bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative sensitivity of life-cycle and biomarker responses in four earthworm species exposed to zinc
Authors: Spurgeon David J , Svendsen Claus , Rimmer Viv R , Hopkin Stephen P , Weeks Jason M
Published: March 2010

Life-cycle (survival, weight change, and cocoon production rate) and biomarker (neutral-red retentionby coelomocytes lysosomes) responses to zinc in four earthworm species were measured in laboratory tests. In all species, dose-dependent effects on survival, cocoon production, and neutral-red retention times were found (one-way ANOVA p < 0.05). However, for weight change, only Aporrectodea caliginosa showed a clear response. Comparisons of the effects of zinc on these parameters in the different earthworm species indicated similar order of sensitivity. Thus, Lumbricus rubellus and Aporrectodea caliginosa were more sensitive to zinc than Lumbricus terrestris and Eisenia fetida in all cases. To compare the relative sensitivities of life-cycle and biomarker responses, a sublethal sensitivity index (SSI) was applied. For cocoon production, SSIs indicated that the EC10s were below LC50s by a factor of between 8.3 and 16.5. These values are toward the high end of the range found previously for soil invertebrates, indicating an emphasis on maximizing survival. For neutral red, SSIs ranged from 4.5 to 41.2. Thus, the biomarker was predictive of life-cycle effects in some (Lumbricus rubellus and Aporrectodea caliginosa), although not the other two species tested.
Effects of weathering on the toxicity of three offshore australian crude oils and a diesel fuel to marine animals
Authors: Neff Jerry M , Ostazeski Stanley , Gardiner William , Stejskal Iva
Published: March 2010

The evaporative weathering properties, chemical composition, and toxicity of three Australian Northwest Shelf crude oils and an Australian diesel fuel were evaluated. The crude oils include one each of a condensate, a light, and a medium crude oil. Between 23 and 100% of the mass of the oils is lost during evaporative weathering equivalent to about 1 week on the sea surface. During weathering, the oils lose most of their monocyclic aromatic hydrocarbons (MAHs) and phenols; concentrations increase of less volatile phenols and polycyclic aromatic hydrocarbons (PAHs). The acute toxicity of water-accommodated fractions (WAFs) of the fresh and weathered oils to six species of temperate and tropical marine animals ranges from > 100% to about 11% WAF. The MAHs are the most important contributors to the acute toxicity of the WAFs of the fresh oils. The contribution of PAHs to WAF toxicity increases with weathering. About 58% of the hazard indices (HI: exposure concentration/acutely toxic concentration) for the WAFs of the two light oils weathered for the equivalent of 1 d are attributable to PAHs. The toxicity of the WAFs of the condensate and light crude oil can be accounted for by MAHs, PAHs, and phenols; WAFs of the middle-weight crude oil and diesel fuel are higher than predicted based on their concentrations of total MAHs, PAHs, and phenols, indicating that other components of the WAFs are contributing to their toxicity. These components may include the unresolved complex mixture and polar compounds (resins).
In vivo comparison of xenoestrogens using rainbow trout vitellogenin induction as a screening system
Authors: Christiansen Lisette B , Pedersen Knud L , Pedersen Søren N. , Korsgaard Bodil , Bjerregaard Poul
Published: March 2010

Vitellogenin induction in rainbow trout after intraperitoneal injection of test compounds was investigated. Vitellogenin quantification was performed by a direct sandwich enzyme-linked immunosorbant assay (ELISA) based on polyclonal, affinity purified antibodies. The system was used as a short-term in vivo screen for estrogenicity and as a tool for establishing the priority of compounds to be tested by water exposure of fish. Representatives from the group of xenoestrogens, bisphenols, phthalates, and pesticides were tested. The relative potency order bisphenol A > bisphenol A dimethacrylate, o,p′-DDT > butylbenzylphthalate was established, while no significant vitellogenin response was seen with dibutylphthalate, tetrabromobisphenol A, and methoxychlor. Of these, tetrabromobisphenol A has not previously been tested for estrogenicity in vivo. Earlier findings of diminished estrogenic activity of ortho-substituted compounds was extended to bisphenols since ortho-bromination of bisphenol A abolished the activity of the parent molecule.
Physiological measures of neurotoxicity of diazinon and malathion to larval rainbow trout (Oncorhynchus mykiss) and their correlation with behavioral measures
Authors: Beauvais Sheryl L , Jones Susan B , Brewer Sandra K , Little Edward E
Published: March 2010

Relations between neurotoxicants and changes in physiological parameters and behavior were investigated in larval rainbow trout (RBT; Oncorhynchus mykiss) exposed to sublethal concentrations of two organophosphate pesticides (OPs). Fish were exposed to diazinon and malathion in static-renewal experiments. After exposures for 24, 96, or 96 h, followed by 48 h of recovery, individual RBT were videotaped to assess locomotory behaviors. Brain tissue from the same fish was assayed for the physiological endpoints, cholinesterase (ChE) activity, muscarinic cholinergic receptor (MChR) number (Bmax), and MChR affinity (KD). Cholinesterase activity decreased significantly with increasing concentrations of both diazinon and malathion and differed significantly among exposure durations, with 24- and 96-h means less than 48-h recovery means. Decreases in Bmax with OP concentration were not significant for either chemical, and KD was unaffected. Changes in swimming speed and distance were significantly correlated with changes in ChE activity for both chemicals; rate of turning was significantly correlated with ChE activity in malathion exposures. These results suggest that correlations between physiological and behavioral changes previously seen in mammals also occur in fish.
Comparison of Chironomus riparius Meigen and Chironomus tentans Fabricius (Diptera: Chironomidae) for assessing the toxicity of sediments
Authors: Watts Matthew M , Pascoe David
Published: March 2010

