bluuebunny/crossref_metadata_2025 huggingface dataset:
Silver speciation in wastewater effluent, surface waters, and pore waters
Authors: Adams Nicholas W H , Kramer James R
Published: March 2010

Silver, inorganic sulfide, and thiol compounds were measured in municipal wastewater effluent, receiving waters, and pore waters from an anoxic lake sediment in order to predict silver speciation in these systems. We found submicromolar concentrations of inorganic sulfide even in fully oxic surface water. This inorganic sulfide is likely to exist in the form of colloidal metal sulfides, which have been shown to be stable under oxidizing conditions for periods of several hours. Inorganic sulfide in both the wastewater effluent and receiving waters was found to be 200 to 300 times in excess of silver concentrations, whereas inorganic sulfide in the pore waters was 1,000 to 15,000 times in excess of silver concentrations. With sulfide in excess of silver, we predict silver sulfide complexes to dominate silver speciation. Thiols were present at low nanomolar levels in pore waters but were not detectable (<1 nM) in wastewater effluent or receiving waters. Thiols do not appear to be important to silver speciation in these freshwater systems. Partitioning of silver into particulate (>0.45 μm), colloidal (10 kDa, 0.45 μm), and dissolved (<10 kDa) size fractions showed that a significant proportion of silver is in the colloidal (30–35%) and dissolved phases (15–20%). Dissolved phase concentrations were relatively constant in the treatment plant effluent and receiving waters, suggesting that silver in the <10-kDa size fraction is strongly complexed by ligands that are not significantly affected by aggregation or sorption processes.
Bioconcentration and biotransformation of the nonionic surfactant octaethylene glycol monotridecyl ether 14C-C13EO8
Authors: Tolls Johannes , Sijm Dick THM.
Published: March 2010

Alcohol ethoxylates (AEs) are the most important nonionic surfactants used in household detergents. In this study, we investigated the bioconcentration behavior of 14C-labeled C13EO8 as a representative of AEs in fathead minnow (Pimephales promelas). The rate constants of uptake and elimination of the parent 14C-C13EO8 were 317 L/kg/d and 10.1/d, respectively. The parent compound-specific bioconcentration factor (BCF) was found to be 31.4 L/kg. In contrast, the steady-state ratio of the concentrations in fish and water (Cf,tot/Cw,tot)ss of total radioactivity was 224 L/kg. The thin layer chromatography chromatograms demonstrated that the 14C-C13EO8-derived radioactivity is incorporated into a large variety of chemical species. This, as well as the large discrepancy between the BCF and (Cf,tot/Cw,tot)ss are qualitative indicators of the extent of biotransformation. The first-order, one-compartment model of bioconcentration was extended to allow for quantification of the in vivo rate constant of biotransformation of 14C-C13EO8. The value obtained amounted to 10/d, and the model results indicated that biotransformation is the dominating contributor in the elimination of AEs. A comparison of C13EO8 to compounds of other classes of environmentally relevant contaminants highlights the importance of biotransformation as a process contributing to the reduction of the bioconcentration potential of these compounds.
Mild extractability and bioavailability of polycyclic aromatic hydrocarbons in soil
Authors: Tang Jixin , Alexander Martin
Published: March 2010

A study was conducted to determine the relationship between bioavailability of unaged and aged polycyclic aromatic hydrocarbons (PAHs) in soil and the amounts detected by mild solvent extraction. More aged than unaged anthracene remained in Lima loam following introduction of earthworms (Eisenia foetida), a mixed culture containing anthracene-degrading microorganisms, or earthworms or wheat after bacterial biodegradation of the compound. Aging decreased the percentage of anthracene recovered by mild extraction with n-butanol from soil following introduction of earthworms, growth of wheat, biodegradation by bacteria, or when maintained sterile. Biodegradation resulted in a marked decrease in the percentage of aged and unaged anthracene recovered from soil by mild extraction with n-butanol or ethyl acetate. Aging of fluoranthene and pyrene decreased the amount removed by mild extraction with n-butanol, ethyl acetate, and propanol. The uptake of aged and unaged anthracene, fluoranthene, and pyrene by earthworms was correlated with the amounts recovered from soil by mild extraction with n-butanol, propanol, and ethyl acetate (r values in the range 0.911–0.992). The retention of aged and unaged anthracene by wheat and barley was correlated with the amounts recovered from soil by the same procedure (r values in the range 0.892–0.945). We suggest that mild extraction with organic solvents can be used to predict the bioavailability of PAHs in soil.
Summertime transport of current-use pesticides from California's Central Valley to the Sierra Nevada Mountain Range, USA
Authors: LeNoir James S , McConnell Laura L , Fellers Gary M , Cahill Thomas M , Seiber James N
Published: March 2010

