Robert C. Hale

Polybrominated diphenyl ether flame retardants in the North American environment

North America consumes over half of the worlds production of polybrominated diphenyl ether (PBDE) flame retardants. About 98% of global demand for the Penta-BDE mixture, the constituents of which are the most bioaccumulative and environmentally widespread, resides here. However, research on the environmental distribution of PBDEs in North America has lagged behind that in Northern Europe. Examination of available governmentally maintained release data suggests that Deca-BDE use in the US substantially exceeds that in Canada. Penta-BDE use probably follows a similar pattern. PBDE demand in Mexico is uncertain, but is assumed to be comparatively modest. Recent research examining air, water, sediment, sewage sludge and aquatic biota suggests that Penta-BDE constituents are present in geographically disparate locations in the US and Canada. The less brominated congeners have been observed in areas distant from their known use or production, e.g. the Arctic. PBDEs have been detected in low concentrations in North American air, water and sediment, but much higher levels in aquatic biota. Increased burdens as a function of position in the food web have been noted. PBDE concentrations in US and Canadian sewage sludges appear to be at least 10-fold greater than European levels and may be a useful barometer of release. In general, PBDE concentrations in environmental media reported in North America are comparable or exceed those observed elsewhere in the world. In contrast to Europe, environmental burdens are increasing over time here, consistent with the greater consumption of the commercial mixtures. However, data remain relatively scarce. Deca-BDE in the North American environment appears largely restricted to points of release, e.g. urban areas and those where PBDE-containing sewage sludges have been applied. This lack of redistribution is likely due to its extremely low volatility and water solubility. Penta-BDE and Deca-BDE products are used in different applications and this may also be a factor controlling their environmental release.

Potential role of fire retardant-treated polyurethane foam as a source of brominated diphenyl ethers to the US environment

Five tetra- to hexabrominated diphenyl ether (BDE) congeners (BDE-47, -99, -100, -153 and -154) are the most frequently reported in wildlife and humans. The commercial penta-BDE product, used predominantly to flame-retard polyurethane foam, consists primarily of these same congeners. In 1999, North American demand accounted for 98% of the total global penta-market of 8500 metric tons. Frogs, housed with flame retardant-treated polyurethane foam as a dry substrate, accumulated 10,100 microg/kg (wet weight) of the above BDEs. Crickets kept therein as food contained 14,400 microg/kg. The crickets are believed to have browsed directly on the foam and, in turn, were consumed by the frogs. BDE congener composition in all three matrices matched that of the penta-commercial product. Similar congeners were also observed in soil and stream sediments collected near a polyurethane foam manufacturing plant. Summed concentrations of BDE-47, -99 and -100, the dominant congeners observed in these samples, ranged from < 1 to 132 microg/kg (dry weight basis). Sunfish fillets obtained from a nearby, off-site pond contained a total of 624 microg/kg (lipid basis). Sewage treatment plant (STP) sludge exhibited these same congeners at 1370 microg/kg (dry weight). BDE-209, the fully brominated congener predominant in the commercial deca-BDE product, was also present at 1470 microg/kg. While no known polyurethane foam manufacturers discharged to this plant, the distribution pattern of the low brominated congeners in the sludge matched that of the penta-product. After four weeks of exposure to ambient outdoor conditions, the surface of flame-retarded polyurethane foam became brittle and began to disintegrate. Subsequent dispersal of these penta-containing foam fragments may be one mechanism by which these BDEs reach the environment.

A global review of polybrominated diphenyl ether flame retardant contamination in birds

As a consequence of substantial, long-term usage, polybrominated diphenyl ethers (PBDEs) have contaminated humans, wildlife, and abiotic matrices around the world. Although several reports have reviewed PBDE contamination in general, none have focused specifically on birds. Birds have long been recognized as invaluable monitoring species for organohalogen contamination. This review summarizes most available PBDE data in birds and emphasizes several specific aspects, i.e., inter-regional differences in PBDE contamination, the extent of BDE-209 contamination, differences in congener composition patterns between piscivorous and terrestrial-feeding birds, trophic biomagnification and temporal changes in PBDE contamination. A meta-analysis of PBDE congener profiles reveals distinctly different patterns between birds utilizing terrestrial and aquatic food webs. Terrestrial-feeding birds appear to exhibit heightened Deca-BDE contamination. Inter-regional comparisons reveal elevated PBDE burdens in North American aquatic birds compared to those from the rest of the world, likely related to greater Penta-BDE demand there. Examination of North American and Chinese terrestrial birds also exhibited some of the highest BDE-209 concentrations ever reported in wildlife, and suggested that urban environments in general and some commercial activities (e.g., electronic recycling) may increase exposure of wildlife and humans to Deca-BDE. Summaries of temporal trend studies suggest that varying usage histories and regulations have influenced PBDE contamination patterns at different regions. As a consequence of continued usage of Deca-BDE around the world, significant increases in BDE-209 burdens have been observed in both North American and European birds. Examination of both wild and laboratory-exposed birds also indicated potential degradation of BDE-209 to less brominated, but more bioavailable/toxic congeners. Therefore, it would be wise to reduce releases of Deca-BDE, the only PBDE formulation remaining in production, to the environment.

