bluuebunny/crossref_metadata_2025 huggingface dataset:
Volatilization rates of selected haloforms from aqueous environments
Authors: Kaczmar Swiatoslav W. , D'Itri Frank M. , Zabik Matthew J.
Published: March 2010

Ratios of the gas transfer rate constants of oxygen to the haloforms CHC13, CHC12Br, CHC1Br2 and CHBr3 were measured and used to calculate an aqueous half-life range for each compound. The calculated half-lives suggest that production and release of haloforms as a result of chlorination of wastewater should not cause these materials to accumulate in the aquatic environment.
Acute toxicity of diazinon is similar for eight stocks of bobwhite
Authors: Hill Elwood F. , Camardese Michael B. , Heinz Gary H. , Spann James W. , Debevec Antonia B.
Published: March 2010

Nine-week-old bobwhite (Colinus virginianus) from eight different game farms were tested for their sensitivity to an acute oral exposure of technical-grade diazinon (phosphorothioic acid O,O-diethyl-O-[6-methyl-2-(l-methylethyl) -4-pyrimidinyl]ester). Extraneous variables associated with interlaboratory differences in husbandry were eliminated by incubating eggs and rearing chicks to test age for all stocks simultaneously in the same facilities at the Patuxent Wildlife Research Center. Under this single set of conditions, the responses of the eight stocks of bobwhite to diazinon were statistically inseparable, with LD50 values varying from 13 mg/kg (95% confidence interval, 8–21 mg/kg) to 17 mg/kg (95% confidence interval, 11–25 mg/kg). The pooled LD50 for the eight stocks was 14.7 mg/kg (95% confidence interval, 13.1–16.5 mg/kg).
An environmental hazard evaluation of uranium in a Rocky Mountain stream
Authors: Parkhurst Benjamin R. , Elder Robert G. , Meyer Joseph S. , Sanchez Deborah A. , Pennak Robert W. , Waller William T.
Published: March 2010

Uranium mining is an important industry in the Rocky Mountain region; however, little is known about the environmental hazards of uranium to fish and other aquatic organisms.

Indian Creek, a hard-water stream (200 mg/L as CaCO3) near Gunnison, Colorado, receives periodic discharges of runoff from a uranium mine. In addition, natural springs contribute uranium to the creek. As a result, uranium concentrations in the creek range up to 4 mg/L, concentrations which are potentially toxic to trout based on published toxicity data. Therefore, we conducted a series of studies to analyze the potential toxicity and bioaccumulation of uranium in Indian Creek and downstream waters.

A 60-d post-hatch, early life stage toxicity test was conducted with brook trout in water of hardness and alkalinity similar to Indian Creek. Additional tests were performed in soft and hard water (96-h acute toxicity tests) and in water of Indian Creek's quality (48-h acute toxicity tests). Trout from the 60-d test were also analyzed for uranium bioaccumulation. To confirm the results of the laboratory studies, these data were compared with on-site field study data, including surveys of fish and benthic invertebrates, and analyses of uranium levels in trout. The laboratory results indicated that the high hardness and alkalinity of the test water greatly reduced the potential toxicity of uranium to trout. Concentrations estimated to be chronically toxic from the early life stage test were greater than 9 mg/L; whereas the 48-h LC50 was 59 mg/L. Bioconcentration factors for uranium were low, ranging from 1.9 to 4.3.

Benthic invertebrate and fish studies conducted in Indian Creek confirmed that current uranium concentrations are not significantly toxic to resident aquatic biota. In-stream bioaccumulation of uranium is also very low, and is comparable to the laboratory-derived values.

Our study demonstrated that laboratory toxicity and bioaccumulation tests can accurately evaluate potential in-stream hazards of uranium. To accurately estimate in-stream toxicity and bioaccumulation of metals, it is important that laboratory tests simulate in-stream water quality.
Planimetric analysis of redear sunfish (Lepomis microlophus) hepatopancreas following selenium exposure
Authors: Sorensen Elsie M. B. , Bauer Thomas L.
Published: March 2010

