bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of the Spray Drift Task force database for aerial applications
Authors: Hewitt Andrew J. , Johnson David R. , Fish John D. , Hermansky Clarence G. , Valcore David L.
Published: March 2010

This article is part of a series describing the development of the Spray Drift Task Force (SDTF) database and its application to agricultural chemical exposure risk assessment modeling. The series describes the development of a large generic database (assuming that active ingredient rate is not a factor affecting physical drift) and its use in estimating spray movement immediately following application by aerial methods. The components of the database are described. In agreement with field trials in the open literature, the database shows that the major variables affecting off-target spray deposition are droplet size, spray release position (boom height and length), and wind speed and direction. In addition, secondary parameters that can affect these variables and drift are also discussed.
Kinetics of polychlorinated biphenyl dechlorination by Hudson River, New York, USA, sediment microorganisms
Authors: Cho Young-Cheol , Sokol Roger C. , Rhee G-Yull
Published: March 2010

The kinetics of polychlorinated biphenyl (PCB) dechlorination by Hudson River (New York, USA) sediment microorganisms were investigated using Aroclor 1242 at 10 concentrations ranging from 0 to 900 ppm (0–11.2 μmol Cl/g sediment). The time course of PCB dechlorination and population growth were determined by congener-specific analysis and the most-probable-number technique, respectively, over a 44-week incubation period. Dechlorination rate (nmol Cl removed/g sediment/d) was a linear function of PCB concentrations similar to the dechlorination of Aroclor 1248 by sediment microorganisms from the St. Lawrence River (New York, USA). However, the rate was much slower, with the linear slope being only 24% that of the St. Lawrence River. The threshold concentration below which no dechlorination occurs was (mean ± standard deviation) 1.06 ±0.18 μmol Cl/g sediment (85±14 ppm), threefold higher than that for the dechlorination of Aroclor 1248. The maximum extent of dechlorination was greater at higher Aroclor concentrations. Dechlorinating microorganisms did not show any significant growth until late in the lag phase of dechlorination, and their maximum was greater at higher initial Aroclor 1242 concentrations. Although dechlorination rates were significantly lower with the Hudson River inoculum, when normalized to the maximum number of dechlorinating organisms, they were not significantly different from those for Aroclor 1248 by St. Lawrence River microorganisms. These results further support the idea that PCB dechlorination is tightly linked to the growth of dechlorinating microorganisms.
Metallothionein-like metal-binding protein in the biomonitor Chaoborus: Occurrence and relationship to ambient metal concentrations in lakes
Authors: Croteau Marie-Noële , Hare Landis , Campbell Peter G. C. , Couillard Yves
Published: March 2010

Larvae of the insect Chaoborus are used to monitor cadmium (Cd) in lakes. We set out to determine if this animal possesses a metallothionein-like protein to which its Cd could be bound and if the concentrations of such a protein are correlated with those of Cd in the insect and in lakewater. To achieve our goals, we collected water and larvae of several Chaoborus species from 10 lakes situated along an environmental Cd gradient. We found that all of the Chaoborus species possess a metallothionein-like protein and that concentrations of the protein and of Cd differed among species. Concentrations of the metallothionein-like protein were directly related to those in Chaoborus and in lakewater. These direct relationships support the use of Chaoborus larvae as a Cd biomonitor.
Effects of contact time on the sequestration and bioavailability of different classes of hydrophobic organic chemicals to benthic oligochaetes (Tubificidae)
Authors: Kraaij Rik H. , Tolls Johannes , Sijm Dick , Cornelissen Gerard , Heikens Alex , Belfroid Angelique
Published: March 2010

Differences in bioavailability of hydrophobic organic compounds (HOC) to benthic deposit feeders have been related to differences in sediment-HOC contact time and sequestration (formation of slowly desorbing fractions) status. As a consequence, it was postulated that contact time and/or sequestration should be incorporated into risk assessment. In the present study, we investigated the effect of contact time on the bioavailability and sequestration of different classes of HOC. For this purpose, we simultaneously measured the steady-state accumulation into benthic oligochaetes (Tubificidae) and the distribution over rapidly and slowly desorbing fractions in laboratory-contaminated sediment at different contact times. The decrease in rapidly desorbing fractions (Frap) of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and 2,2-bis (4-chlorophenyl)-1,1-dichloroe-thylene (p,p′-DDE) after a contact time of 959 d did not exceed a factor of 1.2. Similarly, the reduction in bioavailability was a factor of 2.3 at maximum, indicating that long contact times do not necessarily result in pronounced bioavailability reduction. For chlorobenzenes, the bioavailability was reduced with a factor of 5 to 18. This decrease corresponded with a pronounced reduction in Frap, which was attributed to losses of rapidly desorbing compounds. Over 75% of the variation in biota-to-sediment accumulation factors (BSAFs) of the PAHs and chlorobenzenes at the three contact times could be explained by differences in Frap. The present study provides evidence of a relationship between sequestration status and bioavailability of HOC to benthic deposit feeders.
Changes in the potential quantum yield of photosystem II and the integrity of cell membranes relative to the elemental content of the epilithic desert lichen Ramalina maciformis
Authors: Garty Jacob , Tamir Orly , Cohen Yehudith , Lehr Haya , Goren Ayana I.
Published: March 2010

