bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined effects of humic acids and salinity on solid-phase microextraction of DDT and chlorpyrifos, an estimator of their bioavailability
Authors: Mézin Laurent C. , Hale Robert C. 
Published: March 2005

Abstract
The unbound portion of dissolved hydrophobic environmental contaminants generally is presumed to be the most bioavailable to aquatic organisms. The effects of differing concentrations of Aldrich humic acid (HA) and salinity on the freely dissolved fraction of chlorpyrifos (CPF) and 4,4′-dichlorodiphenyltrichloroethane (DDT) in water were assessed through their relative uptake by solid-phase microextraction (SPME). This extraction method has been recently suggested as a valuable biomimetic tool. Increasing salinity (0–20 parts per thousand [%]) alone had no effect on the uptake of DDT by the SPME fiber, but generally enhanced the SPME uptake of the more water soluble CPF. Solid-phase microextraction uptake of DDT was decreased at an HA concentration of 10 mg/L, but 100 mg/L was required to decrease CPF uptake. Binding of CPF and DDT by HA was greatly reduced by the presence of salt at 5 to 20%. The extent of the HA and salinity effects appeared to be pesticide-dependent. These factors may ultimately impact the contaminant's environmental fate, transport, and bioavailability, for example, in estuarine situations.
Toxicity of mono- and diesters of o-phthalic esters to a crustacean, a green alga, and a bacterium
Authors: Jonsson Susanne , Baun Anders 
Published: March 2005

Abstract
The degradation of phthalic acid diesters may lead to formation of o-phthalic acid and phthalic acid monoesters. The ecotoxic properties of the monoesters have never been systematically investigated, and concern has been raised that these degradation products may be more toxic than the diesters. Therefore, the aquatic toxicity of phthalic acid, six monoesters, and five diesters of o-phthalic acid was tested in three standardized toxicity tests using the bacteria Vibrio fischeri, the green algae Pseudokirchneriella subcapitata, and the crustacean Daphnia magna. The monoesters tested were monomethyl, monoethyl, monobutyl, monobenzyl, mono(2-ethylhexyl), and monodecyl phthalate, while the diesters tested were dimethyl, diethyl, dibutyl, butylbentyl, and di(2-ethylhexyl)phthalate, which were assumed to be below their water solubility. The median effective concentration (EC50) values for the three organisms ranged from 103 mg/L to &gt;4,710 mg/L for phthalic acid, and corresponding values for the monoesters ranged from 2.3 mg/L (monodecyl phthalate in bacteria test) to 4,130 mg/L (monomethyl phthalate in bacteria test). Dimethyl and diethyl phthalate were found to be the least toxic of the diesters (EC50 26.2–377 mg/L), and the toxicity of the other diesters (butylbenzyl and dibutyl phthalate) ranged from 0.96 to 7.74 mg/L. In general, the phthalate monoesters (degradation products) were less toxic than the corresponding diesters (mother compounds).
Influence of hydroxypropyl-β-cyclodextrin on the extraction and biodegradation of phenanthrene in soil
Authors: Reid Brian J. , Stokes Joanna D. , Jones Kevin C , Semple Kirk T. 
Published: March 2005

Abstract
A study was conducted to investigate the effect of hydroxypropyl-β-cyclodextrin (HPCD) on the aging and biodegradation of phenanthrene (PHE) in soil. Soil was spiked with PHE at 25 mgPHE/kgSOIL and HPCD at a range of concentrations from 0 to 3.5 gHPCD/kgSOIL and aged for 1, 84, and 322 d. At each time point, a variety of analyses were performed to assess the loss and aging of the PHE in the soil. Methods included determination of total PHE remaining, dichloromethane (DCM) and butan-1-ol (BuOH) extractions, and determination of PHE extractable by an aqueous HPCD shake extraction. Mineralization assays were also carried out to assess the availability of the PHE to a PHE-degrading bacterial inoculum. It was found that the presence of HPCD in the soils increased PHE loss from the aged soil systems, particularly at the higher application rates. Dichloromethane and BuOH extractabilities were reduced with aging and increasing HPCD concentration, as was the amount of PHE that was extractable using an aqueous HPCD shake extraction or that was available for mineralization. The DCM and BuOH extraction yielded similar results, and both greatly overestimated the availability of the PHE to the degraders, whereas the HPCD extraction results were very similar to that of PHE biodegradation. This study indicates that cyclodextrins have potential for use as alternatives to surfactants in enhancing the desorption/solubilization and degradation of recalcitrant organic contaminants in soil.
Trace metal availability and effects on benthic community structure in floodplain lakes
Authors: Van Griethuysen Corine , Van Baren Joyce , Peeters Edwin T. H. M. , Koelmans Albert A. 
Published: March 2005

