Lead: Why Used? Why Hazardous? What Is Being Done?
Posted on July 12, 2016 by Janice Thompson
Tags, Water/Wastewater
Lead from school drinking fountains and faucets as well as lead paint have been in the news recently. What is lead anyway? Why was it ever used in paint or plumbing fixtures? Why is lead hazardous and what is being done about it?
Lead is a soft metal that is malleable and easy to use in manufacturing. Since it is widespread and easy to mine it has been used for centuries including the manufacturing of water pipes, particularly by the Romans. The Latin word for lead, plumbum, contributed to the English word plumbing. Lead pigment was used in paint to obtain certain colors. More generally, lead’s physical properties increased paint’s durability and meant that a relatively small amount of paint could cover a large area.
Lead is toxic because it disrupts critical bodily functions. Two particular disruptions are especially problematic: 1) Lead can displace zinc in an enzyme that is crucial for the body to produce a part of the hemoglobin molecule that carries oxygen in the blood. 2) It can also block the body’s use of a neurotransmitter that is crucial for learning. Lead is particularly toxic to children, which is why finding lead in plumbing fixtures or paint in schools is especially troubling.
The dangers of lead have been known for a long time. For example, even though the Romans used lead in water pipes, there is historical documentation that they knew that clay pipes were safer. Nevertheless, the advantages of using lead edged out the disadvantages and contributed to industry resistance to change.
The Lead industries Association formed in 1928 and was a key player in fighting warning labels as well as attempts to ban or restrict lead paint. Public health officials, especially those in bigger cities, began to impose restrictions on lead paints in the 1950s but they were frequently overturned by industry lobbying in state capitals. The federal government banned the use of lead in paint in 1978. But in older buildings lead-based paint can still be found and is considered the most significant source of lead exposure in children. Protect Your Family From Lead in Your Home is a good resource for more information.
Exposure to lead in drinking water is also a concern, but recent occurrences of lead in testing by various cities across the country are due to lead solder and brass fixtures inside homes and buildings. Historically, service lines, the small pipes that bring water to homes from the service mains in the street, were sometimes made of lead. The public health community advocated ending the use of lead pipes and though the Lead Industries Association resisted, this practice ended during the 1940’s. But lead service lines had never been used in many western cities, including Portland.
While lead service lines were not used in Portland, short pieces of lead pipes called pigtails or goosenecks were used to connect the galvanized pipe service lines to the mains. Installation of lead pigtails in Portland ended in the 1940s and the Portland Water Bureau (PWB) made a concerted effort in the late 1990s to locate and remove all known pigtails from that earlier era.
Lead solder, used when installing indoor copper pipes, can be a source of lead in Portland homes, generally those constructed between 1970 and 1985. Galvanized pipes are threaded and don’t use solder. Another possible source of lead is that indoor brass plumbing fixtures installed before 2014 can also contain lead with components older than 1985 having a greater likelihood of including lead. A major reason lead continued to be used in brass is because its malleability makes the metal easier to work with during manufacturing and allows brass pipe threads to fit better which helps prevent leaks.
However, manufacturing practices changed when it became clear that solder and brass fixtures in indoor plumbing could result in exposure to lead in drinking water. But replumbing is expensive so these sources of lead remain in some homes. These indoor plumbing components can also be found in public buildings such as schools. It is also possible that these larger buildings may contain additional indoor plumbing features like valves that may include lead.
The possibility of exposure to lead in drinking water can be addressed by running the tap until the water is cold. That indicates that water within indoor plumbing has been flushed out and what is coming out of the tap is fresh water. But the potential for lead exposure in water or paint in Portland and other Oregon communities indicate that not enough testing and follow-up steps have been taken in public buildings and other facilities frequented by children like child care centers. This is why Governor Kate Brown’s call for annual testing of schools for lead as well as radon is important. More information is available at the Oregon Health Authority. CUB will review the results of Portland Public School and City of Portland lead exposure testing. Though our focus will be on possible lead exposure through drinking water, it is good to see that lead paint testing is also underway.
The only way to eliminate lead exposure in water due to indoor plumbing fixtures and lead solder is to update the plumbing but that is obviously a major expense, particularly for schools that face so many demands on limited financial resources. For this reason water utilities take treatment steps to reduce the chances of lead entering drinking water. This treatment, however, can’t eliminate the possibility of lead exposure in drinking water if indoor plumbing features contain lead. This is illustrated by test results in cities across the country as discussed in this USA Today article.
The basic idea, though, is to treat drinking water so it is less corrosive and the potential for lead to leach from solder and brass faucets is reduced. Corrosion control plans for each water utility can vary due to differences in the water source and storage facilities. A helpful story on different options and Portland’s approach was done by OPB News.
The PWB has taken corrosion control treatment steps since 1997 with updates along the way. The most recent water corrosion control study began in 2014. One factor in that timing is the shift to seismically resilient closed reservoirs that may increase the effectiveness of the treatment process compared to the distribution system that included open reservoirs. The final phase of this corrosion control study should be wrapped up next summer. This illustrates the science-based approach taken by the PWB to address water related lead exposure concerns. What CUB will be monitoring is the transparency of the PWB in sharing study results with the public and ensuring strong oversight in developing whatever follow-up steps may be required.
Send questions or suggestions to .(JavaScript must be enabled to view this email address) or (503)227-1984 x24.
To keep up with CUB, like us on Facebook and follow us on Twitter! You can also keep up to date with breaking news by joining our email list today!
12/27/16 | 0 Comments | Lead: Why Used? Why Hazardous? What Is Being Done?