bluuebunny/crossref_metadata_2025 huggingface dataset:
Recommendations for the Selection, Stabilization, and Compaction of Soil for Rammed Earth Wall Construction
Authors: Burroughs Steve
Published: March 2010

Rammed earth possesses environmental advantages over most other competing construction materials. However, if it is to be more routinely used in the construction of modern, sustainable buildings, its material properties and production processes must be properly quantified. This paper proposes practical recommendations for soil selection, stabilizer treatment, and on-site compaction for rammed earth, based on a recent set of 219 stabilization experiments. The purpose of the recommendations is to maximize the probability of constructing rammed earth walls that meet or exceed a compressive strength criterion of 2 MPa. The recommendations cover: (1) Quantifying the natural soil properties of linear shrinkage and texture in a staged sequence in order to identify suitable soils to stabilize (and to reject unsuitable soils); (2) Quantifying the amounts of cement and/or lime to be added to the selected soil according to the values of soil properties measured; and (3) Quantifying the forces involved in on-site compaction of stabilized soil (for both manual and pneumatic ramming), and relating these to laboratory-based test standards. Although the recommendations need to be tested and verified/refined using new data, their initial application to rammed earth construction situations in Australia indicates that they have predictive utility. Further research will also indicate the degree of applicability of the recommendations to the production of compressed earth bricks.
An Analysis of LEED and BREEAM Assessment Methods for Educational Institutions
Authors: Reed Tracie J , Clouston Peggi L , Hoque Simi , Fisette Paul R
Published: March 2010

This study examines the differences between two environmental assessment methods for the K-12 education sector: the United States Green Building Council's (USGBC) LEED Schools Version 3.0 and the British Research Establishment's (BRE) BREEAM Education issue 2.0. Credit requirements are compared side-by-side and against recommendations from researchers in areas such as acoustics, lighting and indoor environment quality. Strengths in the two schemes and areas for improvement are highlighted, with acknowledgement that each scheme offers components and techniques from which the other could benefit.
Immunotherapy Can Reject Intracranial Tumor Cells without Damaging the Brain despite Sharing the Target Antigen
Authors: Bridle Byram W. , Li Jian , Jiang Shucui , Chang Ruby , Lichty Brian D. , Bramson Jonathan L. , Wan Yonghong
Published: March 2010

Although vaccines targeting tissue differentiation Ags represent a promising strategy for cancer immunotherapy, the risk of triggering autoimmune damage to normal tissues remains to be determined. Immunizing against a melanoma-associated Ag, dopachrome tautomerase (DCT), which normal melanocytes and glial cells also express, allowed concurrent analysis of autoimmune consequences in multiple tissues. We show that vaccination with recombinant adenovirus expressing DCT elicited a strong CTL response in C57BL/6 mice, leading to protection against intracranial challenge with B16-F10 melanoma cells. Both histological analysis and behavioral testing indicated that there was no evidence of neuropathology in vaccinated animals and long-term survivors. Although vitiligo or demyelination could be induced by additional stimuli (i.e., surgery or inflammation) in DCT-vaccinated mice, it did not extend beyond the inflammatory area, suggesting that there is self-regulatory negative feedback in normal tissues. These results demonstrate that it is possible to vaccinate against a tumor embedded in a vital organ that shares the target Ag.
An Autoimmune Response to Odorant Binding Protein 1a Is Associated with Dry Eye in the Aire-Deficient Mouse
Authors: DeVoss Jason J. , LeClair Norbert P. , Hou Yafei , Grewal Navdeep K. , Johannes Kellsey P. , Lu Wen , Yang Ting , Meagher Craig , Fong Lawrence , Strauss Erich C. , Anderson Mark S.
Published: March 2010

Sjögren’s Syndrome (SS) is a human autoimmune disease characterized by immune-mediated destruction of the lacrimal and salivary glands. In this study, we show that the Aire-deficient mouse represents a new tool to investigate autoimmune dacryoadenitis and keratoconjunctivitis sicca, features of SS. Previous work in the Aire-deficient mouse suggested a role for α-fodrin, a ubiquitous Ag, in the disease process. Using an unbiased biochemical approach, however, we have identified a novel lacrimal gland autoantigen, odorant binding protein 1a, targeted by the autoimmune response. This novel autoantigen is expressed in the thymus in an Aire-dependent manner. The results from our study suggest that defects in central tolerance may contribute to SS and provide a new and clinically relevant model to investigate the pathogenic mechanisms in lacrimal gland autoimmunity and associated ocular surface sequelae.
Adoptive Transfer of Tumor-Specific Tc17 Effector T Cells Controls the Growth of B16 Melanoma in Mice
Authors: Garcia-Hernandez Maria de la Luz , Hamada Hiromasa , Reome Joyce B. , Misra Sara K. , Tighe Michael P. , Dutton Richard W.
Published: March 2010

