bluuebunny/crossref_metadata_2025 huggingface dataset:
Desorption kinetics of chlorobenzenes, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls: Sediment extraction with Tenax® and effects of contact time and solute hydrophobicity
Authors: Cornelissen Gerard , van Noort Paul C M , Govers Harrie A J
Published: March 2010

A technique using Tenax TA® beads as “sink” for desorbed solute was employed to measure the kinetics of desorption of chlorobenzenes, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons from laboratory-contaminated sediment. First-order rate constants of rapid and slow desorption were in the order of 10−1/h and 10−3/h, respectively. The rate constants of slow desorption correlate well with the molecular volumes of the compounds used and decrease between 2 and 34 d of equilibration. Slowly desorbing fractions increase with both increasing solute hydrophobicity and increasing equilibration time.
Estimating total body residues and baseline toxicity of complex organic mixtures in effluents and surface waters
Authors: Van Loon Willem M G M , Verwoerd Marcel E , Wijnker Femke G , van Leeuwen Cees J , van Duyn Piet , van deGuchte Cees , Hermens Joop L M
Published: March 2010

Recently, a new procedure was developed to estimate total body residues (TBRs) in biota after exposure to complex mixtures of organic chemicals in water. The procedure is based on a simulation of bioconcentration using a hydrophobic phase and on the measurement of total molar concentrations on this hydrophobic phase via vapor pressure osmometry and gas chromatography–mass spectrometry. In this paper, the results of the application of this procedure to effluents and surface water are presented. Estimated TBRs (TBRests) give information on the potential total bioaccumulation of complex mixtures. Moreover, using these estimated total body burdens, baseline toxicity effects can be predicted, including the contributions of chemicals with specific modes of action to the overall baseline toxicity. The advantage of the parameter TBRest is that it determines total molar concentrations of organic chemicals, including those chemicals that are usually not measured because they cannot be identified or because their concentrations are below the detection limits of individual compounds.
The uptake, distribution and metabolism of benzo[a]pyrene in coho salmon (Oncorhynchus kisutch) during the parr-smolt transformation
Authors: Lemke M Anna , Kennedy Christopher J
Published: March 2010

Benzo[a]pyrene (BaP) uptake, distribution, and metabolism patterns were investigated from February to June during the transformation of freshwater coho salmon (Oncorhynchus kisutch) parr to smolts. At a BaP concentration of 5 μg/L, uptake rates increased significantly from 0.01 ± 0.000 μg/g/h in February to 0.04 ± 0.003 μg/g/h in May and declined to 0.035 ± 0.004 μg/g/h in June. Following a 24-h exposure to BaP, the highest percent of body burden of BaP was found in the liver, gills, skin, and bile. The proportion of BaP in the liver and gills increased in fish from February to May and declined in June, whereas the proportion of BaP in the bile continued to rise until June when it reached a maximum of 49% of the body burden. The percent body burden of BaP in tissues such as the stomach, intestine, visceral fat, muscle, and brain did not show significant changes through the duration of the study. An analysis of bile suggests that both coho salmon parr and smolts are capable of metabolizing BaP via phase I and II biotransformation reactions to glucuronide, sulfate, and other conjugated metabolites. No significant changes occurred in the proportions of metabolite classes during the parr–smolt transformation process.
Distribution of metals and accumulation of lead by different tissues in the freshwater snail Lymnaea stagnalis (L.)
Authors: Pyatt F Brian , Pyatt Andrea J , Pentreath Vic W
Published: March 2010

The concentrations of several metals in different body tissues of the freshwater snail Lymnaea stagnalis (L.), collected from an uncontaminated environment, were measured by electron probe X-ray microanalysis. Significant concentrations of the potentially toxic elements manganese, titanium, and copper were detected in all tissues, although they were not detectable in the water sampled at collection; bioaccumulation is thus evidenced. Highest concentrations of manganese and copper were present in the shell, while highest concentrations of titanium were present in the head and foot. Experimental snails were continuously exposed to lead chloride (lead at 5 ppm) for an experimental period of 3 weeks. Both elements were accumulated to different extents by the snail tissues but with high concentrations again in the head of the animals, and chloride also in the visceral hump. No significant alterations in the distribution of the other elements measured were observed in the lead chloride-exposed animals.
Effects of air pollution on cell membrane integrity, spectral reflectance and metal and sulfur concentrations in lichens
Authors: Garty Jacob , Cohen Yehudith , Kloog Nehama , Karnieli Arnon
Published: March 2010

The fruticose lichen Ramalina duriaei is generally considered to be sensitive to air pollution. In the present study we sought to determine whether thalli of this lichen collected in a remote unpolluted site (the HaZorea Forest, northeast Israel) and transplanted to the Ashdod region (southwest Israel) could provide information on the quality of the air in this area. For this purpose, the concentrations of Pb, Cu, Cd, Ni, Mn, Fe, S, Ca, Mg, Na, and K were determined in in situ thalli collected in the HaZorea Forest in March 1993 and in in situ and transplanted thalli retrieved in June 1993. The concentration of these elements in R. duriaei thalli was analyzed in comparison with physiological parameters such as the integrity of cell membranes, chlorophyll content, and alterations in reflectance responses from lichen thalli. Thalli transplanted to several industrial sites in the town of Ashdod for a period of 100 d accumulated high concentrations of Pb, Cd, Ni, Fe, S, Mg, Na, Ca, and K. The concentration of S in thalli transplanted to the Ashdod region was found to correlate with damage caused to cell membranes and showed an inverse correlation with the chlorophyll content and with the reflectance response of the lichen. The electrical conductivity values corresponding to membrane integrity in the lichen thallus showed an inverse correlation with the ratio of chlorophyll a to pheophytin a, indicating the integrity of the photobiontic chlorophyll and with normalized-difference vegetation index values corresponding to the reflectance response of the thallus. The chlorophyll integrity correlated with the reflectance response. Magnesium accumulated in the lichen thalli in dusty sites and was found to correlate with damage caused to membranes.
Modulation of 2′-5′oligoadenylate synthetase by environmental stress in the marine sponge Geodia cydonium
Authors: Schröder Heinz C , Wiens Matthias , Kuusksalu Anne , Kelve Merike , Müller Werner E G
Published: March 2010

