bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of chroma in pulping effluent by ratio spectrum‐derivative spectrophotometry
Authors: Chen Honglei , Chen Yuancai , Zhan Huaiyu , Fu Shiyu
Published: February 2010

A new method is proposed for the determination of chroma in pulping effluent, using ratio spectrum‐derivative spectrophotometry. The ratio derivative value at 366 nm was used to calculate chroma, which is not affected by pH value and suspended substance in pulping effluent, so the procedure does not require adjusting the pH value and removing the suspended substance before the detection of chroma. The test procedures were simplified and the error caused by human factors was reduced. The method has high precision and accuracy with a relative difference is within ±5% when the chroma of samples is in the range of 50–390 color unit. The new method was satisfactorily applied for the determination of chroma in pulping effluent. © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Efficiency of permeable pavement systems for the removal of urban runoff pollutants under varying environmental conditions
Authors: Tota‐Maharaj Kiran , Scholz Miklas
Published: February 2010

Urban surface water runoff typically contains a high but variable number of pathogens, nutrients, and sediments that require removal before reuse. Permeable pavements can improve the water quality through interception, filtration, sedimentation, nutrient transformation, and microbial removal. There is currently insufficient scientific information available on the treatment efficiencies of permeable pavements combined with earth energy systems with regards to the removal of storm water pollutants such as nutrients, sediments, and microbial pollutants. This study evaluates the efficiency of 12 tanked combined systems during a medium‐term study. The research assessed weekly the removal of the microbial indicators total coliforms, Escherichia coli, and fecal Streptococci, as well as the key nutrients ammonia‐nitrogen, nitrate‐nitrogen, and ortho‐phosphate‐phosphorus, and physical variables such as suspended solids and turbidity. Total coliforms, E. coli, and fecal Streptococci were removed by 98–99%. The ammonia‐nitrogen and ortho‐phosphate‐phosphorus removal efficiencies were 84.6% and 77.5%, respectively. An analysis of variance indicated that the presence or absence of a geotextile did result in a very highly statistically significant difference (P < 0.001) with respect to the removal of both ammonia‐nitrogen and ortho‐phosphate‐phosphorus. Suspended solids, turbidity, and biochemical oxygen demand were reduced by 91%, 82%, and 88%, respectively. These results indicate the potential of the proposed novel system in urban runoff pollutant removal and subsequent reuse of the treated water. © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Bacteriological elimination in sewage sludge through direct flow convective drying
Authors: Serenotti Fernando , Vieira Melissa G.A. , da Silva Meuris G.C. , Pisani Beatriz , Simões Marise , Prandi Maria Ângela Garnica
Published: February 2010

Sewage sludge, one of the main components of the wastewater generated worldwide, is a residue with high moisture content. Because thermal drying allows volume reduction and microbiological inactivation, its use can be considered a powerful tool in the environmental area.

The purpose of this study was to assess the drying process conducted with an upflow direct convection dryer for bacteriological disinfection by verifying the microorganisms E. coli and Salmonella spp, prior to and following the drying process. The study suggested that the most favorable drying condition occurred at the temperature of 140°C and flow of 0.4 kg/min, while all the conditions applied to disinfection were also efficient, since the sludge was exposed to a temperature equal to or above 60°C for more than 1 h in all the conditions, which exceeds the exposure time recommended for the death of the bacteria aforementioned. © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Biosorption of lead and cadmium ions from aqueous solutions onto natural dye waste of Hibiscus rosa sinensis
Authors: Vankar Padma S. , Sarswat Rishabh , Malik Devendra S.
Published: February 2010

The adsorption of Cd2+ and Pb2+ onto natural dye waste (aqueous color extracted) of Hibiscus rosa sinensis flower has been studied in this work. Batch adsorption studies were carried out to examine the effects of process parameters such as pH, temperature, agitating rate, adsorbent mass, and particle size on metal uptake by Hibiscus dye waste (HDW) for Cd2+ and Pb2+. The sorption process was fast and equilibrium was achieved in about 150 min of contact. The extent of adsorption of lead and cadmium increased with an increase of pH as well as adsorbent doses, while decreased adsorbent particle size. The adsorption data followed the Langmuir model better than the Freundlich model. Adsorption equilibrium was described well by the Langmuir isotherm model with adsorption maxima at equilibrium to be 90.909 mg/g of lead ions, and 103.093 mg/g of cadmium ions on HDW sorbent at 20°C. The reversibility of the process was investigated and desorption was observed only in acidic pH values, and was generally high. This study indicated that the HDW can be used as an effective and environmentally safe biosorbent for the treatment of lead containing aqueous solutions. Thus, HDW sorbent is promising substrate to be suitable for electroplating waste water treatment (containing high amounts of lead and cadmium). © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Risk assessment by analysis of extrapolation error: A demonstration for effects of pollutants on fish
Authors: Suter G. W. , Vaughan D. S. , Gardner R. H.
Published: February 2010

This article describes a new method for risk assessment and applies it to assessing the risk of chronic toxicity of mercury to largemouth bass. The method consists of extrapolation between taxa and between toxicity test types by regression analysis. The variance terms in the regression analyses are combined with the point estimate of the geometric mean of the maximum allowable toxic concentration (GMATC) to derive a probability distribution of the GMATC. This distribution is then compared to the ambient contaminant concentration to derive the probability or risk of chronic toxicity. This general approach to risk analysis is applicable to any organism or toxicant.
Differential survival of fathead minnows,Pimephales promelas, as affected by copper exposure, prior population stress, and allozyme genotypes
Authors: Schlueter Mark A , Guttman Sheldon I , Oris James T , Bailer A John
Published: February 2010

