bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic toxicity of waterborne thiocyanate to the fathead minnow (pimephales promelas): A partial life-cycle study
Authors: Lanno Roman P. , Dixon D. George
Published: March 2010

Juvenile fathead minnows (Pimephales promelas) were exposed to thiocyanate (SCN−) concentrations of 0, 1.1, 7.3, 16.6, or 32.6 mg/L for 124 d while monitoring growth, physiological, reproductive, and histological parameters. The NOEC for decreased egg production, increased time to first spawn, and development of overt goiter was 1.1 mg/L, whereas the LOEC for these parameters was 7.3 mg/L. Histological changes in thyroidal tissue were the most sensitive parameter observed, with an LOEC of 1.1 mg/L. Fish exposed to 16.6 or 32.6 mg SCN−/L neither completed development of secondary sexual characteristics nor spawned. The LOEC for decreased growth and hematocrit was 32.6 mg/L. SCN− accumulated in the plasma of fish exposed to 16.6 and 32.6 mg/L, with BCFs of 2.7 and 13.8, respectively. Development and mortality of embryos and larvae to 3 d post-hatch were also monitored in eggs spawned by adults exposed to 0 or 1.1 mg SCN−1/L and subsequently incubated and hatched at 0, 1.1, 7.3, 16.6, or 32.6 mg/L. Eggs spawned by adults exposed to 1.1 mg SCN−1/L exhibited increased percentage of eyeup and hatch, while decreasing time to hatch and mortality. There were no effects of SCN− concentration during incubation on egg viability. After the 124-d exposure, adults were transferred to SCN−-free water for 30 d. Insufficient numbers of adults were available from groups exposed to 32.6 mg/L to be included in the recovery study. Eggs were spawned by all groups during the recovery period, regardless of the SCN− preexposure level, although time to first spawn increased with preexposure concentration.
Feeding selectivity and assimilation of PAH and PCB in Diporeia spp.
Authors: Harkey Gail A. , Lydy Michael J. , Kukkonen Jussi , Landrum Peter F.
Published: March 2010

A series of experiments were conducted to estimate assimilation efficiencies of two hydrophobic organic contaminants and the influence of particle sizes on the selective sediment ingester, Diporeia spp. Florissant soil was divided into particle-size fractions consisting of 0 to 63 μm, 0 to 20 μm, and 20 to 63 μm and dosed with radiolabeled 2,2′,4,4′,5,5′-hexachlorobiphenyl (HCBP) and/or benzo[a]pyrene (BaP) to which animals were exposed for individual assays. At the end of timed exposure intervals, individual Diporeia and any fecal pellets they produced were removed from the sediment and analyzed for contaminant content. Assimilation efficiency was estimated via a selectivity index based on organic carbon. Assimilation efficiency of BaP (5.6–32.7%) was comparable to previous studies. However, HCBP did not correlate with organic carbon over a range of particle sizes. Accumulation of both contaminants was greatest when animals were exposed to the 20- to 63-μm size fraction, suggesting that Diporeia selectively fed within this particle-size range. Accumulation of HCBP was consistently greater than BaP in all dual-labeled assays, suggesting a greater bioavailability of the PCB to Diporeia. Sediment analysis indicated that BaP and HCBP were associated with different particle-size fractions possessing different amounts of organic carbon, with BaP having the greater tendency to associate with TOC.
Comparative cytotoxicity of chlorophenols to cultured fish cells
Authors: Saito Hotaka , Shigeoka Tadayoshi
Published: March 2010

In vitro cytotoxicity of chlorophenols to Cyprinus carpio brain (CCB) cells derived from carp and Oryzias latipes fin (OLF 136) cells derived from medaka was examined with the neutral red (3 amino 7 dimethylamino 2-methylphenazine hydrochloride) incorporation assay Results were compared with previous cytotoxicity data of chlorophenols to goldfish (Carassius auratus) scale (GFS) cells derived from the goldfish There were excellent correlations between the 24 h NR50 values of chlorophenols toward the three kinds of cells (r2 > 0 94)
Spatial and temporal variability in metal bioavailability and toxicity of sediment from hamilton harbour, lake ontario
Authors: Krantzberg Gail
Published: March 2010

Trace metals in sediment from nearshore urban and industrialized centres of the Great Lakes are frequently at concentrations well above geological background values Total metal content in sediment, however, is a weak predictor of sediment toxicity This study examined the bioavailability of metals from Hamilton Harbour in Lake Ontario and considered variability in metal forms on a temporal basis Sediment from regions within Hamilton Harbour is highly contaminated with metals, nevertheless, not all metal contaminated sites were toxic to test organisms Most sediment did elicit sublethal and/or lethal responses in bioassay organisms Metal bioavailability, as measured by weak acid extractions, metal bioaccumulation by fathead minnows, and sediment toxicity, was greater in sediment collected in the fall as compared to sediment collected in the spring Results of analyses of tissue residues in test organisms and the reduced toxicity observed in sediment collected from some stations in the spring as compared to the fall implicate trace metals and sediment oxygen demand as contributing to sediment toxicity The suitability for colonization by benthic invertebrates of sediment in some areas of Hamilton Harbour appears to be limited by both contaminants and high sediment oxygen demand Improving the oxygen regime of the harbour should result in improvements in the benthic invertebrate community directly, by providing a suitable oxygen regime for organisms less tolerant of temporal anoxia and indirectly by decreasing metal bioavailability, possibly through the co precipitation of trace metals with iron and manganese hydroxides
Factors affecting chemical and biological reduction of hexavalent chromium in soil
Authors: Losi M.E. , Amrhein C. , Frankenberger W.T.
Published: March 2010

