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Metal mining in the UK has a long history and the oldest known mines date back almost 4,000 years. Lead mining has been an industry here since the late Iron Age, but serious lead mining didn’t occur until Roman times.
Despite its use being highly regulated due to the risk it poses, the production volume of refined lead in the United Kingdom has increased in the last six years. In 2020, there were 355,300 metric tons of refined lead produced.
In this article, we’ll give you the ins and outs about this metal, including where it’s found, what we use it for, and the health concerns surrounding its use.
What is lead?
Lead is a chemical element that occurs naturally in the Earth’s crust. On the Periodic Table it has the symbol Pb, and its atomic number is 82.
Lead is a heavy metal, putting it in the same bracket as iron, tin and copper. Conversely, aluminium, magnesium and titanium are light metals. Despite being heavy, lead is actually malleable and soft. Its melting point is also relatively low.
Though lead has been mined for thousands of years, it wasn’t until the late 19th century that its toxicity became widely known. As a neurotoxin, lead accumulates in bones and soft tissues and causes health effects.
Where is lead found?
Lead exists all throughout our environment. It’s in the soil, water, air, and even where we live. Lead is usually found in combination with sulphur and is rarely found in its native form. Most lead minerals are light and therefore remain in the Earth’s crust rather than going deeper into the interior.
Historically, lots of our lead exposure has come from human activities like using fossil fuels, lead-based paints, pipes and plumbing materials, batteries, and even cosmetics.
There are many ways in which lead enters our environment. Natural levels of lead in the soil are in the range of 50 to 400 ppm (parts per million). However, lead smelting, mining and refining have all meant there are substantial increases in certain areas, especially near smelting sites or lead mines.
Lead can also be released into the air from other industrial sources.
When lead is present in the soil, it can then move into ground water.
Background lead concentrations don’t exceed 100mg/kg in soil, 0.1 μg/m3 in the atmosphere and 5 μg/L in seawater and freshwater.
What is lead used for?
Lead has a range of uses due to its valuable physical properties. It is used in storage batteries, cables, solder, steel products, ammunition, radiation, and X-ray shielding systems, roofing, computer and electronic circuit boards, optical technology and as a superconductor.
Until 2000, lead was added to ‘four-star’ petrol. In 2000, it was banned by European Regulation. Its ban was due to lead being a cumulative toxin that affected human health. Even now, 22 years on, research by Imperial College London has found that London’s airborne particles are still highly lead-enriched, 40% of which comes from leaded petrol’s legacy.
Until 1969 water pipes were allowed to be made of lead. Homes built before the 1970s in the UK will have been built with lead water pipes and some homes still have these pipes.
Until 1992, lead was also a common ingredient in household paint.
Is lead dangerous?
Lead is considered a cumulative toxicant. This means that you need to be exposed to a lot of it over time for it to be toxic.
The body absorbs lead in the following ways:
- Breathing in lead dust, vapours or fumes. This occurs when lead-containing items are worked or processed and produce lead dust, vapours or fumes.
- Swallowing lead. This occurs when you drink, eat, smoke, or even bite your nails.
When people are exposed to lead, it is stored in their tissues and accumulates over time. It is mainly stored in the bones and will stay there for a long time without making the person ill. Your body does get rid of a small amount of lead when you go to the toilet, but most of it stays in the body where it accumulates.
It is distributed to the bones, kidneys, liver and brain where it causes damage. To test lead exposure, you’d usually have a blood test to measure how much lead is in the blood.
Lead is much more likely to cause harm if you have been exposed to it for a long time, for example if you work in the lead mining industry. It could also be harmful if you’re exposed to large amounts in a short period of time.
The people who are most sensitive to lead exposure are unborn children and children under the age of six.
What are the health effects of lead exposure?
If an individual is exposed to high lead levels over a short period of time whether through food, water, soil, air or dust, they might experience adverse health effects. This might include stomach upsets, changes in mood, poor concentration, hallucinations, headaches, and even kidney or brain damage.
Lower levels of lead exposure over a long time can also cause health problems. This might include low blood pressure, anaemia, and damage to the kidneys, brain and nervous system. It can also affect fertility and reproduction in both males and females.
In the United Kingdom, there are now strict controls on lead exposure in water, food and air in order to minimise health risks.
Health effects of lead exposure in children
Even at lower levels, lead exposure in children can cause the following health effects:
- Learning problems.
- Behavioural problems.
- Lower IQ.
- Slower growth.
- Hearing problems.
In very rare cases, lead poisoning can lead to seizures and coma. It can even be fatal.
Health effects of lead exposure in pregnant women
As we’ve previously mentioned, being exposed to lead over time can lead to accumulations in the body where it is stored primarily in the bones. During a pregnancy, lead (along with calcium) is released from the woman’s bones and can be absorbed by the foetus.
This can lead to the following health problems:
- Premature birth.
- Low birth weight.
- Damage to the baby’s nervous system, kidneys and brain.
- An increased likelihood of behavioural problems and learning difficulties.
When an infant is breastfeeding, they can also be exposed to lead through their mother’s milk.
Who is more at risk of lead exposure?
Working with lead metal
Those at the greatest risk of lead exposure are those who are working with lead through work.
