Health and Safety Programs: Lead in Water


Lead is a toxic substance which accumulates in the body and can cause serious health problems. New laws have been passed because lead is unhealthy for humans, especially children. Small amounts of lead that would not harm an adult can disrupt a child's normal growth and mental development.

Few waters contain naturally high sources of lead. The use of lead solder and other lead-containing materials in connecting household plumbing to public water supplies was banned by EPA as of June 1988. Many older structures still have lead pipe or lead-soldered internal plumbing which may substantially increase the lead content of water at the tap. Regulations controlling the lead content of drinking water coolers in schools went into effect in 1989 (ATSDR, 2000).

Federal and State laws require the Milwaukee Water Works to treat the water to reduce lead. The lead is continuously leached into the water by plumbing materials containing lead, such as lead pipes, lead solder on copper pipes, or brass fixtures. The rate can vary greatly with the variations in natural water quality and the age of the plumbing system. When the water stands motionless for extended periods of time, such as overnight, lead concentrations in the water can sometimes increase greatly. There is no detectable lead in water leaving the Milwaukee treatment plants. (Please refer to the The Milwaukee Water Works Annual Water Quality Report 2006 pdf document, Adobe Acrobat Required for most recent information.)

The allowable amount of lead in drinking water has been lowered from 50 parts per billion (50 ppb) to 15 ppb. Levels slightly above the standard do not necessarily signify a health hazard.

The Water Works has chosen to add phosphate to the water to reduce lead leaching from interior pipe surfaces containing lead. The phosphate forms a very thin coating on interior pipe surfaces to keep lead from dissolving into water. Many other water utilities across the U.S. are taking similar measures. The phosphate is added in the form of phosphoric acid (70 percent H3PO4). Starting in early September 1996, the level will be 3 parts per million (ppm) phosphate. The Water Works anticipates that lead levels will drop below the maximum allowed limit after 1 year, and they hope to subsequently reduce the phosphate dose to 1 ppm (as PO4).

The Department of Physical Plant Services maintains an inventory of water tests conducted for lead at UWM. Analysis for lead in water is performed by Zeeman-platform graphite furnace atomic absorption spectrophotometry. Questions regarding this inventory should be directed to Robert Grieshaber, Industrial Hygiene Specialist, at x4576 or (414) 229-4576.

It is generally recommended that water be run for a few seconds the first time it is used each day, or until it reaches its coldest temperature, before being used for consumption in order to minimize any possible lead contamination.

Questions regarding water quality other than at UWM should be directed to your water utility or to one of the Wisconsin Department of Natural Resources' (DNR) district offices. The Wisconsin DNR website is a good source for general information about lead in Wisconsin's drinking water. Questions pertaining to exposure to lead and its potential effects on your health should be directed to your family physician or your local health department.

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Updated August 8, 2007