Resembling a “natural formation pattern” of chlorinated dibenzo-p-dioxins by varying the experimental conditions of hydrothermal carbonization

Until several years ago dioxins were considered as just an unwanted by product of anthropogenic activities and stigmatized as the symbol of man-made environmental pollution. Natural processes, such as forest fires, can emit dioxins, but compared to industrial processes, usually very low quantities are emitted. However after a case of food contamination occurred in the United States of America in 1996 caused by kaolinitic clay a discussion on the provenience started. Besides the relatively high concentration also an unusual PCDD/F distribution pattern was found in these ball clay samples. This specific pattern related to none of the known anthropogenic sources for these contaminants and, in relation to a supposed natural formation, later it was named “natural formation pattern”. Hydrothermal carbonization (HTC) can transform biomass within hours into a brown coal-like product which resembles naturally occurring coal formation. HTC can also transform an already present PCDD/F contamination in a way to obtain a “natural formation pattern” characterized by an unusual high ratio between 1,2,3,7,8,9-HxCDD and 1,2,3,6,7,8-HxCDD and the absence of almost all chlorinated dibenzofurans. By varying the experimental conditions of the HTC process applied to sewage sludge samples contaminated with PCDD/Fs from anthropogenic sources, beside the “natural formation pattern” at a temperatures of 255 °C, a remarkable increase of the toxicity based on WHO–TEQ was observed.     

Molecular effects and bioaccumulation of levonorgestrel in the non-target organism Dreissena polymorpha

Bioaccumulation and effects of the contraceptive hormone levonorgestrel were examined in the non-target organism Dreissena polymorpha. Molecular biomarkers of biotransformation, elimination, antioxidant defence and protein damage were analyzed after exposure to increasing concentrations of levonorgestrel in a flow-through system. The lowest concentration (0.312 μg L⁻¹) was 100-fold bioconcentrated within four days. A decrease of the bioconcentration factor was observed within one week for the highest test concentrations (3.12 and 6.24 μg L⁻¹) suggesting enhanced excretory processes. The immediate mRNA up-regulation of pi class glutathione S-transferase proved that phase II biotransformation processes were induced. Disturbance of fundamental cell functions was assumed since the aryl hydrocarbon receptor has been permanently down-regulated. mRNA up-regulation of P-glycoprotein, superoxide dismutase and metallothioneine suggested enhanced elimination processes and ongoing oxidative stress. mRNA up-regulation of heat shock protein 70 in mussels exposed to the two highest concentrations clearly indicated impacts on protein damage.     

Ammonia emissions from a broiler farm: spatial variability of airborne concentrations in the vicinity and impact on adjacent woodland

Agricultural NH₃ emissions affect air quality and influence the nitrogen cycle. In the subject study, NH₃ emissions from a broiler farm and the resulting atmospheric concentrations in the immediate vicinity during three growing cycles have been quantified. Additionally, vegetation along a transect in an adjacent woodland was analysed. The emissions were as high as 10 kg NH₃ h⁻¹ and the atmospheric concentrations ranged between 33 and 124 μg NH₃ m⁻³ per week in the immediate vicinity. Measurements of the atmospheric concentrations over 7 weeks showed a substantial decline of mean concentrations (based on a 3-week average) from ∼13 to <3 μg NH₃ m⁻³, at 45- and 415-m distance from the farm. Vegetation surveys showed that nitrophilous species flourished when they grew closest to the farm (their occurrence sank proportionately with distance). A clearly visible damage of pine trees was observed within 200 m of the farm; this illustrated the significant impact of NH₃ emissions from agricultural sources on the sensitive ecosystem.     

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in human liver and adipose tissue samples from Belgium

Levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in paired human adipose tissue and liver samples (n=25) from Belgium. Average concentrations and standard deviation of sum PBDEs (congeners 28, 47, 99, 100, 153, 154 and 183) were 5.3+/-3.0 (range 1.4-13.2) and 3.6+/-2.1 (range 1.0-10.0)ngg(-1) lipid weight (lw) in adipose tissue and liver, respectively. These concentrations were similar to reported PBDE data from Belgium and were at the lower end of the concentration range reported elsewhere in the world. In both tissues under study, BDE 153 and BDE 47 were the most abundant PBDE congeners, contributing approximately 35% and 25% to the total PBDE content. Average concentrations and range of PCBs (sum of 23 congeners) were 490 (range 70-1130) and 380 (range 90-1140)ngg(-1)lw in adipose tissue and liver, respectively. No correlation between age and concentrations of PBDEs could be found (r=0.04), while PCB concentrations correlated significantly with age (r=0.62, p<0.01, for the sum PCBs; r=0.64, p<0.01 for PCB 153 alone). Factors, such as exposure pathways (food, dust and air), rates of bioaccumulation, metabolism and elimination, influence the concentrations of PBDEs differently than those of PCBs in humans.     

