ENVIRONMENTAL QUALITY ASSESSMENT ALONG CORRIDORS OF HIGH TRAFFIC ROADS IN KANO METROPOLIS, NIGERIA
ENVIRONMENTAL QUALITY ASSESSMENT ALONG CORRIDORS OF HIGH TRAFFIC ROADS IN KANO METROPOLIS, NIGERIA
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Date
2012-10
Authors
OKUNOLA, OLUWOLE JOSHUA
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Abstract
This study was aimed at assessing the variation of concentrations of total and
species of Cd, Cr, Ni, Pb, Cu and Zn in atmospheric dust particulate and roadside surface
soil samples, and air pollutants (CO, H2S, NO2, SO2, FL and NH3) along busy roads in
Kano Metropolis due to increase in automobile over the years. The study was carried out
across cool and dry, hot and dry, warm and wet and warm and dry seasons. Other
parameters which were investigated included, particle size distribution, pH, electrical
conductivity (EC), organic matter (OM) and the cation exchange capacity (CEC) of the soil
samples, and sound level and temperature. Atmospheric dust particulate and soil samples,
traffic data and air pollutants (including hourly average) were collected from ten selected
busy roads and a control site (from a garden) in the metropolis. The soil samples were
sieved to produce samples of different particle sizes (1400μm, 355μm and 150μm). For
total Cd, Cr, Ni, Pb, Cu and Zn concentrations, the samples were digested with aqua regia,
and a six-stage sequential extraction protocol was used for their chemical fractionation.
Statistical evaluation of the results obtained showed significant differences (p < 0.05)
across the sites and seasons. Generally, total metal extraction revealed high concentration
that depict high ecological risk, however, the sequential extraction showed that availability
of these metals are low to the immediate environment. This implies that risk assessment
using total metal concentration is not enough to conclude that an environment is polluted.
The results of gaseous pollutants showed that concentrations of CO, H2S, NO2 and SO2
measured with few exceptions at some sites were above the air quality index AQI stipulated
by USEPA especially during the afternoon periods. This implies that traffic emission within
Kano metropolis is not within the safe limits.
Description
A DISSERTATION SUBMITTED TO THE
SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR
THE AWARD OF DOCTOR OF PHILOSOPHY IN
ANALYTICAL CHEMISTRY
DEPARTMENT OF CHEMISTRY, FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
OCTOBER, 2012
Keywords
ENVIRONMENTAL, QUALITY, ASSESSMENT, CORRIDORS, HIGH TRAFFIC, ROADS, KANO METROPOLIS, NIGERIA