bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of taste repellents with northern bobwhites for deterring ingestion of granular pesticides
Authors: Mastrota F Nicholas , Mench Joy A.
Published: March 2010

The risk of accidental poisoning of birds may be reduced by adding an aversive tasting chemical to granular pesticides The efficacy of eight taste repellents in deterring consumption was therefore evaluated in a game species, the northern bobwhite (Colinus virginianus) Avoidance was measured using a two-cup preference test in which treated feeds were paired with untreated feeds in one experiment, and against other treated feeds in another experiment All repellents tested were significantly avoided without evidence of habituation during the 5 d test period The most effective repellents were d pulegone and quinine hydrochloride Methyl anthranilate, 2-heptanone, and lithium chloride also performed reasonably well, whereas sucrose octaacetate and cinnamaldehyde performed relatively poorly The d-pulegone was further evaluated using a one cup test with treated clay granules The effects of adding d-pulegone and/or a red dye (erythrosine) were evaluated with a two way factorial design Addition of d-pulegone strongly reduced consumption of granules (p< 0 001), whereas addition of erythrosine had no significant effect when added alone or in combination with d-pulegone Our results indicate that treating pesticide granules with a potent taste repellent, such as d-pulegone, is a promising approach to reduce the risk of their ingestion by birds
Evaluation of the robustness of the fathead minnow, Pimephales promelas, larval survival and growth test, U.S. EPA method 1000.0
Authors: Pickering Quentin H. , Lazorchak James M.
Published: March 2010

An intralaboratory study was conducted to evaluate the robustness of the Fathead Minnow (Pimephales promelas) Larval Survival and Growth Test, Method 1000.0. Toxicity tests were conducted with the reference toxicants hexavalent chromium (Cr6+) and copper (Cu), and the data were statistically analyzed using hypothesis testing. Differences in age, size, feeding regimes, and water quality did not cause more than a twofold difference in 13 subchronic values (SCVs) for Cr6+. These tests involved side-by-side tests initiated with 1-, 4-, and 7-d larvae or initiated with 1-d larvae and two size groups of 4-d larvae fed differently. The mean SCV was 3,600 μg Cr6+/L, and the values ranged from 2,100 to 4,200 μg Cr6+/L. Eleven of these tests with a homogeneous variance gave an average minimum significant difference (MSD) of 14.3%. The no-observed-effect concentration (NOEC) for growth was always lower than the effect on survival. In the side-by-side tests with 1-, 4-, and 7-d larvae exposed in hard water the SCV was 35 μg Cu/L for each age group. Except for one test with Cu in soft water, the effects of Cr6+ and Cu on growth were more sensitive than the effect on survival. These toxicity tests along with some nontoxicant studies indicated that reasonable differences in methods parameters did not cause any changes greater than a factor or two in analytical results despite the “noise” of biological variability.
The association of DNA damage to concentrations of mercury and radiocesium in largemouth bass
Authors: Sugg Derrick W , Chesser Ronald K , Brooks Janet A , Grasman Brian T
Published: March 2010

Largemouth bass from five lakes were examined to determine levels of contamination by mercury and radiocesium and amounts of DNA damage Concentrations of these toxicants and an index of body condition were regressed against over all DNA damage and DNA damage in individual tissues (liver, gills, and red blood cells) as indicated by the alkaline unwinding method Sample sites showed considerable heterogeneity in concentrations of mercury and radiocesium, as well as numbers of DNA strand breaks Generally, increased concentrations of toxicants were related to increased DNA damage Tissues may have responded to contaminants in different manners, red blood cells generally showed the greatest DNA damage while liver tissue showed the least Although body condition was related to DNA damage, it is unclear whether it has a direct effect or whether it is a correlated response to contamination by mercury and radiocesium The potential for repair of DNA strand breaks and cell turnover rates may play an important role in determining the ultimate amount of DNA damage in contaminated organisms
Inhibition of renal xenobiotic excretion by tetrachloroguaiacol: Mechanism and possible consequences
Authors: Oikari A. O. J. , Walden R. , Pritchard J. B.
Published: March 2010

The weak acid tetrachloroguaiacol (teCG; pKa 6.0) is the major chlorinated phenol produced during chlorine bleaching of wood pulp. Upon its release into the environment, it is persistent and markedly bioaccumulated (100- to 1,000-fold). Within the organism (pH ∼ 7.4), it should be >95% ionized, making it a likely inhibitor of renal organic anion transport. Its effects on both passive membrane permeability and mediated transport processes were determined in basolateral (BLM) and luminal membrane (BBM) vesicles isolated from the rat kidney cortex. Vesicular solute uptake was measured by the rapid filtration technique at pH 7.5. Passive membrane permeability (assessed by mannitol uptake) was altered only at very high concentrations of teCG (≥ 1,000 μM). In contrast, transport of the model organic anion p-aminohippurate (PAH) by BLM vesicles was significantly inhibited by as little as 5 μM (1.3 mg/L) teCG and totally abolished by 200 μM. Inhibition was competitive (K1 = 31.3 μM). Decreasing assay pH diminished inhibition of the PAH uptake, reflecting the reduced concentration of ionized teCG. Other membrane effects were seen at higher teCG concentrations (> 100 μM). The BLM sodium/glutarate cotransport was modestly, but significantly, stimulated by 100 to 500 μM teCG, whereas BBM sodium/glucose cotransport was inhibited by similar teCG concentrations. Thus, teCG has multiple effects on renal membrane function. However, at environmental levels (0.1 to 30 μM in plasma), its principal membrane effects would be related to changes in organic anion secretion.
Rapid mineralization of the herbicide atrazine in alluvial sediments and enrichment cultures
Authors: Topp Edward , Gutzman Donald W. , Millette Jacques , Gamble Donald S. , Bourgoin Bernard
Published: March 2010

