Concentrations Of PCB Congeners Research Articles

Toxicity and risk evaluation of polychlorinated biphenyls in River Otamiri, Imo State

Polychlorinated biphenyls are a family of dangerous, long-lasting chemicals that can be detrimental to human health and also have a significant propensity to build up in the environment as organic pollutants. In this regard, the toxicity, carcinogenic, and non-carcinogenic health risks of PCBs in the surface water and sediment of the River Otamiri in Imo State were investigated. This study collected surface water and sediment samples from the River Otamiri at four sampling points. An Agilent 7890A gas chromatograph connected to an Agilent 5975C mass selective detector was used to conduct the PCB analysis. Twenty-eight PCB congeners were detected in the water and sediment samples. Also, the PCB congeners’ descriptive statistics (mean and standard deviation) in the studied matrices were reported. The total levels of PCBs in the surface water and sediment ranged from 622.87 − 935.84 ng L−1 and 1621.03 − 2748.17 µg kg−1 respectively. The concentration of PCB congeners in the studied matrices revealed that PCB-118 had the highest concentration, while the lowest concentration was recorded in PCB-157. The toxicity equivalent quotient (TEQ) was used to assess the harmful effect of dioxin-like PCBs in the studied matrices. High TEQs beyond the World Health Organization's (WHO) acceptable limit were observed for PCB-126 and PCB-169 congeners in both surface water and sediments.This raises the possibility of an ecosystem risk. Furthermore, the lifetime cancer risk values of dioxin-like polychlorinated biphenyls (DL-PCBs) in surface water and sediments were within the tolerable risk limit, whereas the hazard quotient values exceeded the recommended tolerable limit stipulated by the WHO. It is critical to notice that PCB-126 contributions had a major impact on the high hazard index values. Additionally, the possibility of non-cancer risks in children is significantly higher than that of adults because of their lower body mass and pickier habits. This indicates that children are more susceptible to the non-carcinogenic effect of DL-PCBs in the studied matrices. In conclusion, awareness programs and environmental policies are required to ensure the safety of the river from organic pollutants.

Patterns in official food control data – Modelling dioxin and PCB profiling data for authentication of Baltic Sea salmon

Fish and fish products are often subjected to food fraud. Due to the significant environmental pollution of the Baltic Sea, fish caught in this area might be labelled as originating from elsewhere. Therefore, analytical proof showing whether fish samples like salmon come from the Baltic Sea or not is of particular interest. Here, official food control data of dioxin and PCB congener concentrations in salmon was used separately and combined as parameters for building one-class classification models using data driven soft independent modelling of class analogy (DD-SIMCA). The training set consisted of Baltic Sea salmon data collected from 2002 through 2019, and the model was tested on Baltic Sea salmon data samples from 2021 and salmon samples coming from China, Chile, Canada, Norway, USA, and Vietnam. The model's performance showed accuracy rates up to 100 %, indicating the model’s future potential to predict whether salmon samples originate from the Baltic Sea or not. This study exemplarily illustrates how the exploration of underlying patterns in official food control data can be used for authentication purposes.

The role of skin biopsy in the detection of exposure to endocrine disrupting chemicals in Mediterranean cetaceans

