Cadmium,zinc and total mercury levels in the tissues of several fish species from La Plata river estuary,Argentina

A survey of the concentrations of heavy metals — cadmium, zinc and total mercury — in the tissues of fifteen fish species from Samborombón Bay, La Plata river estuary, in Argentina, has been carried out. Liver appeared to be the main organ accumulating cadmium and zinc, while both liver and muscle showed a similar ability for accumulating mercury. The bioaccumulation process was verified for the three metals analyzed, even though low concentrations have been determined. The biomagnification process of the metals studied was not verified in this environment. The highest metal concentrations were recorded in Mugil liza, and particulate matter and sediments — which are closely related to its trophic and ecological habits — seemed to be the main source of metals for this species. Both Micropogonias furnieri and Mugil liza were recognized as possible indicator species for future monitoring programmes for heavy metals in Samborombón Bay. Considering the present results, this area of La Plata river estuary is characterized as a non-polluted environment.Scientific Researcher from the National Council for Scientific and Technological Researches (CONICET), of Argentina     

Environmental variation between habitats and uptake of heavy metals by Urtica dioica

The observation from previous surveys, that Urtica dioica plants that had grown in metal contaminated soil in the floodplains of the former Rhine estuary in different habitats, but at comparable total soil metal concentrations, showed significant differences in tissue metal concentrations, led to the hypothesis that variation in other environmental characteristics than soil composition and chemical speciation of metals between habitats is also important in determining uptake and translocation of metals in plants. A field survey indicated that differences in root Cd, Cu and Zn concentrations might partly be explained by variation in speciation of metals in different habitats. However, shoot concentrations showed a different pattern that did not relate to variation in soil metal concentrations. In a habitat experiment Urtica dioica plants were grown in artificially contaminated soil in pots that were placed in the four habitats (grassland, pure reed, mixed reed, osier bed) that were also included in the field survey. After seven weeks the plants showed significant differences in Cu and Zn concentrations in roots and aboveground plant parts and in distribution of the metals in the plants between habitats. It was concluded that variation between habitats in environmental characteristics other than soil composition can explain as much variation in plants as can variation in soil metal concentrations and/or speciation. The implications for assessment of soil metal contamination and uptake by plants are discussed.     

Enteromorpha flexuosa (Wulfen) J. Agardh (Chlorophyta: Ulvales)--evaluation as an indicator of heavy metal contamination in a tropical estuary

The use of bioindicators for contaminant monitoring ispopular in all sectors of the environment but quite oftenbioindicators are utilised without rigorous evaluation oftheir viability as an indicator. We report field andlaboratory investigations into the value of a commonlyfound macroalga, Enteromorpha flexuosa (Wulfen) J.Agardh (Chlorophyta: Ulvales) as an indicator of copper,zinc and lead contamination in a tropical estuary inFiji. In the laboratory, metal content of E.flexuosa after 60 days of growth in seawater containingincreasing concentrations of the metals showed almostperfect correlation with metal concentrations in waterfor all three metals, and concentration factors obtainedwere generally higher than values reported for otherspecies of Enteromorpha. Performance in the fieldwas evaluated by a one-year monitoring of metals in E. flexuosa, water and sediments from a contaminatedestuary. Metal concentrations in water were always belowdetection limits and field concentration factors couldnot be determined but the concentration of lead in E. flexuosa showed a high correlation with the leadcontent of sediments. Lack of such correlation forcopper and zinc in the field suggests that otherenvironmental factors besides metal load in the physicalenvironment could be controlling the bioaccumulation ofthese two metals. Whilst demonstrating E. flexuosato be a viable bioindicator for lead, these results alsohighlight the need for proper assessment before anorganism is considered for environmental monitoring.     

Cd,Cr, Cu,Pb, and Zn concentrations in <Emphasis Type="Italic">Ulva lactuca,Codium fragile,Jania rubens,</Emphasis> and <Emphasis Type="Italic">Dictyota dichotoma</Emphasis> from Rabta Bay,Jijel (Algeria)

Concentrations of Cd, Cr, Cu, Pb, and Zn were determined in algae samples collected from the Rabta Bay in the Mediterranean Sea, Algeria. The levels of heavy metals in the macroalgae, Ulva lactuca, Codium fragile (green algae), Jania rubens (red algae), and Dictyota dichotoma (brown algae) recorded high concentrations except for Cd. Moreover, Zn was the most predominant metal in the seaweeds. The obtained HM contents indicate that different species demonstrate various degree of metal accumulation and the obtained higher values in site 1 of the studied zone can be attributed to the discharge influence of two rivers (Mouttas and Larayeche Rivers), entering the Mediterranean Sea and local pollutant emissions. The abundance of heavy metal concentrations in the macroalgae samples was found in the order below: Zn > Cu > Pb > Cr > Cd from the studied zone. The highest amounts of heavy metals in algae samples were Cd, Cu, and Pb in brown algae, and Cr and Zn in green and brown algae from the studied zone (Rabta Bay).     

