bluuebunny/crossref_metadata_2025 huggingface dataset:
Bioavailability of decabromodiphenyl ether to the marine polychaeteNereis virens
Authors: Klosterhaus Susan L. , Baker Joel E.
Published: March 2010

The flame retardant decabromodiphenyl ether (BDE 209) accumulates in humans and terrestrial food webs, but few studies have reported the accumulation of BDE 209 in aquatic biota. To investigate the mechanisms controlling the bioavailability of BDE 209, a 28-d bioaccumulation experiment was conducted in which the marine polychaete worm Nereis virens was exposed to a decabromodiphenyl ether (deca-BDE) commercial mixture (>85% BDE 209) in spiked sediments, in spiked food, or in field sediments. Bioaccumulation from spiked substrate with maximum bioavailability demonstrated that BDE 209 accumulates in this species. Bioavailability depends on the exposure conditions, however, because BDE 209 in field sediments did not accumulate (<0.3 ng/g wet weight; 28-d biota-sediment accumulation factors [BSAFs] <0.001). When exposed to deca-BDE in spiked sediments also containing lower brominated congeners (a penta-BDE mixture), bioaccumulation of BDE 209 was 30 times lower than when exposed to deca-BDE alone. Selective accumulation of the lower brominated congeners supports their prevalence in higher trophic level species. The mechanisms responsible for limited accumulation of BDE 209 may involve characteristics of the sediment matrix and low transfer efficiency in the digestive fluid. Environ. Toxicol. Chem. 2010;29:860–868. © 2009 SETAC
Quantifying the antiestrogen activity of wastewater treatment plant effluent using the yeast estrogen screen
Authors: Buckley James A.
Published: March 2010

The yeast estrogen screen (YES) assay was used to measure both estrogenic and antiestrogenic activity of wastewater treatment plant (WWTP) effluent for the purpose of developing a method to quantify antiestrogenic activity. Wastewater treatment plant effluent samples were concentrated by solid-phase extraction (SPE) and serially diluted. Five microliters of each dilution plus 195 µl of assay medium was placed in well plates and tested for estrogenic substances. Antiestrogen activity in WWTP effluent samples was indirectly measured by an effluent-volume–dependent suppression of the β-galactosidase activity induced by an estradiol (E2) standard. Antiestrogens and estrogens were quantified by median inhibition concentration (IC50) and median effective concentration (EC50) statistics, respectively, and were expressed in terms of effluent volume (prior to concentration by SPE). Antiestrogen IC50 and estrogen EC50 values, calculated by standard linear regression methods, averaged 25.6 µl and 22.1 µl effluent, respectively. Taken together, these values suggest that antiestrogens were responsible for approximately a 50% reduction in estrogen-induced activity in WWTP effluent. Therefore, measurements of estrogenicity by the YES assay in WWTP effluent that typically contains a mixture of estrogenic and antiestrogenic substances should be considered net estrogenic activity. The potential for false-positive antiestrogen activity was addressed by assays of β-galactosidase activity in effluent, by measurements of yeast cell turbidity, and by stirred cell ultrafiltration for removal of solid-phase coextracted organic substances. Environ. Toxicol. Chem. 2010;29:73–78. © 2009 SETAC
Spatial patterns of atmospherically deposited organic contaminants at high elevation in the southern Sierra Nevada mountains, California, USA
Authors: Bradford David F. , Stanley Kerri , McConnell Laura L. , Tallent-Halsell Nita G. , Nash Maliha S. , Simonich Staci M.
Published: March 2010

Atmospherically deposited contaminants in the Sierra Nevada mountains of California, USA have been implicated as adversely affecting amphibians and fish, yet little is known about the distributions of contaminants within the mountains, particularly at high elevation. The hypothesis that contaminant concentrations in a high-elevation portion of the Sierra Nevada decrease with distance from the adjacent San Joaquin Valley was tested. Air, sediment, and tadpoles were sampled twice at 28 water bodies in 14 dispersed areas in Sequoia and Kings Canyon National Parks (2,785–3,375 m elevation; 43–82 km from Valley edge). Up to 15 chemicals were detected frequently in sediment and tadpoles, including current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Only β-endosulfan was found frequently in air. Concentrations of all chemicals detected were very low, averaging in the parts-per-billion range or less in sediment and tadpoles, and on the order of 10 pg/m3 for β-endosulfan in air. Principal components analysis indicated that chemical compositions were generally similar among sites, suggesting that chemical transport patterns were likewise similar among sites. In contrast, transport processes did not appear to strongly influence concentration differences among sites, because variation in concentrations among nearby sites was high relative to sites far from each other. Moreover, a general relationship for concentrations as a function of distance from the valley was not evident across chemical, medium, and time. Nevertheless, concentrations for some chemical/medium/time combinations showed significant negative relationships with metrics for distance from the Valley. However, the magnitude of these distance effects among high-elevation sites was small relative to differences found in other studies between the valley edge and the nearest high-elevation sites. Environ. Toxicol. Chem. 2010;29:1056–1066. © 2010 SETAC
Relationship between laying sequence and mercury concentration in tree swallow eggs
Authors: Brasso Rebecka L. , Abdel Latif Marwa K. , Cristol Daniel A.
Published: March 2010

