Recognition of environmental trace metal contamination using pine needles as bioindicators. The...

Cases and solutions

914 Environmental Geology 39 (8) June 2000 ´ � Springer-Verlag

Recognition of environmentaltrace metal contamination usingpine needles as bioindicators.The urban area of Palermo (Italy)M.G. Alaimo ´ G. Dongarrà ´ M.R. Melati ´ F. Monna ´ D. Varrica

Abstract A total of 43 composite samples of sev-eral years of needle growth from Pinus pinea L.,collected in and around the city of Palermo wereanalysed for major and trace elements by INAAand ICP-MS. The chemical composition of pineneedles suggests that the presence of Pb, Sb and Brin excess with respect to soil composition is due toanthropogenic emissions. The anomalously highvalues of these elements observed in the urban areadecrease outside town. Lead isotope data confirmthe anthropogenic origin of lead. The origin of Znand Cu excess remains uncertain at the moment,although wholly-crustal origin appears doubtful.Morphological alterations attributable to phenolaccumulation, such as modifications in the lengthof mesophyll cells and the appearance of lacunae inthe distal portions, were observed in needles. Theaccumulation of phenols, linked to the presence oflead, gives rise to a specific pattern of metabolitesproviding mechanisms of detoxification and protec-tion, so that the accumulation degree may be pro-posed as a marker of environmental pollution.

Key words Environmental geochemistry ´ Tracemetals ´ Particulate matter ´ Biogeochemistry

Introduction

Analysis of plant material is an effective method of pros-pecting, as pointed out by Goldschmidt (in the UnitedStates) and Vernadsky (in the Soviet Union) in the early1930s, because plants may reveal anomalous metal con-centrations in soils. The same principle may sometimesbe used successfully to assist environmental studiesregarding air quality. Nowadays lichens, mosses and var-ious kinds of plants are frequently used for monitoringenvironmental pollution on local and also on larger scales(Rambaek and others 1980; Nimis and others 1990; Bergand others 1995; Watmough 1997; Kurczynska and others1998). Whereas mosses and lichens obtain most of theirchemical element supplies from dry deposition of partic-ulate matter and wet deposition, the aerial part of someplants may collect metals from the atmosphere as well asfrom soils. Pine needles have succesfully been used asbioindicators to reveal the presence of metal concentra-tions in the environment because of their ability to retaincertain trace elements (Bargagli and others 1991; Bargagli1993; Dmuchowski and Bytnerowicz 1995). Justificationfor use of pine needles also derives from the fact thatconiferous trees are widely distributed in many countriesand may easily be identified even by people who are notexperts or skilled botanists. Satisfactory results can beachieved provided that element concentrations in thesubstrate are sufficiently low and constant to yield asignificant geochemical contrast. A sampling programmeof pine needles (Pinus pinea L.) was carried out in 1998in and around the city of Palermo (Italy) to study thepresence of heavy metals in the atmospheric aerosol andto identify the main sources introducing these metalsinto the environment. The survey was also aimed atinsights into the influence of air pollution on the mor-phological and cytological structure damage observed inpine needles. The main results are described in thispaper.

Geology of the study areaThe city of Palermo is situated on the north-eastern coastof Sicily along the wide bay Piana di Palermo overlookedby Mt. Pellegrino (606 m above sea level). It is delimited

Received: 4 June 1999 ´ Accepted: 24 June 1999

M.G. Alaimo ()) ´ M.R. MelatiDipartimento di Scienze Botaniche, Via Archirafi 40,90123 Palermo, Italy

G. Dongarrà ´ D. VarricaDipart. Chimica e Fisica della Terra (CFTA), Via Archirafi 36,90123 Palermo, Italy

G. DongarràIstituto di Geochimica dei Fluidi, Via U. La Malfa 153,90146 Palermo, Italy

F. MonnaInstitut F.A. Forel, 10 route de Suisse, 1290 Versoix,Switzerland

Cases and solutions

915Environmental Geology 39 (8) June 2000 ´ � Springer-Verlag

at NE by the Tyrrhenian sea and surrounded by moun-tains (Monti di Palermo) elevated 500±1000 m abovesea level. The study area is entirely covered by sedimen-tary rocks. The Monti di Palermo, of Mesozoic andTertiary age, are essentially made up of limestones (Abateand others 1978). Along the perimeter of the Piana diPalermo they overlay turbidite deposits, of Oligomioceneage, made up of clay, marly-clay and marls intercalated

with quartz arenites (Numidian flysch). White or yellowquaternary biocalcarenites occur in the lower and plainportions. Most of the eastern sector of the Piana diPalermo is covered by a bright red-coloured soil rich inFe-oxides, known as Terra Rossa. Palermo has almost 1million inhabitants and is a city where major industrialinstallations are lacking. Potential local pollutants arethus limited to emission from vehicular traffic, house-

Fig. 1Geological sketch map of thestudy area with the location ofthe sampling sites. SamplesA1±A8 fall outside the urbanagglomeration. Carbonaterocks belonging to differentstratigraphic units.

