bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting ready biodegradability in the Japanese ministry of international trade and industry test
Authors: Tunkel Jay , Howard Philip H , Boethling Robert S , Stiteler William , Loonen Helene
Published: March 2010

Two new predictive models for assessing a chemical's biodegradability in the Japanese Ministry of International Trade and Industry (MITI) ready biodegradation test have been developed. The new methods use an approach similar to that in the existing BIOWIN© program, in which the probability of rapid biodegradation is estimated by means of multiple linear or nonlinear regression against counts of 36 chemical substructures (molecular fragments) plus molecular weight (mol wt). The data set used to develop the new models consisted of results (pass/no pass) from the MITI test for 884 discrete organic chemicals. This data set was first divided into randomly selected training and validation sets, and new coefficients were derived for the training set using the BIOWIN fragment library and mol wt as independent variables. Based on these results, the fragment library was then modified by deleting some fragments and adding or refining others, and the new set of independent variables (42 substructures and mol wt) was fit to the MITI data. The resulting linear and nonlinear regression models accurately classified 81% of the chemicals in an independent validation set. Like the established BIOWIN models, the MITI models are intended for use in chemical screening and in setting priorities for further review.
Potential for octylphenol to biodegrade in some english rivers
Authors: Johnson Andrew C , White Craig , Bhardwaj Lal , Jürgens Monika D
Published: March 2010

To study octylphenol biodegradation, samples of river water and sediments were taken from the Aire and Calderr vers in the United Kingdom, running through urban/industrial areas, as well as the Thames River running through a more rural area. Using laboratory microcosms, half-lives of 7 to 50 d were obtained for the water samples, with most curves fitting a zero-order reaction. The Calder River was sampled at four separate points along a 45-km length, encompassing rural to increasingly urban/industrial reaches. Little degradation was observed in the sample from the upland/rural reach, while half-lives of 8 to 13 d were seen in the more urban/industrial reaches. Mineralization of the phenyl ring, detected by evolution of 14CO2 from ring-labeled octylphenol, was only observed in water from the Calder River sample. Degradation rate was similar for a range of concentrations from 0.3 to 100 μ,g/L when tested with river water from the Thames River. No degradation was observed over 83 d when bed sediments were spiked with octylphenol and incubated under anaerobic conditions.
Algal growth inhibition test in filled, closed bottles for volatile and sorptive materials
Authors: Mayer Philipp , Nyholm Niels , Verbruggen Eric MJ , Hermens Joop LM , Tolls Johannes
Published: March 2010

Exposure concentrations of many hydrophobic substances are difficult to maintain in algal growth inhibition tests performed in open agitated flasks. This is partly because such compounds tend to volatilize from aqueous solution and partly because of sorption to the algal biomass as well as to the test container. A simple filled closed bottle test with low algal densities and bicarbonate enrichment is described here as an approach to minimize the loss of test material from solution. The algal medium was enriched with 300 mg NaHCO3/L, the pH was adjusted to 7.0 by addition of HCl, and the resulting dissolved CO2 concentration supported maximum algal growth rates without pH drift for algal densities up to 4 mg dry weight/L. Two-day toxicity tests with kerosene were performed with this new test design and compared with an open bottle test and with a closed bottle test with headspace. Exposure concentrations of the volatile fraction of kerosene decreased by 99% in the open test, by 77% in the closed flask test with headspace, and by 16% in the filled closed bottle test. Algal growth inhibition was observed at much lower additions of kerosene in the new test design because of the improved maintenance of a constant exposure.
Developmental toxicity of estrogenic alkylphenols in killifish (Fundulus heteroclitus)
Authors: Kelly Sue A , Giulio Richard T. Di
Published: March 2010

Estrogenic alkylphenols have been identified in the aquatic environment, and concern has arisen over the ability of these compounds to interact with and potentially disrupt vertebrate endocrine systems. Here we report that waterborne nonylphenol (NP) and 4-tert-octylphenol (4-t-OP) are toxic to the embryos and larvae of Fundulus heteroclitus, an estuarine teleost, causing both lethal and sublethal developmental abnormalities. Hatch success in surviving embryos is also adversely affected by alkylphenol exposure. Correlation analysis has indicated that decreased hatch success is strongly correlated to deformities in the torso/abdomen and tail of embryos. Larval exposure to the alkylphenols demonstrates that NP and 4-t-OP are lethal at concentrations an order of magnitude less than those lethal to embryos (NP larval 96-h LC50 = 0.95 μM [204 μg/L]; NP embryo 96-h LC50 = 24 μM [5 mg/L]). In evaluating the role of estrogenicity in developmental toxicity of the alkylphenols, we have found that tamoxifen, an estrogen receptor antagonist, can prevent embryo-lethality for NP and 4-t-OP While these embryos survive, some sublethal abnormalities are still evident, particularly in the torso and tail. The results of these studies suggest that the alkylphenols have the potential to cause developmental toxicity in aquatic organisms and that this may occur through disruption of estrogen-based signals.
Amphibians as indicators of wetland quality in wetlands formed from oil sands effluent
Authors: Pollet Ingrid , Bendell-Young Leah I
Published: March 2010

