The transport and fate of hydrophobic organic contaminants (HOCs) in the marine environment are closely linked to organic carbon (OC) cycling processes. We investigated the influence of marine versus terrestrial OC origin on HOC fluxes at two Baltic Sea coastal sites with different relative contributions of terrestrial and marine OC. Stronger sorption of the more than four-ring polycyclic aromatic hydrocarbons and penta-heptachlorinated polychlorinated biphenyls (PCBs) was observed at the marine OC-dominated site. The site-specific partition coefficients between sediment OC and water were 0.2–1.0 log units higher at the marine OC site, with the freely dissolved concentrations in the sediment pore-water 2–10 times lower, when compared with the terrestrial OC site. The stronger sorption at the site characterized with marine OC was most evident for the most hydrophobic PCBs, leading to reduced fluxes of these compounds from sediment to water. According to these results, future changes in OC cycling because of climate change, leading to increased input of terrestrial OC to the marine system, can have consequences for the availability and mobility of HOCs in aquatic systems and thereby also for the capacity of sediments to store HOCs.

中文翻译：

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有机碳来源对波罗的海疏水性有机污染物归宿的影响

海洋环境中疏水性有机污染物 (HOC) 的迁移和归宿与有机碳 (OC) 循环过程密切相关。我们研究了海洋与陆地 OC 起源对两个波罗的海沿海站点的 HOC 通量的影响，其中陆地和海洋 OC 的相对贡献不同。在海洋 OC 主导的地点观察到四环以上的多环芳烃和五七氯化多氯联苯 (PCB) 的更强吸附。与陆地 OC 站点相比，海洋 OC 站点的沉积物 OC 和水之间的特定站点分配系数高 0.2-1.0 log 单位，沉积物孔隙水中的自由溶解浓度​​低 2-10 倍。以海洋 OC 为特征的地点的更强吸附对于最疏水的 PCB 最为明显，导致这些化合物从沉积物到水的通量降低。根据这些结果，未来由于气候变化导致 OC 循环的变化，导致陆地 OC 对海洋系统的输入增加，可能对水生系统中 HOC 的可用性和流动性产生影响，从而也影响沉积物的储存能力HOC。