The Washington Post will suspend a veteran foreign correspondent after the newspaper found that a story he wrote contained several unattributed sentences from a science journal.

The article, which appeared on the front page of Sunday’s newspaper and online the day before, was written by William Booth, a longtime Post reporter and chief of the paper’s Mexico bureau. It described the expansion of the Panama Canal to accommodate a new generation of super-size cargo ships and the race among U.S. ports to keep up with the bigger vessels.

The newspaper said the story contained four sentences that were similar to a science-journal article written last month by Andrea M. Hricko, a professor of preventive medicine at the University of Southern California.

Booth will remain with the paper but will be suspended for three months as a result of the episode, according to one person with direct knowledge of the matter. Editors declined to comment, saying it is a private personnel matter.

Hricko challenged Booth’s article in a letter to the newspaper on Tuesday, claiming it contained wording similar to what she had written in December for Environmental Health Perspectives, a monthly journal. Hricko detailed five instances in Booth’s article that she said mimicked her wording without credit.

The Post determined that four of Booth’s sentences were “copied in whole or in substantial part” from Hricko’s work.

The problematic sentences are similar but not exact duplicates. Booth changed the phrasing in some of them and added clauses and new information to others.

Hricko, for example, wrote that “Georgia’s Port of Savannah has gotten the go-ahead to dredge its channel, which will cost more than $650 million.” Booth wrote, “After years of review, and amid fear for wetlands and endangered species, Georgia’s Port of Savannah has finally gotten the go-ahead to dredge its channel, which will cost more than $650 million.”

The Post and other mainstream news organizations prohibit their journalists from taking published material from another source without permission or attribution.

The newspaper has published a corrected version of Booth’s story online and appended an editor’s note apologizing to Hricko. It also said it would take “severe and appropriate action” to discipline Booth but did not give details.

Booth said in a statement that he made “an inadvertent and sloppy mistake” that he described as “unintentional.” Nevertheless, he called it “a very serious lapse” and apologized to Hricko and the journal. He also apologized to his editor and colleagues “and especially to the readers of the Washington Post for my failure to measure up. I hope to regain your trust. I will work hard to do that.”

Hricko, in an interview, said she was satisfied with the outcome. “Several editors [at The Post] have been in touch with me since this started and they’ve handled it all with great integrity and responsibility,” she said.