bluuebunny/crossref_metadata_2025 huggingface dataset:
Site-specific toxicity of un-ionized ammonia in the tittabawassee river at midland, michigan: Overview
Authors: Alexander Howard C. , Latvaitis P. Brad , Hopkins Daniel L.
Published: March 2010

Site-specific acute and chronic toxicity tests with un-ionized ammonia were conducted in Tittabawassee River water from Midland, Michigan. The results of these tests were used by the State of Michigan Department of Natural Resources (MDNR) to establish site-specific acute and chronic un-ionized ammonia water quality criteria for the portion of the river at Midland. The acute water-quality criterion established by the state using walleye data from this study was 1.0 mg/L un-ionized ammonia nitrogen. The chronic criterion established using fathead minnow embryo-larval data was 0.095 mg/L un-ionized ammonia nitrogen. The chronic criterion was used in determining the assimilative capacity for ammonia in this portion of the river. The MDNR allocated a portion of the assimilative capacity to each discharger and set effluent limitations based on the allocated capacities. Ammonia effluent limits have been set in the National Pollutant Discharge Elimination System (NPDES) permits of the Dow Chemical Company and the City of Midland. Ammonia effluent limits will be set in the NPDES permit of the Consumers Power Company.
Site-specific acute and chronic toxicity of ammonia to Daphnia magna straus
Authors: Gersich F. M. , Hopkins D. L.
Published: March 2010

The acute and chronic toxicity of ammonia (expressed as un-ionized ammonia nitrogen, NH3-N) to Daphnia magna was determined in support of the development of site-specific water quality standards for ammonia in the Tittabawassee River at Midland, Michigan. The 48-h LC50 value (95% confidence interval) obtained was 2.94 (2.70 to 3.22) mg NH3-N/L. The 21-d chronic value, presented as the maximum acceptable toxicant concentration (MATC), was between 0.42 and 0.87 mg NH3-N/L. Expressing the chronic value as the geometric mean of 0.42 and 0.87 resulted in an MATC of 0.60 mg NH3-N/L. The toxicity values derived during this study were similar to those reported in the literature for D. magna.
Biodegradation of pyridine derivatives in soil suspensions
Authors: Sims Gerald K. , Sommers Lee E.
Published: March 2010

Relationships between structure and biodegradability were evaluated for 28 pyridine derivatives in nutrient solutions inoculated with soil and incubated at 24°C. Compounds studied included pyridine; mono- and disubstituted pyridinecarboxylic acids; and hydroxy-, chloro-, amino-and methylpyridines. Disappearance of the pyridine added was measured by UV spectrophotometry, and the ammonium released by cleavage of the pyridine ring was measured by colorimetry. Volatilization was estimated by analysis of the pyridines collected on the polyurethane foam stoppers used to plug the incubation vessels; sorption by soil was estimated from the initial decrease in solution concentration upon addition of soil. Pyridinecarboxylic acids, monohydroxypyridines and the unsubstituted pyridine ring did not volatilize and were degraded within 7 to 24 d. Methylpyridines were intermediate in degradability, disappearing in from less than 7 to more than 30 d. None of the aminopyridines was completely degraded in 30 d. Of the chloropyridines tested, only 4-chloropyridine was completely degraded in 24 d. The susceptibility of 4-chloropyridine to degradation may be attributed to the ease with which a chlorine group is removed from position 4 on the pyridine ring. No degradation was detected in 30 d for any of the other chloropyridines. Chloro-and methylpyridines volatilized extensively.
Effect of age on sensitivity ofDaphnia Magnato cadmium, copper and cyanazine
Authors: Nebeker Alan V. , Cairns Michael A. , Onjukka Samuel T. , Titus Ray H.
Published: March 2010

Daphnia magna were exposed to cadmium, copper and cyanazine to determine the relative sensitivities of several age groups: less than 4 h, less than 24 h, 1 d, 2 d, 3 d, 4 d, 5 d and 6 d old. Mean cadmium 48-h EC50 values for each age group ranged from 23 to 164 μg/L. Mean copper EC50 values ranged from 6 to 18 μg/L. Cyanazine EC50 values ranged from 53 to 106 mg/L. The 1-d-old and 5-d-old Daphnia mean EC50s were 48 and 49 μg/L for cadmium, 10 and 10 μg/L for copper and 84 and 86 μg/L for cyanazine, respectively. These similar sensitivities indicate that older animals can be used in tests equally as well as younger animals, thus simplifying the recovery of daphnids in acute sediment toxicity tests.
Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions
Authors: Hedtke Steven F. , West Corlis W. , Allen Kathleen N. , Norberg-King Teresa J. , Mount Donald I.
Published: March 2010

The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were conducted, with LC50 values ranging from 85 μg/L for the white sucker Catastomus commersoni during the summer to greater than 7,770 μg/L for the isopod Asellus racovitzai during the winter. The effect of PCP on growth and/or reproduction was determined for seven species. The most sensitive chronically exposed organisms were the cladoceran Ceriodaphnia reticulata and the snail Physa gyrina. Both were adversely affected at the lowest concentrations tested, i.e., 4.1 and 26 μg/L, respectively. The duckweed Lemna minor was the least sensitive, with no apparent effects after exposure for 21 d to concentrations as high as 1,440 μg/L.

