bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the luciferase recombinant cell culture bioassay system for the analysis of polycyclic aromatic hydrocarbons
Authors: Ziccardi Michael H. , Gardner Ian A. , Denison Michael S.
Published: March 2010

An aryl hydrocarbon (Ah) receptor-based luciferase cell culture bioassay developed to detect 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other halogenated aromatics was modified and optimized to detect and quantitate polycyclic aromatics (PAHs). Twenty-four PAHs were analyzed, and subsequent EC50 and EC20 concentrations (based on the median and 20% TCDD maximal response, respectively) and appropriate induction equivalency factors (calculated by comparison to the response obtained with TCDD) were determined from dose-response experiments. Six compounds were shown to be active in the system, with benzo[k]fluoranthene > benz[a,h]anthracene ≈ indeno[1,2,3-cd]pyrene > benzo[a]pyrene > benzo[b]fluoranthene > chrysene. A complex mixture of 16 PAHs was also analyzed using this system, and overall induction equivalency (or I-EQ) of the mixture was shown to be very similar to that predicted from the sum of the activity estimated for each individual PAH. Overall, our results strongly support the use of this system for the detection and relative quantitation of Ah receptor-active PAHs.
Products of aqueous chlorination of 4-nonylphenol and their estrogenic activity
Authors: Hu Jian-Ying , Xie Guo-Hong , Aizawa Takako
Published: March 2010

Seven reaction products (2-chloro-4-nonylphenol [NP], 2,6-dichloro-4-NP, trichlorophenol, 4-propyl-2′-hydroxyphenol, 4-isobutyl-2′-hydroxyphenol, 4-isoamyl-2′-hydroxyphenol, and 4-isopentyl-2′-hydroxyphenol) were identified by gas chromatography/mass spectrometry (GC/MS) in order to assess the estrogenic activity originated from 4-nonylphenol (4-NP) in drinking water. The estrogenic activities of the aqueous chlorinated 4-NP solution at 10, 60, and 120 min chlorination time were assessed by a yeast two-hybrid system based on the ligand-dependent interaction of two proteins, a human estrogen receptor (ER), and a coactivator. It was found that all three solutions inhibited transcriptional activation induction by 4-NP. Further experiments showed that these solutions also inhibited β-galactosidase induction by 17β-estradiol. For the solution at 10 min, the inhibition was found to be due to its toxicity, with an inhibition concentration (IC50) of about 10-fold of concentration of chlorinated 4-NP solution, suggesting the existence of some products with higher yeast toxicity than that of the parent 4-NP. Similar inhibition trends were also found in the dose response of the two solutions at 60 and 120 min, with an IC50 of 10-fold concentration. In these cases, the effects were considered to result from their antagonist action because the two solutions show lower yeast toxicity of which IC50 is 45-fold concentration. This suggests that some products in the chlorinated 4-NP solution elicit the antiestrogenic activities.
Silver concentrations in Colorado, USA, watersheds using improved methodology
Authors: Wen Liang-Saw , Santschi Peter H. , Gill Gary A. , Tang Degui
Published: March 2010

River water samples were collected at five sites in the state of Colorado, USA, to assess the impact of municipal and industrial discharges on Ag concentrations and speciation in surface waters. Samples were collected and analyzed for total (unfiltered collections), filtered (0.1 and 0.4 μm), particulate (≥0.45 μm), and colloidal Ag (3 kDa-0.1 μm) using ultraclean protocols. A series of laboratory experiments were conducted to assess bias from sample storage, digestion, and preconcentration protocols. In general, upstream unfiltered and particulate Ag concentrations fell within a fairly narrow range, 3.1 to 21 ng/L and 0.2 to 1.7 μg/g, respectively. Downstream unfiltered and particulate Ag concentrations showed a more broad range, 2.8 to 1,110 ng/L and 0.5 to 104 μLg/g, respectively, and reflected attenuated impacts of Ag-laden discharge effluents. However, Ag concentrations in the 0.1-μm filter-passing fraction 0.8 to 1.2 km downstream from major treatment plant effluents were all below the chronic silver criteria. On average, more than 60% of the 0.1-μm filter-passing Ag was associated with colloidal macromolecular organic matter. Silver concentrations in colloids (μg/g) were, on average, the same as those in suspended particulate matter. The percentage abundance of colloidal Ag was similar to that of dissolved organic carbon, suggesting that strong Ag binding ligands exist in both the colloidal and the particle size fractions, as these macromolecular ligands likely play a major role in Ag speciation.
Aerobic degradation of ethyl-tert-butyl ether by a microbial consortium: Selection and evaluation of biodegradation ability
Authors: Kharoune Mourad , Kharoune Lynda , Lebault Jean-Michael , Pauss André
Published: March 2010

