Rapidly growing quantities of e-waste (WEEE) demand the increasing attention of environmental policy all over the world. Developing countries are particularly affected by recycling and disposal activities, which are deemed harmful to health and environment. Holistic or integrated approaches to WEEE policy are required. The paper discusses first recycling technologies for glass from cathode ray tubes (CRT) and printed circuit boards (PCBs) in Vietnam. Thereafter the German approach to WEEE policy is adjusted to allow for an integrated policy. This is then adapted to allow for the recycling of used monitors and computers. / Sự gia tăng một cách nhanh chóng số lượng các chất thải từ các thiết bị điện, điện tử (WEEE) đòi hỏi sự tăng cường chú ý tới các chính sách môi trường toàn cầu. Các nước đang phát triển bị tác động đặc biệt bởi các hoạt động tái chế, do nó ảnh hưởng xấu tới sức khỏe và môi trường. Các phương pháp tổ hợp và toàn diện đối với các chính sách quản lý chất thải điện tử (WEEE) là đòi hỏi cấp thiết. Trong bài báo này, trước hết phân tích đánh giá các công nghệ tái chế thủy tinh đèn hình (thủy tinh CRT) và bản mạch in điện tử (PCBs) ở Việt Nam. Tiếp theo là phương pháp tiếp cận các chính sách quản lý chất thải điện tử của Cộng hòa liên bang Đức được sử dụng để điều chỉnh cho thích hợp nhằm đưa ra giải pháp tổ hợp có thể thích ứng cho việc tái chế màn hình Tivi và máy tính hỏng, hết hạn sử dụng và thải bỏ ở Việt Nam.

This study investigated the concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the particulate and dissolved phase, as well as concentrations of PAHs in the sediment in Kaohsiung Harbor lagoon. Sources of PAHs in the water column were determined by isomer ratios, hierarchical cluster analysis (HCA) and principal components analysis (PCA). The net and annual fluxes of PAHs were calculated after a lagoon-wide water sampling campaign and compared with those found in a previous study (Fang, 2007) in which data from only one water sampling station was used. ¡@¡@In rain season, total PAH concentrations ranged from 21.6 to 36.2 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 15.5 to 27.2 ng/L and from 3.4 to 8.6 ng/L, respectively. In dry season, total PAH concentrations ranged from 13.2 to 31.5 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 8.0 to 21.1 ng/L and from 5.3 to 10.5 ng/L, respectively. Total PAH concentrations were found higher in rain season than in dry season. The highest total PAH concentration in dry season was observed in Chianjen River estuary. Relatively high PAH concentrations were also observed in these southern stations of Kaohsiung Harbor because of their location near Dalin industrial park. Total PAH concentrations ranged from 81.7 to 2279 ng/g for sediment samples, with average of 895 ng/g. The correlations between PAH concentrations and organic carbons, water temperature, salinity and suspended particles were also examined in this study. PAH concentration in dissolved phase was negatively correlated with water temperature (p<0.05). PAH concentration in sediment was positively correlated with organic carbons (p<0.05), and negatively correlated with median diameter (p<0.01). The logKoc¡ÐlogKow relationship in rain and dry season was compared with literature. It was found that the logKoc values were higher than those reported in literature, suggesting that soot particles might play an important role in the transport and distribution of PAHs in the study area. In rain season, PAHs in dissolved phase were mainly from pyrogenic origins; while mainly from petrogenic origins in particulate phase. In contrast, in dry season, PAHs in dissolved phase were mainly from petrogenic origins; while mainly from pyrogenic origins in particulate phase. In addition, it was found, relatively, that petrogenic pollution was introduced maily from the northern area of the lagoon. In rain season, total PCB concentrations ranged from 1.1 to 2.7 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.42 to 2.1 ng/L and from 0.24 to 1.4 ng/L, respectively. In dry season, total PCB concentrations ranged from 0.54 to 1.3 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.20 to 0.74 ng/L and from 0.32 to 0.76 ng/L, respectively. The direction of net fluxes of PAHs in this study are from water to air (net volatilization) in summer. In winter, however, the absorptive PAH fluxes obtained for four to six-ring PAH, such as fluoranthrene, chrysene + triphenylene and benzo[a]anthracene, indicating that PAHs were absorbed into surface waters. According to our results, it was suggested that the results from previous study (Fang, 2007) might underestimate the net fluxes of Pyrene and total fluxes in dry season. The annual fluxes of PAHs estimated in this study were 212 mg/m2 /year and 5.7 kg of PAHs were emitted annually from the harbor lagoon surface waters to the ambient atmosphere.

