Bio Monitoring Of Atmospheric Heavy Elements In Urban And Industrial Areas Over Alexandria


Author: Chem / Mohammed Anas Emara

Air pollution is a major problem facing all nations of the world. Increasing industrialization and human activities intensify the emission of various pollutants into the environment and introduce various harmful substances into the atmosphere. Recently, air pollution problem has drawn a lot of attention for studying its impact on different organisms. Alexandria is a big industrial city that hosts 40% – 50% of the industrial power in Egypt. There is a large variety of industrial activities in Alexandria like refineries, petrochemicals, chemicals, cement factories, fertilizers and iron industries. Emissions from such industries and heavy traffic in the city as well as the activities of construction and demolition of the buildings aggravate air pollution problem. The emission of trace elements like Pb, Cd, Cr, Fe, Ni, Mn, Mo, Cu, Zn and V is considered the major source of air pollution. The present study was carried out using leaves of Ficus retusa L. trees as a bio indicator of atmospheric trace elements in urban and industrial areas over Alexandria. Estimation of Dust and leaf Area: The atmospheric dust deposited on the leaves of Ficus retusa L. was estimated by (µg/cm2) in each study location, where the leaves were carefully washed with distilled water which are put in porcelain crucibles then put in an oven with a temperature 1050C till they reach a constant weight so as to let the water evaporates. Also, the total leaf area (cm2) was estimated by using digital planimeter (Bolab model 40). In the investigation, the variation in dust accumulation on the leaves of Ficus retusa L. in both seasons (spring and autumn); as affected by traffic density along Abu-Qir street as well as carbon black factory and some petrochemical companies at El-Amryya district besides cement dust at El-Max region, were quite clear. Trace Elements Determination: The concentrations of trace elements were carried out by the digestion of samples using a mixture of acids (HF, HNO3 and HCLO4) and determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Ficus retusa leaf samples collected from industrial sites in the present study had significantly higher concentrations of Cu, Mo, Zn, Mn and Co during autumn than the background site. Similarly, the elements; Cu, Pb and Zn attained their maximum concentrations under traffic stress in the same season. Determination of the Photosynthetic Pigments: The photosynthetic pigments; chlorophyll a, b and carotenoids were extracted and determined using the spectro-photometric method. It was noticed that Ch”a”, Chl “b”, carotenoids and total pigment in the present study decreased significantly during autumn with the increase in dust accumulation. The values obtained in the control site were greater (low dust accumulation) than those of traffic and industrial locations. The results of the present study indicated that Ficus retusa trees are very sensitive to air pollutants, and may consider as a bio indicator (biological indicator) for atmospheric pollution and can be used to determine the locations of trace element sources. Recommendations: It is recommended that: Local authorities in Alexandria Governorate need to follow a monitoring policy and carry out a general regular audit for the industrial complex (petrochemical plant) and El-Max area in general, in order to comply with the environmental requirements for the sake of a better environment and lifestyle equity. Using bio monitoring techniques to monitor these elements and air pollutants and study their effect on living organisms. The effect of increasing heavy elements on public health should also be investigated and used as a health indicator.