Diffusive partitioning tracer test for the quantification of nonaqueous phase liquid (NAPL) in the vadose zone: Performance evaluation for heterogeneous NAPL distribution

A partitioning tracer test based on gas-phase diffusion in the vadose zone yields estimates of the residual nonaqueous phase liquid (NAPL) saturation. The present paper investigates this technique further by studying diffusive tracer breakthrough curves in the vadose zone for a heterogeneous NAPL distribution. Tracer experiments were performed in a lysimeter with a horizontal layer of artificial kerosene embedded in unsaturated sand. Tracer disappearance curves at the injection point and tracer breakthrough curves at some distance from the injection point were measured inside and outside of the NAPL layer. A numerical code was used to generate independent model predictions based on the physicochemical sand, NAPL, and tracer properties. The measured and modeled tracer breakthrough curves were in good agreement confirming the validity of important modeling assumptions such as negligible sorption of chlorofluorocarbon (CFC) tracers to the uncontaminated sand and their fast reversible partitioning between the soil air and the NAPL phase. Subsequently, the model was used to investigate different configurations of NAPL contamination. The experimental and model results show that the tracer disappearance curves of a single-well diffusive partitioning tracer test (DPTT) are dominated by the near-field presence of NAPL around the tip of the soil gas probe. In contrast, breakthrough curves of inter-well tracer tests reflect the NAPL saturation in between the probes, although there is no unique interpretation of the tracer signals if the NAPL distribution is heterogeneous. Numerical modeling is useful for the planning of a DPTT application. Simulations suggest that several cubic meters of soil can be investigated with a single inter-well partitioning tracer test of 24-hour duration by placing the injection point in the center of the investigated soil volume and probes at up to 1 m distance for the monitoring of gaseous tracers.     

Water quality indices across Europe--a comparison of the good ecological status of five river basins

The European Water Framework Directive (WFD) requires the definition of near-natural reference conditions to determine the extent of water bodies' deviation from "good ecological status" caused by stress gradients. However, the classification of ecological quality depends on the assessment method applied and the stressor concerned. While assessment methods that are generally applicable would be favourable, many European countries employ the locally developed water quality metrics that assess the impact of organic pollution (including eutrophication) and the associated decrease in dissolved oxygen. These indices do not specifically address stress from organic toxicants, such as pesticides. The aim of this study was to examine the performance of presently used assessment methods to identify reference conditions of non-contaminated streams in five selected European river basins, covering the geographical region from Spain to Finland, as a crucial prerequisite to indicate toxic gradients. The analysis comprised the Belgium biotic index (BBI), the biological monitoring working party (BMWP) scoring system and the revised German saprobic index. For comparison, we included an adaptation of the recently developed SPEAR index. In two previous field studies, this metric highly correlated with measured pesticide gradients. In this study, SPEAR was the only indicator that was generally applicable to all monitoring data and capable of determining "high ecological status" of reference conditions in all basins. Thus, based upon previous and own results, the authors suggest the species at risk (SPEAR) index to be potentially useful as a European-wide index to address deviations from "good ecological status" due to organic toxicants and recommend it for consideration in integrated water-resource evaluations under the WFD.     

Post-combustion syntheses of PCDD/F and PBDD/F from halogen-rich fuel is suppressed by a pebble heater technology