This study aims to investigate the fate of polychlorinated biphenyls (PCBs) in sediments via using an anaerobic dechlorination model (ADM). PCBs are ubiquitous environmental pollutants, accumulated mostly in aquatic sediments. Significant attention was placed on the anaerobic dechlorination of PCBs since this process leads to the conversion of highly-chlorinated biphenyls to lower chlorinated ones, resulting in less toxic and more biodegradable congeners. An ADM was developed previously for the identification and quantification of anaerobic dechlorination pathways. In the present study, this model was improved and applied to laboratory and environmental sediment PCB data from Baltimore Harbor (BH), Maryland, USA, where PCB contamination has been recorded. The laboratory PCB data was from a 500 day microcosm study conducted with BH sediments which was used to validate the model, as well as to gather information on dominant dechlorination pathways affecting the sediments. ADM predicted the laboratory PCB data almost perfectly and subsequently very well predicted the environmental sediment PCB profiles. A complete identification and quantification of the anaerobic dechlorination pathways occurring in the BH sediments is achieved with this study for the first time. The significant similarity between the sediment sample PCB profiles and the model predicted profiles reveals that the BH sediments have undergone anaerobic dechlorination via a combination of previously identified dechlorination activities (N, P, M) with selective pathways. Model findings are consistent with microbial analysis of the sediments. Better understanding of anaerobic dechlorination mechanisms should aid in predicting natural attenuation of PCBs or developing bioremediation strategies for contaminated sites.

Persistent organic pollutants (POPs) are a threat to the environment and human health because they are ubiquitous, resistant to degradation, can bio-accumulate in organisms and bio-magnify in food chains. They have a detrimental effect on the reproductive, nervous and immunity systems of vertebrates. An international treaty, the Stockholm Convention on POPs, came into force in 2004 and aims to limit and eventually prohibit any use and unintentional production of POPs. South Africa ratified the Convention in 2002. Those compounds currently listed by the Stockholm Convention as POPs include chlorinated pesticides such as dichlorodiphenyltrichlorethane (DDT), chlordane and dieldrin, and industry-related compounds such as polychlorinated biphenyls (PCBs) and hexachlorobenzene. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are also regarded as POPs but - together with some PCBs - they are the unintentional result of anthropogenic activity. This study focussed on the PCDDs, PCDFs and dioxin-like PCBs in the aquatic environment of South Africa particularly because the water resources in this country are under pressure. Despite the fact that South Africa has the sources of these compounds, little is known about the levels of these three groups of compounds. The concentration of twelve dioxin-like PCBs, seven PCDDs and ten PCDFs were determined for 22 sites selected on the grounds of their proximity to possible pollution sources. Analytical determinations included gas chromatography/mass spectrometry and a cell-based bio-assay, the H4IIE-/17C reporter gene assay. Possible sources of the observed pollution were inferred using the following statistical investigative methods: principal component and hierarchical cluster analysis. Seven of the sites had levels higher than the threshold effect concentration of Canada's sediment quality guidelines of 0.85 ngTEQ kg'1 (Toxic Equivalency Quotient). The other sites had lower levels. The highest concentration, 17.8 ng TEQ kg"1, was measured at a site in the southern Gauteng Province. Most of the PCDD/F pollution seemed to have come from combustion sources related to human activity, rather than industrial combustion. Most of the dioxin-like PCB pollution seemed to have been from commercial PCB preparations. Future research would require better characterisation of the sources in order to reduce the formation of these compounds, but also to better understand the exposure and risk scenarios, if humans are to be in close contact with these sources. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2008.

