Seaweed accelerates the excretion of dioxin stored in rats

To prevent health problems of humans exposed to dioxin, it is important to enhance the fecal excretion of dioxin stored in the body. The effects of seaweed such as wakame, hiziki, and kombu on the gastrointestinal absorption and reabsorption of 17 types of polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) congeners was investigated in Wistar rats. Rats were fed 4 g of the basal diet or a seaweed diet containing PCDD and PCDF standard solution [233 ng of toxic equivalents (TEQ)/kg of body weight] once during the experiment period. In the group fed the 10% wakame diet, the levels of fecal excretion of PCDD and PCDF congeners were higher (p < 0.01) from days 1 to 5 by 2.8-fold for 2,3,7,8-TCDD, by 4.0-fold for 1,2,3,7,8-pentaCDD, by 3.4-fold for 1,2,3,4,7,8-hexaCDD, by 3.2-fold for 1,2,3,6,7,8-hexaCDD, by 2.5-fold for 1,2,3,7,8,9-hexaCDD, by 1.7-fold for 1,2,3,4,6,7,8-heptaCDD, by 1.1-fold for 1,2,3,4,6,7,8,9-octaCDD, by 3.0-fold for 2,3,7,8-tetraCDF, by 3.7-fold for 1,2,3,7,8-pentaCDF, by 3.7-fold for 2,3,4,7,8-pentaCDF, by 3.2-fold for 1,2,3,4,7,8-hexaCDF, by 3.0-fold for 1,2,3,6,7,8-hexaCDF, by 3.2-fold for 1,2,3,7,8,9-hexaCDF, by 2.9-fold for 2,3,4,6,7,8-hexaCDF, by 1.6-fold for 1,2,3,4,6,7,8-heptaCDF, by 2.2-fold for 1,2,3,4,7,8,9-heptaCDF, and by 1.2-fold for 1,2,3,4,6,7,8,9-octaCDF than those of the basal group, respectively. Rats were fed 4 g of the basal diet containing PCDD and PCDF standard solution (2991 ng of TEQ/kg of body weight) once on day 1 and then place on the basal diet for 7 days. After 1 week, the rats were fed either the basal diet or seaweed diet from days 8 to 35. In the group fed the 10% wakame diet, the levels of fecal excretion of PCDD and PCDF congeners were higher (p < 0.01 or p < 0.05) during the period from days 8 to 35 by 1.7-fold for 2,3,7,8-TCDD, by 1.8-fold for 1,2,3,7,8-pentaCDD, by 2.0-fold for 1,2,3,4,7,8-hexaCDD, by 1.9-fold for 1,2,3,6,7,8-hexaCDD, by 1.6-fold for 1,2,3,7,8,9-hexaCDD, by 1.5-fold for 1,2,3,4,6,7,8-heptaCDD, by 2.0-fold for 2,3,4,7,8-pentaCDF, by 2.1-fold for 1,2,3,4,7,8-hexaCDF, by 1.9-fold for 1,2,3,6,7,8-hexaCDF, by 1.7-fold for 2,3,4,6,7,8-hexaCDF, by 1.5-fold for 1,2,3,4,6,7,8-heptaCDF, and by 1.9-fold for 1,2,3,4,7,8,9-heptaCDF than those of the basal group, respectively. These findings suggest that the administration of seaweed such as wakame is efficient in preventing the absorption and reabsorption of dioxin from the gastrointestinal tract and might be useful in treatment of humans exposed to dioxin.     

