Abstract In this 48-month pilot study, long-term impacts of copper:lead galvanic connections on lead release to water were assessed without confounding differences in pipe exposure prehistory or disturbances arising from cutting lead pipe. Lead release was tracked from three lead service line configurations, including (1) 100% lead, (2) traditional partial replacement with 50% copper upstream of 50% lead, and (3) 50% lead upstream of 50% copper as a function of flow rate, connection types, and sampling methodologies. Elevated lead from galvanic corrosion worsened with time, with 140% more lead release from configurations representing traditional partial replacement configurations at 14 months compared to earlier data in the first 8 months. Even when sampled consistently at moderate flow rate (8 LPM) and collecting all water passing through service lines, conditions representing traditional partial service line configurations were significantly worse (≈40%) when compared to 100% lead pipe. If sampled at a high flow rate (32 LPM) and collecting 2 L samples from service lines, 100% of samples collected from traditional partial replacement configurations exceeded thresholds posing an acute health risk versus a 0% risk for samples from 100% lead pipe. Temporary removal of lead accumulations near Pb:Cu junctions and lead deposits from other downstream plastic pipes reduced risk of partial replacements relative to that observed for 100% lead. When typical brass compression couplings were used to connect prepassivated lead pipes, lead release spiked up to 10 times higher, confirming prior concerns raised at bench and field scale regarding adverse impacts of crevices and service line disturbances on lead release. To quantify semirandom particulate lead release from service lines in future research, whole-house filters have many advantages compared to other approaches.

中文翻译：

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模拟部分铅服务线路更换的长期行为

摘要 在这项为期 48 个月的试点研究中，评估了铜：铅电流连接对铅释放到水中的长期影响，没有混淆史前管道暴露的差异或切割铅管引起的干扰。从三个铅服务线配置中跟踪铅释放，包括 (1) 100% 铅，(2) 传统的部分替换 50% 铅上游的 50% 铜，以及 (3) 50% 铜上游的 50% 铅作为函数流量、连接类型和采样方法。随着时间的推移，电偶腐蚀导致的铅含量升高，与前 8 个月的早期数据相比，代表传统部分更换配置的配置在 14 个月时的铅释放量增加了 140%。即使以中等流速 (8 LPM) 持续采样并收集通过服务管线的所有水，与 100% 铅管相比，代表传统部分服务管线配置的条件也明显更差 (≈40%)。如果以高流速 (32 LPM) 采样并从服务管线收集 2 L 样本，则从传统部分更换配置收集的样本 100% 超过了造成急性健康风险的阈值，而来自 100% 铅管的样本的风险为 0%。与观察到的 100% 铅相比，临时清除 Pb:Cu 连接点附近的铅堆积物和其他下游塑料管道中的铅沉积物降低了部分更换的风险。当典型的黄铜压缩接头用于连接预钝化铅管时，铅释放峰值高达 10 倍，确认先前在工作台和现场规模上提出的关于裂缝和服务管线干扰对铅释放的不利影响的担忧。为了在未来的研究中量化从服务管线中释放的半随机颗粒铅，与其他方法相比，全屋过滤器具有许多优势。