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Query: UMLS:C0271276 (Hudson)
 1,066 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Full congener-specific polychorinated biphenyl (PCB) and partial-congener-specific polychorinated dibenzo-p-dioxin/furan (PCDD/F) analyses were performed on livers from young-of-the-year (YOY) and adult Atlantic tomcod from the Hudson River estuary including multiple sites along the main-stem Hudson River and Newark Bay/Hackensack River, NJ, and from a reference river, the Miramichi River, NB. Highest hepatic burdens of PCBs were found in fish collected in the main-stem Hudson River between river miles (RM) 37 and 50 and in Newark Bay/Hackensack River. By far, the highest concentrations of PCDD/Fs were seen in fish from Newark Bay/Hackensack River. The di- to tetrachlorinated biphenyls dominated the PCB composition in YOY tomcod, whereas the penta- to nonachlorinated biphenyls predominated in adults with particular prevalence of the 2,4,5-substituted diortho congeners. Overall, using a direct mixing model an aroclor composition of approximate 1:1:1, A1242:A1254:A1260, was calculated from the hepatic PCB profiles in YOY tomcod. A linear increase in A1242 characteristics with river mile was seen in YOY collected between RM 0 and RM 80, which was likely due to the well-characterized A1242 source from the former capacitor manufacturing plants located upriver. However, tomcod caught upstream of RM 80 exhibited a PCB pattern with decreasing A1242 characteristics, and it was hypothesized that this was due to the increased depuration or decreased uptake of low chlorinated (log K(OW) < 6) congeners upon entry of the fish into freshwater from brackish water. The most abundant tetra-octa PCDD/F chlorohomologue in tomcod collected from the main stem of the Hudson River was TCDF, whereas 2,3,7,8-TCDD was the major congener detected in tomcod from Newark Bay/Hackensack River, which showed elevated total PCDD/F levels compared to tomcod from the main-stem Hudson River.
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PMID:Spatial variation in hepatic levels and patterns of PCBs and PCDD/Fs among young-of-the-year and adult Atlantic tomcod (Microgadus tomcod) in the Hudson River estuary. 1499 7

Narthecium ossifragum (L.) Hudson was subjected to artificial deposition events in three experiments. In the first, a laboratory experiment, 1.0 m nitrate significantly decreased the growth of Narthecium, and the shoot and root nitrogen content of the plants was increased in all enhanced nitrogen treatments. In the second experiment, solutes were applied in situ to a relatively unpolluted upland ombrotrophic mire at concentrations measured in cloud water at a polluted site in England. There was no effect on Narthecium tissue nitrogen concentration due to either ammonium or nitrate applied alone but the shoot nitrogen was significantly increased when the ammonium and nitrate were applied in combination. In the third experiment, a piece of upland ombrotrophic mire from a relatively unpolluted site in North Wales was transplanted to a polluted site in northern England. After two years both the shoots and roots of Narthecium present in the mire showed a higher nitrogen concentration in the transplant compared with the control. These data show that nitrogen supply in the southern Pennines is supra-optimal for Narthecium, which implies that in such situations it (and other species with a similar ecological strategy) would be out-competed by more vigorous species. The data from the field experiment at the relatively unpolluted site imply that even there, nitrogen supply is close to supra-optimal for Narthecium.
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PMID:An experimental investigation of the effects of nitrogen deposition to Narthecium ossifragum. 1509 85

In June 2003, two injections of approximately 3.9 mol of sulfur hexafluoride (SF6) were made 8 days apart in the East River, a 25 km tidal strait, to observe solute mixing and dissipation. The first injection occurred at slack before flood, and the second at slack before ebb (flood = northward flow). Tidally synchronized surveys of the SF6 tracer patch, supplemented by vertical profiles, were conducted by boat for 6 and 4 days following the flood and ebb injections, respectively. Residence times for the tracer-tagged water mass in the East River were estimated to be 3.3 +/- 0.7 days and 1.7 +/- 0.5 days for the flood and ebb injections, respectively, after correcting SF6 inventories for losses of SF6 from the water column by air-water gas exchange. The data indicate that the majority of East River solutes are transported to New York Harbor and that tidal mixing dominates subtidal circulation with respectto solute transport. Surveys of the adjacent lower Hudson River revealed a northward-moving, intermediate layer of East River water. Our results suggest that tidal phasing of contaminant discharges in the East River could reduce environmental impacts, by increasing flushing rates and directing a greater fraction of material away from Long Island Sound.
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PMID:Effect of tides on solute flushing from a strait: imaging flow and transport in the East River with SF6. 1546 Nov 64