The present study used the epilithic fruticose lichen Ramalina maciformis to investigate the occurrence of mineral elements, including heavy metals, at a distance of up to 50 km from the industrial region in Ramat Hovav in the Negev Desert, Israel. The major objective of this study was an analytical comparison of elemental content and physiological parameters of lichen vitality, apart from a test of the applicability of this specific lichen in investigations of air pollution. The Ca, Cr, Cu, K, Mg, Na, Pb, S, Sr, and Zn content of thalli from the unpolluted Tellalim site collected in August 1997, transferred to 24 biomonitoring sites, and retrieved in April 1998 was analyzed in comparison with the following parameters: The potential quantum yield of photosystem II (PSII), and the integrity of cell membranes. Transplanted thalli in several sites at Ramat Hovav accumulated large amounts of most of the elements. The K content of the transplants located in the polluted sites indicated a leakage of this element, because this content was lower than that of thalli in unpolluted sites. Calcium, Cu, Mn, and Na showed an inverse correlation with the K content of the lichen. Calcium, Cu, and Sr showed an inverse correlation with the Fv/Fm ratio expressing the potential quantum yield of PSII. Calcium, Cr, Cu, Mg, Na, S, and Sr showed a positive correlation with the electrical conductivity corresponding with cell-membrane disintegration. The present study demonstrated a meaningful connection between enlarged concentrations of certain elements and physiological phenomena. The capability of the lichen to detect air pollution was found to be satisfactory. The dispersion of airborne heavy metals was found, however, to be local and limited to a few hundred meters from the source of pollution.
Evaluating the ecological significance of laboratory response data to predict population-level effects for the estruarine amphipod Ampelisca abdita
Authors: Kuhn Anne , Munns Wayne R. , Serbst Jonathan , Edwards Phillip , Cantwell Mark G. , Gleason Timothy , Pelletier Marguerite C. , Berry Walter
Published: March 2010

Ten-day acute mortality of the benthic amphipod Ampelisca abdita is used in a number of regulatory, research, and monitoring programs to evaluate chemical contamination of marine sediments. Although this endpoint has proven to be valuable for characterizing the relative toxicities of sediments, the significance of acute mortality with respect to population viability has not yet been established. In this study, population modeling along with empirical extrapolation were used to describe a relationship between acute mortality and population-level response of A. abdita. The research involved the performance of a standard 10-d sediment toxicity bioassay and a 70-d full life-cycle chronic population (including reproduction) bioassay exposing A. abdita to sediments spiked with concentrations of the divalent metal cadmium (normalized to acid volatile sulfide) expected to produce a range of biological effects. These data provided age-specific schedules of survival and fecundity that were used to parameterize an age-classified projection matrix model for A. abdita. Measured exposure data and population growth rate estimates, obtained using the demographic information collected during the 70-d assay, were used to develop exposure—response models. These data were also used to develop an empirical relationship between population growth rate (λ) and acute mortality. This relationship describes how acute data may be used to predict concentrations that produce population-level effects. Model manipulations permit extrapolation of early life-stage mortality (the acute endpoint) to changes in population growth rate. These relationships were used to evaluate a range of ecologically acceptable acute mortality for A. abdita.
Effects of chronic dietary exposure to trace elements on banded water snakes (Nerodia fasciata)
Authors: Hopkins William A. , Roe John H. , Snodgrass Joel W. , Staub Brandon P. , Jackson Brian P. , Congdon Justin D.
Published: March 2010

Little currently is known about the accumulation or effects of contaminants on reptiles. To date, most studies examining reptile exposure to trace elements report tissue burdens of field-captured animals, but seldom provide insight into the dose, duration, or mode of exposure involved. For two years, we fed juvenile banded water snakes (Nerodia fasciata) prey items collected from a coal ash—contaminated site that contained elevated levels of As, Cd, Cu, Se, Sr, and V. With the exception of Cu, snakes accumulated significant concentrations of elements, usually in a dose-dependent manner. Accumulation varied significantly among liver, kidney, and gonads, and in most cases between sexes. Selenium accumulation was most notable, greatly exceeding established toxicity thresholds for other vertebrates. Despite the high concentrations of pollutants accumulated, snakes exposed to the contaminated diet survived through the study and exhibited normal food consumption, growth, condition factor, overwinter survival and mass loss, metabolic rate, and gonadosomatic index. The results of this study confirm that diet can be a significant route of exposure to trace elements in snakes and indicate that further studies on snakes are warranted to better understand their responses to contaminants.
Sexually dimorphic morphology of hatchling snapping turtles (Chelydra serpentina) from contaminated and reference sites in the Great Lakes and St. Lawrence River basin, North America
Authors: de Solla Shane R. , Bishop Christine A. , Brooks Ronald J.
Published: March 2010