Fort McMurray, Alberta, Canada, is home to the largest oil sands mining operation in the world. Two of the companies currently mining the oil sands hope to use wetlands formed from oil sands effluent as part of their reclamation strategy required at mine closure. To evaluate the ability of these created wetlands to sustain amphibians, one population of Bufo boreas tadpoles and three different populations of Rana sylvatica tadpoles were exposed to oil sands process-affected water representative of a range of effluents expected to occur on the oil sands lease site at mine closure. Endpoints used to assess the response of the tadpoles to the process-affected waters included survival, growth, rate of development, and frequency of physical deformities. Bufo boreas held in process-affected waters displayed significantly reduced growth and prolonged developmental time (days to metamorphosis) as compared to those held in reference waters. The response of the three separate populations of R. sylvatica were population dependent. Two of the three populations responded similarly, demonstrating decreased survival and significantly reduced rates of growth when held in process-affected waters as compared to reference waters; the third was highly sensitive, displaying no growth and extremely poor survival in all exposures, suggesting different tolerances to the process-affected waters among different R. sylvatica tadpole populations. Amphibians such as B. boreas and R. sylvatica were sensitive indicators of effluent quality. Based on the effluents used in this study, wetlands formed from oil sands effluent will not support viable amphibian populations.
Classifying probabilities of acute toxicity in marine sediments with empirically derived sediment quality guidelines
Authors: Long Edward R , MacDonald Donald D , Severn Corinne G , Hong Carolyn B
Published: March 2010

Matching, marine sediment chemistry, and toxicity data(n = 1,513), compiled from three studies conducted in the United States, were analyzed to determine both the frequency of acute toxicity to amphipods and average percentage survival in laboratory bioassays within ranges in toxicant concentrations. We determined that the probability of observing acute toxicity was relatively low (<10%) and that average control-adjusted survival equaled or exceeded 92% in samples in which sediment quality guidelines were not exceeded. Both the incidence of toxicity increased and average survival decreased as chemical concentrations increased relative to the guidelines. In sediments with highest contaminant concentrations, 73 to 83% of the samples were highly toxic, and average control-adjusted amphipod survival was 37 to 46%. Results of this study confirm that the relationships between sediment chemical concentrations and toxicity reported in a previous study were robust. Further, they indicate that numerical guidelines for saltwater sediments can be used to estimate the probability of observing toxic effects in acute amphipod tests.
Bioavailability of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in rats from naturally contaminated soils—preliminary evaluation of the influence of soil parameters
Authors: Billeret Mikakline , Berny Philippe , Mazallon Michelle , Buronfosse Thierry
Published: March 2010

In order to assess the bioavailability of organic pollutants (polycyclic aromatic hydrocarbons [PAHs],polychlorobiphenyls [PCBs]) in polluted soils, male laboratory rats were exposed during 3 d and one night to two types of soil. These soils were highly polluted by PAHs (F2 soil) and by PCBs (S3 soil). They were diluted (1:1) either with an organic or a mineral matrix. Those matrices had different characteristics, and the purpose was to determine the influence of several soil parameters (organic matter) on the pollutants' bioavailability. Two categories of biomarkers were used: pollutant's burden and activities of microsomal liver and lung's cytochrome P450 1A-monooxygenase, namely, ethoxyresorufin-O-deethylase (EROD) activities. Absorption differed between exposed rats, depending on the pollutant and on the organ considered. Their EROD activity was well correlated with PAH and PCB burden, respectively. Moreover, EROD activity and pollutants burden in both organs depended on the dilution performed. The PAH bioavailability was lower after a dilution with organic matrices. In fact, those matrices had both the highest organic matter concentration and the lowest granulometry and appeared to adsorb more. Thus, organic pollutant bioavailability varies according to the soil characteristics. The most important parameters seemed to be organic matter and granulometry. The EROD activity and CYP1A1 dosage were good biomarkers and closely monitored the differences in bioavailability.
Estimations of vapor pressure and activity coefficients in water and octanol for selected aromatic chemicals at 25°C
Authors: Lee Sum Chi , Hung Hayley , Shiu Wan-Ying , Mackay Donald
Published: March 2010

A roupcontribution method is developed to estimate the supercooled liquid vapor pressure and the activity coefficients in water and octanol at 25°C of 98 selected monoaromatic compounds, many of which are or have been produced as chlorinated by-products in the manufacture of pulp and paper. The set includes alkylphenols, chlorinated phenols, anisoles, catechols, cymenes, guaiacols, syringols, and veratroles. The method can be used to estimate vapor pressures, solubilities in water, octanol-water partition coefficients, octanol-air partition coefficients, and Henry's law constants. It can also be used for predicting these partition coefficients as well as solubilities and vapor pressures for these and structurally similar compounds.
Brominated analogs of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone: Preparation of 3-chloro-4-(bromochloromethyl)-5-hydroxy-2(5H)-furanone and mutagenicity studies
Authors: Ramos Isabel , Lloveras Maia , Solans Xavier , Huici Alicia , Messeguer Angel
Published: March 2010

