Directory UMM :Data Elmu:jurnal:J-a:Journal of Asian Earth Science:Vol18.Issue5.2000:

Salix acmophylla, Tamarix smyrnensis

and

Phragmites australis

as

biogeochemical indicators for copper deposits in ElazõgÏ, Turkey

Zeynep OÈzdemir

a,

*, Ahmet SagÏõrogÏlu

b

a

Environmental Department, Mersin University, Mersin, Turkey b

Geology Department, Firat university, ElazõgÏ, Turkey

Received in revised form 6 August 1999; accepted 15 September 1999

Abstract

The ¯ora of Maden C°ayõ valley grows in a soil medium which is heavily contaminated with Cu, Fe, Mn, Zn and other metals

derived from waste discharges to the Maden C°ayõ (stream) from the Maden Cu Mining works. Soil, water and plant samples

were collected from 47 sites (mostly along the Maden C°ayõ valley) and analysed for copper. In all the plant species, Cu was

concentrated more in the twigs of the plants than in their leaves and ¯owers. Correlation coecients (r) were calculated for the correlation between the concentrations of Cu in the twigs of plants and those of the corresponding soil. Statistics of correlation were as follows:Salix acmophylla r= 0.93 (n= 19,P< 0.01),Tamarix smyrnensis r= 0.93 (n= 20,P< 0.01) andPhragmites australis r= 0.72 (n= 18, P< 0.01). Salix acmophylla, Tamarix smyrnensis and Phragmites australis are therefore good indicators of the copper concentrations in the soil and these species could be successfully used for biogeochemical prospecting. These species are typical and common species of the semi-arid Anatolian climate. 7 2000 Elsevier Science Ltd. All rights reserved.

1. Introduction

Biogeochemical methods of prospecting involve the chemical analysis of vegetation in order to detect min-eralization in the underlying substrate (Go€ et al., 1985). There are probably more plant indicators for copper than for any other element and the reputation of such indicators has, in some cases, been established for over a century (Brooks, 1979). The literature on this topic includes papers by Yates et al. (1974), Chaf-fee and Gale (1976), Brooks et al. (1978, 1995) and Tiagi and Aery (1986).

The Maden C°ayõ valley is situated 70 km southeast

of ElazõgÏ and crosses the township of Maden (Fig. 1). The area is mountainous and thinly-populated. Veg-etation is sparse and only stream valleys are conducive

to plant growth. The climate is typical semi-arid conti-nental (hot and dry summers, cold and rainy winters).

This area is famous for its Cu and Cr deposits. The copper mines of Maden Anayatak have been exploited since 2000 B.C., and with modern methods since 1939. Overburden, slags, ¯otation wastes and ground waters

from the mine are discharged into the Maden C°ayõ

(stream) without any treatment. Therefore, the plants in the valley of the stream have grown in an environ-ment heavily contaminated with metals. Plants that grow in such an environment should be able to maxi-mize metal content and from their analysis it should be possible to determine the optimum plant species for biogeochemical prospecting. The plants of the Maden

C°ayõ valley are a common species of Anatolia and a

promising species used extensively for prospecting (OÈzdemir, 1996). This study investigates Cu concen-trations in soil, water and di€erent organs of plants of the Maden C°ayõ valley. The aim was to determine the

plant species that concentrate high amounts of Cu in their organs. The approach was to collect water, soil

1367-9120/00/$ - see front matter72000 Elsevier Science Ltd. All rights reserved. PII: S 1 3 6 7 - 9 1 2 0 ( 9 9 ) 0 0 0 6 5 - 6

and plant samples from 47 sites and analyse them for Cu. Analytical data were to be evaluated and the species with high plant/soil correlation values deter-mined.

2. Geology

The Maden area is situated in the Southeastern Thrust Belt, a geotectonic unit a€ected by south±north compression and characterised by many north-dipping thrust zones (according to Aktas° and Robertson, 1984;

``imbricitic zone'').