In vitro generated OVA-specific IL-17–producing CD8 T effector cells (Tc17) from OT-1 mice, adoptively transferred into B16-OVA tumor-bearing mice, controlled tumor growth in early and late stage melanoma. IL-17, TNF, and IFN-γ from the Tc17 effectors all played a role in an enhanced recruitment of T cells, neutrophils, and macrophages to the tumor. In addition, Tc17 cells and recently recruited, activated neutrophils produced further chemokines, including CCL3, CCL4, CCL5, CXCL9, and CXCL10, responsible for the attraction of type 1 lymphocytes (Th1 and Tc1) and additional neutrophils. Neutrophils were rapidly attracted to the tumor site by an IL-17 dependent mechanism, but at later stages the induction of the chemokine CXCL2 by Tc17-derived TNF and IFN-γ contributed to sustain neutrophil recruitment. Approximately 10–50 times as many Tc17 effectors were required compared with Tc1 effectors to exert the same level of control over tumor growth. The recruitment of neutrophils was more prominent when Tc17 rather than Tc1 were used to control tumor and depletion of neutrophils resulted in a diminished capacity to control tumor growth.
Robotically-Assisted Coronary Artery Bypass Grafting
Authors: Folliguet Thierry A. , Dibie Alain , Philippe François , Larrazet Fabrice , Slama Michel S. , Laborde François
Published: March 2010

Objectives. Robotic surgery enables to perform coronary surgery totally endoscopically. This report describes our experience using the da Vinci system for coronary artery bypass surgery.Methods. Patients requiring single-or-double vessel revascularization were eligible. The procedure was performed without cardiopulmonary bypass on a beating heart.Results. From April 2004 to May 2008, fifty-six patients were enrolled in the study. Twenty-four patients underwent robotic harvesting of the mammary conduit followed by minimal invasive direct coronary artery bypass (MIDCAB), and twenty-three patients had a totally endoscopic coronary artery bypass (TECAB) grafting. Nine patients (16%) were converted to open techniques. The mean total operating time for TECAB was minutes and for MIDCAB was minutes. Followup was complete for all patients up to one year. There was one hospital death following MIDCAB and two deaths at follow up. Forty-eight patients had an angiogram or CT scan revealing occlusion or anastomotic stenoses (>50%) in 6 patients. Overall permeability was 92%.Conclusions. Robotic surgery can be performed with promising results.
Influence of the Sanitary Landfill of São Carlos (SP), Brazil, in Superficial and Ground Water Quality
Authors: Lopes Adriana Antunes , Brigante J. , Schalch V.
Published: March 2010

Few works have assessed the water toxicity caused by leachate from urban landfills. The present study evaluated the superficial and groundwater quality around the urban landfill of São Carlos (SP), Brazil, using physical-chemistries analyses and acute and chronic toxicity with Ceriodaphnia silvestrii. In 2004, four water samples were collected during two fieldworks in the Galdino Stream (one site before and three after the landfill). The superficial water samples did not present any toxicity effect, while the well samples showed high values for some parameters and acute toxicity (p < 0.05) in all samples. In the first fieldwork, samples from the well before and after the landfill showed immobility of 50% and 100%, respectively. In the second fieldwork, samples from the well before the landfill caused immobility of 45% and presented chronic toxicity, while the wells after caused immobility of 100%. Thus, the results pointed out that the leachate is probably percolation and affecting the water quality of the groundwater.
Erratum to Avaliação das Atividades Tóxicas e Mutagênicas da Água e do Sedimento do Arroio Estância Velha, Região Coureira Calçadista, Utilizando Allium cepa
Authors: Mitteregger-Júnior Horst , Ferraz-Dias J. , Lúcia-Yonema M. , Arenzon A. , Silva J. , Pegas-Henriques J. A.
Published: March 2010

Erratum to Avaliação das Atividades Tóxicas e Mutagênicas da Água e do Sedimento do Arroio Estância Velha, Região Coureira Calçadista, Utilizando Allium cepa
Determination of conditional stability constants of cadmium-humic acid complexes in freshwater by use of a competitive ligand equilibration-solvent extraction technique
Authors: Van Ginneken Luc , Blust Ronny
Published: March 2010

A technique for determining organic complexation of cadmium in freshwater using competitive ligand equilibration coupled with solvent extraction was evaluated. The method involves a competitive equilibration of the sample with potassium iodide and pyridine followed by extraction of the mixed cadmium-iodide-pyridine complex into a benzene phase. The final distribution of the metal is measured by gamma ray spectrometry. The method's suitability was verified by performing extractions on the model ligand 8-hydroxyquinoline-5-sulfonic acid (sulfoxine), which forms well-characterized complexes with cadmium. The speciation results so obtained were in excellent agreement with results calculated with a chemical speciation model. The method was applied to study complexation of cadmium with two commercially available humic acids in reconstituted freshwater at relatively high cadmium concentrations to mimic polluted freshwaters. The obtained titration data were fitted to a one-site Langmuir adsorption model, yielding values of 106.59 and 106.52 for the respective conditional stability constants, and 0.57 and 0.90 μM for the respective ligand concentrations.
A test of the community conditioning hypothesis: Persistence of effects in model ecological structures dosed with the jet fuel jp-8
Authors: Landis Wayne G , Markiewicz April J , Matthews Robin A , Matthews Geoffrey B
Published: March 2010

The foundation of the community conditioning hypothesis, the persistence of effects, was tested in a series of microcosm experiments. Experiments were conducted with the water-soluble fraction of the turbine fuel JP-8 using the standard protocols for the standardized aquatic microcosm (SAM). A repeat trial was conducted using the SAM protocol but with a 126-d test period, twice the standard duration. The results were examined using a variety of conventional univariate, multivariate, and graphical techniques. The principal conclusions were as follows. Effects are persistent in these model ecological systems long after the degradation of the toxicant. Patterns of impacts are detectable at concentrations 15 times lower than an experimentally derived single-species EC50. The replicate experiments are not replicable in the specific, but the broad pattern of the disruption of algal- herbivore dynamics followed by more subtle effects are consistently repeated. The durability of the indirect effects and therefore the information about historical events appears to be a consistent feature of these microcosm systems. The identity of the treatment groups persists. The critical features of the community conditioning hypothesis—persistence of information within ecologicalsystems and the reappearance of patterns and therefore the nonequilibrium dynamics—are again confirmed. The implications of these findings for environmental toxicology, monitoring, and ecological risk assessment are discussed.
Response of Daphnia magna to pulsed exposures of chlorpyrifos
Authors: Naddy Rami B , Johnson Kevin A , Klaine Stephen J
Published: March 2010