Induced cytochrome P-450 in intestine and liver of spot (Leiostomus xanthurus) from a polycyclic aromatic hydrocarbon contaminated environment

Abstract Levels of total cytochrome P-450, of specific P-450 (determined immunologically with MAb 1-12-3 and referred to as P-450E) and ethoxyresorufin O-deethylase (EROD) were elevated in intestine and liver microsomes of spot (Leiostomus xanthurus) collected from the Elizabeth River, a polycyclic aromatic hydrocarbon (PAH) contaminated tributary of Chesapeake Bay. Fish were collected over a sediment PAH concentration gradient that ranged from 9 to 96 000 μg PAH/kg dry sediment. Intestinal P-450E was near the lower limits of detection in fish collected at the relatively clean sites but was elevated 80- to 100-fold in fish collected from contaminated sites. Intestinal EROD activity exhibited a similar trend. Liver P-450E and associated EROD activity was detectable in all samples and was induced approximately eight-fold at the most heavily contaminated site. Despite the sensitivity of the intestine to PAH inducing agents, intestinal P-450E levels did not correlate well with sediment PAH, whereas liver P-450E did. Instead, the intestinal enzyme was induced to similar and high levels at all contaminated sites. The results suggest that the intestine plays an important role in the absorption and metabolism of dietary PAH and/or other PAH-type inducing agents and that intestinal P-450E may be a useful indicator of exposure to these compounds via the diet.

Coastal and Estuarine Risk Assessment

Overview of Ecological Risk Assessment in Coastal and Estuarine Environments, M.H. Roberts, Jr., M.C. Newman, and R.C. Hale Introduction Application of Risk Assessment in Estuaries Forum Organization European Approaches to Coastal and Estuarine Risk Assessment, M. Crane, N. Sorokin, J. Wheeler, A. Grosso, P. Whitehouse, and D. Morrit Introduction Legislative Procedure in the European Union Principles of Chemical Risk Assessment in the EU Retrospective Risk Assessments Conclusions Acknowledgments Emerging Contaminants of Concern in Coastal and Estuarine Environments, R.C. Hale and M.J. La Guardia Introduction Brominated Fire Retardants Polychlorinated Biphenyls Natural and Synthetic Estrogens Alkylphenol Polyethoxylates and Related Degradation Products Other Pharmaceuticals Non-Pharmaceutical Anti-Microbial Agents Personal Care Products Interactions of Multiple Stressors Conclusions Acknowledgements Enhancing Belief during Causality Assessments: Cognitive Idols or Bayess Theorem? M.C. Newman and D.A. Evans Difficulty in Identifying Causality Bacon=s Idols of the Tribe Idols of the Theater and Certainty Assessing Causality in the Presence of Cognitive and Social Biases Bayesian Methods Can Enhance Belief or Disbelief A More Detailed Exploration of Bayes=s Approach Two Applications of the Bayesian Method Conclusion Acknowledgments Bioavailability, Biotransformation and Fate of Organic Contaminants in Estuarine Animals, R.F. Lee Introduction Bioavailability Uptake Fate of Xenobiotics after Uptake by Estuarine Animals Elimination Summary The Bioaccumulation of Mercury, Methylmercury and Other Toxic Elements into Pelagic and Benthic Organisms, R.P. Mason Introduction Bioaccumulation in Pelagic Food Webs Bioaccumulation in Benthis Organisms Membrane Transport Processes Summary Acknowledgments Dietary Metals Exposure and Toxicity to Aquatic Organisms: Implications for Ecological Risk Assessment, C.E. Schlekat, B.-G. Lee, and S.N. Luoma Introduction Current Status of Regulatory Approaches for Metals in Aquatic Systems Processes Affecting Dietary Metal Exposure The Relative Importance of Dietary vs. Dissolved Metal Uptake for Bioaccumulation and Toxicity Toxicological Significace of Dietary Metals Exposure Conclusions/Recommendations Endocrine Disruption in Fishes and Invertebrates: Issues for Saltwater Ecological Risk Assessment, K. Leung, J. Wheeler, D. Morritt, and M. Crane Introduction Effects of Endocrine Disrupting Chemicals on Saltwater Fishes and Invertebrates Developing a Coherent and Cost-Effective Risk Assessment Strategy for Saltwater Endocrine Disrupters Conclusions The Use of Toxicity Reference Values (TRVs) to Assess the Risks Persistent Organochlorines Pose to Marine Mammals, P.D. Jones, K. Kannan, A.L. Blankenship, and J.P. Giesy Overview Introduction Problem Formulation Exposure Assessment Effects Assessment Risk Characterization Conclusions Acknowledgments Effects of Chronic Stress on Wildlife Populations: A Population Modeling Approach and Case Study, D.E. Nacci, T.R. Gleason, R. Gutjahr-Gobell, M. Huber, and W.R. Munns, Jr Introduction Population Matrix Modeling Approach A Stressor of Ecotoxicological Concern A Case Study A Population Modeling Approach and Case Study: Conclusions Acknowledgments References Structuring Population-Based Ecological Risk Assessments in a Dynamic Landscape, C.E. Mackay, J.A. Colton, and G. Bigham Introduction Ecological Risk Assessment Model Population-Based Risk Characterization Discussion Incremental Chemical Risks and Damages in Urban Estuaries: Spatial and Historical Ecosystem Analysis, D.F. Ludwig and T.J. Iannuzzi Introduction Risk and Damage Assessment: Foundations for Urban Ecosystems Conclusions Epilogue - Ecological Risk Assessment in Coastal and Estuarine Environments, M.C. Newman, R.C. Hale, and M.H. Roberts, Jr. Introduction Chapter Contributions to Coastal and Estuarine Risk Assessment Conclusion

