Transport Canada has taken notice of new data suggesting Victoria's harbour is the most polluted body of water along B.C.'s coastline.

The department, which has jurisdiction over the harbour, says it will carefully review the information released earlier this week by PollutionTracker, a monitoring program created by conservation group Ocean Wise.

The program collected sediment and mussel samples from 55 coastal locations between 2015 and 2017, including four sites within Victoria's harbour.

It found high levels of contaminants in the harbour including now-banned PCB's, or polychlorinated biphenyl, a highly toxic chemical found in things like coolants and flame retardants.

City of Victoria officials said it wasn't too surprising of a discovery given the harbour's industrial history, which pre-dates most environmental protections.

Transport Canada said it has invested more than $6-million in studies to assess contamination in places like Victoria's harbour, and $60-million to remediate those sites.

Some of the work has already been done, including the removal of 2,170 cubic metres of sediment from the harbour near Laurel Point Park.

"This important work will improve the health of the harbour by removing persistent contaminants, including polychlorinated biphenyls, from the marine food web," Transport Canada said in a statement.

It also remediated 1.7 hectares of land in Rock Bay, removing 290,000 tonnes of contaminated soil and sediment before ownership of the land was transferred to the Esquimalt and Songhees nations in 2016.

Upon releasing the data, Ocean Wise said it's particularly concerned about how contaminants affect endangered populations of southern resident killer whales.

It said the data doesn't necessarily suggest the water is unsafe for humans.