Some Physical and Chemical Characteristics in Okpoka Creek, Niger Delta, Nigeria

Abstract

Some physical and chemical characteristics in okpoka creek was studied for one year. There was a long wet season stretching from April to October in and a dry season extending from November to March. The total monthly rainfall ranged from 1.8mm to 399.6mm. The highest total rainfall (399.6mm) was recorded in July while the lowest rainfall (1.8mm) was observed in January. The atmospheric temperature fluctuated from 28.5°C in July to 33°C in March. The monthly water temperature values ranged between 27°C and 31°C across the Stations. The mean temperatures were similar along the Stat ions (P£0.05) ranging from 28.98±0.23°C (Station 4) to 29.77±0.15°C (Station 5). A steady trend of temperature was observed in Stations 1, 2 and 4 as well as in stations 3 and 6. Generally, temperature values were stable across stations. Maximum temperature of 31°C was recorded in January, February, March, July, and October. While the lowest temperature of 27°C was observed in July, August and September. There was slight seasonal variation of temperature between dry (29.49±0.11°C) and wet season (29.09±0.125°C). A steady trend of temperature variation was observed. The mean pH value ranged between 6.68±0.07 (Station 1) and 7.03±0.05 (Station 6). The Spatial and temporal variations of pH were minimal. Seasonal variation in pH was observed between dry season (6.97±0.044) and wet season (6.81±0.367). Salinity val ues ranged between 0.60‰ and 20.90‰. The highest sal inity value ( 20 . 90 ‰) was recorded in June at station 6 and the lowest salinity value (0.60‰) was observed in October at station 1. The means varied from 4.75±0.79 (Station 1) to 12.65±1.36‰ (Station 6). There was spatial variation with a general trend that showed increased salinity values from station 1 to station 6. Some Seasonal variation was also observed with higher salinity during the dry season (11.67±0.517‰) than the wet season (6.98±0.701‰). Dissolved oxygen values values range from 0.4mg/L and 8.34 mg/L. The highest dissolved oxygen concentration (9.6mg/L) was observed in station 3 while the lowest value (0.4mg/L) was recorded in station 6. The mean dissolved oxygen concentrations ranged between 3.72±041mg/L and 5.10±0.29mg/L across the stations. There was no seasonal and annual variation observed in the concentrations of dissolved oxygen. Biochemical oxygen demand varied from 0.0mg/L to 6.4mg/L. The lowest biochemical oxygen demand value (0.0mg/L) was recorded in December and the highest value (6.4mg/L) was observed in station 1 (March) as well as station 4. The mean biochemical oxygen demand oxygen ranged between 1.97±0.28mg/L and 2.69±0.26mg/L across the stations. No sea sonal and temporal variations were observed in the biochemical oxygen demand. Monthly conductivity values observed ranged from 920mscm -1