The brominated hydroxyfuranones sructurally related to the potent mutagen MXnamely3-chloro-4-(bromochlorome-thyl)-5-hydroxy-2(5H)-furanone (BMX-1), has been synthesized and characterized. The mutagenic activity of this bromohydro-xyfuranone together with those of its analogs BMX-2 and BMX-3 has been assessed by employing the Ames test with the Salmonella typhimurium strains TA98 and TA100. The mutagenic potencies in TA100 without S9 metabolic activation were 22.05 ± 3.15 revertants/ng for BMX-1, 28.64 ± 2.65 revertants/ng for BMX-2, and 37.29 ± 5.73 revertants/ng for BMX-3, whereas in the TA98 strain without metabolic activation, they were six- to ninefold lower. Studies carried out on the stability of these halogenated furanones suggest that the mutagenic activity observed is more related to the cyclic form of these derivatives.
Isomer-specific polychlorinated biphenyl determination in cetaceans from the mediterranean sea: Enantioselective occurrence of chiral polychlorinated biphenyl congeners
Authors: Jiménez Olga , Jiménez Begoña , Gonzalez Maria José
Published: March 2010

Isomer-specific concentrations of 41 polychlorinated biphenyls (PCBs) and the enantiomeric ratios (ER) of nine chiral PCBs were determined in the liver of four cetacean species—Risso's dolphin (Grampus griseus), bottlenose dolphin (Tursiops truncatus), fin whale (Balaenoptera physalus), and long-finned pilot whale (Globicephala melaena)—found dead in the Mediterranean Sea. The total PCB concentration (sum of 41 congeners) ranged from 484 to 63,200 ng/g wet weight. The 2,3,7,8 tetra-chlorodibenzo-p-dioxin (TCDD) toxic equivalents (TEQs), as defined by the World Health Organization (WHO), ranged from 4.3 to 1,454 pg/g wet weight. The contribution of mono-ortho PCBs was consistently higher than non-ortho PCB congeners, in whale species, whereas in dolphins this predominance was not so clear. The PCB profiles were dominated by congeners 138, 153, and 180 in almost all the investigated samples. Comparison of PCB profiles by using principal component analysis allowed to separate the species into different groups. Polychlorinated biphenyls 170 and 180 seem to be eliminated by the two whale species, and PCB 180 also seems to be eliminated by Risso's dolphins. The PCBs 95, 132, 149, and 176 revealed an enantiomeric excess of the second eluted enantiomer in almost all the cetaceans investigated, where 136 and 174 were racemic or almost racemic. It is the first time that an enantiomeric excess of PCB 84 and 91 has been reported in biological samples. Although it was only possible to calculate them in two dolphin liver samples, the high values of enantiomeric excess found are surprising (86.3 and 32% for PCB 91 and 84, respectively).
Evidence of two metabolic pathways for degradation of 2-methylphenanthrene by Sphingomonas sp. strain (2MPII)
Authors: Budzinski Hélène , Nadalig Thierry , Raymond Natalie , Matuzahroh Ni' , Gilewicz Michèle
Published: March 2010

A pure bacterial strain of Sphingomonas sp. DSM 11572 (named 2MPII) has been isolated from a Mediterranean coastal sediment. This strain is able to use 2-methylphenanthrene (2-MP) as a growth substrate. In order to understand the degradation processes and their selectivity, we have elucidated the metabolic pathways of 2-MP degradation. In this respect, in this paper, we report the identification of several metabolites resulting from the oxidation of 2-MP by the Sphingomonas sp. Metabolites of 2-MP, identified by gas chromatography coupled to mass spectrometry in culture media, belong to two distinct metabolic pathways. The first pathway involves, in the first step, the double hydroxylation of an aromatic ring catalyzed by a di-oxygenase. This pathway generates before the opening of the aromatic ring. The exact double hydroxylation positions have not been totally elucidated. The second pathway is initiated by the hydroxylation of the methyl side chain by a mono-oxygenase. It leads, by the oxidation of the methyl group, to the formation of alcohol, aldehyde, and carboxylic acid.
Importance of maternal transfer of the photoreactive polycyclic aromatic hydrocarbon fluoranthene from benthic adult bivalves to their pelagic larvae
Authors: Pelletier Marguerite C , Burgess Robert M , Cantwell Mark G , Serbst Jonathan R , Ho Kay T , Ryba Stephan A
Published: March 2010

Laboratory experiments were conducted to determine if maternal transfer of polycyclicaromatichydrocarbons (P AH) from benthic adult bivalves could result in phototoxicity to their pelagic larvae when exposed to ultraviolet light (UV). In these experiments, adult bivalves were exposed to water or sediments amended with the model photoreactive PAH, fluoranthene. Elevated adult fluoranthene tissue concentrations were correlated with embryo concentrations. Embryonic mortality was enhanced by exposure to ultraviolet light when adult tissue fluoranthene levels were greater than 5,000 μg/g lipid. While the exposure concentrations used in this experimental system were high, ultraviolet light exposure levels were low. Also, some of the PAHs are more potent than the model compound used in this study. These results indicate that maternal transfer of photoactive PAHs from organisms living in contaminated sediments may represent a significant adverse effect to populations of benthic bivalves.
Protective effects of calcium against chronic waterborne cadmium exposure to juvenile rainbow trout
Authors: Hollis Lydia , McGeer James C , McDonald D Gordon , Wood Chris M
Published: March 2010