Bioclastic calcarenites.Clay, marly-clay and marl

intercalate with quartz arenites(Numidian flysch).Marly-clay. Old aluvials.

Nappe debris.Palermo centre

Cases and solutions


heating and small manufacturing industries. A geologicalsketch map of the study area, together with the locationof the sampling sites, is shown in Fig 1.

Materials and experimentalmethods

A total of 43 composite samples of several years of needlegrowth from Pinus pineae L. were collected in July 1998.Each sample, made up of several sub-samples collectedfrom all around the tree, was stored in paper bags. Thesamples were dried for 48 h at 40�C and then ground to afine powder. A portion of each sample was analysed formajor and trace elements by INAA (Br, Ca, Co, Cr, Fe, K,La, Mo, Na, Sb, Sc, Sm) and ICP-MS (Al, Mg, P, Sr, Mn,Cu, Pb, Zn) using NBS 1572 and 1632 B as standard ref-erence material. Several replicates yielded a precision inthe ranges 20±30% and 5±10% for trace elements andmain components respectively. A different sample por-tion was used to determine the Pb isotope composition.Approximately 200 mg of needles were totally dissolvedwith 5 ml of concentrated HNO3 (Merk suprapure grade).Digestion was achieved with microwave assistance (MLSETHOS) in pressurized Teflon bombs. Pb isotope ratioswere measured after Pb purification by quadrupole basedICP-MS (HP 4500) following the procedure described inMonna and others (1997, 1998). Blanks were systemati-cally measured and were always negligible in regard tothe total amount of Pb in the samples. The Pb isotopicdetermination in soil samples followed the same pro-cedure described above, except that the total digestionwas achieved with a mixture of 2 ml of each HNO3, HCland HF suprapure grade. Phenols were highlighted intransversal cryosections from mature needles, usingGahan's test (Gahan 1984), with Fast Blue BB 0.08% inacetate buffer at room temperature for 30 min. Phenolswere red or brown in colour.

Mineralogical composition of airborne particlesA previous study on the mineralogical composition ofatmospheric particulate in the urban air of Palermo wascarried out by Alaimo and Ferla (1979), who identifiedcalcite, dolomite, quartz, talc, clay minerals and palygor-skite in aerosol samples. Palygorskite was only occasion-ally found and appeared to be transported as dust fromthe Sahara. Badalamenti and others (1984), in their studyon the chemical composition of rain in Palermo, con-firmed the occurrence of calcite, dolomite, quartz andphyllosilicates.

Results

Inorganic elements in needles and local substratesTable 1 shows a statistical summary of the chemicalconcentrations of macronutrients and trace elementsdetermined in needle samples. It is worth noting that

Tabl

e1

Bas

icst

atis

tica

lpa

ram

eter

sfo

ra

tota

lof

43pi

nene

edle

ssa

mpl

es.

Dat

aar

ein

ppm

(dry

wei

ght)

.C

V%

isth

eva

riat

ion

coef

fici

ent

Al

Ca

FeM

gK

PM

nN

aSc

LaSm

SrB

rC

oC

rC

uM

oPb

SbZ

n

Min

imum

100

1330

011

2017

0012

320

1450

1514

0913

10.0

910

.01

1611

4.3

10.1

10.1

1210

.04

1410

.03

11M

axim

um70

036

650

2200

4600

1585

014

0081

7520

2910

.47

10.0

729

120

10.8

14.4

3812

.50

5017

60A

vera

ge25

319

012

1486

2588

1538

219

1926

2057

1110

.21

10.0

212

132

10.3

11.9

1210

.66

1311

.623

Med

ian

200

1795

014

0025

0014

810

1890

2515

1010

10.2

010

.02

1112

710

.311

.811

10.5

713

11.5

21G

eom

.m

ean

212

1806

913

8325

3215

050

1888

2415

3610

10.2

010

.02

1112

410

.311

.510

10.4

611

10.9

21St

d.D

ev.