Hexavalent chromium [Cr(VI)] is a common environmental pollutant that is mobile in soils and is a known mutagen The trivalent form [Cr(III)] has no known mutagenic properties and is highly insoluble and immobile above pH 5 5 Reduction to the trivalent state thus represents an effective mechanism for detoxification and immobilization of Cr(VI) in soil/water systems In this study, we conducted experiments to examine various parameters involving aerobic reduction of Cr(VI) in a field soil We found that organic matter content, bioactivity, and oxygen status were important factors Under optimum conditions, the soil reduced 96% of added Cr(VI) under aerobic, field moist conditions The pH of the system was shown to have little effect Both biological and nonbiological processes were influential, and, of 20 chromate resistant bacterial cultures isolated from soils, 9 were found to actively reduce Cr(VI) to Cr(III) in liquid media Our study suggests that organic amended soils can readily reduce Cr(VI) and could promote excellent removal efficiency either as a primary treatment technique, or in conjunction with bioreactor type wastewater treatment systems
Mutagenicity screening of reaction products from the enzyme-catalyzed oxidation of phenolic pollutants
Authors: Massey I. Joanna , Aitken Michael D. , Ball Louise M. , Heck Phillip E.
Published: March 2010

Phenol-oxidizing enzymes such as peroxidases, laccases, and mushroom polyphenol oxidase are capable of catalyzing the oxidation of a wide range of phenolic pollutants. Although the use of these enzymes in waste-treatment applications has been proposed by a number of investigators, little information exists on the toxicological characteristics of the oxidation products. The enzymes chloroperoxidase, horseradish peroxidase, lignin peroxidase, and mushroom polyphenol oxidase were used in this study to catalyze the oxidation of phenol, several mono-substituted phenols, and pentachlorophenol. Seventeen reaction mixtures representing selected combinations of enzyme and parent phenol were subjected to mutagenicity screening using the Ames Salmonella typhimurium plate incorporation assay; five selected mixtures were also incubated with the S9 microsomal preparation to detect the possible presence of promutagens. The majority of reaction mixtures tested were not directly mutagenic, and none of those tested with S9 gave a positive response. Such lack of mutagenicity of enzymatic oxidation products provides encouragement for establishing the feasibility of enzyme-catalyzed oxidation as a waste-treatment process. The only positive responses were obtained with reaction products from the lignin peroxidase–catalyzed oxidation of 2-nitrophenol and 4-nitrophenol. Clear positive responses were observed when strain TA100 was incubated with 2-nitrophenol reaction-product mixtures, and when strain TA98 was incubated with the 4-nitrophenol reaction mixture. Additionally, 2,4-dinitrophenol was identified as a reaction product from 4-nitrophenol, and preliminary evidence indicates that both 2,4- and 2,6-dinitrophenol are produced from the oxidation of 2-nitrophenol. Possible mechanisms by which these nitration reactions occur are discussed.
Toxicological significance of non-, mono- and di-ortho-substituted polychlorinated biphenyls in oysters from galveston and tampa bays
Authors: Sericano Jose L. , Wade Terry L. , Brooks James M. , Safe Stephen H.
Published: March 2010

Concentrations of non ortho (77, 126, and 169), mono-ortho (105 and 118) and di-ortho (128 and 138) substituted PCB congeners were measured in oysters from Galveston and Tampa bays, and reported toxic equivalent factors were used to assess their toxicity Most of the relative toxicity encountered in the oysters analyzed during this study was due to the presence of planar non-ortho-PCBs (53 8–94 3%), particularly congener 126 In contrast, the contribution of di-ortho-substituted PCB congeners to the total relative toxicity of the samples was negligible (<1%) On average, the contribution of each of these non, mono, and di ortho substituted PCB congeners to the total toxicity encountered in oysters from Galveston and Tampa bays were 126 > 118 ≥ 169 ≥ 105 > 77 » 138 > 128 and 126 > 118 > 169 ≥ 77 > 105 » 138 > 128, respectively Based on the reported lower clearance rates of non ortho and mono ortho-substituted PCB congeners compared to other congeners within the same chlorination level, contaminated oysters that are depurated in clean environments will lower their total PCB concentrations, but their original toxicity may not be proportionally reduced
The effect of exposure to 1,2,4,5-tetrachlorobenzene and the relationship between toxicant and oxygen uptake in rainbow trout (Oncorhynchus mykiss) during exercise
Authors: Brauner C.J. , Randall D.J. , Neuman J.F. , Thurston R.V.
Published: March 2010

