A highly toxic metal that builds up in the body
Lead (Pb) poses an enormous risk to human health due to its wide distribution in the environment. Although the risk of exposure to acute, high levels of lead has been recently reduced in developed countries, continuous chronic exposure to small quantities of lead is a serious risk all over the world. As revealed in recent cases over the Midwest, exposure to lead is a public health concern in the US as well.
Chronic exposure to lead has irreversible toxicity in several human organs and systems, such as the nervous, blood and bones, reproductive systems, kidney and more. Some people are more susceptible to the adverse health effects caused by lead exposure. Individual sensitivity to lead is set by heritable changes in enzymes metabolizing and secreting this metal, and can be analyzed by a simple genetic test.
Routes of exposure
Lead is a metal that occurs naturally in the earth's crust, but human activity, such as mining, burning fossil fuels and manufacturing has caused it to become more widespread and available.
In the United States, lead used to be common in house paint and gasoline. These products are not produced with lead any longer. However, lead is still present everywhere. It is especially found in older houses, since house paint made before 1978 contains lead.
Household dust can contain lead from lead paint chips or from contaminated soil brought in from outside. Lead particles originating from leaded gasoline or paint settle on soil and can last years. Lead-contaminated soil is still a major problem around highways and in some urban settings. Some soil close to walls of older houses contains lead.
Lead particles may also be released into our tap water by pipes, brass plumbing fixtures and copper pipes soldered with lead. Lead release follows corrosion, most likely to happen when water has a high acid or low mineral content and sits inside pipes for several hours. While homes built before 1986 are the most likely to have lead plumbing, it can be found in newer homes as well. Until two years ago, the legal limit for "lead-free" pipes was up to 8% lead. As of January 1, 2014, all newly installed water faucets, fixtures, pipes and fittings must meet new lead-free requirements, which reduce the amount of lead allowed to 0.25%.
The Environmental Protection Agency says between 10% and 20% of exposure to lead comes from contaminated water. Babies can get between 40% and 60% of their exposure to lead by drinking formula mixed with contaminated water.
Foods stored in pewter, lead crystal glassware or pottery containing lead-based glazing may become contaminated with lead. Imported cans from specialty stores with irregularly soldered side seams may contain high levels of lead.
Most lead poisoning in children results from eating chips of deteriorating lead-based paint. Toys, household items and playground facilities painted before 1978 are major routes of exposure to lead, as well as toys made and painted outside the United States.
Workers can be exposed to lead and can bring it home on their clothes when they work in auto repair, mining, pipe fitting, battery manufacturing, painting, construction and certain other fields.
Lead is a component of tobacco and tobacco smoke. Smokers and second-hand smokers have higher blood lead levels than do people not exposed to cigarettes smoke.
Other sources for lead exposure include:
bullets, curtain weights, old coins, medals and fishing sinkers made of lead
jewelry, pottery, and lead figures
some traditional ethnic or alternative medicines
some cosmetics manufactured abroad
Lead alters the ability of various cell signaling pathways that use calcium. It also promotes the formation of free radicals, and therefor lead is defined as a potential human carcinogen (group 2A) by the International Agency for Research on Cancer (IARC).
Other than promoting cancer, chronic lead exposure can cause many systematic effects such as hypertension, anemia, cognitive deficits, infertility, immune imbalances, delayed development, vitamin D deficiency, and gastrointestinal effects.
Successive rounds of the US National Health and Nutrition Examination Survey (NHANES), both before and after lead reduction measures, have shown associations between blood lead, cardiovascular and cancer deaths, and all-cause mortality.
Young children are most vulnerable to lead, which may cause severe mental and physical impairment.
Children get lead in their bodies by putting the lead containing objects in their mouths. Touching the lead and then putting their fingers in their mouths may also poison them. Lead is more harmful to children because their brains and nervous systems are still developing. Any damage caused by lead poisoning cannot be reversed.
The World Health Organization has identified lead as 1 of 10 chemicals of major public health concern.
The Institute for Health Metrics and Evaluation (IHME) estimated that in 2016 lead exposure accounted for 540,000 deaths and 13.9 million years of healthy life lost (disability-adjusted life years (DALYs)) worldwide due to long-term effects on health. The highest burden was in low- and middle-income countries. IHME also estimated that in 2016, lead exposure accounted for 63.8% of the global burden of idiopathic developmental intellectual disability, 3% of the global burden of ischaemic heart disease and 3.1% of the global burden of stroke.
How to reduce the risk from exposure to lead
Take the following steps to reduce exposure to lead:
Make sure to use lead-free paint in your home.
Keep your home free from dust.
If your home has lead-based paint, check regularly for peeling paint and fix problems promptly. Take precautions when renovating an older home, refinishing old furniture or using lead solder.Try not to sand, which generates dust particles that contain lead.
Avoid or throw away painted toys and canned goods produced outside the US.
Check lead levels in your water supply. Start with its source. Call the municipal water supplier and ask for a copy of their consumer confidence report. Make sure lead levels are below a level of 15 parts per billion (ppb). Many public suppliers put yearly reports online, so you can also find it yourself by typing your ZIP code into the EPA's web site at www.epa.gov/ccr. If your water comes from a private well, look for information from www.epa.gov/privatewells.
The next step is making sure that your house's water pipes do not contaminate the water. You can buy a lead testing kit from home improvement stores to collect testing samples. Follow the instructions and send samples off to a laboratory for analysis. Use a state-certified lab, such as those listed on the EPA's web site. Your local water supplier may help with that, and some will come to your home and test for free.
Whether test results are fine or not, drink or cook only with water that comes out of the tap cold. Water that comes out of the tap warm or hot can contain much higher levels of lead. Boiling this water will not reduce the amount of lead in your water. If the source of contamination is your house's pipes, run the kitchen tap for 1–2 minutes before using the water for drinking, cooking, or preparation of baby formula. This is true especially when the water has been off and sitting in the pipes for more than 6 hours.
You can filter lead out of your water. Note that many popular pitcher-type filters don't meet today's standards for lead reduction, so consider using another filtration system.
When drinking bottled water, research your brand at NSF International, a nonprofit water certification organization.
Consider full replacement of lead water lines by removing the private lines running from the water meter into your home. Contact your water authority for information about replacing water service lines.
Make sure that repairs to copper pipes do not use lead solder. Make sure any contractor doing work in your house is certified in lead control.Flush water lines before using the water for drinking or cooking.
Clean faucets and aerators regularly to remove debris such as metal particles.
Eat a healthy diet. Regular meals and good nutrition might help lower lead absorption. Children especially need enough calcium, vitamin C and iron in their diets to help keep lead from being absorbed.
Wash children’s toys and bottles regularly.Teach your children to wash their hands after playing and before eating.
If you have any questions regarding the safe removal of lead, the following resources can help:
Housing and Urban Development (HUD): 800-RID-LEAD
National Information Center: 800-LEAD-FYI
National Lead Information Center: 800-424-5323