000158295 001__ 158295
000158295 005__ 20180317093907.0
000158295 0247_ $$2doi$$a10.1021/es970637r
000158295 022__ $$a0013936X
000158295 02470 $$2Scopus$$a2-s2.0-0032033085
000158295 037__ $$aARTICLE
000158295 245__ $$aRapid oxidation of geothermal arsenic(III) in streamwaters of the eastern Sierra Nevada
000158295 260__ $$c1998
000158295 269__ $$a1998
000158295 336__ $$aJournal Articles
000158295 520__ $$aArsenic redox cycling was examined in source waters of the Los Angeles Aqueduct, specifically at Hot Creek, a tributary of the Owens River. Elevated arsenic concentrations in Hot Creek result from geothermal inputs. Total arsenic and As(III) concentrations were determined in the creek and in hot spring pools along its banks. Samples were processed in the field using anion-exchange columns to separate inorganic As(III) and As(V) species. Downstream of the geothermal inputs, decreasing contributions of As(III) to total arsenic concentrations indicated rapid in-stream oxidation of As(III) to As(V) with almost complete oxidation occurring within 1200 m. Based on assumed plug flow transport and a flow velocity of about 0.4 m/s, the pseudo- first-order half-life calculated for this reaction was approximately 0.3 h. Conservative transport of total dissolved arsenic was observed over the reach. Pseudo-first-order reaction rates determined for As(III) oxidation in batch studies conducted in the field with aquatic macrophytes and/or macrophyte surface matter were comparable to the in-stream oxidation rate observed along Hot Creek. In batch kinetic studies, oxidation was not observed after sterile filtration or after the addition of antibiotics, which indicates that bacteria attached to submerged macrophytes are mediating the rapid As(III) oxidation reaction. | Arsenic redox cycling was examined in source waters of the Los Angeles Aqueduct, specifically at Hot Creek, a tributary of the Owens River. Elevated arsenic concentrations in Hot Creek result from geothermal inputs. Total arsenic and As(III) concentrations were determined in the creek and in hot spring pools along its banks. Samples were processed in the field using anion-exchange columns to separate inorganic As(III) and As(V) species. Downstream of the geothermal inputs, decreasing contributions of As(III) to total arsenic concentrations indicated rapid in-stream oxidation of As(III) to As(V) with almost complete oxidation occurring within 1200 m. Based on assumed plug flow transport and a flow velocity of about 0.4 m/s, the pseudo-first-order half-life calculated for this reaction was approximately 0.3 h. Conservative transport of total dissolved arsenic was observed over the reach. Pseudo-first-order reaction rates determined for As(III) oxidation in batch studies conducted in the field with aquatic macrophytes and/or macrophyte surface matter were comparable to the in-stream oxidation rate observed along Hot Creek. In batch kinetic studies, oxidation was not observed after sterile filtration or after the addition of antibiotics, which indicates that bacteria attached to submerged macrophytes are mediating the rapid As(III) oxidation reaction.
000158295 700__ $$aWilkie, J.A.
000158295 700__ $$0244343$$aHering, J.G.$$g178483
000158295 773__ $$j32$$k5$$q657-662$$tEnvironmental Science and Technology
000158295 909CO $$ooai:infoscience.tind.io:158295$$pENAC$$particle
000158295 909C0 $$0252298$$pUPHCE$$xU12328
000158295 937__ $$aEPFL-ARTICLE-158295
000158295 973__ $$aOTHER$$rREVIEWED$$sPUBLISHED
000158295 980__ $$aARTICLE