bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of halogenated aromatic hydrocarbons and activities of cytochrome P450 and glutathiones-transferase in CRABS (Eriocheir japonicus) from Japanese Rivers
Authors: Ishizuka Mayumi , Sakiyama Takanori , Iwata Hisato , Fukushima Minoru , Kazusaka Akio , Fujita Shoichi
Published: March 2010

The hepatopancreases of freshwater crabs (Eriocheir japonicus) collected from three Japanese rivers (Barato, Shiribetsu, and Tone) were analyzed for planar halogenated aromatic hydrocarbons (HAHs), including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs). The hepatic glutathione S-transferase (GST)-dependent enzyme activities in the crab hepatopancreas were also measured to examine their potential as biomarkers for the contaminants. Crabs from the Tone River, which runs through industrial, agricultural, and urban areas, have the highest concentrations of HAHs (4,100 pg/g fat weight), followed by those from the Barato River (2,430-2,970 pg/g fat weight), whereas crabs from the Shiribetsu River were relatively less contaminated (1,350–1,800 pg/g fat weight). Identification of numerous PCDD and PCDF congeners in crabs from all three rivers provided evidence that one of the major sources of PCDDs and PCDFs was waste incineration. In addition, crabs from the Barato and Shiribetsu Rivers were notably contaminated with 1,3,6,8- and 1,3,7,9-TeCDD congeners, which suggests that a possible source was chlornitrofen, which has been extensively used in paddy fields as a herbicide. Calculation of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin toxic equivalents (TEQs) showed that the causal contaminants of higher TEQs in crabs from the Tone River (94.7 TEQ picograms per gram fat weight) were PCDDs and PCDFs, although the most important contributor to the total TEQs was coplanar PCBs (49.95%). The crab hepatopancreas appeared to have abilities to transfer glutathione to 1-chloro-2,4-nitrobenzene (CDNB) and 3,4-dichloronitrobenzene (DCNB). The crabs with the highest TEQ levels showed the highest GST activities. The current results and our previous data lead us to conclude that cytochrome P450 and GST-dependent enzyme activities (benzo[a]pyrene hydroxylation and CDNB and DCNB conjugation) in freshwater crab hepatopancreases are likely to be useful biomarkers for the contamination of planar aromatic hydrocarbons such as benzo[a]pyrene, PCDDs, PCDFs, and coplanar PCBs.
Induction of erod activity in HEPA-1 mouse hepatoma cells and estrogenicity in mcf-7 human breast cancer cells by extracts of pulp mill effluents, sludge, and sediment exposed to effluents
Authors: Koistinen Jaana , Soimasuo Markus , Tukia Kari , Oikari Aimo , Blankenship Alan , Giesy John P
Published: March 2010

Extracts of effluents and sludges from the primary and secondary clarifiers of an activated sludge treatment plant at a Finnish bleached kraft pulp and paper mill were analyzed in two cell bioassays. Total dioxin-like activities were determined by measuring the induction of ethoxyresorufin-O-deethylase (EROD) activity in Hepa-1 mouse hepatoma cells. Estrogenicity was studied by measuring luciferase activity in MCF-7 ERE-luc, which are MCF-7 human breast cancer cells stably transfected with an estrogen-responsive element linked to a luciferase promoter. Sediments collected near the pulp mill and from other sites in Lake Saimaa as well as fillets of whitefish exposed to effluents were examined and EROD activity was determined for complex mixtures of compounds extractable with dichloromethane (DCM) from the pulp mill effluent or compounds collected by semipermeable membrane devices (SPMDs) from the same effluent. Extracts of effluents, particulates, SPMDs, and sludges all caused measurable EROD induction. Because the induction potencies of the total DCM extract and the fraction of neutral compounds were similar, it was concluded that most of the EROD induction in pulp mill effluents was due to neutral compounds. Sediment collected from the vicinity of the pulp mill had greater EROD-inducing potency compared to that of the control sites from the same lake. Induction of EROD potencies of muscle extracts of whitefish exposed to diluted effluents were not significantly greater than those of control fish exposed to dilution water only. All extracts contained some estrogen agonist activity when tested in the MCF-7 bioassay.
Use of sublethal endpoints in sediment toxicity tests with the amphipod Hyalella azteca
Authors: Ingersoll Christopher G , Brunson Eric L , Dwyer F James , Hardesty Doug K , Kemble Nile E
Published: March 2010

Short-term sediment toxicity tests that only measure effects on survival can be used to identify high levels of contamination but may not be able to identify marginally contaminated sediments. The objective of the present study was to develop a method for determining the potential sublethal effects of contaminants associated with sediment on the amphipod Hyalella azteca (e.g., reproduction). Exposures to sediment were started with 7- to 8-d-old amphipods. On day 28, amphipods were isolated from the sediment and placed in water-only chambers where reproduction was measured on day 35 and 42. Typically, amphipods were first in amplexus at about day 21 to 28 with release of the first brood between day 28 to 42. Endpoints measured included survival (day 28, 35, and 42), growth (as length and weight on day 28 and 42), and reproduction (number of young/female produced from day 28 to 42). This method was used to evaluate a formulated sediment and field-collected sediments with low to moderate concentrations of contaminants. Survival of amphipods in these sediments was typically >85% after the 28-d sediment exposures and the 14-d holding period in water to measure reproduction. Reproduction was more variable than growth; hence, more replicates might be needed to establish statistical differences among treatments. Previous studies have demonstrated that growth of H. azteca in sediment tests often provides unique information that can be used to discriminate toxic effects of exposure to contaminants. Either length or weight can be measured in sediment tests with H. azteca. However, additional statistical options are available if length is measured on individual amphipods, such as nested analysis of variance that can account for variance in length within replicates. Ongoing water-only studies testing select contaminants will provide additional data on the relative sensitivity and variability of sublethal endpoints in toxicity tests with H. azteca.
Response of phytoplankton photosynthesis and growth to the aquatic herbicide hydrothol 191
Authors: Ruzycki Elaine M , Axler Richard P , Owen Christopher J , Martin Todd B
Published: March 2010