Diseases, such as cardiovascular disease (CVD), are linked to chronic low levels of inflammation. This inflamed state is the product of risk factors including exposure to environmental pollutants, such as polychlorinated biphenyls (PCBs), which are correlated with increased risk for CVD and diabetes. In response to this health risk, our research addresses the mechanisms by which coplanar PCBs elicit an inflammatory response and the mitigation of PCB-induced inflammation through dietary intervention using docosahexaenoic acid (DHA), an omega-3 lipid. Investigators from the University of Kentucky Engineering Department are developing remediation technologies that detoxify PCBs through dechlorination. We studied the cellular toxicity of coplanar PCB 77 remediation products in primary vascular endothelial cells. The dechlorination products elicited different toxicological responses, which were less than the parent compound and contributed to the overall inflammatory response. The presence of PCB 77 at any concentration was sufficient to promote an inflammatory response, which was attenuated with complete dechlorination. PCB 77 is a good model for coplanar PCB-induced toxicity, but in environmental and human samples, coplanar PCB 126 is detected more frequently. Using different doses of PCB 126, we determined that acute exposure to 5 μmol PCB 126/kg mouse was sufficient to produce an inflammatory response without inducing a toxic wasting phenotype. PCB-induced inflammation was attenuated in vitro by DHA-derived neuroprostanes. Applying this information, we fed mice a DHA-enriched diet and exposed them to PCB 126. Liver and adipose lipid profiles confirm an increase in omega-3 fatty acid composition and DHA metabolites, and changes in gene expression indicate a heightened anti-oxidant response in the presence of PCB-induced inflammation. These data provide an overview of the in vivo response to a PCB-induced inflammation after DHA dietary feeding. We have demonstrated that PCB-induced endothelial dysfunction is propagated through lipid domains called caveolae. Caveolae are also signaling domains for toll-like receptor 4 (TLR4), and receptor for lipopolysaccharide (LPS). Similar to PCBs, TLR4 signaling is inhibited by DHA. We compared the caveolae-associated signaling response after exposure to coplanar PCB 126 or LPS. The domain localization of caveolae was altered by both PCB 126 and LPS. Our study determined that PCB 126-induced inflammation was not inhibited by a TLR4-specific inhibitor, but caveolae-based signaling was critical to both PCB 126- and LPS-induced inflammation. Environmental pollutants, such as coplanar PCBs, are risk factors in the development of chronic diseases. Here we investigate possible signaling pathways associated with environmental toxicity and apply potential dietary interventions with omega-3 lipids.

Persistent organic pollutants (POPs) are a threat to the environment and human health because they are ubiquitous, resistant to degradation, can bio-accumulate in organisms and bio-magnify in food chains. They have a detrimental effect on the reproductive, nervous and immunity systems of vertebrates. An international treaty, the Stockholm Convention on POPs, came into force in 2004 and aims to limit and eventually prohibit any use and unintentional production of POPs. South Africa ratified the Convention in 2002. Those compounds currently listed by the Stockholm Convention as POPs include chlorinated pesticides such as dichlorodiphenyltrichlorethane (DDT), chlordane and dieldrin, and industry-related compounds such as polychlorinated biphenyls (PCBs) and hexachlorobenzene. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are also regarded as POPs but - together with some PCBs - they are the unintentional result of anthropogenic activity. This study focussed on the PCDDs, PCDFs and dioxin-like PCBs in the aquatic environment of South Africa particularly because the water resources in this country are under pressure. Despite the fact that South Africa has the sources of these compounds, little is known about the levels of these three groups of compounds. The concentration of twelve dioxin-like PCBs, seven PCDDs and ten PCDFs were determined for 22 sites selected on the grounds of their proximity to possible pollution sources. Analytical determinations included gas chromatography/mass spectrometry and a cell-based bio-assay, the H4IIE-/17C reporter gene assay. Possible sources of the observed pollution were inferred using the following statistical investigative methods: principal component and hierarchical cluster analysis. Seven of the sites had levels higher than the threshold effect concentration of Canada's sediment quality guidelines of 0.85 ngTEQ kg'1 (Toxic Equivalency Quotient). The other sites had lower levels. The highest concentration, 17.8 ng TEQ kg"1, was measured at a site in the southern Gauteng Province. Most of the PCDD/F pollution seemed to have come from combustion sources related to human activity, rather than industrial combustion. Most of the dioxin-like PCB pollution seemed to have been from commercial PCB preparations. Future research would require better characterisation of the sources in order to reduce the formation of these compounds, but also to better understand the exposure and risk scenarios, if humans are to be in close contact with these sources. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2008.

