Non-dioxin-like Polychlorinated Biphenyls Research Articles

Germany's first Total Diet Study - Occurrence of non-dioxin-like polychlorinated biphenyls and polybrominated diphenyl ethers in foods

The occurrence of persistent organic pollutants like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in food represents a public health concern. The BfR MEAL Study was initiated to generate a comprehensive data base of occurrence data for chemicals in the most consumed foods in Germany. Non-dioxin-like PCBs (NDL-PCBs) and PBDEs were analysed in 300 foods, purchased and prepared representatively for the eating behaviour of the population in Germany. Highest levels of NDL-PCBs and PBDEs were detected in spiny dogfish, cod liver, herring, and eel. High NDL-PCB and PBDE levels were observed in other oily fish, wild boar meat, sheep liver, and high-fat dairy products. The comparison of food from conventional and organic production revealed higher NDL-PCB values in the food group ‘meat and meat products’ if produced organically. Occurrence data of this study will improve future dietary exposure and risk assessments in Germany.

Non-invasive biomonitoring of infant exposure to environmental organic pollutants in north-western Spain based on hair analysis. Identification of potential sources

Recent years have seen growing interest in hair sample analysis to detect organic pollutants (OPs). This biological matrix can be analysed non-invasively for biomonitoring of OPs over a wide exposure window. Obtaining hair sample amounts that meet the needs of the analytical methodology required for the determination of the POs of interest can be challenging, especially in infants. As a result, studies assessing organic pollutants in infant hair have been very scarce. We quantified levels of about 60 OPs, including persistent organic pollutants (POPs), in 110 hair samples from a patient cohort (60 mothers and 50 infants) from Santiago de Compostela (north-western Spain). For each participant we examined relationship between OP levels and corresponding epidemiological parameters using correlations, principal component analysis (PCA), hierarchical cluster analysis, and Multivariate analysis of variance (MANOVA). For many OPs we observed significant correlations with place of residence, parity, and maternal age, as well as pet ownership. Evaluation of dietary habits showed significant associations between levels some OPs and the consumption of fish, molluscs, and cereal. There were significant associations between chlorpyrifos and deltamethrin levels and infant birth characteristics such as birthweight and head circumference. Relations between OP levels in the hair of mothers and their infants were also examined, revealing common sources of exposure for dioxin-like polychlorinated biphenyls (DLPCBs), non-dioxin-like polychlorinated biphenyls (NDLPCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs). Levels of fluoranthene (F), pyrene (P), endrin, and some PBDEs in maternal hair were significantly correlated with those in infant hair. Our findings identified common sources of exposure to OPs of distinct chemical classes.

A case study of neurodevelopmental risks from combined exposures to lead, methyl-mercury, inorganic arsenic, polychlorinated biphenyls, polybrominated diphenyl ethers and fluoride.

We performed a mixture risk assessment (MRA) case study of dietary exposure to the food contaminants lead, methylmercury, inorganic arsenic (iAs), fluoride, non-dioxin-like polychlorinated biphenyls (NDL-PCBs) and polybrominated diphenyl ethers (PBDEs), all substances associated with declines in cognitive abilities measured as IQ loss. Most of these chemicals are frequently measured in human biomonitoring studies. A component-based, personalised modified reference point index (mRPI) approach, in which we expressed the exposures and potencies of our chosen substances as lead equivalent values, was applied to perform a MRA for dietary exposures. We conducted the assessment for four different age groups (toddlers, children, adolescents, and women aged 18-45 years) in nine European countries. Populations in all countries considered exceeded combined tolerable levels at median exposure levels. NDL-PCBs in fish, other seafood and dairy, lead in grains and fruits, methylmercury in fish and other seafoods, and fluoride in water contributed most to the combined exposure. We identified uncertainties for the likelihood of co-exposure, assessment group membership, endpoint-specific reference values (ESRVs) based on epidemiological (lead, methylmercury, iAs, fluoride and NDL-PCBs) and animal data (PBDE), and exposure data. Those uncertainties lead to a complex pattern of under- and overestimations, which would require probabilistic modelling based on expert knowledge elicitation for integration of the identified uncertainties into an overall uncertainty estimate. In addition, the identified uncertainties could be used to refine future MRA for cognitive decline.