The benthic macroinvertebrates Chironomus riparius Meigen and C. tentans Fabricius were compared to evaluate their role in the assessment of sediment toxicity. Larval growth and adult emergence of both species were used to assess the toxicity of two sediments, one natural and one artificial, spiked with either cadmium or lindane (i.e., γ-hexachlorocyclohexane). Both toxicants significantly reduced (p < 0.05) larval growth and survival in relation to control animals, with C. tentans being the more sensitive species. Cadmium spiking had no effect on the number of adults that emerged for either species, but emergence times were delayed at the highest cadmium concentration. In contrast, lindane spiking produced a significant reduction (p < 0.05) in adult numbers in relation to control animals, whereas emergence times were not affected. In both the growth and emergence tests, toxicity differed depending on the choice of species and the sediment type. In terms of comparative sensitivity, C. tentans was not only more susceptible to both toxicants but seemed to be less physically robust than C. riparius, leading to some variable data, especially in the emergence study.
Gonadal development and endocrine responses in Japanese medaka (Oryzias latipes) exposed too,p′-DDT in water or through maternal transfer
Authors: Metcalfe Tracy L , Metcalfe Chris D , Kiparissis Yiannis , Niimi Arthur J , Foran Christine M , Benson William H
Published: March 2010

Various isomers and metabolites of DDT disrupt endocrine systems and gonadal development in fish and wildlife, and o,p′-DDT has been shown to be an relatively potent estrogen agonist. In this study, we exposed Japanese medaka (Oryzias latipes) to o,p′-DDT using two exposure protocols: direct exposure of early life stages to aqueous solutions from 1 to 100 d posthatch and exposure of female medaka to aqueous solutions, followed by mating with unexposed males to produce offspring that were exposed through mechanisms of maternal transfer. In treatments with direct aqueous exposures, an intersex condition of the gonad (testis-ova) was observed in male medaka exposed at early life stages to nominal o,p′-DDT concentrations of 50, 10, and 5 μg/L, indicating that this estrogen agonist can alter gonadal development when exposure occurs continuously over the period of gonadal differentiation. Comparisons with previously published data on the induction of testis–ova by exposure to nonylphenol (NP) and octylphenol (OP) indicated that the relative potencies for induction of intersex in medaka are o,p′-DDT > NP ≈︁ OP, which is not consistent with the relative estrogenic potencies of OP > NP > o,p′-DDT observed in the yeast estrogen screening (YES) assay. In the maternal transfer protocol, no testis-ova were observed in the offspring, although there was some delay in time to hatch of the offspring. Medaka exposed by maternal transfer showed no other toxicological responses during early life stages, but when treated fish reached sexual maturity, the females showed more advanced development of oocytes. In addition, when medaka exposed by maternal transfer were subsequently exposed at 10 months of age to 17β-estradiol (12 mg/L), there was a significantly greater induction of hepatic vitellogenin in DDT-exposed males in comparison to control males, indicating that exposure to estrogenic chemicals during early life stages may potentiate vitellogenin induction following exposure events later in the life of the fish.
Characteristics of imidacloprid toxicity in two Apis mellifera subspecies
Authors: Suchail Séverine , Guez David , Belzunces Luc P
Published: March 2010

Imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine) belongs to a new chemical family of chloronicotinyl compounds whose mode of action on the insect nervous system differs from that of traditional neurotoxic products. Imidacloprid, a strong systemic compound, is effective against several sucking and mining pests. The acute toxicity of contact and oral applications on two Apis mellifera subspecies, Apis mellifera mellifera and Apis mellifera caucasica, was investigated. In all toxicological studies, each dose included three cages of 20 individuals and each study was replicated three times. The dose-mortality relation revealed some unusual characteristics. At low imidacloprid concentrations, a biphasic mortality appeared, particularly with the contact exposure route. At moderate doses, mortality profiles at 24 and 48 h were different only after oral application. Response kinetics showed that mortality was delayed at the higher doses of imidacloprid. After oral intoxication, the LD50 values of imidacloprid at 24 and 48 h were about 5 ng/bee for both A. m. mellifera and A. m. caucasica. After contact application, the LD50 values at 24 and 48 h were approximately 24 ng/bee for A. m. mellifera and 14 ng/bee for A. m. caucasica. Imidacloprid ranks among the more potent contact insecticides in this important pollinator species.
Technical basis for narcotic chemicals and polycyclic aromatic hydrocarbon criteria. I. Water and tissue
Authors: Di Toro Dominic M. , McGrath Joy A , Hansen David J
Published: March 2010

