Seasonal variations of PCDD/Fs congeners in air, soil and eggs from a Polish small-scale farm.

The transfer of dioxin from the environment to the food is a problem in a consumers' health protection. The study aimed to determine the concentration of dioxins in free-range chicken eggs, air and soil samples, collected during 12 months on an individual small farm, located in Malopolska region, Poland. In the majority of analyzed eggs, the concentrations of dioxin exceeded several times the legal limit of 2.5 pg WHO-TEQ g-1fat. Seasonal changes in the PCDD/Fs congeners in egg, air and soil samples were studied. During the winter season, when the combustion processes of the solid fuel in domestic furnaces are intensive, the PM10 concentration in the Malopolska region exceeds the legal limit (50µg/m3) even eight times. In this period, eggs, air and soil samples showed a higher share of PCDFs with a specific contribution of 2,3,7,8-TCDF. During the summer months, in the egg, air and soil samples, the share of PCDDs is higher with dominant OCDD and 1,2,3,4,6,7,8-HpCDDs, showing the effect of other combustion processes such as grass utilization or burning plastic wastes in controlled fires. In August, the month of the highest average air temperature and lowest rainfall amount, the highest toxicity of PCDD/Fs in eggs (9.52pgWHO-TEQ g-1fat) was found. Due to the similarity of the shares of PCDD/Fs congeners in total WHO-TEQ value we can take into account the influence of toxicity of PCDD/Fs in the air and soil on the toxicity in the eggs.

Cell-specific and dose-dependent effects of PAHs on proliferation, cell cycle, and apoptosis protein expression and hormone secretion by placental cell lines.

In the preset study we measured the concentrations of 16 priority PAHs in maternal blood and placental tissue by using the GC-MS/MS system, and investigated the effects of selected PAHs (naphthalene, anthracene, phenanthrene, pyrene) and mixtures on BeWo and JEG-3 human placental cell line proliferation (Alamar Blue), cytotoxicity (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (XTT), lactate dehydrogenase (LDH), acid phosphatase (AP), endocrine activity (progesterone and estradiol secretion) and apoptosis (cyclin A1, cyclin D2, cdk 2, cdk 4, Bcl-xl, Bax, and caspase-3 protein expression). The concentrations of 16 PAHs in maternal blood were higher than in placental tissue. In JEG-3 cells except for naphthalene, all PAHs studied and their mixtures at maternal doses, and only naphthalene at placental doses, increased XTT, while in BeWo cells, placental doses increased XTT and AP activity. A cell-type dependent action: a proapoptotic effect (increased Bax and caspase-3) in BeWo cells and an antiapoptotic effect (decreased Bax and increased cdk2 and cyclin D1) in JEG-3 cells was observed. Naphthalene, pyrene, and phenanthrene exhibited an endocrine-disrupting effect in JEG3 cells but not in BeWo cells. Our results provide evidence of cell specific effects of selected low molecular weight PAHs on proliferation, the cell cycle, proapoptotic protein expression, and hormone secretion.

Effects of human blood levels of two PAH mixtures on the AHR signalling activation pathway and CYP1A1 and COMT target genes in granulosa non-tumor and granulosa tumor cell lines.

