bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute sensitivity of nematode taxa to CuSO4 and relationships with feeding-type and life-history classification
Authors: Bongers Tom , Ilieva-Makulec Krassimira , Ekschmitt Klemens
Published: March 2010

The acute sensitivity to CuSO4 of a broad range of nematode taxa was analyzed in order to assess the potential of changes to nematode community structure to serve as a practical tool for the bioindication of heavy-metal pollution. An easy-to-use experimental set-up was developed along with an appropriate mathematical response model in order to quantify the response characteristics of nematodes to CuSO4 pressure. Three similar experiments were conducted using water, dune sand, and sandy soil as media, each of which was subjected to 12 increasing concentrations of CuSO4. In total, 130 response curves representing 70 nematode taxa were produced and analyzed. CuSO4 concentrations were normalized for differences in efficiency among media due to different adsorption. At low CuSO4 concentrations, many taxa exhibited stimulation rather than inhibition regarding recovery efficiency. At higher concentrations, the concentration level at which 50% of the nematode population was recovered after a 24-h incubation (recovery concentration 50% [RC50]) varied widely among taxa and ranged from 0.01 to 4 mM/L CuSO4 (normalized to water). Stimulation of recovery efficiency and RC50 were negatively correlated with the colonizer-persister (C-P) classification of taxa, which discriminates nematodes according to their reproductive potential. The maturity index, which relates to a nematode community's state of disturbance and eutrophication, was negatively correlated with CuSO4 concentration. The properties of the applied test method are discussed as are the relationships between the investigated short-term toxicity effects and long-term toxicity processes in the field. From the large range of observed RC50 values, it is concluded that a meaningful sensitivity classification of nematodes should be possible and thus would allow for a sensitive bioindication of heavy-metal pollution. From the correlation between RC50 and C-P classification, the authors further conclude that the maturity index will, in addition to enrichment and disturbance, respond to heavy-metal pollution and thus may serve as a general indicator of soil health.
Phototoxicity of azaarene isomers to the marine flagellateDunaliella tertiolecta
Authors: Wiegman Saskia , van Vlaardingen Peter L A , Bleeker Eric A J , de Voogt Pim , Kraak Michiel H S
Published: March 2010

Many studies have shown that narcosis or baseline toxicity of polycyclic aromatic hydrocarbons (PAHs) is strongly related to their lipophilicity. For azaarenes, such relationships have also been demonstrated, but for some compounds, deviations from these relationships have been observed, even for closely related compounds such as isomers. In the present study, the toxicity of four azaarene isomer pairs to the marine flagellate Dunaliella tertiolecta was determined. For quinoline, isoquinoline, acridine, phenanthridine, benz[a]acridine, and benz[c]acridine, the 72-h median effective concentrations for growth were 571, 464, 2.10, 14.7, 0.50, and 0.11 μM, respectively. For the five-ringed isomers dibenz[a,i]acridine and dibenz[c,h]acridine, no effects were observed at the highest concentration tested (0.1 and 0.005 μM, respectively). Growth inhibition by the two-, three-, and fourringed isomer pairs to D. tertiolecta was well described by molecular volume and log Kow, indicating a narcotic mode of action. However, the toxicity of acridine and benz[c]acridine was much higher than that of their respective isomers, phenanthridine and benz[a]acridine, suggesting an additional specific mode of action. Based on the differences in energies between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, acridine and benz[c]acridine are susceptible to ultraviolet (UV) radiation, in contrast to the other tested compounds. Because UV was present, it is therefore argued that the toxicity of both compounds was photoenhanced. Photoenhanced toxicity may increase the environmental hazard of azaarenes, indicating the importance of enlarging the present monitoring of PAHs with phototoxic N-heterocyclic PAHs and incorporating this mode of action in water-quality criteria.
Annual and regional variation in mercury concentrations in wood stork nestlings
Authors: Gariboldi Joan C , Bryan A. Lawrence , Jagoe Charles H
Published: March 2010

Mercury concentrations were measured in blood, down, and feathers from approximately 300 wood stork nestlings in one South Carolina, USA, and four Georgia, USA, colonies from 1996 to 1999. Coastal nestlings generally had lower mercury concentrations than those from inland colonies. Interyear differences were also apparent, particularly for coastal colonies, where nestling mercury concentrations were higher in 1998 than in 1997 or 1999. In 1998, a wet winter followed by a dry spring and summer produced ideal freshwater foraging conditions and mercury concentrations in coastal nestlings were higher than during the two dry years. There was little interyear variation in mercury concentrations in nestlings from inland colonies, as parent storks from these colonies forage exclusively in freshwater habitats regardless of rainfall patterns. These results suggest that greater risk of mercury exposure to nestlings is associated with use of freshwater foraging habitats.
Pesticides and amphibian population declines in California, USA
Authors: Sparling Donald W , Fellers Gary M , McConnell Laura L
Published: March 2010

