bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal toxicity in two rodent species and redox potential: Evaluation of quantitative structure—activity relationships
Authors: Lewis, David FV , Dobrota Miloslav , Taylor Marina G , Parke Dennis V
Published: March 2010

A quantitative structure—activity relationship study of acute toxicity in the mouse and rat is described for the soluble salts of a relatively large number of metals (between 25 and 30 in total). Electrode potential is the major determinant of acute metal toxicity (R = 0.85 and 0.86) for an intraperitoneal dose in the mouse, whereas the addition of ionic radius and polarizability enables the inclusion of notable outliers in the original expression, such as beryllium and barium, thus giving a good correlation (R = 0.87) with toxicity for 27 metal compounds. These findings are rationalized on the basis of relative ease of ionization, electron affinity, and transport factors of the metals and their ions, thus being consistent with the hard and soft acids and bases properties of metals and their biological reactivities.
Decolorization of olive oil mill wastewaters by Phanerochaete flavido-alba
Authors: Hamman Omar Ben , de la Rubia Teresa , Martínez José
Published: March 2010

Olive oil mill wastewater (OMW), a major waste product of olive oil extraction, contains many recalcitrant compounds, mainly present in the colored fraction. In this study we attempted to identify optimum culture conditions for the decolorization of OMW by Phanerochaete flavido-alba for subsequent use in bioremediation assays. Of several media tested, nitrogen-limited P. flavido-alba cultures containing 40 mg/L Mn(II) were the most efficient at decolorizing OMW. Decolorization was accompanied by a 90% decrease in the OMW phenolic content. Concentrated extracellular fluids alone (showing manganese peroxidase, but not lignin peroxidase activity) did not decolorize the major OMW pigment, suggesting that mycelium binding forms part of the decolorization process.
Relative sensitivity of marine species to an effluent with elevated total dissolved solids
Authors: Kline Edward R , Stekoll Michael S
Published: March 2010

The acute toxicity of aged gold mill effluent was compared for two reference species (juvenile mysid shrimp [Mysidopsis bahia (Americamysis bahia)] and larval sheepshead minnows [Cyprinodon variegatus]) and larvae of three species that are indigenous to the southern coast of Alaska (red king crab [Paralithodes camtschaticus], northern shrimp [Pandalus borealis], and Pacific herring [Clupea harengus pallasi]). Effluent osmolality was equivalent to that of 12 ppt seawater. Concentration–response relationships for the effluent, adjusted to equal the osmolality and pH of 31 ppt seawater, were determined after 24 h of exposure for immobility, paralysis, and death. The magnitude of differences and rank of sensitivity of the indigenous species depended on the response that was used for the comparison. For all responses, M. bahia and C. variegatus were the most and least sensitive species, respectively.
Comparative toxicity and toxicokinetics of ddt and its major metabolites in freshwater amphipods
Authors: Lotufo Guilherme R , Landrum Peter F , Gedeon Michelle L , Tigue Elizabeth A , Herche Lynn R
Published: March 2010

The toxicity and toxicokinetics of radiolabeled DDT and its major degradation products, dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE), were determined for the amphipods Hyalella azteca and Diporeia spp. in water-only static renewal exposures. Comparison of the water and tissue concentrations associated with decreased survival revealed large differences in toxicity among the three compounds. In H. azteca, the ratio of the 10-d LR50 values (median lethal tissue residue) for DDT:DDD:DDE was 1:24:195. In Diporeia spp., the 28-d LR50 for DDT was higher than that for DDD by a factor of six, and DDE did not cause significant mortality even at concentrations approaching the solubility limit. Based on the toxicity data, the hazard from exposure to mixtures of DDT and its degradation products should be evaluated on a toxic-units basis and not as a simple summation of the individual concentrations, which ignores the toxicity of specific compounds. Differences in species sensitivity were also detected. The 10-d LR50 values were higher in Diporeia spp. than in H. azteca by a factor of 40 for DDT and eight for DDD. This difference can be only partly attributed to differences in lipid content between H. azteca (7% dry wt) and Diporeia spp. (24% dry wt). The uptake clearance and elimination rate constants were similar among the various compounds in both species. Uptake clearance was typically fourfold greater for H. azteca than for Diporeia spp., however, and the experimentally measured elimination rate was approximately 30-fold greater in H. azteca than in Diporeia spp. The larger rates of uptake and elimination were attributed to the higher exposure temperature, greater surface area-to-volume ratio, and lower lipid content for H. azteca compared with Diporeia spp. In addition, extensive biotransformation of DDT by H. azteca may have contributed to a more rapid compound elimination.
Bioaccumulation patterns of polychlorinated biphenyls and chlorinated pesticides in Northwest Atlantic pilot whales
Authors: Weisbrod Anne V. , Shea Damian , Moore Michael J , Stegeman John J
Published: March 2010