Bioavailability of polybrominated diphenyl ether flame retardants in biosolids and spiked sediment to the aquatic oligochaete, Lumbriculus variegatus

Polybrominated diphenyl ether (PBDE) flame retardants have become distributed ubiquitously in the environment. High concentrations have been reported in U.S. sewage sludge (biosolids). The burgeoning practice of land-applying biosolids as fertilizer creates an avenue for reintroduction of PBDEs to surface waters and aquatic sediments. Bioavailability of biosolids- and sediment-associated PBDEs was assessed using the freshwater oligochaete, Lumbriculus variegatus. Oligochaetes were exposed to composted biosolids (1,600 ng/g total PBDEs) and artificial sediment spiked with penta- and deca-brominated diphenyl ether (BDE) formulations (1,300 ng/g total PBDEs). Uptake (28-d exposure) and depuration (21 d) of eight congeners were studied. Polybrominated diphenyl ethers in both substrates were bioavailable, but bioaccumulation was 5 to 10 times greater from spiked artificial sediment. The congeners BDE 47 and BDE 99 were the most prevalent congeners in oligochaetes after exposure. Congener BDE 47 was more bioaccumulative, possibly due to the threefold greater depuration rate of BDE 99. Bioaccumulation of penta- and hexa-brominated congeners appeared to be affected more strongly by substitution pattern than degree of bromination. Uptake of BDE 209, the dominant congener in deca-BDE, was minimal. Accumulation of certain PBDE congeners from biosolids and sediments by benthos provides a pathway for transfer to higher trophic levels, and congener discrimination may increase with each trophic transfer.

Species-specific accumulation of polybrominated diphenyl ether flame retardants in birds of prey from the Chesapeake Bay region, USA

Compared to organochlorines, little is known about polybrominated diphenyl ether (PBDE) contamination of birds of prey breeding in the Chesapeake Bay, the largest estuary in the U.S. This study examined and compared PBDE contamination in eggs of osprey, double-crested cormorant, brown pelican and peregrine falcon from this area. Several legacy persistent organic pollutants such as PCBs and DDE were also investigated. The level of urbanization of the landscape appeared to influence the level of PBDE exposure. PBDE congener distribution patterns varied between piscivorous and terrestrial-feeding birds. This suggests individual congeners may be subject to differences in bioaccumulation, biomagnification or metabolism in the aquatic and terrestrial food webs. Biomagnification of PBDEs was studied in the Bay aquatic food chains for the first time. A biomagnification factor of 25.1 was estimated for SigmaPBDEs for the fish - osprey egg food chain. Hazard quotients, applied as a preliminary evaluation, indicated that PBDEs may pose a moderate hazard to ospreys and peregrine falcons through impairment of reproductive performance.