Two populations of fathead minnows (F1, offspring of survivors of an acute fluoranthene exposure; N1, naive hatchery fish born in outdoor ponds) were concurrently exposed to approximately 850 μg/L of copper for 132 h. During the exposure, 49% of the F1 and 85% of the N1 minnows died. A curled operculum deformity, detected in 54% of the F1 population, was significantly related to mortality. A failure time regression model, combining both the F1 and N1 populations together, was fit to examine the relationship between population type (F1 or N1), body condition (weight/length3), presence of an operculum deformity, and different allozymes on time to death (TTD). The model indicated that type of population, body condition, the presence of an operculum deformity, and three loci (GPI-1*, IDHP-1*, and MDH-2*) were significantly related to TTD. The F1 minnows had a higher survival rate and longer average TTD compared to N1 minnows. In comparison to the N1 population, the F1 population possessed a higher frequency of genotypes associated with increased survivorship at the IDHP-1* and MDH-2* loci. Weight (and body condition) was negatively correlated with survivorship. Minnows with a severe operculum deformity, believed to be a result of parental exposure to fluoranthene, had a 100% mortality rate and exhibited a considerably reduced TTD compared to nondeformed minnows. Multilocus heterozygosity was not related to TTD for either population. This study indicates that genetic factors may exhibit stronger effects on survivorship than other factors (e.g., weight/body condition) commonly associated with fitness.
Predicting modes of toxic action from chemical structure: Acute toxicity in the fathead minnow (Pimephales promelas)
Authors: Russom Christine L , Bradbury Steven P , Broderius Steven J , Hammermeister Dean E , Drummond Robert A
Published: February 2010

In the field of aquatic toxicology, quantitative structure-activity relationships (QSARs) have developed as scientifically credible models for predicting the toxicity of chemicals when little or no empirical data are available. In recent years, there has been an evolution of QSAR development and application from that of a chemical-class perspective to one that is more consistent with assumptions regarding modes of toxic action. The objective of this research was to develop procedures that relate modes of acute toxic action in the fathead minnow (Pimephales promelas) to chemical structures and properties. An empirically derived database for diverse chemical structures of acute toxicity and corresponding modes of toxic action was developed through joint toxic action studies, the establishment of toxicodynamic profiles, and behavioral and dose-response interpretation of 96-h LC50 tests. Using the results from these efforts, as well as principles in the toxicological literature, approximately 600 chemicals were classified as narcotics (three distinct groups), oxidative phosphorylation uncouplers, respiratory inhibitors, electrophiles/proelectrophiles, acetylcholinesterase inhibitors, or central nervous system seizure agents. Using this data set, a computer-based expert system has been established whereby chemical structures are associated with likely modes of toxic action and, when available, corresponding QSARs.
Aryl hydrocarbon receptor-mediated toxic potency of dissolved lipophilic organic contaminants collected from Lincoln Creek, Milwaukee, Wisconsin, USA, to PLHC-1 (Poeciliopsis lucida) fish hepatoma cells
Authors: Villeneuve Daniel L , Crunkilton Ronald L , DeVita William M
Published: February 2010

Lincoln Creek is a severely degraded urban stream located in Milwaukee County, Wisconsin, USA. As part of a comprehensive study on effects of urban storm water runoff on the stream biota, an in vitro bioassay with PLHC-1 (Poeciliopsis lucida) fish hepatoma cells was used to assess potential toxic potency of aryl hydrocarbon receptor (AhR)-active compounds, collected by semipermeable membrane devices (SPMDs) exposed to Lincoln Creek water. Dialysates from SPMDs exposed to Lincoln Creek water caused marked cytochrome P4501A induction in PLHC-1. Toxic potency of dialysates, expressed as bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ) ranged from 1,300 to 6,600 pg TCDD-EQ/g SPMD for 14-d exposures. Dialysates from SPMDs exposed to stream water at base flow had potencies consistently lower than those exposed to storm-flow (high-flow) events that occurred during the same 14-d period. Polychlorinated biphenyls were not detectable in the dialysates. Gas chromatography-mass spectrometry analysis identified polycyclic aromatic hydrocarbons (PAHs) as major contaminants in the dialysates. A log-log correlation of total PAHs and TCDD-EQ yielded an r2 of 0.802. Empirical evidence suggests that AhR-active PAHs can account for about 20 to 50% of the potency observed.
The toxicity of malathion to unionid mussels: Relationship to expected environmental concentrations
Authors: Keller Anne E , Ruessler D Shane
Published: February 2010