When female birds lay eggs, some of their body burden of mercury is eliminated into each egg, potentially leading to declining mercury across the clutch. However, there was no decline in mercury with laying sequence in clutches of tree swallow (Tachycineta bicolor) eggs at a mercury-contaminated site, presumably due to daily replenishment of mercury in females during laying. Sampling just one egg from the nest provided an accurate measure of clutch mercury contamination. Environ. Toxicol. Chem. 2010;29:1155–1159. © 2010 SETAC
Extent of copper tolerance and consequences for functional stability of the ammonia-oxidizing community in long-term copper-contaminated soils
Authors: Mertens Jelle , Wakelin Steven A. , Broos Kris , McLaughlin Mike J. , Smolders Erik
Published: March 2010

Adaptation of soil microbial communities to elevated copper (Cu) concentrations has been well documented. However, effects of long-term Cu exposure on adaptation responses associated with functional stability and structural composition within the nitrifying community are still unknown. Soils were sampled in three field sites (Denmark, Thailand, and Australia) where Cu gradients had been established from 3 to 80 years prior to sampling. In each field site, the potential nitrification rate (PNR) decreased by over 50% with increasing soil Cu, irrespective of a 20 to >200-fold increase in Cu tolerance (at the highest soil Cu) among the nitrifying communities. This increased tolerance was associated with decreasing numbers (15–120-fold) of ammonia-oxidizing bacteria (AOB), except in the oldest contaminated field site, decreasing numbers of ammonia-oxidizing archaea (AOA; 10–130-fold) and differences in the operational taxonomic unit (OTU) composition of the AOB and, to a lesser extent, AOA communities. The sensitivity of nitrifying communities, previously under long-term Cu exposure, to additional stresses was assessed. Nitrification in soils from the three field sites was measured following acidification, pesticide addition, freeze–thaw cycles, and dry–rewetting cycles. Functional stability of the nitrification process was assessed immediately after stress application (resistance) and after an additional three weeks of incubation (resilience). No indications were found that long-term Cu exposure affected the sensitivity to the selected stressors, suggesting that resistance and resilience were unaffected. It was concluded that the nitrifying community changed structurally in all long-term Cu-exposed field sites and that these changes were associated with increased Cu tolerance but not with a loss of functional stability. Environ. Toxicol. Chem. 2010;29:27–37. © 2009 SETAC
Toxicities of fipronil enantiomers to the honeybee Apis mellifera L. and enantiomeric compositions of fipronil in honey plant flowers
Authors: Li Xiqing , Bao Chen , Yang Daibin , Zheng Mingqi , Li Xuefeng , Tao Shu
Published: March 2010

Fipronil is a chiral phenylpyrazole insecticide that is effective for control of a wide range of agricultural and domestic pests at low application rates. Wide application of fipronil also causes poisoning of some nontarget insects, such as honeybees. In the present study, toxicities of fipronil enantiomers and racemate to the honeybee Apis mellifera L. were determined to examine whether using formulations of single or enriched fipronil enantiomer is a possible option to reduce risks to bees. Contact toxicity tests yielded median lethal doses (LD50) of 3.45, 3.38, and 3.86 ng/bee for the R(−)-enantiomer, S(+)-enantiomer, and racemate, respectively. Analysis of variance indicates that the LD50 values are not statistically different (p = 0.41). Oral toxicities of the R-enantiomer, S-enantiomer, and racemate (nominal median lethal concentration = 0.037, 0.045, 0.053 mg/L, respectively) were also demonstrated to be not statistically different (p = 0.20). In addition, enantiomeric fractions of fipronil in the flowers of three honey plants (Brassica campestris, Cucumis sativus, and Chrysanthemum indicum L.) were examined after treatment with fipronil. It was found that degradation of fipronil in all three plants is not enantioselective. These results indicate that it is unlikely that use of formulations with single or enriched fipronil enantiomer would reduce the risk that fipronil poses to honeybees. Improved fipronil application practices (based on safest timing and bloom conditions) and reduction of overall fipronil usage seem to be more realistic options. Environ. Toxicol. Chem. 2010;29:127–132. © 2009 SETAC
Binding of ciprofloxacin by humic substances: A molecular dynamics study
Authors: Aristilde Ludmilla , Sposito Garrison
Published: March 2010

A comprehensive assessment of the potential impacts of antimicrobials released into the environment requires an understanding of their sequestration by natural particles. Of particular interest are the strong interactions of antimicrobials with natural organic matter (NOM), which are believed to reduce their bioavailability, retard their abiotic and biotic degradation, and facilitate their persistence in soils and aquatic sediments. Molecular dynamics (MD) relaxation studies of a widely used fluoroquinolone antibiotic, ciprofloxacin (Cipro), interacting with a model humic substance (HS) in a hydrated environment, were performed to elucidate the mechanisms of these interactions. Specifically, a zwitterionic Cipro molecule, the predominant species at circumneutral pH, was reacted either with protonated HS or deprotonated HS bearing Ca, Mg, or Fe(II) cations. The HS underwent conformational changes through rearrangements of its hydrophobic and hydrophilic regions and disruption of its intramolecular H-bonds to facilitate favorable intermolecular H-bonding interactions with Cipro. Complexation of the metal cations with HS carboxylates appeared to impede binding of the positively charged amino group of Cipro with these negatively charged HS complexation sites. On the other hand, an outer-sphere complex between Cipro and the HS-bound cation led to ternary Cipro–metal–HS complexes in the case of Mg–HS and Fe(II)–HS, but no such bridging interaction occurred with Ca–HS. The results suggested that the ionic potential (valence/ionic radius) of the divalent cation may be a determining factor in the formation of the ternary complex, with high ionic potential favoring the bridging interaction. Environ. Toxicol. Chem. 2010;29:90–98. © 2009 SETAC
Identifying the causes of sediment-associated contamination in the Illinois River (USA) using a whole-sediment toxicity identification evaluation
Authors: Mehler W. Tyler , Maul Jonathan D. , You Jing , Lydy Michael J.
Published: March 2010

