Phytoremediation of The Air Pollution Using some Plants in Three Different Locations of Alexandria City

INTRODUCTION

Alexandria is the second capital of Egypt, it was the old capital, located on the Mediterranean coast. Alexandria city, one of the most culturally diverse and civilized cities, where many different historical periods throughout the ages have seen, where there are many ancient and modern monuments, became an open museum featuring Greek, Roman, Coptic and Islamic. The population of Alexandria city is about 4,123,869 people according to 2006 census (World Population Prospects) serving commercial, industrial and agricultural activities. Therefore, the issue of pollution is one of the important issues that threatened the throne of the tourist city, especially air pollution standpoint (Ghattas,1992). In Alexandria, some industrial areas started to contribute to the problem of air pollution due to the rapid growth of industrialization, besides the lack of planning for site allocation of industries.  Therefore, there were a considerable numbers of studies on industrial air pollution and its effects on the environment in Alexandria.  For instance, for the cement industry, many researchers tackled the problem of pollution monitoring, control, health effects and other factors caused by this industry (Abd El-Kader et al.,1979). Amer (1999) studied air pollution and planning of housing location in Alexandria.

Lead is widely distributed naturally, but the greatest risks normally arise from emissions to the environment associated with human use of the metal and its derivatives. Fumes and dust come from smelting of lead, manufacture of insecticides, paint, powdery glazes and storage batteries, and from gasoline containing lead additives. Sewage sludge may contain very high levels of lead and its use as a fertilizer may contaminate soils. High levels may occur in urban air as a result of the high traffic density and associated emission of lead from gasoline additives (Harrison and Laxen, 1981). Madany and Salim (1992), found that the concentration of lead in street and house dust were 697.2, and 360 µg/m³; respectively. It was suggested that the motor vehicles are the major source of these metals in dust samples.Jaffe et al.(1992) measured lead concentration in urban and rural area.  Urban concentrations were higher than rural concentration, Ghattas (1992).He found that the lead concentration in air of Alexandria, Cairo was averaged  0.259 µg/m³.

Cadmium is a normal constituent of soil and water at low concentrations. It is usually mined and extracted from zinc ores, especially zinc sulphide. Industrially, cadmium is used as an antifriction agent, and in alloys. In the environment, cadmium is dangerous because many plants and some animals absorb it efficiently and accumulate it within their tissues.Shalaby (1997) found that cadmium concentraion in air samples in urban area and rural area was 0.028, and 0.002µg/m³; respectively. Ghattas (1992) measured cadmium concentration in ambient environment at Alexandria, near Horreya avenue and found that Cd concentration was 0.0053 µg/m³.

Major uses of zinc are in the production of noncorrosive alloys, brass and in galvanizing steel and iron products. Zinc undergoes oxidation as surface coating, thus protecting the underlying metal from degradation. Zinc oxides are used in rubber and as a white pigment. Zinc is utilized therapeutically in human medicine in the treatment of zinc deficiency. The carbonates, which are organic zinc compounds, are used as pesticides (Friberg et al., 2002).Also they found that about 21-38 x 10³ metric tons of zinc per year is fallout. Shalaby (1997) found that zinc concentration in air samples in urban and rural area was of 0.5, 0.44, and 0.11µg/m³; respectively.

This study aims to see experimentally the effect of using two kinds of plants; Nerium oleander and Pittsporum tobira on reducing the air pollution level in three locations in Alexanderia city; El-Ebrahimeya, El-Dekhela and Antoniadis garden. Three highly dangerous heavy metals were detected through the study; Lead, Cadmium and Zinc.

MATERIAL AND METHODS

The present study was carried-out at the Horticulture Research Institute, Agriculture Research Center (A.R.C.) Alexandria, Egypt during the spring season (March-April) and the autumn season (October-November), 2015. The aim was to investigate the effect of phytoremediation of air pollution using one year old unpinched plants of (Nerium oleander and Pittsporum tobira) of about 50 cm height. 24 plants of each shrub were planted in three locations in Alexandria city.We applied these work in three different sites in Alexandria city namely:

1-  El-Ebrahimeya square which considered as a densely populated region and logged of a lot vechicles.

2-  El- Dekhela region which is considered as an industrial region.

3-  Antoniadis garden (Smouha) which is considered as a control region(less polluted).

1. Sampling:

1.1. Sampling of Total Suspended Particulate (TSP), Particulate Matter Less Than 10 micrometer (PM₁₀ ) , Lead, Cadmium and Zinc:

Samples were collected inside the working environment during the melting process and carried out using portable dust sampler type L-2SF.MK3 from Rotheroe and Michell. The sampler has a regulated air flow rate of 50 - 110 liter per minute. The inlet manifold of volume sampler was two meters height from the ground surface. Samples were collected on Whatman GF/A fiberglass filter of 7 cm diameter with a 99% - >99.99% collection efficiency for 0.035 - 1 μm particles (Kathren, 1984).