Contaminant exposure is widespread among marine mammals but is of unknown significance. This study characterized organochlorine bioaccumulation in pilot whales, and these bioaccumulation patterns are proposed as representative of Northwest (NW) Atlantic cetacea. Samples were collected from whales stranded in Massachusetts and caught in nets. Polychlorinated biphenyl (PCB) and chlorinated pesticide concentrations were determined via GC/ECD and found to be similar to those reported for other NW Atlantic odontocetes. The organochlorine in highest concentration was 4,4′-DDE, followed by trans-nonachlor, 4,4′-DDD, dieldrin, cis-chlordane, Cl4(52), Cl5(95), Cl5(101), Cl5(118), Cl6(138), Cl6(149), Cl6(153), Cl7(180), and Cl7(187). The concentration of 19 pesticides was higher in blubber (21 ± 26 μg/g lipid “ppm”) than liver (5.0 ± 7.1 ppm). The concentration of 26 PCB congeners was also greater in blubber (7.6 ±7.1 ppm) than liver (0.4 ± 7.3 ppm). Principal component analysis and ANOVA indicated that blubber accumulated proportionately more of the most recalcitrant compounds, such as 4,4′-DDE and nonmetabolizable PCBs, compared to liver. Whales that stranded together had more similar bioaccumulation than animals of the same gender or maturity. The high variation among individuals in tissue concentrations and the similarity within a stranding group suggest that pilot whale pods are exposed to a large range of pollutant sources, such as through different prey and feeding locations.
Community-level responses by stream insects to neem products containing azadirachtin
Authors: Kreutzweiser David P , Capell Scott S , Scarr Taylor A
Published: March 2010

Outdoors sream channels weret teated with a commercial neem formulation, Neemixx® 4.5, and a neem extract (no formulation ingredients) to determine the effects on aquatic insect communities. An exposure period of 5 h was chosen to simulate the transient nature of pesticide residues in streams and rivers after aerial applications. Multivariate analytic procedures based on Bray-Curtis similarity matrices were used to compare community structure among the replicate channels 9 d after treatment. No significant differences in community structure were found among controls and channels treated with Neemix at an azadirachtin concentration of 0.28 mg/L, but a multivariate measure of community stress indicated an increase in variability among treated channels. Significant differences in community structure were found among controls and channels treated with Neemix at 0.84 and 2.54 mg/L, and this resulted from reductions in several key taxa. During subsequent experiments with a neem powder extract, the formulation ingredients of Neemix were at least partially responsible for the significant effects on community structure at 0.84 mg/L azadirachtin. No significant differences were found among controls and channels treated with the extract at 0.9 mg/L, whereas the community structure of aquatic insects in channels treated at 3.0 mg/L differed significantly from controls. In a Canadian forest pest-management context, the expected environmental concentration in water bodies of areas sprayed with azadirachtin at 50 g/ha is 0.035 mg/L.
Whole-lake burdens and spatial distribution of cadmium in sediments of Wisconsin seepage lakes, USA
Authors: Powell David E. , Rada Ronald G , Wiener James G , Atchison Gary J
Published: March 2010

Cadmium was quantified in the surface sediments of six seepage lakes ranging from 8 to 70 ha in surface area, 6 to 20 m in maximum depth, 5.2 to 7.0 in mean epilimnetic pH, and 1.7 to 6.8 mg·L−1 in dissolved organic carbon. Within each lake, dry-weight concentrations of cadmium (range, 0.02–7.17 μg·g−1) were positively correlated with volatile matter content of the sediments, which increased with water depth. Volumetric concentrations (i.e., mass per volume of wet sediment) were correlated with water depth in only one lake, and they more accurately represented the spatial distribution of sedimentary cadmium within the lakes. Analysis of sediment cores from two of the lakes indicated that surface sediments were enriched with cadmium. The source of cadmium and the within-lake processes controlling deposition to the sediments were presumably similar among the lakes, as demonstrated by the strong correlation between lake area and whole-lake burdens of cadmium in the surface sediments (range, 625–5785 g/lake). Hence, cadmium in these lakes appears to be derived largely from atmospheric deposition. When normalized for lake area, cadmium burdens in the surface sediments ranged from 62 to 92 g·ha−1 and were strongly correlated with dissolved organic carbon, but not with lake pH, which suggests a link between the transport of cadmium and organic matter to the sediments.
Acute toxicity of storm water associated with de-icing/anti-icing activities at Canadian airports
Authors: Novak Lesley J , Holtze Keith , Kent Robert A , Jefferson Catherine , Anderson Don
Published: March 2010

Environment Canada, Transport Canada, and the Airline Transport Association of Canada recently evaluated the use of toxicity bioassays to assist in managing wastewater from aircraft de-icing at Canadian airports. This study evaluated the effectiveness of a suite of rapid screening bioassays to predict the responses of standard regulatory test organisms to storm water associated with de-icing at four Canadian airports. Storm water samples were tested using two standard acute lethality bioassays (rainbow trout [Oncorhynchus mykiss], Daphnia magna) and four rapid screening bioassays (Daphnia IQ™, acute Microtox®, Rotoxkit®, Thamnotoxkit®). Environmental samples (runoff water) and concentrated de-icing/anti-icing chemicals from the clean-up vehicles (sweeper trucks) were collected from each airport and tested. Forty percent (n = 10) of the environmental samples were lethal to trout, and 30% were lethal to D. magna. The IQ and Thamnotoxkit test results were comparable to those of the trout and daphnid bioassays, respectively. Disadvantages associated with the IQ and Thamnotoxkit bioassays included the lack of a standardized quality-assurance/quality-control program, subjectivity in endpoint measurements, and problems in cyst hatching. The limited number of storm-related samples did not permit definitive determination for the causality of toxicity. Results suggest that glycol was not predictive of acute lethality, and that other substances likely contributed to toxicity.
Effects of endocrine-active chemicals on the development of sex characteristics of Daphnia magna
Authors: Olmstead Allen W , LeBlanc Gerald A
Published: March 2010