Several species of anuran amphibians have undergone drastic population declines in the western United States over the last 10 to 15 years. In California, the most severe declines are in the Sierra Mountains east of the Central Valley and downwind of the intensely agricultural San Joaquin Valley. In contrast, coastal and more northern populations across from the less agrarian Sacramento Valley are stable or declining less precipitously. In this article, we provide evidence that pesticides are instrumental in declines of these species. Using Hyla regilla as a sentinel species, we found that cholinesterase (ChE) activity in tadpoles was depressed in mountainous areas east of the Central Valley compared with sites along the coast or north of the Valley. Cholinesterase was also lower in areas where ranid population status was poor or moderate compared with areas with good ranid status. Up to 50% of the sampled population in areas with reduced ChE had detectable organophosphorus residues, with concentrations as high as 190 ppb wet weight. In addition, up to 86% of some populations had measurable endosulfan concentrations and 40% had detectable 4,4′-dichlorodiphenyldichloroethylene, 4,4′-DDT, and 2,4′-DDT residues.
Cadmium binding to a histidine-rich glycoprotein from marine mussel blood plasma: Potentiometric titration and equilibrium speciation modeling
Authors: Nair P. Satish , Robinson William E
Published: March 2010

Cadmium-binding parameters (conditional stability constants and carrying capacities) of Mytilus edulis blood plasma histidine-rich glycoprotein (HRG) were investigated by potentiometric titrations using a Cd ion-specific electrode. Titration data were applied to a single-component complexation model and expressed as Scatchard plots that were analyzed using the graphical curve peeling method and the algebraic statistical mechanical method. These sets of binding parameters, derived for the purified HRG, were subsequently entered into the geochemical speciation model MINTEQA2 and then used to simulate the experimental titration, thereby determining which set of log K and CL values best represented the titration data. The Cd binding to HRG was best described by a two-class model with log K values of 7.65 ± 0.10 and 5.41 ± 0.06 M−1 and carrying capacities of 6.0 ± 1.2 and 9.5 ± 0.4 sites/molecule, respectively. At concentrations of total Cd measured in the blood plasma of field-collected mussels (≤2 × 10−7 M), plasma Cd speciation would be dominated by the strong affinity sites of HRG (>93.5% of total Cd binds to HRG), whereas HRG itself would only be 0.05% saturated with Cd, indicating a high-capacity, apparently nonsaturable Cd transport system.
Measurement of Henry's law constant for methyltert-butyl ether using solid-phase microextraction
Authors: Bierwagen Britta G , Keller Arturo A
Published: March 2010

Increasing groundwater contamination with methyl tert-butyl ether (MTBE) requires more efficient remediation technologies. Accurate measurement of MTBE's air–water partitioning coefficient (Henry's law constant, H) is important for the design and optimization of removal efficiency for many treatment systems as well as for predicting its fate and transport. Previously published data for MTBE appear to have some unusual nonlinearity at lower temperatures (15–30°C), and a wide range of values exists for dimensionless H at 25°C, from 0.0216 to 0.1226 in the published literature. We measured H for MTBE using headspace solid-phase microextraction (SPME) and a static method that considers equilibrium partitioning in a closed system, for temperatures between 15 and 40°C. To validate our methods, we measured H for benzene, toluene, and trichloroethylene and compared our results to previously published values, with excellent agreement. The Arrhenius plot for MTBE indicates that ln(H  MBTE) = 6.85−2,900 T  −1, with T in K. At 25°C, H  MBTE = 0.0555 ± 0.0122.
Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 1. Short-term effects on soil microbiology
Authors: Elsgaard Lars , Petersen Søren O , Debosz Kasia
Published: March 2010

Linear alkylbenzene sulfonates (LAS) may occur in sewage sludge that is applied to agricultural soil, in which LAS can be inhibitory to biological activity. As a part of a broader risk assessment of LAS in the terrestrial environment, we tested the short-term effects of aqueous LAS on microbial parameters in a sandy agricultural soil that was incubated for up to 11 d. The assays included 10 microbial soil parameters: ethylene degradation; potential ammonium oxidation; potential dehydrogenase activity; β-glucosidase activity; iron reduction; the populations of cellulolytic bacteria, fungi and actinomycetes; the basal soil respiration; and the phospholipid fatty acid (PLFA) content. Except for β-glucosidase activity, basal respiration, and total PLFA content, all soil parameters were sensitive to LAS, with EC10 values in the range of less than 8 to 22 mg/kg dry weight. This probably reflected a similar mode of LAS toxicity, ascribed to cell membrane interactions, and showed that sensitivity to LAS was common for various soil microorganisms. The extracellular β-glucosidase activity was rather insensitive to LAS (EC10, 47 mg/kg dry wt), whereas the basal soil respiration was not inhibited even at 793 mg/kg dry weight. This was interpreted as a combined response of inhibited and stimulated compartments of the microbial community. The PLFA content, surprisingly, showed no decrease even at 488 mg/kg. In conclusion, LAS inhibited specific microbial activities, although this could not be deduced from the basal respiration or the total PLFA content. The lowest EC10 values for microbial soil parameters were slightly higher than the predicted no-effect concentrations recently derived for plants and soil fauna (˜5 mg/kg dry wt).
Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 3. Sublethal effects on soil invertebrates
Authors: Holmstrup Martin , Krogh Paul Henning
Published: March 2010

