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NON-DIOXIN-LIKE PCBs: EFFECTS AND CONSIDERATION IN ECOLOGICAL RISK ASSESSMENT
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1 NCEA-C-1340 ERASC-003 June 2003 NON-DIOXIN-LIKE PCBs: EFFECTS AND CONSIDERATION IN ECOLOGICAL RISK ASSESSMENT by Tala R. Henry and Michael J. DeVito United States Environmental Protection Agency Experimental Toxicology Division National Health and Environmental Effects Research Laboratory Office of Research and Development Ecological Risk Assessment Support Center Office of Research and Development U.S. Environmental Protection Agency Cincinnati, OH
2 ACKNOWLEDGMENTS This document was prepared by Tala Henry and Michael DeVito of EPA s National Health and Environmental Effects Research Laboratory (NHEERL), Office of Research and Development (ORD) in response to a request received by ORD s Ecological Risk Assessment Support Center (ERASC) from the Ecological Risk Assessment Forum (ERAF). EPA peer review of the document was conducted by Philip Cook, Mike Hornung, and Linda Birnbaum of NHEERL, and Deborah Rice, formerly with ORD s National Center for Environmental Assessment (NCEA). External peer review of the document was conducted by Richard T. DiGiulio of the Nicholas School of the Environment and Earth Sciences, Duke University, North Carolina, and Sean Kennedy, EcoToxicology Consulting, Ontario, Canada. Programmatic review was conducted by the Trichairs of EPA s Ecological Risk Assessment Forum: Susan Roddy, EPA Region 6; Gina Ferreira, EPA Region 2; and Dale Matey, Office of Solid Waste and Emergency Response, Office of Emergency and Remedial Response (OSWER/OERR). Finally, we would like to acknowledge the efforts of Bruce Duncan, EPA Region 10, in initiating the original request. ii
3 TABLE OF CONTENTS Page 1. Introduction Issue Purpose of this Report ERASC Request & Response Chemical Characterization Chemical Structure Nomenclature Physical-Chemical Characteristics Dioxin-Like PCB Congeners Non-Dioxin-Like Congeners Detection, Transport and Disposition of PCBs in the Environment Analytical Methods for Detection of PCBs Fate, Transport and Disposition in the Environment Disposition in the Environment: Media Disposition in the Environment: Biota Biological Effects of Non-Dioxin-Like PCBs Toxicity Pathways Narcosis Liver Effects Endocrine / Neuroendocrine Function Neurochemical / Neurobehavioral Function Immune Function Relative Toxicity of Non-Dioxin-Like vs. Dioxin-Like PCBs Mammals Birds Fish Invertebrates Consideration of Non-Dioxin-Like PCBs in Ecological Risk Assessment Non-Dioxin-Like Effects Endpoints Relative Contribution of Dioxin-Like and Non-Dioxin-Like PCBs Exposure Effects Risk...28 iii
4 6. References APPENDIX 1: Nomenclature & Log K s...45 ow APPENDIX 2: ERASC Request...49 iv
5 1. Introduction 1.1 Issue An estimated one million metric tons of commercial mixtures of polychlorinated biphenyls (PCBs), such as Aroclors (USA), Kanechlors (Japan) and Clophens (Germany), were manufactured (WHO, 1993) and used worldwide as dielectric fluids in capacitors and transformers, heat transfer fluids, hydraulic fluids, lubricating oils, and as additives in pesticides, paints, copy paper, adhesives and plastics during the 1930s through the mid-1970s. PCBs have entered the environment during both use and disposal and have been shown to be ubiquitous contaminants, occurring in most environmental media as well as biota. Historically, analyses of environmental media and associated risk assessments have been conducted using approaches that consider the PCB mixtures as a whole, i.e., Total PCBs or Aroclors. Subsequently, it has been shown that the fate of various congeners in the environment varies, such that the PCB congener profiles in environmental media may change significantly from the original commercial mixtures. Likewise, individual PCB congeners have been found to vary significantly in their uptake, distribution, metabolism, and elimination within biological systems such that the congener profile in biological tissues can be quite different from both the original commercial PCB mixture and environmental media. Toxicological effects and dose-response relationships within biological systems can also vary among the different PCB congeners. As a result, the consensus within the scientific community is that Total PCB - and/or Aroclor-based risk analyses may not adequately characterize risks posed by PCB mixtures (WHO, 2001). Those PCB congeners that elicit dioxin-like toxicity have been defined and a toxicity equivalence approach for use in both human health and ecological risk assessment has been developed (U.S. EPA, 2000, 2001, 2003). However, the dioxin-like PCB congeners represent only 12 of the 209 possible congeners. To assess risks posed by the remaining 197 congeners, information on the fate and effects of the non-dioxin-like congeners is required. 1.2 Purpose of this Report To provide ecological risk assessors with a concise summary of the state-of-thescience regarding the biological effects of non-dioxin-like PCBs. To provide ecological risk assessors with a compilation of references describing the biological effects of non-dioxin-like PCBs. The list of references is comprised primarily of books, reports, and review articles to provide risk assessors with sources from which they may acquire a thorough overview of the topics at hand. These materials should be used as a source for primary literature references. 1
6 1.3 ERASC Request & Response The issues addressed in this report are those specifically requested in the Ecological Risk Assessment Support Center Request Form (Appendix 2). These issues are listed below along with the section(s) of the report where the information addressing each issue can be located. Describe the mode of action of non-dioxin-like compounds and types of effects in receptors (i.e., those congeners that "travel" with the listed dioxins, furans, and PCBs but just don't act via the Ah receptor) Addressed in Section 4. Discuss n-d-l toxicity relative to congener characteristics (something like a QSAR discussion of planes and rings and big chlorines) Addressed in Sections 2 & 4. Discuss which congeners are of greatest concern (potency) for n-d-l toxicity (dose/response type information in the narcotic range of effects) Addressed in Sections 3 & 4. Recommend how this scientific info on action, effects, and toxicity should be used in eco risk assessment where PCBs are present (preferred use of the data, considerations for site-specific application, etc.) Addressed in Section 5. Discuss whether a general narcosis model can or should be used to evaluate n-d-l effects (as a function of range of contaminant concentration typically seen at low, medium, and highly contaminated sites) Addressed in Sections 4 & 5. Provide an interactive video-conference on this topic and the one related to congener analytical methodology This portion of the request requires another process. 2
7 2. Chemical Characterization A brief overview of PCB nomenclature and chemical properties is provided in this section. Several detailed compilations of PCB chemistry and nomenclature have been compiled previously for all PCBs (Erickson, 1997, 2001; ATSDR, 2000) and for nondioxin-like PCBs (Hansen, 1999). 2.1 Chemical Structure Figure 1. Structure PCBs. 2.2 Nomenclature Polychlorinated biphenyls (PCBs) are a class of chemicals characterized by a common biphenyl molecular framework to which 2 to 10 chlorine atoms may be attached (Figure 1). Although technically not polychlorinated, mono-chlorinated biphenyls are generally included when referring to PCBs collectively. Congener - one of 209 possible PCB structures having the formula, C 12 H 10-nCl n, where n = Each of the 209 PCB congeners can be specifically defined by standard chemical nomenclature rules in which the number and position of chlorines on the biphenyl ring(s) are designated. Each PCB congener has also been assigned a number, between 1 and 209, by the International Union of Pure and Applied Chemists (IUPAC). The IUPAC numbers provide a convenient shorthand system, but do not provide information as to the specific chemical identity of the congener. A list of all 209 PCB congeners, including IUPAC name, IUPAC # and CAS # are provided in Appendix 1. Homolog - a subset of PCB congeners defined by the degree of chlorination, i.e., monochlorobiphenyls through decachlorobiphenyls (Table 1). PCBs within a homolog group have the same molecular weight and number of chlorines attached to the biphenyl ring, but the pattern of chlorination varies among the individual isomers within the homolog group. A list of all PCB homolog groups, including IUPAC name and CAS # are provided in Appendix 1. 3
