25 results on '"Allen M Nielsen"'
Search Results
2. Relationships between benthic macroinvertebrate community structure and geospatial habitat, in-stream water chemistry, and surfactants in the effluent-dominated Trinity River, Texas, USA
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James H. Kennedy, Scott D. Dyer, Bradford B. Price, Allen M. Nielsen, Jaime L. Slye, Kathleen Stanton, Hans Sanderson, Sam F. Atkinson, Michael Ciarlo, and David R. Johnson
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Aquatic Organisms ,Watershed ,Ecology ,Health, Toxicology and Mutagenesis ,Aquatic ecosystem ,Community structure ,Household Products ,Biodiversity ,Invertebrates ,Texas ,Surface-Active Agents ,Rivers ,Habitat ,Benthic zone ,Water Pollution, Chemical ,Animals ,Regression Analysis ,Environmental Chemistry ,Environmental science ,Water quality ,Species richness ,Surface water ,Ecosystem ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
Over the past 20 years, benthic macroinvertebrate community structure studies have been conducted on the upper Trinity River, Texas, USA, which is dominated by municipal wastewater treatment plant (WWTP) and industrial effluents. The Trinity River is located in the Dallas—Fort Worth metropolitan area, and is the most highly populated and industrialized watershed in Texas. As such, the Trinity River represents a near-worst-case scenario to examine the environmental effects of domestic–municipal and industrial effluents on aquatic life. A 1987 to 1988 study concluded that many stretches of the river supported a diverse benthic community structure; however, a decline in taxa richness occurred immediately downstream of WWTPs. A 2005 study designed to parallel the 1987 to 1988 efforts evaluated how changes in water quality, habitat, and increased urbanization impacted benthic community structure. Physicochemical measurements, habitat quality, geospatial variables, and benthic macroinvertebrates were collected from 10 sites. Surfactants were measured and toxic units (TUs) were calculated for surface water and pore water as indicators of domestic/household use of cleaning products. Total TUs indicated a low potential for biological impacts. Toxic unit distribution was not dependent on WWTP location and did not correlate with any benthic variable. Eight environmental parameters were determined to be useful for predicting changes in benthic macroinvertebrate community structure: surfactant surface water TUs (SWTU), in-stream habitat cover, and surface water total organic carbon were the top three parameters. Abundance, taxa richness, and taxa similarity in 2005 had increased since the earlier study throughout the immediate vicinity of the metropolitan area. Environ. Toxicol. Chem. 2011; 30:1127–1138. © 2011 SETAC
- Published
- 2011
3. Human health risk assessment of long chain alcohols
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Scott D. Dyer, Peter R. Fisk, Scott E. Belanger, Richard Sedlak, Gauke Veenstra, Catherine Webb, David Penney, Kathleen Stanton, Yutaka Kasai, Andreas Willing, Hans Certa, Allen M. Nielsen, and Hans Sanderson
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Male ,Skin Absorption ,Health, Toxicology and Mutagenesis ,Administration, Oral ,Quantitative Structure-Activity Relationship ,Biology ,medicine.disease_cause ,Risk Assessment ,Toxicology ,Dogs ,Pregnancy ,medicine ,Animals ,Humans ,Tissue Distribution ,Organism ,Exposure assessment ,Inhalation exposure ,Inhalation Exposure ,Models, Statistical ,Reproduction ,Public Health, Environmental and Occupational Health ,Household Products ,Environmental Exposure ,General Medicine ,Environmental exposure ,Consumer protection ,Pollution ,Rats ,Health ,Toxicity ,Carcinogens ,Irritants ,Female ,Fatty Alcohols ,Irritation ,Risk assessment ,Algorithms ,Mutagens - Abstract
Representative chemicals from the long chain alcohols category have been extensively tested to define their toxicological hazard properties. These chemicals show low acute and repeat dose toxicity with high-dose effects (if any) related to minimal liver toxicity. These chemicals do not show evidence of activity in genetic toxicity tests or to the reproductive system or the developing organism. These chemicals also are not sensitizers. Irritation is dependant on chain length; generally, alcohols in the range C6–C11 are considered as irritant, intermediate chain lengths (C12–C16) alcohols are considered to be mild irritants and chain lengths of C18 and above are considered non-irritants. These chemicals are broadly used across the consumer products industry with highest per person consumer exposures resulting from use in personal care products. Margins of exposure adequate for the protection of human health are documented for the uses of these chemicals.