Epidemiological studies have shown a link between problems with offspring of couples living in a contaminated environment in comparison to those who live in an uncontaminated environment. We measured the concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in maternal and cord blood. To explore the mechanism of the effects of PAH mixtures on nonluteinized granulosa cells (HGrC1) and granulosa tumor cells (COV434), as well as cell proliferation and apoptosis, we investigated the effect of PAH mixtures on the expression of the aryl hydrocarbon receptor (AHR), aryl hydrocarbon receptor nuclear translocator (ARNT) and aryl hydrocarbon receptor repressor (AHRR) genes, as well as the expression and activity of target genes cytochrome P450 1A1 (CYP1A1) and catechol-O-methyltransferase (COMT). The cells were exposed to mixture 1 (M1), composed of all 16 priority PAHs, and mixture 2 (M2), composed of five PAHs which are not classified as human carcinogens, and which are observed in the highest amounts both in maternal and cord blood. All 16 priority PAHs were bioavailable in maternal and cord plasma, suggesting that perinatal exposure should be considered. In HGrC1 cells, M1 increased AHR and ARNT, but decreased AHRR expression, in parallel with increased CYP1A1 and COMT expression and activity. M2 decreased AHR and AHRR, and increased ARNT, with no effect on CYP1A1 expression and activity; however, it did increase COMT expression and activity. In tumor cells, M1 lowered AHR and up-regulated AHRR and ARNT expression, consequently decreasing CYP1A1 expression and COMT activity. M2 up-regulated AHR and ARNT, down-regulated AHRR, and had no effect on CYP1A1 and COMT expression, but decreased COMT activity. We hypothesise that, dependent on composition, mixtures of PAHs activate the AHR differently through varying transcription responses: in HGrC1, a canonical AHR mechanism of M1, with activation of CYP1A1 important for detoxication, while in COV434, a noncanonical AHR mechanism, probably by activation the nuclear factor NFkB.

Depressive-like effect of prenatal exposure to DDT involves global DNA hypomethylation and impairment of GPER1/ESR1 protein levels but not ESR2 and AHR/ARNT signaling.

Several lines of evidence suggest that exposures to Endocrine Disrupting Chemicals (EDCs) such as pesticides increase the risks of neuropsychiatric disorders. Despite extended residual persistence of dichlorodiphenyltrichloroethane (DDT) in the environment, the mechanisms of perinatal actions of DDT that could account for adult-onset of depression are largely unknown. This study demonstrated the isomer-specific induction of depressive-like behavior and impairment of Htr1a/serotonin signaling in one-month-old mice that were prenatally exposed to DDT. The effects were reversed by the antidepressant citalopram as evidenced in the forced swimming (FST) and tail suspension (TST) tests in the male and female mice. Prenatally administered DDT accumulated in mouse brain as determined with gas chromatography and tandem mass spectrometry, led to global DNA hypomethylation, and altered the levels of methylated DNA in specific genes. The induction of depressive-like behavior and impairment of Htr1a/serotonin signaling were accompanied by p,p'-DDT-specific decrease in the levels of estrogen receptors i.e. ESR1 and/or GPER1 depending on sex. In contrast, o,p'-DDT did not induce depressive-like effects and exhibited quite distinct pattern of biochemical alterations that was related to aryl hydrocarbon receptor (AHR), its nuclear translocator ARNT, and ESR2. Exposure to o,p'-DDT increased AHR expression in male and female brains, and reduced expression levels of ARNT and ESR2 in the female brains. The evolution of p,p'-DDT-induced depressive-like behavior was preceded by attenuation of Htr1a and Gper1/GPER1 expression as observed in the 7-day-old mouse pups. Because p,p'-DDT caused sex- and age-independent attenuation of GPER1, we suggest that impairment of GPER1 signaling plays a key role in the propagation of DDT-induced depressive-like symptoms.

The variability of PCDD/F concentrations in the effluent of wastewater treatment plants with regard to their hydrological environment.

The occurrence, concentrations, patterns, and loads of 17 2,3,7,8-substituted congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in treated wastewater collected at the outlets from 14 wastewater treatment plants (WTPs), divided into three size categories. The analysis also considered the effect of wastewater outflow on the final concentrations of PCDDs/Fs, as the samples were collected during flooding and stable hydrological conditions. None of the studied WTPs were found to completely remove toxic congeners of PCDDs/Fs from wastewater: the PCDD concentrations in the outgoing effluent during stable wastewater flow ranged from 2.99 to 177.19 pg/L, PCDFs from 6.05 to 51.30 pg/L, and the Toxic Equivalent (TEQ) was between 0.94 and 4.87 pg/L. The results from high wastewater flow were less diversified, ranging from 5.04 to 8.85 pg/L for PCDDs, from 11.47 to 32.33 pg/L for PCDFs and from 2.00 to 4.65 pg/L for TEQ. The smallest WTPs demonstrated the highest average total and TEQ concentrations due to limited volume, short retention time and outdated technology, and, hence, insufficient treatment efficiency. The largest WTPs have the potential to substantially affect the quality of river water, as despite being associated with the lowest concentrations, they released much greater volumes of treated wastewater and, hence, the greatest amounts of analyzed compounds. Elevated TEQ values were observed at high flow in all WTP size categories indicating the impact of high and stable wastewater flow on the concentrations of the observed PCDDs/Fs.