8 Table 1. Chemical Groupings of Polychlorinated Biphenyls Number of Chlorines Homolog Group Molecular Formula Molecular Weight Number of Isomers 0 biphenyl C 12 H mono-cb C 12 H 9 Cl di-cb C 12 H 8 Cl tri-cb C 12 H 7 Cl tetra-cb C 12 H 6 Cl penta-cb C 12 H 5 Cl hexa-cb C 12 H 4 Cl hepta-cb C 12 H 3 Cl octa-cb C 12 H 2 Cl nona-cb C 12 HCl deca-cb C 12 Cl Isomer - biphenyls within the same homolog group (i.e., same molecular weight and molecular formula) with different substitution patterns. Specific isomers are defined by the position(s) of the chlorine atoms on the biphenyl rings (e.g., 3,3',4,4',5- pentachlorobiphenyl). 2.3 Physical-Chemical Characteristics Most pure PCB congeners are colorless, odorless crystals under ambient conditions (Erickson, 2001). Commercial PCB mixtures (e.g. Aroclors) are clear, viscous liquids, with viscosity increasing with degree of chlorination. Generally, PCBs have high boiling points (>200 C), low vapor pressures, low water solubilities (ppm to ppt), moderate to high log K ow s (~4 to 8), high bioconcentration factors (BCFs) and do not degrade readily, which all contribute to their persistence in the environment. These physical-chemical properties may vary widely between the individual congeners. A summary of these properties, presented as averages for homolog group (Erickson, 2001) and for individual congeners (Hansen, 1999), have been compiled. High quality Log K ow values for all 209 PCB congeners, as determined by Hawker and Connell (1988), are provided in Appendix 1 for reference. Primary sources of information on specific congener properties are referenced within these summaries. 4
9 2.4 Dioxin-Like PCB Congeners The 12 PCBs listed in Table 2 act through the aryl hydrocarbon receptor (AHR) to cause the full range of toxic responses elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Hence, these PCB congeners are referred to as the dioxin-like PCBs. The structure-activity relationships underlying the distinction of dioxin-like PCBs from the other PCBs have been characterized. The dioxin-like PCBs have chlorines in a minimum of four of the lateral positions (i.e., 3, 3', 4, 4', 5, 5') and none (non-) or only one (mono-) of the ortho positions (i.e., 2, 2', 6, or 6') of the biphenyl. The PCBs without ortho substituted chlorines are often referred to as co-planar PCBs, but this terminology is not technically appropriate since these PCBs do not easily assume a planar conformation similar to that of the dioxins and furans (WHO, 2001). The non-ortho dioxin-like PCBs (i.e., PCBs 77, 81, 126 & 169) bind the AHR and cause dioxin-like toxicity in fish, birds and mammals. The mono-ortho chlorinated dioxin-like PCBs are also able to bind the AHR and cause dioxin-like toxicity in birds and mammals, but generally do not cause dioxin-like responses in fish. The toxicological effects which may occur, as a result of exposure to dioxin-like PCBs in fish, birds and mammals, have been well characterized relative to the other PCBs. Dioxin-like toxicity in ecological receptors has been summarized in the scientific literature and in numerous EPA reports (Peterson et al., 1993; Walker and Peterson, 1994; Niimi, 1996; Hoffman et al., 1996; Rice et al., 2002; ATSDR, 2000; U.S. EPA, 1993, 1995a,b, 2001) and will not be discussed in detail further in this report. Table 2. Dioxin-Like PCBs IUPAC # Homolog Group Substitution Group IUPAC Name non-ortho substituted PCBs 77 tetra-cb non-ortho 3,3',4,4'-tetra-CB 81 tetra-cb non-ortho 3,4,4',5-tetra-CB 126 penta-cb non-ortho 3,3',4,4',5-penta-CB 169 hexa-cb non-ortho 3,3',4,4',5,5'-hexa-CB mono-ortho substituted PCBs 105 penta-cb mono-ortho 2,3,3',4,4'-penta-CB 114 penta-cb mono-ortho 2,3,4,4',5-penta-CB 118 penta-cb mono-ortho 2,3',4,4',5-penta-CB 123 penta-cb mono-ortho 2,3',4,4',5-penta-CB 156 hexa-cb mono-ortho 2,3,3',4,4',5-hexa-CB 157 hexa-cb mono-ortho 2,3,3',4,4',5'-hexa-CB 167 hexa-cb mono-ortho 2,3',4,4',5,5'-hexa-CB 189 hepta-cb mono-ortho 2,3,3',4,4',5,5'-hepta- 5
10 In ecological risk assessments, the dioxin-like PCBs should be included in a cumulative assessment with all other chemicals that act via the same mechanism of action (i.e., AHR agonists such as polychlorinated dibenzo dioxins (PCDDs) and furans (PCDFs)). Presently, the most credible approach for assessing mixtures of dioxin-like chemicals is to apply a toxicity equivalence approach in which the concentrations of the individual dioxin-like congeners are converted to TCDD toxicity equivalence concentrations (TEC) using a toxicity equivalence factor (TEF) or a relative potency factor (RPF). Guidance for applying the toxicity equivalence approach in ecological risk assessment is currently being prepared by EPA s Risk Assessment Forum (U.S. EPA, 2003). For complementary information on applying the toxicity equivalence approach for assessment of PCDDs, PCDFs and dioxin-like PCBs, see van den Berg et al. (1998) and U.S. EPA (2000, 2001). Certain dioxin-like PCBs may act via multiple toxicity pathways. Hence, while the 12 dioxin-like PCBs are known to cause dioxin-like toxicity via the AHR, the 8 mono-ortho dioxin-like congeners may also act via non-ahr mechanisms to cause additional effects. As other toxic pathways for PCBs are elucidated, it is possible that dioxin-like PCBs may be found to cause adverse effects on additional ecologically-relevant endpoints. At this time, information about the mechanisms of action and dose-response relationships in ecological receptors is insufficient to allow assessment of dioxin-like PCBs on the basis of non-ahr mediated pathways. However, a number of studies of effects of PCB mixtures in wildlife species (including both laboratory and field exposure scenarios) have shown that most, if not all, toxicity caused by the mixtures (e.g. Aroclors) can be attributed to the TCDD equivalence concentration (TEC) of the mixture (Walker et al., 1996; Tillitt et al., 1996; Tillitt and Wright, 1997; Giesy and Kannan, 1998). 2.5 Non-Dioxin-Like Congeners The 197 PCB congeners which were not discussed in the previous section are currently referred to collectively as non-dioxin-like congeners. These congeners are also often referred to as the non-coplanar or ortho-substituted congeners. However, experts attending an international World Health Organization Consultation in 2001 established preference for the biologically-based term non-dioxin-like for several reasons, the most compelling being that even the non-ortho substituted PCBs are not strictly planar in configuration and some ortho-substituted PCB congeners have both dioxin-like and nondioxin-like activity (WHO, 2001). As more research is conducted on these congeners it is likely that they will be classified more specifically into additional subsets based on toxicological effects endpoints (e.g., endocrine active PCBs; neurotoxic PCBs, immunotoxic PCBs; etc.) and/or mechanisms of action (estrogen receptor agonists/antagonists; serotonin biosynthesis inhibitors; etc.). Current knowledge of non- AHR-mediated effects of PCBs are the subject of Part 4 of this report. 6