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in food of animal origin. The Swiss dioxin monitoring program

Between 1997 and 1999, several cases of dioxin contaminations in foodstuffs of animal origin occurred in Europe due to feed contaminated by several independent sources: citrus pulp pellets, fat containing polychlorinated biphenyls (PCB), and kaolinitic clay as anti-caking agent in feedingstuffs. As a consequence of the latter, a survey on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in food of animal origin was initiated by the Swiss authorities to assess the extent of PCDD/F contamination and to document the efficiency of the measures taken to ensure the decontamination of the food supply. Investigation of a total of 128 samples of cow's milk, poultry, eggs, and meat revealed several cases of residue levels distinctly above the background exposure limit of approximately 2.5 ng of I-TEQ/kg (fat basis). Particularly, elevated concentrations were found in eggs (maximum 13 ng of I-TEQ/kg), poultry (maximum 3.9 ng of I-TEQ/kg), and pork (maximum 7.5 ng of I-TEQ/kg). On the basis of the observed PCDD/F congener pattern, the contamination could be attributed to PCDD/F-contaminated kaolin that was used as an anti-caking agent in particular feedstuffs.     

Concentration and distribution of polychlorinated biphenyls in soils of Moscow

The concentration of polychlorinated biphenyls (PCB) in the soils of Moscow has been determined by gas chromatography and high-resolution mass spectrometry (GC-HRMS). The total concentrations of 19 indicator and dioxin-like congeners, as well as PCBs in surface soils, are 2.85–60.62 μg/kg (the most contaminated sample was 4591.99 μg/kg). The average value, excluding the most contaminated sample, is 14.44 μg/kg, which is characteristic of residential areas of industrialized countries. This indicator varies insubstantially depending on the functional zone of the city. The toxicity equivalent of 12 dioxin-like PCBs in soils is 1.92 ng I-TEQ/kg on average and varies in a range from 0.15 to 334.12 ng I-TEQ/kg. The fraction of PCBs in the total toxicity of dioxins and dioxin-like compounds in soil varieties is 16.7–85.4%.     

白银市不同功能区表层土壤中PCDD/Fs分布特征研究

采用高分辨气相色谱高分辨质谱联用仪（HRGC/HRMS）对白银市不同功能区土壤样品中的17种2,3,7,8-PCDD/Fs的含量进行了测试,探讨了白银市典型区域表层土壤中PCDD/Fs的来源、分布特征。结果表明,白银市各类表层土壤中17种2,3,7,8-PCDD/Fs的I-TEQ浓度范围为0.42～8.56pg（I-TEQ）·g-1,均值为2.28pg（I-TEQ）·g-1,其中,工业区土壤中PCDD/Fs含量为0.42～8.56pg（I-TEQ）·g-1,均值为3.37pg（I-TEQ）·g-1;城市生活区PCDD/Fs的含量为0.50～1.83pg（I-TEQ）·g-1,均值为1.31pg（I-TEQ）·g-1;农业区含量为0.49～1.33pg（I-TEQ）·g-1,均值为1.01pg（I-TEQ）·g-1;两个背景点PCDD/Fs的含量分别为0.60和1.10pg（I-TEQ）·g-1。研究区域内PCDD/Fs的含量呈现工业区〉城市生活区〉农业区〉背景区的趋势,高氯代的PCDD/Fs异构体对土壤中二恶英毒性当量的贡献率较大。     

PCDD and PCDF in air,soil, vegetation and oily runoff from a tire fire

In early February 1990, vandals set fire to a used tire storage facility near Hagersville, Ontario, Canada, During the fire, the Ontario Ministry of Environment and Energy (MOEE) monitored the site and surrounding impact zone for numerous organic contaminants. Samples of air, soil, vegetation, runoff water, and oily residue were collected and analyzed for polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). Air samples produced complex incineration patterns with a large number of isomers detected. Total toxicity equivalents (TEQ) at 1 km downwind of the fire were an order of magnitude higher than those at 3 km downwind. Soil samples collected during the fire did not show elevated PCDD or PCDF concentrations, however, low concentrations were detected in vegetation collected at 100 m and 200 m from the site. PCDD and PCDF concentrations in the foliage decreased with time but were still detectable for at least 200 days after the fire started. As the tires burned, water used to extinguish the fire caused runoff of oil and oily water. Unique patterns of PCDDs and PCDFs were detected in these samples.     