Whole-sediment toxicity identification evaluation (TIE) techniques were employed on the Illinois River Complex (IRC), USA to identify the sources of sediment toxicity that may have contributed to the decline in benthic invertebrate populations. The TIE focused on three classes of contaminants: ammonia, metals, and organics. Sediment toxicity was assessed using the amphipod Hyalella azteca, and the focus of the TIE was on assessing spatial and temporal patterns of contamination. Past studies suggested that ammonia was the major source of contamination in IRC sediments. However, the present study suggested that polycyclic aromatic hydrocarbons (PAHs) were the primary contributor to sediment toxicity. Phase I testing showed 46% of the site trials (12 of 26) exhibited increased H. azteca survival (p < 0.05) with the addition of powdered coconut charcoal (organic amendment), whereas zeolite (ammonia amendment) and Resin Tech SIR 300 (cationic metals amendment) did not increase H. azteca survival. Phase II testing revealed PAH concentrations were high enough to cause the observed toxicity, confirming phase I results. Spatially, sediment toxicity as well as pore-water ammonia concentrations declined with distance downstream from suspected contaminant sources, indicating a potential dilution or remedial effect. Temporally, pore-water ammonia, metals, and PAH concentrations varied among sampling periods over an annual cycle for some sites near urbanized areas, while remaining temporally consistent at others. The results of the present study provide new information on the sources of toxicity within the IRC, and demonstrate the importance of evaluating spatial and temporal aspects in sediment TIEs. This is particularly important for evaluations in riverine systems in which hydrologic processes can result in large variation in sediment toxicity on temporal and spatial scales. Environ. Toxicol. Chem. 2010;29:158–167. © 2009 SETAC
Hierarchical cluster analysis of polychlorinated dioxins and furans in Michigan, USA, soils: Evaluation of industrial and background congener profiles
Authors: Towey Timothy P. , Chang Shu-Chi , Demond Avery , Wright Daniel , Barabás Noémi , Franzblau Alfred , Garabrant David H. , Gillespie Brenda W. , Lepkowski James , Luksemburg William , Adriaens Peter
Published: March 2010

As part of the University of Michigan Dioxin Exposure Study, soil samples were collected from 766 residential properties near the Tittabawassee River between Midland and Saginaw; near the Dow Chemical Facility in Midland; and, for comparison, in the other areas of Midland and Saginaw Counties and in Jackson and Calhoun Counties, all located in the state of Michigan, USA. A total of 2,081 soil samples were analyzed for 17 polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). In order to better understand the distribution and sources of the PCDD/F congeners in the study area, hierarchical cluster analysis (HCA) was used to statistically group samples with similar congener patterns. The analysis yielded a total of 13 clusters, including: 3 clusters among the soils impacted by contamination present in the Tittabawassee River sediments, a cluster comprised mainly of samples collected within the depositional area of the Dow incinerator complex, a small cluster of samples with elevated 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD), and several clusters exhibiting background patterns. The clusters related to the Tittabawassee River floodplain contamination all contained elevated PCDF levels and were differentiated from one another primarily by their relative concentrations of higher-chlorinated PCDDs, a difference likely related to both extent and timing of impacts from Tittabawassee sediments. The background clusters appear to be related to combustion processes and are differentiated, in part, by their relative fractions of TCDD. Thus, HCA was useful for identifying congener profile characteristics in both contaminated and background soil samples. Environ. Toxicol. Chem. 2010;29:64–72. © 2009 SETAC
Effects of dietary cadmium exposure on reproduction of saltwater cladoceran Moina monogolica Daday: Implications in water quality criteria
Authors: Wang Zaosheng , Yan Changzhou , Hyne Ross V.
Published: March 2010

The chronic toxicity of dietary cadmium to the saltwater cladoceran Moina monogolica Daday and its relative toxicity compared with aquatic exposure were investigated in the present study. The microalgae Chlorella pyrenoidosa, exposed to cadmium in growth inhibition tests, had a 96-h median effective concentration (EC50) of 81.2 µg Cd/L (95% confidence intervals [CIs] = 71.9–95.1). C. pyrenoidosa exposed for 96 h to sublethal dissolved cadmium concentrations in the range 4.10 ± 0.30 to 70.29 ± 0.31 µg/L resulted in algal cadmium burdens up to 73.86 × 10−16 g Cd/cell. Cellular cadmium burdens accumulated in a dose-dependent manner, whereas cell densities inversely declined from 670 × 104 to 38 × 104 cells/ml with exposure to the increasing aqueous cadmium concentrations. C. pyrenoidosa preexposed to cadmium and used as food in a chronic 21-d toxicity test with the cladoceran M. monogolica, containing no added dissolved cadmium, inhibited reproduction. Significant reductions of the net reproduction rate (R0) per brood were observed in all broods, and the decline in the number of neonates produced increased with each subsequent brood. The cadmium concentration (4.10 ± 0.30 µg/L) in the algal culture water that produced the lowest algal cadmium burden (2.85 ± 0.76 × 10−16 g Cd/cell) was shown to inhibit M. monogolica reproduction and was compared with the water quality criteria (WQC) of China. This comparison indicated that dietary exposure to cadmium may cause sublethal responses at concentrations below the current cadmium WQC of China for aquaculture. Environ. Toxicol. Chem. 2010;29:365–372. © 2009 SETAC
Effects of environmental regimens on the toxin profile of Alexandrium ostenfeldii
Authors: Otero Paz , Alfonso Amparo , Vieytes Mercedes R. , Cabado Ana G. , Vieites Juan M. , Botana Luis M.
Published: March 2010