11 3. Detection, Transport and Disposition of PCBs in the Environment 3.1 Analytical Methods for Detection of PCBs The various congener-specific analytical methods have been reviewed in detail elsewhere; several recent reviews are summarized here. The second edition of a book dedicated to this topic, Analytical Chemistry of PCBs, was published in 1997 (Erickson, 1997). Analytical methods are reviewed more briefly in a recent compilation of papers presented at a PCB workshop held in 2000 (Robertsen and Hansen, 2001). Frame (2001) presents a concise overview of various analytical methods for quantifying PCBs, dedicating most of the text to the ultimate PCB mixture analytical procedure he refers to as Comprehensive, Quantitative, Congener-Specific (CQCS) PCB Analysis. EPA s Method 1668A is highlighted and is predicted to become the gold standard of CQCS PCB analysis. A more pragmatic presentation of congener-specific methods is provided by Beliveau (2001) of EPA s Region 1. Beliveau also provides an examination of Aroclor and partial congener analyses as well as full references for the various EPA methods for analysis of PCBs in various environmental matrices. Hansen (1999) has compiled important details to consider in interpreting and presenting congener-specific data. U.S. EPA Region 9's Biological Technical Assistance Group has also reviewed various analytical methods for routine congener-specific analysis and report that methods currently available are adequate and cost-effective (Valoppi et al., 1999). This report also presents a phased approach for PCB congener-specific analysis specifically for use within the context of performing site-specific ecological risk assessments. As European and U.S. regulatory agencies move away from Total PCB and Aroclor analyses, it has been recognized that analysis of all possible PCB congeners may not be necessary, possible or practical on a routine basis (WHO, 2001). The analysis of subsets of PCB indicator-congeners, selected based on abundance, prevalence and distribution in the environment, has been proposed as an approach for hazard identification, estimating exposure, and prioritizing risk assessment activities (WHO, 2001). It should be noted that the WHO expert panel did not support the use of indicator congeners for measures of toxicity however, due to the limited data available on the effects of nondioxin-like congeners (WHO, 2001). Hence, while it has been recognized that a full 209 congener-specific analysis may not be necessary for all phases or tiers of risk assessment and efforts are underway to identify subsets of congeners to measure for particular applications (e.g. hazard identification, screening, remedial monitoring, etc.), characterization of the relative contribution of non-dioxin-like PCB congeners to PCB mixture toxicity remains a significant data gap. Several different lists of potential indicator congeners have emerged from various sources (WHO, 2001; Frame, 2001; Valoppi et al., 1999; NOAA, 1993; McFarland and Clarke, 1989). To date, EPA has not established a definitive list of indicator congeners, standardized an approach for analyzing PCBs nor has any of EPA s programs promulgated a congener-specific method (Beliveau, 2001). 7
12 3.2 Fate, Transport and Disposition in the Environment Historically (1930s-1970s), commercial mixtures of PCBs were used worldwide as dielectric fluids in capacitors and transformers, heat transfer fluids, hydraulic fluids, lubricating oils, and additives in pesticides, paints, copy paper, adhesives and plastics (ATSDR, 2000; Hansen, 1999). PCBs have been released into the environment as a consequence of historical use and disposal; releases of newly manufactured PCBs having been stopped within the U.S. since banning of the manufacture and use of PCBs in commerce in the 1970s. Examples of primary sources include landfills, hazardous waste sites, incineration of PCB-containing wastes, leakage from old electrical equipment and improper disposal or spills (ATSDR, 2000). The fate of individual PCB congeners is determined by both environmental processes and the physical-chemical properties of individual congeners. In general, PCB congeners that are more highly chlorinated and have fewer ortho substitutions are less volatile, less water soluble, bind more readily to organic particulate matter and are more amenable to anaerobic dechlorination processes (typically in buried sediments). Thus, these congeners are more prominent in soils and sediments, less prominent in water and in the atmosphere, and have higher bioaccumulation factors (BAFs). Congeners that are less chlorinated and have more ortho substitutions are more volatile, more water soluble and are much more readily metabolized in mammals. Consequently, these congeners are more prominent in the atmosphere, surface waters and in fish from temperate waters (Hansen, 1999). Hydrophobicity is the most important chemical property that controls bioavailability from water, sediment or soils. Hydrophobicity can be estimated by the octanol-water partition coefficient, K ow. Generally, log K ow s for PCBs increase from approximately 3 to 9 as degree of chlorination increases (Hansen, 1999). Hence, lower chlorinated PCBs having lower K ow s are more bioavailable than higher chlorinated congeners having higher K ow s. PCBs that are highly hydrophobic are difficult to measure in water because of the very small concentrations in solution. Conversely, concentrations in surficial sediments or soils are often measurable and can be used effectively to reference each PCB congener s distribution to abiotic and biotic components of the ecosystem. In aquatic ecosystems, concentrations measured in surficial sediments can be used to estimate average concentrations in water. Specifics regarding non-dioxin-like PCB congener disposition in environmental compartments and transfers among them are detailed by Hansen (1999). A detailed discussion of the dynamics and interplay between these processes is beyond the scope of this document, but have been presented in detail elsewhere for PCBs generally (ATSDR, 2000; Robertson and Hansen, 2001) and for non-dioxin-like congeners specifically (Hansen, 1999). 3.3 Disposition in the Environment: Media Due to historical releases and redistribution among environmental compartments, PCBs are widely distributed in environmental media and biota. Of the 209 possible congeners, 8
13 ~113 are found in environmental media and/or biota (McFarland and Clarke, 1989). Reports of PCBs, either measured as total PCBs or Aroclors, in environmental media and biota are abundant in the literature. Fewer congener-specific characterizations are found, especially in the older literature. In the environment, PCBs are always found as mixtures of both dioxin-like and non-dioxin-like PCB congeners. Hansen (1999) provides a more recent summary of the disposition of PCBs in the environment, with special emphasis on the non-dioxin-like congeners. Hansen points out that global disposition may not be relevant to site-specific assessment, but there will always be an atmospherically derived background PCB concentration which will often be regionally similar. While it is possible to generalize about specific congener fate, transport and disposition based on physical-chemical properties of PCBs, ultimately the congener profile of interest for a site-specific ecological risk assessment will be dependent upon the specific congeners present in the source material (e.g., which Aroclors were used/disposed of) and the physical and/or chemical processes relevant for the location. For example, the congener profile present in media and biota at a site where only a single Aroclor mixture was ever used/disposed may be quite different from the profile found at a manufacturing plant which produced the full spectrum of PCB products. The literature is also replete with reports of PCBs in environmental media and organisms from numerous sites around the world. Physical, chemical and ecological similarities (e.g., sources, transport pathways, biological systems lentic vs. lotic, etc.) between sites may serve as a basis for extrapolating congener profiles. 3.4 Disposition in the Environment: Biota PCB toxicity cannot be determined simply by examining the environmental concentrations of the congeners. Differential rates of uptake, metabolism and elimination will influence the congener profile to which target tissues are ultimately exposed. Detailed discussions of the disposition of PCBs in various taxa and the role of various toxicokinetic factors that influence the bioaccumulation of PCB congeners is beyond the scope of this report, but have been summarized elsewhere (Hansen, 1999; Robertson and Hansen, 2001; ATSDR, 2000). Some generalizations can be made however. Aquatic invertebrates serve as a major source of PCBs in food chains and seem to retain polar metabolites of metabolizable PCBs, which then biomagnify in the food chain. Uptake of PCBs in fish and invertebrates occurs via contact with media (i.e., respiration of water; contact with sediment), but food chain transfer is a major contributor for predatory organisms. Uptake of PCBs in piscivorous mammals and birds is primarily from ingestion of fish. As a class of compounds, PCBs are relatively resistant to metabolism by animals and the resistence to metabolism increases with degree of chlorination. Most congeners are metabolized to some extent and differential or selective metabolism among species appears to have the greatest influence on net PCB accumulation (Hansen, 1999). PCB congener profiles in mammals are generally similar, but species-specific differences in absorption, disposition and metabolism certainly exist. The PCB congener profiles in fish differ considerably from birds and mammals and consistently include greater proportions of congeners that are more labile in mammals. For example, measurements 9