(1s

)15

915

399

1435

1569

1222

412

3511

1661

1510

.09

10.0

116

125

10.2

11.0

1710

.56

1911

.519

CV

%16

311

160

1189

1122

1114

111

2644

1181

5043

5548

180

5354

6185

6593

41

Cases and solutions


major elements in soils are also the most abundantelements in pine needles. In particular, Al, Ca, Fe, Mg, K,Na and P generally make up 97% of the weight of theanalysed elements, Ca, Mg and K being the most abun-dant. Geogenic and anthropogenic sources may contrib-ute to the load of metals in needles. The formers includesoil dust, sea spray and direct uptake from soil by roots.The latters are limited to emission from vehicular traffic,house-heating and small manufacturing industries.Table 2 shows the chemical composition of the threesurface soils most typical of the study area: Terra Rossa,Mt. Pellegrino and calcarenitic soils. Lead isotopecompositions in both limestone and flysch of Monti diPalermo, and also in the calcarenite of Piana di Palermoare reported in Table 2.

Cluster analysisA useful and relatively simple method of grouping vari-ables according to their mutual correlation is clusteranalysis. This procedure reveals variables with thegreatest within-group correlation relative to the between-group correlation. A two-dimensional hierarchicaldiagram (dendrogram) is the final product of the cluster-ing procedure. Figure 2 shows the dendrogram structurefor the set of needle data. Here the result of theunweighted pair-group average method (UPGM) ofclustering, in combination with coefficients of correlation,is reported. However, it was found that both unweighted(UPGM) and weighted (WPGM) methods give similardendrogram structures and they provide better groupingsthan single linkage. Correlation coefficients were used assimilarity coefficients because they are best interpretablein terms of geochemical associations. At 0.5r three maingroups of related elements may be identified, Mn, Mgand Na not being linked to any of these. Two clusters are

Fig. 2Dendrogram produced bycluster analysis (UPGM) for43 samples and 18 elements.1-Pearson r values on theordinant scale indicate thesimilarity of geochemicalvariables

Table 2Major and trace elements in three surface soils of the study area. Lead isotope ratios are also reported

Si Ti Al Fe Mn Ca Na P K MG Rb Cs

Calcarenetic soilMt. Pellegrino soilTerra Rossa soil

115424 1160 11059 12098 1177 384504 1742 1175 11332 6394 1<20 1<0.5216741 4200 71720 39376 1084 120512 2522 5237 15525 5791 128 17.4296220 2340 47743 32312 1542 143382 1558 1960 19796 5972 179 14.2

Sr Cr Ni La Ce Nd Sm Eu Yb Lu Sc As


111660 1115 11112 11111.7 111<3 11111<5 1110.4 1110.1 11110.2 111<0.05 1110.4 1<2111110 1180 11145 11154.4 1197 111140 1118.4 1111.5 11113.4 1110.55 112.5 19111181 1155 11122 11132.9 1151 111127 1115.8 1111.1 11112.2 1110.36 119 31

Th Co Cu Pb Sb Zn Br U


11111<0.5 1112 11114 1111<5 111<0.2 111115 1113 1112.0111114.7 1116 11163 11150 1111.3 111193 1151 1112.1111119.1 1113 11145 11169 1111.6 111181 1116 1111.0

Lead isotope 206Pb/207Pb 208Pb/206PbNumidian Flysch 1.197 � 0.006 2.081 � 0.010Mt. di Palermo 1.169 � 0.005 2.096 � 0.008Calcarenites 1.200 � 0.001 2.061 � 0.007

Cases and solutions


related to the mineralogy of the main units constitutingthe lithological background. The first, comprising Ca andSr, is largely influenced by the calcareous substrate ofPalermo. The second cluster, consisting of Al, La, Sm andSc, is also clearly associated with lithology, defining theclay soil component. Zn, Pb, Br, Cu, Cr and Sb aregrouped together, and all of these elements may be indi-cators of anthropogenic sources.

