bluuebunny/crossref_metadata_2025 huggingface dataset:
Deposition and dissipation of chlorpyrifos in surface water following vineyard applications in northern Italy
Authors: Capri Ettore , Balderacchi Matteo , Yon Denis , Reeves Graham
Published: March 2005

Chlorpyrifosi an insecticide approved globally for use on a wide range of crops. Laboratory sudies indicate that chlorpyrifos is toxic to fish and aquatic invertebrates, and so the adoption of practices that reduce aquatic exposure following use should be encouraged. This study assessed the exposure of surface water to the spray-drift of chlorpyrifos and the subsequent contamination of a realistic worst-case edge-of-field ditch in a vineyard in Northern Italy. Chlorpyrifos (DURSBAN 480 EC® [Dow Elanco, Indianapolis, IN, USA]) was applied according to local Good Agricultural Practice (GAP) on two vineyard plots using atomizer equipment. Drift deposition and subsequent dissipation of chlorpyrifos were then monitored in an adjacent, common ditch, with an inherent buffer zone of approximately 7 m between the treated area and the ditch. The results showed that the drift loadings under the study conditions could reach predicted levels from standard spray-drift tables. However, the measured drift was highly variable due to physical factors such as the crop canopy and the distribution of vines within the rows. The amount of chlorpyrifos deposited onto the surface of the ditch water and intercepted by paper strips was approximately 2% of the applied amount after the two applications, with a maximum concentration of approximately 0.3 μg L−1 immediately after the first application and 0.09 μg L−1 after the second, which then dissipated from the water column within 12 to 24 h. The results showed that drift deposition spatially was variable and that chlorpyrifos residues dissipated rapidly from this surface water body. Both aspects are considered important in order to refine the aquatic risk assessment at a higher tier for both registration and management purposes.
Prediction of large variation in biota to sediment accumulation factors due to concentration-dependent black carbon adsorption of planar hydrophobic organic compounds
Authors: Cornelissen Gerard , Gustafsson Örjan
Published: March 2005

Biota-to-sediment accumulation factors (BSAFs) sometimes show large variations between sites for a given planar hydrophobic organic compound (pHOC) in a given organism. We present a framework in which strong adsorption to soot/charcoal (black carbon [BC]) explains such BSAF variations. Recently constrained parameters on environmental BC sorption were used in a dual-mode sorption model of BSAF. Variations in sedimentary BC content are shown to explain variations in BSAF of one to two orders of magnitude. In addition, strong BC sorption can explain the often-observed difference in BSAF between polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The strong nonlinearity of BC sorption can render BSAF values strongly concentration-dependent for a given sediment/organism/compound combination, so it is of paramount importance to carry out uptake and toxicity tests at the relevant environmental concentrations.
Microbial inhibition by pharmaceutical antibiotics in different soils—dose-response relations determined with the iron(III) reduction test
Authors: Thiele-Bruhn Sören
Published: March 2005

Soil contamination from pharmaceuticals is an emerging problem, though quantitative data on their microbial effects are lacking. Thus, nine pharmaceutical antibiotics were tested for their effects on the microbial iron(III) reduction in six different topsoils. Complete dose-response curves were obtained and best-fit by sigmoidal Logit, Weibull, Box-Cox Logit, and Box-Cox Weibull equations (r2 0.73–1.00). The derived effective doses (ED [μmol/kg soil]) for the different antibiotics increased in the order (average ED50 in parentheses) chlortetracycline (53) < sulfadimethoxine (58) < oxytetracycline (170) < sulfadiazine (190) < sulfadimidine (270) = tetracycline (270) < sulfapyridine (430), though no effect was found for sulfanilamide and fenbendazole at doses up to 5,800 and 3,300 μmol/kg, respectively. Due to a strong soil adsorption, especially of the tetracyclines, the corresponding effective concentrations in the soil solution (EC50), derived from sorption experiments, were considerably smaller and ranged from 0.004 μmol/L (chlortetracycline) to 120 μmol/L (sulfapyridine). The effects of the antibiotics were governed by soil sorptive properties, especially the concentration of soil organic matter. The microbial inhibition was influenced indirectly by the soil pH, which affects the ionization status of the amphoteric antibiotics.
The contrasting roles of sedimentary plant-derived carbon and black carbon on sediment-spiked hydrophobic organic contaminant bioavailability to Diporeia species and Lumbriculus variegatus
Authors: Kukkonen Jussi V. K. , Mitra Siddhartha , Landrum Peter F. , Gossiaux Duane C. , Gunnarsson Jonas , Weston Donald
Published: March 2005

In bioavailability sudies, the biota sediment accumulation factor (BSAF) is invoked to describethe thermodynamic partitioning of a hydrophobic organic contaminant (HOC) between the organism lipid and the organic carbon fraction of the sedimentary matrix and accounts for differences in bioavailability among sediments. Bioaccumulation experiments were performed with Lumbriculus variegatus and Diporeia species exposed in seven sediments dosed with2,4,5,2′,4′,5′-hexachlorobiphenyl (HCBP) and benzo[a]pyrene (BaP) or pyrene (PY) and 3,4,3′,4′-tetrachlorobiphenyl (TCBP). The BSAF values for the nonplanar HCBP were consistent with equilibrium partitioning theory (EQP) and averaged 2.87 for L. variegatus and 1.45 for Diporeia, while the BSAF values for the planar compounds (BaP, PY, TCBP) were generally lower than estimated from EQP (<1). Correcting the BSAF values of the planar compounds for enhanced sorption due to black carbon improved the BSAF values for L. variegatus, generally resulting in values consistent with EQP, but substantial variation remained for Diporeia. The BSAF values for the planar compounds showed significant positive correlations with plant-derived carbon in sediments (lignin and pigments) but were more consistent for L. variegatus than for Diporeia. These correlations imply that compounds sorbed to plant-derived carbon are more bioavailable since this material is more likely ingested providing a second exposure route.
Toxicity of sixty-three metals and metalloids to Hyalella azteca at two levels of water hardness
Authors: Borgmann Uwe , Couillard Yves , Doyle Patrick , Dixon D. George
Published: March 2005