The acute toxicity of malathion to glochidia, juvenile, and adult freshwater mussels was determined at pH 7.5 in soft water and at pH 7.9 in moderately hard reconstituted fresh water at 25°C and 32°C. Nine species were tested in one or more life stages. Glochidia tests were conducted for 4, 24, or 48 h, while juvenile and adult exposures lasted 96 h. Overall, Utterbackia imbecillis was the least sensitive species for all exposure conditions and life stages. The LC50 values for glochidia tested at 25°C ranged from 7 mg/L for Lampsilis siliquoidea (4 h) to 324 mg/L for U. imbecillis (48 h). At 32°C, glochidia LC50s were 119 mg/L for Villosa lienosa (48 h) and 374 mg/L for U. imbecillis (24 h). Tests with juvenile mussels produced 96-h LC50s ranging from 24 mg/L for Lampsilis straminea claibornensis at 25°C to 219 mg/L for U. imbecillis at 25°C. The 96-h LC50s for three species of adult mussels were greater than the highest malathion exposure concentration of 350 mg/L. These values are considerably higher than the reported 48-h LC50 of 1 μg/L for Daphnia magna and the 96-h LC50 of 0.76 μg/L for Gamarus fasciatus but are similar to 96-h LC50s for some fish. Expected environmental concentrations should not be lethal to unionids.
Levels of asymmetry in Formica pratensis Retz. (Hymenoptera, insecta) from a chronic metal-contaminated site
Authors: Rabitsch Wolfgang Bernhard
Published: February 2010

Asymmetries of bilaterally symmetrical morphological traits in workers of the ant Formica pratensis Retzius were compared at sites with different levels of metal contamination and between mature and pre-mature colonies. Statistical analyses of the right-minus-left differences revealed that their distributions fit assumptions of fluctuating asymmetry (FA). No direct asymmetry or antisymmetry were present. Mean measurement error accounts for a third of the variation, but the maximum measurement error was 65%. Although significant differences of FA in ants were observed, the inconsistent results render uncovering a clear pattern difficult. Lead, cadmium, and zinc concentrations in the ants decreased with the distance from the contamination source, but no relation was found between FA and the heavy metal levels. Ants from the premature colonies were more asymmetrical than those from mature colonies but accumulated less metals. The use of asymmetry measures in ecotoxicology and biomonitoring is criticized, but should remain widely applicable if statistical assumptions are complemented by genetic and historical data.
The effects of a C12–13 linear alcohol ethoxylate surfactant on periphyton, macrophytes, invertebrates and fish in stream mesocosms
Authors: Dorn Philip B , Rodgers John H , Gillespie William B , Lizotte Richard E , Dunn Arthur W
Published: February 2010

The ecological effects of a C12–13 linear alcohol ethoxylate (LAE) were studied in stream mesocosms. The surfactant has an average distribution of six and one-half ethylene oxide groups per mole of alcohol. Responses of periphyton, macrophytes, invertebrates, and fish were examined and used to estimate a mesocosm-predicted no-observable-effect concentration (NOEC). The stream mesocosm experiment consisted of a 2-week period of natural colonization, a 30-d treatment period, and a 2-week post-treatment period. Four surfactant concentrations in duplicate streams were used along with two untreated control streams. Surfactant concentrations were delivered to the streams with no apparent loss during the 17-min transit time. The structural integrity of the surfactant was also maintained with no observed differences between the head, middle, or tail sections of individual streams. Average measured concentrations of LAE for replicate streams were 0.32, 0.88, 1.99, and 5.15 mg/L. Periphyton and Myriophyllum aquaticum did not show significant effects. The no-observed-effect concentration (NOEC) for all periphyton and M. aquaticum parameters was 5.15 mg/L, the highest concentration tested. Statistically significant effects were observed on Simuliidae, Copepoda, and Cladocera densities during the treatment period in all exposure concentrations. Thus, the lowest-observed-effect concentration (LOEC) for invertebrate densities was 0.32 mg/L. Drifting invertebrates did not show significant LAE effects; however, increased numbers of invertebrates drifted in the 5.15-mg/L streams compared to controls. The 30-d LC50 for farm-raised and University-cultured fathead minnows was similar at 1.27 mg/L. The 30-d survival NOEC and LOEC for both populations of fish were 0.88 mg/L and 1.99 mg/L, respectively. There were no significant effects on reproduction in University-cultured fathead minnow. Fathead minnow reproductive behavior and feeding behavior were most susceptible to surfactant exposure with a NOEC of 0.32 mg/L. Bluegill sunfish survival responded similarly to the LAE as fathead minnow with a 30-d NOEC of 0.88 mg/L. No sublethal effects on juvenile bluegill growth were observed in this study. For primarily regulatory purposes, a “mesocosm NOEC” of 0.28 mg/L was derived for use in risk assessment.
Dietary accumulation and depuration of hydrophobic organochlorines: Bioaccumulation parameters and their relationship with the octanol/water partition coefficient
Authors: Fisk Aaron T , Norstrom Ross J , Cymbalisty Chris D , Muir Derek C.G
Published: February 2010

