How do I manage possibly lead containing paint flakes?
ANY paint will turn to dust eventually. Removing the large flakes and re-painting is your best bet.

I will say, for a home built in the 70's there is only a very small likelihood that there is any lead paint present. I took the lead paint course, and I'd  have to look the numbers up, but for a home built in the 1800's and early 1900's the likelihood is in 90% range. that number decreases down to the 10% range by the 70's, and lead paint was banned in 1978. I've seen scare tactic quotes that say "Three-quarters of the homes built before 1978 contain some lead-based paint." While this is true it is highly misleading.

Do a web search. There is more info on lead paint that you'll care to look at. Lead has become another buzz word like asbestos, and a lot of people are making a lot of money off it.