Interactions between metals accumulated in the narrow-clawed crayfish Astacus leptodactylus (Eschscholtz, 1823) in Dikilitaş Lake,Turkey

The accumulations of Al, Cd, Cr, Cu, Fe, Ni, Pb and Zn in the exoskeleton, gills, hepatopancreas and abdominal muscles of crayfish Astacus leptodactylus (Eschscholtz, 1823) were determined. The strongest correlation observed was between Cr and Ni in the gills (r?=?0.904); moderate to strong correlations between Al, Cr, Fe, Ni and Cu were also observed in gill tissue. Disregarding the gills, the strongest correlation was found between Cu and Zn in the hepatopancreas (r?=?0.808); the correlation between these two metals might have been a result of metallothionein activity. The accumulation of Pb was found to correlate with that of Cd in the exoskeleton, Cd and Zn in the gills, Zn and Cu in the hepatopancreas and Cu in the abdominal muscle. None of these correlations were present in lakewater and sediment samples, suggesting that the crayfish metabolism may be responsible for the co-accumulation of metal–metal pairs. As all correlations in non-gill tissues are observed between divalent metals, a shared transporter such as divalent metal transporter 1 might be involved in the accumulation of these metals.     

Remediation rates and translocation of heavy metals from contaminated soil through Parthenium hysterophorus

The potential translocation of heavy metals by Parthenium hysterophorus over 30 and 90 days and its effect on biomass, chlorophyll content and photosynthetic activity were studied on 0, 10, 25, 50 and 100% fly-ash-amended soil (FAS). The results showed a decrease in chlorophyll content and photosynthetic area on exposure to 50–100% FAS. Heavy metal reduction was in the order Pb>Cd>Zn>Fe>according to accumulation trends. The plant exhibited good biomass growth on exposure to 25–50% FAS, but this decreased at>100% FAS. Heavy metal concentrations in P. hysterophorus after 90 days of the experiment were in the order Fe>Zn>Cu>Pb>Cd>Ni. Parthenium hysterophorus was suitable for translocating Fe, Zn and Cu based on translocation factors (TF=1.5, 1.3 and 1.05), but was more efficient for Pb, Ni and Cd (TF=8.5, 4.3 and 3.3). Plant uptake of Pb, Ni and Cd was high, whereas translocation of Fe, Zn and Cu was poor. These results indicated that P. hysterophorus can efficiently reduce heavy metal pollution in soil.     

Trace metals in fish of economic interest from the west of Alexandria,Egypt

The concentration of some heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, and Zn) in the muscle, liver, and gills in eight fish species, Caranx crysos, Euthynnus alleferatus, Scomberomorus commerson, Sphyraena viridensis, Sargus sargus, Siganus rivulatus, Mugil species, and Sardinella aurita were collected seasonally from the Mediterranean Sea in the region of Alexandria. The highest concentrations of Cd, Cu, Fe, and Zn were measured in liver tissue, while gill tissue yielded the highest concentrations of Mn, Ni, and Pb. Muscle is the organ of poor accumulation factor for all metals under investigation. Concentration of cadmium in muscle in Mugil species exceeds the permissible limit in summer, while Siganus rivulatus exceeds it in the summer and autumn seasons. On the other hand, copper, nickel, lead, and zinc are still much lower than the permissible levels. The metal pollution index (MPI) for metals was studied, revealing that Siganus rivulatus, Mugil species and Sardinella aurita had the highest MPI. Provisional tolerable daily intake (PTDI) indicates that the concentration levels of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in the muscle of all fish species under investigation are much lower than recommended PTDI values, and accordingly there is no risk for the human consumption of these fish species.     

