bluuebunny/crossref_metadata_2025_split huggingface dataset:
Essential and desirable characteristics of ecotoxicity quantitative structure–activity relationships
Authors: Schultz T. Wayne , Cronin Mark T. D. 
Published: March 2010

Abstract
Quantitative structure–activity relationships (QSAR) developed and applied in the prediction of ecotoxic potencies far out number those in other areas, such as health effects. There are yet to be any formal guidelines for the development of ecotoxicological QSARs. Despite this, the depth and breadth of our knowledge of QSARs as they apply to ecotoxicology, especially short-term aquatic toxicity, allow for the formulation of characteristics that appear to be essential and/or desirable for high-quality QSARs. The three components of a QSAR are the biological activity, the property/structural descriptors, and the statistical methodology. Problems may arise from all three components and may be compounded by interactions between them. In an effort to minimize any tribulations associated with development and application of ecotoxic QSARs, a number of essential or desirable characteristics have been identified. Ecotoxicological data used in formulating the QSAR must be reliable, of high quality, and reflect a well-defined and continuous endpoint; this dataset should be diverse both in terms of potency and chemical structure (i.e., property). Descriptors used in formulating the QSAR should be of high quality, reproducible, of a number and type consistent with the endpoint being modeled, and when possible allow for a mechanistic interpretation of the QSAR. The statistical process used in formulating a QSAR should be as rigorous as possible, appropriate for the endpoint being modeled, and allow for the development of as easily interpretable (i.e., transparent) QSARs as possible. The resultant QSAR should be validated, only used within the descriptor space and chemical domain of the model, and relied on in relation to the total weight of evidence; precision of the QSAR and expectations from its application need to be related to the error in the original ecotoxicological and descriptor measurements. Finally, development of QSARs should be through the interaction of a group of multidisciplinary experts.
Perfluorooctane sulfonic acid in bib (Trisopterus luscus) and plaice (Pleuronectes platessa) from the Western Scheldt and the Belgian North Sea: Distribution and biochemical effects
Authors: Hoff Philippe T. , Van de Vijver Kristin , Van Dongen Walter , Esmans Eddy L. , Blust Ronny , De Coen Wim M. 
Published: March 2010

Abstract
A biomonitoring campaign was conducted in the Belgian North Sea and in the Western Scheldt (The Netherlands) with the primary goal to assess perfluorooctane sulfonic acid (PFOS) contamination and distribution in different biota. This study covers the results obtained for bib (Trisopterus luscus) and plaice (Pleuronectes platessa) and includes the assessment of some stress-related biochemical endpoints. Analysis of liver and muscle PFOS concentrations of both species provided evidence for the existence of a PFOS pollution gradient along the Western Scheldt with higher levels at the upstream locations and a lower degree of PFOS pollution at the marine locations. Cellular necrosis was studied by measuring aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the serum. Serum ALT but not serum AST was shown to correlate positively with the PFOS liver concentration in bib (r = 0.44, p &lt; 0.05), indicating that PFOS might contribute to the induction of hepatic damage in bib in the area of study. Analysis of total carbohydrate, lipid, and protein content of bib liver tissue revealed a positive correlation between the protein content and the PFOS liver concentration (r = 0.55, p &lt; 0.01). Whether this is due to induction of compensatory mechanisms, detoxification, or repair processes remains unclear.
Biomass growth, micronucleus induction, and antioxidant stress enzyme responses in Vicia faba exposed to cadmium in solution
Authors: Rosa Edson V. Cordova , Valgas Cleidson , Souza-Sierra Maria M. , Corrěa Albertina X. R. , Radetski Claudemir Marcos 
Published: March 2010

