Contaminant exposure and reproductive success of ospreys (Pandion haliaetus) nesting in Chesapeake Bay regions of concern.

The Chesapeake Bay osprey population has more than doubled in size since restrictions were placed on the production and use of DDT and other toxic organochlorine contaminants in the 1970s. Ospreys are now nesting in the most highly polluted portions of the Bay. In 2000 and 2001, contaminant exposure and reproduction were monitored in ospreys nesting in regions of concern, including Baltimore Harbor and the Patapsco River, the Anacostia and middle Potomac rivers, and the Elizabeth River, and a presumed reference site consisting of the South, West, and Rhode rivers. A "sample egg" from each study nest was collected for contaminant analysis, and the fate of eggs remaining in each nest (n = 14-16/site) was monitored at 7- to 10-day intervals from egg incubation through fledging of young. Ospreys fledged young in regions of concern (observed success: 0.88-1.53 fledglings/active nest), although productivity was marginal for sustaining local populations in Baltimore Harbor and the Patapsco River and in the Anacostia and middle Potomac rivers. Concentrations of p,p'-DDE and many other organochlorine pesticides or metabolites, total PCBs, some arylhydrocarbon receptor-active PCB congeners and polybrominated diphenyl ether congeners, and perfluorooctanesulfonate were often greater in sample eggs from regions of concern compared to the reference site. Nonetheless, logistic regression analyses did not provide evidence linking marginal productivity to p,p'-DDE, total PCBs, or arylhydrocarbon receptor-active PCB congener exposure in regions of concern. In view of the moderate concentrations of total PCBs in eggs from the reference site, concerns related to new and emerging toxicants, and the absence of ecotoxicological data for terrestrial vertebrates in many Bay tributaries, a more thorough spatial evaluation of contaminant exposure in ospreys throughout the Chesapeake may be warranted.

Alkylphenol ethoxylate degradation products in land-applied sewage sludge (biosolids).

Alkylphenol ethoxylates, widely used in commercial and household detergents in the United States, can degrade during the wastewater treatment process to more toxic, estrogenic, and lipophilic compounds. These include octylphenol (OP), nonylphenols (NPs), nonylphenol monoethoxylates (NP1EOs), and nonylphenol diethoxylates (NP2EOs). These compounds have received considerable attention due to their acute toxicity and ability to disrupt the endocrine system. In Europe, regulations have been established to control their impact on the environment. In this study, biosolids derived from all 11 U.S. wastewater treatment plants examined contained detectable levels of OP, NPs, NP1EOs, and NP2EOs. Nine exceeded the current Danish land application limit (30 mg/kg; sum of NPs, NP1EOs, and NP2EOs) by 6-33x. NPs were the major component, and their concentrations therein ranged from 5.4 to 887 mg/kg (dry weight). OP, reportedly 10-20x more estrogenic than NP, was detected in these same nine biosolids at levels up to 12.6 mg/kg. Three biosolids were also subjected to the U.S. Environmental Protection Agency Toxicity Characteristic Leaching Procedure Method 1311. NPs and NP1EOs were both detected in the leachate; the former at concentrations from 9.4 to 309 microg/L. On the basis of effect levels published in the literature, alkylphenol ethoxylate degradates in U.S. biosolids may cause adverse environmental impacts.

Polybrominated diphenyl ether flame retardants in Virginia freshwater fishes (USA).

Polybrominated diphenyl ethers (PBDEs) were examined in fish fillets collected from two large Virginia watersheds. Emphasis was on the tetra- to hexabrominated congeners since these exhibit the greatest bioaccumulation and toxicological potentials. These congeners are dominant constituents of Penta-, a commercial PBDE product used to flame retard polyurethane foam. In 1999, North America accounted for98% of global Penta-demand. Concentrations of total tetra- to hexabrominated congeners in fillets ranged from <5 to 47,900 microg/kg (lipid basis). BDE-47, one of the two major constituents of Penta-, was detected in 89% of samples and contributed 40-70% of the total PBDEs observed. Concentrations of BDE-99, the second major constituent of the Penta- commercial mixture, were much lower in fish. While some differences in PBDE profiles between fish species were apparent, dominant congeners were consistent with those in surficial sediments from the Virginia sites and recently published data for U.S. air samples. PCB and PBDE concentrations in fish were generally associated. These factors point to exposure from nonpoint sources. Exceptions existed, likely due to inputs from local sources. The Virginia study area has historically served as a center for furniture and textile manufacturing, although polyurethane foam production here has been limited.