The herbicide Hydrothol 191, the amine salt of endothall, has been widely used for the control of aquatic vegetation and filamentous algae for over 30 years. Recently, it has been proposed for use in secondary wastewater stabilization ponds for control of algal-related total suspended solids (TSS) prior to and during discharge. However, published information on the effect of Hydrothol on algal growth and species-specific sensitivity is limited. We performed 96-h unialgal toxicity tests to determine effects on growth and photosynthetic activity on a number of species commonly found in these wastewater ponds. Results indicated differences in sensitivity to the herbicide between chlorophytes and cyanophytes. The 48-h 50% effective concentration (EC50) values for the blue-green Microcystis were 0.04 to 0.08 mg/L for cell growth and 0.04 to 0.22 mg/L for photosynthetic capacity; values for Phormidium were 0.05 mg/L and 0.097 mg/L for the same endpoints. The Chlorococcales greens Chlorella and Scenedesmus and the flagellated green Chlamydomonas showed much lower sensitivity to Hydrothol. The 48-h EC50 values for Chlorella were >0.60 mg/L for both cell growth and photosynthetic capacity while values for Scenedesmus were >0.60 mg/L and 0.23 mg/ L for the same parameters. The flagellate Chlamydomonas required 0.52 mg/L and 0.42 mg/L, respectively, to reduce cell density and photosynthetic capacity 50% below controls. These data suggest that reductions in the amount of Hydrothol needed to reduce algal-related TSS may be possible when the population is dominated by blue-greens that could be economically beneficial and allow for applications with reduced environmental concerns.
Acute toxicity of fire-retardant and foam-suppressant chemicals to early life stages of chinook salmon (Oncorhynchus tshawytscha)
Authors: Buhl Kevin J , Hamilton Steven J
Published: March 2010

Laboratorys studies were conducted to determine the acute toxicity of three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F), and two fire-suppressant foams (Phos-Chek WD-881 and Ansul Silv-Ex) to early life stages of chinook salmon, Oncorhynchus tshawytscha, in hard and soft water. Regardless of water type, swim-up fry and juveniles (60 and 90 d posthatch) exhibited similar sensitivities to each chemical and these life stages were more sensitive than eyed eggs. Foam suppressants were more toxic to each life stage than the fire retardants in both water types. The descending rank order of toxicity for these chemicals tested with swim-up fry and juveniles (range of 96-h median lethal concentrations [LC50s]) was Phos-Chek WD-881 (7–13 mg/L) > Ansul Silv-Ex (11–22 mg/L) > Phos-Chek D75-F (218–305 mg/L) > Fire-Trol GTS-R (218–412 mg/L) > Fire-Trol LCG-R (685–1,195 mg/L). Water type had a minor effect on the toxicity of these chemicals. Comparison of acute toxicity values with recommended application concentrations indicates that accidental inputs of these chemicals into stream environments would require substantial dilution (237- to 1,429-fold) to reach concentrations equivalent to their 96-h LC50s.
Effects of a mine tailings spill on feeding and metal concentrations in yellow perch (Perca flavescens)
Authors: Draves James F , Fox Michael G
Published: March 2010

In this study, we examined the effects of a gold mine tailings spill in the Montreal River (northern Ontario, Canada) on juvenile yellow perch (Perca flavescens), a benthic-feeding fish, and identified the major contributors to their uptake of tailings metals (Pb, Zn, Cd, and Cu) in dietary items and river water. Juvenile perch sampled from a 6-km reach of the river where most of the tailings were deposited had significantly less food in their stomachs than individuals sampled from a reference reach of the river. Concentrations of Pb in invertebrate prey taxa from the contaminated reach were 9 to 20 times higher than in those sampled from the reference reach. These differences were consistent with a higher concentration of Pb in perch from the contaminated reach. In contrast, Zn concentrations were high in river water and perch from both the reference and contaminated reaches, and little diffence was found in Zn concentration between invertebrate prey types sampled from the two reaches. No significant differences were found in Cu or Cd concentrations in yellow perch sampled from the two reaches. Higher levels of Pb in the major prey types from the contaminated reach indicate that dietary uptake may be the major vector for Pb accumulation in yellow perch from the Montreal River.
Applications of efficiency measurements in bioaccumulation studies: Definitions, clarifications, and a critique of methods
Authors: Penry Deborah L
Published: March 2010

