How dangerous is lead drinking water?

Lead is a heavy metal with large reserves in the Earth's crust. Due to the wide distribution, easy extraction and processing properties, lead has been accessible and commonly used by people thousands of years ago. However, unlike some other metals, lead has absolutely no physiological role in the human body. That's why the harms caused by lead exposure are countless.

Lead poisoning has been recorded since Roman times, Greece and ancient China. So far, this toxic metal has been restricted to use. Even so, there are still about 143,000 lead-related deaths every year, mostly concentrated in developing countries.

Not except that you and your family are drinking lead-contaminated water without even knowing it.

People often think that only workers who work in lead-related industries like metallurgy, gasoline, paint, ammunition . are at risk of exposure. However, did you know lead poisoning can come from water?

This is especially dangerous because you cannot see, taste or smell to detect lead in water. Therefore, it is not except that you and your family are drinking lead-free water without even knowing it.

How does lead get into water?

The widespread use of lead decades ago left many of the pathways for this heavy metal into drinking water, from groundwater to bottled water. However, there is an important milestone, since the 1970s, lead has been banned for use in many industries.

From this marker, causes of lead exposure can be classified. For example, if you entered a house built before 1978, when lead-containing paint was not banned, you would be exposed. In 2014, when Flint City, Michigan, United States switched to an old water supply system, this immediately triggered the lead-water crisis.

President Obama then had to declare a federal emergency. Flint's old water purification and piping systems have exposed thousands of children to lead at levels 20 times greater than what is allowed.

A lead pipe can be corroded, spreading lead or lead ions into water in different ways. First, water is able to dissolve a small amount of lead when it flows in pipes. If the pipe is made of lead combined with copper, it will form a Galvanic battery system. In particular, lead acts as anode, copper is cathode. Water, like an electrolyte solution, will lead to more aggressive corrosion.

Factors such as dissolved oxygen, pH and mineral content in water also influence the dispersion of lead into the water. For example, oxygen in water combines with lead, forming lead hydroxide Pb (OH) 2, which is a precipitate compound, which prevents the dispersion of lead into water, but is only effective in the pH range from 7 to 10.

In the case of water pipes at Flint, the original water supply contains phosphate-based materials that create an insoluble mineral layer inside the tube wall. It has anti-corrosion effect on the inner lead layer. However, when exchanging water, the mineral layer quickly dissolves, revealing a metal surface that will easily be oxidized by agents such as oxygen and chlorine, causing lead ions to spread and contaminate the water.

Pipelines with lead and copper form a Galvanic battery, in which lead will corrode.

Studies show that lead pipe is more corrosive if the water inside it is soft, contains little calcium and magnesium ions or has a low pH. In addition, groundwater can be contaminated with lead for a long time as a result of the metal industry.

Bottled drinking water can be sourced from the old production line, with the same mechanism if there are pipes, machine parts containing lead. For another reason, lead can be released from plastic or metal bottles.

How does lead-contaminated water affect health?

Lead in water can be exposed through skin-to-skin contact, but it is still mostly ingested, if you drink lead-contaminated water. Children will absorb about 40-50% of the water soluble lead into the body. Meanwhile, adults only absorb about 3-10%. This is why children are the main danger if exposed to lead.

When it enters the body, lead is stored mainly in blood, soft tissue and bone. It will survive in the blood for a few weeks, a few months in soft tissues and annually in bones. Lead in bones, teeth, hair and nails is tightly bound and is less harmful.

For adults, 94% of the lead absorbed is deposited in the bones and teeth. However, for children only about 70%. This fact further indicates that lead-infected children have a much higher health risk than adults.

In children, even low levels of lead exposure can cause damage to the central nervous system, peripheral, disability, growth retardation, hearing impairment and hematological cell function. Children growing up may have learning behavior problems, low IQ, hyperactivity . In rare cases, lead poisoning can cause seizures, coma and lead to death.

For children, being exposed to low levels of lead can also have sequelae for the rest of their lives.

For pregnant women, lead accumulates in the body competing with calcium in bones. It can cross the placental barrier, exposing the baby. As a result, the fetus will grow and the mother is at risk of preterm birth.

In adults, lead exposure has also been reported to have cardiovascular effects such as hypertension. It also causes impaired kidney function and adversely affects reproduction. However, if detected early, treatment for lead infection may not leave a sequelae in adults.

Conversely, for children, low levels of lead can also leave sequelae of cognitive impairment for the rest of their lives. The Flint crisis cost an estimated $ 28 million in emergency allocations, focusing on tests for children suspected to have lead. If expanded to subjects under 21, Michigan may need about $ 600 million.

How much lead in water is dangerous?

According to the US Environmental Protection Agency, the level of lead in drinking water must be limited to less than 0.015 mg / L. Many experts also point out that the dangerous figure must be even lower than that, below 0.01 mg / L.

Human intoxication is diagnosed by testing the amount of lead in the blood. For adults the normal result is below 0.2 mg / L. Insignificant higher levels are considered not serious. A person is counted as poisoning and must be treated when his or her blood lead level is higher than 0.6 mg / L.

For children, blood lead levels are limited lower. Normal results will be below 0.05 mg / L. Lead levels of 0.1 to 0.25 mg / L were possibly associated with impaired neurological function. Levels above 0.25 mg / L will cause headaches, irritability and more serious neurological problems.

The indicated treatment begins at 0.45 mg / L. 0.5-0.7 mg / L levels are counted as moderately toxic. Above 0.7 mg / L is calculated as severe poisoning and may cause convulsions, death.

The level of lead in drinking water must be limited to less than 0.015 mg / L.

Back to the concentration of lead in water, how does it relate to these dangerous levels? Research shows that blood lead levels rise by about 0.1 mg / L, with 0.05 mg lead levels in 1 liter of water consumed.

Thus, just by drinking water with lead concentration of 0.05 mg / L, children can be exposed to lead with blood levels twice as normal. Compared with the above data, this level of lead is sufficient to cause a decrease in the child's neurological function. However, the number must be higher in order to cause harm to adults.

How to prevent lead-contaminated water?

As stated, lead-contaminated water is undetectable in the usual way. If you suspect you are using a source of lead-contaminated water, you should order water samples tested at scientific institutions. Sources of water suspected to be at high risk of lead contamination if using metal piping systems such as lead, brass, copper solder, old-generation water supply systems.

Beware of old pipes like these, which have caused the lead-water crisis in Flint, USA.

If the result of your lead test in water exceeds 0.015 mg / L, you should notify your water utility for treatment. Water samples should be checked from the water inlet and the last inlet to eliminate lead from being released into your own piping.

Also note that some bottled beverages can also be contaminated with lead, through cans, bottles or from the manufacturing process. Lead can also come from other products such as gasoline, paint, toys, plastic, batteries . if manufacturers use outdated technologies.

Therefore, to ensure good health, you should request a commitment from the manufacturer, before buying any product that is at risk of lead. If you are concerned about the health of your children or yourself, perform blood lead testing at health facilities.

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