Abstract
Biomass growth, micronucleus induction, and antioxidative stress enzymes (superoxide dismutase, peroxidase, glutathione reductase, and catalase) were investigated simultaneously in the Vicia faba plant exposed to cadmium in solution. The biomass lowest-observed-effect concentration (LOEC) value was 2,000 μM Cd2+. In the shoots, enzymic activities increased without concentration–response relationships. In the roots, after an initial increase, activities of all enzymes showed negative concentration-response relationships. A significant increase in micronucleus induction was observed at 20 μM Cd2+. Regarding sensitivity, our results showed that biomass endpoint was less sensitive than micronucleus induction, which was less sensitive than antioxidative enzyme activities. The increase of antioxidant stress enzyme activities in response to cadmium exposure may be taken as evidence for an enhanced detoxification capacity of V. faba plants toward reactive oxygen species (and derivatives) that might be generated in the stressed plants. Concomitant micronucleus induction may be also interpreted as a consequence of oxidative stress, upholding the view that cadmium-induced DNA damage is, to some extent, via generation of reactive (intermediate) oxygen species.
Analysis of monitoring data of pesticide residues in surface waters using partial order ranking theory
Authors: Sørensen Peter B. , Brüggemann Rainer , Carlsen Lars , Mogensen Betty B. , Kreuger Jenny , Pudenz Stefan 
Published: March 2010

Abstract
In this investigation, a new and simple way to analyze, interpret, and generalize monitoring data of occurrence of pesticide active ingredients in surface waters was developed. The occurrence is quantified using the variables frequency of detection and the concentration level. These two parameters are associated with basically different ecotoxicological effects; for example, a high frequency of detection may be related to bioaccumulation problems, while the level of concentration also controls the acute toxicological effects. The active ingredients were ranked on the basis of the monitoring data in relation to both the frequency of finding and concentration level using the concept of partial ordered sets. The resulting rankings was correlated with other rankings based on descriptors such as sprayed area, applied dose, adsorption to soil organic carbon, vapor pressure, and soil dissipation half-life. A similarity index was applied in order to compare the ranking of the monitoring data with the ranking of the descriptors. It is shown how partial order theory can be used to evaluate the relevance of every single descriptor. The dosage is found to be the most important descriptor, followed by the sprayed area and the adsorption to organic carbon ending up a very close similarity between, respectively, the rankings using monitoring data and rankings using these three descriptors.
Genetic structure and mtDNA diversity ofFundulus heteroclituspopulations from polycyclic aromatic hydrocarbon-contaminated sites
Authors: Mulvey Margaret , Newman Michael C. , Vogelbein Wolfgang K. , Unger Michael A. , Ownby David R. 
Published: March 2010

AbstractGenetic structure and diversity of mummichog (Fundulus heteroclitus) populations were investigated using mitochondrial DNA (mtDNA) sequences. Forty-six haplotypes were identified among 208 mummichog from the Elizabeth and York Rivers in Virginia, USA. No evidence of decreased gene or nucleotide diversity for mummichog from polycyclic aromatic hydrocarbon (PAH)-contaminated sites was observed. However, based on mtDNA data from 17 sites, a significant correlation (Mantel analysis, p = 0.035) was noted between genetic distance (FST) and PAH concentration but not between genetic distance and geographic distance. Mummichog from the most heavily PAH-contaminated site, Atlantic Wood (AW), were genetically distinct from those of other Elizabeth River sites. At AW, high frequencies of several divergent haplotypes were observed that were more closely allied to the northern mummichog than to the more abundant southern form in the Chesapeake Bay. These data suggested that a locally stable population existed at the AW site. This conclusion is consistent with the observation that mummichog from the AW site display enhanced tolerance to PAH contamination relative to mummichog from noncontaminated sites. Conclusions about gene diversity and the correlation between genetic distance with site differences in PAH concentrations were also consistent with those from tandem genetic analyses based on allozymes.
Population-level responses to long-term cadmium exposure in two strains of the freshwater gastropod Biomphalaria glabrata: Results from a life-table response experiment
Authors: Salice Christopher J. , Miller Thomas J. 
Published: March 2010

Abstract
A life-table response experiment was conducted to ascertain the demographic effects of low-level cadmium exposure on two strains, BS90 and NMRI, of the freshwater gastropod Biomphalaria glabrata. Snails were exposed to cadmium continuously from the embryonic stage through adulthood. Results indicated that cadmium significantly affected a number of individual-based parameters, including %hatch, juvenile survival, and adult survival in both strains. Also, fecundity and time to maturity were significantly affected in the NMRI strain. A stage-based, deterministic, population model indicated that population growth rate (Λ) was significantly affected by cadmium. Elasticity analysis indicated that juvenile survival, in general, had the greatest contribution to Λ. Decomposition analysis indicated that the effects of cadmium on the juvenile stage in BS90 and the embryonic stage in NMRI contributed most to cadmium-induced changes in Λ. The BS90 strain was more sensitive to cadmium toxicity than NMRI. Moreover, the two strains differed in pattern of response with different aspects of their respective life histories contributing to cadmiuminduced changes in Λ. Comparisons were also made between the main model, based on a Z transformation of the life-cycle graph, and more commonly used matrix models.
Enhancement of aerobic microbial degradation of polychlorinated biphenyl in soil microcosms
Authors: Manzano Manuel A. , Perales José A. , Sales Diego , Quiroga José M. 
Published: March 2010

