Lead can enter our body through air, soil, water and food. The presence of lead in drinking water comes from several sources. Lead contamination can happen before and after water treatment system.

The source of lead contamination before water treatment system can be from:

  • Surface run-off water from garbage dumps e.g.

    • batteries are thrown into garbage dump
    • gasoline leak (leaded type)
    • lead-based epoxy paint
    • lead grinding
  • Industrial waste into river

The source of lead contamination after water treatment system can be from age or condition of pipes, plumbing materials, faucets and other fixtures. It covers from the municipal water distribution system to building plumbing systems:

  • lead pipe
  • pipe with galvanized steel

  • copper water pipes, joined by using high lead content solder (tin/lead

  • brass valves and fitting (contains 2-8% lead)

The lead can leach into the water system through corrosion, increased by the condition below:

  • pH of the water (more if pH lower that 6.5)
  • concentration of inorganic carbonate, orthophosphate, chlorine and silicate
  • temperature (more on higher temperature)
  • nature of pipe surface.

When pH was less than 6.5, lead leached into the water was 45% higher than at pH 8.0. Another study shows that 3 mg/L of lead was leached into high purity water within 30 minutes of contact and the value keep increasing with the contact time. The first study was using lead pipe and the second study was using soldered copper pipes.

Another study was carried out on lead pipes during colder months and summer months. When the water was warmer, a higher lead level was obtained from water pipes samples.

What is the save limit? And how would it affect our health?

Our body can remove lead through urine. However the rate is very low i.e. 0.5 [micro]mol/L. Access lead that enter our body is accumulated in our tissues.

Lead that presence in our body can be measured from our blood. However, it is just a measurement of the current exposure to lead.

According to The Centers for Disease Control and Prevention (CDC), blood lead level above 10[micro]g/dL of blood is a concern. However, lead below that level can also cause damage in children development. Blood lead level of 20-40 [micro]g/dL causes decreases in neuro-cognitive function. And blood lead level below 20[micro]g/dL can cause hypertension in adults.

Therefore, presence of lead in the body should be zero especially in young children.
According to the Public Health Report May-June 2005, presence of lead in drinking water contributes 14-20% of total lead exposure in the United States.

Possible effects of lead poisoning in children and adults:

  • death (children)
  • comas (children)
  • nervous system damage
  • blood disorder
  • brain damage
  • kidney damage
  • permanent loss of IQ of 5 to 7 IQ points (children)
  • shortened attention span (children)
  • anti-social behaviours (children)
  • reduce learning abilities (children)
  • slowed growth (children)
  • mental retardation (children)
  • physical retardation (children)
  • hearing problem (children)
  • delayed puberty in girls
  • cardiovascular system (heart)
  • immune system
  • weakness in fingers, wrists or ankles
  • increase in blood pressure
  • anemia
  • danger to fetus in pregnant woman
  • male reproductive system (DNA damage by lead) – studies using rat.

Effects of lead poisoning in children are more serious than adults. This is because children absorb lead easier than adults, even at a low level of lead in drinking water.

So, what is the permitted level / guideline of lead allowed in drinking water?

  • The Australian Drinking Water Guidelines : 0.01 mg/dL (100ppb)
  • Health Canada : 10 [micro]g/L (10ppb)
  • Lead and Copper Rule (LCR) published by U.S. Environmental Protection Agency (U.S. EPA) : 0.015 mg/L (15ppb).

NSF Standards for Drinking Water Treatment Units / Components

  • NSF/ANSI Standard 53: Drinking Water Treatment Units – Health Effects

    • The requirements & test procedures to reduce lead in drinking water to the level of 15[micro]g/L (15ppb).
  • NSF/ANSI Standard 61: Drinking Water System Components-Health Effects

    • contains procedures for evaluating piping that have contact with drinking water such as municipal water distribution systems and building plumbing systems. The total allowable concentration (TAC) of lead is 15[micro]g/L (15ppb) for lead extraction test. However, the TAC is to be reduced to 5[micro]g/L (5ppb) and the implementation date is 1 July 2012.