bluuebunny/crossref_metadata_2025_split huggingface dataset:
Do structure-activity relationships for the acute toxicity of pcbs and pbbs also apply for induction of hepatocellular carcinoma?
Authors: Robertson L. W. , Silberhorn E. M. , Glauert H. P. , Schwarz M. , Buchmann A. 
Published: March 2010

Abstract
Studies of the carcinogenic activity of commercial polychlorinated biphenyl (PCB) and polybrominated biphenyl (PBB) formulations in rodents have shown that (a) when given at appropriate doses and for extended periods of time, PCB and PBB mixtures cause preneoplastic lesions and carcinomas; (b) cancerous lesions are confined principally to the liver; (c) there is a marked trend from enzyme-altered foci to neoplastic nodules to hepatocellular carcinoma with time; and (d) PCB mixtures with high chlorine content are more potent in causing hepatocellular carcinoma than mixtures with low chlorine content. Practically no data are available on the activity of individual PCBs or PBBs as carcinogens; however, considerable data exist on the activity of congeneric PCBs and PBBs as promoters/initiators of two-stage hepatocarcinogenesis in the rat. The compounds studied were either acutely toxic (coplanar) biphenyl congeners, nonacutely toxic congeners or halogenated biphenyls with intermediate acute toxicity. Acutely toxic PCBs/PBBs as well as those without acute toxicity and those with intermediate toxicity may all promote hepatocarcinogenesis in the rat, but probably by different mechanisms. The ability of congeneric PCBs and PBBs to stimulate cellular growth and division (mitogenic effects) on the one hand and/or hepatotoxic effects on the other most likely contributes to the carcinogenic effects seen. We assert that the assessment of risk for PCB/PBB exposure must take into account the potential long-term toxic effects of exposure to all three groups of polyhalogenated biphenyls.
Long-term neurobehavioral effects of perinatal polychlorinated biphenyl (PCB) exposure in monkeys
Authors: Schantz Susan L. , Levin Edward D. , Bowman Robert E. 
Published: March 2010

Abstract
In recent years, there has been growing concern about the potential long-term neurobe-havioral effects of perinatal polychlorinated biphenyl (PCB) exposure. We have addressed this issue in a series of studies at the Harlow Primate Laboratory. Offspring of rhesus monkeys (Macaca mulatto) exposed to commercial PCB mixtures (Aroclor 1016 or Aroclor 1248) were tested on two-choice discrimination-reversal learning at 1.5 years of age and on delayed spatial alternation, a spatial learning and memory task, at four to six years of age. Deficits in performance were observed on both tasks. The deficit observed on delayed spatial alternation in Aroclor 1248-exposed monkeys was quite dramatic. The monkeys were tested for 80 test sessions, but were never able to achieve control levels of performance. This effect was observed when the monkeys were four to six years of age (young adulthood), even though they had not been exposed to PCBs since they were weaned at four months of age. The pattern of effects on both discrimination-reversal learning and delayed spatial alternation was suggestive of damage to the prefrontal cortex.
On-site methods for assessing chemical impact on the soil environment using earthworms: A case study at the baird and McGuire Superfund Site, Holbrook, Massachusetts
Authors: Callahan Clarence A. , Menzie Charles A. , Burmaster David E. , Wilborn David C. , Ernst Theodore 
Published: March 2010

Abstract
Five Lumbricus terrestris Linneaus were placed into enclosures at a field site and evaluated after 7 d. The enclosures were distributed in transects throughout areas of high and low contamination and in a reference area. Observations of earthworm responses for mortality, morbidity (coiling, stiffening, swelling, lesions) and whole body burden were compared to chemical measurements in corresponding soil samples. Nine chemicals (DDT, DDE, DDD, α-chlordane, γ-chlordane, chlordene, γ-chlordene, endrin, nonachlor) were measured in the whole body of earthworms and soil samples. Various levels of impact were described by scoring earthworm responses from sampling locations throughout the field site. A ranking of the sample locations from low to high impact by the earthworm response variables is directly correlated to the ranking of these locations for concentrations of total chlordane and total DDT in corresponding soil samples. Results show acute toxicity to earthworms placed on-site and suggest that whole body concentrations could impact earthworm predators. In addition, the on-site method eliminates the need to transport soils to off-site laboratories, thus preventing subsequent disposal issues.
The solubility of hydrophobic aromatic chemicals in organic solvent/water mixtures: Evaluation of four mixed solvent solubility estimation methods
Authors: Dickhut Rebecca M. , Armstrong David E. , Andren Anders W. 
Published: March 2010