Environmental conditions are key factors in the development of marine toxic phytoplankton. Spirolides are marine toxins with a heptacyclic imine ring responsible for the toxicity in mice. Alexandrium ostenfeldii (A. ostenfeldii) is the main producer of these toxins, although this dinoflagellate often produces toxins belonging to the paralytic shellfish poisoning (PSP) group. The present study shows the first evidence that external environmental factors can influence the toxin profile produced by the dinoflagellate A. ostenfeldii. The species investigated is indigenous to the North Atlantic coast, and their cells grew under several environmental parameters. Toxin production was measured by means of liquid chromatography-mass spectrometry (LC-MS) and the chromatograms reflect the presence of two spirolides in all cultures; one in the region m/z 692.5, corresponding to 13-desmethyl spirolide C (13-desMeC) and the other in the region m/z 678.5, which corresponds to 13,19-didesmethyl spirolide C (13,19-didesMeC). The physical parameters studied were salinity, culture media, and photoperiod. The highest amount of toxin per cell was obtained when dinoflagellates grew in F/2 and Walne medium, 28‰ salinity, and 24 h of light. However, the highest proportion of 13,19-didesMeC with respect to 13-desMeC was achieved in L1 medium, 33‰ salinity, and 14:10 h light:dark. On the contrary, the highest proportion of 13-desMeC in cells was obtained when A. ostenfeldii was cultured in F/2 medium, 28‰ salinity, and the same photoperiod. Therefore, from these data the optimum conditions to culture A. ostenfeldii and to obtain the highest amount of spirolide per cell are shown. In addition, these environmental conditions can be considered a tool to predict and avoid A. ostenfeldii blooms. Environ. Toxicol. Chem. 2010;29:301–310. © 2009 SETAC
Evaluation of metal toxicity by a modified method based on the fungus Gerronema viridilucens bioluminescence in agar medium
Authors: Mendes Luiz Fernando , Stevani Cassius Vinicius
Published: March 2010

Metal cation toxicity to basidiomycete fungi is poorly understood, despite its well-known importance in terrestrial ecosystems. Moreover, there is no reported methodology for the routine evaluation of metal toxicity to basidiomycetes. In the present study, we describe the development of a procedure to assess the acute toxicity of metal cations (Na+, K+, Li+, Ca2+,Mg2+, Co2+, Zn2+, Ni2+, Mn2+, Cd2+, and Cu2+) to the bioluminescent basidiomycete fungus Gerronema viridilucens. The method is based on the decrease in the intensity of bioluminescence resulting from injuries sustained by the fungus mycelium exposed to either essential or nonessential metal toxicants. The assay described herein enables us to propose a metal toxicity series to Gerronema viridilucens based on data obtained from the bioluminescence intensity (median effective concentration [EC50] values) versus metal concentration: Cd2+ > Cu2+ > Mn2+ ≈ Ni2+ ≈ Co2+ > Zn2+ > Mg2+ > Li+ > K+ ≈ Na+ > Ca2+, and to shed some light on the mechanism of toxic action of metal cations to basidiomycete fungi. Environ. Toxicol. Chem. 2010;29:320–326. © 2009 SETAC
C-fin: A cultured frog tadpole tail fin biopsy approach for detection of thyroid hormone-disrupting chemicals
Authors: Hinther Ashley , Domanski Dominik , Vawda Saadia , Helbing Caren C.
Published: March 2010

There is a need for the development of a rapid method for identifying chemicals that disrupt thyroid hormone (TH) action while maintaining complex tissue structure and biological variation. Moreover, no assay to date allows a simultaneous screen of an individual's response to multiple chemicals. A cultured tail fin biopsy or C-fin assay was developed using Rana catesbeiana tadpoles. Multiple tail fin biopsies were taken per tadpole, cultured in serum-free medium, and then each biopsy was exposed to a different treatment condition. The effects of known disruptors of TH action were evaluated in the C-fin assay. Chemical exposure was performed ± 10 nM 3,3′,5-triiodothyronine and real-time quantitative polymerase chain reaction (QPCR) of two TH-responsive transcripts, TH receptor β (TRβ) and the Rana larval keratin type I (RLKI), was performed. Within 48 h of exposure to Triac (1-100 nM), roscovitine (0.6–60 µM), or genistein (1–100 µM), perturbations in TH signaling were detected. Tetrabromobisphenol A (TBBPA) (10-1,000 nM) showed no effect. Acetochlor (1–100 nM) elicited a modest effect on the TH-dependent induction of TRβ transcript. These data reveal that a direct tissue effect may not be critical for TBBPA and acetochlor to disrupt TH action previously observed in intact tadpoles. Environ. Toxicol. Chem. 2010;29:380–388. © 2009 SETAC
Ranking sediment samples from three Spanish estuaries in relation to its toxicity for two benthic species: The microalga Cylindrotheca closterium and the copepod Tisbe battagliai
Authors: Araújo Cristiano V.M. , Diz Fernando R. , Tornero Victoria , Lubián Luís M. , Blasco Julián , Moreno-Garrido Ignacio
Published: March 2010

