Allegations that Metro Vancouver garbage in the Cache Creek regional landfill – which takes trash from across the Lower Mainland, including Abbotsford – is leaching toxins into the local environment have been largely refuted by an independent review commissioned by the provincial government.

The environmental consulting firm AMEC Earth and Environmental found there’s no evidence of leachate from the landfill contaminating the Bonaparte River or area drinking wells.

It found natural minerals like calcite and gypsum were responsible for higher levels of several chemicals in groundwater and said higher chloride levels are likely due to the use of road salt and dust suppressant on area roads.

AMEC called for further investigation of methane gas escaping from the landfill.

Landfill operator Wastech said it’s aware of the outstanding issues and is addressing them.

The review by AMEC was ordered in response to a critical report released in March by International EcoGen Inc. that claimed elevated levels of contaminants in surface and ground water likely came from the landfill.

The North Vancouver consulting firm had been hired by the Nlaka’pamux Nation Tribal Council, which opposes landfill expansion in the area.

The preliminary findings had raised concerns that the landfill liner may have failed and that a plume of toxins was escaping.

“The interpretations and strong conclusions presented... regarding the potential impacts to groundwater due to the site are not supported by their data,” the AMEC report says.

Although there’s no evidence the liner has failed generally, the report notes there may be small tears and punctures in the liner that happened when it was installed.

“Potential exists for greater leachate flow through the lining system than the original design assumptions,” it said, noting the 20-year-old liner does not meet modern design standards.

AMEC recommended Wastech find ways to minimize the creation of leachate inside the landfill.

Wastech should stop disposing of water from washing trucks in the landfill, it said.

And the report says and should consider altering how it disposes of fly ash, which comes from Metro’s waste-to-energy plant in Burnaby and contains more serious contaminants like dioxins and furans.

Landfill officials say they’re happy with the findings.

“The AMEC results confirm two decades of independent monitoring and analysis of the ground water quality below the landfill,” said Wastech general manager Russ Black.

Wastech is seeking permission to expand the landfill, which is currently slated to close in 2010.

Expansion there would be one of a number of possible options to landfill Metro waste instead of building new waste incinerators.

The Cache Creek landfill currently takes 500,000 tonnes of trash per year.