bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of using synthetic sea salts when measuring and modeling copper toxicity in saltwater toxicity tests
Authors: Arnold W. Ray , Cotsifas Jeffrey S. , Winter Anna R. , Klinck Joel S. , Smith D. Scott , Playle Richard C.
Published: April 2007

Synthetic sea salts are often used to adjust the salinity of effluent, ambient, and laboratory water samples to perform toxicity tests with marine and estuarine species. The U.S. Environmental Protection Agency (U.S. EPA) provides guidance on salinity adjustment in its saltwater test guidelines. The U.S. EPA suggests using commercial sea salt brands, such as Forty Fathoms® (now named Crystal Sea Marinemix®, Bioassay Grade), HW Marinemix®, or equivalent salts to adjust sample salinity. Toxicity testing laboratories in Canada and the United States were surveyed to determine synthetic sea salt brand preference. The laboratories (n = 27) reported using four brands: Crystal Sea Marinemix (56%), HW Marinemix (22%), Instant Ocean® (11%), and Tropic Marin® (11%). Saline solutions (30 g/L) of seven synthetic sea salts were analyzed for dissolved copper and dissolved organic carbon (DOC) content. Brands included those listed above plus modified general-purpose salt (modified GP2), Kent Marine®, and Red Sea Salt®. The synthetic sea salts added from <0.1 to 1.2 μg Cu/L to the solution. Solutions of Crystal Sea Marinemix had significantly elevated concentrations of DOC (range = 5.4–6.4 mg C/L, analysis of variance, Tukey, a = 0.05, p < 0.001) while other brands generally contained <1.0 mg C/L. The elevated DOC in Crystal Sea Marinemix was expected to reduce copper toxicity. However, the measured dissolved copper effective concentration 50% (EC50) for Crystal Sea Marinemix was 9.7 μg Cu/L, similar to other tested sea salts. Analysis indicates that the organic matter in Crystal Sea Marinemix differs considerably from that of natural organic matter. On the basis of consistently adding little DOC and little dissolved copper, GP2 and Kent Marine are the best salts to use.
Kinetic model of cadmium accumulation and elimination and metallothionein response in Ruditapes decussatus
Authors: Serafim Angela , Bebianno Maria João
Published: April 2007

The aim of the present study was to determine the response of metallothionein (MT) during Cd accumulation and elimination in different tissues of the estuarine bivalve Ruditapes decussatus exposed to two nominal Cd concentrations (4 and 40 μg/L) for 40 d, followed by a depuration period of 50 d. Cadmium was accumulated in all tissues of R. decussatus at both exposure concentrations, and the accumulation was tissue dependent. Use of the kinetic model showed that in the gills and remaining tissues, Cd was assimilated faster at the beginning of the exposure and decreased with time, possibly limited by the diffusion rate of this metal within the cell. In the digestive gland, however, the Cd was continuously accumulated. This could reflect that the Cd uptake rate is considerably higher than the loss rate and, therefore, that this tissue has a higher capacity to accumulate Cd compared to the other two tissues. Moreover, the application of this kinetic model in the different subcellular fractions showed that the bioconcentration factor was significantly higher in the low-molecular-weight fraction (where MT is found), suggesting that this fraction binds Cd faster, with a high uptake rate (Ku = 32/d), and eliminates this metal more slowly (K1, = 0.005/d). During the depuration phase, MT decreased simultaneously with Cd elimination in all tissues, although with a shorter half-life. In conclusion, the MT response prevented Cd in the tissues of R. decussatus from interfering in the normal clam metabolism; therefore, MT acts as a detoxification mechanism of Cd.
Role of ethylenediaminetetraacetic acid on lead uptake and translocation by tumbleweed (Salsola kali L.)
Authors: de la Rosa Guadalupe , Peralta-Videa Jose R. , Cruz-Jimenez Gustavo , Duarte-Gardea M. , Martinez-Martinez Alejandro , Cano-Aguilera Irene , Sharma Nilesh C. , Sahi Shivendra V. , Gardea-Torresdey Jorge L.
Published: April 2007

Tumbleweed plants (Salsola kali L.) grown in agar and liquid media demonstrated a high capacity to accumulate Pb in their different parts without affecting biomass. Whereas shoot elongation and biomass were not significantly affected by high tissue concentrations of Pb, root growth was significantly affected relative to controls. Roots, stems, and leaves demonstrated Pb concentrations of 31,000, 5,500, and 2,100 mg/kg dry weight, respectively, when plants were grown in the agar medium containing 80 mg Pb/L. Application of ethylenediaminetetraacetic acid (EDTA) to Pb-contaminated media dramatically reduced the total acquisition of Pb from both types of media. However, EDTA significantly increased the translocation of Pb from roots to the aerial parts, as evidenced by a multifold increase (23- and 155-fold for agar and liquid media, respectively) in the translocation concentration factor. The concentration of the antioxidant thiol compounds significantly increased (p < 0.05) in plants grown with uncomplexed Pb treatments relative to control plants. Scanning-electron microscopy and electron dispersive x-ray spectroscopic evaluation of leaf samples demonstrated an interesting pattern of Pb translocation in the presence or absence of EDTA. Large Pb crystals were found across the leaf tissues (palisade, spongy parenchyma, and conducting tissues) in the absence of EDTA. Lead nanoparticles also were seen when plants were grown in Pb-EDTA solution. Ultramicroscopic features of tumbleweed provide clear evidence for the unrestricted conduction of Pb from the root to the aerial parts, and this property makes the plant a good candidate for phytoremediation.
Immunotoxicity of the commercial polybrominated diphenyl ether mixture DE-71 in ranch mink (Mustela vison)
Authors: Martin Pamela A. , Mayne Greg J. , Bursian Steven J. , Tomy Gregg , Palace Vince , Pekarik Cynthia , Smits Judit
Published: April 2007

