Disaster Advances Vol. 6 (S3) July 2013

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1 Dsaster Advances Vol. 6 (S3) July 2013 Assessment of the potental ecologcal rsk of heavy metals n reclamed sols at an opencast coal mne Jnman Wang 1,2*, Wehong Lu 1, Ruxuan Yang 1, Lng Zhang 1, Janjun Ma 3 1.ollege of Land Scence and Technology of hna Unversty of Geoscences, 29 Xueyuanlu, Handan Dstrct, Bejng, People s Republc of hna 2.Key Laboratory of Land onsoldaton and Land Rehabltaton Mnstry of Land and Resources, Bejng, People s Republc of hna 3.Langfang Teacher s ollege, Langfang, Hebe, People s Republc of hna * wangjnman2002@163.com Abstract To reveal the potental polluton characterstcs of heavy metals n reclamed sols at the Hedagou opencast coal mne, the Hakanson potental ecologcal rsk and Nemerow mult-factor ndces were used to analyze d, Hg, As, Pb, r, u, Zn and N contamnaton and assess the correspondng ecologcal rsk. The two ndces revealed smlar levels of heavy metal polluton, ndcatng that the mne ste s contamnated by the heavy metals to varyng degrees compared to the background values for the orgnal landform. Although the overall contamnaton s moderate, the mne ste contans hgh levels of Hg and Pb polluton. Measures should thus be taken to control the heavy metal contamnaton n the sols at the Hedagou coal mne, to strengthen the ecologcal restoraton and envronmental protecton at the ste. Keywords: land reclamaton, Hedagou opencast coal mne, sol heavy metal, contamnaton rsk assessment Introducton Mneral resources are abundant n hna. In recent years, the explotaton of coal resources has greatly enhanced hna s socal and economc development. At the same tme, however, surface mnng s a major cause of envronmental damage. Surface mnng, especally opencast coal mnng, damages the surface vegetaton and sol and changes the herarchcal structure of natural sols. As a result, a seres of sol qualty degradaton problems have appeared n hna s coal mnng areas, ncludng heavy metal sol contamnaton, whch s a major lmtng factor affectng sol qualty. Varyng levels of heavy metals tend to accumulate n coal mnng areas. In addton to damagng the structure, functon, and qualty of sols, ths heavy metal contamnaton drectly affects human health and development. The sol heavy metals n the envronment are relatvely stable and are dffcult to remove through natural processes 1. Therefore, the montorng and assessment of the envronmental qualty of sols plays an mportant role n restorng damaged ecosystems, protectng sol envronmental qualty, and developng a scentfc bass for sustanable coal mnng 2. The envronmental problems caused by mnng have attracted a great deal of research attenton 3-6. In recent years, numerous sol heavy metal contamnaton assessment methods have been developed, ncludng the ndex method, the dynamc assessment method, the lfe cycle assessment method, the GIS based sol qualty assessment method, the contamnaton loss rate method, the osculatng value method, and the synthess methods n chemstry, ecology, and toxcology, etc In ths study, the Hakanson potental ecologcal rsk ndex method and the Nemerow mult-factor ndex method were used to assess the potental ecologcal rsk assocated wth 8 heavy metals found n the reclamed sol at the Hedagou opencast coal mne. The contamnaton assessment was conducted to provde reasonable evdence on sol remedaton and protecton for the related department. Study regon The Hedagou opencast coal mne s located n the east of Junggar Banner n Erdos ty, 130 km south of Hohhot. The elevaton at the mne ranges between 1,025 m and 1,302 m, and the geographc coordnates are ~39 49 N and ~ E. The study area s part of the Loess regon, bordered by Shanx, Shaanx, and Inner Mongola (Fg. 1). The area s n a temperate contnental ard clmate zone that s cold n wnter, dry and wndy n sprng, hot n summer, and mld and pleasant n autumn. The annual average temperature s 7.2, the average annual ranfall s mm, the (366)

2 Dsaster Advances Vol. 6 (S3) July 2013 average annual evaporaton s 1,943.6 mm, and the relatve humdty s 58%. The wnd s mostly calm, flowng n a north-northwest drecton at an average speed of 2.2 m/s. The coal mne s stuated n a typcal steppe ecologcal regon, wth Stpa speces comprsng the man vegetaton. onstructon of the mne began n The mne has sx dumps, known as the North, East, West, Internal, East Yanbang, and Ynwan dumps. The frst fve dumps are n dfferent stages of rehabltaton and contan a range of vegetaton, ncludng tabulaeforms, Robna, Sabna vulgars, typhna, Amorpha, weepng wllows, Syrnga retculata Hong and other arbors, sand spnes, flowerng plum, aprcot and other shrubs, and alfalfa adsurgens, lcorce and other herbs. Fg.1 The study area locaton Materals and methods Sol sample collecton and processng Sol samples were collected from 10 typcal dump stes at the Hedagou opencast coal mne accordng to the varyng years of reclamaton and vegetaton dstrbuton patterns, and ncludng stes that had not been reclamed. Samples of undsturbed sol n the orgnal landform were taken as a control. The 0-30 cm surface sol samples were collected usng the mxng method. The sample weght of 500g was obtaned by the quarterng method after homogeneous mxng. The man sol physcochemcal propertes and heavy metals elements were determned after ar-dryng, removng the plant resdue and stone block, grndng and sevng. The condtons of the sample plots are shown n Table 1 (367)

