Temporal variations of heavy metals in sediment, soil and dust particulates across the rock quarrying districts of the Oban Massif, Southeastern Nigeria

Abstract

Concentrations and distribution trends of selected heavy metals (Fe, Mn, Cu, Pb, Zn, Cd, Cr, Ni and As) in sediment samples, soil and dust particulates across the rock quarrying districts of the Precambrian basement Oban Massif, southeastern Nigeria were determined. The quarrying district was zoned into A comprises of quarries with operational histories of more than twenty years and B which were of younger age. Calculations from data sets gave information on metal enrichment factor, contamination factor, geo-accumulation index and pollution load index. Results revealed the trend: Fe > Mn > Zn > Ni > Cu > Pb > Cd > Cr > As in zone A and Fe > Mn > Zn > Ni > Cu > Cd > Cr > Pb > As for zone B. Contamination factors of heavy metals in samples across the two zones were generally low. Enrichment factor indicates mostly deficient to minimal enrichment. However a few localized samples indicate moderate, significant and extremely high enrichments in Pb, Zn and Ni. Pollution load index (PLI) of the heavy metals in sediment samples, soil and dust particulates from both zones indicates no pollution. Geo-accumulation index (Igeo) of metals across zones is largely of the unpolluted category. The observed values of heavy metal contamination in sediment, soil and dust particulates as well as their enrichment, PLI and Igeo were generally higher in the older than the younger quarrying zones of western Oban Massif.