bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of storage temperature and duration on toxicity of sediments assessed by Crassostrea gigas oyster embryo bioassay
Authors: Beiras Ricardo , His Edouard , Seaman Matthias N L 
Published: March 2010

Abstract
The effects of temperature and duration of storage on the toxicity of estuarine sediments were investigated with the Crassostrea gigas oyster embryo bioassay. Sediments ranging from unpolluted (controls) to extremely polluted with heavy metals (&gt;100 ppm Hg, Cu, Zn, and Pb) and total hydrocarbons (&gt;1,000 ppm) were collected from sites in southwest France and northern Spain. Control sediments were toxic only at the highest concentrations tested and after freezing in liquid nitrogen (−196°C). Polluted sediments significantly reduced the success of oyster embryogenesis. Analysis of variance showed that the effect of storage temperature on toxicity increased with the prolongation of storage. Prolonged storage of fresh (4°C) sediments resulted in a loss of toxicity, which was more rapid in the less-polluted sediments. Deep-frozen sediments (−196°C) were highly toxic regardless of origin and storage time, and because deep-freezing causes spurious toxicity in the control samples, it cannot be recommended for toxicological studies. In the context of the assessment of sediment toxicity by embryo–larval bioassays, fresh (4°C) storage is recommended when sediments need to be stored for no longer than a few days. The advisable duration of fresh storage to avoid false-negative results is directly related to the degree of toxicity. Should the sediments require prolonged storage, freezing at −20°C appears to be the best choice.
Relationship between reproduction, sediment type, and feeding activity ofLumbriculus variegatus(Müller): Implications for sediment toxicity testing
Authors: Leppänen Matti T , Kukkonen Jussi V.K 
Published: March 2010

AbstractThe impact of reproduction and its interaction with sediment type on feeding activity of Lumbriculus variegatus are important because one major pathway in bioaccumulation of hydrophobic sediment-associated contaminants takes place through ingested sediment. In this study, the surface egesting behavior and the reproduction of the oligochaete were studied to understand this relationship and to give recommendations for the use of L. variegatus in sediment toxicity testing. Single individuals were used as replicates allowing proper control of reproduction behavior and egestion rate. Reproduction, growth, and egestion rates were clearly different in the two fine-grained unpolluted lake sediments used in the first 28-d experiment. The feeding of oligochaetes stopped during the reproduction process in the second 30-d experiment. Individuals divided at their middle; the anterior part took 2 d and the posterior part took 6 to 7 d to regenerate new segments and to initiate egestion. Culture conditions determined at what size the animals were able to reproduce during the test. In our tests 9 mg wet weight was the approximate minimum organism size needed for reproduction behavior. Recommendations for sediment toxicity and bioaccumulation testing using L. variegatus include using the largest oligochaetes in culture if reproduction is the endpoint and using recently fragmented individuals with complete segments if animals are employed in bioaccumulation tests.
Heavy metals in bullfrog (Rana catesbeiana) tadpoles: Effects of depuration before analysis
Authors: Burger Joanna , Snodgrass Joel 
Published: March 2010