Standard reproductive assays with daphnids involve parthenogenetically reproducing females and exclude the assessment of effects on sexual reproduction. The goals of this study were to characterize sexual differentiation of male and female daphnids (Daphnia magna) and to evaluate whether exposure to putative endocrine-disrupting chemicals may perturb the development of sex characteristics. Anatomical sex differences that developed during maturation in males included elongated first antennae and morphologic alterations in the head capsule and carapace edge. Reproductive maturation in females was associated with the development of a brood chamber and abdominal process. Alterations in the growth rates of the first antennae of males and the abdominal process of females were used to evaluate the effects of chemical exposure on the development of these sex characteristics during maturation. Exposure of female daphnids to the nonsteroidal vertebrate estrogen diethylstilbesterol and the insect juvenile hormone analog methoprene at concentrations as low as 3.0 and 0.080 μM, respectively, stimulated development of the abdominal process. Exposure of males to the steroidal vertebrate androgen androstenedione (≥6.0 μM) stimulated development of the first antennae. These results demonstrate that the development of secondary sex characteristics in daphnids can be altered by chemical exposure.
Test of Σ polycyclic aromatic hydrocarbon model at a creosote-contaminated site, Elliott Bay, Washington, USA
Authors: Ozretich Robert J , Ferraro Steven P , Lamberson Janet O , Cole Faith A
Published: March 2010

At a creosote-contaminated site, 33 individual polycyclic aromatic hydrocarbon (PAH) compounds were quantified in sediment and interstitial water (IW) at 30 stations. These compounds included the 13 parent PAHs from the ΣPAH model, 7 additional parent, and 13 alkylated compounds. Fourteen groups of alkylated compounds were also quantified in sediment extracts. Amphipod mortality using the ΣPAH model was predicted within ±10% of the observed when freely dissolved concentrations of PAHs with log Kows < 6.0 were used in the calculation of toxic units (TUs). The TUs computed from bulk sediment tended to overestimate the observed distribution of mortality. Although present, alkylated PAHs did not contribute significantly to the observed toxicity that was dominated by parent PAHs. The dominant parent compounds were in equilibrium with the interstitial water and sediment at the most contaminated stations (>500 ppm dry). However, most compounds were not in equilibrium with the sediment at stations with lower bulk concentrations but were in equilibrium with dissolved organic matter throughout the study area.
In vitro and in vivo association of 2,3,7,8-tetrachlorodibenzo-p-dioxin and benzo[a]pyrene with the yolk-precursor protein vitellogenin
Authors: Monteverdi George H , Giulio Richard T. Di
Published: March 2010

These studies investigated the association ofcommon environmental contaminants 2,3,7,8-tetraclorodibenzo- p-dioxin (TCDD) and benzo[a]pyrene (B[a]P) with the yolk-precursor protein vitellogenin (VTG). In vitro studies with purified VTG from the channel catfish (Ictaluruspunctatus) demonstrated that 3H-TCDD and 3H- B[a]P associated with VTG in a nonsaturable manner. The magnitude of this association (i.e., pmoles of radioligand/mg VTG) increased with increasing chemical concentrations until the point of chemical insolubility in the incubation medium. In vivo, time-course experiments with gravid female mummichogs (Fundulus heteroclitus) exposed to either 3H-TCDD or 14C-B[a]P revealed time- and dose-dependent changes in total serum radiochemical content. In sera from female F. heteroclitus exposed to either chemical, >80%of detected radioactivity was associated with VTG and a second chromatographic peak, a lipoprotein fraction putatively identified as high-density lipoproteins. In experiments comparing radiochemical serum compartmentalization in estrogenized (E2+) versus control male fish, the presence of VTG in E2 + males significantly altered the overall quantity and profile of serum protein-associated radiochemical. In these experiments, serum VTG was present in very large quantities (40-50% of total serum protein) and the majority (62-81% for 3H-TCDD; 56-71% for 14C-B[a]P) of radiolabeled ligand was associated with VTG. The structure of the VTG protein, combined with the apparently nonsaturable nature of the association between VTG and these lipophilic compounds, suggests a VTG-ligand association that is both nonspecific and of significant capacity. Given the central role of VTG in egg production and early-life development, these findings suggest a significant role for VTG as a vector of xenobiotic maternal transfer. This role is further supported by companion studies (this volume) that examined oocyte accumulation of TCDD and B[a]P.
Dose-dependent growth inhibition and bioaccumulation of hexavalent chromium in land snail Helix aspersa aspersa
Authors: Cœurdassier Michaël , Vaufleury Annette Gomotde , Badot Pierre-Marie
Published: March 2010