Dietary accumulation of 23 hydrophobic organochlorines (OCs) by juvenile rainbow trout (Oncorhynchus mykiss) was studied with the objective of obtaining relationships between bioaccumulation parameters and the octanol/water partition coefficient (Kow). A wide range of OCs were used including 16 polychlorinated biphenyls (PCBs 18, 28, 44, 52, 66, 101, 105, 118, 128, 138, 153, 187, 189, 195, 206, and 209), hexachlorobenzene, mirex, tris(4-chlorophenyl)methane (TCPMe), tris(4-chlorophenyl)methanol (TCPMeOH), and three toxaphene congeners (Cl7-chlorobornane [CHB] [Hp-sed], Cl8-CHB [T2], and Cl9-CHB [T12]). Tris(4-chlorophenyl)methane (half-life [t1/2] = 65 d) was more persistent than TCPMeOH (t1/2 = 20 d), and TCPMe was not biotransformed to TCPMeOH by rainbow trout. Cl7-chlorobornane (t1/2 = 32 d) was more rapidly eliminated, and appears to be more readily metabolized, than Cl8-CHB (t1/2 = 43 d) and Cl9-CHB (t1/2 = 42 d). With the exception of TCPMeOH, Cl7-CHB, and PCB 18, all of the OCs had biomagnification factors (BMFs) >1, implying a potential to biomagnify. Half-lives had a significant curvilinear relationship with Kow (R2 = 0.85, p < 0.001), with a maximum t1/2 for OCs with log Kow ∼ 7.0. Decreasing t1/2 for OCs of log Kow > 7.0 may be related to slow kinetics of these super hydrophobic OCs and the short exposure phase, which results in insufficient time for the super hydrophobic OCs to reach slower clearing compartments of the rainbow trout. Assimilation efficiency was not as well described by Kow as by t1/2 and BMF, although a significant curvilinear relationship was observed (R2 = 0.53, p = 0.004). The BMF had a significant curvilinear relationship with log Kow (R2 = 0.84, p < 0.001). Recalcitrant OCs with a log Kow of ∼7.0 would appear to have the greatest potential for food chain biomagnification in fish.
Methyl sulfonyl polychlorinated biphenyls and 2,2-bis(4-chlorophenyl)-1,1-dichlorethenein gray seal tissues determined by gas chromatography with electron capture detection and atomic emission detection
Authors: Janák Karel , Becker Gerhard , Colmsjö Anders , Östman Conny , Athanasiadou Maria , Valters Karlis , Bergman Åke
Published: February 2010

The presence of 24 methyl sulfonyl polychlorinated biphenyl (PCB) congeners (MeSO2-CBs) and 3-methyl sulfonyl 2,2-bis(4-chlorophenyl)-1,1-dichlorethene (DDE) (MeSO2-DDE), metabolites of PCB and DDE, in blubber, lung, and liver of gray seals has been determined by using atomic emission detection (AED) and electron capture detection (ECD). Selective accumulation of aryl methyl sulfones in blubber, liver, and lung tissue was also investigated. For the liver samples, a substantial and highly specific retention of PCB methyl sulfones was observed. The atomic emission technique significantly improved the determination of measured solutes compared with ECD. Atomic emission detection was also valuable for the monitoring of the prefractionation and to decrease the requirements of sample clean-up. Comparing both detection techniques showed a good correlation between the results of the AED sulfur-selective line and ECD.
Effect of mixtures of polycyclic aromatic hydrocarbons and sediments on fluoranthene biodegradation patterns
Authors: Beckles Denise M , Ward C Herb , Hughes Joseph B
Published: February 2010

The biodegradation of fluoranthene, alone and in mixtures with naphthalene and acenaphthene, was studied in systems with and without sediments. In sediment-free systems, fluoranthene was not degraded when present alone or in combination with acenaphthene but was degraded when combined with naphthalene. Naphthalene and acenaphthene degradation were not influenced by fluoranthene. In sediment-containing systems, fluoranthene degradation occurred only in the presence of naphthalene. After complete degradation of naphthalene, fluoranthene degradation stopped. Experiments using all three polycyclic aromatic hydrocarbons in both sediment-free and -containing systems showed results similar to those obtained using pairs.
Persistent organochlorine contaminants in ringed seals (Phoca hispida) from the Kara Sea, Russian Arctic
Authors: Nakata Haruhiko , Tanabe Shinsuke , Tatsukawa Ryo , Koyama Yasuhiro , Miyazaki Nobuyuki , Belikov Stanislav , Boltunov Andrei
Published: February 2010

Ringed seals collected from the KaraSea in the Russian Arctic during 1995 were analyzed for persistent organochlorines (OCs) such as DDTs, polychlorinated biphenyls (PCBs), chlordane compounds (CHLs), hexachlorocyclohexanes (HCHs), and hexachlorobenzene to understand the present status of contamination. Noticeably higher levels of DDTs and PCBs were detected in ringed seals from the Russian Arctic when the values compared with same species from the Canadian Arctic and the Norwegian Arctic. This suggests the presence of significant local sources of DDTs and PCBs in Russia or nearby areas. Concentrations of CHLs and HCHs in ringed seals were comparable with those in this species elsewhere in circumpolar regions, probably as a consequence of uniform distribution of CHLs and HCHs due to the atmospheric transport of these compounds to the Arctic region. Larga seals collected from the Sea of Okhotsk were also analyzed for OCs to compare residue levels and accumulation patterns with those in ringed seals. In larga seals, the prominent residues were DDTs and PCBs, with levels comparable or slightly lower than those in ringed seals. Lactational transfer of PCBs, DDTs, and CHLs was evident in ringed seals based on increasing concentrations with age in males but not in females. The transfer rates were estimated to be 38% for DDTs, 25% for PCBs, and 30% for CHLs of the whole body burden in the mature female. Comparison of the PCB congener pattern accumulated in seals suggested that ringed seals have an greater capacity to degrade toxic non-ortho (IUPAC 126) and mono-ortho (IUPAC 105 and 118) coplanar congeners than did Baikal seals, but a lower capacity than found in larga seals.
Sensitivity of fish embryos to weathered crude oil: Part II. Increased mortality of pink salmon (Oncorhynchus gorbuscha) embryos incubating downstream from weatheredExxon valdezcrude oil
Authors: Heintz Ron A , Short Jeffrey W , Rice Stanley D
Published: February 2010