Over the past several decades, there has been growing concern among the public and scientific community regarding adverse health effects resulting from exposure to natural and synthetic compounds that act as endocrine disrupters. The structural similarity of many of these compounds to natural hormones and receptors, as well as their ubiquity in the environment, can result in the potential for interference with the endocrine system of wildlife and humans. Much of the research examining the adverse effects of wildlife exposure to endocrine disrupting chemicals (EDCs) has focused on effects on reproduction or short-term changes in hormone physiology. However, organisms exposed to low levels of EDCs at early life stages could also be susceptible to developmental effects, including neurological and other physiological changes affecting later life stages. In birds, migration can be an important component of the annual life cycle and it can be vulnerable to disruption given that it is under endogenous hormonal and neurological control. Previous studies have shown that developmental exposure of birds to thyroid hormone disruptors, such as polychlorinated biphenyls (PCBs), have resulted in reduced hatching success, lower growth rates, teratogenicity, impaired development, and immunotoxicity. In this thesis, I aimed to supplement what is currently known regarding the effects of developmental exposure to low levels of a mixture of endocrine disrupting chemicals in songbirds, as well as further investigate the latent consequences of such an exposure on migratory life stages. I initially investigated the potential physiological and developmental effects of early exposure to Aroclor 1254, a PCB mixture, in two passerine songbird species: European starlings (Sturnus vulgaris) and red-winged blackbirds (Agelaius phoeniceus) during the critical nestling period. In 2011, European starlings and red-winged blackbirds were orally administered Aroclor 1254 over the period of nestling development, which was repeated in 2012 with only European starlings. For both years, morphological parameters (body mass, tarsus, wing-chord and bill-lengths) were measured daily and plasma thyroid hormones were measured. Additional measurements of wing chord and tarsus length fluctuating asymmetry (FA) were taken in the second year, to further assess contaminant-induced alterations in developmental stability. I found that treatment with environmentally-relevant levels of Aroclor 1254 caused increasing liver residues above the controls but did not result in overt effects on morphological growth parameters during the nestling period in either starlings or red-winged blackbirds. However, we did observe significant differences in 2012 starling’s wing chord FA at day 10 and 13, and tarsus length FA between all treatment groups and controls, indicating the potential for PCB-induced stress. Nestling thyroid hormone profiles (T3) sampled throughout the nestling period supported developmental changes but did not reveal any differences among treatment groups. Starlings were subsequently reared in captivity and further tested during a simulated autumn migration. Migratory activity and orientation were tested using Emlen funnel trials over 6 consecutive weeks. Across treatment groups, we found a significant increase in mass, fat, and feather moult, and decreasing plasma thyroid hormones over time. At 12L:12D, control birds showed a peak in activity and a directional preference for 155.95° (South-southeast), while high-dosed birds did not. High-dosed birds showed a delayed directional preference for 197.48° (South-southwest) under 10L:14D, concomitant with apparent delays in moult. These findings link alterations in avian migratory behaviour to contaminant-specific mechanisms. Exposure to a ubiquitous environmental endocrine disruptor exerted only subtle short-term effects during the period of exposure but importantly, latent effects may be far more relevant for individual fitness. We discuss how the impacts of exposure during early stages of development were not significant for short-term nest success, but can still give rise to longer time-scale effects that are potentially relevant for survival and population stability for migratory birds.