he toxicityofall atomically s able metals in the periodic table, excluding Na, Mg, K, and Ca, was measured in one-week exposures using the freshwater amphipod Hyalella azteca in both Lake Ontario, Canada, and soft water (10% Lake Ontario). Metals were added as atomic absorption standards (63 metals), and also as anion salts for 10 metals. Lethal concentrations resulting in 50% mortality (LC50s) were obtained for 48 of the metals tested; the rest were not toxic at 1,000 μg/L. The most toxic metals on a molar basis were Cd, Ag, Pb, Hg, Cr (anion), and Tl, with nominal LC50s ranging from 5 to 58 nmol/L (1 to 58 nmol/L measured). These metals were followed by U, Co, Os, Se (anion), Pt, Lu, Cu, Ce, Zn, Pr, Ni, and Yb with nominal LC50s ranging from 225 to 1,500 nmol/L (88–1,300 nmol/L measured). Most metals were similarly or slightly more toxic in soft water, but Al, Cr, Ge, Pb, and U were > 17-fold more toxic in soft water; Pd was less toxic in soft water. Atomic absorption (AA) standards of As and Se in acid had similar toxicity as anions, Sb was more toxic as the AA standard, and Cr and Mn were more toxic as anions. One-week LC50s for H. azteca correlate strongly with three-week LC50s and three-week effect concentrations resulting in 50% reduction in reproduction (EC50s) in Daphnia magna.
The role of cannibalism and contaminant source on bioaccumulation in aquatic food webs
Authors: Fraser Alison J. , Cahill Thomas M. , Lasenby David C. , Mackay Donald , Milford Lynne
Published: March 2005

Two aspects of bioaccumulation in an aquatic food web are explored. First, the possible implications of cannibalism, including the scavenging of conspecifics, as a factor influencing food web bioaccumulation and biomagnification are explored by examining the behavior of total polychlorinated biphenyls (PCBs) in a simple aquatic food web consisting of plankton, juvenile and adult Mysis relicta, Diporeia, and alewife. From an analysis of trophic transfer efficiencies and food consumption rates, it is concluded that, for M. relicta, a maximum extent of cannibalism in a population is about 10%, although certain individuals may be more cannibalistic. The model suggests that cannibalism and scavenging of dead conspecifics generally result in an increase in concentration by self-biomagnification, but the effect is small and unlikely to exceed 5% on the average. Concentration differences also are likely to result from changes in the relative amounts of the dietary components. Highly cannibalistic individuals may achieve higher levels of bioaccumulation. In extreme cases, the food web model becomes mathematically unstable because of excessive feedback of high concentrations. A major implication is that differences in extent of cannibalism and scavenging probably contribute significantly to natural concentration variation in a population. Second, and more important, is the effect of benthic versus pelagic sources, especially when significant fugacity differences exist between these zones. A simple method is described by which the separate contributions from these sources can be estimated for organisms at higher trophic levels.
Application of the ricewq—vadoft model for simulating the environmental fate of pretilachlor in rice paddies
Authors: Karpouzas Dimitrios Georgios , Ferrero Aldo , Vidotto Francesco , Capri Ettore
Published: March 2005

No validated models in Europe are capable of simulating the environmental fate of pesticides under the specific conditions of rice fields. Rice water quality—vadose zone flow and transport (RICEWQ-VADOFT) is a model developed from the coupling of a surface runoff model (RICEWQ) and a vadose zone flow and transport model (VADOFT) for determining predicted environmental concentrations in paddy water and sediment, runoff, and groundwater. This study is intended to evaluate the capability of this model to simulate effectively the environmental fate of the herbicide pretilachlor in the paddy environment. A two-year field study conducted in a representative rice-cultivated area of northern Italy provided measured concentrations of pretilachlor in paddy water and sediment and also a limited number of observations on runoff losses. The model successfully predicted the water balance in the paddy field in both years. After limited calibration, the model predicted the fate of pretilachlor in paddy water and sediment with high accuracy. Agreement between predicted and measured concentrations of pretilachlor in both years was assessed statistically using several statistical indicators. For example, modeling efficiency (EF) values of 0.867 to 0.935 and 0.702 to 0.718 in paddy water and sediment, respectively, document the strong agreement between predicted and measured pesticide concentrations. The model predictions showed high agreement with the limited amount of measured runoff data in 2002. The model predicted that no significant amounts of pretilachlor would leach below the top 25 cm of the soil, although no measured data were available to evaluate the predicted results. A sensitivity analysis of the model to variables controlling pesticide partitioning to paddy sediment (VBIND, depth for direct partitioning of pesticide to bed sediment; VMIX, mixing velocity by molecular diffusion) revealed that the predictions of pesticide leaching were influenced strongly by those variables. Generally the RICEWQ-VADOFT model is a useful modeling tool for pesticide risk assessment in rice paddies.
Different behavior of tetracyclines and sulfonamides in sandy soils after repeated fertilization with liquid manure
Authors: Hamscher Gerd , Pawelzick Heike Theresia , Höper Heinrich , Nau Heinz
Published: March 2005