The effects of global warming can increase the risk of exotic species introductions in eastern Canadian Arctic waters by reducing surface ice cover and allow increased access to commercial vessels. Ballast water discharged by incoming overseas vessels is an important means for introducing species on a global scale. Analyses of air temperatures at Churchill, Manitoba between 1943 and 2002 indicated an increase in mean temperature within the past decade. Churchill is the only major northern port in this region where grain has been exported on a limited basis due to the short navigation season. Economic analyses of grain exported from Canadian and U.S. ports indicated some cost advantages for using northern ports. The Hudson Bay region is vulnerable to increased exotic species introductions because of its southerly location. Current ballast water exchange measures to reduce the risk of introductions may not be effective because most vessels enter the region with ballast, and the ballast exchange zone is located relatively close to coastal areas where the habitat could be favorable for an introduced species to become established. The probability of a large crab species introduced to this region from northern European waters is discussed. The risk of ballast water-related exotic species introduction to this region may be reduced by expanding the types of cargo handled and developing a strong import market. This approach would accommodate an increase in the number of vessels with cargo, and substantially reduce the volume of ballast carried to this region.
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PMID:Environmental and economic factors can increase the risk of exotic species introductions to the Arctic region through increased ballast water discharge. 1550 88

Global climate change is expected to severely impact Arctic ecosystems, yet predictions of impacts are complicated by region-specific patterns and nonuniform trends. Twentyfour open-water overwintering areas (or "microhabitats") were identified to be of particular importance for eight seabird and marine mammal species in the eastern Canadian High Arctic and Baffin Bay. Localized trends in the available fraction of open-water were examined in March during 1979--2001, derived from approximate sea ice concentrations from satellite-based microwave telemetry. Declines in the fraction of open-water were identified at microhabitats in Baffin Bay, Davis Strait, coastal West Greenland, and Lancaster Sound. Increases in open-water were observed in Hudson Bay, Hudson Strait, and Foxe Basin. The biological importance of each microhabitat was examined based on species distribution and abundance. Potential consequences of reduced open-water for top marine predators include impacts on foraging efficiency and oxygen and prey availability.
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PMID:Declining extent of open-water refugia for top predators in Baffin Bay and adjacent waters. 1566 78

Chemical fate and transport models that simulate sediment-water exchange of contaminants typically employ empirically determined sediment-water exchange coefficients for the dissolved fraction to describe the net effect of poorly understood mechanisms. This paper presents field-derived observations of the coefficient for 12 PCB congeners and two PCB mixtures in the Thompson Island Pool, Hudson River, and also presents an evaluation of a theoretical sediment-water exchange model. An extensive PCB data set was used to compute apparent coefficients for PCBs in the pool. Average exchange coefficients for the 12 congeners ranged from 2.6 to 18.8 cm/ day, and results showed a strong seasonal dependence. Peak coefficient values occurred in mid-May to early July, preceding peak water temperatures by 1 month and lagging the spring high-flow period. The coefficients increase with increasing partition coefficients, suggesting a dependence on congener properties. The large magnitude of the coefficients and the variation among the congeners is inconsistent with the pore-water molecular-diffusion transport process. A theory-based, mechanistic two-layer model reproduces the nonlinear relationship between the sediment-water exchange coefficients and partition coefficients. This model includes transfer through the mixed sediment layer by bioturbation and diffusion transfer through a water-side boundary layer governed by flow velocity. Results suggest that this algorithm can provide increased accuracyto future system-level fate and transport models for hydrophobic chemicals. The seasonal variation in the transfer coefficient appears to be a poorly understood interaction of physical and biological processes and merits further study.
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PMID:Field observation and modeling of dissolved fraction sediment-water exchange coefficients for PCBs in the Hudson River. 1570 55

