bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aerobic and anaerobic soil degradation of a hexahalocyclohexane mixture
Authors: Lickly Tim D. , Rhinehart Wayne L. , Murphy Patrick G. , Mendoza Celia G. 
Published: March 2010

Abstract
Soil degradation studies of a mixture of [14C]hexahalocyclohexanes, consisting primarily of α-pentabromochlorocyclohexane (˜55%), α-tetrabromodichlorocyclohexane (˜25%) and α-tribromotrichlorocyclohexane (˜10%), indicated rapid degradation, with half-lives estimated to be approximately 10 d and less than 5 h, respectively, for the aerobic and anaerobic (flooded) degradation when loam and sandy loam soils were amended with approximately 1.5 ppm of the mixture. Greater than 50% of the [14C]hexahalocyclohexane mixture was converted to 14CO2 in 90 d under aerobic soil conditions. Approximately 75% of the [14C]hexahalocyclohexane mixture was converted to volatile compounds within Id under anaerobic soil conditions. The volatile compounds observed under anaerobic conditions did not include 14CO2 or 14CH4.
Movement and persistence of 2,4,5-trichlorophenoxyacetic acid in a forest watershed in the Eastern United States
Authors: Norris Logan A. , Loper B. R. , Montgomery M. L. , Kochenderfer J. N. 
Published: March 2010

Abstract
Approximately 98% of a 22-ha forest watershed in West Virginia was treated with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) at a rate of 2.24 kg/ha. The average herbicide residue in the foliage and tips of four species of vegetation was 151 mg/kg immediately after application, 61 mg/kg after 1 week, and 24, 7.9, 4.6, 0.07 and less than 0.01 mg/kg after 1, 3, 6, 12 and 24 months. Residues in the forest floor decreased from 31 mg/m2 (0.31 kg/ha) immediately after application to 2 mg/m2 after 12 months and 1.6 mg/m2 after 24 months. The concentration in 0 to 15 cm soil decreased by 90% in 1 month and then remained relatively constant. No 2,4,5-T (&lt;0.01 mg/kg) was found deeper than 15 cm after 3 months. Throughfall precipitation transferred 34 mg/m2 to the forest floor, with 80% occurring the first 2 weeks after application, during which time there was 16.9 cm precipitation. About 6 mg/m2 was transferred to the forest floor in freshfall litter. The highest concentration of 2,4,5-T in stream water during application was 0.012 mg/L, and the highest concentration during more than 2 years of measurement was 0.05 mg/L, measured 5 h after beginning application and about 1 h after 0.18 cm precipitation. No 2,4,5-T was found in stream water more than 13 d after application. A total of 8.4 g (0.017% of the amount applied) 2,4,5-T was discharged from the watershed in streamflow. The concentrations of 2,4,5-T in this forest are substantially below those likely to cause any adverse effects in animals.
Interpreting results from biodegradability tests of chemicals in water and soil
Authors: Howard Philip H. , Banerjee Sujit 
Published: March 2010

Abstract
Biodegradability testing is examined and the many factors affecting extrapolation of laboratory biodegradation results to microbial degradation in the environment are discussed. Recent advances in the understanding of the effects of the concentration and nature of various nutrients and organic substrates and modeling the microbial kinetics of degradation are reviewed. The advantages and disadvantages of screening methods and grab sample testing are discussed. The importance of groundwater biodegradation is also examined. Research needs are identified and guidelines are given to select various testing procedures to model diverse environmental situations.
Application of single- and multiphasic michaelis-menten kinetics to predictive modeling for aquatic ecosystems
Authors: Lewis David L. , Holm Harvey W. , Hodson Robert E. 
Published: March 2010

