| Abstract: | Spatial, temporal, and sediment-type trends in enantiomer signatures were evaluated for cis- and trans-chlordane (CC, TC) in archived core, suspended, and surficial-sediment samples from six lake, reservoir, and river sites across the United States. The enantiomer fractions (EFs) measured in these samples are in good agreement with those reported for sediment, soil, and air samples in previous studies. The chlordane EFs were generally close to the racemic value of 0.5, with CC values ranging from 0.493 to 0.527 (usually >0.5) and TC values from 0.463 to 0.53 (usually <0.5). EF changes with core depth were detected for TC and CC in some cores, with the most non-racemic values near the top of the core. Surficial and suspended sediments generally have EF values similar to the top core layers but are often more non-racemic, indicating that enantioselective degradation is occurring before soils are eroded and deposited into bottom sediments. We hypothesize that rapid losses (desorption or degradation) from suspended sediments of the more bioavailable chlordane fraction during transport and initial deposition could explain the apparent shift to more racemic EF values in surficial and top core sediments. Near racemic CC and TC in the core profiles suggest minimal alteration of chlordane from biotic degradation, unless it is via non-enantioselective processes. EF values for the heptachlor degradate, heptachlor epoxide (HEPX), determined in surficial sediments from one location only were always non-racemic (EF ??? 0.66), were indicative of substantial biotic processing, and followed reported EF trends. |
| Genre: | Article |
| ProdID: | 70037154 |
| Citation Author: | Ulrich, E. M.; Foreman, W. T.; Van Metre, P. C.; Wilson, J. T.; Rounds, S. A. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 5893 |
| Citation Issue: | 22 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Science of the Total Environment |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 10 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Enantiomer fractions of chlordane components in sediment from U.S. Geological Survey sites in lakes and rivers; 2009; Article; Journal; Science of the Total Environment; Ulrich, E. M.; Foreman, W. T.; Van Metre, P. C.; Wilson, J. T.; Rounds, S. A. |
| Citation Start Page: | 5884 |
| Citation Volume: | 407 |
| Citation Year: | 2009 |
| Type: | citation/reference |
| Text: | Enantiomer fractions of chlordane components in sediment from U.S. Geological Survey sites in lakes and rivers; 2009; Article; Journal; Science of the Total Environment; Ulrich, E. M.; Foreman, W. T.; Van Metre, P. C.; Wilson, J. T.; Rounds, S. A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/j.scitotenv.2009.08.023 |
| Date Other: | Thu, 1 Jan 2009 00:00 -0600 |
| Publisher: | |
