Lead Poisoning: Impacts and Sources

Lead is often used in ceramics and cookware as a glaze, protecting the earthenware from corrosion over time. Leaded glazes provide a lustrous waterproof coating and have been traditional in many cultures. Originally brought to the Americas from Spain in the mid-1800s, leaded glazes have been in continuous use in traditional pottery in Mexico and elsewhere. However, using lead glaze presents a very large risk, especially when utensils are used in the preparation of food. Lead can easily leach from ceramic glazes and into food when fired at low temperature. Wood-fired kilns used by most artisanal potters often do not reach the fusing/sintering temperatures necessary to vitrify lead glazes to prevent lead from leaching into food.

Additionally, many of the potters work in and around their homes, exposing their families, and particularly young children, to lead dust. Acidic foods, such as lime and tomato juice, and high-heat cooking also cause lead to leach more readily from the pottery and cookware.

Lead-contaminated metal cookware (pots, pans, woks, pressure cookers, and similar products) is an under-researched lead exposure source that Pure Earth has found in countries across the globe and that may contribute substantially to chronic exposure. Recent research suggests that lead in inexpensive, locally made aluminum cookware is widespread and may release lead into food. 

Spices, such as turmeric, marigold, and others, are adulterated with lead chromate to enhance their color and weight in many countries. These lead-adulterated spices can contribute significantly to elevated blood lead levels among children and adults. The practice of adding lead-based pigments to enhance the color and weight of spices is occurring in several countries. Some of these contaminated spices find their way into kitchens worldwide through the global food supply chain. 

Traditional cosmetics like kajal, surma, and kohl, commonly used in South Asia, the Middle East, and North Africa, often contain lead sulfide, which can significantly increase blood lead levels. The U.S. FDA warns against using these products due to the elevated risk of lead exposure, as some samples have been found to contain toxic levels of lead. Pure Earth’s Rapid Market Screening Project also revealed lead contamination in cosmetics, advocating for stricter regulations to minimize exposure, particularly in products like eyeliner and lipstick, which can result in cumulative lead ingestion.

An important cause of lead exposure is lead paint, which is unregulated in 55% of countries globally. Even though the harmful effects of lead in paint have been documented since at least the 1890s, 106 countries do not have lead paint regulations. Even in countries that have taken steps to ban leaded paint, such as the United States and many European nations, lead-based paint is a continuing health hazard due to the deterioration of existing lead paint on walls and surfaces.

Lead is added to paint to increase drying capacity and durability, as it resists moisture and helps prevent corrosion. Children can be poisoned if they chew on surfaces coated with lead-based paint, such as windowsills and door edges. It is especially dangerous to children because it tastes sweet, and when lead paint peels and cracks over time, it creates flakes and dust which children can ingest. Toys painted with lead-based paints also can taste sweet, which further encourages children to mouth them.

Explore more resources from the Global Lead Paint Alliance, Lead Exposure Elimination Project, IPEN, and the US Environmental Protection Agency.

Lead in drinking water, most commonly from decaying or corroding pipes and fixtures or from solder that connects pipes, continues to be a risk. Installation of lead pipes in the United States on a major scale began in the late 1800s, particularly in the larger cities. By 1900, more than 70% of cities with populations greater than 30,000 used lead water lines. Although lead was more expensive than iron (the material of choice until that time), lead pipes had two significant advantages over iron ones: they lasted much longer than iron (about 35 years compared with 16) and, because lead is more malleable, the pipes could be more easily bent around existing structures. The degree to which lead dissolves into water depends on the temperature, pH, and time that water has been in touch with corroding lead pipes.

Lead is a naturally occurring element found in a variety of forms in the Earth’s crust. The mining and extraction of lead ore is crude and often leads to community and industrial contamination. Historically, exposure to lead was extremely high amongst those working in lead mines, especially where adequate protection for workers was not provided or available.

Metallic lead from ULAB recycling is easily melted and cast into ingots. However, the lead oxide paste scraped from ULB plates needs more complicated processing. The process of converting a metal oxide to raw metal is called “smelting” and it involves mixing the powdered lead oxide with a carbon source (usually charcoal) and “cooking” the mixture.  The exothermic reaction results in molten metallic lead, which is scooped up and molded into ingots. Smelting can take place in enormous industrial kettles or small cast iron skillets. Lead contamination occurs when the dry lead oxide powder is mishandled. Lead smelting facilities are often found adjacent to lead mining sites. 

Lead can be found in soil and dust, especially where activity relating to lead operations has taken place, such as industrial operations, smelting or ULAB recycling. Areas where pesticides containing lead arsenate was used and land where coal ash has been dumped often are contaminated with lead residue. High levels of leaded soil can be found where leaded paint used on houses has chipped, flaked and peeled into the soil. Moreover, while lead is no longer used in gasoline, years of deposits from its use, as well as industrial sources, may still contaminate soil. Artificial turf playing fields may also contain potentially unhealthy levels of lead dust, especially older ones that are exposed to weather and are more likely disintegrate.

E-waste (or ‘electronic waste’) refers to anything with a plug, electric cord or battery that has been used and disposed as waste. E-waste includes computers, televisions and mobile phones, among other electronic devices.  It is hazardous, complex, and expensive to safely recycle or dispose of e-waste.

Approximately 80% of e-waste is shipped to low- and middle income countries, often illegally, where thousands of informal workers, often including children, pick through, dismantle and/or burn the e-waste to obtain valuable metals and materials. These practices expose them to toxic substances, including, but not limited to, lead. The poorest residents are usually the most affected in these informal recycling industries, which typically have limited workplace protections. Moreover, children living near these sites are forced to breathe air that is toxic as a result of the burning of e-waste and dust that has been swept up in the wind, to eat food that may have been grown in contaminated soil, and to drink water which is potentially full of harmful chemicals from e-waste sites.

There are many professions in which workers can be exposed to dangerous levels of lead. Moreover, there is potential for the worker to extend contamination beyond the workplace and into areas where families and children live and play. Parents whose occupations involve working with lead often bring contaminated dust home on their clothes, hair, hands and shoes, thus inadvertently exposing their children to the toxic element. Historically, exposure to lead was extremely high amongst those working in lead mines, especially where adequate protection for workers was not provided or available.