Art Cashin's concern with the second quarter

DuPont's trimming of its earnings forecast is fueling concerns that the second quarter might be weak, veteran trader Art Cashin said Friday on CNBC.

DuPont declined after the chemicals supplier reduced its operating profit outlook for the second quarter and full year. In midday trading Friday, the news dragged on the stock market at-large, too.

"I am concerned, and I've expressed this opinion before that record profit margins are going to begin to revert to the mean," Cashin, director of floor operations at the NYSE for UBS, said on CNBC's "Squawk on the Street." "And unfortunately, this upcoming quarter may begin to show some signs of that,"

By CNBC's Drew Sandholm, with