Nova Scotians are being warned not to harvest shellfish including clams, mussels, whelks, oysters and bay scallops from most coastal areas of the province.

Environment Canada said heavy rains earlier in the week washed contaminants into the water, posing a health hazard to humans.

'It's not a precautionary measure. We're quite certain that the areas would be contaminated.'—Chris Roberts, Environment Canada

In Cape Breton, the closed areas include the Bras d'Or Lakes shoreline in both Inverness

and Richmond Counties. Shellfish harvesting

is also prohibited along the Victoria County shoreline from Cape North to Cape Smokey and the Atlantic coastline of Richmond County.

On mainland Nova Scotia, the shorelines of Guysborough, Yarmouth and Halifax Counties are closed.

The harvesting ban could last up to two weeks.

"It's not a precautionary measure. We're quite certain that the areas would be contaminated," said Chris Roberts, head of Marine Water Quality Monitoring with Environment Canada.

"Over the past 30 years we've collected water quality information, water quality samples, throughout the Maritimes. It's very clear that in certain levels you do get elevated levels of bacteriological contamination that occurs with rainfall."

Roberts said people should check with Department of Fisheries and Oceans before harvesting shellfish to make sure the area is safe.