bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioassay of cadmium using a DNA microarray: Genome-wide expression patterns of Saccharomyces cerevisiae response to cadmium
Authors: Momose Yuko , Iwahashi Hitoshi 
Published: March 2010

Abstract
DNA microarray technology enables genome-wide detection of cell response at the transcriptional level. We are planning to make bioassay systems that can detect environmental chemicals to screen for potential bioreactive agents. To develop a DNA microarray for our purposes, the changes in gene expression underlying the yeast stress response to cadmium were analyzed by a microarray of total mRNA. Cadmium is a potent cell poison known to cause oxidative stress by changing intracellular glutathione levels. We report here that not only the glutathione synthesis gene (GSH1) but also almost all transcripts of the enzymes involved in the sulfur amino acid metabolism, especially MET14 and MET17, were greatly induced after exposure to cadmium. While several common stress-responsive genes, such as HSP26, GRE1, HSP12, and DDR48, were up-regulated more than almost fourfold by cadmium, there were also 42 other genes up-regulated more than fourfold. Based on these results, we concluded that DNA microarrays are very useful instruments for creating new bioassay systems and finding genetic promoters of stress indicators.
Disposition and depuration of lindane (γ-HCH) and polychlorinated biphenyl-110 (2,3,3′,4′,6-pentachlorobiphenyl) in cod (Gadus morhua) and bullrout (Myoxocephalus scorpius) after single oral exposures
Authors: Ruus Anders , Skaare Janneche Utne , Ingebrigtsen Kristian 
Published: March 2010

Abstract
The disposition and depuration of lindane (γ-hexachlorocyclohexane [HCH]) and polychlorinated biphenyl (PCB)-110 (2,3,3′,4′,6-pentachlorobiphenyl), orally administered to cod (Gadus morhua) and bullrout (Myoxocephalus scorpius), were investigated using whole-body autoradiography, liquid scintillation counting, and gas chromatography with electron-capture detection. Both γ-HCH and PCB-110 were distributed mainly to lipid-rich organs after absorption from the gastrointestinal tract of cod and bullrout. Compared to bullrout liver, the cod liver contained higher concentrations of both compounds, reflecting the distribution of fat in the two species. In both species, the depuration time for γ-HCH was shorter than for PCB-110. Both substances were excreted via bile and urine, largely as water-soluble metabolites. The water-soluble bile metabolites, together with PCB-110 metabolites associated to endogenous macromolecules, strongly indicate that this compound is metabolized in both species.
Biotic ligand model of the acute toxicity of metals. 1. Technical Basis
Authors: Di Toro Dominic M. , Allen Herbert E , Bergman Harold L , Meyer Joseph S , Paquin Paul R , Santore Robert C 
Published: March 2010

AbstractThe biotic ligand model (BLM) of acute metal toxicity to aquatic organisms is based on the idea that mortality occurs when the metal—biotic ligand complex reaches a critical concentration. For fish, the biotic ligand is either known or suspected to be the sodium or calcium channel proteins in the gill surface that regulate the ionic composition of the blood. For other organisms, it is hypothesized that a biotic ligand exists and that mortality can be modeled in a similar way. The biotic ligand interacts with the metal cations in solution. The amount of metal that binds is determined by a competition for metal ions between the biotic ligand and the other aqueous ligands, particularly dissolved organic matter (DOM), and the competition for the biotic ligand between the toxic metal ion and the other metal cations in solution, for example, calcium. The model is a generalization of the free ion activity model that relates toxicity to the concentration of the divalent metal cation. The difference is the presence of competitive binding at the biotic ligand, which models the protective effects of other metal cations, and the direct influence of pH. The model is implemented using the Windermere humic aqueous model (WHAM) model of metal—DOM complexation. It is applied to copper and silver using gill complexation constants reported by R. Playle and coworkers. Initial application is made to the fathead minnow data set reported by R. Erickson and a water effects ratio data set by J. Diamond. The use of the BLM for determining total maximum daily loadings (TMDLs) and for regional risk assessments is discussed within a probabilistic framework. At first glance, it appears that a large amount of data are required for a successful application. However, the use of lognormal probability distributions reduces the required data to a manageable amount.
Biotic ligand model of the acute toxicity of metals. 2. Application to acute copper toxicity in freshwater fish andDaphnia
Authors: Santore Robert C , Di Toro Dominic M , Paquin Paul R , Allen Herbert E , Meyer Joseph S 
Published: March 2010

