Michaud J M, Huntley S L, Sherer R A, Gray M N, Paustenbach D J
McLaren/Hart Environmental Engineering ChemRisk Division, Portland, Maine, USA.
J Expo Anal Environ Epidemiol. 1994 Apr-Jun;4(2):197-227.
A number of fires involving polychlorinated biphenyl (PCB)-containing transformers and capacitors have occurred in the United States. PCB fires generate by-products such as polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzodioxins (PCDDs) and, when the transformer is in a building, contaminate the interior. Considerable concern exists over the potential human health effects associated with exposure by inhabitants to residual levels of PCBs, PCDFs and PCDDs. Office workers, for example, may be exposed to these chlorinated compounds via inhalation of contaminated particulates and vapors, dermal contact with contaminated surfaces, and incidental ingestion of dusts. A wide range of re-entry or cleanup levels have been developed for PCDDs and PCBs to protect workers who re-occupy a building following a PCB fire. Re-entry criteria have been used by property owners and regulatory agencies to determine whether the building is safe to re-occupy or to determine the extent of needed remediation. This paper presents a mass balance approach to deriving risk-based re-entry surface and air criteria for PCBs and PCDD/PCDFs. These criteria were based on a lifetime risk level of 10(-5), recent toxicological data on PCDDs and PCBs, and plausible exposure scenarios. Our analysis suggests that 125 ng/m2 2,3,7,8-TCDD TEQ for surfaces and 10 pg/m3 for air are acceptable. Based on Aroclor 1260, risk-based re-entry criteria for PCBs on surfaces and in air were 750 micrograms/m2 and 0.1 microgram/m3, respectively. In comparison to most previous guidelines, these risk-based criteria are less stringent, but can still be considered conservative. The surface criteria are 5 to up to 125 fold higher than previous guidelines. Air criteria range up to 5 times higher than criteria used at past PCB fire sites. Air concentrations associated with these were modeled and were negligible. For PCBs in air, the NIOSH guideline of 1 microgram/m3 is also appropriate for occupational settings.
美国发生了多起涉及含多氯联苯（PCB）的变压器和电容器的火灾。PCB火灾会产生多氯二苯并呋喃（PCDF）和多氯二苯并二恶英（PCDD）等副产品，并且当变压器位于建筑物内时，会污染室内环境。居民接触残留水平的多氯联苯、多氯二苯并呋喃和多氯二苯并二恶英对人体健康的潜在影响引发了广泛关注。例如，办公室工作人员可能通过吸入受污染的颗粒物和蒸气、皮肤接触受污染的表面以及偶然摄入灰尘而接触到这些含氯化合物。针对多氯二苯并二恶英和多氯联苯，已制定了广泛的重新进入或清理水平标准，以保护在PCB火灾后重新进入建筑物的工人。业主和监管机构已使用重新进入标准来确定建筑物重新入住是否安全，或确定所需修复的程度。本文提出了一种质量平衡方法，用于推导基于风险的多氯联苯和多氯二苯并二恶英/多氯二苯并呋喃重新进入表面和空气标准。这些标准基于10^(-5)的终身风险水平、多氯二苯并二恶英和多氯联苯的最新毒理学数据以及合理的暴露情景。我们的分析表明，表面的125 ng/m² 2,3,7,8 - TCDD毒性当量和空气中的10 pg/m³是可以接受的。基于Aroclor 1260，表面和空气中多氯联苯基于风险的重新进入标准分别为750微克/m²和0.1微克/m³。与大多数先前的指南相比，这些基于风险的标准不太严格，但仍可被视为保守的。表面标准比先前的指南高5至125倍。空气标准比过去PCB火灾现场使用的标准高出5倍。与之相关的空气中浓度经建模后可忽略不计。对于空气中的多氯联苯，美国国家职业安全与健康研究所（NIOSH）1微克/m³的指南也适用于职业环境。
