bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate of adsorbable organic halides from bleached laundering in septic tank systems
Authors: Braida Washington , Ong Say Kee , Smith William L , McCabe James W 
Published: March 2010

Abstract
A study was conducted to assess the fate of adsorbable organic halide (AOX) formed from the use of household bleach during laundering in a septic system. Experiments were conducted using laboratory-scale septic tanks and leachfield systems. Addition of feed water containing 20% of bleached or unbleached laundry wash water did not affect the performance of the septic tanks or the leach fields. Overall chemical oxidation demand (COD) and total organic carbon (TOC) removal rates through the septic systems were in the range of 90%. Adsorbable organic halide from unbleached laundry wash water with concentrations between 0.13 and 0.21 mg/L appeared to be removed in the septic tank but not in the leach field. The average overall AOX removal rate using unbleached laundry wash water was approx. 43%. In contrast, the overall removal rate of AOX generated from the use of sodium hypochlorite in bleached laundry wash water was between 87 and 94%. About one-third of the AOX was removed in the septic tank, and the rest was removed in the leach field. Analysis of the septic tank sludge and the soil in the leach field showed no accumulation of AOX from the use of hypochlorite, and the AOX was most likely removed by biodegradation and/or chemical degradation.
Using a spiked sediment bioassay to establish a no-effect concentration for dioxin exposure to the amphipodAmpelisca abdita
Authors: Barber Timothy R , Chappie Daniel J , Duda Deborah J , Fuchsman Phyllis C , Finley Brent L 
Published: March 2010

AbstractA recent study conducted by the National Oceanic and Atmospheric Administration (NOAA) reported a highly significant correlation between 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) concentrations and amphipod (Ampelisca abdita) mortality in sediment samples collected from the lower Passaic River and Newark Bay. However, there is a paucity of data regarding the potential effects of 2,3,7,8-TCDD on benthic invertebrates under controlled laboratory exposures. In this study, 10-d whole-sediment bioassays using the marine amphipod A. abdita were conducted on spiked sediment samples representing a range of 2,3,7,8-TCDD concentrations (0–25 μg/kg dry weight). No effects on survival or growth relative to controls were observed at any test concentration. The highest 2,3,7,8-TCDD concentration reported from the NOAA study was 0.62 μg/kg. Therefore, the lack of 2,3,7,8-TCDD toxicity in this study indicates that the mortality observed in the NOAA study was probably due to factors or chemicals other than 2,3,7,8-TCDD. This study demonstrates the utility of spiked sediment bioassays in evaluating cause and effect relationships between sediment contamination and benthic invertebrate mortality.
Algal growth rate fluctuations observed under uniform ambient test conditions using static and semicontinuous assay techniques
Authors: Benjamin Richard B , Brown Ray , Fraizer Merideth , Joab Bruce M , Casey Ryan E , Klaine Stephen J 
Published: March 2010

Abstract
A simple, manually diluted, semicontinuous, 96-h algal growth assay technique was developed to measure changing rates of population growth following sublethal chemical exposure. Rates were estimated directly from changing cell counts in a fixed volume of cell suspension. Short-term rate fluctuations in exponential rate parameters were observed in Selenastrum capricornutum populations using this method and similar fluctuations were also documented by reanalyzing conventional static culture assay data. Replicate cultures tended to fluctuate in unison, and patterns of population increase were similar in static assays initiated on different dates. The latter suggested that nonuniform rates of S. capricornutum population increase were not due simply to environmental variation. All populations were preacclimated to test conditions, but growth lags were consistently observed for 12–24 h following inoculation. Subsequent rate fluctuations probably resulted from a high degree of cell-cycle synchronization. Treating systematic rate fluctuations as random error lowered measurement precision, especially with respect to estimates of rate changes over time. Systematic variance may be difficult to eliminate in practice, but repeated-measures regression methods can account for this effect and substantially reduce rate parameter confidence intervals. Findings are expected to apply to endpoints such as dry weight, total cell volume, chlorophyll, or DNA.
Availability of sludge-borne silver to agricultural crops
Authors: Hirsch Marianne P 
Published: March 2010

