杭州市六种常见绿化树种叶片累积空气重金属特征及与环境因子的相关性

该研究选取杭州市2个污染区常见的6种绿化树种叶片作为材料,以清洁区为对照,采用电感耦合等离子体发射光谱法,测定受试树种叶内及对应样点降尘、土壤中Pb、Cd、Cr、Cu、Ni和Zn的含量,分析叶片的吸污能力以及重金属含量与土壤、降尘的相关性。结果表明:(1)污染区树种重金属含量明显高于对照区,绿化树种对环境重金属污染物有一定的吸收能力,重金属含量在不同的树种中具有明显差异;所测树种叶内Zn含量最大,Pb次之,Cd最小,指示能力则以枸骨(Ilex cornuta)对Cd和Pb、圆柏(Juniperus chinensis)对Cu、茶花(Camellia japonica)对Ni、广玉兰(Magnolia grandiflora)对Zn为最强。(2)3个样点树种叶片与对应样点土壤、降尘中重金属元素含量的相关性分析和回归分析表明,叶片重金属含量与土壤重金属含量的相关性较小,而与降尘呈显著正相关。因此,绿化树种叶片作为空气重金属污染的累积器和监测器是科学合理的,且上述4种树种对杭州市空气中6种重金属污染的指示作用具有一定参考价值,可作为监测城市空气质量的特型树种。该研究结果为减少城市空气重金属污染提供了科学依据和理论支持。     

Changes of photosynthetic parameters in cucumber leaves under Cu,Cd, and Pb stress

The effects of Cu, Cd, and Pb toxicity on photosynthesis in cucumber leaves (Cucumis sativus L.) were studied by the measurements of gas exchange characteristics, chlorophyll (Chl) fluorescence parameters, and Chl content. Concentrations of metals in sequence of 20 μM Cu, 20 and 50 μM Cd, and 1 000 μM Pb decreased the plant dry mass to 50–60 % after 10 d of treatment whereas 50 μM of Cu decreased it to 30 %. The content of Cd in leaves of plants treated with 50 μM Cd was three times higher than the contents of Cu and Pb after plant treatment with 50 μM Cu or 1 000 μM Pb. Hence Cd was transported to leaves much better than Cu and Pb. Nevertheless, the net photosynthetic rate and stomatal conductance in leaves treated with 50 μM Cu or Cd were similarly reduced. Thus, Cu was more toxic than Cd and Pb for photosynthesis in cucumber leaves. None of the investigated metals decreased internal CO₂ concentrations. Also the effect of metals on potential efficiency of photosystem 2, PS2 (F_v/F_m) was negligible. The metal dependent reduction of PS2 quantum efficiency (Φ_PS2) after plant adaptation in actinic irradiation was more noticeable. This could imply that reduced demand for ATP and NADPH in a dark phase of photosynthesis caused a down-regulation of PS2 photochemistry. Furthermore, in leaves of metal-treated plants the decrease in water percentage as well as lower contents of Chl and Fe were observed. Thus photosynthesis is not the main limiting factor for cucumber growth under Cu, Cd, or Pb stress.     

Pb and Cd accumulation and phyto-excretion by salt cedar (Tamarix smyrnensis Bunge)

The accumulation and excretion of lead (Pb) and cadmium (Cd) by salt cedar (Tamarix smyrnensis Bunge) were investigated in this study. Tamarix smyrnensis plants were exposed to the mixtures of Pb and Cd and high salinity for 10 wk. Subsequently, Pb and Cd uptake was quantified in the shoots and roots of the plants by ICP-AES. In addition, physiological parameters such as biomass production, shoot length, plant appearance, and chlorophyll content were examined. The roots accumulated the highest amount of Pb. Salinity was found to not have an important effect on Pb translocation to the leaves. Cd was translocated into the aerial part in a higher portion than Pb. Cd content in leaves of T. smyrnensis increased with the increasing salinity. The visible toxicity symptoms, if present, were connected only to the high salinity. The excretion of Pb and Cd by salt glands was observed and quantified. T. smyrnensis excreted a significant amount of metals on the leaf surface. This characteristic of salt cedar plants can be viewed as a novel phytoremediation process for the remediation of sites contaminated with heavy metals that we have termed "phyto-excretion."     

Usage of sewage effluent in irrigation of some woody tree seedlings. Part 3: Swietenia mahagoni (L.) Jacq.