A real ratios of pancreas cells to liver cells (P/L ratios) were determined planimetrically and compared with selenium accumulated in the hepatopancreas (liver and associated exocrine pancreas) of redear sunfish (Lepomis microlophus). Fish were collected from four locations in Martin Lake, Texas, and from a reference lake 8 km upstream in the same drainage system. Fish collected from selenium-contaminated areas in Martin Lake had significantly higher P/L ratios than did reference fish. The increase in the P/L ratios could be explained by either pancreatic cell hyperplasia or parenchymal hepatocyte necrosis and cell loss. Since a previous publication documented both central necrosis with loss of parenchymal hepatocytes and architectural disorganization and endoplasmic reticulum changes in the exocrine pancreas cells of these same redear sunfish, both changes probably occurred simultaneously. However, in this study, P/L ratios were not correlated with selenium levels in the hepatopancreas. This contrasts with published data regarding hematological changes, condition factors, and relative hepatopancreas weight for the same redear sunfish collected for this study. Relative ratios of pancreatic cells to liver cells determined in this study, therefore, were less accurate in pinpointing biological changes due to selenium than were the other parameters previously published using these same fish.
Laboratory sediment toxicity tests, sediment chemistry and distribution of benthic macroinvertebrates in sediments from the keweenaw waterway, michigan
Authors: Malueg K. W. , Schytema G. S. , Krawczy D. F. , Gakstatter J. H.
Published: March 2010

Acute laboratory sediment toxicity tests using the water flea Daphnia magna and the burrowing mayfly nymph Hexagenia limbata were conducted on sediments from two areas of the Keweenaw Waterway, Michigan, to determine whether the tests reflected the condition of benthic macroinvertebrate communities. The organisms were tested simultaneously in a recirculating bioassay chamber in which Daphnia were tested during the first two and last two days of a 10-d Hexagenia test. Sediment from the northern, copper-impacted portion of the waterway was generally acutely toxic to Daphnia, but not to Hexagenia, while sediment from the southern, less-impacted portion was not toxic to either organism. Positive relationships existed between organism mortality, copper content of the sediment and field distribution of macroinvertebrates.
Measurement of median lethal dose as a rapid indication of contaminant toxicity to fish
Authors: Hodson P. V. , Dixon D. G. , Kaiser K. L. E.
Published: March 2010

A new method was developed to rapidly measure the toxicity of contaminants to fish over 96 h. The method is the measurement of median lethal doses by intraperitoneal injection (IP-LD50). Contaminants are dissolved in 5% ethanol in saline or in cod-liver oil and injected at a rate of 1.0 ml per 100 g of fish.

The results of parallel bioassays to measure toxicity by oral intubation (OI-LD50) or aqueous exposure (LC50) were closely linked to IP-LD50 values. The coefficient of determination (r2) for a linear regression between IP-LD50 and OI-LD50 values was 0.99. In contrast, the r2 between IP-LD50 and LC50 values was lower (0.44) and the regression curvilinear. However, r2 improved to 0.82 when LD50 values were divided by the logarithm of the octanol-water partition coefficient (log P). Therefore, some of the differences in toxicity between chemicals may be due to interactions between their lipid (or water) solubilities and their rate of uptake by fish.

The IP-LD50 values of five chemicals varied with the carrier used; toxicity was lower for the oil carrier compared to injections with 5% ethanol in saline. The magnitude of the difference varied with the chemical tested, so that the two measures of toxicity did not appear to be related. However, the relationships again improved when the IP-LD50 (oil) was divided by log P.

The measurement of IP-LD50 values was faster, simpler and less expensive than traditional LC50 bioassays. The use of IP-LD50 values to screen chemicals for their relative toxicity to fish will save time and money without any real loss in the relevance of conclusions. We propose their use for research on environmental quantitative structure-activity relationships.
The acute toxicity of picloram, picloram potassium salt, and picloram triisopropanolamine salt to aquatic organisms
Authors: Mayes Monte A. , Dill D. C.
Published: March 2010

The toxicity of technical picloram acid (93.8% active ingredient), picloram potassium salt (43.5% active ingredient) and picloram triisopropanolamine salt (65.2% active ingredient) to aquatic organisms was evaluated in static acute toxicity tests. Species tested were the fathead minnow (Pimephales promelas Rafinesque), rainbow trout (Salmo gairdneri Richardson), bluegill (Lepomis macrochirus Rafinesque), and the daphnid (Daphnia magna Straus). The rainbow trout was the most sensitive species tested with 96-h LC50 values of 19.3, 48 and 51 mg/L for picloram acid, picloram potassium salt and picloram triisopropanolamine salt, respectively. These values are 36 × greater than the amount of picloram detected in freshwater streams following the application of picloram to experimental watersheds.
Rainbow trout bioconcentration of some halogenated aromatics from water at environmental concentrations
Authors: Oliver Barry G. , Niimi Arthur J.
Published: March 2010