Measurements of digestion, absorption, and assimilation efficiencies play central roles in physiological and ecological studies of nutrition and in toxicological studies of bioaccumulation. There is, however, a pervasive problem with inconsistency in the definition and use of efficiency terms and in their measurement and interpretation. Digestion, absorption, and assimilation efficiencies are frequently confused, and the term “assimilation efficiency” is commonly and incorrectly used as a synonym for digestion and absorption efficiencies. To differentiate measurements that are truly assimilation efficiencies from measurements that are digestion efficiencies and absorption efficiencies, explicit definitions of terms and examination of methodologies are necessary. In general, comparisons of ingested food and feces are digestion efficiencies and comparisons of ingested food and tissues are assimilation efficiencies. Absorption efficiencies can be determined from comparisons of ingested food and feces when the food component of interest is directly absorbed without digestion (e.g., some particle-associated toxicants) or is an absorbable tracer (e.g., 14C) that is not altered by digestion. Absorption efficiencies of toxicants are commonly measured using two tracer-based methods, the dual tracer method and the selectivity index (SI) method. The assumptions of the dual tracer method can at least be tested and validated while the assumptions of the SI method are not valid. The SI method requires the assumption of a value for total organic carbon (TOC) absorption efficiency in order to calculate a toxicant absorption efficiency, and analysis of the equations associated with the SI method shows that calculating a toxicant absorption efficiency using an assumed TOC absorption efficiency is not any more justifiable than just assuming a toxicant absorption efficiency.
Evidence for long-range transport of a low to medium molecular-weight petroleum product off Central California, USA
Authors: Phillips Charles , Clayton John , Evans John , Hom Wilson
Published: March 2010

Suspended particles collected within southern Santa Maria Basin (CA, USA) during November 1991 contained unusually elevated concentrations of parent and alkylated polycyclic aromatic hydrocarbons (PAHs) and patterns in straight chain alkanes and saturated biomarkers (terpanes and steranes) indicative of contamination by a distilled petroleum product from a California-sourced oil. Because no active offshore oil and gas drilling was occurring at the time, and there was no record of diesel spills or evidence from previous samplings of discharges of diesel fuel-contaminated drilling muds, petroleum hydrocarbons in the suspended sediments likely were related to a source other than platform discharges. The timing as well as the hydrocarbon composition suggested the presence of a petroleum product (diluent) that was released from an oil field at Guadalupe, approximately 50 km north of Santa Maria Basin. To evaluate diluent contributions, the hydrocarbon composition of suspended sediments was characterized and compared to those of possible source materials, including diluent, formation oils, and well cuttings, using principal component analysis (PCA). Suites of saturated and aromatic hydrocarbons, enriched in the C13 to C23 range, contained in some suspended sediments were consistent with relative abundances of low to medium molecular weight components in diluent but were different from those in formation and seep oils. Results of the PCA support the compositional similarities between the diluent and affected suspended sediments. This suggests that a petroleum product was transported as an oil-particle mixture over long distances with relatively minimal degradation. Wide dispersion of diluent increased potential exposures of marine organisms to toxic lower molecular weight PAHs.
Kinetics of tetrachloroethylene-reductive dechlorination catalyzed by vitamin B12
Authors: Burris David R , Delcomyn Carrie A , Deng Baolin , Buck Leslie E , Hatfield Kirk
Published: March 2010

Reductive dechlorination kinetics of tetrachloroethylene (PCE) to ethylene catalyzed by vitamin B12 using Ti[III] citrate as the bulk reductant was examined in a vapor/water batch system. A kinetic model incorporating substrate–B12 electron-transfer complex formation and subsequent product release was developed. The model also accounted for the primary reductive dechlorination pathways (hydrogenolysis and reductive β elimination) and vapor/water-phase partitioning. Reaction rate constants were sequentially determined by fitting the model to experimental kinetic data while moving upward through consecutive reaction pathways. The release of product from the complex was found to be second order with respect to substrate concentration for both PCE and acetylene; all other substrates appeared to release by first order. Reductive β elimination was found to be a significant reaction pathway for trichloroethylene (TCE), and chloroacetylene was observed as a reactive intermediate. Acetylene production appears to be primarily due to the reduction of chloroacetylene derived from TCE. The reduction of cis-dichloroethylene (cis-DCE), the primary DCE isomer formed, was extremely slow, leading to a significant buildup of cis-DCE. The kinetics of acetylene and vinyl chloride reduction appeared to be limited by the formation of relatively stable substrate–B12 complexes. The relatively simple model examined appears to adequately represent the main features of the experimental data.
Aquatic biodegradation behavior of pentachlorophenol assessed through a battery of shake flask die-away tests
Authors: Ingerslev Flemming , Baun Anders , Nyholm Niels
Published: March 2010

The aerobic aquatic biodegradability of pentachlorophenol (PCP) was studied in standard Organization for Economic Cooperation and Development/International Organization for Standardization shake flask screening tests for ready biodegradability and in more environmentally realistic surface water die-away tests with low chemical concentrations. Screening tests were conducted with either activated sludge or supernatant from settled activated sludge. Concentrations of activated sludge were 30 and 0.3 mg suspended solids per liter. Sludges were either freshly collected or initially preexposed to PCP. With supernatant, only low inoculum levels were used (0.5 ml/L). Some surface water tests were carried out with sediment amendment. Added chemical concentrations ranged from 1 to 74,000 μg/L. At nontoxic concentrations, PCP was rapidly biodegradable after an adaptation period of about 10 to 20 d. At concentrations below about 10 μg/L, degradation rates decreased, and the shape of the degradation curves indicated a shift from growth-linked degradation to non-growth-linked degradation. Addition of sediment to surface water reduced the acclimation periods but did not influence the subsequent degradation rate. Preexposure of activated sludge to PCP drastically eliminated the acclimation period and increased the tolerance of the sludge to PCP toxicity. With PCP used as a model compound, the results show that a battery of simple shake flask tests is suitable for provision of a detailed characterization of the biodegradability chemical compounds.
Bioaccumulation of polycyclic aromatic hydrocarbons by earthworms: Assessment of equilibrium partitioning theory in in situ studies and water experiments
Authors: Ma Wei-chun , van Kleunen André , Immerzeel Jaap , de Maagd P Gert-Jan
Published: March 2010