Use of skin biopsy is proposed as a sensitive non-lethal technique for the hazard assessment of Mediterranean cetaceans exposed to endocrine disrupting chemicals (EDCs). EDCs are a structurally diverse group of compounds that may adversely affect the health of humans and wildlife or their progeny, by interaction with the endocrine system. In the Mediterranean environment top predators accumulate high concentrations of polyhalogenated aromatic hydrocarbons (PHAHs) and toxic metals, incurring high toxicological hazard. In this paper, the hypothesis that Mediterranean cetaceans are potentially at risk due to PHAH-EDCs is investigated using skin biopsy samples. Benzo-a-pyrene monoxigenase (BPMO) activity in skin biopsies was used as a potential indicator of exposure to different organochlorines (OCs) known to have endocrine disrupting properties. The main objective of this paper was to use this non-destructive ecotoxicological tool to define the potential hazard to Mediterranean odontocete and mysicete species, comparing the present data with values detected in other cetaceans from heavily polluted areas, affected by pseudohermaphroditism and other reproductive dysfunction. Subcutaneous tissue consisting of skin and blubber was obtained from striped dolphins (Stenella coeruleoalba), bottlenose dolphins (Tursiops truncatus), common dolphins (Delphinus delphis) and fin whales (Balaenoptera physalus) in the Mediterranean basin. Sampling was performed in the western Ligurian Sea, between Corsica and the French-Italian coast, and in the Ionian Sea. High concentrations of DDT metabolites and PCB congeners (known as Endocrine Disruptors) were detected in the different species. Significant differences in BPMO induction and OC levels were found between odontocetes and mysticetes. Differences in organochlorine bioaccumulation and consequently potential risk due to endocrine disruptors were primarily related to different positions in the marine food web. A statistical correlation was found between BPMO activity and organochlorine (op’DDT, a potent estrogen and antiandrogen and pp’DDE, a potent antiandrogen) levels in skin biopsy specimens of the endangered Mediterranean population of common dolphin. Several conclusions on the potential risk to Mediterranean cetaceans can be drawn from comparison of the levels of OC-EDs detected in Mediterranean odontocetes with those in white whales (Delphinapterus leucas) of the St Lawrence estuary and bowhead whales (Balaena mysticetus) affected by pseudohermaphroditism and other reproductive dysfunction. Finally, these results suggest that BPMO induction may be an early sign of exposure to EDCs such as OCs and a warning of the possibility of transgenerational effects through exposure of future generations via the placenta and milk.

Changes in Polychlorinated Biphenyl Residues in Milk during Lactation: Levels of Contamination, Influencing Factors, and Infant Risk Assessment.

Given the importance of breastfeeding infants, the contamination of human milk is a significant public concern. The aim of this study was to assess the contamination of human milk with dioxin-like PCBs (dl-PCBs) and non-dioxin-like PCBs (ndl-PCBs) in relation to the duration of lactation and other influencing factors, especially the frequency of the consumption of selected foods during pregnancy. Based on this, the health risk to infants was assessed and compared to the tolerable daily intake (TDI). PCB determinations were performed using gas chromatography/mass spectrometry. The ∑ndl-PCB content ranged from 0.008 to 0.897 ng/g w.w., at an average of 0.552 ng/g wet weight, which was 55% of the maximum level according to the EU guidelines for foods for infants and young children. The toxic equivalent (TEQ) was in the range of 0.033-5.67 pg-TEQ/g w.w. The content of non-ortho, mono-ortho, and ndl-PCBs in human milk decreased the longer lactation continued. Moreover, when pregnant women smoked tobacco, this correlated significantly with increases in the concentrations of PCB congeners 156, 118, and 189 in human milk. The human milk contents of PCB congeners 77, 81, 186, 118, and 189 were strongly positively correlated with the amount of fish consumed. The content of stable congeners PCB 135 and PCB 153 increased with age.

Environmental release of non-Aroclor polychlorinated biphenyls by a silicone rubber production site did not lead to elevated plasma levels in the nearby population.

In 2019, high concentrations of the non-Aroclor PCB congeners 47, 51, and 68 were released by a silicone rubber production site in North-Rhine Westphalia, Germany. Local authorities announced a consumption alert for home-grown fruits and vegetables for the affected area which led to a great level of insecurity among the population regarding potential health effects. The aim of study was to determine the plasma levels of the non-Aroclor congeners and the six ndl-indicator congeners (PCB 28, 52, 101, 138, 153, 180) in children and women with child-bearing potential living close to the production site. Altogether n=111 participants, with n=73 female adults and n=38 children were included in this analysis. For the non-Aroclor-PCBs as well as the lower-clorinated ndl-indicator PCBs 28, 52, and 101, the median plasma concentrations were below the LOQ. Only one adult showed an elevated PCB 47 value. In conclusion, no elevated plasma levels could be detected for PCB 47, 51, or 68 in the nearby population of the silicone-rubber production site. However, our study was highly important for risk characterisation as well as risk communication.