These studies were designed to investigate the relationship between the initial uptake of a model toxicant, 1,2,4,5-tetrachlorobenzene (TCB), and the rate of oxygen consumption (MO2) in trout during exercise. There was no effect of environmental TCB concentrations ([TCB]) on the MO2 of resting or exercising adult rainbow trout, and body accumulations of the toxicant did not affect the maximal aerobic swimming velocity attained by juvenile rainbow trout. Rainbow trout were exposed to TCB for 1 h while swimming at different velocities and the [TCB] was measured in plasma and 11 other tissues. Tissue TCB concentrations were found to be extremely variable despite similar exposure conditions, likely due to differences in tissue lipid content. No one tissue was representative of body burden, but tissue TCB delivery appears to be directly related to the [TCB] in the plasma because at different swimming velocities the plasma:tissue TCB ratios remained constant despite regional changes in blood flow. After 2 h of TCB exposure, [TCB] in the plasma was equal to whole-body [TCB]; however, this relationship broke down after 6 h. Thus, whole-body TCB concentrations can only be obtained through direct measurement. There was a highly significant relationship (r2 = 0.79) between MO2 and TCB uptake rate during initial toxicant exposure in adult rainbow trout forced to swim over a large proportion of its aerobic potential. Thus, toxicant uptake in fish may be estimated based upon MO2, which can be measured or can be obtained from the literature.
Scaling spatial predictability: An approach to multi-resolution modeling
Authors: Maxwell Thomas , Costanza Robert
Published: March 2010

We have investigated the dependence of spatial predictability, a statistical measure of the reduction in uncertainty about one spatial variable that can be gained by knowledge of another, on the spatial resolution (Rs) of the variables. While increasing resolution provides more descriptive information about the patterns in data, it also increases the difficulty of accurately modeling those patterns. By examining the variation of spatial predictability with Rs in a number of case studies, we have proposed the existence of an “optimal” Rs for specific studies, which balances these two factors. We analyzed land-use data by resampling map data sets at several different spatial resolutions and measuring predictability at each. Spatial auto-predictability (Pa) is the reduction in uncertainty about the state of a cell in a map given knowledge of the state of adjacent cells in that map, and spatial cross-predictability (Pc) is the reduction in uncertainty about the state of a cell in a map given knowledge of the state of corresponding cells in other maps. The Pa is a measure of the internal pattern in the data, whereas Pc is a measure of the ability of some “model” to represent the transition from one map to another. We found a strong linear relationship between the log of Pd and the log of Rs (measured as the number of cells per square kilometer). While Pa generally increases with increasing Rs (because more information is being included), Pc generally falls or remains stable (because it is easier to model aggregate results than fine-grained ones). Thus, one can define an “optimal” Rs a particular modeling problem that balances the benefit in terms of increasing data predictability (measured by Pa) as one increases resolution, with the cost of decreasing facility of modeling the temporal dynamics (measured by Pc).
Chemical characterization of sediments and pore water from the upper Clark Fork river and milltown reservoir, Montana
Authors: Brumbaugb W.G. , Ingersoll C.G. , Kemble N.E. , May T.W. , Zajicek J.L.
Published: March 2010

The upper Clark Fork River basin in western Montana is widely contaminated by metals from past mining, milling, and smelting activities As part of a comprehensive ecological risk assessment for the upper Clark Fork River, we measured physical and chemical characteristics of surficial sediment samples that were collected from depositional zones for subsequent toxicity evaluations Sampling stations included five locations along the upper 200 km of the river, six locations in or near Milltown Reservoir (about 205 km from the river origin), and two tributary reference sites Concentrations of As, Cd, Cu, Mn, Pb, and Zn decreased from the upper stations to the downstream stations in the Clark Fork River but then increased in all Milltown Reservoir stations to levels similar to uppermost river stations Large percentages (50 to 90%) of the total Cd, Cu, Pb, and Zn were extractable by dilute (3 n) HCl for all samples Copper and zinc accounted for greater than 95% of extractable metals on a molar basis Acid-volatile sulfide (AVS) concentrations were typically moderate (0 6 to 23 μmol/g) in grab sediment samples and appeared to regulate dissolved (filterable) concentrations of Cd, Cu, and Zn in sediment pore waters Acid volatile sulfide is important in controlling metal solubility in the depositional areas of the Clark Fork River and should be monitored in any future studies Spatial variability within a sampling station was high for Cu, Zn, and AVS, therefore, the potential for toxicity to sediment dwelling organisms may be highly localized
Modeling toxicity due to intermittent exposure of rainbow trout and common shiners to monochloramine
Authors: Meyer Joseph S. , Gulley David D. , Goodrich Mark S. , Szmania Donald C. , Brooks Arthur S.
Published: March 2010

We evaluated the ability of three mathematical models to predict toxicity to common shiners and rainbow trout during intermittent (pulsed) exposures to monochloramine, based on data from continuous-exposure toxicity tests. If a power term for the exposure-water concentration was included in the models, a concentration × time (Cxt) model and the Mancini uptake-depuration model predicted pulse LC50s to within ±50% of the observed pulse LC50s, for the first four pulses in toxicity tests with 2-h pulse/22-h recovery cycles. Beyond the fourth pulse cycle, though, the pulse LC50s predicted using the Cxt model appeared to diverge considerably from the trend of the experimental pulse LC50s, partly because this model does not predict an incipient lethal level (CILL) for either continuous or intermittent exposures. The Mancini model predicted the CILL moderately well in the common shiner intermittent-exposure test but not in the rainbow trout intermittent-exposure test. The Breck three-dimensional damage-repair model did not predict pulse LC50 or CILL values as well as did the other two models, probably because not enough partial-mortality data were available to parameterize the model adequately. Although the underlying processes appear to be more complex than what these simple models assume, the models may still be adequate for use in regulating a few pulse discharges of monochloramine.
Multivariate QSBR modeling of biodehalogenation half-lives of halogenated aliphatic hydrocarbons
Authors: Eriksson Lennart , Jonsson Jörgen , Tysklind Mats
Published: March 2010