The Role of Hydrology in the Polychlorinated Dibenzo--dioxin and Dibenzofuran Distributions in a Lowland River.

Persistent organic pollutants such as polychlorinated dibenzo--dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are environmental contaminants that have widespread distribution and pose a serious threat to aquatic ecosystems. We conducted a study to quantify the distribution, patterns, and transport of PCDDs and PCDFs along the Pilica River in central Poland under different hydrological conditions to estimate the loads of these compounds and understand their fate in aquatic systems. Water samples were collected at five sampling points along the river that represent a range of hydrological conditions including flooding and stable and low water flows. Reduced river water flow was associated with lower average total and toxic equivalent (TEQ) concentrations of PCDDs plus PCDFs: 33.6 pg L and 4.21 pg TEQ L for flooding; 28.3 pg L and 3.6 pg TEQ L for stable flow; 18.4 pg L and 1.0 pg TEQ L for low-water flow. Similar results were observed for daily loadings of total and TEQ concentrations: the highest values were observed during flooding (331.1-839.4 mg d and 27.8-110.7 mg TEQ d), medium under stable hydrological conditions (55.8-121.0 mg d and 7.7-15.3 mg TEQ d), and the lowest values during low water flow (30.9 and 40.3 mg d and 1.4-2.4 mg TEQ d). The results demonstrate that diffuse sources of pollution play a key role during periods of high water flow (i.e., flooding season), whereas point sources of pollution, including municipal and industrial wastewater treatment plant discharges, mainly determine the PCDD and PCDF concentrations seen during low water periods.

Study on the impact of industrial flue gases on the PCDD/Fs congener profile in ambient air.

The aim of this study was to examine the impact of emissions from combustion processes from sinter, medical, waste and sewage waste incineration plants on the PCDD and PCDF congener profile in ambient air in Krakow (city in Poland). The subject matter of the study were air samples from the outskirts and the city center. It was found that in flue gases from industrial sources and in ambient air the share of PCDF congeners in relation to the total content of PCDD/Fs was higher than the share of PCDDs. However, in air samples collected in the city center, this relationship was reversed. The PCDD congener profiles in flue gases and in air samples are comparable. However, in the samples from the city centre, the share of OCDD is significantly higher and amounts to about 80%. The PCDF congener shares show higher spatial diversity, although in all the analyzed air samples, ODCF and 1,2,3,4,6,7,8 HpCDF dominated. Analyzing the share of congeners in regard to the sum of PCDDs/Fs a mutual resemblance of air from the suburbs, exhaust gases from the sinter ore and sewage sludge incinerator plant was observed. The study showed a similarity between the profile of congeners in air from the city centre and exhaust gases from the medical waste incinerator.

Determination of hexabromocyclododecane by flowing atmospheric pressure afterglow mass spectrometry.

The first application of a flowing atmospheric-pressure afterglow ion source for mass spectrometry (FAPA-MS) for the chemical characterization and determination of hexabromocyclododecane (HBCD) is presented. The samples of technical HBCD and expanded polystyrene foam (EPS) containing HBCD as a flame retardant were prepared by dissolving the appropriate solids in dichloromethane. The ionization of HBCD was achieved with a prototype FAPA source. The ions were detected in the negative-ion mode. The ions corresponding to a deprotonated HBCD species (m/z 640.7) as well as chlorine (m/z 676.8), nitrite (m/z 687.8) and nitric (m/z 703.8) adducts were observed in the spectra. The observed isotope pattern is characteristic for a compound containing six bromine atoms. This technique is an effective approach to detect HBCD, which is efficiently ionized in a liquid phase, resulting in high detection efficiency and sensitivity.