The greatest variation in toxicity was due to species sensitivity. Within a given season there was as much as a 40-fold difference in LC50 values between species. For any one species, the maximum variation in LC50 between seasons was approximately 14-fold. There were also substantial differences in acute-chronic relationships, with acute/chronic ratios ranging from greater than 37 for C. reticulata to 1 for Simocephalus vetulus. It is suggested that the composition of the aquatic community should be the most important consideration in estimating the potential environmental effects of PCP.
Lugworm (Arenicola cristata) larvae in toxicity tests: Survival and development when exposed to organotins
Authors: Walsh Gerald E. , Louie Michael K. , McLaughlin Leslie L. , Lores Emile M.
Published: March 2010

A test is described for the exposure of the lugworm Arenicola cristata to toxicants. Embryos of A. cristata were exposed for 96 and 168 h to bis(triphenyltin) oxide (TPTO), triphenyltin chloride (TPTC), bis(tri-n-butyltin) oxide (TBTO) and tributyltin acetate (TBTA). The toxic effects were death and abnormal development of larvae. Concentrations that killed all animals were 4 μg L−1 (96 h) and 2 μg L−1 (168 h) TPTO; 10 μg L−1 (96 h) and 5 μg L−1 (168 h) TPTC; 4μg L−1 (96 h) TBTO; and 10 μg L−1 (96 h) and 5 μg L−1 (168 h) TBTA. Abnormal morphology was caused by 0.75 μg L−1 TPTO, 1 μg L−1 TPTC and 5 μg L−1 TBTA. Several developmental stages, from embryo to swimming larva, were exposed to TPTO. The most sensitive stages were early trochophore and early settled stage. The range of concentrations between 100% survival and 100% mortality was narrow in all tests. The exposure system is simple and detects teratogenicity.
Photoinduced toxicity of anthracene to juvenile bluegill sunfish (Lepomis Macrochirus Rafinesque): Photoperiod effects and predictive hazard evaluation
Authors: Oris James T. , Giesy John P.
Published: March 2010

The effect of daily light-cycle duration (photoperiod) on the solar ultraviolet radiation (SUVR) -induced toxicity of anthracene to juvenile bluegill sunfish (Lepomis macrochirus R.) in a laboratory system under simulated sunlight was examined. Rates of acute mortality were dependent on both anthracene concentration and photoperiod. Median lethal time values calculated on the basis of accumulated SUVR exposure time (UV-LT50) were compared with LT50 values calculated from real time of exposure (R-LT50) to determine relative rates of phototoxic damage versus physiologic repair during periods of darkness. The comparison of these LT50 values indicated that the photoinduced toxicity of anthracene to fish was slowly repaired during periods of darkness but that enough damage accumulated over several SUVR cycles to cause acute mortality.

The results from these experiments were incorporated into a relationship to predict no-effect anthracene concentrations from the daily light-cycle duration at one SUVR intensity. Information from acute toxicity tests was used to extrapolate to chronic no-effect values. No-effect anthracene concentrations in water were predicted to range from 1.2 μg/L for 24 h light:0 h dark photoperiod to 13.5 μg/L for a 6 h light: 18 h dark photoperiod. A no-effect anthracene body burden of 131 μg/kg has been calculated for juvenile bluegill sunfish for a 16 h light:8 h dark photoperiod at an equivalent depth of 3.0 m in a typical eutrophic system. Thus, considering current natural polycyclic aromatic hydrocarbon concentrations in water and in fish tissue, there exists natural waters in which photoinduced PAH toxicity may occur.
Toxicity of used drilling fluids to mysids (Mysidopsis Bahia)
Authors: Gaetz Charles T. , Montgomery Richard , Duke Thomas W.
Published: March 2010

Static, acute toxicity tests were conducted with mysids (Mysidopsis bahia) and 11 used drilling fluids (also called drilling muds) obtained from active drilling platforms in the Gulf of Mexico in U.S. waters. Each whole mud was tested, along with three phases of each mud: a liquid phase with particulate materials removed, a suspended particulate phase composed of soluble and lighter particulate fractions and a solid phase composed mainly of drill cuttings and rapidly settling particulates. These muds represented seven of the eight generic mud types described by the U.S. Environmental Protection Agency for use on the U.S. outer continental shelf.

Based on volume: volume preparations of the drilling muds in seawater, the lowest 96-h LC50s obtained were 26 μl/L for whole mud, 11,400 μl/L for the liquid phase, 726 μl/L for the suspended particulate phase and 1,456 μg/L for the solid phase. The toxicity of the 11 muds tested was apparently increased by the presence of aliphatic components.
Aqueous photolysis of triclopyr and its butoxyethyl ester and calculated environmental photodecomposition rates
Authors: Mccall P. J. , Gavit P. D.
Published: March 2010

Studies determining the photochemical quantum yields of [(3,5,6-trichloro-2-pyridinyl) oxy]acetic acid (triclopyr) and its butoxyethyl ester are reported. Values of 0.040 ± 0.003 and 0.0084 ± 0.0008, respectively, were obtained using 313-nm light at pH 5 in a dilute aqueous solution at 35°C. Quantum yields were used to compute half-lives for direct photolysis under seasonal and locational sunlight conditions with the computer program SOLAR. Triclopyr was observed to photodegrade approximately six times faster than the ester, with typical calculated midday, midsummer half-lives of 2.1 and 12.5 h, respectively, at the water's surface at 40°C latitude. The relative importance of photolysis to other environmental transport and transformation mechanisms of the chemicals is discussed.
Chemical speciation and bioavailability of copper: Uptake and accumulation by eichornia
Authors: Nor Yahya M. , Cheng H. H.
Published: March 2010

