SETAC GLB — Gründung und Entwicklung

Goal, Scope, and Background

In the context of the ISO-standardisation of the in vitro micronucleus test for (waste) water testing (ISO/DIS 21427-2), a national collaborative study was organized by the German Federal Institute of Hydrology (BfG) involving ten laboratories of private companies, universities and public authorities. The formation of micronuclei (MN) is a special kind of chromosomal aberration. To meet the standardisation requirements for this method, encoded waste water samples, some of them spiked with known genotoxins, had to be tested in a collaborative study. The study should demonstrate practicability of the in vitro micronucleus test for waste water testing and should provide validity data.

Material and Methods

The micronucleus assay was performed with the permanently growing Chinese hamster lung fibroblast cell line V79. Four encoded samples from one municipal and one industrial wastewater treatment plant were tested with and without metabolic activation by S9-mix. Two of these samples were spiked in advance with defined concentrations of the clastogenic substances cyclophosphamide and mytomycin C. The defined assessment criterion for genotoxicity was the lowest dilution of a sample that does not show any significant induction of micronuclei (LID; lowest ineffective dilution). Cytotoxicity was judged by determining the survival-index, i.e. the percentage growth rate of the cells compared with the respective negative controls. As supplementary qualitative criteria, the mitotic index and the proliferation index were assessed.

Results

Although some of the laboratories had little or even no experience with the protocol of the in vitro micronucleus test described in the ISO-draft, all participants suceeded in establishing the assay within few weeks and in generating viable test results. The two nongenotoxic samples were detected as negative by 90% or 100% of the participants. The mitomycin C-spiked sample (expected to be positive without S9 supplementation) was correctly evaluated as positive by all laboratories. The cyclophosphamide-spiked sample (expected to be positive with S9 supplementation) was evaluated correctly as genotoxic by 80% of the laboratories. A post-test analysis found evidence that the false-negative results were due to technical failure, but not of a methodological nature. The sample LID values varied by no more than one dilution step around the median LID-value for all samples investigated. The survival index was proven to be a robust measure for estimation of cytotoxicity.

Discussion

The measurement of micronuclei is an important parameter for the detection of cytogenetic damage. In contrast to the single-cell gel electrophoresis assay (Comet assay), which is used as an indicator test, the in vitro micronucleus test detects non-repairable and thus manifested genetic damage. Consequently, the in vitro micronucleus test can be regarded as the more significant test system. A more frequent occurrence of micronuclei in treated cells suggests a risk of severe genetic damage for subsequent cell generations. In the interest of a precautionary environmental protection and health protection no municipal or industrial waste-water samples should show any significant induction of micronuclei in the treated cell populations.

Perspectives

The presented collaborative study was the first interlaboratory comparison of the in vitro micronucleus test using wastewater samples. The test system is intended to complement the already DIN- and ISO-standardised bacterial tests, i.e. the umu-test and the Ames plate incorporation assay. The data generated in the course of this project justify the transformation of the draft standard into the final draft international standard (FDIS), the preliminary stage of an international norm, so that a valid, standardised test system for the detection of cukaryotic genotoxicity in water samples might become available.     

Sources of anthropogenic platinum-group elements (PGE): Automotive catalysts versus pge-processing industries

Soil samples from the area of Hanau (Hessen, Germany) were analyzed for anthropogenic platinum-group elements (PGE). The results confirm the existence of two different sources for anthropogenic PGE: 1. automotive catalysts, and 2. PGE-processing plants. Both sources emit qualitatively and quantitatively different PGE spectra and PGE interelemental ratios (especially the Pt/Rh ratio). Elevated PGE values which are due to automotive catalysts are restricted to a narrow-range along roadside soil, whereas those due to PGE-processing plants display a large-area dispersion. The emitted PGE-containing particles in the case of automotive catalysts are subject to transport by wind and water, whereas those from PGE-processing plants are preferably transported by wind. This points to a different aerodynamic particle size. Pt, Pd, and Rh concentrations along motorways are dependent on the amount of traffic and the driving characteristics.     

Exposure to inhalable dust and endotoxin among Danish livestock farmers: results from the SUS cohort study

Studies on personal dust and endotoxin concentrations among animal farmers have been either small or limited to a few sectors in their investigations. The present study aimed to provide comparable information on the levels and variability of exposure to personal dust and endotoxin in different types of animal farmers. 507 personal inhalable dust samples were collected from 327 farmers employed in 54 pig, 26 dairy, 3 poultry, and 3 mink farms in Denmark. Measurements in pig and dairy farmers were full-shift and performed during summer and winter, while poultry and mink farmers were monitored during 4 well-defined production stages. The collected samples were measured for dust gravimetrically and analyzed for endotoxin by the Limulus amebocyte lysate assay. Simple statistics and random-effect analysis were used to describe the levels and the variability in measured dust and endotoxin exposure concentrations. Measured inhalable dust levels had an overall geometric mean of 2.5 mg m(-3) (range 相似文献   

Exposure to rubber process dust and fume since 1970s in the United Kingdom; influence of origin of measurement data