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- 2009
4. Environmental properties of long chain alcohols. Part 1: Physicochemical, environmental fate and acute aquatic toxicity properties
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Scott D. Dyer, Andreas Willing, Rosalind J. Wildey, Allen M. Nielsen, Peter R. Fisk, Andrew E. Girling, Hans Sanderson, Kathleen Stanton, Gauke Veenstra, Scott E. Belanger, and Yutaka Kasai
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Quantitative structure–activity relationship ,Photochemistry ,Health, Toxicology and Mutagenesis ,Quantitative Structure-Activity Relationship ,Waste Disposal, Fluid ,Aquatic toxicology ,Structure-Activity Relationship ,Animals ,Solubility ,Chemistry ,Public Health, Environmental and Occupational Health ,Water ,General Medicine ,Biodegradation ,Pollution ,Biodegradation, Environmental ,Bioaccumulation ,Environmental chemistry ,Adsorption ,Fatty Alcohols ,Volatilization ,Ecotoxicity ,Long chain ,Water Pollutants, Chemical ,Environmental Monitoring ,Waste disposal - Abstract
This paper summarises the physicochemical, biodegradation and acute aquatic ecotoxicity properties of long chain aliphatic alcohols. Properties of pure compounds are shown to follow somewhat predictable trends, which are amenable to estimation by quantitative structure-activity relationships ((Q)SARs). This allows predictions of data relating to human and environmental safety profiles and patterns. These alcohols have been shown to be rapidly degradable under standard conditions up to C(18). Furthermore, evidence suggests that longer chain lengths are also rapidly biodegradable. While logK(ow) values suggest possible bioaccumulation potential, available data suggest that these substances are not as bioaccumulative as estimations would predict. For acute aquatic toxicity, solubility limits the possibility of effects being appropriately observed and become increasingly challenging above C(12). Further, a model has been developed for multi-component mixtures which give an excellent account of aquatic ecotoxicity allowing for the prediction of acute effects of un-tested mixtures.
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- 2009
5. An overview of hazard and risk assessment of the OECD high production volume chemical category—Long chain alcohols [C6–C22] (LCOH)
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Christoph Schäfers, Allen M. Nielsen, Hans Sanderson, Gauke Veenstra, Kathleen Stanton, Yutaka Kasai, Peter R. Fisk, Scott D. Dyer, Andreas Willing, Scott E. Belanger, Richard Sedlak, and Publica
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High production volume chemicals ,Health, Toxicology and Mutagenesis ,Risk Assessment ,Aquatic toxicology ,Toxicology ,Environmental monitoring ,Animals ,Humans ,Production (economics) ,Mammals ,business.industry ,Public Health, Environmental and Occupational Health ,General Medicine ,Chemical industry ,Environmental economics ,Pollution ,Hazard ,Biodegradation, Environmental ,Daphnia ,Solubility ,Chemical Industry ,Environmental science ,Fatty Alcohols ,Volatilization ,Risk assessment ,business ,Long chain ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
This review summarizes the findings of the assessment report for the category, long chain alcohols (LCOH) with a carbon chain length range of C(6)-C(22) covering 30 substances, and >1.5million tonnes/year consumed globally. The category was evaluated under the Organization for Economic Co-operation and Development (OECD) high production volume chemicals program in 2006. The main findings of the assessment include: (1) no unacceptable human or environmental risks were identified; (2) these materials are rapidly and readily biodegradable; (3) a parabolic relationship was demonstrated between carbon chain length and acute and chronic aquatic toxicity; (4) category-specific (quantitative) structure-activity relationships were developed enabling prediction of properties across the entire category; (5) LCOH occur naturally in the environment in an equilibrium between synthesis and degradation; (6) industry coming together and sharing resources results in minimizing the need for additional animal tests, produces cost savings, and increases scientific quality of the assessment.
