Distribution Of Polychlorinated Biphenyls Congeners Research Articles

Intracity occurrence and distribution of airborne PCB congeners in Chicago

To evaluate the magnitude and extent of airborne PCBs in an urban area, we measured and investigated the temporal and spatial behavior of atmospheric concentrations of individual polychlorinated biphenyl (PCB) congeners as well as the sum of all congeners (ΣPCB) in both gas and particle phases at 27 locations across the City of Chicago in a single year (2009). In total, 141 gas-phase air samples were collected, including 22 pairs (44 samples) deployed at the same time but at two different locations, and 46 particle-phase samples. ΣPCB in the gas-phase ranged from 80 to 3000 pg/m3, with a geometric mean (GM) of 530 pg/m3, whereas particle-phase ranged from 8 to 160 pg/m3, with a GM of 28 pg/m3. We found the temporal variability to be about three times larger than the variability over space for all gas-phase congeners and ΣPCB. Around 50% of the sample PCB profiles resembled a mixture of a 1:1 vapor Aroclor mixture of 1016 + 1254, with most of the rest (30%) showing enrichment of PCB 3 (>0.1), which did not match any Aroclor profiles. PCB 11 contributed to ~5% in all samples. The fractions of PCB congeners bound to particles ranged from 0.001 to 0.97. Our analysis shows that airborne PCBs are widely distributed across Chicago and confirms that most locations have a similar PCB distribution, but differ in the concentration levels. Volatilization continues to be the main release process of PCBs into the atmosphere, including both Aroclor and non-Aroclor congeners.

Advancing Kinetic Modeling for Polychlorinated Biphenyl (PCB) Mixtures Relevant to Human Exposures: A Case Study Applying the Keyword Analysis Tool to PCBs Congener-Specific Half-Lives

Toxicity resulting from human exposure to PCBs is highly dependent on the absorption, distribution, metabolism, and excretion (ADME) properties of individual PCB congeners. A database of half-life of elimination values for individual congeners was assembled to advance the development of a comprehensive kinetic model for PCB mixtures relevant to human exposures. A novel strategy was employed to identify relevant literature. First, a literature search was conducted using keywords related to PCBs; this generated a database of 58,915 studies. Next, the Keyword Analysis Tool (KAT) was applied to select studies related to PCB congener-specific half-lives across mammalian species. KAT is a software tool designed to increase efficiency in literature screening; it allows users to calculate metrics on the utility of each keyword. By applying keywords related to half-life, elimination, and clearance, KAT identified 5,956 potentially relevant studies from the PCB literature database. A text analytics approach was implemented to further select studies for data extraction. Specifically, sentences from the full text of each study that harbored a keyword were reviewed in conjunction with titles and abstracts to ascertain study relevance. This effort identified 312 studies, 98 of which contained half-life values for 95 PCB congeners across mammalian species. Data from 33 studies identified half-life values for 36 PCB congeners in humans across lifestages, biological matrices, and exposure routes. A retrospective analysis of the KAT search results showed that of 64 keywords used, only 28 were associated with relevant studies, and only 24 keywords would have captured all relevant studies. Additionally, by including keywords relevant to ecological studies, KAT successfully helped prioritize other studies more likely to be relevant to PCB elimination in mammalian species. Thus, KAT identified a highly effective keyword set that can be applied to increase efficiency of future literature searches for chemical half-lives of PCB elimination in humans.

Temporal trends, sources, and relationships between sediment characteristics and polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment cores from the major Seine estuary tributary, France