Analysis of polychlorinated biphenyls (PCBs) in dairy products by modified QuEChERS/GC-QqQ-MS/MS method: A risk assessment study.

Polychlorinated biphenyls (PCBs) are harmful chemicals that are persistent in the environment and can accumulate in the food chain. The purpose of the present research was to assess non-dioxin-like polychlorinated biphenyls (NDL-PCBs) in some dairy products (yogurt, doogh, and kashk) using modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique and gas chromatography-triple-quadrupole mass spectrometry (GC-QqQ-MS/MS) method and risk assessment study. The LOQs (limit of quantifications), LODs (limit of detections), recovery, and RSD for the PCB analytes were 0.180-0.360, 0.06-0.12 ng/g fat, 97.45-102.63%, and 6.33-8.86%, respectively. The results revealed that the mean concentrations of Ʃ6-NDL-PCBs in samples were 15.17 ± 3.44 ng/g fat, which was lower than the standard level established by European Union (EU, 40 ng/g fat). The maximum mean level was PCB 180 (9.98± 2.04 ng/g fat) and the minimum mean level of PCBs in samples was PCB 28 (0.09± 0.06 ng/g fat). Also, results showed that kashk samples had a maximum mean level of 6-NDL-PCBs (18.66 ± 2.42 ng/g fat) and doogh samples had a minimum mean level of 6-NDL-PCBs (12.21 ± 2.22 ng/g fat). The mean level of 6-NDL-PCBs in yogurt samples was 14.65 ± 2.02 ng/g fat. The heat map results showed the correlation between the spectral indices of 6-NDL-PCBs in different dairy products. According to the Monte Carlo method, risk assessment was done using calculating the Estimated Daily Intake (EDI) and Incremental Life Cancer Risk (ILCR). The EDI values of 6 NDL-PCBs based on the 95th percentile in yogurt, doogh, and kashk were 14.3, 1.49, and 0.5ng/kg.day, respectively. Considering that the contaminant level in the samples is lower than the EU limit, it can be concluded that dietary exposure to 6 NDL-PCBs may not pose a risk to the health of consumers.

Occurrence and congener profiles of dioxins (PCDDs), furans (PCDFs) and polychlorinated biphenyls (PCBs) in ovine and caprine milk samples collected in a very polluted site in Central Italy

Concentrations of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 18 polychlorinated biphenyls (PCBs), including 12 dioxin-like (DL-PCBs) and 6 non-dioxin-like PCBs (NDL-PCBs) were measured in 16 ovine and caprine milk samples collected in the territory of Bussi sul Tirino, central Italy, a Site of National Interest (SNI) due to its high and widespread environmental pollution. All the analyzed samples were compliant with the maximum levels fixed by Commission Regulation (EU) 1259/2011 for the content of PCDD/Fs and the sum of PCDD/Fs and DL-PCBs. In two cases, contamination levels of the sum of PCDD/Fs and DL-PCBs were higher than the action levels fixed by EU Recommendation 663/2014. The statistical analysis, performed by Principal Component Analysis (PCA), revealed that the differences in contamination profiles of the different milk samples were independent of the distance of the farms from the Bussi illegal landfill but likely related to local emission sources influencing the exposure to POPs of studied animals.

Pubertal progression in relation to peripubertal exposure to organochlorine chemicals in a cohort of Russian boys.

