bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of sediments containing atrazine and carbofuran to larvae of the midge Chironomus tentans
Authors: Douglas W. Scott , McIntosh Alan , Clausen John C. 
Published: March 2010

Abstract
Field and laboratory tests were conducted to determine the 10-d toxicity of atrazine and carbofuran to larvae of the midge Chironomus tentans. The pesticides were first spiked onto a clean control sediment, and the midges were exposed to atrazine, carbofuran, or mixtures of both compounds. Laboratory toxicity tests with carbofuran yielded LC50s of 20.5 μg/kg bound to sediment and 11.8 μg/L dissolved in interstitial water. Slight but statistically significant toxicity was detected at the highest tested concentration of atrazine (9,000 μg/kg, bound). Toxic interaction between the two pesticides was assessed using all possible combinations of four concentrations of both pesticides spiked onto clean sediments. Analysis of variance was used to determine if greater than or less than additive effects occurred when both pesticides were present. No toxic interaction between atrazine and carbofuran was detected. Based on laboratory findings, it was predicted that edge-of-field runoff could be toxic to midge larvae if concentrations of carbofuran exceeded 5 μg/kg. To test these predictions, actual edge-of-field runoff was collected from a cornfield receiving atrazine and carbofuran at recommended rates and the suspended sediments used in a toxicity test. Edge-of-field runoff containing carbofuran at 186 μg/kg was acutely toxic to midge larvae.
Cellular biomarkers for measuring toxicity of xenobiotics: Effects of polychlorinated biphenyls on earthworm Lumbricus terrestris coelomocytes
Authors: Goven Arthur J. , Fitzpatrick Lloyd C. , Eyambe George S. , Venables Barney J. , Cooper Edwin L. 
Published: March 2010

Abstract
Acute toxicity in earthworms (Lumbricus terrestris) was assayed immediately after 5-d filter paper exposure to the polychlorinated biphenyl (PCB) Aroclor 1254, using coelomocyte viability, total extruded cell counts (ECC), differential cell counts (DCC), and formation of erythrocyte (ER) and secretory rosettes (SR) with, and phagocytosis of, antigenic rabbit red blood cells (RRBC). Chronic toxicity was assayed using rates by which earthworms replaced viable immunoactive coelomocytes, removed noninvasively immediately after exposure, over an 18-week depuration period. All cytological parameters, except ECC, were acutely affected immediately after exposure, when tissue concentrations were (X ± se) 91.2 ± 8.19 μg PCB per gram dry mass. Replacement of viable immunoactive coelomocytes occurred within six weeks in unexposed control earthworms. Exposed earthworms showed significant alteration in viability, ECC, DCC, ER, and SR formation, and phagocytosis at 6 and 12 weeks when PCB tissue concentrations were 41 ± 0.31 and 30.2 ± 0.88 μg/g dry mass, respectively. Replacement of extruded coelomocytes with normal DCC of viable immunocompetent cells was not observed until week 18, when PCB had decreased to 15.7 ± 0.83 μg/g dry mass. Low inherent natural variability in coelomocyte viability, ECC, DCC, rosette formation, and phagocytosis, and their sensitivity to sublethal PCB body burdens, indicated that earthworm coelomocytes have potential as nonmammalian biomarkers for assaying acute and chronic sublethal toxicity of xenobiotics.
Caged and wild fish: Induction of hepatic cytochrome P-450 (CYP1A1) as an environmental biomonitor
Authors: Haasch Mary L. , Lech John J. , Prince Ruth , Cooper Keith R. , Wejksnora Peter J. 
Published: March 2010