The geology of the Maden area can be summarized as follows: Two geological units cover most of the area. These are: Guleman Ophiolites and Maden Com-plex (Fig. 2). Guleman Ophiolites are composed of peridotites, gabbros, sheeted dykes and pillow lavas and bear many alpine-type chromite bodies. Emplace-ment age of the ophiolites is estimated as Upper Cre-taceous. The Eocene Maden Complex unconformably overlies the ophiolites. The complex is composed of rocks that are sedimentary (sandstone, marl, limestone, mudstone), volcano±sedimentary and volcanic±subvol-canic (diabase, diabase breccia, andesite and basaltic andesite). The main volcanic bodies are products of submarine volcanism and hosts for Cyprus Type pyri-tic copper deposits (Bamba, 1976; Aktas and Robert-son, 1984; UÈstuÈntas° and SagÏõrogÏlu, 1993).

The investigated area is situated across the Maden township of ElazõgÏ province in Eastern Turkey (Fig. 1).

Maden C°ayõ (stream) cuts across the whole Maden

area and therefore is the most important discharge passage. The area has very rough morphology where peaks around 1500 m high are separated by deep val-leys with mainly seasonal streams. Having a semi-arid inland climate, the area is poorly vegetated and the vegetation is con®ned to stream valleys only.

3. Materials and methods

Samples were collected along the Maden C°ayõ valley

(Fig. 2) and at places with similar lithologies but with-out any pollution. Forty sites were selected: 36 along the Maden C°ayõ valley (®ve sites before a discharge

point and 31 sites after the discharge), one at Sordar

C°ayõ valley, and three in Malatya provice (150 km

northwest of Maden town). During 1993 (sample num-bers; 21, 22, 23), 1994 (31, 32, 33) and 1995 (41, 42, 43) more than 300 plant tissues (as twigs, leaves, ¯ow-ers) of 42 species were collected at these sites. Plants were identi®ed by reference to the work of Davis (1965±1985). At each site, a soil sample was collected from a depth of about 20±25 cm, soils were screened and the 2 mm fractions taken. In order to eliminate e€ects of metal enrichment from rotten leaves and coarse slag particles, the water samples were ®ltered and then placed in 1 l polyethylene bottles and 3 ml of

concentrated HNO3 was added to avoid precipitation

of dissolved ions.

Dried plant samples (2.00 g) were placed in porce-lain crucibles and reduced to ash in a mu‚e furnace

with a 508C/h increase rate over 10 h at a maximum

temperature of 5508C. Ashed samples were cooled and

weighed. Nitric acid (1:1) was added to the ash at 5 ml per sample and then evaporated in an oven. The resi-due was redissolved in 5 ml of 6 M HCl and diluted to 25 ml by adding deionized water. The solution was analyzed for Cu with a Flame Atomic Absorption Spectrophotometer (324.5 nm; PU 9100X Philips). The method used was as described by Benton and Jones (1984) and Rose et al. (1979).

Dried soil samples (0.100 g) were placed in

polyethy-lene crucibles and 10 ml of concentrated HF+HNO3

(1:1) mixture added and the sample heated in a water bath until dry. After the evaporation 7 ml of HCl (1:1) was added and the evaporation was repeated. The resi-due was dissolved in 7 ml of 6 M HCl and diluted to 25 ml by adding deionized water (Brooks et al., 1992; Rose et al., 1979). At least four solutions were pre-pared and analyzed from the same sample and mean values were taken. The solutions were analyzed as for Cu, Mn, Fe and Zn with a Flame Atomic Absorption Spectrophotometer (324.5; 279.5; 248.3 and 213.9 nm, respectively). The water samples were analyzed for Cu

directly by Flame Atomic Absorption Spectropho-tometry (Rand, 1975).

4. Results and discussion

The Cu concentrations of stream water were <0.02 ppm (mg/ml) in the samples collected at locations 28, 27, 26 (unpolluted Maden stream waters) and 34 (<0.02 mg/ml, water of the Sordar stream). Samples from the discharge point (location 31) contained

2.7 mg/ml Cu and decreased to 1.0 mg/ml at location

33 and <0.02mg/ml at locations 21 and 43. GuÈr et al. (1994) found that the Cu concentration in the Maden valley has changed from 0.015 to 1.62 ppm during 1 year. The high Cu values of Maden valley are due to pollution from overburden, slags, ¯otation wastes and metallic waters from the mine.