Recently we established the presence of relatively high amounts of 2′-5′oligoadenylates (2′-5′A) and 2′-5′oligoadenylate synthetase (2′-5′A synthetase) in the marine sponge Geodia cydonium. Here we determined by applying radioimmunoassay and high-performance liquid chromatographical methods that the concentration of 2′-5′A and the activity of 2′-5′A synthetase change following exposure of G. cydonium tissue to environmental stress. The 2′-5′A content and the activity of 2′-5′A synthetase, present in crude sponge extract, increase by up to three-fold after treating sponge cubes for 2 h with natural stressors including heat shock (26°C), cold shock (6°C), pH shock (pH 6), and hypertonic shock and subsequent incubation for 18 h under ambient conditions (16°C). No response was observed after exposure of sponges to an alkaline (pH 10) or hypotonic environment. Similar changes have been found for the expression of heat shock protein HSP70 in G. cydonium. These results show that 2′-5′A in sponges may be useful as a novel biomarker for environmental monitoring.
Responses of carp hepatopancreatic 7-ethoxyresorufin-O-deethylase and glutathione-dependent enzymes to organic pollutants—a field study
Authors: Machala Miroslav , Petřivalský Marek , Nezveda Karel , Ulrich Robert , Dušek Ladislav , Piačka Vladimír , Svobodová Zdenka
Published: March 2010

Modulations of hepatopancreatic activities of cytochrome P4501A (CYP1A) and glutathione-dependent enzymes were investigated in carp collected in five ponds with different levels of contamination. The CYP1A-dependent 7-ethoxyresorufin-O-deethylase activity was markedly induced by polycyclic aromatic hydrocarbons present in the sediment at a total concentration of 0.9 mg/kg. Even a low organic contamination increased some of the glutathione-dependent enzymatic activities, namely cytosolic glutathione reductase, glutathione S-transferase toward 1-chloro-2,4-dinitrobenzene, ethacrynic acid and l,2-epoxy-3-(p-nitrophenoxy)propane, and microsomal glutathione S-transferase. These parameters should be considered as potential tools for the biomonitoring of exposure to chemicals and/or impacts of exposure. An example of a multivariate cluster and discriminant analysis of the obtained analytical and biochemical data proved to be very effectiv tools for the characterization of the level of contamination.
Glutathione-dependent detoxifying enzymes in rainbow trout liver: Search for specific biochemical markers of chemical stress
Authors: Petřivalský Marek , Machala Miroslav , Nezveda Karel , Piačka Vladimír , Svobodová Zdenka , Drábek Petr
Published: March 2010

Activities of trout liver microsomal glutathione S-transferase (GST) and a series of cytosolic glutathione-dependent detoxifying enzymes were determined after a single intraperitoneal treatment with phenobarbital, 2,2-bis (p-chlorophenyl)-1,1-dichloroethane (p,p′-DDE), 2,3,-dimethoxynaphthoquinone (NQ), or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). This study aimed to find xenobiotic-specific parameters applicable as biochemical markers of the impacts of the prototypal xenobiotics. The effects of xenobiotics on cytosolic GST activities were substrate dependent. The rate of conjugation of p-nitrobenzyl chloride was significantly induced by higher doses of p,p′-DDE or NQ. The conjugation of ethacrynic acid was enhanced by phenobarbital, p,p′-DDE, and NQ (i.e., by xenobiotics that do not induce cytochrome P4501A forms). The GST activity against 1,2-epoxy-3-(p-nitrophenoxy)propane was induced only by phenobarbital and by lower doses of p,p′-DDE. The cytosolic GST activity, measured with 1-chloro-2,4-dinitrobenzene as a substrate, was only weakly increased by phenobarbital, TCDD, higher doses of p,p′-DDE, or by NQ at the lowest dose of 1 mg/kg. Although the latter activity is frequently used as a biomarker in ecotoxicology, various factors (including its weak inducibility) indicate that this biochemical parameter is probably not a suitable indicator of contamination in fish. Similarly, cytosolic glutathione peroxidase was not affected by the prototypal xenobiotics and appeared to be an unsuitable bioindicator of oxidative impacts of the tested compounds. On the other hand, microsomal GST activity was nonspecifically increased by phenobarbital, NQ, TCDD, and high doses of p,p′-DDE. Glutathione reductase, another potential biomarker of oxidative stress, was induced by phenobarbital, NQ, and, to a lesser extent, p,p′-DDE; therefore it appeared to be a less sensitive indicator to the exposure to prototypal xenobiotics than the microsomal GST. We conclude that the increase of microsomal GST and cytosolic glutathione reductase activities could become useful biochemical markers of oxidative stress, while the induction of cytosolic GST activities toward ethacrynic acid and probably also toward p-nitrobenzyl chloride appear to hold promise as biochemical markers of specific impacts of p,p′-DDE and redox cycling quinones in trout liver.
Effects of 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), or an extract derived from field-collected cormorant eggs injected into double-crested cormorant (Phalacrocorax auritus) eggs
Authors: Powell Debra C , Aulerich Richard J , Meadows John C , Tillitt Donald E , Powell Jon F , Restum Janelle C , Stromborg Kenneth L , Giesy John P , Bursian Steven J
Published: March 2010