Abstract
The solubility of benzene, naphthalene and phenanthrene, in miscible organic solvent/water mixtures was evaluated using four mixed solvent solubility estimation methods. In methanol/water and ethanol/water systems, solubility behavior of hydrophobic aromatic solutes (naphthalene and phenanthrene) is accurately predicted by assuming that the organic cosolvent and water behave as an ideal or regular mixture. Benzene solubility in ethanol/water mixtures is not accurately predicted with the ideal solvent mixture assumption, possibly as the result of nonideal solution behavior due to solute-solute interactions. In 1-propanol/water and acetone/water mixtures, hydrophobic solute solubility is not adequately predicted with the mixed solvent solubility models.
Fate of commercial disperse dyes in sediments
Authors: Yen C-P. C. , Perenich T. A. , Baughman George L. 
Published: March 2010

Abstract
Kinetics of disappearance of seven different disperse dyes were determined in compacted sediments at room temperature. The commercial dyes (in dispersed solid form) were representative of nitroazo, anthraquinone, and quinoline structures that are widely used. Reaction rates were found to be first order over at least two half-lives and were different for the three groups of dyes. Half-lives were on the order of hours, days, and months for the nitroazobenzene, aminoanthraquinone, and quinoline dyes, respectively. Stability of the latter is consistent with detection of a quinoline dye in treatment plant sludge and in sediment from a water body receiving treated effluent. The azobenzene dyes are degraded by cleavage of the azo group to give anilines and ring-substituted phenylenediamines from the diazo component of the molecule. Products from the other portion (coupling component) of the molecule are unidentified, as yet, but are expected to be N, N-disubstituted phenylenediamines. Products of the anthraquinone dyes were unidentified, except for the case of a nitrated dye on which the nitro group was reduced.
Genotoxicologic evaluation of ozonated/chlorinated drinking water: Cytogenetic effects of XAD-fractions on cultured human cells
Authors: Varga Csaba 
Published: March 2010

Abstract
Ozonated and chlorinated drinking water produced by a surface water treatment plant was examined to determine if genotoxins were formed by the treatment process The examined technology included ozonation (oxidation) and chlorination (disinfection), but excluded granular activated carbon or slow sand filtration following the ozonation step Investigations involved cytogenetic assays, chromosomal aberration, and sister chromatid exchange (SCE) analyses of 70-h human peripheral lymphocyte cultures treated with water isolates obtained on XAD resins Neutral XAD 2/4, XAD-8, and acidic XAD-2/4–8 fractions were tested separately in 1-, 10-, 20-μl/ml concentrations of the 7,000-fold isolates without metabolic activation A weak but significant (p &lt; 0.05) SCE-inducing activity could be detected only upon treatment with the neutral XAD-2/4 fraction Clastogenicity and mitotic inhibition were not observed in the given concentration range
Bacterial mutagenicity and acute toxicity of solvent and aqueous extracts of soil samples from an abandoned chemical manufacturing site
Authors: Donnelly K. C. , Brown K. W. , Anderson C. S. , Thomas J. C. , Scott B. R. 
Published: March 2010