Levels and trends of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in Spanish commercial fish and shellfish products, 1995-2003

The polychlorinated dibenzo-p-dioxin (PCDD), dibenzofuran (PCDF), and polychlorinated biphenyl (PCB) contents of 123 Spanish commercial salmon, tuna fish, sardine, oyster, mussel, and clam samples from 1995 to 2003 were investigated. A significant decrease of dioxin and non-ortho PCB concentrations in the studied species was found over the years. The decrease was greater in the case of dioxins than in that of non-ortho PCBs, especially during the early years of the study. PCB and PCDD/F concentrations in the years 2001-2003 were comparable to those reported in the literature for similar species collected after 1999. Mean PCB concentrations ranged from 3.46 ng/g of fresh weight (fw) in clams to 100 ng/g of fw in tuna fish. PCDD/F mean current levels ranged from 0.62 pg/g of fw in clams to 2.89 pg/g of fw in oysters. Toxic equivalent quantities (WHO-TEQ) ranged from 0.05 pg of WHO-TEQ(PCDD/Fs)/g of fw in clams to 0.5 pg of WHO-TEQ(PCDD/Fs)/g of fw in salmon (in the upper bound determination levels). When coplanar PCBs were included, the WHO-TEQ(PCDD/Fs+cop) (PCBs) values increased by a range of 1.7 times in oysters to 14.1 times in tuna fish. The decrease in dioxin concentrations suggests that efforts to control dioxin emissions and to reduce human exposure through foodstuffs are succeeding. The high contribution of PCBs to total WHO-TEQs in the fish and shellfish species investigated suggests that it is important to determine PCBs in foodstuffs, and especially in fish products, and they should be included in further research and future legislation.     

Chlorinated dibenzo-p-dioxin and dibenzofuran concentrations in beef animals from a feeding study

Four calves were fed polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans for 120 days at levels somewhat higher than what may be found in forage near some waste incinerators and manufacturing plants. Four calves were fed identical diets but without the chemicals. Using bioelectrical impedance measurements of total body fat, 30-50% of the dosed 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, and 2,3,4,7,8-PeCDF was estimated to be retained by the animals. Although these same congeners were bioconcentrated in adipose tissue (BCF approximately 10), consumer products such as ribeye showed concentrations less than what were found in the animal feed (BCF approximately 0.1). Distribution of the dioxins and furans into various lipid compartments appeared to be rather uniform in back fat, perirenal fat, and ribeye for tetra to hexa congeners. Ribeye, serum, and liver lipids had higher concentrations of the higher chlorinated congeners, due in part to not reaching a steady state. An unexpected source of dioxin and furan contamination was discovered during the experiment, resulting in the control animals having concentrations of some congeners that were equal to or in some cases greater than those of the dosed animals. Pentachlorophenol-treated wood components in the pole barn where the feeding experiment was conducted were found to have contributed to the animals' exposure.     

Determination of dioxins and furans in foods and biological tissues: review and update

Determination of trace residues of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) in various matrixes is carried out by a limited number of laboratories in the United States, Canada, and other countries. Current methods for analysis of foods and biological tissues include a combination of preparation, extraction, cleanup, isolation, determination, and identity confirmation procedures. Soxhlet, liquid/liquid, solid-phase, and column extraction procedures are used as well as treatment with acid or base before solvent extraction. Cleanup and isolation steps include sulfuric acid partitioning; adsorption chromatography on Florisil, silica gel, or alumina; gel permeation chromatography; multi-stage column chromatography on sulfuric acid silica and alkali silica; carbon column chromatography; and liquid chromatography fractionation with size exclusion, normal-phase, and reverse-phase columns. Activated carbon and multistage chromatographic columns are widely used in cleanup schemes. Isomer-specific identification and quantitation of PCDD and PCDF congeners at parts-per-trillion levels or lower are carried out by high resolution (capillary) gas chromatography (HRGC) and multiple ion detection mass spectrometry. In addition to chemical methods, bioassay procedures have been recommended (e.g., use of monoclonal antibodies, for immunoassay determination of PCDDs and PCDFs).     