Aricultural activity in California's Central Valley may be an important source of pesticides that are transported in the air to the Sierra Nevada Mountain Range, USA. Pesticides applied to this intensive crop production area may volatilize under warm temperatures typical of the valley and be transported through the atmosphere to be deposited in the cooler, higher elevation regions of the Sierra Nevada Mountains. To determine the extent of summertime atmospheric transport of pesticides to this region, high-volume air, dry deposition, and surface water samples were collected in the Central Valley and at different elevations in California's Sequoia National Park. Results revealed that the highest residue concentrations were those of compounds with heavy summertime agricultural use. A significant drop in pesticide concentrations in both air and water samples was observed within a few 100-m elevation from the valley; however, levels remained relatively constant between ∼500 and 2,000 m. Water concentrations from two areas above 3,000 m contained levels less than a tenth as high as those at lower elevations. Possible effects of the pesticides were estimated using measured water concentrations to calculate total exposure of three aquatic species to organophosphate insecticides. Aggregate exposure calculations showed concentrations were well below 96-h LC50 values for rainbow trout and stonefly but concentrations may be harmful to amphipods.
Bioavailability of labile and desorption-resistant phenanthrene sorbed to montmorillonite clay containing humic fractions
Authors: Lahlou Mohammed , Ortega-Calvo Jose Julio
Published: March 2010

The biodegradation of 14C-labeled phenanthrene in the presence of particles of montmorillonite and fulvic and humic acid–montmorillonite complexes was studied in a batch system. A mathematical model that takes into account the contribution to mineralization by the slowly desorbing compound was used to calculate the initial mineralization rates. Sorption of phenanthrene to the particles was determined in sorption isotherms, and desorption was measured during successive water extractions. Mineralization rates in equilibrated suspensions were higher than predicted from aqueous equilibrium concentrations, and in some cases, montmorillonite and fulvic acid–montmorillonite complexes stimulated the phenanthrene transformation rates. In contrast with the high bioavailability exhibited by phenanthrene sorbed as a labile form, biodegradation of the desorption-resistant phenanthrene occurred slowly and followed zero-order kinetics, which indicated a limitation caused by slow desorption. The results suggest that the mechanism of sorption may cause a differential bioavailability of the sorbed compound.
Bioavailability of freshly added and aged naphthalene in soils under gastric pH conditions
Authors: Jin Zhaowei , Simkins Stephen , Xing Baoshan
Published: March 2010

The bioavailability of hydrophobic organic chemicals decreases with aging in soil because of sequestration. However, assessments of the risk of exposure to contaminated soils are usually dependent on either chemical concentrations, which are measured using vigorous extraction methods, or models that assume an equilibrium without considering the actual conditions. The objective of this research was to determine the availability and desorption kinetics of freshly added and aged naphthalene from a peat and a mineral soil; naphthalene was desorbed into solutions with pH levels that approximate those found in different gastric regions. Soil and peat samples were spiked with radiolabeled and unlabeled naphthalene at 2 and 20 μg/g and were aged from 0 to 135 d. Desorption kinetics were determined using a simulated stomach solution (0.1 M NaCl, 0.1 M HCl, 0.01 M NH4Ac, pH = 1.0) and a neutral solution (0.2 M NaCl, pH = 6.7) that represented the pH of intestinal conditions and most soils. Peat sorbed much more naphthalene than did soil, and it allowed little desorption. Though both acidic and neutral extracting solutions could desorb naphthalene, little apparent effect of aging was observed in peat, whereas desorption from soil declined markedly with aging. In addition, the percentage of naphthalene that desorbed from soil was greater for the higher incubation concentration. The desorption of naphthalene from the peat and soil was higher into the neutral solution than into the gastric solution. These results suggest that aging, exposure conditions, concentration effect, and organic matter content should be taken into account in predictive models and risk assessments.
Membrane toxicity of linear alcohol ethoxylates
Authors: Müller Markus T , Zehnder Alexander JB , Escher Beate I
Published: March 2010

The membrane toxicity of linear alcohol ethoxylates (AEO/single reference compounds and technical mixtures) was investigated with an in vitro method based on time-resolved spectroscopy on energy-transducing membranes. The nonspecific membrane perturbation of narcotic chemicals can be quantified by the degree of disturbance of buildup and relaxation of the membrane potential in membrane preparations of the purple bacterium Rhodobacter sphaeroides. The effect concentrations obtained for this narcotic effect correlated well with the results from various toxicity tests on whole organisms. In addition, the effect concentrations at the target site, the biological membrane, were derived from the nominal effect concentrations using membrane-water partition coefficients. The test set of linear AEO comprised compounds with an alkyl chain length of 8 to 16 carbon units and 5 to 14 ethoxylate (EO) units covering more than four orders of magnitude of hydrophobicity (expressed as octanol–water partition coefficient). All AEO exhibited their toxic effect at concentrations well below the critical micelle concentration. When comparing aqueous effect concentrations, toxicity increased strongly with increasing length of the alkyl chain and showed a small parabolic dependence on the number of EO units with a maximum at eight EO units. With the toxic effect expressed in terms of membrane concentrations, all AEO exhibited similar activity in the concentration range typical for narcotic chemicals. The toxic membrane concentrations of AEO with 5 and ≥8 EO units were 200 and 60 mmol/kg lipid, which correspond to the critical body residues of nonpolar and polar narcotics in fish, respectively. In addition, the toxic effects of mixtures of AEO were measured and could be modeled as the sum of activities of the single constituents, confirming the concept of concentration additivity of compounds with the same mode of toxic action.
Enantioselective determination of two persistent chlorobornane congeners in sediment from a toxaphene-treated yukon lake
Authors: Vetter Walter , Bartha Richard , Stern Gary , Tomy Gregg
Published: March 2010

