Extremely high lead level in tap water caused by particulates has attracted increasing attention in recent years. Despite extensive research on the role of particulate Pb in water supply systems with lead service lines, little information is available on the role of particulate Pb in copper (Cu) water distribution systems. In this study, the dissolved, colloidal, and particulate lead and copper concentrations in representative prototype copper pipe water distribution systems with leaded solder joints and brass fixtures are measured. The effects of flow rate and stagnation time on metal fractionation are investigated. For each experimental scenario, all the water that stagnated inside the system is sampled to have a comprehensive understanding of lead contamination. Sampled at flow rates of 200–250 mL/s, the soluble lead and copper make up 60–96 % of the total concentration in the samples after hours of stagnation. More than half of the Pb and Cu particles are larger than 0.8 μm. Higher flow rates result in substantial increases in particulate metal concentrations but have no apparent effect on dissolved metals. The soluble and particulate copper concentrations ($\sim$ 100–250 μg/L) both increase with stagnation time. For the case of Pb, while the particulate concentration increases (up to $\sim$ 40 μg/L after 12 h), the soluble concentration does not change significantly beyond 4 h; this can be attributed to the different solubilities of Pb ($\sim$ 20 μg/L) and Cu ($\sim$ 200 μg/L) in tap water. The results also show that particulates suspended by clean “once through” water (without prior stagnation) can lead to high levels of Pb contamination ($>$ 10 μg/L).

近年来，由颗粒物引起的自来水中铅含量极高引起了越来越多的关注。尽管对含铅供水系统中颗粒状铅的作用进行了广泛的研究，但关于颗粒状铅在铜 (Cu) 配水系统中的作用的信息却很少。在这项研究中，测量了具有含铅焊点和黄铜固定装置的代表性原型铜管配水系统中溶解的、胶体的和颗粒状的铅和铜浓度。研究了流速和停滞时间对金属分馏的影响。对于每个实验场景，都会对系统内停滞的所有水进行采样，以全面了解铅污染情况。以 200–250 mL/s 的流速采样，停滞数小时后，可溶性铅和铜占样品总浓度的 60-96%。超过一半的 Pb 和 Cu 颗粒大于 0.8 μm。较高的流速会导致颗粒金属浓度大幅增加，但对溶解的金属没有明显影响。可溶性铜和颗粒铜浓度（$～$100–250 μg/L) 均随停滞时间而增加。对于 Pb 的情况，当颗粒物浓度增加时（高达$～$40 μg/L 12 h后），可溶浓度超过4 h后无明显变化；这可以归因于 Pb 的不同溶解度（$～$20微克/升）和铜（$～$200μg/L）自来水中。结果还表明，干净的“一次通过”水（没有事先停滞）悬浮的颗粒物可能导致高浓度的铅污染（$>$10微克/升）。