contaminated with a mixture of volatile and semivolatile organic compounds (VOC and SVOC) was subjected to air and steam flushing. Removal rates of volatile and semivolatile organic compounds were monitored during flushing. Air flushing removed a significant portion of the VOC present in the soil, but a significant decline in removal rate occurred due to decreasing VOC concentrations in the soil gas phase. Application of steam flushing after air flushing produced a significant increase in contaminant removal rate for the first 4 to 5 pore volumes of steam condensate. Subsequently, contaminant concentrations decreased slowly with additional pore volumes of steam flushing. The passage of a steam volume corresponding to 11 pore volumes of steam condensate reduced the total VOC concentration in the soil gas (at 20 degrees C) by a factor of 20 to 0.07 mg/l. The corresponding total SVOC concentration in the condensate declined from 11 to 3 mg/l. Declines in contaminant removal rates during both air and steam flushing indicated rate-limited removal consistent with the persistence of a residual organic phase, rate-limited desorption, or channeling. Pressure gradients were much higher for steam flushing than for air flushing. The magnitude of the pressure gradients encountered during steam flushing for this soil indicates that, in addition to rate-limited contaminant removal, the soil permeability (2.1 x 10(-9) cm2) would be a limiting factor in the effectiveness of steam flushing.     

Effect of soil on microbial responses to metal contamination

An experiment was conducted to investigate microbial responses to metal inputs in five soils with varying clay and organic contents; one soil had also a higher pH. These soils were treated with a low metal, sewage sludge control or with this sludge contaminated to achieve Cu=112, Ni=58 and Zn=220 mg kg(-1) in medium and Cu=182, Ni=98 and Zn=325 mg kg(-1) in high metal soils. CO(2) evolution rates were measured at 1 week and at 4-5-day intervals thereafter until the end of the incubation (7 weeks). Extractable metals (CaCl(2) and water), biomass C, metabolic quotient, ergosterol, bacterial-fungal phospholipid fatty acid (PLFA-3 weeks only) ratio and mineral N were measured at 3 and 7 weeks. Metal inputs caused a marked increase in metal availability in the slightly acidic sandy loams, a smaller increase in slightly acidic clays and had little effect in the alkaline loam. After an initial increase in CO(2) evolution with metal inputs in all soils, the high metal treatment alone caused a significant decrease at later stages, mainly in sandy loams. Although biomass C and metabolic quotient decreased in all soils with higher metal inputs, the effect was more pronounced in the sandy loams. Metal inputs increased ergosterol and decreased bacterial-fungal PLFA ratios in most soils. Larger mineral N contents were found in all high metal soils at 3 weeks but, after 7 weeks, metals caused a significant decrease in sandy loams. CaCl(2) and water-extractable Cu, Ni and Zn contents were closely correlated with microbial indices in sandy loam but not in clay soils. Overall, the effect of treatments on microbial and extractable metal indices was greater in loams. Within a single series, higher organic soils showed less pronounced responses to metal inputs, although this trend was not always consistent.     

土壤石油烃污染的植物毒性及植物-微生物联合降解

通过盆栽实验研究了土壤石油烃污染对玉米和水稻根伸长的影响,并在土壤中接种经过筛选得到的石油烃降解菌,研究石油烃降解菌对石油烃毒性的影响以及对土壤中石油烃的降解。研究结果表明,石油烃浓度低于1 000 mg/kg时对玉米的根系生长有一定的刺激生长作用,随着石油烃浓度的增加,刺激根长生长的作用逐渐降低,研究结果表明,水稻根长受石油烃影响较小。通过对不同处理土壤中石油烃降解的研究结果表明,土壤中种植水稻对石油烃有一定的降解作用,但是不同处理下土壤中的石油烃降解率不同,其中水稻微生物联合处理下土壤中石油烃的降解速率最快,培养期内的降解效率达到53.3%。     

Matrix effects in applying mono- and polyclonal ELISA systems to the analysis of weathered oils in contaminated soil

Commercial mono- and polyclonal enzyme-linked immunosorbent assay (ELISA) systems were applied to the on-site analysis of weathered hydrocarbon-contaminated soils at a former integrated steelworks. Comparisons were made between concentrations of solvent extractable matter (SEM) determined gravimetrically by Soxhlet (dichloromethane) extraction and those estimated immunologically by ELISA determination over a concentration range of 2000-330,000 mg SEM/kg soil dry weight. Both ELISA systems tinder-reported for the more weathered soil samples. Results suggest this is due to matrix effects in the sample rather than any inherent bias in the ELISA systems and it is concluded that, for weathered hydrocarbons typical of steelworks and coke production sites, the use of ELISA requires careful consideration as a field technique. Consideration of the target analyte relative to the composition of the hydrocarbon waste encountered appears critical.     