Temporal trends in polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were reconstructed from sediment cores collected in the Martot and Les Damps ponds, downstream of the Eure River watershed. PAHs exhibited a positive correlation with fine fractions, but mainly with the refractory organic carbon measured in the sediments, which suggests PAH inputs from materials largely composed of refractory carbon (e.g. soot). Since around the 1940s, PAH concentrations ranged between 2.93–38.20 and 2.27–28.20 mg kg−1 in sediment cores from the Martot and Les Damps ponds, respectively. Based on the temporal distribution of isomers and diagnostic ratios, the PAHs in the sediments were found to be predominantly of pyrogenic origin, particularly in the 1940s–1960s, when PAH levels were particularly high. PCBs also showed an affinity with the fine fraction and with refractory organic carbon, albeit less so than PAHs. Since around the 1940s, PCB concentrations ranged between 0.02–1.57 in Martot Pond and 0.09–1.60 mg kg−1 in Les Damps Pond. The recorded PCB temporal trends were mainly associated with the production, consumption, and banning of these chemicals in France. According to the temporal distribution of PCB congeners, high levels in the 1950s–1970s were linked to “technical mixture” discharges into waterways, which were mainly composed of “low chlorinated congeners”, whereas PCB levels after the 1970s were of atmospheric origin.

Polychlorinated Biphenyls in Food.

We measured the concentrations of 205 polychlorinated biphenyl (PCB) congeners in 26 food items: beef steak, butter, canned tuna, catfish, cheese, eggs, french fries, fried chicken, ground beef, ground pork, hamburger, hot dog, ice cream, liver, luncheon meat, margarine, meat-free dinner, milk, pizza, poultry, salmon, sausage, shrimp, sliced ham, tilapia, and vegetable oil. Using Diet History Questionnaire II, we calculated the PCB dietary exposure in mothers and children participating in the AESOP Study in East Chicago, Indiana, and Columbus Junction, Iowa. Salmon had the highest concentration followed by canned tuna, but fish is a minor contributor to exposure. Other animal proteins are more important sources of PCB dietary exposure in this study population. Despite the inclusion of few congeners and food types in previous studies, we found evidence of a decline in PCB concentrations over the last 20 years. We also found strong associations of PCB congener distributions with Aroclors in most foods and found manufacturing byproduct PCBs, including PCB11, in tilapia and catfish. The reduction in PCB levels in food indicates that dietary exposure is comparable to PCB inhalation exposures reported for the same study population.

Can Tenax Extraction Be Used as a Surrogate Exposure Metric for Laboratory-Based Bioaccumulation Tests Using Marine Sediments?

The Tenax technique was used as an alternative exposure metric to assess the bioavailability of polychlorinated biphenyls (PCBs) from contaminated marine sediments. The sediments used were collected from 2 Superfund sites, New Bedford Harbor (MA, USA) and Gould Island (RI, USA). No sieving was conducted for either sediment after arrival, and sediments were stored in stainless steel drums at 2.8 to 4.0 °C in the dark until use. Exhaustive chemical extractions, single-point 24-h Tenax extractions, and 14-d bioaccumulation tests using the amphipod Leptocheirus plumulosus were conducted for both sediments. The sum of 119 PCB congeners from total exhaustive chemical extraction in the New Bedford Harbor and Gould Island sediments were 1084 and 188.2 µg/g organic carbon, respectively. The PCB concentrations from the bioaccumulation tests and Tenax extractions showed that both exposure metrics followed a similar trend in amount and distribution of PCB congeners. The results from both exposure metrics were fit into a log-log linear regression, and then compared with a previously developed log-log linear model for freshwater organisms. The results showed that although the marine data fell within the prediction intervals of the freshwater linear model, the marine regression followed a lower trajectory due to the differences in both the slopes and intercepts between the marine and freshwater regressions. The present study showed a strong relationship between Tenax and marine invertebrate PCB concentrations. Environ Toxicol Chem 2019;38:1188-1197. © 2019 SETAC.

Absence of PCB Hot Spot Effect in Walleye Sander vitreus from Lower Green Bay of Lake Michigan.