The bioconcentration of 10 brominated and chlorinated aromatics by rainbow trout at ng/L concentrations, approaching environmental levels, has been studied. Seven of the compounds (3,4-dichlorobenzotrifluoride; 2,4,5-trichlorotoluene; 2,3,4-trichloroanisole; 1,4-dichloronapthalene; 1,3-dibromobenzene; 1,3,5-tribromobenzene; 1,2,4-tribromobenzene) reached a steady equilibrium concentration in the fish over the 90 day study period. Fish residue levels for the other three compounds (2,4-dichlorodiphenyl-ether; 1,2,4,5-tetrabromobenzene; 4,4′-dichlorobiphenyl) continued to increase over the entire study period. A good linear correlation (r2 = 0.79) between log bioconcentration factor (BCF) and log octanol-water partition coefficient (K) was found for the seven equilibrated compounds with a slope of 0.99. A good correlation between log BCF and parachor was also found for selected chemicals from this and an earlier study. Compounds that did not equilibrate plotted well below the log BCF versus log K line and had K values of > 105 and parachors (surface tension corrected molar volumes) > 400.
Toxicity of sediments from three metal-contaminated areas
Authors: Malueg K. W. , Schuytema G. S. , Gakstatter J. H. , Krawczyk D. F.
Published: March 2010

Sediments from Phillips Chain of Lakes (Wisconsin), Torch Lake (Michigan), and Little Grizzly Creek System (California) were tested for acute toxicity using the water flea, Daphnia magna, and the burrowing mayfly nymph, Hexagenia limbata. The organisms were tested simultaneously in a laboratory recirculating bioassay apparatus; Daphnia were tested during the first two (Daphnia I) and the last two (Daphnia II) days of 10-d Hexagenia tests.

Sediment from one of six sampling locations from the Phillips Chain of Lakes was toxic to Daphnia I, but not Daphnia II. None of these sediments was toxic to Hexagenia.

Contaminated sediments from Torch Lake and the Little Grizzly Creek System were highly toxic to Daphnia I and II, and Hexagenia.

In general, numbers of organisms, biomass, species diversity and dominant types of organisms correlated with metal content and acute laboratory toxicity.
Structure-activity relationship studies on the toxicities of benzene derivatives: I. An additivity model
Authors: Hall Lowell H. , Kier Lemont B. , Phipps Gary
Published: March 2010

A quantitative structure-activity analysis was performed on a series of substituted benzenes for which toxicity values have been obtained over 96 h in the fathead minnow. We have determined the additive contribution of several substituent groups. We have found a decreasing contribution to toxicity to be Cl > Br > NO2 > CH3 > OCH3 > NH2 > OH. This additivity model, expressed as an equation, yields a correlation coefficient (r) of 0.951, compared with the log of the lethal concentration (LC50). The positional dependence of substituents on benzene has been studied, as has the relationship between the substituent toxicity ranking and physical properties.
Organochlorine residues in eggs of black-crowned night herons from colorado and wyoming
Authors: McEwen Lowell C. , Stafford Charles J. , Hensler Gary L.
Published: March 2010

Eggs of black-crowned night-herons Nycticorax nycticorax (L.) were collected for analysis from seven nesting sites in Colorado and Wyoming in 1979. One egg was taken per nest from as many as 20 nests per site during early incubation. The nests were marked and revisited after hatching, but before fledging, to record the number of live young. DDE was detected in all of the collected eggs (total 147) at a mean concentration of 3.1 ppm, fresh basis (residue means are geometric). Mean DDE at the seven sites varied from 1.8 to 7.6 ppm. Polychlorinated biphenyls (PCBs) were detected in 81 eggs (mean 1.0 ppm); the highest mean at any site was 2.2 ppm. Twelve other organochlorines were each detected in 1 to 30 eggs, usually at a concentration of > 1.0 ppm. Mean total organochlorines in the eggs from the seven sites ranged from 2.0 to 10.1 ppm and the median number of compounds per egg ranged from one to five. Eggshell thickness was negatively correlated (p > 0.001, r = – 0.585) with DDE levels in the 147 eggs. Average shell thickness (0.258 ± 0.030 mm) was 8.8% lower than the average thickness (0.283 ± 0.016mm) of 40 pre-DDT eggs from this region. The nesting sites with the highest DDE and total organochlorine residues in the eggs had the thinnest shells, produced the fewest young and had more nonviable eggs and dead young. At four of the seven sites, the average number of live young per nest was > 2.0, the minimum long-term mean required for population maintenance. The source of the contaminants found in the heron eggs in this study was not determined.
Toxicity of arsenite and arsenate to the marine macroalga Champia Parvula (rhodophyta)
Authors: Thursby Glen B. , Steele Richard L.
Published: March 2010