The fate of atrazine in sediment sampled from two agricultural watersheds in the Great Lakes basin of southern Ontario was studied in laboratory flask incubations of sediment slurry and enrichment cultures. Atrazine at an initial concentration of 10 mg/L disappeared within 15 d in sediment slurries incubated aerobically at 30°C. Because atrazine concentrations were stable in similarly incubated autoclaved slurry and the lag preceding atrazine degradation was abolished by repeated atrazine additions, it was concluded that the herbicide was biodegraded. Rapid atrazine degradation was found in concentrated suspended particulates and surface (0 to 10 cm) sediments, but not in sediments taken from a depth of 20 cm. Atrazine was not degraded under anaerobic or denitrifying conditions. Sediment and enrichment cultures converted [U-ring-14C]-labeled atrazine to hydrophilic metabolites, tentatively identified as cyanuric acid and urea, and then to carbon dioxide.
Behavior of [14C]-4-nitrophenol and [14C]-3,4-dichloroaniline in laboratory sediment-water systems: Part 2. Desorption experiments and identification of sorptive fraction
Authors: Heim Kerstin , Schuphan Ingolf , Schmidt Burkhard
Published: March 2010

Both [14C]-4-nitrophenol (4-NP) and [14C]-3,4-dichloroaniline (3,4-DCA) were applied to laboratory sediment-water systems; these were a sandy sediment (SED-M), and a sediment with high clay/silt and organic carbon content (SED-J). After sorption periods of 2 d (assay I) and 28 d (assay II) the water phases were replaced by fresh sample water. About 20/10% (3.9/3.9% of total applied 4-NP in SED-M/SED-J) and 40/15% (8.5/6.2%; 3,4-DCA) of the sediment-associated radioactivity were initially (1 d of incubation) desorbed in assay I. The corresponding data of assay II amounted to 2/1% (0.9/0.7%; 4-NP) and 3/2% (1.7/1.4%; 3,4-DCA). No parent compounds were detected in the fresh-water phases. The radioactivity released in assay I was readsorbed to the respective sediment. Remobilization distinctly reflected the preceding sorption process, and that regarding sediment properties and chemical features of 3,4-DCA and 4-NP. Fractionation of the nonextractable residues of 3,4-DCA in SED-J revealed that the xenobiotic was mainly attached to the insoluble humin fraction (55.8/53.8% after 7/28 d of incubation). Only minor amounts were associated with fulvic (14.3/12.7%) and humic acids (5.3/6.1%). Experiments using a clay fraction of SED-J (< 0.063 μm; SED-J-C) and bentonite (CM) demonstrated that 3,4-DCA was primarily bound to the organic matter of SED-J-C. Concerning sorption of 3,4-DCA, both SED-J and SED-J-C behaved very alike; in contrast, CM showed a strikingly different pattern. Regarding “outdoor” situations, it may be concluded that 4-NP is not translocated very far from the site of contamination, whereas 3,4-DCA shows considerable mobility.
A novel detection scheme for herbicidal residues
Authors: Hannan Patrick J.
Published: March 2010

It is relatively simple to determine the growth rate of a microorganism culture, minute-by-minute, by monitoring the CO2 content of an air stream that has passed through the culture at a constant rate. Any change in the growth rate caused by the addition of a toxicant is readily detectable. This is the basis of a procedure for detecting sulfonylurea herbicides on vegetation. A freshwater alga (Chlorella pyrenoidosa sorokiniana) and baker's yeast (Saccharomyces cerevisiae) were the test organisms evaluated in this study. The alga was the more sensitive to sulfonylureas, and the effect of 0.01 μg of a sulfonylurea that had been simply leached from an apple leaf was evident in 15 min. Triazine herbicides inhibit the Chlorella even more rapidly than the sulfonylureas.
Integrity of a cellulose granular pesticide carrier in house sparrow gizzards
Authors: Best Louis B. , Gionfriddo James P.
Published: March 2010

This study evaluated the integrity of a cellulose-complex granular pesticide carrier in gizzards of house sparrows (Passer domesticus). Within 1 h after dosing, nearly all cellulose-complex granules had disappeared from the birds' gizzards. Cellulose granules remained intact for 14 d, however, in a hydrochloric acid solution without the mechanical grinding of the gizzard.
Alteration of the homing-flight in the honey beeApis melliferaL. Exposed to sublethal dose of deltamethrin
Authors: van dame Rémy , Meled Maggy , Colin Marc-Edouard , Belzunces Luc P.
Published: March 2010

