bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of System Design and Reproducibility to Estimate Bioconcentration of Di-n-hexylphthalate by Daphnia magna
Authors: Gloss SP , Biddinger GR 
Published: December 2008

Duplicated flow-through exposure systems consisting of two diluters, operated simultaneously, were used to compare the bioconcentration of 14C-di-n-hexylphthalate (14C-DHP) by Daphnia magna under single-species (modular) or multispecies (mixed) model formats proposed for use as microcosms to estimate bioconcentration.
Triplicate exposures of Daphnia in each diluter system were made under conditions which provided the following possible sources of DHP: (1) water only fed (Daphnia in mixed model fed unlabeled algae), (2) water only unfed, (3) water plus food (labeled algae), and (4) food only.
Water levels of 14C-DHP were maintained at approximately 0.22 μg/L. Algae (Selenastrum capricornutum), previously exposed in water with 0.08 µg/L 14C-DHP and used to feed Daphnia, contained approximately 0.11 µg 14C-DHP/g. Results at 24 h showed significantly (P &lt; 0.05) higher accumulation of 14C-DHP in Daphnia exposed to the combination of contaminated food and water than any other treatment. Accumulation from exposures only to food was not different from controls. No differences were detected between the same treatments in the duplicate exposure systems. Coefficients of variation within a treatment combining replicates from both diluters (n ≥ 4) averaged 18% and ranged from 8 to 32%.
Exposures to 14C-DHP in water only (Daphnia fed) were conducted in a mixed model system wherein Daphnia were subjected to controlled predation by bluegill sunfish (Lepomis macrochirus). Results from the mixed model systems suggested that steady-state accumulation took longer than seven days to achieve. The measured bioconcentration factor (BCF) of 3250 for 14C-DHP in D. magna was similar to values reported for other phthalate esters in microcrustaceans.
Measured BCFs for the water only (48 h), food plus water (48 h), and the mixed model system (14 days) were 1066, 1486, and 3254, respectively. Calculated BCFs, using a first-order steady-state equilibrium model were 998, 1414, and 4655, respectively, for the same three treatments. All BCFs reported are for total 14C activity on a wet-weight basis.
Sediment Microbial Activity Tests for the Detection of Toxicant Impacts
Authors: Burton GA , Lanza GR 
Published: December 2008

Sediments are a major factor influencing the fate and concentration of some toxicants. The use of sediment microbial activity in water quality assessment could enhance our ability to understand the impact of many toxicants. Sediments from six diverse lake sites were spiked with arsenic species, and effects on microbial activity were assessed with a test battery measuring dehydrogenase (TTC), acridine orange direct counts (AODC), formazan crystal production (INT), phosphatase, proteolysis, total direct counts (DC), direct viable counts (DVC), and total plate counts (TPC). Individual tests were modified for use in sediments. Oxygen, sediment age and volume, incubation time, diluent type, nutrient amendment, and agitation were studied as major variables.
Phosphatase and TTC activity were higher in microaerobic sediment microcosms. DVC accurately detected microbial activity in water but not in sediments. INT assays revealed that sediments contain higher percentages of dormant bacteria than overlying waters. Arsenic generally failed to suppress enzyme activity in nutrient-stimulated sediments. TTC, phosphatase, and INT activity showed variable responses to arsenic additions, depending on test conditions. Proteolysis was suppressed by arsenite under aerobic conditions after one month. Sediment bacterial isolates were not sensitive to arsenate, but they were very susceptible to arsenite. Important test modifications enabling accurate assessment with these assays include both sediment and nutrient concentrations, diluent type, and incubation condition.
The activity test sequence described here demonstrates the diversity of microbial community response to model toxicants. The use of several microbial activity tests best defines the degree of stimulation or inhibition in sediment toxicology. The diverse and complex nature of typical sediments requires careful pretesting before accurate activity assays can be run.
Using the Natural Detoxification Capacities of Marine Organisms to Assess Assimilative Capacity
Authors: Brown DA , Bay SM , Gossett RW 
Published: December 2008