Because aquatic organisms can be exposed to contaminants in an episodic manner, it is necessary to determine whether standard toxicity tests adequately simulate the toxicity of short-lived compounds, such as the organophosphate insecticide chlorpyrifos (CPF). We conducted experiments to evaluate the effect of binary combinations of concentration, duration, and interval of CPF exposures to Daphnia magna. Organisms were monitored for changes in survival and/or reproduction after pulsed exposure to CPF at 0.12, 0.25, 0.5, or 1.0 μg/L. The exposure duration resulting in a 50% response in survival was 6.5 h at 1.0 μg/L, 12.2 h at 0.5 μg/L, and 48 h at 0.25 μg/L. Daphnids exposed to two 12-h pulses of CPF at 0.5 μg/L responded similarly (≥85% mortality) regardless of the pulse interval (0, 3, 7, 14 d). However, daphnids were able to survive a 12-h exposure of CPF at 0.5 μg/L if the exposure regime was separated into two 6-h pulses with a minimum interval of 3 d. Further experiments suggested that the interval studies may have been potentially confounded, because organisms exposed on day 3, 7, or 14 seemed more sensitive than those exposed as neonates. Additionally, no latent effects were measured for daphnids that survived the initial exposure.
Reproduction of cavity-nesting birds in pesticide-sprayed apple orchards in southern Ontario, Canada, 1988–1994
Authors: Bishop Christine A , Collins Brian , Mineau Pierre , Burgess Neil M , Read William F , Risley Chris
Published: March 2010

Egg fertility, clutch size andeggandchick survival and pesticideexposureof tree swallows (Tachycineta bicolor) and eastern bluebirds (Sialia sialis) were measured annually using nest boxes in sprayed and nonsprayed apple orchards in southern Ontario, Canada, during 1988–1994. Associations were examined between reproductive rates and historical organochlorine residues in eggs as well as the degree of exposure and toxicity of pesticides applied during the study period. Because many pesticides in current use are not persistent in wildlife tissues, a toxicity score was developed to describe the exposure for each nest. The toxicity score was calculated as the product of the extent of the orchard sprayed and the application rate of the chemicals, divided by an acute reproductive toxicity index of each chemical. Total organochlorine concentrations in tree swallow eggs were 0.74 to 3.47 μg/g, and in eastern bluebird eggs, these values ranged from 0.47 to 106.3 μg/g. More than 90% of the residue in eggs was pp′DDE. There was a significant increase in unhatched eggs in bluebirds as organochlorine levels increased in eggs. There were significant associations between toxicity scores of current-use pesticides and at least one avian reproductive parameter in every year of the study, but the reduction in reproductive rates associated with pesticides did not exceed 14%, for either species, in any year. Reduced reproduction occurred in 6 years in tree swallows but for bluebirds, this occurred in only 4 years.
Effects of the mosquito larvicides temephos and methoprene on insect populations in experimental ponds
Authors: Pinkney Alfred E , McGowan Peter C , Murphy Daniel R , Lowe T Peter , Sparling Donald W , Ferrington Leonard C
Published: March 2010

The nontarget effects of Abate® 4E (44.6% temephos) at 0.054 kg of active ingredient (a.i.) per 1 ha and of Altosid® Liquid Larvicide (5% methoprene) at 0.011 kg a.i./ha were investigated in 18 experimental ponds (average area, 202 m2; maximum depth, 0.7 m) at Patuxent Wildlife Research Center, Laurel, Maryland, USA. Ponds were sprayed three times at 3-week intervals. Six ponds were sprayed with Abate, six with Altosid, and six with distilled water. Two insect-emergence traps per pond collected for 7 d and were then harvested 1 d before each spray and 13 to 14 days afterward. A repeated measures analysis of variance (ANOVA) revealed significant reductions in Shannon diversity, equitability, and numbers of individuals, species, and families in the Abate ponds relative to controls. Significant reductions also occurred in Ephemeroptera, Odonata, Diptera, Chironomidae, and Chaoborus sp. Hester-Dendy samplers were installed before spray one and harvested 16 d after spray three. Based on one-way ANOVA, Shannon diversity, equitability, and number of Ephemeroptera and Chironomidae were significantly reduced in the Abate ponds. Emergence data indicate only isolated cases with significant reductions in the Altosid ponds relative to controls, and the Hester-Dendy data indicate no significant differences between the Altosid and control ponds.
Changes in cytochrome P4501A activity during development in common tern chicks fed polychlorinated biphenyls, as measured by the caffeine breath test
Authors: Feyk Lori A , Giesy John P. , Bosveld Albertus T C , van den Berg Martin
Published: March 2010