Recently we showed that tetracyclines tend to persist and may accumulate in sandy soils after repeated fertilizations with liquid manure. We continued these field investigations from 2001 to 2003 and observed no further accumulation of tetracyclines in soil, but found that the average tetracycline concentration remained higher than 150 μg/kg soil. From 2000 to 2002, approximately 330 g tetracycline, 7 g chlortetracycline, 28 g sulfamethazine, and 57 g sulfadiazine per hectare were transferred via liquid manure to the topsoil (0–30 cm). Nevertheless, no leaching of tetracyclines into deeper soil segments or groundwater was observed. Furthermore, we developed new analytical methods for the detection of various sulfonamides in liquid manure, soil, and groundwater. Investigation of the same fields used in the tetracycline study showed that sulfamethazine occurred in concentrations approximately two orders of magnitude lower than that of tetracycline in the plow layer. Although there apparently were very low concentrations of sulfamethazine in soil, we detected it in groundwater sampled by suction probes at 1.4 m below soil surface in the spring of 2002. Further investigations confirmed these findings. To our knowledge, this is the first direct evidence of continuous leaching of a veterinary drug from soil into groundwater under field conditions. We conclude that tetracyclines and sulfonamides show distinctly different environmental behaviors. One explanation may be their different sorption coefficients in soil, indicating (in part) their different mobilities in this ecosystem.
Stage change in binding of pyrene to selected humic substances under different ionic strengths
Authors: Kuo Li-Jung , Lee Chon-Lin
Published: March 2005

Influence of ionic strength (I) on the pyrene binding constant (Koc) in six different humic substance (HS) solutions, three soil humic acids, one freshwater humic acid, one freshwater fulvic acid, and one freshwater natural organic matter was investigated by fluorescence quenching technique. Specific two-stage changes of Koc with increasing ionic strength were only observed in three soil humic acid solutions with varying to different extents. Two primary governing factors for the differences of these HS systems are binding potential and the abundance of acidic functional groups (carboxyl and phenolic) of HS. Experimental results demonstrated that within the ionic strength range studied in the present research, ionic strength had a major effect on molecular size of HS and brought about change of Koc. The salting-out effect did not. The change in molecular size was caused by the associations between cations and acidic groups of HS. Using pyrene as a probe, we also investigated the interaction of cation and dissolved HS and found relatively slow kinetics (at least 5 d), leading us to believe that the special cation-HS kinetics may influence the results of geochemical studies involving the measurement of ionic strength effect.
Copper uptake by Mytilus edulis in the presence of humic acids
Authors: Lorenzo J. Ignacio , Beiras Ricardo , Mubiana Valentine K. , Blust Ronny
Published: March 2005

The effects of humic acids (HA) on Cu up take by the blue mussel (Mytilus edulis) were studied in chemically defined seawater. Short-term uptake by excised gills was studied and compared with whole-mussel Cu accumulation. Copper uptake in gills is not a saturable process within the time frame and concentration range tested, being a linear function of time (0–120 min) and Cu concentration (0–150 μg/L). For the whole mussel, Cu uptake is not linear with time (0–72 h) and Cu concentration (0–130 μg/L). The presence of HA (0–10 mg/L) clearly reduced Cu uptake by gills, but it did not have such an effect on whole-animal uptake. A simple complexation model obtained from voltammetric measurements was used to determine the noncomplexed (labile) fraction of Cu in the presence of HA to test the effect of speciation on Cu uptake. In most cases, Cu uptake by gills was better explained by labile Cu concentrations than by total Cu exposure concentrations, which is in agreement with the free-ion activity model. In whole-animal experiments, Cu uptake was not related to labile Cu concentrations in the presence of HA, indicating that Cu-HA complexes are at least partially available for uptake by the mussels.
Soil-solution speciation of CD as affected by soil characteristics in unpolluted and polluted soils
Authors: Meers Erik , Unamuno Virginia , Vandegehuchte Michiel , Vanbroekhoven Karolien , Geebelen Wouter , Samson Roeland , Vangronsveld Jaco , Diels Ludo , Ruttens Ann , Laing Gijs Du , Tack Filip
Published: March 2005

Total metal content by itself is insufficient as a measure to indicate actual environmental risk. Understanding the mobility of heavy metals in the soil and their speciation in the soil solution is of great importance for accurately assessing environmental risks posed by these metals. In a first explorative study, the effects of general soil characteristics on Cd mobility were evaluated and expressed in the form of empirical formulations. The most important factors influencing mobility of Cd proved to be pH and total soil content. This may indicate that current legislation expressing the requirement for soil sanitation in Flanders (Belgium) as a function of total soil content, organic matter, and clay does not successfully reflect actual risks. Current legal frameworks focusing on total content, therefore, should be amended with criteria that are indicative of metal mobility and availability and are based on physicochemical soil properties. In addition, soil-solution speciation was performed using two independent software packages (Visual Minteq 2.23 and Windermere Humic Aqueous model VI [WHAM VI]). Both programs largely were in agreement in concern to Cd speciation in all 29 soils under study. Depending on soil type, free ion and the organically complexed forms were the most abundant species. Additional inorganic soluble species were sulfates and chlorides. Minor species in solution were in the form of nitrates, hydroxides, and carbonates, the relative importance of which was deemed insignificant in comparison to the four major species.
Influence of nutrient amendments on the phytoextraction of weathered 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene by cucurbits
Authors: White Jason C. , Parrish Zakia D. , Isleyen Mehmet , Gent Martin P. N. , Iannucci-Berger William , Eitzer Brian D. , Mattina Maryjane Incorvia
Published: March 2005

