bluuebunny/crossref_metadata_2025 huggingface dataset:
Organizing data for environmental studies
Authors: Neely W. Brock
Published: March 2010

Using the vapor pressure, water solubility and molecular weight of a chemical, the partitioning of that chemical between the major environmental compartments can be quickly assessed. Thus it is possible to estimate what percentage of the chemical will be located in the ground, bottom sediments, water and air. Combining this information with a knowledge of the known degradation rates an estimation of the relative persistence of the chemical can be made. The technique is illustrated by ranking 84 of the 119 priority pollutants according to their potentials for contaminating water. A final example demonstrates how the model may be used to identify the potential environmental impact of a new chemical.
Pesticides in agricultural runoff and their effects on downstream water quality
Authors: Willis Guye H. , McDowell Leslie L.
Published: March 2010

Agricultural use of pesticides has remained high for economic reasons. Because aquatic species may bioaccumulate pesticides more readily than terrestrial organisms, there has been much concern about pesticides in agricultural runoff. Despite this concern, there presently is little relevant information for use in making accurate predictions of the impact of specific pesticide amounts in agricultural runoff on water quality at some point downstream. There is a compelling need for fundamental research on the physical, chemical, biological and hydrological processes that regulate pesticide behavior not only in agricultural and aquatic habitats, but also during transit between the two. Further, data are needed concerning pesticide toxicity potential as a function of the aquatic physical and chemical regime, and concerning population recovery dynamics as a function of pesticide concentration and species stress.
Fate of lindane in the aquatic environment: Rate constants of physical and chemical processes
Authors: Saleh Farida Y. , Dickson Kenneth L. , Rodgers John H.
Published: March 2010

Water solubility, hydrolysis and photolysis rate constants, and sorption-desorption partition coefficients were determined for lindane in three different natural water-sediment systems, as well as in a Milli-Q water and montmorillonite clay system. The aqueous solubility of lindane in surface waters at 25 ± 1°C ranged from 7.9 to 8.4 mg/L. In Milli-Q water, lindane solubility was 9.2 mg/L. At α = 0.05, no significant difference was found between the values in different natural waters; however, the Milli-Q water solubility did differ statistically. Lindane hydrolysis was found to be catalyzed by hydroxide and hydrogen ions. Neutral hydrolysis was relatively unimportant. Hydrolysis data followed first-order kinetics with kh values of 74 × 10−4 h−1 at pH 9 and 7.4 × 10−1 h−1 at pH 5. Experimental hydrolysis half-life (t1/2) in natural waters of pH 9.3 was comparable to the calculated value (92 h). Other natural water systems of pH 7.3 and 7.8 had t1/2 values greater than calculated values. Adjusted mid-winter photolysis half-life of lindane in Milli-Q water was 1.56 × 103 h. Photolysis rate enhancement was noted in natural water of pH 9.3, possibly due to the alkaline hydrolysis side reaction. Photolysis rate retardation was noted in natural water of pH 7.3 and 7.8. Sorption-desorption coefficient in Milli-Q water-montmorillonite clay was 1,259. Sorption coefficients for the natural systems ranged from 56 to 2,238. Results of the sorption-desorption experiments indicate that the wide diversity of the characteristics of the natural water sediment systems considerably affect the lindane sorption-desorption behavior.
The absence of hepatic cellular anomalies in TCDD-exposed beach mice — a field study
Authors: Cockerham Lorris G. , Young Alvin L.
Published: March 2010

Quantitative ultrastructural studies were conducted on liver tissue from beach mice, Peromyscus polionotus, exposed to the toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in a field environment. Hepatic tissue from 30 animals was examined for changes in smooth endoplasmic reticulum, rough endoplasmic reticulum and mitochondria. Fifteen animals were collected from a unique military test site in northwest Florida, where they had been continuously exposed to soil levels of < 10 to 710 parts per trillion (ppt) TCDD. The remaining animals were from a control field not exposed to TCDD. All tissue was examined both histopathologically and by an ultrastructural stereological technique.

The mean levels of TCDD in composite liver samples from exposed mice collected in the field varied from 960 ppt for females to 1,300 ppt for males. The levels of TCDD in the livers of the beach mice collected from the field substantiated the bioaccumulation of TCDD. Although the levels of TCDD in the livers were greater than those found in the soil, TCDD was not detected in the portion of the food chain consisting of seeds.

No significant histopathological or ultrastructural changes were found in hepatic parenchymal cells after long-term, low-level exposure to TCDD in the field. The levels of TCDD encountered in this study, though much lower than those normally found in most laboratory experiments, are far greater than the estimated concentrations in the environment, or in animal tissues after normal application of the herbicide 2,4,5-T.
Alternative models for describing the bioconcentration of organics in fish
Authors: Spacie Anne , Hamelink Jerry L.
Published: March 2010

The accumulation of organic residues in fish is the result of competing rates of uptake and elimination, which can be modeled by pharmacokinetic techniques. Although first-order kinetics are usually assumed, they are rarely verified. Models with biphasic, second-order or Michaelis-Menten kinetics may prove to be better choices, depending on exposure level and mode of elimination. The well-known correlation between bioconcentration factor and partition coefficient (P) derives from separate correlations for the uptake and elimination rate constants with P. While such correlations appear to be linear in the range of log P = 2–5 for organics that are not metabolized, they sometimes fail at higher values of log P. A drug transport model is proposed to account for the “non-ideal” bioconcentration of a variety of organics in fish. According to this model, uptake is a nonlinear function of partition coefficient, water solubility and membrane permeability.
Environmental safety assessment of dipropylene glycol dibenzoate
Authors: Butz Robert G. , Atallah Yousef H. , Yu Ching C. , Calo Charles J.
Published: March 2010