Double-crested cormorant (Phalacrocorax auritus) eggs were injected with either 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), or an extract derived from field-collected double-crested cormorant eggs. These compounds were injected into the yolks of cormorant eggs from an isolated colony on Lake Winnipegosis, Manitoba, Canada. Upon hatching, chicks were necropsied. The brain, bursa, heart, liver, and spleen were removed and weighed. An approximate median lethal dose (LD50) of 158 μg/kg egg was determined for PCB 126, which is 69 times greater than the LD50 determined for the chicken (Gallus domesticus) in a previous study. A significantly greater mortality occurred at the highest dose of TCDD (4.0 μg/kg egg) when compared to the vehicle control. However, the mortality data did not provide sufficient information for the determination of an LD50. The cormorant egg extract did not adversely affect hatchability. No significant increases were observed in the incidence of developmental abnormalities, including pronounced edema, in any of the treatment groups, nor were there any relevant effects on body and organ weights. Based on the results from this study, the cormorant appears to be considerably less sensitive to polyhalogenated diaromatic hydrocarbons than the chicken, which has been the typical species used for egg injection studies.
Using a water-effect ratio approach to establish effects of an effluent-influenced stream on copper toxicity to the fathead minnow
Authors: Diamond Jerome M , Gerardi Christiana , Leppo Erik , Miorelli Thomas
Published: March 2010

Water-effect ratio (WER) testing, examining the relative toxicity of copper in various dilutions of effluent and stream water as compared with laboratory dilution water, was conducted during January, April, and June, 1995, to assess the potential of seasonal and flow effects on site water quality and toxicity of copper to the fathead minnow. Total organic carbon (TOC) and dissolved solids were significantly related to effluent concentration in the site water (R2 = 0.92, p < 0.01), resulting in higher copper median lethal concentrations (LC50s) and higher WERs as effluent contribution in site water increased. Total recoverable copper LC50s were similar to dissolved copper LC50s in laboratory and upstream water tests (p > 0.10), while effluent and stream water tests had significantly higher total recoverable than dissolved copper LC50s (p < 0.01), suggesting more solids or complexing agents when effluent was present. The LC50 and WER for upstream water were significantly higher in April than in January (p < 0.05), consistent with the higher TOC, alkalinity, and lower stream flow observed during April. The WER tests, using different proportions of upstream water and effluent (tests of additivity) in both January and April, indicated that total recoverable copper WER was predictable under a variety of stream flow conditions. Dissolved copper WERs were less predictable, in part because effluent and upstream water WERs were similar, particularly in April. Low-flow stream conditions (when effluent concentration was greatest) appeared to be the limiting condition in terms of greatest copper toxicity at this site. Furthermore, winter low-flow conditions appeared to be more limiting (less water effect on copper toxicity) than similar or even lower flows in spring (April) or summer (June). This was probably due to the higher TOC and dissolved solids present in upstream water in the warmer seasons. All analyses indicated that copper was at least five times less toxic in the effluent-influenced stream water than in typical laboratory test dilution water. Our data indicate that seasonal effects on water quality, as well as stream flow, can be important in determining limiting conditions on copper toxicity in effluent-dominated stream systems.
Chronic effects of organochlorine exposure in sediment to the marine polychaeteNeanthes arenaceodentata
Authors: Murdoch Mary H , Chapman Peter M , Johns D Michael , Paine Michael D
Published: March 2010

Organisms exposed to organochlorinated compounds in sediments are likely to suffer chronic rather than acute effects. Thus, acute toxicity tests are unlikely to truly assess their potential impact. A 120-d toxicity test was designed to assess the impact of organochlorine exposure (polychlorinated biphenyl and dichlorodiphenyltrichloroethane) on the marine polychaete Neanthes arenaceodentata. A two-tiered approach was used: Tier I involved reference sediment spiked with a range of concentrations of the two organochlorines bracketing the concentrations found in natural sediments, and tier II involved field sediments collected from a coastal area contaminated with high concentrations of the same two organochlorines. Testing measured a number of endpoints, including survival, growth, and reproduction. Survival and growth were unaffected in either tier by any of the test sediments. Reproductive endpoints, however, were depressed in both tiers relative to the reference sediment.
Spiking sediment with organochlorines for toxicity testing
Authors: Murdoch Mary H , Chapman Peter M , Norman Don M , Quintino Victor M
Published: March 2010

Sediment toxicity testing integrates responses to sediment variables and hence does not directly indicate cause and effect. One tool for determining cause and effect is sediment spiking, in which relatively uncontaminated sediment is amended with known amounts of contaminants, then tested for toxicity. However, sediment spiking methods vary considerably. The present study details appropriate methodologies (dry and wet spiking) for amending sediments with a range of organic contaminant concentrations, i.e., dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyl (PCB). Target and actual concentrations were similar. A dose response was determined for DDT, but PCB was not toxic in an acute sediment toxicity test. Chronic testing of these same sediments is reported in a companion article in this issue.
Differential toxicity of three polychlorinated biphenyl congeners in developing sea urchin embryos
Authors: Schweitzer Linda E , Hose Jo Ellen , Suffet I H , Bay Steven M
Published: March 2010

