Sources and Distribution of Polycyclic Aromatic Hydrocarbons in Wet Deposition in Urban and Suburban Areas of Giza, Egypt

Mamdouh I. Khoder

Department of Air Pollution Research, National Research Centre, Dokki, Giza, Egypt

Corresponding author: Mamdouh I. Khoder
    Department of Air Pollution Research, National Research Centre
    Dokki, Giza, Egypt
    Telephone: +202 3371433/1402
    Fax number: +202 3370931
    E-mail: khoder_55@yahoo.com

CEJOEM 2006, Vol.12. No.4.: 279–296

Key words:
Urban/suburban/rural areas, wet deposition, suspended particulate matter, polycyclic aromatic hydrocarbons, carcinogenic compounds

Abbreviations:
ACE
ACY
ANT
BaA
BaP
BbF
BGP
CRY
DBA		 = acenaphthene
= acenaphthylene
= anthracene
= benzo(a)anthracene
= benzo(a)pyrene
= benzo(b)fluoranthene
= benzo(ghi)perylene
= chrysene
= dibenzo(a,h)anthracene		 FLU
FLT
IND
LMW
NA
PAHs
PHE
PYR
.		 = fluorine
= fluoranthene
= indeno(1, 2, 3,–cd)pyrene
= low molecular weights
= naphthalene
= polycyclic aromatic hydrocarbons
= phenanthrene
= pyrene
.

Abstract:
Wet deposition (rain) samples were collected at three locations, two in urban and suburban areas of Giza (Dokki and Kafr Tohormos) and background ones in a rural area of Menofiya province (Kafr El-Akram) during the period of November, 2004 – April, 2005. In the suburban area, the particle-bound PAH concentrations in suspended particulate matter were also determined before and after rainfall. The highest concentrations of PAH compounds in wet deposition were found in the urban area, whereas the lowest concentrations were detected in the rural area and the differences in mean concentrations were statistically significant (p<0.001). The concentrations of the total PAH compounds were 25.897, 13.647, and 0.023 µg/L in the particulate phase, 11.288, 6.365, and 0.0871 µg/L in the dissolved phase, and 37.185, 20.012, and 0.1101 µg/L in the particulate+dissolved phases in rain water at the urban, suburban, and rural areas, respectively. Benzo(b)fluoranthene, benzo(ghi)perylene, and benzo(a)anthracene were the dominant PAH compounds in wet deposition at both urban and suburban sites, indicating that a significant fraction of heavy PAH compounds were emitted from traffic due to the incomplete combustion of fuel. On the other hand, naphthalene, phenanthrene, anthracene, and fluorine were the predominant PAH compounds in wet deposition in the rural area, indicating that the PAHs of lower molecular weight predominated. The total carcinogenic PAH compounds represented 59.68, 59.19, and 21.62% of the total PAH concentrations in wet deposition in the urban, suburban, and rural areas, respectively. In suspended particulate matter, the concentrations of the total PAH compounds in the suburban area were 1588.7 and 609.65 µg/g before and after rainfall, respectively. Motor vehicles were the major source of PAHs in the atmosphere of the areas studied and, consequently, in the wet deposition, and they mainly originated from pyrolytic processes.

Received: 17 October 2006
Accepted: 30 January 2007
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