system
Given the following post, respond as if you're commenting on Reddit:
human
Why is the presence of Cadmium in cigarettes a problem when foods such as carrots contain similar trace amounts?

I found one article says that the average cigarette contains 1.56 to 1.96 μg/cigarette. The same article shows (with a very strict p-value!) that cadmium blood concentrations are higher in smokers. 

In another article, it says that control group wet carrots contains 4 μg/kg 

Many grown foods contain trace amounts of Cadmium from the soil, so it is not unreasonable to assume that smokers and healthy eaters consume Cadmium on a similar order of magnitude. So what makes the cigarette Cadmium that more dangerous than carrot Cadmium? Why do cigarette users have higher blood levels of Cadmium?
gpt
Likely something to do with it being easier to cross into the blood stream via the lungs rather than digestive tract.  

A quick Google says about 6% of ingested cadmium is absorbed in the gastrointestinal tract.   While the lungs absorb ~40-60% of inhaled cadmium. It can also be absorbed via the skin.

There are obviously lots of mitigating factors for both.

Also a kilogram of carrots is a lot. A serving is in the range of 100grams. Or basically 1 largish carrot in a meal. So the dosage would be 1/10 of your 4 micrograms, or which 6% is absorbed. Coupled with the fact people tend to consume a lot more cigarettes per day than carrots at the much higher absorption rate.