Determination of PCB fluxes from Indiana Harbor and Ship Canal using dual-deployed air and water passive samplers

We have developed a method for measuring fluxes of PCBs from natural waters using air and water passive samplers deployed simultaneously in the Indiana Harbor and Ship Canal (IHSC). Net volatilization of ƩPCBs was determined for 2017, and ranged from 1.4 to 2.8 μg m−2 d−1, with a median of 2.0 μg m−2 d−1. We confirm earlier findings that the IHSC experiences constant release of gas-phase PCBs. Gas-phase and freely-dissolved water ƩPCB samples median were 4.0 ng m−3 and 14 ng L−1, both exhibiting increasing concentrations over the year of study, and with a strong positive correlation between them (R2 = 0.93 for ƩPCBs). The relative concentrations of individual PCB congeners were very similar between air and water samples, and resemble Aroclor 1248, a mixture previously reported to contaminate the IHSC sediments. Monthly variability of the volatilization fluxes was primarily driven by the freely-dissolved water concentration changes (R2 = 0.87). Although different sampling methods were performed to estimate air-water fluxes between the month of August of 2006 and 2017, ƩPCB net fluxes have decreased by more than 60%, suggesting that either dredging at IHSC from 2012 to 2017 or reduction of upstream sources have decreased the freely-dissolved water concentrations of PCBs, thus reducing the air-water net volatilization in IHSC. Finally, we have shown that this passive sampling approach represents a simple and cost-effective method to assess the air-water exchange of PCBs, increase analytical sensitivity, enable measurements over time, and reduce uncertainties related to unexpected episodic events.

The spatial distribution of congener-specific human PCB concentrations in a PCB-polluted region

Serum PCB congener concentrations were measured in 602 adults living near a PCB pollution source in eastern Slovakia. We created isoconcentration maps for 21 PCB congeners by geocoding each participant's place of residence and kriging. Concentrations of PCB congeners were inversely associated with the distance of the participants' residence from the source of pollution. Congener-specific risk factors were derived, particularly for PCBs 52 and 153. We observed that the spatial distribution of serum concentrations was influenced by micro-climatic parameters and physicochemical properties of the congeners. PCB congener profiles strongly correlated with that of the PCB commercial product Delor 106, which was manufactured in the region. The isoconcentration maps indicate that the zones with the highest predicted congener concentration have a mean area of approximately 235.75±188.56km2 and the mean enrichment of concentration of congeners in serum in these zones is about 5.12±1.36. We estimate that depending on congener approximately 23,457±18,762 individuals with PCB concentrations exceeding health-based guidance values live in these zones.

The Caryophylladae cestodes, Wenyonia spp Woodland, 1923 Harbours High Quanities of A Specific PCBs Congener in the Fish Host, Synodontis clarias (Linnaeus, 1758), with Histopathological Alterations as Biomarker Response