Bioaccumulation of PCDD/Fs and Co-PCBs in Lower-Trophic-Level Organisms in Sendai Bay,Japan

In Sendai Bay, Japan, the total PCDD, PCDF, and Co-PCB (dioxins) concentrations in phytoplankton were equivalent to 150, 12, and 51 pg/g wet weight (ww), respectively. The average concentrations in seaweed were 3, 0.095, and 2.1 pg/g ww, respectively. The total concentrations in phytoplankton were much higher than those in seaweed, even though both groups are algae. The concentrations in zooplankton were 11, 1.1, and 110 pg/g ww, respectively. The total PCDD/F concentrations in zooplankton (primary consumers and lower-trophic-level invertebrates) were lower than in phytoplankton (primary producers), but the total Co-PCB concentration in zooplankton was higher than that in phytoplankton. The concentrations in mysids (secondary consumers and higher-trophic-level invertebrates) were 190, 18, and 290 pg/g ww, respectively. The average concentrations in shrimp (secondary consumers and higher-trophic-level invertebrates) were 120, 17, and 410 pg/g ww, respectively. The concentrations in higher-tropic-level invertebrates were higher than those in lower-trophic-level invertebrates. The average concentrations in sand lance were 4.5, 1.7, and 550 pg/g ww, respectively. The total PCDD concentration in sand lance was lower than that in zooplankton (prey of sand lance), but the total Co-PCB concentration in sand lance was higher than that in zooplankton. The bioaccumulation of PCDD congeners in sand lance differed from that of Co-PCB congeners. The bioaccumulation of PCDD/Fs from lower- to higher-trophic-level invertebrates through the food web differed from that from lower-trophic-level invertebrates to fish.     

Polychlorinated dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxins,dibenzofurans, and biphenyls in soils of Moscow

The contents of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) in the soils of Moscow were estimated. The concentrations of PCDDs and PCDFs mainly vary in the range of 0.27–16.1 ng WHO-TEQ/kg with single points of very high contamination up to 57.3 ng WHO-TEQ/kg; the concentrations of PCBs are in the range of 2.1–50.8 ng/g with sites of high contamination up to 4020 ng/g. The contribution of dioxin-like PCBs to the total dioxin toxic equivalent is very high: from 16 to 85%. The high levels of PCDDs and PCDFs in the soils indicate the strong contamination of the atmospheric air. The main source of these compounds is apparently motor transport.     

Determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin in fish, using electron capture gas chromatography with confirmation by mass spectrometry: interlaboratory study

An interlaboratory study of the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in fish was conducted by 6 analysts in 4 laboratories using high resolution gas chromatography with electron capture detection (HRGC-EC) for quantitative screening analysis. Samples consisted of 3 Great Lakes channel catfish homogenates containing different levels of bioincurred 2,3,7,8-TCDD; 1 of these was prepared in duplicate and another was prepared both with and without standard 2,3,7,8-TCDD fortification for a total of 5 samples per set. All methods used included addition of 1,3,7,8-TCDD surrogate (to correct for procedural losses) followed by ethanolic KOH digestion and hexane extraction. Certain cleanup steps used, including sulfuric acid washing and multidimensional column liquid chromatographic procedures, varied among laboratories. Mean HRGC-EC results for the bioincurred residues were 56.6, 25.2, and 7.7 pg/g (ppt) with corresponding relative standard deviations (RSDs) of 9.1, 18.6, and 53.2%. Average determination of standard 2,3,7,8-TCDD from the fortified sample (corrected for surrogate recoveries averaging 74.6%) was 106% of the added amount (30.9 pg/g) with 11.0% RSD. HRGC-multiple ion detection mass spectrometry (MS), monitoring 12 ions, was used for confirmation. With the exception of several results from 1 analyst, HRGC-MS and HRGC-EC quantitations were in good agreement. All but 1 result reported met all of the MS identity criteria.     