A method is presented for developing water quality criteria (WQC) for type I narcotic chemicals in general and PAHs in particular. The criteria can be applied to any individual or mixture of narcotic chemicals using only the chemical's octanol-water partition coefficient KOW. It is derived from a database of LC50s comprising 156 chemicals and 33 species, including fish, amphibians, arthropods, mollusks, polychaetes, coelenterates, and protozoans. A target lipid model is proposed that accounts for variations in toxicity due to differing species sensitivities and chemical differences. The model is based on the idea that a target lipid is the site of action in the organism. Further, it is assumed that target lipid has the same lipid-octanol linear free energy relationship for all species. This implies that the slope of the log(LC50)–log(KOW) relationship is the same for all species. However, individual species may have varying target lipid body burdens that cause toxicity. The target lipid LC50 body burdens derived from concentration data in the water only are compared to measured total lipid LC50 body burdens for five species. They are essentially equal, indicating that the target lipid concentration is equal to the total extracted lipid concentration. The precise relationship between partitioning in target lipid and octanol is established. The species-specific body burdens are used to determine the WQC final acute value, i.e., the 95-percentile level of protection. An acute-to-chronic ratio is used to compute the body burden corresponding to the WQC final chronic value, which is the procedure used to derive the U.S. Environmental Protection Agency water quality criteria. The criteria are expressed either as dissolved concentrations in the water column or as tissue concentrations.
Technical basis for narcotic chemicals and polycyclic aromatic hydrocarbon criteria. II. Mixtures and sediments
Authors: Di Toro Dominic M. , McGrath Joy A
Published: March 2010

Abstract—A method is presented for developing sediment quality guidelines (SQG) for narcotic chemicals in general and polycyclic aromatic hydrocarbons (PAHs) in particular. The guidelines can be applied to any individual or mixture of narcotic chemicals including PAHs using only the chemical's octanol/water partition coefficient. They are derived using the final chronic values for type I narcotics developed from a database consisting of LC50s for 145 chemicals and 33 species, including fish, amphibians, arthropods, mollusks, polychaetes, coelenterates, and protozoans. The target lipid model is used that accounts for the variations in toxicity due to differing species sensitivities as well as chemical differences. The SQGs are derived using the equilibrium partitioning model (EqP), and the results are compared to other sediment quality guidelines. The criterion for a mixture of PAHs is based on the known additivity of narcotic chemicals. The toxic unit concentration corrected for solubility is calculated for each chemical in the mixture and then summed. A total toxic unit greater than one indicates a toxic mixture. The prediction is compared to the results from an experiment using sediment spiked singly and with a mixture of PAHs. The toxicity and amphipod abundance of field-collected sediments are also examined.
Behavior of anionic and nonionic surfactants and their persistent metabolites in the Venice Lagoon, Italy
Authors: Marcomini Antonio , Pojana Giulio , Sfriso Adriano , Alonso José-Maria Quiroga
Published: March 2010

The occurrence and behavior of the aromatic surfactants linear alkylbenzene sulphonates (LAS) andnonylphenol polyethoxylates (NPE) as well as their biotransformation products in the central lagoon of Venice, Italy, were investigated by monitoring deep- and shallow-water lagoon stations, two riverine sites, and one sea station. Additional samplings were conducted at the three inlets connecting the lagoon with the open sea under both ebb and low-tide conditions, and a radiometrically dated sediment core spanning the last century was examined. The spatial distributions of LAS, NPE, and their carboxylic metabolites sulphophenyl carboxylates and nonylphenol carboxylates, respectively, appeared to be rather homogeneous over the entire central lagoon. Remarkable seasonal differences were found, however, primarily because of the increased biodegradation at temperatures greater than 20°C. The estimated primary and ultimate biodegradations of LAS in the lagoon waters were approximately 90 and 72%, respectively. Analysis of the dated sediment core showed similar annual fluxes of both LAS and NPE (48 ng/cm2 year), which were between previously reported values of polychlorinated biphenyls (4.7 ng/cm2 year) and polycyclic aromatic hydrocarbons (167 ng/cm2 year).
Cytochrome P4501A induction potencies of polycyclic aromatic hydrocarbons in a fish hepatoma cell line: Demonstration of additive interactions
Authors: Fent Karl , Bätscher Roger
Published: March 2010

The relative CYP1A induction potencies, determined as ethoxyresorufin-O-deethylase (EROD) activity, and the cytotoxicities of 19 compounds with one to six benzene rings, mixtures of polycyclic aromatic hydrocarbons (PAHs), and contaminated landfill leachates have been determined in the permanent fish hepatoma cell line PLHC-1. No CYP1A induction was observed with benzene, naphthalene, anthracene, acenaphthene, benzo[g,h,i]perylene, and fluorene and low induction was found with fluoranthene and phenanthrene. All other PAHs with three and more benzene rings led to a concentration-related induction of CYP1A, with rebound decreases at high concentrations resulting in bell-shaped concentration–activity curves. Fish-related induction equivalency factors (IEFs) were estimated for all PAHs on the basis of EC50 values of their EROD activities and are reported here for the first time. The following order of decreasing IEFs was found: dibenz[a,h]anthracene > dibenzo[a,i]pyrene > benzo[k]fluoranthene > 3-methylcholanthrene > benzo[a]pyrene > benzo[e]pyrene > chrysene > 7,12-dimethylbenz[a]anthracene > perylene > benz[a]anthracene > pyrene. In contrast to the EROD activity, the immunodetectable protein content determined by ELISA showed a concentration-dependent increase. The interaction of PAHs in mixtures of up to eight individual compounds was additive based on their EROD activities. In landfill leachates, determined induction equivalents (IEQ) were significantly higher than calculated IEQs based on analytical measurements, which indicates additional unknown inducing compounds present in leachates. This study shows that the PLHC-1 cell in vitro system serves as an integrative bioanalytical tool in the ecotoxicological evaluation of aquatic environmental samples contaminated with CYP1A-inducing compounds.
Soil contamination and bioaccumulation of inorganics on petrochemical sites
Authors: Schroder Jackie L , Basta Nicholas T , Lochmiller Robert L , Rafferty Dan P , Payton Mark , Kim Soochong , Qualls Charles W
Published: March 2010

