Rapid changes in profiles from stored materials used in scent training of explosive detection dogs.

Canines trained on scents from materials emitting vapours of explosives and related compounds are widely used to detect explosives in civilian, military and forensic applications. Despite the importance of these training materials, there is limited knowledge on how long these subsamples can be stored and whether vapour profiles change over time. We developed a sampling methodology that makes use of a secondary chamber for stabilisation of headspace concentration to allow reliable and reproducible determination of scent profiles. The effect of aging was investigated by following the response of volatile markers emitted from eight common explosives in open and closed containers over two months or two years. The initial headspace air volume consisted of a wide variety of chemical substances related to explosives, with levels varying in magnitude from low ppb to ppm. All included subsamples were affected by aging by demonstrating exponentially lower levels, and five subsamples showed a significant change in their scent profile. The dominant components decreased on a short time scale for plastic explosives based on RDX, PETN and dynamite as well as for granules of octol and ammonium nitrate mixed with fuel. For flakes of TNT, granules of Comp B and nitrocellulose powder, headspace air concentrations declined, but the overall character of their profiles were in general more stable. The overall changes, i.e., lower levels and/or changed profiles, justifies regular checks of the scent status of training materials. Considering these results together with data displaying marginal changes in energetic performance, it is advisable to complement scent training with training materials subjected to different durations of aging.

Choosing the number of images and image position when analyzing the UNC Passive Aerosol Sampler for occupational exposure assessment.

The University of North Carolina passive aerosol sampler (UNC sampler) could be an alternative when measuring occupational dust exposure, but the time required for microscopic imaging of the sampler needs to be reduced to make it more attractive. The aims of this study were to (1) characterize the effect on precision when reducing imaging, in order to shorten analysis time and (2) assess if the position of the images makes a difference. Eighty-eight samplers were deployed in different locations of an open pit mine. Sixty images were captured for each UNC sampler, covering 51% of its collection surface, using scanning electron microscopy. Bootstrapped samples were generated with different image combinations, to assess the within-sampler coefficient of variation (CVws) for different numbers of images. In addition, the particle concentration relative to the distance from the center of the sampler was studied. Reducing the number of images collected from the UNC sampler led to up to 8.3% CVws for 10 images when calculating respirable fraction. As the overall CV has previously been assessed to 36%, the additional contribution becomes minimal, increasing the overall CV to 37%. The mean concentrations of the images were modestly related to distance from the center of the sampler. The CVws changed from 8.26% to 8.13% for 10 images when applying rules for the image collection based on distance. Thus, the benefit of these rules on the precision is small and the images can therefore be chosen at random. In conclusion, reducing the number of images analyzed from 60 to 10, corresponding to a reduction of the imaged sampling area from 51% to 8.5%, results in a negligible loss in precision for respirable fraction dust measurements in occupational environments.

Emission factors for gases and particle-bound substances produced by firing lead-free small-caliber ammunition.

Lead-free ammunition is becoming increasingly popular because of the environmental and human health issues associated with the use of leaded ammunition. However, there is a lack of data on the emissions produced by firing such ammunition. We report emission factors for toxic gases and particle-bound compounds produced by firing lead-free ammunition in a test chamber. Carbon monoxide, ammonia, and hydrogen cyanide levels within the chamber were analysed by Fourier transform infrared spectroscopy, while total suspended particles and respirable particles were determined gravimetrically. The metal content of the particulate emissions was determined and the associated organic compounds were characterized in detail using a method based on thermal desorption coupled to gas chromatography and mass spectrometry. The particulate matter (∼30 mg/round) consisted primarily of metals such as Cu, Zn, and Fe along with soot arising from incomplete combustion. Nitrogen-containing heterocyclic aromatic compounds such as carbazole, quinolone, and phenazine were responsible for some of the 25 most significant chromatographic peaks, together with PAHs, diphenylamine, and phthalates. Emission factors were determined for PAHs and oxygenated PAHs; the latter were less abundant in the gun smoke particles than in domestic dust and diesel combustion smoke. This may be due to the oxygen-deficient conditions that occur when the gun is fired. By using an electrical low pressure impactor, it was demonstrated that more than 90% of the particles produced immediately after firing the weapon had diameters of less than 30 nm, and so most of the gun smoke particles belonged to the nanoparticle regime.

Pressurized liquid extraction with water as a tool for chemical and toxicological screening of soil samples at army live-fire training ranges.

