bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation and impact of phthalate plasticizers on soil microbial communities
Authors: Cartwright Colin D , Thompson Ian P , Burns Richard G 
Published: March 2010

Abstract
To assess the impact of phthalateson soil microorganismsand to supplement the environmental risk assessment for these xenobiotics, soil was treated with diethyl phthalate (DEP) or di (2-ethyl hexyl) phthalate (DEHP) at 0.1 to 100 mg/g. Bioavailability and membrane disruption were proposed as the characteristics responsible for the observed fate and toxicity of both compounds. Diethyl phthalate was biodegraded rapidly in soil with a half-life (t50 deg) of 0.75 d at 20°C, and was not expected to persist in the environment. The DEHP, although biodegradable in aqueous solution (t50deg &lt; 15 d at 20°C), was recalcitrant in soil, because of poor bioavailability (only 10% degraded by 70 d at 20°C) and was predicted to account for the majority of phthalate contamination in the environment. Addition of DEP or DEHP to soil at a concentration similar to that detected in nonindustrial environments (0.1 mg/g) had no impact on the structural diversity (bacterial numbers, fatty acid methyl ester analysis) or functional diversity (BIOLOG) of the microbial community. At concentrations representative of a phthalate spill, DEP (&gt;1 mg/g) reduced numbers of both total culturable bacteria (by 47%) and pseudomonads (by 62%) within 1 d. This was due to disruption of membrane fluidity by the lipophilic phthalate, a mechanism not previously attributed to phthalates. However, DEHP had no effect on the microbial community or membrane fluidity, even at 100 mg/g, and was predicted to have no impact on microbial communities in the environment.
Toxicity of tri-n-butyltin to sea urchin eggs and larvae: Relation to bioaccumulation at the nanomolar level
Authors: Girard Jean-Pierre , Szpunar Joanna , Pedrotti Maria-Luiza , Pesando Danielle 
Published: March 2010

Abstract
Nnomolar concentrations of tri- n-butyltin (TBT) from 5 × 10−10 M to 5 × 10−9 M, were assayed on sea urchin (Paracentrotus lividus) egg cleavage and on larval development. Preincubation enhanced TBT toxicity to first cleavage DNA and protein syntheses but not to intracellular calcium sequestration. Exposure to nanomolar TBT affected the larval development up to the ninth day by reducing arm length and increasing the diameter of the rudiment. Chromatographic analysis of TBT in eggs shows a dose-dependent biomagnification with a half-time of 5 min, which is much shorter than the length of preincubation necessary to provoke cytotoxicity at the same concentration (5 × 10−9 or 5 × 10−10 M). Our data suggest that nanomolar concentrations of TBT similar to those encountered in polluted waters could directly affect sea urchin egg development after fertilization and the larval cycle, these effects being independent of bioaccumulation.
Assessing the potential toxicity of resuspended sediment
Authors: Bonnet Corinne , Babut Marc , Férard Jean-François , Martel Louis , Garric Jeanne 
Published: March 2010

AbstractTwo moderately contaminated freshwater sediments (Sorel Harbour, St. Lawrence River, Canada) were subjected to a suspension event. The objective was to assess the environmental impact of the disposal of dredged material in water, in particular, the short-term effects of dumping on the water column and the long-term effects of dredged sediment deposits. In a series of microcosms, the sediments were left to stand for 25 d under flow-through conditions (reference conditions). In a second series of microcosms, sediments were vigorously suspended for 15 min before being left to settle and were submitted to the same treatment as reference sediments during the following 25 d. Physicochemical and biological parameters (Daphnia magna and Hydra attenuata survival) were measured in overlying water throughout the experiment. Sediment toxicity was assessed with Chironomus tentans and Hyalella azteca exposed to sediments collected at both the beginning and end of the 25-d period. Pore-water toxicity was evaluated with D. magna. During the suspension process, in the Sorel Harbour mixed sediment overlying water, we observed effects on H. attenuata survival and ammonia and metals (chromium, copper, and zinc) releases. Meanwhile, in reference (nonmixed) and mixed sediments as well as in associated pore waters, there were no significant chemical modifications nor biological effects after the 25-d experiments. The developed approach, which attempts to simulate a dumping process, aims at allowing the assessment of the short- and long-term hazards resulting from a resuspension process in overlying water and in resettled sediments using both chemical and biological measurements.
Metabolism of fluoranthene in different plant cell cultures and intact plants
Authors: Kolb Marit , Harms Hans 
Published: March 2010