Abstract
Using a grid pattern, a total of 50 soil borings (DCT 1 through DCT 50) were collected from an abandoned chemical manufacturing facility. Split samples were obtained from six cores collected from a centralized location near a former wastewater lagoon. An additional sample from the 2.1- to 2.4-m depth of core DCT 20 was obtained as representative of the waste present on site. Three subsamples from each of the six cores or a total of 18 samples were sequentially extracted with methylene chloride and methanol for testing in mutagenicity and acute toxicity assays. A separate batch extraction with water was conducted and evaluated, using both chemical and biological test methods. The maximum mutagenic response was 3,237 net revertants induced with metabolic activation by 1 mg of the methanol extract of the 0- to 0.6-m depth at sampling location DCT 32. The water extract of the 0- to 0.6-m depth at sampling location DCT 32 induced 737 net revertants per mg. At sampling location DCT 24, the water extract induced 0.74, 1.32, and 2.5 toxic units in the Microtox® assay and 935, 69, and 39 net revertants per mg in the mutagenicity assay at the 0- to 0.3-, 1.2- to 1.4-, and 2.1- to 2.4-m depths, respectively. The chemical analysis of the samples from location DCT 24 indicated that the concentration of 2,3,6-trichlorobenzene acetic acid ranged from 16 ppm in the 0- to 0.3-m depth and to 0.95 ppm and below the detection limits at the 1.2- to 1.4- and 2.1- to 2.4-m depths. The methanol extract of the soil from the 0- to 0.3-m depth induced 19.2 toxic units in the acute toxicity assay and 1,467 net revertants in the mutagenicity assay. These results suggest that the most accurate site assessment is obtained when a water extract is evaluated to measure leaching potential and a solvent extract is evaluated to determine the relative total hazard of the sample. In addition, the combined use of chemical analysis, mutagenicity, and acute toxicity bioassays provides more accurate information from which to make a risk assessment.
Ammonia toxicity to macrophytes (common duckweed and rice) using static and renewal methods
Authors: Wang Wuncheng 
Published: March 2010

Abstract
Ammonia is a widespread contaminant that occurs in municipal wastewaters, industrial wastewaters, and agricultural wastes. Most ammonia toxicity studies deal with species of fish and macroinvertebrates, but very little information is available on ammonia phytotoxicity. The objectives of this study were to compare ammonia toxicity by using static and renewal methods and to compare phytotoxicity tests by using the vascular plants common duckweed and rice. Un-ionized ammonia-N at the rate of 8.85 mg/L inhibited rice seedling growth by 27%, using the renewal method, whereas the same amount caused insignificant effects on rice growth, using the static method. Ammonia-N at up to 8.85 mg/L did not inhibit duckweed growth, using the static method. By using the renewal method, un-ionized ammonia-N at concentrations greater than 3.0 mg/L depressed duckweed growth noticeably (20% or more). The increased ammonia concentration inhibited duckweed growth correspondingly, producing a linear relation for the concentration-inhibition effect. An un-ionized ammonia-N concentration of 7.16 mg/L was calculated to cause 50% duckweed growth inhibition (IC50), and 95% confidence limits ranged from 6.33 to 8.47 mg/L.
Effect of exposure time on the acute toxicities of permethrin, fenitrothion, carbaryl and carbofuran to mosquito larvae
Authors: Parsons J. T. , Surgeoner G. A. 
Published: March 2010

Abstract
Static toxicity tests were used to assess the acute toxicity to third-instar Aedes aegypti (L.) to short-term exposures of five insecticides (technical permethrin, microencapsulated permethrin, fenitrothion, carbaryl, and carbofuran). Larvae were exposed to each insecticide for times of 0.25, 0.5, 1, 2, 4, 8, or 24 h, then transferred to clean water and reared to the adult stage. Technical permethrin was most toxic to Aedes aegypti, followed by fenitrothion, microencapsulated permethrin, carbofuran, and carbaryl (24 h LC50 values, based on survival to the adult stage, were 0.45, 3.1, 21.6, 90.0, and 510.0 μg/L, respectively).
Acute toxicity increased with increasing exposure time to all five insecticides. However, the relationship between exposure time and acute toxicity differed among insecticides. The increase in acute toxicity was greater over short than over long exposures for technical permethrin, carbaryl, and carbofuran (LC50 values decreased 11.2 to 22.4-fold over a 0.5- to 4-h exposure, and 2.6- to 5.2-fold over a 4- to 24-h exposure). The opposite was true for microencapsulated permethrin (LC50 values decreased 3.6-fold over a 0.5- to 4-h exposure, and 6.2-fold over a 4- to 24-h exposure). Acute toxicity to fenitrothion increased proportionately with increasing exposure time.
Some larvae recovered from immobilization following short (0.5- to 4-h) exposures to technical permethrin, microencapsulated permethrin, carbaryl, and carbofuran (EC50 values based on immobilization immediately after exposure terminated were 0 to 15 times lower than corresponding LC50 values). However, ability to recover decreased with increasing exposure time such that no recovery from immobilization occurred after 8 or 24 h exposure. Larvae did not recover from immobilization following exposure to fenitrothion. These results indicate the need for a postexposure observational period to fully assess acute toxicity following exposure to insecticides.
Environmental factors correlated to dichlorophenol dechlorination in anoxic freshwater sediments
Authors: Hale Dorothy D. , Rogers John E. , Wiegel Juergen 
Published: March 2010