1.2. Digestion Method:

For measuring lead, cadmium and zinc concentrations, the filter paper was placed in desiccators for 48 hrs prior and after the sampling. The analytical balance (Meter) of 0.1 mg sensitivity was used. Digestion method was carried out following the method of Thompson and Walsh (1983) and WMO (1993)for airborne samples.

2. Monitoring instruments

2.1. TSP, PM₁₀ and PM_2.5(Particulate matter Less Than 2.5 micrometer)

With increased awareness of environmental pollution from fine particulate in the workplace and increasing enforcement of Control of Substances Hazardous to Health (COSHH) and environmental legislation, the demand for more area and perimeter monitoring on a short to medium term basis is on the increase. This need for real-time particulate information is a requirement in general industry, when looking at Total Suspended Particulate (TSP), and at inhalable and respirable dust levels as a health issue.

CASELLA CEL has introduced the Dust Detective Static Air Sampling (SAS) enclosure for exactly this application. This accessory provides a simple solution to short to medium term fixed area monitoring with the micro dust pro and Apex sampling pumps and is designed specifically for use in indoor applications, but some short term outdoor perimeter samples can be undertaken with the unit (Ashraf, 2013).

The key component to this accessory is the sampling inlet which utilizes Polyurethane foam (PUF) size-selective filter techniques. The foam filter specifications and dimensions determine the desired aerosol size selection characteristics and eliminate particle sizes greater than PM₁₀, PM_2.5 or Respirable (4 mm) as appropriate. The larger particles become trapped and collect within the foam matrix, whilst all particles below these “cut-off points” pass through the PUF filters and enter the measurement chamber, where the real time mass concentration is established (Ashraf, 2013).

 After passing through the Micro dust pro, particulate matter is deposited on a 25 or 37mm filter which may be used for gravimetric or chemical analysis.

2.1.1.Starting a Sample Run

 The following procedure was applied:

1.  The protective dust cap was removed and the sample was fit inlet tube/head to the case.

2. The PUF filter foam (s) was inserted and in line sample filter.

3. The Micro dust pro was switched and Apex pump on.was confirmed zero using the in-line filter connected to the sample inlet.

4. The Apex flow was checked that rate was set to 3.5L/min.

5.The unit was located in required location.Pump and Microdust data logger was started according to their respective user manuals.

2.1.2 GPS             

Global Positioning System (GPS) device was used to determine the measurement locations on Alexandria map.

2.1.3 Digital Camera

Digital camera has been used to document measurements and monitoring  the nature of the surrounding environment.

2.2 Data Sources

2.2.1 Metrological Data

Several websites were used to get recent weather data in measurement sites such as Weather Underground (http://www.wunderground.com/)and the Iowa Environmental Mesonet (IEM) (http://mesonet.agron.iastate.edu/).

2.2.2 Calculation Methode for TSP (Total Suspended Particulate) and PM₁₀ (Particulate Matter Less Than 10 Micrometer).

The level of Total suspended particulate(TSP) and the level of respiratory particles(PM₁₀) at the three selected locations was calculated as showen :{(Average of TSP before- Average of TSP after new filter)/ AQL}*100, and the same equation for PM₁₀ :{(Average of PM₁₀ before- Average of PM₁₀ after new filter)/ AQL}*100,the AQL( Air Quality Limit) for air pollutant according to law 4/94 which modified to law 9 for 2009 (Egyptian Environment Affairs Agency,1994).

2.3. Sample preparation:

We washed the collected samples (leaves, stems and roots of the two shrubs) with distilled water to clean dust and deposited substance we recorded the fresh weight for every collected sample, after that all samples were dried on papers then oven dried at 70Cº for 48 hours to constant mass, after putting them  in paper bags. After washing the samples we kept the leachates water obtained from the washed samples in jars to determine heavy metals as it’s content described by Haswel (1991).

The samples of water of all plant part leachates of both shrubs (Nerium oleander and Pittsporum tobira) were washed with it which were put in  jars (18 jars) and were given a code for  doing chemical analysis as determination of heavy metals especially (Cd, Zn and Pb) by using the Atomic Absorpation Spectrometer.

2.4. Soil analysis:

Soil samples of shrubs understudy were taken at random from surface 0-30 cm and at depth 30-60 cm, dried in the oven for determination of  heavy metals (Cd, Zn and Pb), these samples were digested as follows:

- A sample of soil was dried very well and was siftted with sieve it’s scale 2mm.

