Seasonal peculiarities of PCDD/Fs levels in bank voles inhabiting sites in the vicinity of the landfill with municipal wastes (Moscow, Russia).

Differences in PCDD/Fs concentrations were registered among adult bank voles (Myodes glareolus) inhabiting forest in the vicinity of the Landfill Salariyevo (Moscow, Russia) and caught in early spring (over-winter survivors) and late summer. The levels of highly toxic congeners and WHO-TEQ05 in samples of wintering voles were much lower than those in samples got in summer. This difference was investigated analyzing PCDD/Fs in sexually matured animals and offspring obtained in vivarium. Practically, no significant differences of PCDD/Fs concentrations and general toxicity were revealed among sexes. The main impact to these seasonal differences in PCDD/Fs accumulation was assigned to the types of functional development and activity, diet variation as natural growth of all voles occurs on the same territory but in seasonally diverse conditions. So, the species functional ecology (lifestyle and seasonal features) should be considered in practical application of animal models from natural populations for local monitoring of PCDD/Fs body burden, and individual functional type of ontogenesis among cyclomorphic mammalian species, especially. Thus, the results obtained during monitoring should be carefully interpreted for a proper environmental management.

Fingerprinting and source apportionment of dioxin contamination of soils and chicken eggs in Southeast and Central Vietnam.

Free-range chicken eggs and topsoil samples from private households in Southeast and South Central Coast of Vietnam were investigated to identify potential PCDD/F sources using Positive Matrix Factorization (PMF) approach. The PMF-extracted egg congener patterns were transformed to soil patterns using bioaccumulation factors and then compared to extracted soil and known dioxin sources patterns described in the literature. Free-range chicken egg PCDD/F profiles allowed to more precisely identify and distinguish potential PCDD/F sources. Five main PCDD/F sources were identified: open burning, vehicle emissions, background atmospheric deposition, Agent Orange, and so-called OCDD dechlorination pattern. The latter is characteristic for natural formation or ultimate weathering under tropical conditions of any primary source with predominant OCDD. Agent Orange source contribution ranged from 48 to 96% in soils, from 9 to 94% in eggs in hotspots, and from 10 to 31% in soil and from 4 to 45% in eggs in sprayed areas, respectively. Contributions of other sources varied significantly between sites.

Geographical distribution of dioxins, cadmium, and mercury concentrations in reindeer liver, kidneys, and muscle in the Russian Far North.

Reindeer herding is a vitally important agricultural sector in the Russian Far North. It is believed that Northern ecosystems readily accumulate persistent pollutants because of trophic chains and climate features peculiar to the region. Reindeers graze on vast areas, and their seasonal migrations to distances of up to hundreds of kilometers in the North-South direction increase the likelihood of crossing a locally polluted area. Here, we present the results of a large-scale nationwide study of reindeer liver, kidneys, and muscle pollution by dioxins, cadmium, and mercury. Samples were taken in 2015-2020 from 41 locations in 8 reindeer-herding regions of Russia. Dioxins were determined in 383 samples of liver and 13 of muscle, and cadmium and mercury-in 505 samples of liver, 315 of kidneys, and 22 of muscle. Dioxin pollution has shown a clear geographical trend, i.e., liver concentrations of dioxins steadily decrease from the Western to the Eastern parts on the Russian Far North, with the highest concentration of 76.5 pg/g of fat WHO-TEQ. The discovered trend may be explained by the pattern of chemical plants' localization and by the density of reindeer population (as known from the literature sources). The highest concentrations of metals were found in kidneys (7.3 mg/kg of cadmium and 1.1 mg/kg of mercury). The contribution of local sources to cadmium and mercury pollution was found to be less than expected. We also suggest that reindeer liver may serve as a good additional indicator of environmental pollution by dioxins and heavy metals.

Novel Extract from Beetle Ulomoides dermestoides: A Study of Composition and Antioxidant Activity.

A biologically active extract from the darkling beetle Ulomoides dermestoides was obtained using the electro-pulse plasma dynamic extraction method. The beetle water extract contained a complex of antioxidant substances such as antioxidant enzymes and nonprotein antioxidants, as well as a complex of heat shock antistress proteins. This determines the rather high antioxidant activity of the aqueous extract of the beetle, i.e., 1 mg of dry matter/mL of the extract has an equivalent antioxidant activity to 0.2 mM Trolox (a water-soluble analog of vitamin E). It was shown that the beetle extract can lead to a 25-30% increase in the average lifespan of nematode Caenorhabditiselegans, under normal conditions, and a 12-17% increase under conditions of oxidative stress (with paraquat), and significantly inhibits the fructosylation reaction of serum albumin. Therefore, the beetle aqueous extract shows promise as a biologically active complex exhibiting antioxidant activity.