By a previously established test procedure that uses 4.5 μM phosphate in the medium, the marine red alga Champiaparvula (C. Agardh) Harvey was shown to be more sensitive to arsenite [As(III)] than to arsenate [As(V)]. Mature cystocarps (evidence of sexual reproduction) were formed when plants were exposed to 65 μg As(III)/L, but not when exposed to 95 μg As(III)/L. Three hundred micrograms As(III)/L was sufficient to kill C. parvula. Using the standardized test, plants grew just as well in 10,000 μg As(V)/L as they did in the controls; however, sexual reproduction did not occur at this concentration. Phosphate concentration up to 9.1 μM had little or no effect on As(III) toxicity. Arsenate toxicity, however, was inversely proportional to the amount of phosphate in the medium. In the absence of added phosphate, As(V) toxicity was similar to that of As(III), except plants were still alive at 1,076 μg As(V)/L (although they did not grow).
Behavioral effects of methyl parathion on social groups of bluegill (Lepomis macrochirus)
Authors: Henry Mary G. , Atchison Gary J.
Published: March 2010

The behavioral effects of three sublethal concentrations of methyl parathion on social groups of bluegill (Lepomis macrochirus) were examined. Consistently similar hierarchies were formed in all test groups, allowing for comparison both before and after toxicant administration. Significant increases in comfort movements and respiratory disruptions and decreases in aggressive behaviors were observed after methyl parathion was added to treatment tanks. Changes in the frequencies of the affected behaviors occurred primarily within the first 24 h of the treatment period. In every treatment, the most subordinate and dominant individuals were affected more pronouncedly than were intermediately ranked fish. Consequently, differential, contaminant-induced responses associated with rank should be considered when conducting bioassays and perhaps ultimately examined in the field when dealing with species which form social hierarchies. Examination of this factor could help clarify the relative roles of social stress and toxicant stress in producing an effect.
Field and laboratory evaluation of the influence of copper-diquat on apple snails in Southern Florida
Authors: Winger Parley V. , Imlay Marc J. , McMillan Wayne E. , Martin Thomas W. , Takekawa Jean , Johnson W. Waynon
Published: March 2010

The recent decline of apple snail (Pomacea paludosa) populations in canals surrounding Loxahatchee National Wildlife Refuge in southern Florida coincided with the use of copper-diquat for the control of the aquatic weed hydrilla (Hydrilla verticillata). Field and laboratory studies were designed to assess the effects of copper-diquat on apple snails, which are the primary food of the endangered snail kite Rostrhamus sociabilis (formerly known as the Everglade kite). Acute toxicities (96-h LC50 values) of Cutrine-Plus and Komeen (chelated formulations of copper) to immature apple snails were 22 and 24 μg/L, respectively. Diquat was toxic at a concentration of 1,800 μg/L and did not increase the toxicity of copper when the chemicals were used in combination. Evaluation of field samples indicated that copper concentrations were higher in detritus than in water, plants and mud, and that there was a gradient of copper concentration from the canal to the interior, the highest residues being in samples from the canal. Copper associated with detritus (up to 150 μg/g) had no effect on growth or survival of apple snails in field cage and tank studies. Also, field applications of copper-diquat to hydrilla had no effect on survival of caged adult and immature snails. Copper from field applications was rapidly taken out of solution by plants and organic material in the water and subsequently incorporated into the bottom detritus. Although the effects of repeated applications of copper-diquat and high body burdens of copper (accumulated during exposure to herbicidal treatment) on survival and reproduction of apple snails are not known, the information available indicates that treatment of hydrilla with copper-diquat was probably not responsible for the decline in the apple snail population. Application at recommended rates should pose no threat to these snails in the organically rich waters of southern Florida.
Toxicity of copper-spiked sediments to freshwater invertebrates
Authors: Cairns Michael A. , Nebeker Alan V. , Gakstatter Jack H. , Griffis William L.
Published: March 2010

