title: Spatial patterns of atmospherically deposited organic contaminants at high elevation in the southern Sierra Nevada mountains, California, USA.
abstract: Atmospherically deposited contaminants in the Sierra Nevada mountains of California, USA have been implicated as adversely affecting amphibians and fish, yet little is known about the distributions of contaminants within the mountains, particularly at high elevation. The hypothesis that contaminant concentrations in a high-elevation portion of the Sierra Nevada decrease with distance from the adjacent San Joaquin Valley was tested. Air, sediment, and tadpoles were sampled twice at 28 water bodies in 14 dispersed areas in Sequoia and Kings Canyon National Parks (2,785-3,375 m elevation; 43-82 km from Valley edge). Up to 15 chemicals were detected frequently in sediment and tadpoles, including current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Only beta-endosulfan was found frequently in air. Concentrations of all chemicals detected were very low, averaging in the parts-per-billion range or less in sediment and tadpoles, and on the order of 10 pg/m3 for beta-endosulfan in air. Principal components analysis indicated that chemical compositions were generally similar among sites, suggesting that chemical transport patterns were likewise similar among sites. In contrast, transport processes did not appear to strongly influence concentration differences among sites, because variation in concentrations among nearby sites was high relative to sites far from each other. Moreover, a general relationship for concentrations as a function of distance from the valley was not evident across chemical, medium, and time. Nevertheless, concentrations for some chemical/medium/time combinations showed significant negative relationships with metrics for distance from the Valley. However, the magnitude of these distance effects among high-elevation sites was small relative to differences found in other studies between the valley edge and the nearest high-elevation sites.
authors.affiliation: U.S. Environmental Protection Agency, National Exposure Research Laboratory, 944 East Harmon Avenue, Las Vegas, Nevada 89119, USA. bradford.david@epa.gov
authors.forename: David F
authors.initials: DF
authors.lastname: Bradford
authors.forename: Kerri
authors.initials: K
authors.lastname: Stanley
authors.forename: Laura L
authors.initials: LL
authors.lastname: McConnell
authors.forename: Nita G
authors.initials: NG
authors.lastname: Tallent-Halsell
authors.forename: Maliha S
authors.initials: MS
authors.lastname: Nash
authors.forename: Staci M
authors.initials: SM
authors.lastname: Simonich
mesh_terms: D000393:Air Pollutants / Q000737:chemistry* / Q000378:metabolism; D000531:Altitude; D000818:Animals; D001001:Anura / Q000378:metabolism; D001272:Atmosphere; D002140:California; D004784:Environmental Monitoring; D007814:Larva / Q000378:metabolism
chemical_list: D000393:Air Pollutants
references.citation: Pestic Monit J. 1970 Mar;3(4):204-11
references.pmid: 5435548
references.citation: Environ Sci Technol. 2006 May 15;40(10):3174-80
references.pmid: 16749678
references.citation: Environ Sci Technol. 2002 Oct 1;36(19):4142-51
references.pmid: 12380087
references.citation: Environ Toxicol Chem. 2001 Jul;20(7):1591-5
references.pmid: 11434303
references.citation: Environ Sci Technol. 2008 Apr 1;42(7):2334-41
references.pmid: 18504962
references.citation: Bull Environ Contam Toxicol. 1998 Jun;60(6):829-36
references.pmid: 9606257
references.citation: Environ Toxicol Chem. 2002 Oct;21(10):2209-15
references.pmid: 12371500
references.citation: Environ Sci Technol. 2005 Jan 15;39(2):385-98
references.pmid: 15707037
references.citation: J Environ Qual. 2004 Sep-Oct;33(5):1752-64
references.pmid: 15356235
references.citation: Environ Toxicol Chem. 2009 Aug;28(8):1696-703
references.pmid: 19290680
references.citation: Environ Toxicol Chem. 2004 Sep;23(9):2170-7
references.pmid: 15378994
references.citation: Environ Sci Technol. 2007 Nov 1;41(21):7235-41
references.pmid: 18044494
references.citation: Environ Toxicol Chem. 2009 Oct;28(10):2038-43
references.pmid: 19432502
references.citation: Environ Toxicol Chem. 2002 May;21(5):984-90
references.pmid: 12013145
references.citation: Ecol Appl. 2007 Mar;17(2):587-97
references.pmid: 17489262
references.citation: Environ Sci Technol. 2004 Sep 1;38(17):4474-83
references.pmid: 15461152
references.citation: J Agric Food Chem. 2001 Nov;49(11):5372-6
references.pmid: 11714330