The relationship between body burden and toxicity of three individual polychlorinated biphenyl (PCB) congeners in developing sea urchin embryos was investigated to evaluate the validity of current predictive models of PCB toxicity in an invertebrate system. Body burdens of radiolabeled PCB congeners (IUPAC 47, 77, and 153) accumulated from seawater were used to determine median effective concentrations (EC50s) for developmental and cytogenetic effects following a 72-h exposure. Congener 47, a di-ortho-substituted tetrachlorobiphenyl, was found to be at least four times more toxic than congener 77, a non-ortho-substituted (coplanar) tetrachlorobiphenyl, with EC50s of 47 and >218 mmol/kg, respectively, using an embryo development assay. This result contradicts the structure–activity prediction of the mammalian-based toxic equivalents (TEQs) approach, demonstrating the need for an ecotoxicologic model. Congener 153, a di-ortho-substituted hexachlorobiphenyl, was virtually nontoxic in terms of developmental effects at the highest dose (102 mmol/kg) achievable at its limit of water solubility. Cytogenetic analysis was a more sensitive method for assessing toxicity than the embryo development assay. Dose–response relationships were established with mitotic activity being the most sensitive endpoint because the PCBs appeared to inhibit mitosis. At the highest doses, complete mitotic arrest was observed. Congener 77 was found to be at least two times more toxic (EC50 = 30 mmol/kg) than congener 153 (EC50 = 67 mmol/kg) but not as toxic as congener 47 (EC50 < 16 mmol/kg) using mitotic activity as the endpoint for toxicity. Thus, the developmental and cytogenetic endpoints ranked the toxicity of the congeners similarly, but established different EC50s.
High accumulation of tributyltin in blood among the tissues of fish and applicability to environmental monitoring
Authors: Oshima Yuji , Nirmala Kukuh , Go Jyoji , Yokota Yoshiko , Koyama Jiro , Imada Nobuyoshi , Honjo Tsuneo , Kobayashi Kunio
Published: March 2010

High tributyltin concentrations (2.5–52.5 times those in muscle) were detected in the blood of three cultured fish species (Japanese flounder, red sea bream, yellowtail) and wild flatfish. The result suggests that fish serum or plasma can be used for monitoring butyltin contamination in aquatic biota.
Biodegradability of nonaqueous-phase liquids affects the mineralization of phenanthrene in soil because of microbial competition
Authors: Morrison Douglas E , Alexander Martin
Published: March 2010

A study was conducted to determine the effects of biodegradability of nonaqueous-phase liquids (NAPLs) and microbial competition on the biodegradation in soil of a constituent of the NAPLs. The rates of mineralization of phenanthrene dissolved in 8 mg of 2,2,4,4,6,8,8-heptamethylnonane (HMN), di(2-ethylhexyl) phthalate (DEHP), or pristane per g of soil were faster than the rates when the compound was dissolved in hexadecane or dodecane. Addition of inorganic N and P to the soil increased the mineralization rate in the first two but not the last two NAPLs. N and P addition did not enhance mineralization of phenanthrene when added in 500 μg of hexadecane, pristane, or HMN per g of soil. Hexadecane was rapidly degraded, pristane was slowly metabolized, DEHP was still slower, and HMN was not mineralized in the test period. Mixing the soil stimulated mineralization of phenanthrene dissolved in HMN but not in hexadecane. Mineralization of phenanthrene dissolved in HMN was the same if the gas phase contained 21%, 2.1%, or traces of O2. In contrast, the biodegradation of phenanthrene dissolved in hexadecane, although the same at 21 and 2.1% O2, was not observed if traces of O2 were present. The mineralization was slower in unshaken soil–water mixtures if phenanthrene was added in hexadecane than in HMN or pristane, but the rates with the 3 NAPLs were increased by shaking the suspensions. We suggest that the biodegradability of major components of NAPLs and microbial competition for N, P, or O2 will have a major impact on the rate of transformation of minor constituents of NAPLs.
Desorption of chlorinated organic compounds from a contaminated estuarine sediment
Authors: Gess Peter , Pavlostathis Spyros G
Published: March 2010

Batch kinetic and equilibrium partitioning experiments were performed to determine the desorption rate and extent of chlorobenzenes and hexachlorobutadiene found in a contaminated estuarine sediment. A small fraction (less than 3%) of most sediment contaminants desorbed in a single-step batch test performed over 62 d. When a desorption test was conducted with contaminated sediment and successive replenishment of the supernatant, the desorbed contaminant fraction increased to as high as 17% after 33 successive desorption steps were completed. The 1,2,4-trichlorobenzene isomer attained the highest extent of desorption. The desorbed contaminant fraction strongly correlated to the organic carbon-based partition coefficient (Koc) of the contaminants. The two-site model was used to describe the desorption of chlorinated organic compounds from the sediment. Partition coefficients were determined both experimentally and by a computer optimization technique based on the batch desorption kinetic data and the two-site model. The first-order rate constant for the desorption of the contaminants from the “slow” desorption sites ranged from 1.1 × 10−4 to 2.5 × 10−2/d and was negatively correlated with the contaminant hydrophobicity (Koc).
Use of historical PCB Aroclor measurements: Hudson river fish data
Authors: Butcher Jonathan B , Gauthier Thomas D , Garvey Edward A
Published: March 2010