Foraging activity of bees is currently disturbed by treatments with pyrethroid agrochemicals. To discover eventual troubles of spatial orientation of the foragers, we exposed bees to sublethal doses of deltamethrin sufficiently low to avoid motor incoordination or muscular troubles. In an insect-proof tunnel, bees were trained to forage at a feeder 8 m from their nucleus. When temperature and global radiance conditions were optimal, some foragers were caught, exposed to a deltamethrin dose 27 times lower than its LD50, and released after 20 min of recovering. Among the contaminated bees, 54% took flight toward the sun and 81% did not come back to their nest within 30 s (which is 3 times longer than the mean time of control bees). Because pyrethroids are known to disturb learning and memory, we cannot conclude if this disorientation is due either to a trouble of information storage (wrong spatial perception or phototropism increase), or to a trouble of information retrieval (bad comparison of actual and memorized patterns). Routine chemical analysis of exposed bees does not detect residues of deltamethrin 3 h after bee sublethal exposure, although bees evidenced alteration in the flight.
Development of toxic equivalency factors for PCB congeners and the assessment of TCDD and PCB mixtures in rainbow trout
Authors: Newsted John L. , Jones Paul D. , Giesy John P. , Crawford Robert A. , Ankley Gerald T. , Tillitt Donald E. , Gooch Jay W. , Denison Michael S.
Published: March 2010

This study was undertaken to evaluate the relationship between mammalian and piscine 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency factors (TEFs) for PCBs, based on induction of CYP1A enzyme activity, catalytic protein, and mRNA. Rainbow trout administered a single i.p. injection of TCDD had an average (±SD) ED50 of 0.91 ± 0.14 μg TCDD/kg for induction of ethoxyresorufin O-deethylase (EROD) activity. Ortho-substituted PCB congeners 2,3,3′,4,4′-pentachlorobiphenyl (PCB 105), 2,3′,4,4′,5-pentachlorobiphenyl (PCB 118), 2,3,3′4,4′5-hexachlorobiphenyl (PCB !56), and 2,2′3,4,4′,5-hexachlorobiphenyl (PCB 138) did not induce CYP1A activity in rainbow trout. Only three non-ortho-substituted PCBs, i.e., 3,3′4,4′-tetrachlorobiphenyl (PCB 77), 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), and 3,3′4,4′5,5′-hexachlorobiphenyl (PCB 169) induced CYP1A enzyme activity, protein, and mRNA. The ED50s for induction of EROD activity were calculated as 134, 5.82, and 93.7 μg/kg for PCB 77, PCB 126, and PCB 169, respectively. The TCDD-TEFs based on EROD activity were 0.0006, 0.0014, and 0.0003 for PCB 77, PCB 126, and PCB 169, respectively. Binary mixtures of TCDD and three PCBs were also evaluated. Based on EROD activity and CYP1A protein, mixtures of TCDD and PCB 77 were slightly greater than additive. Mixtures of TCDD-PCB 156 and TCDD-PCB 126 were slightly less than additive. Results from these studies indicate that mammal-derived TEFs will underestimate the potency of planar chlorinated hydrocarbon mixtures to induce the CYP1A catalytic activity in rainbow trout. Also, while interactions among PCB congeners and TCDD were somewhat equivocal, they did not greatly differ from predicted additive responses.
Effects of carbaryl grasshopper control on nesting killdeer in North Dakota
Authors: Fair Jeanne M. , Kennedy Patricia L. , McEwen Lowell C.
Published: March 2010

There is currently special concern for the effects of range grasshopper control on insectivorous grassland birds, such as upland shorebirds. The direct and indirect effects on killdeer (Charadrius vociferus) of carbaryl applications for grasshopper control were investigated in North Dakota in 1992. Specimens were collected from two rangeland sites aerially sprayed with 1.44 and 1.12 kg/ha of Sevin-4-Oil (0.56 and 0.45 kg/ha carbaryl active ingredient, respectively) and two untreated areas. Potential exposure to carbaryl, estimated from pesticide residue concentrations of whole-body and gizzard contents, was highest 2 d after treatment and then decreased over time. Whole-body carbaryl residues averaged significantly higher (p < 0.05) in specimens from sprayed areas, particularly from sites where the higher carbaryl application was used. There was no difference in the mean brain AChE activity and whole-body lipid content of killdeer from treated and untreated areas. The relative abundance of arthropods (principal prey of killdeer) was also estimated on the treatment area. As expected, grasshopper densities declined significantly posttreatment but the spray caused a temporary increase in the availability of affected grasshoppers. The two application rates caused similar reductions in grasshopper numbers. Killdeer did not exhibit a functional response of a prey switch as a result of the spray, but they did demonstrate an increased arthropod capture rate for a short period (8 d) after treatment. Although exposure was documented on the higher application rate area, this exposure was apparently not high enough to cause an impact on the parameters we measured in this study. These results support the conclusions of other studies that carbaryl, applied at the rate of 1.12 kg/ha, has little impact on birds and is equally as effective in reducing grasshopper numbers as the higher application rate.
An approach to quantifying spatial components of exposure for ecological risk assessment
Authors: Clifford Philip A. , Ludwig David F. , Barchers Daniel E. , Klingensmith J. Scott , Graham Richard V. , Sielken Robert L. , Banton Marcy I.
Published: March 2010

Estimating ecological risks associated with contaminants in the environment requires accurate characterization of the exposure of organisms to potentially toxic materials. Because organisms integrate contaminant exposure over space and time, estimating exposure concentrations reflective of actual exposures is a complex task. Quantification of spatial components of environmental exposure can utilize computerized Geographic Information Systems (GIS) as a central tool. The GIS was used to evaluate ecological risks to terrestrial receptors at a National Priorities List (NPL) site where dieldrin was one of the contaminants. The GIS was applied directly to estimating spatially weighted exposure concentrations within organisms' foraging, or exposure ranges. Moreover, GIS was also used for comparing exposure concentrations to “benchmark” concentrations and subsequent presentation of the results in a three-dimensional “risk surface” format. The three-dimensional risk surfaces were then superimposed on site-specific maps to serve as effective visual representations of site-specific quantified ecological risks and, as such, provide an effective risk-management decision-making tool. As an integral part of this approach, GIS serves as an interactive tool for assessing the effectiveness of proposed remedial alternatives by facilitating evaluation of effects of various remediation scenarios. This capability can be used to optimize remedial costs, benefits, and impacts.
A comparison of standard acute toxicity tests with rapid-screening toxicity tests
Authors: Toussaint Margaret W. , Shedd Tommy R. , van der Schalie William H. , Leather Gerald R.
Published: March 2010