Petrochemical waste contains inorganic contaminants that can pollute soil and pose ecological risks to wildlife. Few studies have evaluated bioaccumulation of inorganic contaminants by small mammals from soil contaminated with petrochemical waste. In this study, we determined the extent of soil contamination with inorganics, the bioaccumulation of metals and F in bone of cotton rats (Sigmodon hispidus), and the relationship between contaminants in soil and in bone of cotton rats on petrochemical waste sites. Cotton rats and soils from 12 petrochemical-contaminated and matched reference sites were analyzed over a three-year period. The number of petrochemical-contaminated sites with soil contamination (in parentheses) were Zn (12), Pb (9), Cr (9), Cu (8), F (7), Ni (7), Sr (6), Ti (5), V (5), Co (3), Ba (3), and Cd (2). Lead and F were the most frequently bioaccumulated contaminants in cotton rat bones. Bone Pb of 3.8 to 63.4 mg/kg was 2- to 42-fold and bone F of 830 to 3,680 mg/kg was 5- to 23-fold greater than mean bone Pb and F from reference sites. Bone Pb and F showed a seasonal trend with winter greater than summer levels. Bone F was an accurate predictor of dental fluorosis when bone F was low (< 1,000 mg/kg, no fluorosis) or high (>3,000 mg/kg, fluorosis) but was inaccurate for intermediate bone F (1,000–3,000 mg/kg). The prevalence of dental fluorosis on F-contaminated sites was 50% higher in winter than summer. Strong relationships were found between bone F and HCl-extractable F (r = 0.70) and bone F and total content of F (r = 0.85) in F-contaminated soils. Land disposal of petrochemical wastes should limit the amount of inorganic contaminants applied to soil.
Metabolic response of Lumbriculus variegatus to respiratory uncoupler in cold and anoxic water
Authors: Penttinen Olli-Pekka , Kukkonen Jussi V K
Published: March 2010

A direct calorimetry approach was applied to compare physiological interaction of pentachlorophenol (PCP) with the energy metabolism under anoxia and normoxia in the aquatic oligochaete worm Lumbriculus variegatus. In normoxia, heat dissipation begins to accelerate 10 h after the onset of PCP exposure until it settles at a new plateau level, and shows a twofold increase from the nonimpact rate. In anoxia, heat output was suppressed down to a level of ∼18% (7°C) of normoxia. An anoxic PCP exposure did not produce any notable changes in the heat output, and the amount of chemical accumulated in tissues was only a fraction (18%) of that accumulated in normoxia. Whether the inhibition of the physiological response during anoxia was due to a shift to anaerobic metabolism or to reduced accumulation in tissues, or combination of both factors, was unclear.
Transport and fate of organochlorines discharged to the salt marsh at Upper Newport Bay, California, USA
Authors: Masters Patricia M , Inman Douglas L
Published: March 2010

Despite long-term monitoring of water quality in the coastal lagoons of California, USA, the fate of organochlorines discharged from agricultural and urban sources to salt marsh habitats has received little attention. We measured organochlorine concentrations in Upper Newport Bay marsh and channel sediments and salt marsh plants. Sediment grain-size analyses show that organochlorines are fractionated and concentrated in the organic material traveling with the clay fraction of the washload discharged into the bay from San Diego Creek. Hydrophobic compounds such as DDT are not associated with the sand and silt fractions. The most frequently detected analyte was p,p′-1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE), occurring in 100% of the sediment samples and 87% of the plant root samples. Maximum concentrations in sediment were 122 ng/g (dry wt) for DDE and 162 ng/g DDT plus metabolites (∑DDT) in salt marsh deposited since 1980. Ratios of DDT to its metabolites suggest that anaerobic degradation of DDT occurs in the cordgrass (Spartina foliosa Trin.) sediments. Cordgrass and pickleweed (Salicornia virginica L.) partition organochlorine residues to the root epidermis, attaining values of 50,000 ng/g lipid for ∑DDT and 80,000 ng/g lipid for heptachlorepoxide (1,4,5,6,7,8,8-heptachloro-2,3-epoxy-3α,4,7,7α-tetrahydro-4,7-methanoindan).
Genetic diversity ofClethrionomys glareoluspopulations from highly contaminated sites in the Chornobyl region, Ukraine
Authors: Matson Cole W , Rodgers Brenda E , Chesser Ronald K , Baker Robert J
Published: March 2010