Abstract
Although tadpoles may well be excellent organisms to use as bioindicators of heavy metal contamination, the relationship of deposition in the body compared to the tail, and the effect of sediments or other debris in the digestive tract on heavy metal concentrations is unknown. We examined the effect of experimental depuration of bullfrog (Rana catesbeiana) tadpoles on heavy metal and selenium concentrations in intact tadpoles, as well as their bodies and tails. We defined depuration in this experiment as allowing defecation as an elimination process for intestinal contents (=clearing). We maintained wild-caught tadpoles in clean water for 0, 24, 48, and 72 h to determine the effects of clearing on heavy metal concentrations. We also examined the concentrations of heavy metals in the whole body and digestive tract separately. We test the null hypotheses that no differences occur in metals as a function of time in uncontaminated water, and that no differences occur in metal concentrations in the body compared to the tail and to the digestive tract. We rejected these hypotheses based on regression models. Variance in concentrations of chromium (77%) and lead (70%) were explained by part (body, tail, whole body) and clearing time; for manganese (80%), mercury (64%), selenium (28%), and cadmium (25%) the variation was explained only by body part; for arsenic (53%), the variation was explained by part, clearing time, and weight of the various parts. For those metals in which clearing time explained part of the variation, metal concentrations in both the body and tail decreased after 24 and 48 h, but increased slightly thereafter. Clearing, however, did not greatly decrease metal concentrations in either the body or tail. These data suggest that for some metals (mercury, manganese, cadmium, selenium), clearing has no effect, and for others the effect is slight. For fresh tadpoles, however, the digestive tract contained significantly higher concentrations of all metals than either the body or head, probably reflecting metals absorbed to sediment particles in the gut.
Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures
Authors: Besser John M , Ingersoll Christopher G , Leonard Edward N , Mount David R 
Published: March 2010

AbstractTechniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. We investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by ≥70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.
Subchronic and reproductive toxicity of emamectin benzoate to mallard ducks and northern bobwhite quail
Authors: O'Grodnick Joseph S , Wislocki Peter G , Keenan Kevin P , Beavers Joann B , Frey Larry T , Jaber Mark 
Published: March 2010

Abstract
Avian reproduction studies were performed in both the mallard and the northern bobwhite. Emamectin benzoate was incorporated into the diets of the two avian species prior to and during a period of reproduction. Mallards were exposed at dietary concentrations of 0, 4, 8, 20, or 40 ppm of emamectin benzoate for 20 weeks, whereas northern bobwhites were exposed to dietary concentrations of 0, 4, 13, 40, or 125 ppm of emamectin benzoate for 22 weeks. Birds were monitored for body weight, feed consumption, general health, and reproductive parameters. At the end of the reproduction period, all adult birds were examined for gross morphologic changes, and adult birds in the high-dose concentration groups were examined for neuropathologic effects. No treatment-related mortalities, overt signs of toxicity, or treatment-related effects on adult body weight or feed consumption occurred at any of the concentrations tested in either species. No treatment-related effects were observed upon any of the reproductive parameters measured. Emamectin benzoate did not induce gross or light microscopic lesions in the brain, spinal cord, or peripheral nerves to the level of the distal branches of the sciatic nerve, including the tibial nerve, in either the mallard or northern bobwhite. The no observed effect concentrations for mallards and northern bobwhites exposed to emamectin benzoate in the diet were 40 ppm and 125 ppm, respectively.
Toxicity of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin to early life stage brook trout (Salvelinus fontinalis) following parental dietary exposure
Authors: Johnson Rodney D , Tietge Joseph E , Jensen Kathleen M , Fernandez Joseph D , Linnum Ann L , Lothenbach Douglas B , Holcombe Gary W , Cook Philip M , Christ Suzanne A , Lattier David L , Gordon Denise A 
Published: March 2010