The purpose of this study was to assess the suitability of applying equilibrium partitioning (EqP) theory to predict the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) by earthworms when these are exposed to contaminated soils in the field. Studies carried out in situ in various contaminated floodplain sites showed the presence of linear relationships with intercept zero between the lipid-normalized concentration of different PAHs in the earthworm Lumbricus rubellus and the organic-matter-normalized concentration of the compounds in soil. The demonstration of such an isometric relationship is in agreement with the prediction of EqP theory that the biota-soil accumulation factor (BSAF) should be independent of the octanol/water partition coefficient, log Kow. The average BSAF of PAH compounds in the sampled 20-cm top layer of soil was 0.10 (range, 0.03–0.26). The present study also investigated the route of uptake of PAHs for earthworms in soil. The bioconcentration factor of low-molecular-weight PAHs, such as phenanthrene, fluoranthene, and pyrene, was derived from bioconcentration kinetic modeling of water-only experiments and found to be of the same order of magnitude as the bioaccumulation factor in the field when the latter was normalized to calculated concentrations in soil pore water. The results indicated that the exposure of earthworms to PAHs in soil is mediated through direct contact of the worms with the dissolved interstitial soil-water phase, further supporting the applicability of EqP theory to PAHs. Our experimental data on the biotransformation of PAHs suggest that earthworms possess some capacity of metabolization, although this does not seem to be a major factor in the total elimination of these compounds. Even though the EqP approach was found to be applicable to low-molecular-weight PAHs with respect to the prediction of bioaccumulation by earthworms in the field, the results were less conclusive for high-molecular-weight compounds, such as benzo[a]pyrene.
Use of semipermeable membrane devices for studying effects of organic pollutants: Comparison of pesticide uptake by semipermeable membrane devices and mussels
Authors: Sabaliünas Darius , Lazutka Juozas , Sabaliüniene Inesa , Södergren Anders
Published: March 2010

Uptake of four pesticides—the organochlorines chlordane and endosulfan and the synthetic pyrethroids fenvalerate and allethrin—by triolein-containing semipermeable membrane devices (SPMD) and by the lake mussel Anodonta piscinalis was studied in a laboratory continuous-flow system. Uptake of the analytes by the SPMDs and mussels was linear during the exposure period of 20 d. These kinetic data were used to calculate the first-order uptake rate constants. On a SPMD-whole body basis, the uptake rates were 3.5 to 5.5 times higher in the membrane devices than in the organisms. The synthetic pyrethroids were sampled at lower rates than the organochlorines, and this difference may be attributed to the larger molecular dimensions of the pyrethroids rather than analyte molecular weight and lipophilicity, which were similar for all test compounds. Because of the disparate sampling rates, concentration factors of analytes differed between SPMDs and mussels. However, the percent composition (ratios) of analytes in SPMDs and in mussels was similar, which indicates that SPMDs may serve as good surrogates for aquatic organisms with respect to the discriminatory uptake of hydrophobic chemicals. Semipermeable membrane device dialysate, mussel extract, as well as two artificial mixtures of the four pesticides were tested with standard toxicity and genotoxicity tests, including Microtox® (inhibition of bacterial luminescence), Daphtoxkit™, and Rotoxkit™ (toxicity tests with freshwater invertebrates Daphnia pulex and Brachionus calyciflorus, respectively), and sister chromatid exchange in human lymphocytes in in vitro assay. Results of these tests suggest that integration of the SPMD technique and bioassays may be a valuable approach for the assessment of levels and effects of bioavailable hydrophobic pollutants.
Promutagen activation by the green algaSelenastrum capricornutum
Authors: Sauser Kathleen R , Chung King-Thom , Wong Tit-Yee
Published: March 2010

The capability of Selenastrum capricornutum to activate o-phenylenediamine (OPD) and 2-aminofluorene (2-AF) was tested in a modified Ames assay in which the activation component (S9) was replaced by the algal cells. Normal-grown algae did not activate OPD but these cells activated 2-AF by sixfold. Copper induces a peroxidase in S. capricornutum. Algae pregrown on copper-enriched medium increased the mutagenicity of OPD by more than 16-fold, but these cells failed to further activate 2-AF. However, 2-AF was further activated by algae pretreated with flavone, Aroclor, 5,6-naphthoflavone, or 2,4-dichlorophenoxyacetic acid, but not lindane or ethanol. This suggested that a cytochrome P450 system was involved in 2-AF activation. Coincubating algae with cytochrome P450 inhibitors including diethyldithiocarbamate, methimizole, or acetaminophen, but not catechin, 7–8-naphthoflavone, or CuCl2 reduced the activation level of 2-AF significantly.
Effects of tributyltin on a coastal North Sea plankton community in enclosures
Authors: Jak Robbert G , Ceulemans Michiel , Scholten Martin C Th , van Straalen Nico M
Published: March 2010

