Bioconcentration of polycyclic aromatic hydrocarbons by the freshwater oligochaete Lumbriculus variegatus

Tissue residues of the PAHs, anthracene, fluorene, fluoranthene and pyrene were determined in Lumbriculus variegatus at four time intervals during both a 96-h exposure period to monitor uptake, and a 96-h clean water period to assess depuration. Mean BCFs were 2390, 1210, 452 and 1920 for fluoranthene, anthracene, fluorene and pyrene, respectively. BCFs were positively correlated with the octanol/water partition coefficient values of the four PAHs. Depuration occurred most rapidly for fluorene, followed by anthracene and fluoranthene. No apparent depuration of pyrene was observed during the 96-h depuration period. Because of rapid depuration of some PAHs, it appears that the 24 h clean water gut clearance period recommended in conjunction with sediment bioaccumulation tests with L. variegatus has potential to result in an under-estimation of bioaccumulation of some chemicals.     

Molecular phylogenies help resolve taxonomic confusion with Asian <Emphasis Type="Italic">Crassostrea</Emphasis> oyster species

Identification of oyster species is still largely based on phenotypic characters that are highly plastic. Prompted by the proposed introduction of the Asian oyster species Crassostrea ariakensis into the Chesapeake Bay region of the U.S.A., this study uses molecular genetic information to understand the taxonomic framework surrounding C. ariakensis and to confidently distinguish among various sympatric oyster species. Putative samples of C. ariakensis and other species of cupped oysters from across Asia were collected and phylogenetic analyses were conducted on DNA sequences of both nuclear (ITS-1) and mitochondrial (COI) regions. Trees generated based on the two independent molecular datasets were highly congruent, and indicate that many oysters collected for this study as C. ariakensis were originally misidentified. Results also indicate that C. ariakensis, C. hongkongensis and C. nippona are distinct, but closely related species. There is strong support in both analyses for a close relationship between C. gigas and C. sikamea, as well as between C. belcheri and C. gryphoides, and between C. iredalei and C. madrasensis. The parsimony analyses based on these DNA markers, however, did not provide evidence to support C. angulata as a distinct species from C. gigas. Overall, the results emphasize the need for rigorous species identification, and additional extensive and intensive sampling to more accurately determine relationships among Crassostrea species, define their geographic distributions, and establish existing sympatry patterns.     

Bioventing of No. 2 Fuel Oil: Effects of Air Flowrate,Temperature, Nutrient Amendment,and Acclimation

A 14‐month pilot‐scale bioventing study, sponsored by the New Hampshire Department of Environmental Services, was conducted by the University of New Hampshire to determine the effects of the time between the contamination event and the onset of bioventing, as well as air flowrate, temperature, and nutrient amendments. Freshly contaminated soil was not readily amenable to bioventing. Bioventing was effective (82–92.5 percent removal) for acclimated soil amended with nutrients at 10 °C and 20 °C for the 275 cm³/min and 140 cm³/min air flowrates, respectively. First order degradation rates after nutrient addition were ?6.11 ± 0.83 (×10^?3)/day and ?6.57 ± 1.71 (×10^?3)/day, respectively. The results indicate that bioventing will be best applied when the contamination has occurred at least two years before the onset of treatment. © 2014 Wiley Periodicals, Inc.     

Metal availability in a highly contaminated, dredged-sediment disposal site: Field measurements and geochemical modeling

Two complementary approaches were used to characterize arsenic and metal mobilizations from a dredged-sediment disposal site: a detailed field study combined with hydrogeochemical modeling. Contaminants in sediments were found to be mainly present as sulfides subject to oxidation. Secondary phases (carbonates, sulfates, (hydr)oxides) were also observed. Oxidative processes occurred at different rates depending on physicochemical conditions and contaminant contents in the sediment. Two distinct areas were identified on the site, each corresponding to a specific contaminant mobility behavior. In a reducing area, Fe and As were highly soluble and illustrated anoxic behavior. In well-oxygenated material, groundwater was highly contaminated in Zn, Cd and Pb. A third zone in which sediments and groundwater were less contaminated was also characterized. This study enabled us to prioritize remediation work, which should aim to limit infiltration and long-term environmental impact.     

Variations in Epilimnion Thickness in Small Boreal Shield Lakes: Relationships with Transparency, Weather and Acidification

We used multiple linear regression analysis to investigate relationships between late-summer epilimnion thickness, transparency, lake area, acidity and summer weather conditions in a large ($n = 116$) multi-year data set for 9 small Boreal Shield lakes. Dissolved organic carbon (DOC) was the best individual predictor of late summer epilimnion thickness ($r^{2} = 0.69$). Total chlorophyll~$a$, the number of days between ice-out and late-summer stratification, and lake area collectively explained an additional 14% of the variation in epilimnion thickness. The three attributes of summer weather that we examined, mean daily temperature, mean daily wind speed, and mean daily hours of bright sunshine, did not add to the predictive ability of our regression model. Lake acidity also did not add directly to the predictive ability of the model, likely because DOC concentrations already reflected the effects of pH. Our study supports an increasing body of evidence indicating that the dominant effects of climate change on lake thermal structure in small lakes will be through effects on processes that affect lake transparency.     