Benthic foraminiferal assemblages as pollution proxies in the northern coast of Gabes Gulf,Tunisia

A study of chemical and sedimentological parameters integrated with benthic foraminifera investigation was conducted along the northern coast of Gabes Gulf. Thirty-two samples were studied and a total of 68 benthic foraminiferal species were identified. Heavy metals enrichment factors and total hydrocarbon concentrations showed both metal and petrogenic pollution related mainly to phosphogypsum, sewage, and fishing activities. Statistical analysis (bivariate correlation and hierarchical cluster analysis) show a possible control of these pollutants on density, diversity, as well as the taxonomic composition of the benthic foraminiferal assemblages. The extent to which the population was found less dense and less diversified corresponded to the degree to which the sediment was contaminated. In these contaminated sites, an increase in relative abundance of opportunistic species such Ammonia tepida and Haynesina germanica was found. Far from pollution, foraminiferal assemblages are dominated by species characteristic of Mediterranean shallow water (Ammonia beccarii, Ammonia parkinsoniana, Elphidium crispum, Elphidium williamsoni, Elphidium advenum, Peneroplis planatus, Peneroplis pertesus).     

Near-shore distribution of heavy metals in the Albanian part of Lake Ohrid

The heavy metal contamination in Lake Ohrid, a lake shared between Albania and Macedonia, was studied. Lake Ohrid is believed to be one of the oldest lakes in the world, with a large variety of endemic species. Different anthropogenic pressures, especially heavy metal influxes from mining activities, might have influenced the fragile equilibrium of the lake ecosystem. Heavy metal concentrations in water, sediment, emergent vegetation, and fish were investigated at selected sites of the lake and a study of the heavy metals in five tributaries was conducted. The lake surface water was found to have low levels of heavy metals, but sediments contained very high levels mostly near river mouths and mineral dump areas with concentrations reaching 1,501 mg/kg for Ni, 576 mg/kg for Cr, 116.8 mg/kg for Co and 64.8 g/kg for Fe. Sequential extraction of metals demonstrates that heavy metals in the sediment are mainly present in the residual fraction varying from 75% to 95% in different sites. High heavy metal levels (400 mg/kg Ni, 89 mg/kg Cr, and 39 mg/kg Co) were found in plants (stem of Phragmites australis), but heavy metals could not be detected in fish tissue (gill, muscle, and liver of Salmo letnica and Salmothymus ohridanus).     

Heavy metals concentrations in zooplankton and suspended particulate matter in a southwestern Atlantic temperate estuary (Argentina)

The present work includes part of the first studies of metals concentrations in the zooplankton from a heavily industrialized estuary of Argentina, the Bahía Blanca estuary. Cd, Cu, and Pb concentrations in the zooplankton (macro- and mesozooplankton) and the suspended particulate matter were measured at stations with different degree of pollution. Physicochemical variables and zooplankton composition and abundance were also analyzed. Thus, the aim of the present work was to analyze the spatial and temporal distribution of heavy metals in these two different fractions, and the possible relation among them due to their importance in the biogeochemical cycles of marine environments. Samplings were carried out during a year, from March 2005 to April 2006, every 2 months, at stations located near chemical and petrochemical industries, stations far from these points and one station in an intermediate location. In the mesozooplankton, the mean concentrations of Cd, Cu, and Pb were 3.63?±?1.46, 34.46?±?5.40, and 11.54?±?3.04 μg?g^?1 dry weight (d.w.) respectively, while in the macrozooplankton, 3.20?±?2.28, 21.86?±?4.79, and 8.36?±?1.85 μg?g^?1 d.w. On the other hand, particulate Cd, Cu, and Pb presented a mean concentration of 3.33?±?1.22, 12.75?±?2.67, and 12.53?±?3.20 μg?g^?1 d.w., respectively. Metals’ levels in both the SPM and zooplankton fluctuated throughout the study time and were relatively high in the particulate phase especially for Cu and Pb. Moreover, zooplankton accumulated important concentrations of the three metals. The sources of them are probably the discharges of the industries and domestic sewages located near the estuary.     

