常见饮用水管材上芽孢杆菌孢子采集的表面采样技术评估
Evaluation of surface sampling techniques for collection of Bacillus spores on common drinking water pipe materials.
作者信息
Packard Benjamin H, Kupferle Margaret J
机构信息
National Homeland Security Research Center, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA.
出版信息
J Environ Monit. 2010 Jan;12(1):361-8. doi: 10.1039/b917570a. Epub 2009 Dec 10.
Drinking water utilities may face biological contamination of the distribution system from a natural incident or deliberate contamination. Determining the extent of contamination or the efficacy of decontamination is a challenge, because it may require sampling of the wetted surfaces of distribution infrastructure. This study evaluated two sampling techniques that utilities might use to sample exhumed pipe sections. Polyvinyl chloride (PVC), cement-lined ductile iron, and ductile iron pipe coupons (3 cm x 14 cm) cut from new water main piping were conditioned for three months in dechlorinated Cincinnati, Ohio tap water. Coupons were spiked with Bacillus atrophaeus subsp. globigii, a surrogate for Bacillus anthracis. Brushing and scraping were used to recover the inoculated spores from the coupons. Mean recoveries for all materials ranged from 37 +/- 30% to 43 +/- 20% for brushing vs. 24 +/- 10% to 51 +/- 29% for scraping. On cement-lined pipe, brushing yielded a significantly different recovery than scraping. No differences were seen between brushing and scraping the PVC and iron pipe coupons. Mean brushing and scraping recoveries from PVC coupons were more variable than mean recoveries from cement-lined and iron coupons. Spore retention differed between pipe materials and the presence of established biofilms also had an impact. Conditioned PVC coupons (with established biofilms) had significantly lower spore retention (31 +/- 11%) than conditioned cement-lined coupons (61 +/- 14%) and conditioned iron coupons (71 +/- 8%).
饮用水设施可能会因自然事件或蓄意污染而面临配水系统的生物污染。确定污染程度或去污效果是一项挑战,因为这可能需要对配水基础设施的湿润表面进行采样。本研究评估了两种公用事业公司可用于对挖出的管段进行采样的技术。从新的自来水主管道上切割下来的聚氯乙烯(PVC)、水泥内衬球墨铸铁和球墨铸铁管道试片(3厘米×14厘米)在俄亥俄州辛辛那提市的脱氯自来水中放置三个月进行预处理。试片接种了萎缩芽孢杆菌亚种球形芽孢杆菌,这是炭疽芽孢杆菌的替代物。使用刷子刷和刮的方法从试片上回收接种的孢子。对于所有材料,刷取法的平均回收率在37±30%至43±20%之间,而刮取法的平均回收率在24±10%至51±29%之间。在水泥内衬管道上,刷取法的回收率与刮取法有显著差异。在PVC和铸铁管道试片上,刷取法和刮取法之间没有差异。PVC试片的刷取和刮取平均回收率比水泥内衬和铸铁试片的平均回收率更具变异性。孢子保留率在管材之间存在差异,已形成的生物膜的存在也有影响。经过预处理的PVC试片(有已形成的生物膜)的孢子保留率(31±11%)明显低于经过预处理的水泥内衬试片(61±14%)和铸铁试片(71±8%)。