Abstract
The transport, fate and effects of many toxic chemicals in aquatic ecosystems are largely mediated by microbial transformations. In our research, we have assumed that the transformations are a result of enzymatic reactions, and thus follow Michaelis-Menten kinetics. Using diverse field-collected and laboratory microcosm microbiota, we obtained sufficient experimental data to reach some general conclusions concerning the strengths and weaknesses of using Michaelis-Menten kinetics in making environmental predictions. We concluded that this approach is best suited to predicting microbial transformations for pollutant concentrations of approximately 10−7 M or lower. The approach also is applicable to high pollutant concentrations (saturated systems), provided that toxic effects of the pollutant and adaptation are considered. Unfortunately, most experiments have been conducted in the upper 10−7 to 10−4 M pollutant concentration range, which may approach saturation for a portion of enzymatic systems in a mixed population. This range is ideal for analytical purposes, but could be confounded by mixed-order and multiphasic kinetics, toxic effects of the pollutant and adaptation. Adaptation, mass-transport effects, multiphasic kinetics of pollutant uptake and transformation, and suppression of transformation by diauxie, biologically produced inhibitors, and other xenobiotic chemicals are some of the factors that we believe need to be more thoroughly evaluated to improve predictive modeling capabilities.
A rating system for predicting the appearance of temik® aldicarb residues in potable water
Authors: Back Richard C. , Romine R. R. , Hansen James L. 
Published: March 2010

Abstract
The potential for TEMIK®; aldicarb pesticide to appear in potable water is estimated by applying a numerical indexing system. The index recognizes four basic categories of factors that affect the potential of chemical residues to occur in potable water. Values are assigned to the factors based on published data, designed laboratory tests and estimates based on knowledge about the use of the pesticide. An area with a high index number is expected to have a higher potential for aldicarb residue to appear in potable water than an area with a lower number. The index does not give quantitative values for aldicarb residue concentrations but indicates the sensitivity of an area to significant intrusion into water supplies. The system has been calibrated by adjusting scoring to reflect results of on-site monitoring from different climatic and geographical areas. The reliability of the index is believed to be comparable in accuracy to simulation modeling and has the advantage of greater adaptability to a wide variety of areas.
Biological methods for determining toxicity of contaminated freshwater sediments to invertebrates
Authors: Nebeker Alan V. , Cairns Michael A. , Gakstatter Jack H. , Malueg Kenneth W. , Schuytema Gerald S. , Krawczyk Daniel F. 
Published: March 2010

Abstract
Methods are presented for using Daphnia magna, Hyalella azteca, Gammarus lacustris, Chironomus tentans and Hexagenia limbata to screen freshwater sediments for acute and chronic toxicity, bioaccumulation potential and in situ toxicity. The 48-h Daphnia tests are recommended as inexpensive, uncomplicated and sensitive acute methods. Hyalella and Chironomus are the recommended benthic test organisms, as they are easy to rear and test, they remain in intimate contact with the sediment and they exhibit high control survival. Verification studies (published elsewhere) evaluating the recommended methods and organisms are briefly summarized.
A rapid aquatic toxicity assay utilizing labeled thymidine incorporation in sea urchin embryos
Authors: Jackim Eugene , Nacci Diane 
Published: March 2010

Abstract
Aquatic toxicity was evaluated in the sea urchin embryo (Arbacia punctulata) by the inhibition of tritiated thymidine incorporation after a brief exposure to toxic chemicals. In preliminary trials, using eight compounds of varying toxicities, results accurately predicted reduced survival and morphological delay after 48-h exposures (r2 = 0.97). Excellent correlations also exist between these calculated median effective concentrations (EC50 values) and literature-derived acute LC50 values for two other aquatic species. Arbacia is a useful surrogate species for assay: well-studied, easily cultured and fertile virtually year round. The simplicity and speed of this test system lends itself to screening large numbers of compounds, mixtures or water samples.
Aquatic fate of synfuel residuals: Bioaccumulation of aniline and phenol by the freshwater phytoplankter Scenedesmus quadricauda
Authors: Hardy John T. , Dauble Dennis D. , Felice Lawrence J. 
Published: March 2010

Abstract
Coal liquefaction compounds could, through accidental release, enter aquatic environments. Experiments were conducted to determine the kinetics, degree of bioconcentration and stability of two of these compounds at the first level of the aquatic food web. We exposed the freshwater phytoplankter Scenedesmus quadricauda to sublethal concentrations of 14C-labeled phenol and aniline. Both accumulation and elimination occurred within a few hours and followed hyperbolic kinetics. Results indicate that substantial quantities of accumulated compounds remain as the parent compound (22% for phenol and 52% for aniline) for up to 24 h and could be available to animals higher in the food web. Bioconcentration factors [(nm parent compound/cm3 phytoplankton) ÷ (nm parent compound/cm3 water)] were 3.5 for phenol and 91 for aniline.
Fate and biological effects of pentachlorophenol in outdoor ponds
Authors: Crossland N. O. , Wolff C. J. M. 
Published: March 2010

