Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain.
Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain.
Sci Total Environ. 2014 Nov 1;497-498:188-199. doi: 10.1016/j.scitotenv.2014.07.093. Epub 2014 Aug 14.
Atmospheric polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) and exist in gas and particle phases, as well as dissolved or suspended in precipitation (fog or rain). While the hydrosphere is the main reservoir for PAHs, the atmosphere serves as the primary route for global transport of PCBs. In this study, fog and rain samples were collected during fourteen events from September 2011 to April 2012 in the Xistral Mountains, a remote range in the NW Iberian Peninsula. PAH compounds [especially of low molecular weight (LMW)] were universally found, but mainly in the fog-water samples. The total PAH concentration in fog-water ranged from non-detected to 216 ng·L(-1) (mean of 45 ng·L(-1)), and was much higher in fall than in winter. Total PAH levels in the rain and fog events varied from non-detected to 1272 and 33 ng·L(-1) for, respectively, LMW and high molecular weight (HMW) PAHs. Diagnostic ratio analysis (LMW PAHs/HMW PAHs) suggested that petroleum combustion was the dominant contributor to PAHs in the area. Total PCB levels in the rain and fog events varied from non-detected to 305 and 91 ng·L(-1) for, respectively, PCBs with 2-3 Cl atoms and 5-10 Cl atoms. PCBs, especially those with 5-10 Cl atoms, were found linked to rain events. The occurrence of the most volatile PCBs, PCBs with 2-3 Cl atoms, is related to wind transport from far away sources, whereas the occurrence of PCBs with 5-10 Cl atoms seems to be related with the increase of its deposition during rainfall at the end of summer and fall. The movement of this fraction of PCBs is facilitated by its binding to air-suspended particles, whose concentrations usually show an increase as the result of a prolonged period of drought in summer.
大气多环芳烃（PAHs）和多氯联苯（PCBs）是持久性有机污染物（POPs），存在于气相和颗粒相，以及溶解或悬浮在降水（雾或雨）中。虽然水圈是 PAHs 的主要储存库，但大气是 PCBs 全球传输的主要途径。在这项研究中，2011 年 9 月至 2012 年 4 月间，在西班牙西北部偏远的西斯特拉山脉（Xistral Mountains）的 14 次事件中采集了雾和雨水样本。普遍发现了 PAH 化合物[特别是低分子量（LMW）]，但主要存在于雾水样本中。雾水中总 PAH 浓度范围为未检出到 216ng·L(-1)（平均值为 45ng·L(-1)），秋季浓度明显高于冬季。雨水和雾水事件中的总 PAH 水平范围为未检出到 1272ng·L(-1)和 33ng·L(-1)，分别为低分子量（LMW）和高分子量（HMW）PAHs。诊断比分析（LMW PAHs/HMW PAHs）表明，该地区的 PAHs 主要来源于石油燃烧。雨水和雾水事件中的总 PCB 水平范围为未检出到 305ng·L(-1)和 91ng·L(-1)，分别为氯原子数为 2-3 的 PCB 和氯原子数为 5-10 的 PCB。发现 PCB，特别是氯原子数为 5-10 的 PCB，与雨水事件有关。最易挥发的氯原子数为 2-3 的 PCB 的出现与来自远距离的风输运有关，而氯原子数为 5-10 的 PCB 的出现似乎与夏季末和秋季降雨期间其沉积量的增加有关。这种 PCBs 馏分的移动是通过其与空气中悬浮颗粒的结合来促进的，悬浮颗粒的浓度通常会随着夏季长时间干旱而增加。
