Chemical fractionation of heavy metals in soils around oil installations, Assam

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

“…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].…”

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

“…Similar results have been reported by many investigators (Ma and Rao, 1997;Kotoky et al, 2003;Zahyah et al, 2004;Horsfall and Spiff, 2005;Iwegbue et al, 2007). The percentage of cadmium in this fraction suggests …”

“…Low levels of nickel were associated with the Fe-Mn oxide and organic fractions (4.98% and 4.14% respectively). Low levels of nickel in these fractions have been reported by Kotoky et al (2003). Iwegbue et al (2007) reported a significant level of nickel in organic fraction and a relatively low level in the Fe-Mn oxide fraction.…”

Trace metals distribution in different geochemical phases of soils around automobile junk markets in southern Nigeria

“…The proportion ranged from 21.43 -33.33% with an average of 26.98%. This result corroborates the findings of Kotoky et al, (2003), Iwegbue (2011), Osakwe (2013, Liang et al, (2014). The predominance of chromium in this fraction implies low solubility of the metal and its unavailability to biota.…”

“…The amount of Nickel associated with this fraction indicates that a relatively substantial proportion of nickel in these soils is of geogenic origin and its mobilization is not possible. Moral et al, (2005) (Kotoky et al, 2003;Osakwe and Okolie, 2015).…”