Sewage sludge applied to agricultural soils often contains considerable amounts of linear alkylbenzene sulfonates (LAS). Toxic effects of LAS on soil organisms should, therefore, be evaluated to ensure safe use of sewage sludge as a fertilizer. In this study, dose—response relationships for the toxicity of Na-LAS to six species of soil invertebrates (survival, reproduction, and growth) were established using a sandy, agricultural soil as test substrate. In general, toxic effects on reproduction and growth appeared when the concentration in soil exceeded 40 to 60 mg/kg. Reproduction was approximately fourfold more sensitive in earthworms and enchytraeids than in springtails and mites. It is argued that this difference in sensitivity is related to the dependency of soil pore water, which is high in the annelids but comparatively low in the arthropods.
Effects of pre- and postnatal polychlorinated biphenyl exposure on metabolic rate and thyroid hormones of white-footed mice
Authors: French John B , Voltura Mary Beth , Tomasi Thomas E
Published: March 2010

Energy budgets have proven to be a valuable tool for predicting life history from physiological data in terrestrial vertebrates, yet these concepts have not been applied to the physiological effects of contaminants. Contaminants might affect energy budgets by imposing an additional metabolic cost or by reducing the overall amount of energy taken in; either process will reduce the energy available for production (i.e., growth or reproduction). This study examined whole animal energetic effects of polychlorinated biphenyl (PCB) exposure in white-footed mice (Peromyscus leucopus). Exposure to PCBs is known to reduce concentrations of plasma thyroid hormones, and thyroid hormones exert strong control over the rate of energy metabolism in mammals. Peromyscus leucopus that were proven breeders were fed PCBs in their food at 0, 10, and 25 ppm. Through lactation, offspring were exposed to PCB from conception and were maintained on the maternal diet to adulthood. No effects were seen on energy metabolism (O2 consumption, measured in adulthood) or on growth, but there were large dose-dependent decreases in thyroid hormone concentrations, particularly T4. The apparent disparity in our data between unchanged metabolic rates and 50% reductions in T4 concentrations can be rationalized by noting that free T3 (the fraction not bound to plasma protein) in treated mice was not significantly different from controls and that metabolism is most strongly influenced by free T3. Overall, this study did not demonstrate any energetic consequences of PCB exposure in P. leucopus at dietary concentrations up to 25 ppm.
Variability in acetylcholinesterase and glutathioneS-transferase activities inChironomus ripariusmeigen deployed in situ at uncontaminated field sites
Authors: Olsen Tony , Ellerbeck Lucy , Fisher Tom , Callaghan Amanda , Crane Mark
Published: March 2010

An in situ system was used to expose fourth instar Chironomus riparius Meigen larvae for 48-h at 13 uncontaminated river sites across southeast England. Acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities were measured in individual larvae recovered from these sites. Activities of both biomarkers varied almost twofold across the sites, with statistically significant differences detectable between sites. There were no clear relationships between biomarker activities and physical or chemical characteristics measured at each site. This study shows that biomarker measurements can be used successfully in conjunction with an in situ system. However, the results of statistically significant biomarker results must be treated with caution because natural variability in responses can occur even in the absence of toxicant exposure.
Freeze concentration of ambient waters for toxicity testing
Authors: deBruyn Adrian M H , Rasmussen Joseph B
Published: March 2010

We have developed a method to concentrate aqueous samples for toxicity testing. This method relies on the phenomenon of freezing exclusion, whereby solutes are rejected from the interstices of a growing ice crystal. Tenfold freeze concentration gave excellent recoveries of inorganic and organic analytes, phenol and ZnSO4 toxicity from spiked natural waters, and toxicity of both pre- and postdischarge municipal wastewater. Simultaneous 10-fold concentration of strong mineral or humic ambient matrices did not substantially modify the expressed toxicity of phenol or ZnSO4, and it did not seem to generate spurious toxicity to the marine bioassay organism used (Vibrio fischeri). Hundredfold freeze concentration permitted the quantification of low levels of ambient toxicity in a wide variety of natural waters using a rapid, inexpensive microbioassay. Precipitation of matrix elements may limit the degree of concentration that can be achieved with highly mineralized or strongly humic waters. This approach is well suited to ambient toxicity testing, because it is nonspecific and has low potential for solvent contamination. Furthermore, the low temperatures involved minimize volatilization and degradation of organic contaminants.
Impact of sediment manipulation on the bioaccumulation of polycyclic aromatic hydrocarbons from field-contaminated and laboratory-dosed sediments by an oligochaete
Authors: Van Hoof Patricia L , Kukkonen Jussi V K , Landrum Peter F
Published: March 2010

The accumulation kinetics of polycyclic aromatic hydrocarbons (PAHs) by the freshwater oligochaete Lumbriculus variegatus were measured for field-contaminated and laboratory-dosed sediment. In addition, sediment manipulations typically used for homogenization and dosing in bioaccumulation assays were compared. Rather than an asymptotic approach to steady state, both resident and dosed PAH accumulation exhibited a peak during the 14-d assays, with steeper declines being noted for the lower-molecular-weight compounds. Lack of evidence of a peak for higher-molecular-weight PAHs may be due to slower kinetics and the short length of the assay. Relative to minimally mixed sediment, slurried sediment enhanced the accumulation of less-soluble resident PAHs, did not affect moderately soluble PAHs, and reduced the uptake of the more-soluble PAHs, fluorene and phenanthrene. Aging sediment after mixing reduced the availability of highly to moderately soluble resident PAHs but had no effect on less-soluble PAHs. A similar effect was noted for dosed PAHs, though a larger reduction in bioavailability was observed. Dosed PAH uptake clearance coefficients (ks) exceeded those of minimally mixed resident PAHs by factors of 3 to 4 for pyrene and 26 for benzo[a]pyrene. These results demonstrate that sediment manipulations and contamination history need to be considered when measuring PAH bioaccumulation.
Life-cycle effects of sediment-associated 2,4,5-trichlorophenol on two groups of the midgeChironomus ripariuswith different exposure histories
Authors: Ristola Tuna , Parker Daryn , Kukkonen Jussi V K
Published: March 2010