Juvenile rainbow trout (Oncorhynchus mykiss [Walbaum]) on 1% daily ration were exposed to 0 (control) or 2 μg of cadmium as Cd(NO3)2·4H2O per liter added to four different calcium (Ca) concentrations: 260 (background), 470 (low), 770 (medium), or 1200 (high) μM of Ca added as Ca(NO3)2·4H2O in synthetic soft water for 30 d. Mortality was highest (∼80%) in the background + Cd treatment. Approximately 40% mortality was observed in the low + Cd exposure; mortality was 10% or less for all other treatments. No growth effects were seen for any of the exposures. Kidneys accumulated the greatest concentration of Cd during the 30 d, followed by gills and livers. Accumulation of Cd in gills, kidney, and liver decreased at higher water Ca concentrations. No differences in whole-body or plasma Ca concentrations were found. Swimming performance was impaired in the low + Cd-exposed fish. Influx of Ca2+ into whole bodies decreased as water Ca concentrations increased; influx of Ca2+ into background + Cd-treated fish was significantly reduced compared to that in control fish. Experiments that measured uptake of new Cd into gills showed that the affinity of gills for Cd (KCd-gill) and the number of binding sites for Cd decreased as water Ca concentrations increased. Acute accumulation of new Cd into gills and number of gill Cd-binding sites increased with chronic Cd exposure, whereas the affinity of gills for Cd decreased with chronic Cd exposure. Longer-term gill binding (72 h) showed reduced uptake of new Cd at higher water Ca levels and increased uptake with chronic Cd exposure. Complications were found in applying the biotic ligand model to fish that were chronically exposed to Cd because of discrepancies in the maximum number of gill Cd-binding sites among different studies.
Factors affecting risk assessment of small mammals to pesticides
Authors: Edge W Daniel , Schauber Eric M
Published: March 2010

The quotient method (QM), a laboratory-based risk assessment methodology used by the U.S. Environmental Protection Agency to evaluate pesticides for registration and use, has not been thoroughly field-tested and its performance has not always been reliable. Our objective was to compare predictions of risk using the QM with results from small mammal field studies to identify factors that cause variation in the performance of the QM. We regressed estimated mortality of herbivorous gray-tailed voles (Microtus canicaudus) and omnivorous deer mice (Peromyscus maniculatus) against predictions of mortality based on LC50 probit analyses for pesticide concentrations in spray-tank mixtures and residues on the top and bottom 15 cm of alfalfa plants. Predictions of risk generally were correlated with estimated mortality in the field, but slopes often differed significantly from the predicted 1:1 relationship and were much greater than 1.0 for several relationships during the 1993 experiment. Risk predictions may be influenced by a number of factors, including estimation of estimated environmental concentration (EEC), vegetation structure, weather patterns, species of concern, and demographic characteristics of the exposed populations. More accurate risk assessments may be accomplished by improving vegetation nomogram estimates of EEC and by incorporating vegetation structure and differences in natural history among species into QM predictions. Weather following application and the demographic characteristics of the exposed populations are likely to remain unknown and will cause imprecision in risk assessments.
Effects of dietary polychlorinated biphenyl exposure on energetics of white-footed mouse, Peromyscus leucopus
Authors: Voltura Mary Beth , French John B
Published: March 2010

Energy budgets have provided physiological ecologists with a vital link between environmental variables and individual performance and should also prove useful to ecotoxicologists in understanding the effects of sublethal exposure in the field. Exposure to toxic compounds is likely to be metabolically expensive and may result in a trade-off between energy spent to detoxify and excrete contaminants and energy allocated to growth or reproduction. To quantify the energetic cost of polychlorinated biphenyl (PCB) exposure, we fed captive white-footed mice (Peromyscus leucopus) diets containing PCBs (2:1 Aroclor® 1242:1254) at levels of 0, 0.1, 10, and 25 ppm (mg PCBs/kg food). After six weeks on the diets, there were no differences in food intake (g/d), diet digestibility (%), or body mass related to the level of dietary PCBs. This indicated that short-term exposure to PCBs did not cause a detectable increase in energy need as measured by voluntary food intake. We continued to feed mice the PCB-containing diets for one year, at which time we repeated the food intake trial, and also measured oxygen consumption at 20 and 30°C. After one year, all mice had gained mass, but mice on the 25-ppm diet tended to be heavier than mice in the other groups. Compared to the control group, mice on the 25-ppm diet had higher food intake (4.1 vs 3.7 g/d; p = 0.06) and higher oxygen consumption at 30°C (40.1 vs 36.6 ml O2/h; p = 0.01). These results suggest that there is an energetic cost to long-term contaminant exposure that, when combined with other environmental stresses, may influence patterns of energy acquisition and allocation.
Endocrine responses ofFundulus heteroclitusto effluent from a bleached-kraft pulp mill before and after installation of reverse osmosis treatment of a waste stream
Authors: Dubé Monique G , MacLatchy Deborah L
Published: March 2010

Implementation of process changes on the nonbleaching side of bleached kraft pulp mill (BKPM) operations has increased in recent years to maximize resource use and to minimize residual environmental effects of discharged effluents. The objective of this study was to determine if reverse osmosis (RO) treatment of evaporator and digester clean condensates reduced or removed the effects of a BKPM effluent on reproductive endocrine function of the estuarine killifish, Fundulus heteroclitus (mummichog). Comparison of data collected before (1997) and after (1998), the years of the process change, showed that the potential of the combined mill effluent to depress plasma testosterone levels after 30 and 57 d of exposure to an environmentally relevant effluent concentration (1%) was reduced after RO treatment of condensates. However, in vitro production of some sex steroids was depressed with a 1% effluent exposure after the process change. In addition, in 1998, depression of plasma testosterone levels in effluent-exposed fish was present at higher effluent concentrations (5%). These results are significant because they suggest that condensates may be a source of endocrine-disrupting compounds in BKPM effluents and RO may reduce their discharge.
Development of an in vivo screening assay for estrogenic chemicals using juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Thorpe Kare I. , Hutchinson Thomas H , Hetheridge Malcolm J , Sumpter John P , Tyler Charles R
Published: March 2010