Multivariate quantitative structure-biodegradability relationships (QSBRs) were developed for a series of 20 halogenated aliphatic hydrocarbons investigated for their microbial biodehalogenation (expressed as half-lives). These QSBRs are based on a battery of quantum-chemical descriptors and the use of the multivariate data analytical techniques principal component analysis (PCA) and partial least-squares projections to latent structures (PLS). The developed models are introduced and discussed from a multivariate data analytical perspective, and much emphasis is placed on the elucidation of the predictive significance of the developed relationships. It is shown that multivariate QSBRs can be formulated for three sets of microorganisms and compounds. These QSBRs can be used to predict biodehalogenation properties for yet untested compounds.
Effects of brine addition on effluent toxicity and marine toxicity identification evaluation (TIE) manipulations
Authors: Ho Kay T. , Mitchell Kyran , Zappala Matthew , Burgess Robert M.
Published: March 2010

Little information is available concerning the effect of salinity adjustment on effluent storage and toxicity identification evaluation (TIE) performance. These factors are important for accurate assessments of potential toxicity to marine organisms. The objective of this study was to determine (a) the effect of salinity adjustment (to 30 ppt), using hypersaline brine (100 ppt), on the toxicity of effluents stored up to 40 d, and (b) to determine the effect of salinity adjustment on TIE manipulations. Changes in effluent toxicity over time were examined by using a municipal and an industrial effluent. A toxicity time series was performed for 16 d for the industrial effluent and 40 d for the municipal effluent. Toxicity was measured with modified 48-h acute Mysidopsis bahia and Menidia beryllina tests Results indicate that, compared to day 0 test results, effluent stored with brine had fewer significant changes in toxicity than did effluent stored without brine To determine the effects of brine addition on TIE manipulations, we conducted a series of manipulations in which one aliquot of an effluent had brine added prior to the TIE manipulations and the other aliquot had brine added after the TIE manipulation The manipulations conducted were EDTA addition, sodium thiosulfate addition, C18 extraction, aeration, filtration, and graduated pH manipulations Toxicity was measured with the modified 48-h acute mysid test. Addition of brine had no effect on the outcome of TIE manipulations. We have concluded that it is operationally easier to add brine as soon as possible after sampling and that effluent tests should be conducted as soon as practical
Impact of sediment partitioning methods on environmental safety assessment of surfactants
Authors: Orth Robert G. , Powell Rebecca L. , Kutey Greg , Kimerle Richard A.
Published: March 2010

Selection of laboratory methods for partitioning and toxicity tests of sediments has a significant impact on interpretation of aquatic safety of surfactants. This is the case for the assessment of the sediment toxicity of C12 linear alkylbenzene sulfonates, LAS. In this study, the batch-equilibrium partition coefficient (Kd) was measured as a function of organic carbon, cation exchange capacity, and quantity of sediments. The quantity of sediment was varied from a low of 5 g per 1,000 ml of water to a level of 500 g to 500 ml of water. The measured Kd decreased by an order of magnitude when the ratio of water to sediments increased to 1:1, and as a consequence of this observation, LAS on suspended solids was included in the quantitaton of LAS in the water phase. When measured Kd values were then used to predict the toxicity (based on known aquatic toxicity concentrations of LAS using Ceriodaphnia dubia), LAS was calculated to be an order of magnitude less toxic by the low-solids test compared to the high-solids test system. This work reaffirms that selection of a laboratory test to assess environmental safety must be made on the basis of its correlation to the real-world behavior of the surfactant.
Computer-Automated predictions of aerobic biodegradation of chemicals
Authors: Klopman Gilles , Zhang Zhutian , Balthasar Donald M. , Rosenkranz Herbert S.
Published: March 2010

A computer program has been developed that can predict the most probable metabolites formed from aerobic biodegradation of chemicals. Predictions are based on an expert evaluation of the parent chemical's molecular structure. The program was designed to recognize molecular fragments within complete chemical structures that are sites of microbial attack. The system is based on a dictionary of transformation rules, consisting of a compilation of molecular transformation operators relevant to microbial attack. The user inputs chemical structures, and the output is a visual or printed display of the potential metabolites resulting from the appropriate metabolic pathways. New chemicals can be evaluated, since the program recognizes structural fragments rather than complete molecular structures.
Use of a freshwater sediment quality database in an evaluation of sediment quality criteria based on equilibrium partitioning and screening-level concentrations
Authors: Hoke Robert A. , Ankley Gerald T. , Peters John F.
Published: March 2010

A sediment quality database was developed for sediments from the Great Lakes and surrounding watersheds. Database file structure was based on commercially available database-management software and is relational in nature Database inputs include sample identification information, whole-sediment and pore-water chemical data, benthic macroinvertebrate species abundances, toxicity test results, and, when available, organism-specific chemical residue data. The database functions as both a laboratory data archival system and as a source of information on the fate and effects of contaminants in freshwater sediments. Database information was used to evaluate two alternative methods for developing sediment quality criteria for dieldrin, endrin, acenaphthene, fluoranthene, and phenanthrene. Sediment quality criteria developed by the U. S. Environmental Protection Agency based on equilibrium partitioning theory were compared to sediment quality criteria or guidelines based on screening-level concentrations calculated by the Ontario Ministry of the Environment and from the database developed in this study. Data from the sediment quality database were also used to determine the frequency with which sediment quality criteria were exceeded in recently (<20 years) collected sediment samples. Excesses beyond the proposed equilibrium partitioning-derived sediment quality criteria were observed in less than 10% of the samples in the database for which chemical concentrations of dieldrin, endrin, acenaphthene, fluoranthene, and phenanthrene were available. Based on the results of this study, sediment quality criteria based on equilibrium partitioning theory and final chronic water-quality criteria are consistent with sediment quality criteria based on screening-level concentrations determined from field samples.
Chlorinated hydrocarbons and mercury in sediments, red-winged blackbirds (Agelaius phoeniceus) and tree swallows (Tachycineta bicolor) from wetlands in the Great Lakes–St. Lawrence River Basin
Authors: Bishop Christine A. , Koster Margie D. , Chek Andrew A. , Hussell David J. T. , Jock Ken
Published: March 2010

