bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physical, chemical and physiological factors influencing entry of xenobiotics into the body via the pulmonary system
Authors: Lubawy William C. 
Published: March 2010

Abstract
The respiratory system has an extremely large surface area covered with a thin aqueous film of either mucus or a lipoprotein surfactant-containing fluid. The large total surface area and minute separation between the air space and the blood make the lung an efficient organ for the rapid, systemic absorption of xenobiotics with a variety of physicochemical characteristics.
Gases are absorbed throughout the entire respiratory system, the dominant driving force being diffusion. Highly water soluble gases are rapidly absorbed and may be cleared significantly through the surfaces of the upper respiratory tract before penetrating the deeper recesses of the lung.
Inhaled particles are deposited in the respiratory system according to their size. Particles with aerodynamic diameters of 5 to 30 μm are similarly trapped in the nasopharyngeal region; those from 1 to 5 μm are largely deposited in the tracheal and bronchiolar regions, the major portion of particles smaller than 1 μm penetrate to the alveoli.
Solute absorption studies indicate that the respiratory epithelium behaves like a lipoid–pore type membrane. Lipid soluble compounds are most rapidly absorbed at rates roughly related to their lipid/water partition coefficient at pH 7.4. Lipid insoluble substances are absorbed by nonsaturable diffusion with absorption rates related to the size of the molecules, i.e., the higher the molecular weight, the slower is the absorption. Organic ions can be absorbed by diffusion and by saturable, carrier-mediated processes. Pulmonary exposure to substances known to produce lung damage, i.e., ozone, silica, or acids, can alter carrier-mediated absorption of solutes and increase the passive absorption of lipid insoluble compounds alone or of both lipid soluble and lipid insoluble compounds.
Age appears to be an important factor in absorption rate of lipid insoluble compounds. The lungs of 3- to 12-day-old rats absorb lipid insoluble compounds twice as rapidly as those of 18- to 27-day-old or adult animals. Age is unimportant, however, in the absorption of lipid soluble compounds.
Species differences also exist for the absorption rates of lipid insoluble compounds but not for those of lipid soluble compounds. Mice will absorb lipid insoluble compounds 2 to 3 times more rapidly than rats, while rats absorb 1.3 to 3 times more rapidly than the rabbit.
Diagnosis of anticholinesterase poisoning in birds: Effects of environmental temperature and underfeeding on cholinesterase activity
Authors: Rattner Barnett A. 
Published: March 2010

Abstract
Brain cholinesterase (ChE) activity has been used extensively to monitor exposure to organophosphorus (OP) and carbamate (CB) insecticides in wild birds. A series of factorial experiments was conducted to assess the extent to which noncontaminant-related environmental conditions might affect brain ChE activity and thereby confound the diagnosis of OP and CB intoxication. Underfeeding (restricting intake to 50% of control for 21 d or fasting for 1–3 d) or exposure to elevated temperature (36 ± 1°C for 1 d) caused only slightreductions (10–17%)in brain AChE activity in adult male Japanese quail (Coturnix coturnix japonica). This degree of “reduction” in brain AChE activity is considerably less than the 50% “inhibition” criterion employed in the diagnosis of insecticide-induced mortality, but nevertheless approaches the 20% “inhibition” level used as a conservative estimate of sublethal exposure to a known insecticide application.
Predictability of chronic toxicity from acute toxicity of chemicals in fish and aquatic invertebrates
Authors: Kenaga Eugene E. 
Published: March 2010

Abstract
The relationship of the acute LC50 of chemicals to their chronic toxicity for aquatic animals can be expressed as the acute chronic ratio (ACR). Based on ACR data accumulated from the literature, the size ranges of ACRs for various chemicals were determined for different species. The relationship and significance of the size of the ACR for various species, LC50 values, bioconcentration factors, classes of chemicals and their uses and mode of toxic action are given. Eighty-six percent of the LC50 acute toxicity data were less than two orders of magnitude different from the chronic toxicity no-effect concentration for the same chemicals and species. Among the industrial organic chemicals (i.e., excluding pesticides and metals) the average ACR for four species of organisms was 12. Ninety-three percent of these ACR values were 25 or below. Industrial organic chemicals have a higher percentage of ACR values below 25 do than pesticides and heavy metals. These data offer a statistical basis for the prediction of chronic toxicity from acute toxicity.
Early life-stage toxicity test with tidewater silversides (Menidia Peninsulae) and chlorine-produced oxidants
Authors: Goodman Larry R. , Middaugh Douglas P. , Hansen David J. , Higdon Peggy K. , Cripe Geraldine M. 
Published: March 2010