Assessment of heavy metals in water,sediment, Anabas testudineus and Eichhornia crassipes in a former mining pond in Perak,Malaysia

The concentrations of Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn and Zn were analysed in water, sediment, muscle of climbing perch fish (Anabas testudineus), and tissue of water hyacinth plants (Eichhornia crassipes) collected from a former tin-mining pond in Perak, Malaysia. The monitoring was performed during the minimum and maximum rainfall periods. The concentrations of As, Cr, Fe, Ni, Pb and Zn in water exceeded the permissible limits set by the Interim National Water Quality Standards for Malaysia (INWQS). The risk index (RI) values determined for As, Cd, Cr, Cu, Hg, Pb and Zn in sediment presented a low degree of ecological risk. The order of the top three heavy metals measured in fish muscle was Zn?>?Fe?>?Al. The estimated daily intake (EDI) of As and Cr exceeded the allowable limits in both rainfall periods. The bioconcentration factor (BCF) and translocation factor (TF) values of Zn in water hyacinth were 24.865 and 3.214, respectively. The concentrations of Cu and Zn in the plant tissue were significantly correlated (p?<?.05) with the concentrations of heavy metals in water. Overall, climbing perch and water hyacinth are excellent bioindicators of environmental impacts on water bodies.     

Accumulation and translocation of heavy metals in soil and plants from fly ash contaminated area

The present investigation deals with the accumulation of heavy metals in fields contaminated with fly ash from a thermal power plant and subsequent uptake in different parts of naturally grown plants. Results revealed that in the contaminated site, the mean level of all the metals (Cd, Zn, Cr, Pb, Cu, Ni, Mn and Fe) in soil and different parts (root and shoots) of plant species were found to be significantly (p<0.01) higher than the uncontaminated site. The enrichment factor (EF) of these metals in contaminated soil was found to be in the sequence of Cd (2.33) > Fe (1.88) > Ni (1.58) > Pb (1.42) > Zn (1.31) > Mn (1.27) > Cr (1.11) > Cu (1.10). Whereas, enrichment factor of metals in root and shoot parts, were found to be in the order of Cd (7.56) > Fe (4.75) > Zn (2.79) > Ni (2.22) > Cu (1.69) > Mn (1.53) > Pb (1.31) > Cr (1.02) and Cd (6.06) approximately equal Fe (6.06) > Zn (2.65) > Ni (2.57) > Mn (2.19) > Cu (1.58) > Pb (1.37) > Cr (1.01) respectively. In contaminated site, translocation factor (TF) of metals from root to shoot was found to be in the order of Mn (1.38) > Fe (1.27) > Pb (1.03) > Ni (0.94) > Zn (0.85) > Cd (0.82) > Cr (0.73) and that of the metals Cd with Cr, Cu, Mn, Fe; Cr with Pb, Mn, Fe and Pb with Fe were found to be significantly correlated. The present findings provide us a clue for the selection of plant species, which show natural resistance against toxic metals and are efficient metal accumulators.     

Effects of Cadmium on Nutrient Uptake and Translocation by Indian Mustard

Plants that hyperaccumulate metals are ideal subjects for studying the mechanisms of metal and mineral nutrient uptake in the plant kingdom. Indian Mustard (Brassica juncea) has been shown to accumulate moderate levels of Cd, Pb, Cr, Ni, Zn, and Cu. In this experiment, 10 levels of Cd concentration treatments were imposed by adding 10–190 mg Cd kg^–1 to the soils as cadmium nitrate [Cd(NO₃)₂]. The effect of Cd on phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and the micronutrients iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in B. juncea was studied. Plant growth was affected negatively by Cd, root biomass decreased significantly at 170 mg Cd kg^–1 dry weight soils treatment. Cadmium accumulation both in shoots and roots increased with increasing soil Cd treatments. The highest concentration of Cd was up to 300 mg kg^–1 d.w. in the roots and 160 mg kg^–1 d.w. in the shoots. The nutrients mainly affected by Cd were P, K, Ca, Fe, and Zn in the roots, and P, K, Ca, and Cu in the shoots. K and P concentrations in roots increased significantly when Cd was added at 170 mg kg^–1, and this was almost the same level at which root growth was inhibited. Zn concentrations in roots decreased significantly when added Cd concentration was increased from 50 to 110 mg kg^–1, then remained constant with Cd treatments from 110 to 190 mg kg^–1. However, Zn concentrations in the shoots seemed less affected by Cd. It is possible that Zn uptake was affected by the Cd but not the translocation of Zn within the plant. Ca and Mg accumulation in roots and shoots showed similar trends. This result indicates that Ca and Mg uptake is a non-specific process.     