The present study assesses the sediment toxicity levels of three Spanish estuaries, as well as the suitability of two microorganisms, the benthic microalga Cylindrotheca closterium and the harpacticoid copepod Tisbe battagliai, as test organisms in whole-sediment toxicity assays. The sensitivity of both species to potentially polluted sediments was compared. Three sites at the southwest of the Iberian Peninsula were chosen: the Ría of Huelva, the Guadalquivir Estuary, and the Bay of Algeciras. Inhibition data were based on growth for C. closterium and fecundity for T. battagliai. No toxicity was recorded for the microalga in the Guadalquivir Estuary and the Bay of Algeciras. However, for T. battagliai, inhibition of fecundity was approximately 50% in those zones, indicating higher sensitivity. Samples from stations in the Ría of Huelva were the most toxic of all those assayed; inhibition values higher than 90% were obtained for both organisms. The highest values for total metal concentrations such as arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), tin (Sn), and zinc (Zn) were found in the Ría of Huelva, which can be classified as severely impacted. The Guadalquivir Estuary and the Bay of Algeciras can be considered moderately impacted. In general, both methodologies are suitable for application in ecotoxicological studies. Environ. Toxicol. Chem. 2010;29:393–400. © 2009 SETAC
Cry1Ab toxin production of MON 810 transgenic maize
Authors: Székács András , Lauber Éva , Juracsek Judit , Darvas Béla
Published: March 2010

Levels of Cry1Ab toxin were detected in genetically modified maize of genetic event MON 810 against near isogenic maize as negative control by two commercial immunoassays. The immunoassays were characterized for their cross-reactivity (CR) between Cry1Ab protoxin and activated toxin, and were compared with each other for toxin detection in a reference plant sample. Cry1Ab toxin levels, corrected for active toxin content using the CR values obtained, were monitored in maize DK-440 BTY through the entire vegetation period. The toxin concentration was found to show a rapid rise in the leaves to 17.15 ± 1.66 µg/g by the end of the fifth week of cultivation, followed by a gradual decline to 9.61 ± 2.07 µg/g by the 16th week and a slight increase again to 13.51 ± 1.96 µg/g during the last 2 weeks due to partial desiccation. Similar but lesser fluctuation of toxin levels was seen in the roots between 5.32 ± 0.49 µg/g at the less differentiated V1 stage and 2.25 ± 0.30 µg/g during plant development. In contrast, Cry1Ab toxin levels appeared to be stably 1.36 ± 0.45, 4.98 ± 0.31, 0.47 ± 0.03, and 0.83 ± 0.15 µg/g in the stem, anther wall, pollen, and grain, respectively. Toxin concentrations produced at the VT-R4 phenological stages under actual cultivation conditions were compared with each other in three different years within an 8-year period. Environ. Toxicol. Chem. 2010;29:182–190. © 2009 SETAC
Copper toxicity thresholds in Chinese soils based on substrate-induced nitrification assay
Authors: Li Xiao-Fang , Sun Jin-Wei , Huang Yi-Zong , Ma Yi-Bing , Zhu Yong-Guan
Published: March 2010

Copper toxicity in 17 Chinese soils was screened using a substrate-induced nitrification assay to generate information for the development of a terrestrial biotic ligand model (tBLM). The leaching effect on the Cu toxicity thresholds was investigated. Both the total Cu-based median effective concentration (EC50) values (46.9–2726 mg/kg) and the solution Cu-based EC50 values (0.04–2.91 mg/L) in unleached soils varied substantially among the soils in the present study. For unleached soils, linear stepwise multiple regression analysis showed that total Ca and soil pH were the best predictors for total Cu-based EC50, while electrical conductivity (EC) and soil pH were the best predictors for solution Cu-based EC50. The variation in solution Cu-based EC50 was largely (R2 = 0.75) explained by Mg but not Ca and H+ concentration in soil solution at EC50, suggesting a protective effect of Mg2+ against Cu toxicity in the test soils. Leaching impacted Cu toxicity differently among the soils and apparently reduced the variations of both the total Cu-based and the solution Cu-based EC50. The predictability of the Cu EC50 by empirical models was decreased after leaching. The leaching effect on Cu toxicity, indicated by a leaching factor, was not predicted by any soil properties. There is a need to investigate quantitatively the mechanisms for the leaching effect on Cu toxicity in soils. Environ. Toxicol. Chem. 2010;29:294–300. © 2009 SETAC
Anticholinesterase poisoning of birds: Field monitoring and diagnosis of acute poisoning
Authors: Hill Elwood F. , Fleming W. James
Published: March 2010

Organophosphorus and carbamate pesticides are cholinesterase (ChE) inhibiting chemicals that have been responsible for avian die-offs. Identification of chemicals implicated in these die-offs is difficult and sometimes conclusions are solely circumstantial. However, when marked depression (inhibition) of brain ChE activity accompanies organophosphorus or carbamate residues in body tissues or ingesta, cause-effect diagnosis is enhanced. To achieve this end, normal brain ChE activity is estimated for controls of the affected species and then die-off specimens are individually evaluated for evidence of ChE inhibition. This approach to evaluation of antiChE poisoning may also be used to monitor exposure of vertebrates to field application of organophosphorus or carbamate pesticides. Problems associated with this kind of evaluation, and the main topic of this report, include variability of brain ChE activity among species, postmortem influences of ambient conditions (storage or field) on ChE activity, and differential patterns of ChE activity when inhibited by organophosphorus or carbamate compounds. Other topics discussed are the ChE assay procedure, example case reports and interpretation, and research needed for improving the diagnostic utility of ChE activity in a field situation.
Which components of crude oil are toxic to young seabirds?
Authors: Miller D. S. , Hallett D. J. , Peakall D. B.
Published: March 2010

