- Advertisement -
Human beings have been prettying up their homes for millennia. Australian aborigines have been getting busy with ochre on cave walls for at least 40,000 years and even the relatively recent Egyptians started decorating their pyramids around 2,500 BC.
Even early on, though, there was a price to pay for making our surroundings more appealing: chemicals in the paint contained substances toxic to both humans and the environment.
It's taken until now to develop paint that sticks to the walls in a pleasing fashion, without the potential to poison your home.
Shedding light on heavy effects
The ingredients used in ordinary paint are a well-kept trade secret. Most paint manufacturers will only divulge the four broad categories of ingredients that make up paint: pigments, solvents, binder and other additives.
Basically, colour comes from the pigment, while the solvent and binder provide the base for the pigment. In enamel or acrylic paints the solvent is a hydrocarbon - derived from fossil fuels - and in water-based paints it is mostly water.
The remaining additives, usually some kind of hydrocarbon, are used for purposes such as controlling drying times and preventing mildew formation.
The minerals and hydrocarbon solvents can be toxic for the environment, and in landfill can contaminate the surrounding earth for decades. One notable nasty is lead.
It's not news that lead is a health and environmental hazard - in fact, humans have known about lead's toxic effects for about 4,000 years.
Lead exposure can affect children's developing nervous systems, leading to speech, language and behavioural problems. In adults, lead exposure can cause high blood pressure, headaches, memory and concentration problems, kidney damage, mood changes, nerve disorders, sleep disturbances, and muscle or joint pain - just to name a few of the symptoms.
So if lead is so noxious, why was it added to paint in the first place? Naturally occurring lead oxide was being used in paints as a white pigment as early as the second century AD. Lead also has the added benefits of speeding up drying times, increasing durability, resisting moisture and freshening the appearance of paint.
For these reasons, Australian house paints still contained as much as 50 per cent lead until 1965. After that time, government regulation restricted lead content to one per cent, but it wasn't until 1997 that the limit for lead concentration was further reduced to 0.1 per cent.