Abstract
Three green house studies were conducted to evaluate the availability of sludge-borne silver to a variety of agricultural crops. Two studies utilized anaerobically digested domestic sewage sludge that had been amended with silver sulfide in the laboratory prior to mixing the sludge with a screened topsoil. A third study utilized an aerobically digested, laboratory-prepared sludge synthesized by feeding sludge microorganisms a representative solution from a standard photoprocessing operation. The synthetic sludge was also mixed with screened topsoil. There were no differences in the mean number of days to emergence or percent emergence of seedlings grown in sludge-amended soils containing silver sulfide or seedlings grown in soils amended with silver-laden, waste-activated sludge. The growth and yields of corn, oat, and turnip plants were not affected by the presence of silver sulfide in sludge-amended soils at concentrations as high as 106 mg Ag/kg soil. The dry weights of Chinese cabbage plants grown in the sludge-amended soils containing silver sulfide at concentrations of ≥14 mg Ag/kg were significantly less than the controls. The presence of silver sulfide in the sludge-amended soils did not remove the beneficial effects of adding sludge to the soil as plant growth was greater in sludge-amended soils than in soil alone. The yields of lettuce, oat, turnip, and soybean plants grown in soils amended with the laboratory-prepared, silver-laden, waste-activated sludge were significantly greater than those of the controls. At maturity, selected tissues of each species were analyzed for silver. With the exception of lettuce, there were no significant differences in the silver concentrations of the edible tissues of the crops grown in soils containing silver sulfide when compared with controls. The results of these studies indicate that sludge-amended soils containing silver sulfide are not likely to affect adversely the growth of crops, and accumulation of low levels of silver may occur in the leaves of lettuce plants grown in soils containing silver.
Exposure of female juvenile rainbow trout to alkylphenolic compounds results in modifications to growth and ovosomatic index
Authors: Ashfield Lindsey A , Pottinger Tom G , Sumpter John P 
Published: March 2010

Abstract
The alkylphenol ethoxylates (APEOs) are a major group of nonionic surfactants. Biodegradation of these compounds is incomplete during sewage treatment; thus, they are ubiquitous aquatic pollutants. All the main degradation products of APEOs were recently demonstrated to have estrogenic properties in vitro, but their effects in vivo remain to be established. In this study, female juvenile rainbow trout (Oncorhynchus mykiss Walbaum) were exposed to octylphenol, nonylphenol (NP), nonylphenol diethoxylate, and nonylphenol mono-carboxylic acid (NP1EC) at environmentally relevant concentrations (Experiment 1: 1, 10, and 50 μg/L; Experiment 2: 1, 10, and 30 μg/L). Exposure to APEOs commenced at hatch (day 0) and was terminated on day 22 (Experiment 1) or day 35 (Experiment 2). Body weight and fork length of representative samples offish from each treatment group were recorded at intervals up to 108 d (Experiment 1) or 466 d (Experiment 2). In Experiment 1, significant differences in size of the exposed fish, related to treatment, were still apparent on day 108, 86 d after withdrawal of the treatments. These observations were confirmed during Experiment 2, in which significant changes in body weight and fork length as a consequence of exposure to the compounds were observed approx. 15 d after exposure was terminated. These differences were sustained for at least 466 d in the case of NP and NP1EC. In addition, the ovosomatic index (OSI) offish exposed to NP and NP1EC was significantly affected zby the treatment. Survival of fish in the natural environment is strongly influenced by body size, and an appropriate OSI is a crucial factor in successful reproduction. Therefore, exposure of natural populations of fish to these chemicals at concentrations currently measurable in the aquatic environment may have an impact on the performance of those populations.
Reduction of aryl hydrocarbon receptor-mediated activity of polychlorinated biphenyl mixtures due to anaerobic microbial dechlorination
Authors: Quensen John F , Mousa Mahmoud A , Boyd Stephen A , Sanderson J Thomas , Froese Kenneth L , Giesy John P 
Published: March 2010

