Lead

Lead

Lead is a heavy metal that is easily extracted from its ores and has therefore been used since ancient times. Lead is soft, dense, malleable and has a low melting point. Lead is used extensively in the production of lead-acid batteries in solder and alloys. Compounds of lead have historically been added to petrol where it acts as an antiknock and lubricating agent. Due to the neurotoxic properties of lead, its use as a petrol additive has now been banned in most countries. Lead’s high density and corrosion resistance make it ideal for a number of applications, it has been used for the manufacture of bullets since the middle ages and is commonly used for ballast or weighting. In 1993 six hundred tonnes of lead were used to weight the base of the leaning tower of Pisa.

Lead is used extensively throughout the construction industry. Its malleability makes it an ideal material for roofing and it is commonly used in cladding, flashing and guttering applications. Lead’s high density makes it an ideal shielding material for use in protection from radiation such as X-rays. Contra to popular belief lead has never been used to manufacture pencils.

Agency Limit (ppb)
UK - DEFRA 10
US - EPA 15
EU - EEA 10
WHO 10

Lead and our health

Lead is highly toxic and dangerous to life affecting every organ and system in the body. Lead is capable of binding tightly to the active sites of many enzymes and thus rendering them inactive. Lead can also displace essential metals within the body such as calcium, iron and zinc. By mimicking calcium lead is known to cross the blood-brain barrier. It is known to interfere with the development of children’s brains.

Studies have shown that high exposure to lead can cause miscarriages in pregnant women. Chronic high level exposure has been shown to reduce fertility of males.

Lead in our drinking water

Lead contamination of drinking water is rarely present as a result of dissolution from natural sources. The primary source of lead contamination is from the corrosion of plumbing systems containing lead pipes. In the UK lead pipes were widely used before the 1970 when they were banned due to health concerns. Homes built after the 1970s are unlikely to have lead pipes but lead contamination can still occur from the use of leaded solder. The amount of lead that leaches into drinking water depends on a number of factors including pH, temperature, the hardness of the water and the time the water has been standing in lead pipes.

In 2014 the water supply to the residents of Flint, Michigan, USA was changed and the water company failed to correctly treat the water. Many of the house’s water supplies were connected with lead service lines which resulted in lead contamination of the drinking water supply. In 2015 an investigation lead by Virginia tech found that at least a quarter of homes in Flint had levels of lead above the US-EPA limit of 15ppb with some homes having contamination levels as high as 13,200ppb.

Tests

Lead in your drinking water can be detected by the following tests.

Removing Lead

Lead can be reduced or removed from your drinking water using the following methods.

  • Reverse Osmosis
  • Cation Exchange Columns
  • Activated Carbon Filters

Further reading