Peripubertal concentrations of serum dioxins and polychlorinated biphenyls (PCBs) have demonstrated associations with altered age of pubertal onset and sexual maturity in boys, but associations with pubertal progression have received less attention. The Russian Children's Study is a prospective cohort of 516 boys enrolled in 2003-2005 at age 8 or 9 and followed annually up to 19 years of age. Serum concentrations of dioxin-like toxic equivalents (TEQs), polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and non-dioxin-like PCBs (NDL-PCBs) and whole blood lead levels (BLLs) were quantified from blood samples collected at study entry (age 8-9). Testicular volume (TV) was assessed annually using a Prader orchidometer. Pubertal trajectories were identified by applying Group-Based Trajectory Models (GBTMs) to TV measured from ages 8-19. Associations of peripubertal serum TEQs, PCDDs, PCDFs, and NDL-PCBs with specific progression trajectories were modeled using multinomial logistic regression, adjusting for each boy's birthweight, and for BLL, body mass index and nutritional factors at study entry. Among 489 eligible boys with available exposure measures, we identified three pubertal trajectories using GBTMs: slower (34% of boys), moderate (48%) and faster (18%). Boys with higher peripubertal serum TEQs had higher adjusted odds of being in the moderate versus faster trajectory (adjusted odds ratio (aOR) 1.79, 95% CI 1.01, 3.13) and the slower versus faster trajectory (aOR 1.52, 95% CI 0.82, 2.78) per 1 log unit increase in serum TEQs. Boys with higher peripubertal serum PCDFs had higher adjusted odds of being in the moderate compared to the faster trajectory (aOR 1.92, 95% CI 1.20, 3.03) and of being in the slower versus the faster trajectory (aOR 1.42, 95% CI 0.91, 2.33) per 1 log unit increase. Boys with higher NDL-PCBs had higher adjusted odds of being in the faster trajectory versus the moderate (aOR 2.56, 95% CI 0.91-7.20) or slower (aOR 3.31, 95% CI 1.07, 10.25) trajectory. Boys with higher blood lead levels also had higher adjusted odds of being in the slower trajectory of pubertal progression, compared to either the faster (aOR 1.47, 95% CI 0.89, 2.44) or moderate (aOR 1.20, 95% CI 0.83, 1.75) trajectories, per 1 log unit increase in BLL, although these associations did not attain statistical significance. Boys' peripubertal exposure to dioxins and certain PCBs may alter pubertal progression.

Engine oil from agricultural machinery as a source of PCDD/Fs and PCBs in free-range hens

Free-range hens spend most of their lives outdoors, resulting in their heavy exposure to environmental pollutants such as polychlorinated dibenzo-p-dioxin, dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), and non-dioxin-like polychlorinated biphenyls (NDL-PCBs). We present a case of contamination of free-range eggs that is previously unreported in the literature. The aim of our study was a source investigation after finding a high level of PCDD/Fs in samples of eggs from one of the inspected farms. Samples of hens’ eggs, muscles, and livers and the feeds and soils were analyzed. The results showed that the soil samples taken from the paddock contained high concentrations of PCDD/Fs and DL-PCBs expressed as toxic equivalents (TEQ) (72.9 ± 18.2 pg WHO-TEQ g−1 dry mas (d.m.)) and a high concentration of NDL-PCBs (207 ± 46.9 ng g−1 d.m.). The investigation found that the cause of the soil contamination was oil leaking from the farm’s tractor engine. The oil contained very high concentrations of PCDD/F and DL-PCBs (1013 ± 253 pg WHO-TEQ g−1 oil) and 5644 ng g−1 of NDL-PCBs. The source of the contamination was confirmed by the similarity of the PCDD/F and PCB profiles in the hen eggs and the soil contaminated by engine oil. The dietary intake of toxins resulting from consumption of the eggs is provided. For children, the consumption of contaminated eggs would result in an intake of double the tolerable weekly intake (TWI), while for adults, it would be approx. 60–70% of TWI.