A test for determining the toxicity of contaminants in the environment is described, with a proposal that this test can be used to determine assimilative capacity for some contaminants. This test is based upon the observation that organisms have a measurable capacity to internally detoxify, and thereby safely assimilate, metal and organic contaminants. Toxic effects of contaminants appear to coincide with saturation of in vivo detoxification systems with metal or organic contaminants and appearance of these contaminants at intracellular sites of toxic action. A simple gel chromatography procedure has been devised to determine the intracellular partitioning of contaminants between an enzyme-containing (ENZ) pool which is a site of toxic action for both metals and organic compounds, a metallothionein-containing (MT) pool which is a site of detoxification for metals, and a glutathione-containing (GSH) pool which is a site of detoxification for organic compounds.
Several marine species including sea urchins, scorpion fish, croakers, and Dover sole were sampled from populations living near and away from a major California municipal wastewater outfall, and the partitioning of contaminants between intracellular pools was determined. Cadmium, copper, and zinc appeared to be successfully detoxified by the MT pool in all field-exposed organisms. Laboratory exposures were used to measure cadmium-detoxification capacity in tissues of scorpion fish; the relative sensitivity to cadmium was in the order: kidney &gt; gills &gt; intestine &gt; liver. Oxygenated metabolites appeared to have exceeded the capacity of the GSH pool in field-exposed croakers and Dover sole, with fatty livers and fin erosion, respectively.
Therefore, at present levels of contamination of southern California coastal waters, the detoxification (assimilative) capacity of some marine organisms for certain trace metals does not appear to have been exceeded, whereas that for organic contaminants has.
Sediments and their associated microorganisms were also suggested to have a measurable capacity to detoxify contaminants by binding them so that they are not bioavailable or by degrading them to nontoxic forms.
Aquatic Safety Assessment of Chemicals Sorbed to Sediments
Authors: Adams WJ , Kimerle RA , Mosher RG 
Published: December 2008

Chemical safety is assessed by the relationship of toxic effects to exposure concentrations, that is, by defining the margin of safety. To date, however, these principles have been applied only to organisms in the water column of aquatic ecosystems. A deficiency exists in our ability to understand the aquatic hazard of chemicals that are sorbed to sediment.
Studies to define the key route of exposure (interstitial water, water column water, sediment or food) were conducted with Kepone and the midge, Chironomus tentans, in partial life cycle static and flow-through tests. The endpoints measured were survival, growth, and bioaccumulation. Seven separate 14-day partial life cycle tests were conducted.
The no effect-effect concentrations for midges exposed to Kepone in the water were &gt;5.4 &lt;11.8 ppb. No effects were observed when the midges were fed food containing up to 17 900 ppb Kepone. In the sediment exposure studies, the no-effect concentrations varied from 3000 to 36 000 ppb depending upon the organic carbon content of the sediment. In all the sediment exposure studies, water column concentrations were below the water exposure chronic effect levels (11.8 ppb), and effects were observed only when the sediment interstitial column concentrations exceeded the 11.8 ppb water column exposure chronic effect level. Measured bioaccumulation factors for each study showed little variability when the midge tissue concentrations were divided by the sediment interstitial water concentrations. Calculations of the bioaccumulation factors based on water column concentrations or sediment concentrations were highly variable.
It can be concluded from our studies with Kepone and C. tentans that the key route of exposure is from the interstitial water and/or the water at the sediment/water interface. Toxic effects can be expected to occur in benthic invertebrates only if the chemical concentration is high enough in the sediments such that the equilibrium interstitial water concentration reached by desorption is equal to or higher than the concentration demonstrated to cause an effect in a water exposure test. Interpretation of aquatic hazard and calculation of safety factors for nonionic organic chemicals sorbed to sediments should be based on the concentration of the chemical in the sediment interstitial water, which is a function of the chemical's sediment partition coefficient (Kp), concentration of chemical on the sediment, and the organic carbon content of the sediment.
Piezocone Penetration Testing in Soft Cohesive Soils
Authors: Tumay MT , Acar YB 
Published: December 2008

The difficulty in obtaining samples for laboratory testing in very soft cohesive marine deposits necessitates the use of in-situ testing methods. Piezocone penetrometers that measure the tip resistance qc, sleeve friction fs, and the generated pore pressure u, are one of the most repeatible and reliable in-situ testing methods.
This study presents the experience obtained by the authors in analysis and evaluation of the soil characteristics with the use of piezocone penetrometers. Emphasis is given to the analysis of the penetration pore pressures.
Apart from the information obtained from the penetration pressures, their dissipation when the penetration is stopped gives valuable information on the time-deformation characteristics of the deposit. Upon the conclusions of theoretical and experimental studies, a practical method for determining in-situ coefficient of consolidation values is presented. While it is observed that the values obtained from penetration pore-pressure dissipations are generally greater than oedometer values, the present state of the art indicates that they better represent the in-situ behavior.
The Phenomenon of Sample Tube Plugging
Authors: Holt JR , Ims BW 
Published: December 2008

In order to overcome the limited recovered lengths and sample disturbance associated with driven sampling, long stroke hydraulic push or piston samplers have been developed for offshore operations in recent years. Use of such samplers, however, does not always result in recovered sample lengths consistent with the distance pushed. A detailed review of sample recovery for several offshore investigations has shown this phenomenon to be common to all soil types.
It is demonstrated that the recovered sample lengths can be predicted to a high degree of accuracy by comparing the friction resistance developed on the inside of the tubes with the soil bearing capacity as determined from cone penetrometer tests.
Implications of the findings are discussed with particular reference to sample disturbance.
Liquefaction Potential of Sediment in the Northern Bering Sea
Authors: Winters WJ 
Published: December 2008