The toxicity of tributyltin (TBT) to a neritic North Sea plankton community was studied in experiments using outdoor enclosures with a volume of 1.2 m3. Nominal TBT concentrations of 0, 0.056, 0.1, 0.18, 0.32, and 0.56 μg/L were tested in duplicate for 28 d. A first-order decrease of TBT in the water column was observed for the highest nominal concentration, with a rate constant of 0.12 per day (t½ of 5.7 d). Median effective concentration (EC50) values were determined for the dominant zooplankton species, Temora longicornis (Copepoda). The EC50 values were lower when calculated for biomass than when calculated for density and ranged between 0.15 and 0.32 μg/L, depending on exposure time. At high TBT concentrations, enhanced pH levels and oxygen concentrations were observed, indicating high algal production levels, which would result from reduced grazing by zooplankton. Depending on exposure time, EC50 values for the indirect effect of TBT on pH varied between 0.10 and 0.22 μg/L, indicating that the indirect effects of TBT are at least as sensitive as the direct effects. The study showed that testing chemicals in outdoor enclosures can provide data complementary to that obtained from laboratory toxicity tests.
Toxic cell concentrations of three polychlorinated biphenyl congeners in the green alga Selenastrum capricornutum
Authors: Mayer Philipp , Halling-Sørensen Bent , Sijm Dick T H M , Nyholm Niels
Published: March 2010

Algal growth inhibition tests were performed with the unicellular green alga Selenastrum capricornutum and three 14C-labeled polychlorinated biphenyl (PCB) congeners. Toxicity was related to external aqueous concentrations and additionally to internal algal bound PCB concentrations. Estimates of the concentrations at 50% effectiveness (EC50s) for the three PCB congeners ranged within a factor of 17 (14–241 nmol/L) when based on measured aqueous concentrations. When based on internal toxicant concentrations (toxic cell concentrations, TCC50) the corresponding range was 6.7 to 14.3 mmol/kg wet weight. Thus, changing the basis from external to internal concentrations reduced the range by almost one order of magnitude. Additional toxic cell concentrations of five monoaromatic compounds and S. capricornutum were calculated from literature data to be in the same order of magnitude as the experimental toxic cell concentrations for the PCBs, whereas EC50 values for all substances ranged by more than four orders of magnitude. The experimental and calculated data indicate that observed differences in the estimated EC50 values were mainly due to differences in bioconcentration behavior rather than to different intrinsic toxicities. These findings are in agreement with the concept of baseline toxicity, meaning that a number of hydrophobic organics exerts their acute toxicity by one relatively nonspecific mode of action.
Chronic toxicity of pulse-dosed fenoxycarb toDaphnia magnaexposed to environmentally realistic concentrations
Authors: Hosmer Alan J , Warren Laurie W , Ward Timothy J
Published: March 2010

Effects of fenoxycarb on growth and reproduction of Daphnia magna were examined under realistic exposure conditions as defined by predictions from laboratory fate studies and observations in the field. Initial concentrations were administered in a single pulse dose and altered to mimic the reduction of fenoxycarb that occurs following field application to natural waters (half-life ⋍ 10 hours). Potential effects on the developmental stage of test organisms were determined by exposure of four age groups: less than 24 h, 4 to 6 d, 8 d, and 11d. There were no significant effects on survival or time to first brood of first- and second-generation daphnids in any age group. The number of young per daphnid was significantly lower than controls only among daphnids that were less than 24 h old at test initiation and exposed to the highest initial measured concentration of fenoxycarb (45 μg/L). The estimated maximum acceptable toxicant concentration (MATC) was 26 μg/L, calculated from exposure of the most sensitive age group (less than 24 h old) to environmentally realistic levels of fenoxycarb. This represents a substantial reduction in toxicity when compared to the MATC of 0.0016 μg/L previously reported from a standard, constant-exposure study.
Desulfonation of biotransformation products from commercial linear alkylbenzenesulfonates
Authors: Mampel Jörg , Hitzler Tanja , Ritter Axel , Cook Alasdair M
Published: March 2010

Earlier work shows that the biodegradation and biotransformation of commercial linear alkylbenzenesulfonate (LAS) as a carbon source for growth leads to a residue of sulfonated aromatic compounds, termed refractory organic carbon, from the synthetic by-products. We now show that this refractory organic carbon, after separation from sulfate ion, is utilized extensively as a sulfur source for bacterial growth. The products of desulfonation are expected to be biodegradable, so we question the value of adjectives like refractory.
Atrazine effects on estuarine macrophytes Spartina alterniflora and Juncus roemerianus
Authors: Lytle Julia S , Lytle Thomas F
Published: March 2010

Two dominant estuarine marsh plants, Juncus roemerianus and Spartina alterniflora, were exposed for 35 d to three dose levels of atrazine with measured concentrations of approximately 0.03, 0.25, and 3 mg/L to assess peroxidase (POD) activity, lipid peroxidation, chlorophyll changes, and growth rates. The objective of the study was to evaluate toxicity of atrazine and to measure multiple endpoints to assess their value as biomarkers of atrazine stress or resistance. In S. alterniflora, exposure to 3.1 mg/L of atrazine did not significantly inhibit growth, generated no lipid peroxidation products, and did not affect chlorophyll production, but did significantly enhance POD activity. In contrast, in J. roemerianus, atrazine exposure significantly inhibited growth at 3.8 mg/L, produced lipid peroxidation products and inhibited chlorophyll production in a dose-response fashion, and did not elicit a POD response. In combination, POD activity and lipid peroxidation are useful indicators of atrazine stress to these plants. Results of the study indicate that J. roemerianus would decline or die off if exposed to chronically high environmental concentrations of atrazine, whereas minimal damage would occur to S. alterniflora.
Unexpectedly high mercury level in pelleted commercial fish feed
Authors: Choi Monica Heekyoung , Cech Joseph J
Published: March 2010