Abstract
Effects of contaminants on communities are difficult to assess and poorly understood. We analyzed in situ effects of trace metals and common environmental variables on benthic macroinvertebrate communities in floodplain lakes. Alternative measures of trace metal availability were evaluated, including total metals, metals normalized on organic carbon (OC) or clay, simultaneously extracted metals (SEM), combinations of SEM and acid-volatile sulfide (AVS), and metals accumulated by detritivore invertebrates (Oligochaeta). Accumulated metal concentrations correlated positively with sediment trace metals and negatively with surface water dissolved OC. Sixty-eight percent of the variation in benthic community composition was explained by a combination of 11 environmental variables, including sediment, water, and morphological characteristics with trace metals. Metals explained 2 to 6% of the community composition when SEM — AVS or individual SEM concentrations were regarded. In contrast, total, normalized, and accumulated metals were not significantly linked to community composition. We conclude that examination of SEM or SEM — AVS concentrations is useful for risk assessment of trace metals on the community level.
Comparing behavioral and chronic endpoints to evaluate the response of Lumbriculus variegatus to 3,4,3′,4′-tetrachlorobiphenyl sediment exposures
Authors: Landrum Peter F. , Leppänen Matti , Robinson Sander D. , Gossiaux Duane C. , Burton G. Allen , Greenberg Marc , Kukkonen Jussi V. K. , Eadie Brian J. , Lansing Margaret B. 
Published: March 2005

Abstract
The response of Lumbriculus variegatus to 3,4,3′,4′-tetrachlorobiphenyl (TCBP) was examined with feeding behavior and changes in carbon assimilation by using stable carbon isotopes at 22 and 10°C. The classical measure of feeding behavior determined on a subset of sediment for which the biological burial rate was determined in a companion study allowed direct method comparison. This comparison helped address relationships between biological burial rate, feeding rate, and bioaccumulation. The change in stable isotope composition reflects the total metabolic activity by measuring carbon assimilation rate and was compared to feeding rate, biological burial rate (as determined in the companion study), and reproduction. Decreasing the temperature from 22 to 10°C resulted in a twofold reduction in feeding rate and carbon assimilation. The fractional decline in feeding rate relative to the control mimicked the decline in the biological burial rate with increasing TCBP concentration that was found in the companion study. The bioaccumulation factor declined with increasing TCBP sediment concentration, tracking the feeding rate decline. Stable isotope measures showed differences in metabolic rates between the exposure temperatures but did not distinguish a metabolic rate change at 22°C among TCBP treatments. Likewise, reproduction declined from 22 to 10°C, with no reproduction at 10°C. Like the stable isotope measure, no dose response was found among TCBP treatments at 22°C. The reduction in carbon assimilation rate tracked the reduction in reproduction with lower temperature.
Reproductive and developmental effects of atrazine on the estuarine meiobenthic copepod Amphiascus tenuiremis
Authors: Bejarano Adriana C. , Chandler G. Thomas 
Published: March 2005

Abstract
Atrazine is one of the most widely used herbicides in the United States. Atrazine concentrations in coastal environments chronically range from 90 ng/L to 46 μg/L, with rare but measured concentrations near 60 μg/L at edge-of-field conditions. Chronic atrazine effects on estuarine benthos exposed to environmentally relevant concentrations are unknown. The purpose of this research was to assess atrazine reproductive and developmental effects over multiple-generation exposures of the copepod Amphiascus tenuiremis. Copepods were chronically exposed to two environmentally relevant nominal atrazine concentrations (2.5 and 25 μg/L, and to an environmentally unrealistic concentration (250 μg/L). Chronic exposures were performed using a 96-well microplate life cycle bioassay. Individual stage I copepodites (C1, n = 60/treatment) were reared through two generations (F0 and F1) to sexual maturity and individually mated in microwells containing 200 μl of atrazine solution. Copepod survival across all treatments and generations was &gt;95%. Atrazine did not affect development to reproductive maturity, time to egg extrusion, or time to egg hatch (p &gt; 0.05). However, reproductive failures increased across generations with increasing atrazine concentrations. Reproductive failures in the 0-, 2.5-, 25-, and 250-μg/L atrazine treatments were 11, 11, 20, and 24% for the F0 and 4, 9, 26, and 38% for the F1, respectively. Compared to controls, total nauplii production per female was reduced by approximately 22% in F0 females exposed to 250 μg/L atrazine (p &lt; 0.05), and by approximately 23%, approximately 27%, and approximately 32% in F1 females exposed to 2.5-, 25-, and 250-μg/L atrazine treatments, respectively (p &lt; 0.05). The combined effect of reproductive failure and reduced offspring production significantly reduced total population growth in the F1 generation (p &lt; 0.05) even at atrazine concentrations lower than that considered safe for seawater chronic exposure (26 μg/L).
Reduction of halogenated ethanes by green rust
Authors: O'Loughlin Edward J. , Burris David R. 
Published: March 2005