Cytochrome P4501A (CYP1A) activity is often used as a biomarker of exposure of wildlife to polyhalogenated diaromatic hydrocarbons and is usually measured ex vivo in liver tissue. A caffeine breath test (CBT) with radiolabeled substrate (14C-caffeine) was used to measure in vivo CYP1A activity twice during development in 14 common tern (Sterna hirundo) chicks treated with polyhalogenated diaromatic hydrocarbons. Tern hatchlings were fed fish spiked with 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153) such that the diet contained an average of 23, 99, or 561 pg of 2,3,7,8-tetra-chlorodibenzo-p-dioxin equivalents per gram offish for 21 d. Sixteen additional common tern chicks were similarly dosed with polyhalogenated diaromatic hydrocarbons but were not subjected to the CBT procedure. In weeks 1 and 2, caffeine N-demethylation and ethoxyresorufin-O-deethylation activity on day 21 were elevated in birds that received the greatest PCB dose. There was less constitutive and greater induction of ethoxyresorufin-O-deethylation activity than caffeine N-demethylation. The 14C-CBT was less invasive than the ethoxyresorufin-O-deethylase assay. Only one morphological parameter differed significantly between CBT subjects and no-CBT subjects fed the same level of PCBs. Bursa weight was significantly less in control CBT subjects than in control no-CBT subjects, but bursa weights did not differ among CBT and no-CBT birds from the two PCB treatment groups. No alterations of survival or growth occurred in CBT subjects compared with no-CBT subjects.
Effects of storage on the toxicity of sediments spiked with fluoranthene to the amphipod, Rhepoxynius abronius
Authors: Cole Faith A , Boese Bruce L , Swartz Richard C , Lamberson Janet O , DeWitt Theodore H
Published: March 2010

To determine the effect of storage on contaminant bioavailability and toxicity, two sedimenttypes, a fine sand and a silty sand, were spiked with nine concentrations of fluoranthene (0.0–50 mg/dry kg) then stored at 4°C for up to 170 d. Toxicity of the stored sediment was determined eight times during this storage interval using standard 10-d toxicity tests with the marine infaunal amphipod Rhepoxynius abronius. The concentrations of fluoranthene in the sediment and interstitial water were determined on samples taken on each test date. The toxicity of fluoranthene in the silty sand was similar for all storage times with LC50s ranging from 5.3 to 6.6 mg/g organic carbon (OC). The LC50 in the fine sand was 7.4 mg/g OC after 13 d of storage, ranged from 10.2 to 11.8 mg/g OC during 27 to 83 d of storage, and increased to 24.2 and 27.6 mg/g OC after 121 and 170 d of storage, respectively. These data indicate that the toxicity of both the fine and the silty sand remained essentially constant during storage from days 27 to 83. Toxicity tests conducted before or after that period may give misleading results because of disequilibrium or unknown storage effects.
Distribution of degradation products of alkylphenol ethoxylates near sewage treatment plants in the lower Great Lakes, North America
Authors: Bennett Erin R , Metcalfe Chris D
Published: March 2010

Degradation of alkylphenol ethoxylate (APEO) surfactants in the environment leads to the formation of relatively hydrophobic compounds such as nonylphenol (NP), octylphenol (OP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) that have been shown to have estrogenic activity. Previous studies have shown that sewage treatment plants (STPs) are point sources for these compounds in the aquatic environment. We collected sediment samples at several sites in the vicinity of STPs in Hamilton Harbour and in the Detroit River to determine the spatial distribution of the degradation products of APEOs. In addition, we deployed semipermeable membrane devices (SPMDs) and caged freshwater mussels (Elliptio complanata) at these locations to determine the distribution of these compounds in the dissolved phase and their potential to bioaccumulate in aquatic organisms. The NP, OP, NP1EO, and NP2EO were found at μg/g (dry wt.) concentrations in sediments and accumulated to ng/g (wet wt.) concentrations in caged mussels near the STPs. However, in the Detroit River, the concentrations of these compounds declined to near background levels in the sediments, water column (i.e., SPMDs), and biota at stations about 1 km downstream from STPs. At stations in Hamilton Harbour, concentrations of APEO degradation products also declined markedly in sediments and SPMDs located a few hundred meters from the STP. These data indicate that degradation products of APEOs can be accumulated by biota near STPs. However, the environmental distribution of these compounds is localized to areas close to the point of discharge.
Effects of acute exposure to fluoranthene-contaminated sediment on the survival and genetic variability of fathead minnows (Pimephales promelas)
Authors: Schlueter Mark A , Guttman Sheldon I , Duan Yihao , Oris James T , Huang Xiaodong , Burton G Allen
Published: March 2010

One-month-old fathead minnows (Pimephales promelas) were exposed to fluoranthene-contaminated sediment (1.24 mg/gm organic carbon) during a 96-h exposure. Of the 909 minnows exposed to fluoranthene, 684 (75%) minnows died during the exposure. Horizontal starch-gel electrophoresis was used to determine genotypes at six variable enzyme loci (β-GAL*, GPI-1*, GPI-2*, IDHP-1*, MDH-2*, and PGM*). Statistical analyses were used to evaluate the relationships between the genetic data and weight, length, and time to death (TTD) offish using an accelerated failure time regression model (LIFEREG). The GPI-1*, MDH-2*, and PGM* loci were found to be significantly related to TTD. Multilocus heterozygosity was also related to TTD. Lower heterozygosity was related to a longer TTD and a greater chance of survival. Fish weight was strongly related to TTD and survival. Larger fish had a longer TTD and a greater chance of survival. Mean fish weight differed significantly among genotypes at each locus. This resulted in large differences between LIFEREG regression models that factored weight out and those models that did not separate weight from the genotypes or multilocus heterozygosity. The results of the study indicated that differential survival to fluoranthene was genetically related. The frequencies of several genotypes were significantly different in the survivors of the fluoranthene exposure compared with those in the initial population.
Ecological research in the office of research and development at the U.S. Environmental Protection Agency: An overview of new directions
Authors: Linthurst Rick A , Mulkey Lee A , Slimak Michael W , Veith Gilman D , Levinson Barbara M
Published: March 2010

