Sediment oxygen demand of the Serin river

Stream sediment is a sink for organic materials. Though Serin River is a source of drinking water, agricultural activities in the watershed may impact the sediment of the river thus affecting its water quality. Therefore, the objective of this study was to investigate the organic matter and oxygen demand of the sediment at three selected stations (1: upstream station, 2: downstream of fish culture, and 3: downstream of pig/ chicken farm). Sediment was sampled from the selected stations and the oxygen demand measurement was conducted in the laboratory. Results of this study indicate that organic matter ranged from 6 to 11 O2/m2/d. Among the stations, oxygen demand of the sediment was the highest downstream of chicken and pig farming. Station 1 with sandy sediment had the lowest concentration of organic matter and oxygen demand of all stations. Sediment oxygen demand was negatively correlated with sand content. This study indicates that animal farming and fish aquaculture have impacted the organic matter content and oxygen demand of the sediment of river. There is evidence of positive effects of pig farm oxidation ponds wastewater treatment as sediment oxygen demand downstream of the discharge was not the highest among the stations. Agricultural effluents should be well-treated to protect the river sediment from being polluted