Environment
Gregory Udie Sikakwe; Samuel Adebayo Ojo; Andrew Aondover Tyopine
Abstract
Potentially harmful elements enter into the environment through mining and agricultural activities, causing water and stream sediment pollution. Ecological risk analysis helps to determine sediment pollution, to recommend remediation measures for human health safety and the survival of aquatic ...
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Potentially harmful elements enter into the environment through mining and agricultural activities, causing water and stream sediment pollution. Ecological risk analysis helps to determine sediment pollution, to recommend remediation measures for human health safety and the survival of aquatic species. The sediments were analysed for acidity and redox potential using a pH-meter and spectrophotometer, respectively. Nickel, cadmium, arsenic, chromium, lead, zinc, and iron were measured using atomic absorption spectrophotometer. The mean value of Cd exceeded the threshold effect limit guideline indicating its adverse effect to water dwelling organisms. Anthropogenic metal input identified cadmium, lead, arsenic, zinc and chromium contamination in locations 3, 6, and 7. Modified risk assessment code, toxic response index and comprehensive ecological risk values exhibited considerable to high ecological risks in locations 3, 6, and 7. The highest comprehensive ecological risk value recorded 653.2 in location 3, showing high ecological risk to water dwelling organisms. Durbin Watson ecological risk value (2.34) is between a critical value of 1.5 < d < 2.5 showing auto correlation of the data. Potentially harmful elements obtained Durbin Watson value of 2.77, which exceeded the range showing lack of auto correlation. Strong correlation of arsenic, lead and zinc showed their affinity and common source of enrichment. Principal component analysis indicated that the sources of the elements were mostly geological weathering, sewage disposal, industrial wastes and agricultural fertilizers. The study integrated recent ecological risk indices with multivariate and regression statistics. This is helpful in interpreting related environmental problems by scientists in other parts of the world.
Environment
G.U Sikakwe
Abstract
In this work, the concentrations of the potentially toxic elements in stream sediments in SE Nigeria were assessed for pollution monitoring in mining, quarrying, and farming areas. The levels of iron, molybdenum, vanadium, copper, lead, zinc, nickel, cobalt, manganese, chromium, barium, and beryllium ...
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In this work, the concentrations of the potentially toxic elements in stream sediments in SE Nigeria were assessed for pollution monitoring in mining, quarrying, and farming areas. The levels of iron, molybdenum, vanadium, copper, lead, zinc, nickel, cobalt, manganese, chromium, barium, and beryllium were determined. The concentrations of the elements were in the order of Fe > Ba > Mn > Cr > Zn > Pb > Cu > Co > Ni > As > Mo. There were significant positive correlations at P < 0.01 between Mo and Cu (r = 0.734), Mo and Pb (r = 0.811), and Cu and Pb (r = 0.836). The others were between Cu and V (r = 0.748), Pb and V (r = 0.793), Fe and V (r = 0.905), Fe and Be (r = 0.703), V and Be (r = 0.830), Cu and Pb (r = 0.778), and Fe and V (r = 0.905). The geoaccumulation index values were classified as polluted (0-1) to moderately polluted (1-2). The enrichment factors fell into moderate, significant, and very high enrichment. Pb, Co, and Ba attained significant enrichment factors. The potential ecological risk showed a strong risk level "C" in only three locations. Arsenic was a strong factor carrying risk. The potential ecological risk (EiR) trend was EiR (AS) > EiR (Pb)> EiR (Cu) > EiR (Co) > EiR (Cr) > EiR (V) > EiR (Ni) > EiR (Zn). Ba, Pb, and As should be monitored further to determine their source and recommend possible remedial measures. The result of this work could be used to improve water management efficiency and serve as a benchmark of vulnerability assessment of the studied area. This could also be useful for future impact assessment and adequate planning of mining and farming areas. In addition, the result obtained could assist the scientists to make appropriate environmental management strategies to reduce the influence of metal contamination triggered from the mining sites and farming areas both in Nigeria and globally.
