Dissolved Organic Carbon in Groundwater Overlain by Irrigated Sugarcane
© 2014, Commonwealth of Australia. Groundwater © 2014, National Ground Water Association.
| Publié dans: | Ground water. - 1979. - 53(2015), 4 vom: 11. Juli, Seite 525-30 |
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| Auteur principal: | |
| Autres auteurs: | , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2015
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| Accès à la collection: | Ground water |
| Sujets: | Journal Article Research Support, Non-U.S. Gov't Nitro Compounds Organic Chemicals Water Pollutants, Chemical Manganese 42Z2K6ZL8P Carbon 7440-44-0 Iron |
| Résumé: | © 2014, Commonwealth of Australia. Groundwater © 2014, National Ground Water Association. Elevated dissolved organic carbon (DOC) has been detected in groundwater beneath irrigated sugarcane on the Burdekin coastal plain of tropical northeast Australia. The maximum value of 82 mg/L is to our knowledge the highest DOC reported for groundwater beneath irrigated cropping systems. More than half of the groundwater sampled in January 2004 (n = 46) exhibited DOC concentrations greater than 30 mg/L. DOC was progressively lower in October 2004 and January 2005, with a total decrease greater than 90% indicating varying load(s) to the aquifer. It was hypothesized that the elevated DOC found in this groundwater system is sourced at or near the soil surface and supplied to the aquifer via vertical recharge following above average rainfall. Possible sources of DOC include organic-rich sugar mill by-products applied as fertilizer and/or sugarcane sap released during harvest. CFC-12 vertical flow rates supported the hypothesis that elevated DOC (>40 mg/L) in the groundwater results from recharge events in which annual precipitation exceeds 1500 mm/year (average = 960 mm/year). Occurrence of elevated DOC concentrations, absence of electron acceptors (O2 and NO3 (-) ) and both Fe(2+) and Mn(2+) greater than 1 mg/L in shallow groundwater suggest that the DOC compounds are chemically labile. The consequence of high concentrations of labile DOC may be positive (e.g., denitrification) or negative (e.g., enhanced metal mobility and biofouling), and highlights the need to account for a wider range of water quality parameters when considering the impacts of land use on the ecology of receiving waters and/or suitability of groundwater for irrigated agriculture |
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| Description: | Date Completed 17.03.2016 Date Revised 03.07.2015 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1745-6584 |
| DOI: | 10.1111/gwat.12258 |