Influence of a municipal waste landfill on the spatial distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) in the natural environment.

The paper presents the influence of a municipal waste landfill on the pollution of soil, plants and groundwater by polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs). Analysis of their migration in the environment was made in relation to the direction of groundwater flow in the study area. Determination of PCDDs/Fs was performed by isotope dilution high resolution chromatography/tandem mass spectrometry (ID-HRGC/MS-MS) on a Thermo Scientific GCQ-1100/Trace2000 system equipped with an Xcalibur data acquisition and analysis software. The content in soil was in the range of 0.04-27.3pg I-TEQg(-1) of soil dry mass and decreased with depth. Similar values were obtained for plants: in Solidago virgaurea L. there were 0.13-1.9pg I-TEQg(-1) dry mass and in grass from the Family Poaceae - 0.12-3.18pg I-TEQg(-1) dry mass. The concentration in groundwater reached 1.16-6.6pg I-TEQdm(-3); the highest concentration was obtained in water samples collected from a ditch collecting leachates from the landfill. The study has shown that the analyzed object is not responsible for PCDDs/Fs emission to the environment. The increased concentration of these compounds in the topsoil may be influenced by processes linked with waste management (transportation and unloading) and other localized sources of low emission located beyond the landfill.

Photoperiod modulates access of 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) to the brain and its effect on gonadotropin and thyroid hormones in adult ewes.

The effects of photoperiod on the cerebrospinal fluid (CSF) concentration of six ortho-substituted polychlorinated biphenyls (PCBs: PCB28, PCB52, PCB101, PCB138, PCB153, and PCB180), the effects of an orally administered low dose of PCB153 (0.3mg/kg, three times a week for three weeks) on PCBs and thyroid hormones (THs) concentrations in the CSF and plasma, and the release of luteinizing hormone (LH) were determined in ovariectomized, estradiol-implanted ewes (2.5 years old) maintained indoors under artificial long day (LD, 16L: 8D) and short day (SD, 8L: 16D) conditions. Concentrations of two PCBs (PCB28 and PCB153) in the plasma and four PCBs in the CSF (PCB101, PCB138, PCB153, and PCB180) were significantly higher during LD than SD. Following PCB153 treatment, its concentration in the plasma was higher in SD (1.2 ± 0.3 ng/ml) than LD (0.2 ± 0.05 ng/ml), but similar in the CSF (10.2 ± 3.7 pg/ml vs. 13 ± 0.7 pg/ml) under both photoperiods. During SD, the concentration of PCB153 in the CSF was higher in treated animals than controls, while no differences were noted under LD. These findings indicate that in ewes, exposure of the brain to more highly chlorinated, ortho-substituted PCBs may be modulated by photoperiod. PCB153 treatment had no effect on plasma THs, but reduced total triiodothyronine concentration during LD and free thyroxine during SD in the CSF. Under both photoperiods, PCB153 reduced basal plasma LH and reinforced the inhibition of pulsatile LH release during LD. As PCB153 reduced LH and THs (which are involved in the seasonal control of reproduction in ewes), it may have a braking effect on seasonal transitions between active and inactive phases of reproduction.

Study on the determination of PCDDs/Fs and HCB in exhaust gas.

