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 Limulus amebocyte lysate assay. Aerosolized endotoxin concentration was detected from all sites with levels ranging from 0.5 to 642 EU/m3. The four types of sampling apparatus were compared, and the HiVol and open-faced cassette samplers produced higher time-weighted average (TWA) measurements (EU/m3) 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−1. 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.

中文翻译：

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在 B 类生物固体的土地应用过程中测量内毒素雾化的实地研究

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免疫反应的有效刺激剂，会导致气道刺激和呼吸急促。B 类生物固体通常用于农田以增强土壤特性，并可用作化学肥料的替代品。本研究调查了在美国科罗拉多州的两个地点的农业用地和混凝土表面上施用 B 类生物固体的过程中分散的雾化内毒素。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 撞击式空气采样器的 HiVol 采样器捕获气溶胶内毒素。还测量了生物固体中的内毒素，以将大量生物固体浓度与气溶胶排放率相关联。使用动力学鲎变形细胞裂解物测定法测定生物固体、撞击溶液和过滤提取物中的内毒素浓度。从所有地点都检测到气溶胶内毒素浓度，水平范围为 0.5 至 642 EU/m3。对四种类型的采样装置进行了比较，发现 HiVol 和开放式盒式采样器比撞击式和封闭式盒式采样器产生更高的时间加权平均值 (TWA) 测量值 (EU/m3)。发现环境风速是最能描述观测结果的变量，在 5 m s-1 处估计最高沉积的最佳风速。