Abstract
The metabolism of fluoranthene was investigated in 11 cell cultures of different plant species using a [14C]-labeled standard. Most species metabolized less than 5% of fluoranthene to soluble metabolites and formed less than 5% nonextractable residues during the standardized 48-h test procedure. Higher metabolic rates were observed in lettuce (Lactuca sativa, 6%), wheat (Tricitum aestivum, 9%), and tomato (Lycopersicon esculentum, 15%). A special high metabolic rate of nearly 50% was determined for the rose species Paul's Scarlet. Chromatographic analysis of metabolites extracted from aseptically grown tomato plants proved that the metabolites detected in the cell cultures were also formed in the intact plants. Metabolites produced in tomato and rose cells from [14C]-fluoranthene were conjugated with glucose, glucuronic acid, and other cell components. After acid hydrolyses, the main metabolite of both species was 1-hydroxyfluoranthene as identified by gas chromatography–mass spectrometry and high-performance liquid chromatography with diode array detection. The second metabolite formed by both species was 8-hydroxy-fluoranthene. A third metabolite in tomatoes was 3-hydroxyfluoranthene.
Monitoring wading bird exposure to agricultural chemicals using serum cholinesterase activity
Authors: Parsons Katharine C , Matz Angela C , Hooper Michael J , Pokras Mark A 
Published: March 2010

Abstract
Oganophosphorus (OP) and carbamate (CB) insecticidesare widely used and havea variety of lethal and sublethal effects on nontarget wildlife, primarily through cholinesterase (ChE) inhibition. To assess possible exposure to anti-ChE compounds in wading birds, we monitored breeding colonies in northeast U.S. estuaries (Boston Harbor, MA; New York Harbor, NY; Nantucket Sound, MA; Delaware Bay, DE; and Rehoboth Bay, DE) from 1991 to 1996. We documented serum ChE activities in black-crowned night-heron (Nycticorax nyticorax), cattle egret (Bubulcus ibis), snowy egret (Egretta thula), little blue heron (E. caerulea), and glossy ibis (Plegadis falcinellus), and we investigated factors known to affect ChE, including age, nutritional and immune status, location of the colony (estuary), and exposure to ChE-inhibiting compounds. Exposure to anti-ChE compounds in all species was supported by at least one of the following: positive pyridine-2-aldoxime methochloride (2-PAM; OP) and/or spontaneous (CB) ChE reactivations, negative or nonsignificant age correlations in most species, or regional land-use patterns. We observed negative or nonsignificant relationships between ChE and age in most species. Only glossy ibis showed the age-related patterns of ChE activity observed in other altricial species. Of the remaining potential explanatory factors, location (estuary) but not nutritional or immune status was the only one having a significant relationship with ChE activity (p &lt; 0.024). Significant differences among colonies were consistent with surrounding land uses, specifically active agriculture. We conclude that extensive monitoring of serum ChE in wildlife can identify locations of exposure and provide reference data for wildlife pesticide-risk assessment.
Genotype and toxicity relationships amongHyalella azteca: II. Acute exposure to fluoranthene-contaminated sediment
Authors: Duan Yihao , Guttman Sheldon I , Oris James T , Huang Xiaodong , Burton G Allen 
Published: March 2010

AbstractThis study examined the genotypic responses of Hyalella azteca to the toxicity of sediment contaminated by the polycyclic aromatic hydrocarbon (PAH) fluoranthene. We monitored the time to death for 696 H. azteca exposed to ultraviolet light and sediment spiked with fluoranthene. The survival distribution functions within the genotypes at each of three variable allozyme loci (acid phosphatase [ACP*], glucose-6-phosphate isomerase [GPI*], and phosphoglucomutase [PGM*]) were compared using a log-rank test. Results showed significant differences among SDFs at all three loci. No association of heterozygosity with time to death was observed. The homozygote ACP*-CC was associated with decreased survivorship compared with ACP*-AA, ACP*-BB, and ACP*-AB. However, GPI*-AA was associated with increased survivorship compared with GPI*-BB, GPI*-CC, and GPI*-BC. Significant differences in resistance also were observed for PGM*-BB versus either PGM*-AC or PGM*-BC. These results indicate that differential resistance to PAH phototoxicity was genetically related, producing significant alteration in the frequencies of several genotypes in the population.
Characterizing aquatic ecological risks from pesticides using a diquat dibromide case study III. Ecological process models
Authors: Bartell Steven M , Campbell Kym Rouse , Lovelock Cynthia M , Nair Shyam K , Shaw Jennifer L 
Published: March 2010