Abstract
Aroclors 1242 and 1254 were anaerobically dechlorinated by microorganisms eluted from polychlorinated biphenyl (PCB)-contaminated River Raisin (RR) and Silver Lake (SL) sediments. Dechlorination occurred primarily from the meta positions. H4IIE rat hepatoma cell bioassays for ethoxyresorufin-O-deethylase (EROD) induction potency, a measure of aryl hydrocarbon receptor-mediated toxic potential, revealed that the potencies of the Aroclors were considerably reduced after dechlorination. The decreases in EROD induction potencies were dependent on the extent of dechlorination of the non-ortho-substituted and mono-ortho-substituted PCBs. Calculated 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEqscalc) for the PCB mixtures were 5.7, 0.08, and 0.05 pM TEqcalc/μmole of PCBs for non-, RR-, and SL-dechlorinated Aroclor 1242, and 7.8, 1.6, and 1.0 pM TEqcalc/μmole of PCBs for non-, RR-, and SL-dechlorinated Aroclor 1254, respectively. Correspondence between TEqsassay determined using the H4IIE bioassay and TEqscalc indicated that no unexpected synergistic interactions occurred among components of the dechlorinated mixtures. These results indicate that the dioxinlike toxicities of PCB mixtures are substantially reduced by microbial reductive dechlorination, and that a constant ratio of TEq to total PCBs cannot be assumed in risk assessments.
Comparison of marine sediment toxicity test protocols for the amphipodRhepoxynius abroniusand the polychaete wormNereis (Neanthes) arenaceodentata
Authors: Anderson Brian S , Hunt John W , Phillips Bryn M , Tudor Shirley , Fairey Russell , Newman John , Puckett H Max , Stephenson Mark , Long Edward R , Tjeerdema Ronald S 
Published: March 2010

AbstractThe 10-d amphipod survival toxicity test protocol using Rhepoxynius abronius was compared to the 20-d polychaete worm growth and survival protocol using Nereis (Neanthes) arenaceodentata. Of the 341 sediment samples collected in California and tested over a 2-year period, 78% significantly inhibited R. abronius survival, whereas 2 and 26% significantly inhibited N. arenaceodentata survival and biomass, respectively. Statistical power associated with each protocol endpoint was determined by calculating the minimum significant difference (MSD) for each test protocol for this data set. The 90th percentile MSDs for R. abronius survival and N. arenaceodentata survival and biomass were 16, 36, and 56%, respectively. Survival of R. abronius was significantly negatively correlated with a number of toxicants including metals, pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. No significant correlations were determined between N. arenaceodentata survival or biomass and contaminants measured. Amphipod survival was also negatively correlated with sediment total organic carbon and grain size, but when samples with a high percent fine grain size (&gt;90% fines) were eliminated from consideration, the overall conclusions of the study were not altered. The 10-d amphipod survival protocol using R. abronius was a more sensitive indicator of toxicity, but the results indicate that this was due to greater statistical power rather than greater sensitivity of the test organisms or endpoints.
Integrative assessment of sediment quality in two littoral ecosystems from the Gulf of Cádiz, Spain
Authors: DelValls T Ángel , Forja Jesús M , Gómez-Parra Abelardo 
Published: March 2010

AbstractTo evaluate sediment marine environmental quality in the Gulf of Cádiz, an integrative assessment approach was used—the sediment quality triad (SQT). Sediment samples were collected at seven stations in two littoral ecosystems and subjected to six separate, replicated sediment toxicity tests, comprehensive sediment chemistry analyses, and replicated benthic infaunal analyses. Chemistry analyses indicated that different contamination sources were associated with sediments highly contaminated with linear alkylbenzenesulfonates and some heavy metals associated with sewage discharges (Pb, and Ag), sediments with moderate levels of heavy metals associated with industrial activities (Hg, Cr, and As), and other sediments with slight or no contamination. Toxicity tests indicated that sediments close to the sewage discharges were most toxic, those associated with slight or no contamination were not toxic, and those associated with both sewage discharges and industrial sources of contamination were intermediate. Infaunal analyses indicated that communities at the salt-marsh of the Barbate River stations and CB2 station in the Bay of Cádiz were the most altered, whereas those at CB5 and CB3 in the Bay of Cádiz were slightly altered, relative to stations CB1 and CB4 in the Bay of Cádiz. A different methodology to calculate the ratio-to-reference and each composite SQT index value is proposed by adding to the classical normalization by using the reference clean station as a new normalization that includes a reference polluted station to establish a between-the-maximum and minimum level obtained in the area studied. We propose this new methodology to calculate weighted results based on the fact that they are obtained using two points of reference for comparison. The results show that sediment pollution is restricted to the vicinity of one untreated sewage discharge in the Bay of Cádiz.
Uptake and bioconcentration of atrazine by selected freshwater algae
Authors: Tang Jixin , Hoagland Kyle D , Siegfried Blair D 
Published: March 2010