Polybrominated diphenyl ethers (PBDEs) are persistent, bioaccumulative, organohalogen compounds that are increasing exponentially in the Great Lakes (Canada/USA) biota. The present study was undertaken to examine the immunological effects of a commercial PBDE mixture in ranch mink (Mustela vison). Twenty-week-old mink (n = 10 mink/group) were exposed to 0, 1, 5, or 10 ppm of DE-71 through their diet for eight weeks. The phytohemagglutinin-induced cutaneous reaction, and antibodies specific to keyhole limpet hemocyanin conjugated to dinitrophenol were measured. Liver microsomal ethoxyresorufin-O-deethylase (EROD) activity also was measured. Organs were weighed and spleens were examined histologically. No differences were found in the PHA-induced skin response in exposed mink; mink in the two highest treatments exhibited significant increases in antibody production over control mink. Systemic toxicity was apparent; significant body weight reductions were found in mink exposed to 5 and 10 ppm of DE-71. Exposed mink had significantly larger relative spleen, adrenal, and liver masses than control mink. Spleens of mink exposed to 10 ppm of DE-71 had significantly increased germinal center development and incidence of B-cell hyperplasia. The activity of EROD was induced in all treated mink relative to controls and was positively associated with the liver somatic index. Hematocrit in mink from the two highest exposure groups was significantly lower than control mink. Percentage neutrophils increased and percentage lymphocytes decreased significantly in mink from the higher two dosage groups. Our findings have direct relevance to wild mink in the Great Lakes ecosystem, because mink are top predators of the aquatic food web, providing evidence for the vulnerability of this species to the effects of environmental PBDE mixtures.
Dose verification after topical treatment of alligator (Alligator mississippiensis) eggs
Authors: Muller Jennifer K. , Scarborough Janet E. , Sepúlveda María S. , Casella George , Gross Timothy S. , Borgert Christopher J.
Published: April 2007

Numerous studies have used temperature-dependent sex determination in reptilian eggs to investigate potential developmental effects of exogenously applied substances. However, few studies have measured the dose carried across the eggshell. We report embryonic mortality and internal egg concentrations determined by gas chromatography—mass spectrometry two weeks after exposure of American alligator (Alligator mississippiensis) eggs to chlorinated organic pesticides via injection or topical application. Puncturing the eggshell for injection produced high mortality compared with unpunctured controls; therefore, further evaluation of this method was abandoned. Although higher than controls, mortality was much lower in eggs treated topically than in those injected. Transfer of chemicals across the eggshell was very low, highly variable, and did not correlate with the applied dose after topical application. These results are consistent with previous reports in the literature, casting doubt on whether a reproducible internal dose can be achieved in reptilian eggs by topical treatment.
Topical dose delivery in the reptilian egg treatment model
Authors: Muller Jennifer K. , Gross Timothy S. , Borgert Christopher J.
Published: April 2007

Developing assays to detect endocrine-mediated toxicity from in ovo or in utero exposure is a current challenge in regulatory toxicology. Some species of reptiles exhibiting a unique mode of sex determination, in which the incubation temperature during a critical period determines gonadal sex, have been explored as an in ovo model to screen environmental contaminants for endocrine effects. We critically review published egg-exposure studies and conclude that data regarding the pharmacokinetics of topically applied substances are insufficient to validate dose—response relationships for the effects of chemicals on in ovo endocrine function or gender determination in reptiles. The insufficiencies in these data largely result from methodological failures, including lack of measurement verification, failure to investigate and control extraneous factors affecting the measurements, and lack of independent replication of results. Considerable additional research will be necessary to alleviate these methodological inadequacies. Given the current status of the data, topical treatment of reptilian eggs cannot be considered to be a valid means of establishing causal relationships between chemical treatment and biological outcome.
Biomagnification and polychlorinated biphenyl congener distribution in an aquatic predator-prey, host-parasite system
Authors: Persson Maria E. , Larsson Per , Stenroth Patrik
Published: April 2007

Biomagnification and polychlorinated biphenyl (PCB) congener distribution was examined in a predator-prey, hostparasite system, in which Atlantic salmon (Salmo salar) preyed upon sprat (Sprattus sprattus). Eubothrium crassum was an intestinal parasite in salmon that also “preyed upon” sprat, because the parasites gained access to foodstuffs via the host (salmon) gut. Salmon contained significantly higher concentrations of total PCBs compared to both parasites and prey (sprat), but no difference in PCB concentration was found between sprat and E. crassum. Salmon biomagnified several PCB congeners from their diet (sprat), whereas parasites did not, despite the fact that both salmon and their parasites ingested the same prey. Differences in nutrient uptake mechanisms between the host and their parasites, in addition to the lack of a gastrointestinal tract in the cestode, may explain the lack of biomagnification in E. crassum. No difference was found in PCB congener distribution between parasites, salmon, and sprat, and none of the animal types showed a preference for accumulating more or less lipophilic congeners (congeners with a high or low octanol/water partition coefficient [KOW]). Biomagnification factors for individual congeners in salmon did not increase with KOW; rather, they were constant, as shown by a linear relationship for congener concentration in prey and predator.
Influence of seasonality and exposure on the accumulation and reproductive effects of p,p′-dichlorodiphenyldichloroethane and dieldrin in largemouth bass
Authors: Johnson Kevin G. , Muller Jennifer K. , Price Bertram , Ware Adam , Sepúlveda María S. , Borgert Christopher J. , Gross Timothy S.
Published: April 2007

