Effects of bioaugmentation on indigenous PCB dechlorinating activity in sediment microcosms

Bioaugmentation is an attractive mechanism for reducing recalcitrant pollutants in sediments, especially if this technology could be applied in situ. To examine the potential effectiveness of a bioaugmentation strategy for PCB contamination, PCB dehalorespiring populations were inoculated into Baltimore Harbor sediment microcosms. A culture containing the two most predominant indigenous PCB dehalorespiring microorganisms and a culture containing a strain with a rare ortho dechlorination activity and a non-indigenous strain that attacks double-flanked chlorines, were inoculated into sediment microcosms amended with 2,2′,3,5,5′,6-hexachlorobiphenyl (PCB 151) and Aroclor 1260. Although we observed a similar reduction in the concentration of PCB 151 in all microcosms at day 300, a reduced lag time for dechlorination activity was observed only in the bioaugmented microcosms and the pattern of dechlorination was altered depending on the initial combination of microorganisms added. Dechlorination of Aroclor 1260 was most extensive when dehalorespiring microorganisms were added to sediment. Overall numbers of dehalorespiring microorganisms in both bioaugmented and non-bioaugmented microcosms increased 100- and 1000-fold with PCB 151 and Aroclor 1260, respectively, and they were sustained for the full 300 days of the experiments. The ability of bioaugmentation to redirect dechlorination reactions in the sediment microcosms indicates that the inoculated PCB dehalorespiring microorganisms effectively competed with the indigenous microbial populations and cooperatively enhanced or altered the specific pathways of PCB dechlorination. These observations indicate that bioaugmentation with PCB dehalorespiring microorganisms is a potentially tractable approach for in situ treatment of PCB impacted sites.     

Acute non-cancer mortality excess after polychlorinated biphenyls and polychlorinated dibenzofurans mixed exposure from contaminated rice oil: Yusho

In Japan in 1968, rice-oil contaminated by polychlorinated biphenyls and polychlorinated dibenzofurans caused severe food poisoning, termed “Yusho” (oil disease). Several previous studies attempted to evaluate the effects targeting officially-certified Yusho patients. However, these studies have several limitations such as the left-truncated nature of the registry or residual confounding arising from the referent population selection. We thus conducted an area-based standardized mortality ratios (SMRs) study using vital statistics. A severely affected area (Tamanoura area) was adopted as the exposure group, with a reference population from Nagasaki prefecture in Kyushu, which included the Tamanoura. A large number of residents in Tamanoura were exposed to the rice-oil (28% of all the certified cases as of 2009). We estimated SMRs of non-cancer and cancer diseases for the years 1968-2002. Shortly after the exposure, SMRs of all causes, diabetes mellitus, cardiovascular disease, pneumonia/bronchitis, and bronchus/lung cancer were elevated. In particular, SMRs of heart disease were 1.97 [95% confidence intervals (CI): 1.09-3.56] in 1968, 2.05 (95% CI: 1.16-3.60) in 1969, and 1.89 (95% CI: 1.05-3.41) in 1975. However, we did not observe clear increase in SMRs more than 10 years after the exposure. This study provides further evidence in Yusho, especially on acute effects on non-cancer mortality.     

Relationship between persistent organic pollutants (POPs) and ranging patterns in common bottlenose dolphins (Tursiops truncatus) from coastal Georgia, USA