In virtually every major environmental act, Congress has required that the U.S. Environmental Protection Agency (U.S. EPA) ensure not only that the air be safe to breathe, the water safe to drink, and the food supply free of contamination, but also that the environment be protected. In response, the U.S. EPA's Office of Research and Development (ORD) has established research to improve ecosystem risk assessment and management, identifying it as one of the highest priority research areas for investment over the next 10 years. The research is intended to provide environmental managers with new tools and flexible guidance that reflect a holistic environmental management perspective of science and that can be applied both to common and unique problems. In keeping with its responsibility to provide the U.S. EPA with science that supports a dynamic changing regulatory agenda, the ORD has set the goal of its Ecological Research Program to “provide the scientific understanding required to measure, model, maintain and/or restore, at multiple scales, the integrity and sustainability of ecosystems now, and in the future.” In the context of this program, ecological integrity is defined in relative terms as the maintenance of ecosystem structure and function characteristic of a reference condition deemed appropriate for its use by society, and sustainability is defined as the ability of an ecosystem to maintain relative ecological integrity into the future. Therefore, the research program will emphasize relative risk and consider the impact of multiple stressors, at multiple scales and at multiple levels of biological organization. The program will also shift from chemical to biological and physical stressors to a far greater extent than in the past. The purpose of this paper is to provide an introduction to the U.S. EPA's changing ecological research program.
Biological activity associated with noncoplanar polychlorinated biphenyls after microbial dechlorination of aroclor 1242® and aroclor 1254®
Authors: Ganey Patricia E , Quensen John F , Mousa Mahmoud A , Boyd Stephen A , Wagner Margaret A , Fischer Lawrence J
Published: March 2010

Bioremediation of polychlorinated biphenyls (PCBs) byanaerobic microbial dechlorination occurring naturally in the subsurface and in engineered systems results in mixtures of lower-chlorinated, primarily ortho-substituted biphenyls. The purpose of this study was to determine whether this process of bacterial dechlorination results in a mixture that differs in biological activity from that of the parent PCB mixture. Two biological assays sensitive to the action of ortho-substituted PCBs were employed: insulin release by RINm5F cells, and superoxide anion (O2) production by rat neutrophils. The PCB mixtures Aroclor 1242® and Aroclor 1254® were incubated for nine months with microbes from PCB-contaminated sites (Silver Lake, MA, USA, or River Raisin, MI, USA), and the products of dechlorination were then extracted. Exposure of RINm5F cells to dechlorinated Aroclor 1242 or 1254 product mixtures caused an increase in insulin release similar to the hormone release from cells exposed to non-dechlorinated Aroclors. When tested alone, several of the major products identified in the dechlorination mixture (i.e., 2,2′,4,4′-tetrachlorobiphenyl, 2,2′,4-trichlorobiphenyl [TCB], 2,3′,4-TCB, 2,3′,5-TCB, and 2,2′-dichlorobiphenyl) caused an increase in insulin release. In studies using neutrophils isolated from rat peritoneum, the amount of O2 produced on exposure to product mixtures resulting from dechlorination of Aroclor 1242 was not different from the amount produced in nondechlorinated controls. The product mixture resulting from Aroclor 1254 dechlorination by organisms from River Raisin increased generation of O2− relative to the parent Aroclor. Taken together, these results suggest that anaerobic dechlorination of Aroclor mixtures of PCBs does not reduce the biological activities associated with lightly chlorinated and ortho-substituted PCBs. This observation has implications for the usefulness of PCB bioremediation efforts that involve only anaerobic dechlorination.
Differences in the sensitivity of benthic microalgae to ZN and CD regarding biofilm development and exposure history
Authors: Ivorra Núria , Bremer Simone , Guasch Helena , Kraak Michiel HS , Admiraal Wim
Published: March 2010

Microbenthic biofilms are consortia of autotrophic and heterotrophic organisms imbedded in a matrix of polymers and particles. As biofilms develop, internal cycling of materials might predominate, and dependence on external conditions is reduced. The mature biofilm structure may act as a barrier against deleterious effects of metals on microphytobenthos. To validate this hypothesis, biofilms from two lowland streams near the Dutch-Belgian border, the extremely Zn- and Cd-polluted Eindergatloop and the relatively clean Keersop in the River Dommel subsystem, were collected after 2 weeks (young) and 6 weeks (old) of colonization. Young and old biofilms from both sites were subsequently exposed in the laboratory to Zn and Cd concentrations mimicking that of the heavily polluted stream for a period of 2 weeks. Diatom composition, chlorophyll a, total carbohydrates, Zn and Cd concentrations, minimal chlorophyll fluorescence, and photon yield demonstrated more pronounced metal effects on the young than on the old reference biofilms. In contrast, colonization time had less effect on the overall response of the extremely polluted biofilms. Therefore, biofilms in an early colonization stage are more vulnerable than mature biofilms to metal exposure, and exposure history determines the response of biofilms to metals.
Chlorinated hydrocarbons in flatfishes from the Southern California, USA, Bight
Authors: Schiff Kenneth , Allen M James
Published: March 2010