Two studies investigated the accumulation and reproductive effects of p,p′-dichlorodiphenyldichloroethane (DDE) and dieldrin over 30 or 120 d of oral exposure in captive Florida, USA, largemouth bass (Micropterus salmoides floridanus). The 30-d exposures were conducted during the peak reproductive season, and the 120-d study was conducted to simulate exposure throughout the ovarian cycle. Whole body chemical residue concentrations were similar, regardless of exposure duration, for the medium and high feed concentrations of either chemical; however, the low-dose residue concentrations were much lower, yet similar to natural exposures. No clear dose-response relationships were identified between chemical dose and morphological (length, weight, hepatosomatic index) or reproductive endpoints (sex steroid concentration, gonadosomatic index, percentage of fry hatching). Reproductive parameters were variable within treatment groups, indicating that circulating sex steroids and percent hatch endpoints have high natural variability among fish of the same age and reproductive stage. However, in general there was a decrease in plasma estradiol and 11-ketotestosterone for female and male fish, respectively, that were exposed to dieldrin. Overall, results suggest that exposure throughout ovarian (follicular) development to either DDE or dieldrin alone does not result in the depressed endocrine status and poor reproductive success reported in highly organochlorine pesticide—contaminated environments in Central Florida, USA.
Comparative neurotoxicity of two energetic compounds, hexanitrohexaazaisowurtzitane and hexahydro-1,3,5-trinitro-1,3,5-triazine, in the earthwormEisenia fetida
Authors: Gong Ping , Inouye Laura S. , Perkins Edward J.
Published: April 2007

Hexanitrohexaazaisowurtzitane (CL-20) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), both energetic compounds, share some degree of structural similarity. A noninvasive electrophysiological technique was employed to assess the impacts of acute sublethal exposures on impulse conduction in medial (MGF) and lateral (LGF) giant nerve fiber pathways of the earthworm Eisenia fetida and to evaluate the reversibility of neurotoxic effects. Earthworms were exposed to either 0.02 to 2.15 μg/cm2 of CL-20 or 0.04 to 5.35 μg/cm2 of RDX, for 1 to 14 d, on moistened filter paper. Conduction velocities of MGF and LGF were recorded on a digital oscilloscope before and after exposure. Results indicate that at exposure levels as low as 0.02 μg/cm2 of CL-20 or 0.21 μg/cm2 of RDX, worms exhibited physiological impacts such as retardation, stiffness, and body shrink. Both MGF and LGF conduction velocities were negatively correlated with increasing doses of CL-20 or RDX. However, such neurotoxic effects were alleviated or even eliminated within a few days after exposed worms were transferred to an uncontaminated environment, indicating that the neurotoxicity is reversible even after 6-d exposure. The CL-20 is more potent than RDX, which is consistent with previous studies on lethality, growth, and reproduction endpoints in soil oligochaetes.
Characterization of polycyclic aromatic hydrocarbon bioavailability in estuarine sediments using thin-film extraction
Authors: Golding Christopher J. , Gobas Frank A.P.C. , Birch Gavin F.
Published: April 2007

It is well documented that the bioavailability of hydrophobic organic chemicals (HOCs) can vary substantially among sediments. This makes risk assessments based on total sediment concentrations problematic. The present study investigates the application of thin-film solid-phase extraction to measure bioavailable concentrations of phenanthrene in estuarine sediment by comparing concentrations of phenanthrene in the amphipod Corophium colo and in thin ethylene/vinyl acetate films at different concentrations in three geochemically different sediments. For all sediment types, concentrations of phenanthrene in sediments and thin films followed linear relationships, indicating first-order exchange kinetics. Organism/thin-film concentration ratios did not vary systematically among sediment types but dropped significantly with increasing phenanthrene concentration in the sediments. While at low phenanthrene concentrations in the sediment fugacities of phenanthrene in the amphipods approached the fugacities in the thin films, they were significantly lower than those in the sediments at higher concentrations. While phenanthrene concentrations in the three sediment types were identical, biota sediment accumulation factors and concentrations in amphipods and thin films were consistently lower in sediments enriched with black carbon than in sediments with sedimentary organic matter bearing a more diagenetic organic signature. It is concluded that, for the range of concentrations tested, thin-film solid-phase extraction can be a useful tool in the characterization of differences in bioavailability of HOCs among sediment types.
Gill metal binding and stress gene transcription in brown trout (Salmo trutta) exposed to metal environments: The effect of pre-exposure in natural populations
Authors: Hansen Bjørn Henrik , Garmo Øyvind A. , Olsvik PÅl A. , Andersen Rolf A.
Published: April 2007

