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Occurrence and photochemical fate of...

Plumlee, Megan H.

Occurrence and photochemical fate of emerging contaminants: Nitrosamines and perfluorochemicals.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Occurrence and photochemical fate of emerging contaminants: Nitrosamines and perfluorochemicals.
作者:	Plumlee, Megan H.
面頁冊數:	104 p.
附註:	Source: Dissertation Abstracts International, Volume: 69-10, Section: B, page: .
Contained By:	Dissertation Abstracts International69-10B.
標題:	Environmental Sciences.
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3332907
ISBN:	9780549847021

Occurrence and photochemical fate of emerging contaminants: Nitrosamines and perfluorochemicals.
Plumlee, Megan H.

Occurrence and photochemical fate of emerging contaminants: Nitrosamines and perfluorochemicals. - 104 p.

Source: Dissertation Abstracts International, Volume: 69-10, Section: B, page: .

Thesis (Ph.D.)--Stanford University, 2008.

For perfluorochemicals, selected perfluoroalkanesulfonamides were irradiated in aqueous hydrogen peroxide solutions using artificial sunlight to simulate aquatic environmental conditions. Indirect photolysis mediated by hydroxyl radical was observed for N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE), N-ethyl perfluorooctane sulfonamido acetate (N-EtFOSAA), N-ethyl perfluorooctane sulfonamide (N-EtFOSA), and perfluorooctane sulfonamide acetate (FOSAA). A proposed reaction pathway for degradation of the parent perfluorochemical, N-EtFOSE, to the other perfluoroalkanesulfonamides, perfluorooctane sulfonamide (FOSA), and PFOA was developed and includes oxidation and N-dealkylation steps. As they did not undergo additional degradation, FOSA and PFOA were the final degradation products of hydroxyl radical-mediated indirect photolysis. UV-visible absorption spectra for the perfluorochemicals, showing absorbance in the UV region below the range of natural sunlight, are also reported. Given the slow rates that have been observed for biodegradation and limited sorption, indirect photolysis of perfluorochemicals may be important in the determination of their environmental fate.

ISBN: 9780549847021Subjects--Topical Terms:

212393
Environmental Sciences.

Occurrence and photochemical fate of emerging contaminants: Nitrosamines and perfluorochemicals.
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100 $a Plumlee, Megan H. $3 321904
245 1 0 $a Occurrence and photochemical fate of emerging contaminants: Nitrosamines and perfluorochemicals.
300 $a 104 p.
500 $a Source: Dissertation Abstracts International, Volume: 69-10, Section: B, page: .
502 $a Thesis (Ph.D.)--Stanford University, 2008.
520 $a For perfluorochemicals, selected perfluoroalkanesulfonamides were irradiated in aqueous hydrogen peroxide solutions using artificial sunlight to simulate aquatic environmental conditions. Indirect photolysis mediated by hydroxyl radical was observed for N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE), N-ethyl perfluorooctane sulfonamido acetate (N-EtFOSAA), N-ethyl perfluorooctane sulfonamide (N-EtFOSA), and perfluorooctane sulfonamide acetate (FOSAA). A proposed reaction pathway for degradation of the parent perfluorochemical, N-EtFOSE, to the other perfluoroalkanesulfonamides, perfluorooctane sulfonamide (FOSA), and PFOA was developed and includes oxidation and N-dealkylation steps. As they did not undergo additional degradation, FOSA and PFOA were the final degradation products of hydroxyl radical-mediated indirect photolysis. UV-visible absorption spectra for the perfluorochemicals, showing absorbance in the UV region below the range of natural sunlight, are also reported. Given the slow rates that have been observed for biodegradation and limited sorption, indirect photolysis of perfluorochemicals may be important in the determination of their environmental fate.
520 $a In the present study, the occurrence of two classes of organic contaminants, the N-nitrosamines and perfluorochemicals, was determined in reclaimed wastewater and the aqueous photolytic behavior of these compounds was characterized. Six nitrosamines, including N-nitrosodimethylamine (NDMA), were surveyed at the Interim Water Purification Facility (IWPF), an advanced wastewater treatment facility that reclaimed effluent from an activated sludge treatment plant and treated it for injection into a coastal aquifer as a hydraulic seawater barrier. Only NDMA was detected and at all treatment steps in the IWPF, with influent concentrations ranging from 20 to 59 ng/L. Removals for reverse osmosis and ultraviolet treatment ranged from 24 to 56% and 43 to 66%, respectively. Overall, 69+/-7% of the original NDMA concentration was removed from the product water across the advanced treatment process and, in combination with blending, the final concentration did not exceed the California drinking water notification level of 10 ng/L.
520 $a The concentration and distribution of perfluorochemicals were characterized in reclaimed wastewater from four California wastewater treatment plants that employ tertiary treatment and one that treats primary sewage in a wetland constructed for both treatment and wildlife habitat. Effluent concentrations were compared with surface and groundwater from a creek where reclaimed wastewater was evaluated as a potential means to augment flow (Upper Silver and Coyote Creeks, San Jose, CA). In the reclaimed wastewater, 90-470 ng/L perfluorochemicals were detected, predominantly perfluorooctanoate (PFOA; 10-190 ng/L) and perfluorooctanesulfonate (PFOS; 20-190 ng/L). No significant removal of perfluorochemicals was observed in the wetland (total concentration ranged 100-170 ng/L across various treatment stages); in this case, 2-(N-ethylperfluorooctanesulfonamido) acetic acid (N-EtFOSAA), perfluorodecanesulfonate (PFDS), and PFOS were dominant. Though there is currently no wastewater discharge into the creeks, perfluorochemicals were found in the surface water and underlying groundwater at a total of 20-150 ng/L with PFOS and PFOA again making the largest contribution.
520 $a To assess the photochemical fate of these compound classes once they are released into the aquatic environment via wastewater discharge or water reuse, the aqueous photolysis of selected nitrosamines and perfluorochemicals was studied by irradiation in a solar simulator. Nitrosamines included NDMA, N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), N-nitrosodi-n-butylamine (NDBA), N-nitrosopiperidine (NPip), and N-nitrosopyrrolidine (NPyr). Direct photolysis of nitrosamines at irradiations of 765 W/m 2, representing Southern California midsummer, midday sun, resulted in half-lives of 16 min for NDMA and 12-15 min for the other nitrosamines. The quantum yield for NDMA was determined to be phi = 0.41 and phi = 0.43 to 0.61 for the other nitrosamines. Quantified products of NDMA photolysis included methylamine, dimethylamine, nitrite, nitrate, and formate, with nitrogen and carbon balances exceeding 98% and 79%, respectively. Indirect photolysis of nitrosamines in surface water was not observed: increasing dissolved organic carbon (DOC) slowed the NDMA photolysis rate due to light screening. Removal of NDMA measured in tertiary treated effluent flowing in a shallow, sunlit engineered channel agreed with photolysis rates predicted based on the measured quantum yield and system parameters. Because biodegradation is relatively slow, aquatic photolysis of NDMA is generally expected to be more significant even at relatively low levels of solar irradiation (t1/2 = 8-38 h at 244-855 W/m2, 51° N latitude, 1 m depth).
520 $a Wastewater discharged to the aquatic environment is likely to contain trace levels of organic contaminants, some of which may be carcinogens, toxins, or endocrine disruptors. The presence of these microconstituents in the receiving water body may have ecotoxicological consequences, as well as pose potential human health risks when the water is used as a drinking water supply. Water agencies in the U.S. and elsewhere are expanding wastewater reclamation (or water reuse) as part of their water supply portfolio to meet the needs of growing populations. Although water reuse is generally regarded as a sustainable approach to water supply management, the presence of trace organic contaminants raises concerns about the use of this water in applications such as landscaping and environmental enhancement.
590 $a School code: 0212.
650 $a Environmental Sciences. $3 212393
650 $a Engineering, Environmental. $3 212478
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710 $a Stanford University. $3 212607
773 0 $g 69-10B. $t Dissertation Abstracts International
790 $a 0212
791 $a Ph.D.
792 $a 2008
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