Ecotoxicological testing with new kinetic Photorhabdus luminescens growth and luminescence inhibition assays in microtitration scale

Miniaturized luminescence and growth inhibition assays in microtitration plates with the terrestric enthomopathogenic nematode symbiont Photorhabdus luminescens (DSMZ 3368T) are presented and compared with standardized tests with Vibrio fischeri (DSMZ 7151/NRRLB-11177) and Pseudomonas putida (DSMZ 50026). Toxicological parameters (EC and G values) of selected reference toxicants (e.g. heavy metals and environmental samples) were obtained at different temperatures and without sodium chloride supplementation. Kinetic data recordings were compared with results of a cuvette test protocol using integral and endpoint calculation. Growth inhibition experiments with reference samples reveal similar or higher sensitivities as for the Vibrio or Pseudomonas spp. The luminescence inhibition assay shows reduced sensitivities to most of the reference samples compared with the V. fischeri standard assay. But G values obtained with other standardized aquatic assay systems with daphnids, algae and growth inhibition assays with V. fischeri and Ps. putida correspond more closely to data observed with Ph. luminescens. The test procedures are easily to perform and to evaluate and seem to be reliable alternatives to the established protocols at low osmolarities. The sample specifity of the toxic responses of the marine and the terrestric strain recommends to employ both assays to determine the toxic potential of environmental samples. This will support to reduce false positive results in future investigations.     

Digital innovation through partnership between nature conservation organisations and academia: A qualitative impact assessment

Nature conservation organisations increasingly turn to new digital technologies to help deliver conservation objectives. This has led to collaborative forms of working with academia to spearhead digital innovation. Through in-depth interviews with three UK research-council-funded case studies, we show that by working with academics conservation organisations can receive positive and negative impacts, some of which cut across their operations. Positive impacts include new ways of engaging with audiences, improved data workflows, financial benefits, capacity building and the necessary digital infrastructure to help them influence policy. Negative impacts include the time and resources required to learn new skills and sustain new technologies, managing different organisational objectives and shifts in working practices as a result of the new technologies. Most importantly, collaboration with academics was shown to bring the opportunity of a profound change in perspectives on technologies with benefits to the partner organisations and individuals therein.     

Multiple resistance of acetolactate synthase and protoporphyrinogen oxidase inhibitors in Euphorbia heterophylla biotypes

Resistance to acetolactate synthase (ALS)-inhibiting herbicides in Brazil has been documented for six species. The probability to select biotypes of Euphorbia heterophylla (EPPHL) with multiple resistance increases in the same order of magnitude as the use of other herbicides belonging to only one mechanism of action. The objectives of this work were to evaluate the distribution of resistant populations (R) in the states of the Parana and Santa Catarina; to determine the existence of populations of EPHHL with multiple resistance to ALS and PROTOX inhibitors, and to confirm the occurrence of cross resistance to compounds of these mechanisms of action. Seeds of EPHHL of areas with suspected resistance had been sampled in 97 places during 2003. In the greenhouse experiment samples of each population were sprayed with imazethapyr or fomesafen, at only one rate. To identify the resistant ones they were sprayed with different levels of the herbicides imazethapyr and fomesafen. Later they were sprayed with diverse herbicides of the same mechanisms of action to confirm the multiple/cross resistance. There is widespread distribution in the region of populations with resistance to ALS inhibitors. Some biotypes demonstrated resistance to herbicides from the two mechanisms of action. The resistance factor (FR), or the relation of resistance between R and susceptible biotypes, confirms the existence of two biotypes of EPHHL with cross resistance to several herbicides inhibitors of ALS and PROTOX.     

Phytotoxicity to and uptake of RDX by rice

Phytoremediation is an emerging strategy to remediate soils contaminated with pollutants like explosives in which plants will uptake, degrade and/or accumulate pollutants. To implement this technology on a site contaminated with RDX, we chose rice, which is able to grow in lagoons, and we tested its ability to grow in soils with high levels of RDX and to decrease RDX concentrations in soil. Rice was grown for 40 days in soil contaminated with increasing [14C]RDX concentrations. Emergence and growth were not affected by RDX. Total chlorophyll content decreased with RDX concentrations of over 500 mg kg(-1). Amounts of chlorophyll were correlated with the appearance of necrosis in leaf extremities. After 40 days, rice translocated 89% of uptaken radioactivity to leaves with 90% in leaf extremities. Analyzes of leaf extracts showed that 95% of radioactivity was RDX in its parent form. Necrosis appears to be a phytotoxic symptom of RDX accumulation.     