Speciation of selected heavy metals geochemistry in surface sediments from Tirumalairajan river estuary, east coast of India

Surface sediment samples from the Tirumalairajan river estuary were studied for grain size pattern, organic matter, and heavy metals (Fe, Mn, Zn, and Pb) using the sequential and bulk metal extraction methods to evaluate metal behavior. Ten surface sediment samples were collected during the monsoon and summer seasons of the year 2009. The observed orders of concentrations of heavy metals in the sediments were as follows: Fe?>?Mn?>?Zn?>?Pb. The results obtained from sequential extraction showed that, among the metals studied, a larger portion of the metals were associated with the residual phase, although they are available in other fractions. The low concentration of metals available in bioavailable phases indicated that the sediments of Tirumalairajan river estuary were relatively unpolluted. Correlation analysis was also carried out to understand the associations of metals in different phases with sand, silt, clay, and organic matter. To understand the risk of heavy metals to sediment-dwelling organisms, the data were compared with risk assessment code and sediment quality values using the screening quick reference table. The main source of metals to the estuary is from the irrigation field and its associated activities in the study area.     

The mismatch of bioaccumulated trace metals (Cu,Pb and Zn) in field and transplanted oysters (<Emphasis Type="Italic">Saccostrea glomerata</Emphasis>) to ambient surficial sediments and suspended particulate matter in a highly urbanised estuary (Sydney estuary,Australia)

A significant correlation between sedimentary metals, particularly the ‘bio-available’ fraction, and bioaccumulated metal concentrations in the native Sydney rock oyster (Saccostrea glomerata) tissues has been successfully demonstrated previously for Cu and Zn in a number of estuaries in New South Wales, Australia. However, this relationship has been difficult to establish in a highly modified estuary (Sydney estuary, Australia) where metal contamination is of greatest concern and where a significant relationship would be most useful for environmental monitoring. The use of the Sydney rock oyster as a biomonitoring tool for metal contamination was assessed in the present study by investigating relationships between metals attached to sediments and suspended particulate matter (SPM) to bioaccumulated concentrations in oyster tissues. Surficial sediments (both total and fine-fraction), SPM and wild oysters were collected over 3 years from three embayments (Chowder Bay, Mosman Bay and Iron Cove) with each embayment representing a different physiographic region of Sydney estuary. In addition, a transplant experiment of farmed oysters was conducted in the same embayments for 3 months. No relationship was observed between sediments or SPM metals (Cu, Pb and Zn) to tissue of wild oysters; however, significant relationship was observed against transplanted oysters. The mismatch between wild and farmed, transplanted oysters is perplexing and indicates that wild oysters are unsuitable to be used as a biomonitoring tool due to the involvement of unknown complex factors while transplanted oysters hold strong potential.     

Monitoring trace metal contamination in salt marshes of the Westerschelde estuary

A survey is given of the possibilities and restrictions of (bio)monitoring trace metals in the salt marsh as exemplified for the Scheldt estuary. The objectives for monitoring in the salt marsh are enumerated as well as the requirements they should meet. Previous studies on monitoring trace metals in the salt marsh are reviewed.Problems in monitoring trace metals in the soil subsystem are due to variations in the input of these metals, the type of esturine circulation and the distribution of physical and chemical conditions in the salt-marsh deposits. The degree of metal enrichment and the spectrum of chemical speciation of the metals by means of a sequential extraction procedure is shortly discussed.Problems in monitoring trace metals in salt-marsh plants are discussed with respect to the bioavailability of these metals from soil and inundation water as sources of contamination, the allocation and seasonal variation in metal accumulations, and the role of adhesive particulate matter carried on the shoots by the floods. Aster tripolium seems to be a good species for biomonitoring trace metals in the vegetational component of the salt-marsh ecosystem.Communication Nr. 346.     

