Nybom Inna, van Grimbergen Janneke, Forsell Mari, Mustajärvi Lukas, Martens Jannik, Sobek Anna
Stockholm University, Department of Environmental Science, 10691 Stockholm, Sweden.
Stockholm University, Department of Environmental Science, 10691 Stockholm, Sweden.
J Hazard Mater. 2024 Mar 5;465:133393. doi: 10.1016/j.jhazmat.2023.133393. Epub 2024 Jan 6.
The environmental fate of hazardous hydrophobic pollutants in the marine environment is strongly influenced by organic carbon (OC) cycling. As an example, the seasonality in primary production impacts both water column OC quantity and quality, which may influence pollutant mass transport from the water column to the sediment. This study aims to better understand the role of water column OC variability for the fate of pollutants in a near-coastal area. We conducted an in situ sampling campaign in the coastal Baltic Proper during two seasons, summer and autumn. We used polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) as model compounds, as they represent a wide range in physicochemical properties and are ubiquitous in the environment. Freely dissolved, and OC-bound concentrations were studied in the water column and surface sediment. We found stronger sorption of pollutants to suspended particulate matter (SPM) during the summer compared to the autumn (average 0.6 and 0.9 log unit higher particle-water partition coefficients during summer for PAHs and PCBs). Our data suggest that stronger sorption mirrors a compositional change of the OC towards higher contribution of labile OC during the summer, characterized by two times higher fatty acid and 24% higher dicarboxylic acids in SPM during summer. High concentrations of OC in the water column during the autumn resulted in increased SPM-mediated sinking fluxes of pollutants. Our results suggest that future changes in primary production are prone to influence the bioavailability and mobility of pollutants in costal zones, potentially affecting the residence time of these hazardous substances in the circulating marine environment.
海洋环境中有害疏水性污染物的环境归趋受到有机碳（OC）循环的强烈影响。例如，初级生产的季节性会影响水柱中OC的数量和质量，这可能会影响污染物从水柱到沉积物的质量传输。本研究旨在更好地了解水柱中OC变异性对近岸区域污染物归趋的作用。我们在波罗的海沿岸适当区域的夏季和秋季两个季节进行了现场采样活动。我们使用多环芳烃（PAHs）和多氯联苯（PCBs）作为模型化合物，因为它们代表了广泛的物理化学性质，并且在环境中普遍存在。研究了水柱和表层沉积物中自由溶解态以及与OC结合态的浓度。我们发现，与秋季相比，夏季污染物对悬浮颗粒物（SPM）的吸附更强（夏季PAHs和PCBs的颗粒-水分配系数平均比秋季高0.6和0.9个对数单位）。我们的数据表明，更强的吸附反映了夏季OC组成向不稳定OC贡献更高的方向变化，其特征是夏季SPM中脂肪酸含量高出两倍，二羧酸含量高出24%。秋季水柱中高浓度的OC导致污染物通过SPM介导的沉降通量增加。我们的结果表明，未来初级生产的变化可能会影响沿海地区污染物的生物可利用性和迁移性，潜在地影响这些有害物质在循环海洋环境中的停留时间。