Significant discrepancies in the results of risk assessments based on chemical and toxicity analyses of soils may arise through differences in the efficiency of the extraction or leaching methods used. A rapid technique that may be used in the screening phase of live-fire training ranges and suitable for extracting explosive residues is pressurized liquid extraction (PLE) with water. Therefore, PLE and the commonly used batch leaching method EN-124 57-2 were compared for their utility to extract specific residues from soil samples collected from the Canadian Forces Base (CFB) Petawawa, Ontario. After extraction the cytotoxicity of the samples were assessed in the L-929 growth inhibition assay. The PLE method yielded extracts suitable for direct use in the toxicity assay within 20 min as compared to 24h for the batch leaching method. Analysis of the extracts showed that the PLE water extracts tended to give higher recoveries of explosive residues and the resulting exposure concentrations were confirmed by higher cytotoxicities. Furthermore, gas chromatography-mass spectrometry analyses showed that the samples contained significant amounts of several munition-related stabilizers and plasticizers of toxicological significance in addition to the analysed explosive residues. In conclusion, PLE using water is a promising extraction technique for both chemical and toxicological screening of soil samples from areas that may be contaminated with explosive residues.

Identification of markers for PCB exposure in plasma from Swedish construction workers removing old elastic sealants.

The objective of the present study was to identify PCB-indicators of occupational exposure related to the removal of old elastic sealants. Blood samples were collected from workers involved in removing elastic sealants. Samples were also taken from age- and sex-matched controls. A majority of the exposed workers were re-sampled after 10 months. All samples were analysed for 19 PCBs. The levels in the exposed workers were twice as high as those in the controls, 575 and 267 ng g(-1) lipid, respectively, but were essentially unchanged at the second sampling. The PCB patterns also differed. Levels of many less chlorinated PCBs were much higher in the exposed workers, compared to the controls, and principal component analysis (PCA) revealed that easily metabolized PCBs decreased in the exposed workers during the study. This finding indicates that elimination exceeded uptake during the study period, and that the safety information given to the workers had been effective. PCA was also used to identify exposure markers. The relatively persistent PCBs 56/60 and 66, the easily metabolized PCBs 44, 70 and 110 (with vicinal hydrogens in meta/para-positions) and the very persistent PCBs 153 and 180 were found to be good markers for occupational, recent occupational and background (dietary) exposure, respectively. A PCA model based on these markers was equally effective in differentiating between exposed individuals and controls, and between recent and less recent exposure, as a model based on all PCBs.

Sorbent-assisted liquid-liquid extraction (Chem-Elut) of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in the lipid fraction of human blood plasma.

This work compares two lipid extraction methods for determining 24 polychlorinated biphenyls (PCBs), seven dibenzo-p-dioxins (PCDDs) and ten dibenzofurans (PCDFs) in human blood plasma. The first method was based on conventional liquid-liquid partitioning with chloroform-methanol and the other made use of a sorbent (Chem-Elut) to facilitate the partitioning of lipids into a mixture of hexane and 2-propanol. A multi-layer-silica column including acid- and base-impregnated silica gel was used to reduce the amounts of lipid present in the samples before a basic alumina clean-up step and activated carbon fractionation of planar analytes (PCDD/Fs and non-ortho-PCBs) and non-planar analytes (including ortho-chlorinated PCBs). Gas chromatography coupled to high resolution mass spectrometry was used to identify and quantify the analytes in the two fractions. The wet weight based concentrations obtained by the two methods were in agreement but both methods suffer from large organic solvent consumption. The toxic equivalencies derived for PCBs and PCDD/Fs using the two methods were also in agreement. However, the chloroform-methanol method gave slightly higher lipid recoveries, although with greater variation, than the sorbent-assisted method. Nevertheless, despite giving lower lipid recoveries, the sorbent-assisted method has advantages in ease of use and applicability to whole blood samples. The formation of emulsions was avoided with the Chem-Elut method, which probably explains the lower variability in the lipid determinations.

Concentrations of organochlorines related to titers to Epstein-Barr virus early antigen IgG as risk factors for hairy cell leukemia.