The uptake of copper by water hyacinth (Eichornia crassipes) was studied using solution culture techniques in the greenhouse. The bioassays indicated that the uptake of copper was a direct function of its speciation. For example, only free Cu2+ was absorbed by the plant in the presence of strong ligands such as EDTA and humic acid. Other ligands tested (fulvic acid, amino acids and simple organic acids), however, failed to suppress the uptake of copper even when the free Cu2+ in solution initially was negligibly small. Copper could have been taken up directly by the plant as various complexes or in the free Cu2+ form after dissociation from the ligands prior to uptake. Complete inhibition of copper uptake in the presence of humic acid, in contrast to fulvic acid, suggests that the chemical stability constants of these complexes with copper were not correlated to the metal's bioavailability. The potential of Eichornia for removing heavy metals from wastewaters is demonstrated by its tremendous capacity to bioaccumulate copper. Depending on the presence or absence of ligands, from 200 to more than 2,400 μg Cu g−1 dry matter could be taken up by the plant.
Sorption of low-polarity organic compounds on oxide minerals and aquifer material
Authors: Stauffer Thomas B. , Macintyre William G.
Published: March 2010

Sorption plays a significant role in the transport of low-polarity organic compounds by ground water. Most contaminant movement is through saturated aquifers of low organic carbon content. Sorption processes on these materials may be different from those on high-organic surface soils. Batch sorption isotherms using 14C-labeled compounds were determined on mineral oxides and aquifer materials; the sorbents used were Al2O3, Al(OH)3, FeO(OH) (goethite) and aquifer material. A surface soil sorbate was used for comparison with the sorption of the low-carbon materials; the sorbates used were 1-methylnaphthalene, naphthalene, trichloroethylene and o-dichlorobenzene. The acidity and ionic strength were varied to simulate different ground water conditions. The order of sorption coefficients for all sorbents was 1-methylnaphthalene > naphthalene > o-dichlorobenzene > trichloroethylene. In general, sorption of each compound was strongest for the surface soil and decreased in the order of surface soil >> FeO(OH) > aquifer material > aluminum oxides. Under basic conditions, the sorption coefficients were significantly reduced in all cases. Sorption increased slightly at high ionic strengths.
Development and validation of site-specific water quality criteria for copper
Authors: Carlson Anthony R. , Nelson Henry , Hammermeister Dean
Published: March 2010

Comparative acute toxicity values for Ceriodaphnia dubia, Scapholeberis sp. and Pimephales promelas exposed to copper were used to calculate water effect ratios (e.g., site water LC50 value/reference water LC50 value), which reflect the difference in the biological availability and/or toxicity of copper between water from the Naugatuck River, Connecticut and Lake Superior reference water. These ratios were used to modify U.S. Environmental Protection Agency (EPA) ambient aquatic life criteria for copper to site- and station-specific criteria, using the indicator procedure of the U.S. EPA guidelines for deriving site-specific water quality criteria. A water effect ratio of 1.0 was established using unpolluted upstream water, resulting in a site-specific criterion maximum concentration (CMC) and criterion continuous concentration (CCC) of 8.7 and 6.2 μg/L copper, respectively. Mean water effect ratios of 3.9 to 7.0, reflective of reduced biological availability and/or toxicity of copper, were determined for four successive downstream stations where the water contained copper and other industrial and domestic wastes. The resulting station-specific CMCs and CCCs ranged from 32 to 57 and 22 to 39 μg/L copper, respectively. These copper criteria were compared with effluent-contributed ambient copper concentrations and ecological survey data from each downstream station to ascertain impact on aquatic life. It was concluded that the national and site-specific criteria derived for copper would be protective of the river's aquatic life because a relatively healthy aquatic community existed where these criteria were exceeded slightly. Whether or not the station-specific criteria were protective could not be determined because these criteria were not exceeded at stations with healthy communities; however, where they were exceeded, impaired aquatic communities were evident.

Generally, C. dubia survival and young production data from receiving water tests and copper addition tests, conducted just prior to the acute toxicity tests, were also indicative of reduced copper biological availability and/or toxicity in the Naugatuck River at downstream stations.
A screen device to eliminate “floaters” in daphnia magna toxicity tests
Authors: Dean Janet H. , DeGraeve G. Michael
Published: March 2010

Daphnia magna are commonly trapped at the surface of test waters in D. magna toxicity tests. These “floaters” complicate interpretation of test results. A screen device was designed to physically prevent the Daphnia from touching the water surface. The effectiveness of the device was evaluated using several complex effluents.
Responses of estuarine macrofauna colonizing sediments contaminated with fenvalerate
Authors: Tagatz Marlin E. , Stanley Roman S. , Plaia Gayle R. , Deans Christine H.
Published: March 2010

Macrobenthic animal communities that colonized uncontaminated and fenvalerate-contaminated sand (0.1, 1 and 10 μg/g dry weight, nominal) in boxes placed for 8 weeks in an estuary were compared to assess effects of fenvalerate on community structure. As much as 27% of initial concentrations of this synthetic pyrethrin persisted in sediment at the end of the test. The average number of species (35.6) in communities in five replicates exposed to 10 μg/g was significantly less than that in the control (47.8) and lower concentrations (45.0 and 46.2). Of the dominant phyla collected (Annelida, Mollusca, Chordata and Arthropoda), abundance of chordates only (primarily lancelets, Branchiostoma caribaeum) was reduced by 10 μg fenvalerate/g. Biological indices applied to the data showed the greatest structural differences for communities exposed to the highest concentration, but these did not differ substantially from those for the control. Effective concentration for exposure via the sediment was five orders of magnitude greater than that for waterborne exposure determined in earlier benthic community studies.
Parameterization of predictive fate models: A case study
Authors: Reinert K. H. , Rocchio P. M. , Rodgers J. H.
Published: March 2010

