| Abstract: | Statistical evaluation of two large statewide data sets from the California State Water Board‘s Groundwater Ambient Monitoring and Assessment Program (1973 wells) and the California Department of Public Health (12417 wells) reveals that benzene occurs infrequently (1.7%) and at generally low concentrations (median detected concentration of 0.024 μg/L) in groundwater used for public supply in California. When detected, benzene is more often related to geogenic (45% of detections) than anthropogenic sources (27% of detections). Similar relations are evident for the sum of 17 hydrocarbons analyzed. Benzene occurs most frequently and at the highest concentrations in old, brackish, and reducing groundwater; the detection frequency was 13.0% in groundwater with tritium <1 pCi/L, specific conductance >1600 μS/cm, and anoxic conditions. This groundwater is typically deep (>180 m). Benzene occurs somewhat less frequently in recent, shallow, and reducing groundwater; the detection frequency was 2.6% in groundwater with tritium ≥1 pCi/L, depth <30 m, and anoxic conditions. Evidence for geogenic sources of benzene include: higher concentrations and detection frequencies with increasing well depth, groundwater age, and proximity to oil and gas fields; and higher salinity and lower chloride/iodide ratios in old groundwater with detections of benzene, consistent with interactions with oil-field brines. |
| Genre: | Article |
| ProdID: | 70040152 |
| Citation Author: | Belitz, Kenneth; Landon, Matthew K. |
| Citation Contributing Office: | California Water Science Center |
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| Citation End Page: | 8697 |
| Citation Issue: | 16 |
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| Citation Language: | English |
| Citation Larger Work Title: | Environmental Science and Technology |
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| Citation Number Of Pages: | 9 |
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| Citation Phsyical Description: | 8 p. |
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| Citation Publisher: | ACS Publications |
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| Citation Search Results Text: | Geogenic sources of benzene in aquifers used for public supply, California; 2012; Article; Journal; Environmental Science and Technology; Belitz, Kenneth; Landon, Matthew K. |
| Citation Start Page: | 8689 |
| Citation Volume: | 46 |
| Citation Year: | 2012 |
| Type: | citation/reference |
| Text: | Geogenic sources of benzene in aquifers used for public supply, California; 2012; Article; Journal; Environmental Science and Technology; Belitz, Kenneth; Landon, Matthew K. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1021/es302024c |
| Date Other: | Wed, 3 Oct 2012 00:00 -0500 |
| Publisher: | ACS Publications |
