Nematodentest

For the assessment of contaminated and remediated soils and substrates, and the estimation of chronic toxicity of soil contaminations, an ecotoxicological test was developed using the terrestrial nematodePanagrellus redivivus. The population dynamics expressed by the reproduction factor (VF) allows an estimation of soil quality within seven days. Due to the rapid generation time ofPanagrellus (< 5 d), the short test duration is considered to be sufficient. The suitability of this test duration is considered to be sufficient. The suitability of this test was evaluated by investigating soils which had been contaminated using applications of specific pollutants (lindane and PCB 52).     

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Biodegradation and speciation of residual SS-ethylenediaminedisuccinic acid (EDDS) in soil solution left after soil washing

This paper aims to investigate the degradation and speciation of EDDS-complexes (SS-ethylenediaminedisuccinic acid) in soil following soil washing. The changes in soil solution metal and EDDS concentrations were investigated for three polluted soils. EDDS was degraded after a lag phase of 7-11 days with a half-life of 4.18-5.60 days. No influence of EDDS-speciation on the reaction was observed. The decrease in EDDS resulted in a corresponding decrease in solubilized metals. Changes in EDDS speciation can be related to (1) initial composition of the soil, (2) temporarily anoxic conditions in the soil slurry after soil washing, (3) exchange of EDDS complexes with Cu even in soils without elevated Cu and (4) formation of NiEDDS. Dissolved organic matter is important for metal speciation at low EDDS concentrations. Our results show that even in polluted soils EDDS is degraded from a level of several hundred micromoles to below 1 microM within 50 days.     

Determination of chemical warfare agents

Chlorovinylannes (Lewisites) were produced and handled during WW I and WW II as chemical warfare agents. Residues of these cwa and their metabolites are still present today and continue to contaminate soil and water. A gas Chromatographic method for the detection and determination of chlorovinylarsines (Lewisites) and their metabolites is shown. Lewisite II and Lewisite III, but not Lewisite I and the metabolites of Lewisite I and Lewisite II can be detected and determined using GC/ECD. After derivatization with thiols, the sum of Lewisite I or Lewisite II and their metabolites are detected. With the proper selection of the thiol, matrix interferences can be eliminated because of the different retention times of the derivatives.     

Effect of different types of elemental sulfur on bioleaching of heavy metals from contaminated sediments

The application of two different types of elemental sulfur (S0) was studied to evaluate the efficiency on bioleaching of heavy metals from contaminated sediments. Bioleaching tests were performed in suspension and in the solid-bed with a heavy metal contaminated sediment using commercial sulfur powder (technical sulfur) or a microbially produced sulfur waste (biological sulfur) as substrate for the indigenous sulfur-oxidizing bacteria and thus as acid source. Generally, using biological sulfur during suspension leaching yielded in considerably better results than technical sulfur. The equilibrium in acidification, sulfur oxidation and metal solubilization was reached already after 10-14 d of leaching depending upon the amount of sulfur added. The metal removal after 28 d of leaching was higher when biological sulfur was used. The biological sulfur added was oxidized with high rate, and no residual S0 was detectable in the sediment samples after leaching. The observed effects are attributable to the hydrophilic properties of the biologically produced sulfur particles resulting in an increased bioavailability for the Acidithiobacilli. In column experiments only poor effects on the kinetics of the leaching parameters were observed replacing technical sulfur by biological sulfur, and the overall metal removal was almost the same for both types of S0. Therefore, under the conditions of solid-bed leaching the rate of sulfur oxidation and metal solubilization is more strongly affected by transport phenomena than by microbial conversion processes attributed to different physicochemical properties of the sulfur sources. The results indicate that the application of biological sulfur provides a suitable means for improving the efficiency of suspension leaching treatments by shortening the leaching time. Solid-bed leaching treatments may benefit from the reuse of biological sulfur by reducing the costs for material and operating.     

Impact of short-term and long-term elevated CO2 on emission of carbonyls from adult Quercus petraea and Carpinus betulus trees

The study aimed to elucidate the effect of elevated CO2 in short- and long-term experiments on the emission potential of carbonyls from mature oak (Quercus petraea) and hornbeam (Carpinus betulus). The trees were investigated using a canopy crane established in a mixed forest in Switzerland. Short-term CO2 experiments were performed on single leaves with a gas exchange measuring unit by increasing CO2 in the enclosure before and during the measurements. Long-term CO2 fumigation was performed for one vegetation period by a webFACE design. Short-term as well as long-term exposure of leaves resulted in no significant changes in carbonyl exchange in neither Q. petraea nor C. betulus. Carbonyl emission was not affected by stomatal closure under elevated CO2 levels. In contrast to the emission of isoprenoids from vegetation which is thought to be reduced at elevated atmospheric CO2, the exchange of carbonyls seems to be generally unaffected under these conditions.     

Safety Evaluation for a Biodiesel Process Using Prion-Contaminated Animal Fat as a Source (6 pp)

Background Due to the bovine spongiform encephalopathy (BSE), specified risk material (SRM) as well as animal meat and bone meal (MBM) are banned from the food and feed chain because of a possible infection with pathogenic prions (PrPSc). Nowadays, prions are widely accepted to be responsible for TSE(transmissible spongiform encephalopathies)-caused illnesses like BSE and scrapie, and especially for the occurrence of the new variant of CJD in humans. Presently, SRM and MBM are burnt under high temperatures to avoid any hazards for humans, animals or the environment. The aim of this study was to evaluate a method using animal fat separated from Category I material which includes SRM and the carcasses of TSE-infected animals, or animals suspected of being infected with TSE, as a source for producing biodiesel by transesterification, analogous to the biodiesel process using vegetable oil. Methods For this purpose, animal fat was spiked with scrapie-infected hamster brain equivalents – as representative for a TSE-infected animal – and the biodiesel manufacturing process was downscaled and performed under lab-scale conditions. Results and Discussion The results analysed by Western blotting showed clearly that almost each single step of the process leads to a significant reduction of the concentration of the pathogenic prion protein (PrPSc) in the main and side-products. Conclusion The data revealed that the biodiesel production, even from material with a high concentration of pathogenic prions, can be considered as safe. Recommendations and Outlook The obtained results indicated that biodiesel produced from prion-contaminated fat was safe under the tested process conditions. However, it has to be pointed out that the results cannot be generalized because a different process control using other conditions may lead to different results and then has to be analysed independently. It is clear that the production of biodiesel from high risk material represents a more economic usage than the combustion of such material.