Uptake and transfer of PCDD/Fs by cattle fed naturally contaminated feedstuffs and feed contaminated as a result of sewage sludge application. 2. Nonlactating cows.

The dietary absorption and tissue distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was investigated in 4 nonlactating Simmental cows. During Phase 1 the dietary uptake and fecal excretion of these chemicals were measured over 10 days using feed containing background levels of PCDD/Fs that were primarily of atmospheric origin. Following this, two of the animals were sacrificed and samples of different fat, muscle, and organ tissues were collected. In Phase 2 the remaining two animals were fed grass silage from a field which had a history of repeated sewage sludge applications. During the last 10 days of the 27-day feeding period, the dietary uptake and fecal excretion of PCDD/Fs were again quantified, after which these two animals were also sacrificed and sampled. The dietary absorption of the PCDD/Fs in the nonlactating cows agreed well with values reported in Part I of this series for lactating cows. In the two animals sacrificed at the end of Phase 1 that were close to a contaminant steady state, the lipid-normalized concentrations were similar in almost all tissues. The exceptions were the liver, and to a lesser extent the lungs and the spleen, which had higher levels; and the degree of elevation increased with the degree of chlorination of the PCDD/Fs. During Phase 2, the animals' body burden of several of the PCDD/F congeners increased markedly. The tissue analyses indicated that the chemicals were initially sequestered primarily in the liver, from where they were redistributed to the other tissues and organs. The rate of redistribution was related to the perfusion of the organ/tissue and decreased in the order lung>spleen>kidney>muscle>fat tissue. The rate of redistribution also decreased with increasing degree of chlorination of the PCDD/F congeners. Whereas virtually all of the 1,2,3,7,8-Cl(5)DD taken up during Phase 2 had been deposited in fat tissue by the end of the 27-day feeding period, three-quarters of the Cl(8)DD was still in the liver.     

An assessment of the concentrations of PCDDs/Fs in contaminated bottom sediments and their sources and ecological risk

Purpose

The purpose of the study was to determine the levels of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F), two types of persistent organic pollutant (POP), in an urban retention reservoir located in an industrial zone within a coal-mining region. It also assesses the potential ecological risk of the PCDDs/Fs present in bottom sediments and the relationship between their content and the fraction of organic matter.

Materials and methods

The sediment samples were collected from Rybnik Reservoir, located in the centre of the Rybnik Coal Region, Silesia, one of Poland’s major industrial centres. Seventeen PCDD/F congeners in the surface of the sediments were analysed using high-resolution gas chromatography and high-resolution mass spectrometry (HRGC/HRMS).

Results and discussion

The toxic equivalency (TEQ) of the PCDDs/Fs in the sediments ranged from 1.65 to 32.68 pg TEQ g^?1. PCDDs constituted 59–78% of the total PCDDs/Fs, while the PCDFs accounted for 22–41%. The pattern of PCDD/F congeners in the sediments was dominated by OCDD. However, the second-most prevalent constituents were OCDF and ∑HpCDFs in the low TOC sediment (< 10 g TOC kg^?1), but HpCDD in the rich TOC samples (> 10 g TOC kg^?1). PCDD/F concentrations in the sediment samples were 2- to 38-fold higher than the sediment quality guidelines limit, indicating high ecological risk potential. Although a considerable proportion of PCDDs/Fs in the bottom sediments from the Rybnik Reservoir were derived from combustion processes, they were also obtained via transport, wastewater discharge, high-temperature processes and thermal electricity generation. The PCDD/F concentrations were significantly correlated with all fractions of organic matter; however, the strongest correlation coefficients were found between PCDDs/Fs and humic substances. Besides organic matter, the proportions of silt/clay fractions within sediments played an important role in the transport of PCDDs/Fs in bottom sediments.

