Tsukiji fish market
There is a risk of contamination on artificial islands with landfill and reclaimed land if there was industry that spilled (toxic) chemicals into the ground. For example, the artificial island Toyosu was once occupied by a Tokyo gas factory. Toxic substances were discovered in the soil and groundwater at Toyosu. The Tokyo Metropolitan Government spent an additional 3.8 billion yen ($33.5 million) to pump out groundwater by digging hundreds of wells. In June 2017, plans to move the Tsukiji fish market were restarted but delayed in July to the autumn of 2018. After the new site was declared safe following a cleanup operation, Toyosu Market was opened.