Studies from this laboratory have focused on sublethal physiological effects of small amounts of ingested crude oil in young herring gulls (Larus argentatus). Clearly, the most striking effect of certain oils in gulls is the marked reduction in rates of weight gain found after administration of a single 0.2–1 ml oral dose. For example, dosing with one South Lousiana crude (obtained from the American Petroleum Institute in 1976; SLC-76) reduced weight gain by 40–80%; another SLC, obtained in 1978, had no effect. Gas chromatographic-mass spectrographic analyses of the oils indicated that SLC-1978 lacked certain aromatics. Weathering of SLC-76 over sea water for 36 h did not reduce its ability to inhibit weight gain in gulls. Both findings implicated higher weight aromatics as the active compounds. SLC-76 was split on an alumina column into aliphatic and aromatic fractions; only the aromatic fraction reduced gull rates of weight gain. Using a Prudhoe Bay crude (as toxic to gulls as SLC-76), the aromatic fraction was split into two subfractions on Sephadex LH-20. Analyses showed that one subfraction contained those aromatics with three or less rings and the other contained those with four or more rings. Only the second fraction (high molecular weight aromatics) reduced gull weight gain. These findings clearly show that oil composition is a major determinant of oral toxicity to young seabirds, and that the higher molecular weight aromatics are most effective in reducing gull weight gain.
Hydrolysis and oxidation processes in the environment
Authors: Mill Theodore
Published: March 2010

Many kinds of chemical structures can undergo hydrolysis under conditions typically found in freshwater and marine systems with rates that are fast enough to make these reactions the dominant loss processes. Methods for estimating rate constants from structural activity relationships (SAR) and for measuring hydrolysis rate constants in the laboratory will be discussed as will limitations and complications in these procedures.

Oxidations of organic structures by HO radical in the atmosphere and by RO2 and singlet oxygen in water are complex processes ultimately driven by sunlight. In air oxidation is the single most important loss process; in water only a few classes of organic structures are readily oxidized. The principles governing these photooxidations, SAR for estimating rate constants and available laboratory methods for their measurement will be discussed.
Wildlife toxicity studies with oxamyl
Authors: Smith Ladd W.
Published: March 2010

The acute oral LD50 of oxamyl in bobwhite (Colinus virginianus), mallards (Anas platyrhnchos) and Japanese quail (Coturnix c. japonica) is 9.4, 2.6 and 4.3 mg/kg BW, respectively. The eight-day dietary LC50 in bobwhite and mallards is 54 and 369 ppm, respectively. When Japanese quail consumed up to 33 mg oxamyl/kg BW/day over a 30-day intermittent feeding period, no effects were evident. When bobwhite and rabbits were oversprayed with oxamyl under field conditions (three times at 3 pounds per acre), no clinical or gross pathological effects were produced.
Use of isolated perfused lung in determining pulmonary disposition and potential toxicological significance of inhaled environmental pollutants
Authors: Mehendale Harihara M.
Published: March 2010

Recent interest in the investigation of the effect of environmental pollutants on the nonrespiratory and respiratory functions of the lung has stimulated the refinement and application of the technique of perfusing isolated intact lung preparations from suitable experimental animals in toxicological and biochemical studies. Available techniques include perfusion with whole blood or constituted perfusion media via pulmonary artery while maintaining ventilation with alternating negative or positive pressure. Viable, ventilating lung preparations can be maintained for 3 h. Such preparations have been employed for studies of uptake, metabolism and disposition of intratracheally or vascularly administered endogenous or exogenous chemicals. Recent development in unilateral or split-lung perfusion preparations will undoubtedly further enhance the application of these techniques in the study of the interactions of endogenous and exogenous substances in the lung tissue. Isolated, perfused split-lung preparations are particularly suited to investigate early toxic effects of inhaled pollutants in an attempt to gain insight into underlying mechanisms that lead to lung injury. Areas in which intact perfused lungs have been employed extensively with notable success include uptake, metabolism and disposition of toxic chemicals. These preparations have been used to study the effects of gases such as SO2, NO2, O3 and CO on lung metabolism. Perfused lung preparations have been particularly useful in demonstrating pulmonary activation of toxic chemicals and in the demonstration of specific effects on the lung after chronic administration of chemicals. Areas which have not been actively investigated include the uptake and disposition of gases or vapors, effects of toxic chemicals on respiratory and nonrespiratory functions of the lung and alteration in the hemodynamics of the pulmonary circulation in the presence of interacting chemical or physical agents. It should be technically feasible to adapt the perfused lung preparations for such investigations, and interest in this area will continue.
Carbofuran disposition in the rat after aerosol inhalation
Authors: Ferguson Paul W. , Jewell Sarah A. , Krieger Robert I. , Raabe Otto G.
Published: March 2010

[14C-]Carbonyl carbofuran toxicity, metabolism and pharmacokinetics in male Sprague-Dawley rats were studied after 4.1 μm (50 min, 0.2 and 1.2 μg/L) and 1.5 μm (70 min, 0.2 μg/L) aerodynamic diameter monodisperse aerosol exposures. Regional carbofuran deposition for each particle size was similar to human and rodent models for insoluble aerosols. Total carbofuran deposition was greater than expected in the rodent model but similar to that in human models.

