Chemical partitioning of iron, cadmium, nickel and chromium in contaminated soils of south-eastern Nigeria

Abstract

Selected heavy metals Fe, Cd, Ni and Cr were studied in contaminated soil samples collected from south-eastern Nigeria. Geochemical differentiation into different chemical fractions, using Ma and Rao six-step sequential chemical extraction procedure, was carried out to assess the potential mobility and bioavailability of the heavy metals in the soil profiles.

Partitioning Of Some Trace Metals in Floodplain Soil in Onitsha, Anambra State, Nigeria.

“…Cadmium was found to be 6.06% of this fraction. This result was in line with some other similar studies [23,26]. The fraction could be considered relatively stable but could change within variations in redox condition [26].…”

“…The % occurrence of iron was 3.03. This corroborated the findings of Osakwe [23] where iron had an average value of 3.06%. Cadmium was found to be 6.06% of this fraction.…”

“…In this study, zinc had the highest occurrence (52.73%) while manganese did not occur (0%). Low level of nickel (3.03%) was in agreement with other findings [23,24,25]. It has been suggested that the levels of nickel in this fraction depends on how much manganese oxide is absorbed in soil because Ni 2+ can substitute for surface manganese in mixed valence manganese oxides [23].…”

“…The most significant occurrence of Nickel was in carbonate fraction (7.33%). This result compared favourably with similar study [23] where nickel had an average value of 10.47%. The % occurrence of zinc in this fraction fell within the values obtained in a similar study (7.90-10.02%) by Adaikpoh [21], while manganese in this fraction was detected to be 5.13% which is lower than the value obtained by the same author.…”

“…Organically complexed cadmium was not detected. Low level of cadmium in this fraction has been reported [23]. The high distribution of iron and zinc in bound to organic matter is expected due to the strong complexes these metals tend to form with humic material [15].…”