Incorporating availability/bioavailability in risk assessment and decision making of polluted sites, using Germany as an example.

Nearly all publications dealing with availability or bioavailability of soil pollutants start with the following statement: the determination of total pollutant content will lead to an over-estimation of risk. However, an assessment of contaminated sites should be based on the determination of mobile fractions of pollutants, and the fractions with potential for mobilisation that threaten groundwater and surface water, and the actual and potential fractions available for uptake by plants, soil microflora and soil organisms. After reviewing the literature for method proposals concerning the determination of available/bioavailable fractions of contaminants with respect to leaching, plants, microorganisms (biodegradation) and soil organisms, we propose a testing and assessment scheme for contaminated sites. The proposal includes (i) already accepted and used methods, (ii) methods which are under standardisation, and (iii) methods for which development has just started in order to promote urgently needed research.

Substance-related environmental monitoring strategies regarding soil, groundwater and surface water - an overview.

Substance-related monitoring is an essential tool within environmental risk assessment processes. The soundness of policy decisions including risk management measures is often directly related to the reliability of the environmental monitoring programs. In addition, monitoring programs are required for identifying new and less-investigated pollutants of concern in different environmental media. Scientifically sound and feasible monitoring concepts strongly depend on the aim of the study. The proper definition of questions to be answered is thus of pivotal importance. Decisions on sample handling, storage and the analysis of the samples are important steps for the elaboration of problem-oriented monitoring strategies. The same applies to the selection of the sampling sites as being representative for scenarios to be investigated. These steps may become critical to handle for larger international monitoring programs and thus trigger the quality of their results. This study based on the work of an IUPAC (International Union of Pure and Applied Chemistry) task group addresses different kinds and approaches of substance-related monitoring of different compartments of soil, groundwater and surface water, and discusses their advantages and limitations. Further important aspects are the monitoring across policies and the monitoring data management using information systems.

Applicability of non-exhaustive extraction procedures with Tenax and HPCD.

Chemical extraction techniques like non-exhaustive extraction with Tenax or hydroxypropyl-ß-cyclodextrin (HPCD) have been shown to measure the biodegradable fraction of aromatic contaminants like PAHs in soil. However, there is little research on the chemical prediction of aliphatic hydrocarbon degradation. The aim of this study was to investigate the potential for HPCD and Tenax extractions to predict PAH and petroleum hydrocarbon biodegradation in soil. 11 historically contaminated soils with PAH concentrations between 74 and 680 mg/kg and concentrations of petroleum hydrocarbons from 330 to 4,704 mg/kg were analysed. Both non-exhaustive extraction procedures showed promising results for estimating the available contaminant fraction of both contaminant groups concerning the feasibility, reproducibility and correlation with soil biodegradation applying single point testing. Both methods have the potential to be used to assess the biodegradable hydrophobic organic pollutant fraction in contaminated soils. In a direct comparison of the two extraction procedures, Tenax extraction is assessed to be more time-consuming than HPCD extraction. Furthermore, a sufficient soil/Tenax ratio has to be considered.

Safety evaluation for a biodiesel process using prion-contaminated animal fat as a source.

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 (PrP(Sc)). 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 (PrP(Sc)) 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.

Pesticide soil sorption parameters: theory, measurement, uses, limitations and reliability.

The soil sorption coefficient Kd and the soil organic carbon sorption coefficient KOC of pesticides are basic parameters used by environmental scientists and regulatory agencies worldwide in describing the environmental fate and behavior of pesticides. They are a measure of the strength of sorption of pesticides to soils and other geosorbent surfaces at the water/solid interface, and are thus directly related to both environmental mobility and persistence. KOC is regarded as a 'universal' parameter related to the hydrophobicity of the pesticide molecule, which applies to a given pesticide in all soils. This assumption is known to be inexact, but it is used in this way in modeling and estimating risk for pesticide leaching and runoff. In this report we examine the theory, uses, measurement or estimation, limitations and reliability of these parameters and provide some 'rules of thumb' for the use of these parameters in describing the behavior and fate of pesticides in the environment, especially in analysis by modeling.