14 of biota-sediment accumulation factors (BSAFs) for fish clearly demonstrate that very few PCB congeners are significantly metabolized, but that PCB 77 is a notable exception (Endicott and Cook, 1994; U.S. EPA, 1995c). Overviews of dose-, congener-, species- and time-dependent PCB profiles in aquatic and marine food chains is presented by Hansen (1999). McFarland and Clarke (1989) provide a congener-specific summary of the occurrence and abundance of all 209 PCBs found in several classes of animals from various trophic levels collected from several different sites world-wide. Although this paper presents only a snapshot of PCB profiles for organisms from specific sites, it provides a template of the sort of data one might desire to collect for an ecological risk assessment. The literature pertaining to bioaccumulation and biotransformation of PCBs in birds has been reviewed by Barron et al. (1995). Bioaccumulation and clearance of 42 individual PCB congeners following exposure of American kestrels to a mixture of Aroclors has been characterized by Drouillard et al. (2001). Congener-specific bioaccumulation of a number of individual PCB congeners in three trophic levels of an aquatic food web has been described and biotransfer factors for four water bird species determined (Zimmermann et al., 1997). Numerous reports document PCB profiles in higher trophic level birds collected from the field (e.g., Custer et al., 2002; Herzke et al., 2002; Elliot et al., 2001; van den Brink and Bosveld, 2001). Information on the PCB profiles present in aquatic and avian species will also serve as a basis for examining exposure of wildlife mammals via ingestion of such species. 4. Biological Effects of Non-Dioxin-Like PCBs Some non-dioxin-like PCBs have been shown to elicit different types of responses than the dioxin-like PCBs, including neurological, neuroendocrine, endocrine, immunological and carcinogenic effects. These effects occur via multiple toxicity pathways, not involving the AHR. Currently, only a small number of individual non-dioxin-like PCBs have been linked to any one of these effects and it should be realized that a single congener may act through one or more pathways. Likewise, some weak dioxin-like congeners, or their metabolites (i.e., mono-ortho chlorinated congeners), may also initiate toxicity via these pathways, independent of the AHR. However, in order to assess risks posed via these toxicity pathways, the pathways must be demonstrated to be active in a particular organism or class of organisms. Furthermore, dose-response relationships for toxicity elicited via these other pathways must be characterized to determine whether effects of non-dioxin-like PCBs are occurring at concentrations less than those elicited by dioxin-like PCBs that are always found in the environment along with the non-dioxin-like PCBs. While PCBs have been shown to affect various physiological system(s) in some classes of organisms, this is not necessarily the case for all taxa. Table 3 summarizes the toxicity pathways that have, to date, been shown to be affected by non-dioxin-like PCBs and those organisms in which PCBs have elicited effects attributable to those toxicity pathways. 10
15 The following sections summarize what is currently known regarding the toxicity pathways activated by non-dioxin-like PCBs in different biological systems. The congener-specific data provided represents the data that currently exists in the literature (i.e., only a very small number of individual congeners have been examined for activity through the various non-dioxin-like toxicity pathways). Lack of mention of a particular congener in association with a toxicity pathway does not imply that the congener does not act through this pathway, rather that the congener has not been tested for activity via the pathway. The data presented here should not be interpreted to be all-inclusive, as characterization of non-ahr-mediated effects of PCBs is an active area of research and new data appear in the literature daily. Table 3. Toxicity Pathways Documented for Non-Dioxin-Like PCBs Organism Class Toxicity Pathway Invertebrate Fish Birds Mammals Narcosis X X X X Liver Effects N/A?? X Neurochemical / behavioral??? X Endocrine / Neuroendocrine? hydroxy PCBs? X Immunological X?? X 4.1 Toxicity Pathways Narcosis is a non-specific mechanism of toxicity that may be elicited in any organism by any organic compound, including non-dioxin-like PCBs, at sufficiently high concentrations. Other potential toxicity pathways, such as endocrine/neuroendocrine disruption, neurotoxicity, and immunotoxicity, of non-dioxin-like PCBs are currently being studied in all classes of organisms and as they are elucidated, some toxic effects of non-dioxin-like PCBs observed in any of these classes of organisms may be attributable to them. Non-dioxin-like PCB toxicity occurring via other toxicity pathways has been established for mammals. Although evidence for non-dioxin-like PCB activity via other toxicity pathways in birds, fish and invertebrates is mounting, the majority of information on PCB toxicity has not focused on measures of effects associated with these toxicity pathways. Hence, most PCB toxicity data for birds characterize dioxin-like toxicity and those for fish characterize either narcosis (acute exposures; high concentrations) or dioxin-like toxicity (early life stage toxicity; low concentrations). The bulk of existing data for invertebrates describe their general insensitivity to PCBs, with toxicity observed at high concentrations, consistent with narcosis as the mode of action. It is assumed that non-dioxin-like PCB toxicity that occurs via any of the more specific toxicity pathways will occur at concentrations lower than those which induce narcosis (Carey et al., 1998). 11
16 4.1.1 Narcosis Narcosis, also referred to as baseline toxicity or anesthesia, is elicited by organic chemicals in all organisms given sufficient exposure and assuming a more potent toxicity pathway is not initiated at a lower dose. Narcosis is thought to be initiated through chemical-mediated perturbations of membrane-bound proteins, either through direct interactions or modification of the protein-membrane lipid interface or microenvironment. Narcotic effects are generally considered to be reversible until death occurs. For aquatic organisms, narcosis has been characterized in laboratory toxicity tests, and relationships between octanol/water partition coefficients, lethality and critical body residues are well established. The common toxicity pathway and established concentration-residue-response relationships allow mixtures of chemicals (including PCBs) to be assessed cumulatively using additivity approaches (DiToro and McGrath, 2000; DiToro et al., 2000; Van Leeuwen et al., 1992). Narcotic mode of action and toxicity are summarized concisely by Carey et al. (1998) and presented in detail in numerous reviews (DiToro and McGrath, 2000; DiToro et al., 2000; Bradbury et al., 1989). Mammals & Birds - Examples of PCB-induced narcosis in laboratory studies for mammals and birds are generally not available because sufficiently high steady-state blood concentrations of PCBs can not be attained through oral exposures. Under chronic exposure scenarios with lower doses, effects of PCBs via AHR-mediated toxicity pathways have been well documented. Likewise, effects that