Some trace metals content of atmospheric dusts deposition in Katima Mulilo metropolis, Namibia

Type Journal Article - Journal of Environmental Science, Toxicology and Food Technology
Title Some trace metals content of atmospheric dusts deposition in Katima Mulilo metropolis, Namibia
Author(s)
Volume 8
Issue 2
Publication (Day/Month/Year) 2014
Page numbers 5-13
Abstract
Trace metals content of atmospheric dusts continue to attract global attention as more anthropogenic
activities including urban road construction impacted on the natural metals load of airborne particulates. This
study employed analytical procedures to investigate the concentrations of arsenic, cadmium, cobalt, chromium,
copper, nickel, lead, vanadium, tin and manganese in atmospheric dusts deposition in Katima Mulilo
metropolis, Namibia. Replicate samples were collected on five days interval under dry winter conditions from
mid- August to mid-October, 2013. Samples were collected from within 40 m radius at selected locations along
Katima Mulilo urban road construction and from a quite residential area; 2 km away from the road work.
Processed samples were digested by EPA method 3050B followed by Inductively Coupled Plasma-Optical
Emission Spectrophometer (ICP: Perkin Elmer Optima 7000 DV) analysis. The results obtained showed that
manganese recorded the highest concentration in the dusts deposition collected within the urban road
construction (155.67±2.52 mg/kg) and residential area (64.00±2.64 mg/kg) respectively. Tin recorded the
lowest concentration with mean levels of 0.60±0.10 mg/kg along the road construction and 0.24±0.07 mg/kg in
the residential area. T-test analysis of the variations in concentrations of the trace metals were statistically
significant (p < 0.05). However, the levels of the trace metals recorded in this study were lower than their
permissible concentrations recommended by Canadian soil quality guidelines for the protection of environment
and human health. There is a very strong positive inter-elemental correlations and the metals enrichment
factors showed moderate enrichment. These suggested common and input from anthropogenically induced
sources respectively. Single element pollution indexes of the metals showed low contaminations but the levels of
arsenic, cadmium, nickel and vanadium in the atmospheric dusts deposition could become source of health
concern following environmental accumulations and non-biodegradation of the trace metals. Thus, it is
recommended that periodic evaluation of the trace metals content of the atmospheric dusts deposition should be
sustained to monitor future accumulation.

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