Abstract
Green rusts, mixed FeII/FeIII hydroxide minerals present in many suboxic environments, have been shown to reduce a number of organic and inorganic contaminants. The reduction of halogenated ethanes was examined in aqueous suspensions of green rust, both alone and with the addition of AgI (AgGR) and CuII (CuGR). Hexachloroethane (HCA), pentachloroethane (PCA), 1,1,1,2-tetrachloroethane (1,1,1,2-TeCA), 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA), 1,1,1-trichloroethane (1,1,1-TCA), 1,1,2-trichloroethane (1,1,2-TCA), 1,1-dichloroethane (1,1-DCA), and 1,2-dibromoethane were reduced in the presence of green rust alone, AgGR, or CuGR; only 1,2-dichloroethane and chloroethane were nonreactive. The reduction was generally more rapid for more highly substituted ethanes than for ethanes having fewer halogen groups (HCA &gt; PCA &gt; 1,1,1,2-TeCA &gt; 1,1,1-TCA &gt; 1,1,2,2-TeCA &gt; 1,1,2-TCA &gt; 1,1-DCA), and isomers with the more asymmetric distributions of halogen groups were more rapidly reduced than the isomer with greater symmetry (e.g., 1,1,1-TCA &gt; 1,1,2-TCA). The addition of AgI or CuII to green rust suspensions resulted in a substantial increase in the rate of halogenated ethane reduction as well as significant differences in the product distributions with respect to green rust alone.
Assessing trace-metal exposure to American dippers in mountain streams of southwestern British Columbia, Canada
Authors: Morrissey Christy A. , Bscendell-Young Leah I. , Elliott John E. 
Published: March 2005

Abstract
To develop a suitable biomonitor of metal pollution in watersheds, we examined trends in exposure to nine trace elements in the diet (benthic invertebrates and fish), feathers (n = 104), and feces (n = 14) of an aquatic passerine, the American dipper (Cinclus mexicanus), from the Chilliwack watershed in British Columbia, Canada. We hypothesized that key differences may exist in exposure to metals for resident dippers that occupy the main river year-round and altitudinal migrants that breed on higher elevation tributaries because of differences in prey metal levels between locations or possible differences in diet composition. Metals most commonly detected in dipper feather samples in decreasing order were Zn &gt; Cu &gt; Hg &gt; Se &gt; Pb &gt; Mn &gt; Cd &gt; Al &gt; As. Resident dipper feathers contained significantly higher mean concentrations of mercury (0.64 μg/g dry wt), cadmium (0.19 μg/g dry wt), and copper (10.8 μg/g dry wt) relative to migrants. Mass balance models used to predict daily metal exposure for dippers with different diets and breeding locations within a watershed showed that variation in metal levels primarily was attributed to differences in the proportion offish and invertebrates in the diet of residents and migrants. In comparing predicted metal exposure values to tolerable daily intakes (TDI), we found that most metals were below or within the range of TDI, except selenium, aluminum, and zinc. Other metals, such as cadmium, copper, and arsenic, were only of concern for dippers mainly feeding on insects; mercury was only of concern for dippers consuming high fish diets. The models were useful tools to demonstrate how shifts in diet and breeding location within a single watershed can result in changes in exposure that may be of toxicological significance.
Macroinvertebrate community response to pulse exposure with the insecticide lambda-cyhalothrin using in-stream mesocosms
Authors: Heckmann Lars-Henrik , Friberg Nikolai 
Published: March 2005