Abstract
The reductive dechlorination of three dichlorophenol (DCP) isomers was studied in anoxic sediments collected every other month for a year from five sites in one pond. Several physical, chemical, and microbiological characteristics of the sediments also were determined to identify correlations with DCP dechlorination that may be used to predict the persistence of these compounds in anoxic sediments. Stepwise regression indicated that for 2,5- and 3,4-DCP, sediment pH, redox potential (Eh), and concentration of sulfate and nitrate accounted for 83% of the variation in T50 values (time for dechlorination of 50% of a DCP to a monochlorophenol). Although the number of sediment microorganisms that dechlorinate 2,4-DCP varied two orders of magnitude in sediments collected during the study year, regression analysis indicated that neither this nor any other variables could account for greater than 50% of the variation in T50 values for 2,4-DCP. Chlorine was preferentially removed from the aromatic ring in the order ortho &gt; para &gt; meta; however, the influence of chlorine position on the ring on the persistence of the DCPs was generally not statistically significant.
Distribution of cadmium in an octanol/water system in the presence of xanthates and diethyldithiocarbamate
Authors: Block Mats 
Published: March 2010

Abstract
The octanol/water partition coefficient of cadmium was measured in the presence of ethyl-, isopropyl-, isobutyl-, and amylxanthates and diethyldithiocarbamate. For each complexing agent, the threshold concentration at which hydrophobic cadmium complexes started to appear was established. Cadmium was shown to form hydrophobic complexes with xanthates and diethyldithiocarbamate (maximal log POW = 1.73–2.64) at total ligand concentrations of 10−6 to 10−1 M. The proportion of cadmium in the octanol phase began to increase within the range of approximately 10−6.5 to 10−6 M for xanthate and approximately 10−5.0 M for diethyldithiocarbamate.
Effect of carbon-rich waste materials on movement and sorption of atrazine in a sandy, coarse-textured soil
Authors: Guo Lei , Bicki Thomas J. , Hinesly Thomas D. , Felsot Allan S. 
Published: March 2010

Abstract
Soil columns were used to investigate leaching of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] in a Plainfield sandy soil amended with waste activated carbon (WAC), digested municipal sewage sludge (DMS), or animal manure. Lower amounts of atrazine were consistently observed in leachates from soil with amendments than from soil without amendments. Ability of the three wastes to reduce leaching of atrazine followed the order WAC ≫ DMS &gt; animal manure. Atrazine recovery in leachate ranged from 0.1% from soil amended with WAC at 2.1 t of total carbon per ha (t C/ha) to 77.4% from unamended soil. Mobility of atrazine in amended soil was inversely related to its sorption coefficient, KOC. Reduction in amount of leached atrazine by application of DMS or manure may also have involved increased degradation and/or formation of bound residues. Findings of this study provide basic information for possible utilization of waste materials in coarse-textured soils to reduce leaching of pesticides to ground water.
Chromosomal aberrations in native small mammals (peromyscus leucopus) at a petrochemical waste disposal site: II. Cryptic and inherited aberrations detected by G-band analysis
Authors: Mcbee Karen 
Published: March 2010

Abstract
Wild rodents (Peromyscus leucopus) collected from a hazardous waste site polluted with petrochemicals and known to have significantly increased frequencies of somatic chromosome aberrations in a standard metaphase chromosome aberration (SMCA) assay were examined by G-banding, a differential staining technique. Several classes of aberrations not detectable with SMCA were identified, including Robertsonian fusions, pericentric and paracentric inversions, and interstitial deletions. Four classes of these more cryptic aberrations were significantly higher in animals from the hazardous waste site compared to animals from reference sites. Several animals also carried apparently inherited aberrations in chromosomes 5, 10, and 21, suggesting that aberrations induced in a parent may be transmitted to offspring. When all classes of aberrations were converted to numbers of lesions per cell, animals from the hazardous waste site did not show elevated frequencies of lesions or aberrant cells, compared to animals from reference sites, unless inherited aberrations were removed from the data set. Then animals collected from the hazardous waste site showed a significantly increased number of aberrations per cell. Two chromosomes (5 and 21) sustained more aberrations than the other members of the complement, suggesting that some chromosomes may be more susceptible to induced damage than others. The method of G-banding itself may obscure much of the damage attributable to single chromatid breaks in SMCA but reveals types of damage not detectable in SMCA, indicating that the application of any single genetic assay technique may seriously underestimate actual levels of induced damage in exposed organisms.
Uptake and elimination of radioactivity from rainbow trout (oncorhynchus mykiss) following exposure to [14C-ring]-2-phenyldodecane
Authors: Burke Alison B. , Millburn Peter , Huckle Keith R. , Hutson David H. 
Published: March 2010