A pot experiment was investigated to study the effect of sewage irrigation treatments (primary and secondary effluents) compared with tap water on the growth and chemical constituents of mahogany seedlings (Swietenia mahagoni (L.) Jacq.) as well as soil chemical properties. The experiment was conducted at a greenhouse in the nursery of Timber Trees Research Department of Sabahia, Horticultural Research Station in Alexandria, Egypt, from June 2003 to December 2004 for three irrigation periods (6, 12 and 18 months). The sewage effluent waters were taken from oxidation ponds located in New Borg EL-Arab city and used directly for irrigation.The primary effluent treatment was superior than other treatments in improving the growth parameters (plant height, stem diameter, leaf area, leaves number, fresh and dry weights of leaves, shoots and roots and shoot/root ratio) and showed the highest concentration and total uptake of N, P, K, Cd, Ni, Pb and Fe in plant parts, followed by secondary effluent then tap water. The data revealed that soil salinity in terms of electrical conductivity of saturated paste (EC), CaCO₃%, organic matter% and soluble anions and cations were influenced significantly by primary or secondary effluent treatment. The data also showed that the use of sewage effluent for irrigation increased N, P, K and DTPA-extractable-heavy metals (Cd, Cu, Ni, Pb, Fe, Mn and Zn). The effects of sewage effluent on growth parameters and elements content in plant parts and treated soil were more pronounced as water treatments were used for long period.The results suggested that the use of sewage effluent in irrigating mahogany trees grown on calcareous sandy loam soil was an important agriculture practice for improving soil properties, increasing fuel and timber production, and is an economic and safe way to dispose wastewaters.     

淮南矿区大气及二球悬铃木叶片中重金属含量及其相关性分析

对淮南市污染区(矿区)和对照区(相对清洁区)空气中TSP、PM10-100、PM5-10、PM2.5-5和PM2.5的日均质量浓度进行了测定,并对TSP中Cd、Cr、Cu、Ni、Pb和Zn的质量浓度和二球悬铃木〔Platanus×acerifolia(Ait.)Willd.〕叶片中Cd、Cr、Cu、Ni、Pb和Zn含量的动态变化进行了分析,同时对二球悬铃木叶片中重金属含量与TSP中重金属质量浓度和各类空气颗粒物日均质量浓度的相关性进行了分析。结果表明:在60 d采样期内,空气颗粒物日均质量浓度和叶片中重金属含量均呈波动的变化趋势,其中污染区空气中TSP和PM2.5的日均质量浓度均显著高于对照区,污染区PM10-100、PM5-10和PM2.5-5日均质量浓度总体上低于对照区;污染区空气TSP中6种重金属元素的质量浓度均高于对照区,污染区二球悬铃木叶片中的Cd、Cr、Cu、Ni和Zn含量均高于对照区但Pb含量低于对照区。相关性分析结果表明:污染区二球悬铃木叶片中重金属含量与空气TSP中重金属质量浓度多数呈正相关,叶片中重金属含量与空气中PM2.5日均质量浓度也均呈正相关,其中叶片中Cd含量与PM2.5日均质量浓度的相关性达显著水平。研究结果表明:在淮南矿区,可将二球悬铃木叶片中的重金属含量作为空气PM2.5污染状况的监测指标。     

Mobility and Translocation of Heavy Metals from Mine Tailings in Three Plant Species after Amendment with Compost and Biosurfactant

An experiment was performed to determine the effects of mine tailings alone mixed with compost or with compost plus crude biosurfactant on the accumulation of heavy metals (Pb, Zn, Cu, Cr, Cd, and Ni) in Acacia retinodes, Nicotiana glauca, and Echinochloa polystachya. The plants were grown in soil, mine tailings, and mine tailings containing compost over a period of seven and five months for shrubs or grass, respectively. The plants Acacia retinodes and Nicotiana glauca grown in mine tailings containing compost showed increases in dry biomass (from 62 to 79%) compared with plants in only tailings. Heavy metals accumulated in the roots and leaves showed high translocation rates of Cr in N. glauca, Cd in A. retinodes, and Ni in E. polystachya. Concentrations of heavy metals in the three plants irrigated with crude biosurfactant were not significantly different from those irrigated with water. Zn and Cd fractions within mine tailings containing compost were bound to carbonate, Pb was bound to residues, and Cu was bound to Fe-oxides. Cd had the highest mobility factor followed in order by Zn, Pb, and Cu. The elevated concentrations of Pb in roots and the low translocation rate for N. glauca and A. retinodes indicate that they are suitable for phytostabilizing Pb and Zn.     