Effects of 2,4,5-trichlorophenol (TCP) on life-cycle traits of the midge Chironomus riparius and the ability of the midge to evolve tolerance to TCP were assessed using a reference group and a group preexposed to TCP during three generations, both originating from the same laboratory culture. F1 larvae of these groups were then exposed to nominal TCP concentrations of 51, 177, 355, and 532 μmol TCP/kg dry sediment and a control sediment in a life-cycle experiment. Most studied life-cycle traits (mortality, egg production, life span, male dry wt) were fairly insensitive to TCP, and significant effects were observed only at high (≥355 μmol/kg) concentrations. Larval development rate was variable, and in some cases it responded more readily to low TCP concentrations than other life-cycle parameters. Some of the observed responses were attributed to changes in food availability. No clear evidence of tolerance to 2,4,5-trichlorophenol was found, but the preexposed midges produced more eggs than the reference group. They also emerged earlier and at a smaller size than the reference midges. These differences between the midge groups suggest that some changes toward tolerance induction had occurred during the preexposure.
Dietary uptake and elimination of selected polychlorinated biphenyl congeners and hexachlorobenzene in earthworms
Authors: Wågman Nadja , Strandberg Bo , Tysklind Mats
Published: March 2010

Earthworms (Eisenia foetida) were given food contaminated with hexachlorobenzene (HxCBz) and 20 tetra- to heptachlorinated biphenyls (PCBs). The PCBs were selected to cover a wide range of physicochemical properties. The uptake efficiencies, uptake rate constants, and elimination rate constants in worms varied between the 20 PCBs. The uptake efficiencies were between 10 and 68%. The PCBs that were eliminated fastest contained few chlorine atoms, had more polar characteristics, and were sterically hindered. Slowest was the elimination for less polar PCBs with six or seven chlorine atoms such as the non-ortho-substituted PCB 169. Elimination half-lives varied between 6 and 25 d. The biomagnification factors (BMFs) for the PCBs and HxCBz averaged 0.1 based on lipids and 0.04 based on wet (worms) and dry (food) weight. Worm cocoons were analyzed for PCBs for the first time. The PCB pattern in the cocoons differed from the adult worms by the comparatively higher load of non-ortho PCBs. By studying congeners covering a large range of PCB physicochemical characteristics, their fate within the environmental and the factors influencing biological responses can be better understood.
Cadmium uptake by earthworms as related to the availability in the soil and the intestine
Authors: Oste Leonard A , Dolfing Jan , Ma Wei-chun , Lexmond Theo M
Published: March 2010

The free metal concentration in the soil solution is often considered a key parameter for metal uptake by and toxicity to soft-bodied soil organisms. The equilibrium partitioning theory, which assumes a relationship between the contaminant concentration in pore water and the contaminant concentration in the body tissue, can be used to describe uptake by earthworms. This theory has proved useful for organic chemicals, but its applicability is less clear for metals. In this study, the Cd concentration in soil pore water (pw) was varied by increasing the soil pH by the addition of lime (Ca(OH)2) and by adding manganese oxide (MnO2), which has a high metal binding capacity. Both lime (0.135% w/w) and MnO2 (1% w/w) decreased [Cd2+]pw by a factor of 25, while CdWorm was reduced only by a factor of 1.3 in lime-treated soils and 2.5 in MnO2-treated soils. Cadmium uptake was weakly related to the free metal concentration (R2adj = 0.66). Adding pH as an explanatory variable increased R2adj to 0.89, indicating that Cd uptake from pore water is pH dependent, which might be attributed to competition of protons and Cd at the surface of the earthworm body. However, previous earthworm experiments in reconstituted groundwater showed a conspicuously smaller pH dependency of Cd uptake. The differences in metal uptake between earthworms in lime- and MnO2-treated soils are therefore more likely to reflect the predominance of pH-independent intestinal uptake of Cd. Equilibrating the soil with a solution of 0.01 M CaCl2 and 0.1 M triethanolamine (buffered at pH 7.2), simulating the conditions prevailing in the worm intestine, yielded free Cd concentrations that were closely (R2adj = 0.83) and linearly related to the Cd concentration in the earthworm tissue.
Abnormalities in sexual development of the amphipod Gammarus pulex (L.) found below sewage treatment works
Authors: Gross Melanie Yvette , Maycock Dawn Stretton , Thorndyke Michael Charles , Morritt David , Crane Mark
Published: March 2010

