bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screening of environmental contaminants for ecdysteroid agonist and antagonist activity using the Drosophila melanogaster BII cell in vitro assay
Authors: Dinan Laurence , Bourne Pauline , Whiting Pensri , Dhadialla Tarlochan S , Hutchinson Thomas H 
Published: March 2010

Abstract
The BII bioassay was developed as a rapid and reliable tool for detecting potential insect growth regulators acting as ecdysteroid receptor (ant)agonists. Based on an ecdysteroid-responsive cell line from Drosophila melanogaster, this microplate assay is ideally suited to the evaluation of environmental contaminants as potential endocrine disrupters. Data are presented for about 80 potential environmental contaminants, including industrial chemicals, pesticides, Pharmaceuticals, phytoestrogens, and vertebrate steroids, and are compared with data for known (ant)agonists. Apart from androst-4-ene-3,17-dione (a weak antagonist), vertebrate steroids were inactive at concentrations up to 10−3 M. The vast majority of xenobiotics also showed no (ant)agonist activity. Among the industrial chemicals, antagonistic activity was observed for bisphenol A median effective concentration (EC50) of 1.0 × 10−4 M and diethylphthalate (EC50 of 2.0 × 10−3 M). Some organochlorine compounds also showed weak antagonistic activity, including o,p′-dichlorodiphenyldichloroethylene (DDE), p,p′-DDE, dieldrin, and lindane (EC50 of 3.0 × 10−5 M). For lindane, bisphenol A, and diethylphthalate, activity is not associated with impurities in the samples and, for lindane and bisphenol A at least, the compounds are able to compete with ecdysteroids for the ligand binding site on the receptor complex, albeit at concentrations very much higher than those found in the environment. The only pharmaceutical showing any detectable antagonist activity was 17α-ethynylestradiol. In the context of recent publications on potential endocrine disruption in marine and freshwater arthropods, these findings suggest that, for some compounds (e.g., diethylstilbestrol), ecdysteroid receptor-mediated responses are unlikely to be involved in producing chronic effects. The BII assay has a potentially valuable role to play in distinguishing between endocrine-mediated, which normally occur at submicromolar concentrations, and pharmacological effects in insects and crustaceans.
Zinc and cadmium body burdens in terrestrial oligochaetes: Use and significance in environmental risk assessment
Authors: Lock Koen , Janssen Colin R 
Published: March 2010

Abstract
Uptake and elimination kinetics of zinc and cadmium were studied in the oligochaetes Enchytraeus albidus and Eisenia fetida. Even at the highest exposure concentrations where E. fetida survived, the internal zinc concentration was still regulated to a constant level. Enchytraeus albidus could not regulate the internal zinc concentration as well, and the body burden increased after exposure to high zinc concentrations. After transfer to clean soil, the internal zinc concentration dropped back to the control level within a few weeks. For both species, internal cadmium concentrations did not reach equilibrium during the uptake experiments. The internal concentrations causing 50% reduction in cocoon production for E. fetida exposed to cadmium varied between different soil types, indicating that no fixed critical body burdens exist. For both zinc and cadmium, bioaccumulation factors decreased with increasing soil metal concentrations. Bioaccumulation factors may therefore be poor indicators of environmental risk. Their dependence on the total soil concentration makes bioaccumulation factors also unsuitable for assessing the influence of soil characteristics on the bioavailability of metals in contaminated field soils. For the same reason, uptake rate constants are probably not suited for this purpose.
Sediment geochemical controls on Cd, Cr, and Zn assimilation by the clam Ruditapes philippinarum
Authors: Fan Wenhong , Wang Wen-Xiong 
Published: March 2010

