Guigue Catherine, Tedetti Marc, Dang Duc Huy, Mullot Jean-Ulrich, Garnier Cédric, Goutx Madeleine
Aix Marseille Université, CNRS, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, 13288, Marseille, France.
Aix Marseille Université, CNRS, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, 13288, Marseille, France.
Environ Pollut. 2017 Oct;229:627-638. doi: 10.1016/j.envpol.2017.06.090.
Polycyclic aromatic hydrocarbons (PAHs) and organic matter contents were measured in seawater during resuspension experiments using sediments collected from Toulon Bay (Northwestern Mediterranean Sea, France). The studied sediments were very highly contaminated in PAHs, especially in 4-ring compounds emitted from combustion processes. The sediments used for resuspension experiments were collected at 0-2 cm (diagenetically new organic matter, OM) and 30-32 cm depths (diagenetically transformed OM). They were both mostly composed of fine particles (<63 μm), enriched in organic carbon (8.2 and 6.3%, respectively) and in PAHs (concentration of Σ34 PAHs: 38.2 and 35.7 × 10 ng g, respectively). The resuspension of these sediments led to an increase in concentrations of dissolved Σ34 PAHs, dissolved organic carbon (DOC) and dissolved humic- and tryptophan-like fluorophores in seawater up to 10-, 1.3-, 4.4- and 5.7-fold, respectively. The remobilization in seawater was higher for 4-6 ring PAHs, especially benzo(g,h,i)perylene, whose concentration exceeded the threshold values of the European Water Framework Directive. This noted the potential harmful effects of sediment resuspension on marine biota. From these sediment resuspension experiments, we determined OC-normalized partition coefficients of PAHs between sediment and water (K) and found that during such events, the transfer of PAHs from sediment particles to seawater was lower than that predicted from octanol-water partition coefficients (K) (i.e., measured K > K predicted from K). The results confirmed the sequestration role of sedimentary OC quality and grain size on PAHs; the OM diagenetic state seemed to impact the partition process but in a relatively minor way. Furthermore, differences were observed between 2-4 ring and 5-6 ring PAHs, with the latter displaying a relatively higher mobility towards seawater. These differences may be explained by the distribution of these two PAH pools within different OM moieties, such as humic substances and black carbon.
在使用从法国地中海西北部土伦湾采集的沉积物进行的再悬浮实验中，对海水中的多环芳烃（PAHs）和有机物含量进行了测量。所研究的沉积物受到PAHs的高度污染，尤其是来自燃烧过程排放的四环化合物。用于再悬浮实验的沉积物是在0 - 2厘米深度（成岩作用新形成的有机物，OM）和30 - 32厘米深度（成岩作用转化的OM）采集的。它们主要都由细颗粒（<63微米）组成，富含有机碳（分别为8.2%和6.3%）和PAHs（Σ34 PAHs浓度分别为38.2和35.7×10纳克/克）。这些沉积物的再悬浮导致海水中溶解的Σ34 PAHs、溶解有机碳（DOC）以及溶解的类腐殖质和类色氨酸荧光团的浓度分别增加了高达10倍、1.3倍、4.4倍和5.7倍。海水中4 - 6环PAHs的再迁移率更高，尤其是苯并(g,h,i)苝，其浓度超过了欧洲水框架指令的阈值。这表明沉积物再悬浮对海洋生物群具有潜在的有害影响。通过这些沉积物再悬浮实验，我们确定了沉积物与水之间PAHs的有机碳标准化分配系数（K），并发现在此类事件期间，PAHs从沉积物颗粒向海水的转移低于根据正辛醇 - 水分配系数（K）预测的转移（即，测量得到的K > 根据K预测的K）。结果证实了沉积有机碳质量和粒度对PAHs的固存作用；OM的成岩状态似乎对分配过程有影响，但影响相对较小。此外，在2 - 4环和5 - 6环PAHs之间观察到差异，后者向海水显示出相对较高的迁移率。这些差异可能由这两个PAH库在不同OM部分（如腐殖质和黑碳）中的分布来解释。