Geostatistical analysis of soil contamination in the Swiss Jura

The topsoil of a 14.5 km(2) region of the Swiss Jura has been surveyed to identify the distributions of trace metals in it. The soil was sampled at 366 sites selected by combining a square grid and nesting. Concentrations of seven potentially toxic metals, namely Cd, Co, Cr, Cu, Ni, Pb and Zn, were measured. Land use and geology (stratigraphy) were also recorded. Variograms were bounded in the range from 110 m to 1500 m with contributions to the variance at all distances exceeding 6 m. The variograms of Cd, Cr, Cu and Pb are dominated by short range correlation, those of Co and Ni by correlation of long range, and Zn is intermediate. The concentrations were estimated at the nodes of a fine grid by ordinary block kriging and then contoured to produce maps. The maps of Co and Ni have a coarse patchy pattern similar to that of the geology, suggesting that these metals derive from the bedrock. This is supported by analysing the variance by geology. Copper and Pb have finer patterns of distribution, and are more likely to have been added with fertilizer or manure or domestic waste. Cadmium could originate from human activities, such as smelters or fertilizer spreading, or from specific geological deposits, such as moraine.     

Effects of chronic low-level PAH contamination of soil invertebrate communities

Soils containing low levels of polycyclic aromatic hydrocarbons (PAHs) were collected from an abandoned industrial site. A study was conducted to evaluate the effects of these contaminants on soil invertebrates representing three levels of ecological hierarchy: the microfauna, mesofauna, and macrofauna. Nematodes were studied as representatives of the soil microfauna, microarthropods as representatives of the mesofauna, and earthworms as representatives of the macrofauna. Six sample plots representing a gradient of PAH contamination ranging from 5.28 to 80.46 mg/kg total PAHs were evaluated. Nematode community structure, including abundance and diversity of trophic and taxonomic groups; the total abundance of microarthropods (orders Collembola and Acarina); and earthworm (Eisenia andrei) growth were evaluated. Multiple regression analyses were used to evaluate trends in the responses of these target organisms to PAH concentrations and habitat variability. Abundance of omnivore/predator nematodes and microarthropod order Collembola; nematode taxonomic diversity; and the percent difference in earthworm weights exhibited positive associations with PAH concentrations. Total abundance of microarthropod order Acarina was negatively associated with PAH concentrations.     

Environmental protection and energy efficiency improvement by using natural gas fuel in maritime transportation

Environmental Science and Pollution Research - Emissions from vessels are a major environmental concern because of their impacts on the deterioration of the environment, especially global warming...     

Principal component analysis for soil contamination with organochlorine compounds

In order to investigate the distribution pattern of individual organochlorine compounds in soil samples collected from the sites (Canary Island – Spain, China, Germany, India, Romania, Russia, Serbia, Swiss, UK) affected by industrial activities to the more remote areas, principal component analysis was performed on the data taken from literature. Loading plots pointed out the strong correlation among the variables. Score plots revealed similar PCB- and OCP-soil patterns for majority of the investigated sites. Nevertheless, the temporal differences of PCB-soil loads have been identified: the late 1990s and early 2000s concentrations are similar to those of the early 1940s, and they are below the levels existed in 1980. The most pronounced PCB concentrations characterized the soil from 1966. For OCPs the influence of sites location on the detected concentration has been revealed: China and India were characterized by comparably higher loads of DDX (DDT and its metabolites) and of HCH-isomers, respectively.     

The sensitivity of soil enzymes,microorganisms and spring wheat to soil contamination with carfentrazone-ethyl

Herbicides pose a significant threat to the natural environment, in particular in soils that are most exposed to plant protection agents. Prolonged herbicide use leads to changes in soil metabolism and decreases soil productive potential. In this study, the influence of carfentrazone-ethyl (CE) on the microbiological and biochemical properties of soil and the yield of Triticum aestivum L. was evaluated. Carfentrazone-ethyl was applied to sandy loam (pH_KCl – 7.0) in doses of 0.000, 0.264, 5.280, 10.56, 21.18, 42.24, 84.48 and 168.96 µg kg^?1 DM soil. Soil samples were subjected to microbiological and biochemical analyses on experimental days 30 and 60. Carfentrazone-ethyl disrupted the biological equilibrium in soil by decreasing the abundance and biodiversity of soil-dwelling microorganisms, the activity of soil enzymes, the values of the biochemical activity indicator and spring wheat yields. Carfentrazone-ethyl had the most adverse effects when applied in doses many fold higher than those recommended by the manufacturer. The toxic effects of CE were also determined by its soil retention time. Soil treated with CE was characterized by higher counts of oligotrophic bacteria, organotrophic bacteria, bacteria of the genus Azotobacter, actinomycetes and fungi on day 60, and spore-forming oligotrophic bacteria on day 30. The activity of dehydrogenases, urease, alkaline phosphatase and β-glucosidase was higher on day 30 than on day 60.     