Abstract
The purpose of this study was to add to the set of risk characterization approaches developed in an earlier study beyond simple comparisons of exposure and effects (e.g., quotients, overlapping frequency distributions) through use of ecological models. These models were used to evaluate the ecological risks from diquat dibromide for individual Daphnia using an individual-oriented model, a population of bluegill sunfish (Lepomis macrochirus) using a demographic model, and ecological communities within a generic lake in Central Florida, USA, using the Comprehensive Aquatic Systems Model. The ecological models presented in this study more realistically address the potential risks posed by pesticides to individual organisms, populations, communities, and ecosystems than risk assessment methods based on simple comparisons of exposure and effects. The ecological impacts calculated by these models support the inference of minimal risks being posed by diquat dibromide to aquatic systems as concluded from previous empirical comparisons of exposure and toxicity data.
Different sensitivity to organophosphates of acetylcholinesterase and butyrylcholinesterase from three-spined stickleback (Gasterosteus aculeatus): Application in biomonitoring
Authors: Sturm Armin , Wogram Jörn , Segner Helmut , Liess Mathias 
Published: March 2010

Abstract
Different cholinesterases from brain and body muscle of the fish three-spined stickleback (Gasterosteus aculeatus) were investigated concerning their potential use in the biomonitoring of organophosphate insecticides (OPs). Stickleback brain contained acetylcholinesterase (AChE) but no butyrylcholinesterase (BChE). Body muscle contained both AChE and BChE. In vitro, body muscle BChE was three orders of magnitude more sensitive than brain or body muscle AChE to the OPs paraoxon and dichlorvos. In 1998, cholinesterase activities were recorded in stickleback from eight streams differing in pesticide contamination. Automated on-site samplers that selectively collect water during runoff events were used to obtain water samples for pesticide analysis. The OP parathion was found in stream water sampled during runoff events in five cases. The variation of brain and body muscle AChE activity between streams was not related to water contamination by pesticides. Body muscle BChE was strongly decreased (&gt;85%) in stickleback collected at all streams with previous parathion contamination events. A significant decrease in BChE (78%) occurred also, however, at one stream where other pesticides but no OPs were found. Because stickleback AChE and BChE differed strongly in their in vitro sensitivity and their response in the field, these enzymes should be considered separately in studies with fish.
Relative importance of calcium and magnesium in hardness-based modification of copper toxicity
Authors: Welsh Paul G , Lipton Joshua , Chapman Gary A , Podrabsky Tracy L 
Published: March 2010

AbstractWe cause of the relationship between water hardness and the toxicity of many metals, total hardness is used as a model parameter to calculate ambient water quality criteria for copper and other metals. However, the relative contribution of the Ca and Mg components of total hardness as modifiers of metals toxicity is not considered in the water quality criteria. Acute Cu toxicity was measured in rainbow trout (Oncorhynchus mykiss) and chinook salmon (O. tshawytscha) swim-up fry in laboratory waters that were formulated to have similar total hardness and alkalinity but different Ca and Mg concentrations. Experiments were performed at nominal total hardness values of 40 and 90 mg/L (as CaCO3). In four paired toxicity tests, acute Cu toxicity was significantly lower, i.e., 96-h LC50s were higher, in laboratory waters containing proportionately more Ca (Ca:Mg molar ratios of 1.5–5.2) than in waters containing less Ca (Ca:Mg molar ratios of 0.2–0.8). The relative increase in the 96-h Cu LC50 at higher Ca concentrations, but similar total hardness concentrations, was between 28 and 86% when the low Ca treatment was similar to American Society for Testing and Materials laboratory water (Ca:Mg molar ratio = 0.7). Failure to account for differences in Ca when matching or adjusting for total hardness thus exerts an important influence on the prediction of metal toxicity. These differences must be addressed in water-effect ratio testing in which paired tests with laboratory and site waters are conducted.
Assimilation of cadmium, chromium, and zinc by the green musselPerna viridisand the clamRuditapes philippinarum
Authors: Chong Kit , Wang Wen-Xiong 
Published: March 2010