The toxicity of Cr6+ was determined in a laboratory environment in the snail Helix aspersa aspersa. The effects on growth were evaluated on animals reared in controlled conditions at the age of one month that had been exposed for 28 d to increasing doses of Cr6+ mixed in with their food. Two experimental groups were set up with concentrations of chromium in the feed of 250 to 1,250 μg/g (test 1) and 100 to 800 μg/g (test 2). Growth inhibition was dose dependent, and the mean EC50 calculated at four weeks for tests 1 and 2 were, respectively, 354.7 and 298.8 μg/g and for the EC10 195.3 and 160.9 μg/g. The levels of Cr6+ bioaccumulated in the foot and the viscera of the snails were dose dependent in both types of tissues. The highest concentrations occurred in the viscera, the levels being 0.79 μg/g in the controls and reaching 3,067 μg/g in the animals exposed to the maximum contamination (1,250 μg/g). These high levels of bioaccumulation in addition to the lower concentrations of Cr6+ excreted in the feces than those present in the food suggest that chromium is not physiologically regulated by Helix aspersa. The results provide added support for the use of snails as a model to determine the toxicity of substances in laboratory biotests by measuring the effects on growth and by assessing bioaccumulation.
Analysis of some factors that may modify the bioavailability of cadmium and lead by Biomphalaria glabrata
Authors: Guerrero Noemí R Verrengia , Nahabedian Daniel E , Wider Eva A
Published: March 2010

Laboratory acute bioassays (t = 96 h) were used to determine the uptake, distribution, and elimination of cadmium and lead by the freshwater gastropod Biomphalaria glabrata. Experiments were conducted on nonpigmented and pigmented organisms separately. The influence of food and different concentrations of humic acids were also investigated. The results showed that, after the treatments, the digestive gland presented the highest level of metal uptake for both elements. Food did not prove to induce significant changes in the pattern of accumulation and distribution within the different tissues. Instead, different concentrations of humic materials modified the pattern of accumulation and distribution of cadmium and lead but in a different way according to the metal. Elimination of cadmium from the soft tissues was considerably slow, presenting a redistribution over the time of depuration. Elimination of lead was faster in the digestive gland and gonads. After all the treatments, no significant differences were observed between nonpigmented and pigmented snails.
Interspecies differences in oxidative stress response and radiocesium concentrations in rodents inhabiting areas highly contaminated by the chornobyl nuclear disaster
Authors: Holloman Kevin A , Dallas Cham E , Jagoe Charles H , Tackett Randall , Kind John A , Rollor Edward A
Published: March 2010

Indicators of oxidative stress response were compared to radionuclide concentrations in rodents from highly contaminated sites around the Chornobyl Nuclear Power Plant, Ukraine, and uncontaminated reference areas. Three rodent species—Apodemus agrarius, Apodemus sylvaticus1, and Clethrionomys glareolus (n = 121)—wecollected from contaminated sites within the 10km exclusion zone surrounding the Chornobyl Nuclear Power Plant and from uncontaminated reference areas in northern Ukraine. Liver samples were analyzed for superoxide dismutase (SOD) and catalase (CAT) activities, and muscle samples were analyzed for radiocesium activity. Superoxide dismutase and catalase activities differed significantly between reference and contaminated groups only for A. agrarius, and activities were lower in contaminated animals relative to those from reference sites. The SOD activity did not differ among species collected in reference areas. Among contaminated groups, A. agrarius had a significantly lower SOD activity than the other two species. Among reference groups, CAT activity for C. glareolus was significantly lower than for the other two species. Very high muscle radiocesium activities (up to 60,000 Bq/g) were found in rodents from contaminated areas, while the references for each species were at or below background. Clethrionomys glareolus had significantly higher muscle radiocesium concentrations than the other species collected at contaminated sites. There were no significant correlations between either SOD or CAT activities and muscle radiocesium concentrations for contaminated or reference animals in any species. There are significant interspecies differences in oxidative enzyme activities in rodents with lifetime exposure at highly radioactive contaminated sites. However, internal radiocesium concentration is not a sensitive predictor of these oxidative stress responses in individuals.
Fate and kinetics of carfentrazone-ethyl herbicide in California, USA, flooded rice fields
Authors: Ngim Kenley K , Crosby Donald G
Published: March 2010

Little is known of the environmental fate of the aryltriazolinone herbicide carfentrazone-ethyl (compound I). Rice field applications of Shark® 40D commercial formulation to duplicate 5.7 m2 rings (119 g a.i./ha) and 464 m2 commercial basins (224 g a.i./ha) produced pseudo–first-order half-lives (t½) of 6.5 to 11.1 h in water and 37.9 to 174 h in sediment. The rapid dissipation from water was due to its hydrolysis to the chloropropionic acid (compound II), which further degraded to its propionic, cinnamic, and benzoic acids. Compound I degraded similarly in soil, but propionic and cinnamic acid levels were higher. Compound I was only weakly adsorbed, but lateral movement of compound II through soil occurred. Laboratory hydrolysis produced quantitative yields of compound II, t½ values of 131 h at pH 7 and 3.36 h at pH 9, and slow dissipation at pH 5 (43% at 830 h). Ultraviolet (UV) irradiation of compound I in pH 7 buffer gave dissipation rates similar to those in dark controls (t½ 113 h vs 128 h), while compound II was comparatively stable to photolysis (t½ 765 h) and also did not volatilize from water. Ester hydrolysis followed by off-site movement of the acid (compound II) account for the dissipation of compound I.
Estimation of water solubility from atom-type electrotopological state indices
Authors: Huuskonen Jarmo
Published: March 2010

