CURRENT EVALUATION OF LIBBY ASBESTOS EXPOSURES

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定为研究者机构。蛭石最初于1881年在蒙大拿州利比东北6英里处被发现。蛭石从20世纪20年代初开采，直到W.R.格雷斯在1990年关闭了工厂。不幸的是，利比矿的蛭石被一系列天然纤维状和石棉状闪石污染，这些闪石出现在整个存款的矿脉中。由于大量开采和加工蛭石及其在利比的使用，利比境内历史悠久的蛭石加工和开采设施周围的许多家庭和地区今天受到石棉污染。此外，在70年的采矿作业中，数以万计的蛭石货物通过铁路从利比运往美国西北部，供应了世界上近70%的蛭石供应。最初的研究是为了确定树皮是否可以作为石棉纤维的储存库。在环境保护局限制矿区内、利比镇内和镇西铁路沿线沿着收集的树皮样本显示出大量的石棉纤维含量。这些调查结果的影响是重大的，因为利比居民在整个冬季都依赖当地收获的木柴为住宅供暖。该COBRE提案由三个具体目标组成，将评估利比山谷中树木作为石棉纤维储存库的作用，以及估算历史暴露量的潜在工具。该项目还将确定利比和主要运输走廊的石棉污染程度（树木内）以及在木柴收获活动期间接触石棉纤维的可能性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Vermiculite was originally discovered six miles northeast of Libby, Montana in 1881. Vermiculite was mined from the early 1920s until W.R. Grace closed the facility in 1990. Unfortunately, vermiculite from the Libby mine was contaminated with a series of naturally-occurring fibrous and asbestiform amphiboles occurring in veins throughout the deposit. Because of the extensive mining and processing of vermiculite and its use in Libby many of the homes and areas surrounding the historical vermiculite processing and mining facilities within Libby are today contaminated with asbestos. In addition, tens of thousands of vermiculite shipments were transported by railroad throughout the northwest United States from Libby during the 70 years of mine operation, in route to supplying nearly 70% of the world¿s supply of vermiculite. Initial studies were done to determine if tree bark could serve as a reservoir for asbestos fibers. Bark samples collected within the EPA restricted mine area, within the town of Libby, and along the railroad lines west of town revealed significant levels of asbestos fiber content. The consequences of these findings are significant, as the inhabitants of Libby are dependent on locally harvested firewood for residential home heating throughout the winter months. This COBRE proposal is composed of three Specific Aims that will evaluate the role of trees in the Libby valley as reservoirs for asbestos fibers and potential tool to approximate historical exposures. This project will also determine the extent of asbestos contamination (within trees) in Libby and major transportation corridors and the potential of asbestos fiber exposures during firewood harvesting activities.