Research
Geo-accumulation and Ecological Risk Assessment of Heavy Metals From Roadside Dust Around Forces Avenue, Old GRA, Port Harcourt, Nigeria
Samples from roadside dust collected from different stations in Forces Avenue, Old GRA, Port Harcourt, Rivers State, Nigeria were digested (mineralized) and subsequently analyzed for heavy metals concentration. The result of the investigation showed that Iron (Fe) was the most abundant metal detected in the roadside. The highest value of Fe was obtained in station 2, which was 81.40±8.12 mg/Kg. The order of concentration of the metals was iron (Fe) >zinc (Zn) > nickel (Ni) > copper (Cu) > lead (Pb) >cadmium (Cd) > chromium (Cr). The mean concentrations of the heavy metals from the various stations was: Fe (71.08±5.38), Zn (47.34±6.05), Ni (25.27±0.99), Cu (18.08±0.93), Pb (0.54±0.05), Cd (0.36±0.03) and Cr (0.18±0.05) mg/Kg. Contamination factor analysis showed that the Forces Avenue area is within contamination category, but not yet polluted with heavy metals. Geo-accumulation index and ecological risk assessment interpretations showed that the concentration of heavy metals in the environment arose from natural factors and pose no ecological risk to the environment. However, adequate care and control should be put in place to put the environment under check to avert possible rise in the concentrations of the metals especially Zn, Ni and Cu.
Seasonal Assessment of Heavy Metals in Water at Effluents Discharge Points into the New Calabar River, Port Harcourt, Southern Nigeria
Water samples were collected at three different effluents discharge points into the New Calabar River. The samples were digested using standard methods. The digests were subsequently examined for heavy metals concentrations using atomic absorption spectrophotometer (AAS). Heavy metals results in the samples showed Ni as the most concentrated metal with a mean value of 2.52±0.055, 1.42±0.01 and 1.275±0.045 mg/L at Iwofe, Jetty, Minipity and Police Post stations respectively, this was followed by the concentration values of Cr, which were 1.72±0.06, 2.17±0.02 and 1.355±0.015 mg/L at the Iwofe Jetty, Minipiti and Police Post sample stations respectively. The least concentrated metal observed in this study was Cd with a mean range of 0.03 - 0.28 mg/L in the stations. This was followed by the values of Cu from the station which ranged between 0.035 - 1.22 mg/L. The general order of the concentration of metals was Ni > Cr > Fe > Zn > Pb> Cu > Cd. All the metals examined in the water samples except Zn were higher than the WHO maximum standard for drinking water. Contamination factor analysis showed that the samples were either severely or excessively polluted by most of the metals. However, Zn and Cu were within the range of contamination in the sampled stations. Pollution load index indicated that the stations ranged from severe pollution to excessive pollution. Contamination degree assessment indicated very high degree of contamination and the modified degree of contamination showed that all the stations were within ultra high degree of contamination. Generally, the result indicated a high degree of water pollution by heavy metals at the discharge point. Therefore caution should be taken to control the sources of these pollutants, which have put this aquatic environment under serious threat.