The soil samples from the locations above the

dis-charge point had Cu values from 72±250 mg/g. These

values are higher than expected background values for such lithologies (average for basic volcanics is 85 mg/g, Rose et al., 1979), perhaps due to mineralization and airborne pollution from the manganese smelting plant.

Samples from the Sordar stream valley contained 512

9 mg/g Cu and this can be taken as background value

for the Maden area (OÈzdemir, 1996). The Cu concen-tration of soil samples from the Kralkõzõ dam area,

30 km down stream in the Maden C°ayõ Valley,

aver-aged 66 mg/g. The Cu concentration of soils of similar

geological environment in Malatya province are

between 15 and 50mg/g. The value of about 35mg/g is considered background for the area. The Cu content of soils along the Maden C°ayõ valley was the highest

(range of 230 to 6646 mg/g) at site 32, the closest

(500 m approx.) plant sample site to the discharge

point. The Cu concentration was 1920299 (standard

deviation of the mean for three samples) mg/g at site 44 and 699279 at site 35. As can be seen from Fig. 3

there is a decline in Cu concentrations from the dis-charge point.

The Cu concentrations of plants which were rare (n

< 4) at the sample sites have been excluded from this study. Species for which there were more than four samples were evaluated on the basis of the Cu contents of their leaves, ¯owers and twigs.

Among leaves, twigs and ¯owers, the twigs com-monly had the highest Cu concentrations. In the litera-ture, it was reported that twigs were found to be richer in Cu than leaves (Yates et al., 1974; Tiagi and Aery, 1986; OÈzdemir, 1996). Therefore, soil±plant Cu content relations were studied on the basis of the Cu contents of twigs. The Cu contents of twigs can be as high 1250 ppm (Rubus sanctusSchreber; OÈzdemir, 1996).

The Cu concentrations in leaves, twigs and ¯owers, and in associated soils are given in Table 1. Data for the statistical signi®cance and correlation coecient values of the plant/soil relationship for copper are pre-sented in Table 2.

As can be seen from Fig. 4, the best plant±soil cor-relation is for Salix acmophylla Boiss (r= 0.93, P< 0.01). Another high plant±soil correlation exists for

Tamarix smyrnensis Bunge (r = 0.93, P < 0.01) in Fig. 5. For Phragmites australis(Cav) Trin. ex Steudel the corresponding values (Fig. 6) are; r= 0.72, P< 0.01. Therefore they may act as very suitable tools for biogeochemical prospecting.

The highest Cu concentrations in indicator plants at

Fig. 3. Copper in soils along the Maden C°ayõ valley (see Fig. 2 for the locations of sample sites).

Table 1

Copper concentrations in various plants and their organs, and in soils from Maden C°ayõ valley and similar geological environments (Malatya, Sordar C°ayõ and Kõralkõzõ dam)

M, S and Ka Maden C°ayõ Valley

Plant species Sample number Range Cu in soilmg/g Range Cu in plantmg/g Range Cu in plantmg/g

