The cleanup of a toxic spill in a Surrey pond could cost tens of thousands of dollars, but it's not just the price tag that has park-goers worried.

Debbie Gregor loves to feed the ducks at Newton Pond, but during a visit last month she noticed something was different.

"There was a sheen. It looked like gasoline floating on top," she recalled Thursday.

But the substance wasn't gasoline. Officials found that someone had dumped as much as 80 litres of hydraulic fluid and other chemicals into the pond.

Stephen Godwin, environment manager for the City of Surrey, said the chemicals found after a local called in the spill suggested someone had been up to something sinister.

"When DCM (dichloromethane) shows up in a sample that usually points to a process making MDMA, which is ecstasy," Godwin said.

The city said there is little to no threat to public health, but the cleanup of the pond and surrounding area is ongoing.

"We used the sucker trucks to manually lift that material off the surface of the soil," he said.

Godwin said the city's water supply is safe, but members of the public still have serious questions about the incident.

Signs around the pond telling park-goers not to pollute indicate that it drains into a fish habitat.

"It could connect to their skin, it could irritate them," BC Wildlife Federation's Neil Fletcher said.

"It might cause long-term damage."

Gregor said the spill's potential impact is upsetting, and wonders who's behind the thoughtless dumping.

"It's terrible for the animals. It's terrible for the people."

The cost of the cleanup has been estimated at between $20,000 and $40,000.

With a report from CTV Vancouver's David Molko