Abstract
Early life-stage toxicity tests (continuous exposure from embryonic stage to 3 weeks or more into the exogenous feeding stage) with North American marine fishes have been conducted almost exclusively with cyprinodontids. In this report, we present methods for testing a representative of another family, Atherinidae. Embryos of the tidewater silverside Menidia peninsulae (Goode and Bean) were obtained by a laboratory spawning procedure that required lighting and tidal (current) stimuli. A 28-d toxicity test with chlorine-produced oxidants (CPO) began with stage 21 and 22 embryos (approximately 36 h old). Average measured CPO concentrations in exposure water were nondetectable (&lt; 0.01 mg/L) in the control and in the two lowest exposure concentrations, and 0.01, 0.04 and 0.21 mg/L. Survival of embryos to hatching averaged 99%, with no significant difference among treatments. Although no fish survived exposure to 0.21 mg CPO/L, survival was ≥ 88% in the control and the four other CPO treatments. Average wet weights of individual fish ranged from 11.7 mg in 0.04 mg/L to 13.2 mg in 0.01 mg/L, with no significant difference among treatments.
Brain cholinesterase activity and brain and liver residues in wild birds of a forest sprayed with acephate
Authors: Zinkl Joseph G. , MacK Paul D. , Mount Michael E. , Shea Patrick J. 
Published: March 2010

Abstract
In May 1981, acephate (O,S-dimethyl-acetylphosphoramidothioate) was applied at 0.85 kg [a.i. (active ingredient)]/ha in a ponderosa pine (Pinus ponderosa Douglas) forest of northern Arizona for suppression of a pandora moth (Coloradia pandora Blake) infestation. Brain cholinesterase (ChE) activity was determined in six species of wild birds, and brain and liver residues were determined in five species. Brain ChE was not inhibited on the day of spraying, but ChE was significantly inhibited 2 d after acephate application. The species of birds which presumably had the smallest territories and therefore would be more likely to be confined to the relatively small spray plots (about 250 ha) had the greatest ChE inhibition, both in magnitude and in numbers of birds with inhibition. Acephate and methamidophos (O,S-dimethyl-phosphoramidothioate) residues in brain and liver were highest on the day of spraying and decreased to undetectable concentrations 14 d after application. No correlation between brain ChE activities and brain or liver residue concentrations was found. The results of this study suggest that brain ChE inhibition found after acephate application is a better indicator of exposure than is tissue residue analysis. Brain ChE inhibition is probably due to a metabolite of acephate that is not detected by the methods used. Birds exposed to acephate in the wild may suffer as yet undetermined sublethal effects, but it is unlikely that acephate applied at 0.85 kg/ha or less will kill many birds.
Organic pollution and the macrobenthos of Raritan Bay
Authors: Stainken Dennis M. 
Published: March 2010

AbstractThe Raritan Bay—Lower New York Bay complex was surveyed to examine xenobiotic—sediment—benthic relationships. The macrofauna, sediment granulometry, extractable hydrocarbons, polychlorinated biphenyls (PCB) and polynuclear aromatic hydrocarbons (PAH) were surveyed concomitantly. PCB and PAH in molluscs and PAH in bottom waters were also measured.A total of 126 species was identified, principally molluscs, polychaetes and crustacea. Mya arenaria, Mercenaria mercenaria, Nereis virens and Glycera dibranchiata were the most abundant. Numerous xenobiotics were detected in the sediments and bivalves at all stations. Correlations of diversity indices, and numbers of bivalve species and polychaete species with specific sediment pollutants were poor or absent. Trends of decreasing diversity and density with increased pollution and/or silt-clay were observed, with more species generally occurring in the lower bay area. The dominant feature determining the distribution and abundance of the fauna appeared to be the sediment characteristics (substrate) and prevailing local currents within areas (zones) of the bay. These factors were further modified by the total hydrocarbon—xenobiotic loading of the sediments.
Sensitivity of agricultural ecological system models and implications for vulnerability to toxic chemicals
Authors: Kickert Ronald N. 
Published: March 2010