A microbial consortium that degrades ethyl-tert-butyl ether (ETBE) as the sole source of carbon and energy under aerobic conditions was selected from a gasoline-polluted soil. This consortium consists of a variety of microorganisms with a predominance of filamentous morphology. Degradation of ETBE was found to be solely related to bacterial activity. After prolonged cultivation followed by successive transfers, the consortium's degradation ability was improved and reached a specific degradation rate of 95 mg/gprotein/h (about 146 mg/gdry wt/h). This exceeds the previously reported rates in the literature for ETBE-degrading microorganisms as pure or mixed cultures. Furthermore, a stoichiometric balance of chemical oxygen demand (COD) removal and oxygen uptake with ETBE removal provides indirect evidence of complete degradation. The consortium's activity was not inhibited by high ETBE concentrations (≤1,600 mg/L), and large inoculum sizes (≥120 mgprotein/L) were desirable for a faster and complete degradation of ETBE. The enriched consortium was also able to completely degrade methyl-tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and tert-butyl alcohol (TBA), both alone and in mixture with ETBE, without any measurable release of major degradation intermediates. In each case, MTBE and TAME exhibited the most significant resistance to degradation while TBA was rapidly degraded.
Effect of pH on cadmium toxicity, speciation, and accumulation during naphthalene biodegradation
Authors: Sandrin Todd R. , Maier Raina M.
Published: March 2010

Lowering pH of a microbiological medium from 7 to 4 decreased cadmium toxicity during naphthalene biodegradation by a Burkholderia sp. Cadmium speciation and cadmium accumulation in the system were studied to explain this effect. Cadmium speciation was determined by direct measurement and by geochemical modeling. Previous studies have implicated the monovalent hydroxylated cadmium (CdOH+) species in the effect of pH on cadmium toxicity. Modeling analysis predicted CdOH+ formation only at very low concentrations (≤0.0128 μM), while the measured concentration of divalent ionic cadmium (Cd2+) was at least three orders of magnitude greater, suggesting that Cd2+ is the more significant metal form. With respect to cadmium accumulation, cells contained in media adjusted to pH 4 accumulated only 2.76 ± 0.76 mg Cd/g cells, whereas cells in media adjusted to pH 7 accumulated 8.52 ± 0.71 mg Cd/g cells. These data suggest that cadmium toxicity is correlated with increased cadmium accumulation rather than the formation of CdOH+ as pH is increased. At low pH, the decrease in cadmium accumulation may be caused by increased competition between hydrogen and cadmium ions for binding sites on the cell surface or by an increase in metal efflux pump activity due to an increase in the proton gradient that drives the efflux pump.
A combined microcosm and field approach to evaluate the aquatic toxicity of azinphosmethyl to stream communities
Authors: Schulz Ralf , Thiere Geraldine , Dabrowski James M.
Published: March 2010

We evaluated the potential effects of the organophosphate insecticide azinphosmethyl (AZ) in a combined microcosm and field approach. The upper regions of the Lourens River, South Africa, are free of contamination (control site), whereas the subsequent stretches flowing through a 400-ha orchard area receive transient insecticide pollution (e.g., 0.82 μ/L AZP, 344 μg/kg chlorpyrifos) following spray drift and runoff (contaminated site). Stones taken from the control site were transferred to outdoor microcosms (1.5 × 0.2 × 0.2 m), providing 12 core species and approximately 350 individuals per microcosm. Microcosms were contaminated for 1 h with AZP (control, 0.2, 1, 5, and 20 μ/L; three replicates each), and acute effects on survival were evaluated 6 d following exposure. The two strongest treatments (measured concentrations: 19.2 ± 1.0 and 4.9 ± 0.3 μ/L, respectively) resulted in a significantly (analysis of variance) reduced invertebrate density, attributed mainly to various insect taxa, such as Demoreptus sp., Castanophlebia sp., Simuliidae, and Chironomidae. In contrast, Aeshna sp., Dugesia sp., Ceratopogonidae, and Cheumatopsyche sp. were unaffected. In parallel, we conducted a quantitative macroinvertebrate survey at the control site and the contaminated site of the Lourens River after the seasonal pesticide application period. The two sites contained a similar number of species but differed considerably in their species composition and abundances. Five of the eight species that were affected by AZP in the microcosm study occurred in the field at significantly lower densities at the contaminated than at the control site or were absent at the contaminated site. All of the four species that were unaffected in the microcosm occurred at significantly higher densities at the contaminated field site. Only 3 of the 12 species reacted differently in the microcosm and the field study. We conclude that microcosm studies employing a field-relevant design could be linked successfully to field studies and our results suggest that transient pesticide contamination affects the aquatic communities of the Lourens River.
Effects of depleted uranium on the health and survival ofCeriodaphnia dubiaandHyalella azteca
Authors: Kuhne Wendy W , Caldwell Colleen A. , Gould William R. , Fresquez Philip R. , Finger Susan
Published: March 2010

Depleted uranium (DU) has been used as a substitute for the fissionable enricheduranium component of atomic weapons tested at Los Alamos National Laboratory (LANL) (Los Alamos, NM, USA) since the early 1950s, resulting in considerable concentrations of DU in the soils within the test sites. Although the movement of DU into major aquatic systems has been shown to be minimal, there are many small-order ephemeral streams and areas of standing water in canyons throughout LANL that may be affected by inputs of DU via runoff, erosion, and leaching. Ninety-six-hour acute and 7-d chronic toxicity assays were conducted to measure the toxicity of DU on survival and reproduction of Ceriodaphnia dubia. A 14-d water-only assay was conducted to measure survival and growth of Hyalella azteca. The estimated median lethal concentration (LC50) to produce 50% mortality of the test population for the 96-h Ceriodaphnia dubia assay was 10.50 mg/L. Reproductive effects occurred at a lowest-observable-effect concentration ≥3.91 mg/L with a no-observable-effect concentration of 1.97 mg/L. The estimated 14-d LC50 for the Hyalella azteca assay was 1.52 mg/L. No significant relationship was detected between growth and DU concentrations. Concentrations at which toxicity effects were observed in this study for both invertebrates exceeded concentrations of total uranium observed in runoff from LANL lands. Thus, it is likely that current runoff levels of uranium do not pose a threat to these types of aquatic invertebrates.
Polychlorinated biphenyls and toxaphene in Pacific tree frog tadpoles (Hyla regilla) from the California Sierra Nevada, USA
Authors: Angermann Jeffrey E. , Fellers Gary M. , Matsumura Fumio
Published: March 2010