Levels of non-dioxin-like PCBs (NDL-PCBs) in liver of loggerhead turtles (Caretta caretta) from the Tyrrhenian Sea (Southern Italy)

The levels of six non-dioxin-like polychlorinated biphenyls (PCBs 28, 52, 101, 138, 153, and 180) were determined in the liver of 84 loggerhead turtles (Caretta caretta) stranded along the coasts of the Tyrrhenian Sea in Campania Region (Southern Italy), from 2017 to 2021. The average value of the sum (∑6PCBIND) was 28.0 ± 52.2 ng/g (w.w.). The hexachlorobiphenyls PCB 153 and PCB 138 and the heptachlorobiphenyl PCB 180 were the main contributors to the ∑6PCBIND. A weak positive correlation was found between CCL and highly chlorinated PCBs, with adult females having lower PCB concentrations than juvenile females and adult males.This study provides more comprehensive information on the levels of NDL-PCB in Mediterranean loggerhead turtles and sets the basis for assessing anthropogenic impacts on this species.

Concentration and probabilistic health risk of polychlorinated biphenyls in cheese samples collected from Tehran, Iran

This study focused on the measurement of non‐dioxin‐like polychlorinated biphenyls (NDL‐PCBs) in cheese samples (traditional and commercial cheese) by a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method by gas chromatography (GC) coupled with triple‐quadrupole (QqQ) tandem mass spectrometry (MS/MS). The recovery of NDL‐PCBs was in the range of 93.22–109.19%, and relative standard deviation (RSD) was in the range of 4.24–9.04%. Also, the limit of detections (LODs) and the limit of quantifications (LOQs) for the PCB analytes ranged from 0.04 to 0.14 ng/g and 0.120 to 0.420 ng/g respectively. The results showed that the mean level of Ʃ6‐NDL‐PCBs in cheese samples was 9.83 ± 3.12 ng/g and maximum was 18.27 ng/g fat, which was lower than the European Union (EU) standard levels (40 ng/g fat in dairy products). The estimated daily intake of 6 NDL‐PCBs through cheese consumption was lower than the tolerable daily intake. Incremental lifetime cancer risk for children and adults due to six PCBs was 7.03E‐6 and 3.14E‐5, which was lower than the acceptable risk level (10−4).

Simultaneous determination of 35 organochlorine pesticides and polychlorinated biphenyls in the serum of the general population in Wuhan by solid phase extraction-gas chromatography-tandem mass spectrometry

有机氯农药(OCPs)和多氯联苯(PCBs)是两类重要的持久性有机污染物,可在环境介质中长期存在,并通过多种途径进入人体,导致人体的高暴露风险。OCPs和PCBs对人体存在诸多健康危害,精准定量人体内OCPs和PCBs的暴露水平是健康效应评价的关键。该研究基于固相萃取-气相色谱-串联质谱联用技术(SPE-GC-MS/MS)建立了同时检测100 μL血清中35种OCPs和PCBs的分析方法。血清样品经尿素沉淀蛋白后,采用Oasis® HLB小柱净化,正己烷-二氯甲烷混合溶液(1∶1, v/v)洗脱,氮吹近干,正己烷定容,多反应监测(MRM)模式检测,内标法定量分析。结果表明,OCPs和PCBs在0.05~50.0 ng/mL范围内线性关系良好,检出限在1.2~71.4 ng/L之间。35种目标分析物的加标回收率在72.6%~142%之间,相对标准偏差小于25%。利用所建立的方法检测了武汉市普通人群血清样本中OCPs和PCBs的浓度水平,结果表明武汉市普通人群广泛暴露于OCPs和PCBs,且以OCPs为主。有8种OCPs和7种PCBs检出率高于50%,其中p,p'-滴滴伊、p,p'-滴滴滴和甲氧滴滴涕检出率达100%,非类二噁英PCBs是PCBs的主要成分。血清中OCPs浓度随年龄增长呈升高趋势,在60岁以上存在性别差异;不同性别、年龄人群血清中PCBs浓度无统计学差异。该方法样本用量少,操作简便,具有较高的准确度和精密度,适用于环境健康研究中大量人群血清样本中痕量OCPs和PCBs的生物监测。

Dietary intakes of dioxins and polychlorobiphenyls (PCBs) and breast cancer risk in 9 European countries.