Based on the atom-typee ectrotopological state (E-state) indices, a quantitative structure–property relationship model for the prediction of aqueous solubility for a diverse set of 745 organic compounds is presented. The multiple linear regression analysis was used to build the models. A training set of 674 compounds, containing 349 liquids and 325 solids and having a range of aqueous solubility (log S) values from 2.77 to —11.62, was obtained from the literature. For this set, the squared correlation coefficient and standard deviation for a linear model with 31 atom-type E-state indices and three simple correction factors were r2 = 0.94 and s = 0.58 (log units), respectively. The corresponding statistics for the test sets not included in the training set were, for a set of 50 pesticides, r2 = 0.79 and s = 0.81 and, for a set of 21 drug and pesticide compounds, r2 = 0.83 and s = 0.84, respectively. The contribution of melting points was also evaluated. The use of melting point increased the accuracy of the models in the fit of the training set but not in the prediction of the test sets. Hence, the proposed method offers fast and accurate estimation of aqueous solubility of organic compounds using atom-type E-state indices without the need of any experimental parameters like the melting points.
Theoretical framework for the distribution of trace metals among the operationally defined speciation phases of a sediment
Authors: Nome René A. , Mendiguchía-Martínez Carolina , Nome Faruk , Fiedler Haidi D
Published: March 2010

The use of a model based on Langmuir's isotherm to evaluate the metal associated with separate geochemical phases of a sediment is proposed and its validity tested with sediments of certified composition. The model takes into account a standard procedure for a certified reference material (CRM601), which defines, experimentally, a set of sequential extractions that divide the sediment into four operational fractions. The derived equations allow the treatment of data from sediment of Flumendosa Lake, Italy, and certified material CRM601 and also allow the computation of corrected concentrations, i.e., the metal affinities for each fraction. Experimental values for Ni show its low sensitivity and an equal distribution among different phases, which suggests a similar adsorption mechanism in all cases. In the case of Cd, the corrected concentration in the Fe/Mn oxide phase is nine times higher than for the residual fraction. For sediment of the Bèsos River, Spain, results show the percentage distribution of Ni over different fractions. Affinity values for Ni on a Flumendosa Lake sediment have also been calculated. The present model is simple to apply and shows satisfactory agreement with experimental data.
Bioaccumulation of polycyclic aromatic compounds: 1. Bioconcentration in two marine species and in semipermeable membrane devices during chronic exposure to dispersed crude oil
Authors: Baussant Thierry , Sanni Steinar , Jonsson Grete , Skadsheim Arnfinn , Børseth Jan Fredrik
Published: March 2010

Assessing the fate in marine biota of hydrocarbons derived from oil particles that are discharged during exploration and production is of relevant environmental concern. However, a rather complex experimental setup is required to carry out such investigations. In this study, a sophisticated tool, the continuous-flow system (CFS), was used to mimic dispersed oil exposure to marine biota. Polycyclic aromatic hydrocarbon (PAH) uptake was studied in two species, the blue mussel Mytilus edulis and juvenile of the turbot Scophthalmus maximus, and in semipermeable membrane devices (SPMD) exposed to crude oil dispersed in a flow-through system. After an exposure period of 8 to 21 d, elimination in organisms and devices was analyzed for 9 to 10 d following transfer to PAH-free seawater. Principal component analysis (PCA) revealed different PAH patterns. In mussel and SPMD, the PAH profiles were very close to that analyzed in seawater. Slight differences were, however, indicated for large molecules with log Kow above six. Nonachievement of steady-state concentration and bioavailability of PAH in oil droplets may account for these differences. The PAH composition in fish revealed only congeners with two to three aromatic rings. A combination of bioavailability and efficient metabolism of the larger PAH molecules may explain this pattern. The CFS made possible a better understanding of some critical factors governing bioconcentration in marine biota from dispersed oil. Yet the results illustrate that uptake of PAH from exposure to oil particles is complex and that different species may bioconcentrate different molecules depending on factors like life style and metabolic capability to degrade the potential harmful substances. Hence, risk assessment of the actual impact of discharges to marine biota should consider these essential biological and ecological factors.
Loss rates of polycyclic aromatic hydrocarbons from sediment and deposit-feeder fecal pellets
Authors: Horng Ching-Yi , Taghon Gary L
Published: March 2010