Flame-Retardants and Other Organohalogens Detected in Sewage Sludge by Electron Capture Negative Ion Mass Spectrometry

Numerous halogenated organic compounds have been identified as pollutants of concern. Those with high persistence and hydrophobicity may concentrate in biota, sediments, and wastewater sludge. Nonetheless, the release to the environment of many remains largely unrecognized. Stabilized sewage sludge (biosolids) is increasingly being land-applied as a soil amendment. However, understanding the risks of land application has been hampered by the compositional complexity of biosolids. Compound specific analytical approaches may also underestimate environmental impact of land application by overlooking additional contaminants. However, utilizing an alternative analytical approach based on compound functional group (i.e., alkyl halides) enhanced the information content of the analysis. To illustrate, 49 organohalogens were observed by gas chromatography with electron capture negative ionization mass spectrometry in sewage sludge; 23 identified as flame-retardants: that is, PBDEs, hexabromocyclododecane, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), 2-ethylhexyl tetrabromophthalate, decabromodiphenyl ethane, 1,2-bis (2,4,6-tribromophenoxy) ethane and Dechlorane Plus. Concentrations ranged from 25 to 1,600,000 ng g(-1) total organic carbon. An additional 16 compounds were tentatively identified as triclosan, chlorinated-methoxy triclosan, chlorinated pesticides, hexachlorobiphenyl, TBB degradation products, brominated furans and nonabromochlorodiphenyl ethers. Such an analytical approach may enhance evaluations of the risks associated with biosolids land-application and assist in prioritizing specific chemicals for future environmental fate and toxicology studies.

Do temporal and geographical patterns of HBCD and PBDE flame retardants in U.S. fish reflect evolving industrial usage

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) are common flame retardants in polymers and textiles. Recognition of the persistent, bioaccumulative, and toxic properties of PBDEs has prompted reductions in their use. In contrast, HBCD has received less scrutiny. The U.S has historically been a dominant BFR consumer. However, the few publications on HBCD in wildlife here suggest modest levels compared to Asian and European studies. In contrast, the HBCD concentrations we detected in U.S. fish are among the highest reported in the world. The temporal trends observed suggest that HBCD use may have risen, and that of Penta-BDE declined, following the 2004 termination of its U.S. manufacture. For example, Hyco River carp collected in 1999-2002 exhibited a mean ∑HBCD (sum of α-, β- and γ-HBCD) concentration of only 13 ng/g (lipid weight basis), but was 4640 ng/g in fish collected in 2006-2007. In contrast, the mean ∑PBDE level in these same fish decreased from 40,700 ng/g in 1999-2002 to 9140 ng/g in 2006-2007. Concentrations of HBCD and PBDEs in several Hyco River fish species exceeded those from rivers less influenced by manufacturing outfalls. Results support the contention that textile-related production, relative to its BFR market share, may release disproportionately large amounts of HBCD to the environment.

Cellular responses and disease expression in oysters (Crassostrea virginica) exposed to suspended field — contaminated sediments

Exposure of oysters to water soluble fractions derived from field-contaminated sediments (FCS) containing predominantly lower molecular weight organic aromatic compounds, has been previously demonstrated to enhance pre-existing infections caused by the protozoan parasite, Perkinsus marinus (Dermo), and the prevalence of experimentally induced infections. To further explore the role of pollution on the onset and progression of disease, effects of suspended FCS from an estuarine creek in Virginia, USA, dominated by higher molecular weight polycyclic aromatic hydrocarbons (PAHs) on cellular responses and Dermo disease expression in oysters (Crassostrea virginica) were examined. Sediments were collected from a PAH polluted estuarine creek in Virginia, USA. To test effects on cellular response, oysters from Maine were exposed daily to 0, 1.0, 1.5, or 2.0 g suspended FCS (corresponding to 0, 70.2, 105, or 140 microg PAHs, respectively) for 5, 10, 20, and 40 days. Hemocyte activities and plasma lipid, protein and lactate dehydrogenase (LDH) levels were then measured. Exposure stimulated neutral red uptake, MTT reduction, and 3H-leucine incorporation in oyster hemocytes at various exposure times, but did not affect the plasma protein, lipid and LDH levels. To test effects on Dermo expression, oysters from a Dermo enzootic area, with an initial estimated infection prevalence of 39%, were exposed daily to 0, 1.0, 1.5, or 2.0 g suspended FCS (corresponding to 0, 75.0, 113, or 150 microg PAHs, respectively) for 30 days. Exposure enhanced disease expression in oysters. However, no significant change was noted in any measured cellular or humoral parameters.