Organochlorine pesticides and PCBs were analysed in blubber from beluga (Delphinapterus leucas), or white whales, collected at 15 sites in the Canadian Arctic between 1993 and 2001. The objective of the study was to define and interpret the spatial trends of major organic contaminants in northern beluga in terms of sources and transport pathways, and the biological factors influencing accumulation. When compared on a lipid weight basis, the concentrations of beta-HCH, cis-CHL and SigmaCHL, cis-nonachlor, heptachlor epoxide and p,p'-DDT were significantly higher in males than females at all five sites in the eastern Arctic where the two sexes were harvested. The differences were attributed to losses from the females during fetal development and lactation as reported in previous studies. Major compounds increased with age in males at most sites, however the lack of a significant increase with age at some sites was in part due to high organochlorine concentrations in young year classes (2-5 years), particularly at eastern sites such as Iqaluit and Pangnirtung. Lower concentrations of SigmaHCH and SigmaDDT compounds in young males in 2001 relative to 1995 at Hendrickson Island could be due to declining levels in the environment, changes in the diet, or differences in organochlorine loads transferred from the female after birth. Age-corrected least square mean concentrations in males showed significantly higher levels of many compounds, such as p,p'-DDE and SigmaCHB, at south Baffin Island sites than those in the west. Two notable exceptions were HCBz and beta-HCH which were higher in the west. Methoxyclor was detected in males at Sanikiluaq (58 ng g-1) and in both sexes at Kimmirut, but at no other sites. Principal component analysis grouped the 16 sites into five major groupings based on the similarity of normalised organochlorine pesticide and PCB levels. Sites from the western Arctic were grouped by higher proportions of HCBz, beta-HCH and gamma-HCH and higher chlorinated PCBs. Endosulfan and alpha-HCH comprised a larger proportion of total organochlorine residues in the northern Hudson Bay sites, while methoxychlor, chlordane compounds and octachlorobiphenyls were enriched at Sanikiluaq in eastern Hudson Bay. The analysis showed that the relative amounts of several key compounds are similar in the beluga stocks over large spatial areas (i.e. eastern versus western sites), however, some stocks have distinct fingerprints which can be used to differentiate them from adjacent stocks. Ratios of major HCH isomers largely corresponded with air and surface water measurements conducted during the 1990s, but low alpha-/beta- and alpha-/gamma-HCH ratios in all three western Arctic collections indicate rapid losses of the alpha-isomer from the food web, proportionately higher beta- and gamma-isomers in the Beaufort Sea, or a combination of the two processes. Chlordane residue patterns generally correspond to those from previous studies, however, interpretation of spatial trends are difficult due to the aging of the probable sources in the south, possible atmospheric input from new sources and complex transport pathways.
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PMID:Spatial trends and factors affecting variation of organochlorine contaminants levels in Canadian Arctic beluga (Delphinapterus leucas). 1615 19

Although polychlorinated biphenyls (PCBs) and polybrominated diphenyl ether (PBDE) flame retardants are important organic contaminants in the tissues of marine mammals, including those species from the Arctic, there is exceedingly little direct evidence on congener-specific biotransformation. We determined and compared the in vitro metabolism of environmentally relevant PCB (4,4'-di-CB15, 2,3',5-tri-CB26, 2,4,5-tri-CB31, 2,2',5,5'-tetra-CB52, 3,3',4,4'-tetra-CB77, 2,2',4,5,5'-penta-CB101, 2,3,3',4,4'-penta-CB105 and 2,3',4,4',5-penta-CB118), and PBDE (4,4'-di-BDE15, 2,4,4'-tri-BDE28, 2,2',4,4'-tetra-BDE47, 2,2',4,5'-tetra-BDE49, 2,2',4,4',5-penta-BDE99, 2,2',4,4',6-penta-BDE100, 2,2',4,4',5,5'-hexa-BDE153, 2,2',4,4',5,6'-hexa-BDE154 and 2,2',3,4,4',5',6-hepta-BDE183) congeners using hepatic microsomes of a beluga whale (Delphinapterus leucas) from the Arviat (western Hudson Bay) area of the Canadian Arctic. Ortho-meta bromine-unsubstituted BDE15, BDE28 and BDE47 were significantly metabolized (100%, 11% and 5% depleted, respectively) by beluga, whereas control rat microsomes (from pooled male Wistar Han rats) metabolized BDE28, BDE49, BDE99 and BDE154 (13%, 44%, 11% and 17% depleted, respectively). CB15 and CB77 (putative CYP1A substrates) were more rapidly metabolized (100% and 93% depleted, respectively) by male beluga than CB26 and CB31 (CYP1A/CYP2B-like) (25% and 29% depleted, respectively), which were more rapidly metabolized than CB52 (CYP2B-like) (13% depleted). Higher chlorinated CB101 and CB105 showed no depletion. Rat control microsomes metabolized CB15 to a lesser extent (32% depleted) than beluga, but much more rapidly transformed CB52 (51% depleted, respectively). Within the 90 min in vitro assay time frame, the preference was towards metabolism of ortho-meta unsubstituted congeners (for both PCBs and PBDEs) in beluga whale, whereas for rat controls, meta-para unsubstituted congeners also substantially metabolized. For both beluga whale and rat, metabolic rates were inversely associated with the degree of halogenation. For the rapidly biotransformed CB15 and BDE15, water-soluble OH-metabolites were detected after incubation. These results indicate that CYP-mediated oxidative hepatic biotransformation is a metabolic pathway in the toxicokinetics of both PCB and PBDE congeners in beluga whales and in the rat model. This may suggest that the formation of potentially toxic oxidative PCB and PBDE products (metabolites), in addition to the parent pollutants, may be contributing to contaminant-related stress effects on the health of beluga whale.
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PMID:Biotransformation of polybrominated diphenyl ethers and polychlorinated biphenyls in beluga whale (Delphinapterus leucas) and rat mammalian model using an in vitro hepatic microsomal assay. 1632 35