Abstract
Published results of sensitivity experiments on agricultural models by international authors are analyzed with a simple univariate sensitivity index. Values for system parameter and response-effects at ratios greater than 2.0 or 3.0 are presented for different crop plants, ecosystem components and processes. Responses are ranked according to their level of sensitivity to direct and indirect changes that conceivably could be imposed by manufactured chemicals. Of several hundred agricultural modeling publications, only 8.5% was found to contain results from sensitivity analysis experiments performed by their original authors. This low proportion means that environmental interactions and biological species other than those for which such results are published might be of equal or greater sensitivity and importance if comprehensive sensitivity analyses were available across all crops and ecological processes.
Results imply that hydrological flows, soil nutrient losses, and pesticide losses might all be quite vulnerable to disruption if indirect effects could be transferred through ecosystems by changes in weather and climate. Below-ground primary production processes in agroecosystems such as cotton, semiarid range pastureland, perennial ryegrass and sugar yield of sugar beets might be vulnerable to potential, direct, sublethal effects of chemical substances. If climatic processes were changed, indirect effects could be expected in cotton and pasture root growth, and potato yields. Results also indicate that vegetative growth of corn, alfalfa, soybean and perennial ryegrass might all be extremely vulnerable to any indirect effects from chemically induced climatic changes. Reproductive parts that could be especially vulnerable to possible potential direct effects from chemical substances include seed yield of annual semiarid pastures, fruit quality of hardwood trees and, specifically, apple fruit production. If any indirect effects are possible, it appears that grain sorghum and grain corn yields, and apple fruit yields might be very vulnerable. All these results are limited to the particular designs of the models used and the response variables on which data are available from simulations.
Partitioning of naphthalene, methylnaphthalenes and biphenyl between wastewater treatment sludges and water
Authors: Southworth George R. , Keller Jenny L. 
Published: March 2010

Abstract
Partition coefficients (Kp) describing the partitioning of naphthalene, methylnaphthalenes and biphenyl between organic-rich wastes and water were determined using 14C-tracer techniques as well as high performance liquid chromatographic analysis of the wastes and their aqueous extracts. Results of the two procedures were in good agreement. The concentrations of the specific organics in the wastes were not good predictors of concentrations in aqueous extracts, since Kp varied among the materials tested. Predictions of Kp based on organic carbon partition coefficient (Koc) and organic carbon content of the sludges were well below observed values. Oil content of the wastes and oil-water partition coefficients appeared to be important factors in determining Kp.
Derivation of site-specific water quality criteria for cadmium and the St. Louis River Basin, Duluth, Minnesota
Authors: Spehar R. L. , Carlson A. R. 
Published: March 2010

Abstract
Several freshwater aquatic species were exposed to cadmium in site and laboratory water to evaluate a protocol recommended by the U.S. Environmental Protection Agency for deriving site-specific water quality criteria. The recalculation, indicator species and resident species procedures of this protocol were used to modify the national cadmium criteria. These procedures were used to account for differences in species sensitivity and in the biological availability and/or toxicity of cadmium due to physical and/or chemical characteristics of the site water.
The site-specific maximum concentration derived from the recalculation procedure was slightly lower (1.3 as compared with 2.2 μg/L) than the national criterion. The maximum concentration derived from the indicator species procedure was 7.0 μg/L and was calculated by using a water effect ratio from tests conducted in both site and laboratory water. Acute tests with several species demonstrated that cadmium was less toxic in site water than in laboratory water. The site-specific maximum concentration derived from the resident species procedure (from eight species exposed to cadmium in site water) was 1.9 μg/L. The 30-d average concentrations were the same as the maximum concentrations in the procedures in which the national acute/chronic ratio was used in the calculation. These concentrations were much lower when the site-specific acute/chronic ratio was applied.
Acute tests conducted monthly in site water showed that cadmium toxicity varied by more than a factor of 3 over the year. This indicates the need for considering seasonal changes in physical and chemical characteristics of the site water when deriving criteria to protect aquatic life.
Toxicity of ammonia to early life stages of the smallmouth bass at four pH values
Authors: Broderius Steven , Drummond Robert , Fiandt James , Russom Christine 
Published: March 2010