AbstractThe biotic ligand model (BLM) was developed to explain and predict the effects of water chemistry on the acute toxicity of metals to aquatic organisms. The biotic ligand is defined as a specific receptor within an organism where metal complexation leads to acute toxicity. The BLM is designed to predict metal interactions at the biotic ligand within the context of aqueous metal speciation and competitive binding of protective cations such as calcium. Toxicity is defined as accumulation of metal at the biotic ligand at or above a critical threshold concentration. This modeling framework provides mechanistic explanations for the observed effects of aqueous ligands, such as natural organic matter, and water hardness on metal toxicity. In this paper, the development of a copper version of the BLM is described. The calibrated model is then used to calculate LC50 (the lethal concentration for 50% of test organisms) and is evaluated by comparison with published toxicity data sets for freshwater fish (fathead minnow, Pimephales promelas) and Daphnia.
Effect of sediment toxicity on anaerobic microbial metabolism
Authors: Togna Monica T , Kazumi Junko , Apitz Sabine , Kirtay Victoria , Young Lily Y 
Published: March 2010

Abstract
Mineralization of a readily biodegradable aromatic compound (benzoate) by intrinsic microorganisms in the anoxic sediment was used to quantify the inhibitory effect of heavily contaminated sediment from the Arthur Kill estuary (NY/NJ Harbor system, USA) on the anaerobic metabolism by naturally present bacterial populations. In anoxic microcosms, the effect of varying ratios of contaminated sediment: site water and contaminated sediment: noncontaminated sediment (Flax Pond, Stony Brook, NY, USA) were investigated. In all cases, increasing the ratio of Arthur Kill sediment in the microcosms showed an inhibitory effect on the rate of 14C-benzoate mineralization as measured by the evolution of 14CO2. This inhibitory effect could be alleviated through dilution of the sediment with noncontaminated sediment, resulting in some cases in mineralization rates that were greater by an order of magnitude. The toxicity of the sediment was confirmed by whole-sediment Microtox® bioassay. Analysis of the sediment revealed high (&gt;200 mg/kg) levels of Pb, Cu, Zn, and Cr, suggesting that heavy metals may contribute to overall sediment toxicity.
Atrazine biodegradation to deisopropylatrazine and deethylatrazine in coastal sediments of different land uses
Authors: Aelion C. Marjorie , Mathur Priti P 
Published: March 2010

Abstract
Atrazine, a triazine herbicide widely used in the United States, contributes to surface-water and groundwater contamination, as can deisopropylatrazine (DIA) and deethylatrazine (DEA), two of its microbial degradation products. Production of DIA and DEA by native bacteria in aquatic sediments has not been investigated thoroughly. We assessed atrazine and production of DIA and DEA over time in coastal aquatic sediments associated with different land uses including creeks from an undeveloped preserve and a suburban development, a golf course drainage ditch, and a contaminated commercial harbor. Sediments were incubated in microcosms, spiked with U-14C-atrazine, extracted, and analyzed for 14C in a liquid scintillation counter. Atrazine, DIA, and DEA also were quantified by gas chromatography–mass spectrometry. The amount of 14C recovered varied at each site as a function of the sediment organic carbon content and decreased significantly over time. Both DEA and DIA were measured primarily in the aqueous phase. Transformation was more extensive to DIA than to DEA. The ratio of DIA to atrazine recovered from the undeveloped preserve was as high as 0.13. In contrast, the golf course had limited biotransformation, and had the greatest atrazine recoveries so atrazine, not DEA and DIA, may have a greater impact at this site.
2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in tissue samples from three species in the Denver, Colorado, USA, metropolitan area
Authors: Coady Katherine K , Jones Paul D , Giesy John P 
Published: March 2010