One hundred and fifty samples of Synodontis clarias were collected,and subjected to parasitologic examination.They were analyzed from three stations of the sampling site (Epe axis of Lekki Lagoon). Out of the total number of specimens examined from the three stations, 56 (37.33%) were infected. The total infected individuals from the three stations had 30 (20.0%) males and 26 (17.33%) females while the non-infected individuals for all the stations had 64 (42.67%) males and females. Also, in this study, Synodontis clarias were infected with two (2) species of parasites the Cestodes (Wenyonia spp) and Nematode (Raphidascaroides spp) which is common among family Mockokidae. The concentration of Polychlorinated biphenyl in the fish tissue, parasite, sediment and water collected from the sampling site were also analyzed . The PCB congeners 8, 18, 28, 44, 77, 81, 123, 153, 156 detected in the water and sediment sample of all the 209 PCB congeners were also reported. The findings presented in the study showed more of the lower chlorinated PCB congeners in the water sample than in the sediment, Synodontis clarias and parasite sample from the three stations in the Epe axis of Lekki Lagoon. The concentration of PCB congeners in the parasite was high in Oribo and Ikosi (549.53 ppb and 569.95ppb) sampling station while it is low in Imode (57.77ppb) station. There was high quantity of PCB 81 found in the parasite but not found in the fish host.The fish samples collected from Oribo had the high concentration of congeners 28, 18, 44, and 52 among other detected, while fish samples collected from station Imode had the high concentration of 44,18,8 and 28 and the fish samples collected from station Ikosi also had the high concentration of PCB 44, 18, 8 and 123 respectively. However, the concentration of PCBs level found in the fish tissue was above W.H.O limits of 200 part per billion (ppb) in Oribo and Ikosi ((607.42ppb and 325.43ppb) sampling station while the concentration was below in Imode (188.61ppb) sampling station and hence the Synodontis clarias in Oribo and Ikosi is not safe and edible for consumption. Laws enacted to protect our Aquatic environment should be enforced.However, the study showed a need for continuous pollution assessment study of aquatic organisms and its environment.

PCB concentrations in plankton size classes, a temporal study in Marseille Bay, Western Mediterranean Sea

PCB levels in plankton were investigated in the Bay of Marseille, Western Mediterranean Sea, between September 2010 and October 2011. Concentrations of PCB congeners (CB 18, CB 52, CB 101, CB 118, CB 138, CB 153, CB 180) were determined in three plankton size-classes (60–200, 200–500 and 500–1000μm) together with different parameters: chlorophyll content, plankton dry-weight biomass, carbon and nitrogen stable isotope ratios and plankton-community structure. The ∑PCB7 concentrations ranged between 14.2 and 88.1ngg−1d.w., for all size classes and all sampling periods. The results do not show the biomass dilution effect and indicate moderate but significant biomagnification with plankton trophic position estimated by δ15N signatures. Equilibrium with water phase may notably contribute in controlling the PCB levels in the plankton. More generally, presented results imply that PCB accumulation in the plankton is an effect of abiotic and trophic complex interactions in the Bay of Marseille.

The influence of perinatal and current dioxin and PCB exposure on reproductive parameters (sex-ratio, menstrual cycle characteristics, endometriosis, semen quality, and prematurity): a review

AbstractPolychlorinated biphenyls (PCBs) and dioxins (PCDDs/Fs) are well-known endocrine disrupters. This paper strives to elucidate the data on reproductive consequences of perinatal dioxin and PCB exposure in men and women. We focused on the following end-points: sex-ratio, endometriosis, menstrual cycle characteristics, sperm quality, and prematurity. We summarize 46 papers and compare their results including effects seen after exposure to background concentrations. Seven of twelve studies showed a decrease in sex-ratio after parental dioxin or PCB exposure. In three of the seven studies, effects were seen after paternal exposure and in three after maternal exposure. In eight of the nine studies on menstrual cycle characteristics, abnormalities were associated with PCB or dioxin exposure, however the results differed. In three studies PCB and TCDD were associated with longer menstrual cycles, while three studies indicated that an increase in PCB/PCDF exposure was associated with shorter cycles. Five studies showed effects on menstrual bleeding with higher PCB or dioxin exposure. A higher rate of irregular menstrual cycles in exposed women was seen in four studies. The conflicting outcomes probably result from variability in study design, timing of exposure and endocrine disrupting properties of the measured congeners. Nine of sixteen studies detected higher PCB or dioxin exposure in women with endometriosis. However, the manner of diagnosing endometriosis and the character of the studies varied from prospective to retrospective. Five of eight studies focusing on sperm quality showed that men, with higher serum concentrations of PCBs and/or PCB congeners and/or PCDFs, had reduced sperm quality, including increased abnormal morphology and reduced motility. The exposure timeframe seemed important here. There are two studies addressing preterm birth in relation to PCBs, one mentioned a shortening of three days of gestational age, two other studies did not find a relation. Recently one study related a shorter gestational age of half a week with overall dioxin activity measured with the CALUX method in cord blood, particularly in boys. In conclusion, exposure to PCBs and dioxins has a negative effect on the reproductive systems of human populations. Although some speculations have been made, the exact mechanism of these effects and the interactions of these compounds with other endocrine disruptors are not yet known. Age at exposure and congener specific properties are probably crucial in interpreting the observed results.