In 1991, we collected red-winged blackbird (Agelaius phoeniceus) eggs and tree swallow (Tachycineta bicolor) eggs and nestlings, and sediment samples from 12 wetland sites in the Great Lakes and St. Lawrence River basin. We analyzed for chlorinated hydrocarbons and total mercury and found that biota contained contaminant concentrations which were one to two orders of magnitude above those in sediments. Maximum concentrations (wet weight) of contaminants were found in Akwesasne, St. Lawrence River (PCBs = 18,558.8 ng/g in red-winged blackbird eggs, oxychlordane = 58.8 ng/g and mirex = 40.1 ng/g in tree swallow eggs); Mud Creek, Lake Erie (total mercury = 0.079 μg/g; p,p′-DDE = 4,376.2 ng/g in tree swallow eggs); and Cootes Paradise (211.4 ng/g dieldrin and 115.6 ng/g heptachlor epoxide in tree swallow nestlings). Despite the migratory habits of red-winged blackbirds and tree swallows, agreement among biota and sediment in geographic variation of contaminant concentrations supports the use of these animals as biomonitors of persistent chemicals. Although chlorinated hydrocarbon concentrations in red-winged blackbird eggs were significantly correlated with sediment contamination, the local nature of the tree swallow chick diet suggests that nestlings would be the best indicator of local contaminant trends.
Biological and chemical degradation of ionic ethyllead compounds in soil
Authors: Ou L.-T. , Jing W. , Thomas J. E.
Published: March 2010

Degradation rates and formation of organolead metabolites of ionic triethyllead (TREL) and diethyllead (DEL) in nonsterile and autoclaved surface and subsurface soil samples of Arredondo fine sand were determined using 14C-labeled chemicals. Both [14C]TREL and [14C]DEL in nonsterile and autoclaved soils initially declined rapidly, and both chemicals initially disappeared more rapidly from the surface samples (0 to 15 cm depth) than from the subsurface samples (30 to 45 cm depth), with the exception of the surface sample treated with [14C]DEL. In this soil, [14C]DEL in the autoclaved sample disappeared more rapidly than that in the nonsterile sample. The [14C]DEL was briefly detected in [14C]TREL-treated soil samples, and [14C]DEL remained in the autoclaved samples longer than in the nonsterile samples. Both [14C]TREL and [14C]DEL in nonsterile surface and subsurface samples were initially mineralized rapidly, and at the end of 31 and 28 d of incubation, 15 to 16% and 18 to 19% of the applied 14C was mineralized, respectively. Mineralization was not observed in autoclaved soil samples. It was concluded that both biological and chemical degradation of TREL and DEL in soil occurred, and chemical degradation was probably the major factor contributing to the disappearance of TREL and DEL in soil. The exact extent of chemical degradation is not known. Chemical and physical properties of soil could be altered significantly by autoclaving, and may account for the increase in chemical degradation rates.
Nondegraded metabolites arising from the biodegradation of commercial linear alkylbenzenesulfonate (LAS) surfactants in a laboratory trickling filter
Authors: Kölbener Pius , Baumann Urs , Leisinger Thomas , Cook Alasdair M.
Published: March 2010

The degradation of a commercial linear alkylbenzenesulfonate (LAS) surfactant was examined kinetically in a trickling filter, which allowed simultaneous chemical determinations in the aqueous phase (e.g., DOC) and in the gas phase (CO2). About 60% of the carbon applied as LAS was released as CO2, whereas 15% remained as DOC in the eluate of acclimated trickling filters. The biomass was analysed after the experiment, and it was found to have sorbed about 23 mg LAS/g of dry biomass; this represented about 3% of the LAS applied to the filter. The LAS and the eluates from the trickling filter were further analysed by HPLC and UV and IR spectrometry. The residual carbon from acclimated filters contained no LAS-like material (HPLC), which was obviously subject to quantitative biotransformation. The residual material comprised >50 polar metabolites, some of whose UV spectra differed from that of LAS, and most or all of which were sulfonated. These nondegraded metabolites included carboxylated dialkyltetralinesulfonates and sulfophenylcarboxylates. These residual materials showed no detectable toxicity to algae or Daphnia, and did not significantly lower the surface tension of water.
Biomagnification of organochlorines in lake erie white bass
Authors: Russell Ronald W. , Lazar Rodica , Haffner G. Douglas
Published: March 2010