Dioxins and polychlorobiphenyls (PCBs) are persistent organic pollutants that have demonstrated endocrine disrupting properties. Several of these chemicals are carcinogenic and positive associations have been suggested with breast cancer risk. In general population, diet represents the main source of exposure. Associations between dietary intake of 17 dioxins and 35 PCBs and breast cancer were evaluated in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort from nine European countries using multivariable Cox regressions. The present study included 318,607 women (mean±SD age: 50.7±9.7) with 13,241 incident invasive breast cancers and a median follow-up of 14.9years (IQR=13.5-16.4). Dietary intake of dioxins and PCBs was assessed combining EPIC food consumption data with food contamination data provided by the European Food Safety Authority. Exposure to dioxins, dioxins+Dioxin-Like-PCBs, Dioxin-Like-PCBs (DL-PCBs), and Non-Dioxin-Like-PCBs (NDL-PCBs) estimated from reported dietary intakes were not associated with breast cancer incidence, with the following hazard ratios (HRs) and 95% confidence intervals for an increment of 1 SD: HRdioxins=1.00 (0.98 to 1.02), HRdioxins+DL-PCB=1.01 (0.98 to 1.03), HRDL-PCB=1.01 (0.98 to 1.03), and HRNDL-PCB=1.01 (0.99 to 1.03). Results remained unchanged when analyzing intakes as quintile groups, as well as when analyses were run separately per country, or separating breast cancer cases based on estrogen receptor status or after further adjustments on main contributing food groups to PCBs and dioxins intake and nutritional factors. This large European prospective study does not support the hypothesis of an association between dietary intake of dioxins and PCBs and breast cancer risk.

Analysis of polychlorinated biphenyls in cream and ice cream using modified QuEChERS extraction and GC‐QqQ‐MS/MS method: A risk assessment study

The concentrations of six non–dioxin‐like polychlorinated biphenyls (NDL‐PCBs) were measured using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) by gas chromatography (GC) coupled with triple‐quadrupole (QqQ) tandem mass spectrometry (MS/MS) method in cream and ice cream offered in Tehran (Iran). The results showed the limits of detection, limit of quantification and recovery for the PCB analytes in the ranges 0.04–0.16, 0.132–0.482 ng/g fat, 5.2–9.2 and 95.5–107.2%, respectively. The results showed the mean concentration of total 6NDL‐PCBs in cream (21.634 ± 2.18 ng/g fat) was higher than that in the ice cream (12.317 ± 1.524 ng/g fat) samples. The estimated daily intake (EDI) was lower than the tolerable daily intake (TDI < 10 ng/kg BW/day). Ultimately, the probabilistic model with Monte Carlo simulation (MCS) revealed the incremental lifetime cancer risk levels (95th) of PCB compounds in ice cream (adults = 1.62E−6 and children = 4.37E−6) and cream (adults = 9.65E−7 and children = 7.57E−6) were lower than the level of acceptable risk (10−4).

Polychlorinated dioxins and dibenzofurans (PCDD/F), polybrominated dioxins and dibenzofurans (PBDD/F), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), and per- and polyfluoroalkyl substances (PFAS) in German breast milk samples (LUPE 8)