Phytotreatment of Polychlorinated Biphenyls Contaminated Soil by Chromolaena odorata (L) King and Robinson

The ability of Chromolaena odorata propagated by stem cuttings and grown for six weeks in the greenhouse to thrive in soil containing different concentrations of PCB congeners found in Aroclor 1254, and to possibly remediate such soil was studied under greenhouse conditions. Chromolaena odorata plants were transplanted into soil containing 100, 200, and 500 ppm of Aroclor in 1L pots. The experiments were watered daily at 70 % moisture field capacity. Parameters such as fully expanded leaves per plant, shoot length, leaf chlorophyll content as well as root length at harvest were measured. PCB was not phytotoxic to C. odorata growth but plants in the 500 ppm treatment only showed diminished growth at the sixth week. Percentage increases in height of plant were 45.9, 39.4 and 40.0 for 100, 200 and 500 ppm treatments respectively. Such decreases were observed in the leaf numbers, root length and leaf chlorophyll concentration. The control sample showed 48.3 % increase in plant height which was not significant from the treated samples, an indication that C. odorata could survive such PCB concentration and could be used to remediate contaminated soil. Mean total PCB absorbed by C. odorata plant was between 6.40 and 64.60 ppm per kilogram of soil, leading to percentage PCB absorption of 0.03 and 17.03 % per kilogram of contaminated soil. PCBs were found mostly in the root tissues of the plants, and the Bioaccumulation factor were between 0.006-0.38. Total PCB absorbed by the plant increases as the concentration of the compound is increased. With these high BAF ensured, C. odorata could serve as a promising candidate plant in phytoextraction of PCB from a PCB-contaminated soil.

Maternal-to-fetal transfer and concentration profiles of PCB congeners for Steller sea lions (Eumetopias jubatus) from Hokkaido, Japan

The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC–HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. ΣPCBs in the fetuses were 1400±660 (the mean±SD) ng/g-fat in the blubber and 570±320ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r=0.9934, liver: r=0.9160; P≦0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta.

Concentration profiles of PCB congeners in the blubber and liver of Steller sea lions (Eumetopias jubatus) from the coast of Hokkaido, Japan

The concentrations of PCB congeners in the blubber and liver of male and female Steller sea lions (Eumetopias jubatus; SSLs) collected from the Shakotan Peninsula and the Nemuro Strait, Hokkaido, Japan in 2008 and 2010 were measured by HRGC–HRMS, in order to express the concentration profiles in SSLs at these regions. #153 predominated in both organs, followed by #138, #99 and #118. In males, #28 and #31 were concentrated particularly in the blubber, while #177 and #199 were accumulated specifically in the liver. The differences in these concentration profiles might be expressed by the differences in the organs and their functions. The concentrations of #99, #118, #138, #153, and #180 in the blubber appeared to correspond significantly with the differences between genders. The details of the surveys on PCB congeners in SSLs could clarify the differences in the residue levels of individual congeners for organs and genders.

