Friday, 25 February 2011

Will Lead Kill Bob The Builder? - Part I

If you're considering renovating your love nest, painting your old house surfaces, giving a new look to that old set of walls that keep depressing you after work hours, scrap those old surfaces from your grandma's mansion or just treat the dog with a brand new kennel, let me just give you a piece of advise - Think about you and your family!

The ancient paints are no longer acceptable if they've ever been that acceptable at all. In the composition of the paints that covered houses and even cradles back in time, lead could be found in most of them and in very toxic quantities. So, try and imagine how can you give a new look to your house whilst helping the environment, protecting your health, your pet's and your family's health too, just by using non-toxic paint. Or, if you're dealing with very old premises, be attentive to a good set of practices to bear in mind. OK, the greater picture is not an easy conception for those unfamiliar with non-toxic paints or health and safety in the builder's environment, nevertheless, these days one is pretty aware of the dangers associated to old paints and the hazardous effects of, for example, Lead

Before 1970 those old paints were wide spread, but the risks associated to the usage of such dangerous mixtures were ignored for far too long.  Well, high concentrations of lead are still being found in the under-soil vicinity of residential houses as in home gardens because they were way too customary in the builders world. Commonly associated with enamel paint, lead-based paints were traditionally used on window frames, fascias, gutters, bathroom cupboards, interior and exterior walls, doors and other domestic metallic surfaces.

(Image on the left was taken from [4]).

Even though lead in paint is only that harmful if not covered by a metal free paint surface. Or if under friction forces that by scrapping or blasting would cause either flaking or chalking, for example. Small particles of lead-based paint when inhaled represent a great danger to your health. "Pulmonary absorption is efficient, particularly if airborne lead particle diameters are mm, the particles are generally completely absorbed by the alveoli" [1].

Note: Just or the sake of the example, the Australian government revealed that "The recommended amount of lead in domestic paint has declined from 50% before 1965, to 1% in 1965, in 1992 it was reduced to 0.25%, and in 1997 it was further reduced to 0.1%" [2].

Low concentration lead poisoning (10 ug/dl) can affect the central nervous system, blood cells, and cause renal diseases. At high concentrations (approximately 80 ug/dl or more) it is likely to cause convulsions or even induce coma, not to say that death is a possibility. Then in the eventuality of a pregnancy the effects of lead exposure on unborn children, toddlers or even newborns, can be just drastic as it may affect their learning and reading capacities, arrest their mental and physical development, disturb attention span, speech and even cause "language handicaps, lowered IQ, neurological deficits, behavior problems, mental retardation, kidney disease, heart disease, stroke, and death" [1]. And you know why children are more vulnerable to lead exposure than adults? They more easily get their hands on lead-contaminated objects, and ingenuously direct them to their  mouths; but it's not only a behavioral bias, actually children "absorb up to 50% percent of the amount of lead ingested, whereas adults absorb only about 10 to 20% percent" [1]. Transdermal absorption does not represent a great danger if one is in contact with an inorganic form of lead [3].

Would you like a fast scope into lead´s toxikinetics? Well...

- Lead is absorbed into blood plasma: 
             - binds to hemoglobin,  
             - deposits in erythrocytes and soft tissues,
             - in the blood, approximately 95 to 99% of lead stays in red cells,
- Lead crosses membranes such as the blood-brain barrier and the placenta, 
- Lead accumulates in soft and hard tissues,
- Half-life of lead depends on the tissue where it is sequestered (25–40 days in erythrocytes, 40 days in soft tissues, 28 years in bone tissue),
- Bone lead accounts for more than 95 % of the lead burden in adults and 70% of the burden in children,
- Competes with calcium for space in the bone,
- Is excreted unchanged in urine (65–75 %) and in bile (25–30 %).

Source: [1].

If you suspect of lead poisoning,  please consult your physician immediately. In the meanwhile, just take a look at this awesome PDF made available by the Australian Government and entitled - Six Step Guide to Painting Your Home -, from the Aussie Department of the Environment, Water, Heritage and the Arts.

Next week we'll take a look at the second part of this article where I will post information about the benefits of non-toxic paint, the types of non-toxic paint available and some other great tips. Stay tunned!

But before you leave,  the answer to the question Will Lead Kill Bob The Builder is... not if you read The Toxicologist Today.

If you'd like to amend, discuss or help enhance the quality of information provided by this post, please feel free to comment.

[1] - Corrosion Doctors - lead toxicology,, last visited at 25th of February 2011, last update unknown.

[2] - Australian Government, Department of Sustainability, Environment, Water and Communities],, last visited at 25th of February 2011, last updated on the 16-Sep-2009.

[3] - Patočka, J. and Černý, K., (2003).  'Inorganic Lead Toxicology'. Acta Medica (Hradec Kralove), 46(2), pp.65-72.

[4] - The endowment for human development - Improving lifelong health, one pregnancy at a time,, last visited at 25th of February 2011, last update unknown.

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