Under certain conditions, polychlorinated biphenyl (PCB) concentration in individuals of one sex of an adult fish population may exceed that of the other sex by more than a factor of two. This phenomenon, known as the PCB hot spot effect, has been postulated to be contingent upon the following two conditions: (1) presence of a PCB hot spot in the bottom sediments of the aquatic ecosystem, such that prey PCB concentrations in the hot spot region are substantially higher than prey PCB concentrations in locations distant from the hot spot, and (2) habitat use varying between the sexes, such that individuals of one sex inhabit the hot spot region to a considerably greater degree than individuals of the other sex. To test whether PCB concentrations in walleye Sander vitreus from lower Green Bay of Lake Michigan displayed a PCB hot spot effect, whole-fish PCB concentrations were determined in ten female and ten male adult walleye from the population spawning in the Fox River, the main tributary to lower Green Bay. In addition, mark-recapture data for the Fox River walleye population were analyzed to determine differences in spatial distributions between the sexes. Results revealed that the ratio of mean PCB concentration in males to mean PCB concentration in females was only 1.13, indicating the absence of a PCB hot spot effect. This result was corroborated by the mark-recapture data analysis, which showed no significant difference in habitat use between the sexes. Thus, although condition 1 was met, condition 2 was not met. Consequently, the PCB hot spot effect was not observed in the Fox River walleye population. Lack of a significant difference in PCB congener distributions between the sexes further corroborated our conclusions.

Genetic differences in the aryl hydrocarbon receptor and CYP1A2 affect sensitivity to developmental polychlorinated biphenyl exposure in mice: relevance to studies of human neurological disorders.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that remain a human health concern with newly discovered sources of contamination and ongoing bioaccumulation and biomagnification. Children exposed during early brain development are at highest risk of neurological deficits, but highly exposed adults reportedly have an increased risk of Parkinson's disease. Our previous studies found allelic differences in the aryl hydrocarbon receptor and cytochrome P450 1A2 (CYP1A2) affect sensitivity to developmental PCB exposure, resulting in cognitive deficits and motor dysfunction. High-affinity Ahr b Cyp1a2(-/-) mice were most sensitive compared with poor-affinity Ahr d Cyp1a2(-/-) and wild-type Ahr b Cyp1a2(+/+) mice. Our follow-up studies assessed biochemical, histological, and gene expression changes to identify the brain regions and pathways affected. We also measured PCB and metabolite levels in tissues to determine if genotype altered toxicokinetics. We found evidence of AHR-mediated toxicity with reduced thymus and spleen weights and significantly reduced thyroxine at P14 in PCB-exposed pups. In the brain, the greatest changes were seen in the cerebellum where a foliation defect was over-represented in Cyp1a2(-/-) mice. In contrast, we found no difference in tyrosine hydroxylase immunostaining in the striatum. Gene expression patterns varied across the three genotypes, but there was clear evidence of AHR activation. Distribution of parent PCB congeners also varied by genotype with strikingly high levels of PCB 77 in poor-affinity Ahr d Cyp1a2(-/-) while Ahr b Cyp1a2(+/+) mice effectively sequestered coplanar PCBs in the liver. Together, our data suggest that the AHR pathway plays a role in developmental PCB neurotoxicity, but we found little evidence that developmental exposure is a risk factor for Parkinson's disease.

Heavy metal and PCB spatial distribution pattern in sediments within an urban catchment—contribution of historical pollution sources

This work analyzes polychlorinated biphenyl (PCB) and heavy metal contamination in fluvial sediments and soils in an urban catchment, according to the geo-accumulation index and to soil and sediment quality guidelines. The catchment is located in Coimbra, Portugal, being affected by frequent flooding, and its main stream is a tributary to one of the major rivers in Portugal (Mondego). Given the presence of industrial activities over time, some inputs of pollutants are expected, but so far, the legacy of historic pollution in this catchment has not yet been investigated. Twenty-five samples were collected from nine sampling sites at the depths of 0–20, 20–40 and 40–60 cm (to provide a historic perspective) along longitudinal profiles (streamlines) and in soils downstream of pollution sources. These samples were analyzed for six heavy metals (Cu, Cr, Pb, Cd, Zn, Ni), organic carbon, pH and ten PCBs (IUPAC numbers 28, 30, 52, 101, 138, 153, 166, 180, 204, 209). Total PCB concentrations ranged 0.47–5.3 ng g−1 dry weight (dw), and levels increase from the bottom to the top layers, suggesting an increased input over the last 100 years. PCB congener distribution shows the dominance of hexachlorobiphenyls, especially PCB138, suggesting the existence of local sources. PCB levels did not exceed sediment quality levels, placing sediments/soil under class 1 (not contaminated) or class 2 (trace contamination) with respect to PCB. All six metals exceeded the lowest effect level for sediment quality criteria, and three (Cd, Pb and Zn) largely exceeded the clean levels for dredged materials, placing sediments in class 5 (heavily contaminated). Sampling site S1 presented the highest concentrations of Zn, Pb and Cd, and historic vehicle traffic was identified as the most likely source, given the vertical and horizontal profiles. High levels of Pb, Cd and Zn were found in fluvial sediments at some locations of the Loreto catchment, likely from historic traffic sources. This urban area is frequently affected by flooding events and is currently being subject to urban redevelopment. During these events/actions, historic pollutants in the sediments might surface and be redistributed, impacting the downstream ecosystem of the major Mondego River or increasing the risk of exposure of the urban population.