Abstract
This article reports the results of various biodegradation experiments on polychlorinated biphenyl (PCB)-contaminated sandy soil employing a mixed culture of acclimatized bacteria. Following the optimization of different variables without chemical pretreatment, the elimination rate achieved of Aroclor® 1242 in slurry-phase reactors was 61% after four months of treatment, with the presence of biphenyl as cosubstrate being the most important factor affecting PCB biodegradation. The biodegradation occurred as a first-order process, and it proved most effective in respect to dichlorinated biphenyls (100% removal), followed by trichlorinated (92%) and tetrachlorinated biphenyls (24%). The results also showed that the degradability of PCBs in soil may be enhanced by an advanced oxidation pretreatment (Fenton reaction), producing almost 100% elimination of PCBs at the end of the integrated chemical-biological process and 72% mineralization of the intermediates generated during the chemical pretreatment.
Mineralization of aged atrazine, terbuthylazine, 2,4-D, and mecoprop in soil and aquifer sediment
Authors: Johannesen Helle , Aamand Jens 
Published: March 2010

Abstract
The effect of aging of the herbicides atrazine, terbuthylazine, 2,4-D, and mecoprop on their bioavailability to degrading microorganisms was studied in soil and aquifer sediment. 14C-ring-labeled herbicide (2.5 mg/kg) was added to sterilized soil or aquifer sediment and stored at 10°C for up to 103 d before inoculation with either the atrazine and terbuthylazine-degrading Pseudomonas sp. strain ADP (atrazine-degrading Pseudomonas) or an enriched culture able to mineralize 2,4-D and mecoprop. The initial mineralization rate and recovery of 14CO2 after 62 to 113 d of incubation were used as measures of the availability of the compounds to the microorganisms. Aging in soil reduced the initial mineralization of atrazine. Thus, only 17% of the added 14C-atrazine had been mineralized after 21 h of incubation when aged for 88 d as compared with 33% when the atrazine had been aged for 1 d. 14CO2 recovery was only 58% after 88 d of aging as compared with 81% when aged for 1 d. A similar effect of aging was seen with terbuthylazine. With 2,4-D, the effect of aging in soil on mineralization by the enriched culture was much smaller. Aging had no effect on mineralization of mecoprop in soil or on mineralization of any of the herbicides in aquifer sediment.
Degradation of carbazole, dibenzothiophene, and dibenzofuran at low temperature byPseudomonassp. strain C3211
Authors: Jensen Anne-Mette , Finster Kai Waldemar , Karlson Ulrich 
Published: March 2010

AbstractPseudomonas sp. strain C3211 was isolated from a temperate climate soil contaminated with creosote. This strain was able to degrade carbazole, dibenzothiophene and dibenzofuran at 10°C with acetone as a co-substrate. When dibenzothiophene was degraded by strain C3211, an orange compound, which absorbed at 472 nm, accumulated in the medium. Degradation of dibenzofuran was followed by accumulation of a yellowish compound, absorbing at 462 nm. The temperature optimum of strain C3211 for degradation of dibenzothiophene and dibenzofuran was at 20 to 21°C, while the maximum temperature for degradation was at 27°C. Both compounds were degraded at 4°C. Degradation at 10°C was faster than degradation at 25°C. This indicates that strain C3211 is adapted to life at low temperatures.
The application of high-performance liquid chromatography humic acid columns in determination of Koc of polycyclic aromatic compounds
Authors: Jonassen Kristoffer E. N. , Nielsen Torben , Hansen Poul Erik 
Published: March 2010