Genetic susceptibility to dioxin-like chemicals’ induction of cytochrome P4501A2 in the human adult linked to specific AhRR polymorphism

BackgroundDioxin-like chemicals are known to exert their effect by binding to aryl hydrocarbon receptor (AhR), forming complexes with aryl hydrocarbon nuclear translocator (ARNT), and binding to dioxin responsive elements (DREs) in promoter region to regulate the transcription of specific genes. In a previous study of the Yucheng cohort of humans who were exposed to high toxic levels of dioxin-like chemicals (PCDFs and PCBs), we reported marked induction of cytochrome P450 1A2 (CYP1A2) activity and this induction was an excellent biomarker of the exposure and adverse human health effects seen in the Yucheng cohort. ObjectivesThe goal of this study was to determine the relationship between inducibility of CYP1A2 and genetic polymorphisms of AhR, ARNT, and AhRR in human. MethodsThe Yucheng victims who completed blood sample collecting in 1994–1995 for serum concentrations of PCB, PCDF, and PCDD congeners, and also completed the caffeine breath tests for CYP1A2 activity were identified. From the collected blood samples, six single nucleotide polymorphisms were selected for genotyping, including AhR (rs2066853), AhRR (rs2292596), ARNT (rs7517566), ARNT (rs3820541), ARNT (rs3768016), and ARNT (rs2228099). ResultsAhRR (rs2292596) polymorphism was significantly related to CYP1A2 inducibility (p=0.01). A linear trend test was observed between people with AhRR (rs2292596) GG, GC, and CC genotype (p=0.0014). ConclusionOverall, AhRR (rs2292596) genotypes predict the inducibility of CYP1A2 in people highly exposed to toxic dioxin-like chemicals. Future studies and analysis will determine to what degree these polymorphisms can predict a human’s susceptibility to dioxin-related adverse human health effects.

Influence of Smoking on Indicatory Congeners Residues Levels in Fish Slices

The aim of this study was do determine changes in concentrations of indicatory PCB congeners (IUPAC numbers: 28, 52, 101, 118, 153, 138, 180) during industrial hot smoking of mackerel (Scomber scombrus L.) and herring (Clupea harengus L.) slices and cold smoking of mackerel slices. PCB content in raw mackerel slices averaged from 1.32±0.29 ng/g wet w. for PCB 52 to 4.66±0.72 ng/g wet w. for PCB 153. In herring slices, PCB content ranged from 1.36±0.25 ng/g wet w. for PCB 28 to 16.50±1.94 ng/g wet w. for PCB 153. During hot smoking, losses of the examined compounds were observed - in herring slices by 15% (PCB 153) to 32% (PCB 52), while in mackerel slices by 3.7% (PCB 80) to 38% (PCB 28). Simultaneously, a slight increase in the content of PCB 180, PCB 118, PCB 153, PCB 138 and PCB 101 occurred during the proper smoking, between 1.5ᵗʰ and 2.5ᵗʰ hour of the smoking process. During cold smoking (26°C, 8 h), PCB concentrations increased significantly (p<0.05) by 26% (PCB 28, PCB 138) to 43% (PCB 180). In the final stage of smoking, PCB content in the alder sawdust and in the smoke had a significant effect on the levels of the analysed PCB congeners in the smoked slices. The main parameter determining the change of these compounds contents was their decrease in co-distillation with steam. In the final phase of the hot smoking a little increase of PCB compounds contents was a consequence of their penetration with smoke to the fish meat tissue.

Serum PCB levels and congener profiles among teachers in PCB-containing schools: a pilot study