Metal accumulation in sediment,water, and freshwater fish in a Dam Lake

Metal concentrations were determined in water, sediment, and freshwater fish samples (Squalus cephalus, Barbus esocinus, and Barbus xanthopterus) collected from Karakaya Dam Lake, Turkey, to estimate the risk of human consumption and pollution. Metal concentrations differed between the species (p??Zn?=?Cu in water and Fe?>?Zn?>?Mn?>?Ni?>?Cu in sediment. In general, the accumulation order of elements in the tissues all of the species sampled were found as Fe?>?Zn?>?Se?>?Mn?>?Cu?>?Ni?>?Cd in muscle, Zn?>?Fe?>?Mn?>?Se?>?Cu?>?Ni?>?Cd in gills, Fe?>?Zn?>?Se?>?Mn?>?Cu?>?Ni?>?Cd in liver and gonad, and Zn?>?Fe?>?Cu?>?Mn?>?Se?>?Ni?>?Cd in kidney. It was concluded that the fish from the dam lake are not heavily burdened with metals, but they should be controlled periodically to avoid excessive intake of trace metals by humans, and to monitoring the pollution of aquatic environment.     

Fraction distribution and migration of heavy metals in mangrove-sediment system under sulphur and phosphorus amendment

In this study, mangrove seedlings (Kandelia obovata (S. L.)) were cultivated in rhizo-boxes, which contain sediments collected from natural mangrove forest and modified with different rates of sulphate and phosphate. The fraction distributions of Zn, Cd, Cu, Ni and Pb in rhizosphere and non-rhizosphere sediments were studied by using a sequential extraction method. Metal concentrations in plant tissues and iron plaque on root surface were also determined to reveal migration variation of heavy metals in the plant-sediment system. The results showed that the activities of K. obovata roots enhance the reducible metals while reducing acid-extractable and oxidisable metals; sulphur amendment benefits the combination of metal ions with S^2– and therefore reduces the bioavailability of metal pollutants; addition of sulphur also improves the content of iron plaque on the root surface, which plays an important role in metal accumulation by K. obovata root tissue; the addition of sulphur markedly reduces the concentration of Cd in roots, but significantly enhanced the concentrations of Cu, Zn, Ni and Pb in roots. The results indicate that sulphur and phosphorus content in mangrove sediment, and the growth of mangrove plant can significantly influence the migration of heavy metals in the mangrove wetland ecosystem.     

Trace metal contents ofTaraxacum officinale (dandelion) as a convenient environmental indicator

Some vascular plants are known to concentrate trace metals and are regarded to be suitable indicators of atmospheric metal deposition. Among plant species used for biogeochemical studies dandelion (Taraxacum officinale.) is convenient for monitoring air/soil pollution. The plant commonly occurs in different ecosystems with relatively parallel stages of ontogenesis over a broad area of geographical regions. Its leaves and roots are easily accessible for sampling. Leaf to root ratios of metal concentrations in dandelion may indicate the source of metals during the growing season. Trace metals in leaves and roots of dandelion from 132 sites in Poland showed higher concentrations in the plants from the SW region compared to those from the NE region of the country. However, the differences were only statistically significant ( = 0.05) for Cd, Ni, and Pb. Geometric means of metal concentrations (mg kg^–1, air dried weight) in dandelion leaves of the SW and NE regions were: Cd 0.85, 0.52; Cr 0.99, 0.81; Cu 11.2, 11.1; Fe 184.4, 100.0; Mn 59.7, 51.4; Ni 2.1, 1.5; Pb 4.4, 3.0; and Zn 49.6, 41.3, respectively. Markedly higher concentrations of Cd, Pb, and Zn were found in the leaves of the dandelion over roots in the SW region. These metals are the most serious aerial pollutants in that part of the country.     

Use of the digestive gland of the oyster Crassostrea rhizophorae (Guilding, 1828) as a bioindicator of Zn,Cd and Cu contamination in estuarine sediments (south-east Brazil)

