State Transportation Commissioner George Campbell is not seeking reappointment and plans to work in the private sector by the end of the summer, Governor John Lynch said yesterday. Campbell, whose term expires in December, has been commissioner since May 2008. Lynch said he will nominate someone to fill his term as soon as possible. Lynch said Campbell has been a tremendous leader at the department and helped secure funding to replace Memorial Bridge in Portsmouth. During Campbell’s tenure, the department also implemented high-speed electronic tolls on Interstate 95.