Alhough inputs of chlorinated hydrocarbon compounds to the Southern California Bight (SCB) are presently low, historical deposits represent a source of bioaccumulation potential to sediment-associated fauna. To assess this bioaccumulation potential, 14 chlorinated hydrocarbon classes were measured in livers of three species of flatfish collected from 63 randomly selected sites on the coastal shelf between Point Conception and the United States–Mexico international border. Tissue contamination was widespread throughout the SCB, but was limited to just two chlorinated hydrocarbon classes. Virtually 100% of Pacific sanddab (Citharichthys sordidus) and longfin sanddab (Citharichthys xanthostigma) populations were estimated to be contaminated with dichlorodiphenyltrichloroethane (total DDT = sum of o,p′ and p,p′ isomers of DDT + dichlorodiphenyldichloroethylene [DDE] + dichlorodiphenyldichloroethane [DDD]) and/or polychlorinated biphenyls (total PCBs). Total DDT also contaminated the majority (64%) of the Dover sole (Microstomus pacificus) population in the SCB. Total PCB measurements in tissues of SCB flatfish were dominated by 12 congeners (52, 66, 87, 101, 105, 118, 128, 138, 153, 170, 180, and 187), which averaged 95% of the combined mass of the 27 congeners analyzed. Sediment concentrations (normalized by total organic carbon content) accounted for most of the variability observed in tissue concentrations (normalized by lipid content) for 8 of these 12 congeners and total PCBs. Normalized sediment concentrations were also significantly correlated to normalized tissue concentrations for total DDT and p,p′-DDE. Tissue concentrations measured in this study from reference areas of the SCB were compared to tissue concentrations measured from reference areas in studies conducted in 1977 and 1985. Total DDT and total PCB liver concentrations were found to have decreased one to two orders of magnitude in Pacific and longfin sanddabs between 1985 and 1994. Total DDT and total PCB liver concentrations decreased 5- to 35-fold in Dover sole between 1977 and 1994.
An in vitro assessment of the toxicity of 2,4-dichloroaniline using rainbow trout primary epidermal cell cultures
Authors: Kilemade Michael , Mothersill Carmel
Published: March 2010

2,4-Dichloroaniline (2,4-DCA) is a common pollutant of freshwaters. Information on the effects of this chemical on the aquatic environment is lacking. In this work, we present a technique using primary cell culture of rainbow trout (Oncorhynchus mykiss) epidermal cells as a model for the evaluation of the potential ecotoxicologic hazards of 2,4-DCA. The effects of a wide dose range of the chemical on survival and function of the cells were studied. 2,4-Dichloroaniline was found to show an increasingly toxic effect over the dose range of 100 to 1,000 μM. The toxicity threshold was observed to occur at approximately 400 μM in serum-containing media and 200 μM in serum-free media. The LC50 in serum-containing media at 24, 48, 72, and 96 h of exposure ranged from 650 to 740 μM. In serum-free media the LC50 ranged from 340 to 500 μM over a similar time period. Therefore, the toxicity of 2,4-DCA to the primary cells increased in the absence of serum in the culture medium. As the 2,4-DCA concentration increased the number of goblet (mucus) cells present in the cultures decreased, as did the normal healthy epidermal cells. Cell death was predominantly necrotic as opposed to apoptotic. This study is the first demonstration of an in vitro technique using fish primary epidermal cultures as a toxicology assessment tool. The major advantage of using primary cultures as opposed to immortalized cell lines is in the ability of these cultures to maintain their in vivo characteristics for approximately 10 d postexposure, allowing the study of the acute effects of aquatic contaminants. The characteristics of established cells deviate substantially from those of normal cells.
Toward a mechanistic understanding of contaminant-induced changes in detritus processing in streams: Direct and indirect effects on detritivore feeding
Authors: Forrow David M , Maltby Lorraine
Published: March 2010

Macroinvertebrate feeding is a major rate-limiting step in the processing of detritus in streams. Environmental contaminants can reduce detritus processing by decreasing the abundance or feeding activity of detritivores. Contaminant-induced reductions in detritus processing can have important consequences for the structure and functioning of the stream community. Here we investigate the mechanistic basis for reduced leaf processing in a stream contaminated with motorway (superhighway) runoff. In situ and laboratory studies were used and the work focused on Gammarus pulex (Amphipoda), the dominant detritivore at the site. The in situ feeding rate of G. pulex was significantly reduced downstream of the motorway discharge. Reductions in feeding rate could be the result of contaminants in the discharge having a direct effect on the animal or the discharge may affect the animal's feeding indirectly, by reducing food quality. Food quality may be reduced by contaminant accumulation or changes in microbial conditioning. Laboratory studies demonstrated that the main mechanism responsible for the reduction in feeding was direct toxicity and that this was most severe when animals were in direct contact with contaminated sediments. Neither contaminant accumulation nor differences in microbial conditioning affected the choice or consumption of leaf material by G. pulex over short exposure periods (i.e., < 14 d). However, contaminant-induced reductions in microbial conditioning were important over longer exposure periods (i.e., ≥27 d).
Estimating and testing bioconcentration factors
Authors: Bailer A John , Walker Sean E , Venis Kyle J
Published: March 2010