Reduced Metals Concentrations of Water, Sediment and Hyalella Azteca from Lakes in the Vicinity of the Sudbury Metal Smelters, Ontario, Canada

Hyalella azteca (Crustacea: Amphipoda), water and sediments from 12 circum-neutral lakes between Sudbury and North Bay in Ontario, Canada were sampled in August 1998 and analyzed for 10 metals including Cu, Zn, Cd, Ni, Pb, Co, Mo, V, Ba and Ti. Statistical analyses showed that concentrations of the metals in H. azteca, water and sediment differed significantly (ANOVA, P<0.05) among lakes (except for Zn and Pb in H. azteca and Mo in water). There was a trend of declining metal concentration, especially for Cu, Ni and Co (in water, Hyalella and sediment), with distance from the smelters indicating the reduced impact of atmospheric pollution. Metal concentrations of lakes (water) in the Sudbury area were found to be lower compared to data from the 1970s and 1980s indicating an improvement in water quality. Metal concentrations in field-collected amphipods compared favorably with those measured in the laboratory in animals exposed to deep-water sediments, provided metal concentrations were not extremely low (e.g., Pb) and that water chemistry differences (e.g., pH) were taken into account for some metals (especially Cd). In general bioaccumulation of metals in H. azteca was predicted better from surface water than from sediment total metal.     

Assessment of dissolved heavy metal in the Yangtze River estuary and its adjacent sea, China

The purpose of this paper is to determine the concentrations of dissolved heavy metals namely mercury (Hg), lead (Pb), cadmium (Cd), and copper (Cu) and to investigate the relationships between nutrients (nitrate-nitrogen and phosphate) and dissolved heavy metals. For this purpose, the concentrations of dissolved heavy metals were measured through 51 voyages form 1984 to 2006 in the Yangtze river estuary and its adjacent sea. Results analysis showed that dissolved heavy metals were not the main pollutants in the Yangtze river estuary, and the main source of heavy metal contamination was industrial wastewater from terrestrial pollution during the past 20 years. Heavy metal values showed significant abundance in the south branch of the Yangtze River estuary and Hangzhou Bay. In addition, Pb showed negative correlation with nutrients, while the positive correlations between Hg, Cd, and nutrients were shown. The obtained molar ratios, $\Delta \mbox{Cd}/\Delta \mbox{N} = 1.68 \times 10^{-5}$ and $\Delta \mbox{Cd}/\Delta \mbox{P} = 1.66 \times 10^{-4}$ , are close to those in plankton, showing the biogeochemical behavior and process of dissolved cadmium.     

Heavy and trace metal concentrations in three rockpool shrimp species (Palaemon elegans, Palaemon adspersus and Palaemon serratus) from Tenerife (Canary Islands)

Trace metal concentrations (Fe, Cu, Co, Zn, Ni and V) were investigated in three rockpool shrimp species (Palaemon elegans, Palaemon adspersus and Palaemon serratus) from six littoral sampling sites (polluted and non-polluted) of Tenerife in the Canary Islands (Central Eastern Atlantic), Spain. Sex ratio for all three species has been determined: females predominate over males in all species and significant differences in total length and cephalothorax length was detected between sexes, being females larger than males. By other side, concentrations of trace metals were determined in whole specimens. Higher mean values for every metal were observed in P. adspersus. In males, higher values were observed in P. elegans and P. serratus, whereas in P. adspersus, mean values are higher in females. Finally, mean concentrations of trace metals studied were higher, in general terms, in the two clearly polluted stations: Santa Cruz of Tenerife commercial harbour and its fishery dock dependency.     

Heavy metals and arsenic concentrations in ten fish species from the Šalek lakes (Slovenia): assessment of potential human health risk due to fish consumption