Dipropylene glycol dibenzoate (Benzoflex® 9–88) (C20H22O5) is a primary plasticizer. It has a low order of toxicity, is biodegradable and is rapidly eliminated by mammals. The effect of Benzoflex 9–88 on microbial functions was mixed (cellulose degradation, urea degradation and sulfate reduction). Its octanol-water partition coefficient is 455 ± 15. It was not mutagenic in the Ames test and the Saccharomyces test.
Acute and chronic effects of diflubenzuron (Dimilin) on freshwater fish and invertebrates
Authors: Nebeker Alan V. , McKinney Phillip , Cairns Michael A.
Published: March 2010

Two fish and seven invertebrate freshwater species were exposed to diflubenzuron (Dimilin®) in acute and chronic laboratory tests. No effects on newly hatched and juvenile fathead minnows or juvenile guppies were seen at or below 36 μg/L, the highest concentration tested. An early-life-stage test (30-d) with fathead minnows showed no effect at or below 36 μg/L. No effects on survival, growth or reproduction were observed with two snail species, Juga plicifera and Physa spp., at or below 36 μg/L. Adult emergence of the caddis fly Clistoronia magnifica was inhibited at 0.1 μg/L. Daphnia magna were killed at 2.0 μg/L. Hyalella azteca mortality was significant at 2.0 μg/L. Molting and survival of the midge Tanytarsus dissimilis were affected at 4.9 μg/L. Molting and survival of the midge Cricotopus spp. were affected at 4.9 μg/L, and adult emergence did not occur at 1.6 μg/L.
Ultrastructural changes in the hepatocytes of juvenile rainbow trout and mature brown trout exposed to copper or zinc
Authors: Leland Harry V.
Published: March 2010

Morphological changes in hepatocytes of mature brown trout (Salmo trutta Linnaeus) and juvenile rainbow trout (Salmo gairdneri Richardson), accompanying chronic exposures to copper and zinc, were examined by transmission electron microscopy. At a concentration of copper not inhibitory to the final stages of gonadal development or spawning of brown trout, structural alterations included contraction of mitochondria and a tendency for nuclei to be slightly enlarged. Concentrations of copper or zinc lethal to a small fraction (10% and 4%, respectively) of a population of juvenile rainbow trout exposed for 42 d during larval and early juvenile development caused hepatocyte changes in survivors indicative of a reduction in ability to maintain intracellular water and cation balance and possible intranuclear metal sequestering. Specific structural alterations included increased vesiculation of rough endoplasmic reticulum, an increase in the abundance of electron-dense particles in the nucleus, increases in the numbers of multilaminar and globular inclusions, pooling of glycogen, increased autophagocytic activity and an increase in the number of necrotic cells. At advanced stages of toxicosis (concentrations of copper or zinc lethal to approximately 50% of the juveniles exposed for 42 d during development), loss in integrity of mitochondrial membranes, rupturing of plasma and nuclear membranes, separation of granular and fibrillar nuclear components, fragmentation of endoplasmic reticulum, and extensive autophagic vacuolization were significant features of hepatocytes of surviving juvenile rainbow trout.
The mussel watch: Intercomparison of trace level constituent determinations
Authors: Galloway Walter B. , Lake James L. , Phelps Donald K. , Rogerson Peter F. , Bowen Vaughan T. , Farrington John W. , Goldberg Edward D. , Laseter John L. , Lawler George C. , Martin John H. , Risebrough Robert W.
Published: March 2010

The U.S. National Mussel Watch Program initially used split-sample analyses for interlaboratory quality control purposes. These indicated the possibility of interlaboratory analytical discrepancies as well as problems in the split-sample technique itself. For the third year of the program, two mussel homogenates were produced to serve as intercomparison samples — one for metals and organics, the other for radionuclides. The results obtained using these homogenates are encouraging in that generally good agreement is seen among analyses done by several labs in diverse pollutant classes. We conclude from this experience that a quality-control program relying on the analysis of large homogeneous samples of the matrix being dealt with is an essential part of any extensive, multilaboratory analytical program.
Monitoring aldicarb residues in Florida soil and water
Authors: Jones R. L. , Back R. C.
Published: March 2010

Soil and water monitoring studies have been conducted to characterize the movement of aldicarb residues in Florida citrus groves. Samples were taken in 1980 and 1981 from TEMIK-treated groves on six farms located in five counties. In the soil, aldicarb residues decay rapidly to relatively nontoxic compounds. No significant concentrations of aldicarb were found in potable wells or in surface water around the six sampling sites. The monitoring results have been compared with the predictions of the Environmental Protection Agency computer model PESTAN. These calculations indicate that only a small fraction (< 1%) of the aldicarb applied to a Florida citrus grove during the spring flush (the required application period) would normally reach shallow groundwater. The monitoring data and model calculations demonstrate that the use of TEMIK in Florida citrus groves will not result in persistent aldicarb residues in Florida groundwater.
Evaluation of a static renewal chronic toxicity test method for Daphnia magna straus using boric acid
Authors: Gersich Francis M.
Published: March 2010