At radioactive sites, at least two mechanisms may affect the genetic diversity of populations of a given species. Increased mutation rates due to radiation exposure may increase the amount of genetic diversity in a population. Alternatively, population bottlenecks exacerbated by environmental degradation may lead to a reduction of diversity. The relationship between these two contradictory forces is complex. To explore this relationship, long-term monitoring of a genetic marker within a population is needed. To provide baseline data on the population genetics of the bank vole (Clethrionomys glareolus) living in the most contaminated regions at Chornobyl, Ukraine, we have sequenced 291 base pairs of the mitochondrial DNA control region. Bank voles were chosen as a model system because they have the highest levels of internal dose of cesium-134, cesium-137, and strontium-90 within the Chornobyl exclusion zone. We sampled three geographic sites, which were Oranoe, a reference site with virtually no radioactive contamination (<2 Ci/km2), and two highly contaminated sites, Glyboke Lake and the Red Forest (both 1,000 Ci/km2). Genetic diversity in the population from Red Forest (0.722 ± 0.024) was significantly greater than at the Oranoe reference site (0.615 ± 0.039), while genetic diversity at Glyboke Lake (0.677 ± 0.068) was intermediate. It is concluded that long-term studies of historical and demographic characteristics for experimental and reference populations are required in order to employ population genetics to understand the biological impact of environmental contaminants on the genetics of natural populations.
Effects of sorption on the biodegradation of 2-methylpyridine in aqueous suspensions of reference clay minerals
Authors: O'Loughlin Edward J , Traina Samuel J , Sims Gerald K
Published: March 2010

The effects of sorption on the bioavailability of 2-methylpyridine (2-MP) were investigated by determining the biodegradation of 2-MP by an Arthrobacter sp. in aqueous suspensions of reference clay minerals and a synthetic cation exchange resin. Adsorption of 2-MP on kaolinite, illite, hectorite, montmorillonite, and Dowex® was determined by the batch equilibrium method. In general, adsorption of 2-MP was positively correlated with the cation exchange capacity of the sorbent, suggesting that sorption of 2-MP on clay minerals occurs through a cation exchange reaction via the 2-methylpyridinium ion. The biodegradation of 2-MP was most rapid in the kaolinite suspensions, followed by no clay > illite ≫ Dowex > hectorite/montmorillonite. With the exception of kaolinite, adsorption of 2-MP on clay minerals and Dowex reduced the rate of biodegradation. The degree of attenuation was positively correlated with the fraction of 2-MP sorbed, suggesting that sorbed 2-MP was not directly available for degradation. Desorption was not rate limiting in suspensions containing hectorite, montmorillonite, or Dowex; however, desorption may have become limiting in the kaolinite and illite suspensions. The results of this study clearly indicate that adsorption can directly affect the degradation of 2-MP in complex mineral systems.
Steady-state concentrations of carbonate radicals in field waters
Authors: Huang Jiping , Mabury Scott A
Published: March 2010

The carbonate radical [•CO−3] is a secondary radical that results from the scavenging of hydroxyl radical (•OH) by carbonate/bicarbonate. N,N-dimethylaniline was found to be a selective probe for measuring the steady-state concentration of this radical in a variety of natural waters. The pH, nitrate, total carbonate/bicarbonate, and dissolved organic carbon (DOC) in selected field waters were quantitatively analyzed. It was assumed that hydroxyl radicals were produced primarily from the slow photolysis of nitrate and DOC and then were scavenged by carbonate/bicarbonate that were competing with DOC. Steady-state carbonate radical concentrations [•CO−3]ss in natural waters were measured by irradiating solutions of natural waters containing N,N-dimethylaniline in a photoreactor with varying intensity as well as using natural sunlight. The measured steady-state concentration of carbonate radicals was found to be strongly dependent on light intensity and ranged from 5 × 10−15 to 10−13 M. Further kinetic analysis of the data showed that carbonate radical concentrations were related to the concentrations of nitrate and dissolved organic carbon in natural waters through a simple linear relationship.
Quality-assurance study of marine lipid-class determination using chromarod/iatroscan® thin-layer chromatography-flame ionization detector
Authors: Bergen Barbara J. , Quinn James G , Parrish Christopher C
Published: March 2010

An Iatroscan® thin-layer chromatography–flame ionization detector has been utilized to quantify lipid classes in marine samples. This method was evaluated relative to established quality-assurance (QA) procedures used for the gas chromatographic analysis of PCBs. A method for extracting and analyzing eight major lipid classes in the ribbed mussel (Guekensia demissus) was developed. The analytical method met the QA criteria prescribed for consistent external calibrations, low blanks, complete extraction of all lipid classes, and precise replicate analysis. Matrix and blank spikes were satisfactorily recovered (50-130%), provided that the samples contained a large enough mass (>4% dry weight) of total lipids to overcome the absorption of polar lipids on glassware. The use of frozen mussel homogenate as a standard reference material was not possible because of lipid degradation, particularly of triacylglycerols and phospholipids. Also, total lipids measured gravimetrically significantly decreased in frozen samples, which could influence bioaccumulation predictions. A laboratory intercalibration was performed using a mussel homogenate and chloroform extract, which verified the accuracy of the method and the lipid-class identification. Characterizing the structure of one class of polar lipids, the acetone mobile polar lipid (AMPL), showed that it contained no ester linkages or free/sterically unhindered -OH groups; however, the AMPL did contain an ether linkage.
Effect of mass-transfer limitations on bioavailability of sorbed naphthalene in synthetic model soil matrices
Authors: Mulder Hendricus , Breure Anton M , van Andel Johan G , Grotenhuis J Tim C. , Rulkens Wim H
Published: March 2010