Pacific tree frog (Hyla regilla) tadpoles were collected throughout the Sierra Nevada mountain range, California, USA, in 1996 and 1997 and analyzed for the presence of polychlorinated biphenyls (PCBs) and toxaphene. Whole-tadpole Σ PCB levels ranged from 244 ng/g (wet wt) at lower elevations on the western slope to 1.6 ng/g high on the eastern slope, whereas Σ toxaphene levels ranged from 15.6 to 1.5 ng/g. Linear regression of PCB and toxaphene residue levels versus elevation indicated a significant relationship, with an r2 value of 0.33 for PCB and 0.45 for toxaphene indicating a significant elevation effect on PCB and toxaphene bioaccumulation in Sierra Nevada H. regilla. Tadpole samples from sites in east-facing versus west-facing drainage basins showed significant differences in PCB and toxaphene residue levels, suggesting the possibility of a rain-shadow effect in the long-range atmospheric transport of these contaminants to the Sierra Nevada Mountains.
Metabolites of polychlorinated biphenyls in human liver and adipose tissue
Authors: Guvenius Daiva Meironyte , Hassanzadeh Pari , Bergman Ake , Norent Koidu
Published: March 2010

A method for analysis of hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) was developed and adopted to the previously described method for determination of PCBs and methylsulfonyl-PCBs (MeSO2-PCBs) in human liver and adipose tissue. The concentrations of OH-PCBs (14 congeners), MeSO2-PCBs (24 congeners), and PCBs (17 congeners) in five paired samples of human liver and adipose tissue are reported. The sum of OH-PCB congeners was higher in liver (7–175 ng/g lipids) than in adipose tissue (0.3–9 ng/g lipids). In both liver and adipose tissue, 2,2′,3,4,4′,5′-hexachloro-3′-biphenylol (3′-OH-CB138) and 2,2′,3,3′,4,5′-hexachloro-4′-biphenylol (4′-OH-CB130) were the predominant hydroxylated PCB metabolites. The sum of OH-PCB congeners were of the same order of magnitude as those of methylsulfonyl metabolites of PCB in the same samples, 12 to 358 ng/g lipids and 2 to 9 ng/g lipids in liver and adipose tissue, respectively. The levels of PCBs were similar in liver and adipose tissue, 459 to 2,085 ng/g lipids and 561 to 2,343 ng/g lipids, respectively. The sum of OH-PCBs and the sum of MeSO2-PCBs correlated to the sum of PCBs. The determined PCB metabolites constituted 3 to 26% of total PCB concentration in the liver and 0.3 to 0.8% of total PCBs in the adipose tissue samples.
Relationships between contaminant levels in marine sediments and their biological effects on embryos of oysters,Crassostrea gigas
Authors: Geffard Olivier , Budzinski Helene , His Edouard , Seaman Matthias N. L. , Garrigues Philippe
Published: March 2010

Surface sediment samples from 10 coastal locations were analyzed with respect to their physical and chemical characteristics as well as their biological quality. The toxicity of the decanted fresh and freeze-dried sediments and of their elutriates was assessed by bioassays with embryos of the oysters Crassostrea gigas. The concentration inhibiting normal embryogenesis in 20% of the larvae (EC20) was used as a measure of toxicity and compared with the physical and chemical properties of the sediments and elutriates by principal components analysis. Decanted whole sediments were one to four orders of magnitude more toxic than their elutriates because the latter have lower contaminant concentrations. The biological effects of decanted whole sediment depended mostly on the levels of heavy metals and polycyclic aromatic hydrocarbons (PAHs), while in the case of the elutriates, the toxicity was mainly correlated with the concentrations of total ammonia and of dissolved organic carbon (DOC). Freeze-dried sediments and their elutriates were up to one order of magnitude more toxic than fresh sediments and elutriates, respectively, presumably because the freeze-drying procedure increases pollutant bioavailability or causes a release of unidentified organic compounds having toxic effects.
Timing of exposure to a pulp and paper effluent influences the manifestation of reproductive effects in rainbow trout
Authors: Van den Heuvel Michael R. , Ellis Rosanne J.
Published: March 2010