Abstract
The Rocky Mountain Arsenal (RMA), a Superfund site near Denver, Colorado, USA, has a history of various industrial processes that may have led to the release of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs). The PCDDs, PCDFs, and non-ortho- and mono-ortho-substituted PCBs cause a common set of toxic effects that are mediated through the aryl hydrocarbon receptor (AhR). The total AhR-mediated activity of complex mixtures in biota samples from the RMA and surrounding reference areas was determined by both instrumental and bioanalytical techniques. Mean concentrations of bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TCDD-EQ) in carp eggs, owl livers, and kestrel eggs ranged from 0 to 8.5, 17 to 130, and 2.4 to 18 pg/g, respectively. For most samples analyzed, concentrations of TCDD-EQ and instrumentally derived TCDD equivalents (TEQs) were not significantly different. In a few tissue samples, concentrations of TEQs and TCDD-EQs were not equivalent. This can indicate the presence of AhR-active compounds that were not identified or quantified by instrumental techniques or the existence of nonadditive interactions among congeners when samples are analyzed by the bioassay. Overall, mean concentrations of TCDD-EQs in extracts of carp and kestrel eggs were not significantly different between groups of samples collected on and off the RMA, whereas concentrations of TCDD-EQs in several owl livers collected on the RMA were significantly greater than concentrations in owl livers from off the RMA.
A method of estimating multicomponent nonaqueous-phase liquid mass in porous media using aqueous concentration ratios
Authors: Devlin John F , Barbaro Jeff R 
Published: March 2010

Abstract
A simple dissolution model based on Raoult's Law was used to derive a log-linear equation for the estimation of multicomponent nonaqueous-phase liquid (NAPL) mass in porous media. The analysis, referred to here as the ratio mass estimation (RME) method, requires aqueous concentration ratios for two components of the NAPL mixture as well as their pure phase liquid solubilities. Application of the equation using data from a previously reported column experiment, in which 1.22 g of a benzene/toluene NAPL were flushed with water, yielded an estimate of 1.2 g of NAPL. In addition, data from two in situ field column experiments of gasoline dissolution were examined. In those experiments, three ratio pairs, benzene/toluene, ethylbenzene/toluene, and ethylbenzene/benzene, were considered from each cell, and the initial NAPL masses were estimated to be between 39 and 42 kg NAPL, within 30% of the true NAPL masses of 54 kg in each cell. Finally, data from the flushing of a controlled release of chlorinated solvents (chloroform, trichloroethene, and tetrachloroethene) inside a sheet pile cell were examined, and the initial NAPL mass was estimated to within 15% of the true value. The RME analysis is based on several simplifying assumptions and should be used with caution. However, this work shows it to be potentially useful under conditions that might be encountered at sites. The analysis is simple and based on data that are often collected routinely.
Induction of morphological deformities in Chironomus tentans exposed to zinc- and lead-spiked sediments
Authors: Martinez Edward A , Moore Barry C , Schaumloffel John , Dasgupta Nairanjana 
Published: March 2010

Abstract
Laboratory experiments were used to assess morphological responses of Chironomus tentans larvae exposed to three levels of zinc and lead. Chironomus tentans egg masses were placed into triplicate control and metal-spiked aquaria containing the measured concentrations 1,442, 3,383, and 5,562 μg/g Pb dry weight and 1,723, 3,743, and 5,252 μg/g Zn dry weight. Larvae were collected at 10-d intervals after egg masses were placed in aquaria until final emergence. Larvae were screened formouthpart deformities and metal body burdens. Deformities increased with time of exposure in both Zn and Pb tanks. Deformity rates between the three Zn concentrations differed statistically, with low and medium Zn levels containing the highest overall deformity rates of 12%. Deformity rates for larvae held in the Pb aquaria were found to differ significantly. Larvae in the low-Pb tanks had a deformity rate of 9%. Larvae and water from both the Zn and Pb aquaria had increasing metal concentrations with increasing sediment metal concentration. Results demonstrate that Zn and Pb each induce chironomid mouthpart deformities at various concentrations. However, a clear dose-related response was not demonstrated. Our research provides more support for the potential use of chironomid deformities as a tool for the assessment of heavy metal pollution in aquatic systems.
Discrepancy between acute and chronic toxicity induced by imidacloprid and its metabolites in Apis mellifera
Authors: Suchail Séverine , Guez David , Belzunces Luc P 
Published: March 2010