Increasing numbers of widely used industrial, agricultural, and natural chemicals are known to elicit endocrine-disrupting effects in a wide range of vertebrate and invertebrate species. The objective of this study was to determine whether the sexual development of the freshwater crustacean Gammarus pulex (L.) was affected below sewage treatment works (STW) previously known to contain endocrine-disrupting chemicals in their effluent. The gonadal structure, external sexual characteristics, and size of gammarids from exposed sites were compared to those of gammarids from a reference site. No significant difference was found in the gonadal structure of males collected below two STW. However, a highly significant number of females collected from a site known to elicit high estrogenic responses in vertebrates displayed an abnormal structure of oocytes in vitellogenesis. Body size was significantly shorter and male/female size differential was significantly reduced below one of the STW. Analysis of gnathopod and genital papillae length data suggests that different allometric relationships of these organs to body size exist between sample sites.
Effects of three vertebrate hormones on the growth, development, and reproduction of the tomato moth, Lacanobia oleracea L. (Lepidoptera: Noctuidae)
Authors: Kirkbride-Smith Anne E , Bell Howard A , Edwards John P
Published: March 2010

In recent years, concern has been growing that numerous manmade chemicals entering the environment are capable of mimicking endogenous hormones in wildlife. In an attempt to define and evaluate the possible impact of endocrine-disrupting substances (EDS) on insects, three vertebrate hormones were tested for their effects on growth, development, and reproduction of the tomato moth, Lacanobia oleracea. Dietary administration of estrogen or thyroxine caused a significant increase in the length of the third, fourth, fifth, and sixth larval stadia (p < 0.001). The mean time for development of the pupa, however, was not significantly different between treatments. Relative to the control groups, a significant (p < 0.05) reduction in the mean weights of fifth- and sixth-instar larvae was also observed when larvae were exposed to estrogen or thyroxine and in pupae derived from insects exposed to thyroxine or testosterone (p < 0.001). Despite this, the number of larvae that survived to adulthood was not affected by any of the treatments; neither was the pupal sex ratio affected. However, exposure of larvae to testosterone significantly (p < 0.05) increased the number of deformed pupae. In addition, the reproductive potential of adults derived from the testosterone treatment was markedly reduced. Exposure of L. oleracea larvae to this steroid caused a highly significant (p < 0.001) decrease in egg production, coupled with a significant (p < 0.05) decrease in egg viability. The physiological effects observed in L. oleracea and their possible causes are presented in this paper, and the likely impact of EDS and their effects on terrestrial invertebrates are discussed.
Polychlorinated naphthalenes, biphenyls, dibenzo-p-dioxins, and dibenzofurans as well as polycyclic aromatic hydrocarbons and alkylphenols in sediment from the Detroit and Rouge Rivers, Michigan, USA
Authors: Kannan Kurunthachalam , Lee Kober Jamie , Kang Youn-Seok , Masunaga Shigeki , Nakanishi Junko , Ostaszewski Arthur , Giesy John P
Published: March 2010

Sediment from the upper Detroit and lower Rouge Rivers in southeastern Michigan, USA, were analyzed to examine the distribution of polychlorinated naphthalenes (PCNs), biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) as well as polycyclic aromatic hydrocarbons (PAHs) and alkylphenolic compounds such as butylphenol, octylphenol, and nonylphenol (NP). Sediments from a non–point source location in Lake Michigan were also analyzed for target compounds. Concentrations of target compounds in the upper Detroit and lower Rouge Rivers varied considerably among locations, and notable spatial variation existed. Concentrations of PCNs and PCDDs/PCDFs in sediments from the upper Detroit and lower Rouge Rivers ranged from 0.08 to 187 ng/g and 69 to 1420 pg/g dry weight, respectively. Total PCBs, PAHs, and NP concentrations ranged from 8 to 25,000, 17 to 44,000, and <10 to 60,000 ng/g dry weight, respectively. Concentrations of all target compounds except PCNs were significantly correlated with total organic carbon content of sediments. Similarly, concentrations of PCBs, PCDDs, and PCDFs were significantly correlated with each other. The distribution of organic contaminants in the upper reaches of the Detroit River and lower Rouge River suggested the presence of localized, but multiple, sources of contamination for each compound class. Conners Creek combined sewer overflow has been identified as one of the potential sources for the upper Detroit River, where the highest concentrations PCBs and PCDDs/PCDFs were found. Polycyclic aromatic hydrocarbon and NP concentrations were consistently high in sediment from the lower Rouge River. Analysis of data from selected locations suggested that PCNs contributed a greater proportion of the dioxin-like activity than PCBs and PCDDs/PCDFs contributed.
Benzo[a]pyrene and zinc solubilization by digestive fluids of benthic invertebrates—a cross-phyletic study
Authors: Mayer Lawrence M , Weston Donald P , Bock Michael J
Published: March 2010

