I grew up in Broken Hill NSW; a silver, lead and zinc mining town that had the largest and richest ore body of its type in the world, and where the mining giant BHP originated. Many years ago the smelters were located here but have long since been moved to

other towns. The mining and smelting of lead has left varying degrees of lead dust in almost every house ceiling and wall cavity, every back yard soil, and in most rainwater tanks. On windy days, this dust can be blown around and get into just about everything.

Now that the history lesson is over, let’s have a basic science lesson. Heavy metals are metals that are high on the chemical elements chart, such as lead and mercury. Lead can be found in many things, including ammunition, metal alloys, soldering, old leaded petrol, old paints, car batteries, industrial pollution, and even just in the soil as a natural occurring element. Mercury can be found in certain types of fish, mercury thermometers, as a preservative in some vaccines and other medications (in such tiny quantities as to not cause a problem unless a person's mercury levels are already too high), industrial pollution, and in the soil as a naturally occurring element.

NB: I’m going to shorten this advice by just providing a link to further information about mercury in fish, as it is a topic unto itself.

Now, for a basic medical lesson: In small quantities, heavy metals just exist like all other elements and don't do a great deal of harm. However, when absorbed in high quantities by humans, these heavy metals replace iron in the blood stream and can cause irreversible damage to the body and brain. It can get into the blood, bone marrow, and just about every living cell. It can take a lifetime for the body to purge itself of these heavy metals if it absorbs too much. Heavy metal poisoning has been linked to irreversible intelligence loss, learning difficulties, delayed development, anemia, constipation, hyperactivity, behavioural problems, headaches and migraines, and some other autistic-like symptoms (NB: heavy metal poisoning does not cause autism). Heavy metals can be passed through the placenta from mother to baby during pregnancy and the effects on the developing fetus can be severe, and may not show for some time after the baby is born and the baby’s developmental milestones are delayed. Symptoms of high levels of heavy metals in the body can be hard to recognise. A simple blood test can detect the amount and types of heavy metals present in the blood.

You don’t have to be living in a mining or smelting town to suffer from heavy metal poisoning. As I said in the second paragraph, there are many ways to become exposed to these metals. A person living in the western suburbs of Sydney is just as likely to suffer from it as a child in Broken Hill due to industrial pollution over the years. And even though leaded petrol hasn’t been around in most places for a long time, when it was in regular use, you have to question how much lead ended up in the atmosphere that is now resting in the cavity of your ceiling or in your back yard. If you live in an old house, was that first coat of paint that’s been buried under numerous redecorating efforts old enough to contain lead? And how much mercury have you absorbed from the fish you eat?

There’s no point panicking about it though. It’s just a fact of life that we should be aware of and learn to deal with. If you aren’t living in an area where it is likely to be a serious problem, and you don’t so things that might expose you to such a risk – such as a lot of soldering – and you live in a newer house or one where the paint isn’t flaking, then relax, you’ll be fine. However, if you are living in a high industrial area, a mining town, near a smelter, or even just in a place where the wind is going to be blowing the pollutants from these types of places nearby over your house on a regular basis, or if you have a job or hobby that might expose you to these elements, or an older house with flaking paint, you might want to pay some attention. You also might want to pay attention to the article I have linked if you eat a lot of fish.

Children are far more susceptible to heavy metal poisoning than adults, and the effects on children are far worse. Unlike an adult, children crawl around on the ground, stick everything in their mouths, and their brain and body hasn’t fully developed and thus the effects can be far more devastating, as their development can be severely hampered. There are ways to protect your children from these elements if you are living in a high-risk environment. Most of them are common-sense things we all do anyway. Things that you can do are:

• Provide ground cover over bare soil, such as fresh uncontaminated soil, mulch, bark chips, lawn, pebbles, etc.
• Replace sand in sandpits annually and cover swimming pools when not in use.
• Keep pets and shoes outside.
• Avoid creating dust, wipe away dust with a damp cloth, and mop floors instead of sweep them.
• Use an allergy and dust free vacuum cleaner, if you don’t have and can’t afford one, limit vacuuming to no more than once a week.
• Avoid using leaf blowers and other dust-creating machines when possible.
• Wipe clean children’s toys and anything that collects dust regularly.
• Teach children to wash their hands regularly, especially after playing outside, with pets, and before touching or eating food.
• Discourage children from sticking hands and non-food items in their mouth.
• Don’t let them eat anything they have dropped on the floor or ground.
• Do not drink rainwater from a tank unless the tank has been tested for contaminants, and get rainwater tanks that are used for drinking tested annually.
• Take care when renovating to not create dust, make sure to use appropriate protective wear such as dust masks.
• Repair peeling paint.
• Seal up cracks in walls and ceilings.
• Clean or replace air-conditioner filters annually.
• Keep doors and windows closed on windy dusty days.
• Wash fruits and vegetables before eating them.
• If you work a job or have a hobby that exposes you to heavy metals, take appropriate precautions, such as appropriate clothing, masks, work in well-ventilated areas, etc.
• Pay attention to what types of fish you eat and how much you consume.
• A diet high in iron, zinc, and calcium can reduce the body’s ability to absorb heavy metals.
• Fatty foods can increase the body’s ability to absorb heavy metals.
   

In small amounts, these heavy metals won't do much harm. They are naturally occurring elements, and we all have a little bit of everything in us already. It's having high levels of them in your blood that is a concern. The more of it there is, the more harm it can do. If you are concerned about exposure to heavy metals, you can ask your doctor for a blood test to check if your levels are too high. Unfortunately there is no real cure for heavy metal poinsoning, and the effects of it can be life-long. This is one case where prevention is better than cure.