The liquefaction potential of sediment in Norton Sound and the northern Bering Sea was evaluated by estimating the liquefaction susceptibility of the material from in-situ and laboratory tests in terms of earthquake and wave loads required to liquefy the material, and then comparing estimated behavior with anticipated loadings caused by frequent storm waves in the relatively shallow water depths and infrequent earthquakes.
In-situ cone penetration tests (CPT) were performed at 13 stations. After the CPT data were transformed into equivalent standard penetration test (SPT) blow counts, analyses were performed that determined earthquake accelerations and sustained relative storm wave heights that would cause liquefaction.
Vibratory core samples, up to 6 m long, were obtained in silty sand grading to sandy silt near many of the CPT locations. Results of cyclic triaxial tests performed on those samples were used to calculate earthquake accelerations and sustained storm wave heights that would liquefy the sediment.
Liquefaction susceptibility estimates from laboratory tests typically were lower than those from in-situ tests; nevertheless, both approaches yielded the same conclusions for regional assessment of liquefaction potential. Wave and earthquake loadings are not strong enough to cause significant amounts of liquefaction in most areas.
A Laboratory Extraction Method to Simulate Codisposal of Solid Wastes in Municipal Waste Landfills
Authors: Francis CW , Maskarinec MP , Goyert JC 
Published: December 2008

The objective of this research was to develop a laboratory extraction method for solid wastes that simulates concentrations of inorganic and organic constituents in leachates resulting from codisposal with municipal wastes in landfills. A scientific rationale and a data base are presented supporting the use of such an extraction method to characterize the potential hazards of leachates from a solid waste codisposed with municipal waste in a landfill containing about a 95:5 ratio of municipal and industrial waste, respectively. Two field lysimeters, each containing approximately 1.5 Mg of assorted municipal wastes, were used to generate a municipal waste leachate (MWL) that in turn was used to leach four industrial wastes under anoxic simulated codisposal conditions.
Leachates from the four industrial wastes were monitored for concentrations of inorganic and organic constituents over 79 days at a liquid/solid ratio of MWL and industrial waste of approximately 20:1, similar to the liquid/solid ratio currently being used in the extraction procedure to determine toxicity under the Resource Conservation and Recovery Act. Air-tight Tedlar® bags were used to collect leachate to avoid loss of volatile organic compounds and to maintain an anoxic environment. Data from the field lysimeter test facility were used to identify concentrations of “target” constituents (those constituents in the leachates of the industrial wastes that were observed at concentrations statistically higher than those observed in the control leachates). This data base was used as a model to evaluate several laboratory extraction methods that might be used to simulate the target concentrations.
Evaluation of Chemical and Biological Methods for the Identification of Mutagenic and Cytotoxic Hazardous Waste Samples
Authors: Andon B , Jackson M , Houk V , Claxton L 
Published: December 2008

To assist in the development of methods for identifying potentially hazardous wastes, we have conducted studies on the extraction of toxicants from several solid waste samples. The extracts were tested for toxicity by the Chinese hamster ovary (CHO) cytotoxicity test and for mutagenic potential in the Salmonella histidine reversion assay. A new technique was also employed that measured the mutagenicity of neat waste samples by coupling thin layer chromatography (TLC) with the Salmonella histidine reversion assay.
The wastes selected for study were coke plant waste, herbicide manufacturing acetone-water effluent, and oil refining waste. Three extraction solvents—ethanol, dichloromethane (DCM), and dimethylsulfoxide (DMSO)—were chosen based on their solubility and compatibility with bioassay procedures. Each sample was divided into three parts and extracted with each of the three solvents separately.
All extracts were tested in the Salmonella assay at five dose levels with five Ames tester strains in the presence and in the absence of an exogenous metabolizing system. The DMSO and DCM extracts were utilized for CHO cytotoxicity evaluations. The three neat waste samples and two extracts were assayed by the Salmonella/TLC technique. In addition to the biological assessments, the gross chemical parameters for each sample were determined.
Results showed that coke plant waste and herbicide manufacturing acetone-water were mutagenic to S. typhimurium with the standard plate test. With the Salmonella/TLC technique, the coke plant waste was mutagenic and oil refining waste was both toxic and mutagenic. Oil refining waste was also toxic to CHO cells. Results of the gross chemistry determinations showed the three samples to have a wide range of solid content, total organic content, and extractables. Evaluation of the chemical extraction methods demonstrated few differences in extraction capabilities with respect to mutagenic activity.
Generalized Behavior of Laterally Loaded Vertical Piles
Authors: Gleser SM 
Published: December 2008

