bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of water quality and age on nickel toxicity to fathead minnows (Pimephales promelas)
Authors: Hoang Tham Chung , Tomasso Joseph R. , Klaine Stephen J. 
Published: March 2005

Abstract
This research characterized the effects of water quality and organism age on the toxicity of nickel (Ni)to fathead minnows (Pimephales promelas) to facilitate the accurate development of site-specific water-quality criteria. Nickel sulfate hexa-hydrate (NiSO4·6H2O) was used as the Ni source for performing acute toxicity tests (median lethal concentration after 96-h exposure [96-h LC50]) with &lt;1-d-old and 28-d-old P. promelas under varying regimes of hardness, pH, alkalinity, and natural organic matter (NOM). The toxicity of Ni was inversely related to water hardness between hardness values of 20 and 150 mg/L (as CaCO3). Below 30 mg/L alkalinity, Ni toxicity was related to alkalinity. The effect of pH was confounded by hardness and the presence of NOM. In the absence of NOM, the toxicity of Ni increased as pH increased at high hardness and alkalinity. In general, 28-d-old fish were less sensitive than &lt;1-d-old fish to Ni. This lower sensitivity ranged from 12-fold at low hardness and alkalinity (20 and 4 mg/L, respectively) to 5-fold at high hardness and alkalinity (100 and 400 mg/L, respectively). The presence of NOM (10 mg/L as dissolved organic carbon [DOC]) reduced Ni toxicity by up to 50%, but this effect appeared to be saturated above DOC at 5 mg/L. Incubating Ni with the NOM solution from 1 to 17 days had no effect on Ni toxicity. When using multivariate analysis, the 96-h LC50 for Ni was a function offish age, alkalinity, hardness, and NOM (96-h LC50 = −0.642 + 0.270(fish age) + 0.005(alkalinity) + 0.018(hardness) + 0.138(DOC)). When using this model, we found a strong relationship between measured and predicted 96-h LC50 values (r2 = 0.94) throughout the treatment water qualities. The biotic ligand model (BLM) did not accurately predict Ni toxicity at high or low levels of alkalinity. Results of our research suggest that the BLM could be improved by considering NiCO3 to be bioavailable.
Mercury accumulation and loss in mallard eggs
Authors: Heinz Gary H. , Hoffman David J. 
Published: March 2005

Abstract
Female mallards (Anas platyrhynchos) were fed diets containing 5, 10, or 20 ppm mercury as methylmercury chloride. One egg was collected from each bird before the start of the mercury diets and 15 eggs were collected from each bird while it was being fed mercury. The mercury diets were then replaced by uncontaminated diets, and each female was allowed to lay 29 more eggs. Mercury levels in eggs rose to about 7, 18, and 35 ppm wet-weight in females fed 5, 10, or 20 ppm mercury, respectively. Mercury levels fell to about 0.16, 0.80, and 1.7 ppm in the last egg laid by birds that had earlier been fed 5, 10, or 20 ppm mercury, respectively. Higher concentrations of mercury were found in egg albumen than in yolk, and between 95 and 100% of the mercury in the eggs was in the form of methylmercury.
Estrogenic potential of halogenated derivatives of nonylphenol ethoxylates and carboxylates
Authors: García-Reyero Natàlia , Requena Vanessa , Petrovic Mira , Fischer Birgit , Hansen Peter-Diedrich , Díaz Alfredo , Ventura Francesc , Barceló Damiá , Piña Benjamin 
Published: March 2005

Abstract
Hlogenated derivatives of nonylphenol and of its alkylates are generated during drinking water disinfection and treatment procedures. In this paper we analyze the potential of these compounds to interact with the estrogen receptor and to activate hormone-regulated gene promoters. We used the recombinant yeast assay (RYA) and the human breast cancer cell MCF7 proliferation assay for both estrogenic and antiestrogenic activities and the enzyme-linked receptor assay to examine in vitro binding to the receptor Many nonylphenol derivatives were very weak estrogens in our functional tests when compared to nonylphenol while retaining a substantial affinity for the estrogen receptor in vitro. Antiestrogenicity tests demonstrated that brominated nonylphenol and most of the carboxylated compounds studied here behaved as estrogenic antagonists in the RYA. We also detected an increased cytotoxicity for the carboxylated derivatives in both yeast and mammalian cells. We conclude that derivatization may mask the apparent estrogenicity of nonylphenol, but the resulting compounds still represent a potential hazard since they are still able to bind the estrogen receptor and to influence the physiological response to estrogens. Our results also illustrate the advantage of combining different methods to assay estrogenicity of unknown substances.
Importance of equilibration time in the partitioning and toxicity of zinc in spiked sediment bioassays
Authors: Lee Jung-Suk , Lee Byeong-Gweon , Luoma Samuel N. , Yoo Hoon 
Published: March 2005

