The phrase "a mixture of concern" is correct and usable in written English.
It can be used when describing a combination of feelings or emotions, particularly when expressing worry or apprehension about a situation.
Example: "Her expression revealed a mixture of concern and confusion as she listened to the news."
Alternatives: "a blend of worry" or "a combination of apprehension".
Residents of Sunset Park and Bay Ridge surveyed the streets around them yesterday with a mixture of concern and gratitude.
He kept watching Shiau with a mixture of concern and hope, and brought that same open, sympathetic personality to a duet with Robert M. Valdez, Jr.
His mother stroking his feet, her expression a mixture of concern, sorrow and, eventually, acceptance: This is how her eldest son — a legend in the local Pentecostal serpent-handling community — would die.
WHITE OAK, Md .— A dozen years ago, the closing of the Naval Surface Warfare Center in White Oak, a suburb of Washington, was met with a mixture of concern and hope.
"The situation is very tense because there is a mixture of fear and concern... or worry that this might turn out a nightmare," said Mona Makram-Ebeid, an academic and former MP.
I still remember the look on her face -- a mixture of surprise, concern, pity and fear.
It will be a mixture of genuine concern and curiosity.
As in the work of Danny Lyon, there's no sense of hit-and-run exploitation here, just a mixture of tenderness, concern, and righteous anger.
Newspapers across the globe respond to the "survivors' edition" of French satirical weekly Charlie Hebdo - featuring a cartoon of the Muslim Prophet Muhammad - with a mixture of anger, concern and solidarity.
With my Greek background I have been watching the unfolding drama of Greece with a mixture of confusion, concern and compassion.
The kind of set where the faces of the audiences are a mixture of uncomfortable concern and terror, like when will this young man stop holding us hostage with his fears.