External and internal mass-transfer resistances influencing the bioavailability of sorbed naphthalene in a synthetic model matrix for soil aggregates were investigated in batch experiments in mixed reactors. Amberlite® adsorption resins (XAD4 and XAD7) were used as the synthetic model for soil aggregates. The effect of hydrodynamic conditions in the slurry phase on the diffusive transport across a stagnant film surrounding the model particles was studied. In addition, a mechanistic model was developed based on mass balances, diffusion equations, a nonlinear sorption isotherm, and microbial degradation kinetics. Experimental results could be explained well with this model. In the absence of external transfer limitations, intraparticle effective diffusion coefficients of (3.55 ± 0.10) × 10−9 m2/s and (5.29 ± 0.86) × 10−10 m2/s were determined for naphthalene in Amberlite XAD4 and XAD7, respectively.
Stability and detection of α-pinene oxide in aqueous culture medium
Authors: Kajihara Kimberly K , Amaral John A , Toia Robert F
Published: March 2010

Methane consumption by methanotrophic bacteria was previously shown to be temporarily inhibited by α-pinene. Based on literature considerations, loss of inhibition may be due to bacterial degradation of the monoterpene to α-pinene oxide, an anticipated metabolite. However, since α-pinene oxide is unstable in aqueous media, detection of its production by methanotrophs or other bacteria is problematic. Therefore, we used gas chromatography-mass spectrometry analysis to study the chemical breakdown of α-pinene oxide in various buffer systems (Tris[hydroxymethyl]am inomethane, 3-[N-morpholino]propanesulfonic acid, phosphate; pH 7-9) suitable for bacterial whole-cell and cell-free experiments. In every case, aqueous phase α-pinene oxide was unstable and its disappearance was accompanied by the appearance of five decomposition products in a characteristic fingerprint that was in part buffer dependent. However, this fingerprint was adequately stable in phosphate buffer such that its appearance could be used to infer the intermediacy of α-pinene oxide if produced by the bacteria at or near their optimal pH.
Effects of heavy metals and 3-methylcholanthrene on expression and induction of CYP1A1 and metallothionein levels in trout (Oncorhynchus mykiss) hepatocyte cultures
Authors: Faverney Christine Risso-de , Lafaurie Marc , Girard Jean-Pierre , Rahmani Roger
Published: March 2010

Induction of both CYP1A1 and metallothioneins (MTs) in fish liver is increasingly being used in ecotoxicological studies. The interaction of heavy metals (Cd, Cu, Zn, Pb) with the CYP1A induction response and MT levels was studied in trout (Oncorhynchus mykiss) hepatocyte cultures. Cells were exposed to 3-methylcholanthrene (3-MC) or to increasing heavy metal concentrations or to a mixture of both (3-MC and one heavy metal). Metal cytotoxicity was assessed by the neutral red test. Ranking of toxicity was Cd(II) > Cu(II) > Zn(II) > Pb(II) (EC50: 45, 222, 873, and 945 μM, respectively). CYP1A1 expression was monitored by ethoxyresorufin-O-deethylase (EROD) activity as well as by Western and Northern blots. As expected, 3-MC induced EROD activity in a time- and dose-dependent manner (maximal induction 5 times that of the control at 0.5 μM and after a 72-h exposure period). These data were confirmed by Western blot (intense band of 55–60 KDa) and Northern blot analyses. Induction caused by 0.5 μM 3-MC was reduced to less than 50% of control by the concomitant exposure to Cd, Cu, Pb, or Zn (EC50: from 1 μM for Cd(II) to 18 μM for Pb(II)). The MTs were significantly induced in hepatocytes exposed to heavy metals for 24 h. In the presence of 3-MC (0.5 μM), MT levels were significantly lower than those found in cells treated with metals alone at 24 h only. Our results lead to the conclusion that heavy metals significantly affect CYP expression and that a CYP1A1 inducer (3-MC) can modulate the induction of MTs. These data have to be taken into consideration in biomarker monitoring.
Impact of atrazine on organophosphate insecticide toxicity
Authors: Belden Jason B , Lydy Michael J
Published: March 2010

Acute toxicity of selected organophosphorus insecticides (OPs; chlorpyrifos, methyl parathion, diazinon, and malathion) was determined for individual OPs and binary combinations of the OPs with atrazine to larvae of the midge Chironomus tentans. Atrazine individually was not acutely toxic even at high concentrations (10,000 μg/L); however, the presence of atrazine at much lower concentrations (40–200 μg/L) increased the toxicity of chlorpyrifos, methyl parathion, and diazinon. Atrazine did not increase the toxicity of malathion. Possible mechanisms for the synergistic toxicity found between atrazine and chlorpyrifos were investigated, including increased uptake rate and increased biotransformation into a more toxic metabolite. Although the uptake rate was increased by more than 40%, the resulting increase in toxicity would be minimal as compared to the 400% decrease estimated to occur in EC50 values for the same atrazine exposure (200 μg/L). Body residue analysis of midges exposed in vivo to atrazine and chlorpyrifos mixtures for 96 h indicated that a larger amount of metabolites was generated in atrazine treatments as compared to controls. Additionally, in vitro assays of microsomal proteins obtained from treated and control midges indicated that an increase in toxic metabolite (chlorpyrifos-O-analog) was generated in atrazine-treated midges. Therefore, the increase in toxicity is thought to be due to an increase in biotransformation rates of the OPs, resulting in more O-analog within the organism.
Do genotype responses always converge from lethal to nonlethal toxicant exposure levels? Hypothesis tested using clones of Daphnia magna straus
Authors: Barata Carlos , Baird Donald J , Miñarro Antonio , Soares Amadeu M.V.M
Published: March 2010