The composition of toxaphene residuesand the enantiomeric ratios of the major congeners were studied in the top 10 slices (1935–1992) of a sediment core collected from Hanson Lake in the Yukon Territories (Canada). This lake was treated with toxaphene as a picsicide in July 1963. Electron-capture negative ion mass spectrometry and electron-capture detection were applied in combination with enantioselective gas chromatography using modified cyclodextrin columns. Of the 10 toxaphene peaks identified in each of the sediment slices, two congeners, 2-exo,3-endo,6-exo,8,9,10-hexachlorobornane (B6-923 or Hx-Sed) and 2-endo,3-exo, 5-endo,6-exo, 8,9,10-heptachlorobornane (B7-1001 or Hp-Sed), were the most abundant. Each of the three chiral stationary phases used in this study was successful at resolving the enantiomers in at least of one of the two congeners. Among them was permethylated β-cyclodextrin (Chirasil-Dex), which, up until now, has never been used for enantiomer separation of compounds of technical toxaphene. B6-923 and another less abundant, as of yet unknown, hexachlorobornane were racemic in all sediment core slices. For B7-1001, the latter eluting enantiomer was always more predominant. Furthermore, the enantiomeric ratio was found to consistently decrease with time from approximately 0.8 in the early slices (∼1950) to 0.7 in the slice representing 1992, implying that the first eluted B7-1001 enantiomer is less persistent than the second. B6-923 and B7-1001 are most likely metabolites of the more highly chlorinated congeners. A structural evaluation provided evidence that reductive dechlorination at carbons with geminal chlorine atoms is the primary microbial degradation pathway in sediments from Hanson Lake.
Thyroidal status of mummichogs (Fundulus heteroclitus) from a polluted versus a reference habitat
Authors: Zhou Tong , John-Alder Henry B , Weis Peddrick , Weis Judith S
Published: March 2010

Previous studies have demonstrated that mummichogs (Fundulus heteroclitus) collected from Piles Creek (PC), New Jersey, USA (a site polluted with heavy metals and organic materials), were sluggish and showed poorer prey capture and predator avoidance than those from a reference site (Tuckerton [TK], NJ, USA). We hypothesized that the behavioral dysfunction of the PC fish might be associated with thyroid impairment due to toxic exposures. In this preliminary study, we compared thyroid histology and thyroid hormones in the two populations and experimentally determined whether a polluted or an unpolluted environment could alter levels of thyroid hormones. In comparison to TK, PC fish had larger thyroid follicles and greater follicle epithelial cell heights and also contained significantly higher plasma thyroxine (T4) levels. However, no significant differences were found in levels of either plasma or tissue triiodothyronine (T3). The TK fish raised in a simulated PC environment contained higher plasma T4 and lower plasma T3 levels than those sampled from the field. The PC fish raised in clean water showed a reduction in both plasma T4 and T3 levels in comparison to field-sampled fish. In either case, no significant difference was found in tissue T3 content. The contaminants in PC may cause the differences in thyroid structure and function, which may be partly responsible for the behavioral differences between fish from the polluted PC and from the reference TK.
Effects of the agricultural pesticides atrazine, deethylatrazine, endosulfan, and chlorpyrifos on an estuarine microbial food web
Authors: DeLorenzo Marie E , Scott Geoffrey I , Ross Philippe E
Published: March 2010

Aricultural pesticide runoff is a critical issue for many southeasternestuaries. The estuarine microbial food web plays an important role in nutrient cycling and transfer of nutrients to higher trophic levels. The present study examined the effects of agricultural pesticides on the estuarine microbial food web. Polyurethane foam substrates were used to collect microbial communities from a reference tidal creek in the North Inlet National Estuarine Research Reserve (Georgetown, SC, USA). Colonized substrates were brought into the laboratory and exposed to the following commonly used agricultural pesticides: atrazine (and a metabolite, deethylatrazine), endosulfan, and chlorpyrifos. Chlorophyll a, phototrophic carbon assimilation, dissolved oxygen, and phototrophic biovolume were significantly reduced at concentrations of 50 and 250 μg/L atrazine and deethylatrazine. Generally, inhibition of the phytoplankton resulted in increased bacterial abundance and productivity, whereas heterotrophic ciliate and flagellate abundances were not affected. Total bacterial abundance, but not heterotrophic bacterial productivity, was significantly reduced with endosulfan treatments of 1 and 10 μg/L. Endosulfan was primarily found to target the cyanobacteria. Changes in biomass reflected compositional shifts in the phototrophs. The abundance of heterotrophic ciliates and flagellates was significantly reduced at 10 μg/L chlorpyrifos. Bacterial abundance and productivity increased, whereas phototrophic variables decreased. Agricultural pesticides were found to alter both functional and structural aspects of the estuarine microbial food web.
Genetic and demographic responses of mosquitofish (Gambusia holbrooki) populations exposed to mercury for multiple generations
Authors: Tatara Christopher Paul , Mulvey Margaret , Newman Michael C
Published: March 2010