Rainbow trout were exposed to a secondary treated, thermomechanical/bleached kraft pulp and paper effluent in 12,000-L, flow-through exposure tanks at an environmental research facility located at a pulp and paper mill in Kawerau, New Zealand. Trout (age, 2+ years) were obtained from a local hatchery and exposed either to upstream river water or a nominal concentration of 12% (v/v) effluent diluted in upstream river water. Three treatment groups were used: Effluent exposure that started approximately three months before gonadal growth (eight-month total exposure), effluent exposure that started approximately halfway through gonadal development (two-month total exposure), and trout exposed to reference water alone for the total duration of the experiment. Trout were sacrificed just before spawning; exposure, growth, and reproductive endpoints were assessed during and at the termination of the experiment. Reduction in growth was observed in both sexes in the eight-month treatment group relative to the river water reference treatment group. No differences were observed in condition factor or liver size in either treatment. Females in the eightmonth exposure group also had significantly lower ovary weight. The two-month exposure group showed no differences from the reference group in growth or somatic indices. Estradiol and testosterone were reduced in blood samples taken from the eight-month exposure group by four months into the experiment as compared to the reference treatment. Steroid and vitellogenin levels in individual female trout from this treatment were significantly correlated with gonadosomatic indices (GSI) measured at the termination of the experiment. The GSI was not correlated strongly or consistently with pregnenolone, nor were any treatment-related pregnenolone differences observed, indicating that the steroid hormone reductions likely were not related to cholesterol side-chain cleavage. Male trout showed significant induction of vitellogenin and lower 11-ketotestosterone during the experiment (only the eight-month group was examined), but this did not result in any significant differences in testes development. Thus, this study has shown an impact of pulp mill effluent exposure on the reproductive physiology of female trout that appeared to be hormonally mediated. Furthermore, the effect could only be manifest when the exposure was initiated before the start of gonad development.
Influence of trophic position on organochlorine concentrations and compositional patterns in a marine food web
Authors: Ruus Anders , Ugland Karl Inne , Skaare Janneche Utne
Published: March 2010

The accumulation of polychlorinated biphenyls (PCBs), DDTs (p,p′-DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], o,p′-DDT [1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane], p,p′-DDD [1,1-dichloro-2,2-bis(4-chlorophenyl)ethane], o,p′-DDD [1,1-dichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane], and p,p′-DDE [1,1-dichloro-2,2-bis(4-chlorophenyl)ethene]), chlordanes (trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor and oxychlordane), hexachlorocyclohexanes (α-, β-, and γ-isomers), hexachlorobenzene, and mirex was investigated in a marine food web from southeastern Norway. The food web consisted of the polychaete Nereis diversicolor, lesser sandeel (Ammodytes tobianus), three species of gobys (Gobiusculus flavescens, Pomatoschistus sp., and Gobius niger), bullrout (Myoxocephalus scorpius), cod (Gadus morhua), herring gull (Larus argentatus), and harbor seal (Phoca vitulina). The results show that interspecies differences in organochlorine (OC) compositional patterns in the food web depend on several factors (allometric, biochemical, physical, and physicochemical) specific to both the chemicals and the organisms. The importance of dietary accumulation and metabolic capacity increases toward higher trophic levels, while the OC patterns are to a larger extent determined by the lipophilicity and water solubility of the compounds at lower trophic levels. Furthermore, stable nitrogen isotopes provided a continuous measure of trophic position, rendering us capable of quantifying the increases in the concentrations of ΣPCB, Σdichorodiphenyltrichloroethane (DDT), and Σchlordane (CHL) and the percentages of highly chlorinated PCBs through the food web. The information provided may be important for future modeling of the fate of organochlorine contaminants in marine food webs.
Evaluation of reduced sediment volume toxicity test procedures using the marine amphipod Ampelisca abdita
Authors: Ferretti James A. , Calesso Diane F. , Lazorchak James M. , Durham Curtis O.
Published: March 2010

During the past 20 years, the role of sediment toxicity tests has expanded from testing of primarily dredged material to risk assessment, decontamination technologies, large-scale regional sediment-quality assessments, and toxicity identification evaluations. Sediment toxicity tests are needed that can provide reliable data using less sediment and smaller test chambers, thus utilizing resources more efficiently. We compared survival results from 10-d standard marine amphipod tests at 20°C using 200 ml of sediment to reduced-volume tests containing 20 or 50 ml of sediment and found no significant differences. Similar survival also was observed in tests conducted for 7-d at 23°C versus the standard 10-d exposure at 20°C. However, amphipod sensitivity was significantly less in reduced-volume tests conducted for only 4- or 7-d at 20°C. The 10-d sediment toxicity tests using 50 ml of sediment provided comparable results to the standard protocol, whereas time for sampling, preparing, and sieving sediments for a test was substantially reduced.
17α-ethynylestradiol-induced vitellogenin gene transcription quantified in livers of adult males, larvae, and gills of fathead minnows (Pimephales promelas)
Authors: Lattier David L. , Reddy Tirumuru V. , Gordon Denise A. , Lazorchak James M. , Smith Mark E. , Williams Daniel E. , Wiechman Barry , Flick Robert W. , Miracle Ann L. , Toth Gregory P.
Published: March 2010

We have applied a method for quantifying relative levels of messenger RNA (mRNA) transcription to assess chemically induced gene expression in fathead minnows (Pimephales promelas). Synthetic oligonucleotides designed for the fathead minnow vitellogenin gene transcription product were used in a reverse transcription polymerase chain reaction (RT-PCR) protocol. This sensitive and rapid strategy detected vitellogenin gene transcription in livers of male fathead minnows exposed to concentrations as low as 2 ng/L of the endocrine-disrupting compound 17-α-ethynylestradiol for 24 h. Surprisingly, vitellogenin transcription products also were detected in gill tissue and in 48-h-old posthatch fathead minnow larvae. Relative levels of vitellogenin gene induction among individuals were quantified in a single-step reaction (PCR multiplex) with 18S rRNA universal primers and Competimerst concurrently with fathead minnow vitellogenin oligonucleotides. This quantitative approach will markedly enhance detection of the first cellular event of estrogenic exposure to aquatic ecosystems in both field and laboratory systems. Use of the model provides sensitivity of detection at a concentration below those that cause mortality or visible signs of stress in fish or other aquatic organisms. The model may also provide an in vivo screening method for estrogenlike endocrine-disrupting compounds.
Embryotoxic potential of persistent organic pollutants extracted from tissues of guillemots (Uria aalge) from the Baltic Sea and the Atlantic Ocean
Authors: De Roode Daphne F. , Gustavsson M. Bodil , Rantalainen Anna-lea , Klomp Anette V. , Koeman Jan H. , Bosveld Albertus T. C.
Published: March 2010