Concentration of polychlorinated biphenyl (PCB) congeners in the muscle of Clarias gariepinus and sediment from inland rivers of southwestern Nigeria and estimated potential human health consequences

ABSTRACTThe distributions of polychlorinated biphenyl (PCB) congeners were determined in sediment and muscle of the African sharptooth catfish (Clarias gariepinus) from the Ogun and Ona rivers, southwest Nigeria. In addition, the effect of PCB congeners on condition factor (CF) and associated human health risk was assessed using muscle levels for a noncarcinogenic hazard quotient (HQ) calculation. Elevated concentrations of high-molecular-weight (HMW) PCB congeners were detected in sediment and fish downstream of discharge points of both rivers. A significant reduction in fish body weight and CF was observed to correlate with high PCB congener concentrations in the Ona River. A principal component (PC) biplot revealed significant site-related PCB congener distribution patterns for HMW PCB in samples from the Ogun River (71.3%), while the Ona River (42.6%) showed significant PCB congener patterns for low-molecular-weight (LMW) congeners. Biota-sediment accumulation factor (BSAF) was higher downstream for both rivers, presenting PCB congener-specific accumulation patterns in the Ona River. Significant decreases in fish body weight, length and CF were observed downstream compared to upstream in the Ona River. The non-carcinogenic HQ of dioxin-like congener 189 downstream in both rivers exceeded the HQ = 1 threshold for children and adults for both the Ogun and Ona rivers. Overall, our results suggest that industrial discharges contribute significantly to PCB inputs into these rivers, with potential for significant health implications for neighboring communities that utilize these rivers for fishing and other domestic purposes.

Ecology, culture, and management of Burbot: an introduction

Burbot Lota lota has many desirable qualities as a study organism and as an indicator species for the quality of freshwater systems in northern latitudes (Stapanian et al., 2010). It is the only truly freshwatermember of the cod family (Gadidae) and one of only two species of freshwater fish that have a circumpolar range (McPhail & Lindsey, 1970; McPhail & Paragamian, 2000). Burbot occupy the widest range of depths of all fishes found in the Laurentian Great Lakes basin (e.g., small streams to at least 300 m inLakeSuperior) (Boyer et al., 1989). Burbot are among the few freshwater fishes known to communicate via vocalizations (Cott, 2013; Cott et al., 2013). Burbot are sensitive to anthropogenic disturbances, particularly dams and increased water temperatures (reviewed by Stapanian et al., 2010). However, nearly extirpated Burbot populations have recovered in some systems without stocking, following improved water quality and decreased predation from invasive species (Stapanian & Madenjian, 2007; Stapanian et al., 2006, 2008, 2010). Although external sexual dimorphism is subtle and seasonal, the testes of Burbot are very large compared with most other fishes (Cott et al., 2013) and Burbot exhibit sexual differences in range (Stapanian et al., 2013a) and uptake of contaminants (Madenjian et al., 2013, 2014; Stapanian et al., 2013b). Burbot have been shown to be ideal organisms for studies of contaminants in freshwater systems, revealing, for example that latitudinal trends in polychlorinated biphenyl congener distributions are more complex than previously thought (Stapanian et al., 2014), and like in ‘‘higher’’ vertebrates, androgen levels may enhance mercury elimination in teleost fish (Madenjian et al., 2015). World-wide, many Burbot populations are threatened, endangered, or have been extirpated (reviewed by Stapanian et al., 2010). Although illegally stocked Burbot have spread in the upper Colorado River system (USA) (Gardunio et al., 2011), the species is often ignored in fish management and conservation programs (McPhail & Paragamian, 2000; Stapanian et al., 2010). This is due in part to its unpopularity as a sport and commercial fish in much of its range, despite studies indicating that Burbot meat is palatable and nutritious (Brannion, 1930; Tack et al., 1947; Staba, 1979; Addis, 1990; Stapanian & Kakuda, 2008 and references therein). Burbot ecology is poorly studied compared with that ofmost freshwater predators inNorthAmerica and Western Europe (McPhail & Paragamian, 2000). Guest editors: Martin A. Stapanian & Christopher A. Myrick / Ecology, Culture, and Management of Burbot

