bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting the toxicity of metal-contaminated field sediments using interstitial concentration of metals and acid-volatile sulfide normalizations
Authors: Hansen D.J. , Berry W.J. , Boothman W.S. , Pesch C.E. , Mahony J.D. , Di Toro D.M. , Robson D.L. , Ankley G.T. , Ma D. , Yan Q. 
Published: March 2010

Abstract
We investigated the utility of interstitial water concentrations of metals and simultaneously extracted metal/acid-volatile sulfide (SEM/AVS) ratios to explain the biological availability of sediment-associated divalent metals to benthic organisms exposed in the laboratory to sediments from five saltwater and four freshwater locations in the United States, Canada, and China. The amphipod Ampelisca abdita or the polychaete Neanthes arenaceodentata were exposed to 70 sediments from the five saltwater locations, and the amphipod Hyalella azteca or the oligochaete Lumbriculus variegatus were exposed to 55 sediments from four freshwater locations in 10-d lethality tests. Sediment toxicity was not related to dry weight metals concentrations. Almost complete absence of toxicity in spiked sediments and field sediments where metals were the only known source of contamination and where interstitial water toxic units (IWTUs) were &lt;0.5 indicates that toxicity associated with sediments having SEM/AVS ratios &lt;1.0 from two saltwater locations in industrial harbors was not metals-related as these sediments contained &lt;0.5 IWTU. Metals-associated toxicity was absent in 100% of sediments from the remaining three saltwater field locations, where metals were the only known source of contamination and SEM/AVS ratios were ≤1.0. Two-thirds of 45 sediments from seven saltwater and freshwater field locations having both IWTUs &gt;0.5 and SEM/AVS ratios &lt;1.0 were toxic. Toxicity was observed less often when SEM/AVS ratios &gt;1.0 (39%) or IWTUs &gt;0.5 (55%) were used alone. The difference between the molar concentrations of SEM and AVS (SEM – AVS) can provide important insight into the extent of additional available binding capacity, the magnitude by which AVS binding has been exceeded, and, when organism response is considered, the potential magnitude of importance of other metal binding phases. For these reasons, SEM – AVS should be used instead of SEM/AVS ratios as a measure of metals availability. Over all published experiments with both metal-spiked and field sediments, SEM – AVS and IWTUs accurately (99.2%) identified absence of sediment toxicity and with less accuracy (79.1%) identified the presence of toxicity.
Relative potencies of individual polychlorinated dibenzo-p-dioxin, dibenzofuran, and biphenyl congeners and congener mixtures based on induction of cytochrome P4501A mRNA in a rainbow trout gonadal cell line (RTG-2)
Authors: Zabel Erik W. , Pollenz Richard , Peterson Richard E. 
Published: March 2010

Abstract
Cytochrome P450-catalyzed enzyme activity in cell culture was investigated as a bioassay for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents in environmental mixtures of polychlorinated dibenzo-p-dioxin (PCDD), dibenzofuran (PCDF), and biphenyl (PCB) congeners. A problem with the use of enzyme induction is that certain congeners are unable to induce P4501A enzyme activity to the same maximal level as TCDD. We sought to eliminate this problem by measuring mRNA induction rather than enzyme activity. Rainbow trout gonadal cells (RTG-2) were exposed to PCDD, PCDF, and PCB congeners and congener mixtures, and induction of cytochrome P4501A mRNA was measured. A high level of induction in cells treated with only a medium change was seen and was due to a component of the fresh medium. 2,3,7,8-Substituted PCDD and PCDF congeners and four non-ortho-substituted PCBs caused dose-related induction of P4501A mRNA. Di-ortho-substituted PCBs did not induce P450 mRNA, but three mono-ortho-substituted PCBs caused significant induction. Toxic equivalency factors determined in RTG-2 cells were generally higher than those in rainbow trout early life stages. Rainbow trout gonadal cell (RTG-2) bioassay TCDD equivalents (TEqs) for three environmental extracts were lower than those predicted by addition of individual congener TEqs, and the synthetic congener mixture acted additively.
Organic pollutants in the coastal environment off San Diego, California. 2. Petrogenic and biogenic sources of aliphatic hydrocarbons
Authors: Tran Kim , Yu Charlie C , Zeng Eddy Y 
Published: March 2010