Degradation of ethylene glycol using Fenton's reagent and UV

Oxidation of ethylene glycol in aqueous solutions was found to occur with the addition of Fenton's reagent with further conversion observed upon UV irradiation. The pH range studied was 2.5-9.0 with initial H2O2 concentrations ranging from 100 to 1000 mg/l. Application of this method to airport storm-water could potentially result in reduction of chemical oxygen demand by conversion of ethylene glycol to oxalic and formic acids. Although the amount of H2O2 added follows the amount of ethylene glycol degraded, smaller H2O2 doses were associated with increases in the ratio of ethylene glycol removed per unit H2O2 added indicating the potential of pulsed doses or constant H2O2 feed systems. Ethylene glycol removal was enhanced by exposure to UV light after treatment with Fenton's reagent, with rates dependent on initial H2O2 concentration. In addition to ethylene glycol, the principle products of this reaction, oxalic and formic acids, have been shown to be mineralized in other HO generating systems presenting the potential for ethylene glycol mineralization in this system with increased HO* production.     

Heavy metal contamination of roadside soils in the Greater Athens area

The airborne contamination of roadside soils with Pb, Cd, Zn and Ni was evaluated for the Greater Athens Area of Greece. High levels of lead enrichment were found in the upper 0-5 cm soil layer along roads with heavy traffic loads. The central section of the study area appeared to have soils with the highest levels of lead enrichment. The contamination decreased exponentially with the distance from the road edge and dropped to a background level at about 50 m. Most of the lead was concentrated in the upper 5 cm of the soil and was associated with carbonates and crystalline oxides. The main source of contamination was automobile exhausts. Roadside soils were also enriched with airborne Cd and Zn, but to a lesser degree than with Pb. The enrichment of the soil with these two elements fell rapidly and exponentially with distance. No evidence of Ni contamination of roadside soils was obtained.     

Experimental determination of the kinetic rate law for the oxidation of perchloroethylene by potassium permanganate

Flushing soils contaminated with trichloroethylene (TCE) and perchloroethylene (PCE) with a permanganate (MnO₄⁻) solution has been shown to reduce the solvent content of the soil. Experiments were performed to quantify the rate at which KMnO₄ oxidizes aqueous solutions of PCE over a range of concentrations. In a series of homogeneous reactors, aqueous phase PCE concentrations were monitored over time in nine experimental trials with excess oxidant concentrations ranging from 5 to 30 g/l. Analysis of the data was performed to quantify the oxidation reaction order with respect to PCE and KMnO₄ and the reaction rate constant. The reaction between PCE and KMnO₄ was determined to be first-order with respect to both PCE and KMnO₄ with an overall specific reaction rate coefficient of 2.45±0.65 M⁻¹ min⁻¹.     

Time-resolved measurements of aerosol elemental concentrations in indoor working environments

We have measured the elemental concentrations in aerosols with a 2-h time resolution in two different types of working environment: a chemistry laboratory dealing with the processing of advanced nanoparticulate materials and a medium-sized machine workshop. Non-stop 10-day and 12-day samplings were performed at each location in order to determine the concentration trends during the non-working/working and weekday/weekend periods. Supplementary measurements of PM10 aerosols with a 2-day sample collection time were performed with a standard Gent PM10 sampler to compare the elemental concentrations with the time-averaged concentrations detected by the 2D step-sampler. The concentrations were determined a posteriori by analyzing the x-ray spectra of aerosol samples emitted after 3-MeV proton bombardment. The PM10 samples collected in the chemistry laboratory were additionally inspected by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) to determine the chemical compositions of the individual particles. In the workshop, a total PM10 mass sampling was performed simultaneously with a minute resolution to compare the signal with typical outdoor PM10 concentration levels. A factor analysis of the time-resolved dataset points to six and eight factors in the chemistry laboratory and the machine workshop, respectively. These factors describe most of the data variance, and their composition in terms of different elements can be related to specific indoor activities and conditions. We were able to demonstrate that the elemental concentration sampling with hourly resolution is an excellent tool for studying the indoor air pollution. While sampling the total PM10 mass concentration with a minute resolution may lack the potential to identify the emission sources in a “noisy” environment, the time averaging on a day time scale is too coarse to cope with the working dynamics, even if elemental sensitivity is an option.     

