A worldwide survey of polychlorinated dibenzo-p-dioxins, dibenzofurans, and related contaminants in butter

The main source of human exposure to persistent organic pollutants (POPs) is, in general, food. In this study, 64 butter samples from 37 countries were analyzed to assess the global contamination of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), hexachlorobenzene (HCB), and 2,2-bis (4-chlorophenyl)-1,1,1-trichloroethane (DDT) together with its major metabolites. The objectives of the study were to assess the presence of major organohalogen contaminants in butter, to trace geographical differences, and to determine toxic equivalents (TEQs) of PCDDs/Fs and dioxin-like PCBs in butter. The highest PCDD/F concentrations were found in butter from Korea with an average of 1.4 pg TEQ g(-1) lipid weight (l.w.). from PCDD/F and an additional contribution from the non- and mono-ortho-PCBs of 0.55 pg TEQ g(-1) l.w. Belgian butter showed average levels of 0.53 and 1.2 pg TEQ g(-1) l.w. for PCDDs/Fs and PCBs, respectively, but one sample of Belgium butter had a total TEQ level as high as 4.0 pg TEQ g(-1) l.w. Three out of five butter samples from Portugal showed similarly high PCDD/F TEQ levels. The sigmaPCB levels in European butter appeared to be somewhat higher than in the samples from the rest of the world. The average contribution of CB-153 to the total PCB concentration was 22% (SD 6.4, coefficient of variation 29%). Generally, the PCBs contributed around 60% of the total TEQ value, with CB-126 contributing approximately half of this value. This shows the important TEQ contribution from dioxinlike PCBs to the total TEQs. The highest HCB levels were found in butter samples from Russia, Ukraine, Belgium, and Slovenia. Low levels of HCB in butter were generally found in the Southern Hemisphere. Butter samples from countries from Eastern Europe had elevated sigmaDDT concentrations, with a particularly high concentration in Ukraine butter, followed by some Russian samples, Brazil, and the U.S.     

Airborne PCB as a contamination risk on freeze-drying of sediment

In a study of polychlorinated biphenyls (PCB) in freeze-dried sediments from Swedish lakes, the samples were found to contain unexpectedly high concentrations of PCBs. In one of the lakes (Bj?rken), e.g. the concentration of PCB-28 was found to be 189 ng/g dw after freeze-drying compared to 7 ng/g dw after air-drying of the sediment and therefore our hypothesis was that the contamination had occurred during the freeze-drying procedure. Hence, a dry reference sediment (RS) was used in order to identify potential sources of PCB contamination. The investigation included freeze-drying of the dry RS in five different laboratories, exposure to the air in the freeze-drying room, storage at room temperature and air-drying in a certain fume hood and in a laminar flow clean bench. The pattern and concentrations of PCBs detected in the exposed RS were strongly influenced by low chlorinated PCB congeners under all of these conditions with exception for air-drying in the fume hood. Storage in the laboratory air resulted in a slight elevation in the concentrations of low chlorinated PCB congeners, whereas higher concentrations of all PCB congeners were observed after freeze-drying. In all experiments the contamination appeared to be due to adsorption of PCB from the laboratory air. On the basis of these findings we recommend that reference material be subjected to the entire procedure, including sample preparation, in order to monitor contamination and that a procedure involving solvent extraction of wet sediment samples is used, whenever possible, instead of procedures involving dry samples.     

Derivation of soil values for the path ‘Soil-Soil Organisms’ for metals and selected organic compounds using species sensitivity distributions

BACKGROUND, AIMS AND SCOPE: According to the German Federal Soil Protection Act, the natural function of soil as a habitat for human beings, animals, plants and soil organisms is, among other things, to be protected by deriving soil values for important chemicals regarding their amounts in the environment, their persistence and/or their toxicity. This contribution presents the results of the mathematical derivation of such values for nine metals and ten organic substances from soil ecotoxicological effect values available in the literature for microbial processes, plants and soil invertebrates. MATERIAL AND METHODS: Ecotoxicological data were mostly extracted from published papers and reports and had to originate from valid studies that were performed according to internationally standardised guidelines (e.g. ISO) or were otherwise well documented, plausible and performed according to accepted laboratory practice. As test results, both structural (i.e., effects on mortality, growth or reproduction) and functional (i.e., effects on microbial activity or organic matter breakdown) parameters were included. The derivation of soil values was performed using the distribution based extrapolation model (DIBAEX) and EC(50)s (Effective Concentration) as input data. RESULTS: For 19 compounds, soil values could be calculated. In 18 of these 19 cases clear laboratory ecotoxicological effects (i.e., EC50 values) below the calculated soil value have been found in the literature. DISCUSSION: In those few cases where a comparison with field studies is possible, effects have been observed in the same order of magnitude as the calculated soil values. A comparison with other similar approaches confirmed the plausibility of the calculated values. CONCLUSIONS: The DIBAEX-method is a feasible and widely accepted method for deriving soil values from ecotoxicological input data. Data availability was already satisfactory for some substances, but other substances, especially organics, were only poorly covered. The soil values presented here were based on EC50 input data. However, depending on the protection level aimed at by using soil values in legislation, it might be appropriate to use other input data such as NOECs in the derivation process. RECOMMENDATIONS AND PERSPECTIVES: It is recommended to generate an appropriate number of data for further relevant substances by means of a test battery or multi-species approaches such as terrestrial model ecosystems. These tests should also consider the influence of the bioavailability of substances. A final recommendation for legally binding soil values demands a plausibility check of the mathematically derived values. This should include a comparison with natural background concentrations, soil values for other pathways and soil values used in legislation of other countries. Finally, expert judgement always has to be considered.     