Bioavailability and Concentration of Heavy Metals in the Sediments and Leaves of Grey Mangrove, <Emphasis Type="BoldItalic">Avicennia marina</Emphasis> (Forsk.) Vierh,in Sirik Azini Creek,Iran

The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales), Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation index (I _geo) was used to determine the degree of contamination in the sediments. I _geo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable sediment) for some metals were higher than 1.     

Effects of atmospheric deposition,soil pH and acidification on heavy metal contents in soils and vegetation of semi-natural ecosystems at Rothamsted Experimental Station,UK

The effects of acidification on the soil chemistry and plant availability of the metals Pb, Cd, Zn, Cu, Mn and Ni in new and archived soil and plant samples taken from the >100-year-old experiments on natural woodland regeneration (Geescroft and Broadbalk Wildernesses) and a hay meadow (Park Grass) at Rothamsted Experimental Station are examined. We measured a significant input of metals from atmospheric deposition, enhanced under woodland by 33% (Ni) to 259% (Zn); Pb deposition was greatly influenced by vehicle emissions and the introduction of Pb in petrol. The build up of metals by long-term deposition was influenced by acidification, mobilization and leaching, but leaching, generally, only occurred in soils at pH<4. Mn and Cd were most sensitive to soil acidity with effective mobilization occurring at pH 6.0–5.5 (0.01 M CaCl₂), followed by Zn, Ni and Cu at pH 5.5–5.0. Pb was not mobilized until pH<4.5. Acidification to pH 4 mobilized 60–90% of total soil Cd but this was adsorbed onto ion exchange surfaces and/or complexed with soil organic matter. This buffering effect of ion exchange surfaces and organic matter in soils down to pH 4 was generally reflected by all the metals investigated. For grassland the maximum accumulation of metals in herbage generally corresponded to a soil pH of 4.0. For woodland the concentration of Pb, Mn and Cd in oak saplings (Quercus robur) was 3-, 4- and 6-fold larger at pH 4 than at pH 7. Mature Oak trees contained 10 times more Mn, 4 times more Ni and 3 times more Cd in their leaves at pH 4 than at pH 7. At pH values <4.0 on grassland the metal content in herbage declined. Only for Mn and Zn did this reflect a decline in the plant available soil content attributed to long-term acid weathering and leaching. The chief cause was a long-term decline in plant species richness and the increased dominance of two acid-tolerant, metal-excluder species     

Effects of toxic heavy metals (Cd,Pb) on growth and mineral nutrition of beech (Fagus sylvatica L.)

The beech (Fagus sylvatica L.) is the dominant tree in Middle Europe under many different ecological conditions. But like other tree species, it is suffering in the last ten years increasingly by air pollutants including heavy metals which have been deposited and accumulated for decades in many forest soils. Increasingly mobilized by acidification processes, these metals may have toxic effects on trees.In autecological studies (dose-response-experiments) effects of root-applied Pb and Cd on various growth parameters, on uptake of mineral nutrients and on transpiration of young beech trees were evaluated, and critical concentrations (threshold levels) could be established. Significant leaf area reduction was found with 6 ppm Pb (0.3 ppm Cd) in the leaves (DW), but biomass reduction only with 18 ppm Pb (3.6 ppm Cd). Root elongation rates of seedlings were significantly reduced with 44 ppm plant-available Pb in the soil by about 30%, but only with 24 ppm Pb when combined with 2 ppm Cd, exhibiting synergistic effects. After treatments with 20 ppm Pb and 1 ppm Cd in sand culture, a considerable decrease in the contents of K, Ca, Mg, Fe, Mn, and Zn in roots and leaves of saplings was coincident with high (roots) and moderate (leaves) accumulation of Pb and Cd. A 20% reduction of transpiration rates was measured in ten-year-old beech trees after three months of exposure to a forest soil containing 2.5 ppm plant-available Cd.The data indicate that present-day concentrations mainly of Pb, but not yet of Cd, in acidified European forest soils are sufficiently high to affect germination, growth and mineral nutrition of natural rejuvenation of beech.The data published here are part of a doctoral and of various diploma theses: Mrs. Christiane Bertels, Barbara Buschmann, Martina Hücker, Gritli Noack, Ute Röder, Swantje von Oy and Mr. Rüdiger Ahrend, Peter Rüther and Frank Weisser.     