Abstract
The influences of spiked Zn concentrations (1–40 μmol/g) and equilibration time (˜ 95 d) on the partitioning of Zn between pore water (PW) and sediment were evaluated with estuarine sediments containing two levels (5 and 15 μmol/g) of acid volatile sulfides (AVS). Their influence on Zn bioavailability was also evaluated by a parallel, 10-d amphipod (Leptocheirus plumulosus) mortality test at 5, 20, and 85 d of equilibration. During the equilibration, AVS increased (up to twofold) with spiked Zn concentration ([Zn]), whereas Zn-simultaneously extracted metals ([SEM]; Zn with AVS) remained relatively constant. Concentrations of Zn in PW decreased most rapidly during the initial 30 d and by 11- to 23-fold during the whole 95-d equilibration period. The apparent partitioning coefficient (Kpw, ratio of [Zn] in SEM to PW) increased by 10- to 20-fold with time and decreased with spiked [Zn] in sediments. The decrease of PW [Zn] could be explained by a combination of changes in AVS and redistribution of Zn into more insoluble phases as the sediment aged. Amphipod mortality decreased significantly with the equilibration time, consistent with decrease in dissolved [Zn]. The median lethal concentration (LC50) value (33 μM) in the second bioassay, conducted after 20 d of equilibration, was twofold the LC50 in the initial bioassay at 5 d of equilibration, probably because of the change of dissolved Zn speciation. Sediment bioassay protocols employing a short equilibration time and high spiked metal concentrations could accentuate partitioning of metals to the dissolved phase and shift the pathway for metal exposure toward the dissolved phase.
Chemometric modeling of main contamination sources in surface waters of Portugal
Authors: Tauler Romá , Lacorte Silvia , Guillamón Miriam , Cespedes Raquel , Viana Paula , Barceló Damia 
Published: March 2005

Abstract
Various chemometric data analysis methods, such as principal components analysis, multivariate curve resolution—alternating least squares, parallel factor analysis, and Tucker3, are proposed and compared for the resolution and modeling of main contamination sources in a large environmental data array obtained in an exhaustive environmental monitoring program that examined the quality of surface waters of Portugal. The study covered the analysis of 19 priority semivolatile organic compounds (SVOCs) frequently found in a total number of 644 surface water samples, including 46 different sites from throughout Portugal and corresponding to a period of 14 months, from April 1999 to May 2000. Main contamination sources of the analyzed SVOCs were identified and interpreted according to their chemical composition and according to their resolved geographical and temporal distribution profiles.
Fish full life-cycle testing for androgen methyltestosterone on medaka (Oryzias latipes)
Authors: Seki Masanori , Yokota Hirofumi , Matsubara Haruki , Maeda Masanobu , Tadokoro Hiroshi , Kobayashi Kunio 
Published: March 2005

Abstract
We studied the chronic effects of methyltestosterone (MT) on reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure to verify the applicability of the fish full life-cycle test (FFLC) for this androgen with this species. The exposure of parental (F0) medaka to MT was begun on embryos within 12 h postfertilization and continued for up to 101 d; assessment endpoints included embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to MT at each mean measured concentration of 0.35, 1.09, 3.29, 9.98, and 27.75 ng/L. Eggs (F1) spawned from the F0 fish at 98, 99, and 100 d posthatch were examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG level until 60 d posthatch. In the FFLC with medaka, MT induced masculinization of both secondary sex characteristics and gonads. We observed that all F0 fish in the 27.75-ng/L treatment group showed male secondary sex characteristics in which no fish with ovary could be discerned. Several fish with ovaries in F0 and F1 generations treated with 9.98 ng/L showed male secondary sex characteristics. We also observed swollen abdomens in the F0 and F1 female fish in the 9.98-ng/L treatment group. These swollen abdomens were induced by enlarged ovaries and were accompanied with declined fecundity and fertility in the F0 generation. These results indicate that MT reduces the reproductive potential of medaka and that the FFLC with this species is applicable to the evaluation of androgens.
Energy-based modeling as a basis for the analysis of reproductive data with the midge (Chironomus riparius)
Authors: Ducrot Virginie , Péry Alexandre R. R. , Mons Raphaël , Garric Jeanne 
Published: March 2005