Abstract
Imidaclopridi a systemic nitroguanidine insecticide that belongs to theneonicotinoid family. As an agonist of the acetylcholine receptor, it attacks the insect nervous system and is extremely effective against various sucking and mining pests. Oral acute and chronic toxicity of imidacloprid and its main metabolites (5-hydroxyimidacloprid, 4,5-dihydroxyimidacloprid, desnitroimidacloprid, 6-chloronicotinic acid, olefin, and urea derivative) were investigated in Apis mellifera. Acute intoxication by imidacloprid or its metabolites resulted in the rapid appearance of neurotoxicity symptoms, such as hyperresponsiveness, hyperactivity, and trembling and led to hyporesponsiveness and hypoactivity. For acute toxicity tests, bees were treated with doses of toxic compounds ranging from 1 to 1,000 ng/bee (10–10,000 μg/kg). Acute toxicity (LD50) values of imidacloprid were about 60 ng/bee (600 μg/kg) at 48 h and about 40 ng/bee (400 μg/kg) at 72 and 96 h. Out of the six imidacloprid metabolites tested, only two (5-hydroxyimidacloprid and olefin) exhibited a toxicity close to that of imidacloprid. Olefin LD50 values were lower than those of imidacloprid. The 5-hydroxyimidacloprid showed a lower toxicity than imidacloprid with a LD50 four to six times higher than that of imidacloprid. Urea also appeared as a compound of nonnegligible toxicity by eliciting close to 40% mortality at 1,000 ng/bee (10,000 μg/kg). However, no significant toxicity was observed with 4,5-dihydroxyimidacloprid, 6-chloronicotinic acid, and desnitroimidacloprid in the range of doses tested. To test chronic toxicity, worker bees were fed sucrose solutions containing 0.1, 1, and 10 μg/L of imidacloprid and its metabolites for 10 d. Fifty percent mortality was reached at approximately 8 d. Hence, considering that sucrose syrup was consumed at the mean rate of 12 μl/d and per bee, after an 8-d period the cumulated doses were approximately 0.01, 0.1, and 1 ng/bee (0.1, 1, and 10 μg/kg). Thus, all tested compounds were toxic at doses 30 to 3,000 (olefin), 60 to 6,000 (imidacloprid), 200 to 20,000 (5-OH-imidacloprid), and &gt;1,000 to 100,000 (remaining metabolites) times lower than those required to produce the same effect in acute intoxication studies. For all products tested, bee mortality was induced only 72 h after the onset of intoxication.
Variation in cadmium uptake, feeding rate, and life-history effects in the gastropod Potamopyrgus antipodarum: Linking toxicant effects on individuals to the population level
Authors: Jensen Allan , Forbes Valery E , Parker E. Davis 
Published: March 2010

Abstract
A life-table response experiment was performed to investigate the effects of sediment-bound cadmium on individual life-history traits and feeding rates of four clones of Potamopyrgus antipodarum. Demographic effects were evaluated using a simple two-stage model to estimate population growth rate (λ). Decomposition analysis was performed to investigate the contributions of each of the affected life-history traits to the effects observed on λ, and elasticity analysis was applied to examine the relative sensitivity of λ to changes in each of the life-history traits. Interclonal differences in tolerance to sediment-bound cadmium were statistically significant but were within an order of magnitude. There were no consistent patterns among clones in terms of which individual life-history trait was most or least sensitive to cadmium exposure. The relative performance of clones did not rank consistently across the cadmium gradient and was dependent on which trait was measured. Although λ was most sensitive to changes in survival terms, the effects of cadmium on time to first reproduction and reproductive output were the major causes of reductions in λ. Large percent reductions in some of the individual life-history traits were attenuated at the population level, but very small effects on population growth rate were statistically significant.
Prediction of uptake of copper from solution by lettuce (Lactuca sativa Romance)
Authors: Cheng Tao , Allen Herbert E 
Published: March 2010