Solid phase extraction of PCDDs/PCDFs and dioxin-like PCBs from edible oils and fats.

We have studied the feasibility of solid phase extraction of PCDDs/PCDFs and dioxin-like PCBs from oils and fats as the first step of a sample preparation procedure that would not involve the chemical decomposition of the matrix. A few experimental setups using dual-layer columns packed with various brands of active carbon were tested. The use of a dual-layer microcolumn with AX-21 and Carboxen 1000 carbons for dioxins extraction from animal fats, vegetable oils and powdered milk gave satisfactory recoveries which met the European Union Commission Regulation 2017/644 criteria for dioxin analysis. The developed method of solid phase extraction on a dual-layer carbon column requires lower amounts of solvents and sorbents, tolerates high amounts of fat and can be used in both manual and automated sample preparation procedures. The recoveries obtained for the most toxic congeners (2,3,7,8-TCDD, 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF) are within 79-119%.

The content of dioxins and furans in soils, bottom sediments of water bodies, and tissues of small mammals near the landfill site with municipal solid wastes (Moscow, Russia).

For the first time, the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were characterized in the tissues of wild small mammals living in contaminated sites near a municipal solid waste landfill (Moscow, Russia). The Ural field mice Sylvaemus uralensis, the bank voles Clethrionomys glareolus, and the common shrews Sorex araneus were trapped at 1- and 5-km distances from the landfield "Salariyevo." High-resolution chromatography-mass spectrometry was used to measure the levels of 17 PCDD/Fs congeners in the animal organisms and natural objects (soils, bottom sediments). The values of the total toxic equivalencies (WHO-TEQ05) for animals were many times higher than those for soils and bottom sediments. The octo-substituted congeners dominated in the samples from the habitat, whereas the highly toxic 2,3,7,8-substituted ones - in the mammalian tissues. The levels of WHO-TEQ05 were comparable in the soil samples collected at 1- and 5-km distances from the dump body. The levels of WHO-TEQ05 in tissues of mammals caught 1 km from the dump were much higher than those of the distant territory inhabitants. The maximum WHO-TEQ05 levels were found in the shrews, and this has been considered in terms of nutrition characteristics. The data obtained will be used to assess the risks of chronic exposure to low doses of PCDD/Fs contaminating the environment near landfills.

Impact of dioxins on antipyrine metabolism in firefighters.

Antipyrine (AP) metabolism was used to assess factors associated with the activity of hepatic oxidative enzymes in firefighters. Emphasis was placed on 3-hydroxymethylantipyrine (3HMAP), the metabolite with the greatest dependence on dioxin-inducible cytochrome P4501A2 (CYP1A2) activity. AP urinary metabolites were measured by HPLC in 38 male subjects from Eastern Siberia. Subjects were divided into three groups having similar ages and BMIs: current firefighters (n=11); former firefighters (n=17) and non-firefighters (n=10). Multiple regression models were constructed using the three major AP metabolites as a dependent variable to assess the influence of age, smoking as urinary cotinine concentration, dioxin exposure (as either WHO-TEQ or body burden), group, and CYP1A2*F (-163C>A) genotypes. Models for the proportion of dose excreted as the metabolite 3HMAP produced the best fit (adjusted R(2)=0.46, p<0.05). When the models were restricted to current firefighters, only those based on 3HMAP were statistically significant (adjusted R(2) of 0.80 (p<0.002)) due to contributions from urinary cotinine (ß=0.56, p<0.01) and dioxin expressed as body burden (ß=0.55, p=0.014). These results indicate that the antipyrine test can be used as metabolic probe of biological response to recent dioxin exposure provided the impact of smoking is carefully controlled.

Dioxins and cytogenetic status of villagers after 40 years of agent Orange application in Vietnam.