The study, which measured the concentrations of Hg, Pb, Cd, Zn and As in various fish tissues (muscle, gill and liver) of 10 fish species (Abramis brama danubii, Alburnus alburnus alburnus, Barbus meridionalis petenyi, Carassius auratius gibelio, Cyprinus carpio, Lepomis gibossus, Leuciscius cephalus cephalus, Perca fluviatilis fluviatilis, Rutilus rutilus, Scardinus erythrophtlalmus erythrophtlalmus) collected in the Šalek lakes, is the first survey regarding metal concentrations in fish species with samples originating from Slovene lakes, while only a limited number of such studies have been carried out in southeastern Europe. Since these lakes are situated in the close vicinity of the largest Slovene thermal power plant, the study provides an insight into the potential impact of increased levels of metals in the environment as well as an estimate of the contamination of fish tissues with metals. Furthermore, it was possible to compare the results obtained with those from other studies regarding metal levels in freshwater fish species. The mean metal concentrations of different tissues irrespective of species varied in the following ranges: Zn 4.31–199 mg/kg ww, Pb 0.01–0.48 mg/kg ww, As 0.02–0.44 mg/kg ww, Hg <0.01–0.31 mg/kg ww, Cd < 0.01–0.19 mg/kg ww. In general, higher contents of Hg were found in muscles and livers than in gills and higher contents of As in gills and livers than in muscles, respectively. The accumulation of Pb and Zn was most pronounced in gills. The result obtained regarding metal concentrations in fish revealed that the ecosystems of the Šalek lakes are not polluted with Hg and Pb, slightly loaded with As and Cd and moderately polluted with Zn. In addition, the potential human health risk due to fish consumption was assessed. This showed that the estimated weekly intakes for all metals were far below provisional permissible tolerable weekly intakes determined by WHO/FAO. The consumption of fish from the Šalek lakes, therefore, does not pose a risk to human health.     

Presence, distribution, and origins of polycyclic aromatic hydrocarbons (PAHs) in sediments from Bahía Blanca estuary, Argentina

This paper is the first comprehensive survey of polycyclic aromatic hydrocarbons (PAHs) in coastal sediments in Bahia Blanca, Argentina, and provides useful information on their levels of concentration, composition, and sources of these pollutants. The total concentrations of PAHs ranged from 15 to 10,260 ng g^???1. The highest contents (mean 3,315 ng g^???1) of total PAHs in marine sediments were found in the inner channels of the estuary, while the lower ones (204 ng g^???1) belong to samples collected far away from contamination sources. The global average recorded in this study (1,500 ng g^???1) indicates that the studied area lies within the referenced category of industrialized coastal zones under chronic pollution. The diagenetic PAH contribution was found to be negligible at all sampled locations; however, the calculation of molecular ratios determined an overimposition of pyrolitic PAHs over the petrogenic input. Further, the use of principal components analysis (PCA) clearly separated ring group compounds and enabled the determination of pyrolitic/combustion PAHs dominancy.     

A case study of trace metals in suspended particulate matter and biota before wastewater treatment plant from the Izmir Bay,Turkey

The concentrations of trace metals (Cu, Zn, Mn, Ni, and Fe) from suspended particulate matter (SPM) and biota in Izmir Bay (Eastern Aegean Sea) were studied in order to evaluate the environmental impact of the anthropogenic metals before building of Wastewater Treatment Plant. SPM samples were collected in wet and dry periods from Izmir Bay. Metal concentrations in SPM (Cu, 0.36–2.19; Mn, 0.07–11.3; Ni, 0.43–7.81; Zn, 7.33–269; Fe, 1.00–266 μgdm^− 3) were comparable to those reported for other moderately polluted bays. Maximum metal concentrations in SPM were observed during summer season. SPM metal concentrations displayed a clear spatial trend with values increasing with proximity to urban centers. Cu and Zn concentrations in SPM were especially high in the inner bay. SPM were found to be contaminated by Zn. The vertical profile of Mn, Zn, and Ni concentrations in SPM had a maximal value at the upper layer and decreased to minimal value at the bottom layer of the inner bay in summer, in contrast to the observed pattern of Fe and Cu. Maximum Cu concentrations were obtained in Penaeus kerathurus. Also, maximum Zn and Fe concentrations were found in Mytilus galloprovincialis. Relatively high Cu levels were found in Sardina pilcardus and Mullus barbatus than other fish species. Besides, Cu levels were lower in Diplodus annularis and Merluccius merluccius. Finally, metal levels in biota tissues were lower than the limits of European Dietary Standards and Guidelines.     

Bioreclamation of coalmine overburden dumps—with special empasis on micronutrients and heavy metals accumulation in tree species