Abstract
An improvement of a method for determination of the distribution coefficient for polycyclic aromatic compounds (PAC) between organic carbon and water (Koc) by high-performance liquid chromatography (HPLC) is presented in this paper. By use of silica-based HPLC columns with chemically immobilized humic acid (Aldrich, Zigma-Aldrich, Taufkirchen, Germany), the retention of PAC to humic acid can be measured, and the results can, when they are compared to those from a blank column, be used to a direct determination of Koc. These values agree quite well with literature Koc values for two- to four-ringed PAC. Our work has shown that it is possible to use this method to investigate how environmental parameters like electrolyte concentration, pH, and temperature affect the sorption of PAC to humic acid. Thermodynamic parameters can be estimated from variable temperature experiments. The advantage of the method is its cost and manpower effectiveness.
Calculation of the interaction between dissolved organic carbon and organic micropollutants by three dimensional force field methods
Authors: Govers Harrie A. J. , van Roon André , Parsons John R. 
Published: March 2010

Abstract
A 3D optimized potential for liquid simulation (OPLS) force field method with 6–31 G* atomic charges and a geometrical optimization approach was studied for the calculation of enthalpies of transfer at 300 K of partitioning processes. A 3D fulvic acid model of dissolved organic carbon was built. Limonene, α-pinene, fluoranthene, p,p′-DDT, and 2,4-D were inserted into a general site of preference, and interaction energies were calculated. Energies of hydration were calculated and subtracted from fulvic acid-contaminant interactions. The resulting values for the enthalpies of transfer from water to dissolved organic carbon were -2.2, +0.9, -6.4, -4.0, and -4.3 kcal/mol for limonene, α-pinene, fluoranthene, p,p′-DDT, and 2,4-D, respectively. This led to a change of the partition constant by a factor of 0.17 to 1.27 at a temperature increase from 5 to 55°C. The values of fluoranthene and p,p′-DDT compared favorably with their experimental values of -4.4 and -5.0 kcal/mol. Prior to this, a general scaling factor for electrostatic interactions in both the pure liquid (sliq = 2.89) and the hydrated solute (shyd = 3.70) was derived from the experimental values of enthalpies of vaporization and aqueous solution. Resulting predicted enthalpies of vaporization deviated by -3.1 (water), 0.4 (limonene), 0.2 (α-pinene), 3.9 (fluoranthene), -3.0 (p,p′-DDT), and 0.9 (2,4-D) kcal/mol from experimental data, whereas enthalpies of aqueous solution deviated by -1.3 (limonene), -5.7 (α-pinene), 4.2 (fluoranthene), and 0.3 (p,p′-DDT) kcal/mol. Results are discussed in terms of molecular structures and their interactions.
A potential link between the turnover of soil organic matter and the release of aged organic contaminants
Authors: Reemtsma Thorsten , Savric Irena , Jekel Martin 
Published: March 2010

Abstract
Soil column experiments were conducted to investigate the release of aged organic contaminants (adsorbable organo-halogens, [AOX]) and the potential effects of microbial turnover of soil organic matter onto the contaminant release from two different soils of former wastewater infiltration sites. Under reference conditions, the total carbon flux ranged from 6 to 9 mg/kg/d from the two soils. More than 92% of it was due to mineralization (CO2) and below 8% to the dissolved organic carbon (DOC) in the column effluent. Despite very different organohalogen levels in the two soils, the fluxes of AOX were similar (1 μg/kg/d). Microbial activity was altered by changing temperature and the solution pH and by drying. In all experiments where increased microbial respiration (CO2 production) was observed, the release of organic contaminants in the column effluent also increased. Fluxes of nickel, zinc, and phosphate showed a completely different pattern, suggesting that their retention in soil is determined by chemical parameters. A linear correlation analysis provided clear evidence that AOX and DOC fluxes are closely linked to each other. However, the superimposition of abiotic and biotic processes in the soils did not allow a causal relation to be established between the mineralization of soil organic matter and the release of organic contaminants sequestered in the soil. Our findings suggest that microbial activity may have a significant impact on the extent to which contaminated soils may act as a source of persistent organic pollutants.
Availability of polycyclic aromatic hydrocarbons to earthworms (Eisenia andrei, Oligochaeta) in field-polluted soils and soil-sediment mixtures
Authors: Jager Tjalling , Baerselman Rob , Dijkman Ellen , de Groot Arthur C. , Hogendoorn Elbert A. , de Jong Ad , Kruitbosch Jantien A. W. , Peijnenburg Willie J. G. M. 
Published: March 2010

