BOSTON — An Adams man was arrested Thursday morning on federal charges that he and a postal worker had been importing, manufacturing and distributing "massive" amounts of synthetic drugs across the country. Daniel Borer, 42, of Adams, and Josephine McLaughlin, 65, of Stoneham, allegedly operated a scheme to import synthetic cannabinoids, also called "spice" or "K2," from China over a five-year period beginning in February 2014, according to an indictment from the U.S. Attorney's Office in New York.