Some organochlorine pesticides and industrial chemicals may alter sexually dimorphic traits through endocrine disruption. Therefore, we examined a sexually dimorphic trait, precloacal length, of hatchling snapping turtles (Chelydra serpentina) incubated from 31 clutches from a heavily contaminated site (Hamilton Harbour, ON, Canada; n = 14), a moderately contaminated site (Akwesasne Mohawk Territory; n = 3), and from a reference site (Algonquin Provincial Park, ON, Canada; n = 14). The mean sum polychlorinated biphenyls from Algonquin were low (20.33 ng/g wet wt), but were high from both Hamilton and Akwesasne (2,956.28 and 3,377.0 ng/g wet wt, respectively). Organochlorine pesticides, such as dichlorodiphenyldichloroethylene, were low from Algonquin (1.67 ng/g wet wt), moderate from Akwesasne (10.00 ng/g wet wt), and relatively high from Hamilton (135.14 ng/g wet wt). At all sites, the precloacal length of male hatchlings was larger than that of females by an equal amount at any given body size. However, the precloacal length of both males and females from Hamilton increased with body size at a slower rate than of males and females from the other two sites. Our results support an earlier study that found differences in sexually dimorphic morphology of adult snapping turtles among contaminated and uncontaminated sites. Furthermore, these alterations in secondary sexual characteristics previously observed in adults likely are initiated early in development, and may result in permanent organizational changes in morphology.
A dynamic level IV multimedia environmental model: Application to the fate of polychlorinated biphenyls in the United Kingdom over a 60-year period
Authors: Sweetman Andrew J. , Cousins Ian T. , Seth Rajesh , Jones Kevin C. , Mackay Donald
Published: March 2010

A dynamic or level IV multimedia model is described and illustrated by application to the fate of three polychlorinated biphenyl (PCB) congeners in the United Kingdom over a 60-year period from their introduction into commerce until the present. Models of this type are shown to be valuable for elucidating the time response of environmental systems to increasing, decreasing, or pulse inputs. The suggestion is made that in addition to the outputs of time-dependent concentrations (which can be compared with monitoring data for validation purposes), it is useful to examine masses, fugacities, and fugacity ratios between media. The relative importance of processes is best evaluated by compiling cumulative intermedia fluxes and quantities lost by reaction and advection and examining the corresponding process rate constants or their reciprocals, the characteristic times. The suggestion is made that uncertainty and sensitivity analyses are desirable, but it must be appreciated that relative sensitivities of input parameters may change during the simulation period, so a single sensitivity analysis conducted at one point in time can be misleading. The use of the model for forecasting future trends in concentration is illustrated. Given the uncertainties in emission and advective inflow rates, the simulation of PCB fate in the United Kingdom is regarded as showing time trends that are in satisfactory agreement with monitoring data.
Selecting internally consistent physicochemical properties of organic compounds
Authors: Beyer Andreas , Wania Frank , Gouin Todd , Mackay Donald , Matthies Michael
Published: March 2010

Methods are presented for selecting values of chemical properties of vapor pressure, water solubility, Henry's law constant, and octanol—water and octanol—air partition coefficients, which are subject to thermodynamic constraints, while taking advantage of all measurements. The aim of the mathematical procedures is to find the one set of internally consistent partitioning parameters that is minimally divergent from the experimental values. Information about the reliability or uncertainty of reported values can be accounted for by weighing factors. A similar approach is applied to the temperature dependence of these properties. The influence of partial miscibility of the octanol—water system is discussed and a correction is suggested for this effect. The selection method is applied to 50 mostly aromatic chemicals for which multiple measured partitioning data are available. The resulting sets of consistent property data are presented and discussed.
Changes in estrogenic and androgenic activities at different stages of treatment in wastewater treatment works
Authors: Kirk Lucy A. , Tyler Charles R. , Lye Christina M. , Sumpter John P.
Published: March 2010

Estrogenic and androgenic activities of wastewater were determined during treatment in five wastewater treatment works (WWTWs) in the Untied Kingdom. With one exception, both estrogenic and androgenic activities decreased markedly as wastewater progressed through the plants; removal rates were generally 70% or higher, sometimes reaching 100%. Most of the reduction in activity occurred during secondary (biological) treatment. In both influents and effluents, estrogenic and androgenic activities were appreciably lower in samples collected in August, when the amount of rain had been substantial, compared with samples collected in April and May. Most final effluents contained very low (or nondetectable) estrogenic activity (undetectable to 13 ng/L of estradiol equivalents) and androgenic activity (undetectable to 143 ng/L of dihydrotestosterone [DHT] equivalents), although one (from a WWTW that had only primary treatment) contained relatively high activities (40 ng/L of estradiol equivalents; 4,033 ng/L of DHT equivalents). The type of treatment available at the various WWTWs also affected the activity of the final effluent. The biological significance of these results will depend upon which chemicals contribute to the estrogenic and androgenic activities, because of widely different potencies of different estrogenic chemicals, and on the degree of dilution of the effluents in their receiving waters.
Oxidation chemistry of acid-volatile sulfide during analysis
Authors: Gonzalez Adrian M.
Published: March 2010