A procedure for conducting chronic daphnid static renewal tests has been developed and evaluated, using boric acid as the test material. This procedure is an improvement over other proposed procedures for the following reasons: (a) the test methodology and equipment simplify the operations required to perform the test, (b) data on all endpoints for a particular concentration are obtained from the same group of test organisms and (c) the experimental design permits statistical interpretation of the critical endpoints. The acute and chronic effects of boric acid on Daphnia magna were similar to those reported in the literature. The 48-h static acute LC50 value (and 95% confidence intervals) for boric acid were 133 (115–153) mg/L as boron. The chronic toxicity of boric acid estimated by derivation of the maximum acceptable toxicant concentration was between 6.4 and 13.6 mg/L as boron.
Evaluation of the potential hazard to barn owls of talon (brodifacoum bait) used to control rats and house mice
Authors: Hegdal Paul L. , Blaskiewicz Raymond W.
Published: March 2010

During 1980, a radiotelemetry study on barn owls (Tyto alba) was conducted to evaluate the secondary hazards of the anticoagulant rodenticide TALON® (containing 0.005% brodifacoum) when it was used for controlling rats (Rattus spp.) and house mice (Mus musculus) on farms. Thirty-five active nests were located in about 1,100 km2 (430 mi2) in southwestern New Jersey. Starting on June 9, 1980, radio transmitters with tail clips were attached to 26 adult nesting barn owls and 8 fledged young of the year. In one 20-km2 (about 8 mi2) area, which was the most intensively searched, 12 active barn owl nests were located. Of all 35 active nests, 66% were in trees, 11% in barns, 8.5% in silos, 8.5% in chimneys and 6% in miscellaneous locations. Analysis of regurgitated pellets showed that meadow voles (Microtus pennsylvanicus) were the most common prey at all sites. Although Norway rats (Rattus norvegicus) and house mice occurred in some pellet collections, they made up only a small part of the diet (3.9% rats and 2% mice) of barn owls in the study area. Baiting at farms with TALON was begun on July 24, and ended on September 29, 1980. TALON was not observed to cause or implicated in barn owl mortality during the study. However, trace residues (< 0.05 ppm, the limit of determination) of brodifacoum were found in one electrocuted barn owl. Young barn owls were fledged from at least eight sites where poisoned rodents were available on the farms for at least part of the nesting and feeding period (including pre- and postfledging). Furthermore, radiotelemetry confirmed that at least 9, and possibly 12, of the radio-equipped owls were present on sites posttreatment, when census evaluations showed commensal rodents were present and consuming TALON bait.
Absence of mutagenic activity of sodium borate (borax) and boric acid in the Salmonella preincubation test
Authors: Benson William H. , Birge Wesley J. , Dorough H. Wyman
Published: March 2010

The mutagenicity of borax and boric acid was examined in Salmonella typhimurium strains TA98 and TA100 by the preincubation method. No mutagenic activity of borax or boric acid was observed with or without S-9 rat liver enzymes. Experiments also were conducted to investigate the enhancement or inhibition of benzo[a]pyrene (B[a]P) mutagenicity by the two compounds. Neither Borax nor boric acid had any effect on the response of S. typhimurium test strains to B[a]P. Studies conducted to determine the influence of exposure to sunlight for 8 h on the mutagenicity of these materials showed that the nonmutagenic activity of borax or boric acid was not altered, but that the mutagenicity of B[a]P was reduced by approximately one-half. Photodecomposition may be an important factor in rendering this polycyclic aromatic hydrocarbon nonmutagenic under environmental conditions.
Effects of cadmium on the population growth of a benthic invertebrate Aeolosoma Headleyi (oligochaeta)
Authors: Niederlehner B. R. , Buikema A. L. , Pittinger C. A. , Cairns J.
Published: March 2010

A chronic toxicity test using population growth of an aquatic oligochaete, Aeolosoma headleyi, was evaluated for usefulness in determining the hazard of chronic exposures to cadmium. Tests were conducted in artificial hard water (180 mg/L hardness) and dechlorinated tap water (60 mg/L hardness). After 10 to 14 d of exposure, there were significant differences between groups in population growth rate or number of worms in both water types. The no-observable-effects concentrations (NOEC) for replicate tests in artificial hard water were 32.0 and 53.6 μg/L cadmium. The 48-h LC50 in artificial hard water was 4,980 μg/L, yielding acute/chronic ratios of 155 and 92, respectively. The oligochaete was more sensitive in the softer dechlorinated tap water, with a NOEC of 17.2 μg/L cadmium and a 48-h LC50 of 1,200 μg/L. The acute/chronic ratio was 70. Dose-response curves were linear at higher concentrations, but stimulation of reproduction was noted at low concentrations. A. headleyi was comparable in sensitivity to other organisms tested, as cited by the U.S. Environmental Protection Agency criterion document, in acute exposures but less sensitive in chronic exposures. The test proved to be short and simple, and provided useful data on an animal with a life history distinctly different from that of the most commonly tested aquatic invertebrate, Daphnia.
Toxicity of cadmium in water and sediment slurries to Daphnia Magna
Authors: Nelson Peter O. , Ratcliff Alan K. , Schuytema Gerald S. , Malueg Kenneth W. , Nebeker Alan V. , Krawczyk Daniel F. , Gakstatter Jack H.
Published: March 2010

