Dow Chemical Co. and DuPont Co. are expecting to get formal objections to their $60 billion merger from European Union regulators as soon as next month, listing potential antitrust concerns with their bid to form the world’s biggest chemical company, according to two people familiar with the investigation. The European Commission in Brussels is poised to send the complaint to the companies in December, according to people who asked not to be named because the process is confidential. It may lay out how the transaction could reduce competition in areas such as crop protection, seeds and certain petrochemicals. The merger is among a trio of pending deals -- including Bayer AG’s agreement to buy Monsanto Co. and China National Chemical Corp.’s agreement to buy Syngenta AG -- that could reshape the agricultural-chemicals industry. EU Competition Commissioner Margrethe Vestager has warned that the deals could leave the sector "quite concentrated."