Dynamic Colloid-Water Partitioning of Pyrene through a Coastal Baltic Spring Bloom

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• 作者：&Ouml ; rjan Gustafsson ; Nina Nilsson ; and Thomas D. Bucheli
• 刊名：Environmental Science & Technology
• 出版年：2001
• 出版时间：October 15, 2001
• 年：2001
• 卷：35
• 期：20
• 页码：4001 - 4006
• 全文大小：107K
• 年卷期：v.35,no.20(October 15, 2001)
• ISSN：1520-5851

文摘

Colloidal organic particles constitute the dominant portionof particulate organic matter in surface seawater, buttheir influence on the phase speciation and bioavailabilityof hydrophobic organic compounds (HOCs) is sparselyevaluated. Studies on colloid-water partitioning have beenfocused on other regimes and have largely been performedon chemically defined subportions of total colloids suchas the humic fraction. Available estimates of colloid-waterpartition coeffficients (K_coc) are highly variable and noteasily explained by regularly applied K_ow-K_oc relationships.Here, pyrene was partitioned to bulk natural colloidsisolated using cross-flow ultrafiltration techniques fromthe surface water of a coastal bay. A key objective wasto elucidate biogeochemical controls on the changing colloid-sorbent qualities over the course of the dynamicallochtonous-autochtonous transition of a well-constrainedboreal coastal spring bloom. The pyrene K_coc was foundto decrease from 12.9 ± 0.9 × 10³ L_w/kg_oc in the terrestrialrunoff dominated regime to values around 2.9 ± 0.7 ×10³ L_w/kg_oc, once phytoplankton production became thegoverning source of organic matter to the surface waters.The changing K_coc was well correlated with the molarextinction coefficient at 280 nm of the colloidal organiccarbon. This study supports other reports of an improvedprediction of HOC phase speciation through this simplemolecular proxy of the "quality" of organic sorbents. Whilebeing poor sorbents on a carbon atom basis, relative tosoils and sediments, coastal marine colloids, by their shearabundance, may significantly attenuate the truly dissolvedexposures of HOCs with log K_ow above 5.