Abstract
esticides are constantly beingapplied to agricultural catchments, but little is known abouttheir impact onaquatic biota during natural exposure. In the present study, the impact of the pyrethroid lambda-cyhalothrin was studied in an in-stream mesocosm setup. Twice during the summer of 2002, the natural macroinvertebrate community was exposed in situ to a 30-min pulse of lambda-cyhalothrin. Pyrethroid doses were released through a modified drip set with nominal concentrations of 0.10, 1.00, and 10.0 μg L−1 during the first exposure and 0.05, 0.50, and 5.00 μg L−1 in the second exposure. Before, during, and after exposure, drifting macroinvertebrates were caught in nets. Quantitative benthic samples were taken both before and on two occasions after exposure. Macroinvertebrate drift increased immediately after the pulse exposure, with total drift being significantly higher at all concentrations. Gammarus pulex, various Ephemeroptera, Leuctra sp., and Simuliidae were some of the taxa showing the most pronounced drift response. Structural change in the community was found only at 5.00 and 10.0 μg L−1, and recovery occurred within approximately two weeks. The present study may be valuable in assessing extrapolations based on laboratory results as well as in evaluating pyrethroid impact on natural freshwater environments.
Risk of five polycyclic aromatic hydrocarbons in a terrestrial environment: Influence of data variability
Authors: Fauser Patrik , Thomsen Marianne , Scott-Fordsmand Janeck , Sørensen Peter B. 
Published: March 2005

Abstract
The risk of five different pyrogenic polycyclic aromatic hydrocarbons (P AH) toward two soil-dwelling organisms (i.e., springtail [Folsomia fimetaria] and earthworm [Eisenia veneta]) has been investigated with respect to lethality and reproduction at two soil depths in a typical Danish soil. Predicted environmental concentrations (PECs) are calculated with a model describing diffusion, bulk flow, and microbial degradation. Predicted no-effect concentrations (PNECs) are derived from laboratory experiments performed with nominal soil concentrations in the range from 0 to 300 μg PAH/g dry weight. Risk is estimated through a stochastic approach as well as with the conventional point estimate. The point estimate predicts a potential risk for pyrene, log PEC/PNEC = —0.01, with respectto springtail reproduction at 5 cm soil depth. In all other scenarios, the point-estimate log-ratiosare significantly lower than 0. For the stochastic approach risk is defined when the probability for risk (i.e., the probability for log PEC/PNEC &gt; 0), is larger than 5%. The results show that risk is present only for springtail and in the following five scenarios: For anthracene, the probability for risk with respect to lethality is 12% at 5 cm soil depth, and 17 and 5% with respect to reproduction at 5 and 50 cm soil depth, respectively; for pyrene the probability for risk with respect to reproduction is 49 and 14% at 5 and 50 cm, respectively. The results show that risk cannot be defined unambiguously with the two approaches. The probabilistic approach is less restrictive, and even small probabilities may be used as early-warning indications that risk may be posed under unfavorable circumstances.
Effect of cyclodextrin and transformer oil amendments on the chemical extractability of aged [14C]polychlorinated biphenyl and [14C]polycyclic aromatic hydrocarbon residues in soil
Authors: Doick Kieron J. , Burauel Peter , Jones Kevin C. , Semple Kirk T. 
Published: March 2005

Abstract
Sequestration of hydrophobic organic contaminants (HOCs) in soils limits chemical and biological availability. Concerns exist regarding the long-term stability of sequestered contaminants in the environment, and stability needs to be demonstrated if bioavailability considerations are to be adopted into the risk assessment and remediation of contaminated land. The aim of the present study was to test the short-term influence of two organic amendments on the chemical extractability of HOC residues that had been present in soils for more than 12 years. The amendments investigated were cyclodextrin and transformer oil (a light, nonaqueous phase liquid [LNAPL]). The contaminants investigated were fluoranthene and benzo[a]pyrene in one soil and the polychlorinated biphenyls (PCBs) 28 and 52 in a second soil. The addition of cyclodextrin to the soils did not result in a significant increase in chemical extractability of the residues after a 36-d contact time. The addition of transformer oil resulted in an increase in chemical extractability of the PCBs after a 14-d soil-LNAPL contact time and a further increase after a 36-d contact time. The present study demonstrates that the chemical availability of aged HOCs in soil may be influenced by the presence of other chemicals and has implications for the long-term management of contaminated land.
Apoptosis in Cyclosporin A‐Induced Gingival Overgrowth: A Histological Study
Authors: Alaaddinog͠lu Emine Elif , Karabay Gülten , Bulut Şule , Oduncuog͠lu Füsun Bahar , Özdemir Handan , Bulut Ömer Engin , Çolak Turan 
Published: March 2005

