It’s probably not news to anyone reading this that lead exposure is dangerous, but when most of us think of routes to lead exposure we think of leaded gasoline, paints, drinking water or pencils (although pencils do not, and never did, actually contain lead). But there is another means of exposure that’s causing significant issues for certain populations: lead bullets.
Bullets have traditionally been made from lead for several reasons. The metal is cheap and melts at only 327˚C (621˚F) meaning that it can easily be formed into bullets. It is also very dense, so that lead bullets pack a big punch, so to speak. But lead is also toxic.
After an animal is hunted, even if care is taken to remove the bullet from the carcass, lead contamination of the meat can still occur. Part of the problem comes from the fact that lead bullets often fragment into many small pieces that can disperse throughout the tissue. These lead fragments can then be consumed by the humans or pets who eat this meat.
Several studies have shown that when game is hunted, killed, processed and cooked in standard ways, higher-than-normal levels of lead are found in the meals. This lead contamination especially influences those who rely on game meat as their primary source of food, such as those in Greenland, or Indigenous Canadians, or those using food banks for whom donations from hunters are fairly common.
Even occasional game meat eaters, however, can be affected by lead contamination. Health Canada states that blood lead levels below 5 μg/dL are associated with adverse health effects. One study found that those eating one or fewer meals of gamebird shot with lead bullets per week showed blood lead levels of 7.5 μg/dL, and those eating gamebird meat daily showed blood lead levels of 17 μg/dL. But the effects of lead bullets don’t stop with humans.
As it’s fairly common for hunters to eviscerate their quarry in the field and leave behind the unwanted viscera, scavenging animals can feed upon the discarded remains of humans’ prey and ingest lead in the process. This can lead to many of the same symptoms as human lead exposure.
Another route for exposure is found in birds’ gizzards. To help break down their food birds swallow small rocks and store them in their gizzards. The problem is that to a bird a bullet looks a lot like a small rock.
One Italian study found that those who engaged in hunting showed a blood lead level almost double those who didn’t. This could be from the lead fumes that are released when guns are fired or from handling lead ammunition. The same study did not find any relationship between blood lead levels and consuming game meat, which could point to some regional differences in ammunition manufacturing, hunting or cooking styles influencing the amount of lead that makes it into a final dish of cooked game meat.
Lead exposure can also occur in humans that are shot with lead-based bullets, especially since bullets are sometimes left in a victim’s body, either due to lack of medical attention or complications that would arise from trying to remove them. In some cases, symptoms can occur many years after the gunshot wound. To remedy this, a combination of drugs to help eliminate lead from the body, chelation therapy and surgery to remove the bullet are used.
The good news is that non-lead bullets are becoming more popular. Several places have enacted lead munition bans, and one study showed that non-lead bullets were just as effective for hunting animals as lead bullets. Those who handle bullets in their jobs (such as police or military personnel) would benefit from a switch to non-lead-based munitions, but beyond environmental and health benefits, switching away from lead bullets would also have an economic benefit, as this study shows. As for what could be used instead of lead, there are a few options, the most popular of which seems to be copper, but the most interesting of which is definitely depleted uranium.