Chinese customs authorities have blocked the import of 900 kg of "konbu" tangle seaweed from Japan on the grounds that it contains mercury residues that exceed China's safety standards, it was reported Tuesday.
The China News Service said quarantine authorities in Fujian Province have ordered that the cargo be returned to Japan.
According to the news agency, Beijing issued a directive July 2 ordering local quarantine authorities to check mercury levels in Japanese-harvested konbu.
Local quarantine officials were given the choice of either destroying mercury-contaminated konbu or sending it back to Japan.
The China News Service did not report the levels of mercury found in the 23 boxes of konbu imported from Japan.
According to the news report, the seaweed was imported by a Fujian-based food processor. It was reportedly meant to be processed in China and re-exported to Japan.