A simple procedure for correcting loading effects of aethalometer data

A simple method for correcting for the loading effects of aethalometer data is presented. The formula BC(CORRECTED) = (1 + k x ATN) x BC(NONCORRECTED), where ATN is the attenuation and BC is black carbon, was used for correcting aethalometer data obtained from measurements at three different sites: a subway station in Helsinki, an urban background measurement station in Helsinki, and a rural station in Hyyti?l? in central Finland. The BC data were compared with simultaneously measured aerosol volume concentrations (V). After the correction algorithm, the BC-to-V ratio remained relatively stable between consequent filter spots, which can be regarded as indirect evidence that the correction algorithm works. The k value calculated from the outdoor sites had a clear seasonal cycle that could be explained by darker aerosol in winter than in summer. When the contribution of BC to the total aerosol volume was high, the k factor was high and vice versa. In winter, the k values at all wavelengths were very close to that obtained from the subway station data. In summer, the k value was wavelength dependent and often negative. When the k value is negative, the noncorrected BC concentrations overestimated the true concentrations.     

Chemisch-analytische Charakterisierung technischen tierischen Fettes aus einer Tierkörperbeseitigungsanstalt

Aims and Scope

German rendering plants produce 300,000 tons of animal fat per year. Until recently, these raw products have been in wide use as nutritional additive for cattle and other animals fodder but now they have been banned due to their assumed role in BSE infection. Therefore, alternative fields of usage are required. In this context the Deutsche Bundesstiftung Umwelt (DBU) is sponsoring a joint research project which deals with the production and testing of cooling lubricants based on animal fat esters.

Methods

In a first step, characteristics and quality of the animal fat were analyzed and monitored for a whole year in order to identify e.g. seasonal variations. The investigations covered the following fat specific and trace analytical parameters: total contamination, sulfates ash, water content, peroxide number, iodine value, kinematical viscosity, neutralisation number (free fatty acids), fatty acid spectra, elements / heavy metals (Al, B, Ca, Cd, Cr, Cu, Fe, K, Mo, Mn, Na, Ni, P, Pb, S, Sn, V, W and Zn), polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans.

Results

Valuable hints on the design of the technical process of fatty acid methylesters production were gained by regarding the fat specific parameters. For example, filtration and dewatering of the fats proved necessary. Small variations of iodine value, viscosity and fatty acid spectrum pointed at a quite constant composition of the raw material in the course of the year. Clues to the degree of hydrolysis and decay of the fat were given by the share of free fatty acids. The saturated fatty acids, most interesting for the production of the cooling lubricants, were present in the fatty acid spectra in the rage of 36.4% to 54.6%. Trace analytical investigations concerning inorganic and organic pollutants proved a low basic contamination of the technical animal fats.

Outlook

Next step will be to present the pilot plant for the production of the cooling lubricants and further analytical results in context with the production process.     

A new approach to estimation of methane emission rates from landfills

Methane emission monitoring has become increasingly essential for diffusive area sources, especially for landfills, which contribute to a significant fraction of the total anthropogenic methane emission globally. Statutorily, methane emission rate from landfills in Germany shall be examined on a semiannual basis; however, an appropriate approach has yet to be developed and adopted for general use. In this study, a new method is proposed based on experimental results, which utilizes a TDLAS (Tunable Diode Laser Absorption Spectroscopy) instrument – GasFinder2.0® system and a dispersion model LASAT (Lagrangian Simulation of Aerosol Transport) as the measurement device and calculation model, respectively. Between April 2010 and December 2011, a research project was conducted at a pilot scale landfill in the south of Germany. Drawing on the extensive research into this pilot project, an effective strategy of measurement setup was determined. Methane concentration was measured with GasFinder2.0® system in the upstream and downstream sections of the project site, while wind and turbulence data were measured simultaneously by an ultrasonic anemometer. The average methane emission rate from the source can be calculated by using the results as input data in the dispersion model. With this method, site-specific measurement approaches can be designed for not only landfills, but also different diffusive area sources with less workload and lower cost compared to conventional FID (Flame Ionization Detector) method.     