Lead isotope composition in needlesand airborne particles

In environmental studies, lead isotope composition is apowerful tool to identify the sources of emission of thismetal into the atmosphere, or to study the dispersionprocesses. Lead has four naturally occurring isotopes.Three of these: 206Pb 207Pb and 208Pb, derive from thedecay of long-lived 238U, 235U and 232Th respectively,whereas the fourth is the nonradiogenic 204Pb. In WesternEurope, Pb used for human activities totally derives fromremote allochtoneous ore bodies, which are characterisedby their own isotopic compositions (Doe and Stacey1974; Kramers and Tolstikhin 1997). As Pb retains thesignature of the source from which it was extracted, itmay be possible to discriminate the anthropogenic Pbfrom the geogenic and local-derived Pb. Results from anearlier survey (Monna and others 1999) showed that twotypes of anthropogenic Pb can be distinguished in Sicily:Pb added as anti-knock compound in gasoline (206Pb/207Pb : 1.066±1.137; Table 3), and Pb generally used byindustry (206Pb/207Pb : 1.141±1.165). These lead sourcesare isotopically different from the terrains constitutingthe area in and around Palermo (206Pb/207Pb : 1.169±1.200;Table 2). Some needle samples were analysed for theirlead isotope compositions yielding 206Pb/207Pb ratioswhich vary in the range 1.132±1.154 (Table 3). Consid-ering that `industrial' Pb is, with respect to lead fromgasoline, of minor importance, as Palermo lacks anysignificant industrial installations, these values should be

the result of a simple binary mixing between automotiveexhausts and soil minerals (Fig. 3). It is interesting tonote that the needles appear to have received a greatercontribution from soil dust (more radiogenic) than theatmospheric filters previously collected in the centre ofPalermo (206Pb/207Pb ~ 1.106±1.123, typical of leadedgasoline), probably due to the longer exposure time ofthe needles or even to the uptake of a significant partof geogenic Pb by the tree roots.

Discussion

A serious problem in the interpretation of biogeochemi-cal data is being able to distinguish between the origin ofelements which are derived from soil and those arisingfrom anthropogenic sources. The element contents inpine needles are mainly related to the local soils and

Table 3Lead isotope ratios in some selected pine needles samples fromthe study area. Isotope ratios in gasoline (from Monna andothers 1999) are also reported for comparative purposes. Theerrors are given at 95% confidence level

206Pb/207Pb 208Pb/207Pb

Pine needles A1 1.154 � 0.006 2.108 � 0.014A3 1.132 � 0.004 2.125 � 0.008A6 1.148 � 0.005 2.123 � 0.009A7 1.138 � 0.004 2.125 � 0.009A9 1.132 � 0.004 2.121 � 0.008A10 1.144 � 0.006 2.114 � 0.008A11 1.143 � 0.004 2.111 � 0.008A13 1.143 � 0.004 2.106 � 0.008

Gasoline Agip 1.066 � 0.004 2.205 � 0.010Shell 1.137 � 0.006 2.112 � 0.008IP 1.083 � 0.004 2.166 � 0.006

Fig. 3208Pb/206Pb vs. 206Pb/207Pb scatterdiagram

Cases and solutions


particularly to the abundance of mineral species in whichthey are present. Therefore, in order for the contents oftrace elements in needles to be used as indicators of thepresence of these elements in air, the distribution of theelements in local soil must be taken into account.Figure 4 shows the mean concentration of each singleelement in pine needles compared with the distributionof the same elements in the three main lithotypescomposing the soil of Palermo. Each element is thusassociated with three points on the graph. Consideringthe elements of definitely terrigenous origin, it is possibleto delimit the field which includes all the elements whoseorigin is attributable to natural processes of assimilationby plants or to deposition of soil dust on pine needles.Sb, Pb, Br, Zn and Cu plot outside this field. These ele-ments are thus enriched in the needles with respect tothe local substrate and there is a definite correspondencebetween this group of elements and those indicated bycluster analysis as being of anthropogenic nature.Na-enrichment is likely related to sea spray contribution.Allen and others (1974) indicated the normal naturalconcentration of lead in plants as about 3 ppm, whereasAlloway (1968) gave a higher value of 10 ppm. The con-centrations of Pb in needles for 58% of the analysed sam-ples were above 10 ppm, a level higher than normal forthis element with respect to less urbanized areas. Eightneedle samples (A1±8 in Fig. 1) collected outside Palermoyielded a mean concentration of 5 ppm. Therefore,despite its declining use in gasoline, lead is still a signifi-cant urban air pollutant. Bromine, beside being a charac-teristic of marine aerosols, is also emitted in significantamounts by non-catalyst vehicles, as leaded gasoline con-tains brominated compounds added to reduce the for-mation of lead oxides inside the engine. After correctionfor sea spray contribution (Dongarrà and Varrica 1998),