The susceptibility of some components of sediment acid-volatile sulfide (AVS) to chemical oxidation is a critical factor impacting accurate measurement of AVS in sediment samples. This well-documented susceptibility to oxidation led to the requirement for oxygen-free conditions in the analytical method developed for AVS. In light of this acute potential to oxidize, the serendipitous finding that air can be used in the analysis of sediment AVS is counterintuitive and unexpected. To demonstrate and investigate this interesting observation, extraction experiments were performed using aqueous and solid-phase sulfide species. Experiments using air as the carrier gas showed a mean percentage recovery of sulfide matching that of traditional (nitrogen gas) analysis (i.e., >91%) and a time to completion of less than 30 min for aqueous sulfide and less than 60 min for sediment samples. These results are consistent with those of sulfide oxidation studies reported in the literature. Using air as the analytical carrier gas can provide an interesting alternative for developing an analytical method to determine AVS parameters in the field.
Using measured octanol-air partition coefficients to explain environmental partitioning of organochlorine pesticides
Authors: Shoeib Mahiba , Harner Tom
Published: March 2010

Octanol-air partition coefficients (Koa) were measured directly for 19 organochlorine (OC) pesticides over the temperature range of 5 to 35°C. Values of log Koa at 25°C ranged over three orders of magnitude, from 7.4 for hexachlorobenzene to 10.1 for 1,1-dichloro-2,2-bis (p-chlorophenyl) ethane. Measured values were compared to values calculated as KowRT/H (where R is the ideal gas constant [8.314 J mol−1 K−1], T is absolute temperature, and H is Henry's law constant) were, in general, larger. Discrepancies of up to three orders of magnitude were observed, highlighting the need for direct measurements of Koa. Plots of Koa versus inverse absolute temperature exhibited a log-linear correlation. Enthalpies of phase transition between octanol and air (ΔHoa) were determined from the temperature slopes and were in the range of 56 to 105 kJ mol−1 K−1. Activity coefficients in octanol (γo) were determined from Koa and reported supercooled liquid vapor pressures (p oL), and these were in the range of 0.3 to 12, indicating near-ideal solution behavior. Differences in Koa values for structural isomers of hexachlorocyclohexane were also explored. A Koa-based model was described for predicting the partitioning of OC pesticides to aerosols and used to calculate particulate fractions at 25 and −10°C. The model also agreed well with experimental results for several OC pesticides that were equilibrated with urban aerosols in the laboratory. A log-log regression of the particle-gas partition coefficient versus Koa had a slope near unity, indicating that octanol is a good surrogate for the aerosol organic matter.
Identification of polychlorinated dibenzo-p-dioxin, dibenzofuran, and coplanar polychlorinated biphenyl sources in Tokyo Bay, Japan
Authors: Yao Yuan , Masunaga Shigeki , Takada Hideshige , Nakanishi Junko
Published: March 2010

A dated sediment core collected from Tokyo Bay, Japan, was used to assess the historical inputs of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) from multiple sources. The levels, patterns, and profiles of these compounds in the core were congener-specifically investigated, and the results show that the PCDD and PCDF (PCDD/F) and the Co-PCB inputs increased abruptly from the late 1950s and peaked during the period 1967 to 1972. From 1972 to 1981, the inputs decreased continuously and then generally leveled off. Using principal component analysis, two herbicides widely used in the past, pentachlorophenol (PCP) and chloronitrofen (CNP), as well as combustion processes were identified as the major dioxin sources in Tokyo Bay. The PCB formulations and combustion processes were estimated to be the major sources of Co-PCBs. Furthermore, multiple regression analysis was performed for dioxin-source apportioning, and it was found that the herbicides PCP and CNP have mainly contributed to the PCDD/F burdens since the late 1950s. This study suggests that herbicide-derived PCDD/Fs remaining in agricultural land will continue to run off and pollute the aquatic environment in Japan for a long time.
Precautions in the use of 110mAg as a tracer of silver metabolism in ecotoxicology: Preferential bioconcentration of 109Cd by trout gills after 110mAg exposure
Authors: Hansen Heinz J. M. , Grosell Martin , Jacobsen Ulf , Jørgensen Jesper C. , Hogstrand Christer , Wood Christopher M.
Published: March 2010

An often overlooked problem in the use of radiotracers is the possibility of isotopic contamination. Commercially available silver 110mAg was used to study silver uptake and depuration in rainbow trout and European eel. Quality control by means of comparative γ and β counting brought our attention to a contamination of the 110mAg stock with 109Cd, which could be seen only because the 109Cd was markedly bioconcentrated by trout gills. The contamination could not be detected in eel gills or in other tissues of both species. The difference between trout and eel gill structure and function is the probable explanation for the marked difference in 109Cd accumulation. This contamination was identified as 109Cd by γ spectroscopy and its origin by transmutation of natural silver as a result of neutron activation is described. Failure to recognize this contamination problem would have resulted in serious misinterpretation of the data set. Guidance for avoiding this problem is given.
Immunochemical quantification of metallothioneins in marine mollusks: Characterization of a metal exposure bioindicator
Authors: Boutet Isabelle , Tanguy Arnaud , Auffret Michel , Riso Ricardo , Moraga Dario
Published: March 2010

