Physico-Chemistry of Elechi Creek in the Upper Bonny Estuary, Rivers State, Nigeria

Abstract

The physico-chemistry of tidal Elechi Creek in the upper Bonny Estuary was investigated to assess the toxicity of the water body as this could have adverse effects on the native organisms that form part of the ecosystem and to evaluate the extent and magnitude of petroleum hydrocarbon and heavy metal concentration in the water body. Standard field procedures were adopted in sample collection while laboratory analysis was carried out also following standard methods. Parameters measured include pH, temperature, dissolved oxygen (DO), biological oxygen demand (BOD), electrical conductivity, salinity and total dissolved solids (TDS). Heavy metals namely Copper (Cu), Lead (Pb), Zinc (Zn), nitrate (NO 3 ), sulphate (SO 4 ), Ammonia (NH 4 ), and Total Hydrocarbon Concentration (THC) in the surface water body were also determined on samples collected from five (5) sampling stations spread along the creek in both dry and wet seasons. The results showed that the surface water body is oligohaline with low acidity, pH values ranging from 6.2 to 7.6. Temperature varies from 27˚C to 30˚C. Dissolved Oxygen (DO) concentration ranges from 2.9 to 7.5 mg/l which is adequate for aquatic organism with Biological Oxygen Demand (BOD) values varying from 0.45 to 7.0 mg/l. The values of total dissolved solids (TDS) vary from 11,700 mg/l to 26,250 mg/l with the highest mean value obtained at the study station located downstream. The mean nutrient concentration showed that the study area is not eutropic. Anthropogenic activities were very high at the sites throughout the period of the study and may have resulted in the stress conditions of the area. Pollution trend along the study stations showed that no one station is unpolluted. The study recommends the introduction of enforceable and stringent waste management plans to highlight and discourage direct discharge of untreated waste and storm water runoff into an aquatic environment.

Water Quality Assessment of Elechi Creek Receiving Effluent Discharges from Industrial Activities in Port Harcourt, Nigeria

“…This could be due to the constituents of the wastewater arising from storm water runoff and other anthropogenic activities in the settlements around the creek. The pH values are in consonance with previous research reports by other workers [18,19,20]. Although the values obtained in this study were within WHO permissible limits of 6.5 -8.5.…”

“…In this study, the variations of DO of the water samples across the stations in both surface water and wastewater ranged from 2.90 to 3.15mg l -1 in stations 1 and 4 respectively for surface water and while 2.55mg l -1 was recorded in station 5 and 3.30mg l -1 in station 3. These values are in agreement with studies by other researchers [18,20]. According to Ekubo and Abowei [23], fishes can die if they are exposed to less than 0.3mg l -1 of DO for a long period of time, but can survive in water bodies of DO of 8.0mg l -1 and above.…”

“…According to Ekundayo [24], contamination of water with faeces increases the BOD 5 hence it contains organic matter which makes oxygen deplete faster and unavailable to desirable organisms. The values of BOD 5 obtained in the study were considerably high compared to the previously reported values by [20,25], this clearly means that the pollution of the creek by organic matter and industrial discharges have increased and it must be attended to before it causes serious damage to the water environment. The BOD of a river must generally not exceed 4.0mg l -1 as this would reduce DO from saturating to 5.0 -6.0mg l -1 which is still capable of supporting aquatic life [26,4].…”

“…is an indication of serious pollution [18,20]. According to Ekundayo [24], contamination of water with faeces increases the BOD 5 hence it contains organic matter which makes oxygen deplete faster and unavailable to desirable organisms.…”

Morphometric Characters and Meristic Counts of Black Chin Tilapia (Sarotherodon melanotheron) From Buguma, Ogbakiri and Elechi Creeks, Rivers State, Nigeria

“…Similar values have been reported by Chindah [22] in the main channel of the Bonny estuary, in the rainy season, when fresh water discharge was heaviest. Similarly, Ngah et al [23] also reported that low salinity in bonny tidal basin is influenced by fresh water discharge.…”