Most organic pollutants (POP) are persistent in the environment, accumulate in fatty tissues, and so a transfer through the food chain is probably, thereby causing various health effects. We quantified PCDD/F, PBDD/F, PCB, PBDE, perfluorinated substances, and ADONA in breast milk samples collected in two German federal states and breast milk and blood samples from subjects additionally exposed to PFOA.The median (95th percentile) concentrations were 2.43 (6.58) pgWHO2005TEQ/g l.w. for PCDD/F, 2.45 (4.82) pgWHO2005TEQ/g l.w. for dioxin-like PCB (dl-PCB), and 0.62 (2.69) pgWHO2005TEQ/g l.w. for PBDD/F. The relative contributions of the median values of PCDD/F, dl-PCB, and PBDD/F to the total-TEQ were approximately 41%, 42%, and 11%, respectively. Nondioxin-like PCB (ndl-PCB) concentrations were clearly dominated by the higher chlorinated PCB congeners, with medians of 23.2 ng/g l.w. for PCB 153, 13.9 ng/g l.w. for PCB 138, and 13.0 ng/g l.w. for PCB 180. The sum of the 3 congeners (PCB 138, 153, and 180) were multiplied with 1.64 (total PCB) and showed a median of 82.16 ng/g l.w. and a 95th percentile of 173.3 ng/g l.w.Only PFOA and PFOS could be quantified in 29% and 17% of in total 180 samples with 95th percentiles of 53 ng/l and 33 ng/l, respectively. Milk samples (n = 13) from subjects living on PFOA contaminated sites showed higher levels between 33 and 854 ng/l PFOA (mean: 199 ng/l), whilst PFOS could be quantified only in three samples.The sum of 17 PBDE congeners showed medians (95th percentile) of 1737 pg/g l.w. (22,806 pg/g l.w.), with the highest medians of 422 pg/g l.w. for BDE 209 and 378 pg/g l.w. for BDE 153.Overall, our study confirms the declining contamination level in breast milk during the last decade, but points out the need to further reduce the environmental contamination with persistent substances and subsequently the exposure in childhood.

Metabolomics and lipidomics to identify biomarkers of effect related to exposure to non-dioxin-like polychlorinated biphenyls in pigs

Recent epidemiological studies show that current levels of exposure to polychlorinated biphenyls (PCBs) remain of great concern, as there is still a link between such exposures and the development of chronic environmental diseases. In this sense, most studies have focused on the health effects caused by exposure to dioxin-like PCBs (DL-PCBs), although chemical exposure to non-dioxin-like PCB (NDL-PCB) congeners is more significant. In addition, adverse effects of PCBs have been documented in humans after accidental and massive exposure, but little is known about the effect of chronic exposure to low-dose PCB mixtures. In this work, exposure to Aroclor 1260 (i.e. a commercially available mixture of PCBs consisting primarily of NDL-PCB congeners) in pigs is investigated as new evidence in the risk assessment of NDL-PCBs. This animal model has been selected due to the similarities with human metabolism and to support previous toxicological studies carried out with more frequently used animal models. Dietary exposure doses in the order of few ng/kg body weight (b.w.) per day were applied. As expected, exposure to Aroclor 1260 led to the bioaccumulation of NDL-PCBs in perirenal fat of pigs. Metabolomics and lipidomics have been applied to reveal biomarkers of effect related to Aroclor 1260 exposure, and by extension to NDL-PCB exposure, for 21 days. In the metabolomics analysis, 33 metabolites have been identified (level 1 and 2) as significantly altered by the Aroclor 1260 administration, while in the lipidomics analysis, 39 metabolites were putatively annotated (level 3) and associated with NDL-PCB exposure. These biomarkers are mainly related to the alteration of fatty acid metabolism, glycerophospholipid metabolism and tryptophan-kynurenine pathway.

The associations of prenatal exposure to dioxins and polychlorinated biphenyls with neurodevelopment at 6 Months of age: Multi-pollutant approaches