Daphnia magna Straus were exposed to cadmium for 48 h in water and in equilibrated water-sediment slurries using beakers and recirculating test chambers. Differences in toxicity based on dissolved and free cadmium (Cd2+) between the two levels of tested total solids, 100 and 1000 mg/L, were not significant (α = 0.05). The mean water LC50 of 39 μg/L total cadmium was significantly (α = 0.05) lower than the mean LC50 of 91 μg/L dissolved cadmium in the slurries, indicating that cadmium adsorbed to the sediment had negligible toxicity. Low LC50 values in two sediment bioassays correspond with low pH's. Adsorption isotherms using cadmium, well water, and freshwater sediment were developed for sediment concentrations approximating those at which the bioassays were performed. Conditional adsorption constants derived from the isotherms predicted the distribution of cadmium between well water and sediments. A speciation model predicted that organic ligands released from the sediments strongly complexed the free cadmium ion. Based on free cadmium ion concentrations, no significant differences (α = 0.05) could be detected between the mean of the slurry bioassay LC50 (47 μg/L) and aqueous bioassay LC50 (30 μg/L). Speciation results, LC50 values based on free cadmium ion concentrations only, and pH results gave indirect evidence that the free cadmium ion was the predominant toxic species to D. magna in the bioassays.
Surveillance of phthalate esters in surface waters and sediments in the United States
Authors: Michael Paul R. , Adams William J. , Werner A. Frances , Hicks Orville
Published: March 2010

Four phthalate ester products (three alkyl benzyl and one dialkyl phthalate) were monitored in industrial areas of the United States over 3 years (1980–1982). Documented methodology and quality assurance practices for both sample collection and analysis assured validity of results. The geometric mean concentration (corrected for method losses) for the three benzyl phthalates was less than 0.6 μg/L in surface waters and less than 0.2 μg/g in sediments. Only 20 of 205 water samples (10%) and 13 of 122 sediment samples (11%) had detectable levels of one of the benzyl phthalates. The geometric mean concentration (corrected for method losses) for C7,9,11 dialkyl phthalate was less than 3 μg/L in surface waters and less than 0.6 μg/g in sediments. Only 13 of 138 water samples (9%) and 1 of 90 sediment samples (1%) had detectable levels of C7,9,11 dialkyl phthalate.
Effects of chronic exposure to coal-derived oil on freshwater ecosystems: II. Experimental ponds
Authors: Giddings Jeffrey M. , Franco Paul J. , Cushman Robert M. , Hook Leslie A. , Southworth George R. , Stewart Arthur J.
Published: March 2010

Ten 15-m3 outdoor ponds were treated daily for 8 weeks with a synthetic coal-derived crude oil; ecological effects were monitored for an additional 52 weeks. The experimental design included two replicate ponds at each of five oil input rates (from 1 to 16 ml/m3/d) plus two untreated controls. A gradient of responses was observed across the gradient of treatment levels. Cladoceran zooplankton populations and ecosystem metabolism (production/respiration) were affected at the lowest input rate, but the effects disappeared before the end of the oiling period and this exposure level (approximately 3% of the 48-h LC50 for Daphnia magna) was considered safe for this ecosystem. At the next higher treatment level, effects on zooplankton and ecosystem metabolism were greater and persisted until the oiling ended; reproduction of mosquitofish (Gambusia affmis) was also impaired. Major changes occurred throughout the ecosystem at higher treatment levels. The two highest treatment levels completely disrupted the pond community: The ponds recovered from the next-to-highest treatment but the effects of the highest treatment persisted for more than a year. Indirect effects occurred at all treatment levels and included changes in water quality, replacement of sensitive taxa by more tolerant competitors and changes in abundance of some species because of increases or decreases in their predators. The results of this experiment were qualitatively and quantitatively similar to those of a parallel experiment in pond-derived microcosms, and thus substantiated the ability of the microcosms to simulate larger, more natural ecosystems.
Subchronic mercury exposure in coturnix and a method of hazard evaluation
Authors: Hill Elwood F. , Soares Joseph H.
Published: March 2010

The sublethal toxicity of inorganic (HgCl2) and organic (CH3HgCl) mercury chloride was studied in coturnix (Coturnix japonica) by feeding them mercuric compounds (CH3HgCl at concentrations of 0.125,0.5,2 and 8 ppm; HgCl2 at 0.5, 2, 8 and 32 ppm) in ad libitum diets from hatching to adulthood. Differences of response to the mercurials were compared on the basis of selected indicator enzymes and plasma chemistries. Comparisons of response to equivalent concentrations of the two mercurials and dose-response relationships were made at 1,3,5,7 and 9 weeks. Changes of activity were detected for brain acetylcholinesterase (AChE) and the plasma enzymes aspartate aminotransferase (ASAT), butyrylcholinesterase (BChE), lactate dehydrogenase (LDH) and ornithine carbamoyl transferase (OCT). Changes of ASAT, LDH and OCT were then quantified by probit analysis and the mercurials were compared through their median effective concentrations (EC50). This quantal procedure was based on the establishment of normal control values for each enzyme and then classifying mercury-treated outliers (more than ± 2 SD) as respondents. The EC50 values at 9 weeks for ASAT, LDH and OCT, respectively, were 9, 3 and 63 ppm for HgCl2, and 5, 1 and 4 ppm for CH3HgCl. These results provided the basis for two hazard indices that were calculated by dividing the EC50 into the oral LD50 and the 5-d dietary LC50. Mercury also had contradictory effects on gonadal maturation in both sexes.
Inhibitory interactions of aromatic organics during microbial degradation
Authors: Meyer Joseph S. , Marcus Michael D. , Bergman Harold L.
Published: March 2010