Salix acmophylla

Leaves 19 77±196 87±227

Twigs 19 81±1024 85±170 149±402

Flowers 9 28±321 160±450

Salix alba

Leaves 9 144±525 77±113 100±187

Twigs 9 104±386 151±591

Platanus orientalis

Leaves 20 81±1920 37±360 46±358

Twigs 20 102±300 90±369

Tamarix smyrnensis

Thin twigs 22 81±1024 18±251 16±151

Twigs 20 24±269 110±780

Flowers 17 62±469 22±56 73±550

Phragmites australis

Leaves 17 73±745 15±88 25±261

Twigs 18 25±57 72±483

Flowers 7 91 75±2423

Populus nigra

Leaves 14 73±1024 47±357 119±274

Twigs 14 103±386 85±533

Vitis sylvestris

Leaves 14 250±1920 62±231 110±198

Twigs 14 114±271 99±382

Elaeagnus angustifolia

Leaves 13 81±502 40±297 156±446

Twigs 13 206±478 80±683

Rubus sanctus

Leaves 8 15±51 140±204 171±462

Twigs 8 194±333 181±257

Robinia pseudoacacsia

Leaves 11 81±409 120±216 49±293

Twigs 11 128±153 133±320

Artemisia vulgaris

Leaves 8 81±302 115±218 35±253

Twigs 8 192±236 129±215

Rumex crispus

Leaves 7 109±502 89 195±500

Twigs 7 246 115±338

Salix armenorossica

Leaves 9 81±699 55±77 66±295

Twigs 9 126±100 73±342

Anchusa azurea

Leaves 8 81±1920 83±119 35±100

Twigs 8 97±67 100±216

Carex acuta

Leaves 7 109±1920 329±179 34±997

Twigs 7 162±324 74±318

Xantum strumoisa

Leaves 9 30±63 85±142 52±425

Twigs 9 126±133 55±233

a_{M, S and K: Malatya, Sordar C}

the discharge point (the Cu concentration in soil was

6643 mg/g site 32) were 590, 780 and 560 mg/g for

Salix acmophylla, Tamarix smyrnensis and Phragmites australis, respectively. The Cu concentration of these plants in a similar geological environment in Malatya

province were 119, 36 and 27 mg/g for Salix

acmo-phylla, Tamarix smyrnensis and Phragmites australis, respectively. These values are considered background for the area.

In addition to the above mentioned species, there

were no signi®cant plant±soil correlations for Salix

alba L., Platanus orientalis L., Populus nigra L., Vitis sylvestris Gmelin, Elaeagnus angustifolia L., Rubus sanctus Schreber, Robinia pseudoacacia L., Artemisya vulgaris L., Rumex crispus L., Salix armenorossica

A.Sky, Anchusa azurea Miller, Carex acuta L. and

Xantum strumoisaL.

In all the species, metal uptake decreases with the increasing soil metal contents. Therefore, in this work, plant/soil metal concentration quotients are

more important. Copper in the twigs of Tamarix

smyrnensis, Salix acmophylla and Phragmites

austra-lis showed a signi®cant plant/soil relationship.

Inspection of Fig. 7 shows Tamarix smyrnens more

sensitive to Cu than are Salix acmophylla and

Phragmites australis.

A study of interelemental relationships in vegetation, was prompted by two main considerations. The ®rst was to see if the signi®cance of any relationship found for one element in a plant could be improved by including its interaction with another element. The sec-ond was to examine the degree to which leaves and twigs of a given species have similar amounts of a par-ticular element and could, thereby, be mutually exchangeable in the course of biogeochemical prospect-ing.

Interelemental relationships for pairs of elements in plants and soil are shown in Table 2. The data for soil show that although there is a signi®cant (or very

highly signi®cant) relationship between Cu in Salix

Table 2

Results of correlation analyses for interelemental relationships in soil and indicator plants

Elements in soil

Plant species/element Cu Zn Mn Fe

Salix acmophylla

Fig. 5. The relationship between the concentration of copper in the soil and inTamarix smyrnensistwigs.

Fig. 6. The relationship between the concentration of copper in the soil and inPhragmites australistwigs.

acmophylla, Tamarix smyrnensis and Phragmites aus-tralis, and Fe in soil, there are non signi®cant (P> 0.05) relationships betwen Cu in three of these indi-cator plant and other elements (Zn and Mn) in soil.

It is concluded that the copper content in the twigs of Tamarix smyrnensis, Phragmites australis and Salix acmophylla is a good indicator of the copper content of the soil and these species could be successfully used for further biogeochemical prospecting. These species are quite common in inland Anatolia as well as in Eastern Anatolia.

Acknowledgements

We are grateful to Prof. Dr. B.yõldõz of õ.nonuÈ Uni-versity (Turkey) for o€ering many suggestions and improving the manuscript.

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