The effect of resuspending sediment contaminated with antifouling paint particles containing Irgarol 1051 on the marine macrophyte Ulva intestinalis

The effect of resuspending sediment contaminated with Irgarol 1051 based antifouling paint particles on the green macroalga Ulva intestinalis was examined. U. intestinalis was also exposed to sediment spiked with Irgarol 1051. The macroalga were exposed over 21 days to the resuspension of sediments containing 61.2 mg kg(-1) of antifouling paint particles containing Irgarol 1051 that provided aqueous Irgarol 1051 concentrations of approximately 0.3 microg l(-1), Irgarol 1051 and appropriate controls. The growth response was compared with that for 'clean' sediment. Resuspension of sediment was associated with reduced growth when compared to seawater alone. Resuspension of sediment spiked with Irgarol 1051 was associated with a greater reduction in growth, with growth being significantly reduced when sediment containing antifouling paint particles was resuspended. The data suggest that the prolonged disturbance of sediments containing antifouling paint particles in marinas represents a potential and as yet unquantified hazard to photosynthetic organisms.     

Application of capillary electrophoresis combined with a modified BCR sequential extraction for estimating of distribution of selected trace metals in PM2.5 fractions of urban airborne particulate matter

The capillary electrophoresis (CE) method combined with a sequential extraction was applied to determine the distribution of Fe, Zn, Cu, Mn and Cd in urban ambient air PM2.5 samples. PM2.5 was collected on Teflon filters with dichotomous sampler, and the modified extraction procedure following the BCR leaching procedure was used to chemically fractionate metals into "easily exchangeable" with water, "acid extractable" with 0.11 mol/l acetic acid, "reducible" with 0.1 mol/l hydroxylamine hydrochloride acidified to pH 2.0 with nitric acid, and "oxidisable" with oxidation by 8.8 mol/l hydrogen peroxide (H2O2) followed by extraction with 1.0 mol/l ammonium acetate. Based on the obtained results it was concluded that the application of the studied methodology provides chemical fractionation data that reflect the general sources and potential health hazards of the studied metals.     

Phosphorus leaching in soils amended with piggery effluent or lime residues from effluent treatment

Phosphorus (P) in wastes from piggeries may contribute to the eutrophication of waterways if not disposed of appropriately. Phosphorus leaching, from three soils with different P sorption characteristics (two with low P retention and one with moderate P retention) when treated with piggery effluent (with or without struvite), was investigated using batch and leaching experiments. The leaching of P retained in soil from the application of struvite effluent was determined. In addition, P leaching from lime residues (resulting from the treatment of piggery effluent with lime to remove P) was determined in comparison to superphosphate when applied to the same three soils. Most P was leached from sandy soils with low P retention when effluent with or without struvite was applied. More than 100% of the filterable P applied in struvite effluent was leached in sandy soils with low P retention. Solid, inorganic forms of P (struvite) became soluble and potentially leachable at pH<7 or were sorbed after dissolution if there were sufficient sorption sites. In sandy soils with low P retention, more than 39% of the total filterable P applied in recycled effluent (without struvite) was leached. Soil P increased mainly in surface layers after treatment with effluent. Sandy soils pre-treated with struvite effluent leached 40% of the P retained in the previous application. Phosphorus decreased in surface layers and increased at depth in the soil with moderate P retention after leaching the struvite effluent pre-treated soil with water. The soils capacity to adsorb P and the soil pH were the major soil properties that affected the rate and amount of P leaching, whereas the important characteristics of the effluent were pH, P concentration and the forms of P in the effluent. Phosphorus losses from soils amended with hydrated lime and lime kiln dust residues were much lower than losses from soils amended with superphosphate. Up to 92% of the P applied as superphosphate was leached from sandy soils with low P retention, whereas only up to 60% of the P applied in lime residues was leached. The P source contributing least to P leaching was the lime kiln dust residue. The amount of P leached depended on the water-soluble P content, neutralising value and application rate of the P source, and the pH and P sorption capacity of the soil.     