Contaminant bioavailability via digestive exposure was examined for 18 species of marine benthic invertebrates, using incubation of digestive fluids with sediments that were spiked with either radiolabeled benzo-[a]-pyrene (BaP) or zinc. Interphyletic trends in contaminant solubilization were compared with measures of digestive biochemistry, including enzyme activities, surfactancy, pH, and fluid phase organic carbon, amino acids, and lipids. Contaminant solubilization ranged from values equal to that of a seawater control to as much as an order of magnitude higher but were lower than those obtained with commonly used chemical extractants. Digestive fluids from echinoderms and a cnidarian tended to be relatively weak, those from polychaetes and echiurans were relatively strong, and those from taxa such as sipunculans and mollusks were intermediate. These trends correlated strongly with concentrations or activities of digestive biochemicals but not with pH. These correlations are consistent with previous work on mechanisms of digestive solubilization of polycyclic aromatic hydrocarbons (PAH) and metals, though strong covariance among digestive parameters does not allow this approach to be used for identification of specific mechanism(s).
Evaluating degradation rates of chlorinated organics in groundwater using analytical models
Authors: Washington John W , Cameron Bain A
Published: March 2010

The persistence and fate of organic contaminants in the environment largely depends on their rate of degradation. Most studies of degradation rate are performed in the lab where chemical conditions can be controlled precisely. Unfortunately, literature values for lab degradation studies often are orders of magnitude higher than for field-generated studies, calling into question the relevance of lab-generated values for characterizing the persistence of organic contaminants in the environment. Complicating analysis of this ostensible disparity between lab and field degradation values, field-generated values often do not account for effects of adsorption. Modeling with a newly derived analytical solution for first-order degradation coupled with advective losses and adsorption to solve for degradation constants is insensitive to uncertainties in field properties. Application to field data shows that accounting for advection and adsorption greatly affects the value of calculated degradation constants compared to disappearance constants, which do not account for these phenomena. In fact, degradation constants, calculated using these analytical solutions and field data, are in the range reported for lab-generated data. Using these analytical solutions, for the sulfate-reducing field conditions documented for this site, perchloroethene, trichloroethene, 1,1,1-trichloroethane, 1,1-dichloroethane, and chloroethane all degraded with half-lives ranging from 5 to 115 d. Consistent with other studies of sulfate-reducing conditions, cis-1,2-dichloroethene did not chemically degrade at a measurable rate. When nonaqueous phase 1,1-dichloroethane is present, down-gradient concentrations vary in an annual sinusoidal pattern, apparently because of seasonal variation in dilution from groundwater recharge.
Accumulation of 137Cesium and 90Strontium from abiotic and biotic sources in rodents at Chornobyl, Ukraine
Authors: Chesser Ronald K. , Rodgers Brenda E , Wickliffe Jeffrey K , Gaschak Sergei , Chizhevsky Igor , Phillips Carleton J , Baker Robert J
Published: March 2010

Bank voles (Clethrionomys glareolus) and laboratory strains of house mice (Mus musculus BALB and C57BL) were relocated into enclosures in a highly contaminated area of the Red Forest near the Chornobyl (Ukraine) Reactor 4 to evaluate the uptake rates of 137Cs and 90Sr from abiotic sources. Mice were provided with uncontaminated food supplies, ensuring that uptake of radionuclides was through soil ingestion, inhalation, or water. Mice were sampled before introduction and were reanalyzed every 10 d for 137Cs uptake. Levels of 90Sr were assessed in subsamples from the native populations and in experimental animals at the termination of the study. Uptake rates in house mice were greater than those in voles for both 137Cs and 90Sr. Daily uptake rates in house mice were estimated at 2.72 × 1012 unstable atoms per gram (whole body) for 137Cs and 4.04 × 1010 unstable atoms per gram for 90Sr. Comparable rates in voles were 2.26 × 1011 unstable atoms per gram for 137Cs and 1.94 × 1010 unstable atoms per gram for 90Sr. By comparing values from voles in the enclosures to those from wild voles caught within 50 m of the enclosures, it was estimated that only 8.5% of 137Cs was incorporated from abiotic sources, leaving 91.5% being incorporated by uptake from biotic materials. The fraction of 90Sr uptake from abiotic sources was at least 66.7% (and was probably much higher). Accumulated whole-body doses during the enclosure periods were estimated as 174 mGy from intramuscular 137Cs and 68 mGy by skeletal 90Sr in house mice over 40 d and 98 mGy from 137Cs and 19 mGy from 90Sr in voles over 30 d. Thus, uptake of radionuclides from abiotic materials in the Red Forest at Chornobyl is an important source of internal contamination.
Persistence of the effects of Jet-A in a microcosm with releases from the sediment
Authors: Sandberg Randy S , Landis Wayne G
Published: March 2010

This study investigates both the methods and the multispecies and functional level effects of a release of a complex hydrocarbon mixture from sediments using a 60-d modified mixed flask culture (MFC) microcosm. Neat Jet-A was injected and mixed into the sediment with one nondosed and three dosed concentrations. Univariate and multivariate statistical and graphical techniques were used to detect patterns in the data. A slow release of the test material from the spiked sediment layer was obtained, and constituents of Jet-A were detected. Functional parameters (such as pH) were generally better at determining treatment groups than structural parameters (population densities). Analysis of the ability of the various parameters to detect treatment differences confirms that there is not one best indicator for the status of an ecological structure. Transient but statistically significant outcomes were seen at initial treatment concentrations as low as 2 μl/L. The higher concentration treatment groups could be identified as distinguished from nondosed or lower treatments at the end of the 63-d experiment. Each of the three multivariate techniques differed in their ability to distinguish treatment groups during the course of the experiment.
Life history and spatial distribution of the enchytraeid worm Cognettia sphagnetorum (Oligochaeta) in metal-polluted soil: Below-ground sink-source population dynamics?
Authors: Salminen Janne , Haimi Jari
Published: March 2010