Field experiments were conducted to determine the impact of nutrient amendments on the phytoextraction of weathered 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (p,p′-DDE) by eight cultivars of cucurbits over a single growing season. Four cultivars of Cucurbita pepo ssp pepo are accumulators and extract percent level quantities of persistent organic pollutants (POPs), whereas C. pepo ssp ovifera and Cucumis sativus are nonaccumulators. The nonamended accumulators phytoextracted 1.0% of the p,p'-DDE and had a translocation factor of 0.44; however, the nonaccumulators removed 0.16% of the contaminant and had a translocation factor value of 0.09. The accumulators also had 3.8 times greater inorganic element content than the nonaccumulators. Duplicate mounds of each cultivar also received weekly nutrient amendments of phosphorus (400 mg/L K2HPO4), nitrogen (200 mg/L KNO3), or nitrogen/phosphorus (400 mg/L K2HPO4, 200 mg/L KNO3); a minus phosphorus treatment involved a 1-L addition of 1 g/L AlSO4 to the soil before planting. When normalized to respective control values (unamended vegetation), the root and stem p,p′-DDE bioconcentration factors (BCF) of the accumulator cultivars were significantly greater than those of the nonaccumulator cultivars under most nutrient regimes. The biomass of accumulator cultivars decreased by up to 61% under certain nutrient regimes, resulting in mixed effects on the amount of p,p′-DDE extracted. Treatment with N and P increased nonaccumulator biomass by 40 to 100%, and increased p,p′-DDE extraction from soil by 75%. Although generally assumed that fertilizer amendments will enhance phytoremediation, as evidenced here by the nonaccumulators, additions of macronutrients may reduce the phytoextraction of weathered POPs by C. pepo ssp pepo. These findings support our hypothesis that the ability of C. pepo ssp pepo to remove sequestered organic contaminants is governed by unique nutrient-acquisition mechanisms.
Is oxidative stress the mechanism of blue sac disease in retene-exposed trout larvae?
Authors: Bauder Matthew B. , Palace Vincent P. , Hodson Peter V.
Published: March 2005

Retene (7-isopropyl-1-methylphenanthrene) causes blue sac disease (BSD) in early life stages of fish, an effect similar to that of 2,3,7,8-tetrachlorodibenzo(p)dioxin. The signs of BSD include cytochrome P450 (CYP1A) induction, edema, hemor-rhaging, and craniofacial deformities, indicating membrane damage, circulatory failure, and impaired development. To test if the underlying cause was oxidative stress, rainbow trout (Oncorhynchus mykiss) larvae were exposed to waterborne retene or to known prooxidants (paraquat, t-butyl hydroperoxide, and carbon tetrachloride) in the presence or absence of vitamin E, an antioxidant. Fish exposed to retene showed an increased prevalence of BSD, reduced tissue concentrations of vitamin E and total glutathione, and a lower percentage of glutathione in a reduced form. Coexposure to vitamin E reduced the prevalence of BSD and restored tissue concentrations of vitamin E, but it did not affect retene uptake or tissue concentrations of glutathione. These responses are consistent with oxidative stress as a mode of action of retene. However, retene did not affect whole-body lipid peroxide concentrations, and prooxidants did not affect the prevalence of BSD and had only minimal effects on tissue glutathione and vitamin E. Possible explanations for these conflicting results include prooxidant exposures were insufficient to generate oxidative stress; lipid peroxidation may not be measurable in whole-body homogenates of retene-exposed fish if effects are localized to endothelial cells, where CYP1A enzymes are most induced; or retene may have an alternate mode of action (e.g., adduction of retene metabolites to lipids, protein, or DNA).
Squamous epithelial lesion of the mandibles and maxillae of wild mink (Mustela vison) naturally exposed to polychlorinated biphenyls
Authors: Beckett Kerrie J. , Millsap Stephanie D. , Blankenship Alan L. , Zwiernik Matthew J. , Giesy John P. , Bursian Steven J.
Published: March 2005

Aproximately125km of the KalamazooRiver, located in southwestern Michigan (USA), are designated as a Superfund site, with polychlorinated biphenyls (PCBs) as the contaminant of concern. Mink (Mustela vison) are a naturally occurring predator in this area and also a species of concern because of their known sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and structurally similar compounds, such as PCBs. Four of nine mink trapped from the Kalamazoo River area of concern (KRAOC) exhibited histological evidence of a jaw lesion previously identified in ranch mink. The jaw lesion, hyperplasia of squamous epithelium in the mandible and maxilla, is known to be caused by 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126) and TCDD. Mink trapped from an upstream reference area (Fort Custer Recreation Area [FCRA]) did not exhibit the lesion. Mean concentrations of total PCBs were 2.8 and 2.3 mg/kg wet weight in the livers of mink from the KRAOC and FCRA, respectively, and TCDD toxic equivalent (TEQ) concentrations were 0.30 and 0.11 μg/kg wet weight, respectively. Significant correlations were found between the severity of the lesion and the hepatic concentrations of total PCBs and TEQs. To our knowledge, this is the first published report of the lesion occurring in wild mink.
Aqueous photochemistry of triclosan: Formation of 2,4-dichlorophenol, 2,8-dichlorodibenzo-p-dioxin, and oligomerization products
Authors: Latch Douglas E. , Packer Jennifer L. , Stender Brian L. , VanOverbeke Jennifer , Arnold William A. , McNeill Kristopher
Published: March 2005