PCB uptake and accumulation by oysters (Crassostrea virginica) exposed via a contaminated algal diet.

Reproductively active oysters were fed daily with 0.2 g algal paste containing 0, 0.1, and 1.0 microgram polychlorinated biphenyls (PCBs) (1:1:1 mixture of Aroclor 1242, 1254 and 1260) for either 15 or 30 days, and accumulation of PCBs in different organ tissues and eggs assessed. The effects of PCB exposure on lipid content, lipid class and fatty acid composition were also evaluated. PCBs were accumulated by the oysters and transferred to the eggs. PCB accumulation in oysters was dose, time and tissue dependent. Mean PCB contents were 3150, 1970, and 250 ng/g dry wt., respectively, in the visceral mass, gills + mantle and muscle of oysters fed algal paste containing 1.0 microgram PCBs for 30 days. The PCBs in the eggs from the same oysters reached 671 ng PCBs/g dry wt. Feeding oysters with PCB-sorbed algal paste for 30 days significantly increased phospholipid and free fatty acid contents in gills + mantle tissue compared to the same tissues in the undosed control.

Effects of PCBs sorbed to algal paste and sediments on the stress protein response (HSP70 family) in the eastern oyster, Crassostrea virginica.

This study examined the stress protein response (HSP70 family) of reproductively inactive oysters fed 0.7 g algal paste containing 0, 0.35 and 3.5 micrograms polychlorinated biphenyls (PCBs) daily. A second set of treatment groups investigated the combined effect of PCBs and sediments (0.3 g sediments daily per oyster) on HSP70 response. After 8 weeks of PCB exposure, oyster tissues (mantle and gill) were sampled and analyzed for HSP70. Preliminary results did not show a significant effect in HSP70 response in oysters fed PCB sorbed to algal paste, albeit PCBs accumulated up to 1342 ng/g dry weight in the mantle, and up to 180 ng/g dry weight in gill tissues. However, the addition of sediments caused a significant increase in HSP70 levels of gills and mantle, although the mantle was less sensitive to the sediments.

Biomechanical and metabolic effects of varying backpack loading on simulated marching.

Twelve healthy, male Army recruits performed three, 40-min treadmill marches at 6 km/h, under three load carriage conditions: 0%-body weight (BW) backpack load, 15%-BW load and 30%-BW load. Kinematic and kinetic data were obtained, immediately before and after each treadmill march, for computing ankle, knee and hip joint rotations and moments. Metabolic data (oxygen uptake (VO2), expired ventilation (VE), respiratory exchange ratio (RER)), heart rate (HR) and ratings of perceived exertion (RPE) were collected continuously during marching. Significant differences (p < or = 0.05) were observed between each load for VO2, HR and VE throughout the marches. At 40 min, relative energy costs for 0%-BW, 15%-BW and 30%-BW loads were 30, 36 and 41% VO2max, respectively. RPE responses during marching significantly differed for only the 30%-BW load and were greater than responses at 0%-BW and 15%-BW loads. During load carriage trials prior to treadmill marches (pre-march), peaks in internal, hip extension, knee extension and ankle plantar flexion moments increased with increasing backpack load. Relative to 0%-BW load, percentage increases in knee moments, due to 15%-BW and 30%-BW loads, pre-march, were substantially larger than the percentage increases for hip extension and plantar flexion moments, pre-march. Pre-march and post-march peaks in hip extension and ankle plantar flexion moments were similar with all loads, while notable pre-march to post-march declines were observed for knee extension moment peaks, at 15%-BW and 30%-BW load. Pre-march joint loading data suggests that the knee may be effecting substantial compensations during backpack loaded marching, perhaps to attenuate shock or reduce load elsewhere. Post-march kinetic data (particularly at 15%-BW and 30%-BW load), however, indicates that such knee mechanics were not sustained and suggests that excessive knee extensor fatigue may occur prior to march end, even though overall metabolic responses, at 15%-BW and 30%-BW load, remained within generally recommended limits to prevent fatigue during prolonged work.