We incubated pink salmon embryos under three exposure conditions, direct contact with oil-coated gravel, effluent from oil-coated gravel, and direct contact with gravel coated with very weathered oil (VWO). Embryo mortalities and polynuclear aromatic hydrocarbon (PAH) accumulation in embryo tissues during the direct-contact and effluent exposure experiments were not significantly different, indicating that PAH accumulation was mediated by aqueous transport. Mortality rates for embryos exposed initially to a total PAH concentration (TPAH) of 1.0 ppb were significantly higher than controls when the PAH were derived from VWO. The same aqueous TPAH concentration failed to increase mortality rates when the PAH were derived from less weathered oil, indicating that toxicity of effluents from the VWO was primarily associated with the larger PAH. We conclude that water quality standards for TPAH above 1.0 ppb may fail to protect fish embryos. Further, pink salmon embryos incubating in Prince William Sound after the Exxon Valdez oil spill may have accumulated lethal concentrations of PAH from interstitial water that was contaminated when it percolated through oil reservoirs located upstream from salmon redds.
Improved method for estimating bioconcentration/bioaccumulation factor from octanol/water partition coefficient
Authors: Meylan William M , Howard Philip H , Boethling Robert S , Aronson Dallas , Printup Heather , Gouchie Sybil
Published: February 2010

A compound's bioconcentration factor (BCF) is the most commonly used indicator of its tendency to accumulate in aquatic organisms from the surrounding medium. Because it is expensive to measure, the BCF is generally estimated from the octanol/water partition coefficient (Kow), but currently used regression equations were developed from small data sets that do not adequately represent the wide range of chemical substances now subject to review. To develop an improved method, we collected BCF data in a file that contained information on measured BCFs and other key experimental details for 694 chemicals. Log BCF was then regressed against log Kow and chemicals with significant deviations from the line of best fit were analyzed by chemical structure. The resulting algorithm classifies a substance as either nonionic or ionic, the latter group including carboxylic acids, sulfonic acids and their salts, and quaternary N compounds. Log BCF for nonionics is estimated from log Kow and a series of correction factors if applicable; different equations apply for log Kow 1.0 to 7.0 and >7.0. For ionics, chemicals are categorized by log Kow and a log BCF in the range 0.5 to 1.75 is assigned. Organometallics, nonionics with long alkyl chains, and aromatic azo compounds receive special treatment. The correlation coefficient (r2 = 0.73) and mean error (0.48) for log BCF (n = 694) indicate that the new method is a significantly better fit to existing data than other methods.
Life-cycle framework for assessment of site remediation options: Case study
Authors: Page Cynthia A , Diamond Miriam L , Campbell Monica , McKenna Stephen
Published: February 2010

An adaptation of life-cycle assessment for contaminated site remediation activities was used to examine a lead-contaminated site remediated by excavation and disposal. The study indicated emissions and impacts associated with energy consumption (transportation of contaminated soil to hazardous and nonhazardous sites), solid waste production (contaminated soil and sludge), land use at four sites (the contaminated site, two disposal sites, and a borrow pit for clean fill), and potential toxicity from emissions and contaminants remaining on-site. These impacts were drawn from an inventory compiled mainly from proprietary consultants' reports, and related to impacts through several stressor–impact models; the process-related indicators of global warming potential, solid waste burden, and ecological and human toxicity potential; and site-related indicators of land use and residual human toxicity burden. Ecological and human toxicity potentials were estimated using the Mackay level III model for southern Ontario, Canada, adapted for metals. The life-cycle approach proved useful for identifying potential impacts occurring at local, regional, and global scales, over all activities and locations affected by the remediation.
Enhanced anaerobic biotransformation of carbon tetrachloride in the presence of reduced iron oxides
Authors: Kim Sanggoo , Picardal Flynn W
Published: February 2010

Rates of anaerobic transformation of carbon tetrachloride (CT) by the facultative anaerobe Shewanella putrefaciens 200 were increased by the presence of Fe(III)-containing minerals. In batch reactors with amorphous, Fe(III)-hydroxide and S. putrefaciens, CT transformation rates could be modeled by a first—order expression in which the pseudo—first-order rate constant was linearly proportional to the initial concentration of Fe(III)-oxide. Subsequent measurement of soluble and acid—extractable Fe(II) showed that increased CT transformation rates were proportional to microbially reduced, surface—bound Fe(II), rather than soluble Fe(II). In biomimetic experiments using 20 mM dithiothreitol (DTT) as a reductant, rates of transformation of CT by DTT were low in the absence of Fe(III)-oxides. However, in the presence of iron oxides, DTT was able to transform CT at elevated rates. Results again strongly suggested that surface—bound Fe(II) was primarily responsible for the reductive transformation of CT. Results suggested that the surface area of the iron mineral determines the rate of CT transformation by affecting the extent of iron reduction. Chloroform (CF) was the only transformation product identified and production of CF was nonstoichiometric. In microbial and abiotic experiments with Fe(III) oxides, the percentage of the transformed CT recovered as CF decreased even though the rate and extent of CT transformation was increased. Overall, our results have important implications for an improved understanding of possible microbial and geochemical interactions in the environmental transformation of chlorinated organic pollutants and for modeling of CT transformation rates in anaerobic, iron—bearing sediments.
Assessment of sediment contamination, acute toxicity, and population viability of the estuarine amphipodLeptocheirus plumulosusin baltimore harbor, maryland, USA
Authors: McGee Beth L , Fisher, Daniel J , Yonkos Lance T , Ziegler Gregory P , Turley Steve
Published: February 2010