The subject of this study was to develop a method of simultaneous determination of PCDDs/PCDFs and HCB in exhaust gases from industrial installations. Sampling to determine PCDDs/PCDFs was conducted using the method described in PN-EN 1948-1: 2006, where the sorption material is polyurethane foam (PUF). In order to simultaneously collect PCDDs/PCDFs and HCB and to avoid sorbent bed breakthrough, it was necessary to apply an additional polyurethane sorption layer. Twenty-seven samples of exhaust gases from various cement plants and 40 samples of exhaust gases from hospital and industrial waste incineration plants collected in 2009/2010 in the entire territory of Poland were examined. The average content of PCDDs/Fs in samples from cement plants amounted to 0.076 ng I-TEQ N m(-3) (range of 0.002-0.62 ng I-TEQ N m(-3)), while the average content of HCB amounted to 10 ng N m(-3) (range of 0.98-60.5 ng N m(-3)). In the case of samples collected from waste incineration plants, the average concentration of PCDDs/Fs was 0.39 ng I-TEQN m(-3) (range of 0.002-5.68 ng I-TEQ N m(-3)). In the case of HCB, the average concentration was 238 ng N m(-3) (range of 3.21-2500 ng N m(-3)). Also, the interdependence of the concentration of PCDDs/PCDFs and HCB was determined in the analysed samples, with the ranges of low and high content of PCDDs/PCDFs being examined separately. In all cases, the determined values of the r correlation coefficient were within the range of 0.7-1.0, which indicates a good correlation between the concentrations of PCDDs/PCDFs and HCB.

PBB levels in fish from the Baltic and North seas and in selected food products from Poland.

Recently, a significant amount of attention has been devoted to the determination of polybrominated biphenyls in food and the environment. In this study, PBB contamination of fish from the North and Baltic Seas, with a special focus on samples from Poland and France, was investigated. North Sea fish like salmon, herring, scarp, gilthead seabream and grey gurnard were collected from a French fish market. Baltic Sea fish like salmon, tunny, trout, herring, and freshwater fish such as carp were purchased from a Polish fish market. Cod livers in oil were also analyzed in this study. As additional food samples, butter, pork fat and beef fat were tested. Concentrations of PBBs in North Sea fish (except herring) were higher than in fish from the Baltic Sea. The highest total PBB concentration was measured in scarp muscle tissue (635+/-107 pg g(-1) wet weight), and the lowest was in carp samples (0.567+/-0.245 pg g(-1) wet weight). The PBB content in tunny oil samples was below the detection limits (0.45-1.05 pg g(-1)fat). Our study also demonstrated that PBBs may bioaccumulate in the liver, where PBB concentrations were 2116+/-351 pg g(-1) wet weight and 841+/-147 pg g(-1) wet weight. In fish species from Poland, the most dominant congeners were tetrabromobiphenyls, followed by pentabromobiphenyls and hexabromobiphenyls. In some species of fish from the North Sea, the most dominant groups were hexabromobiphenyls and tetrabromobiphenyls. Although the relative abundances of structurally known and unknown isomers varied from species to species, all fish (except tunny) were contaminated with PBBs.

PCDDs/PCDFs, dl-PCBs and HCB in the flue gas from coal fired CFB boilers.

The aim of the project was to measure the actual emissions of polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs) and hexachlorobenzene (HCB) from four selected power plants in Poland in order to update the national inventory of PCDDs/PCDFs emission. Relatively low PCDDs/PCDFs as well as dl-PCBs concentrations in flue gas obtained in measurements in this study for four different circulated fluidized bed (CFB) boilers indicate practical absence of any hazards caused by PCDDs/PCDFs emission from these units. The results of PCDDs/PCDFs determination obtained in this study indicate that hard coal combustion in large CFB in the four central heating plants (CHP) is not a significant source of PCDDs/PCDFs emission to the environment even if operated by co-firing of waste coal. PCDDs/PCDFs concentration in flue gases as well as emission factors were recorded in the range of 0.012-0.060 ng I-TEQ/m(n)(3) and 7.51-46.4 microg I-TEQ/TJ, respectively. Dl-PCBs concentration was practically below the LOQ=0.006 ng WHO-PCB TEQ/m(n)(3) in all experiments. HCB concentration as well as emission factors were recorded in the range of 11.5-42.0 ng/m(n)(3) and 6.19-26.7 mg/TJ, respectively, where the highest value was obtained for co-firing of waste coal, however. Obtained in this work emission factors will be used for national emission inventory purposes instead of the factors proposed by Toolkit or taken from previous measurements. However, consideration should be given to the fact that the measurements in most cases are related to single installations. Therefore, the need for further development of national factors for the power generation industry in Poland is desired.