Abstract
The results from the measurements of aliphatic hydrocarbons suggest that hydrocarbons in the Point Loma Wastewater Treatment Plant (PLWTP) effluents are mainly petroleum derived; those in the Tijuana River runoff have largely originated from terrestrial plants with visible petroleum contamination; and those in the sea surface microlayer, sediment traps, and sediments at various coastal locations off San Diego have mostly resulted from biogenic contributions with enhanced microbial products in the summer season. Rainfall in the winter season appeared to amplify the inputs from terrestrial higher plants to the coastal areas. The PLWTP discharged approximately 3.85 metric tons of n-alkanes (C10-C35) in 1994, well below the level (136 metric tons) estimated in 1979. The input of aliphatic hydrocarbons from the Tijuana River was about 0.101 metric tons in 1994. Diffusion, solubilization, evaporation, and microbial degradation seemed partially responsible for the difference in the concentrations and compositions of aliphatic hydrocarbons in different sample media, although the relative importance of each mechanism cannot be readily discerned from the available data. The results from analyses of aliphatic hydrocarbon compositional indices are generally consistent with those of polycyclic aromatic hydrocarbons.
Similarity analysis of PAH and PCB bioaccumulation patterns in sediment-exposedChironomus tentanslarvae
Authors: Wood Lindsey W , O'Keefe Patrick , Bush Brian 
Published: March 2010

AbstractLarvae of the aquatic insect Chironomus tentans (Insecta: Diptera: Chironomidae) were exposed at the third or fourth instar stage to sediments collected near the outfalls of two aluminum foundries and an aluminum fabrication plant. Biota and sediment bioaccumulation factors (BFs), based on wet tissue weights and dry sediment weights, ranged from 0.07 to 0.27 for polycyclic aromatic hydrocarbons (PAHs) and from 0.22 to 1.42 for polychlorinated biphenyls (PCBs). A higher rate of metabolism of PAHs compared with PCBs could explain the differences in BF values for the two groups of chemicals. It was found, using community similarity procedures from the field of ecology, that the congener patterns for PAHs and PCBs bioaccumulated by the larvae differed from the pattern of the same compounds in the sediments to which they were exposed. Affinity analysis indicated that the larvae favored the higher molecular weight PAH and PCB congeners. Preferential ingestion of sediments with defined particle size ranges, metabolism, and octanol/water partition coefficients (log Kow) are factors that may have influenced the bioaccumulation patterns. However, no single factor could adequately account for the differences between the larval and sediment patterns.
Effect of application solvents on heterotrophic and nitrifying populations in soil microcosms
Authors: Miller Jerry L , Sardo Michael A , Thompson Thomas L , Miller Raina M 
Published: March 2010

Abstract
Agricultural practices may cause contamination of soil and ground water with a combination of organic compounds (pesticides and fuel) and nitrogen fertilizers. In coupled microcosm studies that monitored the mineralization of naphthalene and the nitrification of ammonia, it was observed that the solvent (dichloromethane) used to apply naphthalene to the soil inhibited nitrification, although there was no effect on naphthalene mineralization. Further studies were performed with a series of application solvents: methanol, acetonitrile, trichloromethane, and dichloromethane. Soil and solvent were allowed to equilibrate with ambient air for various times before capping and incubation of microcosms. Results indicated that dichloromethane equilibrated for 5 mins inhibited nitrification for at least 3 weeks relative to the control (water). Acetonitrile and trichloromethane similarly inhibited nitrification. Methanol and dichloromethane equilibrated for 60 mins also significantly delayed nitrification, although to a lesser extent. Inhibition of nitrification was not permanent, and nitrification activity was eventually restored in all systems tested. None of the solvents inhibited mineralization of the added carbon source. These results indicate that special care must be taken to ensure that applications solvents do not affect the activity of sensitive microbial populations, such as the nitrifiers, that may be part of a study.
Laboratory assay of sediment phytotoxicity using the macrophyte Vallisneria americana
Authors: Biernacki Maciej , Lovett-Doust Jon , Lovett-Doust Lesley 
Published: March 2010