The Baltic Sea is a heavily polluted area. To assess the current contaminant pressure on the common guillemot (Uria aalge) living there, whole-body extracts of guillemots from the Baltic Sea were prepared and subdivided over six fractions, which differed in composition due to lipophilicity and polarity of the contaminants. The fractions were tested in the chicken embryo assay and compared to fractions of Atlantic guillemot extracts. Fertilized chicken eggs were injected with 0.03, 0.3, or 3 bird egg equivalents (BEQ) of the contaminants present in the fractions and then incubated for 19 d. Endpoints were selected to cover several mechanisms that may play a role in reproductive failures of fish-eating birds. Fractions I and IV from the Baltic guillemots induced ethoxyresorufin-O-deethylase (EROD) activity up to 15-fold in embryos exposed to 0.3 BEQ and up to 17-fold in embryos exposed to 3 BEQ. Corresponding Atlantic fractions induced EROD activity only at the higher dose of 3 BEQ. Morphological alterations were observed in the bursa of Fabricius in embryos exposed to the fractions that induced EROD, and for the Baltic fractions, this was apparent at the dose of 0.3 BEQ. The higher toxic potency of fractions I and IV was confirmed by higher mortality and occurrence of malformations among embryos exposed to these fractions. No other effects were observed; morphometry, hepatic porphyrin levels, thiamine-dependent enzymes, and acetylcholinesterase activity were not affected by any fraction. During interpretation of the results, concentrations in the whole-body guillemot extracts were compared to concentrations reported in field studies. In general, concentrations in the guillemot extract were lower than those associated with biomarker responses in other wildbird species. However, because the relative sensitivity of guillemot toward immunotoxic effects remains to be resolved, effects on the immunocompetence of guillemot could not be excluded.
In vitro assessment of potential mechanism-specific effects of polybrominated diphenyl ethers
Authors: Villeneuve Daniel L. , Kannan Kurunthachalam , Priest Benjamin T. , Giesy John P.
Published: March 2010

This study examined the ability of environmentally relevant concentrations of 10 different polybrominated diphenyl ethers (PBDEs) to induce aryl hydrocarbon receptor (AhR)-and estrogen receptor (ER)-mediated gene expression in vitro. It also examined the ability of PBDEs to displace steroid hormones from serum proteins in vitro. At concentrations ranging up to 880 ng/ml, none of the PBDEs significantly displaced tritiated 17β-estradiol (E2) or testosterone from hormone-stripped carp serum. At concentrations ranging up to 500 ng/ml, 9 of 10 PBDEs tested failed to induce ER- or AhR-mediated gene expression in MVLN and H4IIE-luc cells, respectively. One congener, 3,3′,4,4′,5-pentabromodiphenylether (BDE 126), induced significant AhR-mediated gene expression at 500 ng/ml, but the magnitude of induction was only 13% of that caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Overall, the PBDEs tested were found to be at least 200,000 times less potent than TCDD and 50,000 times less potent than E2 for inducing AhR- and ER-mediated gene expression, respectively.
Freshwater to saltwater toxicity extrapolation using species sensitivity distributions
Authors: Wheeler James R. , Leung Kenneth M. Y. , Morritt David , Sorokin Neal , Rogers Howard , Toy Robin , Holt Martin , Whitehouse Paul , Crane Mark
Published: March 2010

There is generally a lack of saltwater ecotoxicity data for risk assessment purposes, leaving an unknown margin of uncertainty in saltwater assessments that utilize surrogate freshwater data. Consequently, a need for sound scientific advice on the suitability of using freshwater data to extrapolate to saltwater effects exists. Here we use species sensitivity distributions to determine if freshwater datasets are adequately protective of saltwater species assemblages for 21 chemical substances. For ammonia and the metal compounds among these data, freshwater data were generally protective because freshwater organisms tended to be more sensitive. In contrast, for pesticide and narcotic compounds, saltwater species tended to be more sensitive and a suitable uncertainty factor would need to be applied to surrogate freshwater data. Biological and physicochemical factors contribute to such differences in freshwater and saltwater species sensitivities, but the species compositions of datasets used are also important.
A modeling approach to link food availability, growth, emergence, and reproduction for the midge Chironomus riparius
Authors: Péry Alexandre R. R. , Mons Raphaël , Flammarion Patrick , Lagadic Laurent , Garric Jeanne
Published: March 2010

