June 2010, Volume 4, No.4 (Serial No.29)

Journal of Life Sciences, ISSN 1934-7391, USA

Application of Phytoindication Method for Controlling Air Pollution in Yerevan, Armenia

Gayane S. Nersisyan and Hasmik A. Hovhannisyan The Center for Ecological-Noosphere Studies, the National Academy of Sciences of the Republic of Armenia, Yerevan 0025, Armenia

Received: April 12, 2010 / Accepted: May 24, 2010 / Published: June 30, 2010.

Abstract: The research aimed to apply phytoindication for controlling air pollution with chlorine and lead in Yerevan. The research was performed between 2005 and 2008. 5 arboreous species were studied: Robinia pseudoacacia L., Fraxinus excelsior L., Populus alba L., Morus alba L. and Vitis vinifera L.. The research showed that arboreous plants growing in the city accumulate chlorine and lead. Chlorine concentrations in all 5 species varied from 0.50% to 1.77%, and the maximum value was found in Robinia pseudoacacia L., exceeding the control by 3.6 times. As for the level of lead in plants, the concentration varied between 1.64-7.65 mg/kg, and the maximum rate exceeds the background (2.0 mg/kg) by 3.8 times. The authors produced a schematic map of chlorine distribution all over the city territory, and detected the most polluted zones. According to the data the authtors collected, only 3 of 5 studied species displayed high intake rate and tolerance to lead and chlorine pollution: Robinia pseudoacacia L., Fraxinus excelsior L. and Populus alba L. Thus, the authors advise these species for planting in Yerevan. The results of this research were used by the Municipality of Yerevan for functional tree planting in the city.

Key words: Phytoindication, air pollution controlling, chlorine, lead, plants, leaves, Yerevan.

1. Introduction One of atmospheric pollutants is known to be chlorine and its compounds, originating predominantly Air pollution with diverse toxicants on Armenia’s as a result of operation of chemical plants and urbanized sites has been intensifying as a result of incineration of domestic refuse. Studying environmen- industry development and the increasing amount of tal pollution with this biogenic and at the same time vehicles. Besides, the area of pollution zones has extremely toxic element is essential to Yerevan, increased for recent years. Accumulation of diverse because a scientific and industrial enterprise (SIE) toxicants has also been detected in crops cultivated on “Nairit” operates on its territory and produces the territory of Yerevan and its vicinities. [1, 2] chloroprene-synthetic rubber and other chlorine- Lead is known to be one of basic components of containing products. chemical pollution in the urban environment. The main The bioindication method is widely applied in source of lead pollution in Yerevan is vehicles. In different countries and is the best and cost-effective recent years the traffic in the city has become one to control ambient air pollution with diverse increasingly heavy, and this makes it necessary to toxicants. Plants are known to be a very sensitive continuously monitor the contents of environmental Pb testing system for controlling environmental pollution, along with other components of traffic-induced as they take up toxicants not only from soils via root emissions. [2] system but also from the atmosphere via leaves. [3-5] This research covered a period from 2005 to 2008. Corresponding author: Gayane S. Nersisyan, junior researcher, research fields: geoecology, plant biochemistry, Its goal was to apply phytoindication for controlling air phytomonitoring and phytoindication, agro- chemistry. E-mail: pollution with chlorine and lead in Yerevan. To reach [email protected].