Types of work involving high levels of exposure include:
- Removal of old lead paint (burning or blast removal).
- Stripping lead paint from doors and windows.
- Hot cutting in dismantling and demolition operations.
- Scrap processing – recovering lead from waste and scrap.
- Manufacturing lead-acid batteries.
- Working with lead and lead alloys (including soldering).
- Lead refining, smelting, casting and alloying.
- Processing and manufacturing lead compounds.
- Manufacturing leaded glass.
- Manufacturing (pigmenting) ceramic glazes and colours.
- Recycling lead-containing items (e.g., computer monitors or TVs with CRTs – cathode ray tubes).
Anyone who is exposed to lead, lead compounds, lead dust, lead vapours or lead fumes at work should undergo a risk assessment.
It is the employer’s duty to assess health and safety hazards in the workplace and this includes the health risks of lead exposure. If this risk is deemed ‘significant’ as per the law, there should be measures and precautions in place to lower and control the exposure.
There should be controls including dust and fume extraction, regular maintenance of machinery, washing and changing facilities, and lead-free places to eat and drink. You should also be told of the health risks involved in working with lead and the precautions you will need to take. Finally, you should also be trained to use protective equipment and control measures correctly.
The Health and Safety Executive (HSE) provides a lot of information about working with lead for both employers and workers. Employers need to be aware of The Control of Lead at Work Regulations 2002 (CLAW).
Children’s risk of lead metal exposure
Children have a greater risk of lead exposure compared to adults because their bodies absorb more as they grow. What’s more, their nervous systems and brains are more likely to be damaged by lead exposure.
Younger children and babies are more likely to be exposed to lead because of their lack of awareness and tendency to put things in their mouths that could be contaminated with lead. Playing in the soil and not washing hands, for example, is one way in which young children increase the amount of lead in their system.
Adult risk of lead metal exposure
Adults are also susceptible to lead exposure if they eat or drink foods that contain lead. They can also be exposed if the glasses or dishes contain lead too.
It’s also possible to be exposed to lead by spending time in places with lead-based paint that’s deteriorating. For example, if they’re renovating an older property and stripping paint from old wooden surfaces.
It is a particular concern if a pregnant woman is exposed to lead during pregnancy as her exposure will be passed on to her baby.
How is lead poisoning treated?
Lead shouldn’t be in the human body and so the best thing to do is to prevent exposure to this metal. Once it gets into the human body, it is deposited in the bones, which make it very difficult to remove.
If levels of lead in a person’s body are high enough that they’re causing harm, there are some therapies offered.
Prescription drugs to treat lead poisoning symptoms
If a person has neurological symptoms caused by lead poisoning, they might be given prescription drugs. However, these drugs don’t clear the lead from the person’s body, rather they help manage the symptoms of lead encephalopathy, a condition caused by the lead poisoning.
Lead encephalopathy happens when lead metal has penetrated the brain membranes. Tissues start to break down and cause problems like cerebral oedema (swelling of the brain), loss of muscle control, seizures, delirium and altered mental state.
Here are some drugs used to treat these symptoms:
- Anticonvulsants – For seizure prevention.
- Steroids – To reduce swelling in the brain.
- Mannitol – A diuretic that’s injected to reduce swelling in the brain.
This treatment is used to remove lead (or other toxic metals) from the human body. It works by binding the metals to the drugs so that they come out in stool or urine.
Some chelation drugs are given intravenously while others are taken orally as a pill.
Eliminating sources of lead
Since the main problem with lead is the accumulation of it in the body, the main way to prevent and treat lead poisoning is to prevent further lead exposure.
If a person is identified as having lead poisoning, they will need to be careful to avoid exposure in the future.
Here are some measures to take:
- Isolate sources of lead around the home and get rid of them. This might be lead-based paint and lead pipes in old properties and leaded windows.
- If you do have lead pipes, run a bowl full of water each morning before drinking the water. Boiling the water won’t get rid of the lead.
- If lead is in the soil (or suspected to be), you should make sure you put barriers around those areas and avoid touching the soil. If you do gardening in that area, always wear gloves, and wash your hands and anything that comes into contact with the soil. Any soil that’s come in from the garden should be cleaned up and shoes should not be worn indoors.
- Provide safe sandboxes for children to play in rather than soil.
There are many uses of lead in the United Kingdom. Though it’s no longer used in pipework or as an additive to petrol, it is still used in many industries like the construction industry.
When people are exposed to lead, it accumulates in the body. It is a cumulative toxin, which means that lead poisoning can occur after a long time of minute exposure to the metal. It can also occur if there is a sudden exposure to a lot of lead.
Lead is absorbed into the body and is stored in the bones. You can’t really get rid of it, which means that preventing exposure is the best way to avoid the problems that lead poisoning can cause. The most at risk groups are unborn babies and young children.
Nowadays, there are lots of regulations in the United Kingdom, which mean that a person’s exposure to lead is limited. Employers in the lead industry have a duty of care towards their workers and must abide by certain regulations.
If lead poisoning does occur and it’s severe enough to cause symptoms, there are some treatments available. In general, prescription medication is given to treat the symptoms rather than the poisoning. Chelation therapy can be used to rid the body of excess lead, but this would only be done in extreme cases.