Background: Cyclosporin A (CsA) is known to induce gingival overgrowth. Apoptosis plays a critical role in the regulation of inflammation and the host immune response. The aim of this study was to investigate apoptosis in CsA‐induced gingival enlargement using electron microscopy examination of keratinocytes.Methods: Gingiva specimens were collected from 12 CsA‐treated renal transplant patients with gingival overgrowth and eight healthy controls with gingivitis. Clinical findings (probing depth, gingival index, and plaque index) were compared in the two groups. Histological and ultrastructural features of the specimens were also compared, and extent of keratinocyte apoptosis was scored on a three‐tier scale: 0 = no apoptotic cells; 1 = one or two apoptotic cells; 2 = more than two cells.Results: There were no significant differences between groups with respect to gingiva‐related clinical findings or extent of keratinocyte apoptosis.Conclusions: The results indicate that the extent of keratinocyte apoptosis in the gingiva of kidney recipients with CsA‐induced gingival overgrowth is similar to that observed in inflamed gingiva of healthy individuals. Further studies on apoptosis of different cell types in the presence of CsA should clarify this agent's role in the pathogenesis of drug‐induced gingival enlargement. J Periodontol 2005;76:166‐170.
Histologic Evaluation of Autogenous Connective Tissue and Acellular Dermal Matrix Grafts in Humans
Authors: Cummings Lewis C. , Kaldahl Wayne B. , Allen Edward P. 
Published: March 2005

Background: The clinical success of root coverage with autogenous connective tissue (CT) or acellular dermal matrix (ADM) has been well documented. However, limited histological results of CT grafts have been reported, and a case report of a human block section has been published documenting an ADM graft. The purpose of this study is to document the histological results of CT grafts, ADM grafts, and coronally advanced flaps to cover denuded roots in humans.Methods: This study included four patients previously treatment planned for extractions of three or more anterior teeth. Three teeth in each patient were selected and randomly designated to receive either a CT or ADM graft beneath a coronally advanced flap (tests) or coronally advanced flap alone (control). Six months postoperatively block section extractions were performed and the teeth processed for histologic evaluation with hematoxylin‐eosin and Verhoeff's stains.Results: Histologically, both the CT and ADM were well incorporated within the recipient tissues. New fibroblasts, vascular elements, and collagen were present throughout the ADM, while retention of the transplanted elastic fibers was apparent. No effect on the keratinization or connective tissue organization of the overlying alveolar mucosa was evident with either graft. For both materials, areas of cemental deposition were present within the root notches, the alveolar bone was essentially unaffected, and the attachments to the root surfaces were similar.Conclusion: Although CT and ADM have a slightly different histological appearance, both can successfully be used to cover denuded roots with similar attachments and no adverse healing. J Periodontol 2005;76:178‐186.
EXternal Pelvic REctal SuSpension (Express procedure) for rectal intussusception, with and without rectocele repair
Authors: Williams N S , Dvorkin L S , Giordano P , Scott S M , Huang A , Frye J N R , Allison M E , Lunniss P J 
Published: March 2005

Abstract

Background
The results of conventional treatment for rectal intussusception and rectocele are unpredictable. The aim was to develop a less invasive surgical approach and to evaluate outcome in selected patients.

Methods
Seventeen patients (13 women; median age 47 (range 20–67) years) with rectal evacuatory dysfunction and rectal intussusception, 13 of whom had a rectocele, were selected. The intussusception was corrected by external pelvic suspension of the rectum, using collagen strips attached to the rectal wall and pubis. The rectocele was repaired with a collagen patch. Patients were assessed before and 6 months after surgery by symptom and quality of life questionnaires, anorectal physiological investigation and proctography, and were followed up for a median of 12 months.

Results
Sepsis requiring exploration occurred in two patients but there was no extrusion or need to remove the collagen. Of the 15 patients assessed after surgery, total symptom scores were significantly decreased (P &lt; 0·001) and quality of life scores improved (P &lt; 0·001). Proctographically, the degree of intussusception was improved in ten patients; six patients had normal postoperative proctograms. The rectocele was reduced in size in all patients, and was not demonstrable in eight.

Conclusion
An effective procedure for rectal intussusception and rectocele has been developed in a selected group of patients with marked evacuatory symptoms.