This study demonstrates the accumulation of Zn, Cd and Cu in the digestive gland of the oyster Crassostrea rhizophorae in response to the contamination of sediments and discusses the potential use of this specific organ in monitoring metal contamination in tropical areas. Sediment and oyster samples were collected from coastal Rio de Janeiro sites with different levels of human impact: Sepetiba Bay, Guanabara Bay and the Paraty coast. Metal concentrations were measured using inductively coupled plasma optical emission spectrometry (ICP OES). Significant statistical differences (p<0.001; p<0.05) were observed for Zn and Cd concentrations in the digestive gland; the highest Zn concentrations were found at Sepetiba, followed by Guanabara and Paraty. The highest digestive gland Cd concentrations were found at Paraty, followed by Sepetiba and Guanabara. These concentrations were proportional to those found in the sediments. There was no significant difference (p>0.05) in Cu among the sampling sites. The highest digestive-gland Cu concentration was also found at Sepetiba, followed by Guanabara. The biosediment accumulation factor indicated a gradient of sediment contamination for Zn and Cd. The digestive gland of C. rhizophorae can be a potential indicator of trace metal contamination in sediments from tropical estuarine environments.     

Accumulation of heavy metals in soil and paddy crop (Oryza sativa), irrigated with water of Ramgarh Lake,Gorakhpur, UP,India

Heavy metals, a highly polluting group of constituents known to exert adverse effects, tend to accumulate in living organisms. The objective of this study was to determine the accumulation and translocation of heavy metals in soil and in paddy crop irrigated with lake water compared to soil and paddy crop irrigated with bore-well water. The quantities of heavy metals (Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg) were determined in different parts of rice plants (Oryza sativa). Results revealed that the mean levels of soil Cd, Cr, Pb, Zn, As, Mn, and Hg in experimental soil and in different parts of rice plant (root, straw, and grain) were higher than the control except for Cu. The content of eight toxic metals was significantly higher in root than in aerial parts of the rice (straw and grains). Rice roots were enriched in Cd, As, Hg, and Pb from the soil, while Cr, Cu, Zn, and Mn were hardly taken by the roots. Bioaccumulation factor for Hg was significantly higher than other heavy metals. Metal transfer factors from soil to rice plants were significant for Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg. The concentrations of metals in lake water were found to be within the permissible limit of Indian standard prescribed by Central Pollution Control Board (2000), except for Hg and As, which were higher than the limit of Indian standard. However, the concentrations of heavy metals in soil and rice grains were still below the maximal levels, as stipulated by Indian Prevention of Food Adulteration Act (PFA, 1954) and World Health Organization (WHO, 1993) guidelines.     

Heavy Metals Contamination of Topsoil in the Vicinities of Auto-Repair Workshops,Gas Stations and Motor-Parks in a Nigerian City

Concentrations of Pb, Zn, Cd, Cu,Cr, Co and Ni were determined in topsoil obtained from vicinities of auto-repair workshops, gas-stations and motor-parks in Ibadan, Nigeria. The levels were elevated above background concentrations in control sites. Lead and copper were the most significant contaminants, and the degree of contamination was highest in auto-repair workshops. Factors of accumulation for Pb and Cu were: auto-repair workshops: Pb - 95.8, Cu - 117; gas stations: Pb - 46.6, Cu - 33.5; motor-parks: Pb - 31.6, Cu - 16.8. For Zn, Cd, Cr, Co and Ni, the factors of accumulation were much lower and did not vary much among the three study areas. Average values for all locations were: Zn - 5.2, Cd - 4.4, Cr - 3.7, Co - 1.5, Ni - 1.7. Improper disposal of waste lubricants is the likely source of high copper contamination.     

Heavy metal contamination of soil,and bioaccumulation in vegetables irrigated with treated waste water in the tropical city of Varanasi,India

The present study was conducted to determine the heavy metal contamination in soil with accumulation in plants in waste water irrigated areas. Results revealed that waste water contained lower concentrations of Cr, Zn, Cu, and Pb except Cd (0.03) than the permissible limits prescribed by the World Health Organization. The maximum metal concentrations occurred in Brassica oleracea (Zn 63.80, Cu 12.25, Cr 10.65, Pb 3.63, and Cd 0.56 mg Kg^?1).The metal enrichment (EF of Cd 1.9, Cr2.9, Zn 4.8, Cu 6.5, and Pb 15.5) and degree of contamination (CF of Cd 2.9, Cr 2.0, Zn 2.3, Cu 2.7, and Pb 2.2) showed that accumulation of the five toxic metals increased during sewage irrigation as compared with the reference values, other Indian regions and globally. However, based on WHO standards for heavy metal contamination of soil and irrigation water, our data does not ensure safe levels for food.     

