Literally first link is the link that is under discussion here. It has no data about lead levels, and is what I pointed out.
Second link, your own quoted bit of it says "may be"
Third link,
Models were adjusted for percent of a population employed in construction, agriculture, forestry, fishing, hunting, and mining, income distribution, and potential lead paint exposure, which were found to be the primary predictors of elevated pediatric blood lead levels.
And
Firearm use and ownership remains one of the least researched areas in the public health sphere. While the risks of childhood lead exposure are widely understood, including the mechanisms of firearm-related lead exposure and tracking, to date no research has extensively examined it in children and on the community level. Our findings indicate a dire need for continued research on the risks associated with firearm use, ownership, and lead exposure.
Which follows into the 4th study, that is just a repeat of the 3rd link...
Starts off with:
Lead exposure is a significant public health concern and children are at the greatest risk given their exposure to take-home lead. Firearm-related take-home lead exposure may be one of the greatest influences on elevated pediatric blood lead levels.
Again may be...why? Because it's very difficult to correlate the two, because...as the study states:
Pediatric blood lead levels were positively correlated with licensure, poverty, and certain occupations and negatively correlated with lead in water and police or firefighter employment.
Most people who live or work in clean environments and have money usually are not firearm owners. Aka a large portion of firearm owners are not rich. So they have occupations that are more likely to be around lead exposure, and they're more likely to live in older parts of a city or area that has more lead exposure via the soil like I pointed out.
I suggest you read your own links before you call out my reading comprehension. None of these links actively provide evidence that firearms are a major source of lead exposure...as I stated above, they should be looking at the military more than someone shooting for a whooping 30mins a month.
More research is required to substantiate this relationship on the individual-level and into prevention/mitigation.
I agree study link number 4....