Hairy cell leukemia (HCL) is a rare chronic B-cell malignancy that, according to modern classifications, is a subgroup of non-Hodgkin lymphomas (NHLs). A rapid increase in incidence of NHL has been reported in many countries. The reasons for this increase are largely unknown, but exposure to organochlorines has been suggested as a risk factor. Epstein-Barr virus is a human herpesvirus that has been associated with certain subgroups of NHL. In this study, we measured lipid adjusted blood concentrations (in nanogram per gram) of 36 congeners of polychlorinated biphenyls (PCBs), p, p'-dichlorodiphenyldichloroethylene (p,p'-DDE), hexachlorobenzene (HCB), and four subgroups of chlordanes (trans-nonachlor, cis-nonachlor, MC6, and oxychlordane) in incident cases of HCL and controls from the general population. We obtained results on organochlorines and antibodies for 54 cases and 54 controls. Titers of antibodies to the Epstein-Barr early antigen and Epstein-Barr nuclear antigen, measured as P107, were correlated to concentrations of organochlorines to evaluate the possibility of an interaction between these factors in the pathogenesis of HCL. We found no significant difference in lipid-adjusted blood concentrations of total PCBs, p,p'-DDE, HCB, or the sum of the chlordanes between cases and controls. Titers of antibodies to Epstein-Barr early antigen IgG [Greater and equal to] 40 were correlated to an increased risk for HCL. This risk was further increased in those with a level above the median value of p,p'-DDE, HCB, or the sum of the chlordanes, suggesting an interaction between Epstein-Barr virus and a higher concentration of these chemicals. We also found increased risk for the sum of immunotoxic PCB group.

Multivariate data evaluation of PCB and dioxin profiles in the general population in Sweden and Spain.

Thirty-three polychlorinated biphenyls and 20 dioxin-like congeners were determined by GC-MS in blood and adipose tissue samples from two general population groups, one in Spain (n = 35) and one in Sweden (n = 28). The results were evaluated by multivariate projection (Simca), after normalisation to the most abundant and stable congener in each data set, in order to reveal differences in the "national" congener profiles. The mean values of each population group did not differ significantly. The sum of PCBs in the Spanish was 1450 ng/g and in the Swedish 1310 ng/g. The sum of the dioxin-like compounds in Spain was 1180 pg/g and in Sweden 804 pg/g. The congener profiles differed between the countries. Mainly the higher chlorinated congeners for both the dioxin-like compounds and the PCBs are more dominant in the Spanish group compared to the Swedish.

Persistent health effects of dioxin contamination in herbicide production.

A total of 159 cases of chloracne reported in 1969-1975 in TCDD-contaminated production of the herbicide 2,4,5-T have been followed for mortality and morbidity up to 1996 when blood and urine tests were performed on 50 survivors of these exposed chemical workers and matched controls. In exposed, the most frequent cause of sick leave was chloracne which persisted in 32%. Neurological symptoms were reported frequently (44% sleep disturbance, 32% headache, 30% neuralgia). BSR, leucocytes, gamma-GT, SGOT, and SGPT were significantly higher in exposed than in controls. The effects of exposure (P= 0.002) and alcohol (P= 0.002) on gamma-GT were found to be independent of each other. Comparisons within the chloracne cohort showed significantly exposed TCDD per gram blood lipid in patients with a history of liver disease (mean 801 pg/g) than without (mean 407 pg/g). Other congeners were not found elevated but some higher chlorinated furans and PCBs were found reduced in patients with liver disease. In multiple regression analysis with the factors age, alcohol, and log TCDD, the effects of TCDD and its interaction with age were found significant, indicative of chronic liver damage after high TCDD exposure at a young age. The prevalence of neurological symptoms and signs of chronic liver disease were related to TCDD in blood and abnormal poryphyrins in urine. In 48% coproporphyrin I > III ratio was elevated, this group showing increased TCDD (mean 719 pg/g). These results contribute to the evidence that chloracne is not the only chronic disease which can be related to TCDD exposure, even 23 years after exposure and despite high intersubject variability of TCDD half-life and other exposures.

Polybrominated diphenyl ethers detected in human adipose tissue from Spain.

Polybrominated diphenyl ethers (PBDEs) were detected in 13 human adipose tissue samples from Spain, 3 women and 10 men. Tetra-, penta- and hexabrominated diphenyl ethers were determined at ng/g lipid (ppb) level in all the samples. The average TeBDE level was 1.36 ng/g, the average PeBDE was 0.93 ng/g and the HxBDE 1.83 ng/g. Human adipose tissue levels of PBDE obtained in the current samples from Spain are comparable with the tissue levels reported in recent Swedish investigations.

Dioxin and dibenzofuran concentrations in adipose tissue of a general population from Tarragona, Spain.

Polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels were determined in adipose tissue of 15 autopsied subjects who at the time of death had lived in the city of Tarragona (Catalonia, Spain) and surroundings during at least the last 10 years. PCDD/F concentrations ranged between 13.37 and 69.37 ng I-TEQ/kg fat, with mean and median values of 30.98 and 26.30 ng I-TEQ/kg fat, respectively. PCDD/F concentrations were higher (p < 0.01) in women (mean value: 44.95 ng I-TEQ/kg fat) than in men (mean value: 24.00 ng I-TEQ/kg fat). Although individuals living in industrial areas showed higher PCDD/F levels than those living Tarragona downtown the difference was not statistically significant. When Principal Component Analysis was applied to the concentrations of PCDD/Fs found in the 15 adipose tissue samples together with those found in 20 blood samples collected in a previous study, a single two-dimensional model was obtained, which would explain 62.9% of the variance in the data. The PCDD/F concentrations in adipose tissue found in the current study are of the same order of magnitude than those reported for most industrialized countries.