This study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing: a freshwater rotifer (Branchionus calyciflorus); brine shrimp (Artemia salina); lettuce (Lactuca sativa); and two microbial tests (Photobacterium phosphoreum–Microtoxr̀ test, and a mixture of bacterial species–the Polytoxr̀ test). Standard acute toxicity test species included water fleas (Daphnia magna and Ceriodaphnia dubia), green algae (Selenastrum capricornutum), fathead minnows (Pimephales promelas), and mysid shrimp (Mysidopsis bahia). Sensitivity comparisons between rapid and standard acute toxicity tests were based on LC50/EC50 data from 11 test chemicals. Individually, the lettuce and rotifer tests ranked most similar in sensitivity to the standard tests, while Microtox fell just outside the range of sensitivities represented by the group of standard acute toxicity tests. The brine shrimp and Polytox tests were one or more orders of magnitude different from the standard acute toxicity tests for most compounds. The lettuce, rotifer, and Microtox tests could be used as a battery for preliminary toxicity screening of chemicals. Further evaluation of complex “real-world” environmental samples is recommended.
A proposal for the definition of resource equivalency factors for use in product life-cycle assessment
Authors: Guinée Jeroen B. , Heijungs Reinout
Published: March 2010

Environmental life-cycle assessment (LCA) of products has been the focus of growing attention in the last few years. The methodological framework has been developed rapidly, and a provisional “Code of Practice” has been drawn up by an international group of experts. One of the elements of LCA is impact assessment, which includes a characterization step in which the contributions of resource extraction and polluting emissions to impact categories such as resource depletion, global warming, and acidification are quantified and aggregated as far as possible. This can be achieved by multiplying extractions and emissions by a so-called equivalency factor and aggregating the results in one or more effect score(s) per impact category. In this report a proposal is developed for equivalency factors indicating the relative depletion of a resource per unit extracted. It is proposed to measure depletion by physical data on reserves and production and regeneration rates, and to distinguish between abiotic and biotic resources. Equations are developed to calculate equivalency factors for these two categories of resources, resulting in so-called abiotic depletion potentials (ADP) and biotic depletion potentials (BDP). The application of these ADPs and BDPs in LCA is illustrated.
Kinetics of phthalate ester biodegradation by Chlorella pyrenoidosa
Authors: Yan Hai , Ye Changming , Yin Chengqing
Published: March 2010

Experimental results show that Chlorella pyrenoidosa has an ability to accumulate and biodegrade phthalate esters. Bioconcentration factors of dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBF) reached their maxima of 162 at 24 h, 205 at 12 h, and 4,077 at 12 h. The average biodegradation rates of DMP, DEP, and DBF per day were found to be 13.4 mg/L, 7.3 mg/L, and 2.1 mg/L, respectively. Based on the experimental data, a second-order kinetic equation was formulated as - dC/dt = KNr, with a factor r indicating the rate of algal growth. Calculation of this equation fits well with the observed data, and the standard deviations between calculated and observed values were 1.72 mg/L, 1.80 mg/L, and 0.26 mg/L for DMP, DEP, and DBF, respectively.
Dehalogenation of chlorinated dioxins by an anaerobic microbial consortium from sediment
Authors: Beurskens Jacobus E.M. , De Wolf Johan , Toussaint Erel , van der Steen Jan M.D. , Slot Pieter C. , Commandeur Laetitia C.M. , Parsons John R.
Published: March 2010

Anaerobic microorganisms enriched from Rhine River sediments are able to remove chlorine substituents from poly-chlorinated dibenzo-p-dioxines (PCDDs). A model PCDD, 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4–TeCDD) was reduc-tively dechlorinated to both 1,2,3–and l,2,4–trichlorodibenzo-/>-dioxins (1,2,3–and 1,2,4–TrCDD). These compounds were further dechlorinated to 1,3–and 2,3–dichlorodibenzo-p-dioxins and traces of 2–monochlorodibenzo-p-dioxin. This is the first report in the literature of the anaerobic microbial dechlorination of PCDDs. The same enrichment culture was previously found to deSchlorinate chlorinated benzenes (CBs) and polychlorinated biphenyls (PCBs). An anaerobic culture able to remove aryl chlorines from three classes of compounds has not been reported before. The rate at which the culture dechlorinates 1,2,3,4–TeCDD (t1/2 = 15.5 d) was between those observed for CBs and PCBs. This study shows that reductive dechlorination may have an effect on PCDDs in sediments, as has been demonstrated for CBs and PCBs. The formation of metabolites with a conserved 2,3-substitution pattern from 1,2,3,4–TeCDD indicates that dechlorination of highly chlorinated dibenzo-p-dioxins may result in metabolites that are potentially more toxic than the parent compounds.
Physiological and biochemical perturbations inDaphnia magnafollowing exposure to the model environmental estrogen diethylstilbestrol
Authors: Baldwin William S. , Milam David L. , Leblanc Gerald A.
Published: March 2010