Phenol, benzene and naphthalene were exposed, both singly and in combination, to oil refinery settling pond inocula. Although all three aromatic organics degraded rapidly when dosed singly, benzene and naphthalene were not metabolized in the presence of phenol. These results illustrate the difficulty of predicting environmental fates of complex chemical mixtures.
Placental and mammary transfer of a polychlorinated biphenyl mixture (aroclor 1254) in the European Ferret (Mustela putorius furo)
Authors: Bleavins Michael R. , Breslin William J. , Aulerich Richard J. , Ringer Robert K.
Published: March 2010

Adult female ferrets were found to absorb 85.4% of a single dietary dose of the polychlorinated biphenyl (PCB) mixture Aroclor 1254. Excretion in the days immediately following dosing yielded the greatest quantity of PCBs eliminated in a given time period. In general, urinary excretion represented one-tenth or less of the PCBs excreted via the feces. Placental transfer to the ferret kits was 0.01% (per kit) of the female's absorbed dose when exposure occurred during the first trimester of pregnancy and 0.04% (per kit) when the PCBs were administered during the third trimester. Transplacental exposure to PCBs was considerably less than that reaching the kits through the dam's milk. The ratio of placental to mammary transfer, following 1 week of lactation, was calculated to be approximately 1:15 for the offspring of first-trimester-dosed females and 1:7 for the offspring produced by females treated during the third trimester.
Estimation of bioconcentration in marine species using structure-activity models
Authors: Zaroogian G. E. , Johnson M. , Heltshe J. F.
Published: March 2010

Structure-activity models, which were developed to predict bioconcentration of organic chemicals in freshwater fish, were tested for use with several marine species (Cyprinodon variegatus, Lagodon rhomboides, Crassostrea virginica, Mytilus edulis). Significant linear relationships existed between the bioconcentration factor (BCF) for each marine species tested and the log of the octanol/water partition coefficient (P). The results suggest that freshwater models can be used to predict the BCF of a chemical in marine species, since the slopes of the freshwater models were within the 95% confidence intervals for marine models. Models derived from data on freshwater species were used to calculate BCF values for each of the marine species. The calculated BCF values were compared with the measured BCF values for each marine species and those measured for the fathead minnow (Pimephales promelas). The data indicate that the log BCF can be estimated for the marine species using freshwater models to within one order of magnitude for a minimum of 71% of the chemicals having a range of 3,000,000 in the partition coefficient (1.61 to 6.50 in log P). It appears that models based on data from freshwater species offer the same precision in estimation of BCF values for marine species as for freshwater fish. Good agreement existed between measured and calculated BCF values for both L. rhomboides and M. edulis, whereas the data for C. virginica were more variable and those for C. variegatus were the most variable. Tests indicated that, generally, calculated BCF values overestimate the measured BCF values. Significant linear relationships existed between measured BCF values for P. promelas and each marine species, except M. edulis.
Comparative toxicity of copper and acridine to fish, Daphnia and algae
Authors: Blaylock B. G. , Frank M. L. , McCarthy J. F.
Published: March 2010

A comparison was made of the sensitivity of fish, Daphnia and algae to the toxic effects of copper and acridine. A series of toxicity tests was conducted with these organisms, and the following biological endpoints determined: LC50s for fish, LC50s and effects on reproduction of Daphnia and 50% inhibition of the growth rate of algae. The 96-h LC50s for bluegill (Lepomis macrochirus) and Daphnia magna exposed to copper were 2.2 and 0.13 mg/L, respectively. A chronic exposure to 0.03 mg/L of copper for 14 d significantly decreased reproduction in Daphnia. Exposure to 0.4 and 0.2 mg/L copper inhibited the growth rate of Selenastrum capricornutum and Chlorella vulgaris, respectively, by 50%. The 96-h LC50s for fathead minnows (Pimephales promelas) and D. magna exposed to acridine were 2.3 and 3.1 mg/L, respectively. A chronic exposure to 1.25 mg/L acridine for 14 d significantly inhibited reproduction in Daphnia, and an exposure to 0.9 mg/L inhibited the growth rate of S. capricornutum by 50%. Based on the biological endpoints determined in these tests, Daphnia were more sensitive to copper than were fish or algae. In contrast, the most sensitive biological endpoint in tests with acridine was the inhibition of algal growth. Comparison of these test results indicates that short-term toxicity tests used for screening toxicants for possible environmental effects should include both plant and animal species.
The use of quantitative structure-activity relationships to predict the acute and chronic toxicities of organic chemicals to fish
Authors: McCarty L. S. , Hodson P. V. , Craig G. R. , Kaiser K. L. E.
Published: March 2010