Modern analytical techniques allow the resolution of most individual polychlorinated biphenyl (PCB) congeners; however, analysis of long-term trends in concentration and calibration of environmental fate and transport models often must rely on older, packed-column quantitations against Aroclor standards. These quantitations were often based on a limited set of chromatogram peaks, and methods may have changed over time. It is essential to be wary of false signals in the historical record resulting from changes in analytical schemes. Using an extensive database of historical packed-column quantitations relative to Aroclor standards in Hudson River fish, coupled with recent capillary-column quantitations of PCB congeners, we demonstrate that certain apparent changes in the historical record of PCB Aroclor concentrations are, in fact, partly attributable to changes in quantitation methods. We then offer techniques to “translate” reported Aroclor concentrations to a single, consistent basis. These corrections are essential to a valid interpretation of the historical record of PCB contamination in the Hudson River.
An algal chemostat system for exposure of adsorbable and volatile organic substances
Authors: Halling-Sørensen Bent , Nyholm Niels , Kløft Lene , Kusk Kresten Ole
Published: March 2010

An algal chemostat system for exposure of adsorbable organic substances with potential application also for volatile organic substances has been developed. Volatilization of the test substance has been reduced to a minimum by applying CO,-enriched air (1–2% CO2) introduced at a low flow rate at the bottom of conical reactors. The adsorption of the toxic test compound to tubes was minimized by dosing the medium and the test substance separately. The medium was dosed through of tubes of polyethylene material at a flow rate of 30 ml/h. The test substance was dissolved in a 40%/60% acetone/water mixture and dosed, at a flow rate of 0.125 ml/h, by means of an infusion pump mounted with glass syringes. The chemostat inlet tubes were capillaries of stainless steel. It was possible to maintain a constant dissolved concentration of the test compound in the chemostat, due to a reduction of both volatilization and adsorption. Exposure regimes for phenanthrene, dichlorodiphenyltrichloroethane, and 2,2′,4,4′,5,5′ polychlorinated biphenyl are presented to illustrate the ability of the system to maintain a uniform test substance concentration.
Acute and chronic toxicity of tributyltin and linear alkylbenzene sulfonate to the marine copepodAcartia tonsa
Authors: Kusk K Ole , Petersen Søren
Published: March 2010

The acute toxicities of linear alkylbenzene sulfonate (LAS) and tributyltin (TBT) to the marine copepod Acartia tonsa were tested in 48-h tests at two salinities, 18 and 28‰. For LAS 48-h median lethal concentration (LC50) values were 2.1 and 8.8 mg/L, respectively. For TBT the 48-h LC50 values were 0.47 and 0.24 μg/L, respectively. The given effect concentrations are based on nominal concentrations. In an 8-d test, effects of LAS on larval survival and development effects (effective concentration, 10%) were found at 0.2 to 0.3 mg/L. This effect concentration is higher than environmental concentrations, but at the same level as the concentration that can be expected in effluent from well-operated activated sludge treatment plants. Environmental effects of LAS on sensitive organisms such as A. tonsa would only be expected close to the outlet of effective treatment plants, or if the treatment of the sewage effluent was inefficient. Tributyltin inhibited the developmental rate of larvae at 1 ng TBT/L, whereas the survival of larvae was affected at 15 to 20 ng TBT/L. Acartia tonsa is thus extremely sensitive to TBT. Environmental concentrations of TBT of 20 to 100 ng/L have been found near marinas. Effects on organisms as sensitive as A. tonsa are thus to be expected in the vicinities of marinas. The test method using larval survival and development is easy to perform and nonlaborious compared to, for example, a reproduction test with Daphnia magna. The acute test method as well as the egg–embryo test method may be suitable for standardization.
Distribution of organochlorine contaminants in double-crested cormorant eggs and sibling embryos
Authors: Custer Thomas W , Custer Christine M , Stromborg Kenneth L
Published: March 2010

Double-crested cormorant (Phalacrocorax auritus) fresh eggs and sibling embryos at pipping were collected from a polychlorinated biphenyl (PCB)-contaminated colony in Green Bay, Wisconsin, USA. Egg contents were analyzed for organochlorine (OC) contaminants, including 15 arylhydrocarbon-active PCB congeners. In order to determine the significance of tissue removal on the subsequent estimate of contaminant burden, embryos were decapitated and the heads, yolk sac, liver, fecal sac (allantois), and carcass remainder were analyzed separately. The distribution of contaminant concentration in the embryos was yolk sac > liver > carcass > head > fecal sac. The distribution of contaminant mass in the embryos was yolk sac > carcass > liver > head > fecal sac. For example, mass of total PCBs (TPCB) was yolk sac = 58%, carcass = 31%, liver = 5%, head = 3%, and fecal sac = 1%. Eighteen additional OCs, including 13 PCB congeners, had distribution patterns similar to that of TPCB concentration and mass. Excluding the head of the embryo from the chemical analysis overestimated TPCB concentrations by 15% (16 vs 14 μg/g). In contrast, excluding the liver from the chemical analysis underestimated TPCB concentration by only 4% (13.5 vs 14 μg/g). Mean concentrations of OCs were not significantly different between fresh eggs and sibling embryos.
The influence of food ration on sediment toxicity in Neanthes arenaceodentata (Annelida: Polychaeta)
Authors: Bridges Todd S , Farrar J Daniel , Duke B Maurice
Published: March 2010