Abstract
Several important sediment geochemical factors (particle size, contact time, artificial sediment composition, acid volatile sulfide, and pure inorganic particles coated or uncoated with humic acid) were examined for their influences on the assimilation of Cd, Cr, and Zn in the marine clam Ruditapes philippinarum. Metal desorption and phase speciation were concurrently measured for these particles. Differences in particle size did not significantly affect metal assimilation. Increasing contact time with sediments decreased assimilation by the clams of Cr and Zn, but not of Cd. A significant positive relationship was found between the metal assimilation efficiency (AE) and the metal partitioning in the exchangeable fraction of sediments for Cd and Zn. The assimilation of metals was negatively dependent on the metal distribution in the reducible (Fe oxide) fraction, indicating that Fe oxide reduced metal bioavailability to the clams. Metal AEs measured with artificially prepared sediments were comparable to those measured with natural sediments. The AEs were significantly higher in artificial sediment without Fe oxide. Humic acid coating appeared to have no major and consistent influence on metal assimilation by the clams. The AEs measured for pure inorganic particles were much higher than those measured for sediments or artificially prepared sediments, except for the Fe oxide particles, indicating that digestion may behave differently for pure particles. Metals bound to artificially synthesized acid volatile sulfide were much less bioavailable to the clams. The AEs were as low as 4% for Cd and 7% for Zn, whereas the AE for Cr was somewhat similar to those measured for other types of particles. When all particle types (natural sediments, artificial sediment, and pure particles) were considered, a significant relationship was found between Cd AE and its desorption in seawater. This study has demonstrated that several geochemical fractions of the sediments, particularly the exchangeable, Fe oxide, and sulfide fractions, are important in determining metal bioavailability from sediments to clams.
Optimizing interpretation of in situ effects of riverine pollutants: Impact of upwelling and downwelling
Authors: Greenberg Marc S. , Burton G. Allen , Rowland Carolyn D. 
Published: March 2010

Abstract
In situ toxicity and bioaccumulation tests with Ceriodaphnia dubia (48 h), Chironomus tentans (96 h), Hyalella azteca (96 h), and Lumbriculus variegatus (96 h) were conducted at three stations on a river that was contaminated primarily with chlorobenzenes (CBs), and results were compared to a nearby reference site. Exposures were characterized by using minipiezometers for contaminant profiling and determination of hydraulic heads and vertical flow direction within the sediments and measuring contaminants in sediment, surface water, and exposure chamber water samples. Localized zones of upwelling and downwelling existed in the exposure areas at contaminated sites 5 and 18, while site 23 was downwelling at all measurement positions. Porewater samples from minipiezometers contained CBs at the three contaminated sites that were highest at site 23. However, sediment and water samples from exposure chambers at site 23 contained the lowest levels of CBs among the contaminated sites. The CBs were not detected at the reference site, but other organic contaminants and metals were detected at all sites, with the highest concentrations occurring at sites 5 and 18. In water column exposures, no significant (p &gt; 0.05) differences were observed in species survival between the contaminated sites and the reference. Mean percentage survival of H. azteca, C. dubia, and C. tentans exposed to surficial sediments (SS) at sites 5 and 18 was significantly (p &lt; 0.05) reduced compared to the reference, whereas only C. tentans survival was significantly reduced at site 23. Body residues of total CB congeners in L. variegatus exposed to SS were highest at site 18 (618 μmol/kg lipid) and lowest at site 23 (21 μmol/kg lipid). The data suggest that downwelling reduced the bioavailability of CBs in surficial sediments, most likely by mobilizing the freely dissolved and colloid-bound fractions to deeper sediments. Overall, downwelling conditions reduced the in situ exposure of organisms in surficial sediments and hence the toxicity and bioaccumulation of CBs. Hydrologic and chemistry data from nested minipiezometers improved the interpretation of exposure-effects relationships.
Vitamins A1 and A2 in hepatic tissue and subcellular fractions in mink feeding on fish-based diets and exposed to Aroclor 1242
Authors: Käkelä Anne , Käkelä Reijo , Hyvärinen Heikki , Asikainen Juha 
Published: March 2010