Genetic and demographic responses of mosquitofish were examined after multiple generations of exposure to mercury. Previous studies of acute lethal exposures of mosquitofish to either mercury or arsenic demonstrated a consistent correlation between time to death and genotype at the glucosephosphate isomerase-2 (Gpi-2) locus. A mesocosm study involving mosquitofish populations exposed to mercury for 111 d showed significant female sexual selection and fecundity selection at the Gpi-2 locus. Here the mesocosm study was extended to populations exposed to mercury for several (approx. four) generations. After 2 years, control and mercury-exposed populations met Hardy–Weinberg expectations and showed no evidence of genetic bottlenecks. The mean number of heterozygous loci did not differ significantly between the mercury-exposed and control populations. Significant differences in allele frequencies at the Gpi-2 locus were observed between the mercury-exposed and control populations. Relative to the initial and control allele frequencies, the Gpi-2100 allele frequency was lower, the Gpi-266 allele frequency increased, but the Gpi-238 allele frequency did not change in mercury-exposed populations. No significant differences were found in standard length, weight, sex ratio, or age class ratio between the control and mercury-exposed populations. Allele frequency changes at the Gpi-2 locus suggest population-level response to chronic mercury exposure. Changes in allele frequency may be useful as indicators of population response to contaminants, provided that the population in question is well understood.
Use of rainbow trout primary epidermal cell cultures as an alternative to immortalized cell lines in toxicity assessment: A study with nonoxynol
Authors: Dowling Kevin , Mothersill Carmel
Published: March 2010

Increased concern has centered around environmental contaminants that exert estrogenic effects. A class of nonionic surfactants, the nonylphenol ethoxylates (such as the compound nonoxynol), are an example of one such group of contaminants. We studied the effects of nonoxynol (α-(4-nonylphenyl)-ω-hydroxypoly-(oxy-1-ethanediyl)) on an epithelial primary culture. The culture system that was employed is a development of an in vitro technique for the culture of rainbow trout (Onchorynchus mykiss) epithelium, one that allows for the culture of both epithelial cells and goblet cells. The LC50 after 24 h was found to be 16.6 μmol/L. The LC50 after 48 h was 12.9 μmol/L. Nonoxynol was found to exhibit an acute lethal dose of 75 μmol/L. A decrease in the number of goblet cells present in the system was observed as exposure to nonoxynol increased. Nonoxynol was found to kill epithelial cells mainly by necrosis. A comparative study of the effects of nonoxynol on the epithelium papulosum cyprini cell line was also carried out. The LC50 of nonoxynol on this cell type was 4.1 μmol/L, with an acute lethal dose of 10 μmol/L.
Effects of a pulsed treatment with the herbicide afalon (active ingredient linuron) on macrophyte-dominated mesocosms. II. Structural responses
Authors: Van Geest Gerben J , Zwaardemaker Nathalie G , Van Wijngaarden René PA , Cuppen Jan GM
Published: March 2010

Outdoor mesocosms (experimental drainage ditches) were treated repeatedly with linuron at nominal concentrations of 0, 0.5, 5, 15, and 50 μg/L. After each of three treatments (with 4-week intervals), the systems were kept static for 1 week. Subsequently, they were flushed with nonpolluted surface water with a residence time of 5 d until the next treatment. Species composition and abundance of macrophytes, periphyton, phytoplankton, zooplankton, and macroinvertebrates were examined at prefixed time intervals. During the treatment periods, significant decreases in oxygen concentration and pH were observed, whereas the systems recovered during the flushing periods. The effects of the pulsed treatments on the structural endpoints (biota) were rarely significant and consistently were difficult to interpret. We conclude that under these experimental conditions, pulsed treatment with linuron causes only minor and negligible effects on the abundance of organisms in mesocosms, even when maximum permissible concentrations are exceeded by about 80 times. Risk assessment based on the more sensitive physiologic and functional endpoints suggested that the safety factor of 0.1 times the acute EC50 of the most sensitive standard alga (Scenedesmus acutus), as adopted in the Uniform Principles of the European Union, is sufficient to protect the community of the mesocosms in an exposure regime that was realistic for Dutch drainage ditches, using a photosynthesis inhibitor as the benchmark compound.
An evaluation of the seven-day toxicity test withAmericamysis bahia(formerlyMysidopsis bahia)
Authors: Lussier Suzanne M , Kuhn Anne , Comeleo Randy
Published: March 2010

The7-d test measuring survival, growth, and fecundity of Americamysis bahia (formerly Mysidopsis bahia) was developed for estimating the chronic toxicity of effluents and associated receiving waters for National Pollutant Discharge Elimination System permits. Currently, this test and its derivatives are also used in toxicity identification evaluation (TIE), risk assessment, and other applications. To evaluate the relative sensitivity of three measurement endpoints (survival, growth, and fecundity), we analyzed results from 115 tests with effluents, organic or inorganic chemicals, and receiving waters suspected of being toxic. Controls for 78 of these (68%) achieved acceptable survival and growth. Fifty of these 78 tests (64%, i.e., 43% of the total tests) also achieved acceptable control fecundity. In the 47 tests with significant effects, survival was the most sensitive response in 57%, fecundity in 30%, and growth in 30%. There was little duplication in responses. Improving pretest holding conditions by decreasing the maximum density from ∼20 to 10 animals/L and increasing the temperature from ∼26°C to a range of 26 to 27°C improved the growth and fecundity in controls. Although the percentage of tests achieving acceptable control survival (>80%) and growth (>0.20 mg) decreased from 93 to 86%, the percentage achieving acceptable fecundity in controls (>50%) increased from 60 to 97%. Seasonal differences in fecundity were detected among control groups. Although variable, fecundity is often the most sensitive measure of response. The 7-d mysid test estimates the chronic toxicity of effluents most effectively when all three endpoints are used.
Determination of the sensitivity of macroinvertebrates in stream mesocosms through field-derived assessments
Authors: Dyer Scott D , Belanger Scott E
Published: March 2010