Abstract
The bioconcentration and elimination of radioactivity was monitored in rainbow trout exposed to [ring-14C]-2-phenyldodecane in a flow-through system. The uptake of radioactivity from the water at 15°C into the tissues was rapid, with equilibrium concentrations being approached at about 10 d. The bioconcentration factor (BCF) (Cfish/Cwater) measured in whole fish was 443. After 28 d exposure, fish were transferred to tanks containing clean water, and the clearance of radioactivity from tissues was monitored for a further 28 d in two test groups; one was maintained on a growth diet and the other on a rationed feed. Radioactivity was cleared rapidly from fish in both groups. Bile was a significant route of elimination. The effect of temperature was studied. When fish were exposed at a water temperature of 4°C, less [14C]-2-phenyldodecane was taken up, giving a lower BCF value for radioactivity (149) than the level at 15°C. The higher BCF at 15°C was due to the greater effect of temperature on uptake (k1 values) than on the elimination (k2 values). The BCF value predicted for 2-phenyldodecane based on water solubility or partition coefficient data is between 20,000 and 3,500,000. However, 2-phenyldodecane is susceptible to rapid and extensive biotransformation by fish. This metabolism limits the bioconcentration of the detergent alkylate in fish tissues.
Use of small artificial ponds for assessment of hazards to aquatic ecosystems
Authors: Heimbach Fred , Pflueger Wolfgang , Ratte Hans-Toni 
Published: March 2010

Abstract
Field tests with natural ponds often lack sufficient replication and/or control, making interpretation and evaluation of results difficult. For the assessment of potential hazards of chemicals to aquatic ecosystems, small artificial ponds have become increasingly valuable. Artificial pond ecosystems should, as far as possible, reflect natural conditions, contain all trophic levels with a high diversity of organisms, and, most importantly, be logistically and experimentally manageable. To fulfill these conditions, 5-m3-volume ponds, interconnected by closable locks, were provided with natural lake sediment and well water. Caged fish were added to each pond, and the interconnecting locks were kept open until identical physicochemical and biological conditions had been established. At this time, the ponds were isolated from one another and experiments with a pyrethroid insecticide (Baythroid®) containing cyfluthrin as the active ingredient (a.i.) were conducted. The results of these field tests, which include both the fate and the biological effects of the insecticide, were compared with data obtained in larger natural ponds. Overall, the results were similar, indicating that useful information on the potential hazard of chemicals can be obtained in small artificial ponds.
Statistical treatment of data from microbial toxicity tests
Authors: Nyholm Niels , Sørensen Per Settergren , Kusk K. Ole , Christensen Erik R. 
Published: March 2010

Abstract
The response measured in microbial toxicity tests is typically a continuous variable, and the associated error is an experimental error related to the physical measurement of the response and to handling differences between experimental units (e.g., test flasks). The traditional statistical theory for treating quantal (or categorical) data from tests with animals is based on the concept of a tolerance distribution for individual test subjects that is not appropriate for microbial tests. Data from microbial tests should be dealt with by conventional curve-fitting techniques without any confusion with tolerance distributions. Using an empirical mathematical function that describes a sigmoid curve, concentration–response curves can be fitted by nonlinear regression directly onto the data or by weighted linear regression after a linear transformation of the data. Calculation of confidence intervals around the estimated EC figures (calculated effective concentrations that cause a certain percentage of inhibition; for example, EC10 for 10% inhibition) is less complicated with weighted linear regression on transformed data than it is with nonlinear regression. The paper provides a general discussion of the problem of analyzing data from microbial toxicity tests and gives some examples of feasible methods.