Abstract
Various laboratory methods and mathematical models are being developed to assess the hazards of chemicals to aquatic environments. Although the approach is generally accepted, many of the methods and models have not been validated by comparison with field observations. In this study we compared predictions of the fate and biological effects of a reference compound, pentachlorophenol (PCP), with observations in experimental outdoor ponds. PCP was repeatedly applied to the subsurface water of three ponds with the aim of maintaining an average concentration of 50 to 100 μg/L in the water for a period of 30 d. At this dosage level chronic toxicity to some organisms was expected.
Evaporation, sorption, hydrolysis, biodegradation and indirect phototransformation of PCP were expected to be of minor importance under the environmental conditions encountered in the ponds. The partition coefficient of PCP between water and wet sediment was predicted to be near unity and the dominant loss process to be direct phototransformation. The rate of this process was calculated using the SOLAR mathematical model. Data used for this calculation were the light absorption spectrum of PCP, the quantum yield for the light-activated reaction, depth and light attenuation of pond water, season and latitude. After correcting for cloud cover, the calculated rate constant was 0.23 to 0.46 d−1. In good agreement with the calculations, the observed rate of loss was 0.15 to 0.34 d−1, and there was no evidence of accumulation in sediment.
The results of chronic toxicity tests with various species of fish, two species of snail and the planktonic crustacean Daphnia magna Straus were consistent with field observations. Chronic toxicity to filamentous algae (Chara sp. and Enteromorpha sp.) was observed in the field, and their death and decay were responsible for depression of dissolved oxygen concentrations and fish deaths. Direct effects on filamentous algae and the indirect effects caused by their death and decay could not be predicted in the absence of relevant laboratory data.
Detoxification rates of chlorinated solutions as determined by the half-life of biological activity with Daphnia magna
Authors: Doherty Francis G. 
Published: March 2010

Abstract
Data are presented that discourage the use of total residual chlorine (TRC) and free residual chlorine (FRC) levels in setting water quality criteria for chlorine and chlorinated carrier molecules. Repetitive static acute toxicity tests for aging solutions of chlorinated complexes with Daphnia magna permit generation of biological half-lives for direct comparison with analytically derived concentrations of TRC and FRC. The results indicate a strong similarity in the decline of toxic effects on D. magna and TRC for an aging solution of 1,3-dichloro-5,5-dimethylhydantoin (DCDMH), although no such similarity exists between these two measures for aging solutions of chlorine and trichloro-S-triazinetrione (TCTT). Repetitive toxicity tests with aging DCDMH generated toxic decay curves with coefficients of determination (r2) exceeding 73% while exhibiting a minimum decay rate of -0.10. TRC data for DCDMH exhibited an r2 of 93% and a decay rate of -0.07. The r2 values for the chlorine series ranged from 15 to 60% for the toxic effects decay curve, as compared with 76% for analytically derived data. The TCTT r2 values for these same parameters were 23 to 64 and 84%, respectively. Both chlorine and TCTT presented definable, consistent decreases in TRC levels over the course of the studies, while the observed biological effects oscillated widely from test to test within a series. These results demonstrate that the standard reported parameters of TRC and FRC are inadequate for setting effluent limitations on chlorinated discharges because they are inconsistent in measuring the toxic constituents of these solutions.
Assessment of priority pollutant concentrations in the United States using storet database
Authors: Staples Charles A. , Werner A. Frances , Hoogheem Thomas J. 
Published: March 2010