Brown trout (Salmo trutta) from two native populations from the Røros area in Central Norway, acclimated in mining-affected habitats to different levels of Cd/Zn and Cu, together with trout from a nearby unaffected river (reference) were transferred to a nearby lake with higher levels of Cu, Cd, and Zn than those in their respective native rivers. This experiment was conducted to gain information about the underlying resistance mechanisms developed in fish exposed to metal environments. The focus was on gill metal accumulation and transcription of the metal-responsive stress genes metallothionein-A (MT-A), Cu/Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and heat shock protein 70 (HSP-70). The only shared response shown between the three groups after transfer were Cu accumulation and MT-A induction. The Cu-acclimated trout produced mucus to reduce the uptake of Cu into the gills. The MT-A levels were highest in the Cd/Zn-acclimated trout both before and after transfer. Before transfer, antioxidant transcription (SOD and GPx) was higher in gills of Cu-acclimated compared to the Cd/Zn-acclimated trout, but increased transcription of antioxidant stress genes was observed after transfer in both metal-acclimated groups. The metal-acclimated trout groups also showed an increase in the transcription of HSP-70. Compared to the reference population not previously exposed to metals, stress gene transcription increased faster in the metal-acclimated populations. The exception was induction of CAT, which appeared to be depressed after transfer in Cd/Zn-acclimated trout. The data indicate that acclimation to chronic metal exposure involves different strategies to cope with different metals and that these strategies involve both physiological mechanisms (mucus production) as well as metal-related stress gene transcription.
Bioavailability of polycyclic aromatic hydrocarbons sequestered in sediment: Microbial study and model prediction
Authors: Beckles Denise M. , Chen Wei , Hughes Joseph B.
Published: April 2007

In field studies and remediation projects, contaminants persist in soil and sediment much longer than would be estimated based on contaminant physical and chemical properties; such observations indicate that a fraction of contaminants in soil/sediment is much less available to the degrading microorganisms or chemical reagents. Many researchers attribute this reduced availability/bioavailability to the sequestration (also referred to as resistant desorption or desorption hysteresis) of contaminants in soil/sediment. In the present research, desorption and bioavailability of naphthalene, phenanthrene, and fluoranthene were studied to evaluate the impact of sequestration on the biodegradability of these three polycyclic aromatic hydrocarbons (PAHs). Experimental results indicate that only desorbed PAHs are bioavailable and that the bioavailability of sequestered PAHs could be well predicted with a modified bioavailability model, which uses a biphasic desorption model to replace the conventional adsorption/desorption model. Findings in the present study might have important implications for site remediation: After the initial stage of remediation (i.e., after the readily desorbable fraction of contaminants is removed from soil/sediment), desorption of sequestered contaminants becomes the rate-limiting step of remediation. In this stage, the availability of contaminants is so low that even aggressive remediation would have little effect on overall mass reduction. Thus, a more cost-effective approach for site remediation might consist of an initial aggressive treatment followed by plume control, such as monitored natural attenuation.
Soil biogeochemical toxicity end points for sub-Antarctic islands contaminated with petroleum hydrocarbons
Authors: Schafer Alexis Nadine , Snape Ian , Siciliano Steven Douglas
Published: April 2007

Sub-Antarctic islands have been subjected to petroleum hydrocarbon spills, yet no information is available regarding the toxicity of petroleum hydrocarbons to these subpolar soils. The purpose of the present study was to identify soil biogeochemical toxicity end points for petroleum hydrocarbon contamination in sub-Antarctic soil. Soil from Macquarie Island, a sub-Antarctic island south of Australia, was collected and exposed to 10 concentrations of Special Antarctic Blend (SAB) diesel fuel, ranging from 0 to 50,000 mg fuel/kg soil, for a 21-d period. The sensitivity of nitrification, denitrification, carbohydrate utilization, and total soil respiration to SAB fuel was assessed. Potential nitrification activity was the most sensitive indicator of SAB contamination assessed for nitrogen cycling, with an IC20 (concentration that results in a 20% change from the control response) of 190 mg fuel/kg soil. Potential denitrification activity was not as sensitive to SAB contamination, with an IC20 of 950 mg fuel/kg soil for nitrous oxide production. Nitrous oxide consumption was unaffected by SAB contamination. Carbohydrate utilization (respiration caused by sucrose) was a more sensitive indicator (IC20, 16 mg fuel/kg soil) of SAB contamination than total respiration (IC20, 220 mg fuel/kg soil). However, total soil respiration was a more responsive measurement end point, increasing soil respiration over a 72-h period by 17 mg of CO2, compared to a change of only 2.1 mg of CO2 for carbohydrate utilization. Our results indicate that IC20s varied between 16 to 950 mg fuel/kg soil for Macquarie Island soil spiked with SAB diesel fuel. These results indicate that current cleanup levels derived from temperate zones may be too liberal for soil contamination in sub-Antarctic islands.
Causes of water toxicity toHyalella aztecain the New River, California, USA
Authors: Phillips Bryn M. , Anderson Brian S. , Hunt John W. , Tjeerdema Ron S. , Carpio-Obeso Maria , Connor Valerie
Published: April 2007

The New River (CA, USA) was created in 1905 to 1907 when the Colorado River washed out diversionary works and flowed into the Salton Basin, creating the Salton Sea. Approximately 70% of the river's current flow is agricultural wastewater from the Imperial Valley. The river is contaminated with pesticides, industrial organic chemicals, metals, nutrients, bacteria, and silt. Monitoring for the State of California Surface Water Ambient Monitoring Program has indicated persistent water column toxicity to the epibenthic amphipod Hyalella azteca. Four toxicity identification evaluations (TIEs), along with chemical analyses, were performed, and the results indicated multiple and varying causes of toxicity. The first two TIEs characterized the causes of toxicity as a combination of metals and organics, but only the second sample contained enough total copper to contribute to toxicity. The third TIE used an emerging method for characterizing and identifying toxicity caused by pyrethroid pesticides. This TIE characterized organics as the cause of toxicity, and a carboxylesterase enzyme treatment further identified the cause of toxicity as pyrethroids. The final TIE used the enzyme and Phase II procedures to identify cypermethrin as the cause of toxicity. The TIE results demonstrate the evolving causes of toxicity in the New River and should assist regulators with implementing the total maximum daily load process for pesticides, particularly pyrethroids. Further research will determine if pyrethroids and other New River contaminants are having an impact on the Salton Sea.
The relationship between cholinesterase inhibition and two types of swimming performance in chlorpyrifos-exposed coho salmon (Oncorhynchus kisutch)
Authors: Tierney Keith , Casselman Matt , Takeda Scott , Farrell Tony , Kennedy Chris
Published: April 2007