The estrogenic properties of many environmental contaminants, such as DDE and PCBs, have been associated with reproductive failure in a variety of vertebrate species. While estrogens have been measured in many invertebrate species, the function of this hormone in invertebrates is controversial. The objective of the present study was to identify possible physiological and biochemical target sites for the estrogenic effects of some xenobiotics on the freshwater crustacean Daphnia magna using the model environmental estrogen diethylstilbestrol (DES). Chronic exposure of daphnids to 0.50 mg/L DBS reduced molting frequency among first-generation juveniles and decreased fecundity of second-generation daphnids. Adult first-generation daphnids chronically exposed to DES, as well as adult daphnids acutely exposed to DES for only 48 h, were examined for steroid hormone metabolic capabilities using testosterone as the model steroid. The rate of elimination of two major hydroxylated metabolites of testosterone was significantly reduced, and elimination of glucose conjugates of testosterone was significantly elevated from exposure to 0.50 mg/L DES. These results demonstrate that multigeneration exposure of daphnids to DES results in reduced fecundity and altered steroid metabolic capabilities. Thus, some arthropods, like vertebrates, are sensitive to the effects of endocrine-disrupting chemicals.
The effects of dieldrin on the sperm ultrastructure of the earthworm Eudrilus eugeniae (oligochaeta)
Authors: Reinecke Sophiè A. , Reinecke Adriaan J. , Froneman Moya L.
Published: March 2010

Earthworms of the species Eudrilus eugeniae were exposed to dieldrin, using the contact filter paper method, to study the sublethal effects of the pesticide, which is still widely used in many parts of Africa, on the ultrastructure of spermatozoa. The concentrations ranged from 0.154 to 1.54 μg/cm2 and exposures lasted 48 h. The spermathecae were dissected out and prepared for electron microscopy. Dieldrin was extracted from the worms by steam distillation and analysed by ECD-gas chro-matography. A description of the sperm ultrastructure is presented. This study showed that dieldrin at relatively low concentrations caused structural damage, especially to the nucleus of the sperm. It is argued that this finding could contribute toward the development of a model for predicting environmental quality, based on sperm morphology, sperm motility, and sperm density. The sublethal effects of dieldrin on sperm morphology could provide a subanimal test for ecotoxicity since its effects will most probably be manifested at the population level.
Behavioral effects of pre- and postnatal exposure to individual polychlorinated biphenyl congeners in rats
Authors: Holene Edel , Nafstad Inger , Skaare Janneche Utne , Bernhoft Aksel , Engen Pat , Sagvolden Terje
Published: March 2010

Rats were exposed in utero and through mother's milk either to the coplanar PCB congener 3,3′,4,4′,5–CB (IUPAC no. 126) or to the mono-ortho-substituted PCB congener 2,3′,4,4′,5–CB (IUPAC no. 118). The different groups of mothers were exposed to 1 and 5 mg/kg body weight of PCB 118, and 2 μg/kg b.w. of PCB 126 every second day from day 10 to day 20 of gestation. The exposure did not affect the body weight of the dams or the size, weight, sex ratio, or physical development of the offspring. Operant behavioral testing revealed that the PCB-exposed offspring showed both poorer visual discrimination and higher activity level than did the controls. The coplanar PCB 126 congener was the most potent treatment. These results show that both PCB 118 and PCB 126 produced significant neurotoxic effects in the offspring of exposed females in absence of clinical maternotoxic and fetotoxic effects.
Aqueous sample preparation for bioassay using supercritical fluid extraction
Authors: Wolfe Martha F. , Hinton David E. , Seiber James N.
Published: March 2010

Supercritical fluid extraction (SFE) has become a valuable tool in the preparation of environmental samples for analysis. Most applications to date have been to extract compounds from solid matrices for later analysis by gas chromatographic or high-performance liquid chromatographic methods. The objective of this research was to extend SFE applications to aqueous samples extracted on EmporeTM (C18) solid-phase extraction disks. This technique, which essentially eliminated the use of conventional solvents in preparing the filtered samples, yielded extracts that were compatible with bioassay. The method included aqueous sample extraction onto C18 Empore disks and subsequent elution with supercritical CO2 to isolate and concentrate analytes of interest, using glass beads as an off-line trapping matrix. Analytes were then redissolved in reconstituted water and evaluated for toxicity using the larval medaka, Oryzias latipes, 96-h static toxicity bioassay. Tests with water spikes of molinate, thiobencarb, methyl parathion, and malathion extracted on disks and eluted by SFE gave quantitative recoveries (>90%). Samples of a mixture of these compounds prepared using SFE produced an LC50 of 2.88 mg/L, compared with an LC50 of 2.60 mg/L produced by a water sample directly spiked with equivalent concentrations. Extracts of rice-field water prepared for bioassay and gas chromatographic analysis using the SFE method gave good recoveries without loss of biological activity.
Contaminant exposure and biochemical effects in outmigrant juvenile chinook salmon from urban and nonurban estuaries of puget sound, Washington
Authors: Stein John E. , Hom Tom , Collier Tracy K. , Brown Donald W. , Varanasi Usha
Published: March 2010