AbstractThe bioavailability of polycyclic aromatic hydrocarbons (PAHs) for earthworms (Eisenia andrei) was experimentally determined in seven field-polluted soils and 15 soil-sediment mixtures. The pore-water concentration of most PAHs was higher than predicted. However, most of the compound was associated with dissolved organic carbon (DOC) and not directly available for uptake by earthworms. The apparent sorption could be reasonably predicted on the basis of interactions with DOC; however, the biota-soil accumulation factors (BSAFs) for earthworms were up to two orders of magnitude lower than predicted by equilibrium partitioning. The large variability between sites was not fully explained by differences in sorption. Experimental results indicate that the pool of freely dissolved PAHs in the pore water became partially depleted because of uptake by the earthworms and that bioaccumulation is thus also influenced by the kinetics of PAH desorption and mass transport. A pilot study with Lumbricus rubellus showed that steady-state body residues were well correlated to E. andrei. Current results show that depositing dredge spoil on land may lead to increased bioavailability of the lower-molecular-weight PAHs. However, risk assessment can conservatively rely on equilibrium partitioning, but accurate prediction requires quantification of the kinetics of bioavailability.
Structural and functional approach to studying pesticide side-effects on specific soil functions
Authors: Liebich Jost , Schäffer Andreas , Burauel Peter 
Published: March 2010

Abstract
The microbial communities in the soil are responsible for material cycling and thus also for maintaining the fertilityof agricultural soils. In order to assess pesticide side effects on the soil processes, detailed knowledge is required about the structure and function of the soil microflora. Therefore, the degradation and humification of 14C-labeled maize straw was studied in processoriented microcosms. Apart from a native orthic luvisol, a heat-treated soil was used that has been freed from organic carbon by incineration at 600°C. Microbial communities involved in the turnover of the crop residues were investigated using denaturing gradient gel electrophoresis (DGGE) of 16S rDNA sequences. Both 13C-nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography were used to analyze humic acids produced in the microcosms. To evaluate the sensitivity of the microcosms, the influence of the fungicide dithianon was used in a case study at a concentration of 50 mg/kg. Microbial activity was reduced because of the application of the pesticide, especially in the native soils, while mineralization of 14C-labeled maize straw was only slightly affected. The buildup of fungal biomass was inhibited for at least three weeks. Despite these effects on the microbial communities, no significant differences in the humification products after 26 weeks of incubation were observed.
Effects of organic amendments on the toxicity and bioavailability of cadmium and copper in spiked formulated sediments
Authors: Besser John M. , Brumbaugh William G. , May Thomas W. , Ingersoll Christopher G. 
Published: March 2010

AbstractWe evaluated the partitioning and toxicity of cadmium (Cd) and copper (Cu) spiked into formulated sediments containing two types of organic matter (OM), i.e., cellulose and humus. Amendments of cellulose up to 12.5% total organic carbon (TOC) did not affect partitioning of Cd or Cu between sediment and pore water and did not significantly affect the toxicity of spiked sediments in acute toxicity tests with the amphipod Hyalella azteca. In contrast, amendments of natural humus shifted the partitioning of both Cd and Cu toward greater concentrations in sediment and lesser concentrations in pore water and significantly reduced toxic effects of both metals. Thresholds for toxicity, based on measured metal concentrations in whole sediment, were greater for both Cd and Cu in sediments amended with a low level of humus (2.9% TOC) than in sediments without added OM. Amendments with a high level of humus (8.9% TOC) eliminated toxicity at the highest spike concentrations of both metals (sediment concentrations of 12.4 μg Cd/g and 493 μg Cu/g). Concentrations of Cd in pore water associated with acute toxicity were similar between sediments with and without humus amendments, suggesting that toxicity of Cd was reduced primarily by sorption to sediment OM. However, toxic effects of Cu in humus treatments were associated with greater pore-water concentrations than in controls, suggesting that toxicity of Cu was reduced both by sorption and by complexation with soluble ligands. Both sorption and complexation by OM tend to make proposed sediment quality guidelines (SQGs) based on total metal concentrations more protective for high-OM sediments. Our results suggest that the predictive ability of SQGs could be improved by models of metal interactions with natural OM in sediment and pore water.