In Chesapeake Bay, Maryland, USA, some of the most contaminated sediments are found in the highly industrialized Baltimore Harbor—Patapsco River area. As part of a comprehensive assessment of sediment quality in this system, sediment toxicity was assessed in 10-d acute tests with the estuarine amphipod Leptocheirus plumulosus. Mean amphipod survival was significantly reduced in 7 of the 25 samples tested despite the occurrence of minor experimental artifacts. The most toxic sediments were collected from Bear Creek; other areas exhibiting toxicity included the Inner Harbor and Colgate Creek. Marginal toxicity was observed in samples from Curtis Creek, Lazeretto Point, and Back River. Negative relationships were detected between survival and concentrations of select sediment—associated contaminants, whereas a very strong positive association existed between survival in laboratory exposures and density of L. plumulosus at the test sites. A weight of evidence approach, including correlation analyses, a model of polycyclic aromatic hydrocarbon bioavailability, and comparisons to benchmark sediment levels, was used to tentatively identify classes of contaminants that contributed to the observed toxicity. Analysis of results suggested that toxicity at stations in Bear Creek and Colgate Creek may have been driven by sediment—associated metals, whereas toxicity at stations in the Inner Harbor was likely due to both metal and organic contaminants. The observed relationships among toxicity test results, concentrations of sediment—associated contaminants, and abundance of L. plumulosus at the test sites suggests that acute toxicity tests with this species are indicative of adverse biological effects in the field.
Diel cycles in calcite production and dissolution in a eutrophic basin
Authors: Cicerone, Daniel S , Stewart Arthur J , Roh Yul
Published: February 2010

Calcite production is understood largely as a longer—term phenomenon (e.g., seasonal whitings) that can occur in hardwater lakes, and is significant ecologically because it can slow the rate of eutrophication by reducing, through adsorption, the availability of nutrients to primary producers. In this study we show that rapid changes in concentration of dissolved CO2 by photosynthesis and respiration within a eutrophic basin generated strong day—to-night cycles in calcite production and dissolution. Diel cycles in calcite production and dissolution were large enough that they could drive secondary diel cycles in the availability of metals that strongly sorb to the surfaces of calcite particles. We explored the possibility of the secondary diel cycling of metals by intensive 7-d in situ monitoring of water—quality conditions in a shallow, eutrophic spill—control basin near an industrial facility in eastern Tennessee; inspecting data from a 7-year record of water—quality parameters for this basin; analyzing physicochemical characteristics and mineralogic composition of sediments in the basin; and conducting laboratory experiments to characterize the interaction of calcite with Cd, under solid—liquid nonequilibrium conditions. We found that the basin accumulated and stored calcite. In situ monitoring showed that calcite was produced during daylight, and tended to dissolve again at night; the calcite production and dissolution processes seemed to be modulated by dissolved—phase CO2 dynamics, in concert with large diel fluctuations in pCa, pH, and PO2. Laboratory experiments showed a rapid interaction (<6 h) of Cd with calcite, in response to dissolved CO2 changes. Thus, concentrations of dissolved Cd can vary over daily cycles, mediated by diel changes in calcite production and dissolution. Thermodynamic considerations suggest that other metals, such as Zn, Sr, Ni, and Ba, may demonstrate this behavior as well.
Comparison ofBrachionus calyciflorus2-d and microtox® chronic 22-h tests withDaphnia magna21-d test for the chronic toxicity assessment of chemicals
Authors: Radix Pascal , Léonard Marc , Papantoniou Christos , Roman Gilles , Saouter Erwan , Gallotti—Schmitt Sophie , Thiébaud Hervé , Vasseur Paule
Published: February 2010

The Daphnia magna 21-d test may be required by European authorities as a criterion for the assessment of aquatic chronic toxicity for the notification of new substances. However, this test has several drawbacks. It is labor—intensive, relatively expensive, and requires the breeding of test organisms. The Brachionous calyciflorus 2-d test and Microtoxr̀ chronic 22-h test do not suffer from these disadvantages and could be used as substitutes for the Daphnia 21-d test for screening assays. During this study, the toxicity of 25 chemicals was measured using both the Microtox chronic toxicity and B. calyciflorus 2-d tests, and the no—observed-effect concentrations (NOECs) were compared to the D. magna 21-d test. The Brachionus test was slightly less sensitive than the Daphnia test, but the correlation between the two tests was relatively good (r2 = 0.88). On average, the Microtox chronic test presented the same sensitivity as the Daphnia test, but the results did not correlate as well (r2 = 0.54). The B. calyciflorus 2-d test, and to a lesser extent the Microtox chronic 22-h test, were able to predict the chronic toxicity values of the Daphnia 21-d test. They constitute promising cost—effective tools for chronic toxicity screening.
Pyrene metabolites in the hepatopancreas and gut of the isopod porcellio scaber, a new biomarker for polycyclic aromatic hydrocarbon exposure in terrestrial ecosystems
Authors: Stroomberg, Gerard J , Knecht Joop A DE , Ariese Freek , Gestel Cornelis AM Van , Velthorst Nel H
Published: February 2010

