[Image Credit: Scientific American]
This summer alone, we have seen the West Coast and Mountain West burn, the Midwest flood, and the Gulf pounded by hurricane after hurricane. When most of us think about climate change, it looms as the 21st centuries greatest environmental challenge that only the cutting edge of science can anticipate and counteract.
The bygone problem of lead rarely comes to mind. It seems like a legacy of the 20th century that used leaded gasoline and toxic glazes and paints. But what does it mean when an age-old problem like lead exposure meets a new problem like climate change?
Why worry about lead?
Lead is a neurotoxin. It damages the nervous system, causing neurological disorders, brain damage, and behavioral problems. Lead poisoning generally occurs slowly due to a build-up of lead in the body over months or years. Children under six are especially vulnerable, absorbing five times as much lead as adults, affecting their developing brains.
Most people are exposed to lead by inhaling particles that are the legacy of leaded gasoline exhaust, or by ingesting contaminated dust, water, food, or paint.
But how can a warming climate increase lead poisoning?
In many places, higher temperatures will increase dryness and drought.
Drier soils make dirt dustier. If there is lead in the soil, it becomes more mobile in that dust. These small bits of lead dust get everywhere: in your home, on your food, and even in your eyes and lungs. Research has shown that most of the planet is tainted by the fallout from leaded gasoline. As the climate shifts, communities already contaminated with lead will become even more exposed.
What role do forest fires play in this?
New research shows that forest fires remobilize lead that was already in their environment, which can make lead contamination more widespread.
Fires do this by releasing old lead stored in soils contaminated over 30 years ago with lead particles from leaded gasoline (shown below). Wildfires are so hot they volatilize soils, making the lead airborne, transporting it by the wind along with ash and smoke. The amount of lead in forests is very small, but when compounded over hundreds of thousands of acres, it has a significant effect.
Most shocking, fires can double air lead levels during wildfire seasons within 200 miles of affected areas.
Lead particles contaminate soil, which is reemitted by wildfires [Image Credit: Cynthia Isley]
Unfortunately, flooding does the opposite. Increased flooding heightens the risk of lead poisoning by moving lead out of riverbeds, and into communities.
We will see more long-term flooding under climate change. These long lasting, stagnant floods push metals away from river banks where they were previously contained. Lead then becomes an integral part of the soils left behind, contaminating homes, yards, and parks that were previously lead-free. Increased flooding is especially concerning for those living downstream from lead hot spots, such as abandoned or active mines.
Flooding in the Midwest threatens to spread lead pollution [Image Credit: Jeremy Deaton]
Unfortunately, lead may be important to a clean energy future.
As we use more renewable technologies, we will increase our dependence on batteries. Lead-acid batteries are likely to play a role in supporting renewable technologies. The good news? Lead-acid batteries can be recycled. In fact, almost 99% of lead-acid batteries used in the US since 2007 were recycled. While it is likely that we will eventually transition away from lead-acid batteries, the millions of pounds of lead in these batteries still have the potential to contaminate communities.
New technology also requires lead. The futuristic sounding perovskite, the newest class of solar cells, uses lead. These solar cells need lead to form the complex internal structure that makes this extra-efficient solar power possible. Luckily, this technology only uses 800 mg per solar panel, as opposed to the standard car battery that contains 9,000,000mg (or 20 pounds).
[Image Credit: Science Magazine]
It is clear that it will take a concerted effort to address the climate crisis. This fight will also require continued diligence so that in addressing the most pressing challenge of the 21st century, we do not exacerbate the legacies of one of the worst environmental crises of the 20th century.