We present models to link feeding with growth, emergence, and reproduction of the midge Chironomus riparius. These models are based on assumptions about the biology of this species and distinguish between males and females. The assumptions are the isomorphism of the chironomidae, the fact that much more energy is used for growth than for maintenance, and the existence of a maximum length for male and female larvae that does not depend on food availability. We supported our assumptions by experimental data and estimated the parameters of the model. We then successfully predicted the length pattern of 2-d-old larvae exposed in an artificial sediment to different feeding levels with different starting densities and also linked emergence time and growth pattern. We found our model to be consistent with data from another study and another species (Chironomus plumosus). As for reproduction, the mean number of eggs per mass was described as a linear function of feeding quantity. Our models could be used in sediment risk assessment to choose feeding level, to build effects models, or to predict the effects of toxicants at the population level.
The potential for estradiol and ethinylestradiol to sorb to suspended and bed sediments in some English rivers
Authors: Holthaus Karlijn I. E. , Johnson Andrew C. , Jürgens Monika D. , Williams Richard J. , Smith Jennifer J. L. , Carter Joy E.
Published: March 2010

The endocrine-disrupting impact of steroid estrogens on fish will be strongly influenced by their distribution between sediment and water. Laboratory studies were performed to investigate the potential for sorption of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) to bed and suspended sediments taken from five British rivers. Sediment material was collected from the Rivers Aire and Calder (located in urban and industrialized areas in Yorkshire, UK), the River Thames (at a relatively rural site in Oxfordshire, UK), and from the estuaries of the Rivers Tees and Tyne. Using anaerobic conditions to inhibit biodegradation, it was found that 80 to 90% of binding to bed sediments was complete within 1 d, but that an equilibrium had not been reached after 2 d. Bed sediments gave distribution coefficients (Kd) ranging from 4 to 74 L/kg for E2 and from 8 to 121 L/kg for EE2 for samples taken over a range of seasons and locations. Sorption to suspended sediment gave Kd values ranging from 21 to 122 L/kg for E2 and 19 to 260 L/kg for EE2. However, these Kd values suggest less than 1% removal of the steroid estrogens from the aqueous phase given the ambient suspended sediment concentration. In the bed sediments, higher Kd values were associated with smaller particle size and higher organic carbon content. In most cases, the Kd values obtained for EE2 were higher than those for E2 by a factor of up to three.
Improvement of a sensitive enzyme-linked immunosorbent assay for screening estrogen receptor binding activity
Authors: Koda Tomoko , Soya Yoshihiro , Negishi Harumi , Shiraishi Fujio , Morita MAsatoshi
Published: March 2010

A competitive enzyme-linked immunosorbent assay (ELISA) with estrogen receptor (a) and a fluorescence depolarization method with Full-Range Beacon were examined as estrogen receptor binding assays to prescreen endocrine-disrupting chemicals (EDCs). In this study, because it is difficult to measure the receptor binding ability of sparingly water-soluble chemicals using these methods, the competitive enzyme immunoassay was further modified for improved sensitivity by changing the operational parameters, such as receptor concentration, ligand concentration, and the reaction temperature. The method was applied to 10 test chemicals, including alkylphenols and bisphenol A (BPA). The diethylstilbestrol (DES) relative binding affinity (RBA) of ELISA kit was set equal to 1 (RBA = IC50/IC50 of DES). The RBAs of BPA, 4-nonylphenol (p-NP), and 4-t-octylphenol (p-t-OP) are 5386, 8619, and 8121 before using the improved competitive enzyme immunoassay and 883, 699, and 2832 using improved it respectively. Mixtures of BPA, p-NP, and p-t-OP gave results that the estrogen binding affinities of these chemicals are additive or slightly more than additive.
Concentrations and enantiomer fractions of organochlorine compounds in baltic species hit by reproductive impairment
Authors: Wiberg Karin , Bergman Anders , Olsson Mats , Roos Anna , Blomkvist Gun , Haglund Peter
Published: March 2010

Concentrations and enantiomer fractions (EFs) of organochlorine compounds (OCs) were determined in tissues of gray seal (Halichoerus grypus) and salmon (Salmo salar) originating from the Baltic Sea. The selected seal specimens ranged from starved to unstarved animals, and some of them suffered from a disease complex, while the salmon samples originated from individuals, which were known to produce offspring with and without the M74 syndrome. Significant differences in residue levels and EFs were found between seal groups but not between M74 salmon and non-M74 salmon. The relations between chemical and biological variables of seal samples were investigated with multivariate statistics. Poor health status correlated strongly with age, while bad nutrition condition was associated mainly with high pollution loads and distinctively nonracemic chiral OC compositions. High biotransformation rate (as indicated by fraction of chlordane metabolites in relation to total level of chlordanes) was also associated with large deviations from racemic values and high contaminant levels.
Using the dioxin receptor–calux in vitro bioassay to screen marine harbor sediments for compounds with a dioxin-like mode of action
Authors: Stronkhorst Joost , Leonards Pim , Murk Albertinka J.
Published: March 2010