Natural freshwater sediments from two Oregon sites were spiked with copper in the laboratory and two static toxicity tests were conducted with series of copper concentrations ranging from 59 to 10,600 mg/kg of dry sediment. Water (800 ml) was added to 1-liter test beakers over the sediment (200 ml) and repeatedly removed and replaced to lower the aqueous copper concentrations. When copper concentrations stabilized, i.e., attained equilibrium between water and sediment, the midge Chironomus tentans, the cladoceran Daphnia magna and the amphipods Hyalella azteca and Gammarus lacustris were introduced as test animals in solid-phase sediment toxicity bioassays. Based on dry-weight sediment copper concentrations, LC50 values (48-h for Daphnia, 10-d for other organisms) ranged from 681 to 2,296 mg/kg.
Effects of chronic exposure to coal-derived oil on freshwater ecosystems: I. Microcosms
Authors: Franco P. J. , Giddings J. M. , Herbes S. E. , Hook L. A. , Newbold J. D. , Roy W. K. , Southworth G. R. , Stewart A. J.
Published: March 2010

Sixteen 67-liter freshwater microcosms were treated for 8 weeks with an unrefined coal-oil in amounts ranging from 0.03 to 7 ml per week. Phenols make up 95% of the water-soluble compounds in this oil, and dissolved phenol concentrations averaged <0.01 mg L−1 in the lowest dose and 10 mg L−1 in the highest. The microcosms were severely damaged at the highest treatment level; macrophytes, zooplankton and insects were eliminated, and the ecosystems became anaerobic. Microcosms did not recover to pretreatment conditions within 5 months. At lower dosages there were temporary effects on ecosystem metabolism, water chemistry and community structure. The most sensitive indices—community respiration, production/respiration ratio, pH and cladoceran zooplankton numbers—were affected at phenol concentrations below the lowest observable effect concentration of a chronic Daphnia magna bioassay.
Aerobic and anaerobic soil degradation of a hexahalocyclohexane mixture
Authors: Lickly Tim D. , Rhinehart Wayne L. , Murphy Patrick G. , Mendoza Celia G.
Published: March 2010

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

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

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

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

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

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

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

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

Various laboratory methods and mathematical models are being developed to assess the hazards of chemicals to aquatic environments. Although the approach is generally accepted, many of the methods and models have not been validated by comparison with field observations. In this study we compared predictions of the fate and biological effects of a reference compound, pentachlorophenol (PCP), with observations in experimental outdoor ponds. PCP was repeatedly applied to the subsurface water of three ponds with the aim of maintaining an average concentration of 50 to 100 μg/L in the water for a period of 30 d. At this dosage level chronic toxicity to some organisms was expected.

Evaporation, sorption, hydrolysis, biodegradation and indirect phototransformation of PCP were expected to be of minor importance under the environmental conditions encountered in the ponds. The partition coefficient of PCP between water and wet sediment was predicted to be near unity and the dominant loss process to be direct phototransformation. The rate of this process was calculated using the SOLAR mathematical model. Data used for this calculation were the light absorption spectrum of PCP, the quantum yield for the light-activated reaction, depth and light attenuation of pond water, season and latitude. After correcting for cloud cover, the calculated rate constant was 0.23 to 0.46 d−1. In good agreement with the calculations, the observed rate of loss was 0.15 to 0.34 d−1, and there was no evidence of accumulation in sediment.

The results of chronic toxicity tests with various species of fish, two species of snail and the planktonic crustacean Daphnia magna Straus were consistent with field observations. Chronic toxicity to filamentous algae (Chara sp. and Enteromorpha sp.) was observed in the field, and their death and decay were responsible for depression of dissolved oxygen concentrations and fish deaths. Direct effects on filamentous algae and the indirect effects caused by their death and decay could not be predicted in the absence of relevant laboratory data.
Detoxification rates of chlorinated solutions as determined by the half-life of biological activity with Daphnia magna
Authors: Doherty Francis G.
Published: March 2010