Bioconcentration factors (BCFs) are commonly calculated to represent the equilibrium concentration of a substance in an organism relative to environmental concentrations of the same substance. The BCF is derived from parameters estimated in uptake and elimination experiments and is presented as a single value without error estimates or confidence intervals. However, it is desirable to know the variability/precision of the BCF estimate and to statistically compare BCFs among experimental conditions. In this study, the calculation of standard errors and confidence intervals for BCFs is presented. In addition, a statistical method for formally comparing the BCFs derived under two or more experimental conditions is discussed. These methods are illustrated using data from a study of DDT-exposed Hyalella azteca and Diporeia spp.
Developing a standard spiking procedure for the introduction of hydrophobic organic compounds into field-wet soil
Authors: Northcott Grant L , Jones Kevin C
Published: March 2010

The purpose of this study was to reevaluate a number of spiking procedures we had previously investigated for spiking dry soil, determine their suitability for spiking radiolabeled hydrophobic organic compounds in field-wet soil, and identify the optimal spiking procedure. In the first part of this study, two radiolabeled polycyclic aromatic hydrocarbons (PAHs), phenanthrene (Phe) and benzo[a]pyrene (BaP), were introduced into field-wet soil by four different spiking procedures and the recovery and homogeneity of compound distribution assessed by analysis of replicate subsamples. The identified optimal spiking procedure involved adding an acetone spike solution to 10 ml acetone in a blender base, adding 250 g field-wet soil, and mixing with a highspeed blender. The relative standard deviations obtained by this procedure were 2.7 and 5.3% for 14C-Phe and 14C-7-BαP, respectively, and were comparable to those we obtained in a previous study for spiking dry soil. The persistence of acetone used as a carrier solvent in the optimal spiking procedure was assessed at various times after spiking to identify a suitable equilibration time to allow for solvent volatilization. The equilibration time, together with the identified optimal spiking procedure, were combined to develop a standard spiking procedure. The standard spiking procedure was used to prepare multiple soil microcosms individually spiked with radiolabeled Phe, pyrene, and BaP for a long-term aging study on the formation of PAH-bound residues in arable soil. The mean spike activity and homogeneity of spike distribution in 54 sterilized microcosms (3 × 18) stored over 525 d was determined. Mean spike recovery and relative standard deviations (RSDs) for the three radiolabeled PAHs in the individually spiked and prepared microcosms were very good. However, this data illustrates the importance of determining the concentration and homogeneity of spikes within all individual test portions in experiments where organic compounds are spiked into soil or sediment.
Oral deformities in several species of frogs from the Savannah River Site, USA
Authors: Burger Joanna , Snodgrass Joel W
Published: March 2010

Tadpoles of seven species of frogs from 22 wetlands on the Savannah River Site in South Carolina, USA, were examined to assess the prevalence of mouth-part deformities and axial skeletal deformities. Species examined included southern toad (Bufo terrestris), pine woods treefrog (Hyla femoralis), spring peeper (Pseudacris crucifer), southern chorus frog (P. nigrita), ornate chorus frog (P. ornata), bronze frog (Rana clamitans), and southern leopard frog (R. utricularia). Of the 4,335 tadpoles examined in 1997 and 1998, 6% exhibited mouth-part deformities and none exhibited axial skeletal deformities. However, significant interspecific differences existed for both prehind-limb and posthind-limb developmental stages. The highest percentage of deformities in prehind-limb stage occurred in spring peeper (27%), ornate chorus frog (29%), and bronze frog (33%), and the lowest percentage occurred in southern toad (5.5%) and southern chorus frog (4.8%). The frequency of mouth deformities decreased from the prehind-to posthind-limb developmental stage for six of seven species and was significant for southern toad and ornate chorus frog. Differences existed in the percent of mouth-part deformities among species in the same wetland and among wetlands for two species (southern toad and southern leopard frog). Among southern toads, mouth-part deformities increased with increasing hydroperiod length. Oral deformities may lead to lowered feeding success and lowered survival of tadpoles, resulting in a lower percentage of deformities in the posthind-limb stage.
Analysis of estrogenic hormones in municipal wastewater effluent and surface water using enzyme-linked immunosorbent assay and gas chromatography/tandem mass spectrometry
Authors: Huang Ching-Hua , Sedlak David L
Published: March 2010

Ahough the estrogenichormones177β-estradiol and 17α-ethinyl estradiol can be quantified in polluted waters by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/tandem mass spectrometry (GC/MS/MS), the compounds often are present at concentrations below detection limits. Enzyme-linked immunosorbent assays (ELISAs) provide a sensitive and robust means of quantifying estrogenic hormones in wastewater effluents and surface waters. Results from ELISA analysis of estrogenic hormones in secondary wastewater effluent indicate concentrations comparable to those that cause vitellogenesis in fish. Confirmatory analyses by GC/MS/MS are consistent with ELISA results. Effluent filtration, using sand filtration or microfiltration, removes approx. 70% of the hormones from secondary effluent, while advanced treatment, using reverse osmosis, removes more than 95% of hormones. The detection limits for estrogenic hormones are approx. 0.1 ng/L in wastewater effluent and 0.05 ng/L in surface water. The ELISA technique provides a relatively simple and practical method of assessing the fate of estrogenic hormones in engineered and natural systems.
Developmental stage-specific life-cycle bioassay for assessment of sediment-associated toxicant effects on benthic copepod production
Authors: Chandler G Thomas , Green Andrew S
Published: March 2010