AbstractThe toxicity of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) to the early life stages of F1 generation brook trout (Salvelinus fontinalis) was determined, when dosed by maternal transfer. Effects were compared across six treatments, including a control. The experimental groups, based on TCDD concentrations in freshly spawned eggs (control, 41, 84, 156, 285, and 517 pg TCDD per gram egg [wet weight]), were established by treating 1.5-year-old brook trout with TCDD-dosed food throughout the period beginning with final gonadal maturation and continuing until just prior to spawning. Measurement endpoints assessed at various times throughout the study, included (1) TCDD and lipid concentrations in ovaries, eggs, alevins, and juvenile fish, (2) mortality, (3) fertility indices, (4) growth, (5) juvenile sex ratios, (6) pathology, and (7) cytochrome P4501A1 mRNA (CYPIA1) levels in embryos. The cumulative lethality dose response was determined just prior to hatch, at swim-up, and at the end of the study. The concentration in eggs causing 50% mortality (LCegg50) at swim-up and at the end of the study were 138 and 127 pg TCDD per gram egg, respectively. No treatment effects were observed on fertility, growth, or juvenile sex ratios. Pathologies were observed that have been previously reported in TCDD-exposed salmonid embryos, including edema in free embryos from all TCDD-exposed treatment groups at hatch. At the end of the test, juvenile fish from all treatments exhibited an increased prevalence of exophthalmia compared to the controls. The ECegg50 for this effect was 117 pg TCDD per gram egg. Histological analysis of the end-of-test juveniles, in gonad, nerve, vertebrae, neuromasts, liver, kidney, gut, gas bladder, skin, and blood vessels, did not indicate any significant pathology below the LCegg50. P4501A1 mRNA levels in whole 91-d postspawn free embryos from the 84 pg TCDD per gram egg treatment were 2.8 times higher compared with control or 41-pg TCDD per gram egg treatments. Results from this study were consistent with other published results of TCDD effects on salmonids, in which the exposures occurred after fertilization.
Evaluation of aquatic toxicity and bioaccumulation of C8- and C9-alkylphenol ethoxylates
Authors: Staples Charles A , Weeks John , Hall Jerry F , Naylor Carter G 
Published: March 2010

Abstract
The extensive database of acute and chronic aquatic toxicity data for alkylphenol ethoxylates (APEs) and selected biodegradation intermediates was reviewed and summarized for freshwater and saltwater aquatic microorganisms, algae, invertebrates, and fish inhabiting cold and warm water bodies. Most acute toxicity studies that tested APE-9 and APE-10, the most common commercially relevant APEs, reported results that ranged from about 1,000 to 10,000 μg/L. Results from studies testing alkylphenols, intermediate by-products of APE biodegradation, ranged from about 20 to 3,000 μg/L. Chronic values are a factor of about 2 to 10 lower. Although most studies used one of several common species and standard protocols to assay conventional endpoints, many nontraditional species and toxicological endpoints were also used. This toxicological database encompasses virtually all important types of aquatic habitats and classes of aquatic species. Bioaccumulation data from both laboratory and field studies indicate that alkylphenols have a low to moderate bioaccumulation potential. Fresh weight, nonlipid-based bioconcentration factors (BCFs) measured in the laboratory ranged from &lt; 1 to 1,250 for fish and 1 to 3,400 for invertebrates, whereas field bioaccumulation factors (BAFs) ranged from 6 to 487, with most values &lt; 100. Overall, these data provide an extensive and useful database to support environmental risk assessment activities.
Bioaccumulation and toxicity of silver compounds: A review
Authors: Ratte Hans Toni 
Published: March 2010

AbstractA eview of the literature revealed that bioaccumulation of silver in soil is rather low, even if the soil is amended with silver-containing sewage sludge. Plants grown on tailings of silver mines were found to have silver primarily in the root systems. In marine and freshwater systems, the highest reported bioconcentration factors (BCFs) were observed in algae (&gt;105), probably because of adsorption of the dissolved silver (&lt;0.45 μm fraction) to the cell surface. In herbivorous organisms (e.g., zooplankton and bivalves), the BCF was lower by about two orders of magnitude. Low amounts of silver were assimilated from food with no substantial biomagnification. In carnivores (e.g., fish), the BCF was also lower by one order of magnitude with no indication of biomagnification. Toxicity of silver occurs mainly in the aqueous phase and depends on the concentration of active, free Ag+ ions. Accordingly, many processes and water characteristics reduce silver toxicity by stopping the formation of free Ag+, binding Ag+, or preventing binding of Ag+ to the reactive surfaces of organisms. The solubility of a silver compound, and the presence of complexing agents (e.g., thiosulfate or chloride), dissolved organic carbon, and competing ions are important. In soil, sewage sludge, and sediments, in which silver sulfide predominates, the toxicity of silver, even at high total concentrations, is very low. The highly soluble silver thiosulfate complex has low toxicity, which can be attributed to the silver complexed by thiosulfate. Silver nitrate is one of the most toxic silver compounds. The toxic potential of silver chloride complexes in seawater is and will be an important issue for investigation. Aquatic chronic tests, long-term tests, and tests including sensitive life stages show lower toxicity thresholds (˜1 μg Ag+/L). The organisms viewed as most sensitive to silver are small aquatic invertebrates, particularly embryonic and larval stages.
Tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity tests
Authors: Kemble Nile E , Dwyer F James , Ingersoll Christopher G , Dawson Timothy D , Norberg-King Teresa J 
Published: March 2010

