Methane concentration decreased in a linear manner with EuO
supplementation at 25, 50, 100 and 150 µl by 26.0, 46.8, 77.3 and 85.3% relative to control,
respectively, while the reduction in methane volume was 29.9, 59.8, 82.4 and 90.3% with
increasing level of EuO.