Juvenile chinook salmon (Oncorhynchus tshawytscha) were sampled in Puget Sound, Washington, for 2 consecutive years from contaminated urban estuaries, a nonurban estuary, and from the respective hatcheries to assess exposure to anthropogenic chemicals and to determine if biochemical changes were occurring as a consequence of exposure. Exposure to polycyclic aromatic hydrocarbons (PAHs), chlorinated hydrocarbons, and butyltins was determined. The mean concentrations of PAHs and PCBs in stomach contents and PCBs in liver were significantly higher in salmon from the urban estuaries compared to fish from the nonurban estuary in both sampling years. Higher hepatic concentrations of PCBs than DDTs were found in fish from the urban estuaries, but butyltins were rarely detected. Further, mean concentrations of fluorescent aromatic compounds in bile, an estimate of exposure to PAHs, and hepatic cytochrome P4501A and levels of hepatic DNA adducts were also significantly higher in salmon from the urban estuaries compared to either the nonurban estuary or the hatcheries. Results demonstrated increased exposure to chemical contaminants in outmigrant juvenile salmon during their relatively brief residence in urban estuaries of Puget Sound. Moreover, the exposure was sufficient to elicit biochemical responses, which suggest a potential for other biological effects to ensue.
Taxonomic level sufficient for assessing pollution impacts on the southern california bight macrobenthos—revisited
Authors: Ferraro Steven P. , Cole Faith A.
Published: March 2010

Taxonomic sufficiency is the pragmatic concept of identifying organisms only to the taxonomic level necessary and sufficient to meet a study's objectives. Sufficient taxonomy was determined for detecting differences in macrobenthic taxa richness, a dominance index, and three diversity indices between a reference and two pollution-impacted stations in the Southern California Bight using a wide variety of sampling protocols. A higher taxonomic level was deemed sufficient for a given measure and sampling protocol if the statistical power of t tests performed on data grouped to it was essentially the same as that when tests were performed on data grouped to all lower taxa. The sufficient taxon for the optimum sampling protocol was phylum except when assessing biological stimulation based on differences in mean log10(number of taxa) where it was species. Generic dominance and diversity indices were sufficient independent of the sample units tested (0.02, 0.06, and 0.1 m2) and sample size (n ≥ 2). We recommend family level identification of specimens collected using the optimum sampling protocol when assessing macrobenthic community impacts in the study area because familial analyses are very likely to be sufficient. Confounding effects of sampling variables need to be accounted for when determining the true cost efficiency of and the underlying reason(s) for the sufficiency of higher taxonomy.
Relative potency of polychlorinated dibenzo-p-dioxins and dibenzofurans for inducing mixed-function oxygenase activity in rainbow trout
Authors: Parrott Joanne L. , Dixon D. George , Hodson Peter V. , Servos Mark R. , Huestis Usan L.
Published: March 2010

Toxic equivalent factors (TEFs) were generated for various polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) to compare the relative potencies as inducers of liver mixed-function oxygenase (MFO) activity in rainbow trout (Oncorhynchus mykiss). Trout, dosed orally with one of five PCDD congeners, either [3H]-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), l,2,3,7,8-pentachlorodibenzo-p-dioxin (PnCDD), 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (1,2,3,6,7,8-HxCDD), or [14C]-1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (1,2,3,4,7,8-HxCDD), or [14C]-1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) or one of four PCDF congeners, either 2,3,7,8-tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-pentachlo-rodibenzofuran (1,2,3,7,8-PnCDF), 2,3,4,7,8-pentachlorodibenzo furan (2,3,4,7,8-PnCDF), or 1,2,3,4,7,8-hexachlorodibenzofuran (HxCDF), showed increases in liver ethoxyresorufin O-deethylase (EROD) activity up to 250-fold. Liver concentrations of congeners were better predictors of EROD activity than oral dose. TEFs, ratios of the potency of each congener to that of TCDD, were calculated comparing “threshold” PCDD concentrations that induced EROD significantly above control levels. In cases of nonparallel dose-response curves between congeners, these comparisons are more relevant to environmental situations as PCDDs are compared at concentrations closer to those in the environment, instead of at higher pharmaceutical levels. Threshold-based TEFs were: PnCDD, 1.8; 1,2,3,6,7,8-HxCDD and 1,2,3,4,7,8-HxCDD, 0.4; HpCDD, 0.05; 2,3,4,7,8-PnCDF, 2; TCDF, 0.5; 1,2,3,7,8-PnCDF and HxCDF, 0.4. The ranking of potencies of the PCDFs was the same in fish as in mammalian tests, with the exception of PnCDD and 2,3,4,7,8-PnCDF, which were more potent to fish than was TCDD. Fish TEFs calculated at the threshold of EROD induction were about four to five times larger than international TEFs (I-TEFs), which are based on mammalian tests. At low concentrations typical of environmental exposures, TEFs may be different from mammalian-based TEFs.
Lesions and parasites in white suckers, Catostomus commersoni, in bleached-kraft pulp mill-contaminated and reference rivers
Authors: Couillard Catherine M. , Gagnon Pierre , Hodson Peter V. , Dodson Julian J.
Published: March 2010

The objective of this study was to determine if the prevalences of lesions and parasites were different in white suckers (Catostomus commersoni) living upstream and downstream from a bleached-kraft pulp mill in the St. Maurice River, Quebec, Canada. Fish were sampled from two downstream and one upstream sites and were examined internally and externally. Fish living downstream from the mill had more abundant visceral fat, a higher prevalence of deformed fin rays, and a higher prevalence of black livers than fish caught upstream. They were also more frequently infested by intestinal parasites and less frequently infested by larvae of the nematode Eustrongylides in the mesentery. These changes could not be associated specifically to exposure to the pulp mill effluent since they were either explained by among-site differences in fish length or by an upstream-downstream ecological gradient other than the effluent gradient. This ecological gradient was demonstrated by comparison with a reference river, the Gatineau, that had similar physical characteristics but no pulp mill.
Toxicity and hazard ranking of s-triazine herbicides using microtox® two green algal species and a marine crustacean
Authors: Gaggi C. , Duccini M. , Bacci E. , Sbrilli G. , Bucci M. , Naby A.M. Hasab El
Published: March 2010