Determination of PCDDs, PCDFs, PCBs and HCB emissions from the metallurgical sector in Poland.

BACKGROUND: The aim of the project was to measure the actual emissions of PCDD/F, PCBs and HCB from 20 selected metallurgical installations in Poland, in order to update the national inventory of dioxin emission from metallurgical industry for developing a strategy for dioxins and furans emission abatement from the subject facilities (UNEP 2005). METHODS: Sampling methodology used in this work was developed at the Cracow University of Technology because of the complexity of simultaneous sampling and determining PCDFs, PCDDs, PCB and HCB. For the determination a GC-MS/MS system was used. RESULTS AND DISCUSSION: Results from the work indicate that the highest dioxins and PCB concentrations were recorded for iron ore sintering plants at 1.10-1.32 ng total1 TEQ/Nm3 followed by aluminium scrap melting at 0.03-0.66 ng total TEQ/Nm3. The highest HCB concentrations at 613-1491 ng/Nm3 were also recorded fo iron ore sintering plants, whereas at aluminium plants the HCB concentrations were in the range of only 10.1-22.7 ng/Nm3. CONCLUSIONS: The above investigations indicate that secondary aluminium production is the most significant dioxins source, if calculated as emission factor values. However, iron ore sintering plants are operating at much higher production capacity, causing this process to become the major source of dioxins, PCB and HCB pollution to the atmosphere in Poland. RECOMMENDATIONS AND PERSPECTIVES: Based on the performed tests and the environmental reviews of selected plants several recommendations were formulated for the reduction of generation or of emission of these pollutants from iron ore sintering plants, electric arc furnace steel production processes, hot-blast furnace operations, secondary aluminium smelting and primary zinc production from zinc cathodes.

Catalytic destruction of 1,2-dichlorobenzene on V2O5-WO3/Al2O3-TiO2 catalyst.

Studies on the catalytic destruction of 1,2-dichlorobenzene were carried out on a specially constructed semi-technical equipment whose most important element was a catalytic reactor with a monolithic catalyst in the form of 150 x 150 x 100 mm cubes. A catalyst made from cordierite with an active layer composed of Al2O3 - 64 wt%, TiO2 - 26 wt%, V2O5 - 6.6 wt% and WO3 - 3.4 wt% was used. The reactor made it possible to carry out the process in the temperature range 150-350 degrees C, at variable catalyst loading and different velocities of gas flow through the reactor. The content of 1,2-dichlorobenzene in the air was analysed by a chromatographic method. A significant effect of catalyst loading and temperature on 1,2-dichlorobenzene destruction efficiency was observed and no effect of the linear flow velocity through the catalyst on o-dichlorobenzene destruction efficiency was reported. The applied vanadium-tungsten catalyst on a monolithic carrier made from TiO2/gamma-Al2O3 revealed very good activity that resulted in an over 80% efficiency of 1,2-dichlorobenzene destruction at the temperature around 250 degrees C at a very high catalyst loading reaching ca. 8200 h(-1). Additionally, in this study the kinetics of 1,2-dichlorobenzene decomposition was determined, specifying the order of reaction and dependence of the decomposition rate constant on temperature, using a simple power-rate law model.

Effect of surfactants on plasticizer biodegradation by Bacillus subtilis ATCC 6633.

The biodegradation of plasticizers has been previously shown to result in the accumulation of metabolites that are more toxic than the initial compound. The present work shows that the pattern of degradation of di-2-ethylhexyl adipate by Bacillus subtilis can be significantly altered by the presence of biosurfactants, such as surfactin, or synthetic surfactants, such as Pluronic L122. In particular, this work confirms that the monoester, mono-2-ethylhexyl adipate, is a metabolite in the breakdown of the plasticizer. This metabolite was proposed but not observed in earlier studies. Toxicity measurements showed it to be significantly more toxic than the plasticizer. Thus, the effect of the surfactants was to significantly increase the accumulation of one or both of the two most toxic metabolites; i.e., the monoester and 2-ethylhexanol. It was proposed that the most likely cause of the effect of the surfactants was the sequestering of these two metabolites into mixed micelles, resulting in their reduced availability for further degradation.