Changes of photosynthetic parameters in cucumber leaves under Cu, Cd, and Pb stress

The effects of Cu, Cd, and Pb toxicity on photosynthesis in cucumber leaves (Cucumis sativus L.) were studied by the measurements of gas exchange characteristics, chlorophyll (Chl) fluorescence parameters, and Chl content. Concentrations of metals in sequence of 20 M Cu, 20 and 50 M Cd, and 1 000 M Pb decreased the plant dry mass to 50–60 % after 10 d of treatment whereas 50 M of Cu decreased it to 30 %. The content of Cd in leaves of plants treated with 50 M Cd was three times higher than the contents of Cu and Pb after plant treatment with 50 M Cu or 1 000 M Pb. Hence Cd was transported to leaves much better than Cu and Pb. Nevertheless, the net photosynthetic rate and stomatal conductance in leaves treated with 50 M Cu or Cd were similarly reduced. Thus, Cu was more toxic than Cd and Pb for photosynthesis in cucumber leaves. None of the investigated metals decreased internal CO₂ concentrations. Also the effect of metals on potential efficiency of photosystem 2, PS2 (F_v/F_m) was negligible. The metal dependent reduction of PS2 quantum efficiency (_PS2) after plant adaptation in actinic irradiation was more noticeable. This could imply that reduced demand for ATP and NADPH in a dark phase of photosynthesis caused a down-regulation of PS2 photochemistry. Furthermore, in leaves of metal-treated plants the decrease in water percentage as well as lower contents of Chl and Fe were observed. Thus photosynthesis is not the main limiting factor for cucumber growth under Cu, Cd, or Pb stress.This revised version was published online in March 2005 with corrections to the page numbers.     

镉、铅及其复合污染对大麦幼苗部分生理指标的影响

以Cd、Pb为胁迫因子,以大麦为试验材料,采用室内培养法,研究了重金属Cd﹑Pb及复合污染不同时间（3、5d）对大麦幼苗叶片部分生理指标的影响。结果表明,随着 Cd﹑Pb及Cd+Pb处理浓度的增加,大麦幼苗叶片中可溶性糖的含量表现为先升后降。在Cd﹑Pb单一处理条件下,不同浓度Cd﹑Pb均可造成叶细胞膜透性增大,叶片的相对电导率和脯氨酸含量上升。不同浓度的Cd+Pb复合处理对叶细胞膜的损伤均大于单一处理,低浓度Cd+Pb（5+50 mg·L^-1）复合处理组的可溶性糖含量比单一处理高。在不同处理时间（3、5d）内,所有Cd+Pb复合处理组叶中脯氨酸含量均高于单一处理组,Cd﹑Pb复合处理对脯氨酸的积累有促进作用。单一处理中Cd对大麦幼苗的毒性比Pb大,而复合处理（Cd+Pb）对大麦幼苗的损伤和毒害作用比单一处理更为严重,其交互作用机理值得进一步研究。     

Effects of Municipal Sewage Sludge Doses on the Chlorophyll Contents and Heavy Metal Concentration of Sugar Beet (Beta vulgaris var. saccharifera)

The present study was conducted to assess the suitability of sewage sludge amendment (SSA) in soil for Beta vulgaris var. saccharifera (sugar beet) by evaluating the heavy metal accumulation and physiological responses of plants grown at a 10%, 25%, and 50% sewage sludge amendment rate. The sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently increasing accumulation in plant parts. Cd, Pb, Ni, and Cu concentrations in roots were significantly higher in plants grown at 25% as compared to 50% SSA; however, Cr and Zn concentration was higher at 50% than 25% SSA. The concentrations of heavy metal showed a trend of Zn > Ni > Cu > Cr > Pb > Cd in roots and Zn > Cu > Ni > Cr > Pb > Cd in leaves. The only instance in which the chlorophyll content did not increase after the sewage sludge treatments was 50%. There were approximately 1.12-fold differences between the control and 50% sewage sludge application for chlorophyll content. The sewage sludge amendment led to a significant increase in Pb, Cr, Cd, Cu, Zn, and Ni concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency (US EPA). The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake and the leaf and root concentrations of Ni, Zn, Cd, Cu, Cr, Pb, and Zn in plants as compared to those grown on unamended soil. More accumulation occurred in roots and leaves than in shoots for most of the heavy metals. The concentrations of Cd, Cr, and Pb were more than the permissible limits of national standards in the edible portion of sugar beet grown on different sewage sludge amendment ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet may not be a good option due to risk of contamination of Cr, Pb, and Cd.     