The extrapolation of no observed effect concentrations derived from experimental ecosystem tests (mesocosms) to the field assumes low assessment factors, i.e., the test system is sensitive and serves as a good surrogate for the field. We tested this assumption by comparing the responses of dominant invertebrate taxa exposed to municipal effluent in Procter&Gamble's experimental stream facility (ESF) to those of the same taxa found in routine field samples collected by the Ohio Environmental Protection Agency (1,112 sites). The index of community sensitivity was used as the basis for comparison of mesocosm responses to field-collection data. Control ESF responses corresponded to the 75th and 80th percentiles, whereas most effluent responses corresponded to between the 22nd and 30th percentiles. These analyses support the use of a low assessment factor for the ESF.
Growth and fertility ofCaenorhabditis elegans(nematoda) in unpolluted freshwater sediments: Response to particle size distribution and organic content
Authors: Höss Sebastian , Haitzer Markus , Traunspurger Walter , Steinberg Christian EW
Published: March 2010

The nematode Caenorhabditis elegans (Maupas) was exposed in a sediment bioassay to 26 different unpolluted freshwater sediments varying in particle size distribution (2.5–18% clay, 25.7–68.2% silt, 18.7–70.9% sand) and organic content (2.5–77.1%). We examined the variation of the test endpoints body length, eggs per worm, and percentage of gravid worms. Caenorhabditis elegans tolerated all investigated sediments, with at least 80% (total mean 96.6%) of the worms reaching the stage of reproductive adults. Variation in body length was small (total mean 1,235 ± 97.8 μm), but significant differences among the various sediments were found. We found a weak correlation of body length with particle size distribution, indicating that the nematodes grew better in coarser sediments. The number of eggs per worm showed relatively high variation among treatments (total mean 12.4 ± 4.8) and also within treatments (mean ± 5–95%). C. elegans is a suitable test organism for freshwater sediment bioassays, using body length and percentage of gravid worms as test endpoints.
Whole effluent toxicity testing—usefulness, level of protection, and risk assessment
Authors: Chapman Peter M
Published: March 2010

The general status of whole effluent toxicity (WET) tests is assessed relative to their generally accepted purpose of identifying, characterizing, and eliminating toxic effects of effluents on aquatic resources. Although WET tests are useful, they are not perfect tools (no perfect tools exist). Imperfections include the innate variability of these tests, due both to biotic and anthropogenic factors; the reality of species differences both between the laboratory and the field and within the field; and differences between the laboratory and the receiving environment. Whole effluent toxicity tests may be overprotective (because of their conservative nature, the absence of environmental and ecological processes that could ameliorate exposure, and sensitivity to noncontaminant effects), underprotective (because the most sensitive species cannot be tested, multiple stresses tend to be present in the receiving environment, and failure to account for food chain effects or all possible endpoints), or offer an uncertain level of protection (intermittent doses and mixtures in the environment, adaptations, and hormesis). The implication of hormesis and inverted U-shaped dose responses for WET testing are reviewed in particular detail. Comparisons to field conditions indicate that WET tests are not reliable predictors of effects or lack of effects in the receiving environment. Whole effluent toxicity tests are only the first stage in a risk assessment and as such identify hazard, not risk. Identification of risk requires discarding the concept of independent applicability. The appropriate use of WET tests is identified in the context of their advantages and disadvantages.
Applications and statistical properties of minimum significant difference-based criterion testing in a toxicity testing program
Authors: Wang Qin , Denton Debra L , Shukla Rakesh
Published: March 2010

As a follow up to the recommendations of the September 1995 SETAC Pellston Workshop on Whole Effluent Toxicity (WET) on test methods and appropriate endpoints, this paper will discuss the applications and statistical properties of using a statistical criterion of minimum significant difference (MSD). We examined the upper limits of acceptable MSDs as acceptance criterion in the case of normally distributed data. The implications of this approach are examined in terms of false negative rate as well as false positive rate. Results indicated that the proposed approach has reasonable statistical properties. Reproductive data from short-term chronic WET test with Ceriodaphnia dubia tests were used to demonstrate the applications of the proposed approach. The data were collected by the North Carolina Department of Environment, Health, and Natural Resources (Raleigh, NC, USA) as part of their National Pollutant Discharge Elimination System program.
Treated wastewater as a source of sediment contamination in gulf of Mexico near-coastal areas: A survey
Authors: Lewis Michael , Weber David , Stanley Roman , Albrecht Barbara
Published: March 2010