Germany

ABSTRACT

The 1988 Alternative Motor Fuels Act and the 1990 Clean Air Act Amendments require examination of the potential to favorably influence air quality by changing the composition of motor vehicle fuels. Motor vehicle tailpipe and evaporative emissions were characterized using laboratory simulations of roadway driving conditions and a variety of vehicle-fuel technologies (reformulated gasoline (RFG), methanol (M85), ethanol (E85), and natural gas (CNG)). Speciated organic compound (with Carter MIR ozone potential), CO, and NO_x emission rates and fuel economy were characterized. The Carter MIR ozone potential of combined Federal Test Procedure (FTP) tailpipe and evaporative emissions was reduced more than 90% with CNG relative to RFG, M85, and E85 fuels. FTP toxic compound emissions (benzene, formaldehyde, acetalde-hyde, and 1,3-butadiene) were greater with M85 and E85 fuels than with RFG fuel, and less with CNG fuel than RFG fuel. The most abundant toxic compound was benzene with RFG fuel, formaldehyde with M85 fuel, and acetaldehyde with E85 fuel. FTP MPG fuel economies were reduced with M85 and E85 fuels relative to RFG fuel, consistent with their lower BTU/gal. Energy efficiencies (BTU/mi) were improved with all the alternative fuels relative to RFG. Carter MIR ozone potential was generally reduced with the alternative fuels relative to RFG fuel under REP05 (high speeds and acceleration rates) driving conditions (most significantly with CNG). Toxic aldehyde emissions were reduced under REP05 conditions relative to FTP conditions with all the tested fuels, and toxic benzene emissions were elevated under high acceleration conditions.     

Perceived importance of sustainability and ethics related to fish: a consumer behavior perspective

Although sustainability and ethics are of increasing public importance, little research has been conducted to reveal its association with fish consumer behavior. Cross-sectional data were collected through a postal self-administered survey (June 2005) from a sample of 381 Flemish women aged 20-50 years. Consumers attach high perceived importance to sustainability and ethics related to fish. However, this perceived importance is neither correlated with fish consumption frequency nor with general attitude toward eating fish. Refusing to eat wild fish is grounded in sustainability and ethical concerns, whereas the decision not to eat farmed fish is associated with a lower expected intrinsic quality rather than shaped by importance attached to sustainability and ethical issues.     

Dechlorination pathways of ortho-substituted PCBs by UV irradiation in n-hexane and their correlation to the charge distribution on carbon atom

The photodegradations of 22 individual polychlorinated biphenyl (PCB) congeners (including 21 non-coplanar ortho substituted and one non-ortho substituted) by irradiation with ultraviolet lamp in n-hexane solution were studied. Photoproducts were identified by matching their retention times and mass spectra with those of authentic standards. PCB congener with less than two chlorides was photodegraded within half an hour, if more than three chlorine on ring, the photodechlorination time for PCB needs one and half hours or more, sometimes even longer than 15 h. The half-life of PCB degradation by photodechlorination was much shorter than that by anaerobic biological dechlorination. Charge distribution on carbon atom combined with the monitoring products of individual PCB congeners were used to deduce the photodegradation pathways. The higher the charge distribution for carbon to which chlorine is attached, the easier for photodechlorination to occur. A lot of chlorine atoms attached PCB, the dechlorination was found to occur prior to the carbon with higher charge distribution at the benzene ring with more chlorine atoms attached.     

Modeling atmospheric mercury deposition in the vicinity of power plants

Two mathematical models of the atmospheric fate and transport of mercury (Hg), an Eulerian grid-based model and a Gaussian plume model, are used to calculate the atmospheric deposition of Hg in the vicinity (i.e., within 50 km) of five coal-fired power plants. The former is applied using two different horizontal resolutions: coarse (84 km) and fine (16.7 km). More than 96% of the power plant Hg emissions are calculated with the plume model to be transported beyond 50 km from the plants. The grid-based model predicts a lower fraction to be transported beyond 50 km: >91% with a coarse resolution and >95% with a fine resolution. The contribution of the power plant emissions to total Hg deposition within a radius of 50 km from the plants is calculated to be <8% with the plume model, <14% with the Eulerian model with a coarse resolution, and <10% with the Eulerian model with a fine resolution. The Eulerian grid-based model predicts greater local impacts than the plume model because of artificially enhanced vertical dispersion; the former predicts about twice as much Hg deposition as the latter when the area considered is commensurate with the resolution of the grid-based model. If one compares the local impacts for an area that is significantly less than the grid-based model resolution, then the grid-based model may predict lower local deposition than the plume model, because two compensating errors affect the results obtained with the grid-based model: initial dilution of the power plant emissions within one or more grid cells and enhanced vertical mixing to the ground.     