The acute toxicities of five s-triazines (atrazine, prometryn, simetryn, ametryn, terbutryn) were measured using two algae (one freshwater species, Selenastrum capricornutum, and one marine species, Dunaliella tertiolecta), Microtoxr̀ bacteria, and the brine shrimp, Artemia salma. The algae were one to three orders of magnitude more susceptible to tested compounds than were bacteria or brine shrimp. The transformation of effective concentrations of the chemicals, obtained from toxicity measurements, into percent of the saturation level in water is proposed as a first evaluation of potential hazard to aquatic systems. Simetryn was found to be the most hazardous s-triazine for all species tested.
Do aquatic insects avoid cadmium-contaminated sediments?
Authors: Hare Landis , Shooner Frédéric
Published: March 2010

The long-term colonization of profundal lake sediments having a range of spiked cadmium (Cd) concentrations (0.007 to 2.7 μol/g dry wt.) was measured in the field. Population densities of two of the most abundant colonizing insects (the chironomids Procladius [Holotanypus] sp., and Sergentia coracina) were unrelated to the Cd gradient, even though both taxa accumulated Cd in direct relation to its concentration in sediment. Cadmium concentrations in these taxa ranged from approximately 0.3 to 5 μg/g, and 1 to 65 μg/g, respectively, along the sediment Cd gradient. Cadmium concentrations in Chironomus (salinarius gp.) sp. larvae also responded positively to the sediment Cd gradient and ranged from 0.2 to 50 μg/g. In contrast with the two other taxa, the abundance of Chironomus (salinarius gp.) sp. larvae was negatively correlated with the sediment Cd gradient. To determine if the abundance pattern of Chironomus (salinarius gp.) sp. was the result of a behavioral or a toxic response, larvae of the three chironomid taxa were given a choice between field]control and Cd-spiked sediments in the laboratory. None of the taxa avoided the Cd-spiked sediments, suggesting that the lower abundance of Chironomus (salinarius gp.) sp. at high Cd concentrations in the field was due to Cd toxicity and not to avoidance of the Cd-rich sediments.
The acute whole effluent toxicity of storm water from an international airport
Authors: Fisher Daniel J. , Turley Steven D. , Turley Bonnie S. , Yonkos Lance T. , Ziegler Gregory P. , Knott Melvin H.
Published: March 2010

In October 1990, the U.S. Environmental Protection Agency promulgated application requirements with deadlines for storm-water dischargers associated with industrial activity and certain municipal systems. Major airports have a number of hydrocarbon-based contaminants that could appear in storm-water runoff. In addition, ethylene, diethylene, and propylene glycol deicing and anti-icing mixtures are used during freezing and near-freezing weather. The objective of this study was to characterize the potential acute impact on aquatic life from industrial storm-water discharges from an international airport. Samples from winter storm events caused acute toxicity to both the fathead minnow (Pimephales promelas) and the daphnid (Daph-nia magna), with LC50 values for both species as low as 1.0 to 2.0% effluent. The toxicity of the samples was due to the various glycol-based deicer/anti-icer mixtures used during these events. High oxygen demands and elevated total nitrogen levels are other potential problems during anti-icing/deicing activities. Samples from rain events during the nonwinter months at the airport did not cause acute toxicity unless associated with fuel spills. As a result of this study, a new discharge permit has been issued for this airport, requiring the implementation of plans for the collection and recycling and/or disposal of the deicer/anti-icer mixtures.
A biomarker, P450 RGS, for assessing the induction potential of environmental samples
Authors: Anderson Jack W. , Rossi Steven S. , Tukey Robert H. , Vu Tien , Quattrochi Linda C.
Published: March 2010

In this study we describe the use of a transgenic cell line for the identification of potentially toxic compounds in test solutions and environmental samples. The reporter gene system (RGS), derived from a human liver cancer cell line, has been engineered such that the CYP1A1 gene, when activated by an inducer compound, will produce luciferase instead of P450. Eighteen hours after application of an inducer the reaction is stopped by rinsing, the cells lysed, and the cytoplasm measured for luminescence and protein content (for normalization). Induction by such compounds as dioxin, dioxin-like PCB congeners (co-planars), and polycyclic aromatic hydrocarbons (PAHs) infers these xenobiotics are present at levels that are potentially toxic, carcinogenic, or mutagenic to organisms. Multiple wells with attached cells in 2 ml of media were inoculated with various concentrations of toxicants in organic solvents (including DMSO, toluene, and dichloromethane). Volumes tested successfully thus far are 2 to 20 μl of solvent. Solvent extracts (using standard extraction methods) of aquatic sediments were directly applied to the assay system. Test results show significant RGS induction from concentrations of inducer compound that, if present in a typical 40-g sediment sample, would be (in ng/g or ppb): 0.05 for dioxin; 10 to 1,000 for a range of coplanar PCB congeners; about 2,000 for several Aroclor mixtures; and 300 for a mixture of PAHs. A mixture of pesticides at concentrations about four times the PAH levels did not produce an induction response. Results presented here indicate that testing for the presence of potentially toxic chemicals in environmental samples could be performed rapidly, with sensitivity and specificity using this RGS cell line.
Atmospheric deposition of pesticides in a small southern saskatchewan watershed
Authors: Waite Don T. , Sommerstad Hal , Grover Raj , Kerr Lorne A. , Westcott Neil D. , Irvine Don G.
Published: March 2010

