"uncertainties about" is correct and usable in written English.
You can use it to describe an uncertain situation about something. For example: "There are many uncertainties about the effects of the new law."
The goal is to resolve uncertainties about carbon emissions.
There are still lots of uncertainties about that".
United's only uncertainties about Christmas have been logistical.
The decision raises new uncertainties about the case.
Now, uncertainties about the economy and consumer spending abound.
Democratic critics focused today on uncertainties about projected revenues.
He added that uncertainties about Spain had been overdone.
Historical scholarship creates uncertainties about the institution's trustworthiness.
There are also uncertainties about what happens should the hub school lose its outstanding grade.
There are great uncertainties about the likely impact of the emerging Medicare legislation.
Officials say there are too many uncertainties about who would succeed Mr. Arafat, among other questions.