Accurate prediction of chemical fate and persistence using general aquatic fate models requires model parameterization, i.e., the determination of site-specific environmental and chemical parameters for model input. The capability of one model, the Exposure Analysis Modeling System (EXAMS), to predict the fate of endothall, an aquatic herbicide, in a reservoir was compared using two different parameterization methods. The first method, limited parameterization, used only literature and limited field data. The second method, intensive parameterization, employed laboratory, experimental pool and field data. Differences of less than one order of magnitude were observed among the endothall fate predictions from EXAMS in this reservoir using either method. Predicted endothall aqueous half-lives were greater than the observed half-life by a factor of 5 to 9. Predicted endothall concentrations in sediment were consistently below the minimum detectable level (0.01 mg kg−1) for endothall, whereas endothall concentrations were measured in reservoir sediments in the field. In this case, the results indicate that limited parameterization of EXAMS provides predictions of endothall persistence that are as accurate as those provided by intensive parameterization, thus saving time and reducing costs. Limited parameterization produced relatively accurate predictions in this study, possibly because only one fate process, biotransformation, was important. For chemicals affected by numerous fate processes, the errors associated with each fate process input could significantly affect the accuracy of predictions.
Sensitivity analysis of population growth rates estimated from cladoceran chronic toxicity tests
Authors: Meyer Joseph S. , Ingersoll Christopher G. , McDonald Lyman L.
Published: March 2010

Four variables–mean brood size, day of first reproduction, longevity and per capita rate of increase (r)–were compared in four 70-d chronic toxicity tests in which Daphnia pulex were exposed to cadmium or copper in continuous and pulsed exposures. With these data we asked the question: Is the population-level variable (r) more sensitive than the three organism-level variables (mean brood size, day of first reproduction and longevity) as an indicator of toxicant stress? We define two variables to be equally sensitive if, for both variables, differences between treatments and the control have statistical significance levels in the same probability range. In these four tests, none of the four variables was consistently the most sensitive. We also evaluated the sensitivity of r by simulating shorter test durations, delays in reproduction and less frequent observation schedules. Simulated test durations of less than 21 d produced biased underestimates of r and increased coefficients of variation of the estimates of r relative to the 70-d values; simulated 1- and 2-d delays in reproduction also produced biased underestimates of r. However, estimates of r computed for a simulated Monday-Wednesday-Friday observation schedule did not differ significantly from estimates of r computed for a daily observation schedule. We conclude that although the estimator of per capita rate of increase is not always the most sensitive statistic that can be computed from cladoceran chronic toxicity test data, it can be useful for evaluating apparently conflicting effects of pollutants on survival and reproduction, as occurred in the copper continuous-exposure toxicity test.
PCB availability assessment of river dredging using caged clams and fish
Authors: Rice Clifford P. , White David S.
Published: March 2010

The effects of dredging to remove sediments contaminated with polychlorinated biphenyls (PCBs) were studied in the South Branch of the Shiawassee River in south-central Michigan. Caged fingernail clams, Sphaerium striatinum (Lamarck), and fathead minnows, Pimephales promelas Rafinesque, were used to monitor the bioavailability of PCBs, and these data were compared with changes in water column concentrations before dredging, during dredging and up to six months after dredging was completed. Monitoring of water, clams and fish during dredging confirmed that significant amounts of PCBs were released from the sediments. At all locations downstream and in the area of the dredging, there were increases in the availability of PCBs for at least six months. PCB concentrations in clams and fish in the dredged zone increased from 64.5 to 87.95 μg/g dry weight and from 13.82 to 18.30 μg/g dry weight, respectively, after dredging. Downstream (11 km), post-dredge uptake was also higher; however, clams showed less uptake than fish. This implied different uptake routes for the two organisms. There was no noticeable change in total PCB concentration in the water after dredging.

In situ experiments were run to determine uptake curves and time to uptake equilibrium for both clams and fish. Results of tests for equilibrium uptake by fatheads agreed with literature values. Uptake maxima occurred within 20 to 30 d. For clams, maximum uptake for Aroclor 1242 occurred after 9 d. Log bioconcentration factors for clams ranged from 2.6 to 4.5 for Aroclor 1242 and from 3.0 to 4.4 for Aroclor 1254; for fish, they ranged from 3.0 to 4.4 for Aroclor 1242 and from 4.5 to 5.5 for Aroclor 1254.
Use of respiratory-cardiovascular responses of rainbow trout (Salmo gairdneri) in identifying acute toxicity syndromes in fish: Part 2. malathion, carbaryl, acrolein and benzaldehyde
Authors: McKim James M. , Schmieder Patricia K. , Niemi Gerald J. , Carlson Richard W. , Henry Tala R.
Published: March 2010