An unexpectedly high mercury (Hg) level was found in a pelleted commercial fish feed used to feed fish in laboratory and fish farm settings. Mean total Hg (T-Hg) concentration in the commercial fish pellets was 66 ppb (ranging from 35 to 90 ppb). Mean total selenium (T-Se) concentration in the pellets was 1,120 ppb (ranging from 790 to 1,360 ppb). Total Hg and Se in the whole blood of Sacramento blackfish and in the fish feed were determined by inductively coupled plasma-mass spectrometry (ICP-MS). During a 10-week sampling period T-Hg in blood fluctuated between 35 and 56 ppb. A highly significant, positive correlation (r = 0.99, p < 0.01) was found between T-Hg in the fish blood and in the fish feed through the sampling period. On the other hand, no correlation was found between T-Se in the fish feed and T-Hg or T-Se blood level. Researchers working with fish in Hg studies need to know that fish pellets may contain Hg and to consider the influence of these pellets in their results.
Genetics of radionuclide-contaminated mosquitofish populations and homology between Gambusia affinis and G. holbrooki
Authors: Theodorakis Christopher W , Bickham John W , Elbl Tricia , Shugart Lee R , Chesser Ronald K
Published: March 2010

The effects of radionuclide contamination on genetic structure of eastern mosquitofish (Gambusia holbrooki) populations from the U.S. Department of Energy's Savannah River Site (SRS) were investigated to develop methods of assessing ecological risk of chronic exposures to xenobiotics. Fish from two contaminated and two reference sites were examined by the randomly amplified polymorphic DNA (RAPD) technique, which revealed that the frequency of three markers was greater in the contaminated than the reference sites and that the frequency of two markers was greater in the reference than in the contaminated sites. A previous study examined populations of western mosquitofish (G. affinis) from the Oak Ridge National Laboratory (ORNL) and found that certain RAPD markers were present in radionuclide-contaminated ORNL populations at a higher frequency than in reference populations. The “contaminant-indicative” markers observed in the SRS populations were the same size and amplified by the same polymerase chain reaction primers used in the ORNL study. Southern blot analysis revealed that the SRS G. holbrooki contaminant-indicative markers were homologous to the ORNL G. affinis contaminant-indicative markers. The observation that two species show similar patterns of band frequency shifts at two separate localities is consistent with the hypothesis that these DNA markers may originate from genetic elements that provide a selective advantage in contaminated habitats. Thus, the methodology used in these studies may prove to be useful to indicate population-level effects of environmental contamination.
In vitro induction of ethoxyresorufin-O-deethylase and porphyrins by halogenated aromatic hydrocarbons in avian primary hepatocytes
Authors: Sanderson J Thomas , Kennedy Sean W , Giesy John P
Published: March 2010

Ethoxyresorufin-O-deethylase (EROD) and porphyrin induction responses of primary hepatocytes to halogenated aromatic hydrocarbons (HAHs) were examined in newly hatched domestic chickens, herring gulls, ring-billed gulls, double-crested cormorants, and Forster's terns. Concentration–response relationships were determined for both biochemical responses in hepatocyte preparations derived from individual avian livers (except for the tern). The choice of vehicle used to dose chicken hepatocytes greatly affected the potencies and efficacies of HAHs. Dimethyl sulfoxide resulted in median effective concentration (EC50) values for EROD induction that were between 10 and 15 times less than isooctane (isooctane was used throughout the study). Neither vehicle induced EROD activity by itself. Concentration-dependent increases in EROD activity were observed with several HAHs, and their potencies (EC50 values) were compared to that of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) within each hepatocyte preparation to determine relative potency factors (RPFs). Differences in sensitivity to these responses were observed among individuals within each of the species and among species. Median EC50 values (nM) for EROD induction by TCDD were 0.72, 13, 20, 25, and 150 for the chicken, cormorant, ring-billed gull, herring gull, and tern hatchling, respectively. Relative potency factors for several HAHs were different, in both ranking and potency, from those generally derived in mammalian hepatocytes. Porphyrin accumulation was observed occasionally with the most potent aryl hydrocarbon receptor agonists, but most HAHs were not tested at concentrations sufficiently high to observe a consistent response. This study provides information on interindividual and interspecies differences in responsiveness to TCDD-like compounds and provides species-specific RPFs that may prove useful for the purpose of hazard and risk assessment for fish-eating birds.
Accumulation and depuration of sediment-sorbed C12- and C16-polychlorinated alkanes by oligochaetes (Lumbriculus variegatus)
Authors: Fisk Aaron T , Wiens Susanna C , Webster G R Barrie , Bergman Åke , Muir Derek C.G
Published: March 2010

Oligochaetes (Lumbriculus variegatus) were exposed to sediment spiked with four 14C-polychlorinated alkanes (PCAs) (C12H20C16 [56% Cl by weight], C12H16Cl10 [69% Cl], C16H31Cl3 [35% Cl], and C16H21Cl13 [69% Cl]) to measure bioaccumulation parameters and biotransformation. Chlorinated paraffins are industrial products that consist of thousands of different PCAs. Chlorinated paraffins are hydrophobic (log octanol–water partition coefficients [Kows] > 5.0) and are reported to have relatively high concentrations in sediment compared with other persistent organochlorines; however, no data exist on their bioavailability from sediment. The PCAs C12H20Cl6, C12H16Cl10, and C16H31Cl3 were readily available to sediment-ingesting oligochaetes, whereas C16H21Cl13 had lower bioavailability. Uptake rates of the C12-PCAs were greater than the C16-PCAs, but half-lives (t½s) were greater for the C16-PCAs (t½ = 30-33 d) than for the C12-PCAs (t½ = 12-14 d). Biota–sediment accumulation factors were >1 for C12H20Cl6, C12H16Cl10, and C16H31Cl3, but <1 for C16H21Cl13. Comparison of toluene-extractable and -nonextractable 14C suggest that PCAs were biotransformed in aerobic sediments and by oligochaetes, and that the susceptibility to degradation in sediments decreases with increasing chlorine content. The relative abundance of individual PCAs may differ between sediment and benthic invertebrates because of differences in the bioaccumulation and degradation of PCAs of varying carbon chain length and chlorine content.
Energetic and behavioral responses by the common goby,Pomatoschistus microps(krøyer), exposed to linear alkylbenzene sulfonate
Authors: Christiansen Per Dahl , Brozek Morten , Hansen Benni Winding
Published: March 2010