Cellular response of mouse splenocytes to heavy metals exposure

Among the environmental contaminants recognised for their toxicity and their global presence, heavy metals are certainly a major concern. They can elicit a number of immunomodulatory effects leading ultimately to an enhanced susceptibility (sensitivity) of immune cells to microbial agents and the appearance of neoplastic diseases and autoimmune phenomena. Heavy metals also provoke changes in the function(s) of immune cells. A striking biological effect of heavy metals is the induction of intracellular thiols (cysteine, glutathione, metallothioneins). Thiols are involved in many physiological processes, including protection from free radical damage and detoxification of chemicals. The purpose of this study was to assess the differences of susceptibility (sensitivity) in both pre-activated (concanavalin A was used) and non-pre-activated cells in the presence of heavy metals. Five were evaluated on murine splenocytes. The lymphoblastic proliferation test was performed for lymphocytes and a phagocytosis test for macrophages. Data showed that the levels of thiols in the pre-activated cells are greater than non-pre-activated cells following exposure to various heavy metals; macrophages were more resistant than lymphocytes to the toxic effects of heavy metals, and pre-activated cells were more resistant than cells at rest. One possible explanation is that macrophages produce more thiols than lymphocytes and this provides an increased protection from the deleterious effects of heavy metals.     

Temperature, salinity and growth rate dependences of Mg/Ca and Sr/Ca ratios of the skeleton of the sea urchin Paracentrotus lividus (Lamarck): an experimental approach

The skeletal Mg/Ca ratio of echinoderms is known to increase with temperature but the relation has never been established in controlled experimental conditions. The present study investigated the effect of temperature, salinity and growth rate on Mg/Ca and Sr/Ca ratios in calcite skeletons of juvenile sea urchins grown in experimental conditions. Mg/Ca ratio was positively related to temperature, increasing until a plateau at high but field occurring temperatures. It was not linked to salinity nor growth rate. We suggest that this plateau is due to properties of the organic matrix of mineralization and recommend to take it into account for the use of Mg/Ca as proxy of seawater Mg/Ca. Skeletal Sr/Ca ratio was mainly dependent on temperature and growth rate, as usually observed in calcite skeletons.     

Combining chemical sequential extractions with 3D fluorescence spectroscopy to characterize sludge organic matter

The design and management of anaerobic digestion of sewage sludge (SS) require a relevant characterisation of the sludge organic matter (OM). Methods currently used are time-consuming and often insufficiently informative. A new method combining chemical sequential extractions (CSE) with 3D fluorescence spectroscopy was developed to provide a relevant SS characterisation to assess both OM bioaccessibility and complexity which govern SS biodegradability. CSE fractionates the sludge OM into 5 compartments of decreasing accessibility. First applied on three SS samples with different OM stability, fractionation profiles obtained were in accordance with the latter. 3D fluorescence spectroscopy revealed that the bioaccessible compartments were mainly constituted of simple and easily biodegradable OM while the unaccessible ones were largely made of complex and refractory OM. Then, primary, secondary and anaerobically digested sludge with different biodegradabilities were tested. Complexity revealed by 3D fluorescence spectroscopy was linked with biodegradability and chemical accessibility was correlated with sludge bioaccessibility.     

Evaluating the effects of foraging habitat restoration on shorebird reproduction: the importance of performance criteria and comparative design

Coastal development and engineering projects preclude ecosystem processes that provide habitat for beach nesting birds. Management for coastal species may depend on actions that attempt to restore important habitat features and mitigate disturbance effects. However, species response to restoration or other management actions may be difficult to predict or measure. At Jones Beach State Park, on Long Island, New York, a 0.49 ha restoration project provided moist substrate foraging habitat for breeding Piping Plovers (Charadrius melodus) from 2002 to 2005. We examined whether foraging habitat restoration affected Piping Plover breeding population size, productivity, and fledgling production within 300 m of the restoration site. We found a positive relationship between habitat restoration and the number of fledglings produced per year. However, foraging habitat restoration did not significantly increase the number of Plover pairs breeding at Jones Beach. Our ability to evaluate restoration effects on Plovers depended on: 1) use of multiple performance criteria; 2) a design that allowed comparison of pre- and post-restoration data; and 3) a spatial control that allowed comparison of similar areas that were near and far from the restoration site. Despite the small size of the restoration project, there were measurable benefits to Plovers, indicating that foraging habitat restoration may be an effective tool for species recovery.     

Introduction to the Featured Collection on “Nonstationarity,Hydrologic Frequency Analysis,and Water Management”1

Kiang, Julie E., J. Rolf Olsen, and Reagan M. Waskom, 2011. Introduction to the Featured Collection on “Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”Journal of the American Water Resources Association (JAWRA) 47(3):433‐435. DOI: 10.1111/j.1752‐1688.2011.00551.x