Quantitative structure-activity relationships (QSARs) predict bioconcentration and acute toxicity to fish of chemicals causing narcosis on the basis of hydrophobicity, as measured by the octanol/water partition coefficient (Kow). Since the development of water quality objectives to protect fish is limited by the availability of suitable chronic toxicity data, we applied the QSAR concept to published and unpublished data to determine (a) whether chronic toxicity could be related to Kow and (b) whether application factors are constant, i.e., whether QSARs for acute and chronic toxicity are parallel. Our conclusions are as follows: (1) A QSAR, based on hydrophobicity (log Kow), appears to exist for the chronic toxicity of organic chemicals inducing acute toxicity by narcosis. Although not definitive, this QSAR was not parallel to that for acute toxicity and does not appear to support the concept of constant application factors. (2) Log Kow has a major effect on the rate of net bioconcentration of certain organic chemicals; therefore, the relationship of toxicity to log Kow may not be linear if exposure times are fixed, as very different amounts of toxicants will be taken up over a fixed time period. (3) As a result of the effect of log Kow on bioconcentration rates, many toxicity tests of relatively short, fixed duration may underestimate toxicity of some hydrophobic organic compounds, especially those exhibiting high log Kow values. Hence, water quality objectives developed directly from this data, without appropriate compensation, may not be restrictive enough. (4) To increase the accuracy, comparability and applicability of aquatic bioassay test results, especially for compounds of widely differing hydrophobicity, standard tests should be redesigned. For example, it may be more accurate if the exposure or dosage for the test organism is expressed as a summation of the periodically calculated product of body toxicant level and time up to predetermined summation values.
Reevaluation of volatile nitrosamines in human feces
Authors: Suzuki Kunio , Mitsuoka Tomotari
Published: March 2010

The artifactual generation of N-nitrosamines during analytical procedures and the presence of volatile nitrosamines in human feces were reinvestigated. Various solvents and desiccants — sodium sulfate, magnesium sulfate and calcium chloride—were highly catalytic in nature and induced marked N-nitrosation of secondary amines. During the N-nitrosamine analysis, high levels of volatile nitrosamines, detected in the original method using dichloromethane as the extracting solvent and sodium sulfate as the desiccant, were artifactually generated. Few volatile nitrosamines were detected by the new method, in which extraction by ether and dehydration by potassium carbonate were carried out. The recovery values of volatile nitrosamines by the new method were similar to the values obtained by the original method. Therefore, it is concluded that volatile nitrosamines do not seem likely to be present in significant amounts in human feces.
Characterizing the aerobic and anaerobic microbial activities in surface and subsurface soils
Authors: Ward Thomas E.
Published: March 2010

Studies were conducted to characterize the aerobic and anaerobic microbial activities in surface and subsurface soils of septic tank tile fields. Under aerobic conditions, the indigenous microflora in the soils degraded the natural substrates and many of the synthetic chemicals tested. Half-lives (t1/2) for the biodegradation (14CO2 production) of glucose and glutamic acid ranged from 2 to 5 h in surface soils and from 8 to 25 h in subsurface soils. Degradation of stearic acid was slower in both surface (t1/2 = 118 h) and subsurface (t1/2 = 82 to 312 h) soils. 14CO2 evolution from the synthetic chemicals methyl parathion and 2,4-D was more variable than that from the natural substrates and occurred in the surface soil but in only one of the two subsurface soils tested. The aerobic biodegradation of nitrilotriacetate (NTA) was studied only in the two subsurface soils from the tile fields. NTA was mineralized in both soils and the half-life for 14CO2 production ranged from 86 to 161 h. When the surface and subsurface soils were incubated under anaerobic (nitrate-reducing) conditions, active denitrification by the indigenous microflora was observed. In surface soils, denitrification occurred immediately after an anaerobic preincubation (12 to 24 h) and the N2O production curve was linear. In subsurface soils, N2O production occurred only after 32 to 44 h of anaerobic incubation and was described by an S-shaped curve. Biodegradation of the natural substrates (glucose, glutamic and acetic acid) under these anaerobic conditions ranged from 1 to 2 h for the surface soil to 2 to 20 h for subsurface soils. The half-life for the anaerobic mineralization of NTA ranged from 49 to 125 h in the subsurface soils. The results indicate that the indigenous microflora in the subsurface have lower activities than do those in surface soils; however, the subsurface microflora can effectively mineralize natural and certain synthetic substrates under aerobic and denitrifying conditions.
A metabolic derivation of DDE from kelthane®
Authors: Risebrough Robert W. , Jarman Walter M. , Springer Alan M. , Walker Wayman , Hunt W. Grainger
Published: March 2010

DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene), the DDT derivative that causes thinning of the eggshells of sensitive bird species, is metabolically formed in mallard ducks fed Kelthane®, a widely used acaricide that consists of technical dicofol, a mixture of compounds synthetically derived from technical DDT. Technical dicofol mixtures contain very low levels of p,p'-DDT, which has been assumed to be the only precursor to environmental DDE. Applications of Kelthane and of other products containing technical dicofol would therefore increase the environmental input of DDE, accounting at least in part for recent observations of high levels of DDE in environmental samples from Texas, New Mexico, Arizona and California that contained only trace amounts of DDT. Among the components of Kelthane, chloro-DDT (1,1,1,2-tetrachloro-2,2-bis(p-chlorophenyl)ethane) is converted to DDE under certain laboratory conditions. Levels of chloro-DDT in the Kelthane mixture employed could account for all of the DDE metabolically formed in the ducks. The data leave unresolved the question of whether DDE may be derived from p,p'-dicofol (1,1-bis(p-chlorophenyl)-2,2,2-trichloroethanol), the principal ingredient of technical dicofol, under either experimental or environmental conditions.
Biological half-lives of chlorinated dibenzo-p-dioxins and dibenzofurans in rainbow trout (Salmo gairdneri)
Authors: Niimi A. J. , Oliver B. G.
Published: March 2010