Abstract
Atrazine bioconcentration and uptake were determined for eight freshwater green algae and diatoms. Atrazine uptake was extremely rapid in all species examined, with nearly 90% of total uptake occurring within the first hour of exposure. Within each division, different species had different bioconcentration capacities, although the accumulation of atrazine was consistently higher in green algae (5.43–12.73 ng/mg) than in diatoms (0.33–1.69 ng/mg). Atrazine concentrations in the algal cells were much higher than in the medium, although the total amount of atrazine taken up by algae was small relative to the total atrazine in solution (1–3%). The ability of algal cells to accumulate atrazine was highly correlated with algal cell biovolume and surface area, and a strong relationship was observed between sensitivity to atrazine and bioconcentration, cell biovolume, and surface area. In general, higher bioconcentration factors were associated with increased atrazine sensitivity.
Toxicity of emamectin benzoate to mallard duck and northern bobwhite quail
Authors: Chukwudebe Amechi C , Beavers Joann B , Jaber Mark , Wislocki Peter G 
Published: March 2010

Abstract
Nineteen- to 26-week-old mallard ducks (Anas platyrhynchos) were found to be more sensitive than northern bobwhite quail (Colinus virginianus) of the same age to single oral doses of emamectin benzoate. The resulting median lethal dose values determined for emamectin benzoate to mallard duck and northern bobwhite quail were 76 and 264 mg/kg, respectively, and the no-observed-effect levels were &lt;25 and 25 mg/kg, respectively. Exposure of 10-d-old mallard ducks and bobwhite quail to emamectin benzoate in feed also gave relatively high median lethal concentration (LC50) values of 570 and 1,318 ppm, respectively, and no-observed-effect concentrations of 20 and &lt;125 ppm, respectively. Clinical signs of toxicity included lethargy, ruffled appearance, loss of righting reflex, and reduction in food consumption; these signs appeared to be fully reversible with cessation of exposure. The maximum residue level of emamectin benzoate found in field-treated foliage is several-fold (7,125–16,475) less than these LC50 values. Because the likely primary route of emamectin benzoate exposure to birds is through treated food in the diet, these results indicate minimal acute risk to avians from emamectin benzoate use in crop protection.
Ecological risk assessment of copper and cadmium in surface waters of Chesapeake Bay watershed
Authors: Hall Lenwood W , Scott Mark C , Killen William D 
Published: March 2010