The photochemical fate of the antimicrobial agent triclosan is presented. Experiments performed in both natural and buffered deionized water show that triclosan rapidly photodegrades by direct photolysis (t½ = 5 h, pH 8, noon summer sunlight, 45°N latitude). Both 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) and 2,4-dichlorophenol (2,4-DCP) are produced. The 2,8-DCDD and 2,4-DCP also are photolabile and, thus, are intermediates. The yields for 2,8-DCDD and 2,4-DCP ranged from 3 to 12% depending on the conditions employed. When triclosan is photolyzed in the presence of Suwannee River (GA, USA) fulvic acid, a portion of the initial mass is recovered as insoluble material. Based on experiments in which the formation of insoluble material was monitored with photolysis time, it is postulated that photolysis in natural waters leads to some of the triclosan being coupled to humic matter. Triclosan also reacts rapidly with both singlet oxygen (krxn = 1.07 ± 0.03 × 108 M−1 s−1 in water of pH 10) and hydroxyl radical (k·OH = 5.4 ± 0.3 × 109 M−1 s−1). Indirect photolysis pathways, however, are not expected to be important because of low steady-state concentrations of reactive oxygen species in natural waters and the efficiency of the direct photolysis of triclosan.
Bench-scale evaluation of in situ bioremediation strategies for soil at a former manufactured gas plant site
Authors: Li Jun , Pignatello Joseph J. , Smets Barth F. , Grasso Domenico , Monserrate Esteban
Published: March 2005

We examined the biodegradation and desorption of a set of 15 polycyclic aromatic hydrocarbon (PAH) compounds in coal tar–contaminated soil at a former manufactured gas plant site to evaluate the feasibility of in situ bioremediation. Experiments were conducted in well-mixed aerobic soil suspensions containing various additives over a 93- to 106-d period. In general, both biotransformation and desorption decreased with PAH ring size, becoming negligible for the six-ring PAH compounds. Biodegradation by indigenous microorganisms was strongly accelerated by addition of inorganic nutrients (N, P, K, and trace metals). The rates of biotransformation of PAH compounds by indigenous microorganisms in nutrient-amended flasks outpaced their maximum (i.e., chelate-enhanced) rates of desorption to an infinite sink (Tenax®) in sterilized systems run in parallel, suggesting that indigenous organisms facilitated desorption. Biodegradation by indigenous organisms in nutrient-amended flasks appeared to be unaffected by the addition of a site-derived bacterial enrichment culture, resulting in approximately 100-fold higher aromatic dioxygenase levels, and by the addition of 0.01 M chelating agent (citrate or pyrophosphate), although such chelating agents greatly enhanced desorption in microbially inactivated flasks. The strong ability of nutrients to enhance degradation of the bioavailable PAHs indicates that their persistence for many decades at this site likely results from nutrient-limited natural biodegradation, and it also suggests that an effective strategy for their bioremediation could consist simply of adding inorganic nutrients.
Perfluoroalkyl contaminants in liver tissue from East Greenland polar bears (Ursus maritimus)
Authors: Smithwick Marla , Muir Derek C. G. , Mabury Scott A. , Solomon Keith R. , Martin Jonathan W. , Sonne Christian , Born Erik W. , Letcher Robert J. , Dietz Rune
Published: March 2005

Perfluoroalkyl substances were determined in polar bears (Ursus maritimus) collected in East Greenland (69°00′N to 74°00′'N) to compare with other populations and to examine effects of age and gender on concentrations of these contaminants. Hepatic tissue (n = 29) was analyzed for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate, heptadecafluorooctane sulfonamide (PFOSA), and perfluoroalkyl carboxylates (PFCAs) with C9–C15 perfluorinated carbon chains by liquid chromatography tandem mass spectrometry. Concentrations of PFOS found in samples from East Greenland (mean = 2,470 ± 1,320 ng/g wet weight) were similar to Hudson Bay, Canada, and both populations had significantly greater concentrations than those reported for Alaska, suggesting a spatial trend. Male bears showed a significant increase in concentration up to age six for PFCAs with C10–C14 carbon chains (r2 ≥ 0.50, p ≤ 0.05). Significant correlations were found between adjacent chain length PFCAs, (e.g., PFNA to PFDA: p < 0.05; r2 = 0.90). This may indicate a common source for these chemicals, although the specifics of source and mode of transport are unknown. No significant correlations were found between concentrations of PFCAs in liver tissue and previously reported polychlorinated biphenyl (PCB) congeners analyzed in fat samples from the same bears.
Uptake and tissue-specific distribution of selected polychlorinated biphenyls in developing chicken embryos
Authors: Maervoet Johan , Beck Veerle , Roelens Simon A. , Covaci Adrian , Voorspoels Stefan , Geuns Jan M. C. , Darras Veerle M. , Schepens Paul
Published: March 2005