BackgroundPCB contamination in the built environment may result from the release of PCBs from building materials. The significance of this contamination as a pathway of human exposure is not well-characterized, however. This research compared the serum PCB concentrations, and congener profiles between 18 teachers in PCB-containing schools and referent populations.MethodsBlood samples from 18 teachers in PCB-containing schools were analyzed for 57 PCB congeners. Serum PCB concentrations and congener patterns were compared between the teachers, to the 2003-4 NHANES (National Health and Nutrition Examination Survey) data, and to data from 358 Greater Boston area men.ResultsTeachers at one school had higher levels of lighter (PCB 6-74) congeners compared to teachers from other schools. PCB congener 47 contributed substantially to these elevated levels. Older teachers (ages 50-64) from all schools had higher total (sum of 33 congeners) serum PCB concentrations than age-comparable NHANES reference values. Comparing the teachers to the referent population of men from the Greater Boston area (all under age 51), no difference in total serum PCB levels was observed between the referents and teachers up to 50 years age. However, the teachers had significantly elevated serum concentrations of lighter congeners (PCB 6-74). This difference was confirmed by comparing the congener-specific ratios between groups, and principal component analysis showed that the relative contribution of lighter congeners differed between the teachers and the referents.ConclusionsThese findings suggest that the teachers in the PCB-containing buildings had higher serum levels of lighter PCB congeners (PCB 6-74) than the referent populations. Examination of the patterns, as well as concentrations of individual PCB congeners in serum is essential to investigating the contributions from potential environmental sources of PCB exposure.

Half-lives of serum PCB congener concentrations in environmentally exposed early adolescents

The aim was to determine half-life of six most abundant PCB congeners in the body of early adolescents. In 304 environmentally exposed children, PCB serum concentration was determined at the age of 8 and 12 years. Half-life was determined for each child assuming exponential decrease or for the whole cohort using multiple regression. Results obtained by both approaches were in agreement. PCB reuptakes corrupting half-life estimates for each child and each congener were evaluated. If one of the serum PCB concentration values fell below the level of detection (LOD) the pair was excluded and if PCB half-life value exceeded the arbitrary value of 30 years. The following median half-lives in years 4.46, 10.59, 9.7, 4.7, 9.1 and 9.8 were obtained for PCB congeners 118, 138 +163, 153, 156 +171, 170 and 180, respectively. The elimination half-life values were not systematically related to PCB serum concentration at any examination age. Between half-life values, percentage of children with significant reuptakes and PCB congener abundance in serum were found significant associations.

Polychlorinated Biphenyl Sorption and Availability in Field-Contaminated Sediments

Traditional and new relationships of polychlorinated biphenyl (PCB) distribution among the solid phases, the free aqueous phase, and biolipids are comprehensively reviewed using seven well-characterized freshwater and marine sediments polluted with PCBs. The traditional relationship relating free aqueous concentration and biolipid concentration to sediment total organic carbon, compound octanol−water partitioning coefficient, and solid-phase contaminant concentration overestimates measured free aqueous concentrations and biolipid concentrations by mean factors of 8 and 33, respectively. By contrast, relationships based on measured free aqueous phase concentrations or the PCB mass fraction desorbed from sediment provide reasonable predictions of biolipid concentrations. Solid-phase concentration-based predictions perform better when sorption to amorphous organic matter and black carbon (BC) is distinguished. Contrary to previously published relationships, BC sorption appears to be linear for free aqueous PCB-congener concentrations in the picogram to microgram per liter range.

Modeling the Global Levels and Distribution of Polychlorinated Biphenyls in Air under a Climate Change Scenario

We used the multimedia chemical fate model BETR Global to evaluate changes in the global distribution of two polychlorinated biphenyls, PCB 28 and PCB 153, under the influence of climate change. This was achieved by defining two climate scenarios based on results from a general circulation model, one scenario representing the last twenty years of the 20th century (20CE scenario) and another representing the global climate under the assumption of strong future greenhouse gas emissions (A2 scenario). The two climate scenarios are defined by four groups of environmental parameters: (1) temperature in the planetary boundary layer and the free atmosphere, (2) wind speeds and directions in the atmosphere, (3) current velocities and directions in the surface mixed layer of the oceans, and (4) rate and geographical pattern of precipitation. As a fifth parameter in our scenarios, we considerthe effect of temperature on primary volatilization emissions of PCBs. Comparison of dynamic model results using environmental parameters from the 20CE scenario against historical long-term monitoring data of concentrations of PCB 28 and PCB 153 in air from 16 different sites shows satisfactory agreement between modeled and measured PCBs concentrations. The 20CE scenario and A2 scenario were compared using steady-state calculations and assuming the same source characteristics of PCBs. Temperature differences between the two scenarios is the dominant factor that determines the difference in PCB concentrations in air. The higher temperatures in the A2 scenario drive increased primary and secondary volatilization emissions of PCBs, and enhance transport from temperate regions to the Arctic. The largest relative increase in concentrations of both PCB congeners in air under the A2 scenario occurs in the high Arctic and the remote Pacific Ocean. Generally, higher wind speeds under the A2 scenario result in more efficient intercontinental transport of PCB 28 and PCB 153 compared to the 20CE scenario. Our modeling indicates that in a future impacted by climate change, we can expectincreased volatilization emissions and increased mobility of persistent organic pollutants with properties similar to those of PCBs.