The biological half-lives of five dibenzo-p-dioxins and two dibenzofurans were determined in rainbow trout following a single oral exposure. Estimated half-lives ranged from 2 d for 2,7-dichlorodibenzo-p-dioxin to 43 d for 1,2,3,4-tetrachlorodibenzo-p-dioxin among the dioxins, and from 12 d for octachlorodibenzofuran to 24 d for 3,6-dichlorodibenzofuran. No consistent relationship was shown between half-life and the degree of chlorination. Absorption efficiencies varied from 2 to greater than 30%, although most values ranged from 5 to 16%.
Arthropods associated with pesticide leach lines in selected orchards in central New York
Authors: Baker P. B. , Hoebeke E. R. , Barnard J. , Spittler T. D.
Published: March 2010

Chemical control centers were constructed on selected farms in Wayne County, New York, to minimize pesticide pollutants. These centers provided areas where several classes of agricultural chemicals, primarily those from spray operations, could be handled and disposed of safely. We surveyed the arthropod fauna found above the pesticide leach lines and in adjacent soils. Of the 70 arthropod taxa determined, we identified the following families: Diptera (18 families), Hymemoptera (12), Coleoptera (7), Hemiptera (3), Homoptera (1) and Thysanoptera (1). Seasonal comparisons of arthropods above the pesticide leach lines and in the checks showed no apparent differences. Slight taxa variations were observed within and between farms with chemical control centers. No residues greater than 0.2 ppm were found in either water or soil samples. These results imply that no contamination of the environment was caused by the use of the chemical control centers.
Conditional stability constants and binding capacities for copper (II) by dissolved organic carbon isolated from surface waters of the southeastern United States
Authors: Giesy John P. , Alberts James J. , Evans David W.
Published: March 2010

Dissolved organic carbon (DOC), isolated from each of nine surface waters in the southeastern United States, was fractionated into two nominal molecular size fractions, i.e., 52 Å < fraction I < 4,500 Å and 13 Å < fraction II < 52 Å. The binding capacities and overall conditional stability constants (K̄') for copper were determined by selective ion electrode. The binding capacities ranged from 2.4 × 10−7 to 1.3 × 10−5 M Cu/mg DOC, with a mean for all locations and fractions of 2.2 × 10−6 (SD = 6.2 × 10−5, n = 15). There was no significant difference (Mann-Whitney U Test, p > 0.2) between binding capacities of fractions I and II. Sensitivity analyses showed that the overall mean binding capacity was adequate for use in simulation models. We estimated overall conditional stability constants by seven mathematical techniques, including both discrete and continuous models. The thermodynamic, geochemical simulation model GEOCHEM was used to determine the sensitivity of predictions to variation in both binding capacity and overall conditional stability constants estimated by each technique. Predictions were compared with titrations of isolated humate fractions and whole waters. The two-component Scatchard function, a discrete model, and the Gaussian-Scatchard function, a continuous model, gave the most accurate predictions in these simulations. We endorse the use of the Gaussian-Scatchard function because it is flexible and has a stronger theoretical basis. Stability constants (K') were calculated for measured values of free and bound metal and ligand across a metal-organic ligand titration curve. These values were dependent on the copper/total ligand ratio and varied on a continuum of binding strength by as much as a factor of 100 for a given fraction and location. The means of maximum conditional stability constants calculated across locations were 5.2 × 105 (SD = 3.9 × 105, n = 7) and 5.9 × 104 (SD = 4.05 × 104, n = 7) for fractions I and II, respectively. The median, maximum conditional stability constant for fraction II was significantly weaker (Mann-Whitney U Test, p < 0.005) than that for fraction I. The number of sites with each K' were log10-normally distributed, with proportionately more of the weaker binding sites.
Comparisons of single-species, microcosm and experimental pond responses to atrazine exposure
Authors: Larsen David P. , Stay Frank , Shiroyama Tamotsu , Frank DeNoyelles
Published: March 2010

Results from single-species toxicity tests form the basis for guidance about concentrations of chemicals that are likely to be environmentally hazardous. Microcosm bioassays have been proposed as better tools for this purpose under some circumstances. Rarely have comparisons been made among the responses in the various test systems and those seen in natural communities. We compared the responses among single-species algal assays, a synthetic microcosm (the Taub microcosm) and experimental ponds exposed to similar concentrations of atrazine by comparing concentrations of atrazine that reduced algal activity or biomass to 50% of control values (EC50). Eight algal species were examined; mean species EC50 values for 14C uptake ranged from 37 to 308 μg/L. For the Taub microcosm, EC50 values were 103 to 159 μg/L for 14C uptake, 126 to 165 μg/L for dissolved oxygen production and 106 to 164 μg/L for dissolved oxygen consumption. Values were dependent on the time intervals selected for calculations. In the ponds, EC50 values for 14C uptake were 100 μg/L and for chlorophyll a, 82 μg/L. The basic similarity among EC50 values across test systems suggests that results from a combination of single-species assays, or the Taub microcosm, provided a reasonable estimate of the concentration of atrazine that produced similar direct effects on more natural communities.
Development of environmental scenarios for modeling the fate of agricultural chemicals in soil
Authors: Oliver George R. , Laskowski Dennis A.
Published: March 2010