Conclusions

The silt/clay fraction of the bottom sediments plays a dominant role in the movement of PCDDs/Fs, while the organic matter fraction affects their sorption. The results indicate that the environmental behaviour of PCDDs/Fs is affected by the quantity and quality of organic matter and the texture of sediments.

     

Toxic potency of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in food samples from Catalonia (Spain)

A surveillance program on polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in 29 foodstuff samples produced all over the four provinces in Catalonia (Spain) is presented. The study included the analyses of milk, egg, meat (beef, chicken, and pork), mussel, and olive oil samples. A previously developed method for the simultaneous analysis of the 2,3,7,8-substituted PCDDs/PCDFs and the dioxin-like PCBs, as well as the indicator PCBs, was employed. Total toxicity equivalent (TEQ) values were calculated using the toxicity equivalent factors (TEFs) proposed by the World Health Organization (WHO) for dioxin-like PCBs, PCDDs, and PCDFs. The TEQ(PCDD/F) levels were below the limits proposed in the draft of the EC regulation for food commercialization in the European countries. These limits are the following: 2 pg WHO-TEQ/g fat for pork, 3 pg WHO-TEQ/g fat for milk and chicken, 5 pg WHO-TEQ/g fat for egg and beef, and 3 pg WHO-TEQ/g whole product for fish. The contributions of PCDDs/Fs and dioxin-like PCBs in the total toxicity of the samples were calculated for each matrix. The results showed that the TEQ(PCB) contribution varied from 27% in olive oil samples to 81% in mussel samples. These findings suggest that the regulation of TEQ contents in food should include not only the TEQ(PCDD/F), but also the TEQ(PCB).     

Einfluß polychlorierter Biphenyle auf die mikrobielle Aktivität in Böden

Effects of polychlorinated biphenyls on soil microbial activity In laboratory experiments the microbial toxicity of the PCB congeners 5 (2, 3-Dichlorobiphenyl), 8 (2, 4′-Dichlorobiphenyl), 29 (2. 4, 5-Trichlorobiphenyl) and 77 (3, 3′, 4, 4′-Tetrachlorobiphenyl) which is supposed to be extremely toxic to wildlife was investigated using Parabrownearth-Ap and Podsol-Ahe horizon material. In addition the technical PCB mixtures Arochlor 1242 and 1260 were tested. Microbial toxicity was measured by means of long-term respiration (CO₂-evolution), short-term respiration (CO₂-evolution 12 h, after addition of glucose), and dehydrogenase activity (TTC reduction) tests. 1 mg/kg of the Dichlorobiphenyls 5 and 8 reduced the long-term and short-term respiration of the Podsol-Ahe during the whole experiment (35 and 28 days, respectively). The Trichlorobiphenyl 29 became effective after addition of 10 mg/kg. No effect except a short stimulation of long-term respiration was observed for PCB 77 (Tetrachloro-PCB). Due to its higher sorption capacity, all PCB congeners reduced the microbial activity of the Parabrownearth-Ap to a lower degree. In general the toxicity of PCBs decreased with increasing degree of chlorination in both soil horizons. The technical mixtures reduced the long-term respiration only after high additions of 50 mg/kg (Podsol-Ahe) and 100 mg/kg (Parabrownearth-Ap), respectively. Arochlor 1242 proved to be more toxic than Arochlor 1260.     