Biomagnification of HCB and PCBs was measured in a natural fish population of white bass (Morone chrysops) and their prey, emerald shiner (Notropis atherinoides). It was observed that biomagnification occurred only for chemicals with an octanol/water partition coefficient (log Kow) greater than 6.1. Hexachlorobenzene and PCB 52 did not biomagnify while PCBs 87, 138, and 180 showed significant biomagnification in Lake Erie white bass. Biomagnification factors increased proportionately with Kow, and it was concluded that high Kow chemicals were more important in the biomagnification process. Lipid proportions and chemical concentrations in prey fish (emerald shiner) and white bass intestinal contents were consistent with a fugacity model of chemical assimilation from food.
Distribution and biomagnification of selenium in a restored upland grassland contaminated by selenium from agricultural drain water
Authors: Wu Lin , Chen Jianguo , Tanji Kenneth K. , Banuelos Gary S.
Published: March 2010

Kesterson Reservoir was a wetland contaminated with selenium (Se)-enriched agricultural drainage water. As part of the remediation of the selenium contamination, evaporation ponds at Kesterson were dried out and the selenium-contaminated wetlands were transformed into an upland grassland. The distribution of Se in both the soil and vegetation was monitored in these upland grasslands for 5 years. From May 1989 to September 1993 the distribution of soil Se in the sediment did not change significantly, and the soil Se inventory was not remobilized. Biomagnification of selenium in seven sites representing a gradient of soil Se concentrations was examined for three food-chain trophic levels. The pattern of Se bioaccumulation shows that there was a considerable increase from the water-extractable soil Se concentration (source) to the plant (producer) tissue Se concentration and from the grasshopper (primary consumer) tissue Se concentration to praying mantis (secondary consumer) tissue Se concentration. No consistent pattern of increase in Se concentration from the plant to the grasshopper level was apparent. The absolute values of Se bioaccumulation in the insects reflect the available Se concentrations in the soil of the habitat. This relationship indicates that the insects were not actively moving from their local habitat. This discovery suggests that, indeed, a Se biomagnification process did occur in this upland grassland ecosystem. In comparison with the previous state of Kesterson wetland, the upland grassland had Se bioaccumulations less than 10% of those found in the wetland. The upland grassland appears to provide a safer habitat than the wetland with respect to the elevated soil Se concentrations. However, some existing high soil Se concentration sites in the grassland may produce toxic levels of Se in the food chain. Additional research is needed to restore this deteriorated habitat and ensure the safety of wildlife and humans.
Acute effects of chlorinated resin acid exposure on juvenile rainbow trout, Oncorhynchus mykiss
Authors: Kennedy Christopher J. , Sweeting Ruston M. , Farrell Anthony P. , McKeown Brian A. , Johansen Jeffrey A.
Published: March 2010

The effects of an acute exposure to either 14–monochlorodehydroabietic acid (MCDHAA) or 12,14–dichlorodehydro-abietic acid (DCDHAA) were examined in juvenile rainbow trout, Oncorhynchus mykiss. The experimentally determined 96–h LC50 values (and their 95% confidence limits) were 1.03 (0.72, 1.48) and 0.91 (0.70, 1.21) mg/L, for MCDHAA and DCDHAA, respectively. To measure effects on several biochemical parameters, swimming performance, and disease resistance, juvenile trout were exposed for 24 h to sublethal concentrations of one or the other resin acid in an intermittent-flow respirometer. Hematocrit, plasma lactate, and liver protein were significantly affected by exposure to the highest dose (80% of the 96-h LC50 value) of either of the resin acids. Plasma cortisol levels were 14-and 3-fold higher than were controls. Resistance to infection by Aeromonas salmonicida was significantly reduced; the cumulative percent mortalities due to furunculosis in fish exposed to MCDHAA or DCDHAA reached 20 and 26%, respectively. Swimming performance, measured as critical swimming speed (mean values 6.32 ± 0.20 and 5.93 ± 0.15 body lengths per second for MCDHAA and DCDHAA, respectively), was not significantly affected by resin acid exposure.
Action of tributyltin on enzymes of four bacteria
Authors: Tseng Ruey-Kuang , Cooney Joseph J.
Published: March 2010

The effect of tributyltin (TBT) was examined on six enzymes in intact cells and in cytosol and wall/membrane fractions of four bacteria. The organisms′ TBT resistance varied over 2,400-fold: Pseudomonas putida TBT-6 > Pseudomonas sp. BP-4 > Bacillus sp. Me-I > Bacillus sp. MC-24S. TBT is not a general toxicant for enzymes since β-galactosidase, glucose dehydrogenase, and alkaline phosphatase were not affected by it. ATPase was detected in cells of all four organisms but not in their cell fractions; it was inhibited by TBT in cells of Bacillus sp. MC-24S. In intact cells and the membrane fraction, TBT stimulated NADH oxidase at low levels and inhibited it at higher levels, and the more resistant organisms had a higher threshold concentration. In Pseudomonas sp. BP-4, TBT had no effect on glucose-6-phosphate dehydrogenase in cells, but inhibited it in the cytosol fraction. TBT did not affect the periplasmic alkaline phosphatase, which was present in the two Pseudomonas spp. The results support the conclusion that the cell membrane is a site of action of TBT, but that it can also act in the cytoplasm, for the cytosolic enzyme glucose-6-phosphate dehydrogenase was stimulated in cells of Bacillus sp. MC-24S. Enzymes requiring free sulfhydryl groups were inhibited. The patterns of enzyme sensitivity to TBT suggest there may be two resistance mechanisms among these four organisms.
Accumulation and loss of arsenic and boron, alone and in combination, in mallard ducks
Authors: Pendleton Grey W. , Whitworth Molly R. , Olsen Glenn H.
Published: March 2010