An in vivo fish model was used to monitor the respiratory-cardiovascular responses of individual spinally transected rainbow trout exposed to acutely toxic aqueous concentrations of two acetylcholinesterase (AChE) inhibitors, malathion and carbaryl, and two mucous membrane irritants, acrolein and benzaldehyde. The most striking changes in respiratory-cardiovascular physiology noted on malathion and carbaryl exposures were immediate decreases in oxygen utilization (U) and heart rate (HR). Ventilation volume (VG) increased to compensate for the lower U, but not enough to increase oxygen consumption (VO2). Blood responses in carbaryl-exposed trout differed from those in the malathion group; there were increased hematocrit (Hct) and hemoglobin (Hb) values along with an extensive drop in arterial pH (pHa) and total arterial carbon dioxide (TaCO2). The overall respiratory-cardiovascular responses of the rainbow trout to acrolein and benzaldehyde intoxication represent a direct effect of the chemical at the respiratory surface. A steady increase in cough rate (CR) was recorded for fish exposed to both chemicals throughout exposures. A moderate to low increase in VG and VO2 was followed at 50 to 60% survival time by sudden decreases in VG and VO2 until death. Ventilation rate (VR), U and HR showed a steady downward trend over the entire survival period. After the midpoint in survival time, total arterial oxygen (TaO2), (TaCO2) and pHa all decreased, while Hct increased steadily. Individual principal components analyses of the cardiovascular-respiratory responses of fish exposed to the four chemicals showed that the variables were highly correlated and that the first two principal components explained 55 to 70% of the variation in the 18 parameters analyzed. A two-dimensional diagram of the first two principal components illustrated this multivariate response and the increased variability in the responses of exposed fish as compared with the control fish. Sets of toxic responses were developed to describe two new fish acute toxicity syndromes (FATS), one for AChE inhibitors and one for respiratory irritants. These were combined with the FATS for respiratory uncouplers and narcotics from previous work prior to discriminant function analysis (DFA). DFA was used to predict the specific FATS for a chemical based on the cardiovascular-respiratory responses observed during intoxication. DFA on these responses resulted in a 100% correct separation of four specific FATS for all 32 trout tested. Of the 18 responses monitored and used in the DFA, CR, VO2, TaO2, pHa and U were the best discriminators in predicting the correct FATS for each fish.
Root elongation method for toxicity testing of organic and inorganic pollutants
Authors: Wang Wuncheng
Published: March 2010

Cucumber and lettuce are the biological test species recommended by the U.S. Environmental Protection Agency, the Food and Drug Administration and the Organization for Economic Cooperation and Development for toxicity testing and environmental assessment. Millet is a riverine species widely distributed in the Midwest. The Illinois State Water Survey has conducted several studies using this species and the results show the millet to be rather promising for toxicity testing.

The objective of this study was to compare the responses of lettuce, cucumber and millet seeds to heavy metals, including Cd, Cr(VI), Cu, Mn, Ni and Zn. Lettuce was most sensitive to metal toxicity, while results for cucumber and millet were mixed. The millet seeds, however, did show a predictable pattern of response similar to their response to phenolic toxicity. There was a fairly good correlation between 50% effect concentrations and no observed effect concentrations for millet (R2 = 0.858).

Lettuce and millet seeds are recommended for use together in toxicity tests of unknown, complex hazardous substances.
Reproduction in mallards fed selenium
Authors: Heinz Gary H. , Hoffman David J. , Krynitsky Alexander J. , Weller Deborah M. G.
Published: March 2010

Mallards (Anas platyrhynchos) were fed diets containing 1, 5, 10, 25 or 100 ppm selenium as sodium selenite, a diet containing 10 ppm selenium as seleno-DL-methionine or a control diet. There were no effects of 1, 5 or 10 ppm selenium as sodium selenite on either weight or survival of adults or on reproductive success, and there did not appear to be a dose-response relationship at these lower levels. The 100 ppm selenium diet killed 11 of 12 adults; one adult male fed 25 ppm selenium died. Selenium at 25 and 100 ppm caused weight loss in adults. Females fed 25 ppm selenium took longer to begin laying eggs and intervals between eggs were longer than in females in other treatment groups. Hatching success appeared to be reduced in birds fed 10 ppm selenium as selenomethionine, but the reduction was not statistically significant. The survival of ducklings and the mean number of 21-d-old ducklings produced per female were reduced in the 25 ppm selenium as sodium selenite group and the 10 ppm selenium as selenomethionine group. Egg weights were not affected by any selenium treatment, but 25 ppm selenium lowered the Ratcliffe Index. Duckling weights at hatching and at 21 d of age were reduced 28 and 36%, respectively, in birds fed 25 ppm selenium, as compared with controls. Body weights measured on day 21 were lower for ducklings fed 10 ppm selenium as selenomethionine than in some other groups. Selenium in concentrations of 10 and 25 ppm as sodium selenite caused mainly embryotoxic effects, whereas 10 ppm as selenomethionine was more teratogenic, causing hydrocephaly, bill defects, eye defects (microphthalmia and anophthalmia) and foot and toe defects, including ectrodactyly. Selenomethionine was much more readily taken up by mallards and passed into their eggs than was sodium selenite, and a greater proportion of the selenium in the eggs ended up in the white when selenomethionine was fed. Adult males accumulated more selenium than did females, probably because of the females' ability to eliminate selenium in their eggs.
Effects of aniline and three derivatives on laboratory microecosystems
Authors: Yount J. David , Shannon Lyle J.
Published: March 2010