In chronic bioassays of sediment organic compounds, toxicant exposures often decline through time, such that the beginning of a test yields disproportionately higher exposures than the end. Thus, those life stages initiating a test often are exposed to the highest concentrations, and for rapidly maturing test fauna, this may lead to varying conclusions regarding compound toxicities depending on the initial life stage chosen. This problem can be addressed by comparative full life-cycle tests initiated with different test-organism life stages. Thus, a full life stage-to-life stage toxicity test was developed for the rapidly maturing meiobenthic copepod Amphiascus tenuiremis to assess the importance of developmental stage at the onset of sediment toxicant exposure relative to reproduction, net population growth, and sex and age structure. Tests were conducted with a model spiked-sediment insecticide, chlorpyrifos, for each of the major life stages (P1) of A. tenuiremis (nauplius, copepodite, and adult). Each P1 stage was allowed to mature and reproduce in low chlorpyrifos concentrations (6–33% of stage-specific 96-h LC50s; 4–22 ng chlorpyrifos/g dry sediment) for 26 d. Test endpoints were numbers of surviving adult females, males, eggs per female (clutch), first generation (F1) nauplii, F1 copepodites, F1 total production, and realized F1 production per surviving female. Only the copepodite P1 test showed a significant decline in survival of an adult age class: females declined by 28% at 22 ng/g. Reductions in total production ranged from 33–96% of controls from nauplius to adult. The P1 naupliar stage was most sensitive, with F1 production being 33–47% of that in controls. However, on a realized production per female basis, both the copepodite and naupliar P1 yielded significantly reduced F1S of 23 and 40% of controls at 11 and 22 ng/g.
Potential multidrug resistance gene POHL: An ecologically relevant indicator in marine sponges
Authors: Krasko Anatoli , Kurelec Branko , Batel Renato , Müller Isabel M , Müller Werner E G
Published: March 2010

Sponges are sessile filter feeders found in all aquatic habitats from the tropics to the arctic. Against potential environmental hazards, they are provided with efficient defense systems, e.g., protecting chaperones and/or the P-170/multidrug resistance pump system. Here we report on a further multidrug resistance pathway that is related to the pad one homologue (POH1) mechanism recently identified in humans. It is suggested that proteolysis is involved in the inactivation of xenobiotics by the POH1 system. Two cDNAs were cloned, one from the demosponge Geodia cydoniumand a second from the hexactinellid sponge Aphrocallistes vastus. The cDNA from G. cydonium, termed GCPOHL, encodes a deduced polypeptide with a size of 34,591 Da and that from A. vastus, AVPOHL, a protein of a calculated Mr of 34,282. The two sponge cDNAs are highly similar to each other as well as to the known sequences from fungi (Schizosaccharomyces pombe and Saccharomyces cerevisiae) and other Metazoa (from Schistosoma mansoni to humans). Under controlled laboratory conditions, the expression of the potential multidrug resistance gene POHL is, in G. cydonium, strongly upregulated in response to the toxins staurosporin (20 μM) or taxol (50 μM); the first detectable transcripts appear after 1 d and reach a maximum after 3 to 5 d of incubation. The relevance of the expression pattern of the G. cydonium gene POHL for the assessment of pollution in the field was determined at differently polluted sites in the area around Rovinj (Croatia; Mediterranean Sea, Adriatic Sea). The load of the selected sites was assessed by measuring the potency of XAD-7 concentrates of water samples taken from those places to induce the level of benzo[a]pyrene monooxygenase (BaPMO) in fish and to impair the multidrug resistance (MDR)/P-170 extrusion pump in clams. These field experiments revealed that the levels of inducible BaPMO activity in fish and of the MDR potential by the water concentrates are highly correlated with the level of expression of the potential multidrug resistance gene POHL in G. cydonium. This report demonstrates that the detoxification POH pathway, here mediated by the G. cydonium GCPOHL gene, is an additional marker for the assessment of the environmental load in a given marine area.
Stability of immobilized 2,4,6-trinitrotoluene metabolites in soil under long-term leaching conditions
Authors: Achtnich Christof , Lenke Hiltrud
Published: March 2010

2,4,6-Trinitrotoluene (TNT)-contaminated soil was remediated by an anaerobic/aerobic slurry process. Prior to treatment, the soil was spiked with [14C]-TNT. Leaching experiments were carried out with the decontaminated soil to determine the degree of binding of the radiolabel under a variety of conditions. To simulate natural degradation processes of soil organic matter, each of three columns was subjected to a different treatment known to enhance biological transformation over a 92-week period. Only minor amounts of radioactivity (1.0% of the bound radioactivity) were released from treated soil incubated in the presence of the lignin-degrading fungus Phanerochaete chrysosporium. Simulation of seasonal variation in temperature, including freezing of the soil, did not cause a significant release of radioactivity (1.4%). Growth and flowering of the bush bean Phaseolus vulgaris only released 0.8% of the bound radioactivity to the eluate; however, during the decomposition phase, an additional 7.7% of the bound radioactivity was released. We propose that this radioactivity was bound to soluble humic material that was mobilized due to a pH shift during the decomposition of the plant organic matter. This is supported by the observation that neither free TNT nor its metabolites were present in the eluate. During the different incubation experiments, 3.9 to 8.5% of the bound radioactivity was found as 14CO2. The results indicate a slow turnover of even strongly bound immobilized metabolites of TNT.