Polychlorinated Biphenyls Contamination of Sludge in India

Polychlorinated Biphenyls (PCBs) exist in all compartments of the ecosystem due to wide industrial applications and production during burning processes. The PCBs congeners were quantified in the industrial, municipal and agricultural wastes of the most industrialized area of the country, Raipur city, India. The concentration of ΣPCBs in the sludge, sewage and agriculture wastes (n = 4) was ranged from 497 - 800 μg/kg with mean value of 634 ± 146 μg/kg. The PCBs congeners detected in the waste materials were ranged from 56 - 85 with mean value of 75 ± 13. The highest number of congeners was quantified in the sludge materials due to the existence of the heavy PCBs. The PCBs congeners were found to decrease vertically due to the adsorption by the geo-media. The distribution, sources and toxicities of PCBs congeners in the waste materials are discussed.

Polychlorinated biphenyl congener distributions in burbot: evidence for a latitude effect.

The authors compared the distributions of the congeners of polychlorinated biphenyls (PCBs) detected in whole-body samples of burbot (Lota lota) from Great Slave Lake and Lake Erie. Total PCB concentrations in Great Slave Lake burbot were about one-sixtieth of the concentrations in Lake Erie burbot. Burbot from Great Slave Lake contained a higher proportion of lower-chlorinated (2-6 chlorines) congeners than did burbot from Lake Erie; the reverse occurred for more highly chlorinated (7-9 chlorines) congeners. Hexachloro congeners, followed by pentachloro congeners, dominated the proportions of total PCBs in burbot from both lakes. There were no differences between sexes in whole-body samples or between gonad and somatic tissues in the proportions of the 39 congeners and 3 sets of coeluters detected in burbot from Great Slave Lake. In contrast, there were distinct sex differences in congener distributions for older burbot from Lake Erie. The results generally supported a prediction of higher proportions of lower-chlorinated PCB homologs in organisms in remote polar areas. However, the latitudinal effect on PCB congener distribution may be more complex than that portrayed in previous studies.

Multivariate relationships between molecular descriptors and isomer distribution patterns of PCBs formed during household waste incineration

The congener-specific concentrations of mono- to deca-chlorinated biphenyls (PC1-10B) in post-combustion zone flue gases from a laboratory-scale fluidized bed reactor were evaluated and correlated with a set of physicochemical properties and chlorine substitution descriptors. The objective was to identify parameters that affect post-combustion zone polychlorinated biphenyl (PCB) formation and interpreting observed correlations by using principal component analysis (PCA), and bidirectional orthogonal projections to latent structures (O2PLS). Both physicochemical variables and chlorine substitution descriptors were shown to have significant effects on the PCB congener distribution; however, the physicochemical descriptors were more influential in all-homologue models, whereas the chlorine substitution descriptors had a greater impact in single-homologue models, which suggests that PCB formation in general may be under thermodynamic control, whereas the distribution of isomers within homologues is more sensitive to chlorine substitution parameters. The EHOMO and ELUMO variables notably influenced both the PCA and the O2PLS models, which indicate that reactivity and polarization in the molecular structures of the PCBs is of importance.