- A weight was taken from the soil about 0.5g.

- 4ml of Nitric acid was put for the sample (HNO₃).

- 1ml of Prochloric was put for the sample (HCLO₄).

-  The solution was headted at 105º for 2-3 hour until appear white fumes then  the temperature was raised to 185º until the solution became dry.

- The residue was left to be cool then 2 ml of hydrcloric acid (HCL) was added then was heated on 60ºfor one hour.

- The mixture was cooled and 8ml of distill water was added then was left for 4 hour after that was nominated and was continued to 50 ml of distill water to be ready to take the reading from the apparatuse.

- After that the digested sample of soil was taken for doing chemical analysis as determination of heavy metals especially (Cd- Zn and Pb) determination using Atomic Absorpation Spectrometer according toIsaac and Kerber (1971).

Correlation relationships were statisticaly analysed by Gomez and Gomez (1984),in order to detect the relationships among the three pollutants (Pb, Zn and Cd) each of TSP (Total Suspended Particulate) and PM₁₀ (Particulate Matter Less Than 10 micrometer).

RESULTS AND DISCUSSION

1. Heavy metals (lead, cadmium and zinc) content in soil

Data presented in Table (1) showed that, in season 2015, for the Nerium and Pittsporum plants,it was found that the concentration of lead element was the highest in the Dekhela region soil compared with other areas, while lead element was manifested in higher concentration in the layer of 30-60 cm compared with the layer of 0-30 cm. The lowest amount was accumulated in Antoniadis garden in the same depth. Also, it has been found that the concentration of cadmium element was the highest in the Dekhela region compared with the other areas, while cadmium element was found in higher concentration in the layer of 30-60 cm compared with the layer of 0-30 cm. The lowest concentration was accumulated in Antoniadis garden in the same depths. In addition, the concentration of zinc element was the highest in the Dekhela region compared with other areas, while zinc element was obtained of a higher concentration in the layer of 30-60 cm compared with that of the layer of 0-30 cm. The lowest amount was accumulated in Antoniadis garden in the samples taken from the same depth. Some limited differences among the three pollutants with respect to their concentration in spring and autumn. It is believed that these differences might due to the traffic density.

Table (1). Heavy metals (lead, cadmium and zinc) content in the soil planted with Nerium and Pittsporum in the different locations.

D1: soil sample at depth of 0-30 cm.

D2: soil sample at depth of 30-60 cm.

2. Heavy metals (lead, cadmium and zinc) content in water

Data presented in Table (2) displayed the level of lead in leachates samples resulted from washing leaves, stems and roots of the two shrubs (Nerium oleander and Pittsporum tobira) in the spring and autumn seasons of 2015. It was found that high concentration of lead in leaves growing at region of Dekhela compared for concentration the low in Antoniadis garden. With respect to the leachates level of lead in stems, high level was found in Dekhela region, relative to that obtained from Antoniadis garden. The leachate of roots for the both shrubs (Nerium oleander and pittsporum tobira) showed that high concentration of lead was found in Dekhela region vs. the lowest concentration was found in Antoniadis.

With respect to level of cadmium in the leachate leaves, stems and roots of both two shrubs (Nerium oleander and Pittsporum tobira) in the spring and autumn season of 2015, the highest concentration of cadmium was detected in leaves of the shrubs growing at Dekhela region, while concentration was found in those growing at Antoniadis garden. The level of lead in leachate of stem showed also the high level of cadmium in Dekhela region, while the lowest level was found in Antoniadis garden. The leachate of roots of both shrubs (Nerium oleander and Pittsporum tobira) displayed the highest concentration of cadmium in roots of shrubs growing at Dekhela region as it compared with those indicated at Antoniadis garden.

As for the zinc concentration, it was found that the level of zinc in leachates of leaves, stems and roots of (Nerium oleander and Pittsporum tobira) shrubs in the spring and autumn season of 2015,the highest zinc level was obtained in leaves of the shrubs growing at region of Dekhela, compared with that obtained at Antoniadis garden. The level of zinc in the leachates of stems showed also that the highest level of zinc was found in stems of shrubs growing at Dekhela region, while the lowest level was found in those of shrubs growing at Antoniadis garden.The leachates of roots of both shrubs (Nerium oleander and Pittsporum tobira) showed that highest concentration of zinc at Dekhela region compared to those at Antoniadis garden. Some limited differences among the three pollutants with respect to their concentration in spring and autumn. It is believed that these differences might due to the traffic density.

Table (2). Heavy metal content in leachates of plant parts (mg/l).