The phrase "a long standing concern" is correct and usable in written English.
It can be used to refer to an issue or problem that has persisted for a significant amount of time.
Example: "The environmental impact of plastic waste has been a long standing concern for activists and policymakers alike."
Alternatives: "a persistent issue" or "an ongoing worry".
A long standing concern with means-tested social welfare payments for low income families with school-age children is that they can reduce incentives to participate in the labour market, potentially leading to long episodes of welfare dependence, depreciation of human capital, and ultimately exacerbating rather than alleviating poverty.
There is a long standing concern that minorities, in particular African Americans and Hispanics, are less willing to participate in clinical research than non-minorities.
Whether vignette studies like ours may be representative of real life practice has been a long standing concern [ 17], although there are some studies in support of their validity [ 18– 218.
A long-standing concern for the environment led me to earmark $600 for Greenpeace.
Several officials spoke about the persistence of the achievement gap, a long-standing concern.
Smith said the ATL had a long-standing concern over children 'meddling in the occult'.
Degradation of excitation profile of selective RF pulses by rapid transverse relaxation has been a long-standing concern.
And among his Latin American group of bishops, America's embargo on Cuba was a long-standing concern.
"There is clearly a long-standing concern about the transatlantic gap in defense spending," Oana Lungescu told reporters in Brussels.
He called the mix of education and enforcement "a simple but effective way to combat a long-standing concern".
The dominance over personal computing technology by the Microsoft OS and the Intel MPU, or 'Wintel', has been a long-standing concern of the government and the marketplace.