an excess of Br still remains, confirming the importanceof automobile combustion in the dispersion of lead andbromine into the atmosphere. The Pb/Sc and Sb/Sc ratiosobserved in pine needles (~ 262 and 31 respectively),when compared to those observed in the substrates(ranges 4±10 and 0.1±0.3 respectively), indicate that Pband Sb are anthropic in origin.Although Zn and Cu appear to be slightly enriched withrespect to soil, it must be borne in mind that both theseelements are essential for plants. Their concentration inneedles are within the normal natural range (2±20 ppm,with most plants in the range 4±12 ppm) indicated byKabata-Pendias and Piotrowska (1984). Only 4 sampleshad Cu content above 20 ppm and 16 above 15 ppm.However, it should be noted that the order of abundanceof these elements in pine needles corresponds to theobservation of Monna and others (1999) in aerosol sam-ples. Figure 5 shows the areal distribution patterns of Pb,Cu, Zn and Sb. The element distribution shown on themaps exhibits the geochemical anomalies of anthropicorigin within the study area. Metal concentrations arehigher in the urban area and decrease immediatelyfarther inland. The anomalies occupy the whole urbanagglomeration indicating that local sources play a greatrole in the heavy metals pollution.

Morphological and cytological characteristicsof needles

As the excess of certain elements in soils and air canaffect plant morphology, the pine needles were subjectedto microstructural analysis and the accumulation ofsecondary metabolites (phenols), considered as endopro-tective products and bound to cell walls, was also eval-uated (Strack and others 1998; Zobel and Nighswander1991; Bussotti and others 1998). Figure 6 shows the cyto-

Fig. 4Comparison of the meanconcentrations of each singleelement in pine needles withthose in three main lithotypescomposing the soil ofPalermo. The two solidstraight lines delimit the fieldwhich includes the elements ofdefinitely terrigeneous origin

Cases and solutions


histological characteristics of control samples that can becompared with pine needles coming from pollutedstations (Fig. 7). Although the cytohistological character-istics cannot, alone, be considered specific, they do takeon significance as indicators of environmental pollutionwhen correlated with other morphological and biochemi-

Fig. 5Areal distribution maps of Pb, Sb, Cu and Zn in pine needles.Two solid curve lines delimit the urban agglomeration

Cases and solutions


Fig. 7Microscopy image of needle samples from a polluted site.Dense red droplets from phenols located around the resinduct (a) and in the vascular bundles (b) may be observed.Mesophyll abnormal cellular enlargement (c). Phenols fill themesophyll and epidermis cells and also the vascular andtransfusion tissues (d)

Fig. 6Cross section of needle sample from a control site showingthe absence of phenols (a). Mesophyll cells and vascular tissueexhibit a normal enlargement (b)

Cases and solutions


Cases and solutions


cal alterations, such as the accumulation of phenols(Fig. 7a,b) (Zobel and Nighswander 1991; Melati andothers 1997; Alaimo and others 1997, 1998, Bussotti andothers 1998; Melati and others 1998). Experimentally, thedistal portions of the needles were separated from theproximal ones, and transversal cryosections of the twoparts were made. The cytochemical test was applied tohighlight the phenols, which accumulated first in thevacuoles of epidermic cells and of the mesophyll(Fig. 8a). The mesophyll cells of polluted samples appeardisplasic (Fig. 7c,d), full of abundant phenols and inter-digitations between evident intercellular spaces, with finalconcentrations of cytoplasm along the membranes(Fig. 8b). The phenols, later solubilized, are distributed inthe cytoplasm (Fig. 8c,d) and may thus undergo retrans-location towards the external walls of epidermic cells,forming layers between walls and cuticle. The externalwalls of epidermic cells become thickened. Next, phenolsare also observed in the cell components of transfusiontissue and in the two conducting bundles. They werenever observed in endodermic cells (Fig. 8d). Morpholog-ical alterations attributable to phenol accumulation wereobserved, such as modifications in the length of meso-phyll cells and the appearance of lacunae in the distalportions where, as a subpathological event, phenols accu-mulate to a greater extent, just before apical necrosis ofthe needles (Fig. 9a). Vice versa, the damage is not sogreat in the proximal portions where phenols accumulatein small drops and cells appear only slightly displasicand poorer in phenol metabolites (Figs. 9b,c,d). Theselatter gradually accumulate also around resin-bearingcanals and in surrounding tissues, which become increas-ingly enriched in phenols (Fig. 9c,d). Phenol accumula-tion is directly linked to the presence of lead. Samplesfrom heavily polluted stations were randomly subdividedinto two groups: lead was assayed in one series of sam-ples, and phenols were cytochemically identified in theother, all tests being replicated. The constancy of theresults suggests that a direct correlation could be made.