Brain acetylcholinesterase (AChE) activity was evaluated after two different swimming tests in coho salmon (Oncorhynchus kisutch; 238 ± 5 g) given 96-h exposures to 0, 5, 10, 20, or 40 μg/L of chlorpyrifos. Brain AChE activity decreased in a concentration-dependent manner (AChE activities were 81.8, 52.2, 37.3, and 21.3% of control for the 5, 10, 20, and 40 μg/L exposures, respectively), whereas swimming performance was impaired after a threshold of AChE impairment was reached. Specifically, for swimming performance (Ucrit) measured using the established ramp-Ucrit test (duration, 152 ± 8 min), this threshold occurred with AChE activity of 68.5% ± 18.1% of control. For a rapid acceleration test (UΔV, where V represents velocity; 27.6 ± 0.8 min), this value was 52.6% ± 15.4% of control. Both swim protocols resulted in similar maximum swim speeds (control ramp-Ucrit and UΔV values of 3.44 ± 0.09 and 3.71 ± 0.13 body lengths/s, respectively), and performance was significantly reduced after 20 and 40 μg/L exposures in both groups (ramp-Ucrit values: 86.4 and 83.6 %, respectively, of control; UΔV values: 85.2 and 77.8%, rsepectively, of control). Although both tests yielded similar swim speeds, postexercise plasma lactate concentrations were greater for the UΔV test (11.3 ± 0.6 vs 8.6 ± 0.5 mmol/L), indicating a greater anaerobic effort. This increase was exaggerated after 10 μg/L of chlorpyrifos (14.6 ± 1.3 mmol/L), indicating that anaerobic muscle was used to attain the same speed. Given the threshold relationship between AChE inhibition and swimming performance, coho salmon appear able to maintain integrated swimming activity despite significant impairment of an underlying neurological control mechanism.
Environmentally relevant concentrations of ethynylestradiol cause female-biased sex ratios in Xenopus tropicalis and Rana temporaria
Authors: Pettersson Irina , Berg Cecilia
Published: April 2007

The susceptibility of Xenopus (Silurana) tropicalis and Rana temporaria to ethynylestradiol (EE2), a potent estrogenic pharmaceutical and environmental pollutant, was investigated. Larval EE2 exposure caused female-biased sex ratios at concentrations as low as 0.06 nM, which is comparable to levels found in the environment. The susceptibility of the two frog species to EE2 was comparable, supporting the use of X. tropicalis as a model organism for research on developmental reproductive toxicity of estrogenic pollutants.
Developmental toxicity in zebrafish (Danio rerio) embryos after exposure to manufactured nanomaterials: Buckminsterfullerene aggregates (nC60) and fullerol
Authors: Zhu Xiaoshan , Zhu Lin , Li Yan , Duan Zhenghua , Chen Wei , Alvarez Pedro J.J.
Published: April 2007

The present paper summarizes, to our knowledge, the first study regarding the developmental toxicity of stable buck-minsterfullerene aggregates suspended in water (nC60) using zebrafish (Danio rerio) as a vertebrate model. Zebrafish embryo survival, hatching rate, heartbeat, and pericardial edema were noted and described within 96 h of exposure. Fullerol (a hydroxylated C60 derivative, C60(OH)16–18) at 50 mg/L did not exert toxicity to zebrafish embryos. In contrast, nC60 at 1.5 mg/L delayed zebrafish embryo and larval development, decreased survival and hatching rates, and caused pericardial edema. Toxicity was mitigated by adding an antioxidant (glutathione), which suggests that a free radical—induced mechanism or another form of oxidative stress played a role in developmental toxicity.
From the Outside In: Angela Merkel as Opposition Leader, 2000-2005
Authors: Clemens Clay
Published: April 2007

As chair of the CDU in 2000, and of its joint Bundestag caucus with the CSU in 2002, Angela Merkel was the fist woman and fist easterner to head a major German party; she had risen as a protege of Helmut Kohl, but breaking with him over his financial improprieties vaulted her into power. These features of her biography made her leadership unconventional. So too did her style, characterized by interpersonal reserve and lack of charisma. Merkel's views on cultural issues and economic policy-in particular, reform of the welfare state-were more liberal than those of her Union's mainstream. Finally, her resources within the CDU/CSU were limited to a loose network of younger outsiders, who helped sustain her against rivals at the Land level. While Merkel survived a poor CDU/CSU election in 2005 to become chancellor, her time as opposition leader suggested that she would struggle in that role too, yet also served as a caution against underrating her.
How the Federal Republic Became an Immigration Country: Norms, Politics and the Failure of West Germany's Guest Worker System
Authors: Triadafilopoulos Triadafilos , Schönwälder Karen
Published: April 2007

With the passage of a new citizenship law in 1999 and the so-called

Zuwanderungsgesetz (Migration Law) of 2004, contemporary Germany

has gone a long way toward acknowledging its status as an immigration

country (Einwanderungsland). Yet, Germany is still regarded by

many as a “reluctant” land of immigration, different than traditional

immigration countries such as Canada, the United States, and Australia.