Fertilized chicken eggs were injected with highdosesof individual polychlorinated biphenyl (PCB) congeners (0.5 μg of PCB 77, 9.8 μg of PCB 153, or 10.9 μg of PCB 180) before incubation to investigate the structure-specific uptake of these compounds by the embryo and their accumulation in brain and liver tissue. In accordance with earlier publications, a gradual uptake and accumulation of these compounds was observed during the last week of embryonic development. The PCB uptake and distribution to the specific tissues did not appear to be structure dependent. Wet-weight liver PCB concentrations (18, 266, and 278 ng/g at hatching for PCB 77, PCB 153, and PCB 180, respectively) were consistently two- to fourfold higher than carcass levels (7 ng/g of PCB 77, 117 ng/g of PCB 153, and 81 ng/g of PCB 180 at hatching). Whereas liver and carcass concentrations increased exponentially between day 13 of incubation and hatching, PCB levels in brain tissue remained unaltered (range, 0.6–1.0 ng/g of PCB 77 and 8–12 ng/g of PCB 153 and PCB 180 throughout the last week of incubation). Lipid analysis of the organs suggested that the lipid composition of brain may be an important factor explaining the low PCB accumulation in this tissue.
The use of terrestrial and aquatic microcosms and mesocosms for the ecological risk assessment of veterinary medicinal products
Authors: Van den Brink Paul J. , Tarazona José V. , Solomon Keith R. , Knacker Thomas , Van den Brink Nico W. , Brock Theo C. M. , Hoogland J. P. (Hans)
Published: March 2005

In this paper, we investigate the applicability of experimental model ecosystems (microcosms and mesocosms) for the ecological risk assessment of veterinary medicinal products (VMPs). VMPs are used in large quantities, but the assessment of associated risks to the environment is limited, although they are continually infused into the environment via a number of routes. It is argued that the experience obtained by pesticide research largely can be used when evaluating VMPs, although there are several major differences between pesticides and pharmaceuticals (e.g., knowledge of their mechanisms of action on nontarget organisms). Also, because microorganisms are often the target organisms of VMPs, risk assessment should focus more on endpoints describing functional processes. This paper provides a review of the current risk assessment schemes of Europe and North America along with examples of experiments already performed with veterinary medicinal products in aquatic and terrestrial ecosystem models. We suggest that some of the approaches developed for pesticide risk assessment can be used for VMPs and offer suggestions for the development of a framework for ecological risk assessment of VMPs.
Effect of species differences, pollutant concentration, and residence time in soil on the bioaccumulation of 2,2-BIS (p-chlorophenyl)-1,1-dichloroethylene by three earthworm species
Authors: Kelsey Jason W. , Colino Allison , White Jason C.
Published: March 2005

Laboratory experiments were conducted to study the effects of species differences, soil concentration, and contaminant-residence time in soil on the bioaccumulation factor (BAF; dry-weight ratio of contaminant concentration in the tissue to that in the soil) of 2,2-bis (p-chlorophenyl)-1,1-dichloroethylene (p,p‘-DDE’) for three species of earthworms. In four field-weathered soils, the BAF for Eisenia foetida, an epigeic species (surface habitat), was approximately 10-fold higher than those for Lumbricus terrestris, an anecic species (deep habitat) and Aporrectodea caliginosa, an endogeic species (habitat within the soil profile). Preliminary analysis indicates that BAF may decline with increasing pollutant concentration in soil. With regard to contaminant-residence time, the BAF for E. foetida was lower in weathered soils relative to that in freshly amended soils, but age of p,p‘-DDE’ did not significantly alter the BAF for A caliginosa. These data suggest total chemical concentration alone is not a reliable indicator of the toxicological significance of a contaminated soil and that species-specific differences and environmental factors significantly impact overall exposure and risk.
Maximum capacities for adsorption of phenanthrene in the slowly and very slowly desorbing domains in nineteen soils and sediments
Authors: van den Heuvel Henny , Couriaut Thomas Le , McMullen Brian M. , Lozac'h Frédéric , van Noort Paul
Published: March 2005

The maximum amounts of phenanthrene that can be taken up in both the slowly desorbing domain and the very slowly desorbing domain of 19 soils and sediments were determined by measuring the desorption of phenanthrene added at high loadings associated with equilibrium concentrations in water close to the aqueous solubility of phenanthrene. For two soils and one sediment, literature values for Langmuir phenanthrene adsorption capacities were available. These values were almost equal to the sum of the maximum amounts taken up in the slowly and in the very slowly desorbing domain. For the other soils, the range of the sum of the maximum amounts in the slowly and very slowly desorbing domains was comparable to the range for literature values of Langmuir phenanthrene adsorption capacities for soils and sediments. Results suggested that the maximum amounts determined from the desorption studies were Langmuir adsorption capacities. The correlation of maximum capacities for adsorption in both the slow desorption domain as well as the very slow desorption domain with soot content was virtually absent. In contrast, the variation of maximum amounts of phenanthrene adsorbed in either the slowly or the very slowly desorbing domains was substantially reduced by normalization to the total organic carbon content of the soils and sediments. It is suggested that adsorption in the slowly and very slowly desorbing domain took place in organic matter derived material such as kerogen, charcoal, or char.
Salivary Actinomyces naeslundii Genospecies 2 and Lactobacillus casei Levels Predict Pregnancy Outcomes
Authors: Dasanayake Ananda P. , Li Yihong , Wiener Howard , Ruby John D. , Lee Men‐Jean
Published: March 2005

Background: Gravida's poor periodontal health is emerging as a modifiable independent risk factor for preterm delivery and low birth weight.

Methods: To test the hypothesis that oral bacteria other than periodontal pathogens are also associated with pregnancy outcomes, specific oral bacterial levels measured during pregnancy were evaluated in relation to gestational age and birth weight while controlling for demographic, medical, and dental variables. The study population consisted of 297 predominantly African‐ American women who were pregnant for the first time. The salivary bacterial levels evaluated were Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinus, Lactobacillus acidophilus, Lactobacillus casei, Actinomyces naeslundii genospecies (gsp) 1 and 2, total streptococci, and total cultivable organisms.