Abstract
The examination of the 80,000,000 STORET data points for priority pollutant concentrations yielded principles for system usage to determine the individual occurrence of these pollutants in U.S. waterways. A case study on a representative priority pollutant (butyl benzyl phthalate) is presented in detail to highlight the characteristics of the database. The use of data from the 1980s only is recommended, based on the number of data points and the likelihood that better quality assurance practices were employed. Mean values should not be used because aberrant values dominate the additive mean and can exceed statistical probability (p &lt;&lt; 0.01). Since geometric mean calculations are not readily available within the system, the use of median values based on ambient or effluent sampling points and excluding landfill sampling sites is recommended. Careful documentation of nondetectable values is also necessary to reduce errors associated with statistical analysis. Eighty-six of the 110 (78%) organic priority pollutants are not detectable in U.S. waterways. Of the 24 chemicals detected, only 5 exceed an ambient median water concentration of 0.3 μg/L. Ninety-five of the 110 (86%) are not detectable in industrial effluents; the maximum median value of 10 μg/L was reported for four organic priority pollutants. Seventy-nine percent of the organic priority pollutants are not detected in sediments; all but seven medians are less than 15 μ/kg. Eighty-seven percent are not detected in biota; all but three medians are less than 0.25 mg/kg.
Chronic toxicity of di-n-butyl and di-n-octyl phthalate to Daphnia magna and the fathead minnow
Authors: McCarthy J. F. , Whitmore D. K. 
Published: March 2010

Abstract
The toxicities of di-n-butyl phthalate (DBP) and di-n-octyl phthalate (DOP) were assessed by measuring the effect of exposure to these compounds on the fecundity of Daphnia magna and on the hatching and survival of the early life stages of the fathead minnow Pimephales promelas. For D. magna, exposure to 1.8 mg/L DBP or 1.0 mg/L DOP caused a significant reduction in reproduction. Doses of 0.56 mg/L DBP or 0.32 mg/L DOP had no significant effect in decreasing reproduction. Survival of fathead minnow embryos was decreased by exposure to 1.8 mg/L DBP; none of the embryos exposed to this dose hatched successfully. Hatching and larval survival were affected by exposure to 1.0 mg/L DBP, but not to 0.56 mg/L. Exposure to DOP did not affect survival of either early embryos or larvae of the fathead minnow at doses up to 10 mg/L (the highest dose tested). Hatching of the embryos was significantly decreased at 10 mg/L, but not at 3.2 mg/L DOP.
Toxicity of abate® 4E (temephos) in mallard ducklings and the influence of cold
Authors: Fleming W. James , Heinz Gary H. , Franson J. Christian , Rattner Barnett A. 
Published: March 2010

Abstract
Diets mixed to contain 0, 0.1, 1.0, 10 and 100 ppm temephos (determined chemically to contain less than 0.5, less than 0.5, 0.89, 6.0 and 59 ppm temephos, respectively) in an Abate® 4E formulation, were fed to mallard (Anas platyrhynchos) ducklings for 7 d. During this period, half of the ducklings in each dietary treatment group were housed in a heated brooder (39 to 41 °C) and half were housed in an unheated brooder (10 to 18°C). Mortality in all dietary groups in the unheated brooder was higher than in the heated brooder. High temephos-related mortality occurred in the 100 ppm group in the unheated brooder but not in any other diet-temperature groups. Ingestion of the 100 ppm temephos diet inhibited plasma Cholinesterase (ChE) activity and elevated plasma corticosterone concentration and creatine phosphokinase activity, but other selected plasma chemistries were not affected in a dose-related manner. Brain ChE activity was depressed only in the 100 ppm dietary groups; maximum inhibition of brain ChE activity was 48%. These findings suggest that diets containing up to 10 ppm temephos do not directly affect duckling survival during the first week of life and that the toxicity of 100 ppm temephos is markedly enhanced by cold.
Heavy metal tolerance and metallothionein induction in fathead minnows: Results from field and laboratory investigations
Authors: Benson William H. , Birge Wesley J. 
Published: March 2010

Abstract
Toxicity studies were performed on two natural populations of fathead minnows (Pimephales promelas). One group of organisms was taken from a metal-contaminated flyash pond associated with a coal-fired power plant and the other population was collected from Newtown hatchery ponds. As determined in acute toxicity tests, ash pond minnows were significantly more tolerant of cadmium and copper than were hatchery minnows. At an exposure concentration of 6.0 mg Cd/L in moderately hard water, the median period of survival (LT50) for flyash pond minnows was 50.0 h, compared with 6.8 h for hatchery minnows. The LT50 values for ash pond and Newtown animals exposed to 0.50 mg Cu/L in moderately hard water were 17.0 and 4.5 h, respectively. Both populations were about equally tolerant of zinc. After ash pond minnows were transferred to reconstituted water in the laboratory, tolerance to cadmium and copper decreased significantly after 7 d. Conversely, tolerance was increased in hatchery minnows following acclimation in the laboratory to sublethal concentrations of cadmium. For example, after exposing hatchery minnows for 35 d to 10 μg Cd/L, an acute toxicity test gave LC50 values of 2.88 and 1.71 mg Cd/L for acclimated and control organisms, respectively. This induced tolerance in cadmium-acclimated hatchery minnows was lost when organisms were transferred to cadmium-free water for 7 d. The results justify the conclusion that fathead minnows develop increased tolerance to cadmium and copper following prolonged sublethal exposure to these metals, and that this metal-induced tolerance is not sustained once organisms are removed from toxicant stress. As determined in biochemical studies, gill metallothionein concentrations followed the fluctuations in tolerance exhibited during cadmium acclimation and deacclimation. Thus, tolerance induction was, in part, attributed to increased production of metallothionein, a protein which selectively binds and deactivates cadmium, copper and certain other metals.
Solar radiation-induced toxicity of anthracene to Daphnia pulex
Authors: Allred P. M. , Giesy J. P. 
Published: March 2010