A recombinant metallothionein CgMT1, from the Pacific oyster Crassostrea gigas, was synthesized and used as antigen in the development of antibodies and a specific enzyme-linked immunosorbent assay (ELISA). The ELISA showed that rabbit anti-CgMT1 IgG reacted with purified CgMT1 and MTs from other marine bivalves, indicating its suitability as a reagent to quantify MTs and for monitoring of metal contamination in field animals. Application of this assay to tissues excised from metal exposed C. gigas showed that MT induction reached a saturation level in gills that was not observed in digestive gland. Quantification of MTs in gills and digestive gland of field-collected C. gigas showed that the MT level depended on the metal concentrations at the collection sites and may have been influenced by salinity variations at estuarine sites. Oysters from metal-contaminated estuarine sites showed lower MT concentrations than those from nonestuarine contaminated sites.
Lysosomal response of earthworm (Eisenia fetida) coelomocytes to the fungicide copper oxychloride and relation to life-cycle parameters
Authors: Reinecke Sophiè A. , Helling Beate , Reinecke Adriaan J.
Published: March 2010

Juvenile specimens of the earthworm species Eisenia fetida Savigny, 1826, were exposed in the laboratory to a range of concentrations of the fungicide copper oxychloride. After an eight-week exposure period, the neutral-red retention (NRR) times were measured in the coelomocytes of all the worms that had matured. Life-cycle traits (survival, biomass change, cocoon production, cocoon mass, hatching of cocoons, number of hatchlings) were also monitored. Dose-related effects on NRR times, maturation, growth, and reproduction parameters were determined (one-way analysis of variance, p < 0.05). The lowest effect concentration for substrate copper (Cu) measured for the NRR time was 8.9 mg/kg (dry wt). Growth was severely affected at the highest exposure concentration (330 mg/kg substrate dry wt), at which no worms matured and no NRR times could be measured. Negative linear correlations (p < 0.05) were apparent between the NRR times and substrate and body Cu concentrations. Positive linear relationships were found between the NRR times and some life-cycle parameters (p < 0.05). This study showed that the NRR assay can indicate toxic stress due to Cu exposure at an early stage, and that NRR times can be linked to effects on certain life-cycle traits.
Evaluating best management practices at an urban golf course
Authors: Davis Nate M. , Lydy Michael J.
Published: March 2010

This three-year study evaluated the effects of best management practices (BMPs) in reducing surface water contamination at an urban golf course. Water samples were collected before BMP implementation from two ponds on Braeburn Golf Course (Wichita, KS, USA). The pesticides 2,4-dicholorodiphenoxyacetic acid (2,4-D) and simazine were periodically found at concentrations above recommended water quality criteria. Excessive nutrients in the form of nitrates and total phosphorus were also measured. In addition, an assessment of macroinvertebrate populations revealed only a few tolerant species. Beginning in year 2, recommendations to alter chemical applications on the course were implemented as part of the BMPs. Surface water sampling during year 2 showed significant declines in nitrate and total phosphorus levels; however, seasonal contamination from pesticides continued to occur. Beginning in year 3, structural changes to the golf course were made as part of the BMPs. Subsequent water sampling indicated further reductions of nitrates (80%) and total phosphorus (40 and 60% in the two ponds, respectively), and elimination of contamination from spring applications of 2,4-D and simazine. Finally, an assessment of macroinvertebrate populations indicated an improvement in taxa richness, as well as repopulation by less tolerant organisms. Results of this study can be used to develop and refine golf course management procedures to protect aquatic environments.
The agricultural dispersal-valley drift spray drift modeling system compared with pesticide drift data
Authors: Allwine K. Jerry , Thistle Harold W. , Teske Milton E. , Anhold John
Published: March 2010

The coupling of the valley drift (VALDRIFT) atmospheric dispersion/deposition model with the agricultural dispersal (AGDISP) aircraft wake model generates a modeling system for predicting the off-target drift of pesticides sprayed in a mountain valley. The approach uses the AGDISP near-field spray model to estimate the mass fraction of pesticide remaining airborne after initial application, then the VALDRIFT complex terrain model to estimate the drift of pesticide from the target area. The modeling system inputs include detailed spray information, a measure (or estimate) of winds in the valley, and the valley topographic characteristics; the results are pesticide concentrations throughout the valley atmosphere and pesticide deposition to the valley surface. The AGDISP and VALDRIFT models are operated independently, with the results from AGDISP being used as input to VALDRIFT through user-created data files. The modeling system was evaluated using pesticide drift data from spray trials conducted in the Mill Creek Canyon of Utah's Wasatch Mountains, USA, during the late spring of 1993. The predicted deposition compared within a factor of three of the observations (70% of the time) at all sampling locations extending several kilometers down-valley from the spray treatment block. The overall average ratio of predicted-to-observed deposition was 0.9.
Use of physical, chemical, and biological indices to assess impacts of contaminants and physical habitat alteration in urban streams
Authors: Rogers Catriona E. , Brabander Daniel J. , Barbour Michael T. , Hemond Harold F.
Published: March 2010