Deposit feeders modify sediment by aggregating individual particles into fecal pellets. Loss of contaminants may be either more (enhanced bacterial degradation) or less (hindered diffusion and desorption) rapid for sediment incorporated into pellets. We studied the loss of 10 polycyclic aromatic hydrocarbons (PAHs) from historically contaminated estuarine sediment and the same sediment after it had been pelletized by Capitella sp. I, a polychaete worm typically found in disturbed environments. Fecal pellets initially had higher concentrations of organic carbon and PAHs (enrichment factors 1.03–1.21) due to selective feeding. Over 60 d, desorption of PAHs was minimal, with an average loss of 4 to 5%. Biodegradation accounted for an additional 28% loss. A two-component model fit the data well and indicated that the slowly desorbing fraction was close to one for all PAHs. For low molecular weight PAHs, biodegradation rate constants were greater than desorption rate constants; for high molecular weight PAHs, the opposite was found. Desorption rate constants were similar for fecal pellets (0.0002–0.037/d) and sediment (0.0002–0.031/d). Biodegradation rate constants were also similar for fecal pellets (0.0006–0.022/d) and sediment (0.0002–0.018/d). Thus, incorporation of sediment into robust fecal pellets (half-life on the order of decades) did not affect the loss rates of PAHs.
Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 2. Toxicity of aircraft and runway deicers
Authors: Corsi Steven R , Hall David W , Geis Steven W
Published: March 2010

Streams receiving runoff from General Mitchell International Airport (GMIA), Milwaukee, Wisconsin, USA, were studied to assess toxic impacts of aircraft and runway deicers. Elevated levels of constituents related to deicing (propylene glycol, ethylene glycol, and ammonia) were observed in stream samples. The LC50s of type I deicer for Ceriodaphnia dubia, Pimephelas promelas, Hyalela azteca, and Chironimus tentans and the EC50 for Microtox® were less than 5,000 mg/L of propylene glycol. Concentrations up to 39,000 mg/L were observed at airport outfall sites in samples collected during deicing events. The IC25s of type I deicer for C. dubia and P. promelas were less than 1,500 mg/L of propylene glycol. Concentrations up to 960 mg/L were observed in low-flow samples at an airport outfall site. Measured toxicity of stream water was greatest during winter storms when deicers were applied. Chronic toxicity was observed at airport outfall samples from low-flow periods in the winter and the summer, with the greater toxic impacts from the winter sample. All forms of toxicity in stream-water samples decreased as downstream flows increased.
The effect of thiolate organic compounds on methylmercury accumulation and redistribution in sheepshead minnows, Cyprinodon variegatus
Authors: Leaner Joy Jacqueline , Mason Robert Peter
Published: March 2010

Methylmercury (CH3Hg(II)) was measured in various tissues and whole body of sheepshead minnows, Cyprinodon variegatus, following exposure to 100 ng/L methylmercury chloride (CH3HgCl) alone or in combination with one of the organic compounds cysteine (CH3Hg-Cys), thiourea (CH3Hg-Thu), or thioglycolate (CH3Hg-Thg). Overall, the CH3Hg(II) concentration in sheepshead minnows in all the treatments increased with time and was significantly different from the unspiked controls after 24 h. Addition of the organic compounds increased the bioavailability of CH3Hg(II) in the whole body of the fish after 72 h. In particular, the CH3Hg(II) concentration after CH3Hg-Thg and CH3Hg-Thu exposure was, respectively, approximately 1.3- and 1.6- fold higher than with CH3HgCl exposure. A composite of the CH3Hg(II) concentrations in the visceral organs (gill, liver, and intestine) highlighted the effect of the organic compounds, where concentrations in all mercury-thiolate treatments were significantly higher than CH3HgCl alone after 72 h. The most dramatic changes in the different tissues measured were observed in the liver, where the CH3Hg(II) concentrations in the sulfur treatments were significantly higher than the CH3HgCl treatment after 72 h. The results of this study suggest that the CH3Hg-thiolate complexes were bioavailable to sheepshead minnows and effectively induced CH3Hg(II) uptake in tissues at environmentally realistic CH3HgCl concentrations.
Behavioral effects of ivermectin in a freshwater oligochaete, Lumbriculus variegatus
Authors: Ding Jing , Drewes Charles D , Hsu Walter H.
Published: March 2010

Ivermectin is a potent antiparasitic drug against nematode and arthropod parasites. In this study, we examined the lethal and sublethal effects of ivermectin in a freshwater oligochaete, Lumbriculus variegatus. The median lethal concentration (LC50) at 72 h after ivermectin exposure was 560 nM. Sublethal endpoints focused on several stimulus-evoked locomotor behaviors: escape reflexes controlled by giant interneuron pathways, swimming and reversal, and crawling. Swimming, reversal, and crawling are controlled by nongiant interneuron pathways. Ivermectin inhibited swimming, reversal, crawling frequency, and crawling speed in a time- and concentration-dependent manner with a mean inhibitory concentration (IC50) at 3 h of 1.1, 16, 91, and 51nM, respectively. Ivermectin at 0.3 nM also significantly decreased the frequency of helical swimming waves. Picrotoxin, a Cl− channel blocker, antagonized the ivermectin-induced decrease in swimming frequency, crawling frequency, and crawling speed. There were no adverse effects on escape reflex 3 h after exposure to 300 nM ivermectin. Electrophysiological recordings showed that ivermectin had no effects on the conduction velocity of giant fiber systems. The results indicated that locomotor behaviors controlled by nongiant locomotor pathways were more sensitive to ivermectin than pathways controlled by giant interneurons and that Cl− channels may be involved in mediating ivermectin's inhibitory effects.
Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 4. The influence of salt speciation, soil type, and sewage sludge on toxicity using the collembolanFolsomia fimetariaand the earthwormAporrectodea caliginosaas test organisms
Authors: Holmstrup Martin , Krogh Paul Henning , Løkke Hans , de Wolf Watze , Marshall Stuart , Fox Kay
Published: March 2010