BackgroundPrenatal exposure to persistent organic pollutants, including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs), and nondioxin-like PCBs (NDL-PCBs), has been hypothesized to have a detrimental impact on neurodevelopment. However, the association of prenatal exposure to a dioxin and PCB mixture with neurodevelopment remains largely inconclusive partly because these chemical levels are correlated. ObjectivesWe aimed to elucidate the association of in utero exposure to a mixture of dioxins and PCBs with neurodevelopment measured at 6 months of age by applying multipollutant methods. MethodsA total of 514 pregnant women were recruited between July 2002 and October 2005 in the Sapporo cohort, Hokkaido Study on Environment and Children's Health. The concentrations of individual dioxin and PCB isomers were assessed in maternal peripheral blood during pregnancy. The mental and psychomotor development of the study participants' infants was evaluated using the Bayley Scales of Infant Development-2nd Edition (n = 259). To determine both the joint and individual associations of prenatal exposure to a dioxin and PCB mixture with infant neurodevelopment, Bayesian kernel machine regression (BKMR) and quantile-based g-computation were employed. ResultsSuggestive inverse associations were observed between in utero exposure to a dioxin and PCB mixture and infant psychomotor development in both the BKMR and quantile g-computation models. In contrast, we found no association of a dioxin and PCB mixture with mental development. When group-specific posterior inclusion probabilities were estimated, BKMR suggested prenatal exposure to mono-ortho PCBs as the more important contributing factors to early psychomotor development compared with the other dioxin or PCB groups. No evidence of nonlinear exposure-outcome relationships or interactions among the chemical mixtures was detected. ConclusionsApplying the two complementary statistical methods for chemical mixture analysis, we demonstrated limited evidence of inverse associations of prenatal exposure to dioxins and PCBs with infant psychomotor development.

Suppression of apoptotic signaling in rat hepatocytes by non-dioxin-like polychlorinated biphenyls depends on the receptors CAR and PXR

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) represent a sub-group of persistent organic pollutants found in food, environmental samples and human and animal tissues. Promotion of pre-neoplastic lesions in rodent liver has been suggested as an indicator for a possible increased risk of liver cancer in humans exposed to NDL-PCBs. In rodent hepatocytes, suppression of DNA damage-triggered apoptosis is a typical mode of action of liver tumor promoters. Here, we report that NDL-PCBs suppress apoptosis in rat hepatocytes treated in culture with an apoptogenic dose of UV light. Suppression became less pronounced when the constitutive androstane receptor (CAR) and/or the pregnane-X-receptor (PXR) where knocked-out using siRNAs, while knocking-out both receptors led to a full reconstitution of apoptosis. In contrast, suppression of apoptosis by the CAR or PXR activators phenobarbital or dexamethasone were CAR- or PXR-specific. Induction and suppression of apoptosis were paralleled by changes in caspase 3/7, 8 and 9 activities. Our findings indicate that NDL-PCBs can suppress UV-induced apoptosis in rat hepatocytes by activating CAR and PXR. It needs further investigation if these mechanisms of action are also of relevance for human liver.

Association of serum peripubertal organochlorine chemical concentrations and blood lead levels with pubertal progression in a cohort of Russian boys

BACKGROUND AND AIM: Dioxins, polychlorinated biphenyls (PCBs) and lead are widespread environmental pollutants. Peripubertal exposure is associated with altered age of pubertal onset and sexual maturity in boys, but its impact on pubertal progression is unknown. METHODS: The Russian Children’s Study is a prospective cohort of 516 boys residing in an industrial city historically contaminated with organochlorine pollutants, who were enrolled in 2003-2005 and followed annually from ages 8-19 years. At enrollment, blood was obtained to quantify serum dioxin-like toxic equivalents (TEQs), non-dioxin-like PCBs (NDL-PCBs) and blood lead levels (BLLs). At enrollment and annually thereafter, we assessed boys' pubertal Tanner stage and testicular volume (TV) via Prader orchidometer. To distinguish subgroups with similar pubertal trajectories, we applied group-based trajectory modeling to TV from ages 8-19 years. We used multinomial logistic regression to model the association of peripubertal serum TEQs, NDL-PCBs and BLL with pubertal progression subgroups. RESULTS:This Russian cohort had lower prevalence of obesity and higher serum organochlorine chemicals relative to other pediatric populations. We identified three pubertal trajectories: slower, moderate and accelerated. Higher peripubertal serum TEQs were associated with decreased odds of being in the accelerated (OR 0.56, 95% CI 0.32-0.99) or slower (OR 0.85, 95% CI 0.53-1.35) trajectories versus the moderate, but with increased odds of being in the slower trajectory versus the accelerated (OR 1.51, 95% CI 0.82, 2.79). However, higher NDL-PCBs were associated with increased odds of being in the accelerated trajectory, versus the moderate (OR 2.56, 95% CI 0.91-7.20) or slower (OR 3.31, 95% CI 1.07, 10.25). Higher BLLs were associated with increased odds of being in the slower trajectory versus the accelerated (OR 1.48, 95% CI 0.89, 2.45) or moderate (OR 1.21, 95% CI 0.83, 1.75). CONCLUSIONS:Boys with higher peripubertal serum dioxins, NDL-PCBs and lead may have either accelerated or slower pubertal progression, depending on the specific exposure. KEYWORDS: Biomarkers of Exposure, Endocrine disrupting chemicals, Children's environmental health, Male, Reproductive outcomes, Modeling