GOAL, SCOPE AND BACKGROUND: Changes in German and European legislation shifted processing of polymer-rich shredding residues (SR) from landfill to thermal treatment. However, when waste of electric and electronic equipment (WEEE) is the source of SR, thermal treatment is complicated by halogens as well as the presence of polybrominated dioxins and furans (PBDD/F) and brominated flame retardants (BFR). Hence, WEEE requires high temperature incineration with sufficient residence times. Post-combustion synthesis of polyhalogenated dioxins and furans (PXDD/F) is dominant in the temperature range between 250-450 degrees C. Thus, a very rapid gas cooling from 450 degrees to 250 degrees C is important for proper raw gas treatment. The pebble heater technology developed by ATZ Entwicklungszentrum (Sulzbach-Rosenberg, Germany) might serve as an alternative to the state-of-the-art quench cooling. It is based on the application of a pebble bed of natural bulk material, which the exhaust gases flows through radially. It provides an excellent heat transfer and a temperature gradient in the range of 1,500-2,000 K/m. The paper presents data of a pilot application of the pebble heater technology for the treatment of raw gas derived from the incineration of polymeric materials from WEEE. METHODS: A liquid fuel was chosen in order to minimise technical modifications of the plant. It was analysed for halogens by x-ray fluorescence, for brominated flame retardants by HPLC-UV/MS and for PXDD/F by GC-HRMS. Combustion gases were rapidly cooled down to temperatures below 200 degrees C and emissions of PBDD/F and PCDD/ F were estimated without further off-gas treatment. PBDD/F emissions were computed as PCDD/F toxicity equivalents applying two different calculation approaches. RESULTS AND DISCUSSION: PCDD/F emissions accounted for 0.04 ng I-TEQ/Nm3 and are in compliance with European emission limits. Calculated PBDD/F toxicity equivalents exceeded the emission limit of 0.1 ng I-TEQ/Nm3 by factors of 75 and 208 depending on the calculation approach. A mass balance of PBDD/F and PCDD/F congeners revealed an efficient elimination of more than 95% in most cases. Lower reduction rates (76% for 2,3,7,8-TeBDF and 82% for 1,2,3,7,8-PeBDF) were attributed to incomplete combustion. An intended recovery of halogens by one-stage scrubbing downstream of the pebble heater was ineffective, recovering 28% of the applied chlorine and 9% of the bromine, only. CONCLUSIONS: Our pilot incineration test indicates that the pebble heater technology can effectively suppress a post-combustion synthesis of PCDD/F and PBDD/F, resulting in low PCDD/F emission levels without further off-gas treatment. The presented data state that WEEE is sensible to incomplete combustion, which will lead to increased PBDD/F emissions without increasing PCDD/F emission limits. This finding is especially relevant for small and low-technical incineration appliances, which have been reported to treat WEEE in developing countries and are considered to serve as a significant source of PXDD/F these days. RECOMMENDATIONS AND PERSPECTIVES: Monitoring of PCDD/F emissions only might considerably underestimate the total emission of dioxins and dioxin-like compounds. It is therefore an ineffective means for assessing resulting health risks, at least for those waste treatment plants which are considered to handle the increasing amounts of PBDD/ F-containing polymers from WEEE in future. Consequently, it is recommended to initiate a screening programme for PXDD/F emissions in large scale incineration facilities which are capable of treating WEEE shredder residues.     

Langfristigkeit ökosystemarer Forschung

Time in environmental science continues to be almost neglected. In connection with rising ecological problems long-term research, as is necessary for the evaluation and prediction of environmental conditions, seems to be an exception. Complex ecosystems, e.g. terrestrial and marine systems, however, are characterized by long lasting natural time-scales which must be taken into account by analyzing them. In this context the role of time in ecosystems research becomes important. Therefore, a data base was conceptualized that could take up the main characteristics of ecosystematic analyses. Annual research reports of ecosystem research centers were revised for taking them up into the data base. In this way it is possible to evaluate the pool of data on special aspects, especially on the time parameters of the analyses. One result — besides a partial unequality of the time scales in experiment and reality — is that long-term research in terrestrial ecosystems is very rare. The reasons for this are various, but cannot divert from the need for a greater consideration of longterm observation of the ecosystems. Otherwise the ecosystematic research will not be able to meet their tasks of evaluation and prediction.     

A habitat‐based approach to predict impacts of marine protected areas on fishers

Although marine protected areas can simultaneously contribute to biodiversity conservation and fisheries management, the global network is biased toward particular ecosystem types because they have been established primarily in an ad hoc fashion. The optimization of trade‐offs between biodiversity benefits and socioeconomic values increases success of protected areas and minimizes enforcement costs in the long run, but it is often neglected in marine spatial planning (MSP). Although the acquisition of spatially explicit socioeconomic data is perceived as a costly or secondary step in MSP, it is critical to account for lost opportunities by people whose activities will be restricted, especially fishers. We developed an easily reproduced habitat‐based approach to estimate the spatial distribution of opportunity cost to fishers in data‐poor regions. We assumed the most accessible areas have higher economic and conservation values than less accessible areas and their designation as no‐take zones represents a loss of fishing opportunities. We estimated potential distribution of fishing resources from bathymetric ranges and benthic habitat distribution and the relative importance of the different resources for each port of total catches, revenues, and stakeholder perception. In our model, we combined different cost layers to produce a comprehensive cost layer so that we could evaluate of trade‐offs. Our approach directly supports conservation planning, can be applied generally, and is expected to facilitate stakeholder input and community acceptance of conservation.