The Impact of Lead on Humans and the Environment
By Beth Rush
Lead has been among the most commonly used heavy metals worldwide for centuries. Yet, its toxicity to humans and the planet shrouds its usefulness and purpose. The effects of lead exposure on human health and the environment are severe — even trace amounts can wreak havoc on biological and physiological processes.
Here is an overview of lead use in the United States and how people and the planet are most affected.
A Brief History of Lead Use in the U.S.
The U.S. has a long history of lead use, dating back to 1621 when lead mining began in Virginia. Lead became popular because of its low conductivity, flexibility, softness and corrosion resistance. Initially, lead’s primary uses were in paint and tetraethyl lead gasoline. However, it was also commonly found in construction materials, pottery, coins, toys, makeup and cookware.
The health effects of lead exposure were well-documented in the Roman Ages, with reports of gout, paralysis, mental illness and death. From 1925-1927, painters had the highest death rates in the U.S. among any other occupation.
While other countries began banning lead, the U.S.-based Lead Industries Association sent letters and promotional materials to 4,357 water departments, encouraging their continued use of lead pipes. The industry also countered adverse health reports with its own studies on lead exposure to quell public concern.
In 1971, the U.S. Congress finally passed the Lead-Based Paint Poisoning Prevention Act to remove lead from paint products. By 1978, the. U.S. Consumer Product Safety Commission finalized a ban on residential use of lead paint. Nevertheless, the effects of lead exposure on human health and the environment remain a problem today.
The Effects of Lead Exposure on Human Health
Lead doesn’t biodegrade and accumulates in the body over time. Children, in particular, are at high risk of mental and physical developmental delays, while exposed adults are susceptible to severe health concerns, which include:
> Learning challenges
> Irritability
> Weight loss
> Stomach ache and vomiting
> High blood pressure
> Reduced reproductive health
> Miscarriage, stillbirth, premature births and low birth weights
> Cognitive issues and memory loss
> Muscle and joint aches
> Kidney damage
Heavy metals like lead are absorbed through the soft tissues, inhaled or ingested. Often, exposure occurs when drinking contaminated tap water run through lead pipes. Children absorb four to five times more than adults, leaving them especially vulnerable to the effects of lead on human health.
In a study of 244 children from Flint, Michigan — where fallout from lead poisoning was prevalent in 2014 — 25% of the samples had elevated blood lead levels, while 43.9% and 39.3% showed signs of hyperactivity and agitation, respectively. The children with higher lead levels also demonstrated cognitive or behavioral impairments.
Of course, the most severe impact of lead poisoning is all-cause mortality, which is 60% higher than cardiovascular disease mortality globally.
The Effects of Lead Exposure on the Environment
The effects of lead exposure on the environment are as detrimental as they are to humans — some of the impacts even overlap. Here’s how lead poisoning harms the planet and its living things.
Wildlife
Larger mammals become exposed to heavy metals after feeding on animal carcasses killed by lead ammunition or drinking from contaminated water sources. However, avian species are most threatened by lead toxicity. Many birds die two to four weeks after ingesting lead bullet fragments and fishing tackle.
In 2021, the National Park Service found a Great Horned Owl in the West Shore Wildlife Center in Pennsylvania. The owl had demonstrated strange behavior, leading biologists to test it for lead poisoning. While its caretakers were hopeful for its survival, they expressed concern about the long-term health implications.
Plants
Lead accumulation in plants has surprising outcomes for photosynthesis, growth and survival. In fact, one study shows root growth declines by 42% in lead-exposed plants.
This may not be the best news for crops — the same study indicates a 14%–30% decrease in rice seeds. However, plants also aid lead uptake from the earth, resulting in healthier, nutrient-dense soil.
Aquatic and Marine Habitats
Lead leaches from terrestrial sources into waterways and the ocean, creating a toxic aquatic environment and harming freshwater and marine species. Bioaccumulation of lead in fish causes oxidative stress, decreasing their immune function.
Whales and dolphins are also affected by lead exposure. A recent study from Florida Atlantic University found lead and other heavy metals in 90 stranded cetaceans along the Florida and Georgia coastlines. Bodily contamination may impair DNA and cell membranes and increase the risk of heart disease and parasitic infestations.
Microorganisms
Like plants, lead negatively affects microbial communities, including bacteria and fungi. It is highly disruptive to microorganisms and interferes with enzyme functioning and cell growth. Its adverse effects on fungi and bacteria hinder decomposition and nutrient cycling, which are necessary for healthy ecosystems.
Researchers have found lead in over 100 tea gardens in China, making heavy metals more prevalent in commercial tea production. Consumers then purchase and consume tea with trace metals.
Air Quality
Ambient lead pollution — which you inhale — harms the environment and people. Most airborne lead derives from ore and metal processing plants and leaded aircraft fuel. Battery manufacturers, utility companies and waste management facilities are also typical sources.
Nearly 5.13 million excess deaths occur annually worldwide due to ambient air pollution. This statistic could be avoided if the world stopped using fossil fuels.
Lead Removal is Best for both Human and Environmental Health
Fortunately, many countries continue banning lead in manufacturing and consumer products. Removing lead paint and pipes from residences and neighborhoods is a community’s best attempt at staying healthy and safe from its effects. Yet, careful measures for disposal and remediation are equally necessary to preserve the environment.
About the author: Beth Rush is the green wellness editor at Body+Mind, where she covers topics like the power of climate consciousness at all stages of education. You can find Beth on Twitter @bodymindmag. Subscribe to Body+Mind for more posts by Beth!