We studied the life history, metal-avoidance behavior, spatial distribution, and population growth of enchytraeid worms (Cognettia sphagnetorum [Oligochaeta]) originating from two sites: one uncontaminated, and another patchily polluted by heavy metals. Effects of patchy soil contamination on populations were studied in microcosms. In uncontaminated soil, worms from the polluted site had lower viability and reduced growth rate as juveniles but higher growth rate as adults compared to worms from the unpolluted site. They were also smaller in size at fragmentation (reproduction). Worms from the polluted site reached a larger population size than worms from the unpolluted site. Hence, worms from the polluted site seemed to allocate more energy to reproduction, because such a strategy can be highly adaptive when living in a less-polluted patch (the source) in, on average, a highly polluted environment. The C. sphagnetorum actively avoided Cu-contaminated soil, with the response being stronger in individuals from the contaminated site. When an unpolluted patch (the source) was surrounded by a toxic environment (the sink), worms were found in the sink, either because intraspecific competition overrode the avoidance behavior or because of random walk migration. As a result, total population size in these microcosms were as high as those in totally uncontaminated microcosms. Our results indicate that avoidance behavior and increased allocation to reproduction, together with the observed dispersal pattern, can be an adaptive strategy for C. sphagnetorum in the presence of small, less-polluted patches in, on average, a hostile environment. Hence, sink–source population regulation can explain spatial distribution and survival of C. sphagnetorum in patchily polluted field soils. When such population dynamics occur, this pattern should be taken into account when population densities in the field are monitored for ecological risk-assessment procedures concerning toxicants.
Chemical and biological availability of sediment-sorbed benzo[a]pyrene and hexachlorobiphenyl
Authors: Schuler Lance J , Lydy Michael J
Published: March 2010

This study examined the chemical and biological availability of two nonpolar organic compounds, benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP), from a spiked sediment that was aged for varying amounts of time. Chemical availability was evaluated using four different solvent combinations to extract chemicals from the sediment. The extractability of BaP and HCBP from sediment using traditional solvents was then compared to the transfer efficiency (TE) of a benthic invertebrate (Lumbriculus variegatus) to relate chemical extractability to bioavailability in the organisms. Results indicated that water was the solvent that best approximated bioavailability for BaP, whereas comparisons for HCBP were inappropriate, because TE values exceeded 100%. The inability to obtain a reasonable TE estimate for HCBP was most likely due to the fact that the oligochaetes received a major portion of their uptake from interstitial water instead of ingestion of sediment particles, which invalidated an important assumption of the TE model. Overall, the results of this study indicate that exhaustive chemical extractions may be an inaccurate representation of the bioavailable fractions for some contaminants.
Multigeneration zinc acclimation and tolerance inDaphnia magna: Implications for water-quality guidelines and ecological risk assessment
Authors: Muyssen Brita T A , Janssen Colin R
Published: March 2010

Development of zinc tolerance is described for the cladoceran Daphnia magna Straus. Zinc tolerance (i.e., toxicity and deficiency) was monitored during successive generations of D. magna acclimated to different zinc concentrations. Survival, reproduction, carapax length measurements, and cellular energy allocation assessments were used as test endpoints. Special attention was paid to the consequences of zinc deficiency. The zinc acclimation concentration clearly influenced the overall fitness of the organism. After several generations of acclimation, an optimal concentration curve was observed, with an optimum zinc concentration between 300 and 450 μg/L. Zinc deficiency resulted in a lower zinc tolerance, a higher coefficient of variation for brood size, and an increased pH sensitivity. These results clearly indicate that (background) zinc concentrations present in test and culture media have to be considered in the evaluation of toxicity test results, especially when the toxicity data are used for water-quality guideline derivation and/or ecological risk assessment. Culture and test media containing very little or no zinc do not provide a basis for useful ecotoxicological data.
Comparison of different life-cycle impact assessment methods for aquatic ecotoxicity
Authors: Schulze Carsten , Jödicke Almut , Scheringer Martin , Margni Manuele , Jolliet Olivier , Hungerbühler Konrad , Matthies Michael
Published: March 2010

Human and ecotoxicity impact categories are problematic to quantify within life-cycle impact assessment (LCIA) because their local scope makes them difficult to aggregate with the traditional global-impact categories used in life-cycle assessment (LCA). For being able to assess local impacts such as toxicity, LCIA developers increasingly include fate modeling into LCA. This article follows this development by comparing different LCIA methods for aquatic ecotoxicology and by investigating the importance of fate within LCIA, the necessity of considering freshwater and seawater compartments separately, and the key degradation and intermedia transfer processes involved. The methods are compared by assessing an example study of domestic clothes washing in former West Germany. Four LCIA methods are selected and applied to four substances emitted during the washing process. The conclusion is that the consideration of environmental fate does matter and that aquatic ecotoxic impacts can differ significantly for the same substance in freshwater and in marine ecosystems. The way (bio)degradation, photolysis, volatilization, and transfer from agricultural soils are considered plays an important role as do the system boundaries chosen. This means that the LCIA methodology should remain flexible so that appropriate methods can be chosen for different applications. Fate models being developed in the environmental risk assessment of chemicals can contribute to the further improvement of LCIA methods.
Substances with estrogenic activity in effluents of sewage treatment plants in southwestern Germany. 2. Biological analysis
Authors: Körner Wolfgang , Spengler Peter , Bolz Ulrike , Schuller Winfried , Hanf Volker , Metzger Jörg W
Published: March 2010