may be found to occur via non-dioxin-like toxicity pathways as described in the following sections would also be expected to occur at concentrations below those which cause toxicity via narcosis (Carey et al., 1998). Therefore, for most ecological risk assessment scenarios, mammalian and avian assessment endpoints should be based on toxicity endpoints other than narcosis. Fish - Lethality of PCB mixtures (e.g., Aroclors) and individual non-dioxin-like PCBs in fish following acute aqueous exposures are generally attributed to narcosis. For example, there are numerous reports of Aroclor-induced lethality in fish (see ECOTOX/AQUIRE database: The symptomology observed in these tests shows responses characteristic of narcosis and the toxicity can be accurately described using related QSARs (Van Leeuwen et al., 1992; Veith et al., 1983). Other toxic effects of nondioxin-like PCBs that occur at lower concentrations/doses and through longer exposures, which are elicited through other toxicity pathways (e.g. endocrine disruption), are beginning to be elucidated as described in the following sections. It is anticipated that effects occurring via these more specific toxicity pathways would occur at concentrations below those which cause toxicity via narcosis (Carey et al., 1998). Invertebrates - Distinction between dioxin-like and non-dioxin-like PCBs in reference to invertebrate toxicity is obviated due to the apparent lack of an AHR-mediated toxicity pathway in this class of organisms. Although AHR homologs have been identified in a variety of invertebrate species (Hahn, 1998) they apparently lack the ability to bind the 12
17 prototypical AHR ligands, 2,3,7,8-TCDD and $-naphthoflavone (Butler et al., 2001). Hence, all toxicity elicited by PCB in invertebrates is considered to occur via non-dioxinlike toxicity pathways. Several studies are of particular interest in evaluating the toxicity of individual congeners to invertebrates. These studies include Borgmann et al. (1990; PCB 52 in Hyalella azteca), Dillon et al. (1990; PCBs 52, 101, 118, 138, 153, 180 in Daphnia magna), Dillon and Burton (1991; PCBs 18, 116, 128, 153, 171, 194 in Daphnia magna), Fisher et al. (1999; PCBs 1, 15, 47, 153 in Lubriculus variegatus), Smith and Johnston (1992; PCB 15 in shrimp, Crangon crangon) and Schweitzer et al. (1997; PCBs 47 and 153 in purple sea urchin, Stongylocentrotus prupuratus). The PCB concentrations used in these studies were very high (often exceeding water solubility) and the invertebrates were most often found to be unaffected by the PCBs. A report by Hwang et al. (2001; PCB 153 in Chironomus riparius) is a recent addition to the database of effects of PCBs on invertebrate fecundity and development. Comprehensive summaries of toxic effects caused by PCB mixtures and individual PCB congeners in a variety of invertebrates are provided by Niimi (1996) and Jarvinen and Ankley (1999). In those cases where toxicity was observed in these studies, it occurred at relatively high concentrations and was consistent with narcosis (West et al., 1997; Fisher et al., 1999). Many of these studies have been summarized and evaluated by the U.S. EPA for their potential utility for deriving wildlife criteria values (U.S. EPA, 2002) Liver Effects Hepatotoxicity of commercial mixtures of PCBs in mammals is well documented and includes a number of endpoints including increased liver weight, biochemical changes (e.g., enzyme induction, porphyrin accumulation), histopathology, and tumors as compiled recently by ATSDR (2000). However, congener-specific effects data, generally, and non-dioxin-like congener effects data, specifically, are quite limited. Furthermore, such endpoints are typically not used as measurement endpoints in ecological risk assessments because it is often difficult to clearly link these effects to adverse outcomes on either individuals or populations of ecological receptors. Although not necessarily useful for ecological risk assessment, a brief summary of reports of liver effects, particularly those that may be useful in distinguishing dioxin-like effects from non-dioxin-like effects, is provided. A few studies utilizing various mammalian models have examined effects of specific congeners on liver endpoints. The general trend is for the endpoints examined to be responsive to dioxin-like PCBs, but not non-dioxin-like PCBs (reviewed in ATSDR, 2000). Structure-activity relationships for PCB-induced biochemical and histopathological responses are not well established, but have been reviewed previously (Safe, 1994; Marks, 1985). Liver effects in birds and fish have largely been described within the context of dioxin-like effects, or lack thereof. Hence, several non-dioxin-like congeners have been assessed for their ability to cause non-specific liver lesions (e.g., weight changes, protein concentration changes) and/or induce CYP1A, but effects 13
18 specific to non-dioxin-like congeners have not been established. These data for mammals, birds and fish are summarized below. Mammals - Both dioxin-like and non-dioxin-like PCBs are hepatic tumor promoters in rodents. In two-year bioassays of Aroclors 1016, 1242, 1254 and 1260, all of these mixtures were considered carcinogenic, particularly in female rat livers. When the doses of these mixtures were expressed on a TEC basis (i.e., dioxin-like PCBs only), the doseresponse relationship for Aroclor-induced tumors in female rat liver is similar to that observed for TCDD, except for the Aroclor 1016 mixture. The Aroclor 1016 mixture contains the lower chlorinated PCBs and has little dioxin-like activity and the carcinogenic effect of this mixture may be attributed to the non-dioxin-like PCBs present. Unlike TCDD, liver tumors were observed in the male rats receiving Aroclor 1260, suggesting that these effects are mediated through pathways other than the Ah receptor. Other liver effects, including increased liver weight, biochemical changes (e.g., enzyme induction, porphyrin accumulation) were also observed in the aforementioned studies. Similar to the carcinogenic effects, the female rats were more sensitive than the males and Aroclor 1016 was much less potent than the other mixtures. These studies suggest that the hepatic toxicity of mixtures of PCBs are largely due to the dioxin-like congeners in these mixtures (ATSDR, 2000). In mammals, induction of liver enzymes distinct from cytochrome P4501A, namely cytochrome P450s 2A and 3B (CYP2A/3B), have been linked to non-dioxin-like PCBs (reviewed by Bandiera, 2001). Although the molecular mechanism(s) underlying CYP2B/3A induction has not been elucidated, this endpoint, in the absence of CYP1A induction, could be used as a biomarker of non-dioxin-like PCB exposure and/or effects (WHO, 2001; Bandiera, 2001). Liver porphyrin accumulation in response to PCB exposure, both PCB mixtures and individual PCB congeners, has been studied in several mammalian species (see ATSDR, 2000 for review). Dioxin-like PCB congeners 105, 128 and 126, but not 77, cause porphyrin accumulation in rats (ATSDR, 2000; van Birgelen et al., 1996). In contrast, non-dioxin-like PCB congeners 28, 118, 153 and 156 reportedly are not porphyrinogenic in rats. While a strong association between AHR responsiveness and porphyrinogenic responses indicates that the porphyrinogenic response in mammals is largely AHRmediated (ATSDR, 2000), non-dioxin-like PCBs have been reported to greatly enhance AHR-mediated porphyrin accumulation. It appears that both dioxin-like and non-dioxinlike PCBs may affect the heme biosynthetic pathway via different molecular mechanisms (van Birgelen et al., 1996; Marks, 1985). Birds - While induction of cytochrome P450s isozymes other than 1A1 have been associated with exposure to non-dioxin-like PCBs in mammals, this relationship has not been established in birds. Kennedy et al. (1996) have reported induction of EROD activity in chicken embryo hepatocytes treated with the non-dioxin-like congeners #2, 12, 35, 37, 78, 79, 80, 66, 70, 110, 122, 128, 138, 139, 167, 170, 180, and 194. Lorenzen et 14