Sexual difference in PCB congener distributions of burbot (Lota lota) from Lake Erie

Concentrations of 86 congeners of polychlorinated biphenyls (PCBs) were determined for 25 adult female and 25 adult male burbot (Lota lota) from Lake Erie. Significant differences in mean proportions of total PCB concentration between males and females ages 14–17 were found for 26 congeners. Males generally had higher mean proportions of hexachloro congeners, whereas females had higher mean proportions of more highly chlorinated congeners. In contrast, only four congeners exhibited differences between males and females ages 6–13 in mean proportions of total PCB. Therefore, the sexual difference in PCB congener distribution widened for older burbot. Males ages 14–17 also had higher proportions of certain hexachloro congeners than the other three demographic groups (males ages 6–13, females ages 6–13, and females ages 14–17) we examined. The reverse was true for more highly chlorinated congeners. The results supported a previous hypothesis that older male burbot spent a substantial amount of time feeding in the vicinity of mouths of rivers with sediment contaminated with PCBs. However, additional studies are needed to clarify and corroborate this apparent “hot spot” effect, such as seasonal movements, spatial distributions, and diet of burbot; and PCB congener distributions of various species of prey fishes captured at various locations throughout the eastern basin of Lake Erie and at different locations in the contaminated rivers.

Exposure to priority organochlorine contaminants in the Italian general population. Part 2

Concentrations of 36 polychlorinated biphenyl (PCB) congeners were measured in serum of 372 Italian residents of general population living in Novafeltria, Pavia, and Milan. Total PCB level differed significantly between these sites (p < 0.0001) with median concentrations of 836.50, 1354.57, and 2062.08 pmol/g lipid, respectively. However, there is no evidence for the difference in distribution of total PCB levels by genders. Total dioxin-like PCBs differed significantly (p < 0.0001) between the sites (median 109.78, 50.88, and 166.99 pmol/g lipid, respectively) and genders of Novafeltria and Pavia (p = 0.011 and 0.009, respectively). PCB 138, 153, 170, and 180 differed significantly between the places of residence (p < 0.0001) with higher values in Milan population. In the overall population, total PCB and PCB 138, 153, 156, 170, and 180 correlated positively with age (correlations range between 0.320 and 0.569, p < 0.0001). In Novafeltria, the correlations ranged between 0.545 and 0.670, and in Pavia, the correlations ranged between 0.516 and 0.666. In Milan, correlations with age range between 0.327 and 0.417 for total PCB and congeners 138, 153, and 180. With an exception of PCB 170, there was no evidence of significant difference in the distribution of most abundant PCB congeners and total PCB across the body mass index categories.

소나무잎을 PAS로 이용하여 지역별 대기 중 PCBs 농도 추정

Objective: This study was carried out in order to estimate atmospheric Polychlorinated Biphenyls (PCBs) concentrations using pine needles as a passive air sampler (PAS) in urban, semi-rural and rural regions. Methods: One-year old pine needles were collected to analyze their PCBs concentrations (Cp, pg/g dry) at the end of December. PCBs concentrations in ambient air (Ca, pg/m 3 ) were calculated with the logKoa-log(Cp/Ca) model. Results: PCBs concentrations in ambient air (Ca) were high in the order of urban, semi-rural and rural regions. The lower-chlorinated PCBs showed a higher concentration in ambient air. However, the distribution of PCBs congeners was similar in all three regions. Correlation between Ca and the population density of the three regions was significant (R 2 =0.9834, p<0.001). Conclusions: It was concluded that although the production and use of PCBs was banned in the1970s, PCBs are currently being produced unintentionally by human activities.