The proliferation test with human estrogen receptor-positive MCF-7 breast cancer cells (E-Screen assay) was applied for quantitative determination of total estrogenic activity in 24-h composite effluent samples from 16 municipal and two industrial sewage treatment plants (STPs) in the state of Baden-Württemberg, southwestern Germany. The estrogenic efficacy relative to the positive control, 17β-estradiol, was between 26 and 74% (median, 48%) for the 16 municipal STPs. Estradiol equivalent concentrations (EEQs) were between 0.2 and 7.8 ng/L (median, 1.6 ng/L) and, thereby, were lower than those found in a pilot study, which revealed EEQs of greater than 10 ng/L in the effluents of two other STPs. The EEQs in 14 of the 16 effluent samples were very similar (0.9–3.3 ng/L), indicating a rather constant input of estrogenic substances via STPs into rivers. Additional activated charcoal filtration turned out to be very efficient in further eliminating estrogenic activity from effluents. The EEQs of the E-Screen assay and those calculated from the results of extensive chemical analysis using the estradiol equivalency factors determined for 13 natural and synthetic estrogenic substances were comparable for most of the effluent samples. 17β-Estradiol, 17α-ethinylestradiol, and, to a lesser extent, estrone contributed to 90% or more of the EEQ value.
Prediction of biodegradation from the atom-type electrotopological state indices
Authors: Huuskonen Jarmo
Published: March 2010

A group contribution method based on atom-type electrotopological state indices for predicting the biodegradation of a diverse set of 241 organic chemicals is presented. Multiple linear regression and artificial neural networks were used to build the models using a training set of 172 compounds, for which the approximate time for ultimate biodegradation was estimated from the results of a survey of an expert panel. Derived models were validated by using a leave-25%-out method and against two test sets of 12 and 57 chemicals not included in the training set. The squared correlation coefficient (r2) for a linear model with 15 structural parameters was 0.76 for the training set and 0.68 for the test set of 12 molecules. The model predicted correctly the biodegradation of 48 chemicals in the test set of 57 molecules, for which biodegradability was presented as rapid or slow. The use of artificial neural networks gave better prediction for both test sets when the same set of parameters was tested as inputs in neural network simulations. The predictions of rapidly biodegradable chemicals were more accurate than the predictions of slowly bio-degradable chemicals for both the regression and neural network models.
Characterization of estrogenic compounds in water samples collected from United Kingdom estuaries
Authors: Thomas Kevin V , Hurst Mark R , Matthiessen Peter , Waldock Mike J
Published: March 2010

This report describes the identification of important estrogenic compounds in surface and sediment pore-water samples collected from the Tyne and Tees estuaries (United Kingdom) through the application of toxicity identification evaluation (TIE) procedures. The Tyne and Tees estuaries represent estuaries that have been historically impacted by industrial activities and continue to receive treated domestic sewage and industrial effluent. In 1998, Dabholm Gut on the Tees received a mixture of treated and untreated effluent, while Howdon sewage treatment works (STW) discharged primary treated effluents. An estrogenically active water sample collected from Howdon STW on the Tyne was shown to contain 17β-estradiol, androsterone, and an unknown estrogenic compound(s). Most of the activity contained in a sample collected from the Dabholm Gut combined discharges on the Tees was also due to 17β-estradiol with additional activity from nonylphenol and (tentatively) bis(2-ethylhexyl)phthalate. The only sediment pore-water sample to demonstrate estrogenic activity was collected from Dabholm Gut.
Degradation of a stilbene-type fluorescent whitening agent with hypochlorite: Identification of the degradation products by capillary electrophoresis
Authors: Blanco Marcelo , Jiménez Lidia , Valverde Ismael
Published: March 2010

The E,E-(4,4′-bis[2-sulfostyryl]biphenyl) (DSBP) is a fluorescent whitening agent widely used by the textile and detergent industries to whiten fabrics. Hypochlorite used to bleach fabrics oxidizes DSBP slowly at room temperature and in a higher rate at 60°C. The ions of metals such as Fe, Cu, and Mn accelerate the process considerably. At ambient temperature, the oxidation results from cleavage of the stilbene bonds and involves the formation of various intermediates that evolve to end products. The intermediates form within minutes to hours and the end products within months. At 60°C or in presence of the previously mentioned transition metals, intermediates form within minutes and the end products within days. The end products of the oxidation are 4-sulfobenzaldehyde and 4,4′-bisaldehyde biphenyl; in the presence of excess of hypochlorite, however, the process yields their corresponding oxidized derivatives 4-sulfobenzoic acid and 4,4′- biphenyldicarboxylic acid. Despite the chlorinating ability of hypochlorite, the major degradation products formed contain no chlorine.