19 al. (1997) report that PCBs 52, 54, 101, 136 and 153 failed to induce EROD activity or CYP1A protein in chicken embryo hepatocytes, but were able to induce porphyrin accumulation at high concentrations. Quail exposed to PCB 153 displayed increased liver weights, but the occurrence of porphyria and CYP1A induction caused the authors to suspect that the PCB was contaminated with dioxin-like congeners, which was confirmed by chemical analysis (Elliot et al., 1997). In ovo exposure of chicken eggs to PCB 153 failed to cause liver lesions and other early life stage effects associated with exposure to dioxin-like congeners (Zhao et al., 1997). Like the CYP1A induction response, the porphyrinogenic response to PCB exposure in birds is not clearly associated with only the dioxin-like PCB congeners. Several studies using chick embryo liver cells show that although dioxin-like PCB congeners are more potent porphyrinogenic agents, certain non-dioxin-like congeners (e.g., 66, 128, 153, 155, (non-dioxin-like) also possess porphyrinogenic activity, albeit much weaker (Goldstein et al., 1976; Kawanishi et al., 1978; Marks, 1985; Sassa et al., 1986). Similarly, Miranda et al. (1987) have reported porphyrinogenic responses in Japanese quail exposed to both PCB 77 (dioxin-like) and 47 (non-dioxin-like). Sassa et al. (1986) have used the chick embryo liver data to demonstrate that porphyrinogenic potency is correlated with chlorine substitution patterns that convey planarity of the PCB molecule. Hence, while the structural determinants for porphyrinogenic potency of dioxin-like PCBs are the same as those which determine AHR responsiveness, it remains to be determined whether nondioxin-like PCBs may act on the heme biosynthetic pathway via other mechanisms as has been postulated to occur in mammals (van Birgelen et al., 1996). Fish - While induction of cytochrome P450s isozymes other than 1A1 have been associated with exposure to non-dioxin-like PCBs in mammals, this relationship has not been established in fish. The ability of a few non-dioxin-like PCB congeners to induce CYP1A protein and/or EROD activity has been assessed. PCBs 128 and 138 were tested in scup (Stenotomus chrysops) in vivo (Gooch et al., 1989); PCBs 128, 138, 153 and 170 were tested in a zebrafish (Danio rerio) liver cell line (Henry et al., 2001) and PCB 153 was tested in a topminnow (Poeciliopsis lucida) hepatoma cell line (Bruschweiler et al., 1996). None of the non-dioxin-like congeners tested were effective at inducing fish CYP1A. These data do not provide evidence linking non-dioxin-like PCB exposure in fish tissues to an enzyme induction biomarker as has been established in mammals, but they do reinforce the association of CYP1A induction as an effect that is specific to dioxin-like congeners in fish Endocrine / Neuroendocrine Function A broad range of xenobiotics, including PCBs, may have the potential to alter endocrine function. Endocrine disrupting activity is of concern for ecological risk assessment because most physiological, developmental and reproductive processes in both invertebrates and vertebrates are controlled by one or more endocrine systems. Endocrine disruptors may directly or indirectly mimic or inhibit the production or action of a variety 15
20 of steroids including estrogens, progestins, androgens, adrenal steroids and thyroid hormones. Individual PCB congeners may act through one or more endocrine pathways to cause effects and individual congeners in a mixture may have opposing activities (e.g., estrogenic and anti-estrogenic). These actions may occur via a variety of molecular or biochemical events in a number of cells, tissues or organs within a given endocrine system (e.g., hypothalamus, pituitary, gonad, thyroid, adrenal, steroid metabolism, etc.). Characterizing the effects of PCBs on the various endocrine systems is further complicated by the fact that the concentrations, actions and potencies of steroids and other endocrine active compounds can vary considerably during different life stages and reproductive cycles. Thus, the potential for PCBs to disrupt endocrine activity will need to be determined on a congener-specific basis to establish structure-activity relationships for specific endocrine effects and subsequently the means to assess cumulative effects of mixtures of environmental congeners. It is well established that PCBs, including both dioxin-like and non-dioxin-like congeners and hydroxylated metabolites of some congeners (i.e., hydroxylated PCBs) may affect endocrine systems in vertebrates (Cooke et al., 2001). Issues related to the characterization of endocrine-related effects of PCBs have been reviewed in detail elsewhere (Brouwer et al., 1998; ATSDR, 2000; Cooke et al., 2001). PCB-induced endocrine effects are summarized below for mammals, birds fish and invertebrates. The summaries provided focus on effects that have been attributed specifically to non-dioxinlike PCB congeners, but Aroclor effects data are presented if they are the only data available that demonstrates the potential for PCB-induced endocrine effects for a class of organisms. Mammals - Reports of the effects of PCBs on various endocrine systems in mammals following exposure to Aroclors are abundant and have been reviewed elsewhere (ATSDR, 2000; Brouwer et al., 1998). These reports provided the impetus for further investigating the mechanisms underlying such effects and for determining specific PCB congeners that elicit effects through a common pathway. The Aroclor studies will not be discussed further here. The remainder of this section will focus on describing endocrine/neuroendocrine effects for which causality has been unambiguously linked to non-dioxin-like PCB congeners. Reproductive - Effects of non-dioxin-like PCBs in a variety of mammalian endocrine systems have been described (Cooke et al., 2001; Fischer et al., 1998). Much of the individual congener data has been collected from in vitro model systems in an attempt to elucidate the means by which disruption of endocrine pathways can be initiated. For example, several studies have demonstrated that hydroxylated PCBs bind to the estrogen receptor (Layton et al., 2002; Yoon et al., 2001; Matthews and Zacharewski, 2000; Kuiper et al., 1998). Other studies have demonstrated that hydroxylated PCBs inhibit estrogen sulfation that may result in increases in target tissue concentrations of estradiol (Kester et al., 2000). Congener specific data from in vivo studies are limited. 16
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text:
Natural Gas Daily Technical Outlook
Nymex Natural Gas (NG)
Intraday bias in natural gas remains on the downside with 4.35 minor resistance. CUrrent fall from 5.196 is still expected to continue for a retest on 3.81 key support level next. On the upside, above 4.35 minor resistance will turn intraday bias neutral and bring recovery. But another fall would remain in favor as long as 5.007 resistance holds.
In the bigger picture, the main question remains on whether Natural gas's fall from 6.108 is finished at 3.71 already as it just drew strong support from 61.8% retracement of 2.409 to 6.108 at 3.822. We'll stay neutral first. On the downside, break of 3.81 will revive the case that whole medium term rebound from 2.409 is finished at 6.108 already and will bring even deeper fall to retest this low. On the upside. Though, note that break of 5.007 will argue that rise from 2.409 is not finished yet and will extend for making another high above 6.108 before completion.

subset: commoncrawl


text:
End Mountaintop Removal
The Untold American Tragedy in Appalachia
As millions of Americans go about their daily lives, thousands in the Appalachian coal region are quietly suffering - and even dying - from poisoned water, polluted air, and catastrophic flooding associated with the unprecedented environmental and humanitarian crisis of mountaintop removal. Find out more about mountaintop removal >>
These stories can no longer go untold and unaddressed.
Proverbs 31:9 tells us, "Speak up and judge fairly; defend the rights of the poor and needy."
Ezekiel prophesies, "Woe to the shepherds of Israel who only take care of themselves! Should not the shepherds take care of the flock?" (34:2).
It's time for us to look beyond ourselves,
and see our brothers and sisters suffering in Appalachia. We must work to end the largely untold tragedy of mountaintop removal.
For many of us, the natural next question is "What can we do?"