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- 2009
6. Contents
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Stephen M Mudge, Scott E Belanger, and Allen M Nielsen
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- 2008
7. Subject Index
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Stephen M Mudge, Scott E Belanger, and Allen M Nielsen
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- 2008
8. Front Matter
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Stephen M Mudge, Scott E Belanger, and Allen M Nielsen
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- 2008
9. Occurrence and weight-of-evidence risk assessment of alkyl sulfates, alkyl ethoxysulfates, and linear alkylbenzene sulfonates (LAS) in river water and sediments
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Bradford B. Price, Remi van Compernolle, Richard Sedlak, Martin Selby, Allen M. Nielsen, Hans Sanderson, Michael Ciarlo, Kathleen Stanton, Alex Evans, and Scott D. Dyer
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Geologic Sediments ,Indiana ,Environmental Engineering ,Quantitative Structure-Activity Relationship ,Sulfuric Acid Esters ,Risk Assessment ,Waste Disposal, Fluid ,Surface-Active Agents ,Rivers ,Animals ,Environmental Chemistry ,Ecotoxicology ,Periphyton ,Water pollution ,Waste Management and Disposal ,Effluent ,Ohio ,Population Density ,No-Observed-Adverse-Effect Level ,Chemistry ,Environmental engineering ,Sediment ,Biodiversity ,Invertebrates ,Pollution ,Alkanesulfonic Acids ,Wastewater ,Benthic zone ,Surface water ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
Alkyl sulfates (AS), alkyl ethoxysulfates (AES) and linear alkyl benzene sulfonates (LAS) are all High Production Volume (HPV) and 'down-the-drain' chemicals used globally in detergent and personal care products, resulting in low levels ultimately released to the environment via wastewater effluent. Due to their surfactant properties, they preferentially sorb to sediments. Hence, assessment of their levels and potential perturbations on benthos are of interest. The relative levels of AS/AES decreased with distance from the wastewater treatment plant outfall. However, this was not evident for LAS. Short chained AES and especially AS dominated the homologue distribution for AES. There were no evident patterns in LAS homologue distribution. The overall mean margin of exposure (MoE) for AS/AES and LAS is approximately 40 (range: 3 to 100) suggesting no noteworthy perturbation on biota. The findings in this study are in concordance with previous preliminary hazard screening. Comparative sediment contamination analyses principally based on Chapman and Anderson [Chapman PM, Anderson, J. A decision-making framework for sediment contamination. Integr Environ Assess Mana. 2005; 1: 163-173.] and the U.S. Environmental Protection Agency RAPID assessment methods [USEPA. Rapid bioassessment protocols for use in wadeable streams and rivers: Periphyton, benthic, macroinvertebrates, and fish. 1999. Second Edition. U.S. Environmental Protection Agency Office of Water, Washington, D.C. EPA 841-B-99-002.] did not reveal significant correlations between the surfactant concentrations and ecological status of the sampling locations. Several Lines of Evidence (LoE) of the Weight-of-Evidence (WoE) lead to the conclusion of low aquatic risk associated to the monitored compounds.
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- 2006
10. Occurrence and hazard screening of alkyl sulfates and alkyl ethoxysulfates in river sediments
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Allen M. Nielsen, Alvaro J. Decarvalho, David A. Robaugh, Hans Sanderson, Scott W. Waite, Bradford B. Price, K. Alex Evans, Morrall Stephen William, Scott D. Dyer, and Manuel L. Cano
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chemistry.chemical_classification ,Pollutant ,Geologic Sediments ,Environmental Engineering ,Chemistry ,Sediment ,Sorption ,Sulfuric Acid Esters ,Pollution ,Hazardous Substances ,Ethyl Ethers ,Surface-Active Agents ,chemistry.chemical_compound ,Rivers ,Wastewater ,Dry weight ,Environmental chemistry ,Environmental Chemistry ,Sulfate ,Water pollution ,Waste Management and Disposal ,Water Pollutants, Chemical ,Alkyl ,Environmental Monitoring - Abstract
Alkyl sulfates (AS) and alkyl ethoxysulfates (AES) are High Production Volume (HPV) ‘down-the-drain’ chemicals widely used globally in detergent and personal care products, resulting in low levels (ng to μg L − 1 range) ultimately released to the environment via wastewater. These surfactants have a strong affinity for sorption to sediments. However, data regarding the fate and effects following release into the environment has not been reported. Sediment samples from both normal exposed and presumably low exposed locations (background) were analyzed to determine the levels of AS/AES. The method used in this study shows broad applicability across various sediment types and the most common congeners of AS/AES. The combined levels of AS/AES detected in the two presumed lower exposed sites ranged from 0.025 and 0.034 μg g − 1 on a dry weight (dw) basis while the presumed higher exposed site had combined levels of AS/AES of 0.117 μg g − 1 (dw) based on triplicate analyses. Results indicate that detectable levels of AS/AES can be found in sediments in the environment at these three sites that are below the concentrations expected to produce significant adverse ecological effects for individual homologues and the whole mixture, the hazard screening for these three sites had PEC porewater /PNEC total mixture ratios of 0.007–0.024. However, further investigation of potential effects and risk assessment is warranted.