Origin of 2-ethylhexanol as a VOC.

2-Ethylhexanol has been identified as a volatile organic compound (VOC) that contributes to the deterioration of indoor air quality. Plasticizers are common components of dust and building materials and are shown to be degraded by a variety of bacteria and fungi to produce 2-ethylhexanol and other metabolites. Of these, the 2-ethylhexanol has significant volatility and was observed in appreciable quantities. The degree to which 2-ethylhexanol is observed as a VOC in air samples would be limited by the fact that many of the microorganisms that are capable of producing this compound are also able to oxidize it to 2-ethylhexanoic acid, which is much less volatile. It is argued that an abiotic degradation mechanism of plasticizers that results in the generation of 2-ethylhexanol is unlikely and, if this did occur, other metabolites should have been observed. Thus, the microbial degradation of plasticizers is the most likely source of 2-ethylhexanol in indoor air.

Effects of dioxin (2,3,7,8-TCDD) and PCDDs/PCDFs congeners mixture on steroidogenesis in human placenta tissue culture.

OBJECTIVE: The aim was to compare the direct effect of most toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as well as of naturally occurring congener mixture of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) extracted from fly ash on the placental steroidogenesis. The concentration of all 17 toxic congeners was reported and the toxic equivalent (TEQ) was calculated as a 27.7 micrograms-TEQ/kg of fly ash. METHODS: Placental cotyledons were harvested immediately after expulsion of placenta. The cells were prepared according to KLIMAN et al. (1986). To examine TCDD and PCDDs/PCDFs mixture action on cytochrome P450 side change cleavage enzyme (P450 scc) and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity the placental cells were cultured either in basal conditions or with the addition of 25-hydroxycholesterol (25-OH) or pregnenolone (P5). RESULTS: TCDD in all doses used decreased basal P4 secretion, while did not show any effect on 25-hydroxycholesterol (25-OH) and pregnenolone (P5) supplemented cultures. In all variants of culture PCDDs/PCDFs mixture was without effect on basal and substrate supplemented progesterone (P4) secretion suggesting a reduction in the activity of cytochrome P450scc or 3 beta-HSD. To examine TCDD and PCDDs/PCDFs mixture action on aromatase cytochrom P450 (P450 arom) activity the placental cells were cultured in basal condition or with the addition of dehydroepi-androsterone (DHEA) or testosterone (T). Significant increase of estradiol secretion under the influence of TCDD in DHEA and T supplemented cultures suggests its action on the activity of P450 arom. CONCLUSION: The discrepancy found between the action of pure TCDD and dioxin mixture on placental steroids secretion is possibly due to an additional effect of pentachlorodibenzo-p-dioxin (PeCDD) and pentachlorodibenzo-furan (PeCDF) which covered > 50% of the total toxic equivalents (TEQ) present in this mixture.

Survey of dioxin sources in the Baltic Region (extended summary).

The present paper summarises the results of the project: 'Survey of Anthropogenic Sources of Dioxins and Furans in the Baltic Region'. As a part of the project, inventories have been carried out in Estonia, Latvia, Lithuania and Poland by applying the toolkit for quantification of dioxin and furan releases developed by UNEP Chemicals. The main route of direct releases to the environment is emission to air. Total emission to air from Poland was estimated at 490 (88-1,300) g I-TEQ/year, whereas the emissions from Estonia, Latvia and Lithuania were estimated as being 14 (2.4-54), 23 (2.6-63) and 17 (2.6-38) g I-TEQ, respectively. In general, the uncertainty on the estimates is very high, and recommendations regarding further development of the inventories have been made, and measures for reducing the releases have been provided.