Arsenic and boron are common in the environment, and wildlife can be exposed to toxic concentrations through both natural and human-influenced processes. We exposed adult male mallard ducks to dietary concentrations of 300 ppm arsenic as sodium arsenate, 1,600 ppm boron as boric acid, or both and estimated the tissue accumulation and loss rates when the ducks were returned to uncontaminated food. Both elements were accumulated rapidly; equilibrium levels were reached for arsenic in 10 to 30 d and for boron in 2 to 15 d. Accumulation of each element was slowed by the presence of the other in the diet. Boron was eliminated by mallards very rapidly, with few detectable residues ≥ 1 d after removal of boron from the diet; arsenic was also rapidly lost with half-lives of 1 to 3 d (half-lives were not constant throughout the loss period). Arsenic loss rate was not affected by the presence of boron. Arsenic accumulated to the highest level in liver tissue, with blood and brain levels lower; concentrations in the liver and blood were proportional but affected by the presence of boron. Boron concentrations were highest in the blood, followed by the brain and liver; concentrations in the blood and liver were proportional.
Sediment sorption coefficient measurements for four phthalate esters: Experimental results and model theory
Authors: Williams Mark D. , Adams William J. , Parkerton Thomas F. , Biddinger Gregory R. , Robillard Kenneth A.
Published: March 2010

Sediment partition coefficients were measured for four commercial phthalate esters: dihexyl phthalate (DHP), di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and ditridecyl phthalate (DTDP). The experimental procedure was based on the U.S. Environmental Protection Agency (EPA) Test Guideline 796.2750, “Sediment and Soil Adsorption Isotherm.” Three sediments were used: EPA 8 (0.15% organic carbon), EPA 18 (0.66% organic carbon), and EPA 21 (1.88% organic carbon). The Freundlich equation was used to calculate organic carbon-normalized sediment/water partition coefficients (Koc), which averaged 5.26 × 104 ± 4.54 × 103; 4.82 × 105 ± 3.52 × 105; 2.86 × 105 ± 2.74 × 105; and 1.82 × 106 ± 1.05 × 106 for DHP, DEHP, DIDP, and DTDP, respectively. In general, these Koc values did not correlate well to either sediment or chemical properties. This lack of correlation suggested that the measured Koc values are suppressed, potentially as a function of experimental conditions. On the basis of these data, it was decided to investigate the dependence of Koc on sediment solids concentration and dissolved organic carbon. Analysis of these and earlier reported partition coefficient data indicated that measured Koc values for phthalate esters obtained in shake-flask experiments exhibited an inverse dependence on solids concentration. These results were consistent with partitioning models that are discussed. Depending on compound hydrophobicity, the particle-corrected Koc values were from one to three orders of magnitude higher than the measured Koc values. Therefore, if partition coefficient values obtained by using Test Guideline 796.2750 or similar shake-flask procedures are not corrected for solids effect, the estimates of the sediment pore-water concentration of the chemical is likely to be overestimated.
Stimulation of increased short-term growth and development of mayflies by pulp mill effluent
Authors: Lowell Richard B. , Culp Joseph M. , Wrona Frederick J.
Published: March 2010

To determine the food-dependent effects of biologically treated, bleached-kraft pulp mill effluent on mayfly (Baetis tricaudatus Dodds) growth and development, mayflies were exposed to effluent for 2 weeks within artificial streams arranged in a 2 × 3 factorial design (two periphyton food levels - low, high; three concentrations - control river water, 1% effluent, 10% effluent). Although survival was not affected, the effluent had a significant stimulatory effect on growth (resulting in 20 to 50% greater body weights) and development of the wing pads. Furthermore, the initial growth and development trajectories suggest that effluent-exposed mayflies may emerge sooner and at a larger size than nonexposed individuals. A key result was that the stimulatory effects occurred within both the low- and high-food treatments. Thus, the effluent-exposed mayflies grew-faster than even the high-food control animals, which already had access to more food than they could eat throughout the experiment. This shows that the stimulatory effect of the effluent on the mayflies involved more than just an increase in food-availability due to enhanced algal growth in response to nutrients in the effluent. Three possible mechanisms for this growth-enhancement effect are that the effluent (a) increased the nutritive value of the food, (b) enhanced the palatability of the periphyton, inducing increased mayfly feeding, and/or (c) directly stimulated increased mayfly growth via hormonal or other growth-stimulation effects. Further work is required to determine whether the growth stimulation occurred at the expense of future reproductive output.
Avian consumption of blank pesticide granules applied at planting to Iowa cornfields
Authors: Fischer David L. , Best Louis B.
Published: March 2010

Consumption of pesticide granules by free-ranging birds was quantified by applying blank (untreated silica granules to Iowa cornfields at rates varying from 3.9 to 17.3 kg/ha and examining the gizzards of birds collected from these fields for the presence of granules. One or more granules were found in the gizzards of 39% of 256 birds collected. Counts of gizzard granules averaged 0.6 to 0.9 for the three avian groups collected (horned larks, blackbirds, and sparrows). More than 95% of the specimens contained ≤3 granules; the maximum count was 6. On the basis of granule voiding experiments, we estimate that gizzard examinations detected 24% of the granules consumed per day. Median daily consumption for birds in general was estimated to be 2.4 granules, with 95% of individuals estimated to consume ≤18 granules. For the species with the highest consumption rate, the savannah sparrow (Passerculus sandwichensis), median consumption was 11 granules per day, with 95% of individuals estimated to consume ≤23 granules per day. Granule availability on the soil surface was highly correlated with the application rate. Counts within the application band immediately after application averaged 15 granules/ft2 for every 1 kg/ha applied, or about 6% of the granules applied. Our results suggest that when granular pesticides are applied to cropland, many birds may ingest granules, but the numbers ingested will generally be low.
A method for partitioning cadmium bioaccumulated in small aquatic organisms
Authors: Siriwardena P.P.G. Sunil N. , Rana Krishen J. , Baird Donald J.
Published: March 2010