Abstract
In contrast to their ecological importance, submersed rooted macrophytes have been overlooked in environmental science. Presently, the array of standard phytotoxic bioassays includes only one free-floating vascular macrophyte (Lemna) and several algal species. A short-term and inexpensive assay was studied for feasibility in evaluating sediment quality. Cloned ramets of the macrophyte Vallisneria americana were used to test phytotoxicity of sediments collected at different locations in the Detroit River. Ramets were planted in sediment samples and placed in greenhouse aquaria. After a week of exposure, ramets of V. americana were destructively sampled and preserved. The leaf and root surfaces areas were determined, and plant biomass was recorded for each ramet. An index of the leaf-to-root surface area ratio was a reliable predictor of sediment phytotoxicity; the ratio of leaf-to-root mass was also useful but proved less consistent. Ramets grown in sediments that were relatively less contaminated with organic compounds had lower values of the leaf-to-root surface area ratio, while plants grown in more contaminated sediments had greater values. Results of analyses of variance indicated that the index of leaf-to-root surface area ratio responded to sediment quality but was not significantly affected by either variation in plant genotype or interaction between sediment and plant genotype. There was a significant correlation (p &lt; 0.001) between rank-ordered results of the present greenhouse study and results of leaf-to-root surface area ratios for plants previously surveyed in the field.
Interlaboratory comparison of a method to evaluate the effects of chemicals on fish growth
Authors: Mallett M J , Grandy N J , Lacey R F 
Published: March 2010

Abstract
A protocol for the evaluation of chemicals on the growth rate of juvenile rainbow trout (Oncorhynchus mykiss Walbaum) over a 28-day period has been evaluated by comparison of the test results obtained by 15 laboratories from seven countries in the European Union. Two test substances were used, 3,4-dichloroaniline (DCA) and linear alkylbenzene sulfonate (LAS). Fourteen test results were received for DCA and seven for LAS. The data were analyzed in two ways: the evaluation of the lowest observed effect concentrations (LOECs), and regression analysis to estimate the concentration of the substance causing a 25% reduction in growth relative to the controls (EC25). The latter method clearly provided a number of advantages over estimation of LOECs. These included less dependence of the result upon the spacing between exposure concentrations and upon the arbitrary choice of level of statistical significance. In addition it was possible to estimate an EC25 for more data sets than was possible for LOEC estimation. The sensitivity of the test was comparable with other chronic tests (Daphnia juvenile production and fathead minnow early life stage tests) for DCA and LAS. For DCA the overall mean EC25 was 223 μg/L the EC25s found by individual laboratories ranged from 100 to 390 μg/L. For LAS the EC25 ranged from 1,220 to 2,810 μg/L.
Results of zinc deprivation in daphnid culture
Authors: Caffrey Paula Barone , Keating Kathleen Irwin 
Published: March 2010

Abstract
Daphnia pulex Leydig (Cladocera), reared in circumstances of strictly controlled trace element exposure, were deprived of zinc. When zinc was withheld from both their liquid medium and solid (algal) food, D. pulex survived for more than 20 consecutive generations before the line ceased reproduction entirely. Through these generations zinc deprivation resulted in a somewhat irregular, but continuing, shortening of life span, a decrease in fecundity (both progeny per brood and number of broods were affected), and a loss of cuticle integrity. A distinct pattern of response was observed during the gradual, multigenerational decline of the animal line. The decline can be separated into three stages: initial (first five), minimal, but steady, increase in overt damage; intermediate (sixth through 19th), varying degrees of damage with apparent severity showing a distinct alternation from generation to generation; and final (last three generations), limited reproduction with ultimate elimination of the animal line by a total absence of reproduction in generation 23.
Effects of bacterial inoculation and nonionic surfactants on degradation of polycyclic aromatic hydrocarbons in soil
Authors: Madsen Torben , Kristensen Preben 
Published: March 2010

AbstractThe aim of the study was to examine the effects of introduced bacteria and nonionic surfactants on the degradation of polycyclic aromatic hydrocarbons (PAHs) in soil. Mineralization experiments were conducted with freshly added [14C]phenanthrene or [14C]pyrene, whereas other experiments focused on the degradation of selected PAHs present in a coal tar-contaminated soil. Inoculation of soil samples with phenanthrene-utilizing bacteria stimulated the mineralization of [14C]phenanthrene. This effect, however, was most notable in soil with a low indigenous potential for PAH degradation, and a large inoculum was apparently required to establish phenanthrene mineralization in the soil. Addition of alcohol ethoxylate and glycoside surfactants to soil samples enhanced the mineralization of [14C]phenanthrene and [14C]pyrene. The nonionic surfactants also enhanced the degradation of contaminant PAHs that were present in the soil coal tar. As an example, pyrene, benzo[b,j,k]fluoranthene, and benzo[a]pyrene were resistant to degradation in the absence of surfactants, whereas significant degradation of these PAHs was observed when surfactants were added. The surfactant-related enhancement of the degradation of PAH contaminants was less convincing when a rapidly degradable glycoside surfactant was used. This suggests that surfactants that are mineralized at moderate rates may be more applicable for increasing the availability of PAHs in soil.
The relative sensitivity of chicken embryos to yolk- or air-cell-injected 2,3,7,8-tetrachlorodibenzo-p-dioxin
Authors: Henshel Diane S , Hehn Brent , Wagey Ravenska , Vo Mylinh , Steeves John D 
Published: March 2010