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

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

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

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

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

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

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

While great strides have been made in recent years regarding water quality criteria and hazard assessment of chemicals in the aquatic environment, the same is not true for the terrestrial ecosystem. This results in part from the magnitude of the problem and, perhaps, to some degree, from an attitude held by some that animals dwelling in and on the land can better cope with environmental stress than can their aquatic counterparts. Indeed, this sometimes may be the case, but results of our studies with the earthworm Eisenia foetida suggest otherwise. This organism is extremely susceptible to the toxic action of many common pesticides and other chemicals, and there is good evidence that this species is among the more hardy of all the earthworms. Although many facets of the terrestrial ecosystem must be addressed with regard to chemical hazards, practicality dictates that emphasis be directed toward specific organisms representing a given segment of the terrestrial population. This article discusses the vital role of earthworms in the environment and why they are particularly useful as test organisms, and summarizes chemical toxicity data obtained in laboratory and field investigations.
Structure-activity relationships for nitrogen-containing aromatic molecules
Authors: Schultz T. Wayne , Moulton Becky A.
Published: March 2010

Twenty-four nitrogen-containing aromatic molecules, mono- and dicyclic homologs from each of 12 different analog sets, were studied to determine their relative acute static toxicities, monitored as population growth impairment to the ciliate Tetrahymena pyriformis. Quantitative structure-activity correlations between the molecular descriptors log l-octanol/water partition coefficient (log Kow) and log toxicity are reported. Using the complete data set the descriptor does not provide an adequate model for predictability. A scatter plot of log Kow versus log toxicity suggests two parallel linear correlations: one consisting of the more complex multiple H-polar nitrogen-containing compounds and the other with the single H-polar and in-ring substituted nitrogen-containing compounds.
Pentachlorophenol toxicity to amphipods and fathead minnows at different test pH values
Authors: Spehar R. L. , Nelson H. P. , Swanson M. J. , Renoos J. W.
Published: March 2010

Juvenile amphipods (Gammarus pseudolimnaeus and Crangonyx pseudogracilis) and fathead minnows (Pimephales promelas) were exposed to pentachlorophenol (PCP) at pH values of 6.5, 7.5, 8.0 and 8.5 for 96 h, and early life stages of fathead minnows were exposed for 32 d at the same pH values to determine the relationship between test pH and the acute and chronic toxicity of PCP. Residue analyses were performed on fathead minnows after 32 d to determine the relationship between test pH and PCP bioaccumulation. Technical-grade PCP (88% active ingredient; Dowicide EC7) was used as the toxicant source.

Acute exposures with all three species showed that PCP toxicity was decreased with increased test pH. The slopes of this relationship were similar for the amphipods, but were different from that observed for fathead minnows. Early life stage exposures of fathead minnows showed that chronic PCP toxicity and bioaccumulation were similarly decreased when pH values were increased. The decrease in chronic PCP toxicity appeared to be due to the reduction in PCP accumulation as a direct result of the increased ionization of PCP at higher pH values, indicating that the ionized form was less toxic per unit concentration than was the un-ionized form. However, these studies suggest that chronic as well as acute toxicity may be caused by both forms of PCP when significant concentrations are present in solution.
Impact of atrazine and hexachlorobiphenyl on the structure and function of model stream ecosystems
Authors: Lynch Thomas R. , Johnson Howard E. , Adams William J.
Published: March 2010

Six laboratory model streams derived directly from natural stream communities were used to study the effects of atrazine and a hexachlorobiphenyl isomer on community structure and function. Two streams were treated with 2,4,5,2′,4′,5′-hexachlorobiphenyl (0.10 μ/L) dissolved in acetone, two streams received atrazine (25 μg/L) dissolved in dimethylsulfoxide and each of the two remaining streams received one of the carrier solvents at the same solvent concentration as the solute-treated streams (0.69 μl/L). The chemicals were administered to the streams for four 30-d periods, each of which was followed by a 60-d recovery period.

The results indicate that at the concentrations used, neither chemical had any significant or lasting effects on the structure of macroinvertebrate populations, periphyton standing biomass or rates of primary production and community respiration. The negative nature of the results for hexachlorobiphenyl are of special interest because in these experiments all components of the biota accumulated substantial quantities of this chemical.

Macroinvertebrate drift in the streams increased abruptly upon the injection of both solutes and their carrier solvents. This response appeared to be a reaction primarily to the solvents rather than the solutes. This effect should be investigated in more detail as it indicates that carrier solvents may alter the outcome and interpretation of test results.