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- 2006
11. Investigation of an onsite wastewater treatment system in sandy soil: Site characterization and fate of anionic and nonionic surfactants
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Allen M. Nielsen, Damann L. Anderson, Drew C. McAvoy, Lou Kravetz, Alvaro J. Decarvalho, and Manuel L. Cano
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Chemistry ,Water table ,Health, Toxicology and Mutagenesis ,media_common.quotation_subject ,Septic tank ,Silt ,chemistry.chemical_compound ,Environmental chemistry ,Soil water ,Vadose zone ,Environmental Chemistry ,Sulfate ,Water pollution ,Groundwater ,media_common - Abstract
This study reports on the fate of linear alkylbenzene sulfonate (LAS), alcohol ethoxylate (AE), and alcohol ether sulfate (AES) surfactants in a home septic system near Jacksonville (FL, USA) that has been used since 1976. The drainfield at this site resides in fine sand (
- Published
- 2002
12. Investigation of an onsite wastewater treatment system in sandy soil: Modeling the fate of surfactants
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Allen M. Nielsen, Manuel L. Cano, Alvaro J. Decarvalho, and Drew C. McAvoy
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Health, Toxicology and Mutagenesis ,media_common.quotation_subject ,Septic tank ,Biodegradation ,Anoxic waters ,Onsite sewage facility ,Environmental chemistry ,Environmental Chemistry ,Environmental science ,Drainage ,Water pollution ,Laundry detergent ,Groundwater ,media_common - Abstract
Field monitoring data for three common laundry detergent surfactants were used to test the applicability of a mathematical model that was developed as a screening-level tool for predicting the fate and transport of consumer product ingredients in septic systems. This model takes into account the simultaneous effects of sorption and biodegradation on the transport of chemicals through a septic system. Predicted groundwater concentrations of alcohol ethoxylate (AE) and alcohol ethoxy sulfate (AES) surfactants were in excellent agreement with measured values. This good agreement was to some extent due to the fact that the biodegradation rates of AE and AES do not vary significantly as a function of the degree of oxygenation of the soil. However, using laboratory-measured soil biodegradation rates for linear alkylbenzene sulfonate (LAS), the model underpredicted measured LAS concentrations in groundwater downgradient from the drainage field. This underprediction was due to the fact that the groundwater beneath the drainage field was anoxic during certain parts of the year and LAS is not degradable under this condition. Measured LAS concentrations were consistent with an assumed in situ soil biodegradation rate that was lower than the rate measured under fully oxygenated laboratory conditions. A limitation of the model is that only one soil biodegradation rate can be input for the saturated zone, even though biodegradation rates may vary seasonally or with distance from the drainage field. However, the model was appropriate and useful as a screening tool for the sorbable organic compounds studied. The applicability of the model to other classes of compounds should be assessed before broader application.