In this study, the Organisation for EconomicCooperationand Development (OECD) Test Guideline 204 was adapted for the development of an in vivo screen for detecting estrogenic activity using juvenile rainbow trout (Oncorhynchus mykiss). The influence of feeding ration and the effect of reference estrogenic chemicals on somatic growth, gonadosomatic index, hepa-tosomatic index, and plasma vitellogenin concentrations were evaluated over 21 d. A feeding ration of 4% body weight per day resulted in temporal increases in body weight, hepatosomatic index, and plasma vitellogenin concentration in both males and females. A feeding ration of 1% did not induce any changes in the measured endpoints and was adopted for the subsequent estrogen exposures. Exposure of juvenile female fish to 17β-estradiol and 4-tert-nonylphenol produced concentration-dependent inductions of plasma vitellogenin that were optimal after 14 d, with lowest observed effect concentrations of 8.9 ng/L and 16 μg/L, respectively. Methoxychlor also induced synthesis of plasma vitellogenin with a 14-d lowest observed effect concentration of 9.8 μg/L. Higher concentrations of methoxychlor were toxic to fish. Increases in the hepatosomatic index occurred on day 14 in fish exposed to 244 ng/L 17β-estradiol and 53μg/L 4-tert-nonylphenol. None of the compounds tested caused detectable changes in the gonadosomatic index. Vitellogenin induction in juvenile trout was sensitive to estrogenic chemicals, occurred rapidly, and the response was highly consistent between experiments (coefficient of variation = 4.5% for the 17β-estradiol positive control). The 14-d juvenile fish assay offers a sensitive and robust in vivo screening method for estrogen-active substances.
Impact of animal waste lagoon effluents on chlorpyrifos degradation in soils
Authors: Huang Xinjiang , Lee Linda S , Nakatsu Cindy
Published: March 2010

Animal-derived lagoon effluents are a good source of inorganic nutrients and organic matter; however, they may impact the degradation and transport of soil-applied pesticides. The degradation of chlorpyrifos in poultry-, swine-, and cow-derived effluents and effluent-soil matrices were studied using batch and column incubation studies. Chlorpyrifos was degraded by aerobic microbial processes in animal-derived lagoon effluents. Microbial community analysis by denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16S ribosomal ribonucleic acid genes showed that a single band became dominant in effluent during chlorpyrifos degradation. In soils, both biotic and abiotic degradation contributed significantly to the overall dissipation of chlorpyrifos. Large differences in degradation rates were observed between soils, with the fastest rate observed in soil with higher pH and cation-exchange capacity. Effluents appeared to have only a minor effect on chlorpyrifos degradation in soils, although effluent-induced increases in soil-solution pH over time may enhance hydrolysis by a few percent in low-pH soils. Soil properties, not effluent properties, appear to control chlorpyrifos degradation under laboratory conditions; however, the impact on changes in soil properties and microbial ecology with long-term effluent irrigation warrants further investigation.
Mutagenicity of trinitrotoluene and metabolites formed during anaerobic degradation by Clostridium acetobutylicum ATCC 824
Authors: Padda Ranjit S , Wang Chuan Yue , Hughes Joseph B , Bennett George N
Published: March 2010

2, 4, 6-Trinitrotoluene (TNT) and its metabolites formed during anaerobic degradation are mutagenic in Salmonella typhimurium TA98 and TA100 when checked in the absence of rat liver activation system (S9). The monohydroxylamino derivatives that are formed as first-step intermediates of the pathway are less mutagenic than TNT, but the dihydroxylamino derivative that is the second intermediate is much more mutagenic than the parent compound. Whereas TNT is very stable under aerobic as well as anaerobic conditions, the hydroxylamine derivatives are not. The dihydroxylamino derivative of TNT that is the most mutagenic is less stable compared with the monohydroxylamino derivatives of TNT.
Dialysis minipeeper for measuring pore-water metal concentrations in laboratory sediment toxicity and bioavailability tests
Authors: Doig Lorne , Liber Karsten
Published: March 2010

Whave modifieda classical peeper (dialysiscell)design to create minipeepers that are ofconvenient sze for direct pore-water sampling in laboratory sediment toxicity and bioavailability tests. A series of experiments placing peepers in nickel and zinc solutions, two size fractions of nickel-spiked sand, and two field-collected, nickel-spiked sediments, were conducted to evaluate peeper efficacy in measuring overlying water and pore-water metal concentrations. In water-only experiments, concentrations in the peeper cells were not significantly different from those in the surrounding solution by 48 and 96 h for nickel and zinc, respectively. Peeper cells in the sand experiments equilibrated with the surrounding pore water in ≤120 h. In both trials with natural sediment, peeper equilibrium occurred in ≤48 h. Nickel flux into the peeper cells during the first hour of experimentation showed that the rate of equilibration was initially related to media porosity. In fine sand and natural sediment, equilibration was influenced not only by nickel diffusion into the peeper cells, but also by a decrease in concentrations of nickel in pore water due to sediment sorption and diffusion into overlying water. This shortened the time required to reach equilibrium by reducing the difference between the peeper cell and the surrounding pore-water solution. Overall, minipeepers equilibrated with the surrounding pore water or overlying water within a time period sufficiently short to allow for the use of minipeepers in routine sediment toxicity and metal bioavailablity experiments. Sampling precision using minipeepers was comparable (CV = 10.8 %) to that obtained by conventional sediment centrifugation and filtration (CV = 10.5 %).
Combined effects between sediment-associated sulfur and lubricant oil on Bacillus cereus
Authors: Tiemann Jan , Ahlf Wolfgang
Published: March 2010