Generic mixed-flask microcosms were used to evaluate ecosystem responses to aniline and three closely related compounds—2,6-diisopropylaniline, 4-hexyloxyaniline and 2,3,5,6-tetrachloroaniline. Toxicity was determined on both an acute and chronic basis using changes in ecosystem-level variables (pH and dissolved oxygen levels) as indicators of effect. These calculated toxicity values were then compared with reported toxicity data on bacteria, algae, protozoa and Cladocera to evaluate the relative sensitivity of the method. The relative toxicities of the tested compounds were the same in microcosm tests as in the available single-species tests, but the range between the most and least toxic as determined by the microcosm test was smaller by an order of magnitude. Aniline was the least toxic, followed, in order of increasing toxicity, by 2,6-diisopropylaniline, 4-hexyloxyaniline and 2,3,5,6-tetrachloroaniline. The minimum effect concentrations determined for these compounds were generally lower than reported literature values, suggesting that the method does not sacrifice sensitivity in providing an integrated picture of ecosystem-level effects.
Dynamics of hydrophobic organic chemical bioconcentration in fish
Authors: Gobas Frank A. P. C. , MacKay Donald
Published: March 2010

A model is presented describing the kinetics of uptake and release of nonmetabolizing organic chemicals by fish from water. The model contains three parameters: a bioconcentration factor which is specific to the chemical (and can be characterized by the octanol/water partition coefficient and fish lipid content), a water-phase resistance term and a lipid-phase resistance term which are specific to the fish. These parameters can be estimated from uptake-clearance experiments. Part of the water-phase resistance term can be attributed to gill ventilation rate as estimated from gill uptake efficiencies and part is an “internal” resistance. Procedures are suggested for scaling these parameters to different fish sizes. The dependence of these resistances, and uptake and clearance rate constants, on chemical hydrophobicity is discussed and quantified.
Effects of chemical structure and exposure on the microbial degradation of polycyclic aromatic hydrocarbons in freshwater and estuarine ecosystems
Authors: Heitkamp Michael A. , Cerniglia Carl E.
Published: March 2010

The microbial mineralization of six polycyclic aromatic hydrocarbons (PAHs), containing two to five fused benzene rings, and hexadecane were investigated in sediment: water microcosms which modeled degradation in two freshwater and one estuarine ecosystem. A ranking of the PAHs by order of mineralization rates along with calculated half-lives (range in weeks) are as follows: naphthalene (2.4-4.4) ≥ hexadecane (2.2-4.2) > phenanthrene (4-18) > 2-methylnaphthalene (14-20) > pyrene (34->90) ≥ 3-methylcholanthrene (87->200) ≥ benzo[a]pyrene (200->300). PAH residues persisted from two to over four times longer in a pristine ecosystem than in an ecosystem chronically exposed to low levels of petroleum hydrocarbons. The mineralization of higher-molecular-weight PAHs (> four rings) totaled 0.2 to 6.5% after 8 wk. Relative differences in PAH mineralization among the ecosystems were related to hexadecane mineralization rates, the occurrence and concentration of aromatic hydrocarbon residues in sediments, and elevated populations of hydrocarbon-degrading microorganisms. Total heterotrophic microbial populations were not good indicators of PAH mineralization rates. Chemical analyses of residues in the microcosms detected the presence of extractable polar metabolites in water and sediments which accounted for 0.1 to 6% of the original PAHs.
Effects of experimental manipulation of environmental factors on phenol mineralization in soil
Authors: Thornton-Manning Janice R. , Jones Daniel D. , Federle Thomas W.
Published: March 2010

The effects of temperature and nitrogen, phosphorus, and carbon enrichments on phenol mineralization were determined in the uppermost and deepest horizons of two contrasting soils. Soil samples were amended with trace levels of 14C-phenol and incubated under various experimental conditions. Mineralization was determined by measuring the production of 14CO2 with time. First-order rate constants (k) and extent of mineralization (PO) were estimated from the resulting data using nonlinear regression. Temperature affected mineralization differently as a function of soil type. While not stimulating mineralization in the upper horizons, nitrogen and phosphorus enrichment resulted in faster and more extensive mineralization in the subsurface horizons. Carbon (cellulose) enrichment had little effect in any soil examined. This study demonstrates the importance of temperature and inorganic nutrient availability in controlling the biodegradation of a model pollutant in surface and subsurface soil. It further illustrates the variability that exists between soil types and between different horizons of the same soil type as to factors capable of influencing biodegradation processes.
Effects of hydrogen fluoride on incorporation and transport of photoassimilates in soybean
Authors: Madkour Samia , Weinstein Leonard H.
Published: March 2010

The effect of hydrogen fluoride (HF) on the translocation and partitioning of 14C between transport and nontransport photoassimilates from source leaves to sink regions was studied. Soybean plants (Glycine max (L.) Merr. cv ‘Hodgson 78’) were fumigated continuously with HF at 0, 1, and 5 μF-m−3 for 8 to 10 d at three stages of development (vegetative, flowering and early fruit set, and pod filling). The second fully expanded trifoliolate leaf of experimental plants was exposed to 14CO2.

In plants exposed to HF, there was an increased retention of 14C-labelled assimilates in foliage (source tissue), accompanied by a reduced export of these compounds to other plant parts (path and sink tissues). There was also a greater incorporation of 14C into nontransport ethanolinsoluble assimilates at the expense of the ethanol-soluble transport assimilates in source leaves. When compared with control plants, exposure to HF also increased the proportion of 14C incorporated into sugars in source leaves accompanied by a decrease in 14C-sugars in sink tissues.