ABSTRACT The tropical and subtropical nearshore marine environments of Queensland, Australia sustain diverse and unique marine wildlife. Continuous population growth and land-use changes along the Queensland coastline are known to exert numerous anthropogenic pressures on these marine ecosystems, including the delivery of high sediment loads. Sediments also provide a transport pathway for persistent organic pollutants (POPs) from rural and urban catchments into the marine environment. While such pollutants are known to be elevated in marine sediment and biota from nearshore areas in Queensland, their input and distribution pathways, as well as exposure and associated risks to wildlife populations are only partially understood. Mounting evidence suggests that POPs may contribute to population declines in marine wildlife species; however, limited information is available regarding the accumulation and effects of these contaminants in endangered or threatened marine turtles. This study aimed to redress some of these information gaps using a case study approach in marine turtle habitats of Moreton Bay, and other embayments in Queensland. Among persistent organic pollutants (POPs), dioxins (polychlorinated dibenzo-p-dioxins; PCDDs) and to some extent also dioxin-like PCBs (polychlorinated biphenyls; PCBs) were found to be widespread and often present at elevated (ppb) levels in surface sediments from Moreton Bay. However, while PCDD/F toxic equivalencies (TEQs) are above international (Canadian) sediment quality guidelines at numerous sites in Moreton Bay, in general TEQs across the Bay are relatively low compared to those from contaminated locations near dense industrial activities. POP contamination in surface sediments across Moreton Bay was investigated by a combination of GIS spatial mapping, geostatistical and traditional statistical modalities. High spatial variability and complex spatial distribution patterns were revealed. High resolution GIS kriging model outputs from the mid to southern Bay facilitated identification of distinct sediment contamination zones, with highest PCB and PCDD/F levels present in nearshore locations, associated with nearby river systems. While primarily governed by organic carbon, a multitude of physical, chemical and hydrological factors were identified to influence the spatial variance of PCDD/F concentrations. The main parameters governing PCDD/F spatial distribution were identified as sediment geochemistry, water depth and anthropogenic alterations of the physical environment and, together, all quantifiable explanatory variables (including hydrodynamic flushing) explained ≈75% of spatial PCDD/F variance. Together, the interaction of these parameters results in complex distribution patterns and highly variable concentrations even among neighbouring sites of 1-3 km resolution. These results suggest that prediction models of POP distributions in the nearshore marine environment may require high-resolution validation, and highlights that the design of low resolution monitoring strategies can have profound impacts on the reliability of contaminant information or any subsequent extrapolations. This knowledge and methodology can be utilised to optimise on-going and future near-shore sediment monitoring programs both locally and in other regions around the world. Using the spatial distributions of dioxin-like contaminants within sediments, this study provided an opportunity to assess field-based relationships between habitat contamination and local marine biota contamination. Detectable levels of PCDD/Fs and dioxin-like PCBs were measured in all green, hawksbill, loggerhead and flatback marine turtle tissues. POP concentrations in sediments were found to significantly correlate with those in the herbivorous green turtle from different sediment contamination zones. These findings demonstrate that sediments represent an important secondary contaminant source and lead to redistribution of POPs to the marine food chain. POP concentrations and TEQs clearly increased from sediment to turtles as well as with increasing trophic levels in marine turtle species. The results from this study demonstrate that the extent of sediment contamination within foraging habitats governs marine turtle exposure, while, trophic status and to some extent age influence contaminant exposure within a particular contamination zone. Despite the relatively low TEQ in sediments from Moreton Bay, TEQ levels in green turtle sub-populations foraging from near-shore locations and higher trophic loggerhead and flatback turtles are similar or elevated compared to those reported for other marine wildlife from Moreton Bay and elsewhere, even compared to higher trophic species from locations impacted by dense industrial activities. High bioaccumulation potential of 2,3,7,8-PCDD/F and dioxin-like PCBs compounds were estimated for green turtles using biota to sediment accumulation