We investigated the growth and vertical flux of attached bacteria with floating sediment traps in the Hudson River Plume of the New York Bight during the spring diatom blooms. Traps were floated at the base of the mixed layer (ca. 10 m) for 1-day periods. After recovery, we measured bacterial abundance and rates of [methyl-H]thymidine incorporation in the trap samples. The vertical flux of attached bacteria was estimated with a model formulated to distinguish between bacterial accumulation in traps due to in situ growth and that due to vertical flux. Attached bacterial flux ranged from 0.6 x 10 to 2.0 x 10 cells m day, and attached bacterial settling rates of 0.1 to 1.0 m day were observed during periods of vertical particulate organic carbon flux ranging from 254 to 1,267 mg of C m day. In situ growth of bacteria in sediment traps was unimportant as a source of bacterial increase when compared with vertical flux during our study. The vertical flux of attached bacteria removed 3 to 67% of the total daily bacterial production from the water column. Particulate organic carbon is not significantly mineralized by attached bacteria during its descent to the sea floor in the plume area during this period, when water temperature and grazing rates are at their annual minima.
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PMID:Production and vertical flux of attached bacteria in the hudson river plume of the new york bight as studied with floating sediment traps. 1634 87

Populations of organisms that are chronically exposed to high levels of chemical contaminants may not suffer the same sublethal or lethal effects as naive populations, a phenomenon called resistance. Atlantic tomcod (Microgadus tomcod) from the Hudson River, New York, are exposed to high concentrations of polycyclic aromatic hydrocarbons (PAHs) and bioaccumulate polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). They have developed resistance to PCBs and PCDDs but not to PAHs. Resistance is largely heritable and manifests at early-life-stage toxic end points and in inducibility of cytochrome P4501A (CYP1A) mRNA expression. Because CYP1A induction is activated by the aryl hydrocarbon receptor (AHR) pathway, as are most toxic responses to these compounds, we sought to determine the geographic extent of resistance to CYP1A mRNA induction by PCBs in the Hudson River tomcod population. Samples of young-of-the-year tomcod were collected from seven locales in the Hudson River, extending from the Battery at river mile 1 (RM 1) to RM 90, and from the Miramichi River, New Brunswick, Canada. Laboratory-reared offspring of tomcod adults from Newark Bay, in the western portion of the Hudson River estuary, were also used in this study. Fish were partially depurated in clean water and intraperitoneally injected with 10 ppm coplanar PCB-77, 10 ppm benzo[a]pyrene (BaP), or corn oil vehicle, and levels of CYP1A mRNA were determined. CYP1A was significantly inducible by treatment with BaP in tomcod from the Miramichi River, from laboratory-spawned offspring of Newark Bay origin, and from all Hudson River sites spanning 90 miles of river. In contrast, only tomcod from the Miramichi River displayed significantly induced CYP1A mRNA expression when treated with PCB-77. Our results suggest that the population of tomcod from throughout the Hudson River estuary has developed resistance to CYP1A inducibility and probably other toxicities mediated by the AHR pathway. Tomcod from the Hudson River may represent the most geographically expansive population of vertebrates with resistance to chemical pollutants that has been characterized.
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PMID:Evidence of spatially extensive resistance to PCBs in an anadromous fish of the Hudson River. 1639 62


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