Application of Phytoindication Method for Controlling Air Pollution in Yerevan, Armenia 53 it, the following research tasks were set forth: major part of the city lies in the zone of mean (1) Revealing tree species for phytoindication of the concentration of chlorine (0.009-0.019%). However, chlorine air pollution in Yerevan; the authors also found out that plants accumulate (2) Assessing and mapping the chlorine pollution of chlorine, which proves the presence of the element in the city territory using the revealed indicator plants; the ambient air of Yerevan. Chlorine concentration (3) Monitoring the dynamics of Pb pollution in varied between 0.5% and 1.77% in all the 5 studied plants; species, and maximal values exceeded the control (4) Indicating arboreous species tolerant to lead and (0.5%) by 3.6 times (Table 1). chlorine for planting in Yerevan. A three-year long study of the dynamics of chlorine in plants showed some decrease of its average 2. Experiment concentration in 2007; however, maximal concentration The research was performed during the period from of the element remained high especially in leaves of 2005 to 2008. The studied objects were the leaves of 5 Robinia pseudoacacia L. The authors didn’t observe arboreous species: Robinia pseudoacacia L., Fraxinus any drastic differences of chlorine concentration in excelsior L., Populus alba L., Morus alba L. and Vitis Morus alba L. and Vitis vinifera L., its level remained vinifera L. Sampling was done from 80 points all over almost unchanged in 2005-2007 in all the sampling the city in the middle of vegetation period, in July. points. This along the fact that these species are fruit Collected samples were transported to the lab, washed bearing, supports a conclusion that they are unsuitable with tap water and dried at room temperature, then for bioindication and biomonitoring purposes. grounded and decomposed in microwave oven. Pb Afterwards, the authors selected 3 decorative species concentration was determined through the electrothermic widely spread in Yerevan (Robinia pseudoacacia L., atomization method on an AAnalyst 800 (Perkin Elmer, Fraxinus excelsior L. and Populus alba L.) for USA) atomic-absorption spectrometer. The obtained approbation of the phyto-indication method. It should data was processed, tabulated and plotted, afterwards be noted that such a selection was fully justified by the collated with those on the Pb background concentration authors’ previous research which proved that those in the plants. were efficient test systems to monitor heavy metal Samples for chlorine were collected from 35 pollution of the city. [2, 7] different points throughout the city, while the control Fig. 1 shows an average concentration of chlorine in samples were collected at 50 km distance northeastward the leaves of the species for all the studied points. As of the city. Chlorine analysis in plants was run through indicated, all 3 species absorbed and accumulated the method of titration with Ag(NO3). [6] chlorine. Most studied points displayed excessive A schematic map of chlorine concentration in concentration vs. the control. Maximal concentration vegetation was produced using a basic digitalized of chlorine in the leaves of Robinia pseudoacacia L. topographic map (1:10,000) and ArcGIS software. exceeded the control by 1.5-3.6 times, and in the leaves 3. Results and Discussion of Fraxinus excelsior L. and Populus alba L. - by 1.45-2.2 times. The study indicated that of all those 3.1 Chlorine species it was Robinia pseudoacacia L., which had the Alongside with research on plants pollution, we’ve best absorption properties (Fig. 1). The schematic maps also investigated the concentration of lead and chlorine the authors produced on a basis of the obtained data in city soil. Results of the latter indicated that those indicate that the major part of the city lies within the pollutants don’t exceed the control (0.02%) and that the zone of average concentration of chlorine (0.64-0.81%).

54 Application of Phytoindication Method for Controlling Air Pollution in Yerevan, Armenia

Table 1 The dynamics of chlorine contents in the leaves of diverse arboreous species in Yerevan (%). Years 2005 2006 2007

Species Min Aver. Max Min Aver Max Min Aver Max Robinia pseudoacacia L. 0.59 1.06 1.64 0.61 0.92 1.35 0.50 0.81 1.77 Fraxinus excelsior L. 0.47 0.95 1.77 0.59 0.75 0.99 0.43 0.61 1.09 Populus alba L. 0.51 0.84 1.21 0.55 0.80 1.16 0.46 0.70 1.12 Morus alba L. 0.62 0.91 1.48 0.63 0.83 1.00 0.65 0.88 1.22 Vitis vinifera L. 0.50 0.81 1.39 0.52 0.77 1.35 0.49 0.78 1.34

2.0 R. ps eudoacacia 1.8 F. excelsior 1.6 P. alba Control 1.4

1.2

1.0 C (%) 0.8

0.6

0.4

0.2

0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Sampling points Fig. 1 Average concentration of chlorine in plants.

High concentration zones were the south and portion of traffic-induced emissions that contain Pb. southwest parts of Yerevan, where the major sources of Soil studies performed in Yerevan between 2004 and chlorine are situated: SIE “Nairit”, Water Cleanup 2008 indicated that Pb contents decreased by 3.2 times, Station and the municipal refuse disposal site. The whereas average values varied between 25-50 mg/kg authors also found out some local pollution sites in the showing no excess vs. the background (40 mg/kg). [1, direction of the wind rose. That is especially clearly 8] seen on the example of Robinia pseudoacacia L. (Fig. The obtained results showed that for the studied 2). period the background contents of Pb in the samples Phenological surveys allowed indicating of high varied between 1.5-2.5 mg/kg dry matter, so we used ecological tolerance of Robinia pseudoacacia L. and the average value 2.0 mg/kg. Average concentration Fraxinus excelsior L.: even in strong pollution zones varied between 1.64-7.65 mg/kg, thus notably exceeding they looked good and behaved as efficient phytofilters. the background. The obtained data evidence that all the All this evidences that these species can be widely used 5 studied arboreous species take up Pb predominantly to control air pollution with chlorine-containing from the atmosphere but only 3 of them, Robinia compounds and for phytomelioration purposes. pseudoacacia L., Populus alba L., and Fraxinus excelsior L., display high intake rate and tolerance to 3.2 Lead lead. So below is shown the data on the noted 3 Both soil and vegetation tend to accumulate the major species only.

Application of Phytoindication Method for Controlling Air Pollution in Yerevan, Armenia 55

Fig. 2 A schematic map of chlorine distribution in Yerevan (Robinia pseudoacacia L. database).

9 Min. Max. 8 Mean Background 7

6

5

4 C (mg/kg) 3

2

1

0 Robinia pseudoacacia Populus alba Fraxinus excelsior Fig. 3 Pb contents in the leaves of Robinia pseudoacacia, Populus alba and Fraxinus excelsior.