A 3 × 2 factorial experiment was conducted to evaluate the influence of food ration on observed toxicity in Neanthes arenaceodentata. Worms were fed one of three food rations: 0.25×, 1.0×, and 6.0×. The 1.0× ration was composed of 4 mg TetraMarin/worm/week and 2 mg alfalfa/worm/week. Worms in each food ration were exposed to one of two sediments: a clean control sediment collected from Sequim Bay, Washington, USA (SC) or a contaminated sediment collected from Black Rock Harbor near Bridgeport, Connecticut, USA (BRH) that was diluted with SC such that the final concentration of contaminated sediment was 12%. Survival and growth were monitored every 2 weeks for 8 weeks. Sediment treatment and food ration had strong effects on survival and growth patterns in N. arenaceodentata. Most of the mortality within any given treatment combination occurred during the first 2 weeks of the experiment. This decline in survival was greatest for worms exposed to BRH. Survival was significantly lower for worms in BRH compared to SC at the 0.25× and 1.0× ration levels. Survival was not reduced for worms in BRH compared to SC at the 6.0× ration level. Worm size during the course of the experiment was positively related to ration level. Significantly reduced size in BRH worms was observed at each monitoring period within the 0.25× and 1.0× rations, but only at weeks 6 and 8 for the 6.0× ration level. The percent difference in size between worms exposed to BRH and SC, when those worms were fed the 0.25× or 1.0× rations, ranged between 55 and 66%. The percent difference in size observed between BRH and SC worms fed the 6.0× ration was much smaller (9–17%). The results of this study demonstrate that food ration has a strong influence on observed toxicity in N. arenaceodentata. The importance of food ration effects on toxicity must be considered while designing chronic sublethal bioassays. To ensure the relevance of bioassay results, the food ration used during a chronic bioassay should produce a pattern of growth in control animals that is similar to patterns of growth observed in nature.
Bioaccumulation factors for chlorinated benzenes, chlorinated butadienes and hexachloroethane
Authors: Burkhard Lawrence P , Sheedy Barbara R , McCauley Dennis J , DeGraeve G Michael
Published: March 2010

A field study was performed that measured bioaccumulation factors (BAFs) for chlorinated benzenes, chlorinated butadienes, and hexachloroethane in four species, Fundulus heteroclitus (mummichog), Callinectes sapidus (blue crabs), Brevoortia patronus (gulf menhaden), and Micropoganias undulatus (Atlantic croaker). The measured BAFs were not significantly different among the fishes. The measured BAFs for the C. sapidus were in good agreement with those measured for the fishes except for hexachloroethane (HCE), E- and Z-11,2,3,4-pentachlorobuta-1,3-diene (E-and Z-PeCBD), and hexachlorobuta-1,3-diene (HCBD). Their measured BAFs were approximately an order of magnitude smaller than those measured for the fishes. The measured BAFs were also in good agreement with BAFs reported/derived from the literature and to BAFs predicted using two methods of the Environmental Protection Agency (EPA) except for HCE, E- and Z-PeCBD, and HCBD in the C. sapidus. These BAFs were much smaller than the reported/derived and predicted BAFs. The smaller BAFs for HCE, E- and Z-PeCBD, and HCBD were consistent with the metabolism abilities for the C. sapidus, and metabolism processes are believed to be the cause for the smaller BAFs. The predicted BAFs were within a factor of five of the measured BAFs for 90% (n = 48) and 94% (n = 32) using the two methods of the EPA.
Toxicity of hexachlorobenzene toHyalella aztecaandChironomus tentansin spiked sediment bioassays
Authors: Barber Timothy R , Fuchsman Phyllis C , Chappie Daniel J , Sferra James C , Newton F Charles , Sheehan Patrick J
Published: March 2010

Fourteen-day, whole-sediment toxicity tests using the amphipod Hyalella azteca and the midge Chironomus tentans were conducted on spiked sediment samples representing a range of hexachlorobenzene (HCB) concentrations. High rates of survival and growth relative to controls were observed in both test species. No observed effects concentrations (NOECs) were equal to the highest HCB concentration tested (42 mg/kg, normalized to 1% total organic carbon). Available literature on the aquatic toxicity of this hydrophobic chemical shows an absence of lethal and sublethal effects from exposure to HCB at or below water solubility concentrations, and toxicity from exposure to dissolved HCB in sediment porewater therefore would not be expected. Because whole-sediment toxicity tests integrate exposure to HCB dissolved in porewater and adsorbed to particles, it was considered possible that exposure via sediment ingestion could cause toxicity; however, no such effect was observed in this study.
The effect of gut contents on dry weight estimates ofChironomus tentanslarvae: Implications for interpreting toxicity in freshwater sediment toxicity tests
Authors: Sibley Paul K , Monson Philip D , Ankley Gerald T
Published: March 2010