Abstract
Two-month-old female mink were fed diets based on either Baltic herring (Clupea harengus membras) or freshwater smelt (Osmerus eperlanus) for 21 weeks. A portion of the smelt-fed mink were exposed orally to polychlorinated biphenyls (PCBs), Aroclor 1242 (1 mg/d). Retinol (vitamin A1), 3,4-didehydroretinol (vitamin A2), and their different fatty acyl esters were studied in hepatic tissue, microsomes, and cytosol by argentated reversed-phase high-performance liquid chromatography. As a result of Aroclor exposure, concentrations of the fatty acyl esters of vitamins A1 and A2 were about one-tenth and those of unesterified A2 one-fourth those of the control levels. In the fatty acyl esters, percentages of stearates (A1-18:0 and A2-18:0) increased at the expense of the other fatty acyl esters. The Aroclor exposure decreased concentrations of alcoholic and esterified forms of the A2 analog more than those of the corresponding A1 analog. In microsomes, Aroclor decreased the alcoholic and esterified vitamin analogs to the same extent (to 9–17%). In the cytosol compared to the control, the concentrations of the vitamin esters fell below 10%, but the alcoholic analogs remained at 30 to 40%. Despite equal dietary supply, in mink fed on Baltic herring, the hepatic levels of vitamin A1 were only about one-third of the values found in the smelt-fed mink. The organochlorines also altered hepatic lipid composition and impaired breeding and kit growth. In the kits of the females fed on Baltic herring, blood hemoglobin was decreased.
Benzo[a]pyrene absorption and exposure pathways in the green mussel Perna viridis
Authors: Wang Wen-Xiong , Chow Alex T. S. 
Published: March 2010

Abstract
The absorption efficiency (AE) of benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon compound, in the green mussel Perna viridis was measured under different biological and food conditions (body size, food quantity, and food species). Uptake of BaP from the aqueous phase by different species of phytoplankton and green mussels was also experimentally quantified. A bioenergetic-based kinetic model was then used to separate the exposure pathways of BaP accumulation in the green mussels. Our results demonstrated that the AE of BaP in the green mussels ranged between 17 and 47%. Body size did not significantly affect the AE of BaP in the mussels. The AEs increased with a decrease in food availability, largely as a result of lengthening the gut passage of chemicals. The AEs differed by up to 2.3 times (17–39%) among the different food diets tested (four phytoplankton diets and one sediment diet). The BaP associated with the sediment was assimilated least efficiently. The difference in gut passage also appeared to account partially for the difference in AEs observed among different food types. No correlation between the AE and the distribution of BaP in the cytoplasm of phytoplankton cells was found. The concentration factor of BaP measured in four different marine phytoplankton species was in the range of 104 − 5 × 104 (L/kg). The calculated uptake rate constant of BaP in the green mussels was 6.37 L/g/d, and the efficiency of absorption of BaP from the aqueous phase was 6.6 to 8.8%. The model calculation indicated that under most circumstances, &gt;56% of BaP in mussels can indeed be derived from the uptake from the aqueous phase. However, the relative importance of aqueous and dietary exposure can be affected by the variation of AE, mussel's ingestion rate, and concentration of BaP in ingested food particles.
Effects of ethynylestradiol on the reproductive physiology in zebrafish (Danio rerio): Time dependency and reversibility
Authors: Van den Belt Kris , Wester Piet W. , van der Ven Leo T. M. , Verheyen Rudi , Witters Hilda 
Published: March 2010

Abstract
Environmental pollution with natural or synthetic estrogens may pose a serious threat to reproduction of wildlife species. This study describes the effects of 17-α-ethynylestradiol (EE2) on fish reproductive organs in a laboratory model. Adult zebrafish were semistatically exposed to nominal concentrations of 0, 10, and 25 ng/L EE2 for 24 d and then transferred to EE2-free medium. Gonadosomatic index (GSI), plasma vitellogenin concentration (VTG), and histology of the gonads (control and 10 ng/L only) were examined as a function of time. It was found that EE2 has an adverse impact on both male and female reproductive organs. Notably in females, gonadal changes were observed through histological evaluation after 3 d of exposure to 10 ng/L EE2, and this was followed by a reduction of GSI at day 6 of exposure. In males, a reduction of GSI and altered testis histology was found after 24 d of exposure to 10 ng/L. The observed effects on the ovary after EE2 exposure, combined with complete recovery after 24 d, is considered to be triggered by feedback at the level of the pituitary. In both males and females, VTG was induced in response to EE2 and normalized during the recovery period. The observed correlation between VTG and ovarian somatic index (OSI) demonstrates that excessive VTG induction may be predictive for adverse effects of EE2 on ovarian function in female zebrafish. These results indicate that long-term stimulation by synthetic estrogens such as EE2 might impair reproductive function in zebrafish in a reversible manner.
Postexposure feeding depression: A new toxicity endpoint for use in laboratory studies with Daphnia magna
Authors: McWilliam Ruth A. , Baird Donald J. 
Published: March 2010

