ENVIRONMENT bosses say they cannot rule out a "significant"
ammonia pollution from a large chicken shed set to house 28,000 birds.
Other upgrades are needed to avoid sewage runoff into the Willamette during heavy rain, and to meet more stringent regulations on
ammonia pollution and the temperature of water discharged into the river, officials said.
More than 80pc of
ammonia pollution is produced by agriculture - mainly livestock manure but also from nitrogen fertilisers.
Manure mountains and fertilisers are responsible for up to 60 per cent of nitrate pollution, 43 per cent of phosphate pollution and up to 90 per cent of
ammonia pollution.