Human activities in urban areas can lead to both chemical pollution and physical alteration of stream habitats. The evaluation of ecological impacts on urban streams can be problematic where both types of degradation occur. Effects of contaminants, for example, may be masked if stream channelization, loss of riparian vegetation, or other physical stressors exert comparable or larger influences. In the Aberjona watershed (near Boston, MA, USA), we used physical, chemical, and biological indices to discern the relative impacts of physical and chemical stressors. We used standard protocols for assessing the biological condition of low-gradient streams, sampling macroinvertebrate communities from several different habitat types (e.g., overhanging bank vegetation, undercut bank roots, and vegetation on rocks). We strengthened the linkage between chemical exposure and macroinvertebrate response by measuring metal concentrations not only in sediments from the stream bottom but also in the vegetative habitats where the macroinvertebrates were sampled. Linear regression analysis indicated that biological condition was significantly dependent (95% confidence level) on contaminants in vegetative habitats, but not on contaminants in sediments from the stream bottom. Biological condition was also significantly dependent on physical habitat quality; regression analysis on both contaminants and physical quality yielded the best regression model (r2 = 0.49). Similar biological impairment was observed at sites with severe contamination or physical impairment or with moderate chemical and physical impairment. These results have implications for the management of urban streams.
Predicting levels of stress from biological assessment data: Empirical models from the Eastern Corn Belt Plains, Ohio, Usa
Authors: Norton Susan B. , Cormier Susan M. , Smith Marc , Jones R. Christian , Schubauer-Berigan Mary
Published: March 2010

Interest is increasing in using biological community data to provide information on the specific types of anthropogenic influences impacting streams. We built empirical models that predict the level of six different types of stress with fish and benthic macroinvertebrate data as explanatory variables. Significant models were found for six stressor factors: stream corridor structure; siltation; total suspended solids (TSS), biochemical oxygen demand (BOD), and iron (Fe); chemical oxygen demand (COD) and BOD; zinc (Zn) and lead (Pb); and nitrate and nitrite (NOx) and phosphorus (P). Model R2 values were lowest for the siltation factor and highest for TSS, BOD, and Fe. Model R2 values increased when spatial relationships were incorporated into the model. The models generally performed well when applied to a random subset of the data. Performance was more mixed when models were applied to data collected from a previous time period, perhaps because of a change in the spatial structure of these systems. These models may provide a useful indication of the levels of different stresses impacting stream reaches in the Eastern Corn Belt Plains ecoregion of Ohio, USA. More generally, the models provide additional evidence that biological communities can serve as useful indicators of the types of anthropogenic stress impacting aquatic systems.
Fate and bioaccumulation of isoproturon in outdoor aquatic microcosms
Authors: Merlin Gerard , Vuillod Maryline , Lissolo Thierry , Clement Bernard
Published: March 2010

To gain information concerning the ecotoxicity of isoproturon (IPU) on aquatic ecosystems, six experimental ponds of 5 m3 each were studied. All the experiments were conducted during the summer over two years. Three different types of ecosystems were tested in 1994 and one type of ecosystem was selected and repeated in 1995 with three replicates. In each case, the initial concentration of IPU contamination was set at 10 μg/L. The IPU concentration was determined in the water column and in different species (mainly plants) of the microcosms. A first-order kinetic decrease in IPU concentration was observed in 1994, with half-life ranging from 15 to 35 d, depending on the microcosms. This relatively fast decrease was also confirmed in 1995, but it reached a constant value after two months. A high variability of the IPU concentration was observed in exposed plants, with bioconcentration factors ranging from 100 to 1,200 with large coefficients of variation. The observed plant bioconcentration factors are higher than those predicted by usual numerical models, probably due to the specific binding of IPU on one protein of the photosynthetic apparatus. Our data show that bioconcentration does not occur in mollusks but is important in photosynthetic organisms. Plant bioconcentration and microbial biodegradation are the main processes involved in the IPU decay in our outdoor aquatic microcosms.
Social interactions affect physiological consequences of sublethal copper exposure in rainbow trout, Oncorhynchus mykiss
Authors: Sloman Katherine A. , Baker Daniel W. , Wood Chris M. , McDonald Gordon
Published: March 2010

The interactions of sublethal waterborne copper exposure and social dominance behavior were examined in juvenile rainbow trout. Dominance hierarchies were determined between pairs of fish by behavioral observations and among groups of 10 fish by the use of passive integrated transponder (PIT) tagging equipment. The present study is one of the first to utilize this novel PIT tag method for behavioral assessment. Feeding behavior was quantified by placing a PIT tag recorder at the entrance to the feeding area. Linear dominance hierarchies were documented based on these observations of feeding behavior. Dominance hierarchies established in control water were not altered by exposure to 30 μg/L of copper; however, physiological responses of fish to sublethal concentrations of copper were related to social rank. Subordinate fish exhibited a higher accumulation of copper in both gill and liver tissue. Subordinates of paired fish were also shown to have a higher uptake of sodium than dominant fish, and the uptake of sodium was correlated with uptake of copper from the water. Therefore, within a population of fish, it cannot be assumed that individuals of different social status will exhibit the same physiological responses to the presence of copper.
Response of the amphibian tadpole Xenopus laevis to atrazine during sexual differentiation of the ovary
Authors: Tavera-Mendoza Luz , Ruby Sylvia , Brousseau Pauline , Fournier Michel , Cyr Daniel , Marcogliese David
Published: March 2010