Modeling has become a popular preliminary screening and predictive tool for assessing the environmental fate of agricultural chemicals. For modeling to be effective, realistic soil and climatic background inputs must be used. A procedure to quickly develop these environmental scenarios from readily available data sources for modeling leaching and dissipation is discussed, using the herbicide tridiphane as an example. Computerized soil survey information was used to identify soils most likely to be encountered in major use areas. A climatic model generated rainfall patterns for the study areas and provided the probability statement for the environmental assessment. Less than 5 man-days of effort were required for the formulation of four realistic scenarios to use in the evaluation of the leaching and dissipation of tridiphane in key future markets.
Cholinesterase inhibition in meadow voles (Microtus Pennsylvanicus) following field applications of orthene®
Authors: Jett David A.
Published: March 2010

Brain acetylcholinesterase activity in field-caught meadow voles (Microtus pennsylvanicus) was depressed after a field-spray of Orthene® (acephate: acetylphosphoramidothioic acid O,S-dimethyl ester) by as much as 32% in 1982 and 38% in 1983. Short-term recovery was demonstrated and occurred in a time-dependent fashion in 1982. Plasma Cholinesterase levels were more variable but also were depressed. Residues were detected in vegetation samples and in the gastrointestinal tracts of exposed voles. Residues in vegetation were diluted or absent 7 to 8 d following the treatment.
Bioconcentration and disposition of 1,3,6,8-tetrachlorodibenzo-p-dioxin and octachlorodibenzo-p-dioxin by rainbow trout and fathead minnows
Authors: Muir D.C.G. , Yarechewski A.L. , Knoll A. , Webster G.R.B.
Published: March 2010

Accumulation of 14C-labeled 1,3,6,8-tetrachlorodibenzo-p-dioxin (TCDD) and octachlorodibenzo-p-dioxin (OCDD) from water by rainbow trout fry (Salmo gairdneri) and fathead minnows (Pimephales promelas) was studied using a 5-d uptake and 24 to 48-d depuration period. Average exposure concentrations ranged from 4 to 211 ng/L for 1,3,6,8-TCDD and from 9 to 415 ng/L for OCDD. Equilibrium bioconcentration factors for total 14C in fish, calculated by use of a two-compartment first-order rate model, were 2,100 and 5,702 for 1,3,6,8-TCDD in trout fry and minnows, respectively, and 85 and 2,226 for OCDD in the same species. Elimination rates of both isomers were rapid, with half-lives of 14C ranging from 6 to 9 d for 1,3,6,8-TCDD and from 5 to 13 d for OCDD. The highest concentrations of radiolabeled 1,3,6,8-TCDD and OCDD were found in bile. A metabolite of 1,3,6,8-TCDD in bile was identified as a conjugate of a hydroxylated tetrachloro-derivative. Dietary exposure of rainbow trout resulted in low accumulation factors, ranging from 0.034 for OCDD to 0.018 for 1,3,6,8-TCDD, based on toluene-extractable radioactivity.
Effect of pulse exposure to methoxychlor on brain serotonin levels in american flagfish (Jordanella Floridae, goode and bean) as modified by time after exposure, concentration and gender
Authors: Holdway D.A. , Sloley B.D. , Downer R.G.H. , Dixon D.G.
Published: March 2010

Adult American flagfish (Jordanella floridae) were exposed for 2 h to 1.6, 1.9, 3.1 or 5.1 mg L−1 of the chlorinated hydrocarbon insecticide methoxychlor. Control and ethanol-carrier control treatments were also maintained. Fish were sampled at 2, 6, 24, 48 and 336 h after exposure, and the concentrations of tryptophan, serotonin and 5-hydroxyindole acetic acid in brain tissue were determined. Flagfish exposed to the three highest concentrations of methoxychlor had significantly lower concentrations of serotonin, relative to controls, 2, 6 and 24 h after exposure. Serotonin concentrations had returned to control levels by 48 h. The period of serotonin depression corresponded with observed convulsive activity in the exposed fish. Female flagfish had significantly higher brain levels of serotonin than did males. Although tryptophan and 5-hydroxyindole acetic acid levels were unaffected by methoxychlor exposure, the levels of both were significantly depressed by the concentration of ethanol carrier (270 mg L−1) used. Serotonin levels were unaffected by ethanol. The brain weight of flagfish was found to be related to body weight by the equation brain weight (mg) = 2.53 + 5.72 body weight (g) (n = 139; r2 = 0.74; p < 0.001).
Comparison of the effects of surfactants on freshwater phytoplankton communities in experimental enclosures and on algal population growth in the laboratory
Authors: Lewis Michael A.
Published: March 2010

Field validation of laboratory toxicity data for phytoplankton is uncommon but it is important, since results from standard single-species laboratory tests are often used in assessing the environmental safety of a chemical. This study reports the short-term in situ effects of three surfactants on the community structure of enclosed natural assemblages of phytoplankton. Standard diversity and similarity indices, mean species number and density and changes in dissolved oxygen concentration were determined for phytoplankton enclosed in 26-liter bottles after 10 d of exposure in Acton Lake, Ohio. The first observed effect concentrations based on commonly calculated indices of community structure occurred at 108, 8.4 and 2.9 mg/1, respectively, for the anionic, nonionic and cationic surfactants. In contrast, lower effect levels (<1.0 mg/1) based on changes in density of some major taxa were observed. Since standard algal toxicity tests assume a degree of environmental relevancy, the community effect levels were compared with effect concentrations developed in standard laboratory algal toxicity tests monitoring changes in population growth of single test species. The community effect levels could be predicted in some cases; however, the degree of similarity between the laboratory and field results was very dependent on the surfactant, the laboratory test species and the effect parameter.