Bottlenose dolphins (Tursiops truncatus) are apex predators in coastal southeastern U.S. waters; as such they are indicators of persistent organic pollutants (POPs) in coastal ecosystems. POP concentrations measured in a dolphin's blubber are influenced by a number of factors, including the animal's sex and ranging pattern in relation to POP point sources. This study examined POP concentrations measured in bottlenose dolphin blubber samples (n = 102) from the Georgia, USA coast in relation to individual ranging patterns and specifically, distance of sightings from a polychlorinated biphenyl (PCB) point source near Brunswick, Georgia. Dolphin ranging patterns were determined based upon 5 years of photo-identification data from two field sites approximately 40 km apart: (1) the Brunswick field site, which included the Turtle/Brunswick River Estuary (TBRE), and (2) the Sapelo field site, which included the Sapelo Island National Estuarine Research Reserve (SINERR). Dolphins were categorized into one of three ranging patterns from photo-identification data. Individuals with sighting histories exclusively within one of the defined field sites were considered to have either Brunswick or Sapelo ranging patterns. Individuals sighted in both field sites were classified as having a Mixed ranging pattern. Brunswick males had the highest concentrations of PCBs reported for any marine mammal. The pattern of PCB congeners was consistent with Aroclor 1268, a highly chlorinated PCB mixture associated with a Superfund site in Brunswick. PCB levels in Sapelo males were lower than in Brunswick males, but comparable to the highest levels measured in other dolphin populations along the southeastern U.S. Female dolphins had higher Aroclor 1268 proportions than males, suggesting that the highly chlorinated congeners associated with Aroclor 1268 may not be offloaded through parturition and lactation, as easily as less halogenated POPs. Individuals sighted farther from the Superfund point source had lower Aroclor 1268 proportions.     

氯苯在飞灰表面低温生成二恶英的特性

以1,2,3-三氯苯作为前趋物,在管式炉中研究了其在垃圾焚烧飞灰表面低温生成二恶英的分布特性,运用高分辨气相色谱／低分辨质谱仪分别测定了气相和固相中的二恶英总量以及毒性当量I-TEQ值．实验结果表明, 250℃是1,2,3-三氯苯在飞灰表面生成二恶英的最佳温度,生成的二恶英主要分布在气相中,与五氯酚相比,氯苯属于反应活性低的二恶英前趋物．     

Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish

Persistent organic pollutants (POPs) encompass an array of anthropogenic organic and elemental substances and their degradation and metabolic byproducts that have been found in the tissues of exposed animals, especially POPs categorized as organohalogen contaminants (OHCs). OHCs have been of concern in the circumpolar arctic for decades. For example, as a consequence of bioaccumulation and in some cases biomagnification of legacy (e.g., chlorinated PCBs, DDTs and CHLs) and emerging (e.g., brominated flame retardants (BFRs) and in particular polybrominated diphenyl ethers (PBDEs) and perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA) found in Arctic biota and humans. Of high concern are the potential biological effects of these contaminants in exposed Arctic wildlife and fish. As concluded in the last review in 2004 for the Arctic Monitoring and Assessment Program (AMAP) on the effects of POPs in Arctic wildlife, prior to 1997, biological effects data were minimal and insufficient at any level of biological organization. The present review summarizes recent studies on biological effects in relation to OHC exposure, and attempts to assess known tissue/body compartment concentration data in the context of possible threshold levels of effects to evaluate the risks. This review concentrates mainly on post-2002, new OHC effects data in Arctic wildlife and fish, and is largely based on recently available effects data for populations of several top trophic level species, including seabirds (e.g., glaucous gull (Larus hyperboreus)), polar bears (Ursus maritimus), polar (Arctic) fox (Vulpes lagopus), and Arctic charr (Salvelinus alpinus), as well as semi-captive studies on sled dogs (Canis familiaris). Regardless, there remains a dearth of data on true contaminant exposure, cause-effect relationships with respect to these contaminant exposures in Arctic wildlife and fish. Indications of exposure effects are largely based on correlations between biomarker endpoints (e.g., biochemical processes related to the immune and endocrine system, pathological changes in tissues and reproduction and development) and tissue residue levels of OHCs (e.g., PCBs, DDTs, CHLs, PBDEs and in a few cases perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonates (PFSAs)). Some exceptions include semi-field studies on comparative contaminant effects of control and exposed cohorts of captive Greenland sled dogs, and performance studies mimicking environmentally relevant PCB concentrations in Arctic charr. Recent tissue concentrations in several arctic marine mammal species and populations exceed a general threshold level of concern of 1 part-per-million (ppm), but a clear evidence of a POP/OHC-related stress in these populations remains to be confirmed. There remains minimal evidence that OHCs are having widespread effects on the health of Arctic organisms, with the possible exception of East Greenland and Svalbard polar bears and Svalbard glaucous gulls. However, the true (if any real) effects of POPs in Arctic wildlife have to be put into the context of other environmental, ecological and physiological stressors (both anthropogenic and natural) that render an overall complex picture. For instance, seasonal changes in food intake and corresponding cycles of fattening and emaciation seen in Arctic animals can modify contaminant tissue distribution and toxicokinetics (contaminant deposition, metabolism and depuration). Also, other factors, including impact of climate change (seasonal ice and temperature changes, and connection to food web changes, nutrition, etc. in exposed biota), disease, species invasion and the connection to disease resistance will impact toxicant exposure. Overall, further research and better understanding of POP/OHC impact on animal performance in Arctic biota are recommended. Regardless, it could be argued that Arctic wildlife and fish at the highest potential risk of POP/OHC exposure and mediated effects are East Greenland, Svalbard and (West and South) Hudson Bay polar bears, Alaskan and Northern Norway killer whales, several species of gulls and other seabirds from the Svalbard area, Northern Norway, East Greenland, the Kara Sea and/or the Canadian central high Arctic, East Greenland ringed seal and a few populations of Arctic charr and Greenland shark.     