Cadmium,copper, and zinc in carrots in Japan

Cadmium (Cd), copper (Cu), and zinc (Zn) in carrots obtained from different regions throughout Japan were assessed in a baseline study on the contents of trace metals in foods. These three metals were measured by flameless atomic absorption spectrophotometry. The geometric mean contents (with one geometric standard deviation indicated in parentheses) of Cd, Cu, and Zn were 0.02 (2.2), 0.7 (2.1), and 2.4 (1.6) mg?kg^?1 wet weight in carrots obtained in Japan. While there was a close relationship among the contents of the three metals in the carrots grown in Cambisols and Gleysols, a significant relationship was recognized only between the contents of Cd and Zn in those grown in Andosols and Fluvic Gleysols. Cd and Zn are classified as 2B metals in the periodic table of elements, and the authors speculate that the similarity of the metal characteristics between Cd and Zn may be responsible for the close relationship in the contents of the two metals, with no relation to the soil type.     

Bioaccumulation of heavy metals in Octopus vulgaris from coastal waters of Alexandria (Eastern Mediterranean)

Heavy metal concentrations (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were determined in various tissues (hepatopancreas, branchial hearts, salivary gland, gills, genital tract, mantle, arms and skin) of Octopus vulgaris collected from three different contaminated sites in front of Alexandria (Egypt) during 2000. All collected tissues displayed high enrichment factors when compared to ambient levels. Heavy metal concentrations in most tissues displayed significant differences among sites, sizes and sex. This study suggests that hepatopancreas, and to a lesser extent branchial hearts, are better indicators of chronic Cu, Fe, Zn and Cd contamination than edible tissues. The enrichment factor (EF) for heavy metals in the hepatopancreas and in edible tissues allowed discriminating our samples into three main groups; (1) EF?>?55 (Cu), (2) EF ranging from 15 to 7.5 (Fe, Cd and Zn) and (3) EF?相似文献   

红枫湖水源地附近粉煤灰堆积场重金属存在形态及静态淋溶规律

酸雨对露天粉煤灰堆积场的淋滤作用导致周围环境产生重金属污染是一种广泛现象.为研究酸雨对贵阳市水源地红枫湖周边一大型粉煤灰堆积场的重金属迁移影响,本文以这一粉煤灰堆积场为研究对象,通过静态淋溶实验探讨了粉煤灰中Cr、Ni、CU、Zn、AS、Cd、Pb等7种重金属元素的含量、存在形态、淋溶时间、堆积时间、粒度对重金属溶出规律的影响.结果表明,粉煤灰中Ni、Cu、Zn、Pb、As和Cd等6种重金属的含量随堆积时间增加而增大,Cr含量变化与上述反之;在淋溶实验中,堆积时间的增加使Cr、Ni、Cu和Zn重金属元素的可溶态减小;在淋溶第28—48天期间,Cr、Ni和Cu元素溶出浓度降低的粒度顺序为细粒度>中粒度和粗粒度、Cd元素溶出浓度降低的粒度顺序为中粒度>粗粒度>细粒度.本研究对红枫湖水源地和周边地下水的重金属防控提供一定的参考依据.     

Ecological and human health risks from metal(loid)s in peri-urban soil in Nanjing,China

In order to investigate the ecological and human health risks of metal(loid)s (Cu, Pb, Zn, Ni, Cd, Mn, Cr, and As) in peri-urban soils, 43 surface soil samples were collected from the peri-urban area around Nanjing, a megacity in China. The average contents were 1.19, 67.8, 37.6, 105, 167, 44.6, 722, and 50.8 mg kg^?1 for Cd, Cr, Ni, Pb, Zn, Cu, Mn, and As, respectively. A significant positive correlation was found between Cu, Pb, Zn, Cd, Mn, and As (p < 0.01), and Cr had a significant positive correlation with Ni (p < 0.01). Geoaccumulation indices indicate the presence of Cd and As contamination in all of the peri-urban soil samples. Potential ecological risk indices show that the metal(loid)s in the soil could result in higher ecological risks. Cd is the main contributor to the risk, followed by As. The levels of Cu, Pb, Zn, Cd, Mn, and As in stomach and intestinal phases show a positive linear correlation with their total contents. Mn, Zn, Ni, Cd, and Pb in stomach phase showed higher bioaccessibility, while in intestinal phase, Cu, Cr, and As had the higher bioaccessibility. The carcinogenic risk in children and adults posed by As, Pb, and Cr via ingestion was deemed acceptable. The non-carcinogenic risks posed by these metal(loid)s via ingestion to children are higher than to adults and mainly result from As.     