Gut contents have long been recognized as a potentially important source of bias in studies concerned with estimating contaminant body burdens in benthic macroinvertebrates. In this study, we show that gut-associated, inorganic material may also lead to significant overestimates of weight in Chironomus tentans larvae in sediment toxicity tests and thus influence statistical interpretation of effects on growth with this organism. Two methods were evaluated regarding their potential to correct for the proportion of larval dry weight contributed by gut contents: purging and determination of ash-free dry weight (afdw). Each method was assessed in a series of 10-d growth tests using (1) clean sand and clay substrates with a restricted particle size distribution (mean particle size: 8, 146, 218, 306, 448, and 592 μm), and (2) sediments collected from both clean and contaminated field sites encompassing a wide range in particle size distribution. Both purging and afdw determination resulted in significant reductions in the dry weight of larvae in most substrates <306 μm and in the field-collected sediments. In these treatments, 7–59% of the dry weight of fourth instar larvae was comprised of inorganic material contained within the digestive tract. Sediment organic carbon was also important; the contribution of gut contents to larval dry weight in a highly organic (23.6%) sediment was only 7.9% despite a small particle size distribution (mean = 149 μm). Correction for ingested material changed the rank order of treatment means in all tests and reduced the number of statistically significant outcomes for many treatment comparisons. Both methods reduced variability (lower standard deviation) associated with mean dry weight estimates, although variability was generally greater with purging than with the afdw method. Based on the results of this study, we recommend that afdw, not dry weight, be used to determine the weight of C. tentans larvae in 10-d and life-cycle tests with this organism.
Acetylcholinesterase inhibition and altered locomotor behavior in the carabid beetlePterostichus cupreus.A linkage between biomarkers at two levels of biological complexity
Authors: Jensen Charlotte S , Garsdal Lone , Baatrup Erik
Published: March 2010

The establishment of cause–effect relationships is fundamental for the interpretation and the predictive value of biomarker responses measured at all levels of biological complexity. In the present study, the biochemical exposure biomarker acetylcholin-esterase (AChE) inhibition was related to locomotor behavior, representing a general effect biomarker at the organismal level. Both sexes of the carabid beetle Pterostichus cupreus were intoxicated with three doses of the organophosphorous insecticide dimethoate. Five elements of their locomotor behavior were measured for 4 h employing computer-aided video tracking, whereupon the whole body AChE activity was measured in the individual beetle. AChE inhibition was strongly correlated with dimethoate dose in both sexes. Alterations in the locomotor behavior were directly correlated with AChE inhibition in male beetles, which responded by reducing the time in locomotion, average velocity, and path length and by increasing the turning rate and frequency of stops. Females responded similarly at the two highest doses, whereas their locomotor behavior was not significantly different from the control group at the lowest dimethoate dose, suggesting a sex-dependent difference in behavioral sensitivity to minor AChE depressions. The results demonstrate that automated measurements of locomotor behavior is at least as sensitive an endpoint to organophosphate poisoning as the AChE assay. Further, the correlation between the molecular and behavioral responses in individual beetles indicates a mechanistic relationship between the two biomarkers.
Effects of simulated solar radiation on the bioaccumulation of polycyclic aromatic hydrocarbons by the duckweed Lemna gibba
Authors: Duxbury Cheryl L , Dixon D George , Greenberg Bruce M
Published: March 2010

Light (particularly ultraviolet B) results in photomodification of polycyclic aromatic hydrocarbons (PAHs) to products with increased polarity and water solubility and enhanced toxicity relative to the parent compounds. The uptake and depuration kinetics of three representative PAHs, anthracene (ANT), phenanthrene (PHE), and benzo [a]pyrene (BAP), and their photomodified products were determined for Lemna gibba. The 14C-labeled PAHs were delivered to the plants in their aqueous growth medium either via a dimethylsulfoxide (DMSO) carrier or adsorbed directly to sand placed in the medium. Assimilation was carried out under simulated solar radiation (SSR) and in darkness. The potential sites of PAH action within the plants were defined by identifying the subcellular location of both intact and photomodified PAHs following assimilation. Lemna gibba had a high capacity for intact ANT, PHE, and BAP in the dark regardless of the two routes of delivery. Depuration was also rapid. Net assimilation of all three PAHs in the dark was always higher when the chemicals were delivered with DMSO than from sand, although first-order kinetics were apparent with both delivery systems. The relative levels of assimilation were PHE > ANT > BAP. Polycyclic aromatic hydrocarbons were rapidly assimilated under SSR, albeit net assimilation for both the intact and photomodified forms was generally lower under SSR compared with darkness. This was also reflected in the bioconcentration factors, which were highest in darkness for each PAH and dropped significantly under SSR and after photomodification. Both intact and photooxidized PAHs accumulated preferentially in the thylakoids and microsomes of L. gibba, suggesting these to be the subcellular compartments most at risk from PAH damage.
Early life-stage mortalities of Japanese medaka (Oryzias latipes) exposed to polychlorinated diphenyl ethers
Authors: Metcalfe Chris D , Metcalfe Tracy L , Cormier James A , Huestis Susan Y , Niimi Art J
Published: March 2010