The acute toxicity of linear alkylbenzene sulfonate (LAS) on the common goby (Pomatoschistus microps), an estuarine fish, was established during a 96-h static exposure. The median lethal concentration was 2.6 ± 0.49 mg LAS/L (mean ± 95% confidence limit). The acute behavioral responses to LAS at different concentrations were excess mucus secretion and apathy at 1.0 mg/L; air gulping, distension of the mouth and opercula, change in pigmentation, and erratic swimming at 2.0 to 3.0 mg/L; and loss of balance and reactivity at ≤4.0 mg/L. The frequency of operculum opening increased with increasing LAS concentrations and appeared at 4.0 mg/L, with a significant doubling in relation to the frequency observed in control fish (p = 0.025). The physiological responses by P. microps after prolonged exposure to sublethal and environmentally realistic concentrations of LAS (0.05-1.0 mg/L) were observed under semistatic conditions in the laboratory. Ingestion, respiration, and growth were also measured during 28 d of exposure. A significant decrease in growth and respiration was found at 0.1 mg LAS/L (p = 0.049 and 0.033, respectively), but ingestion was not affected. The effect concentrations for growth and respiration represent the lowest-observed-effect concentrations, which are both lower than values previously reported for fish. Gross conversion efficiency was affected negatively at 1.0 mg LAS/L (p = 0.001). Pomatoschistus microps is recommended as a suitable and relevant test organism for ecotoxicological experiments.
A simple apparatus for administering 2,3,7,8-tetrachlorodibenzo-p-dioxin to commercially available pelletized fish food
Authors: Fernandez Joseph D , Denny Jeffrey S , Tietge Joseph E
Published: March 2010

A simple apparatus for loading chemicals onto commercially available, pelletized fish food is described. An analysis of several food nutrients indicated the procedure using n-hexane (50 ml n-hexane:200 g food) had an inconsequential influence on their concentrations, i.e., only lauric acid and margaroleic acid exhibited reductions ≥ 10%, 25%, and 17%, respectively. Of 35 batches of food laden with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), only 40% of the loadings were within 10% of the desired value. However, in terms of the within-batch variability, all loadings exhibited a coefficient of variation (CV) ≤15%, and over 60% of the loadings exhibited a CV ≤10%.
Mercury and plants in contaminated soils: 1. Uptake, partitioning, and emission to the atmosphere
Authors: Leonard Todd L , Taylor George E , Gustin Mae S , Fernandez George C.J
Published: March 2010

The uptake, distribution, and subsequent emission of mercury to the atmosphere were investigated in five plant species (Lepidium latifolium [L.], Artemisia douglasiana [Bess in Hook], Caulanthus sp. [S. Watson], Fragaria vesca [L.], and Eucalyptus globulus [Labill]) with different ecological and physiological attributes. Transfer coefficients for mercury in the soil-plant system were calculated. Plant-to-atmosphere emissions of mercury were determined using a controlled environment gas-exchange system and ranged from 10 to 93 ng/m2/h in the light; emissions in the dark were an order of magnitude less. Transfer coefficients for mercury within the soil-plant system increased acropetally (root-to-leaf axis) by orders of magnitude. Estimated mercury emissions from plants in the Carson River Drainage Basin of Nevada over the growing season (0.5 mg/m2) add to the previously reported soil mercury emissions (8.5 mg/m2), resulting in total landscape emissions of 9 mg/m2. For L. latifolium, 70% of the mercury taken up by the roots during the growing season was emitted to the atmosphere. For every one molecule of mercury retained in foliage of L. latifolium, 12 molecules of mercury were emitted. Within this arid ecosystem, mercury emissions are a dominant pathway of the mercury cycle. Plants function as conduits for the interfacial transport of mercury from the geosphere to the atmosphere, and this role is undervalued in models of the behavior of mercury in terrestrial ecosystems and in the atmosphere on a global scale.
Hydrolysis of genotoxic methyl-substituted oxiranes: Experimental kinetic and semiempirical studies
Authors: Kirkovsky Leonid I , Lermontov Sergei A , Zavorin Sergei I , Sukhozhenko Ivan I , Zavelsky Vladimir I , Thier Ricarda , Bolt Hermann M
Published: March 2010