- Published
- 2002
13. Investigation of an onsite wastewater treatment system in sandy soil: Sorption and biodegradation of linear alkylbenzene sulfonate
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Drew C. McAvoy, Louis Kravetz, Manuel L. Cano, Alvaro J. Decarvalho, Allen M. Nielsen, Kay H. Marks, and Jon Doi
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Soil test ,Health, Toxicology and Mutagenesis ,media_common.quotation_subject ,Septic tank ,Sorption ,Mineralization (soil science) ,Biodegradation ,complex mixtures ,Onsite sewage facility ,Environmental chemistry ,Soil water ,Environmental Chemistry ,Environmental science ,Groundwater ,media_common - Abstract
The objective of this work was to determine the sorptive and biodegradable characteristics of linear alkylbenzene sulfonate (LAS) in a soil below a Florida, USA, septic system drainfield. Three distinct soil samples were collected from the septic system drainfield study site. These soils were used in laboratory sorption and biodegradation studies. Different concentrations of LAS were added, in radiolabeled and unlabeled forms, to a series of test vessels that contained upgradient groundwater and the soils collected from the study site. The sorption test was designed to determine the partitioning of LAS between groundwater and soil in each sample. Results indicated that the sorption distribution coefficient (K d ) decreased from 4.02 to 0.43 L/kg and that the rate of ultimate biodegradation (first-order rate constant, k 1 ) decreased from 2.17 to 0.08/d with increasing distance (0.7-1.2 m vertically below ground surface [BGS] and 0 to 6.1 m horizontally) from the drainfield. The three soils showed 49.8 to 83.4% LAS mineralization (percentage of theoretical CO 2 ) over 45- or 59-d test periods. These results demonstrate that subsurface soils in this system have the potential to sorb and biodegrade LAS.
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- 2002
14. Biodegradation of Coproducts of Commercial Linear Alkylbenzene Sulfonate
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Geoffrey L. Russell, Allen M. Nielsen, Timothy P. McCormick, Larry N. Britton, and Charles E. Beall
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chemistry.chemical_compound ,Linear alkylbenzene sulfonate ,Sulfonate ,Chromatography ,chemistry ,Aquatic environment ,Coproduct ,food and beverages ,Environmental Chemistry ,Organic chemistry ,General Chemistry ,Biodegradation - Abstract
Dialkyltetralin sulfonate (DATS) and single methyl-branched isomers of linear alkylbenzene sulfonate (iso-LAS) are coproducts that together can range from 1 to 10% of com mercial LAS depending on t...
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- 1997
15. Occurrence and risk screening of alcohol ethoxylate surfactants in three U.S. river sediments associated with wastewater treatment plants
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Kathleen Stanton, Darci Ferrer, Allen M. Nielsen, Bradford B. Price, Martin Selby, Remi van Compernolle, Scott D. Dyer, and Hans Sanderson
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Geologic Sediments ,Environmental Engineering ,Alcohol ethoxylates ,Context (language use) ,Wastewater ,Risk Assessment ,Waste Disposal, Fluid ,Mass Spectrometry ,Surface-Active Agents ,Rivers ,Environmental Chemistry ,Humans ,Aliphatic alcohols ,Waste Management and Disposal ,Chromatography, High Pressure Liquid ,Total suspended solids ,Abiotic component ,Animal fat ,Chemistry ,Weight-of-evidence assessment ,Fatty Acids ,Modeling ,Biota ,Pollution ,Environmental risk ,United States ,Ethoxylation ,Environmental chemistry ,Alcohols ,Sewage treatment ,Risk assessment ,Water Pollutants, Chemical - Abstract
Alcohol ethoxylates (AE) are high production volume (HPV) chemicals globally used in detergent and personal care products and are truly a work-horse for the household and personal care industries. Commercial AE generally consist of a mixture of several homologues of varying carbon chain length and degree of ethoxylation. Homologues that are not ethoxylated are also known as aliphatic alcohols or simply fatty alcohols (FA). This group of homologues represents a special interest in the context of environmental risk, as these are also abundant and ubiquitous naturally occurring compounds (e.g. animal fats and in human feces). Hence, in a risk assessment one needs to distinguish between the natural (background) concentrations and the added contribution from anthropogenic activities. We conducted a weight-of-evidence risk assessment in three streams, documenting the exposure and predicted risk, and compared these to the habitat and in situ biota. We found that the parameters (e.g., habitat quality and total perturbations hereunder total suspended solids (TSS) and other abiotic and biotic stressors) contributed to the abundance of biota rather than the predicted risk from AE and FA. Moreover, the documented natural de novo synthesis and rapid degradation of FA highlight the need to carefully consider the procedures for environmental risk assessment of naturally occurring compounds such as FA, e.g. in line with the added risk concept known from metal risk assessment.
