CN Rail and the Ministry of the Environment say they are getting ready to test the waters of Silver Creek after nine tanker cars derailed on Saturday, with three of them tipping over and dumping coal into the water.

CN says it's working with the ministry on testing but that weather conditions prevented them from getting started earlier.

A ministry spokesperson, however, told CBC News that it didn't carry out testing the day of the spill because it was more focused on clean-up efforts and the immediate risks to the environment.

Some Burnaby residents are taking matters into their own hands, unwilling to wait. Alan James is collecting water samples for testing by a private firm, and he says the coal dump is a real concern.

"The creek was black — as black as the portion going into the Brunette River."

Fish biologist Mark Pearson is worried about the impact on sensitive fish habitat. 

"Between the salmon, the Nooksack Dace and the Western Painted Turtles which are in the habitat behind me, this is a real biological jewel in the Lower Mainland."

The Nooksack Dace has been declared endangered under Canada's Species at Risk Act.

Silver Creek lift from CBC Video

Biologists describe Silver Creek as an environmentally sensitive jewel home to at least one endangered species of fish. (CBC)

While the ministry says it plans to conduct testing of the water, some say that's too little too late. Otto Langer, a former senior biologist with Fisheries and Oceans for 32 years, says the water should have been tested right away if the results are to mean anything:

"If you don't go out there and do it immediately, you've lost 90 percent of the purpose of testing."

Langer says the city of Burnaby was lucky it was coal. It could have been a lot worse.

"CN and CP want to put more bitumen on our rail tracks, and as we've seen it can be a real problem."

A CN Rail investigation has put the blame for the Saturday derailment on heavy rain, which led to the washout of a beaver dam.

With files from the CBC's Farrah Merali