A series of laboratory experiments was conducted to evaluate bioaccumulation and surface adsorption of aqueous cadmium (Cd) by sac-fry of the African tilapia Oreochromis niloticus. In the first experiment, the design consisted of two cadmium treatments: 15 μg Cd · L−1 in dilution water and a Cd-ethylenediaminetetraacetic acid (Cd-EDTA) complex at 15 μg · L−1, and a water-only control. There were five replicates per treatment and 40 fish per replicate. It was found that EDTA significantly reduced the bioaccumulation of cadmium by tilapia sac-fry by 34%. Based on these results, a second experiment was conducted to evaluate four procedures: a no-rinse control; rinsing in EDTA; rinsing in distilled water; and rinsing in 5% nitric acid, for removing surface-bound Cd from exposed sac-fry. In this experiment, 30 fish in each of five replicates were exposed to 15 μg Cd · L−1 for 72 h, processed through the rinse procedures, and analysed for total Cd. The EDTA rinse treatment significantly reduced (p < 0.05) Cd concentrations of the exposed fish relative to those receiving no rinse. It was concluded that the EDTA rinse technique may be useful in studies evaluating the partitioning of surface-bound and accumulated cadmium in small aquatic organisms.
The effects of sublethal dimethoate exposure on the locomotor behavior of the collembolan Folsomia candida (Isotomidae)
Authors: Sørensen Freddy Fisker , Bayley Mark , Baatrup Erik
Published: March 2010

The locomotor behavior of the collembolan Folsomia candida Willem 1902 (Isotomidae) was automatically quantified during exposure to soil treated with sublethal concentrations of dimethoate. During the 36 h of measurement, significant changes were seen in walked distance, mean velocity, and turning rate. It is concluded that these end points provide a sensitive measure of toxic stress.
A mechanistic model of contaminant-induced feeding inhibition in Daphnia magna
Authors: Allen Yvonne , Calow Peter , Baird Donald J.
Published: March 2010

Particles in water ubiquitously carry a net negative charge. It was hypothesised that the interaction between suspended particles and pollutants in water results in a process of adsorption that can be related to the charge of the pollutant concerned, and that this is a potential route of pollutant uptake by aquatic animals such as particle-grazing zooplankton. Experiments with the alga Chlorella vulgaris were conducted to test the hypothesis that pollutant-induced feeding inhibition in the cladoceran Daphnia magna was dependent on this mechanism. Using compounds differing in charge, results supported the hypothesis that, while all compounds were capable of causing feeding inhibition, electropositive species such as cadmium induced effects close to the chronic no-effect concentration, whereas electronegative species such as vanadium induced effects only at or close to lethal levels. It was suggested that for those compounds capable of causing feeding inhibition at sublethal concentrations, this inhibition would be a key mechanism impairing reproduction and growth, with potential consequences for grazing animals at population and community levels in natural ecosystems.
Predicting chronic lethality of chemicals to fishes from acute toxicity test data: Theory of accelerated life testing
Authors: Sun Kai , Krause Gary F. , Mayer Foster L. , Ellersieck Mark R. , Basu Asit P.
Published: March 2010

A method for modeling aquatic toxicity data based on the theory of accelerated life testing is presented, and a procedure for maximum likelihood fitting the proposed model is developed. The procedure is computerized as software, which can predict chronic lethality of chemicals using data from acute toxicity tests. A database of various chemicals and fish species was analyzed. When the calculated values of prediction were compared to the maximum acceptable toxicant concentrations obtained from actual chronic toxicity experiments, the new technique provided accurate predictions. Problems in using the “maximum acceptable toxicant concentration” and applications of the proposed method are discussed.
Fitness trade-offs of Selenastrum capricornutum strains selected for rapid growth on copper-spiked solidified nutrient medium
Authors: Benjamin Richard B. , Klaine Stephen J.
Published: March 2010

Stock (ancestral) cultures of Selenastrum capricornutum grew optimally in low Cu liquid nutrient medium (LNM) containing 0.004 μg L−1 Cu2+. Growth of stock cultures was optimized on low Cu solidified nutrient medium (SNM) containing 20 μg L−1 Cu2+. Cell strains (clones) were isolated from unusually large colonies on high Cu SNM (1,000 μg L−1 Cu2+). Most isolated strains performed the same as ancestral populations in high Cu LNM (50 μg L−1 Cu2+), but three strains grew more slowly. These “variant strains” were Cu tolerant on SNM (equal growth with low and high Cu) and produced larger colonies than did the ancestral population on both low and high Cu SNM. In contrast, colonies from ancestral cell samples grew more slowly in high versus low Cu SNM. No significant growth differences were observed between ancestral populations and variant strains in low Cu LNM, suggesting low fixed costs of adaptation to SNM. However, slower growth of variant strains in high Cu LNM constituted a fitness trade-off associated with adaptation. Rapid adaptation to pollution may often result in important biological trade-offs even when costs of adaptive mechanisms are low.