Sewage sludge applied to agricultural soils often contains linear alkylbenzene sulfonates (LAS) in the range of 1 to 10 g/kg dry weight, and their toxicity to relevant soil organisms should, therefore, be assessed to ensure safe use of sewage sludge as a fertilizer. Studies of LAS toxicity to soil organisms are few, and to our knowledge, factors that may influence the toxicity in the field have not been studied in detail. In this paper, we report on the influence of speciation of LAS in the test solution added to soil (soluble Na-LAS vs poorly soluble Ca-LAS or Mg-LAS), the influence of soil type, and the modifying effects of sludge amendment on the toxicity of LAS. These issues were investigated using reproduction of Collembola and growth of juvenile earthworms as test parameters. Speciation of the LAS added to test soil did not have any influence on toxicity for any of the test species. Likewise, in three different agricultural soils (sand, loam, and clay), we found almost equal toxicities. The LAS added to test soil in a sludge—water suspension was equally toxic as when it was added in an aqueous solution. However, anaerobic incubation for 7 and 14 d of the LAS—sludge suspension (with no decay of LAS) caused the toxicity to increase almost threefold in both collembolan and earthworm. The relationships between soil constituents, bioavailability, and toxicity are also discussed.
Kinetics, dose-response, excretion, and toxicity of methylmercury in free-living Cory's shearwater chicks
Authors: Monteiro Luis R , Furness Robert W
Published: March 2010

Methylmercury (MHg) kinetics, dose–response, excretion, and toxicity were experimentally evaluated and compared between small (one to two weeks old) and large (six to seven weeks old), free-living Cory's shearwater chicks. The half-time for the terminal elimination phase of MHg in blood (5.7 d) and the average percentage of ingested MHg deposited in the blood volume (12%) were independent of the age at exposure. Therefore, these data were employed to derive a relationship between steady-state blood concentrations and dietary intake of MHg in bird chicks. Plumage:blood ratios were independent of dose and could be used as partition coefficients. Dose–response relationships in plumage and blood were linear over the wide range of exposures employed. Blood dose–responses of MHg in small and large chicks were similar. Excretion percentages into the final plumage varied between 42 and 60% of intake. The body condition of experimental chicks did not indicate sublethal toxicity of the doses administered; hence, the exposure levels provide maximum avian no-observed-adverse-effect levels for external symptoms in wild seabird chicks.
Identification and quantitation method for nonylphenol and lower oligomer nonylphenol ethoxylates in fish tissues
Authors: Snyder Shane A , Keith Timothy L , Naylor Carter G , Staples Charles A , Giesy John P
Published: March 2010

Substantial research is currently focused on the toxicological effects of alkylphenol ethoxylates (APEs) and alkylphenols (APs) on aquatic animals. Considerable data are available on the concentrations of APEs and APs in river systems in the United States; however, few if any data are available on the tissue concentrations of fish living in these rivers. A reliable method for the analysis of nonylphenol (NP) and lower oligomer nonylphenol ethoxylates (NPE1–3) in fish tissues has been developed. Nonylphenol and NPE1–3 were extracted from fish tissues using extractive steam distillation. Normal phase high-performance liquid chromatography (HLPC) was used as a cleanup step prior to analysis by gas chromatography with mass selective detection (GC/MSD) using selected ion monitoring. Optimization of this technique resulted in consistent recoveries in excess of 70%, with the exception of NPE3 (17%). Method detection limits (MDLs) and limits of quantitation using the technique range from 3 to 20 and 5 to 29 ng/g wet weight, respectively. Nonylphenol and NPE1 were detected in subsamples (n = 6) of a single common carp captured in the Las Vegas Bay of Lake Mead (NV, USA) at average concentrations of 184 ± 4 ng/g and 242 ± 9 wet weight, respectively. Nonylphenol ethoxylates2&3 were not detected in the carp collected at Lake Mead.
Identification of hydroxylamino-dinitroso-1,3,5-triazine as a transient intermediate formed during the anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine
Authors: Adrian Neal R , Chow Teresa
Published: March 2010

The metabolic fate of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a mixed culture incubated under methanogenic conditions was studied. Analysis by high-performance liquid chromatography (HPLC) confirmed the loss of RDX and the formation of mono-, di-, and trinitroso-RDX as transient biodegradation intermediates. An additional peak observed in the HPLC chromatograms was identified by liquid chromatography–mass spectrometry as hydroxylamino-dinitroso-1,3,5-triazine. This is the firstreport identifying hydroxylamino-dinitroso-1,3,5-triazine as a transient intermediate produced during the anaerobic biodegradation of RDX.
Effects of terbutryn on aufwuchs and Lumbriculus variegatus in artificial indoor streams
Authors: Brust Kristin , Licht Oliver , Hultsch Veit , Jungmann Dirk , Nagel Roland
Published: March 2010

