Lead paint

Lead paint is paintcontaining lead, which was used until the 1970s as a whitepigment. White pigment does not add color, but serves the very important function of increasing opacityand making the paint resistant to UV radiation. For centuries, the primary white pigment in paints was lead white (basic lead carbonate, 2PbCO₃·Pb(OH)₂), one of the oldest pigments known. One problem with lead is that it is extremely toxic, and as lead white ages it turns to lead acetate, which is sweet to taste. This is why children had the tendency to lick or chew on woodwork painted with lead paint.

There is also a red lead, which was once popular as a primer. It is not stable enough to be used much as a pigment.

Lead paint in buildings

One practical way to protect children from lead based paint and lead poisoningis to simply repaint with any modern paint and to repaint any areas where the paint peels or chips in a timely fashion. Children will be unlikely to consume any lead paint because the newly painted surface will not taste sweet. There are many laws regarding lead-based paint remediation, so you may be required to do more than repainting. In preparing the surface for painting, be aware that sanding may create undesirable lead dust; it is preferable to use a liquid sander/degreaser.

Lead test kits are used to test for the presence of lead, but an informed guess can be made if the date of construction of a home is known. Despite mounting evidence of the effects of its use, lead white was widely used in paints in the USA until about 1960, when the danger became too widely known to be ignored. It was rapidly replaced by paint manufacturers and by the time national legislation came into effect in 1978 outlawing its use in the USA, lead was uncommon as a pigment. Homes older than 1960 almost certainly contain lead paint, homes built between 1960 and 1965 are likely to contain lead paint, whilst those built between 1966 and 1978 are not likely to. Homes built after 1978 probably do not contain lead paint.

Lead paint in art

In art, lead white is known as flake white. It is difficult to get the genuine article in many countries, even where other toxic paints (e.g. cadmium colours) are readily available.

Substitutes

Paint manufacturers replaced lead white with a less toxic substitute, titanium white or Titanium dioxidewhich was first used in paints in the 19th century. Titanium Dioxide is safe to use as a food colouring. The titanium white used in most paints today is often coated with silicon or aluminum oxides for better durability.

Zinc white is less opaque than titanium white, and is better for misty glazes and adding aerial perspective.

Some manufacturers supply a lead white hue, which is an attempt to imitate the properties of genuine lead paint without the toxicity.

External links

• Case Studies in Environmental Medicine: Lead Toxicity
• National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
• Medical Knowledge of the Dangers of Lead-Based Paintlt:?vino baltalas

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Lead+paint Wikipedia article Lead paint.