- Published
- 2013
16. Environmental monitoring for linear alkylbenzene sulfonates, dialkyltetralin sulfonates and their biodegradation intermediates
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Michael L. Trehy, John E. Adamove, Allen M. Nielsen, Herbert O. Perkins, James P. Mieure, W.S. Eckhoff, and William E. Gledhill
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Chromatography ,Linear alkylbenzene ,Health, Toxicology and Mutagenesis ,Trickling filter ,Biodegradation ,Rotating biological contactor ,chemistry.chemical_compound ,Activated sludge ,chemistry ,Environmental chemistry ,parasitic diseases ,Environmental Chemistry ,Sewage treatment ,Water pollution ,Effluent - Abstract
Concentrations of linear alkylbenzene sulfonates (LAS), dialkyltetralin sulfonates (DATS), and their biodegradation intermediates are reported for the influents and effluents of 10 U.S. domestic wastewater treatment plants as well as upstream and downstream river waters and sediments. Three types of treatment facilities in 10 U.S. states were sampled and analyzed. Removals were calculated based on initial concentrations of LAS and DATS. A derivatization electron capture/gas chromatography/mass spectrometry method was employed. Its increased sensitivity and selectivity permitted the determination of environmental levels of LAS, DATS, and their biodegradation intermediates at low micrograms per liter (ppb) concentrations. The removal from four activated sludge and five trickling filter wastewater treatment facilities averaged 99.5% and 82.9% for LAS and 99.1% and 97.3% for LAS intermediates, respectively, for the activated sludge and trickling filter facilities. In the same plants, percent removals for DATS averaged 95% and 63.2% and DATS intermediates 59.1% and 58.7%, respectively. The removals obtained by a rotating biological contactor were similar to those observed in the activated sludge wastewater treatment facilities.
- Published
- 1996
17. References
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Stephen M Mudge, Scott E Belanger, and Allen M Nielsen
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- 2008
18. Assessment of the environmental risk of long-chain aliphatic alcohols
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Peter R. Fisk, Yutaka Kasai, Andreas Willing, Scott E. Belanger, Scott D. Dyer, Stephen M. Mudge, Christoph Schäfers, Allen M. Nielsen, Hans Sanderson, and R. Toy
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Canada ,Health, Toxicology and Mutagenesis ,Daphnia magna ,Quantitative Structure-Activity Relationship ,Alcohol ,Risk Assessment ,Aquatic toxicology ,chemistry.chemical_compound ,Animals ,Effluent ,biology ,Sewage ,Public Health, Environmental and Occupational Health ,General Medicine ,Environmental exposure ,Biodegradation ,biology.organism_classification ,Pollution ,United States ,Europe ,Biodegradation, Environmental ,chemistry ,Wastewater ,Daphnia ,Environmental chemistry ,Sewage treatment ,Environmental Pollutants ,Fatty Alcohols ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
An environmental assessment of long-chain alcohols (LCOH) has recently been conducted under the OECD SIDS High Production Volume (HPV) Program via the Global International Council of Chemical Associations (ICCA) Aliphatic Alcohols Consortium. LCOH are used primarily as intermediates, as a precursor to alcohol-based surfactants and as alcohol per se in a wide variety of consumer product applications. Global production volume is approximately 1.58 million metric tonnes. The OECD HPV assessment covers linear to slightly branched LCOH ranging from 6 to 22 alkyl carbons (C). LCOH biodegrade exceptionally rapidly in the environment (half-lives on the order of minutes); however, due to continuous use and distribution to wastewater treatment systems, partitioning properties, biodegradation of alcohol-based surfactants, and natural alcohol sources, LCOH are universally detected in wastewater effluents. An environmental risk assessment of LCOH is presented here by focusing on the most prevalent and toxic members of the linear alcohols, specifically, from C 12−15 . The assessment includes environmental monitoring data for these chain lengths in final effluents of representative wastewater treatment plants and covers all uses of alcohol (i.e., the use of alcohol as a substance and as an intermediate for the manufacturing of alcohol-based surfactants). The 90th percentile effluent discharge concentration of 1.979 μg/L (C 12 −C 15 ) was determined for wastewater treatment plants in 7 countries. Chronic aquatic toxicity studies with Daphnia magna demonstrated that between C 13 and C 15 LCOH solubility became a factor and that the structure–activity relationship was characterized by a toxicity maximum between C 13 and C 14 . Above C 14 the LCOH was less toxic and become un-testable due to insolubility. Risk quotients based on a toxic units (TU) approach were determined for various scenarios of exposure and effects extrapolation. The global average TU ranged from 0.048 to 0.467 depending on the scenario employed suggesting a low risk to the environment. The fact that environmental exposure calculations include large fractions of naturally derived alcohol from animal, plant, and microbially mediated biotransformations further supports a conclusion of low risk.