Dioxin and dibenzofuran concentrations in blood of a general population from Tarragona, Spain.

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in plasma samples of 20 nonoccupationally exposed subjects living in the vicinity of a new hazardous waste incinerator (HWI), now under construction in Tarragona (Catalonia, Spain). The mean PCDD/F value was 27.0 pg I-TEQ/g lipid with a range from 14.8 to 48.9 pg I-TEQ/g lipid. All samples showed higher PCDD than PCDF levels. Although PCDD/F concentrations were higher in women (27.7 pg I-TEQ/g lipid) than in men (25.2 pg I-TEQ/g lipid), the difference was not statistically significant. While a significant correlation (r = 0.565, p < 0.01) between the age of the subjects and the levels of PCDD/F in plasma could be observed, no significant differences were found in relation to the specific residential area. The plasma concentrations of PCDD/F obtained in the current study are discussed and compared with the results of similar investigations reported in the last two years.

Identification of 19 polybrominated diphenyl ethers (PBDEs) in long-finned pilot whale (Globicephala melas) from the Atlantic.

Nineteen tetra- to hexabrominated diphenyl ethers were identified at ppb concentration in the blubber of pilot whale caught off the coast of the Faroe Islands in 1994 and 1996. Higher total concentrations were found in the pooled samples of young males (3,160 ng/g lipid) and females (3,038 ng/g lipid) compared to adult females (843 ng/g and 1,048 ng/g lipid) and males (1,610 ng/g lipids). The predominant isomers in all samples were 2,2',4,4'-TeBDE (PBDE #47) and 2,2',4,4', 5-PeBDE (PBDE #99) accounting for some 70% of the sum of the 19 isomers.

[Do flame retardants increase the risk of non-Hodgkin lymphoma? The levels of polybrominated diphenyl ethers are increasing in the environment]. / Okar flamskyddsmedel risken för non-Hodgkin-lymfom? Halterna av polybromerade difenyletrar ökar i miljön.

Adipose tissue levels of tetra-BDE (2,2',4,4' tetra-brominated diphenyl ether) were measured in 42 male or female cancer patients [19 with non-Hodgkin's lymphoma (NHL), 23 with malignant melanoma (MM)], and in 27 controls without a diagnosis of cancer. As compared with tetra-BDE concentrations in controls, those in the MM subgroup did not differ, but those in the NHL subgroup were higher. Subgrouping of the cancer patients by occupational categories showed professional car, bus and truck drivers (at possible risk of exposure to PBDEs used as flame retardants in vehicle manufacture) to have higher tetra-BDE levels than controls, but not computer operators (at possible risk of exposure to PBDEs used in VDUs). Due to the small size of the series, however, the results may solely be regarded as hypothesis-generating, and further studies are needed.

Concentrations of the flame retardant 2,2',4,4'-tetrabrominated diphenyl ether in human adipose tissue in Swedish persons and the risk for non-Hodgkin's lymphoma.

Concentrations of the flame retardant 2,2',4,4'-tetrabrominated diphenyl ether (2,2',4,4'-TeBDE) in the adipose tissue of 77 individuals from Sweden were determined. The subjects were recruited during the time period 1995-97 and encompassed both men and women ranging from 28 to 85 years in age. Of the subjects included, 19 patients had non-Hodgkin's lymphoma (NHL), 23 patients had malignant melanoma, 8 patients had other cancers or in situ changes, and 27 persons had no cancer diagnosis. The mean concentration of 2,2',4,4'-TeBDE was 5.1 ng/g lipid (range 0.6-27.5) for the 27 persons without malignancies. For NHL patients the mean concentration was 13.0 ng/g lipid (range 1.0-98.2). A nonsignificantly elevated risk with dose response was found for NHL when the cases and controls were compared in the two highest concentration groups (2.05-< 5.43 ng/g lipid and > or = 5.43 ng/g lipid) with the lowest group (< 2.05 ng/g lipid) yielding odds ratio (OR) 1.9 with 95% confidence interval (CI) 0.3-14 and OR 3.8, CI 0.7-26, respectively. The results for the patients with malignant melanoma did not differ from the controls.