Abstract
This ecological risk assessment was designed to characterize risk of copper and cadmium exposure in the Chesapeake Bay watershed by comparing the probability distributions of environmental exposure concentrations with the probability distributions of species response data determined from laboratory studies. The overlap of these distributions was a measure of risk to aquatic life. Dissolved copper and cadmium exposure data were available from six primary data sources covering 102 stations in 18 basins in the Chesapeake Bay watershed from 1985 through 1996. Highest environmental concentrations of copper (based on 90th percentiles) were reported in the Chesapeake and Delaware (C and D) Canal, Choptank River, Middle River, and Potomac River; the lowest concentrations of copper were reported in the lower and middle mainstem Chesapeake Bay and Nanticoke River. Based on the calculation of 90th percentiles, cadmium concentrations were highest in the C and D Canal, Potomac River, Upper Chesapeake Bay, and West Chesapeake watershed. Lowest environmental concentrations of cadmium were reported in the lower and middle mainstem Chesapeake Bay and Susquehanna River. The ecological effects data used for this risk assessment were derived primarily from acute copper and cadmium laboratory toxicity tests conducted in both fresh water and salt water; chronic data were much more limited. The 10th percentile (concentration protecting 90% of the species) for all species derived from the freshwater acute copper toxicity database was 8.3 μg/L. For acute saltwater copper data, the 10th percentile for all species was 6.3 μg/L copper. The acute 10th percentile for all species in the freshwater cadmium database was 5.1 μg/L cadmium. The acute 10th percentile for all saltwater species was 31.7 μg/L cadmium. Highest potential ecological risk from copper exposures was reported in the C and D Canal area of the northern Chesapeake Bay watershed. Relatively high potential ecological risk from copper exposure was also reported in Middle River. Moderate potential ecological risk from copper exposure was reported in selected locations in the Choptank and Potomac Rivers. Potential ecological risk from copper exposure was either low or data were insufficient to assess ecological risk in the other 14 basins. Potential ecological risk from cadmium exposures was much lower than for copper. Highest potential ecological risk from cadmium exposure was reported in the C and D Canal. Low to moderate potential ecological risk for the most sensitive trophic group (fish) was reported in the Potomac River, upper mainstem bay, West Chesapeake watershed, Choptank River, and Chester River. In the other 12 basins, ecological risk was either judged to be low or insufficient data were available for determining risk.
Tiered aquatic risk refinement: Case study—at-plant applications of granular chlorpyrifos to corn
Authors: Havens Patrick L , Cryer Steven A , Rolston Laurie J 
Published: March 2010

Abstract
The tools of risk assessment are important in the management of environmental risk from the use of agricultural chemicals. A tiered process of estimating and refining the risks from runoff to nontarget aquatic ecosystem is described. The methodology uses screening tools at the lower level of assessment and progresses to a probabilistic, geographically specific tool at the highest tier level. The tools are demonstrated by an analysis of the risks to aquatic ecosystems resulting from the use of granular chlorpyrifos on corn. Vegetative filter strips and reduced tillage were examined as potential best management practices to reduce runoff impact. In addition, data from outdoor microcosm experiments were used to refine toxicity endpoints. The combination of runoff reduction and endpoint refinement resulted in a two- to 16-fold reduction in potential risk, based on 90th percentile endpoints. The results also located where more localized efforts in product stewardship, user education, potential field research, or more refined assessment may be beneficial. The simulation results are compared to field monitoring results.
Response of soil microbial biomass to 1,2-dichlorobenzene addition in the presence of plant residues
Authors: Meharg Andrew A , Wyatt Clare L , Thompson Ian P , Bailey Mark J , Ellis Richard J , Maguire Nicola 
Published: March 2010

Abstract
The impact of 1,2-dichlorobenzene on soil microbial biomass in the presence and absence of fresh plant residues (roots) was investigated by assaying total vital bacterial counts, vital fungal hyphal length, total culturable bacterial counts, and culturable fluorescent pseudomonads. Diversity of the fluorescent pseudomonads was investigated using fatty acid methyl ester (FAME) characterization in conjunction with metabolic profiling of the sampled culturable community (Biolog). Mineralization of [14C]1,2-dichlorobenzene was also assayed. Addition of fresh roots stimulated 1,2-dichlorobenzene mineralization by over 100%, with nearly 20% of the label mineralized in root-amended treatments by the termination of the experiment. Presence of roots also buffered any impacts of 1,2-dichlorobenzene on microbial numbers. In the absence of roots, 1,2-dichlorobenzene greatly stimulated total culturable bacteria and culturable pseudomonads in a concentration-dependent manner. 1,2-Dichlorobenzene, up to concentrations of 50 μg/g soil dry weight had little or no deleterious effects on microbial counts. The phenotypic diversity of the fluorescent pseudomonad population was unaffected by the treatments, even though fluorescent pseudomonad numbers were greatly stimulated by both roots and 1,2-dichlorobenzene. The presence of roots had no detectable impact on the bacterial community composition. No phenotypic shifts in the natural population were required to benefit from the presence of roots and 1,2-dichlorobenzene. The metabolic capacity of the culturable bacterial community was altered in the presence of roots but not in the presence of 1,2-dichlorobenzene. It is argued that the increased microbial biomass and shifts in metabolic capacity of the microbial biomass are responsible for enhanced degradation of 1,2-dichlorobenzene in the presence of decaying plant roots.