AbstractThe green mussel Perna viridis and the clam Ruditapes philippinarum have been frequently used as biomonitors of coastal contamination in subtropical and tropical waters, yet the physiological processes controlling metal uptake in these bivalves are unknown. Assimilation efficiency (AE) is an important physiological parameter quantifying metal bioavailability from ingested food. We determined the AEs of Cd, Cr, and Zn in these bivalves feeding on five species of phytoplankton and one natural seston. The influences of the cytoplasmic distribution of metals in the algal cells and the digestive physiology of bivalves on metal AEs were also examined. Among the three metals, Zn was generally assimilated at the highest efficiency, i.e., 21 to 36% in the mussels and 29 to 59% in the clams. Cr was the least assimilated metal, with AEs being 10 to 16% in the mussels and 11 to 24% in the clams. The AEs of Cd and Zn in the clams were 1.8 to 4.7 and 1.1 to 1.9 times higher, respectively, than the AEs in the mussels. Assimilation efficiencies of Cr were, however, comparable between the mussels and the clams. A positive significant relationship between the metal AE and the percent of metals in the algal cytoplasm was found only for Cd in the clams, suggesting that Cd fractionation in the algal cells influenced its assimilation. No significant relationship, however, was found for other metals in both bivalves. A significant relationship between Cr assimilation efficiency and gut passage time (GPT) was documented in the mussels, indicating a higher assimilation when Cr was retained longer in the gut. There was also significant correlation of metal AEs among the three metals, which were probably subjected to the same digestive pathway in the bivalves. Our study demonstrated that both the green mussels and the clams were able to accumulate metals from ingested food source, and food quality appeared to have different effects on metal assimilation in different bivalve species.
Influence of iron(III) and humic acid on the photodegradation of pentachlorophenol
Authors: Fukushima Masami , Tatsumi Kenji , Morimoto Kengo 
Published: March 2010

Abstract
In an aqueous solution at pH 3.0 or 5.0 that contained Fe(III) only or both Fe(III) and humic acid (HA), 20 to 40% of the pentachlorophenol (PCP) present was degraded by light irradiation (λ &gt; 370 nm, 8 h). The release of Cl− was also observed. Gas chromatography/mass spectrometry (GC/MS) studies showed that 2-hydroxy nonachlorodiphenyl ether (2HNCP) and octa-chlorodibenzo-p-dioxine (OCDD) are produced in the presence of Fe(III) only. These were formed by the dimerization of the reaction intermediates from PCP via radical coupling. In contrast, no 2HNCP and OCDD could be detected when both Fe(III) and HA were present. These results can be attributed to the reaction intermediates from PCP covalently binding with HA, which prevents dimerization between PCP-derived reaction intermediates.
An optimized microtiterplate assay to detect acetylcholinesterase activity in individual Chironomus riparius Meigen
Authors: Fisher Thomas C , Crane Mark , Callaghan Amanda 
Published: March 2010

Abstract
A sensitive microtiter plate assay to detect acetylcholinesterase activity in fourth-instar Chironomus riparius (Meigen) larvae was developed and optimized to allow the measurement of pesticide inhibition in individuals. Optimal conditions, including enzyme concentration, pH, and substrate concentration, allow the sensitive measurement of changes in activity following exposure to the organophosphate insecticide chlorpyrifos. Significant reductions in activity were observed at pesticide doses of 0.05, 0.1, 1.0, and 5 mg/L following a 48-h exposure.
Evidence of oxidative stress in bluegill sunfish (Lepomis macrochirus) liver microsomes simultaneously exposed to solar ultraviolet radiation and anthracene
Authors: Choi Jonghoon , Oris James T 
Published: March 2010