Abstract
We compared the relative sensitivity of chicken embryos exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) injected either into the yolk or into the air cell. The TCDD was injected at the start of incubation (embryonic day 0) and the embryos were sacrificed at multiple times during embryonic development. A subset of embryos were allowed to hatch undisturbed. The chick embryo was significantly more sensitive to TCDD when injected into the yolk than when injected into the air cell. The resultant median lethal dose (LD50) (122 pg/g egg, determined by probit analysis; 146 pg/g egg determined by interpolation) was 60% lower than the LD50 (297 pg/g egg by probit; 255 pg/g egg determined by interpolation) for air-cell-injected TCDD. A significant decrease in hatch weight of embryos exposed to high concentrations of TCDD compared to controls occurred, and this decrease was even more pronounced at a lower concentration in the yolk-injected birds. Interestingly, during the period of embryonic days 11 through 15, the mean weight of the yolk-injected embryos was smaller than the mean weight of the air-cell-injected embryos. This difference was not noticably evident just before or just after this developmental period. Embryos exposed to high concentrations of TCDD injected into either the yolk or the air cell tended to die within the first 2 weeks of incubation. A number of TCDD-exposed embryos survived the entire 21-d incubation period, but only air-cell-injected embryos were able to hatch successfully. Because the injection site varies in studies reported by different laboratories, the relative sensitivity must be considered when comparing results from different studies.
A spreadsheet program for estimating low toxic effects
Authors: Caux Pierre-Yves , Moore Dwayne R J 
Published: March 2010

Abstract
A Mcrosoftt® Excel v. 5.0 spreadsheet program for estimating low toxic effects is described using an example data set consisting of herbicide effects on corn germination. Users are guided through each step in the program. Five model equations are illustrated in both their mathematical and spreadsheet forms and statistical procedures are described.
High induction of cytochrome p4501a activity without changes in retinoid and thyroid hormone levels in flounder (Platichthys flesus) exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin
Authors: Besselink H T , van Santen E , Vorstman W , Vethaak A D , Koeman J H , Brouwer A 
Published: March 2010

Abstract
Oal dosesof 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were administered twice within 7 d (total concentration 0.01, 0.1, 1, 10, or 100 μg TCDD/kg body weight) to flounder (Platichthys flesus). After 10 d of exposure, flounder were sacrificed, and the effects of TCDD exposure on hepatic microsomal total cytochrome P450 content, 7-ethoxyresorufin-O-deethylase (EROD) activity, and glutathione-S-transferase activity were examined. In addition, plasma and hepatic retinoid and plasma thyroid hormone levels were analyzed. Overall a good correlation existed between the dose and liver concentrations of TCDD. However, only 0.75% of the total dose of TCDD was retained in the flounder liver. The TCDD caused a dose-related, statistically significant induction of the hepatic microsomal total cytochrome P450 content (4.4-fold; p &lt; 0.001) and associated EROD activity (27-fold; p &lt; 0.001), without obvious changes in body weight, liver weight, and condition factor. Total glutathione-S-transferase activity was not induced in livers of flounder exposed to TCDD. No TCDD-induced changes in liver retinoid, plasma retinol, and plasma thyroid hormone parameters were observed. These results indicate that the flounder is an aryl hydrocarbon (Ah) receptor-responsive species with respect to CYP1A induction but not with respect to other mammalian Ah receptor-associated responses.
Influence of body fat on trifluralin toxicokinetics in rainbow trout (Oncorhynchus mykiss)
Authors: Schultz Irvin R , Hayton William L 
Published: March 2010