Abstract
Photoinduced anthracene toxicity to Daphnia pulex was investigated. Organisms were exposed to three nominal anthracene concentrations (3.0, 9.6 and 30.0 μg L−1) in static bioassays on clear, partly cloudy and cloudy days. A “shell coating” technique was used to achieve concentrations within the aqueous solubility range of anthracene and to obviate the need for a carrier solvent. Photoinduced anthracene toxicity was not observed under laboratory lighting conditions; it occurred only in the presence of solar radiation. A dose-response relationship existed for both anthracene concentration and solar radiation intensity. Anthracene was only slightly less toxic to organisms transferred into water containing no anthracene before exposure to solar radiation. This indicates that toxicity resulted from activation by solar radiation of material present on or within the animals and not in the water. Activation appeared to be of anthracene molecules and not anthracene degradation products, since similar concentrations of anthraquinone, the primary and most stable degradation product of anthracene, were not toxic at similar solar radiation intensities. Additionally, a series of filters was used to selectively remove UV wavelengths from solar radiation to determine the photoactive wavelengths. Mylar film absorbs in the UV-B region (285 to 315 nm) of solar radiation and Corning 0-52 glass absorbs essentially the entire spectrum of UV wavelengths (285 to 380 nm). Placement of Mylar film over bioassay beakers diminished photoinduced anthracene toxicity only slightly, whereas Corning 0-52 glass reduced toxicity proportionate to the reduction in UV intensity. Thus, wavelengths in the UV-A region (315 to 380) are primarily responsible for photoinduced anthracene toxicity.
Bioconcentration of naphthalene in tissues of the white mullet (Mugil curema)
Authors: Correa Manuel , Venables Barney J. 
Published: March 2010

Abstract
Naphthalene concentrations in the gill, liver, spleen and muscle of Mugil curema were measured before and after exposure to naphthalene concentrations of 0.01, 0.05 and 0.10 mg/L. Naphthalene was rapidly accumulated in M. curema tissues and the rate of uptake was much greater than the rate of depuration. The bioconcentration factor (BCF) ranged from 81 to 567 in muscle tissue and was inversely related to exposure concentration. The average BCF for muscle was closely estimated by an equation based on the n-octanol/water partition coefficient. The BCF was highest in the liver and spleen and lowest in muscle and gill tissues.
Hazards of chemicals to earthworms
Authors: Roberts Brian L. , Dorough H. Wyman 
Published: March 2010

Abstract
While great strides have been made in recent years regarding water quality criteria and hazard assessment of chemicals in the aquatic environment, the same is not true for the terrestrial ecosystem. This results in part from the magnitude of the problem and, perhaps, to some degree, from an attitude held by some that animals dwelling in and on the land can better cope with environmental stress than can their aquatic counterparts. Indeed, this sometimes may be the case, but results of our studies with the earthworm Eisenia foetida suggest otherwise. This organism is extremely susceptible to the toxic action of many common pesticides and other chemicals, and there is good evidence that this species is among the more hardy of all the earthworms. Although many facets of the terrestrial ecosystem must be addressed with regard to chemical hazards, practicality dictates that emphasis be directed toward specific organisms representing a given segment of the terrestrial population. This article discusses the vital role of earthworms in the environment and why they are particularly useful as test organisms, and summarizes chemical toxicity data obtained in laboratory and field investigations.