Effects of Dibenzo-<Emphasis Type="Italic">p</Emphasis>-Dioxins/Dibenzofurans on Acetylcholinesterase Activity and Histopathology of the Body Wall of Earthworm <Emphasis Type="Italic">Eisenia andrei</Emphasis>: a Potential Biomarker for Ecotoxicity Monitoring

The polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) are persistent environmental pollutants. Recently, there have been an increasing demand to assess different biomarkers as early alarming indicators of environmental pollution. This study is the first to investigate the effects of PCDD/Fs on acetylcholinesterase (AChE) activity and histopathology of the body wall (epidermis, circular, and longitudinal muscles) of earthworm Eisenia andrei (Oligochaeta, Lumbricidae) using acute filter paper toxicity test. It is also exploring the selected biomarkers as a potential tool for evaluating soil quality. Earthworms were exposed to 0, 0.5, 1.0, and 1.5 ng/cm² PCDD/Fs. The treated worms expressed progressive abnormal morphological signs with incrementing doses of dioxins, such as coiling, curling, and body swelling. At the highest dose, some worms demonstrated skin discoloration, loss of body segmentation, and body part detachment. The AChE activity was significantly decreased (p < 0.001) in all treated animals compared to control. The mixture induced circular muscle hyperplasia at 0.5 ng/cm². However, the mixture at 1.5 ng/cm² caused epidermal atrophy with cell pyknosis and necrosis in all layers of the body wall. Image analysis revealed significant reduction in the thickness of the epidermis (p < 0.001) at all doses with relative to control. Herein, we report that 48 h of acute exposure of E. andrei to dioxins/furans induced morphological changes, reduced the activity of AChE, and induced histopathological alterations. The outcomes can be utilized as endpoints that could be added to earthworm’s standardized short tests for ecotoxicity studies.     

Effect of smoking process on changes in the content of selected non-ortho- and mono-ortho-PCB congeners in mackerel slices

The study involved determination of changes in the content of toxic dioxin-like coplanar non-ortho (PCB 77, PCB 126, PCB 169) and mono-ortho (PCB 156, PCB 157, PCB 114) congeners in mackerel slices during cold and hot smoking. In addition, the risk of toxicological exposure of the consumers of examined smoking products was assessed by calculating toxic equivalency (TEQs) in relation to 2,3,7,8-TCDD dioxin. In the final stages of hot smoking a small increase was observed in the content of analyzed compounds due to the presence of PCBs in the smoke. The main factor determining the changes in the content of these compounds in fish slices may have been their loss with the lipid leakage and in codistillation with water vapor. The hot smoking of mackerel slices contributed to a decrease in the content of examined non-ortho- and mono-ortho-PCB congeners in final products and in consequence to a drop of TEQs by 14.2%. On the other hand, cold smoking led to a rise in the content of analyzed PCB congeners in the final product, which significantly affected the increase of TEQs level by 31.7% in relation to initial raw material.     

Coexposure of dioxin-like polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins and dibenzofurans in free-range hens and implications derived from congener profile analysis

The consumption of free-range eggs is becoming more popular worldwide. We analyzed the levels of 12 dioxin-like polychlorinated biphenyls (dl-PCBs) and their congener profiles from 6 free-range and 12 caged egg samples. The mean levels of dl-PCBs in the free-range samples were 5.4 times higher than those in caged eggs. All egg samples exhibited at least two characteristic dl-PCB congener patterns, which reflected distinctive contamination sources. Additionally, for the first time, we demonstrated that the dl-PCB levels in the free-range eggs were highly correlated with elevated levels of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) (r = 0.986; p < 0.001), indicating a coexposure scenario in free-range hens. Cluster analysis of congener patterns implied that this coexposure scenario could be attributed to distinct dl-PCB and PCDD/F sources. This congener profile information provides insights from a different perspective for further identifying potential dl-PCB and PCDD/F sources in the polluted free-range eggs.     

High resolution gas chromatographic analysis of nonpolar chlorinated hydrocarbons in human milk

A gas chromatographic method is described for the analysis of human milk to determine polychlorinated biphenyls (PCBs) as 72 congeners plus p,p'-DDE, mirex, hexachlorobenzene, and octachlorostyrene. The detection limit for individual compounds is about 0.05 ng/g when 30 g milk is analyzed. Total PCBs can be estimated with a detection limit of 1-5 ng/mL milk. Analytical precision is better than +/- 10% for all compounds at 20-50 ng/mL whole milk.