Department of Geography and Program in Planning, University of Toronto, Canada.
Environ Sci Technol. 2010 Apr 15;44(8):2777-83. doi: 10.1021/es9012036.
PCBs, used to manage risks from the flammability of dielectric fluids and to increase the durability of elastic sealants, had declining environmental concentrations after legislation banning new production was passed during the 1970s and 1980s in Europe and North America. To answer why PCB temporal trends are now nearly stable and if current policies will further reduce concentrations and our exposure, we estimated PCB stocks in Toronto, Canada (population of approximately 2.5 million) of 437 (282-796) tonnes, of which 97 and 3% are in closed sources and building sealants, respectively. The greatest geographic density of PCBs is downtown, specifically in commercial, electricity-intensive skyscrapers. An unknown stock is within now-buried landfills and other waste-handling facilities as well as diffuse sources such as electrical wiring and paints. Using the Multimedia Urban Model, we estimated city-wide emissions of approximately 0.14-1.4 mg m(-2) y(-1) or 35-350 mg capita(-1) y(-1) of SigmaPCB(70), which is approximately 0.01-0.3% annually of total documented stocks. Canada, as one of 159 signatories of the Stockholm Convention and the 35 parties that have reported progress toward environmentally sound management of their PCB inventories by 2028, has passed national legislation with a timetable of inventory reductions. It is unclear whether this legislation will successfully reduce concentrations and exposures, however the analysis should inform our management of other contaminants.
多氯联苯（PCBs）曾被用于控制电介质流体的可燃性风险，并提高弹性密封剂的耐用性。在 20 世纪 70 年代和 80 年代，欧洲和北美的立法禁止新生产之后，其环境浓度呈下降趋势。为了解释为什么 PCBs 的时间趋势现在几乎稳定，以及当前的政策是否会进一步降低浓度和我们的暴露水平，我们估计了加拿大安大略省多伦多市（人口约 250 万）的 437（282-796）吨 PCB 库存，其中 97%和 3%分别存在于封闭源和建筑密封剂中。PCBs 的最大地理密度位于市中心，特别是在商业密集、电力密集的摩天大楼中。未知的库存存在于现在被掩埋的垃圾填埋场和其他废物处理设施以及电气布线和油漆等弥散源中。使用多媒体城市模型，我们估计全市范围内的排放量约为 0.14-1.4 毫克/平方米/年或 35-350 毫克/人/年的 SigmaPCB（70），这大约是总记录库存的 0.01-0.3%。加拿大是 159 个斯德哥尔摩公约签署国之一，也是 35 个报告了 2028 年实现其 PCB 库存环境无害化管理进展情况的缔约方之一，已经通过了国家立法，规定了库存减少的时间表。目前尚不清楚这项立法是否会成功降低浓度和暴露水平，但这项分析应该为我们管理其他污染物提供信息。