AbstractA method is described for preparing formulated sediments for use intoxicity testing. Ingredients used to prepare formulated sediments included commercially available silt, clay, sand, humic acid, dolomite, and α-cellulose (as a source of organic carbon). α-Cellulose was selected as the source of organic carbon because it is commercially available, consistent from batch to batch, and low in contaminant concentrations. The tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity testing was evaluated. Sediment exposures were conducted for 10 d with the amphipod Hyalella azteca, the midges Chironomus riparius and C. tentans, and the oligochaete Lumbriculus variegatus and for 28 d with H. azteca. Responses of organisms in formulated sediments was compared with a field-collected control sediment that has routinely been used to determine test acceptability. Tolerance of organisms to formulated sediments was evaluated by determining responses to varying levels of α-cellulose, to varying levels of grain size, to evaluation of different food types, or to evaluation of different sources of overlying water. In the 10-d exposures, survival of organisms exposed to the formulated sediments routinely met or exceeded the responses of test organisms exposed to the control sediment and routinely met test acceptability criteria required in standard methods. Growth of amphipods and oligochaetes in 10-d exposures with formulated sediment was often less than growth of organisms in the field-collected control sediment. Additional research is needed, using the method employed to prepare formulated sediment, to determine if conditioning formulated sediments before starting 10-d tests would improve the growth of amphipods. In the 28-d exposures, survival of H. azteca was low when reconstituted water was used as the source of overlying water. However, when well water was used as the source of overlying water in 28-d exposures, consistent responses of amphipods were observed in both formulated and control sediments.
Effects of repeated exposure to 4-nonylphenol on the zooplankton community in littoral enclosures
Authors: O'halloran Susan L , Liber Karsten , Gangl James A , Knuth Michael L 
Published: March 2010

AbstractThe effects of 4-nonylphenol (NP) on freshwater zooplankton were evaluated in 18 littoral enclosure mesocosms in northeastern Minnesota. The 18 enclosures were allocated to three blocks of six units with each block including two untreated control enclosures and one enclosure for each of four NP treatments (3, 30, 100, and 300 μg/L). Treated enclosures received 11 applications of NP over a 20-d period between July 8 and 28, 1993. Maximum NP concentrations measured in the water column 2 h after each application averaged (±SD) 5 ± 4, 23 ± 11, 76 ± 21, and 243 ± 41 μg/L over the 11 applications. Nonylphenol dissipated rapidly from the water column but was more persistent in sediments and in/on macrophytes. All cladoceran and copepod taxa were significantly reduced in abundance at 243 ± 41 μg/L; some sensitive taxa were also affected at 76 ± 21 and 23 ± 11 μg/L. While many rotifer taxa were unaffected at any of the test concentrations, several were affected at ≥76 ± 21 μg/L. Ostracods were only affected at 243 ± 41 μg/L. No zooplankton taxon was affected at 5 ± 4 μg/L. The period of maximum impact usually occurred within 1 to 7 d of the last NP application, and recovery to control abundance levels generally occurred within 7 to 28 d of the last NP application. Two sensitive taxa, Acroperus and Calanoida, did not recover at ≥76 ± 21 μg/L by the end of the study. The maximum acceptable toxicant concentration for protection of all zooplankton taxa was estimated at ˜10 μg/L, although overall community diversity was unaffected at 23 ± 11. The water was the most probable route of NP exposure, but the greater persistence of NP residues in/on macropyhtes may have contributed to the lack of recovery of some macrophyte-associated taxa.
Effects of 4-nonylphenol on benthic macroinvertebrates and insect emergence in littoral enclosures
Authors: Schmude Kurt L , Liber Karsten , Corry Timothy D , Stay Frank S 
Published: March 2010