An artificial sediment was spiked with elemental sulfur and a lubricant oil. The measured toxicity in a microbial solid-phase test with Bacillus cereus was markedly enhanced when compared with the effects of the individual toxicants. The joint action was interpreted as augmentation of elemental sulfur toxicity due to facilitation of its solubility by oil components. These results show the demand for consideration of the entire contamination where sediment toxicities are to be assessed.
Mixture toxicity of copper and diazinon to larvae of the mayfly (Ephoron virgo) judging additivity at different effect levels
Authors: van der Geest Harm G , Greve Gerdit D , Boivin Marie-Elen , Kraak Michiel H S , van Gestel Cees A M
Published: March 2010

The toxic unit concept is commonly applied for determining the effects of a mixture of toxicants. Use of this concept is, however, limited to compounds with similarly shaped dose-response relationships. In the present study, a method is proposed to gain insight regarding the influence of differences in the shapes of dose-response relationships on the applicability of the concentration-addition model by judging additivity at different effect levels. To this purpose, two model toxicants with different modes of action and dose-response relationships were selected: copper, and diazinon. Using mortality of the mayfly (Ephoron virgo) as the endpoint, it was demonstrated that the two compounds act in a less-than-concentration-additive manner. Application of the proposed calculation method revealed that the less-than-concentration-addition effect was independent of the effect level on which the mixture was judged.
More male fish embryos near a pulp mill
Authors: Larsson D G Joakim , Ha¨︂llman Hans , Fo¨︂rlin Lars
Published: March 2010

Exposure to endocrine disrupters during early life stages may cause severe long-term effects. One process likely to be affected is sexual differentiation, which in fish can be influenced by both exogenous androgens and estrogens. To investigate if sexual differentiation is disturbed in wild fish exposed to pollutants, we studied embryonic sex ratios in a viviparous, gonochoristic fish species, the eelpout (Zoarces viviparus), whose embryos complete sexual differentiation before birth. The normal sex ratio of the eelpout was close to 50% females at four reference stations. In the effluent gradient of a large Swedish pulp mill, however, the sex ratios were significantly male biased. In light of the endocrine disturbances found near several pulp and paper mills in Europe and North America, it is suggested that endocrine disrupters may interfere with sexual differentiation and, thereby, affect the reproductive potential of fish populations.
Acute and chronic toxicity of nitrate to fathead minnows (Pimephales promelas), ceriodaphnia dubia, andDaphnia magna
Authors: Scott George , Crunkilton Ronald L
Published: March 2010

Increasing concentrations of nitrate in surface water and groundwater are becoming a worldwide concern, yet little information has been published on toxicity of nitrate to common organisms used for toxicity testing. The acute and chronic toxicity of nitrate (NO3-N) to Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas was investigated in 48-h to 17-d laboratory exposures. The 48-h median lethal concentration (LC50) of nitrate to C. dubia and D. magna neonates was 374 mg/L NO3-N and 462 mg/L NO3-N. The no-observed-effect concentration (NOEC) and the lowest-observed-effect concentration (LOEC) for neonate production in C. dubia were 21.3 and 42.6 mg/L NO3-N, respectively. The NOEC and LOEC values for neonate production in D. magna were 358 and 717 mg/L NO3-N, respectively. The 96-h LC50 for larval fathead minnows (P. promelas) was 1, 341 mg/L NO3-N. The NOEC and LOEC for 7-d larval and 11-d embryo-larval growth tests were 358 and 717 mg/L NO3-N, respectively. Additional exposure of breeding P. promelas and their fertilized eggs to nitrate did not increase susceptibility further. The LC50 values for all species tested were above ambient concentrations of nitrate reported for surface water. However, the LOEC for C. dubia was within the range of concentrations that could be found in streams draining areas under extensive agricultural cultivation.
Effects of short-term pulsed ammonia exposure on fish
Authors: Milne Ian , Seager John , Mallett Mike , Sims Ian
Published: March 2010