The presence of dioxin-like compounds in sediments from harbors and reference sites along the Dutch coast was investigated using the dioxin receptor-chemically activated luciferase gene expression (DR-CALUX) bioassay. The DR-CALUX response varied between 0.2 and 136 ng/kg dry weight expressed in units of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency quotients (TEQ). The highest CALUX-TEQ values (>50 ng TEQ/kg dry wt) were found in sediments from the center of the Port of Rotterdam and from the North Sea canal near Amsterdam. The DR-CALUX activity of harbor sediments was classified by setting guideline values. None of the 257 harbor sediment samples investigated exceeded the maximum value of 1,000 ng TEQ/kg, while 94% of the samples fail the target value of 2 ng TEQ/kg. Threshold values (25 and 50 ng TEQ/kg) are intended as pass/fail criteria for offshore disposal of dredged material and were exceeded in 12 and 3% of the samples, respectively. DR-CALUX response did not always match with contamination of polychlorinated biphenyls (PCBs) as determined in bulk sediments (∑7-PCB ranging from <1 to 456 μg/kg dry wt). Concentrations of planar PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinateddibenzofuranes (PCDFs), polybrominated biphenyls (PBBs), and polybrominated-diphenylethers (PBDEs) were determined in 20 selected sediment extracts. On average, PCDD/Fs explained 50% of the DR-CALUX activity and planar PCBs 6%. Further research is needed to elucidate the unexplained part of the DR-CALUX response. The DR-CALUX is a highly sensitive and reproducible bioassay that can usefully complement standard PCB analysis, improving the hazard assessment of the disposal of dredged material in the North Sea.
The concept of persistence as applied to metals for aquatic hazard identification
Authors: Skeaff James M. , Dubreuil Alain A. , Brigham Sarah I.
Published: March 2010

The criteria persistence (P), bioaccumulation (B), and toxicity (T) are applied by domestic and international regulators and modelers to the hazard identification of chemical substances, including metals and metalloids, that may present harm to the environment. In this paper, we critically examine the literature to determine the weight of evidence for the application of water column partition half-times as a surrogate for the persistence criterion in the aquatic hazard identification of metals and metal compounds. Dissolved metals such as Fe, Mn, Cu, Pb, Co, Cs, Hg, and Zn, as well as the metalloids As and Se, tend to partition from the water column by adsorption onto sinking particulates, with reported and calculated partition half-times in the range 4 to 30 d, with outliers of 0.07 and 280 d. Within freshwater lakes, values of t1/2 for the transition metals Cr, Mn, Fe, Co, and Cu averaged about 10 d, while those for the nontransition metals Sr, Zn, Cs, and Hg and the metalloids As and Se varied up to 55 d. These data are consistent with the well-established complexing properties of the transition metals, which are significantly greater compared to the nontransition metals and the metalloids. While the considerable variations in the literature at present preclude the use of metal partition half-times in aquatic hazard identification, the surrogate for the persistence criterion could be the partition half-time of the bioavailable fraction of the total dissolved metal concentration as determined in a laboratory protocol under standardized conditions.
Degradation of chlorpyrifos, fenamiphos, and chlorothalonil alone and in combination and their effects on soil microbial activity
Authors: Singh Brajesh Kumar , Walker Allan , Wright Denis J.
Published: March 2010

The effects of repeated application and of combinations of pesticides on their degradation rates in soil and on some soil microbial properties were studied. Repeated application of chlorpyrifos did not modify its degradation rate, whereas repeated applications of fenamiphos and chlorothalonil suppressed their own rates of degradation. When applied in combination, the presence of chlorothalonil reduced the degradation rate of both chlorpyrifos and fenamiphos, and the half-life of chlorothalonil was extended in the presence of chlorpyrifos. The dynamics of residues of the major metabolites of the different compounds were also affected by the pesticide combinations and, particularly, by the presence of chlorothalonil. The measured soil microbial parameters (enzyme activities and total microbial biomass) were stable in the pesticide-free control soils throughout the 90-d incubation period, but they were all adversely affected by the presence of chlorothalonil in the soil. The effects from fenamiphos or chlorpyrifos on the soil microbial characteristics were either very small or insignificant.
Investigation of an onsite wastewater treatment system in sandy soil: Sorption and biodegradation of linear alkylbenzene sulfonate
Authors: Doi Jon , Marks Kay H. , Decarvalho Alvaro J. , McAvoy Drew C. , Nielsen Allen M. , Kravetz Louis , Cano Manuel L.
Published: March 2010

The objective of this work was to determine the sorptive and biodegradable characteristics of linear alkylbenzene sulfonate (LAS) in a soil below a Florida, USA, septic system drainfield. Three distinct soil samples were collected from the septic system drainfield study site. These soils were used in laboratory sorption and biodegradation studies. Different concentrations of LAS were added, in radiolabeled and unlabeled forms, to a series of test vessels that contained upgradient groundwater and the soils collected from the study site. The sorption test was designed to determine the partitioning of LAS between groundwater and soil in each sample. Results indicated that the sorption distribution coefficient (Kd) decreased from 4.02 to 0.43 L/kg and that the rate of ultimate biodegradation (first-order rate constant, k1) decreased from 2.17 to 0.08/d with increasing distance (0.7–1.2 m vertically below ground surface [BGS] and 0 to 6.1 m horizontally) from the drainfield. The three soils showed 49.8 to 83.4% LAS mineralization (percentage of theoretical CO2) over 45- or 59-d test periods. These results demonstrate that subsurface soils in this system have the potential to sorb and biodegrade LAS.
Effect of ethanol and methyl-Tert-butyl ether on monoaromatic hydrocarbon biodegradation: Response variability for different aquifer materials under various electron-accepting conditions
Authors: Ruiz-Aguilar Graciela M. L. , Fernandez-Sanchez Jose M. , Kane Staci R. , Kim Donguk , Alvarez Pedro J. J.
Published: March 2010

Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic hydrocarbon degradation under different electron-accepting conditions commonly found in contaminated sites experiencing natural attenuation. Response variability was investigated by using aquifer material from four sites with different exposure history. The lag phase prior to benzene, toluene, ethylbenzene, and xylenes (BTEX) and ethanol degradation was typically shorter in microcosms with previously contaminated aquifer material, although previous exposure did not always result in high degradation activity. Toluene was degraded in all aquifer materials and generally under a broader range of electron-accepting conditions compared to benzene, which was degraded only under aerobic conditions. The MtBE was not degraded within 100 d under any condition, and it did not affect BTEX or ethanol degradation patterns. Ethanol was often degraded before BTEX compounds and had a variable effect on BTEX degradation as a function of electron-accepting conditions and aquifer material source. An occasional enhancement of toluene degradation by ethanol occurred in denitrifying microcosms with unlimited nitrate; this may be attributable to the fortuitous growth of toluene-degrading bacteria during ethanol degradation. Nevertheless, experiments with flow-through aquifer columns showed that this beneficial effect could be eclipsed by an ethanol-driven depletion of electron acceptors, which significantly inhibited BTEX degradation and is probably the most important mechanism by which ethanol could hinder BTEX natural attenuation. A decrease in natural attenuation could increase the likelihood that BTEX compounds reach a receptor as well as the potential duration of exposure.
Degradation and persistence of metolachlor in soil: Effects of concentration, soil moisture, soil depth, and sterilization
Authors: Rice Pamela J. , Anderson Tood A. , Coats Joel R.
Published: March 2010

The present study evaluated the influence of soil depth, soil moisture, and concentration on the persistence and degradation of metolachlor in soil. Greater percentages of metolachlor persisted in subsurface soils than in surface soil regardless of the soil moisture or initial herbicide concentration. Larger quantities of bound residues and extractable degradation products were found in the surface soils as a result of the increased soil sorption and biodegradation of metolachlor associated with the surface soil, which had more organic matter. Saturated soil favored the dissipation of metolachlor and the formation of soil-bound residues. Significantly greater quantities of a dechlorinated metabolite were measured in the saturated surface soil compared to the unsaturated soil. Mineralization of metolachlor to CO2 and volatilization of metolachlor or metolachlor degradates was minimal in surface and subsurface soils at both soil moistures and herbicide concentrations. Increased metolachlor concentrations did not inhibit microbial activity; however, the greater rate of application did result in the reduced percentage of applied [14C]metolachlor that was bound to surface or subsurface soil. A significant reduction in the quantity of extractable metolachlor degradates and unextractable soilbound residues in sterile soil revealed the significance of biodegradation to the dissipation of metolachlor in soil.
Modeling the toxicity of polar and nonpolar narcotic compounds to luminescent bacterium Shk1
Authors: Ren Shijin , Frymier Paul D.
Published: March 2010

Luminescent bacterium Shk1 was created for the purpose of testing and screening the toxicity of activated sludge wastewater treatment plant influent to avoid toxic shock to the wastewater treatment plant microorganisms. The toxicity of a number of organic compounds was tested using an assay employing Shk1. Because these compounds exhibit toxicity by mechanisms of both polar and nonpolar narcosis, their toxicity cannot be properly modeled together using a quantitative structure-activity relationship model based on the logarithm of the octanol-water partition coefficient (log Kow). A solvation parameter model was developed to describe and predict the nonspecific (i.e., polar and nonpolar narcosis) toxicity of organic compounds to Shk1, which does not depend on the discrimination between polar and nonpolar narcotic compounds. The statistically significant model descriptors were the McGowan's characteristic volume (VX) and the hydrogen-bond basicity (∑βH). The model was similar to the solvation parameter model developed for Vibrio fischeri, but it did not include an excess molar refraction (R) term.
Biological availability of traffic-related platinum-group elements (palladium, platinum, and rhodium) and other metals to the zebra mussel (Dreissena polymorpha) in water containing road dust
Authors: Zimmermann Sonja , Alt Friedrich , Messerschmidt Jürgen , von Bohlen Alex , Taraschewski Horst , Sures Bernd
Published: March 2010

The uptake and bioaccumulation of 15 road dust metals by the zebra mussel (Dreissena polymorpha) were investigated in laboratory exposure studies with emphasis on the traffic-related platinum-group elements (PGEs) palladium (Pd), platinum (Pt), and rhodium (Rh). The biological availability of the metals may depend on water characteristics, so the mussels were maintained in two types of water: nonchlorinated tap water and humic water of a bog lake, both of which contained dust of a moderately frequented road. After an exposure period of 26 weeks, soft tissues of the mussels were freeze-dried and analyzed for the metals. The metal concentrations in the mussel soft tissue ranged from several hundred micrograms per gram (e.g., for iron [Fe]) to less than 10 ng/g (for PGEs). Metal uptake from the road dust by the mussels was found for the PGEs and silver (Ag), bismuth (Bi), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), Fe, lead (Pb), and antimony (Sb). After maintenance of mussels in road dust-contaminated tap water, bioaccumulation factors (BAF 5 (cexposed mussels - ccontrol mussels)/ctotal metal, water; where c is concentration) decreased in the following order: Cu > Cd > Ag > Pd > Sb > Pb > Fe > Pt > Rh. The biological availability of most metals was enhanced by humic water as compared to tap water. Our results show a hitherto unrecognized high availability of Pd for the mussels. Thus, this metal should be monitored more intensively in the environment to assess its distribution in the biosphere.