- Published
- 2008
19. Assessment of alcohol ethoxylate surfactants and fatty alcohols mixtures in river sediments and prospective risk assessment
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Allen M. Nielsen, Hans Sanderson, Remi van Compernolle, Alex Evans, Scott W. Waite, Andrew J. Sherren, Bradford B. Price, Scott D. Dyer, Dennis J. Hooton, and Alvaro J. Decarvalho
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Geologic Sediments ,Fatty alcohol ,Alcohol ,Management, Monitoring, Policy and Law ,Risk Assessment ,Mass Spectrometry ,chemistry.chemical_compound ,Surface-Active Agents ,Rivers ,Liquid chromatography–mass spectrometry ,Ecotoxicology ,Derivatization ,General Environmental Science ,Detection limit ,Chromatography ,Sewage ,Extraction (chemistry) ,General Medicine ,Pollution ,chemistry ,Environmental chemistry ,Alcohols ,Composition (visual arts) ,Fatty Alcohols ,Water Pollutants, Chemical ,Chromatography, Liquid ,Environmental Monitoring - Abstract
A feasible and relatively readily available analytical method was adapted for the assessment of alcohol ethoxylates (AE) and fatty alcohols (FA) in sediments. This study illustrates the simultaneous measurement of 38 of 114 possible alcohol ethoxylate ethoxymers (AE) and fatty alcohols (FA) found in commercially important AE products. We predicted toxicity for all identified fractions, as well as the total mixture toxicity, relative to three exposure scenarios via sewage treatment plants (STP) for these widely used chemicals in consumer products and hence generate a preliminary environmental risk screening for AE and FA in sediments. The method is based on derivatization of solvent or solid-phase extracts with 2-fluoro-N-methylpyridinium p-toluenesulfonate (Pyr+). The derivatized extracts were analyzed with liquid chromatography/mass spectrometry (LC/MS) operating in the positive ion electrospray mode. The extraction efficiency of AE and FA in three different sediments of varying composition was evaluated with spike-recovery studies, ranging from 64% to 80%. The detection limits for individual ethoxymers typically ranged from 1 to 5 ngg(-1)on a dry weight basis. The mean limit of detection (LOD) was 6 ngg(-1)and the median LOD was 3 ngg(-1). AE and FA in sediments were found to be stable for two weeks if preserved with 3% (v/v) formalin and stored at 4-6( composite function)C. Based on equilibrium partitioning, background concentrations of AE and FA were predicted to be below concentrations known to elicit chronically toxic effects. Total worst case mixture toxicities for all AE ethoxymers combined with FA were predicted to result in a risk quotient less than 0.6. Activated sludge treatment (STP) significantly reduced the release of total AE and FA by four-fold, suggesting that the total mixture risk quotient would be0.15 for sediment dependent organisms.
- Published
- 2005
20. Investigation of an onsite wastewater treatment system in sandy soil: sorption and biodegradation of linear alkylbenzene sulfonate
- Author
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Jon, Doi, Kay H, Marks, Alvaro J, DeCarvalho, Drew C, McAvoy, Allen M, Nielsen, Louis, Kravetz, and Manuel L, Cano
- Subjects
Surface-Active Agents ,Biodegradation, Environmental ,Alkanesulfonic Acids ,Soil Pollutants ,Water Pollutants ,Adsorption ,Silicon Dioxide ,Waste Disposal, Fluid - Abstract
The objective of this work was to determine the sorptive and biodegradable characteristics of linear alkylbenzene sulfonate (LAS) in a soil below a Florida, USA, septic system drainfield. Three distinct soil samples were collected from the septic system drainfield study site. These soils were used in laboratory sorption and biodegradation studies. Different concentrations of LAS were added, in radiolabeled and unlabeled forms, to a series of test vessels that contained upgradient groundwater and the soils collected from the study site. The sorption test was designed to determine the partitioning of LAS between groundwater and soil in each sample. Results indicated that the sorption distribution coefficient (Kd) decreased from 4.02 to 0.43 L/kg and that the rate of ultimate biodegradation (first-order rate constant, k1) decreased from 2.17 to 0.08/d with increasing distance (0.7-1.2 m vertically below ground surface [BGS] and 0 to 6.1 m horizontally) from the drainfield. The three soils showed 49.8 to 83.4% LAS mineralization (percentage of theoretical CO2) over 45- or 59-d test periods. These results demonstrate that subsurface soils in this system have the potential to sorb and biodegrade LAS.