Abstract
We previously characterized the toxicokinetics of trifluralin (TF) in rainbow trout (Oncorhynchus mykiss) and found a large steady-state volume of distribution (Vss) that was attributed to a large, poorly perfused peripheral storage compartment. Because adipose tissue was expected to be an important peripheral storage tissue for this lipophilic herbicide, we studied its toxicokinetics in trout that differed in body fat content. Large, hatchery-reared rainbow trout and adult summer-run steelhead trout were fitted with an aortic cannula and given a 1-mg/kg dose of TF. The steelhead were studied approximately 3 weeks prior to spawning and after a 9-month fasting period. The total lipid content of the steelhead after removal of the reproductive organs averaged 1.2% of body weight, whereas that of the hatchery trout was 8%. Toxicokinetic analysis of the plasma concentration-time profile using a three-compartment model found the Vss in steelhead to be reduced significantly (p &lt; 0.01) compared with the hatchery trout (1.3 vs. 5.7 L/kg). Other parameters that differed were the maximum plasma concentration, which was higher in steelhead (p &lt; 0.05), and the elimination t1/2,β and mean residence time, which were reduced (p &lt; 0.05) in steelhead. Although several physiological factors are probably involved, examination of the relationship between Vss and lipid content supported the hypothesis that the distribution of TF in trout was largely influenced by the lipid content of the fish.
The effects of hexachlorobenzene on mink in the Canadian environment: An ecological risk asssessment
Authors: Moore Dwayne R J , Breton Roger L , Lloyd Karen 
Published: March 2010

Abstract
Hexachlorobenzene (HCB) is a persistent substance that accumulates in tissues and biomagnifies up the food chain suggesting that biota at higher trophic levels (e.g., predatory birds and piscivorous mammals) are at the greatest risk of exposure. Although widespread, the highest levels of HCB in Canada are found in the Great Lakes and connecting channels. Because mink (Mustela vison) are piscivorous mammals known to be particularly sensitive to the effects of organochlorine substances, we assessed whether mink populations in the Great Lakes area are experiencing adverse effects as a result of exposure to HCB. A deterministic, deliberately hyperconservative analysis indicated that recent levels of HCB in air, water, and aquatic organisms are unlikely to pose a significant risk to mink living near Lakes St. Clair, Erie and Superior. The hazard quotients for the St. Clair River area near Sarnia and Lake Ontario, however, indicated potential risks. We conducted Monte Carlo simulations to estimate the probability that mink exposed to HCB in these areas are experiencing reproductive impairment. The results of these analyses indicate: (1) a moderate to high probability that mink in the St. Clair River area are experiencing 5 to 20% declines in reproductive success due to HCB exposure, and (2) a low probability (&lt;15%) that mink near Lake Ontario are experiencing even modest declines in reproductive fecundity (&gt;5%).
A reformulated, reconstituted water for testing the freshwater amphipod, Hyalella azteca
Authors: Smith Mark E , Lazorchak James M , Herrin Lori E , Brewer-Swartz Sandra , Thoeny William T 
Published: March 2010

Abstract
Toxicity testing with the freshwater amphipod, Hyalella azteca, has routinely been conducted using nonstandard waters. Four waters were tested for acceptability for aqueous reference toxicant testing with H. azteca. These included three formulated (standardized) waters: moderately hard reconstituted water (MHRW), reformulated moderately hard reconstituted water (RMHRW), and 25% dilute mineral water (DMW). The water used for comparison was a nonstandard, in-house culture water mixture of well water and dechlorinated tap water, diluted with Super-Q® deionized water to a hardness of 100 mg/L, as CaCO3 (LL/SQ). Control survival was less than the 90% minimum control survival criteria in all tests with MHRW. Two of five tests with DMW also failed to pass the minimum control survival criteria. All five tests with the RMHRW passed the control survival criteria. The mean 50% lethal concentration (LC50) for the tests in RMHRW was 320 mg/L KCl, with a coefficient of variation of 8.5%. Concurrent tests with the in-house water yielded control survival greater than 90% and a mean LC50 of 216 mg/L KCl with a coefficient of variation of 13.4%. Tests in an interlaboratory study yielded similar results. Whole-sediment toxicity tests conducted using RMHRW as the overlying water routinely exceed the 80% minimum survival criteria in the control and reference sediments. The failure of MHRW and DMW to produce acceptable results, as well as the inability of other laboratories to produce LL/SQ, makes RMHRW the best candidate for a standard water for H. azteca testing.