Polycyclic aromatic hydrocarbon contamination in an urban area assessed by Quercus ilex leaves and soil

We investigated the PAH contamination of Naples urban area, densely populated and with high traffic flow, by analyses of environmental matrices: soil and Quercus ilex leaves. Being some PAHs demonstrated to have hazardous effects on human health, the accumulation of carcinogenic and toxic PAHs (expressed as B(a)Peq) was evaluated in the leaves and soil. The main sources of the PAHs were discriminated by the diagnostic ratios in the two matrices. The urban area appeared heavily contaminated by PAHs, showing in soil and leaves total PAH concentrations also fivefold higher than those from the remote area. The soil mainly accumulated heavy PAHs, whereas leaves the lightest ones. Median values of carcinogenic PAH concentrations were higher in soil (440 ng g^?1 d.w.) and leaves (340 ng g^?1 d.w.) from the urban than the remote area (60 and 70 ng g^?1 d.w., respectively, for soil and leaves). Also, median B(a)Peq concentrations were higher both in soil and leaves from the urban (137 and 63 ng g^?1 d.w., respectively) than those from the remote area (19 and 49 ng g^?1 d.w., respectively). Different from the soils, the diagnostic ratios found for the leaves discerned PAH sources in the remote and urban areas, highlighting a great contribution of vehicular traffic emission as main PAH source in the urban area.     

氯化铁和硫酸铁对酸性土壤中有效态镉和铅污染的修复作用

采用浸泡实验法研究了氯化铁和硫酸铁对酸性土壤中有效态镉和铅污染的修复效果,结果表明,氯化铁和硫酸铁均能有效去除土壤有效态镉和铅污染,Fe(Ⅲ)用量为50~100 mmol/kg时,有效态Cd和Pb的去除效果可达70%~96%。氯化铁和硫酸铁能去除土壤中的水溶态、碳酸盐结合态、腐殖酸结合态、铁锰氧化物结合态和强有机结合态Cd和Pb及交换态Cd。氯化铁和硫酸铁对Cd均既有洗脱修复作用又有固定修复作用,且洗脱修复作用的贡献稍大;氯化铁用量较小时(50 mmol/kg)对Pb既有固定修复又有洗脱修复作用,固定修复作用稍大;用量较大时(100 mmol /kg),对Pb只有洗脱修复作用。硫酸铁对Pb的修复作用则以固定修复作用为主,洗脱修复作用很小。     

Patterns of metal soil contamination and changes in terrestrial cryptogamic communities

Correlations between terricolous bryophyte- and lichen- vegetation and edaphic parameters (pH, organic matter, nitrogen, Carbon/nitrogen ratio, Cation Exchange Capacity, and Cd, Pb and Zn soil contents) of soils submitted to a gradient of metal contamination in northern France were performed using statistical analysis. Six classes can be distinguished according to the low-, intermediate- and high-trace metal levels respectively, leading to the conclusion that bryophyte- and lichen-groupings have a strong bioindicative value of the heavy metal pollution of soils.     

Evaluation of various tests for the diagnosis of soil contamination by 2,4,5-trichlorophenol (2,4,5-TCP)

Soil response to contamination with 2,4,5-triclorophenol was studied to test the validity of the concept of Generic Reference Levels (GRL), the main criterion used to define soil contamination. Soil samples were artificially contaminated with doses between 0 and 5000 mg kg⁻¹ of 2,4,5-triclorophenol, and analysed by various tests. Where possible, the response of soils to the contaminant was modelled by a sigmoidal dose-response curve in order to estimate the ED₅₀ values. The tests provided different responses, but only microbial biomass-C and dehydrogenase and urease activities demonstrated soil deterioration in response to contamination. The results suggest that the diagnosis of soil contamination has been greatly simplified in the legislation by the provision of a single figure for each compound, and that the GRL concept could perhaps be substituted by measurement of ED₅₀ values, which better reflect the alteration of a soil due to the presence of a xenobiotic substance.