Lead Release to Drinking Water from Galvanized Steel Pipe Coatings
Lead Release to Drinking Water from Galvanized Steel Pipe Coatings
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DOI：
10.1089/ees.2015.0073
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发表时间：
2015-08-01
影响因子：
1.8
通讯作者：
Edwards, Marc A.
中科院分区：
文献类型：
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作者：
Clark, Brandi N.;Masters, Sheldon Vaughn;Edwards, Marc A.
与镀锌钢管有关的饮用水中铅含量升高的问题最近被假设是由于上游铅服务管道在镀锌钢管表面上的铅积累造成的。然而，历史研究表明，通常用于镀锌的锌的等级含有至少0.5%的铅，并且本身可能是铅的重要长期来源，这可能解释了最近与镀锌钢相关的一些铅污染问题。对1950年至2008年间安装的各种镀锌钢管和配件的表面分析表明，原始锌涂层中的铅浓度可以从未检测到接近2%，具体取决于制造商和配件类型。由于镉也存在于许多锌涂层中，但不存在于铅管，含铅焊料或黄铜中，锌浓度与水中铅和镉浓度的相关性被认为是暗示镀锌钢涂层是铅源的可能指纹；从收获的镀锌钢管中进行金属浸出的实验验证了这一方法。使用剖面抽样，在华盛顿特区、普罗维登斯、罗德岛、芝加哥、伊利诺伊州和佛罗里达州的一个城市确定了镀锌钢管作为主要铅源的个别家庭。在某些情况下，该来源的铅含量非常高（100 μ g/L），并且在部分服务管线更换期间，上游安装铜管可能会加剧铅含量。
Problems identified with elevated lead in drinking water associated with galvanized steel pipes were recently hypothesized to result from lead accumulation on galvanized steel pipe surfaces from upstream lead service pipes. However, historical research documents that the grade of zinc typically used for galvanizing contains a minimum of 0.5% lead and can itself be a significant long-term source of lead, which may explain some recent lead contamination problems associated with galvanized steel. Surface analysis of various galvanized steel pipes and fittings installed from 1950 to 2008 demonstrated that the concentration of lead in the original zinc coating can range from nondetect to nearly 2%, dependent on the manufacturer and fitting type. Since cadmium is also present in many zinc coatings, but not in lead pipe, leaded solder, or brass, correlation of zinc concentration to both lead and cadmium concentrations in water was considered as a possible fingerprint implicating the coating on galvanized steel as a lead source; bench-scale tests of metal leaching from harvested galvanized steel pipes were used to validate this approach. Using profile sampling, individual homes with galvanized steel pipes as a primary lead source were identified in Washington, DC, Providence, RI, Chicago, IL, and a city in Florida. In some cases, the levels of lead from this source were very significant (>100 mu g/L) and can be exacerbated by installation of a copper pipe upstream during partial service line replacements.