The objective of this study was to compare measured concentrations of rubber process dust and rubber fume originating from different sources in the British rubber manufacturing industry. Almost 8000 exposure measurements were obtained from industry-based survey results collected by the British Rubber Manufacturers' Association (BRMA), and covering the years 1977 to 2002, and from a series of small surveys contained in the Health and Safety Executive's (HSE) National Exposure Database (HSE-NEDB) from 1980 to 2002. The analysis investigated temporal trends in the exposure concentrations and the underlying main factors responsible for these changes. Analyses were carried out using hierarchical linear mixed effects models. Average personal exposures to rubber process dust and rubber fumes were respectively a factor 2 and 4 higher for the HSE-NEDB data when compared to data originating from the industry (BRMA data). Personal exposure to rubber process dust decreased on average by 4.1% (95% CI 4.7-3.6) annually for the BRMA data and slightly less at 2.3% (95% CI 5.2-0.7%) per annum for the HSE-NEDB data. Personal exposure to rubber fume also showed a downward temporal trend of 2.9% (95% CI 3.6-2.3%) and 4.8% (95% CI 7.4-2.1%) annually for the BRMA and HSE-NEDB data, respectively. These trends differed considerably between departments. No major changes in the estimated temporal trends in exposure concentrations were observed after including the presence of local exhaust ventilation in the models for any department in the BRMA and HSE-NEDB datasets. Lack of information on the quality and status of the local exhaust ventilation is the most likely explanation for this. In conclusion, even though there were relatively similar downward time trends in both rubber process dust and fume concentrations in both datasets, the source of exposure data was an important determinant of average exposure concentrations present in the British rubber manufacturing industry. Lack of detailed auxiliary information on company size, reason for sampling, measurement strategy and other potentially important determinants of exposure prevented an explanation for the observed differences in exposure level.     

Application of the UAM-V and Use of Indicator Species to Assess Control Strategies for Ozone Reduction in the Lower Fraser Valley of British Columbia

Modelled and measured indicator species ratios of O₃/NOz, O₃/NOy, H₂O₂/HNO₃, HCNO/NOy for the Lower Fraser Valley were compared with VOC-NO_x-O₃ sensitivity threshold values reported in previous studies. Modelled region - specific indicator ratio thresholds derived from 50% NOx and 50% VOC reduction scenarios are provided. They show strongest agreement with the H₂O₂/HNO₃ ratio values found elsewhere. A clear transition region for the LFV from VOC to NOx sensitivity could not be identified, but there is evidence that O₃ concentrations in the western valley, dominated by metropolitan Vancouver, are VOC sensitive, and the more rural eastern valley O₃ concentrations exhibit greater NO_x sensitivity. The UAM-V Process Analysis utility was used to identify physical and chemical mechanisms which contributed to O₃ formation and destruction and indicate the key importance of entrainment from elevated layers generated by the highly complex meteorological conditions in determining near surface O₃ concentrations.     

Fiberboard plant emissions control using a silent discharge plasma

A silent discharge plasma reactor was constructed to test a potential industrial application for controlling volatile organic carbon emission from fiberboard manufacturing plants. The reactor consisted of a cylindrical single barrier dielectric barrier discharge cell connected to a high‐voltage ac power supply. Various concentrations of turpene in air were introduced into the reactor under dry and wet conditions. The destruction removal efficiencies (DRE) were monitored using a gas chromatograph mass spectrometer (GCMS) and the concentrations of carbon dioxide generated from the oxidation ofturpene were monitored using a Fourier Transform Infrared Spectrometer (FTIR). It was found that 90 percent of the turpenes could be removed at modest energy densities and that adding water to the gas mix greatly enhanced the destruction of the turpenes. However, even at high energy densities, the oxidation of turpenes did not completely form carbon dioxide. The results suggest that the Silent Discharge Plasma (SDP) system can be used to control the emission of volatile organic compounds (VOCs) from fiberboard plants, but that further testing is needed to limit the emission of carbon monoxide.     

Generation and analysis of mixed chlorinated/brominated homologs of the halogenated natural product heptachloro-1'-methyl-1,2'-bipyrrole

The 2,3,3′,4,4′,5,5′-heptachloro-1′-methyl-1,2′-bipyrrole (Q1, MBP-79) and further halogenated 1′-methyl-1,2′-bipyrroles (MBPs) are a class of marine natural products repeatedly detected in seafood and marine mammals from all over the world. Only Q1 is currently commercially available as reference standard and the full synthesis of mixed brominated-chlorinated compound is rather complicated. For this reason, synthetic Q1 (240 mg) was transferred into bromine-containing MBPs by UV-irradiation in the presence of bromine. Bromine, which rapidly vanished from the solutions, was re-newed during the reaction in order to generate higher amounts of Br-containing MBPs. A total of ∼150 mg Q1 was transferred after ∼10 min irradiation with high amounts of Br₂ to give 30.5 mg BrCl₆-MBPs along with lower proportions of Br₂Cl₅-, Br₃Cl₄-, Br₄Cl₃- and traces of Br₅Cl₂-MBPs. Longer UV-irradiation in the presence of Br₂ even allowed for the detection of Br₆Cl-MBPs and traces of Br₇-MBP. However, this reaction also provided some unknown by-products. A sample stored in the dark and later in in-door light (no UV irradiation) also eliminated Q1 after 76 d in favour of heptahalogenated MBPs with up to three bromine substituents. The irradiation products were separated on silica, and fractions containing only Q1 and BrCl₆-MBPs were then further fractionated by non-aqueous RP-HPLC. A pure isolate of the major BrCl₆-MBP (∼1.5 mg) was characterized by GC/MS and ¹³C NMR to be 2-bromo-3,3′,4,4′,5,5′-hexachloro-1-methyl-1,2′-bipyrrole (Br-MBP-75). Partial GC enantioseparation of the axially chiral Br-MBP-75 was achieved on a β-PMCD column. A full enantioseparation was managed by enantioselective HPLC using a NUCLEOCEL DELTA S column. Low amounts of pure BrCl₆-MBP enantiomers could be trapped.