2.3 Sediment Sampling and Analysis
On site analysis of the pH of the sediment was conducted using a soil pH meter. Core samples of at least 1meter depth were collected using an auger. The inclusion of subsoil horizons is the ideal depth for a study on elemental leaching [2]. A total of 15 core samples were collected covering the middle of the stream and both sides of the riverbanks. The composite sample from each station was packed in polyethylene bags, chilled and transported within the day to the laboratory for analysis. Samples were homogenized, air dried and oven dried at 110̊C for three hours. The samples were divided into three for three types of analysis namely, grain size analysis, organic matter content analysis and metal content analysis [14,15,13] respectively. The samples were sieved using a sieve plate (0.002mm) as sediments at this particular size and lower are considered silt [14]. The dried samples were weighed (W1) and exposed to 600̊C muffle furnace to obtain pure inorganic matter. This was weighed (W2) and the computation was made to determine the organic matter content (OM) content