Assessment of Seasonal and Spatial Variation of the Organic Carbon and Nutrients in the Ghaghara River Sediment

To assess the organic carbon and nutrients content and its seasonal and spatial variation, sediment samples were collected three times from 18 different locations starting from Keuna, Nepal to Doriganj, Bihar from Ghaghara River during the year 2018-19. The value of pH varied from 7.6 to 8.8 during the study period and indicated the alkaline nature of the sediment. The electrical conductivity (EC) value varied from 0.09 to 0.47 (m S cm-1) in the study area, which shows the contribution of the anthropogenic input mainly from domestic and industrial sources to the sediment of the Ghaghara River. The sediment organic carbon (SOC) was in the range of 0.14 to 1.26 %, with relatively higher concentrations during the post-monsoon and monsoon season. The concentration (Mean ± SD) of nitrate, ammonium, phosphate, sulphate and silica in the sediment samples of Ghaghara River were 7.05 ± 1.19, 5.5 ±1.7, 1372 ± 509, 562 ± 157, and 159306 ± 36192 (mg kg-1), respectively, during post-monsoon season, 2.05 ± 0.59, 18.0 ± 5.2, 1814 ± 318, 602 ± 139, and 180152 ± 52098 (mg kg-1) in pre-monsoon season, and were 7.3 ± 3.3, 7.8 ± 1.4, 1835 ± 696, 438 ± 85, and 163625 ± 68143 (mg kg-1) in monsoon season, respectively. The bulk density (BD), pH, EC, nitrate, ammonium, sulphate, and phosphate content showed significant seasonal variation and in the case of spatial variation, while only EC and sediment organic carbon showed significant variation in the Ghaghara river sediment.