There are two things that you can do right now.
1. Give 2 minutes.
Stand with Appalachian residents by asking our public leaders to take initiative on this critical issue and protect the people, mountains and streams of Appalachia. Use our easy online advocacy tools to ask your senator to end mountaintop removal.
2. Give $15 or more.
Help Restoring Eden continue to raise awareness about mountaintop removal by supporting our work financially. Enter "MTR" as the designation code.


text:
We seek to acquire portfolios from Brokers across the UK who wish to sell all or part of their business and our aim is to retain and grow each acquired portfolio to give you a great return on your business.
Our special insurer arrangements mean that we remain able to retain motor and home clients in a price comparison led market. If you are looking to sell part or all of your business in the next 6 months or 6 years, please call us in total confidence.
With significant funding from our parent company, Zurich, Endsleigh can offer you a competitive price for your insurance business. We have experienced professionals on hand to support and guide you through our efficient and quick sales process.
And of course you can have confidence that we keep all information 100% private.
I want to retire soon is now a good time to sell?
I want to sell a book of business which I don't specialise in and focus on my core business.
I want to release some of the cash in my business.
I need to release capital in order to grow my business.


text:
Reporter: Jane Hutcheon
KERRY O'BRIEN: On the international front, a dark shadow hangs over the Middle East peace plan after yesterday's suicide bombing in Jerusalem that killed 20 people and wounded about 100.Two radical Islamic groups, Hamas and Islamic Jihad, have both claimed responsibility.The Israeli Government has warned the Palestinian authority that there won't be any progress towards peace without action against the militant groups.But a growing number of Israelis and Palestinians aren't waiting for their politicians to forge peace between the two peoples.They're making their own efforts to break the cycle of violence which has claimed more than 3,000 lives -- two-thirds of them Palestinian -- in the past three years.Bereaved parents are trying to assist others in a bid to help them come to terms with their grief -- among them the Roth family, formerly of Melbourne, who lost 15-year-old daughter Malki in a suicide bombing in Jerusalem two years ago.This report from the ABC's Middle East correspondent Jane Hutcheon.JANE HUTCHEON: Arnold Roth remembers the day two years ago that his 15-year-old daughter Malki died in a massive blast in central Jerusalem.Hamas activist Izzedine al-Masri detonated a bomb carried on his body with horrifying effect.15 Israelis, including Melbourne-born Malki and her best friend Mihal, died instantly.They'd made a last-minute stop for pizza before attending youth group.ARNOLD ROTH: She was a person who really had a dynamic inside her, a spirit that motivated her to care about other people and she was in this sense an unforgettable person.JANE HUTCHEON: Though the Roths still mourn her, they turned despair into action, starting a foundation in Malki's name to aid families with disabled children both Israeli and Arab.The Roths own youngest daughter is severely disabled.ARNOLD ROTH: For me it's a kind of act of revenge.I have a very clear view of the kind of mentality that the young man from a wealthy, well to do family, who blew himself up and killed 15 innocent people in the process, had in his mind and as much as he was possessed of hatred, I want us to be directed in the exact opposite way.To me, that will obliterate his memory from the face of the earth, and do good at the same time.JANE HUTCHEON: Worlds away in the West Bank town of Beit Omah, a fragile cease-fire within a teetering peace process.Every day, Palestinian life is controlled by the Israeli army in the name of security.On the edge of Palestinian towns like Beit Omah, Israeli soldiers maintain a permanent presence in the form of this watch tower you can see behind me.Palestinians say every day they have to face the people they call the occupiers and aggressors.But one group of people has decided that there's been enough hostility and enough killing.Khaled Abu Awad has every reason to harbour bitterness toward Israel.Two of his brothers, one of them just 14, killed by Israeli soldiers.But today he takes children from his town on an adventure -- all have lost loved ones in the three-year uprising.KHALED ABU AWAD, PARENTS CIRCLE: We don't want the soldiers in our village.We don' want all these checkpoints and all these problems there.If we want to see the Israeli people, we want to see them like visitors in our country, not as soldiers.JANE HUTCHEON: The children are heading to a 3-day camp to meet Israeli kids who've also lost loved ones, killed in the familiar pattern of tit-for-tat violence.The idea came from from the Parent's Circle, a group of people like Khaled Abu Awad and Israeli Robi Damelin.Everyone in the Parent's Circle has a story of personal loss.This man's son was kidnapped and murdered by Hamas militants nine years ago.And Robi's 28-year-old son David, a reserve soldier, was shot by a Palestinian sniper last year.ROBI DAMELIN, PARENTS CIRCLE: After David was killed, I was looking to find something -- I've had a PR office for many years and I worked with the good things in life, you know, the wine and food and books and culture, and it suddenly didn't have any meaning for me.JANE HUTCHEON: Despite a US-backed peace process, a cease-fire has been shattered with alarming force this week.Mistrust between Israelis and Palestinians has never been higher.Robi Damelin believes bereaved parents have a unique bond that has already turned enmity into friendship.ROBI DAMELIN: No peace movement made by leaders above will work until we begin to know each other.It's taking this bereavement and putting it into something to make a difference and wanting to get up in the morning.JANE HUTCHEON: The children of Beit Omah arrive at camp.The Israeli kids are already here.There's an initial chill, obvious in the body language.But before any mistrust can settle in, their minds are put to work.It doesn't take long before the ice breaks.ROBI DAMELIN: The idea is to get them to interact for four to five days and to create a friendship by the end of this because they can go out and be ambassadors to their friends and maybe that will start to grow from that age-group.JANE HUTCHEON: For Khaled Abu Awad, a lifelong commitment sprung from grief at the loss of his brothers.KHALED ABU AWAD: I have to change my life.I have to do anything that can be help to put an end to all these problems, to all these killings.Why they have to kill us?Why we have to kill them?Why?JANE HUTCHEON: Behind a conflict that has claimed 3,000 lives in three years, faces of sadness and anger.But here too lie seeds of hope that those touched by violence may turn heartbreaking grief into greater good.
Transcripts on this website are created by an independent transcription service. The ABC does not warrant the accuracy of the transcripts.


text:
FULL-LENGTH MATCH - Raw - Shawn Michaels vs. Shelton Benjamin MP3
Relive one of the greatest matches in Raw history! Subscribe Now - http://www.youtube.com/user/wwe?sub_confirmation=1.
Shawn Michaels' WrestleMania XII Entrance MP3
Shawn Michaels ziplines down from the top of Arrowhead Pond into the WWE Universe minutes before his WWE Iron Man Match with Bret Hart.
Seth Rollins interrupts Shawn Michaels: Raw, October 19, 2015 MP3
As WWE Hall of Famer HBK recounts his Hell in a Cell history, The Architect has some bold words for The Showstopper. More ACTION on WWE NETWORK ...
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WWE Championship Match - Bret 'The Hitman' Hart defends against his seemingly life long rival WWE Intercontinental Champion, 'Heartbreak Kid' Shawn ...
FULL-LENGTH MATCH - Raw - Batista vs. Shawn Michaels - Lumberjack Match MP3
Oct. 13, 2008 - Chris Jericho picks the opponent for Batista and the type of match The Animal must compete in.
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Shawn Michaels descends from the heavens in his quest to defeat The Undertaker at WrestleMania.
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Check out one of the biggest tag team matches in Raw history 6 days before WrestleMania 23.
HBK's Legacy vs. HHH's Legacy MP3
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Nov. 25, 2002 - It's a dream match we thought we'd never see. Shawn Michaels and Rob Van Dam go one-on-one for the first time ever with the World ...