Abstract
In situ bioassays with daphnids currently employ lethality as an endpoint, and although sublethal responses (reproduction and feeding rate) can be measured in the field, such endpoints pose major practical challenges. Previous studies have indicated that Daphnia magna exposed to toxic substances can exhibit delayed recovery in feeding behavior (postexposure feeding depression). This simple, robust response has the potential to be an ecologically relevant and potentially diagnostic endpoint. This study developed and tested the use of postexposure feeding depression as a toxicity endpoint in the laboratory environment. First, replicate numbers were manipulated to produce statistically reliable results. Second, postexposure feeding depression in D. magna was studied under laboratory conditions, by employing toxic substances with differing modes of action. Although most substances caused feeding inhibition during direct exposure, not all substances produced postexposure feeding depression. However, the use of lethality as a supplementary endpoint provided an alternative measure when no feeding depression was apparent after exposure. In combination, these endpoints offer a potentially more sensitive, ecologically relevant alternative to the use of lethality alone for in situ bioassay studies.
Relationship between lysosomal membrane destabilization and chemical body burden in eastern oysters (Crassostrea virginica) from Galveston Bay, Texas, USA
Authors: Hwang Hyun-Min , Wade Terry L. , Sericano Jose L. 
Published: March 2010

Abstract
Lysosomal destabilization was measured by using hemocytes of eastern oysters (Crassostrea virginica) collected along a chemical concentration gradient in Galveston Bay, Texas, USA. Results of the lysosomal response were compared to concentrations of organic compounds and trace elements in oyster tissue. Concentrations (on a dry-wt basis) ranged from 288 to 2,390 ng/g for polycyclic aromatic hydrocarbons (PAHs), 38 to 877 ng Sn/g for tri-n-butyltin (TBT), 60 to 562 ng/g for polyclorinated biphenyls (PCBs), and 7 to 71 ng/g for total DDT. Trace element concentrations (on a dry-wt basis) ranged from 1.1 to 4.0 μg/g for Cd, 105 to 229 μg/g for Cu, 212 to 868 μg/g for Al, and 1,200 to 8,180 μg/g for Zn. The percentage of destabilized lysosomes ranged from 34 to 81%. A significant positive correlation (p &lt; 0.05) was observed between lysosomal destabilization and body burden of organic compounds (PAHs, PCBs, TBT, and chlorinated pesticides). No significant correlation was found between metal concentrations and lysosomal destabilization. Based on lysosomal destabilization, the study sites in Galveston Bay can be placed in one of three groups: healthy (Hanna Reef and Confederate Bay), moderately damaged (Offats Bayou and Todd's Dump), and highly damaged (Yacht Club and Ship Channel). Lysosomal destabilization that is consistent with toxic chemical body burdens supports previous observations that lysosomal membranes are damaged by toxic chemicals and indicates that this method can serve as an early screening tool to assess overall ecosystem health by using oysters.
Concentrations of trace elements in eggs and blood of spectacled and common eiders on the Yukon-Kuskokwim Delta, Alaska, USA
Authors: Grand James B. , Franson J. Christian , Flint Paul L. , Petersen Margaret R. 
Published: March 2010

Abstract
We examined the relations among nesting success, egg viability, and blood and egg concentrations of As, Cd, Pb, Hg, and Se in a threatened population of spectacled eiders (Somateria fischeri) and a sympatric population of common eiders (S. mollissima) on the Yukon-Kuskokwim Delta, Alaska, USA, during 1995 and 1996. During the early breeding season, males and females had mean Se concentrations in their blood of 19.2 μg/g and 12.8 μg/g wet weight, respectively. Blood Se concentrations of females were correlated with egg concentrations. During brood rearing, blood Se levels were higher in adult females than in ducklings. Blood concentrations of Pb in spectacled eider females were higher than in common eider females captured at hatching, but blood concentrations of Se were similar. Trace element concentrations were not related to nest success or egg viability. We submit that nest success and egg viability of spectacled eiders are not related to concentrations of the trace elements we measured. Because blood Se concentrations declined rapidly through the breeding season and were not related to nest success or egg viability, we suggest that spectacled eiders are exposed to high concentrations of Se during winter that pose little threat to this population.
Altering cytochrome P4501A activity affects polycyclic aromatic hydrocarbon metabolism and toxicity in rainbow trout (Oncorhynchus mykiss)
Authors: Hawkins Stephanie A. , Billiard Sonya M. , Tabash Samir P. , Brown R. Stephen , Hodson Peter V. 
Published: March 2010