PCDDs, PCDFs, PCBs, OC pesticides and mercury in fish and osprey eggs from Willamette River, Oregon (1993, 2001 and 2006) with calculated biomagnification factors

The osprey (Pandion haliaetus) population nesting along the main stem Willamette River and lower Santiam River was first studied to evaluate contaminants and reproductive rates in 1993 when 78 occupied nests were present. By 2001, the population increased to 234 occupied nests, a 13.7% annual rate of population increase. A sample egg was collected from each of a series of nests along the Upper River (river mile 55-187) in 1993, 2001 and 2006 to evaluate trends of persistent contaminants (organochlorine [OC] pesticides, polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]). Nearly all OC pesticide residues decreased significantly, e.g., p, p'-DDE (DDE) from 2,350 to 1,353 to 210 microg/kg wet weight (ww). PCBs followed a similar pattern over time, e.g., SigmaPCBs 688 to 245 to 182 microg/kg ww, while PCDDs and PCDFs showed a more precipitous decline (often 85-95%) between 1993 and 2001, with no egg analyses warranted in 2006. During 2001-2002, sample osprey eggs were also collected from nests at three Headwater Reservoirs and two lower reaches (Newberg Pool and Tidal Portland) of the Willamette River, as well as the lower portion of the Santiam River to evaluate spatial residue patterns. Significant differences were seldom detected among the different sampling areas for OC pesticides (probably due to small sample sizes), although higher concentrations were often seen in the lower reaches, e.g., DDE 901 microg/kg ww (Headwater Reservoirs), 1,353 (Upper River), 1,384 (Newberg Pool) and 2,676 (Tidal Portland). PCB congener concentrations in eggs were usually higher in the Tidal Portland reach than at other locations and often significantly higher than at the Headwater Reservoirs or Upper River. Mercury (first analyzed in eggs in 2001), PCDDs and PCDFs were extremely low in 2001/2002 with no significant spatial patterns. Whole fish composite samples of largescale sucker (Catastomus macrocheilus) and northern pikeminnow (Ptychocheilus oregonensis), which account for about 90% of the biomass in the diet of this osprey population, were also collected from the Willamette River in 1993 and 2001 and analyzed for the same contaminants as osprey eggs. Contaminant residues in fish from the Upper River decreased between 1993 and 2001, paralleling findings for osprey eggs. Likewise, spatial patterns for fish residues paralleled findings for osprey eggs from the different reaches in 2001. A second empirical estimate of biomagnification factors (BMFs) from fish to osprey eggs for OC pesticides, PCBs, PCDDs and PCDFs (ww and lipid weight [lw] basis) was calculated based on residue data collected in 2001. The two independent BMF estimates (1993 and 2001) for each contaminant from the Upper River provide a measure of consistency, e.g., DDE (ww) 87 and 79, (lw) 103 and 112; SigmaPCBs (ww) 11 and 8.4, (lw) 13 and 12. Mercury did not biomagnify from fish to osprey eggs (BMF = 0.60). Legacy contaminants investigated had limited (perhaps only DDE), if any, effects on reproductive success of the increasing osprey population nesting along the Willamette River by 2001.