The primary objective of this baseline survey was to provide some needed perspective on the magnitude of sediment contamination associated with wastewater outfalls discharged to Gulf of Mexico near-coastal areas. The chemical quality and toxicities of whole sediments and pore waters collected from three coastal rivers and four coastal bays receiving wastewaters were assessed during a 2-year period. Rooted plants, invertebrates, and fish were used to assess the acute and chronic toxicities of sediments associated with a total of 10 industrial, municipal, steam electric-power generation and forest product wastewater outfalls. Effects on bacterial bioluminescence, early seedling biomass, survival, reproduction, fertility, and growth were determined in bioassays ranging from 30 min to 28 d duration. Sediment chemical contamination was localized and decreased with increasing distance from the discharge areas. The major sediment contaminants, with few exceptions, were divalent trace metals, which increased, on average, by 69% below 8 of the 10 outfalls. However, only a few concentrations exceeded proposed threshold sediment quality assessment guidelines. Toxicity to either the plant or animal test species was observed occasionally below 7 of the 10 outfalls, but its detection was dependent on the type of bioassay and the frequency of use. Consequently, a suite of bioassays conducted on multiple occasions appears to be needed for toxicity assessments of sediments collected below wastewater discharges in the Gulf region to ensure relevancy of the results. This is particularly true for low to moderately contaminated sediments where acute toxicity is uncommon, which was the case in this study.
Environmental fate of nonylphenol ethoxylates: Differential adsorption of homologs to components of river sediment
Authors: John Dominic M , House W Alan , White Graham F
Published: March 2010

Nonylphenol ethoxylate (NPEOx) homologs present in commercial mixtures were rapidly adsorbed to and desorbed from native river sediment. Adsorption isotherms, established using high-performance liquid chromatography analysis to monitor individual homologs NPEO3 to NPEO13 simultaneously, were linear for each component adsorbing to native sediment, organic-free sediment, and kaolinite, usually with small positive intercepts on the isotherms indicating an additional low-capacity, high-affinity binding site. The adsorption partition coefficients (Kd) for the native sediment decreased progressively from 1,460 L/kg for NPEO3 to 450 L/kg for NPEO10, then increased again slightly for higher homologs. In contrast, Kd values for organic-free sediment (range 230–590 L/kg) or kaolinite (190–490 L/kg) increased steadily from NPEO3 to NPEO13. Adsorptions to silica and alumina were very weak, but to sewage sludge all components adsorbed strongly (Kd values 12,000–33,000, with a maximum at NPEO7). The adsorption to sewage sludge was related to the low-capacity, high-affinity sites observed for native sediment. Dependence of Kd values on ethoxylate chain length was analyzed, in terms of both possible adsorption mechanisms, and the environmental fate and impact of NPEOxs as endocrine disruptors.
Estrogenicity of benzophenones evaluated with a recombinant yeast assay: Comparison of experimental and rules-based predicted activity
Authors: Schultz T Wayne , Seward Julie R , Sinks Glendon D
Published: March 2010

In a previous study, structure-based rules were formulated to predict estrogenicity of phenolic molecules. The determination of estrogenic activity (EC50) and acute toxicity (LC50) of benzophenones was undertaken, and experimental and predicted estrogenic potency values were compared. The Saccharomyces cerevisiae-based lac-Z reporter assay was used to generate experimental data. Estrogenicity was measured colormetrically as β-galactosidase activity. On the basis of the series of rules, β-galac-tosidase activity was predicted correctly for 14 of the 18 benzophenones tested. As predicted, benzophenone, as well as derivatives with a methyl-, chloro-, or nitro-substituent, exhibited no β-galactosidase activity. As anticipated, 4-hydroxybenzophenone exhibited weak β-galactosidase activity (EC50 value of e-06 M). The 3-hydroxybenzophenone exhibited almost the same activity as the 4-hydroxy derivative, whereas the 2-hydroxy derivative was nonactive. It was observed while replacing the para-hydroxyl group with an amino moiety decreased β-galactosidase activity by a half order of magnitude, replacement of the para-hydroxy moiety with a methoxy group negated activity. The nonsymmetrical trihydroxylated benzophenone exhibited activity near to the monohydrox-yl derivative. Near symmetrical tri- and symmetrical tetrahydroxylated benzophenones were determined to have greater estrogenic activity (EC50 values of e-07 M) than nonsymmetrical molecules. A comparison of estrogenicity (EC50) with acute toxicity (LC50) reveals a less than a 10-fold difference in activities for weaker estrogenic compounds. However, the more hydrophilic, stronger estrogenic compounds typically exhibit a difference of two to three orders of magnitude between EC50 and LC50 values.
Concentrations and dose rate estimates of 134137cesium and 90strontium in small mammals at chornobyl, Ukraine
Authors: Chesser Ronald K. , Sugg Derrick W , Lomakin Michael D , van den Bussche Ronald A , DeWoody J Andrew , Jagoe Charles H , Dallas Cham E , Whicker F Ward , Smith Michael H , Gaschak Sergei P , Chizhevsky Igor V , Lyabik Vitalij V , Buntova Elena G , Holloman Kevin , Baker Robert J
Published: March 2010