AbstractThe effect of 4-nonylphenol (NP) on benthic, freshwater macroinvertebrates in littoral enclosures was evaluated over a 2-year period. Enclosures received 11 NP applications, 48 h apart, with nominal rates of 3, 30, 100, and 300 μg/L. Mean measured peak concentrations in integrated water column samples over the 20-d application period were 5 ± 4, 23 ± 11, 76 ± 21, and 243 ± 41 μg/L NP. Concentrations of NP in the water column decreased rapidly after the last application. Maximum NP concentrations measured in sediments, pore water, and macrophytes of a 300-μg/L enclosure were 27.4 mg/kg, 29.9 μg/L, and 89.6 mg/kg, respectively. The most abundant macroinvertebrate groups, Chironomidae, Oligochaeta, and Mollusca, decreased in abundance after application. Effects on Mollusca were the most severe. Their numbers were significantly reduced at the highest treatment (243 ± 41 μg/L NP) throughout most of the study. Oligochaetes (Naididae, Tubificidae) and chironomids (Tanytarsini, Chironomini) were also significantly reduced at the highest treatment, but populations recovered within 6 weeks. Snails and naidid oligochaetes were slightly affected at the second highest treatment (76 ± 21 μg/L NP). Insect emergence was reduced during and immediately postapplication, but the effects were likely caused or compounded by a surfactant sheen on the surface of the water that interfered with emergence and/or oviposition. The observed effects on the benthic community were most likely due to exposure from the water, although more persistent macrophyte-associated residues may have contributed to effects on Gastropoda, Naididae, and Tanytarsini. Macrophyte-associated NP residues may pose a small risk to benthic organisms, but it is probably minor compared to water exposures. The no-observed and lowest-observed-effect concentration for the benthic community was 23 ± 11 and 76 ± 21 mg/L NP, respectively.
Organochlorine contaminants and reproductive success of double-crested cormorants from Green Bay, Wisconsin, USA
Authors: Custer Thomas W , Custer Christine M , Hines Randy K , Gutreuter Steve , Stromborg Kenneth L , Allen P David , Melancon Mark J 
Published: March 2010

AbstractIn 1994 and 1995, nesting success of double-crested cormorants (Phalacrocorax auritus) was measured at Cat Island, in southern Green Bay, Lake Michigan, Wisconsin, USA. Sample eggs at pipping and unhatched eggs were collected and analyzed for organochlorines (including total polychlorinated biphenyls [PCBs] and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in embryos, and eggshell thickness. Of 1,570 eggs laid, 32% did not hatch and 0.4% had deformed embryos. Of 632 chicks monitored from hatching to 12 d of age, 9% were missing or found dead; no deformities were observed. The PCB concentrations in sample eggs from clutches with deformed embryos (mean = 10.2 μg/g wet weight) and dead embryos (11.4 μg/g) were not significantly higher than concentrations in sample eggs from nests where all eggs hatched (12.1 μg/g). A logistic regression of hatching success versus DDE, dieldrin, and PCB concentrations in sibling eggs identified DDE and not dieldrin or PCBs as a significant risk factor. A logistic regression of hatching success versus DDE and eggshell thickness implicated DDE and not eggshell thickness as a significant risk factor. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in double-crested cormorant eggs in Green Bay are still having an effect on reproduction in this species.