Results: For 1 unit increase in log10A. naeslundii gsp 2 levels, there was a 60 gm decrease in birth weight (β = −59.7 g; SE = 29.1; P = 0.04), and a 0.17 week decrease in gestational age (β = −0.17 wk; SE = 0.09; P = 0.05). In contrast, per 1 unit increase in log10L. casei levels, there was a 42 gm increase in birth weight (β = 42.2 g; SE = 19.3; P = 0.03), and a 0.13 week increase in gestational age (β = 0.13 week; SE = 0.06; P = 0.04).

Conclusions: We conclude that other oral bacterial species can also be related to pregnancy outcomes in addition to previously reported periodontal pathogens. These organism levels may not only predict poor pregnancy outcomes, but also be used as modifiable risk factors in reducing prematurity and low birth weight. J Periodontol 2005;76:171‐177.
Non‐Surgical Periodontal Therapy of Shallow Gingival Recession Defects: Evaluation of the Restorative Capacity of Marginal Gingiva After 12 Months
Authors: Aimetti Mario , Romano Federica , Peccolo Daniela C. , Debernardi Cesare
Published: March 2005

Background: There is a large amount of data on surgical root coverage procedures for the treatment of gingival recessions but no controlled clinical trials on the behavior of marginal gingiva following non‐surgical therapy. The aim of our study was to compare in terms of root coverage two different modalities of root surface treatment, root planing and polishing versus polishing alone, over a 12‐month period.

Methods: The study was conducted in a split‐mouth design. Twenty‐four non‐smoking patients (14 females and 10 males, mean age 25.17 ± 4.03 years) with high levels of oral hygiene (full‐mouth plaque score <20%) and with two bilateral Class I buccal recessions up to 2 mm deep were selected for the study. In each patient one recession was randomly assigned to the test group and the contra‐lateral one to the control group. In the test group the exposed root surface was gently debrided and polished with mini curets and mini rubber cups, while the control group was polished only. The root surface instrumentation was repeated twice a month during the first 2 months and at 2‐month intervals over the next 10 months. Clinical measurements were taken at baseline and 12 months post‐therapy.

Results: At baseline the mean recession depth in the test group was 1.64 ± 0.37 mm and in the control sites 1.43 ± 0.42 mm, which decreased at 12 months to 0.78 ± 0.60 mm and to 1.34 ± 0.45 mm, respectively. The difference between the two groups was significant (P <0.0001). No significant differences were observed in keratinized tissue width and probing depth improvements.

Conclusions: The removal of microbial toxins from the exposed root surfaces by polishing prevents further progression of gingival recession; the reduction of root convexity by scaling and root planing promotes the coronal shift of the gingival margin. J Periodontol 2005;76:256‐261.
Correlation for the partition behavior of proteins in aqueous two‐phase systems: Effect of surface hydrophobicity and charge
Authors: Andrews B.A. , Schmidt A.S. , Asenjo J.A.
Published: March 2005

Correlations to describe the effect of surface hydrophobicity and charge of proteins with their partition coefficient in aqueous two‐phase systems were investigated. Polyethylene glycol (PEG) 4000/phosphate, sulfate, citrate, and dextran systems in the presence of low (0.6% w/w) and high (8.8% w/w) levels of NaCl were selected for a systematic study of 12 proteins. The surface hydrophobicity of the proteins was measured by ammonium sulfate precipitation as the inverse of their solubility. The hydrophobicity values measured correlated well with the partition coefficients, K, obtained in the PEG/salt systems at high concentration of NaCl (r = 0.92–0.93). In PEG/citrate systems the partition coefficient correlated well with protein hydrophobicity at low and high concentrations of NaCl (r = 0.81 and 0.93, respectively). The PEG/citrate system also had a higher hydrophobic resolution than other systems to exploit differences in the protein's hydrophobicity. The surface charge and charge density of the proteins was determined over a range of pH (3–9) by electrophoretic titration curves; PEG/salt systems did not discriminate well between proteins of different charge or charge density. In the absence of NaCl, K decreased slightly with increased positive charge. At high NaCl concentration, K increased as a function of positive charge. This suggested that the PEG‐rich top phase became more negative as the concentration of NaCl in the systems increased and, therefore, attracted the positively charged proteins. The effect of charge was more important in PEG/dextran systems at low concentrations of NaCl. In the PEG/dextran systems at lower concentration of NaCl, molecular weight appeared to be the prime determinant of partition, whereas no clear effect of molecular weight could be found in PEG/salt systems. © 2005 Wiley Periodicals, Inc.
Studies on epidermal growth factor receptor signaling in vertebrate limb patterning
Authors: Omi Minoru , Fisher Melanie , Maihle Nita J. , Dealy Caroline N.
Published: March 2005

