Herrmann R F, Grosser R J, Farrar D, Brobst R B
US Environmental Protection Agency, ORD/NRMRL, 26 W. Martin Luther King Dr., Mail Location 190, Cincinnati, OH 45268.
Pegasus Technical Services, Inc., 46 E. Hollister, Cincinnati, OH 45219.
Aerobiologia (Bologna). 2017 Sep;33(3):417-434. doi: 10.1007/s10453-017-9480-8.
Endotoxins are a component of Gram-negative bacteria cell walls and are known to be present in biosolids. Endotoxins have been shown to be potent stimulators of the innate immune response causing airway irritation and shortness of breath. Class B biosolids are routinely applied to agricultural lands to enhance soil properties and can be used as an alternative to chemical fertilizers. This study investigated the aerosolized endotoxin dispersed during the land application of Class B biosolids on agricultural land and a concrete surface at two sites in Colorado, USA. Aerosolized endotoxin was captured using HiVol samplers fitted with glass fiber filters, polycarbonate filter cassettes (both open and closed) and BioSampler impinger air samplers. Endotoxins were also measured in the biosolids to allow for correlating bulk biosolids concentrations with aerosol emission rates. Endotoxin concentrations in biosolids, impinger solutions and filter extracts were determined using the kinetic amebocyte lysate assay. Aerosolized endotoxin concentration was detected from all sites with levels ranging from 0.5 to 642 EU/m. The four types of sampling apparatus were compared, and the HiVol and open-faced cassette samplers produced higher time-weighted average (TWA) measurements (EU/m) than the impinger and closed cassette samplers. Ambient wind speed was found to be the variable best describing the observed results with optimal wind speed for highest deposition estimated at 5 m s. It is argued that HiVol air samplers are a particularly reliable approach and subsequent analyses relating TWA measurements to wind speed and biosolids characteristics were based on the measurements collected with those samplers.
内毒素是革兰氏阴性菌细胞壁的组成部分，已知存在于生物固体中。内毒素已被证明是先天性免疫反应的强效刺激物，会引起气道刺激和呼吸急促。B类生物固体通常施用于农田以改善土壤性质，并且可以用作化肥的替代品。本研究调查了在美国科罗拉多州两个地点，B类生物固体在农田和混凝土表面土地施用过程中分散的气溶胶化内毒素。使用配备玻璃纤维过滤器、聚碳酸酯过滤盒（开放式和封闭式）和BioSampler冲击式空气采样器的HiVol采样器捕获气溶胶化内毒素。还对生物固体中的内毒素进行了测量，以便将生物固体的总体浓度与气溶胶排放率相关联。使用动力学变形细胞溶解物测定法测定生物固体、冲击式溶液和过滤器提取物中的内毒素浓度。在所有地点都检测到了气溶胶化内毒素浓度，范围为0.5至642 EU/m。对四种采样设备进行了比较，HiVol采样器和开放式盒式采样器产生的时间加权平均（TWA）测量值（EU/m）高于冲击式采样器和封闭式盒式采样器。发现环境风速是最能描述观测结果的变量，估计最高沉积的最佳风速为5 m/s。有人认为，HiVol空气采样器是一种特别可靠的方法，随后将TWA测量值与风速和生物固体特性相关联的分析是基于用这些采样器收集的测量数据。