Abstract
We propose a biologically based approach to analyze reproductive data for the midge (Chironomus riparius). We showed in a previous study that its larval development can be divided in two distinct phases regarding the use of energy: The somatic growth period and the gametic growth period. We hypothesize here the gametic period to be a crucial period for the energetic investment for reproduction. To test this, we performed several assays with different feeding programs. Our results confirmed that energetic investment for reproduction mainly occurs during the gametic growth period. We could then propose energy-based models to analyze reproductive data. We assumed the effects to result from a perturbation in the use of energy. Two models corresponding to different physiological modes of actions—decreased efficiency of feeding (i.e., feeding decrease model) or increased cost of egg production (i.e., egg-cost increase model)—were built and used for the analysis of data obtained after an exposure to an artificially copper-spiked sediment. During this experiment, different exposure patterns were performed to investigate whether effects on reproduction resulted mainly from an exposure that occurs during the gametic growth period or from an exposure that occurs during the somatic growth period. These exposure patterns led to similar effects on reproduction, which suggests that the toxicant-induced stress persists during the whole life cycle, even in case of exposure occurring only during part of it. Both the feeding decrease model and egg-cost increase model were able to describe the data. We showed that addition of copper in the sediment, even in low quantity (&lt;6.5 mg/kg), might affect reproduction at the individual level. If no-effect concentrations were derived from these results, this may lead to an overprotective value. A relevant no-effect concentration could be derived from further investigations at the population level.
Profiles of polychlorinated biphenyl congeners, organochlorine pesticides, and butyltins in southern sea otters and their prey
Authors: Kannan Kurunthachalam , Kajiwara Natsuko , Watanabe Mafumi , Nakata Haruhiko , Thomas Nancy J. , Stephenson Mark , Jessup David A. , Tanabe Shinsuke 
Published: March 2005

Abstract
Concentrations of organochlorine pesticides, polychlorinated biphenyl (PCB)congeners, and butyltins were measured in sea otters and selected prey species (invertebrates) collected from the California (USA) coast. Polychlorinated biphenyls, DDTs (sum of p,p′-dichlorodiphenyldichloroethylene [p,p-DDE], p,p′-dichlorodiphenyldichloroethane [p,p-DDD], andp,p′-DDT), and butyltins were the major contaminants found in sea otters and their prey. Lipid-normalized concentrations of PCBs and DDT in sea otter livers were 60- and 240-fold greater than those found in the prey. Great biomagnification of PCBs and DDT in sea otters is suggested to result from their high per-capita intake of diet compared with those of other marine mammals. Profiles of PCB congeners in sea otters and prey species suggest a great capacity of sea otters to biotransform lower-chlorinated congeners. Sea otters seem to possess a greater ability than cetaceans to metabolize PCBs. The 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents of non- and mono-ortho PCBs in sea otters and certain prey species were at or above the theoretical threshold for toxic effects.
Dissipation and effects of chlortetracycline and tylosin in two agricultural soils: A field-scale study in southern Denmark
Authors: Halling-Sørensen Bent , Jacobsen Anne-Marie , Jensen John , SengeløV Gitte , Vaclavik Elvira , Ingerslev Flemming 
Published: March 2005