Polychlorinated diphenyl ethers (PCDEs) are a group of compounds that resemble polychlorinated dibenzofurans in structure that have been detected at ppb concentrations in fish from the Great Lakes. The objective of this project was to determine the toxicological significance of PCDE residues in fish. PCDE congener 77 (3,3′,4,4′-tetrachlorodiphenyl ether), congener 71 (2,3′,4′,6-tetrachlorodiphenyl ether), congener 118 (2,3′,4,4′,5-pentachlorodiphenyl ether), and congener 105 (2,3,3′,4,4′-pentachlorodiphenyl) were tested for toxicity with early life stages (ELS) of Japanese medaka, Oryzias latipes. These embryotoxicity data showed that the mono-ortho congeners 105 and 118 and the non-ortho congener 77 were embryotoxic to medaka. However, the toxic equivalency factors (TEFs) estimated for congeners 105, 77, and 118 relative to 2,3,7, 8-TCDD were relatively low at 0.00056, 0.00003, and 0.00001, respectively. PCDE compounds were isolated in a fraction prepared from a bulk extract of Lake Ontario lake trout. In this fraction, congeners 99 (2,2′,4,4′,5-pentaCDE), 153 (2,2′,4,4′,5,5′-hexaCDE), 154 (2,2′,4,4′,5,6′-hexaCDE), and 163 (2,3,3′,4′,5, 6-hexaCDE) comprised 81.3% of total PCDEs, while congeners 77, 71, 118, and 105 comprised only 1.1% of total PCDEs. The LC50 for embryotoxicity of this fraction was equivalent to 15.5 ng/ml of total PCDEs. Toxicopathic lesions noted in medaka embryos exposed to either individual PCDEs or the lake trout extract included vascular hemorrhage but no edematous lesions. Medaka fry did not exhibit symptoms of hyperexcitability prior to death, as has been noted for ELS of lake trout exhibiting “swim-up syndrome.” These data indicate that PCDEs in Lake Ontario lake trout have the potential to induce toxic effects in early life stages of fish. However, the medaka mortalities were not consistent with observations of either “blue-sac disease” or swim-up syndrome observed in some natural populations of Great Lakes salmonids.
Extrapolation factors for small samples of pesticide toxicity data: Special focus on LD50 values for birds and mammals
Authors: Luttik Robert , Aldenberg Tom
Published: March 2010

For the registration procedure of pesticides it is necessary to have specific information and testing data in order to conduct an ecological hazard/risk assessment. The hazard/risk assessment for acute exposure is usually based on a quotient method, where the estimated environmental concentration is compared with the lowest available 50% lethal dose (LD50) value. Generally there are only one or two LD50s available for birds and mammals, and an underestimation of the potential hazard/risk could be a real possibility. In this article, we propose to estimate a hazardous dose for 5% of the species (HD5) for LD50 data, corresponding with the hazardous concentration for 5% of the species for the no-observed effects concentration (NOEC) data. In addition we describe a method for calculating safety factors that can be used in the case of small sample sizes, especially those smaller than 4 and including n = 1. The safety factors to be applied to the geometric mean of the LD50s for a median estimate of the HD5 of birds and mammals are 5.7 and 3.8, respectively. The safety factors for the 95% confidence limit of the HD5 of birds for n = 1, 2, and 3 are 33, 20, and 16, respectively. For mammals these safety factors are 15, 10, and 8.
Review of the environmental behavior and fate of methyl tert-butyl ether
Authors: Squillace Paul J , Pankow James F , Korte Nic E , Zogorski John S
Published: March 2010

A review of pertinent equations and current research indicates that when gasoline oxygenated with methyl tert-butyl ether (MTBE) comes into contact with water, large amounts of MTBE can dissolve. At 25°C, the water solubility of MTBE is about 5,000 mg/L for a gasoline that is 10% MTBE by weight, whereas for a nonoxygenated gasoline, the total hydrocarbon solubility in water is typically about 120 mg/L. Methyl tert-butyl ether sorbs only weakly to subsurface solids; therefore, sorption does not substantially retard the transport of MTBE by ground water. In addition, MTBE generally resists biodegradation in ground water. The half-life of MTBE in the atmosphere can be as short as 3 d in a regional airshed. In the air, MTBE tends to partition into atmospheric water, including precipitation. However, the washing out of gas-phase MTBE by precipitation will not, by itself, greatly alter the gas-phase concentration of the compound in the air. The partitioning of MTBE to precipitation can nevertheless result in concentrations as high as 3 μg/L or more in urban precipitation and can contribute to the presence of MTBE in surface and ground water.
Variation of the stability of complexes of Al(III) with a fulvic acid extracted from a humic cambisol soil in the pH range three to five
Authors: Esteves da Silva Joaquim C G , Machado Adélio A S C , Ramos M Angeles , Arce Florencio , Rey Francisco
Published: March 2010

The interaction of the aluminum ion [Al(III)] with the major constituent of soil organic matter, fulvic acids (FA), was investigated in the acid pH range. The complexation of a FA extracted from a humic cambisol soil (at a concentration of 80 mg/L) when titrated with Al(III) were monitored directly by synchronous fluorescence (SyF) spectroscopy at five pH values (3.0, 3.5, 4.0, 4.5, and 5.0), at 25°C and with 0.1 N KNO3. Inverted second derivative SyF data were preprocessed by a self-modeling mixture analysis method to obtain fluorescence enhancement profiles as a function of the increasing Al(III) concentration. Assuming that the concentration of complexes formed between Al(III) and FA is proportional to the fluorescence intensity, these profiles were adjusted to a 1:1 complexation model and the following conditional stability constants (log Kc) were calculated (standard deviation in parenthesis), pH = 3.0, 4.3 (1); pH = 3.5, 4.3 (1); pH = 4.0, 5.0 (1); pH = 4.5, 5.1 (3); and pH = 5.0, 5.3 (2). These constants show that the stability of the complexes decreases markedly at pH < 4. The environmental implication of this result is that an increase in the extent of the dissociation of the Al(III) + FA complexes is expected at pH < 4, increasing the free Al(III) concentration and probably its ecotoxicity.