I didn't mean that they don't uptake it at all, just not enough to be of a concern. If we were growing rice it would be a different story. Cadmium is different though and is taken up much easier.3.1. Role of Plants in Remediation of Arsenic
Plants require an adequate supply of all nutrients, as part of normal growth and development , including arsenic, for their normal physiological and biological functions.
The reasons why plants accumulate and metabolize arsenic are considered in an evolutionary context.
People need arsenic too, but like a tiiiiiiny amount. Some elements are purely toxic to us though, such as mercury.
I wish there was more cannabis specific research, but rest assured, that it can and does absorb heavy metals.
As I said before exposure is the big issue with lead not uptake. Crops exposed to soil (roots and tubers) or closer to the soil (leaf veggies) get high concentrations.