The effects of the herbicide terbutryn on a simple lotic food web were investigated during a 72-d exposure period in five artificial indoor streams in a greenhouse. The model compound terbutryn, an s-triazine and an inhibitor of photosynthesis, was applied once in each stream at nominal concentrations of 0.6, 6, 60, or 600 μg/L. Terbutryn concentrations in the water were analyzed by gas chromatography/mass spectrometry, and an overall time to 50% dissipation (DT50) of 28 d was calculated. The development of aufwuchs and the population growth and development of the oligochaete Lumbriculus variegatus were investigated. We determined that terbutryn was toxic to L. variegatus at 23.7 mg/L (96-h median lethal concentration [LC50]) and 16.5 mg/L (96-h median effective concentration [EC50]) in static acute toxicity tests. Terbutryn decreased aufwuchs production at 0.6 μg/L in the experimental streams. Population growth of L. variegatus was decreased by 50% at 6 μg/L. The effect of terbutryn on the aufwuchs was a direct effect of decreases in the periphyton. However, the effects on L. variegatus were an indirect effect of terbutryn as a consequence of decrease in the aufwuchs food source and occurred at three-orders-of-magnitude-lower concentrations of terbutryn than the acute toxicity effects. Our study demonstrates the utility of indoor lotic microcosm studies for evaluating both direct and indirect effects of contaminants on aquatic ecosystems.
Air-water partition constants for volatile methyl siloxanes
Authors: Kochetkov Alexander , Smith Jeffrey S , Ravikrishna Raghunathan , Valsaraj Kalliat T , Thibodeaux Louis J
Published: March 2010

Silicones are an important class of hydrophobic compounds in widespread use. To evaluate their fate in the environment, an accurate value of the air-water partition (Henry's law) constant is necessary, which, unfortunately, is lacking at present. A static head space and a newly developed dynamic vapor entry loop method were used to obtain the air-water partition constant for six volatile methyl siloxanes. Internally consistent data were obtained. The value of Henry's constant, as calculated from pure component vapor pressure and aqueous solubility, was 10- to 170-fold greater than the experimental values. A correction to the Henry's constant that involves the ratio of the thermodynamic activity coefficient for a methyl siloxane at infinite dilution to that at saturation solubility in the aqueous phase is proposed.
The effect of stress on toxicant-dependent cytochrome P450 enzyme responses in the arctic charr (Salvelinus alpinus)
Authors: Jørgensen Even Hjalmar , Celander Malin , Goksøyr Anders , Iwata Munehico
Published: March 2010

In the present study we investigated the effect of stress and cortisol on cytochrome P450 (CYP) expression in Arctic charr exposed to benzo[a]pyrene (BaP). Expression of hepatic CYP1A and CYP3A was monitored 8 d after a single oral dose of BaP (10 mg/kg fish) and compared to that in unexposed fish. During this period the fish were subjected to one of the following stress regimes: no stress, no stress and cortisol implantation, 10 min of daily handling and confinement stress, and confinement stress during the last 6 h before sampling. In BaP-exposed fish daily stress resulted in significantly lower (53%) CYP1A protein levels as compared to those in unstressed fish. For CYP1A catalytic activity (measured as 7-ethoxyresorufin-O-deethylase [EROD] activity), the suppressive response to stress was less pronounced. These results contrast to previous findings of a potentiation by corticosteroids on xenobiotic-dependent CYP1A induction in vitro in cultured fish hepatic cells. No effects of high cortisol levels or BaP were found on the steroid-metabolizing CYP3A enzyme levels. The lack of any alterations in the CYP3A protein level indicates that CYP3A expression is not inducible by cortisol in the Arctic charr under the conditions used here. The conclusion was made that short-term stress associated with sampling (i.e., 6 h of confinement stress before sampling) of wild charr does not compromise the EROD activity as a reliable biomarker.
Toxicity identification of metals: Development of toxicity identification fingerprints
Authors: Van Sprang Patrick A , Janssen Colin R
Published: March 2010

The ecotoxicological and chemical response of five metals (Cd, Cr, Cu, Ni, and Zn) to selective fractionation techniques was assessed using the organism Daphnia magna. The metals Cu and Zn revealed similar toxicity patterns, showing an increased toxicity when lowering the pH, a marked reduction in toxicity after addition of ethylenediaminetetraacetic acid (EDTA). Similar toxicity reductions were obtained by passing the metal solutions over ion exchangers, activated charcoal, and filtration/solid-phase extraction units at neutral and basic pHs. The discrimination between Cu- and Zn-toxicity occurred in the oxidant reduction test, i.e., Zn toxicity was not affected by the addition of Na2S2O3, while Cu toxicity was strongly reduced. A second cluster was formed by Cd and Ni. The toxicity of both metals markedly decreased in the EDTA, ion exchangers, activated charcoal, filtration, and solid-phase extraction tests at high pHs. Discrimination between the toxicity of both metals was accomplished with the graduated pH test, in which a pH-independent toxicity response was found for Ni while the toxicity of Cd increased at lower pHs. Compared with the other metals, a very distinct toxicity pattern for Cr was observed. From the applied fractionation techniques, only the graduated pH and the anion resin tests resulted in a marked change in Cr toxicity. The produced toxicity patterns for each individual metal could therefore be used as fingerprints (i.e., toxicity identification fingerprints) in order to identify the toxicity caused by individual metals for D. magna.