AbstractEarly life stages of smallmouth bass (Micropterus dolomieui Lacepede) were exposed to ammonia concentrations at four different pH values (from 6.5 to 8.7). Acute lethal tests were conducted with juveniles, and partial chronic tests were initiated at the late embryo stage and extended through 32 d of exposure.The 96-h LC50 ammonia concentrations at pH 6.53, 7.16, 7.74 and 8.71 were 371, 117, 39.5 and 7.43 mg/L total ammonia-N (NH3-N) and 0.694, 1.00, 1.20 and 1.78 mg/L un-ionized NH3, respectively. The acute toxicity of ammonia in terms of NH3-N was directly related to test pH, and in terms of NH3 was inversely related to pH.Embryo through preswim-up larvae were the most resistant early life stages studied during chronic exposures. Survival of embryos to larvae 7 d post hatch was unaffected by ammonia concentrations ranging from 0.236 to 0.865 mg/L NH3 at pH values of 6.60 to 8.68. Adverse effects on early developmental stages demonstrated that survival to 14 d and growth to 32 d were among the most sensitive indicators of ammonia toxicity. The estimated 32-d no-observed-effect concentrations, defined as the geometric means of the maximum no-effect and minimum effect concentrations determined from statistically significant decreases in growth (wet weight), were calculated to be 17.4, 14.4, 14.6 and 2.40 mg/L total NH3-N and 0.0437, 0.148, 0.599 and 0.612 mg/L un-ionized NH3 at pH values of 6.60, 7.25, 7.83 and 8.68, respectively. The acute to chronic ratios, as calculated from NH3 concentrations and acute results adjusted to the above pH values for chronic tests, were 16.7, 7.03, 2.07 and 2.89, respectively.
Modification of the neubauer technique to assess toxicity of hazardous chemicals in soils
Authors: Thomas J. M. , Cline J. F. 
Published: March 2010

Abstract
The Neubauer technique was modified to provide a sensitive and economical phytoas-say for soils and surface waters obtained from a chemical waste site. Use of individual plastic enclosures allowed safe handling and disposal over the course of our experiments. Laboratory tests showed that water from a holding basin was toxic to wheat plants at dilutions of less than 1% and that our modified Neubauer technique produced results compatible with both pot culture and the standard Neubauer test. Further testing of several inorganic constituents of the basin water pointed to an organic toxicant, even though the original water contained high levels of sodium, copper and other elements.
The results of testing 26 samples from an abandoned waste pond were negative insofar as toxicity to wheat and lettuce seeds, whereas samples from an abandoned ditch allowed us to determine areal toxicity as well as toxicity as a function of depth and suggested that more than one species should be tested.
Quantitative structure-activity relationships in aquatic toxicity studies of chemicals and complex mixtures of chemicals
Authors: Hermens Joop , Musch Aalt , Köunemann Hans , Leeuwangh Peter 
Published: March 2010

Abstract
Several quantitative structure-activity relationships (QSARs) are presented that describe the aquatic toxicity of three different groups of organic chemicals. In QSARs for nonreactive organic chemicals, hydrophobicity as the only parameter gives excellent results. For anilines, hydrophobicity and the Hammet constant were used for the QSAR, whereas for reactive organic halogen compounds, the aquatic toxicities correlated very well with the chemical reactivities. In addition, some remarks on the applicability of QSARs are made.
Water solubility behavior of binary hydrocarbon mixtures
Authors: Burris David R. , Macintyre William G. 
Published: March 2010

