Click on a circle in the chart to view Sham immigration records. You can find out when most of the Sham families immigrated to the United States. You can focus your search to immigration records dating from that era. Immigration records can tell you an ancestor's name, ship name, port of departure, port of arrival and destination.
Probably, however...: As my colleague dr. Pappas mentions, marijuana is almost always tested in urine rather than blood, so someone would almost certainly pass a blood test but is more likely to face a urine test.
Urine testing is able to detect marijuana usage more effectively than a blood test beyond a week. If you suspect someone is abusing marijuana it may be best to use an alternative drug testing method, such as urine testing or hair follicle testing. How Long Does Marijuana Stay in Hair? Hair follicle testing is often considered one of the most accurate methods of drug testing.