Determination of element distribution between the symplasm and apoplasm of cucumber plant parts by total reflection X-ray fluorescence spectrometry

The distribution of Cd, Ni, Pb and Fe between the symplasm (cytoplasm) and apoplasm (cell wall) of cucumber roots and leaves was determined by total reflection X-ray fluorescence spectrometry following a special sample preparation procedure. The plants were grown in modified Hoagland nutrient solution containing Fe in chemical form of Fe(III)-citrate or Fe(III)-EDTA, as well as the heavy metal contaminants, each in concentration of 10 microM. In the roots the larger part of Pb was found in the apoplasm, while Ni and Cd were mostly in the symplasm. In the leaves however, about 50-60% of the Pb content and practically the total amount of Cd were detected in the symplasm. About 30-40% of the translocated Ni remained in the apoplasm of the leaves. The Cd-, Ni- and Pb-treatments resulted in higher total concentration of Fe in the roots, however, the relative amount of Fe in the symplasm decreased in all cases. In the leaves of the control plants the larger part (60-80%) of Fe occurs in the symplasm. Due to the heavy metal effects, the relative amount of Fe in the symplasm decreased except in the Pb-contaminated plants, where in the presence of Fe(III)-EDTA, the Pb treatment resulted in a moderate increment of Fe concentration in the symplasm.     

Effects of cadmium, nickel and lead on growth, chlorophyll content and proteins of weeds

The effects of Cd, Ni and Pb on the growth, chlorophyll (Chl) and protein contents, and content of proteases of potted weed plants Cyperus difformis, Chenopodium ambrosioides and Digitaria sanguinolis were determined. The three heavy metals inhibited the shoot growth but were less suppresive to root growth. They also lowered leaf Chl content. The changes in root and shoot protein and proteases contents of weeds were interrelated. The heavy metal additions to soil increased their contents in both roots and shoots, several times more in roots than in shoots. This revised version was published online in July 2006 with corrections to the Cover Date.     

珍稀濒危植物矮牡丹体内矿质元素的研究

采用原子吸收分光光度法测定了矮牡丹体内的10种矿质元素,即K、Mg、Mn、Fe、Ni、Zn、Cu、Cd、Cr、Pb。分析了矿质元素在矮牡丹体内的分布规律及矮牡丹对各种元素的富集能力。结果表明:在不同器官中的矿质元素含量有显著差异, K、Mg、Mn、Ni、Cd、Cr、Pb以叶中为高, Fe、Zn、Cu分别以根、茎、叶柄中含量最高;大多数元素在叶柄中含量最低。矮牡丹对K、Mg、Mn、Fe、Zn有较强的吸收富集能力,一般叶的富集系数较其它器官为高。元素间相关分析表明:Zn、Cd、Cr、Pb、Mn、Fe、Ni、Cu之间有显著的相关性, K、Mg之间的相关性显著。此外,土壤与植物体内元素含量表现出显著的相关性。     

Phytoremediation of Cd, Cr, Cu, Mn, Fe, Ni, Pb and Zn from aqueous solution using Phragmites cummunis, Typha angustifolia and Cyperus esculentus

A comparative bioaccumulation pattern and ultra structural changes were studied in Phragmites cummunis, Typha angustifolia and Cyperus esculentus in mixed metals solution of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). P. cummunis was observed to be a shoot accumulator for Cr, Fe, Mn, Ni, Pb, and Zn. However, T. angustifolia was found to be a root accumulator for Cd, Cr, Cu, Fe, Ni and Pb. In addition, C. esculentus also accumulated most of the tested heavy metals in the roots, while Mn and Fe were translocated up to leaves. Further, the long term metal treatment showed maximum accumulation of all heavy metals in P. cummunis followed by T. angustifolia and C. esculentus. Among heavy metals, Fe was accumulated maximum, i.e., >1000 microg g(-1) by all three plants. Simultaneously, the adverse effects on biochemical parameters were noted earlier in C. esculentus than T. angustifolia and P. cummunis. Ultra structural observation showed the cellular changes in wetland plants after longer exposure. Results revealed that P. cummunis and T. angustifolia had more potential for tested metals than C. esculentus. This study established that these wetland plants could be used for heavy metals phytoremediation from metal containing industrial wastewater.     