Two series of laboratory experiments were undertaken to investigate the influences of exposure duration and frequency on the toxicity of short-term pulses of ammonia to rainbow trout (Oncorhynchus mykiss Walbaum) and brown trout (Salmo trutta L.). For the investigation of exposure duration, rainbow trout were exposed to a range of unionized ammonia concentrations in single pulses of 1, 6, or 24 h, and mortality was recorded as the endpoint. For the investigation of exposure frequency, brown trout were exposed to repeated sublethal ammonia pulses of different concentrations either once or three times weekly over a period of 53 d to simulate intermittent pollution episodes. A range of endpoints were measured, including growth, gill condition, blood indices, and organ-to-body weight ratios. The results suggest that exposure duration and frequency are both important factors influencing the severity of effect in fish exposed to short-term ammonia peaks. Growth, gill condition, organ weights, and hematocrit were all significantly affected by repeated exposures, particularly at the higher exposure frequency. The results of this study confirm that the duration and return period of transient pollution events are critical dimensions when considering the development of environmental quality standards for intermittent pollution.
Comparison of polycyclic aromatic hydrocarbon and polychlorinated biphenyl dynamics in benthic invertebrates of Lake Erie, USA
Authors: Gewurtz Sarah B , Lazar Rodica , Douglas Haffner G.
Published: March 2010

hedistributionpatternsofpolycyclicaromatichydrocarbons(PAH)andpolychlorinatedbiphenyls(PCBs) were determined in four benthic invertebrate species of western Lake Erie, USA, to assess and compare the processes governing the exposure dynamics of these two classes of contaminants. Significant differences in the sum of 17 PAH compounds were observed among the four species, with mayflies containing the highest PAH body burden, followed by dreissenid mussels, amphipods, and crayfish. For PCBs, mayflies contained significantly higher concentrations of the sum of 39 PCB congeners than the other organisms, and dreissenids had higher levels than crayfish. No significant differences were found in the SPCB levels between dreissenids and amphipods or between amphipods and crayfish. For PCBs, the relationship between biota-sediment accumulation factors (BSAFs) and log Kow followed a parabolic pattern indicative of selective bioaccumulation. In contrast, BSAFs for PAHs were inversely related to log Kow, suggesting that metabolism of the higher Kowcompounds was occurring. These results support the conclusion that mayflies and dreissenids play major roles in the transfer of PAHs and PCBs to upper trophic levels, and they demonstrate that the exposure dynamics of PAHs and PCBs are different in the benthic components of aquatic food webs.
Toxicity, metal uptake, and accumulation of phytochelatins inSilene vulgarisexposed to mixtures of cadmium and arsenate
Authors: Sneller F Else C. , Van Heerwaarden Luisa M , Schat Henk , Verkleij Jos A C
Published: March 2010

The mixture effects of arsenate and cadmium were studied in Silene vulgaris (Moench) Garcke. The results show that the toxicity of the mixtures, measured as inhibition of root elongation, increased with increasing concentrations, ranging from nonadditive or slightly additive to synergistic. The elements did not influence each other's uptake. This was as expected, considering the differences in uptake mechanisms between both elements. Concentrations of detoxifying phytochelatins (PCs) were additive, with respect to both external and root-internal metal concentrations. However, at high exposure concentrations, the plants metabolism collapsed, resulting in very low PC concentrations.
Bioavailability of chlorinated dibenzo-p-dioxins and dibenzofurans to dungeness crab (Cancer magister) at marine pulp mill sites in British Columbia, Canada
Authors: Yunker Mark B , Cretney Walter J
Published: March 2010

Synchronous samples of sediment and Dungeness crab (Cancer magister) hepatopancreas, which were obtained for monitoring and assessment purposes at British Columbia, Canada, marine pulp mill sites between 1990 and 1995, were used to calculate biota-sediment accumulation factors (BSAFs) for individual chlorinated dibenzo-p -dioxin and dibenzofuran congeners (PCDD/Fs). The BSAFs for individual pairs of samples were highly variable, and no systematic trends were apparent in the observed accumulation factors over time, with crab size, with crab lipid concentration, with sediment percent organic carbon, or among mill sites or depositional environments. Composition and source differences in sedimentary PCDD/Fs, which are apparent as principal components analysis class separations in the sediment data set, also did not correlate with differences in BSAFs. This independence from environmental factors provides a valuable endorsement of the BASF concept for the formulation of aquatic effects-based sediment-quality criteria and human risk-assessment guidelines. However, BSAF values did exhibit a significant, nonlinear decrease with increasing log Kow and with sediment and crab PCDD/F concentrations. The correlation between BSAFs and sediment concentrations accounts for between 14 and 81% of the variability in the BSAF values. The PCDD/F congeners that are present in low concentrations and/or have reduced bioavailability are the congeners that have the strongest correlations between the BSAFs and the sediment PCDD/F concentrations. Congeners that are bioavailable to Dungeness crab exhibit poorer correlations between the BSAFs and sediment concentrations.
Weight loss and net abnormalities ofHydropsyche betteni(caddisfly) larvae exposed to aqueous zinc
Authors: Balch Gordon C , Evans R Douglas , Welbourn Pamela , Prairie Robert
Published: March 2010

Caddisfly larvae (Hydropsyche betteni) were collected near a zinc mining operation and exposed to elevated concentrations of zinc in an attempt to determine the efficacy of using weight change and capture net architecture for assessing the toxicological impact of metal exposure. One group of larvae was collected near the mine site (Adjacent) with another collected upstream and away from the mine (Remote). Weight change and capture net architecture was monitored on 400 individually identifiable larvae. The threshold-observed-effect concentration after 13 d was 7.6 mg/L for the Remote group and 30.2 mg/L for the Adjacent group. After 48 d, the highest test concentration of 42 mg/L resulted in a 23 and 19% loss in live-body weight in the Remote and Adjacent groups, respectively, while control larvae from both groups gained 6% in comparison to initial pre-exposure weights. Five weeks of exposure at 22 mg Zn/L or greater was required by both larval groups to statistically reduce the frequency of normal nets, indicating that the sensitivity of the net response was less sensitive than weight loss. Relative differences in weight changes and net architecture strongly suggest that the Adjacent larval group was slightly more tolerant than the Remote and that this increased tolerance may be related to chronic pre-exposure to zinc prior to collection of larvae. This study demonstrates the utility of using weight loss, net architecture, and tissue burdens for assessing the impact of elevated zinc.
Hepatic P4501A activity, plasma sex steroids, and gonadal steroidogenesis in vitro in yellow perch exposed to 3, 3′, 4, 4′, 5-pentachlorobiphenyl
Authors: Dabrowska Henryka , Fisher Susan W , Ciereszko Renata , Dabrowski Konrad , Woodin Bruce R , Stegeman John J
Published: March 2010