It owes this image to the fact that many of today’s “immigrants”

were in fact “guests,” invited to work in the Federal Republic

in the 1950s, 1960s and 1970s and expected to leave when they were

no longer needed. Migration was meant to be a temporary measure,

to stoke the engine of the Economic Miracle but not fundamentally

alter German society. The question, then, is how did these “guest

workers” become immigrants? Why did the Federal Republic

become an immigration country?
The Environmental State and Informational Governance
Authors: Mol Arthur P.J.
Published: April 2007

This paper aims to understand and illustrate how and to what extent the increasing role and importance of information, informational processes, and information technologies have changed the environmental policies and politics of state institutions. More specifically, how have states tried to find answers to the dilemmas resulting from a growing centrality of informational processes in environmental governance? As such, the paper sets out the contours of what can be labeled informational governance on the environment.
A Density Functional Theory Study of the Stille Cross‐Coupling via Associative Transmetalation. The Role of Ligands and Coordinating Solvents
Authors: Faza Rosana Álvarez Olalla Nieto , de Lera Angel R. , Cárdenas Diego J.
Published: April 2007

An associative mechanism has been computationally characterized for the Stille cross‐coupling of vinyl bromide and trimethylvinylstannane catalyzed by PdL2 (L=PMe3, AsMe3) with or without dimethylformamide as coordinating ligand. All the species along the catalytic cycles that start from both the cis‐ and the trans‐PdL(Y)(vinyl)Br complexes (Y=L or S; L=PMe3, AsMe3 or PH3; S=DMF) have been located in the gas phase and in the presence of polar solvents. Computations support the central role of species trans‐PdL(DMF)(vinyl)Br which react by ligand dissociation and stannane coordination in the rate‐limiting transmetalation step via a puckered four‐coordinate (at palladium) transition state comprised of Pd, Br, Sn and sp2 C atoms. A donating solvent may enter the catalytic cycle assisting isomerization of cis‐PdL2(vinyl)Br to trans‐PdL(DMF)(vinyl)Br complexes via a pentacoordinate square pyramidal Pd intermediate. In keeping with experimental observations, the activation energies of the catalytic cycles with arsines as Pd ligands are lower than those with phosphines. Polytopal rearrangements from the three‐coordinate T‐shaped Pd complexes resulting from transmetalation account for the isomerization and the CC bond formation on the reductive elimination step.
Imidazole and Imidazoline Derivatives as N‐Donor Ligands for Palladium‐Catalyzed Mizoroki–Heck Reaction
Authors: Haneda Satoshi , Ueba Chigusa , Eda Kazuo , Hayashi Masahiko
Published: April 2007

Imidazole and imidazoline (dihydroimidazole) derivatives can serve as efficient and simple ligands for the palladium‐catalyzed Mizoroki–Heck reaction. Among the imidazole and imidazoline derivatives in our investigations, the 2‐methylimidazoline‐palladium(II) chloride complex exhibited the highest catalytic activity.
A Simple Approach to Unsymmetric Atropoisomeric Bipyridine N,N′‐Dioxides and Their Application in Enantioselective Allylation of Aldehydes
Authors: Hrdina Radim , Valterová Irena , Hodačová Jana , Císařová Ivana , Kotora Martin
Published: April 2007

The [2+2+2] cyclotrimerization of 1‐isoquinolinyl‐1,7‐octadiyne with benzonitrile catalyzed by CpCo(CO)2 opened a new pathway for a synthesis of unsymmetrical axially chiral bipyridine N,N′‐dioxides. The N,N′‐dioxide 3a was found to be highly catalytically active and enantioselective for the asymmetric allylation of aldehydes with allyltrichlorosilane. The allylation took place with even 1 % of the catalyst with an enantioselectivity up to 87 % ee.
An Efficient Rhodium‐Catalyzed Double Hydroaminocarbonylation of Alkynes with Carbon Monoxide and Amines Affording 1,4‐Diamide Derivatives
Authors: Huang Qiufeng , Hua Ruimao
Published: April 2007

The hydroaminocarbonylation of terminal alkynes with carbon monoxide and pyrrolidine or piperidine catalyzed by rhodium complexes affords 1,4‐diamide derivatives in good to high yields.
Towards a Greener Epoxidation Method: Use of Water‐Surfactant Media and Catalyst Recycling in the Platinum‐Catalyzed Asymmetric Epoxidation of Terminal Alkenes with Hydrogen Peroxide
Authors: Colladon Marco , Scarso Alessandro , Strukul Giorgio
Published: April 2007

Remarkable improvements in enantioselectivity as well as recycle were observed in the catalytic asymmetric epoxidation of terminal alkenes with a chiral, electron‐poor platinum(II) catalyst with hydrogen peroxide as terminal oxidant in water‐surfactant media.
Hydrogen sulfide poisonings in hot‐spring reservoir cleaning: Two case reports
Authors: Deng Jou‐Fang , Chang Shi‐Chuan
Published: April 2007