A method previously presented by the author (in ASTM STP 154) is generalized to encompass soils having nonlinear p-y characteristics. This results in a method that can handle, but is not restricted to, pile-soil systems having (1) piles greater than 9 m (30 ft) in length having free, fixed, or partially fixed heads, and any cross-sectional shape and length relationship, for example, constant, tapered, or stepped, and of any materials or combination of materials; (2) soils of any variation with depth, whether homogeneous, stratified, or combinations thereof, and having p-y characteristics of any nature; (3) ability to qualitatively and quantitatively predict behavior and stresses under static, fluctuating, and repetitive lateral loadings, or where larger emergency loads can be interspersed between normal loads. Ways are suggested for dealing with each of these factors. In addition, a method is proposed for obtaining the effective soil constant at a given site for a range of lateral loads, using empirical test data from free-head piles of the same characteristics subjected to lateral loads. The method is validated by use on previously published data of a comprehensive series of tests on free-head piles by Assadeh and Davison (Journal of the Soil Mechanics and Foundation Division, Proceedings of the American Society of Civil Engineers, Vol. 96, No. SM5, Sept. 1970, pp. 1583–1603). Using the soil constants resulted in computed load-deflection curves closely approximating actual data. These constants are used in turn to compute the expected deflections and pile stress of those same piles under fixed-head conditions.
A serendipitous finding of the analysis was that there is a significant shape factor affecting the ability of piles to mobilize soil resistance to lateral loads, for example, under any given lateral load applied to free-head piles having approximately equal moments of inertia, those having circular cross sections were substantially more resistant to lateral movement than square or H-beam cross sections. This in turn significantly altered the effective soil modulus.
To determine the usefulness of the method in economic as well as structural design, an analysis was made of a built-up pile consisting of a 360-mm (14-in.) H-beam cut diagonally along its length and rewelded to form a tapered I beam 500 mm (20 in.) at the butt and 200 mm (8 in.) at the tip, with constant flanges. Although having the same weight as the basic H beam, the tapered pile was computed to have a lateral deflection under a load of 13 000 kg (30 000 lb), which is half of that of the basic beam under free-head conditions and 0.6 of that under fixed-head conditions.
Laterally Loaded Piles and the Pressuremeter: Comparison of Existing Methods
Authors: Briaud J-L , Smith T , Meyer B 
Published: December 2008

The first part of this article deals with the determination of the critical depth Dc, below which the ground surface has little influence on the soil-structure interaction problem, and with the variation of soil resistance within that critical depth. A new approach is proposed to determine Dc using the relative rigidity of the pile with respect to the soil strength as measured by the pressuremeter limit pressure.
The second part of the article summarizes seven pressurementer methods to predict the lateral behavior of piles. Predictions by four of the methods are compared with the results of a full-scale load test. All methods predict the measured behavior with reasonable accuracy suggesting that the pressuremeter provides a sound testing base for the behavior prediction of laterally loaded piles.
Testing and Analysis of Two Offshore Drilled Shafts Subjected to Lateral Loads
Authors: Long JH , Reese LC 
Published: December 2008

A lateral-load test was conducted at an offshore site on two 1.22-m-diameter drilled shafts penetrating through 13.1 m of dense sand overlying clay. The lateral-load test was conducted by pulling the two shafts toward each other under a specified lateral load and then relaxing the load to zero. This procedure was repeated for 40 cycles at each load level. With each load increase the application sequence was repeated to a maximum lateral load of 500 kN. Throughout the test, measurements were made of deflection and slope at the top of the shaft, and measurements of slope along the length of the shaft were obtained using a slope inclinometer.
A computer model was used to predict the behavior of a drilled shaft under the test conditions, and computed results were compared with measured results. At a lateral load of 500 kN, values of deflection were computed to be 20 to 30% less than measured.
Effect of Irradiation Temperature on the Precipitation in Cold-Worked Titanium-Stabilized Type 316 Stainless Steel
Authors: Gilbon D , Le Naour L , Rivera C , Lorant H 
Published: December 2008

In this work, we describe the precipitation behavior of cold-worked titanium-stabilized Type 316 stainless steel irradiated with neutrons in the temperature range of 464 to 596°C. The samples were cut from a Rapsodie fuel pin cladding and were examined by transmission electron microscopy and energy dispersive X-ray micro-analysis.
The microstructure is characterized by the precipitation of G and eta phases in the temperature range of 464 to 521°C, and TiC and Laves phases above 590°C. The results also emphasize the important effect of dose rate on the precipitation, and particularly on the chemical composition of the Laves phases. The most striking feature is the appearance above 546°C of thin platelets whose diffraction characteristics are coherent with the hexagonal Ni3Ti phase. The formation of a high density of these planar may partly explain the low swelling of cold-worked titanium-stabilized Type 316 stainless steel above 540°C.