Xenopus laevis tadpoles (stage 56) were exposed to 21 μg/L atrazine under laboratory-controlled conditions in a static system. Following a 48-h exposure period at 21 ± 0.5°C during sexual differentiation, tadpoles were fixed, and the kidney-gonad complex was microdissected. Quantitative histological analysis revealed in a trazine-exposed ovaries a significant (p < 0.05) increase in frequency of secondary oogonia. Atresia, or oogonial resorption of both primary and secondary oogonia, also increased significantly (p < 0.05). The results suggest that these primary germ cells, which constitute the total number of germ cells in the ovary for the reproductive life of the organism, were reduced by 20% following a 48-h exposure period compared to 2% in controls.
Bauxite manufacturing residues from Gardanne (France) and Portovesme (Italy) exert different patterns of pollution and toxicity to sea urchin embryos
Authors: Pagano Giovanni , de Biase Antonella , Iaccarino Mario , Meric Sureyya , Petruzzelli Domenico , Tünay Olcay , Warnau Michel , Trieff Norman M.
Published: March 2010

This study was designed to investigate the composition and toxicity of solid residues from bauxite manufacturing plants. Soil and dust samples were collected in the proximity of two bauxite plants (Gardanne, France, and Portovesme, Italy). Samples were analyzed for their content of some selected inorganic contaminants by means of inductively coupled plasma optical emission spectroscopy (ICP-OES) either following acid digestion procedures or by seawater release of soluble components. Toxicity was tested by sea urchin bioassays to evaluate a set of toxicity endpoints including acute embryotoxicity, developmental defects, changes in sperm fertilization success, transmissible damage from sperm to the offspring, and cytogenetic abnormalities. Inorganic analysis showed two distinct sets of inorganic contaminants in Gardanne versus Portovesme, including Al, Cr, Cu, Fe, Mn, Pb, Ti, and Zn; sample composition (seawater-soluble cotaminants) and toxicity showed a noteworthy association. The most severe toxicity to embryogenesis and to sperm fertilization success was exerted by some Portovesme samples (0.03–0.5% w/v), with a significant association between toxicity and dose-related seawater release of Zn, Pb, and Mn. Seawater extraction of a toxic dust sample (G20) from the Gardanne factory showed increasing seawater release of Al, Fe, and Mn; the G20 sample, at the level of 0.5%, affected both developing sea urchin embryos and sperm (offspring quality). Soil samples around the Gardanne factory showed the highest frequency of toxic soil sites eastward from the factory. The present data point to solid deposition from bauxite plants as a potential subject of environmental health concern. The results suggest that extraction methods for evaluating the toxicity of complex mixtures should be based on the environmental availability of mixture components. The differences in sample toxicity among the tested sites, however, suggest possible site-to-site variability in geochemical and/or technological parameters.
Evaluation of the effect of reactive sulfide on the acute toxicity of silver (I) to Daphnia magna. Part 1: Description of the chemical system
Authors: Bowles Karl C. , Bianchini Adalto , Brauner Colin J. , Kramer James R. , Wood Chris M.
Published: March 2010

Experiments were designed to assess the potential protective effect of the presence of sulfide against the acute (48-h) toxicity of silver(I) to Daphnia magna. Tests were conducted in borosilicate glass beakers (250 ml) in moderately hard synthetic water. Toxicity solutions were replaced after 24 h by static renewal method. This paper describes the chemical system, and the acute toxicity results are presented in a companion paper. Sulfide was below detection limit (<5 nM) in controls with no sulfide added. Sulfide, added as zinc sulfide clusters at approximately 35- or approximately 350-nM concentration, dropped in concentration to approximately 25 and 250 nM, respectively, over the 24-h period of measurements. Silver also decreased in concentration during the experiment (up to 59%), and the rate of loss was greater in the absence of sulfide compared with the presence of sulfide. A filtration experiment indicated a 1:1 binding ratio of silver to sulfide and a conditional stability constant for the Ag(I)-zinc sulfide complex of log K' = 8.9. The losses of sulfide and silver during the experiments highlighted the need for regular monitoring of the important chemical components of the system, even during short (48-h) toxicity tests.
Aquatic toxicity of triclosan
Authors: Orvos David R. , Versteeg Donald J. , Inauen Josef , Capdevielle Marie , Rothenstein Arthur , Cunningham Virginia
Published: March 2010