The potential hazards to maintenance personnel cleaning hot‐spring reservoirs are reported following two severe and unusual episodes of acute hydrogen sulfide poisoning involving seven workers. In the first episode, five victims lost consciousness immediately after climbing down a manhole to the bottom of a reservoir disregarding a strong odor of rotten eggs. One of them died immediately. Of the four who lived, three developed hemorrhagic keratoconjunctivitis and aspiration pneumonia, but no sequelae were observed 2 years later. In the second episode, two workers had been cleaning the reservoir for about 2 hours when one collapsed and his companion went to seek help. Both died of acute respiratory distress syndrome due to pulmonary edema within 12 hours. Since hot‐spring bathing is a popular recreation in Taiwan, other accidents of hydrogen sulfide poisoning may have occurred but have not been reported. Such clinical information is helpful to enable regulators to initiate proper precautions to safeguard those workers involved.
Hippuric acid and ortho‐cresol as biological indicators of occupational exposure to toluene
Authors: de Rosa E. , Bartolucci G. B. , Sigon M. , Callegaro R. , Perbellini L. , Brugnone F.
Published: April 2007

Industrial exposure to toluene was studied in a group of 18 subjects working in a printing plant, exposed only to this solvent. Environmental monitoring was carried out using personal samplers for the whole work‐shift. Urine samples were collected for the determination of hippuric acid and ortho(o)‐cresol before toluene exposure, at the end of the work‐shift, and 5, 9, and 17 h after the end of the work‐shift. The values of two metabolites in all the urinary samples were corrected for g creatinine and specific gravity (1.024).

Toluene time weighted average (TWA) concentrations ranged from 51 to 221 mg/m3 (7‐h samples; two samplings lasting 3.5 h each). Urinary hippuric acid and o‐cresol values at the end of the work‐shift were significantly higher than the prework‐shift values.

Both hippuricuria and o‐cresoluria end‐of‐work‐shift values, corrected for creatinine and specific gravity, were significantly related to the mean daily environmental concentration of toluene, the correlation being weaker for o‐cresol. Correlation coefficients were 0.88 and 0.84 for hippuric acid and 0.63 and 0.62 for o‐cresol after correction for creatinine and specific gravity, respectively. No significant relationship was observed between environmental exposure and the values of the two urinary metabolites 5, 9, and 17 h after the end of the work‐shift.

Extrapolated values from the linear regression analysis at 375 mg/m3 were in good agreement with the biological exposure index (BEI) suggested by ACGIH for hippuric acid.

We conclude that determination of hippuric acid in urine samples collected at the end of the work‐shift can be used for routine biological monitoring of exposure to toluene, even at low levels. O‐cresol seems to be a less reliable indicator of toluene exposure.
Respiratory effects and dust exposures in hog confinement farming
Authors: Holness D. Linn , O'Blenis E. Lee , Sass‐Kortsak Andrea , Pilger Charles , Nethercott James R.
Published: April 2007

Fifty‐three hog confinement farmers and 43 control farmers were studied. Pulmonary function, total and respirable personal dust levels, and responses to a health status questionnaire were obtained for all farmers.

The hog farmers' total and respirable personal dust exposures were significantly higher than the respective levels of the control farmers. Higher dust levels were associated with the use of floor (scatter) feeding, indoor feed grinding, and the use of high moisture corn feed.

Pork producers reported respiratory symptoms significantly more often than controls. Lung function did not differ between the two groups of farmers, nor could dust exposure levels be related to lung function.
Increased chromium and nickel content in lung tissue and bronchial carcinoma
Authors: Kollmeier Heinrich , Seemann Jörg W. , Müller Klaus‐Michael , Rothe Günter , Wittig Peter , Schejbal Vladimir B.
Published: April 2007

In 25 random autopsies, chromium (Cr) and nickel (Ni) in lung tissue and regional lymph nodes were analysed by means of flameless atomic absorption spectrometry (AAS). The subjects originate from Bochum in the Ruhr District, which is defined as a particular pollution area with locally high Cr and Ni emissions. The subjects examined from Bochum (BO) and vicinity have Cr and Ni concentrations about 5 and 6 times higher than those in a previous series form Münster (MS) and vicinity (outside the particular pollution area), which is used for comparison purposes. BO and MS data showed an age‐dependent increase of chromium and nickel in the lung, and in both data sets as well as in the combined, the Cr and Ni values showed extremely high correlations (r > 0.9). The Cr and Ni concentrations (BO) in lung (3.47 ± 2.53 μg Cr/g, 1.09 ± 1.43 μg Ni/g dry weight) and lymph node tissue (6.30 ± 3.72 μg Cr/g, 1.00 ± 0.58 μg Ni/g dry weight) do not show any correlation. The BO data contained four cases of bronchial carcinoma (all male), three of which showed pulmonary Cr and Ni concentrations that lie clearly above the predicted level. One case of bronchial carcinoma had extremely high Cr and Ni values; an occupational exposure as dental laboratory technician is taken into consideration.
High vascular tone but no obliterative lesions in vibration white fingers
Authors: Ekenvall Lena , Lindblad Lars Erik , Bevegård Sture , Etzell Britt‐Marie
Published: April 2007

To study if obliterative lesions in digital arteries are relevant as the pathogenic factor in vibration white finger, finger blood flow was measured in 15 subjects with advanced symptoms and in 15 controls by venous occlusion plethysmography before and after vasodilation. Before vasodilation, the subjects had lower temperature, blood flow, and peak blood flow after arterial occlusion in the fingers than did the controls, while venous tone was increased. In addition, after sympathicolysis, finger blood flow was lower in the study than in the control group, but there was no difference in peak blood flow after arterial occlusion or in venous tone. The results indicate that the subjects have a high vascular tone causing a reduction in blood flow during submaximal flow conditions. Obliterative organic lesions in finger arteries do not seem to be present, since the “maximal” flow values of the subjects are similar to those of the controls.
Problems in establishing norm values for nickel and chromium concentrations in human pulmonary tissue
Authors: Raithel H. J. , Ebner G. , Schaller K. H. , Schellmann B. , Valentin H.
Published: April 2007

In 15 random autopsies, nickel (Ni) and chromium (Cr) were determined quantitatively by atomic absorption spectrometry (AAS) in human lung tissue to evaluate norm values. None of the deceased persons had had an occupational exposure to Cr or Ni or their compounds. In all, 22 tissue samples were taken from each lung at specific topographical anatomical locations. The analytical procedure is described in detail.