Results suggest that the retention of sugars in source leaves and the reduction in allocation to sink tissue may be a result of the inhibition of the process involved in the export of sugars from the leaf (i.e., phloem loading). An inhibition of phloem loading may result in an accumulation of sugars in the mesophyll cells, which may exhibit feedback inhibition on starch degradation and/or stimulation of starch synthesis.
The relationship of life history attributes to toxicant tolerance in fishes
Authors: Neuhold John M.
Published: March 2010

The relationship between tolerance to toxicants and fish species longevity, maximum weight attained, and fecundity is demonstrated. It is concluded that among species longevity and maximum weight attained is negatively related to tolerance to toxicants, while fecundity is positively related to toxicant tolerance. It is also concluded that mode of action of toxicants is related to longevity and fecundity among species.
Comparison of the EC50s of algal toxicity tests calculated by four methods
Authors: Walsh Gerald E. , Deans Christine H. , McLaughlin Leslie L.
Published: March 2010

EC50s (calculated concentrations that would inhibit growth by 50%) of 21 pesticides in unicellular algal toxicity tests were calculated by straight-line graphical interpolation, moving average interpolation, prohibit analysis, and the binomial method. EC50s of 18 tin compounds were calculated by graphical interpolation, moving average, and probit methods. Results from a total of 187 tests were analyzed. The EC50 values were essentially identical when calculated by each method. Although moving average and probit analyses allow calculation of confidence intervals, there is doubt that they can be used with the quantitative data of algal toxicity tests. In the absence of confidence intervals, only the calculated EC50 is used to express relative toxicity, and straight-line graphical interpolation, a simple and rapid method, may be used in lieu of more complex statistical methods.
Degradation of selected halogenated ethanes in anoxic sediment-water systems
Authors: Jafvert Chad T. , Lee Wolfe N.
Published: March 2010

The degradation of selected halogenated ethanes was studied in anoxic sediment-water suspensions at 1 to 20% sediment concentrations. Batch kinetic experiments were used to quantify decay. Eh measurements of all suspensions were below -100 mV (vs SHE), indicating reduced environmental conditions. Hexachloroethane (HCA), 1,1,2,2-tetrachloroethane (TTCA), 1,2-diiodoethane (DIA) and 1,2-dibromoethane (DBA) were degraded within minutes to days, but 1,2-dichloroethane (DCA) remained in the system through 35 d, at which point the study was ended. The major route of transformation of these compounds in this system was vicinal dehalogenation. Rates of disappearance followed pseudo-first-order kinetics at low reactant concentrations and high sediment concentration. The order of reactivity in the same sediment sample followed the sequence, HCA ⋍ DIA > DBA > TTCA > DCA.
Assessment of contamination of fish by water-soluble fractions of petroleum: A role for bile metabolites
Authors: Hellou Jocelyne , Payne Jerry F.
Published: March 2010

Several conjugated metabolites were found to accumulate in the gall bladder bile of trout (Salmo gairdneri) exposed to No. 2 fuel oil, but no free metabolites could be detected. GC-MS analysis of the major resolved components resulted in the identification of at least eight metabolites, present as alcohols. Single-ion monitoring MS indicated the predominance of a fragment at m/e 152, and 1H-NMR spectroscopy provided information on the average structure of the mixture of hydrolyzed metabolites. The study demonstrated that focusing on specific two- and three-ring conjugated metabolites in the gall bladder bile of fish can provide a simple and rapid investigative tool for the monitoring and assessment of petroleum and fuel oil pollution.
Subcellular distribution and binding of cadmium to metallothionein in tissues of rainbow trout after exposure to 109Cd in water
Authors: Olsson Per-Erik , Hogstrand Christer
Published: March 2010

The uptake and distribution of cadmium in rainbow trout (Salmo gairdneri) was studied after 1 week of exposure to 109Cd in water and after a subsequent 14-week period in clean water. The major target organs, that is, gills, kidney, liver and intestine, were analyzed for 109Cd content and the subcellular distribution of cadmium determined. A successive redistribution of cadmium from the gills and intestine to the liver and kidney was observed. Sephadex G-75 chromatography of the organs revealed that most of the cadmium was found in the metallothionein-containing peak and that the amount of cadmium in this peak increased over time after the exposure. Ion-exchange chromatography on fast protein, polypeptide and polynucleotide liquid chromatography of the metallothionein-containing peaks revealed that 109Cd eluted together with copper and polaro-graphic activity. There was no evidence that other low-molecular-weight cadmium-binding proteins were present in the organs. These results indicate that the metallothionein in rainbow trout binds cadmium after the fish are exposed to the metal in water.
Residues of dimethioate and methomyl on tomato and cabbage in relation to their effect on quality-related properties
Authors: Othman Mohamed A. , Antonious G. F. , Khattab Marium M. , Abdel-All A. , Khamis Awatef E.
Published: March 2010

Dimethoate EC 40% and methomyl 90% WSP were applied under field conditions to follow up the decline of their residues on tomato and cabbage plants. The results indicate that the level of dimethoate and methomyl residues were found to be below tolerance level after 7 and 3 d from application, respectively. Dimethoate and methomyl residues also had significant effects on ascorbic acid contents in tomato fruits after 1 and 7 d for dimethoate, while the effect was after 3 and 10 d for methomyl. Dimethoate also showed significant effects on total soluble solids in tomato fruits presented until 14 d after pesticide application. Both dimethoate and methomyl had significant effect on both iron and magnesium content in tomato fruits and leaves and cabbage leaves during the 14 d.
Bioaccumulation of trace organic contaminants from sediment by baltic clams (Macoma balthica) and soft-shell clams (Mya arenaria)
Authors: Foster Gregory D. , Baksi Sandra M. , Means Jay C.
Published: March 2010