The kinetics of acid-catalyzed hydrolysis of seven methylated aliphatic epoxides—R1R2C(O)CR3R4 (A: R1=R2=R3=R4=H; B: R1=R2=R3=H, R4=Me; C: R1=R2=H, R3=R4=Me; D: R1=R3=H, R2=R4=Me(trans); E: R1=R3=H, R2=R4=Me(cis); F: R1=R3=R4=Me, R2=H; G: R1=R2=R3=R4=Me)—has beens studied at 36 ± 1.5°C. Compounds with two methyl groups at the same carbon atom of the oxirane ring exhibit highest rate constants (keff in reciprocal molar concentration per second: 11.0 ± 1.3 for C, 10.7 ± 2.1 for F, and 8.7 ± 0.7 for G as opposed to 0.124 ± 0.003 for B, 0.305 ± 0.003 for D, and 0.635 ± 0.036 for E). Ethylene oxide (A) displays the lowest rate of hydrolysis (0.027 M−1 s−1). The results are consistent with literature data available for compounds A, B, and C. To model the reactivities we have employed quantum chemical calculations (MNDO, AM1, PM3, and MINDO/3) of the main reaction species. There is a correlation of the logarithm keff with the total energy of epoxide ring opening. The best correlation coefficients (r) were obtained using the AM1 and MNDO methods (0.966 and 0.957, respectively). However, unlike MNDO, AM1 predicts approximately zero energy barriers for the oxirane ring opening of compounds B, C, F, and G, which is not consistent with published kinetic data. Thus, the MNDO method provides a preferential means of modeling the acidic hydrolysis of the series of methylated oxiranes. The general ranking of mutagenicity in vitro, A > B > C, is in line with the concept that this sequence also gradually leaves the expoxide reactivity optimal for genotoxicity toward reactivities leading to higher biological detoxifications.
Digestive determinants of benzo[a]pyrene and phenanthrene bioaccumulation by a deposit-feeding polychaete
Authors: Penry Deborah L , Weston Donald P
Published: March 2010

The uptake of hydrophobic contaminants from ingested sediment can contribute significantly to body burdens of deposit feeders, and feeding behavior and digestive physiology can play important roles in bioaccumulation. We examined the uptake of polycyclic aromatic hydrocarbons (PAHs) by the deposit-feeding polychaete Abarenicola pacifica in experiments in which worms were first acclimated to low or high organic carbon sediments with 0.08 or 0.45% total organic carbon, respectively and then transferred to low or high organic carbon test sediments contaminated with radiolabeled phenanthrene or benzo[a]pyrene. Ingestion rate was a strong determinant of rates (benzo[a]pyrene) or extents (phenanthrene) of PAH uptake. Ingestion rate measurements are essential in many types of bioaccumulation studies because differences in ingestion rates between sediment types may confound some traditional measures of bioavailability. Physiological acclimation to the low or high organic carbon sediments did not appear to affect PAH uptake from the test sediments, but acclimation did affect biotransformation capabilities, particularly for phenanthrene.
Pigmented skin tumors in gizzard shad (Dorosoma cepedianum) from the south-central United States: Range extension and further etiological studies
Authors: Geter David R , Hawkins William E , Means Jay C , Ostrander Gary K
Published: March 2010

Previous studies reported skin tumors diagnosed as pigmented subcutaneous spindle-cell neoplasms in 22% of gizzard shad (Dorosoma cepedianum) from Lake of the Arbuckles, Oklahoma, USA. Those studies could not confirm chemical carcinogens or retroviruses as etiological agents. The present study reports the neoplasms in 20% of shad from two additional lakes, Lake Murray and Lake Texoma in south-central Oklahoma, extending the range of the lesion. No neoplasms were found in shad from a reference site, Lake Carl Blackwell, Oklahoma. Further investigations into the etiology of the lesions were conducted. Significant levels of potentially carcinogenic trace elements in the water, sediment, or tissues were not identified by inductively coupled plasma mass spectrometry. Radioactivity, analyzed by liquid scintillation counting of radon and gross alpha/beta radiation, was not above background levels. Genetic marker and band-sharing analysis by random amplified polymorphic DNA and double-stringency polymerase chain reaction could not separate tumor-bearing shad from nontumor-bearing ones. Of 2,128 shad examined, 387 exhibited lesions, with a significantly higher number occurring dorsally (79.5%) than ventrally (20.5%). Overall, this study showed the epizootic is not limited to a single lake and tended to rule out some known carcinogens and radioactivity as proximate causes of the epizootic.
Relationship between oxygen consumption and sediment-water fluxes of heavy metals in coastal marine sediments
Authors: Shine James P , Ika Raveendra , Ford Timothy E
Published: March 2010

The relationship between benthic oxygen demand and the sediment–water flux of six heavy metals (cobolt [Co], nickel [Ni], copper [Cu], zinc [Zn], cadmium [Cd], and lead [Pb]) was examined at two locations: New Bedford Harbor and Buzzards Bay, Massachusetts, USA. Dissolved metal fluxes were measured in laboratory microcosms incubated in the dark at in situ temperatures, and microcosms were collected over different seasons to examine temporal and spatial variability in the fluxes. The net flux of all metals was generally out of the sediments. However, at low rates of benthic oxygen demand, net flux of Pb and Co was into the sediments. When data from the two sites are combined, regression of metal fluxes (normalized to sediment metal content) against benthic oxygen demand was significant for all metals (r2 = 0.58-0.85), with all slopes significantly different from zero. The flux values (normalized to sediment metal content) ranged from -1.4 (mmole/m2/d)/(mole/mole C)sediment for Zn during winter to 42 (mmole/m2/d)/(mole/mole C)sediment for Cd during summer months. The magnitude of the fluxes generally showed the following relationship: Cd < Zn < Co, Ni, Cu < Pb, indicating higher relative mobility for Cd and lower mobility for Pb. The estimated annual fluxes of metals to New Bedford Harbor and Buzzards Bay amount to ˜0.06% (Pb) to 25% (Cd) of the inventory of metals in the top 2 cm of sediments and can equal the inventory of metals in the water column on a time scale as short as 7 d for Zn.