Relationship between total concentration and dilute HCl extraction of heavy metals in sediments of harbors and coastal areas in Korea

Total concentrations of Cr, Ni, Cu, Zn, Cd and Pb in surface sediments were determined to investigate the regional trends of heavy metal contamination in 11 coastal areas in Korea. Enrichment factor (EF) of heavy metals was calculated by comparing the level of their regional background. The averages of EF values in study areas were 0.99 for Cr, 1.05 for Ni, 4.23 for Cu, 1.80 for Zn, 3.92 for Cd and 1.54 for Pb, respectively. Dilute HCl extractions were useful to deduce the anthropogenic sources of heavy metals and the 1 M HCl extractable fractions of each metal varied from 0.3 to 37.3% for Cr, 1.9 to 66.3% for Ni, 4.2 to 92.9% for Cu, 7.1 to 99.7% for Zn, 10.9 to 98.9% for Cd and 15.0 to 99.1% for Pb. Comparing 1 M HCl extractable fraction to total concentration, large portions of Cu, Zn, Cd and Pb were present as potentially bioavailable fractions from anthropogenic input and were significantly correlated with their EF values showing r > 0.68.     

Growth and metal accumulation response of <Emphasis Type="Italic">Vigna radiata</Emphasis> L. var PDM 54 (mung bean) grown on fly ash-amended soil: effect on dietary intake

Plants of Vigna radiata L. var. PDM 54 (mung bean) were grown in soil amended with different amounts (10 and 25%) of fly ash (FA). Although total metal content increased with increasing FA amendment, DTPA-extractable metals were higher for 10% FA. Accumulation of metals by the plants increased with increasing FA amendment and was greater in shoots than in roots (except for Mn and Cu) and seeds (except Mn). The total daily intake (TDI) of all the tested metals in seeds was within the recommended dietary allowance (RDA)/provisional tolerable daily intake (PTDI) for adults, except for Cd, which was higher than recommended values. Principal-components analysis (PCA) based on studies of physicochemical properties, DTPA-extractable metals, and metal accumulation in the different parts of V. radiata showed that physicochemical properties such as cation-exchange capacity, organic carbon, and organic matter had significant positive effects on accumulation of Cd, Co, Ni, and Pb by the plant, whereas EC had a significant negative effect. Although addition of fly ash (10%) initially increased the rate of growth, toxic symptoms were observed for 25% FA. Results from analysis of antioxidants (carotenoids, ascorbic acid, non-protein thiol, and free proline) revealed that these increased more in plants grown in 10% FA than in those grown in garden soil. Cysteine and malondialdehyde (MDA) content increased with increasing FA amendment. PCA also showed that all the antioxidants studied behaved similarly except cysteine, for which there was a close relationship with MDA content. Thus, the results obtained during this study revealed that V. radiata L. var. PDM 54 may be grown in 10% FA and/or contaminated agricultural soil.     

Assessment of metal contamination in soil banks of the Rhumel wadi (Northeast Algeria)

Levels of six trace metals were assessed in bank soils of the Rhumel wadi (Northeast Algeria) and their association with soil properties was investigated. Samples were collected at 10 sites. The soils are neutral to moderately alkaline, have high contents of carbonate, and are low in organic carbon and clay. Mean metal concentrations are 1.1 (Cd), 63 (Cr), 20 (Cu), 26 (Ni), 31 (Pb), and 98 (Zn) mg kg^?1. The Cd, Cu, Pb, and Zn contents in soil from sites closest to Constantine City were higher than in uncontaminated soils worldwide, indicating accumulation due to human activities (residential, industrial, and agricultural). Statistical analyses (correlation and principal component analysis) demonstrated that Cd, Pb, and Zn are of anthropogenic origin in the urban areas, whereas Cr and Cu enrichment in some situations is caused by industrial activities, while Ni was geogenic.