Elemental composition of total dry particulate matter deposited in the selected industrial areas within Lagos state

Abstract

The total particulate matter (PM) deposited within 17 selected industrial areas in Lagos state during the dry season (December 2015 to January 2016) was studied. Deposition gauges measuring 0.2 meters (m) in diameter by 0.15 m in depth were placed at the sampling locations for a period of one month to collect the total deposited PM. The PM was then characterized using energy-dispersive X-ray florescence (EDXRF). The sources of the heavy metals were evaluated using enrichment factor (EF) analysis. Factor analysis (FA) was then used to determine the correlations between the identified heavy metals. Twenty-three elements-sodium (Na), silicon (Si), phosphorous (P), sulfur (S), chlorine (Cl), potassium (K), calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), germanium (Ge), arsenic (As), strontium (Sr), zirconium (Zr), lead (Pb), tungsten (W), polonium (Po), and actinium (Ac)-were characterized in the PM collected at the sampling sites. The iron elemental ratio ranged from 0.0003 to 3.8848. The EF ranged from 0.0015 to 1697.47, including at the control location. The FA, using principal component analysis techniques, revealed seven factor loadings with 90.03% cumulative, which suggests that the sources are anthropogenic, such as from industrial activities, vehicular emissions, and the combustion of fuel.

Atmospheric dristribution of traffic heavy metals at temu-interchange, Epe Lagos, Nigeria

“…This trend shows that the Lagos State University Epe Campus was more polluted with Iron (Fe). These average concentration values are higher than the value stipulated by the NAAQS [8,1].…”

“…Calculation of EF values help to determine whether a certain element has additional or anthropogenic sources other than its major crustal sources. Sources of metals in PM include both natural and anthropogenic processes [13,14,1]. Elements such as Al, Si, Ti, and Fe are commonly used as a point of reference for the calculation of factors, because they are very abundant in crustal material and are not significantly affected by pollution.…”

“…Heavy metals are the stable metals or metalloids whose density is greater than 4.5 g/cm3, namely Pb, Cu, Ni, Cd, Zn, Hg and Cr, etc. [1]. Evidently, some of these metals are essential for life at very low concentration levels but at high levels of concentration they may lead to harmful effects in humans, plants and animals [2].…”

“…Environmental challenges posed by the proliferation of human activities such as industrial effluent discharge, vehicular emissions, bush burning, wastes incineration and mining operations have become evident in the industrial and high traffic density areas of Epe, Lagos metropolis but there is dearth of baseline data on the levels of heavy metal pollutants in dust over the areas [1]. It was also observed that very little interest has been developed on metal contaminations of street dust despite its direct contact with greater part of every population [5,6].…”