factors. Selective accumulation of toxicologically more potent (i.e. lower chlorinated) PCDD/Fs was observed for higher trophic marine turtles, resulting in increasing TEQs for the carnivorous species. Biomagnification was also observed for some non-2,3,7,8-substituted dioxin congeners which typically do not accumulate in most biota. These results are proposed to be due to relatively high accumulation efficiency and/or low metabolic capacity for these POP compounds in marine turtles. These findings are also hypothesised to reflect temperature dependant, greater bioavailability of hydrophobic chemicals in sub-tropical and shallow marine systems. An additional pilot study revealed that in contrast to PCDD/Fs and PCBs, levels of persistent flame retardants (polybrominated diphenyl ethers; PBDEs) were relatively low in marine turtles and other marine species (dugong, fish and shellfish) from Moreton Bay. This suggests relatively low level input of these more recent industrial products into the marine environment. However, as elevated levels of PBDEs have been reported in blood from the general population of Australia, ongoing transport from the terrestrial to the marine system and redistribution of these contaminants, similar to PCDD/F and PCBs, would be expected to occur into the future. Limited information is available regarding the sensitivity of reptiles to and effects of POPs, however, studies have shown that reptiles are sensitive to POPs albeit with uncharacterised relative potency. In the absence of robust toxicological information for reptiles or marine turtles, the potential risks associated with PCDD/F and PCB exposure of Queensland turtle populations was evaluated using toxicity for sensitive biological endpoints observed in mammals and birds. Using probabilistic methodology for marine turtles from Queensland, the body burden of up to 31% and 55% of green and loggerhead turtles, respectively, are above the threshold levels where the most sensitive physiological effects are observed in mammals and birds. While this evaluation illustrates that the contaminants investigated have the potential to impact on the health of marine turtle populations, it must be highlighted that it is compromised by the lack of species-specific (and in this case, class-specific) information, the uncertainty of which is often considered to represent a factor of at least 10. The findings of the present study indicate that exposure to POPs has the potential to adversely affect the health of Queensland’s marine turtle populations, and highlight the need for robust information on reptile specific sensitivity to these compounds.

Polychlorinated-p-dibenzo dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) (collectively termed ‘dioxins’) and polychlorinated biphenyls (PCBs) are three groups of persistent organic pollutants (POPs) ubiquitous in the environment due to their emission from numerous sources, high persistency and a propensity to be transported long distances. These compounds bioaccumulate in animal tissue, biomagnify through the food web and are toxic to humans and wildlife at relatively low concentrations. Humans may be exposed to POPs via ingestion, inhalation and dermal absorption, however, for the general population, approximately 90% of the total exposure occurs through intake of contaminated food particularly from lipid rich products, including seafood. An Australian national study highlighted that, similar to many other countries, seafood contributes a major proportion to dioxin and PCB exposure of Australians. As typical for national studies, the exposure assessment utilised contaminant concentrations in retail (sea)food and consumption information based on national dietary surveys. The risk assessment showed that the Australian population on the whole has a very low risk of exposure to dioxins through food. However, more than 80% of the Australian population lives within 50 km of the coast, where recreational, cultural and/or subsistence fishing of local seafood is prominent, potentially from areas with elevated PCDD/F and PCB concentrations. Through analysis of local seafood contamination and community seafood consumption patterns, this study assessed PCDD/F and PCB exposure for a coastal subpopulation in Moreton Bay, Queensland who consume locally caught seafood from an area with elevated PCDD/F and PCB concentrations but relatively low (background) toxic equivalency (TEQDP) in sediments, which is typical for Australian nearshore marine systems. Despite low sediment TEQDP levels, due to the dominance of octachlorodibenzo-p-dioxin (which is considered less potent compared to the most toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin), elevated TEQDP concentrations were present in local seafood. In particular higher trophic fish species and some traditional seafood were found to contain TEQDP above current EU action and maximum limits. This highlights the efficiency