Yellow perch were given a single intraperitoneal injection of polychlorinated biphenyl (PCB) 126 dissolved in cornoil at nominal concentrations of 0, 10, 100, and 500 μg/kg body weight. Following the injection, the fish were held for four weeks under photothermal conditions characteristic for Ohio, USA, and fed a commercial fish food. Thereafter, they were sacrificed to examine the PCB 126 concentrations in the liver and to assess the contaminant effects on hepatic P4501A activity, reproductive hormones in plasma, and steroidogenic potential of gonads. The administered doses resulted in liver concentrations of 0.8 (corn oil control), 12.1, 38.9, and 174.5 μg/kg wet tissue weight. Hepatic P4501A indices were differentially affected depending on both the PCB 126 dose and fish gender. In untreated fish, the P4501A protein and ethoxyresorufin-O -deethylase activity were several times lower in females than in males. In treated males, the hepatic P4501A was inhibited by all three PCB 126 doses. In females, a significant P4501A induction occurred in those dosed with 10 μg/kg, while no changes were found in the two higher-dosed female groups in comparison to controls. A significant negative correlation was observed between hepatic P4501A indices and gonad somatic indexes values and plasma estradiol concentrations. The PCB 126 administration produced alterations in concentrations of plasma sex hormones in females but not in males. The in vitro steroidogenic potential of the female and male gonads was not affected by the in vivo PCB 126 treatment.
Relationships between acute sediment toxicity in laboratory tests and abundance and diversity of benthic infauna in marine sediments: A review
Authors: Long Edward R , Hong Carolyn B , Severn Corinne G
Published: March 2010

Autesedimenttoxicity testshave become important in regulatory, monitoring, and scientificprograms, partly because it has been assumed that they are indicative of ecological damage to benthic infaunal resources. Data from tests of sediment toxicity and measures of benthic community structure were examined from > 1,400 saltwater samples to determine the relationships between acute toxicity and changes in the abundance and diversity of infauna resources. Data were compiled from studies conducted along portions of the Atlantic, Gulf of Mexico, and Pacific coasts of the United States. There was considerable variability among the data sets in the relationships between laboratory results and benthic measures. However, in 92% of the samples classified as toxic, at least one measure of benthic diversity or abundance was <50% of the average reference value. In 67% of these samples, at least one measure of benthic infauna abundance or diversity was <10% of average reference conditions. No amphipods were found in 39% of samples that were classified as toxic, whereas amphipods were absent from 28% of the nontoxic samples. In many survey areas, the abundance of crustaceans (notably the amphipods) decreased in the infauna as amphipod survival decreased in the laboratory tests. There appeared to be a break point in the data indicating that, generally, amphipod abundance in the field was lowest when survival in the laboratory tests dropped below 50% of controls. Based on the weight of evidence from all the data analyses, we conclude that ecologically relevant losses in the abundance and diversity of the benthic infauna frequently corresponded with reduced amphipod survival in the laboratory tests.
Use of plants for toxicity assessment of estuarine ecosystems
Authors: Lytle Julia S , Lytle Thomas F
Published: March 2010

Estuarine ecosystems are being rapidly degraded by environmental toxicants from municipal and industrial wastes, agricultural runoff, recreational boating, shipping, and coastal development, ranking them as the most anthropogenically degraded habitat types on earth. Toxicity tests are used to establish links between adverse ecological effects and the toxicity of environmental chemicals. However, most toxicity tests used for regulating the release of chemicals into the environment have used animals as test species, with the erroneous assumption that toxicant levels protective of fish or invertebrates are also protective of plants. Most plant toxicity tests have used terrestrial crop plants, whereas the few aquatic test species used have been primarily freshwater algae. Even though estuarine and marine vascular plants are highly vulnerable to environmental chemicals, phytotoxicity studies using native coastal plants have been limited, and no such studies are required for testing by regulating agencies. The relevance of toxicity tests of estuarine sediments and of wastes entering the estuary should depend on the use of estuarine and marine plant species. This review summarizes toxicity testing of marine plants used in biomonitoring, phytotoxicity, biotransformations of toxicants, bioaccumulation, and phytoremediation. Challenges to marine plant testing are discussed and include developing standard test protocols, identifying species with minimal salinity and toxicant interaction, defining and choosing a suitable sediment for sediment-bound toxicant testing, selecting endpoints with low variability, producing viable seeds, and culturing test plants. Progress in acquiring a suitable database is being made, but at a rate that is inadequate to create the sound, scientific foundation needed for safeguarding our estuarine ecosystems in the near future.