Investigation of appropriate initial composition and aeration method for co-composting of yard waste and market wastes

The purpose of this research was to shorten the composting period by speeding up the composting process and to obtain good quality compost that can be used in agriculture. In order to accomplish the acceleration of the process, different mixtures of feedstock were loaded to the composting containers to observe the effect of initial composition on the quality of the compost and the rate of composting. The first feedstock prepared was composed of grass, leaves and market waste whereas the second feedstock composed only of leaves and market wastes. Composting process was accomplished by applying different composting methods such as composting without manual stirring, with manual stirring, with aeration by air, with aeration by oxygen, with manual stirring and aeration by air and finally by with manual stirring and aeration by oxygen to achieve the purpose of the research. Aeration was found as a primary requirement for the acceleration of composting because it was observed that when the aeration was not applied the conversion of nutrients was very low. The high conversion efficiency of the nutrients in the feedstock with market and yard wastes-without grass-resulted in higher quality end product. The organic content of the composted yard and market wastes were monitored and the best operational parameters and methods were identified. Parameters such as temperature, moisture, pH and end-product metal contents were also monitored in the study. and the experiments were run in duplicates. Corrected C/N, (C/N)t/(C/N)initial, were used in the calculations which provided objectivity in comparison of the compost quality with respect to nutritional components. The C/N change was found to be higher in the container that was manually stirred and aerated with oxygen but with regard to the economic feasibility of the system aeration with air was preferred. Compost quality that was achieved in the study was compared to the standards of different countries with respect to the amount of metal contents in the end-product. The applicability of the end-product in agriculture depends on the level of contaminants in the compost, especially metals that have to be present only in trace amounts.     

Characterization of microbial consortia that reductively dechlorinate 4-chlorophenol and transform phenol to benzoate enriched from estuarine sediment of Lake Shinji

Monochlorophenols were degraded to benzoate via phenol by the initial dechlorination and the subsequent conversion of phenol to benzoate in anaerobic sediment samples of estuarine Lake Shinji under methanogenic conditions. To characterize bacteria that dechlorinate 4-chlorophenol and transform phenol to benzoate, we analyzed the microbial community structure of the enrichment culture with each 4-chlorophenol and phenol by the limiting dilution method with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) of 16S rRNA gene. After serial dilution of the culture, the 4-chlorophenol-dechlorinating culture consisted of two dominant bacteria, one of which was most homologous with Dehalobacter sp. In the enriched culture with phenol, minor band homologous with Cryptanaerobacter phenolicass corresponded to the transformation activity.     

Illuminating reactive microbial transport in saturated porous media: demonstration of a visualization method and conceptual transport model

We demonstrate a method to study reactive microbial transport in saturated translucent porous media using the bacteria Pseudomonas fluorescens 5RL genetically engineered to carry a plasmid with bioluminescence genes inducible by salicylate. Induced bacteria were injected into a cryolite grain filled chamber saturated with a sterile non-growth-promoting (phosphorus limited) chemical mixture containing salicylate as an aromatic hydrocarbon analogue. The amount of light produced by the bacteria serves as an estimator of the relative efficiency of aerobic biodegradation since bioluminescence is dependent on both salicylate and oxygen but only consumes oxygen. Bioluminescence was captured with a digital camera and analyzed to study the evolving spatial pattern of the bulk oxygen consuming reactions. As fluid flow transported the bacteria through the chamber, bioluminescence was observed to initially increase until an oxygen depletion zone developed behind the advective front. Bacterial transport was modeled with the advection dispersion equation and oxygen concentration was modeled assuming bacterial consumption via Monod kinetics with consideration of additional effects of rate-limited mass transfer from residual gas bubbles. Consistent with previous measurements, bioluminescence was considered proportional to oxygen consumed. Using the observed bioluminescence, model parameters were fit that were consistent with literature values and produced results in good agreement with the experimental data. These findings demonstrate potential for using this method to investigate the complex spatial and temporal dynamics of reactive microbial transport in saturated porous media.     

Piezoelectric properties of quartz and cristobalite airborne particulates as a cause of adverse health effects

Inhalation of quartz and cristobalite dusts is commonly linked with health effects although the mechanisms involved are poorly understood. Grinding of these piezoelectric silica polymorphs produces particulates with transient piezoelectric charges. This is likely to cause vigorous reaction with atmospheric gases and, through interaction with surface charges and ‘dangling bonds’, may lead to the formation of highly deleterious ozonide, superoxide and hydroxyl radicals. It is hoped that this study will encourage experimental work to quantify piezoelectric effects in silica dusts and to develop a method for their neutralisation during cutting and grinding processes.     

1-octanol/water distribution coefficient of oxolinic acid: influence of pH and its relation to the interaction with dissolved organic carbon

The distribution of oxolinic acid (OA) between 1-octanol and buffers at a broad range of pH values was studied and found to decrease with increasing pH. The distribution coefficient to dissolved organic carbon (DOC), log DDOC, was estimated and compared with an experimentally derived log DDOC, showing the experimental value to be almost three orders of magnitude higher. Because only the neutral molecule is assumed to distribute to 1-octanol, the interaction with DOC is considered to be electrostatic in character.