Sediment from Chesapeake Bay was fortified with naphthalene-d8, diphenyl-d10 ether, di-n-octyl phthalate-2,3,4,5-d4, p,p-DDT-d8 and chrysene-d12 to measure the bioaccumulation of sediment-sorbed chemicals by baltic clams (Macoma balthica) and soft-shell clams (Mya arenaria). Macoma bioaccumulated the deuterated chemicals from sediment at measurable rates. Uptake transfer coefficients were derived from bioaccumulation, and for Macoma they ranged from 4.95 × 10−2 h−1 for diphenyl-d10 ether to 1.47 × 10−3 h−1 for chrysene-d12. Transfer coefficients for Macoma were inversely related to the water solubilities of the sorbed chemicals. Mya did not show bioaccumulation of the sediment-sorbed chemicals. Bedded sediments contaminated with trace organic chemicals may be a relevant source of exposure to toxicants in estuarine habitats for depositfeeding bivalves.
Evaluation of the developmental toxicity of metal-contaminated sediments using short-term fathead minnow and frog embryo-larval assays
Authors: Stebler Elaine F. , Burks Sterling L. , Bantle John A. , Dawson Douglas A.
Published: March 2010

The effects of metal-contaminated sediment extracts and a reference toxicant (zinc sulfate) were determined by examining the developmental morphology, growth and mortality of exposed fathead minnow (Pimephales promelas) and frog (Xenopus laevis) embryos. Sediments from two contaminated stream sites were extracted with reconstituted culture water at various pH values for 24 h. Developmental toxicity tests were performed using the frog embryo teratogenesis assay-Xenopus (FETAX) protocol. The results suggest that Zn was the major developmental toxicant in the sediment extracts. The measured Zn concentration in the sediment extracts that caused malformation in 50% of the fish embryos (EC50) was 0.5 to 1.4 mg/L (normalized to 100 mg/L hardness). EC50 values for the reference toxicant tests were 0.6 and 0.8 mg/L Zn. The frog embryo EC50 for the extracts ranged from 2.2 to 3.6 mg/L Zn and was 3.6 mg/L Zn in the reference toxicant test. In 67% of the tests, malformation was a more sensitive endpoint than growth inhibition. Mortality was the least sensitive endpoint, that is, the LC50s in the reference toxicant tests were 3.6 mg/L Zn for the fathead minnow and 34.5 mg/L for the frog. The extraction procedure may be useful for determining potential toxicity in the event metals are leached from aquatic sediments by dredging or acidification.
Acute and chronic effects of tributyltin on a chesapeake bay copepod
Authors: Hall Lenwood W. , Bushong Steven J. , Hall W. Scott , Johnson W. Edward
Published: March 2010

One 72-h acute and two 13-d chronic flow-through tributyltin (TBT) toxicity experiments were conducted with the estuarine zooplankter Eurytemora affinis. The 48-h and 72-h LC50s were 2.2 and 0.6 μg/L TBT, respectively, based on measured concentrations. TBT concentrations of 100 ng/L significantly reduced the survival of neonates (young) after 6 d of exposure in the first chronic experiment. Significant adverse effects were not reported at TBT concentrations ranging from 12.5 to 100 ng/L in the second chronic test. However, a significant adverse effect was noted at 200 ng/L in that test. TBT concentrations reported in various marina areas of the northern Chesapeake Bay exceed toxic concentrations found for E. affinis in these laboratory studies.
Toxicity and bioconcentration of 2,3,7,8-tetrachlorodibenzodioxin and 2,3,7,8-tetrachlorodibenzofuran in rainbow trout
Authors: Mehrle Paul M. , Buckler Denny R. , Little Edward E. , Smith Larry M. , Petty Jim D. , Peterman Paul H. , Stalling David L. , De Graeve G. M. , Coyle James J. , Adams William J.
Published: March 2010

Among the most toxic isomers of polychlorinated dibenzodioxins and polychlorinated dibenzofurans, two groups of toxic aromatic compounds, are 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF). We examined the chronic toxicity of these compounds to rainbow trout (Salmo gairdneri). The fish (0.38 ± 0.09 g) were continuously exposed in an intermittent-flow proportional diluter for 28 d to 0, 38, 79, 176, 382, and 789 pg TCDD/L (parts per quadrillion) or to 0, 0.41, 0.90, 1.79, 3.93, and 8.78 ng TCDF/L (parts per trillion); exposures to each chemical were followed by a 28-d depuration phase. TCDD had significant effects on survival, growth, and behavior during the exposure and depuration phases. The no observed effect concentration was lower than the lowest exposure concentration of 38 pg/L. The average measured BCF at 28 days was 26,707. The estimated bioconcentration factor at steady-state equilibrium was 39,000 in the lowest exposure concentration where fish were least affected. TCDF, like TCDD, induced similar effects on survival, growth and behavior. The no observed effect concentration, based on survival, was 1.79 ng/L; that based on growth was 0.41 ng/L. The measured bioconcentration factor was 6,049 in fish exposed to 0.41 ng/L, and 2,455 in fish exposed to 3.93 ng/L for 28 d.