The value of composting in Germany – Economy,ecology, and legislation

Based on a recent survey of German composting plants an evaluation of costs and benefits of composting was attempted. In this regard, several economical, ecological and legal aspects and some interrelations are discussed in this paper. A special emphasis is placed on the fees and compost prices of composting plants. It is also shown how the legal framework provides the economic basis for composting in Germany, how economical and ecological costs and benefits could be assessed, and why it is so difficult to determine the value of composting.     

Temporal limitations in the use of potassium dichromate as a blood preservative for the analysis of organohalogenated contaminants including polybrominated diphenyl ethers,dioxins and PCBs

Previous studies described the use of potassium dichromate (K₂Cr₂O₇) to successfully preserve whole blood for up to 34 days at room temperature (20–22°C) for analysis of chlorinated dioxins, dibenzofurans and PCBs. Potassium dichromate has been successfully employed as a preservative for cows’ milk and in a World Health Organization study of human milk. The use of two 100?mg tablets in 40 to 100?mL of whole blood in anticoagulant was found to provide almost identical levels of dioxins, dibenzofurans, PCBs and lipids as found in frozen comparison blood at??70°C which is generally regarded as the gold standard for blood preservation. Potassium dichromate was found to be preferable to 20 and 40% ethyl alcohol for this preservation. This finding opens opportunities for preservation under field conditions in developing countries where neither electricity nor dry ice is available. Not having to use dry ice for shipping also allows more flexibility in the choice of commercial carriers for transporting blood to an analytical laboratory. It is recommended considering a number of compounds in addition to those studied in our first report and extending the time beyond 34 days in order to determine if longer storage might also be feasible. Data on polybrominated diphenyl ethers (PBDEs), as well as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and selected polychlorinated biphenyls (PCBs) are reported. For the present study 3 and 6 months were chosen in potassium dichromate at room temperature compared to freezing at ?70°C. Data indicate that these times exceed the limits of efficacy of potassium dichromate for whole blood preservation. This was attributed to degradation of the lipid component of the blood. Since dioxins and closely related structural analogues are traditionally reported as lipid normalized blood levels, this degradation of lipids provides erroneous results. Therefore, potassium dichromate is not recommended for long-term storage beyond 34 days at room temperature. It is planned to study the time period between one and three months and higher temperature preservation for shorter time periods, simulating conditions in tropical countries, to attempt to extend further the ease and convenience of chemical preservation of blood.     

Partitioning of polybrominated diphenyl ether (PBDE) congeners in human blood and milk

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants (BFRs) which have recently been detected in human blood and milk in the USA, and presently these PBDE levels are found to be the highest globally. On a population basis, individual blood and individual milk analyses show similar congener patterns and levels. Until now, there has not been a study comparing PBDE levels in milk and blood of the same individuals. This study is the first to report these levels for PBDEs, though partitioning between blood and milk has been done previously for dioxins and polychlorinated biphenyls (PCBs). Twelve congeners in 11 nursing mothers’ blood and milk were found and the data describe partitioning ratios between blood and milk. The data suggest it may be easier for smaller, less brominated congeners to move from blood to milk.     

Bioavailability and metabolism of hexavalent chromium compounds †

Intratracheal instillation of ⁵¹CrCl₃ in anaesthetized rabbits resulted in partial absorption. In blood, the absorbed material was entirely confined to the plasma compartment. Only trace amounts were deposited in liver and kidney. By contrast, after similar application of Na, ⁵¹CrO₄ the bulk of blood radioactivity was present in red blood cells (RBC). Substantial deposition occurred in liver and kidneys. It is concluded that Cr(VI) may enter the body unreduced via the lung and is partially deposited in cells over a prolonged period of time.

Since chromium was accumulated in liver after administration of Cr(VI) we investigated the intracellular disposition of Cr(VI) in the isolated perfused liver. No significant sex differences in chromium distribution were observed. At the end of the experiments (1 h), 60% of the applied dose (312μg Cr/liver) was located in the cytosol, whilst 14% was in the mitochondria, 9% in the microsomal pellet and 2% was associated with the nuclei. Gel chromatography of the cytosolic compartment showed that the overwhelming part of chromium was eluted in fractions with an apparent molecular weight of 6,000 dalton. These fractions exhibited absorption maxima at 410nm and 548nm. It is concluded, that cytosolic reduction might be the main intracellular redox pathway for chromates. This view was confirmed by monitoring the reaction of Cr(VI) with GSH in vitro. GSH reduced Cr(VI) without further cofactors under formation of GSH‐chromium complexes, which possibly represent major intermediates in the metabolism of Cr(VI).