of species specific contaminant uptake, bioaccumulation and biomagnification processes, which can result in accumulation of higher toxic dioxin and PCB congeners in biota. In contrast, concentrations of most organochlorine pesticides and flame retardants (polybrominated diphenylehters (PBDEs)) were relatively low in seafood from Moreton Bay. For fish, uptake of highly lipophilic contaminants, such as PCDD/Fs and PCBs occurs predominantly via food (biomagnification) and respiratory processes (bioconcentration) followed by selective accumulation of the more toxic, lower chlorinated 2,3,7,8 PCDD/F congeners. This study discovered that physical contact with sediment and dermal absorption of lipophilic contaminants also represents an important exposure pathway for sediment dwelling fish, resulting in higher lipid normalised PCDD/F, PCB and TEQ levels (up to 8, 5 and 3 fold) in skin compared to muscle tissue. PCDD/F and PCB congener profiles differed between muscle and skin suggesting biomagnification and skin absorption as the respective predominant uptake pathways for these tissues. Dermal uptake was estimated to contribute up to 46% to the total TEQDP load on a lipid basis in sediment dwelling fish species, thus representing an important exposure pathway, and extending the bioavailability of sediment-sorbed pollutants to the food web. Accurate determinations of lipid content and lipid TEQDP contamination within seafood samples are critical to human exposure assessments. To ensure quality assurance, different seafood extraction methods were tested to evaluate their impact on lipid yields and contaminant concentration. While levels of PCDD/Fs and PCBs on a lipid basis did not vary across the different methods employed in this study, sample preparation is a significant determinant of lipid yield from fattier fish species. If samples were freeze dried prior to extraction, 30% higher TEQDP values (on a wet weight basis) were obtained as compared to extraction using fresh sample material. Such variance in lipid results will have a significant impact on exposure assessments and should be taken into consideration during seafood contaminant analysis. The median TEQDP concentration from local seafood was approximately 25 fold higher compared to the retail seafood analysed for the national Australian risk assessment. The seafood consumption survey results from this study further indicate that coastal subpopulations consume considerably more seafood than the general population (2 to 6 times more in the present case study). This proved to be an important driver for contaminant exposure in this subpopulation. The average monthly dioxin intake for the coastal community ranged between 34 (best case) to 107 (worst case) pg TEQ kg bw-1 month1, (95th percentile: 114 - 362 pg TEQ kg bw-1 month1), an order of magnitude higher than that estimated for the general population. The contaminant exposure via the local seafood consumption pathway alone exceeded WHO tolerable daily intake levels in 11-44% of the population. These results have important implications with respect to adequate contaminant exposure assessments of Australian and other coastal subpopulations. The study outcomes highlight the importance of considering local conditions and information on contaminant fate processes for human exposure evaluations. Local seafood consumption in coastal communities can result in high exposure to PCDD/F and PCBs, even in background contamination areas. This information would be important to consider for developing future sediment quality guidelines and with respect to exposure and associated risks for coastal communities in general.

Despite the importance of muscle in the development of type 2 diabetes, few studies have investigated the effect of polychlorinated biphenyls (PCBs) on muscle energy metabolism. Previous results from our lab suggested that PCB126 exposure induced an indirect negative effect on muscle mitochondrial function. Since PCBs are stored in adipose tissue, we hypothesized that PCB126 alters adipokine secretion which in turn affects muscle metabolism. Objectives. Study the adipose-to-muscle communication in PCB126-induced metabolic defects. Methods. Communication between adipocytes and myotubes was reproduced by exposing C2C12 or mouse primary myotubes to the conditioned medium (CM) of 3T3L1 adipocytes exposed to environmentally relevant PCB126 levels. Results. PCB126 significantly increased adipokine secretion and decreased mitochondrial function, glucose uptake and glycolysis in insulin resistant (IR) but not in insulin sensitive 3T3L1. However, exposure of myotubes to CM of IR 3T3L1 only decreased glucose uptake and insulin sensitivity, without altering myotubes glycolysis or mitochondrial function. Conclusion. Our results suggest that the increased adipokine secretion by adipocytes could explain the decreased muscle glucose uptake and insulin sensitivity when exposed to PCB126.