AbstractHepatic monooxygenase activity can be induced by many different environmental chemical contaminants, and measurement of this activity has been proposed as an environmental biomonitor. Using in situ caged catfish and largemouth bass, and collected wild killifish, environmental induction of hepatic CYP1A1 was investigated using catalytic enzyme assays, regiospecific metabolism, immunodetection, and nucleic acid hybridization. The purpose of these studies was to evaluate these techniques for detection of CYP1A1 induction as a potential environmental biomonitor of environmental chemical contamination. Exposure of catfish in cages to polyaromatic hydrocarbon- (PAH-) and polychlorinated biphenyl- (PCB-) contaminated river water for two, four, or six weeks resulted in fourfold increases in ethoxyresorufin-O-deethylase (EROD) activity and three- and fivefold increases in immunoreactive CYP1A1 protein and hybridizable CYP1A1 mRNA, respectively, when compared to laboratory water control values. Hybridizable CYP1A1 mRNA in caged largemouth bass increased 5.1-fold at 1 d of exposure. Caged largemouth bass had 5-, 1.4-, and 0.8-fold increases at 3 d and 6-, 2.4-, 0.4-fold increases at 7 d of river water exposure in EROD, immunoreactive CYP1A1 protein, and CYP1A1 mRNA, respectively, when compared to laboratory water control values. Livers of killifish from a 2,3,7,8-tetrachlorodibenzo-p-dioxin-contaminated area had threefold higher EROD activity and similarly elevated immunoreactive CYP1A1 protein, a two- to fourfold increase in CYP1A1 mRNA, and a four- to eightfold increase in 6β-hydroxyprogesterone activity, when compared to killifish livers sampled from a “clean” site. These results indicate that catalytic activity measurements, immunodetection, and nucleic acid hybridization may be used to detect environmental hepatic CYP1A1 induction in fish, and may be useful for the biomonitoring or screening of selected environments for chemical contamination.
Benzo[a]pyrene metabolism and excretion in white suckers with chronic liver diseases
Authors: Smith Ian R. , Kirby Gordon M. , Ferguson Hugh W. , Hayes M. Anthony 
Published: March 2010

Abstract
Wild white suckers (Catostomus commersoni) with diseased bile ducts excreted an oral dose of benzo[a]pyrene (BaP) into their bile as glucuronide, glutathione, and sulfo-conjugates at twice the rate (16.76 nmol/h) of an unaffected reference population (7.52 nmol/h). BaP-hydroxylase (10% higher in the diseased population), glutathione-S-transferase (similar), or uridine-5′-diphos-phoglucuronic acid transferase (50% lower) levels did not correlate with these excretion rates. Metabolite levels were 57% higher in the liver of affected suckers than those in the liver of reference suckers, which might be due to bile retention within the diseased bile ducts. The bile duct disease affecting white suckers does not appear to restrict the metabolism and excretion of BaP.
Synthesis and accumulation of stress proteins in tissues of arsenite-exposed fathead minnows (Pimephales promelas)
Authors: Dyer Scott D. , Brooks G. Lance , Dickson Kenneth L. , Zimmerman Earl G. , Sanders Brenda M. 
Published: March 2010

AbstractThe stress protein response (SPR) is a ubiquitous, protective, and defensive mechanism that enables cells to tolerate environmental perturbations. Induction of the SPR involves the increased transcription of stress protein genes, the products of which function in protein folding, multimeric protein assembly, receptor interactions, and heme catabolism, and so forth. The potential of this response as an indicator of water quality was evaluated in gill and striated muscle tissues of fathead minnows (Pimephales promelas) exposed to a wide range of concentrations of sodium arsenite for various lengths of time.The SPR in gill was elicited rapidly, occurring by 2 h exposure at 25 mg/L. The response was tissue specific. In gill, synthesis and accumulation rates of 20-, 40-, 70-, 72-, and 74-kD proteins were significantly increased, compared to controls. In muscle, 20-, 30-, 68-, 70-, and 90-kD proteins also showed significantly increased syntheses and accumulations. Synthesis and accumulation rates of arsenite-induced proteins 20-, 70-, 72-, and 74-kD in gill were significantly correlated with mortality. However, in striated muscle, only the 70-kD was significantly correlated with mortality.
An evaluation of the toxicity of various forms of chlorine to Ceriodaphnia dubia
Authors: Taylor P.A. 
Published: March 2010

Abstract
Ambient toxicity tests at 15 sites on five small streams that receive discharges from Oak Ridge National Laboratory (TN) showed that chlorine (mostly from once-through cooling water) was an important toxicant; however, there was not a good correlation between chlorine concentration and toxicity to Ceriodaphnia dubia in the ambient tests. To better understand the toxicity of chlorine, its various forms (hypochlorite ion, hypochlorous acid, monochloramine, and dichloramine) were tested individually. Standard Ceriodaphnia dubia acute toxicity tests (static, 24 h, with added food) showed that the chloramines were very toxic (LC50 &lt; 0.02 mg/L) but that free chlorine (hypochlorous acid and hypochlorite ion) was much less toxic (LC50s of 0.14 and 0.08 mg/L, respectively). Chlorine decay measurements in the toxicity test solutions showed that free chlorine reacts very rapidly (&lt;1 min) with the Ceriodaphnia dubia food (a mixture of digested trout chow, yeast, and Cerophylř) added to the solutions, so the standard toxicity test measured the toxicity of chlorinated food rather than the toxicity of free chlorine. Static tests without food showed LC50s of 0.012 mg/L for monochloramine, 0.016 mg/L for dichloramine, 0.035 mg/L for hypochlorous acid, and 0.048 mg/L for hypochlorite ion; however, the free chlorine still decayed rapidly (&lt; 7 h) in the test solution. Continuous-flow toxicity tests showed that free chlorine is more toxic than the chloramines, with LC50s of 0.005 mg/L for hypochlorous acid, 0.006 mg/L for hypochlorite ion, 0.016 for monochloramine, and 0.027 mg/L for dichloramine. The LC50s for hypochlorous acid and hypochlorite ion are substantially below the U.S. Environmental Protection Agency's 4-d average water-quality criterion for chlorine of 0.011 mg/L
Sublethal narcosis and population persistence: A modeling study on growth effects
Authors: Hallam Thomas G. , Canziani Graciela Ana , Lassiter Ray R. 
Published: March 2010