3-Hydroxycarbofuran/carbofuran ratios in gastrointestinal tract and liver (1.3, 3 × greater after 4.1 μm) provided additional deposition indices. Rapid in vitro solubility t1/2 (17 min) for 4.1 μm particles and minimal differences in plasma carbamate (% total 14C/animal) after varied particle size exposure indicated primary clearance by dissolution, irrespective of deposition site. Carbofuran (1.2 μg/L, 4.1μm) inhibited red blood cell acetylcholinesterase (55% at 10 min postexposure with recovery by 2 h). Eight-hour 14C metabolic fate in 14CO2 (31–38%), urine (9–12%), feces (2–5.5%) and carcass (44–58%) were similar for each particle size. Carbamate pharmacokinetics measured for 2 h postexposure to 4.1 μm particles described monoexponential elimination. Plasma half-lives for carbofuran (36 min) and 3-hydroxycarbofuran (62 min) were similar to those previously determined after oral and i.v. exposures.
Use of aquatic toxicology and quantitative chemistry to estimate environmental deactivation of marine-grade creosote in seawater
Authors: Borthwick Patrick W. , Patrick James M.
Published: March 2010

The acute toxicity of marine-grade creosote, expressed as the 96-h LC50, is 0.018 mg/L for mysids (Mysidopsis bahia Molenock), 0.24 mg/L for pink shrimp (Penaeus duorarum Burken-road) and 0.72 mg/L for sheepshead minnows (Cyprinodon variegatus, Lacépède). The 96-h EC50 (shell deposition) for Eastern oysters (Crassostrea virginica Gmelin) is 0.71 mg/L. Mysid bioassays and chemical analyses estimate the half-life (≤ 1 week) for marine-grade creosote in seawater.
Effect on Daphnia pulex (de geer) of daily pulse exposures to copper or cadmium
Authors: Ingersoll Christopher G. , Winner Robert W.
Published: March 2010

The most recent U.S. EPA water quality criteria indicate that chronic exposures to pulses of the LC50 concentration of a metal will cause no damage to freshwater animals as long as the average daily concentration does not exceed the chronic, no-observable-effect concentration. We have tested this concept by exposing Daphnia pulex to such pulses of copper and cadmium. The exposures to cadmium for periods of up to 70d, caused no adverse effects. However, 70-d exposures to daily pulses of copper resulted in significant reductions in survival, growth and reproduction. Although the two-number criterion has not been tested for other chemicals, it is probable that the success of this approach in protecting freshwater animals from chronic exposures to chemicals will be as variable among other chemicals as we have shown it to be between copper and cadmium.
Seasonal patterns of sedimentary hydrocarbons in the raritan bay-lower new york bay
Authors: Stainken Dennis M. , Gray Multer H. , Mirecki June
Published: March 2010

Surface sediments from 24 stations in the Raritan Bay-lower New York Bay were analyzed seasonally for size-grade distributions, percent volatiles and extractable hydrocarbons. Seasonal means of size-grade fractions were not statistically different, although much inter- and intrastation variability occurred. Greater silt-clay content tended to occur at the head of the bay (especially in winter) and decreased down the bay. During fall and winter, the occurrence of silt-clay fractions tended to increase throughout the bay.

Extractable hydrocarbons exhibited significant seasonal differences (p < 0.05). Extractable hydrocarbon ranges were 1–1,273 μg/g dry sediment, with seasonal means of 160–327 μg/g dry sediment, depending on the bay region. Hydrocarbon content and percent volatiles generally increased with increased silt-clay content. Best correlations of hydrocarbons with silt-clay occurred in summer and fall. Throughout the seasons, hydrocarbon material appeared to move down the bay, with lowest values in fall-winter and the highest in spring-summer.
An In Situ assessment of the acute toxicity of urban runoff to benthic macroinvertebrates
Authors: Medeiros Carmen , Leblanc Ronald , Coler Robert A.
Published: March 2010

Colonized Hester-Dendy substrates were deployed for 96 h in an urban river reach, storm drain channel and a control site to assess the toxicity of urban runoff. The mean macroinver-tebrate diversity during rain events was reduced from 1.7 at the control station to 1.0 at both urban stations. Snowmelt exerted the same effect on river substrate diversity, but only reduced channel values from 2.0 to 1.4. During periods of no runoff, however, mean channel and control diversities remained the same (1.5), while river values dropped to 0.8. Similarly, substrate population densities during rain were, respectively, two and seven times more limiting for the storm drain channel and river reach stations. The same trend was evident in heavy metals uptake, indicating that dry weather toxicity in urban river reaches originates from the sediments. Runoff, then, serves to reduce toxicity during input, but increases it over the long run.
Patterns of toxicological effects in ecosystems: A modeling study
Authors: O'Neill R. V. , Bartell S. M. , Gardner R. H.
Published: March 2010