The aquatic toxicity of triclosan (TCS), a chlorinated biphenyl ether used as an antimicrobial in consumer products, was studied with activated-sludge microorganisms, algae, invertebrates, and fish. Triclosan, a compound used for inhibiting microbial growth, was not toxic to wastewater microorganisms at concentrations less than aqueous solubility. The 48-h Daphnia magna median effective concentration (EC50) was 390 μg/L and the 96-h median lethal concentration values for Pimephales promelas and Lepomis macrochirus were 260 and 370 μg/L, respectively. A no-observed-effect concentration (NOEC) and lowest-observed-effect concentration of 34.1 μg/L and 71.3 μg/L, respectively, were determined with an early life-stage toxicity test with Onco-rhynchus mykiss. During a 96-h Scenedesmus study, the 96-h biomass EC50 was 1.4 μg/L and the 96-h NOEC was 0.69 μg/L. Other algae and Lemna also were investigated. Bioconcentration was assessed with Danio rerio. The average TCS accumulation factor over the five-week test period was 4,157 at 3 μg/L and 2,532 at 30 μg/L. Algae were determined to be the most susceptible organisms. Toxicity of a TCS-containing wastewater secondary effluent to P. promelas and Ceriodaphnia was evaluated and no observed differences in toxicity between control and TCS-treated laboratory units were detected. The neutral form of TCS was determined to be associated with toxic effects. Ionization and sorption will mitigate those effects in the aquatic compartment.
Dynamic equilibrium dissolution of complex nonaqueous phase liquid mixtures into the aqueous phase
Authors: Schluep Mathias , Gälli René , Imboden Dieter M. , Zeyer Josef
Published: March 2010

Human health risks posed by hazardous substances seeping from a pool of nonaqueous phase liquids (NAPLs) into groundwater change over time because the more soluble compounds such as benzene, toluene, ethylbenzene, and xylene (BTEX) dissolve faster into the aqueous phase than less soluble compounds such as polycyclic aromatic hydrocarbons (PAH). Long-term dissolution from diesel fuel into the aqueous phase was determined experimentally in a continuous flow-through system using the slow-stirring method. The data obtained are interpreted using a dynamic equilibrium dissolution model based on Raoult's law. The predicted temporal development of aqueous concentrations are in good agreement with the experimental results. When a compound in the NAPL approaches complete depletion, a tailing behavior is observed, which is assigned to nonequilibrium effects, such as mass transfer limitations in the NAPL phase. The model predicted an increase of the mean molar mass of the diesel fuel of 1.5% over the entire experimental period. It should be noted that, if the dissolution process were to proceed further, the change in the mean molar mass could become significant and render the simple model inaccurate. Yet the simple model supports the assessment of initial action after a contamination event as well as the planning of long-term remedial strategies.
Isolation of compounds from bleached kraft mill recovery condensates associated with reduced levels of testosterone in mummichog (Fundulus heteroclitus)
Authors: Hewitt L. Mark , Smyth Shirley Anne M. , Dubé Monique G. , Gilman Christine I. , MacLatchy Deborah L.
Published: March 2010

Previouss studies have identified chemical recovery condensates as a primary source of hormonally active substances within a Canadian bleached kraft pulp mill. Although reverse osmosis treatment of condensates raises the exposure threshold that alters circulating levels of testosterone in mummichog (Fundulus heteroclitus), the responsible chemicals have not been characterized. In this study, a solid-phase extraction (SPE) method was developed to isolate chemical recovery condensate extractives for evaluation of hormonal activity. Condensates generated during softwood and hardwood pulp production were investigated for their relative potential to affect both circulating and gonadal production of sex steroids in mummichog. Mummichog were exposed to whole condensates, extracts from suspended particulates (>1 μm), two fractions from SPE, and residual condensates after SPE. The distribution of bioactivity among condensate fractions was similar for both wood furnishes. In both sexes, significant depressions in circulating testosterone and in in vitro gonadal testosterone production were associated with exposure to whole condensates, particulate extracts, one SPE fraction, and residual material after SPE. An optimized SPE method subsequently demonstrated complete recovery of polar, bioavailable chemicals that reduced testosterone levels in both sexes. Characterizations of active fractions by gas chromatography-mass spectrometry (GC-MS) showed the presence of extractives with molecular masses ⩾240 amu possessing functionalities consistent with lignin degradation products. This study provides the first isolation of chemicals derived from pulp production associated with impaired reproductive performance in fish.
Effect of adsorption to elemental iron on the transformation of 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine in solution
Authors: Oh Seok-Young , Cha Daniel K. , Kim Byung J. , Chiu Pei C.
Published: March 2010

The effect of adsorption to elemental iron on the reductive transformation of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (royal demolition explosive [RDX]) in aqueous solution was studied with scrap iron and high-purity iron. In batch experiments with the same total iron surface area and a mixing rate of 100 rpm, TNT and RDX were removed from the solution within 30 min. With high-purity iron, adsorbed TNT was reduced to 2,4,6-triaminotoluene (TAT) rapidly, with little accumulation of intermediates at the surface. With scrap iron, the extent of adsorption of TNT and its daughter products was more significant and reduction of these adsorbed molecules to TAT was slower. Distribution of the intermediates indicated that the reaction with scrap iron occurred primarily through reduction of the ortho nitro group. Kinetic analysis suggests that mass transfer or adsorption of TNT controlled the overall rate of TNT reduction to TAT with pure iron, whereas with scrap iron, the rate of TAT formation was probably limited by other processes. Compared to TNT, transformation of adsorbed RDX was more rapid and less affected by iron type. The RDX was reduced to an unidentified, water-soluble intermediate and NH+4, which accounted for approximately 50% of the RDX nitrogen. No total organic carbon reduction was observed before and after RDX transformation with scrap iron.