Abstract
This study of a Daphnia population model suggests that sublethal effects of nonpolar narcotics on growth of individual organisms can result in ultimate extinction of the population at chronic chemical concentrations near the effect concentration that leads to a 50% reduction in individual growth (the 16-d EC50 for growth). A quantitative dose-response relationship (QDRR)—a population extinction threshold, relating the minimal chronic chemical concentration that yields population persistence and the octanol/water partition coefficient (Kow)—is generated from numerical simulation studies of a Daphnia population model. The transition from population persistence to extinction is examined in terms of density functions in the lipid, structure, and age variables associated with models of individual daphnids. The densities of populations undergoing transition from persistence to extinction due to increased toxicity suggest that critically stressed populations are age-bimodal with a component of old, large individuals and a component of small, nonreproductive individuals. The populations that persist near the threshold for extinction are unexpectedly diverse in age density and consist of relatively small individuals.
Induction of cytochrome P450 1A in fish treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin or chemically contaminated sediment
Authors: van der Weiden Martine E.J. , Seinen Willem , van Den Berg Martin , Celander Malin , Föurlin Lars , Goksøsyr Anders 
Published: March 2010

Abstract
Mirror carp were exposed to Rotterdam Harbor sediment, highly contaminated with polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and polychlorobiphenyls (PCBs) (0.5 μg 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] equivalents per kilogram dry weight). In two additional separate experiments rainbow trout (Oncorhynchus mykiss) and mirror carp (Cyprinus carpio) received a single intraperitoneal injection of approximately 0.01, 0.03, 0.06, 0.3, 0.6, or 3.0 μg TCDD per kilogram body weight. In all three experiments induction of hepatic P450 1A was measured with immunochemical and enzymatic methods. The polyclonal antibodies anticod (Gadus morhua), anti-perch (Perca fluviatilis), and anti-rainbow trout P450 1A all cross-reacted with the P450 1A orthologue of the carp and rainbow trout. In most cases high correlations were found between 7-ethoxyresorufin O-deethylation (EROD) activity and cytochrome P450 1A protein contents, the latter measured by the enzyme-linked immunosorbent assay (ELISA) and protein blot methods. However, the correlations between EROD activity and P450 1A protein levels were higher within the separate sampling periods (i.e., 3, 6, and 12 weeks after dosage) than with the total data set, especially in the dose-effect study with the rainbow trout. This was probably caused by a difference in time-dependent relationships between P450 1A protein content and EROD enzyme activity: 12 weeks after dosage the P450 1A protein was still increased, although EROD activity had returned to background level. In addition, there were higher correlations of the EROD activity and P450 1A protein content with total P450 content in rainbow trout and carp treated with a single dose of TCDD, than with total P450 content in carp exposed to contaminated sediment. In our study, the ELISA method appeared to be more useful than the protein blot technique, because the ELISA is faster and has higher reproducibility. In addition, in all our experiments EROD activity showed a higher induction than the P450 1A protein, indicating a higher sensitivity of the EROD assay. Our results strongly indicated that determination of the P450 1A protein content and EROD activity provides complementary information. Thus we recommended the use of both the ELISA and the EROD activity assay in order to understand the nature of P450 1A induction.
Reductive dechlorination of aroclor 1242 in anaerobic sediments: Pattern, rate and concentration dependence
Authors: Rhee G.-Yull , Bush B. , Sokol R.C. , Bethoney C.M. , DeNucci A. , Oh H.-M. 
Published: March 2010

