What is the lead content in Chinese cash coins?
Could you elaborate on the lead content found in traditional Chinese cash coins? I'm particularly interested in understanding the historical context behind the use of lead in these coins and how it may have varied over time. Was lead a common material for minting coins in ancient China, or was it used more sparingly? Additionally, are there any health concerns associated with the use of lead in these coins, especially for those who may have handled or come into contact with them? Lastly, has the lead content in Chinese cash coins been studied extensively, and if so, what have the findings been?