Plumbing lead

Lead has the symbol Pb, from the Latin word plumbum. For thousands of years it s been used to make water pipes (thus the term plumbing. However, it s considered poisonous, and although it can still be found in paint and other materials, it s no longer commonly used for household pipes. Lead is one of the oldest materials known to civilization and has been mined for over 6,000 years. 

Lead is found in nature in several minerals, but never in pure metallic form. Lead forms amphoteric compounds in +2 and +4 valence states. There are over 1,000 compounds of lead known. Most lead salts are only slightly soluble in water, and halides of lead are always anhydrous. 

The main use for lead today is in solder, bullets (it is one of the heaviest stable elements), and car (lead-acid) batteries. Because it s so malleable and soft, yet not prone to rusting (oxidation), it was thought to be excellent for piping until its toxicity was understood. Lead can still be found in some paints because it creates certain colors such as chrome yellow (lead chromate), white (lead sulfate), and red (lead tetroxide). Lead was also widely used as an additive to automotive fuel in the form of tetra-ethyllead, but it is not as common anymore. 

lead is usually purified from an ore called galena (PbS). Lead is so heavy it can be separated from other metals by gravity separation and flotation methods (see Chapter 17 for details on these methods) however, in the oxide form, it s reacted with carbon to get pure metallic lead. 

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Lead makes its way into the water supply primarily through the use of old lead water pipes or lead solder in plumbing. Lead in drinking water can be a significant source of human exposure because of the large amounts of water consumed each day and the ready absorption of lead from water. Lead water pipes are common in older housing and the water distribution systems of older cities. The contribution of lead pipes to blood levels is well documented (ATSDR, 1988). Because soft water is likely to corrode metallic surfaces, lead water pipes are a significant source of lead exposure for people in soft water areas. It also appears that the water supply in the nation s public schools contains lead and thus provides an additional source of lead exposure. 

Its alloys include solder, type metal, and various antifriction metals. Great quantities of lead, both as the metal and as the dioxide, are used in storage batteries. Much metal also goes into cable covering, plumbing, ammunition, and in the manufacture of lead tetraethyl. 

Selenium has also been shown to act synergistically with bismuth to improve the machinabifity of brasses (113). The machining properties are similar to those of the leaded brasses used in plumbing appfications. Environmental concerns arising from the leaching of lead brasses necessitates a replacement of the lead. 

Corrosion. Copper and selected copper aHoys perform admirably in many hostile environments. Copper aHoys with the appropriate corrosion resistance characteristics are recommended for atmospheric exposure (architectural and builder s hardware), for use in fresh water supply (plumbing lines and fittings), in marine appHcations (desalination equipment and biofouling avoidance), for industrial and chemical plant equipment (heat exchangers and condensers), and for electrical/electronic appHcations (coimectors and semiconductor package lead-frames) (30) (see Packaging). 

The main interest in polybut-1 -ene is in its use as a piping material, where the ability to use a lower wall thickness for a given pressure requirement than necessary with other polyolefins, together with the low density, can lead in some cases to economic use. The principal application is for small-bore cold and hot water piping (up to 95°C) for domestic plumbing. Current world-wide sales are of the order of 16-20X10 tonnes per annum. 

Lead zero TT Action Level = 0.015 Infants and children Delays in physical or mental develoj Adults Kidney problems high blood pressure Corrosion of hfflisehold plumbing systems erosion of natural deposits... 

Blei, n. lead, -abgang, m. lead dross, lead scoria, -ablagerung,/. lead deposit, -acetat, n. lead acetate, -ader, /. lead vein, -anti-monerz, n., -antimonglanz, m. zinkenite. -arbeit, /. lead smelting plumbing, -arse-nat, n. lead arsenate, -arsenglanz, m. sarto-rite. -arsenik, m. lead arsenate lead arsenide, -art, /. kind or variety of lead. 

Senk-blei, n. plumb bob plumb hne sounding lead, -boden, m. (Brewing) false bottom, strainer, -bombe, /. depth bomb, depth charge. 

Some elements come in and out of fashion, so to speak. Sixty years ago, elemental silicon was a chemical curiosity. Today, ultrapure silicon has become the basis for the multibillion-dollar semiconductor industry. Lead, on the other hand, is an element moving in the other direction. A generation ago it was widely used to make paint pigments, plumbing connections, and gasoline additives. Today, because of the toxicity of lead compounds, all of these applications have been banned in the United States. 

The history of lead is almost as ancient as that of tin. In Roman times, lead was formed into pipes that were used for water supplies (hence our word plumbing, derived from the same Latin word, plumbum, that gives us the s Tnbol Pb). Lead is a component of pewter and also was used as a glaze on drinking vessels. White lead, ... 

Lead levels ranging between 10 and 30 pg/L can be found in drinking water from households, schools, and office buildings as a result of plumbing corrosion and subsequent leaching of lead. The combination of corrosive water and lead pipes or lead-soldered joints in either the distribution system or individual houses can create localized zones of high lead concentrations that exceed 500 pg/L (EPA 1989f). 

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