Bioaccumulation of heavy metals in Dactylis glomerata L. growing in a calcareous soil amended with sewage sludge

The total and DTPA-extractable concentrations of Pb, Ni, Zn, Cu, Cr and Cd were measured in a calcareous soil amended with different doses of sewage sludge under field conditions. The same metals were also measured in the roots and leaves of Dactylis glomerata at the end of the first vegetative period after the sludge was added. The root concentrations of all the metals were unrelated to their concentrations in the soil. Leaf concentrations of Zn and Cr correlated with total (Zn) and DTPA-extractable (Zn and Cr) concentrations in the soil. DTPA extraction did not appear to be very useful for evaluating the bioavailability of metals in this kind of soil as it gave very low correlation coefficients with leaf content (r = 0.684, P = 0.0049 for Zn and r = 0.557, P = 0.0249 for Cr). Concentrations of Pb, Ni, Cu, and Cd in roots and leaves of Dactylis glomerata were unrelated to the total or DTPA-extractable concentrations in the sludge-amended soil.     

蕹菜典型品种中Cd、Pb、Cr、Ni 等重金属含量及其相关性

目的:蕹菜(Ipomoea aquatica Forsk.)Cd(镉)积累典型品种对Cd、Pb(铅)、C(r铬)、N(i镍)等多种重金属的吸收积累及相互关系。方法:采用盆栽试验,分析4个蕹菜Cd积累典型品种在6种土壤上的两茬茎叶及根Cd、Pb、Cr、Ni含量及相关性。结果:①品种和土壤对供试蕹菜典型品种Cd含量的效应均达显著水平(P<0.05),对Pb、Cr和Ni含量的效应因重金属、收获时期及部位而不同,二者对Cd、Pb含量具一定的交互效应。②两茬茎叶Cd含量平均值均为T308>GDB>QLB>QLQ,根Cd平均含量高于茎叶Cd平均含量;除Cr外,根Pb和Ni平均含量均高于茎叶。③Cd、Pb、Cr、Ni含量呈现复杂的相关关系。茎叶Cd含量与Pb含量正相关,且第一茬相关性极显著(P<0.01);Pb含量与Ni含量相关关系明显,第一茬茎叶、根Pb含量与Ni含量的正相关达到显著(P<0.05)或极显著水平(P<0.01),但第二茬茎叶Pb含量与Ni含量却显著负相关(P<0.05);Pb含量与Cr含量的相关性仅第一茬茎叶显著(P<0.05);Cr含量与Ni含量的相关性仅第二茬茎叶达极显著水平(P<0.01)。结论:蕹菜典型品种对Cd、Pb、Cr、Ni的吸收积累存在协同和拮抗两种作用。     

Potential health risk of selected metals for Polish consumers of oolong tea from the Fujian Province,China

The influence of environmental pollution on the heavy metal content in oolong teas from the Fujian Province, China, and the health risk for the Polish consumers were studied. Average contents of the metals in made oolong tea leaves were (mg kg^?1): Al 1452, Cd 0.08, Co 0.23, Cr 1.59, Cu 10.5, Fe 140, Hg 0.10, Mn 1465, Mo 0.63, Ni 3.45, Pb 1.99, Sb 0.78, Se 5.15, Sn 3.16, Tl 0.28, and Zn 26.9. The metals easily released from leaves to infusions were: Tl, Se, Cd, Sn, Sb, Ni, Al, and Pb. No concentration of As, Hg, Mo, or Pb was found in the first infusion and no As, Co, Hg, or Mo was found in the second one. The hazard quotient values for particular metals found in the infusions and tea leaves and the appraised combined hazard index (HI) amounted to <1. The highest HI values, resulting from the consumption of both infusions, did not exceed 5.88E-03, or 6.94E-04a in the case of tea leaves. No health hazard for the Polish consumers of oolong teas was identified at any of the examined stages of consumption. However, we recommend discarding the first tea infusion to reduce the metal concentrations before consumption.