Abstract
Anaerobic biotransformation of polychlorinated biphenyls of Hudson River sediment microorganisms was investigated using the commercial mixture Aroclor 1242 in the laboratory at six different concentrations: 120, 300, 500, 800, 1,000, and 1,500 μg/g (on a sediment dry-weight basis). Dechlorination was concentration dependent. No change in congener composition was found at 1,000 and 1,500 μg/g during seven months of incubation, but significant shifts were observed in sediments with concentrations below 800 μg/g. A mass balance of the transformation indicated that, despite the shifts, the total molar concentration remained the same. An optimum concentration, based on the decrease of Cl per biphenyl, was 500 μg/g, but based on Cl removed per gram sediment it had a range from 500 to 800 μg/g. Dechlorination (total Cl removed per biphenyl) at 300 and 500 μg/g appeared to be first order, with rate constants of —0.039 and —0.059 per month, respectively. The rate also varied with the substitution position; it was faster for m-Cl, followed by p-Cl, but no o-Cl was removed. However, the faster rate of m-dechlorination in Aroclor 1242 was probably due to a high concentration of congeners in the Aroclor with Cl substitution patterns favoring its removal, rather than the meta-position itself.
Toxicokinetics of halogenated benzenes in fish: Lethal body burden as a toxicological end point
Authors: Sum Dick T.H.M. , Schipper Maria , Opperhuizen Antoon 
Published: March 2010

AbstractThe lethal body burden (LBB), the whole-body concentration in millimoles per kilogram at time of death or immobilization, and the LC50 of dihalogenated (F, Cl, Br) benzenes were measured. Except for 1,4-difluorobenzene in guppy (28 mmol kg−1), LBBs varied between 2 and 8 mmol kg−1. The LBBs of the chemicals in guppies were not significantly different from those in fathead minnows. LC50 values varied between 0.54 and 41 μmol L−1 and were inversely related to the octanol/water partition coefficient, Kow. To estimate the risk of a compound to fish, the LBB requires the exposure concentration in combination with a first-order one-compartment bioaccumulation model. Therefore, the time of death or the time of immobility, and bioconcentration parameters such as the uptake rate constant (k1) and the elimination rate constant (k2), were determined. For both species, k1 values of the chlorinated benzenes were smaller than those of the brominated compounds and k2 values decreased with increasing hydrophobicity. The lipid-normalized bioaccumulation factors (KL's) were linearly related to Kow.
Regression analysis of log-transformed data: Statistical bias and its correction
Authors: Newman Michael C. 
Published: March 2010

AbstractPower and exponential models are used frequently in environmental chemistry and toxicology. Such models can generate biased predictions if derived with least-squares, linear regression of log-transformed variables. An easily calculated but seldom used estimate of bias can enhance the accuracy of subsequent predictions. This prediction bias and means of correcting it are presented, along with several examples.
Chlorinated and brominated persistent organic compounds in biological samples from the environment
Authors: Jansson Bo , Andersson Renate , Asplund Lillemor , Litzen Kerstin , Nylund Kerstin , Sellströom Ulla , Uvemo Ulla-Britt , Wahlberg Cajsa , Wideqvist Ulla , Odsjö Tjelvar , Olsson Mats 
Published: March 2010

Abstract
Eleven selected biological samples representing different ecosystems, trophic levels, and areas mainly in Sweden have been analyzed for 31 halogenated organic compounds or compound groups. The multiresidue analytical method provides a good opportunity to compare the concentrations of the different compounds in the investigated samples. By the use of ratios of these concentrations, comparisons can be done between species and areas. An attempt to describe an environmental distribution profile is demonstrated for some of the compounds using the concentration ratio between these compounds and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153). Chlorinated paraffins (CPs) were found in all samples (130-4,400 ng/g lipid weight [lw]) and in some of them at higher concentrations than the polychlorinated biphenyls (PCBs). The ratio of CP to PCB 153 is higher in the investigated terrestrial species than in the aquatic, which is not the case for the other compounds. Polybrominated diphenyl ethers (PBDEs) were also found in all but one sample (&lt; 3-2,140 ng/g lw). The concentrations were highest in industrialized areas but were also present in samples from background areas. Seven major congeners of PCBs were determined; the sum ranged from 50 to 200,000 ng/g lw in the investigated samples. Three coplanar PCB congeners were also analyzed (0.42-160 ng/g lw) as well as polychlorinated naphthalenes (PCNs), which were found at levels between 0.038 and 50 ng/g lw. The latter two groups do not seem to biomagnify in the food chain of herring to grey seal to the same extent as the major PCB compounds. Pentachlorobenzene was found in only three of the samples (0.6-35 ng/g lw), whereas hexachlorobenzene was present in all samples (9-330 ng/g lw). Among the organochlorine pesticides, total DDTs ranged from 4 to 280,000 ng/g lw and the hexachlorocyclohexanes (HCHs) from &lt; 19 to 650. Chlordane (&lt; 6-4,000 ng/g lw), toxaphene (not detected-5,700), and dieldrin (&lt; 11-340) were also found. None of the analyzed polychlorinated phenols and guaiacols were detected in any of the investigated samples.
Distributions of butyltins in the surface sediment of Ise Bay, Japan
Authors: Yonezawa Yoshitaka , Nakata Kisaburo , Miyakozawa Yoshikazu , Ochi Akiko , Kowata Takao , Fukawa Hiroaki , Sato Yuuji , Masunaga Shigeki , Urushigawa Yoshikuni 
Published: March 2010