Seasonal and spatial distributions and possible sources of polychlorinated biphenyls in surface sediments of Yangtze Estuary, China

The surface sediment samples taken from 30 sites of the Yangtze Estuary in both the flood and dry seasons were analyzed to reveal the spatial and seasonal distributions of polychlorinated biphenyls (PCBs). Samples collected in the flood season showed higher PCB concentrations, larger PCB fluctuations and higher portions of large grain sediments in the inner estuary area compared with those collected in the dry season, indicating significant seasonal variations of PCBs. The effects of the physicochemical characteristics (TOC and grain size) of surface sediments on the distributions of PCBs were also investigated. Masked by various other factors, the TOC contents and sediment grain sizes did not exhibit a strong influence on the distributions of PCBs. Analysis of the PCB homolog and congener distribution patterns revealed a predominant proportion of light PCBs with 2–3 chlorines. According to the PCB homolog profiles and principal component analysis (PCA) of source contributions, non-point sources including atmospheric deposition and surface runoff associated with stormwater were suggested to be the major sources of PCBs in the surface sediments of the Yangtze Estuary.

Assessment of the daily intake of 62 polychlorinated biphenyls from dietary exposure in South Korea

The dietary intake of polychlorinated biphenyls (PCBs) was estimated using the sum of 62 PCB congeners (∑62PCBs), including seven indicator PCBs and 12 dioxin-like PCBs, in the South Korea. In this study, 200 individual food samples belonging to 40 different foodstuffs were investigated to estimate the distribution of PCB congeners in five sampling cities. PCB exposure was estimated using Korean dietary habits as established by the National Health and Nutrition Examination Survey (NHANES). The PCB concentrations in rice, the most frequently consumed food in Korea, was relatively low in whole food samples. The mean PCB levels measured in fish were the highest in this study, but each fish is consumed in relatively small amounts by the general population. Therefore, the daily dietary intake should also be considered with regard to human exposure to PCBs, especially with the consumption of contaminated foods. Dioxin-like PCB levels were also calculated using TEF values that were established in 2005. The average levels (pg TEQ/g) were 0.0002 for rice and 0.0098 for fish. The dioxin-like PCBs accounted for a relatively small percentage of the total PCBs, compared to previous studies. According to our research, the health risks associated with exposure to PCBs could be estimated using the tolerable daily intake (TDI) of the general population.

Spatial distribution of chlordanes and PCB congeners in soil in Cedar Rapids, Iowa, USA

Residential soils from Cedar Rapids, Iowa, USA were collected and analyzed for chlordanes and polychlorinated biphenyls (PCBs). This study is one of the very few urban soil investigations in the USA. The chlordanes concentrations ranged from 0 to 7500 ng g −1 dry weight (d.w.), with a mean and standard deviation of 130 ± 920 ng g −1 d.w., which is about 1000 times larger than background levels. ΣPCB concentrations ranged from 3 to 1200 ng g −1 d.w., with a mean and standard deviation of 56 ± 160 ng g −1 d.w. and are about 10 times higher than world-wide background levels. Both groups exhibit considerable variability in chemical patterns and site-to-site concentrations. Although no measurements of dioxins were carried out, the potential toxicity due to the 12 dioxin-like PCBs found in the soil is in the same order of magnitude of the provisional threshold recommended by USEPA to perform soil remediation.

The uptake of persistent organic pollutants by plants

Abstract In a field experiment, the transfer of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from contaminated soil to maize (Zea mays L.), sunflower (Helianthus annuus), poplar (Populus nigra × P. maximowiczii) and willow (Salix × smithiana) and the distribution of PCB congeners in maize and sunflower was investigated. The former waste incinerator in Hradec Králové (Czech Republic) was chosen for the experiment. Results of plot screening showed heterogenous contamination by PCBs and PAHs. PCB soil contamination was evidently caused by Delor 106 or Aroclor 1260 stocking and PAH contamination by chemicals containing fluoranthene, benzo/b/fluoranthene, phenanthrene and pyrene. Tested plants were planted on a contaminated field site, in soil contaminated with 1530 µg/kg of total PCBs and 0.138 and 3.42 mg/kg of total PAHs. The results show that maize and sunflower roots accumulated the most PCBs from soil. These plants accumulated hexa- and heptachlorobiphenyl congeners more than tri-, tetra-, and pentachlorobiphenyl congeners. Total concentrations of PAHs in tested plants ranged from 0.096 to 1.34 mg/kg. The highest phenanthrene concentration was found in aboveground biomass of sunflower and the highest concentration of pyrene, in maize roots.