- Published
- 2002
21. Preface
- Author
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Stephen M Mudge, Scott E Belanger, and Allen M Nielsen
- Published
- 2008
22. About the Authors
- Author
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Stephen M Mudge, Scott E Belanger, and Allen M Nielsen
- Published
- 2008
23. Photoheterotrophic utilization of acetate by the wild type and an acetate-adapted mutant of Rhodopseudomonas capsulata
- Author
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Allen M. Nielsen and Gary A. Sojka
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chemistry.chemical_classification ,biology ,Strain (chemistry) ,Bicarbonate ,Mutant ,Wild type ,Glyoxylate cycle ,General Medicine ,Isocitrate lyase ,biology.organism_classification ,Biochemistry ,Microbiology ,chemistry.chemical_compound ,Enzyme ,chemistry ,Genetics ,Molecular Biology ,Rhodospirillaceae - Abstract
Rhodopseudomonas capsulata strain St. Louis can grow anaerobically in the light-with acetate as the carbon source. The organism is sensitive to acetate, however, initial concentrations exceeding 25 mM resulting in an extensive growth lag. Bicarbonate is not required for growth of this strain on acetate, but addition of bicarbonate shortens the lag phase in media with high initial acetate concentration. A spontaneous mutant which exhibited a minimal lag phase and rapid growth rates on acetate media was derived from strain St. Louis. This mutant possessed elevated levels of the glyoxylate cycle enzyme, isocitrate lyase.
- Published
- 1979
24. Regulation of isocitrate lyase in a mutant of Rhodopseudomonas capsulata adapted to growth on acetate
- Author
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Brian J. Rampsch, Gary A. Sojka, and Allen M. Nielsen
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chemistry.chemical_classification ,Strain (chemistry) ,Chemistry ,Mutant ,Wild type ,Glyoxylate cycle ,General Medicine ,Isocitrate lyase ,Biochemistry ,Microbiology ,Enzyme ,Genetics ,Isocitrate lyase activity ,Rhodopseudomonas capsulata ,Molecular Biology - Abstract
Studies on acetate utilization by Rhodopseudomonas capsulata strain St. Louis indicated that the wild type grew poorly on acetate and made little if any of the glyoxylate cycle enzyme isocitrate lyase. A spontaneous mutant, Ac-l, capable of vigorous and immediate growth on acetate and exhibiting high levels of isocitrate lyase activity, was isolated in the course of those studies.
- Published
- 1979
25. Chalcocite Oxidation and Coupled Carbon Dioxide Fixation by Thiobacillus ferrooxidans
- Author
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Jay V. Beck and Allen M. Nielsen
- Subjects
chemistry.chemical_classification ,Multidisciplinary ,Mineral ,Chalcocite ,Sulfide ,Inorganic chemistry ,Carbon fixation ,chemistry.chemical_element ,engineering.material ,Covellite ,Digenite ,Copper ,chemistry.chemical_compound ,chemistry ,visual_art ,Carbon dioxide ,engineering ,visual_art.visual_art_medium - Abstract
The reaction of cell suspensions of Thiobacillus ferrooxidans with pulverized chalcocite (Cu(2)S) in a Warburg manometric apparatus resulted in oxygen uptake accompanied by increased solubilization of copper and fixation of carbon dioxide. Since the only detectable oxidized products were cupric ions and the more oxidized form of the sulfide mineral, that is, digenite or covellite, the apparent source of energy for the carbon dioxide fixation was provided by the oxidation of the cuprous copper of the chalcocite.
- Published
- 1972
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