Toxicity of creosote water-soluble fractions generated from contaminated sediments to the bay mysid.

Creosote, a globally used wood preservative, is a complex mixture consisting primarily of aromatic organic compounds (ACs). Creosote-derived ACs can persist for decades in aquatic sediments. Natural and anthropogenic activities may result in dissolution and resuspension of sediment-associated ACs. These processes were mimicked by generating a water-soluble fraction (WSF) from creosote-contaminated sediment (ERS) collected from a polluted site. The epibenthic mysid Mysidopsis bahia was exposed to five sublethal concentrations of WSF for 7 days. The WSF significantly decreased dry weight gain and proportion of gravid females (EC50=15 microgram/liter total identified ACs). Chemical analysis indicated that high-molecular-weight ACs (more than three aromatic rings) dominated the ERS, but were undetected in the WSF. Low-molecular-weight ACs (fewer than three aromatic rings) dominated the WSF. Compositional differences can thus result from fractionation processes and affect environmental fate and toxicity of the mixture.

Determination of coal tar and creosote constituents in the aquatic environment.

Creosote and its parent material, coal tar, are complex mixtures. Upon release their components fractionate into the air, water, soil/sediment and biota; as a function of their physical and chemical properties. Therefore, assessment of their fate and concentrations in the environment must consider a wide variety of both compounds and matrices. Analyses are typically complicated, consisting of sample extraction, purification and chromatography-based final characterization steps. Several new techniques have been introduced to reduce or simplify the number of steps, solvent and time required. Recently developed extraction methods include supercritical fluid, accelerated solvent, microwave and solid-phase microextraction. On-line purification and coupling of extraction and chromatography have also emerged. HPLC and GC remain the major tools for performing the final separations. Application of mass spectrometry has increased as more reliable, versatile and less expensive units have become available, such as the ion trap and mass selective detectors. Fluorescence and diode array UV, in concert with HPLC, and C-, S- and N-selective gas chromatographic detectors are also being applied.

Accumulation of polychlorinated terphenyls in aquatic biota of an estuarine creek.

Aroclor 5432, a mixture of polychlorinated terphenyls (PCT), was detected in several biological compartments including saltmarsh cordgrass (Spartina alterniflora), American oysters (Crassostrea virginica), red-jointed fiddler crabs (Uca minax), wharf crabs (Sesarma reticulatum), and mummichogs (Fundulus heteroclitus) collected from Tabbs Creek. This tidal creek is located in the southern Chesapeake Bay region and contains sediments with high concentrations of PCT. Samples were collected at four sites, ranging from a suspected outfall near the head of the creek, to its mouth, approximately 2.5 river kilometers downstream. Species from several phyla were selected in order to examine PCT accumulation in physiologically and ecologically different organisms. PCT concentrations in sediment, saltmarsh cordgrass, native oysters, and fiddler crabs decreased with distance downstream. Residues in transplanted oysters and mummichogs showed a more variable trend with distance downstream. The organism with the highest mean concentration (18,300 micrograms/kg dry wt) was the native oyster, a benthic filter feeder.

Methods for the analysis of persistent chlorinated hydrocarbons in tissues.

Chlorinated hydrocarbons bioaccumulate in tissues and may have severe health consequences. These compounds occur individually, in small groups or as complex mixtures; examples of each category include aldrin, hexachlorocyclohexane and the polychlorinated biphenyls. Tissue extraction and purification schemes have been established, although new approaches such as supercritical fluid extraction are promising. Analyses often require the resolving power of capillary gas chromatography, in combination with the sensitivity and selectivity of electron-capture detection, electrolytic conductivity detection and mass spectrometry. Difficulties arise in quantitating chlorinated hydrocarbons in tissues, due to the number of components present and the fact that individual constituents may be reduced or enhanced in concentration in tissues, compared with the original formulation. Congener specific analysis and computer-assisted identification techniques have been applied to the problem.