Free-ranging mammals near the Chornobyl nuclear reactor are experiencing substantial radiation dose rates from intramuscular concentrations of 134137Cs and skeletal 90Sr. Radiocesium concentrations averaged 3,200 Bq/g of dry muscle, compared to a mean of 297 Bq 90Sr/g in bone for mammals in the Exclusion Zone, a region of restricted human activity surrounding the reactor. Estimates of dose rates from intramuscular sources of radiocesium averaged 2.4 mGy/d within 8 km of the reactor and ranged as high as 60 mGy/d. Overall dose rates from internal 90Sr for mammals in the Exclusion Zone averaged 1.0 mGy/d, although doses to specific tissues are likely much higher. Mammals captured 30 km southeast of the reactor averaged only 2 Bq/g of muscle and were receiving an average of 1.4 μuGy/d from internal radiocesium. Dramatic variation exists in the spatial pattern of radiocesium in areas immediately surrounding the reactor and within and between remediated and unremediated regions. The variance of 90Sr for taxa among sites was significantly less than that for 134137Cs. Thermoluminescent dosimeters placed on free-ranging mice showed that dose rates from external sources of radiation were much greater than the dose rates from internal sources of radiocesium. Estimated dose rates in very small areas of the Chornobyl region exceed those reported to impede reproductive success in mammals.
Polychlorinated dioxins and furans in sediments at a site colonized byDreissenain western lake Ontario, Canada
Authors: Marvin Christopher H , Howell E Todd , Reiner Eric J
Published: March 2010

Potential impacts of Dreissena on polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in sediment were investigated by comparing PCDD/PCDF levels in colonized sediment with levels in sediment in the same area that was not colonized but that was exposed to similar environmental conditions. Levels of PCDDs/PCDFs were also determined in Dreissena tissues. The particle size distribution of colonized sediment was characterized by silt-size material with peak abundance in the range of 7.5 to 20 μm, whereas noncolonized sediment was coarser in nature (30–60 μm). Total organic carbon (TOC) and concentrations of the PCDD/PCDF congener groups and individual 2,3,7,8-substituted isomers were greater in colonized sediment. A trend was observed toward decreasing concentrations of PCDF congener groups with increased chlorine substitution in mussel tissues in contrast to increasing concentrations of PCDF congener groups with increased chlorination in sediments. The trend in the PCDD congener group profile in mussel tissues appeared more similar to the profile in sediments. Areal estimates of toxicity equivalents (TEQ) in Dreissena biomass at Port Dalhousie, Ontario, Canada (approx. 1,300 pg/m2) were about 0.9% of the TEQ in the top 3 cm of sediment (approx. 135,000 pg/m2). Differences in particle size distribution and PCDD/PCDF levels between colonized and noncolonized sediment suggest that Dreissena may influence chemical and physical properties of sediment they colonize.
USE of outdoor freshwater pond microcosms: I. Microcosm design and fate of pyridaben
Authors: Rand Gary M , Clark James R , Holmes Catherine M
Published: March 2010

An outdoor freshwater microcosm study was conducted in which pyridaben, an insecticide-miticide, was directly applied to water to determine its fate and biological effects on an aquatic community. The following paper describes the design, specific techniques, and fate of pyridaben in microcosms including model prediction of the estimated environmental concentration, whereas the subsequent paper describes the responses of biota. An analysis of variance design was used with four treatments in which pyridaben was applied as an aqueous suspension (75% wettable powder) at three concentrations (0.34, 3.4, 34.0 μg/L) plus an untreated control to 24 microcosm tanks (23 m3). Each treatment was replicated six times. Pyridaben was applied to each microcosm once in April and once in May 1993 to simulate actual crop application. The Exposure Analysis Modeling System predicted that as a result of a drift (5.0%) exposure scenario, the half-life of pyridaben in water was 30 to 34 h. The model also predicted negligible concentrations of pyridaben in sediment after drift. Surface runoff was not considered an important source of pyridaben to aquatic systems, because the Pesticide Root Zone Model predicted a maximum runoff concentration of 0.1 μg/L. The half-life in microcosm water for the low, middle, and high treatment concentrations for both applications ranged from 11.8 to 28.5 h. After both applications at 3.4 μg/L, pyridaben was not detected in sediment within 24 h, whereas at 34.0 μg/L the half-life of pyridaben in sediment was 9.8 d.
Comparative study of toxicity testing and macroinvertebrate assessment of petroleum storage and manufacturing site and receiving water
Authors: T. Vernon Beaty  , McFee Wayne E , Flemming Charmaine A , Giffin Mark
Published: March 2010

Toxicity tests were performed on runoff associated with manufacturing activity and effluent from chemical and petroleum storage tank containment areas. Toxicity tests and macroinvertebrate surveys were used to assess the quality of receiving streams. The sensitivity of Ceriodaphnia dubia and Brachionus calyciflorus to these effluents was compared. The 95% confidence limits of the probit LC20 (concentration inversely predicted to kill 20% of test organisms), probit E100 (effect predicted by the probit model at 100% effluent), and linear E100 (effect predicted by a first-order binomial model at 100% effluent) were used as toxicity criteria and compared, and the results of effluent and receiving water toxicity tests and macroinvertebrate assessments were compared. B. calyciflorus was unaffected by effluents that were toxic to C. dubia. The toxicity criteria generally agreed, but most disagreements involved LC20s with infinite inverse confidence limits, a problem that made the LC20 impractical. Even though discharges were frequently toxic, few downstream samples were toxic, and macroinvertebrate assessments failed to detect impact at most stations. Sensitivity of macroinvertebrate assessments was adversely affected by land development around the study sites. The macroinver-tebrate indices were difficult to interpret because their variances were not known.
USE of cholinesterase in aporrectodea caliginosa (Oligochaeta; Lumbricidae) to detect organophosphate contamination: Comparison of laboratory tests, mesocosms, and field studies
Authors: Booth Lynn H , Hodge Simon , O'Halloran Kathryn
Published: March 2010

