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Abstract：
Flushing tap water is promoted as a low cost approach to reducing water lead exposures. This study evaluated lead reduction when prevailing flush guidelines (30 s⁻2 min) are implemented in a city compliant with lead-associated water regulations (New Orleans, LA, USA). Water samples (n = 1497) collected from a convenience sample of 376 residential sites (2015⁻2017) were analyzed for lead. Samples were collected at (1) first draw (n = 375) and after incremental flushes of (2) 30⁻45 s (n = 375); (3) 2.5⁻3 min (n = 373), and (4) 5.5⁻6 min (n = 218). There was a small but significant increase in water lead after the 30 s flush (vs. first draw lead). There was no significant lead reduction until the 6 min flush (p < 0.05); but of these samples, 52% still had detectable lead (≥1 ppb). Older homes (pre-1950) and low occupancy sites had significantly higher water lead (p < 0.05). Each sample type had health-based standard exceedances in over 50% of sites sampled (max: 58 ppb). While flushing may be an effective short-term approach to remediate high lead, prevailing flush recommendations are an inconsistently effective exposure prevention measure that may inadvertently increase exposures. Public health messages should be modified to ensure appropriate application of flushing, while acknowledging its short-comings and practical limitations.
摘要：
冲洗自来水被推广为减少水铅暴露的低成本方法。本研究评估了在符合铅相关水法规（新奥尔良，洛杉矶,美国）。分析了从376个住宅站点（2015-2017年）的便利样本中收集的水样（n=1497）的铅。在（1）第一次拉伸（n=375）和（2）30→45s（n=375）的增量冲洗后收集样品；（3）2.5→3分钟（n=373），和（4）5.5-6分钟（n=218）。在30s冲洗后，水铅有少量但显著的增加(与首先绘制引线）。直到6分钟冲洗（p<0.05），没有明显的铅减少；但是在这些样品中，52%仍有可检测到的铅(≥1ppb)。较老的家庭（1950年之前）和低占用地点的水铅明显较高（p<0.05）。在超过50％的采样地点中，每种样品类型都具有基于健康的标准超标（最大：58ppb）。虽然冲洗可能是补救高铅的有效短期方法，流行的潮红建议是一种不一致的有效暴露预防措施，可能会无意中增加暴露。应修改公共卫生信息，以确保适当应用冲洗，同时承认其缺点和实际局限性。