Conclusion

Heavy metal contents in the pine needles analysed hereare due partly to direct assimilation from the soil andpartly to wet and dry deposition of atmospheric particu-late on the aerial parts of pine trees. For some elements,normally emitted into the atmosphere in the gaseousstate, gas-solid conversion on vegetal surfaces may con-stitute and important uptake process. Statistical analysisof data allowed elements in needles to be subdivided intothree groups: (a) elements associated with clay minerals(Al, La, Sm, Sc), (b) elements associated with the calca-rous substrate (Ca and Sr) and (c) elements associatedwith anthropogenic activities (Pb, Br, Sb, Cu, Zn).Comparisons with the chemical composition of the mainlithotypes composing the soil of Palermo confirmed thatthe excess of Pb, Sb and some Br in the needles is due toanthropogenic emissions. The origin of Zn and Curemains uncertain, although wholly crustal origin appearsdoubtful. As lead isotope data indicate that some anthro-pogenic lead becomes attached to the surface of needles,the same process may be hypothesized for the othermetals, especially Sb.Our observations show that in the species of Pinus pineaL. examined here, the accumulation of phenols gives riseto a specific pattern of metabolites providing mechanismsof detoxification and protection, so that the degree ofaccumulation may be proposed as a marker of environ-mental pollution. It does depend on secondary stressphenomena, i.e. on the presence of heavy metals in urbanaerosols. The contribution of other gaseous pollutants(SO2, O3, NOx) cannot be excluded, since they are emittedby the same sources identified for heavy metals. In anycase, the results presented here confirm the presence ofsuch metals in the urban air of Palermo and highlighttheir danger to vegetation. Judging from the obtainedresults, the same danger risk may be transferred tohuman beings. Lastly, this paper represents a furtherexample of how the use of a wide variety of techniques isa modern approach to environmental control, improvingthe reliability of geochemical methods.

Acknowledgements The authors acknowledge M. Martin(University of Geneva) for its technical assistance in Pb isotopedeterminations. This work was funded by CNR-Istituto diGeochimica dei Fluidi and Italian MURST (60%).

References

Abate B, Catalano R, Renda PM (1978) Schema geologicodei Monti di Palermo. Boll Soc Geol It 97 : 807±819

Alaimo MG, Melati MR, Palmeri E, Bruno A (1997) Inqui-namento urbano e biologia riproduttiva delle Pinaceae. ARS58, 6 : 21±23

Alaimo MG, Palmeri E, Bruno A, Melati MR (1998) Pro-posal for the evaluation of stress caused by environmentalpollution with plants markers: Proceedings of 6th Inter-national Congress on Aerobiology. Perugia (Italy). 31August±5 September, p. 111

Fig. 8Cross section of leaf's lower (basal) portion: dense red dropletsof phenols are visible in the mesophyll, into vacuoles (a).Leaf lacunae and red phenols (b) contouring the cell walls.Cross section of leaf's upper (distal) portion reveals redphenols entirely filling vacuoles of epidermis and mesophyllcells (c, d)

Fig. 9Necrosis of leaf tip (a). Increased production of phenolsaround the resine duct (b±d) in the proximal portions

Cases and solutions


Alaimo R, Ferla P (1979) Presenza di paligorskite nellapolvere trasportata dallo ªsciroccoº in Sicilia. Implicazionigeologiche ed ambientali. Ist Min Petr Geoch Quad 4

Allen SE, Grimshaw HM, Parkinson JA, Quarmby C (1974)Chemical analysis of ecological materials. Blackwell ScientificPublications, Oxford

Alloway WH (1968) Agronomic controls over the environ-mental cycling of trace elements. Adv Agron 20 : 235±274

Badalamenti F, Carapezza M, Dongarrà G, Hauser S,Macaluso A, Parello F (1984) Precipitazioni atmosferichein Sicilia. 1 L'area urbana di Palermo. Rend Soc It Min Petr39 : 81±92

Bargagli R, Barghigiani C, Siegel BZ, Siegel SM (1991)Trace metals anomalies in surface soils and vegetation ontwo active island volcanoes: Stromboli and Vulcano (Italy).Sci Total Environ 102 : 209±222

Bargagli R (1993) Plant leaves and lichens as biomonitors ofnatural or anthropogenic emissions of mercury. In: MarkertB (ed.) Plant as biomonitors. Indicators for heavy Metals inthe Terrestrial Environment. Weinheim : VCH pp 461±484.