The object of this study was to investigate the formation of pyrene metabolites by the isopod Porcellio scaber as a possible tool in the environmental risk assessment of polycyclic aromatic hydrocarbon (PAH) exposure in terrestrial ecosystems. The formation of pyrene metabolites was studied after either pulse exposure to a single high dose, or prolonged exposure (14 d) to a lower dosage. Exposure studies were carried out with unlabeled or radiolabeled pyrene, ion pair chromatography was used for analysis, and reference conjugates were synthesized. We also measured pyrene metabolites in field—exposed animals, to explore their use as biomarkers of PAH exposure. Analysis of the hepatopancreas and gut of single isopods revealed the formation of five products, one of which was 1-hydroxypyrene. Four of the remaining products were identified as phase II metabolites of 1- hydroxypyrene, with UV absorption and fluorescence characteristics similar to that of pyrene. One metabolite was identified as pyrene−1-glucoside, which is in accordance with high rates of glucosidation, reported for these isopods. Another conjugate was identified as pyrene−1-sulfate. None of the metabolites coeluted with a pyrene−1-glucuronide reference obtained from fish bile. A fifth metabolite detected by on—line scintillation detection did not exhibit any absorption at 340 nm, possibly because one of the aromatic rings of pyrene had lost its aromatic character. Although pyrene is not known for its toxicity, it usually co—occurs with other PAHs that are transformed into toxic products. Investigating the metabolism of pyrene can provide information with regard to the biotransformation capacity of invertebrate species and uptake and elimination kinetics. Because pyrene is one of the most predominant PAHs in the environment, analysis of its metabolites provides an extra tool for the environmental risk assessment of ecosystems with regard to PAH exposure, bioavailability, and biotransformation.
Validity and ecological relevance of an active in situ bioassay using gammarus pulex and limnephilus lunatus
Authors: Schulz Ralf , Liess Mathias
Published: February 2010

In situ bioassays using aquatic organisms serve as a link between laboratory and field studies. However, the ecological relevance of in situ studies had not previously been assessed by direct comparison with field data. In this study, an in situ bioassay employing Gammarus pulex L. (Crustacea: Amphipoda) and Limnephilus lunatus Curtis (Insecta: Trichoptera) was used in two agricultural tributaries and the connecting headstream. Simultaneously, the short—term insecticide contamination and the stream population dynamics of both species were monitored. During transient insecticide inputs (duration: about 1 h; peak concentrations: 6.2 mg/L fenvalerate; 0.6 μg/L parathion—ethyl), mortality of both species in the in situ bioassay was significantly higher in the contaminated tributary than in the uncontaminated control tributary (analysis of variance [ANOVA], Fisher's protected least significant difference [PLSD]; p < 0.05). Limnephilus lunatus gave comparable responses in the stream; however, no mortality of G. pulex was observed in the stream. The reason for this difference is presumably that, in contrast to the bioassay, a typical avoidance behavior of G. pulex to pesticides, downstream drift, is possible in the field. During runoff events, G. pulex migrated from the potentially contaminated headstream section into the uncontaminated tributary, which can be regarded as a refuge and source for recolonization. Significantly lower coefficients of variance in the bioassay (≤0.22 compared to ≥0.55 in the field samples) allow for a better detection of adverse effects of pesticide with this method. Hence, although the bioassay is valuable for identifying insecticide input events, supplementary field studies are necessary for an ecological interpretation of the results.
Qualitative assessment of genotoxicity using random amplified polymorphic DNA: Comparison of genomic template stability with key fitness parameters inDaphnia magnaexposed to benzo[a]pyrene
Authors: Atienzar Franck A , Conradi Mercedes , Evenden Andrew J , Jha Awadhesh N , Depledge Michael H
Published: February 2010

A method of DNA profiling using the random amplified polymorphic DNA (RAPD) was used to assess toxicant—induced DNA effects in laboratory populations of Daphnia magna exposed to varying concentrations of the genotoxic hydrocarbon benzo[a]pyrene. These effects, represented by changes in the RAPD profiles, were compared with a number of key ecological fitness parameters (age—specific survival, age—specific fecundity, net reproductive rate, and intrinsic rate of population increase). Not only was the RAPD profiling method shown to be a rapid and reproducible assay of toxicant—induced DNA effects, but the qualitative measure of genomic template stability compared favorably with the traditional indices of fitness. The RAPD profiles, however, exhibited higher sensitivity in detecting toxic effects. The significance of these findings for future ecotoxicological studies is discussed.
Bioavailability of cadmium and zinc to the common carp, CYPRINUS carpio, in complexing environments: A test for the validity of the free ion activity model
Authors: Ginneken Luc Van , Chowdhury Mohammed J , Blust Ronny
Published: February 2010