Acute and sublethal enzyme responses were assessed in the earthworm Aporrectodea caliginosa (Savigny) exposed to chlorpyrifos and diazinon in the laboratory, mesocosms, and field exposures. The aim of this work was to evaluate whether cholinesterase (ChE) activity has potential as a biomarker of organophosphate exposure in earthworms. No mortality or population changes were found at the recommended field application rates of the pesticides in the three experimental systems. Cholinesterase activity was severely inhibited in earthworms exposed to sublethal doses in laboratory tests. However, no effects of the pesticides on ChE were found in the mesocosm or natural worm populations.
Temporal trends in ethoxyresorufin-o-deethylase activity of brook trout (Salvelinus fontinalis) fed 2,3,7,8-tetrachlorodibenzo-p-dioxin
Authors: Cormier Susan M , Millward Michael R , Mueller Cornelia , Subramanian Bhagya , Johnson Rodney D , Tietge Joseph E
Published: March 2010

Changes in ethoxyresorufin- O-deethylase (EROD) activity were monitored through an extended 6-month dietary exposure to determine the relationship between EROD activity and uptake of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in brook trout, Salvelinus fontinalis. Brook trout were fed labeled TCDD during a 4-week loading phase and an 11-week maintenance phase to achieve whole-body concentrations of 0, 75, 150, 300, 600, and 1,200 pg TCDD/g fish. A spawning phase followed during which no TCDD was introduced. The TCDD had an extended half-life, with maximal levels detected in the late loading-early maintenance phases and 81 d after TCDD had been removed from the diet. Accumulation in liver increased as whole-body target concentration increased but was generally less than half of anticipated whole-body target concentrations. The EROD activity demonstrated a dose-dependent increase. Positive correlations were observed between EROD activity and TCDD body burdens for both males and females. For males, maximal induction was attained early in the maintenance phase and maintained during latter phases. For females, induction was characterized by a biphasic pattern. Maximal induction was attained during late loading-early maintenance, with an attenuated response observed just before spawning. In addition, the induction response was modulated by sex, as induction was lower in females when compared with males. If sexual biases are considered, increased EROD activity may serve as an indicator of level of TCDD exposure and a sublethal predictor of effects of exposure.
Behavior of trace metals in the sediment pore waters of intertidal mudflats of a tropical wetland
Authors: Yu Kai-Tung , Lam Michael Hon-wah , Yen Yu-Fong , Leung Amy PK
Published: March 2010

Vrtical profiles ofdissolvedCd, Cr, Cu, Pb, Zn, Fe, and Mn in the sediment pore waters of the intertidal mudflats of the Mai Po and Inner Deep Bay Ramsar Site of Hong Kong, People's Republic of China, were measured using the polyacrylamide gel diffusive equilibration thin film (DET) technique. The ranges of concentrations of dissolved Cd, Cr, Cu, Pb, Zn, Fe, and Mn in the pore water of the top 0 to 20 cm of sediment were 2.2 to 10.0 nM, 346.0 to 950.0 nM 243.8 to 454.8 nM, 23.2 to 51.2 nM, 39.8 to 249.5 μM, and 13.4 to 20.7 μM, respectively. Enrichment of these trace metals was observed in the upper 0- to 7-cm layer. Profiles of conditional distribution coefficient, log(KD), of the trace metals and results of multiple regression analysis have revealed that reduction of Mn (hydrous) oxides was the major remobilization mechanism for Cd, Cr, Cu, Pb, and Zn in the mudflats. Benthic diffusive fluxes of these trace metals from the mudflats were also estimated on the basis of the concentration gradients of trace metals between surface sediments and the overlying water column. The magnitude of the estimated diffusive fluxes followed the order Zn > Cr > Cu > Pb > Cd.
Impact of storm-water outfalls on sediment quallity in corpus Christi Bay, Texas, USA
Authors: Carr R Scott , Montagna Paul A , Biedenbach James M , Kalke Rick , Kennicutt Mahlon C , Hooten Russell , Cripe Geraldine
Published: March 2010

To determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm-water outfalls, but 13 other sites (i.e., industrial and domestic outfalls, oil field–produced water discharges, and dredging activity) and eight reference sites were also evaluated. Sediment samples were collected and analyzed for physical–chemical characteristics, contaminant concentrations (metals, polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and pesticides), toxicity (amphipod and mysid solid phase and sea urchin pore-water fertilization and embryological development tests), and a benthic index of biotic integrity (BIBI) composed of 10 independent metrics calculated for each site. This large data matrix was reduced using multivariate analysis to create new variables for each component representing overall means and containing most of the variance in the larger data set. The new variables were used to conduct the correlation analysis. Toxicity was significantly correlated with both chemistry and ecological responses, whereas no correlations between the benthic metrics and sediment chemistry were observed. Using the combined information from the SQT, four of the five most degraded sites were storm-water outfall sites. Although estuaries are naturally stressful environments because of salinity and temperature fluctuations, this ecosystem appears to have been compromised by anthropogenic influences similar to what has been observed for other heavily urbanized bay systems along the Texas and Gulf coast.