Abstract
Many polycyclic aromatic hydrocarbons (PAHs) are acutely toxic to fish and other aquatic organisms in the presence of environmentally realistic intensities of solar ultraviolet radiation (SUVR). However, the biochemical mechanism of this toxicity is not well established. In this study, increased levels of both reactive oxygen species production and lipid peroxidation were hypothesized as a toxic mechanism. To test this hypothesis, the production of superoxide anion and of a lipid peroxidation product (malondialdehyde) was measured in bluegill sunfish (Lepomis machrochirus) liver microsomes. These microsomes were exposed to a representative phototoxic PAH (anthracene [ANT]) and to SUVR and normal laboratory fluorescent light (FLU) in four different combinations: FLU + no ANT, FLU + ANT, SUVR + no ANT, and SUVR + ANT. The highest mean levels of both superoxide anion and malondialdehyde production were observed in the SUVR + ANT group, and these levels were significantly different (p &lt; 0.05) from those in all other treatment groups. We conclude that the photoinduced toxicity of ANT, and possibly of other phototoxic PAHs, manifests at least in part through lipid peroxidation after increased production of reactive oxygen species.
Metal accumulation byCeratitis capitata(Diptera) and transfer to the parasitic waspCoptera occidentalis(Hymenoptera)
Authors: Kazimírová Mária , Ortel Johanna 
Published: March 2010

AbstractAccumulation of lead (Pb), cadmium (Cd), and copper (Cu) (from food) by the fruit fly (Ceratitis capitata Wiedemann; Diptera, Tephritidae) and the transfer of the metals to the internal solitary pupal parasitoid Coptera occidentalis Muesebeck (Hymenoptera, Proctotrupoidea, Diapriidae) were investigated experimentally by exposing host larvae to contaminated diets. Each metal was added to the diet at two concentrations: Cd, 50 and 100 μg/g; Pb and Cu, 400 and 800 μg/g diet dry weight. Whole-body concentrations of the applied metals and of zinc (Zn) in the host and parasitoid were determined by atomic absorption photospectrometry. Concentration factors (CFs) for all metals (based on initial dietary concentrations) were lower at the higher food contamination level. Cadmium (CF = 3.2–7.05) and Zn (CF = 2.79–7.05) were accumulated by fruit fly larvae more efficiently than were Pb (CF = 0.95–1.02) and Cu (CF = 0.35–0.78, except control: 37.2). Considerable quantities of the metals taken up by host larvae and retained in their pupae were eliminated via the meconium after eclosion of flies (Cd, 33%; Pb, 33–51%; Cu 24–39% of pupal metal burdens). Low proportions of the host metal content were transferred to the parasitoid (0.4–5.6% and 0.3–1.4% to pupae and adults, respectively, depending on the applied metal). The remaining amounts of the metals were detected in the host puparia that remained after wasp eclosion. Vitality and fecundity of the parasitoid were not impaired by host metal contamination. Thus, the parasitic wasp probably possesses an efficient regulatory mechanism that mediates excretion of toxic metals before pupation and that diminishes the potential hazard of high metal loads in the host.
Seasonal variation in radiocesium levels of largemouth bass (Micropterus salmoides): Implications for humans and sensitive wildlife species
Authors: Peles John D , Philippi Tom , Smith Michael H , Brisbin I Lehr , Gibbons J Whitfield 
Published: March 2010

AbstractTo examine seasonal variation in levels of radiocesium (137Cs) within largemouth bass (Micropterus salmoides; N = 589), fish were collected monthly over a one-year period from an abandoned reactor cooling reservoir. Month of collection, sex, age, and body mass (log transformed) were all significant factors influencing 137Cs concentrations. Levels of 137Cs reached a peak in late winter/early spring (February/March), and minimum values occurred in the fall (October). An asymmetric sawtooth model with a four-month period of increase and an eight-month period of decrease fit the data for monthly 137Cs values significantly better than symmetric sinusoidal and sawtooth models. The mean concentration of 137Cs for bass collected during all months was 7.09 Bq/g wet mass. All individuals examined, regardless of month, sex, age, or body mass, had 137Cs levels (2.95–12.60 Bq/g) that were much higher than the maximum level (0.60 Bq/g wet mass) generally considered safe for human consumption. Radiocesium is relatively long-lived within this reservoir and will continue to remain an important issue in risk assessments for both humans and wildlife species.