The uptake of cadmium and zinc by the common carp, Cyprinus carpio, was studied in chemically defined freshwater in the presence of different organic ligands (i.e., citrate, glycine, histidine, ethylenediaminetetraacetic acid, and nitrilotriacetic acid). In most cases, metal complexation decreased Cd and Zn uptake by reducing the free Cd and Zn ion activity. However, Cd and Zn uptake did not increase linearly with the free Cd and Zn ion activity in the solution. A good fit to the data was obtained when the observations were fitted to a Michaelis—Menten-like model for carrier—mediated transport of the metal ions across the biological interface. In addition, the uptake of Cd in the presence of citrate, glycine, and histidine was markedly higher than expected on the basis of the free Cd ion activity. It was concluded that cadmium complexes of these low molecular weight, hydrophilic ligands contributed to the Cd bioavailability, probably by direct uptake of these complexes. Zinc uptake in the presence of the complexing agents could be predicted on the basis of the ambient free Zn ion activity, although uptake in the presence of citrate was lower than expected on the basis of the free Zn ion activity. These results provide a challenging test for the free ion activity model.
Organochlorine contaminants in mummichog (Fundulus heteroclitus) living downstream from a bleachedkraft pulp mill in the Miramichi Estuary, New Brunswick, Canada
Authors: Couillard Catherine M , Nellis Pierre
Published: February 2010

Mummichog, a small-sized sentinel fish species, has been proposed for use in environmental effects monitoring programs conducted by pulp mills that release their effluent in marine waters. In order to evaluate the suitability of mummichog as a sentinel species and to support the interpretation of biological effects data, tissue concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans, (PCDD/Fs), chlorophenolic compounds (CPs), polychlorinated biphenyls (PCBs), and chlorinated pesticides were investigated in mummichog sampled in the Miramichi Estuary, which was receiving a bleached-kraft mill (BKM) effluent, and in a reference estuary, the Bouctouche Estuary. Higher concentrations PCDD/Fs (up to 50 times), CPs (up to 60 times), DDT, and PCBs (up to 10 times) were found in mummichog sampled at the upstream site of the Miramichi Estuary. At this site, 2,3,7,8- tetrachlorodibenzo-p-dioxin toxic equivalent concentrations were slightly above the threshold for ethoxy resorufin O-deethylase induction. Multivariate analyses on congener profiles revealed that the contamination by PCDD/Fs and CPs originated both from the BKM and from a former wood-preservation plant and that PCDD/Fs and CPs typical of the BKM were transported 40 km downstream from the mill. Patterns and levels of persistent contaminants differed between sites within the Estuary, indicating that the fish did not mix during their growing period. These findings support the use of mummichog in environmental effects monitoring programs, because this species bioaccumulates chlorinated compounds contained in BKM effluent and is sedentary. The cause-effect relationship between exposure to the BKM effluent and the observed biological responses will have to be demonstrated by laboratory studies because of the presence of multiple sources of contamination.
Dietary zinc reduces uptake but not metallothionein binding and elimination of cadmium in the springtail, Orchesella cincta
Authors: Sterenborg Ingrid , Vork Nicole A. , Verkade Sebastiaan K. , van Gestel Cornelis A. M. , van Straalen Nico M.
Published: February 2010

In metal-polluted environments, high concentrations of metals such as zinc, cadmium, copper, and lead are present. Many studies have been conducted to determine uptake and binding of the nonessential, toxic metal cadmium. Effects of essential metals on this uptake and binding remain unclear. The aim of the present study was to determine the effect of zinc on cadmium kinetics and metallothionein induction in the springtail Orchesella cincta. Exposure experiments were conducted with cadmium only, zinc only, and cadmium + zinc. Metallothionein was isolated to determine zinc binding to or induction of this cadmium-binding protein. In animals exposed to cadmium only and to cadmium + zinc, metallothionein was induced. In animals exposed to zinc only, no metallothionein was induced, and zinc did not bind to the metallothionein induced by cadmium. Cadmium uptake rate was significantly lower in animals exposed to cadmium + zinc than in animals exposed to cadmium only. No significant pattern of uptake and elimination of zinc was observed. Zinc concentrations in the animals were not significantly different for the different exposures, demonstrating that this element is regulated by O. cincta. These results suggest a protective role of zinc in the uptake of cadmium but no interference of zinc with the internal cadmium distribution and elimination.
The missing biomarker link: Relationships between effects on the cellular energy allocation biomarker of toxicant-stressedDaphnia magnaand corresponding population characteristics
Authors: De Coen Wim M. , Janssen Colin R.
Published: February 2010

The cellular energy allocation (CEA) methodology was used to assess the adverse effects of toxic stress on the energy budget of test organisms. This biochemical assay is quantified by determining changes in the available energy reserves, Ea (total carbohydrate, protein, and lipid content) and the energy consumption, Ec (electron transport activity). The CEA methodology was fully explored by using neonates of Daphnia magna exposed for 96 h to six model toxicants (CdCl2, K2Cr2O7, tributyltin chloride, linear alkylbenzene sulfonic acid, sodium pentachlorophenolate, and 2,4-dichlorophenoxyacetic acid). To evaluate the ecological relevance of the CEA parameter, we compared the suborganismal responses with population-level parameters (obtained from 21-d life-table experiments) such as the intrinsic rate of natural increase (rm) and the mean total offspring per female. The observed reductions in CEA values were both the result of a decrease in Ea and an increase in Ec. From all individual CEA components analyzed, the lipid reserve criterion was the most sensitive endpoint studied. Both the CEA-based lowest-observed-adverse-effect concentration (LOAEC) values and the effective concentration of 10% (EC10) values were significantly (p < 0.05) and linearly correlated with the chronic (21-d) LOAEC and EC10 values based on growth, survival, and reproduction. This relationship demonstrates the usefulness of the methodology to predict long-term effects. Furthermore, significant (p < 0.0001) sigmoid relationships between the 96-h CEA value (expressed as percentage relative to the control) and population-level effects were observed.