Underground wall to contain PCBs in Montreal

Montreal is building a wall around the former Technoparc site in downtown Montreal to stop PCBs leaking into the St. Lawrence River.
The site, near the Victoria Bridge, was used as a railyard dump since the mid-19th century.
Until now the city has been using booms and sponges to capture the pollutants. Now an underground wall, 160 metres long by 7.5 metres deep will be constructed to contain the toxins.
PCBs were used in electrical equipment, heat exchangers and hydraulic systems until the late 1970s. They are very persistent in the environment and living tissue and are known to harm aquatic ecosystems. It has been illegal to release them into the environment since 1985.