Major environmental impacts of opencast mining are degradation of landscape and aesthetics of the area by creating huge overburden dumps and deep voids at the mining sites. These overburden dumps are characterised by high rock fragment contents, low moisture retention capacity, higher bulk density, low nutrients, lower pH and elevated metal concentrations. Overburden dumps are reclaimed by tree species for stabilising as well as pollution control and overall improvement of the visual aesthetics. A field study was carried out in the old reclaimed coal mine overburden dumps at KD Heslong project, Central Coalfields, India to study the physico-chemical changes in the reclaimed overburden dumps and determines the magnitude of trace elements accumulation in the planted tree species. Total, bioavailable and acid extractable trace metals concentration in minesoils of overburden dump and topsoil in the mining areas was compared with undisturbed soil. The study showed that tree plantation improves the moisture contents, bulk density, pH and overall nutrient contents of minesoils. The study revealed that lower pH in the minesoils increases the bioavailabity of metals but concentration were found within toxic limits. However, ratio between total and bioavailable metals was found lower in overburden dumps than topsoil due to low pH and lack of organic matter. Out of six tree species studied, Bambusa shows highest accumulation of Fe and Cr. Bioaccumulation coefficient for Cr and Zn was found 74 times in Bambusa and 83 times in Dalbergia sissoo. The results of the study underscore the need for close monitoring of trace elements in reclaimed overburden dumps. Tree species like Dalbergia sissoo, Eucalyptus, Cassia seamea, Acaccia mangium and Peltaphorum were found to be the best species for bioreclamation of overburden dumps.     

An Effective Means of Biofiltration of Heavy Metal Contaminated Water Bodies Using Aquatic Weed Eichhornia crassipes

Various aquatic plant species are known to accumulate heavy metals through the process of bioaccumulation. World’s most troublesome aquatic weed water hyacinth (Eichhornia crassipes) has been studied for its tendency to bio-accumulate and bio-magnify the heavy metal contaminants present in water bodies. The chemical investigation of plant parts has shown that it accumulates heavy metals like lead (Pb), chromium (Cr), zinc (Zn), manganese (Mn) and copper (Cu) to a large extent. Of all the heavy metals studied Pb, Zn and Mn tend to show greater affinity towards bioaccumulation. The higher concentration of metal in the aquatic weed signifies the biomagnification that lead to filtration of metallic ions from polluted water. The concept that E. crassipes can be used as a natural aquatic treatment system in the uptake of heavy metals is explored.     

Probabilistic risk assessment and risk mapping of metals in tropical estuarine sediments using the 1 quarisk model

Total sediment concentrations of Cd, Cu, Pb, Zn, As, and Hg obtained from the Ankobra, Sakumo II, and Volta estuaries in Ghana were used to generate contaminant probability density distributions and species sensitivity distributions in AQUARISK. Results of the tier 1 assessment showed Cu, Cd, Zn, and Pb were not of concern in the Ankobra as their measured values and the 99th percentile of the fitted distributions were lower than the SQG low-trigger values. Mercury (Hg) and As were however, identified to be of concern in this estuary. In the Sakumo II estuary, Cu, Cd, Pb, and Hg have been identified to be of concern because their concentrations are higher than the SQG low-trigger values. Hg has been identified as the only metal of concern in the Volta estuary. The total proportion of species likely to be affected by the combined concentration of Cd, Cu, and Zn measured from Ankobra, Sakumo II, and Volta were 14%, 16%, and 12%, respectively, according to the Bur III distributional analysis of the ecotoxicology data. The measured median sediment concentrations of As and Hg in the Ankobra estuary greatly exceeded the median sediment concentration targets to achieve a 5% or less exceedence of the SQG low value. Similarly, in the Sakumo II estuary, the measured median sediment concentrations of Cu, Pb, and Hg greatly exceeded the median sediment concentration targets to achieve a 5% or less exceedence of the SQG low. For the Volta estuary however, other metals except Hg fall below the target values.     

Contribution to biomonitoring of some trace metals by deciduous tree leaves in urban areas

Leaves of the deciduous tree species, horse chestnut (Aesculus hippocastanum L.) and Turkish hazel (Corylus colurna L.) were used as accumulative biomonitors of trace metal pollution in the urban area of Belgrade. Using differential pulse anodic stripping voltametry, trace metal concentrations (Pb, Cu, Zn, Cd) were determined at the single leaf level (ten leaves per species, per month), during two successive years with markedly different atmospheric level of trace metals. Increased trace metal concentrations in the leaves of A. hippocastanum reflected elevated atmospheric trace metal pollution, whereas C. colurna L. did not respond accordingly. The contents of Pb and Zn in soil over the same period also followed this trend. Anatomical analyses, in young as well as in old leaves of both species, indicated typical foliar injuries of plants exposed to stressful air conditions. Water relations that correspond to leaf age may have contributed to the considerable trace metal accumulation in leaves.