56 Application of Phytoindication Method for Controlling Air Pollution in Yerevan, Armenia

16

14 Fon C

12

10

8

C mk/kg 6

4

2

0 Robinia Populus alba Fraxinus Robinia Populus alba Fraxinus pseudoacacia excelsior pseudoacacia excelsior 1990-1996 2006-2008 Fig. 4 Monitoring data on Pb concentration in the leaves of plants.

Fig. 3 gives minimum, maximum and average values - 2.8 times lower. So the excesses vs. the background of Pb concentration in the leaves of the 3 species; made 2.6, 2.2, and 2.35 times respectively (Fig. 4). average contents were 2.15, 2.36 and 2 times excessive Thus, Pb concentration for the last decade decreased, vs. the background respectively; maximum values being however high vs. the background. varied between 6.7-7.63 mg/kg, and were 3.35-3.8 This phenological studies showed that under times excessive vs. the background (2.0 mg/kg) (Fig. conditions of Yerevan all the three species, particularly 3). Fraxinus excelsior L., are Pb-tolerant and perform The research indicated that the highest contents of sanitary and hygienic functions. All this supports a Pb was in the leaves collected from the central and conclusion on suitability of the trees for functional southern parts of the city, and the obtained values are planting on the whole territory of Yerevan and in the justified by heavy traffic and operation of some vicinities of highways in particular. industrial plants. Besides, city’s waste disposal site is 4. Conclusions in the south, and Pb contents in its vicinities were as follows: 4.36 in Robinia pseudoacacia L. and 5.0 The obtained results evidence that the phytoindication mg/kg in Fraxinus excelsior L.- respectively 2.18 and method can be used to control ambient air pollution 2.5 times excessive vs. the background. Pb concentration with chlorine and lead in Yerevan. in the leaves of trees along highways in the east and This research enabled us to conclude that: north of Yerevan was rather high. (1) Chlorine and lead accumulate in the leaves of Monitoring data on Pb concentration in the leaves of arboreous plants growing in the city, and the major the three arboreous species for years 2006-2008 were portion of them enters the plants from the atmosphere; collated with those for 1990-1996. (2) Distribution of high concentrations of toxicants The results indicated a decrease of both the throughout the city depends on nearness of pollution background and average contents of Pb in all the three sources, rose wind and vegetation species; species for recent years. The average contents between (3) The best chlorine absorption and phytomelioration 2006 and 2008 were as follows: in Robinia property as well as ecological tolerance under pseudoacacia L. - 3.7 times lower than in 1990s; in conditions of chlorine pollution is typical of Robinia Populus alba L. - 1.7 times lower; Fraxinus excelsior L. pseudoacacia L. and Fraxinus excelsior L.;

Application of Phytoindication Method for Controlling Air Pollution in Yerevan, Armenia 57

(4) It is advisable to use the leaves of Robinia [2] H.A. Hovhannisyan, G.S. Nersisyan, A study of lead pollution of vegetation in Yerevan (Armenia), in: Book of pseudoiacacia L. as a test system for bioindication and Proc. of 5th Int. Conf. “Environmental Accounting- biomonitoring of chlorine pollution of the air basin of Sustainable Development Indicators”, Prague, Czech Yerevan; Republic, Apr. 23-24, 2009, p. 7. (5) The high Pb tolerance displayed by Robinia [3] W.J. Manning, W.A. Feder, Biomonitoring Air Pollutants with Plants, Appl. Sci. Publ. Ltd., London, 1980, p. 140. pseudoacacia L., Populus alba L., Fraxinus excelsior [4] R. Schubert (Ed.), Bioindication of Pollution of Terrestrial L., allows to use these species both as testing systems Ecosystems, Mir, Moscow, 1988, p. 350. (in Russian). and efficient phytofilters to reduce Pb pollution of [5] A. Kabata-Pendias, Trace Elements in Soils and Plants, urban and highway-adjacent sites. Warszawa, Poland, 2001, p. 432. [6] H.N. Pochinok, Methods for Biochemic Analysis of Plants, Finally, the results of this research were used by the Naukova Dumka, Kiev, 1976, pp. 27-28. (in Russian). Municipality of Yerevan for functional tree planting in [7] S.H. Arevshatyan, H.A. Hovhannisyan, A.H. Muradyan, the city. M.H. Avetisyan, I.A. Navasardyan, Biogeochemical peculiarities of Fraxinus excelsior under conditions of References pollution of Yerevan with heavy metals, Sci. Reports of Yerevan State Univ. 1 (192) (2000) 114-120. (in Russian). [1] H.A. Hovhannisyan, Ecological monitoring of vegetables [8] A.K. Saghatelyan, The Peculiarities of Heavy Metals grown in urban sites, Electronic J. of Natural Sciences, Distribution on Armenia’s Territory, Edition of CENS National Academy of Sciences RA 2 (3) (2004) 10-13. NAS RA, Yerevan, Armenia, 2004, p. 154. (in Russian).