Abstract
We studied effects of free copper ion activity and total copper concentration on copper uptake by lettuce from nutrient solution and a model was developed. In ethylenediaminetetraacetic acid and dissolved organic matter treatments, when pH and free copper ion activity were the same, root copper concentration did not change with the total copper concentration. However, at fixed pH and total copper concentration, root copper concentration increased with, and was log-log linearly related to free copper ion activity. Copper uptake by plant roots is affected by free copper ion activity, pH, and the concentration of other competing ions such as Ca2+. Based on the free-ion activity model, we developed a model to predict copper concentrations in lettuce root and shoot. The parameters in this model are the binding constant of lettuce root surface site for copper times the site density, log(nKCu) = 11.29 ± 0.10; for protons, log(KH) = 6.80 ± 0.12; and for calcium, log(KCa) = 8.49 ± 0.30. Copper concentration in lettuce shoot was much lower than that of lettuce root. The translocation coefficient (k) is (2.36 ± 0.37) × 10−2.
Uptake of inorganic chemicals from soil by plant leaves: Regressions of field data
Authors: Efroymson Rebecca A , Sample Bradley E , Suter Glenn W 
Published: March 2010

Abstract
The estimation of chemical concentrations in wildlife foods, such as plant foliage, is often performed for risk assessments at contaminated sites. Regression models and uptake factors for use in estimating the uptake of inorganic elements from soil by above-ground plant tissues were derived in this study. These included models for arsenic, cadmium, copper, lead, mercury, nickel, selenium, and zinc. Models were developed using published data from soil contaminated in the field and were validated using measured concentrations from two contaminated sites. Single-variable regression models of log-transformed concentrations in plants versus log-transformed concentrations in soil are generally recommended over simple uptake factors for use in estimating plant uptake of inorganic contaminants in ecological risk assessments. Multiple regression models with soil concentration and pH as the variables are also recommended for estimating the uptake of four chemicals (cadmium, mercury, selenium, and zinc) by plants. Models for use in screening risk assessments, i.e., the upper 95% prediction limits on the regressions, are recommended to provide conservative estimates of uptake of inorganic chemicals by plants.
Does stress protein induction by copper modify natural toxicity in sponges?
Authors: Agell Gemma , Uriz María-J. , Cebrian Emma , Martí Ruth 
Published: March 2010

AbstractCrambe crambe is a toxic Mediterranean sponge that inhabits the sublittoral rocky bottoms, including some contaminated habitats. We investigated whether contamination by copper induced stress proteins in C. crambe and whether such stress might alter the production of chemical defenses. The monoclonal antibody used cross-reacted with two heat shock proteins (HSP) of 54 and 72 kDa. Both proteins were induced to a greater or lesser extent by copper contamination. The HSP54 accumulated more than HSP72, which, in contrast, appeared to respond faster and be less persistent. In a field experiment, we found a higher accumulation of HSP54 in individuals naturally inhabiting a copper-contaminated site than in those transplanted to this site four months earlier. In contrast, HSP72 was significantly induced only in the individuals transplanted to the contaminated site. In the laboratory, both proteins were induced by copper at 30 μg/L but inhibited at 100 μg/L. The highest mean values of HSP54 and HSP72 corresponded to the sponges, which showed the lowest mean values of toxicity. Thus, toxicity and production of HSP displayed opposite trends, which seems to indicate a preferential investment in cell repair at the expense of toxic molecules under stress conditions.
Acute ecotoxicity of creosote-contaminated soils toEisenia fetida: A survival-based approach
Authors: Charrois Jeffrey W A , McGill William B , Froese Kenneth L 
Published: March 2010

AbstractQuantification of risks to the ecosystem is necessary for cost-effective remediation strategies. Contaminant endpoints need to be established that consider the bioavailability of toxicants in soil. The challenge is to develop methods that assign risk to the bioavailable toxic contaminants, thereby protecting ecosystems, while balancing remediation costs. Our objective was to evaluate changes in bioavailability of creosote constituents in soils to earthworms. An acute ecotoxicological investigation of three weathered creosote-contaminated and two slurry-phase-biotreated soils was conducted using a 14-d earthworm (Eisenia fetida) survival bioassay. Soil characterization (physical and chemical) and contaminant concentration data (polycyclic aromatic hydrocarbons [PAH] and total dichloromethane extractable organics [DEO]) were also determined. The toxicity of the soils could not always be predicted based on chemical concentrations alone. Soils having a low PAH:DEO ratio had higher cumulative earthworm survival times as measured by earthworm-days. We propose that the DEO fraction may regulate toxicity by altering bioavailability of toxicants.