Sedimentary Assessment of Basic River in the Niger Delta: A Case Study of Orashi River in the Eastern Niger Delta of Nigeria

Abstract

Ecosystem in the Niger Delta has become a sanctuary for most endangered species, including mangrove and several forest reserve. The ketstone role of River Orashi in the Niger Delta is remarkable. The quality of River sediment very key in defining the bioavailability of aquatic system. The sedimentary assessment of River Orashi was carried out in six sampling stations (Mbiama, Agbo, Akiogbologbo, Okaki and Okparaki), in both Dry and wet seasons. Result showed that; pH ranged from 6.53-7.05, while Electrical Conductivity ranged from 124.31-590.01 µS/cm. While nitrite was 0.12-0.47 mg/kg, nitrate ranged from 0.72-3.76 mg/kg. The values of Sulphate and Phosphate were; 0.33-0.85 mg/kg and 0.24-0.43 mg/kg. Calcium ranged from 3.68-8.03 mg/kg, while magnesium was 1.99-6.86 mg/kg. Sodium and potassium were reported as 2.23-4.47 mg/kg and 1.41-3.62 mg/kg respectively. Other results reported includes; Nitrogen (2.52-4.63 mg/kg), Organic carbon (7.78-10.51 mg/kg), Carbon-Nitrogen (2.23-3.51 mg/kg), Total Hydrocarbon Content as in THC (4.96-9.62 mg/kg). Also on a general note, other parameters monitored were moderate, while electrical conductivity (EC) and all nutrients (Calcium, Magnesium, Sodium, Potassium, Nitrite, Nitrate, Sulphate and Phosphate), were higher in the Dry season. Our findings revealed mild anthropogenic activities within the Orashi River. We therefore call on all stake holders and inhabitants around the River Orashi to desist from anthropogenic activities that could infringe on biodiversity or public health.

Chemometric Assessment of Orashi River after Confluence with Oguta Lake

“…The length of the river is more than 7 km. The area has a tropical humid hot climate with two major seasons, rainy season (between March and October) and the dry season (between November and March) [7,8].…”

“…Waste dumpsites are the major sources of heavy metals pollution in the river through surface run-off. Earlier studies reveals that both the surface water and the sediments are under anthropogenic stress and mildly polluted [7,8]. However, no study has focused on the confluence point of the river with Oguta Lake.…”

Diversity and Levels of Bacteriological Contamination in Orashi River, Mbiama Community, River State, Nigeria

“…Mbiama which is situated in the Ahaoda West Local Government Area of Rivers State is one of the communities the River Orashi passes. River Orashi lies between latitudes 50º 45″ and 60º 35″ N and longitudes 40º 50″and 50º 15″ E [20,21]. The River Orashi is one of the major rivers in the Easter Niger Delta [20].…”

“…River Orashi lies between latitudes 50º 45″ and 60º 35″ N and longitudes 40º 50″and 50º 15″ E [20,21]. The River Orashi is one of the major rivers in the Easter Niger Delta [20]. The geology of the area is characterized by a vast flood plain built up sedimentary deposits [21], the area has two predominant seasons including wet (April to October) and dry (November to March of the following years).…”

“…Several studies have been carried out in the water quality in the Niger Delta especially in Bayelsa state [6,7,9,[14][15][16][17][18][19]. Furthermore, previous studies have been carried out in Orashi River with regard to the sediment [20] and water quality [21]. Therefore, these present study focus on the level of bacterial contamination in Orashi River, Rivers state, Nigeria.…”