Filtering respiratory protection devices (FRPD) are mandatory for workers to wear in the Portuguese waste-sorting industry. Previous results regarding microbial contamination found on FRPD interior layer raised the question of whether microbial contamination from the exhalation valve would also have cytotoxicity effects. Since the FRPD exhalation valves are very close to workers’ nose and mouth, they represent a source of exposure to bioburden by inhalation. This study aimed to evaluate the cytotoxicity of the microbial contamination present in the FRPD exhalation valves. For this purpose, the cytotoxicity effects were determined through the MTT assay in two different cell lines (human A549 epithelial lung cells, and swine kidney cells) and compared with previous results obtained with FRPD interior layers. The contamination present in the FRPD exhalation valves presented some cytotoxicity on epithelial lung cells, suggesting the inhalation route as a potential route of exposure through the use of FRPD in the waste-sorting industry. Half-maximal (50%) inhibitory concentration (IC50) values were lower for FRPD interior layer than exhalation valves in lung cells, with overall cytotoxicity lower in exhalation valves when compared to interior layer (z = −4.455, p = 0.000). Higher bacterial counts in TSA were correlated with lower IC50 values, thus, higher cytotoxicity effect in lung cells. No statistically significant differences were detected among different workplaces.

在葡萄牙垃圾分类行业，工人必须佩戴过滤式呼吸保护装置 (FRPD)。先前关于在 FRPD 内层发现的微生物污染的结果提出了一个问题，即来自呼气阀的微生物污染是否也会具有细胞毒性效应。由于 FRPD 呼气阀非常靠近工人的鼻子和嘴巴，它们代表了通过吸入接触到生物负载的来源。本研究旨在评估 FRPD 呼气阀中存在的微生物污染的细胞毒性。为此，通过 MTT 测定法在两种不同的细胞系（人 A549 上皮肺细胞和猪肾细胞）中测定细胞毒性作用，并与以前用 FRPD 内层获得的结果进行比较。FRPD 呼气阀中存在的污染对上皮肺细胞具有一定的细胞毒性，表明吸入途径是废物分类行业使用 FRPD 的潜在暴露途径。FRPD 内层的半最大 (50%) 抑制浓度 (IC50) 值低于肺细胞中的呼气阀，与内层相比，呼气阀的整体细胞毒性较低 (z = -4.455, p = 0.000)。TSA 中较高的细菌计数与较低的 IC50 值相关，因此，肺细胞中的细胞毒性作用较高。不同工作场所之间没有发现统计学上的显着差异。FRPD 内层的半最大 (50%) 抑制浓度 (IC50) 值低于肺细胞中的呼气阀，与内层相比，呼气阀的整体细胞毒性较低 (z = -4.455, p = 0.000)。TSA 中较高的细菌计数与较低的 IC50 值相关，因此对肺细胞的细胞毒性作用较高。不同工作场所之间没有发现统计学上的显着差异。FRPD 内层的半最大 (50%) 抑制浓度 (IC50) 值低于肺细胞中的呼气阀，与内层相比，呼气阀的整体细胞毒性较低 (z = -4.455, p = 0.000)。TSA 中较高的细菌计数与较低的 IC50 值相关，因此，肺细胞中的细胞毒性作用较高。不同工作场所之间没有发现统计学上的显着差异。