Abstract:
The use of mineral magnetic techniques as
pollution proxy for road deposited sediment was explored
using various statistical approaches. Standard techniques
were adopted for measurement of mineral magnetic and
geochemical parameters. The analyses of magnetic
parameters revealed that the samples were dominated by
ferrimagnetic minerals and multidomain grains. This
implied that the magnetic fractions in the samples might
be of anthropogenic origin. Results also indicate that the
samples were dominated by low coercive, magnetically
soft minerals. Thermomagnetic curves confirmed magnetite
as the remanence bearing magnetic mineral having
a Curie point temperature of *580 C. The strong association
observed between magnetic susceptibility, susceptibility
of anhysteric remanent magnetization and
saturation isothermal remanent magnetization and aluminum,
titanium, manganese, iron, chromium and lead
demonstrated that these metals occurred as ferrimagnetic
particles of technogenic origin resulting from vehicular
sources. Assessment of pollution status of the road
deposited sediment identified silicon and lead as the priority
pollutants of concern. Generally, pollution load
index was \1 (mean, 0.66 ± 0.14), indicating that the samples were not polluted in the overall, but the metals
were in the buildup stage requiring constant monitoring.
The sources of pollutants from principal component and
cluster analyses identified the sources of pollution to be
mainly from vehicular emissions such as brake linings,
exhaust materials, tire wear, corroded metal parts, abrasion
of lubricating oil and road construction materials.
This study found that mineral magnetic techniques offer
great potential as pollution proxy for soil pollution
studies.
