The following paper will probably be of interest:

 

Smith et al " Increased Lung Cancer Risks are Similar Whether Arsenic is Ingested or Inhaled"

 

Journal of  Exposure Science aand Environmental Epidemiology.  (2009), 19, pp 343-348

 

They argue that the route makes little difference and it is the adsorbed dose that is important.

 

An interesting paper.

 

regards

 

Albert Prince