The epidermal growth factor receptor (EGFR) regulates multiple patterning events in Drosophila limb development, but its role in vertebrate limb morphogenesis has received little attention. The EGFR and several of its ligands are expressed in developing vertebrate limbs in manners consistent with potential patterning roles. To gain insight into functions of EGFR signaling in vertebrate limb development, we expressed a constitutively active EGFR in developing chick limbs in ovo. Expression of activated EGFR causes pre‐ and postaxial polydactyly, including mirror‐image–type digit duplication, likely due to induction of ectopic expression and/or modulation of genes involved in anterior–posterior (AP) patterning such as Sonic hedgehog (Shh), dHand, Patched (Ptc), Gli3, Hoxd13, Hoxd11, bone morphogenetic protein 2 (Bmp2), Gremlin, and FGF4. Activation of EGFR signaling dorsalizes the limb and alters expression of the dorsal–ventral (DV) patterning genes Wnt7a, Lmx, and En1. Ectopic and/or extended FGF8 expressing apical ectodermal ridges (AERs) are also seen. Interdigital regression is inhibited and the digits fail to separate, leading to syndactyly, likely due to antiapoptotic and pro‐proliferative effects of activated EGFR signaling on limb mesoderm, and/or attenuation of interdigital Bmp4 expression. These findings suggest potential roles for EGFR signaling in AP and DV patterning, AER formation, and cell survival during limb morphogenesis. Developmental Dynamics 233:288–300, 2005. © 2005 Wiley‐Liss, Inc.
Mechanical strain injury increases intracellular sodium and reverses Na+/Ca2+ exchange in cortical astrocytes
Authors: Floyd Candace L. , Gorin Fredric A. , Lyeth Bruce G.
Published: March 2005

Traditionally, astrocytes have been considered less susceptible to injury than neurons. Yet, we have recently shown that astrocyte death precedes neuronal death in a rat model of traumatic brain injury (TBI) (Zhao et al.: Glia 44:140–152, 2003). A main mechanism hypothesized to contribute to cellular injury and death after TBI is elevated intracellular calcium ([Ca2+]i). Since calcium regulation is also influenced by regulation of intracellular sodium ([Na+]i), we used an in vitro model of strain‐induced traumatic injury and live‐cell fluorescent digital imaging to investigate alterations in [Na+]i in cortical astrocytes after injury. Changes in [Na+]i, or [Ca2+]i were monitored after mechanical injury or L‐glutamate exposure by ratiometric imaging of sodium‐binding benzofuran isophthalate (SBFI‐AM), or Fura‐2‐AM, respectively. Mechanical strain injury or exogenous glutamate application produced increases in [Na+]i that were dependent on the severity of injury or concentration. Injury‐induced increases in [Na+]i were significantly reduced, but not completely eliminated, by inhibition of glutamate uptake by DL‐threo‐β‐benzyloxyaspartate (TBOA). Blockade of sodium‐dependent calcium influx through the sodium‐calcium exchanger with 2‐[2‐[4‐(4‐Nitrobenzyloxy)phenyl]ethyl]isothiourea mesylate (KB‐R7943) reduced [Ca2+]i after injury. KB‐R7943 also reduced astrocyte death after injury. These findings suggest that in astrocytes subjected to mechanical injury or glutamate excitotoxicity, increases in intracellular Na+ may be a critical component in the injury cascade and a therapeutic target for reduction of lasting deficits after traumatic brain injury. © 2005 Wiley‐Liss, Inc.
The relationship of maternal attributes, resources, and perceptions of postpartum experiences to depression
Authors: Horowitz June Andrews , Damato Elizabeth G. , Duffy Mary E. , Solon Lori
Published: March 2005

The relationships of maternal attributes, resources, and perceptions of the postpartum experience to postpartum depression (PPD) were examined. One hundred and forty‐three mothers completed measures of maternal attributes, resources, and perceptions of the postpartum experience, as well as depressed mood and clinical depression symptoms. Results from canonical correlation analysis revealed two patterns. Pattern 1: Women without history of depression, more emotional support from partners, higher parenting evaluation, lower centrality of the infant in the mother's thoughts and actions, and fewer life changes had lower depressed mood and fewer clinical depression symptoms than their counterparts. Pattern 2: Mothers without history of depression who were married, with higher financial stress, and lower parenting evaluation had higher depressed mood, but not more clinical depression symptoms. Maternal age, parity, time since delivery, income, and help from partner were unrelated to either depression indicator. These patterns suggest multiple paths to PPD, and the need for routine mental health assessment and exploration of women's perceptions of their postpartum experience. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28:159–171, 2005
Health care and social service use among Chinese Immigrant elders
Authors: Aroian Karen J. , Wu Bei , Tran Thanh V.
Published: March 2005

We explored patterns and reasons for health and social service use among Chinese immigrant elders. Interviews were conducted with 27 Chinese immigrant elders, 11 adult care giving children, and 12 health and social service providers. Content analysis of these data indicated that participants across groups agreed that Chinese elders underutilize services because of problems related to language, transportation, cost, long waits for appointments, and because of cultural norms/values related to need for care, preference for self‐over professional care, fear, and distrust of western biomedicine, and the obligation to refrain from using formal services. These problems are complicated by geographical dispersion and dialect differences in the local Chinese immigrant community. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28:95–105, 2005
Participation in clubs and groups from childhood to adolescence and its effects on attachment and self‐esteem
Authors: McGee Rob , Williams Sheila , Howden‐Chapman Philippa , Martin Jennifer , Kawachi Ichiro
Published: March 2005

We examined social participation in organized clubs and groups from childhood to adolescence in a sample of young people from Dunedin, New Zealand. Groups were broadly categorized as “sports” and “cultural/youth” groups. While the results indicated high levels of participation in childhood with a decline over the ensuing adolescent years, path analyses suggested strong continuities in participation over time. Both family “active‐recreational” orientation (ARO) and “intellectual‐cultural” orientation (ICO) predicted participation, and mediated the effects of disadvantage on participation. Participation was significantly related to adolescent attachment to parents, friends and school/workplace, as well as self‐perceived strengths, after controlling for early family disadvantage and social support, peer attachment and literacy. The effect of participation in adolescence is to widen the “social convoy” to which young people are exposed as well as strengthening relationships within that convoy.