Great Lakes' contaminants reduce sperm production and fertilizing ability in mice

The long‐term effects of Great Lakes' contaminants on male reproductive performance resulting from lactational and dietary exposure were investigated. Female C57BL/6 J mice (F‐0) were mated with DBA/2 J male mice to produce B₆D₂‐F₁ offspring. Dams (F‐0) were fed one of three treatment diets during lactation. The three treatment diets were: (i) diet C, containing lab chow and fish oil; (ii) diet I, containing 60% Iowa carp and 40% lab chow; and (iii) diet G, containing 60% Great Lakes' carp and 40% lab chow. Diet C served as a lab‐chow control treatment, while diet I served as a fish‐diet control treatment. Diet G contained 2500 µg of polychlorinated biphenyls (PCBs) and 300 µg of 1,1‐dichloro‐2,2‐bis‐[p‐chlorophenyl]ethylene (4,4′‐DDE) per kilogram of feed. The offspring (F‐1) were continued on their respective maternal treatment diets from weaning until termination. Greater neonatal mortality and lesser body weights were observed in the F‐1 male mice on diet G. Lesser fecundity was observed in one‐year‐old F‐1 male mice on diet G following pairing with non‐treated female mice. The sperm concentration of F‐1 male mice on diet G was less than 30% of that of mice on diets C and I. The in vitro fertilizing ability of the sperm decreased to 10% of that of mice on the two control diets. Sperm motility, velocity, linearity and amplitude of lateral head (ALH) displacement were also decreased in 15‐month‐old F‐1 male mice on diet G.     

Dioxin-like and non-dioxin like effects of polychlorinated biphenyls: Implications for risk assessment

Polychlorinated biphenyls (PCBs) are persistent, bioaccumulative and toxic contaminants in the environment. Individual PCB congeners exhibit different physicochemical properties and biological activities that result in different environmental distributions and toxicity profiles. The variable composition of PCB residues in environmental matrices and their different mechanisms of toxicity complicate the development of scientifically based regulations for risk assessment. Various approaches for the assessment of risks of PCBs have been critically examined. Recent developments in the toxic equivalency factor (TEF) approach for the assessment of toxic effects due to dioxin‐like PCBs have been examined. The PCB exposure studies that describe non‐dioxin‐like toxic effects, particularly neurobehavioural effects and their effective doses in animals, were compiled. A comparative assessment of effective doses for dioxin‐like and non‐dioxin‐like effects by PCBs has been made to evaluate the relative significance of non‐ortho and ortho‐substituted PCBs in risk assessment. Using mink as an example, relative merits and implications of using TEF and total PCB approaches for assessing the potential for toxic effects in wildlife were examined. There are several advantages and limitations associated with each method used for PCB risk assessment. Toxic effects due to coplanar PCBs occur at relatively smaller concentrations than those due to non‐dioxin‐like PCBs and, therefore, the TEF approach derives the risk assessment of PCBs in the environment. The need for the refinement of the TEF approach for more accurate assessment of risks is discussed.     