We have examined cytogenetic status of the rural population living on dioxin-contaminated territories (DCT, TCDD in soil 2.6 ng/kg) compared to the villagers of the control area (TCDD in soil 0.18 ng kg(-1)). The examination took place almost 40 years after the war. The consequences of some confounding factors (years of residence in the region, farming, and aging) has been examined. Karyological analysis of buccal and nasal epitheliocytes among healthy adult males living on DCT and control area (26 and 35 persons) was conducted. A wide range of cytogenetic (micronuclei, nuclear protrusions), proliferative (binucleated cells and cells with doubled nucleus) and endpoints of cell death (cells with perinuclear vacuoles, with damaged nucleus membrane, condensed chromatin, pyknosis, karyorrhexis, karyolysis) had been analyzed. The frequent amount of cells with nuclear protrusions in both epithelia was slightly decreased in the DСT group. Biomarkers of early and late stages of nuclear destruction in buccal epithelium (cells with damaged nuclear membrane, karyolysis) were elevated significantly in DCT. Higher level of the same parameters was also identified in nasal epithelium. The cytogenetic status of healthy adult males on DCT had got "normalization" by present moment in comparison with our early data. Nevertheless, in exposed group some alteration of the cytogenetic status was being registered (mostly biomarkers of apoptosis). Years of residence (and exposure to dioxins) affected the cytogenetic status of DCT inhabitants, whereas no influence of farming factors (pesticides, fertilizers, etc.) had been discovered. Some biomarkers of proliferation and cell death were affected by aging.

PCDD, PCDF, and PCB exposure in current and former firefighters from Eastern Siberia.

The current study examines whether the occupation of firefighting contributes to exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs). We compared serum dioxin concentrations and congener profiles of current firefighters (n=13) with those of men who have ceased employment as firefighters (n=17) and with men employed in occupations other than firefighter (n=10). We found that compared to former or non-firefighters, current firefighters have higher levels of dioxins primarily due to the contribution of PCBs and to a lesser extent PCDFs. PCDFs were significantly higher in former firefighters compared to non-firefighters (p<0.05). Comparisons with studies performed by other investigators suggest that local environmental conditions contribute to some of the elevation of PCBs. The congeners 1,2,3,4,6,7,8-heptachlorodibenzodioxin and PCB-114 were significantly higher in current firefighters when compared to former or non-firefighters. Moreover, levels of these congeners were inversely correlated with years since employed as firefighter (Spearman r=-0.610, p=0.009 and Spearman r=-0.53, p=0.03, respectively). The classes of dioxins show an overall decline with years since employed as firefighters, this decline is most evident with PCDDs (Spearman r=-0.46, p=0.06). Together, the combination of evidence supports firefighting as a source of exposure to dioxins.

Temporal trends in serum concentrations of polychlorinated dioxins, furans, and PCBs among adult women living in Chapaevsk, Russia: a longitudinal study from 2000 to 2009.

BACKGROUND: The present study assessed the temporal trend in serum concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls (PCBs) among residents of a Russian town where levels of these chemicals are elevated due to prior industrial activity. METHODS: Two serum samples were collected from eight adult women (in 2000 and 2009), and analyzed with gas chromatography-high-resolution mass spectrometry. RESULTS: The average total toxic equivalency (TEQ) decreased by 30% (from 36 to 25 pg/g lipid), and the average sum of PCB congeners decreased by 19% (from 291 to 211 ng/g lipid). Total TEQs decreased for seven of the eight women, and the sum of PCBs decreased for six of eight women. During this nine year period, larger decreases in serum TEQs and PCBs were found in women with greater increases in body mass index. CONCLUSIONS: This study provides suggestive evidence that average serum concentrations of dioxins, furans, and PCBs are decreasing over time among residents of this town.

Contamination of Russian Baltic fish by polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like biphenyls.

Nineteen species of fish products caught and produced in the Russian economic zone of the Baltic region in 2002-2005 were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like biphenyls (WHO-PCBs). Freshwater fish had significantly lower PCDD/PCDFs levels than most saltwater fish, except cod's fillet for which TEQ was comparable. In some cases pollutant levels of sea fish tissues essentially exceeded current regulatory values. Concentration of WHO(PCDD/F)-TEQ ranged from 0.06 to 0.57pg/g f.w. for freshwater fish, and from 0.16 to 17.83pg/g f.w. for sea fish. The special concern is caused by the high concentration of dioxin-like PCBs, whose contribution to the WHO-TEQ(PCDD/F,PCB) considerably exceeded that of PCDDs and PCDFs. Concentration of WHO(PCB)-TEQ ranged from 2.56 to 124.40pg/g f.w. Profiles of PCDD/Fs congeners in fish were rather similar: in our opinion, the most probable sources of pollution were chlorine bleaching and outflow of PCBs. There is no real reason to assume that fish contamination was affected by the fungicide Ky-5 or similar chlorophenols mixtures. Relative contributions of each dioxin-like PCBs congener to total TEQ in fish tissue are presented in Fig. 2. Profiles of dioxin-like PCBs in general are close to Aroclor 1254, though in some cases there are essential differences.