Abstract
Presently, thereis a basic lack of information concerning the accumulationof antibacterial agent residues in agricultural soils. In this field study, performed in southern Denmark, we assess the dissipation of chlortetracycline (CTC), and tylosin A (TYL A) as a function of time. Field soils were classified as a sandy loam soil (field A) and a sandy soil (field B) and each field was sampled on six occasions during the 155-d experimental period from May to October 2000 for chemical analysis and counts of colony-forming units (CFU) detecting the level of aerobic bacteria surviving antibiotic exposure. Colony-forming units and TYL A were detected throughout the entire sampling period, with respective starting soil concentrations of 30 and 50 μg kg−1 soil declining to 1 and 5 μg kg−1 soil, on day 155. Compound half-lives (95% confidence limits in parentheses) were estimated for both fields and T1/2 for CTC was 25 d (20–34) and 34 d (28–42) in fields A and B, respectively, and T1/2 for TYL A was 67 d (54–86) and 49 d (40–64) in fields A and B, respectively. No significant difference was determined between compound half-lives on the two fields. The level of aerobic antibiotic-resistant bacteria in the soil over time and soil fauna community was assessed in relation to application of manure containing antibacterial agents to the agricultural fields. The level of both CTC- and TYL-resistant bacteria was affected in the soil by amendment of manure, but declined during the study to the same level as observed at the beginning.
Toxicity testing of 16 priority polycyclic aromatic hydrocarbons using Lumistox®
Authors: Loibner Andreas P. , Szolar Oliver H. J. , Braun Rudolf , Hirmann Doris 
Published: March 2005

Abstract
Hazard assessment of industrial sites contaminated with coal tar and its products usually focuses on selected pollutants such as the 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by the U.S. Environmental Protection Agency (U.S. EPA). The aim of this study was to investigate to which extent these 16 PAHs contribute to the Vibrio fischeri bioluminescence inhibition measured by the acute Lumistox® luminescent bacteria test. Five of the 16 PAHs—naphthalene(NA), acenaphthylene (ACY), acenaphthene (ACE), fluorene (FLU), and phenanthrene (PHE)—revealed inhibiting effects when measuring saturated aqueous solutions of these compounds. However, in elutriates of PAH-contaminated soils, the amount of leached PAHs was very low, and the 16 PAHs did not considerably contribute to the observed bioluminescence inhibition. Nevertheless, bioluminescence inhibition was higher for elutriates with increased PAH concentration indicating the presence of other toxicants that co-occur with the 16 PAHs. No evidence was observed for increased bioluminescence inhibition due to synergistic effects among PAHs as calculated on the basis of toxic units for an aqueous solution containing all 16 priority PAHs. Data suggest that the U.S. EPA PAHs play only a minor role in causing acute toxicity to V. fischeri when exposed to aqueous elutriates of PAH-contaminated soils.
Effect of carbon dioxide on uranium bioaccumulation in the freshwater clam Corbicula fluminea
Authors: Tran Damien , Massabuau Jean-Charles , Garnier-Laplace Jacqueline 
Published: March 2005

Abstract
This paper presents the results of a study examining the impact of CO 2 variations in water on uranium bioaccumulation in the bivalve Corbicula fluminea. The objectives were to evaluate the effect of CO2 on bivalve behavior (valve activity and ventilation rate) that are related to bioaccumulation and on the bioavailability of uranium carbonate complexes to the bivalve. It was demonstrated that at a total inorganic carbon concentration of CCO2 = 276 μmol/L, the daily valve opening duration and ventilation rate are significantly (p &lt; 0.05) lower than those obtained at 27.6 μmol/L (-28 and -47%, respectively). For both CCO2 values, exposure to uranium at 0.25 μmol/L had no impact on valve activity; however, ventilation decreased significantly compared to the reference condition, down to the same lower level for the two CCO2 conditions. Consequently, the quantity of uranium passing through the bivalve was identical for both CCO2 conditions. Thus, bivalve ventilatory and valve activity could not explain increased bioaccumulation in the gills and mantle measured under the low-CCO2 condition. Consequently, we suggest that the quantity of carbonate bound to the U fraction must be less bioavailable than other U species such as the free-ion UO2+2, which is in accordance with the biotic ligand model.
A comparison of chronic cadmium effects on Hyalella azteca in effluent-dominated stream mesocosms to similar laboratory exposures in effluent and reconstituted hard water
Authors: Stanley Jacob K. , Brooks Bryan W. , La Point Thomas W. 
Published: March 2005