The results showed substantial variation in concentrations both within a single lung and also between individuals. Median values found were 204 ng/g for Cr and 25.6 ng/g for Ni. Topographical concentrations of Cr and Ni were 1.3–1.9 times higher in the upper lung areas.

In view of the variability in metal concentration, analysis of only one part of lung tissue is not sufficient for determining the content of the entire lung.

The evaluation of norm values is an important precondition for appraisal of Cr and Ni accumulation in human pulmonary tissue that may be due to occupational exposure.
Proportionate mortality ratio analysis of automobile mechanics and gasoline service station workers in New Hampshire
Authors: Schwartz Eugene
Published: April 2007

A proportionate mortality ratio (PMR) analysis of all deaths recorded from 1975 to 1985 among New Hampshire white male residents (age 20 years or older) was performed using death certificate information. Among automobile mechanics, the analysis revealed increases in mortality from leukemia (PMR = 178, N = 6); cancers of the oral cavity (PMR = 163, N = 4), lung (PMR = 112, N = 36), bladder (PMR = 169, N = 5), rectum (PMR = 182, N = 4), and lymphatic tissues (PMR = 200, N = 6); and cirrhosis of the liver (PMR = 140, N = 13) and suicide (PMR = 177, N = 22; p < 0.05). Workers in the gasoline service station industry experienced a leukemia mortality excess (PMR = 328, N = 3; p < 0.05) as well as increases in deaths from suicide (PMR = 162, N = 4), emphysema (PMR = 245, N = 4), and mental and psychoneurotic conditions (PMR = 394, N = 3). These workers are potentially exposed to a variety of substances including gasoline vapor, benzene, solvents, lubricating oils and greases, and asbestos (from brake and clutch repair) as well as welding fumes and car and truck exhaust. Despite limitations regarding the small number of deaths and methodologic constraints, the results of this analysis suggest that one or more of the exposures experienced by these workers poses a significant carcinogenic risk. More definitive epidemiologic studies are required to determine if the leukemia excess is associated with exposure to benzene, gasoline, or other workplace substances.
Historic cohort study in montreal's fur industry
Authors: Guay Danielle , Siemiatycki Jack
Published: April 2007

A historic cohort mortality study was carried out among two groups of male workers in the Montreal fur industry: 263 dressers and dyers and 599 fur garment manufacturers. The first group is exposed to a very wide variety of chemicals used in tanning, cleaning, and dyeing fur, including substances considered to be carcinogenic and/or mutagenic. The second group is exposed to residue from the dressing and dyeing stage and to respirable fur dust. The cohorts consisted of all active members of two unions as of January 1, 1966. The mean age of the workers was 43.2 and the mean number of years since first employment 14.1. The follow‐up period was from January 1, 1966, to December 31, 1981; 95% of the workers were successfully traced. Observed deaths were compared with those expected based on mortality rates of the population of metropolitan Montreal. Standardized mortality ratios (SMRs) for the manufacturers were significantly low, probably because of the ethnic composition of the cohort and a healthy worker effect. SMRs for the dressers and dyers were also low, but not as low as for the manufacturers. When attention was restricted to the French Canadians in the cohort, the observed deaths were close to the expected; there was a noteworthy excess of colorectal cancer (four observed, 0.8 expected) for dressers and dyers. Apart from this weak suggestive evidence, the results did not indicate any excess mortality risks in the fur industry. However, because of the relatively small number of expected and observed deaths in the cohort and especially among the heavily exposed dressers and dyers, the confidence intervals around SMR estimates were wide and excess risks cannot be ruled out.
Assessing color vision loss among solvent‐exposed workers
Authors: Mergler Donna , Blain Lucie
Published: April 2007

Acquired color vision loss has been associated with exposure to organic solvents in the workplace. However, not all tests of chromatic discrimination loss are designed to detect acquired, as opposed to congenital, loss. The Lanthony D‐15 desaturated panel (D‐15‐d), a simple 15 cap color arrangement test, designed to identify mild acquired dyschro‐matopsia, can be administered rapidly in the field, under standard conditions. The objective of the present study was to evaluate the D‐15‐d among 23 solvent‐exposed workers of a paint manufacturing plant, by comparing the results obtained with the D‐15‐d to those obtained with the Farnsworth‐Munsell 100 Hue (FM‐100), a highly sensitive measure of color vision loss. The D‐15‐d revealed a significantly higher prevalence of dyschromatopsia among the ten highly exposed workers (80%) as compared to the 13 moderately exposed workers (30.8%); FM‐100 results revealed one false positive. All dyschromatopic workers presented blue‐yellow loss; the FM‐100 detected eight complex patterns, while the D‐15‐d identified 5. Comparison of D‐15‐d and FM‐100 scores were highly correlated (corr. coeff. 0.87; p < 0.001). Multiple regression analyses showed both scores to be significantly related to age and exposure level. The findings of this study indicate that the D‐15‐d is an adequate instrument for field study batteries. However, the FM‐100 should be used for more detailed assessment.