Lamon Lara, Von Waldow Harald, Macleod Matthew, Scheringer Martin, Marcomini Antonio, Hungerbühler Konrad
CMCC, Euro-Mediterranean Centre for Climate Change, Via Augusto Imperatore 16, 73100 Lecce, Italy.
Environ Sci Technol. 2009 Aug 1;43(15):5818-24. doi: 10.1021/es900438j.
We used the multimedia chemical fate model BETR Global to evaluate changes in the global distribution of two polychlorinated biphenyls, PCB 28 and PCB 153, under the influence of climate change. This was achieved by defining two climate scenarios based on results from a general circulation model, one scenario representing the last twenty years of the 20th century (20CE scenario) and another representing the global climate under the assumption of strong future greenhouse gas emissions (A2 scenario). The two climate scenarios are defined by four groups of environmental parameters: (1) temperature in the planetary boundary layer and the free atmosphere, (2) wind speeds and directions in the atmosphere, (3) current velocities and directions in the surface mixed layer of the oceans, and (4) rate and geographical pattern of precipitation. As a fifth parameter in our scenarios, we considerthe effect of temperature on primary volatilization emissions of PCBs. Comparison of dynamic model results using environmental parameters from the 20CE scenario against historical long-term monitoring data of concentrations of PCB 28 and PCB 153 in air from 16 different sites shows satisfactory agreement between modeled and measured PCBs concentrations. The 20CE scenario and A2 scenario were compared using steady-state calculations and assuming the same source characteristics of PCBs. Temperature differences between the two scenarios is the dominant factor that determines the difference in PCB concentrations in air. The higher temperatures in the A2 scenario drive increased primary and secondary volatilization emissions of PCBs, and enhance transport from temperate regions to the Arctic. The largest relative increase in concentrations of both PCB congeners in air under the A2 scenario occurs in the high Arctic and the remote Pacific Ocean. Generally, higher wind speeds under the A2 scenario result in more efficient intercontinental transport of PCB 28 and PCB 153 compared to the 20CE scenario. Our modeling indicates that in a future impacted by climate change, we can expectincreased volatilization emissions and increased mobility of persistent organic pollutants with properties similar to those of PCBs.
我们使用多媒体化学归宿模型BETR Global来评估气候变化影响下两种多氯联苯（PCB 28和PCB 153）全球分布的变化。这是通过基于一个大气环流模型的结果定义两种气候情景来实现的，一种情景代表20世纪的最后二十年（20CE情景），另一种情景代表在未来温室气体强排放假设下的全球气候（A2情景）。这两种气候情景由四组环境参数定义：（1）行星边界层和自由大气中的温度，（2）大气中的风速和风向，（3）海洋表面混合层中的海流速度和方向，以及（4）降水速率和地理格局。作为我们情景中的第五个参数，我们考虑了温度对多氯联苯一次挥发排放的影响。将使用20CE情景环境参数的动态模型结果与来自16个不同地点的空气中PCB 28和PCB 153浓度的历史长期监测数据进行比较，结果表明模型模拟的多氯联苯浓度与实测浓度之间具有令人满意的一致性。使用稳态计算并假设多氯联苯的源特征相同，对20CE情景和A2情景进行了比较。两种情景之间的温度差异是决定空气中多氯联苯浓度差异的主要因素。A2情景中较高的温度促使多氯联苯一次和二次挥发排放增加，并增强了从温带地区向北极的传输。A2情景下空气中两种多氯联苯同系物浓度相对增加最大的区域出现在高北极地区和偏远的太平洋。一般来说，与20CE情景相比，A2情景下较高的风速导致PCB 28和PCB 153的洲际传输更有效。我们的模型表明，在未来受气候变化影响的情况下，我们可以预期具有与多氯联苯类似性质的持久性有机污染物的挥发排放增加以及流动性增强。