The measurement and health risk assessment of polychlorinated biphenyls in butter samples using the QuEChERS/GC‐MS method

The aim of this study was to evaluate non‐dioxin‐like polychlorinated biphenyls (NDL‐PCBs) and the health risk from butter samples using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) modified method and gas chromatography/mass spectrometry (GC‐MS). A total of 60 traditional and industrial butter samples were collected from the local markets of Tehran, Iran, and were subjected to GC‐MS. The results showed that the mean concentration of total NDL‐PCBs in samples was 21.701 ± 9.02 ng/g fat. The amounts of PCBs in traditional butter samples were higher than in the industrial samples. PCB concentrations in all samples were lower than the European Union standard (40 ng/g fat). The 95th percentile incremental lifetime cancer risk of total NDL‐PCBs for children (1.79E−5) and adults (3.80E−6) was less than the acceptable risk level (10−4).

Perspective on prenatal polychlorinated biphenyl exposure and the development of the progeny nervous system (Review).

The developmental origins of health and disease concept illustrates that exposure in early life to various factors may affect the offspring's long-term susceptibility to disease. During development, the nervous system is sensitive and vulnerable to the environmental insults. Polychlorinated biphenyls (PCBs), which are divided into dioxin-like (DL-PCBs) and non-dioxin-like PCBs (NDL-PCBs), are synthetic persistent environmental endocrine-disrupting chemicals. The toxicological mechanisms of DL-PCBs have been associated with the activation of the aryl hydrocarbon receptor and NDL-PCBs have been associated with ryanodine receptor-mediated calcium ion channels, which affect neuronal migration, promote dendritic growth and alter neuronal connectivity. In addition, PCB accumulation in the placenta destroys the fetal placental unit and affects endocrine function, particularly thyroid hormones and the dopaminergic system, leading to neuroendocrine disorders. However, epidemiological investigations have not achieved a consistent result in different study cohorts. The present review summarizes the epidemiological differences and possible mechanisms of the effects of intrauterine PCB exposure on neurological development.

Resistance to Cyp3a induction by polychlorinated biphenyls, including non-dioxin-like PCB153, in gills of killifish (Fundulus heteroclitus) from New Bedford Harbor

Previous reports suggested that non-dioxin-like (NDL) PCB153 effects on cytochrome P450 3A (Cyp3a) expression in Atlantic killifish (Fundulus heteroclitus) gills differed between F0 generation fish from a PCB site (New Bedford Harbor; NBH) and a reference site (Scorton Creek; SC). Here, we examined effects of PCB153, dioxin-like (DL) PCB126, or a mixture of both, on Cyp3a56 mRNA in killifish generations removed from the wild, without environmental PCB exposures. PCB126 effects in liver and gills differed between populations, as expected. Gill Cyp3a56 was not affected by either congener in NBH F2 generation fish, but was induced by PCB153 in SC F1 fish, with females showing a greater response. PCB153 did not affect Cyp3a56 in liver of either population. Results suggest a heritable resistance to NDL-PCBs in killifish from NBH, in addition to that reported for DL PCBs. Induction of Cyp3a56 in gills may be a biomarker of exposure to NDL PCBs in fish populations that are not resistant to PCBs.