Abstract
Concentrations of tri-n-, di-n-, and mono-n-butyltin (TBT, DBT, and MBT) were determined for surface sediments collected from 44 sites within Ise Bay, Japan. The concentrations of TBT, DBT, and MBT ranged from not detected (ND) to 0.11, ND to 0.073, and ND to 0.098 μg g−1 dry sediment, respectively, excluding one site near a shipyard (TBT concentration 0.54-1.1 μg g−1 dry sediment). The distribution patterns of the three butyltins were similar to each other. The concentration of TBT correlated to the organic carbon (OC) content of the sediment and did not correlate to the sediment particle size. The area with high concentration of butyltin extended from the eastern side of the middle of the bay toward the southwest to Tsu-Matsuzaka Port. This area had a high organic content area and corresponded to the downwelling zone simulated by a baroclinic three-dimensional hydrodynamic model. Another area with high butyltin concentrations, near Yokkaichi Port, was also located in the simulated downwelling zone. The area near Nagoya Port, which is in the simulated upwelling zone, had low butyltin concentrations, although the amount of TBT loading in Nagoya Port was estimated to be several times greater than that in Yokkaichi Port. The ratio of TBT to MBT decreased along the direction of surface flow from Yokkaichi Port to the middle of the bay. These results suggested that the amount of the TBT loading could not explain all of the distribution of the TBT concentration in the sediment, and that tidal bay circulations, hydrodynamically up- and downwelling, and surface flow affected it strongly.
A Mercury saturation assay for measuring metallothionein in fish
Authors: Dutton Michael D. , Stephenson Malcolm , Klaverkamp Jack F. 
Published: March 2010

Abstract
An accurate, rapid, sensitive, and simple method using mercury saturation for quantifying metallothionein (MT) is described. A complex solution (“pseudocytosol”) of enzymatic and non-enzymatic thiols, including rabbit liver MT-II, and supernatants from homogenized samples of rainbow trout liver were incubated in the presence of 203Hg in 10% trichloroacetic acid Excess Hg was bound to and removed by chicken egg albumin, which denatured on contact with the acidic assay medium. After centrifugation, MT labeled with 203Hg remained in the TCA supernatant and was estimated using known stoichiometry for Hg-MT binding. A dilution series was used to establish that nonspecific metal binding, a common problem with other metal saturation assays, is negligible. Analysis of hepatic MT with high Cu content from rainbow trout demonstrated virtually complete displacement of Cu, Cd, and Zn by Hg. When compared to other metal-saturation assays developed for vertebrates, this method requires the least number of technical steps, and one-third or less of total preparatory and analytical time.
Studies on the effects of the insecticides phorate and malathion on soil microorganisms
Authors: Gonzalez-Lopez J. , Martinez-Toledo M. V. , Rodelas B. , Salmeron V. 
Published: March 2010

Abstract
A study was made of the effects of two selected organophosphorus insecticides, phorate and malathion, at concentrations of 10, 50, 100, 200, and 300 μg/g of an agricultural soil on total bacteria populations, fungi, aerobic dinitrogen-fixing bacteria, denitrifying bacteria, nitrifying bacteria, and nitrogenase activity (acetylene-reduction assay). The presence of phorate at a concentration of 300 μg/g or malathion at concentrations of 100 to 300 μg/g significantly decreased dinitrogen fixation. Dinitrogen-fixing bacteria significantly decreased at concentrations of 100 to 300 μg/g of malathion. The presence of 10 to 300 μg/g of malathion significantly reduced the total number of bacteria. However, denitrifying bacteria were significantly increased at concentrations of 50 to 300 μg/g of malathion. Nitrifying bacteria and fungal populations were not affected as a consequence of the addition of the organophosphorus insecticides, showing that these microorganisms can tolerate high amounts of those substances.