This study examines the hypothesis that genotypic differences in tolerance will converge with decreasing levels of toxicity: from lethal to sublethal responses and from high to low sublethal exposure levels of toxic chemicals. Four laboratory Daphnia magna clones and three chemicals with different modes of action and known sublethal effects—cadmium, copper, and fluoranthene—were selected to test the previously mentioned hypothesis. Specifically, we compare how genetic variability in feeding responses among the studied Daphnia clones changed across increasing nonlethal exposure levels (expressed as increased exposure levels of feeding inhibition, EC) and how these changes converge relative to acute lethal responses (expressed in terms of the 48-h LC50). Our data show that cadmium fully supports the convergence hypothesis and that data with fluoranthene may also support it. Nevertheless, the most important findings of the present study are to have provided experimental evidence that (1) lethal responses in acute exposures and sublethal responses such as feeding inhibition are not related, (2) genetic variability for sublethal responses tend to be lower than acute responses, and (3) trade-offs between low and high sublethal exposure levels rather than genetic heterogeneity governed sublethal responses. The first two findings have important implications for risk assessment if further supported with more data on other toxicants and clones since they suggest that concerns voiced about the need to include more genetic variability in chronic toxicity tests may be groundless. The third finding may indicate that selection under low and variable environmental levels of toxicants with sublethal effects of feeding may select genotypes with high phenotypic plasticity in response to toxic stress rather than genotypes that perform well within particular toxicant exposure levels.
Predictability of the toxicity of multiple chemical mixtures to Vibrio fischeri: Mixtures composed of similarly acting chemicals
Authors: Altenburger Rolf , Backhaus Thomas , Boedeker Wolfgang , Faust Michael , Scholze Martin , Grimme L Horst
Published: March 2010

The prediction of combined effects based on the effects of the individual components of mixtures by using the pharmacological concepts of concentration addition and independent action might be a promising tool for the risk assessment of pollutant mixtures. To analyze and compare the predictive capabilities of the reference concepts for similarly acting chemicals, the overall toxicity of a multiple mixture was determined in a bioluminescence inhibition assay with Vibrio fischeri. The mixture was composed of 16 similarly and specifically acting chemicals, anticipated to have a common mode of action via weak acid respiratory uncoupling of oxidative phosphorylation. Results show that the observed mixture toxicity is rather well predicted by both concepts. Concentration addition shows an excellent predictive power; the median effective concentration (EC50) of the mixture is predicted with an error of about 10%. Independent action, in contrast, underestimates the EC50 of the mixture by a factor of a little more than three. With respect to risk assessment procedures, it may be concluded that concentration addition gives a valid estimation of the overall toxicity for multiple mixtures with similar and specific mechanisms of action of the mixture components in this type of biotest.
Using probability of extinction to evaluate the ecological significance of toxicant effects
Authors: Snell Terry W , Serra Manuel
Published: March 2010

A large component of uncertainty in ecological risk assessment (ERA) arises from the disparity between the time scale of toxicity measurements and the time scale of predictions of ERA models. It is difficult to make predictions about the persistence of populations from data from short-term toxicity tests. Reproductive toxicity tests provide data about how population growth rate (r) is reduced with toxicant exposure. Although reduction in r is believed to be one of the most important effects of toxicant exposure, its ecological significance has been difficult to quantify. For rotifers, r is typically reduced by 10 to 15% at no-observed-effect concentrations (NOEC). We investigated r reductions of 0 to 30% in time series models of the dynamics of natural rotifer populations to predict probability of quasiextinction. Computer simulations showed that small reductions in r can have large effects over long time periods. This means that purportedly safe toxicant concentrations like those at NOEC levels can reduce r so that population extinction becomes much more likely. Reductions in r greater than about 30% destine rotifer populations near certain extinction within 100 years. Simulations indicate that an r reduction of 5% (EC5) approximately doubles the probability of extinction and is probably the maximum tolerable for the long-term persistence of rotifer populations. When episodic catastrophic population reductions are coupled with r reduction, probabilities of extinction are increased substantially. Several models yielded similar results, so the conclusions do not seem strongly dependent on the form of the model. Incorporating population viability analysis into ecological risk assessments could improve our ability to define conditions required for the long-term sustainability of populations.
Surfactant sorption to soil and geologic samples with varying mineralogical and chemical properties
Authors: Salloum Myrna J , Dudas Marvin J , McGill William B , Murphy Sean M
Published: March 2010

The sorptive behavior of two surfactants (Triton X-1000® and Dowfax® 8390) with two surface soil samples, a subsurface soil sample, a weathered black shale containing large amounts of aged organic matter, an aeolian sand, and two clay minerals (montmorillonite and kaolinite) was examined. Dowfax 8390 (dianionic surfactant) sorption was not detected with any of the samples. In contrast, Triton X-100, an ethoxylated nonionic surfactant, sorbed to all the samples. The mole surfactant sorbed/g sorbent (mol surf g sorbent) was greater for samples containing large amounts of smectite minerals and nonlinearity of the Triton X-100 isotherm increased in samples low in organic carbon. The X-ray diffraction analysis concluded that the ethoxylate group of Triton X-100 intercalates with montmorillonite. The weathered black shale sample also has a high mol surf g sorbent value when reacted with Triton X-100 but contains less smectite clay. We suggest that Triton X-100 may be reacting via hydrophobic groups (branched alkyl chain) with the shale sample. Consequently, sorption of alcohol ethoxylate surfactants cannot be predicted solely on the basis of soil attributes such as clay or organic matter content, for it appears that the organic matter-clay organization may predominate in these types of interactions.
Importance of the test volume on the lag phase in biodegradation studies
Authors: Ingerslev Flemming , Toräng Lars , Nyholm Niels
Published: March 2010

