bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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 &lt; 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

Abstract
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

Abstract
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

Abstract
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.