Spatial Distributions of Legacy Contaminants in Sediments of Lakes Huron and Superior

The sediments of Lake Superior, Lake Huron, and Georgian Bay were sampled in 2001 and 2002 in order to evaluate the extent of surficial sediment contamination of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), polycyclic aromatic hydrocarbons (PAHs), and metals. Sediment concentrations of PCBs, OCs, PAHs, and mercury were generally low and up to 2 orders of magnitude less than in Lakes Erie and Ontario. In contrast, concentrations of metals such as arsenic, copper, and nickel were comparable to those in Lakes Erie and Ontario. These elevated Lakes Superior and Huron metal concentrations were attributed to naturally occurring metals within the bedrock, soil, and sediment of the study region. Concentrations of all contaminants were typically below the Canadian Sediment Quality Probable Effect Level (PEL) guidelines. With regard to spatial patterns, most contaminants were focused primarily in the depositional basins and atmospheric deposition was likely the major source of these chemicals to the lakes. The major exception was for metals (not including mercury) whose patterns were also influenced by natural sources as well as extensive mining activity. A comparison between surficial sediment contamination of samples collected as part of this survey and those collected in the late 1960s/early 1970s using similar methods showed that concentrations of DDT, PCB, lead, and mercury were generally similar between these two time periods. These results are not consistent with production and usage patterns that have declined substantially in the past 3 decades. We hypothesize that the lack of temporal trends is an artifact due to slow sediment accumulation rates as well as differences in analytical protocols between the two time periods.     

History of Lake Ontario Contamination from the Niagara River by Sediment Radiodating and Chlorinated Hydrocarbon Analysis

Contamination of Lake Ontario by persistent organic compounds began with the development of the chemical industry along the Niagara River. These compounds are discharged to the river where they are scavenged from the water column by sedimenting particulates which in turn settle out in depositional areas of Lake Ontario. We have determined ²¹⁰Pb, ¹³⁷Cs, and chlorinated hydrocarbon profiles of sediment cores taken about 3 km from the mouth of the Niagara River. Age profiles of the sediments were constructed from the radionuclide measurements and used to determine historic trends of chlorinated hydrocarbon input to Lake Ontario. The historical record found in the sediments for chlorobenzenes, chlorotoluenes, hexachlorobutadiene, octachlorostyrene, mirex, and PCBs is in good agreement with known production and usage patterns of the chemicals. Pollution of Lake Ontario with chlorinated hydrocarbons from the Niagara River is still occurring, but the worst contamination of the lake occurred in the 1960s.     

Organochlorine Pesticides,PBBs, And Mercury in Round Whitefish Fillets from Saginaw Bay,Lake Huron, 1977–1978

Successful development of a commercial, small-mesh trap net fishery for round whitefish (Prosopium cylindraceum) in Saginaw Bay, Lake Huron, prompted analysis of round whitefish fillets for selected contaminants [dieldrin, dichlorodiphenyl trichloroethane and metabolites (DDT), polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), chlordane, methyl mercury, and total mercury] to determine the fish's suitability for human consumption. Concentrations of all contaminants measured in 1977–1978 were below U. S. Food and Drug Administration action guidelines for fish; PBBs were below detection limits (0.001 mg/kg) for all fillets analyzed. Only PCBs and total DDT residues displayed a strong direct relationship with fish length. Fillets from males consistently exhibited higher mean concentrations of contaminants than did females. No changes in contaminant levels with season were observed.