Dissolved N2O, CH4, and CO2 in pipe drainage, seepage, and stream water in a livestock farm in Hokkaido, Japan

Abstract

We confirmed that multiple phase equilibration could be applied to the simultaneous determination of the concentrations of dissolved N2O, CH4, and CO2. To investigate the presence of indirect greenhouse gas emissions, we measured the concentrations of dissolved N2O, CH4, and CO2 in pipe drainage, seepage, and stream water in a livestock farm located in Hokkaido, Japan. Large spatial and seasonal variations in the gas concentrations in the pipe drainage and seepage were observed: the concentrations of the dissolved gases ranged from 0.06 to 95.2 μg N2O-N L-1, from 0.03 to 3,400 μg CH4-C L-1, and from 3.34 to 53.9 mg CO2-C L-1. Almost all the concentrations were supersaturated, indicating the possibility of indirect N2O, CH4, and CO2 emissions from the farm. The N2O and CO2 concentrations in the stream water were near equilibrium with ambient air and were almost constant from the upstream to the downstream. However, the concentration of dissolved CH4 was remarkably higher in the lower part of the stream, suggesting that there may be a relatively strong indirect CH4 emission from the drainage in the lower part of the farm.