Differences in patterns of response in a pelagic ecosystem due to seasonal exposure and differential sensitivities of populations and trophic levels to chemical stress were examined with a simulation model. Simulations of constant 7-d exposures initiated at different times of year demonstrated that stresses imposed during the spring reduced average producer and consumer biomass. Stresses imposed later in the year reduced grazer biomass and permitted increased phytoplankton production. Simulated exposures to phenol, naphthalene and four heavy metals predicted different effects when toxic sensitivities of populations and trophic levels were ignored. Risks of increased blue-green algae production or decreased game fish production were estimated from repeated simulations that extrapolated uncertainties associated with individual toxic effects parameters. Estimates of risk that included population-specific toxicities were two or three times greater than risks estimated from trophic level toxicities alone.
A comprehensive prebiological screen for ecotoxicologic effects
Authors: Gillett James W.
Published: March 2010

Simple properties of chemicals—the octanol-water partition coefficient (Kow), Henry's Law constant (Hc) and biodegradability half-life (t1/2) — provide a means of evaluating ecotoxicologic testing requirements prior to direct screening using various organisms. Based on potential for exposure, arrays of properties portending ecotoxicologic concern are suggested for bioaccumulation and chronic effects, multispecies-multimedia involvement, inhalation toxicology and abiotic atmospheric effects.
Relative sensitivity ofChironomus tentanslife stages to copper
Authors: Nebeker Alan V. , Cairns Michael A. , Wise Claudia M.
Published: March 2010

The four larval instars of the midge Chironomus tentans Fabricius were exposed to copper to determine their relative sensitivities. The impact of copper on adult emergence and effect of exposure time on LC50 values were also determined. First-instar larvae appeared to be the most sensitive to acute exposure, with a 96-h LC50 of 298 μg/L copper, followed by second-instar (LC50 = 773 μg/L), third-instar (LC50 = 1,446 μg/L) and fourth-instar (LC50 = 1,690 μg/L) larvae, at a water hardness of 71 to 84 mg/L. Adults emerged successfully from fourth-instar larvae and pupae that survived 20-d copper exposures of up to 235 μg/L; the 20-day EC50 was 77.5 μg/L.

Methods for continuous culture of C. tentans in a flow-through rearing facility using Cerophyl, a commercially available powdered grass product, as food and substrate are presented.
Sampling and analytical procedures for evaluation of airborne chlordane levels in family quarters
Authors: Thomas Thomas C. , Nishioka Yoshimi A.
Published: March 2010

A sampling and analysis protocol was developed for determining trace levels of chlordane in the interior of family housing units. Chlordane, when applied as a termiticide through sub-slab injection, found its way into family quarters through heating ducts. In this study, methods were developed to sample and analyze for trace levels of this airborne chlordane. Commercially available Chromosorb 102 sampling tubes were evaluated and found to be extremely useful. Trace levels of chlordane collected on these commercial sampling tubes can be stored before analysis for up to 131 d after sampling, with no measurable loss of chlordane. Chlordane collection efficiency and recovery from Chromosorb 102 sampling tubes was found to be excellent.
Bioenergetic alterations correlated with growth, fecundity and body burden of cadmium for mysids (Mysidopsis bahia)
Authors: Carr Robert Scott , Williams John W. , Saksa Frank I. , Buhl Rosanna L. , Neff Jerry M.
Published: March 2010

Reduced growth and reproductive potential are common sublethal stress responses. Bioenergetic alterations as evidenced by scope for growth or O:N ratio measurements are also sensitive sublethal stress responses for certain animals. The O:N ratio, which is the ratio of oxygen consumed to nitrogen excreted in atomic equivalents, reflects the relative utilization of protein in energy metabolism. The purpose of the present study was to determine whether concentration-dependent alterations in the O:N ratio for mysids (Mysidopsis bahia) could be detected at various times during a life-cycle toxicity test and to assess the utility of this index for diagnosing bioenergetic responses that result in reduced growth and reproductive inhibition.

Juvenile M. bahia were exposed to cadmium (CdCl2) in a continuous-flow proportional diluter system. The exposure concentrations were monitored routinely throughout the test and varied less than ±10% from the nominal concentrations. The O:N ratio measurements were made at 4, 10 and 18 d of exposure. Dry weights and cadmium body burdens of individual mysids were made at day 18 and day 33, the termination of the test.

Significant alterations in the O:N ratio were evident by 4 d and indicated a shift toward lipid utilization with increasing cadmium concentration. Growth was significantly reduced in the lowest concentration (4 ppb) at 18 d and a linear concentration-dependent increase in the cadmium body burden was observed at the termination of the test. These results suggest that alterations in the O:N ratio are a sensitive and early diagnostic index for detecting sublethal stress responses. We feel that this approach could be used in place of the standard life-cycle toxicity test for determining the concentration of a toxicant at which no effect on growth and reproductive processes will occur.
Computation of total molecular surface area from gas phase ion mobility data and its correlation with aqueous solubilities of hydrocarbons
Authors: Lande S. S. , Hagen D. F. , Seaver A. E.
Published: March 2010

Gas phase ion mobility data of molecular ions were utilized to estimate the total molecular surface area (TSA) of neutral molecules. Assumptions are made in the first approximation that ions/molecules can be represented as equivalent hard spheres and that the radii of the neutral molecule and its gas phase molecular ion are equal. TSA values derived from experimental ion mobilities measured by plasma chromatography compared reasonably (±5%) with TSA data derived from computer-simulated molecular models for the polynuclear aromatic hydrocarbons, butylbenzene isomers and linear alkanes. The known relationship between logarithms of aqueous solubility and TSA for the solute was examined utilizing TSA values derived from ion mobility data. Correlation coefficients exceeded 0.95 for aromatic hydrocarbons and for linear alkanes of fewer than 12 carbons but not for longer alkane chains.