Increasing the total volume of test medium resulted in decreased lag times (T L) in biodegradability shake flask batch tests conducted with either surface water or with synthetic mineral medium inoculated with supernatant from settled activated sludge. Experiments were performed with test volumes ranging from 1.8 ml to 100 L using two 14C-labeled model chemicals, 2,4-dichlorophenoxyacetic acid (2,4-D) and p-nitrophenol (PNP), both of which are known to be readily degradable after variable lag phases. The TL ranged from 2.1 to 30.4 d for PNP and from 16 to 37 d for 2,4-D. Decreasing the test volume tended to increase the lag time, even when a single test batch was redistributed into smaller flasks. With 5 ml supernatant added to different volumes of mineral medium, lag times for PNP were independent of the test volume in a range from 10 to 1,000 ml. At small volumes of 10 ml or less, degradation failed randomly. Our findings are partly explained by the hypotheses that a sufficient total amount as well as a sufficient concentration of specifically degrading microorganisms or consortia of bacteria must be present initially for biodegradation to get started, from which follows that with too small inoculations or with too small test volumes, biodegradation may fail randomly. A straightforward practical implication of the findings is that the test volume in biodegradability tests can significantly influence the lag time and thus sometimes be decisive for the outcome in biodegradation studies.
Effects of extreme tidal range on characteristics of polychlorinated biphenyl distribution in sediment of industrial Incheon North Harbor, Korea
Authors: Kim Seung K , Lee Dong S , Oh Jae R , Kahng Sung H
Published: March 2010

This study investigated the influence of the high tidal range on the polychlorinated biphenyl (PCB) levels and the compositional characteristics in the sediments of the North Incheon Harbor basin, Korea. The results indicated that the high tidal range could induce complicated effects on the distribution and the compositional characteristics of PCBs. Significant differences in the total PCB concentration were found between the tidal and subtidal zones. Higher total PCBs in the tidal zone established a total PCB gradient in a transversal direction along the harbor basin. The large tidal range created tidal currents strong enough to grade the sediment particles, establishing a gradient of total PCBs corresponding to an observed sediment particle size along the longitudinal direction of the basin. Heterogeneous congener patterns were observed in some parts of the tidal zone where diverse physicochemical and microbiological conditions are to be expected. However, tidally driven, active sediment transport promoted spatial homogeneity in the congener pattern. Sedimentation rate of suspended solids appeared to overwhelm any induced heterogeneity in the PCB congener pattern. Consequently, the congener pattern within the harbor basin was fairly uniform and similar to that of a dominant input source.
Geochemistry and toxicity of aluminum in the saguenay river, québec, Canada, in relation to discharges from an aluminum smelter
Authors: Roy Robert L , Campbell Peter GC , Prémont Stéfane , Labrie Jacques
Published: March 2010

The transformation of bauxite to alumina, the first step in the production of metallic aluminum (Al), generates Al-rich effluents. One installation is located near Jonquière (QC, Canada), with the effluents being discharged into the Saguenay River. We undertook an integrated geochemical and ecotoxicological study to determine if these Al discharges affected the receiving water. In the spring, summer, and autumn of 1997, samples of river water were collected from stations upstream and downstream of the effluent outfalls and from a regional reference site. Samples were analyzed for Al (e.g., particulate and dissolved Al, total monomeric and organic monomeric Al, dissolved polymeric Al) and for parameters known to affect Al speciation (pH, SO4, fluoride, dissolved organic carbon). Parallel samples were used for ambient toxicity tests with fathead minnow and Ceriodaphnia dubia. Concentrations of total Al (231-596 μg/L) and dissolved Al (112-344 μg/L) at downstream stations were 1.1 to 3.7 times higher than those at the station immediately upstream. Average levels of total and dissolved Al exceeded the Québec provincial criterion of 87 (μ acid-recoverable Al/L, even at sites upstream of the plant. Inorganic monomeric Al at downstream stations ranged from 22 to 88 (μ/L. With the exception of a single elevated value observed at one downstream site, inorganic monomeric Al levels were> 75 μg/L. Other studies in soft neutral-pH waters have shown that no toxic effects occur at this concentration of inorganic monomeric Al. None of the river water samples from stations 300 m downstream from the outfalls caused significant toxicity to C. dubia or fathead minnows. We suggest that expressing guidelines as monomeric inorganic Al would offer a more useful basis for comparison with ambient Al concentrations.
Influence of salinity onVibrio fischeriandlux-modifiedPseudomonas fluorescenstoxicity bioassays
Authors: Cook Sonja V , Chu Angus , Goodman Ron H
Published: March 2010

This study compares the toxicological response of the marine bacteria Vibrio fischeri and a lux-modified soil and freshwater bacteria, Pseudomonas fluorescens, to saline contamination alone and in the presence of chromium and phenol. Saline solutions are more toxic to P. fluorescens than V. fischeri, and salinity can stimulate luminescence in V. fischeri. Vibrio fischeri is about 10 times more sensitive than P. fluorescens to chromium and phenol. However, the response of P. fluorescens to these toxicants is sensitive to changes in saline contamination, while the response of V. fischeri is not. Therefore, the P. fluorescens bioassay may be a more appropriate bioassay organism than V. fischeri when evaluating the toxicological impact of salinity within saline environmental samples.