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text:
Omega Boost - still image by FarinsWatch
©2008-2017 Farins
Still image of Omega Boost
Daily DeviationGiven 2011-02-23
Omega Boost - still image by ~Farins. Suggester Statement: Brilliant piece, 3d all about details and i found this job with wonderful angle... ( Suggested by junaidplaner and Featured by KeremGo )
Such an underrated gem for sure.
This is probably the best boost image online. Good job man, great detail.
This is pretty much the best.
this is a fucking kick ass picture, OH MAN do I loved this game (thats why I own it)!
yeah, me too, unfergettable.
I thought there would be more Omega Boost-art enthusiasts for the game on this website, I wonder why?
This is the best boost art I've seen. Badass.
Couldn't believe that this game is related to Gran Turismo 5!!!
this reminds me of the armored core series
Omega Boost, it's all set, carry out the mission carefully.
If you don't mind me sharing some stories, I actually got up to this part: [link] in-game the other day. Up until that point I just thought 'That BGM is so awesome!' but then I actually fought the boss. O_O Uhh how am I supposed to beat it in 180 seconds!? Oh the weak spot on its behind. OH CRAP THERE'S ANOTHER BOSS RIGHT AFT-ASDFHJK.
Great job. Love it.
Awesome work
that was a fun game
AAAHHH!!! I had a LOVE affair with this game when i was younger! so much younger than todaaaaay! he he he
woah the details are amazing, pretty damn cool! and it kinda reminds me of a mecha form of thomas from daft punk
nothing but pure amazing!
nothing but pure amazing!
kinda look like a mecha isaac clarke
OMFG O_O This has got to have been one of my favourite games of all time!!
wow!really awesome!great details
insane details...wicked coloring and concept...
OMG, i loved the game, i love your art. I wish there were a remake of the game and you could lead the concept design area.
I Love It
That's a weapon!!!!
That's a very godamm weapon...
That's a weapon!!!!
That's a very godamm weapon...
I can't believe that a man could do something similar...fantastic
It's like he's asking, "How do you want to die? I can give you options."
How do the kids these days say it? "Hellz yeah!" comes to mind lol.
way sick...im a fan of detail and this is phenominal
A. W. E. Some.
This is an awesome piece of work. I commend you. I used to own this game on the old PS1/2. I hope it gets released to the playstation store in the USA one day.
This is an awesome piece of work. I commend you. I used to own this game on the old PS1/2. I hope it gets released to the playstation store in the USA one day.
amazing details!!!
This is totally beyond win, Apologies for the inane comment but still. Awesome!
Wow! this is so amazing!!! Congrats!!!
i dare someone to say he came from K-mart!
Can I have one? Please...


text:
I'm very close to my family and value them immensely!
Staying fit is a non-negotiable part of my life. I love the physical and mental stimulation of dancing - salsa, waltz, and Argentine tango! I'm a big hugger...I hope you are too! Life is a journey. I believe in enjoying the ride!
With that said, I think I am ready for something more serious...
Somebody to enjoy sunsets with... Somebody to enjoy my time with family and friends with... Somebody I will cheer and root for with all my heart!
I am Concupiscient, Inquisitive, and Adventurous
2. Dyed hair
3. Very extroverted
B. Movies - Somethings Gotta Give, Usual Suspects, Juno, Slumdog Millionaire
C. Music - a little of everything...variety is a must
D. Food - a little of everything...variety is a must
2. Communication - I love talking to and learning from people
3. Information access - Doesn't matter if it's electronic or analog in nature
4. Ability to express myself - Too many people conform
5. A gym - I need a place to workout
6. People from other places - I love learning about new cultures and perspectives.
2. Conversing with friends about the human condition over wine.
3. Salsa and/or Argentine tango.
1) explore the world with
2) try new things with
3) explore iterative experimentation (on whatever we find interesting)
4) be a partner in life
5) dance with


text: Spend a day fishing in the C&O Canal! Instructors and all the gear you will need to catch fish are provided! When not fishing, children will participate in fun, educational activities like water quality testing, fly casting or fly tying, fish art, scavenger hunts, touch tanks, and so much more! Partner agencies and organizations will have displays set up to learn about how they are helping fish and fishing across the country. Don't miss this fantastic day of family fun!


text:
60 days GRE/BAM
- Geologists, geophysicists and reservoir engineers, with 1 to 3 years of experience involved in basin analysis and prospect generation, and in the evaluation of exploration-related risks.
- This course provides a comprehensive, practical knowledge of basin exploration, analysis & modeling workflow, and to develop competencies and know-how via hands-on activities, case studies and simulations based on state-of-the-art techniques and methods for play assessment and prospect definition.
Learning Objectives
- Upon completion of the course, participants will be able to:
- have a clear comprehension of analysis methods and techniques applied to basin exploration and related challenges,
- analyze and interpret a dataset from a specific basin, and integrate the data in order to elaborate a reliable petroleum system model,
- build a structural, stratigraphic and sedimentological model, and track back basin evolution in order to understand play concept and define related prospects,
- characterize the evolution of a basin, and build the corresponding stratigraphic and thermal model,
- contribute to the reduction of uncertainty and risks, and optimize investments.
- This training program suits candidates with an engineering degree, a master degree in geosciences or an equivalent diploma, technicians involved in an upgrade process or who wish to validate their know-how in covered disciplines.
- A previous experience is not mandatory but can facilitate the learning process.
Ways and means
- An important part of the formation is dedicated to hands-on activities and simulations on real cases.
- Emphasis is put on practical work to develop participants' autonomy and their capacity to make appropriate decisions.
- Both personal and group work will contribute to team-building, stimulate debating and communicating about results.
- Case studies are carried out on most popular software tools used in the petroleum industry.
Exploration geology disciplines
- Lectures, hands-on activities and case studies are distributed in several modules of one- to two-week long.
Training content presents a clear operational orientation in order for participants to get familiar with specific techniques via an extensive exposure to simulations on real cases allowing them to anticipate the problems they will have to cope with later in their own projects.
- The course covers the following topics: Petroleum exploration techniques and methods; Petroleum system analysis; Seismic and well data interpretation; Basin infilling and architecture for trap geometry prediction; Prospect generation and assessment of related risks and uncertainties; Basin analysis and modeling.
- Part 1: Exploration techniques (15 days)
- Petroleum geology
- Hunting for Oil (serious game on E&P overview) (E-101).
- Petroleum systems (hydrocarbons from source rock to reservoirs) (E-121).
- Structural geology, basin development and associated traps (E-122).
- Part 2: Basin analysis (30 days)
- Well log analysis (15 days)
- Sedimentology and sedimentological well log interpretation.
- Well logging and qualitative log interpretation (E-123).
- Quantitative well log analysis (E-221).
- Seismic and stratigraphy (15 days)
- 3D seismic interpretation workshop (structural & stratigraphic) (E-124).
- Sedimentology & sequence stratigraphy workshop (E-125).
- Part 3: Basin evaluation and modeling
- Prospect evaluation (5 days)
- Play assessment and prospect generation (E-126).
- Final project – Basin modeling workshop (10 days)
- Stratigraphic modeling (basin architecture and sediment distribution) (E‑127).
- Basin modeling (thermicity, maturation and migration) (E-128).
Project report defence & jury
- The training program ends with a project on a real case. Participants are involved in a simulated situation and their mission is to summarize, integrate and apply acquired knowledge. Each team will present final results of a project to a jury.