Berg T, Royset O, Steinnes E, Vadset M (1995) Atmospherictrace element deposition: principal component analysis ofICP-MS data from moss samples. Environ Pollut 88 : 65±77

Busotti F, Gravano E, Grossoni P, Tani C (1998) Occor-rence of tannins in leaves of beech trees (Fagus sylvatica)along an ecological gradient, detect by histochemical andultrastructural analyses. New Phytol 138 : 469±479

Doe BR, Stacey JS (1974) The application of lead isotopes tothe problem of ore genesis and ore prospect evaluation: areview. Econ Geol 69 : 757±776

Dongarrà G, Varrica D (1998) The presence of heavy metalsin air particulate at Vulcano Island (Italy). Sci Total Environ212 : 1±9

Dmuchowski W, Bytnerowicz A (1995) Monitoring environ-mental pollution in Poland by chemical analysis of scots pine(Pinus sylvestris L.) needles. Environ Pollut 87 : 87±104

Gahan PB (1984) Plant histochemistry and cytochemistry.Accademic Press, London

Ferrari C, Manes F, Biondi E (1994) Alterazioni ambientalied effetti sulle piante. Edagricole Bologna

Kramers JD, Tolstikhin IN (1997) Two terrestrial lead iso-tope paradoxes, forward transport modelling, core formationand the history of the continental crust. Chem Geol139 : 75±110

Kurczynska EU, Dmuchowski W, Wloch W, BytnerowiczA (1997) The influence of air pollutants on needles and stemsof scots pine (Pinus sylvestris L.) trees. Environ Pollut98 : 325±334

Lorenzini G (1993) Le piante e l'inquinamento dell'aria.Edagricole Bologna

Melati MR, Alaimo MG (1997) Phytotoxic effects in plants ofagricultural interest. Euro J Histochem 41 : suppl 1 : 45

Melati MR, Alaimo MG, Palmeri E (1998) Accumulo dimetalli pesanti in piante superiori. Atti 93� Congresso dellaSocietà Botanica Italiana, Arcavacata di Rende, 1±3 october

Monna F, Lancelot J, Croudace I, Cundy AB, Lewis T(1997) Pb isotopic signature of urban air in France and inUK: implications on Pb pollution sources. Environ Sci Tech-nol 31 : 2277±2286

Monna F, Loizeau J-L, Thomas BA, GuØguen C, FavargerP-Y (1998) Pb and Sr isotope measurements by inductivelycoupled plasma-mass spectrometer: efficient time manage-ment for precise improvement. Spectrochim Acta B59 : 1317±1333

Monna F, Aiuppa A, Varrica D, Dongarrµ G (1999) Pb iso-tope composition in lichens and aerosols from eastern Sicily:insights into the regional impact of volcanoes on the environ-ment. Environ Sci Technol 33 : 2517±2523

Nimis PL, Castello M, Perotti M (1990) Lichens as bioindi-cators of heavy metal pollution: a case study at La Spezia (N.Italy). Lichenologist 22 : 265±284

Rambaek JP, Steinnes E (1980) Atmospheric deposition ofheavy metals studied by analysis of moss samples using neu-tron activation analysis and atomic absorption spectrometry.Nuclear Methods in Environmental and Energy Research.Conf-800433, Columbia, MO, pp 175±180

Strack D, Heilemann J, Momken M, Wray V (1998) Cellwall-conjugated phenolic from coniferae leaves. Phytochem-istry 27 : 3517±3521

Watmough S (1997) An evaluation of the use of dendrochemi-cal analyses in environmental monitoring. Environ Rev5 : 181±201

Zobel A, Nighswander JE (1991) Accumulation of phenoliccompounds in the necrotic areas of Austrian and red pineneedles after spraying with sulphuric acid: a possible biondi-cator of air pollution. New Phytol 117 : 565±574

Recognition of environmental trace metal contamination using pine needles as bioindicators. The...

Documents

Transcript of Recognition of environmental trace metal contamination using pine needles as bioindicators. The...