Weekly atmospheric deposition samples were collected from early May to early September during 1984 to 1987 in a small agricultural watershed near Regina, Saskatchewan, an area in the midst of extensive agricultural pesticide use in the Canadian prairies. “Bulk” deposition samples were collected weekly in duplicate and analyzed for six herbicides (bromoxynil, 2,4–D, dicamba, diclofop, triallate, and trifluralin) and five insecticides (carbaryl, carbofuran, chlorpyrifos, deltamethrin, and dimethoate). In general, no significant differences were found among the duplicate samples. Over the 4-year period, the frequency of weekly detection of herbicides during the growing seasons was 0, 32, 39, 53, 58, and 67% for trifluralin, bromoxynil, triallate, diclofop, dicamba, and 2,4–D, respectively. For insecticides, only carbaryl and carbofuran were detected in one to two samples in the years for which the insecticides were analyzed. This infrequent detection reflected the relatively high detection limits set for the insecticides as compared to those for the herbicides. The seasonal herbicide atmospheric deposits during the growing period over the 4-year period (mg ha−1) ranged from 90 to 234 (bromoxynil), 386 to 1,374 (2,4-D), 20 to 219 (dicamba), 43 to 338 (diclofop), and 9 to 260 (triallate). Highest deposition rates were measured during and immediately following the spraying periods, with lesser, but significant, amounts also being detected during the harvest operations in August.
Recovery of known-age Hyalella azteca (amphipoda) from sediment toxicity tests
Authors: Tomasovic Michael J. , Dwyer F. James , Greer Ivan E. , Ingersoll Christopher G.
Published: March 2010

Recovery of 1-, 7-, 14-, or 21-d-old Hyalella azteca from sediment was evaluated. Recovery of 1- and 7-d-old amphipods was below an acceptability criterion of 80% survival for sediment tests. Another important aspect to consider when conducting sediment tests with H. azteca is defining mortality. A second study was conducted to evaluate the decomposition rate of dead amphipods in sediment. Regardless of sediment type, ≥ 90% of the amphipods started to break apart within 12 h of death; specifically, the head separates from the body. Therefore, if an immobile amphipod with its head and body intact is recovered in sieved material, it was probably alive within 12 h of the end of the test (an amphipod may be alive before sieving but may die during the sieving process). However, immobile amphipods removed from the sediment surface before sieving are known to be dead.
Distribution and excretion of Cd, Hg, methyl-Hg and Zn in the predatory beetle Pterostichus niger (coleoptera: Carabidae)
Authors: Lindqvist Lars , Block Mats , Tjälve Hans
Published: March 2010

Excretion and distribution of cadmium (Cd), mercury (Hg), methylmercury (methyl-Hg), and zinc (Zn) were studied in the predatory beetle, Pterostichus niger. Specimens of P. niger were fed with insect larvae containing 109Cd, 203Hg, methyl-203Hg, or 65Zn. After ingestion of the larvae, the metal contents in the beetles were measured daily for 30 d by γ-spectrometry. Additional beetles were used for autoradiography 5, 15, and 19 d after ingestion of the metals. Excretion of the metals was fast during an initial interval but occurred thereafter at a slow rate. After 2 weeks, the contents of Cd and inorganic Hg had decreased to approximately 1% of the ingested amounts. For Zn and methyl-Hg, higher levels were retained in the beetles. Thus, after 30 d, Zn content was 20% of the ingested amount, whereas for methyl-Hg 60% was retained in the body. Autoradiography showed high levels of all metals in the gut. For methyl-Hg, in contrast to inorganic Hg, there was also an evenly distributed labelling in most body tissues. This labelling was also seen for Zn, although at a lower level than for methyl-Hg. Cadmium showed a localisation in the integument, which was not seen for the other metals. Our results show that patterns of uptake and excretion of the examined metals in P. niger vary considerably and that the distribution pictures show specific features for the individual metals.
Toxicity testing with artificial streams: Effects of differences in current velocity
Authors: Lowell Richard B. , Culp Joseph M. , Wrona Frederick J.
Published: March 2010

When designing toxicity tests with lotic organisms, the role of current velocity is a key consideration when evaluating the test organism's response. We conducted a series of short-term toxicity experiments with the mayfly Baetis tricaudatus Dodds to determine the effect of current velocity on mayfly response to the reference toxicant sodium chloride. The tests were run at three substratum-level velocities: low (0 cm/s), medium (6 cm/s, typical of estimated intrasubstratum velocities in the field), and high (12 cm/s). The end points measured for the mayflies were immobilization and number of molts. The animals showed signs of stress, and the EC50 was lower in the 0 cm/s treatment, probably due to insufficient delivery of oxygen to the gills. This did not, however, lead to much change in sensitivity (measured as lowest-observed-effect concentration; LOEC) to the reference toxicant. Furthermore, neither EC50 nor LOEC differed between 6 and 12 cm/s. This suggests a threshold between 0 and 6 cm/s above which the effect of current velocity was no longer measurable. These results provide initial support for the recommendation that short-term toxicity tests using lotic organisms should ensure that the animals are exposed to at least some flow. Long-term tests, and those with different toxicants, may require further fine-tuning of current velocity.