Abstract
The aqueous solubility equilibrium behavior of seven medium molecular weight, liquid, binary hydrocarbon mixtures has been determined at 20°C. Binary hydrocarbon mixtures containing structurally similar compounds exhibited ideal solution behavior, but deviations from ideality by as much as a factor of 2.5 at 0.1 mole-fraction occurred with aromatic-aliphatic mixtures. The ratio of concentrations of hydrocarbon solutes appears to be independent of the degree of saturation of the binary hydrocarbon mixture with water. This independence implies that the equilibrium phenomena observed could be applicable under nonequilibrium conditions.
Metabolic diversity and activity of heterotrophic bacteria in ground water
Authors: Ventullo Roy M. , Larson Robert J. 
Published: March 2010

Abstract
The number and metabolic diversity of bacteria were studied in groundwaters collected in the United States and Canada. Bacterial numbers were determined by acridine orange direct counts, viable plate counts and 14C most-probable-number counts. Metabolic diversity was determined by heterotrophic activity and biodegradation potential assays using several classes of natural and xenobiotic substrates. Rates of metabolism in diversity studies (uptake and/or mineralization to carbon dioxide) were measured by radiotracer techniques and rate data were analyzed by nonlinear regression models to generate appropriate kinetic constants. Overall, the density and activity of groundwater bacteria were comparable to values reported for oligotrophic marine and freshwater systems. Bacterial numbers ranged from approximately 102 to 106 cells/ml, depending on the enumeration technique used and the particular sample tested. Turnover times for natural compounds in heterotrophic activity assays (i.e., glucose, amino acids) ranged from less than 100 to more than 2,000 h. Degradation half-lives for xenobiotic and natural substrates in biodegradation potential studies exhibited a comparable range of values. In general, our results indicate that groundwater bacteria have the potential to metabolize several classes of natural and xenobiotic substrates, although at reduced rates compared with those of surface water systems.
Ration and toxicant preexposure influence dieldrin accumulation by rainbow trout (Salmo gairdneri)
Authors: Shubat Pamela J. , Curtis Lawrence R. 
Published: March 2010

Abstract
Whole body accumulation and tissue distribution of dieldrin in rainbow trout were studied through oral-dose disposition tests and subchronic exposures via water (0.04 and 0.08 μg dieldrin/L) and/or diet (0.087 μg dieldrin/g fish/d). Growth and no-growth (maintenance) rations of 4 and 2% body weight per day were employed. In subchronic tests, apparent steady-state residue concentrations depended on ration and exposure concentration after 8 weeks of exposure. At 16 weeks, mean whole fish residue concentrations ranged from 120 to 1,400 ng dieldrin/g fish. Combination food and water exposures at a growth ration produced the highest accumulation values (1,300–1,400 ng dieldrin/g fish). Maintenance rations apparently limited accumulation to a maximum of 360 ng dieldrin/g fish. Whole body dieldrin concentration, calculated on the basis of total lipids, greatly reduced the differences in residue levels due to ration.
Tissue distribution of a single oral dose of [14C]dieldrin was determined in naive (no pretreatment) fish and those preexposed via the diet for 2, 4 or 6 weeks. Tissue concentrations of the tracer dose were determined 48 h following administration. Retention of the [14C]dieldrin was similar in most tissues of naive, 2- or 6-week dieldrin-pretreated fish with a slight downward trend with duration of pretreatment. Retention of 14C in the bile of fish receiving maintenance and growth treatments increased two- and five-fold, respectively, in 6-week pretreated as compared with naive fish. After 4 weeks of pretreatment, 14C concentrations peaked in all tissues except the bile, gut, and gut contents.
Patterns of metal pollution in soils: A comparison of the values obtained by atomic absorption spectrophotometry and x-ray fluorescence
Authors: Smith G.H. , Lloyd O. Ll. 
Published: March 2010

Abstract
In the town of Armadale in central Scotland, where high rates of mortality and high birth sex ratios (males/females) have been observed, the main industry is steel production. Previous studies have shown a geographical relationship between the foundry, air pollution by metals as measured by low-technology biomonitors, and the epidemiological abnormalities. In this study, the patterns of pollution in Armadale were investigated by taking soil cores from 29 sites within the town. The concentrations of metals in all samples were measured by means of atomic absorption spectrophotometry, and 19 of the samples were analysed using x-ray fluorescence. The results extended the knowledge about the pattern of pollution in Armadale, and also allowed the direct comparison of these two methods of analysis in a study of soil pollution.