Abstract
Laboratory single-species toxicity testsare used to assess the effects of contaminants onaquaticbiota. Questions remain as to how accurately these toxicity tests predict site-specific bioavailability and chronic effects of metals, particularly in streams that are effluent-dominated or dependent on effluent discharge for flow. Concurrent 42-d Hyalella azteca exposures were performed with cadmium and final treated municipal effluent in the laboratory and at the University of North Texas Stream Research Facility (Denton, TX, USA), a series of outdoor lotic mesocosms. An additional 42-d laboratory test was conducted with H. azteca to evaluate Cd toxicity in reconstituted hard water (RHW). Endpoints included Cd body burden, survival, growth, and reproduction. Calculated average bioaccumulation factors were: 2,581 (stream mesocosm test) &lt; 3,626 (laboratory effluent) &lt; 7,382 (laboratory RHW). The 42-d survival lowest-observed-effect concentrations (LOECs) were 0.94, 4.53, and 22.97 μg/L for the laboratory RHW, laboratory effluent, and stream mesocosm exposures, respectively. Baseline growth (dry wt) and reproduction (young female−1) among the three exposures followed the relationship: Stream mesocosms &gt; laboratory effluent &gt; laboratory RHW. Differences among response variables in the three tests likely resulted from increased food sources and decreased Cd bioavailability in lotic mesocosms. Our results demonstrate that laboratory toxicity tests may overestimate chronic toxicity responses of H. azteca to Cd in effluent-dominated streams.
Metamorphic inhibition of Xenopus laevis by sodium perchlorate: Effects on development and thyroid histology
Authors: Tietge Joseph E. , Holcombe Gary W. , Flynn Kevin M. , Kosian Patricia A. , Korte Joseph J. , Anderson Leroy E. , Wolf Douglas C. , Degitz Sigmund J. 
Published: March 2005

Abstract
The perchlorate anion inhibits thyroid hormone (TH) synthesis via inhibition of the sodium-iodide symporter. It is, therefore, a good model chemical to aid in the development of a bioassay to screen chemicals for affects on thyroid function. Xenopus laevis larvae were exposed to sodium perchlorate during metamorphosis, a period of TH-dependent development, in two experiments. In the first experiment, stage 51 and 54 larvae were exposed for 14 d to 16, 63, 250, 1,000, and 4,000 μg perchlorate/L. In the second experiment, stage 51 larvae were exposed throughout metamorphosis to 8, 16, 32, 63, and 125 μg perchlorate/L. Metamorphic development and thyroid histology were the primary endpoints examined. Metamorphosis was retarded significantly in the first study at concentrations of 250 μg/L and higher, but histological effects were observed at 16 μg/L. In the second study, metamorphosis was delayed by 125 μg/L and thyroid size was increased significantly at 63 μg/L. These studies demonstrate that inhibition of metamorphosis readily can be detected using an abbreviated protocol. However, thyroid gland effects occur at concentrations below those required to elicit developmental delay, demonstrating the sensitivity of this endpoint and suggesting that thyroidal compensation is sufficient to promote normal development until perchlorate reaches critical concentrations.
Influence of dimethoate on acetylcholinesterase activity and locomotor function in terrestrial isopods
Authors: Engenheiro Elizabeth L. , Hankard Peter K. , Sousa Jose P. , Lemos Marco F. , Weeks Jason M. , Soares Amadeu M. V. M. 
Published: March 2005

Abstract
Locomotor behavior in terrestrial organisms is crucial for burrowing, avoiding predators, food seeking, migration, and reproduction; therefore, it is a parameter with ecological relevance. Acetylcholinesterase (AChE) is a nervous system enzyme inhibited by several compounds and widely used as an exposure biomarker in several organisms. Moreover, changes in energy reserves also may indicate an exposure to a stress situation. The aim of this study is to link biomarkers of different levels of biological organization in isopods exposed to increasing doses of dimethoate in semifield conditions. Locomotor parameters, AChE activity, and energy reserves (lipid, glycogen, and protein contents) were evaluated in the isopod Porcellio dilatatus after 48-h and 10-d exposure to dimethoate-contaminated soil. Results showed a clear impairment of both locomotor and AChE activity during the entire study, although effects were more pronounced after 48 h. Most locomotor parameters and AChE activity showed a clear dose-response relationship. By contrast, no clear trend was observed on energetic components. A positive and significant relationship was found between AChE activity and those locomotor parameters indicating activity, and the opposite was observed with those locomotor parameters indicating confusion and disorientation. The results obtained in this study enhance the importance of linking biochemical responses to parameters with ecological relevance at individual level, the value of locomotor behavior as an important marker to assess effects of toxicants, and also the usefulness and the acquisition of ecological relevance by AChE as a biomarker, by linking it with ecologically relevant behavioral parameters.