John Rothwell, president of the Agriculture and Fisheries Committee, was yesterday believed to be considering resignation over the incident.
The island's Department of Agriculture and Fisheries said it had to dispose of the Jersey potatoes when their price fell to 6p a pound. Some were given to tourists and some to the island's pensioners. But without facilities to incinerate the leftovers, officials last month opted for burial.
Last Thursday a 'sweet sickly- smelling' river of fermented potato juice emerged from the 12- acre (4.8 hectare) field above Beauport Bay.
Peter Bastion, chief officer at the department, said: 'The option was to put the potatoes in a shallow layer in the ground so they rotted. What happened was that in one patch the potatoes were buried at a depth that meant they hit the water table. We did not know there was water near the surface.' People were advised not to use the beach on Monday. Scientists will today test the water to see if it is safe.
Gerry Jackson, a chemist at the island's public services department, said: 'The effluent contains the products of fermentation - alcohols, ketones and aldehydes. It is mildly acidic. All these substances are poisonous . . . drinking this stuff wouldn't kill you, but it wouldn't be very pleasant.'
He said there has yet to be a detailed analysis of the flow, but said that the biggest threat was to marine organisms on the beach. The effluent is very 'strong' - it would take 40 times as much oxygen to break it down as it would to break down crude sewage, Mr Jackson said.