Sources and spatial distribution of polycyclic aromatic hydrocarbons in coastal sediments of the Basque Country (Bay of Biscay)

This contribution characterises the sources and distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments of the Basque coast (Bay of Biscay). Different source characterisation approaches (i.e. GIS assisted-chemometrics, PAH diagnostic ratios and analyses of composition profiles) were used in combination to successfully identify the factors determining the origin and distribution of PAHs. Urban/industrial combustion processes were identified as the main PAH source. However, the analysis of PAH composition patterns and diagnostic ratios identified secondary natural and petrogenic PAH sources on small spatial scales. The median ∑18PAH concentration ranged from 66 μg kg⁻¹ (d.w.) to 7021 μg kg⁻¹ (d.w.). The Ibaizabal estuary, which supports most of the anthropogenic pressure in the region (i.e. urban development, industrialisation, commercial and recreational harbours), also showed the highest PAH concentrations. On the shelf, human activities, hydrodynamic conditions and geomorphological features led to spatial differences in the PAH concentrations among sectors: the offshore and west sectors were characterised by higher concentrations, while the lowest values were found in the mid and east sectors. The results enhance the knowledge on PAH-related contamination processes and could be used to support the environmental assessment process required under current European marine legislation.

本研究对巴斯克海岸（比斯开湾）沉积物中的多环芳烃（polycyclic aromatic hydrocarbons，PAHs）的来源与分布特征进行了表征。研究联合采用多种源解析方法，即地理信息系统（Geographic Information System，GIS）辅助化学计量学、PAHs诊断比值法以及组成谱分析，成功明确了决定PAHs来源与分布的关键因素。城市与工业燃烧过程被确定为PAHs的主要来源。然而，通过对PAHs组成模式与诊断比值的分析，在小空间尺度上识别出了次要的天然源及石油成因PAHs来源。18种PAHs总浓度的中位数范围为66 μg·kg⁻¹（干重，d.w.）至7021 μg·kg⁻¹（干重，d.w.）。伊巴伊萨尔河口承受着该区域绝大多数人为活动压力，即城市开发、工业化进程以及商业与休闲港口活动，其PAH浓度也为全区最高。在大陆架区域，人类活动、水动力条件以及地貌特征导致了各区域PAH浓度的空间差异：近海与西部区域的PAH浓度较高，而中部与东部区域的浓度最低。本研究结果深化了对PAHs相关污染过程的认知，可用于支撑当前欧洲海洋法规所要求的环境评估工作。