Abstract
The polycyclic aromatic hydrocarbons (PAHs) phenanthrene and retene (7-isopropyl-1-methyl phenanthrene) are lethal to rainbow trout (Oncorhynchus mykiss) larvae during chronic exposures. Phenanthrene is a low-toxicity, non-cytochrome P4501A (CYP1A)—inducing compound that accumulates in fish tissues during exposure to lethal concentrations in water. Retene is a higher toxicity CYP1A-inducing compound that is not detectable in tissue at lethal exposure concentrations. The metabolism, excretion, and toxicity of retene and phenanthrene were examined in juvenile and larval rainbow trout during coexposure to the model CYP1A inducer β-naphthoflavone (βNF), or to the inducer-inhibitor piperonyl butoxide to determine if modulating CYP1A activity affected PAH metabolism and toxicity. Phenanthrene metabolism, excretion rate, and toxicity increased with coexposure to βNF. Piperonyl butoxide inhibited phenanthrene metabolism and reduced the excretion of all phenanthrene metabolites. As a consequence, embryo mortality rates increased but rates of sublethal effects did not. Coexposure of trout to retene and βNF caused no change in retene metabolism and excretion, but retene toxicity increased, perhaps due to additivity. Piperonyl butoxide inhibited retene metabolism, decreased the excretion of some retene metabolites while increasing the excretion of others, and increased the toxicity of retene. These results support the role of CYP1A activity in PAH metabolism and excretion, and the role of the CYP1A-generated metabolites of PAHs in chronic toxicity to larval fish.
Monitoring of aromatic monosulfonic acids in coastal waters by ion-pair liquid chromatography followed by electrospray-mass spectrometric detection
Authors: Alonso M. Carmen , Pocurull Eva , Marcé Rosa Maria , Borrull Francisco , Barceló Damià 
Published: March 2010

Abstract
Spain is one of the European countries that still discharges untreated wastewaters and sewage sludge into the sea. Aromatic monosulfonated compounds were detected in 36 seawater samples collected bimonthly on the Catalonian coast (Spain) over a period of 18 months. These compounds are of environmental concern because of their limited biodegradability and high mobility within the aquatic system. A method based on a sequential solid-phase extraction procedure (SSPE) followed by ion-pair liquid chromatography coupled to electrospray ionization-mass spectrometry (IPC-ESI-MS) in negative ionization mode was used to monitor aromatic monosulfonated compounds in the Catalonian coastal waters. Triethylamine (TEA) and acetic acid (HOAc) were used as volatile mobile-phase additives. A comparison of two polymeric solid-phase extraction (SPE) materials for the extraction of 15 aromatic monosulfonated compounds of environmental concern was performed. The investigated adsorbents were the poly-styrene-divinylbenzene materials Lichrolut EN, from Merck, and Isolute ENV+, from International Sorbent Technology (IST). The influence of the matrix on the analysis of seawater samples was also studied. Applications of the developed analytical procedure to seawater samples gave limits of detection (n = 3) ranging from 0.6 to 45 pg on column for the target analytes. Barcelona and Tarragona locations were chosen along the Catalonian coast as sampling sites because of their large sewage discharges and intensive industrial activities. Samples were acquired from submarine outfalls of two rivers, Besos and Llobregat, located in the north and south of Barcelona city, respectively. Samples from petrochemical industry submarine outfalls located near the commercial port of Tarragona were also studied. Concentrations of benzenesulfonates (BS) and naphthalenesulfonates (NS) were of the order of ng/ml. Most of the collected samples were found to contain both isomers of mononaphthalenesulfonate. The study showed that these compounds can contaminate marine coastal waters.