Sources, Vertical Fluxes, and Accumulation of Aliphatic Hydrocarbons in Coastal Sediments of the Río de la Plata Estuary, Argentina
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- 作者：J. C. Colombo ; N. Cappelletti ; J. Lasci ; M. C. Migoya ; E. Speranza ; and C. N. Skorupka
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：November 1, 2005
- 年：2005
- 卷：39
- 期：21
- 页码：8227 - 8234
- 全文大小：571K
- 年卷期：v.39,no.21(November 1, 2005)
- ISSN：1520-5851
文摘
Settling particles and underlying sediments collected at 1,2.5 and 4 km off the metropolitan Buenos Aires coastwere analyzed to evaluate the sources and accumulationof resolved (RES), unresolved (UCM), and biomarkeraliphatic hydrocarbons. Sedimentary aliphatic concentrations(RES 0.11-14 
es/entities/mgr.gif">g·g-1; UCM 0.1-800 es/entities/mgr.gif">g·g-1) includedvariability associated with north-south gradients and anexponential offshore reduction. Highest concentrations wereregistered close to Buenos Aires port and sewer, comparedto cleaner northern stations and southward sites affectedby a seaward residue transport. Sediment traps deployedin the sewer area revealed large hydrocarbon (38 and319 mg·m-2·day-1, RES and UCM) and total organic carbonfluxes (29 ± 26 g·m-2·day-1). The composition of RESand hopanes evaluated by principal component analysisindicated a consistent offshore gradient defined by the relativecontribution of lower vs higher molecular weightcomponents. Distant sites showed decreasing proportionsof petrogenic n-C17-26 alkanes, isoprenoids, and C20-27terpanes and relative enrichment of n-C27,29,31,33 terrestrialplant alkanes and C31-33 homohopanes. Sedimenthydrocarbon profiles showed an average 2-fold reductiondown to 20 cm depth with preferential removal of lowermolecular weight components and enrichment of n-C23-35alkanes and hopanes. Sediment inventories and trapdepositional fluxes indicate the accumulation of 5800-9700 tons of aliphatic hydrocarbons in the top 0-5 cmsediments with a strong interfacial alteration and selectivepreservation of refractory components: n-C13-22 (1.0%)< isoprenoids (3.2%) < n-C23-35 (6.1%) < hopanes (47%)~ UCM (50%), compared to intermediate stability of organiccarbon (12%) and quantitative preservation of polychlorinatedbiphenyls (PCBs) (91%).