3 Dsaster Advances Vol. 6 (S3) July 2013 Table 1 ondtons of sample plots Plot Reclamaton Sol Ste Reclamaton vegetaton type NO. years/a texture 1 Ynwan dump - - lght loam 2 Internal dump - Populus sp., aragana korshnsk lght loam 3 East Yanbang dump 7 Pnus tabulaeforms, Prunus armenaca lght loam 4 West dump 13 Hppophae rhamnodes, alamagrosts brachytrcha, Poa pratenss lght loam 5 East dump I 15 Populus sp., Glycyrrhza lght loam 6 East dump II 15 Populus sp., Glycyrrhza lght loam 7 North dump I 18 alamagrosts brachytrcha, Leymus secalnus, Medcago satva, Prunus armenaca lght loam 8 North dump II 18 alamagrosts brachytrcha, Leymus secalnus, Medcago satva, Prunus armenaca lght loam 9 Daosuangou dump 18 Pnus tabulaeforms, Populus sp. lght loam 10 Orgnal landform - aragana korshnsk, Aprcot lght loam Determnaton of sol physcochemcal propertes Sol organc matter (OM) was determned by the potassum bchromate ttrmetrc method, sol total ntrogen (TN) was determned by the sem-mcro Kjeldahl method, total phosphorus (TP) was determned by the alkal fuson Mo-Sb antspetrophotography method, total potassum (TK) was determned by the alkal fuson flame photometry method, hydrolyzable ntrogen (HN) was determned by the acd-soluble. Mo-Sb antspetrophotography method, avalable phosphorus (AP) was determned by the sodum bcarbonate extracton Mo-Sb antspetrophotography method, and avalable potassum (AK) was determned by the ammonum carbonate extracton-flame photometry method. The physcal and chemcal propertes of the sol samples from the mnng area are shown n Table 2 Table 2 Physcal and chemcal propertes of the sol n the mnng area Plot NO. Ste OM TN TP TK HN AP AK (g/kg) (g/kg) (g/kg) (g/kg) (mg/kg) (mg/kg) ( mg/kg) 1 Ynwan dump Internal dump East Yanbang dump West dump East dump I East dump II North dump I North dump II Daosuangou dump Orgnal landform Analyss and determnaton of heavy metals The sol samples were dgested by the full decomposton method wth hydrochlorc acd, ntrc acd, hydrofluorc acd, and perchlorc acd. u, Zn, N, and r were determned wth flame atomc absorpton spectrophotometry, Pb and d were determned by the (368)

4 Dsaster Advances Vol. 6 (S3) July 2013 F-ass method, Hg was determned by cold vapor atomc between 9.69 and 15.8 mg/kg, wth average value of absorpton spectrometry, and As was determned by the mg/kg, and the values of all the Pb samples were dethyl dthocarbamate slver spectrophotometry method. above that of the sol background. The mass fracton of d, Hg, As, Pb, r, u, Zn, and N were measured wth r was between 54.1 and 77.6 mg/kg, wth an average an atomc absorpton spectrophotometer (the Shmadzu value of mg/kg, and the values of 6 of the r AA- 6601F type). samples were above that of the sol background. The mass fracton of u was between 13.4 and 23.2 mg/kg, The sol dstrbuton characterstcs of the heavy wth an average value of mg/kg, and the values of metals n the study area are shown n Table 3. The mass 9 of the u samples were above that of the sol fracton of d was between 0.03 and 0.09 mg/kg, wth an background. The mass fracton of Zn was between 48.9 average value of 0.06 mg/kg, and the values of 6 of the and 67.4 mg/kg, wth an average value of mg/kg, d samples were above that of the sol background. The and the values of all the Zn samples were above that of mass fracton of Hg was between 0.01 and 0.05 mg/kg, the sol background. The mass fracton of N was wth an average value of 0.02 mg/kg, and the values of 9 between 24.6 and 34.2 mg/kg, wth an average value of of the Hg samples were above that of the sol mg/kg, and the values of all the N samples were background. The mass fracton of As was between 6.92 above that of the sol background. None of the 8 heavy and mg/kg, wth an average value of 8.89 mg/kg, metals had sol concentratons greater than the levels and the values of 4 of the As samples were above that of stpulated by the Sol Envronmental Qualty Standard the sol background. The mass fracton of Pb was Regulatons 18. Table 3 oncentraton of heavy metals Plot Reclamaton Mass fractons of heavy metals/(mg/kg) Ste NO. years/a d Hg As Pb r u Zn N 1 Ynwan dump Internal dump East Yanbang dump West dump East dump I East dump II North dump I North dump II Daosuangou dump Orgnal landform sol envronmental background values sol envronmental qualty standard average value Selecton of the assessment method and determnaton of the parameters The Hakanson potental ecologcal rsk method and the Nemerow ntegrated ndex method were used to assess the sol qualty and the potental ecologcal rsk of the heavy metal contamnaton. The 8 heavy metal elements, namely d, Hg, As, Pb, r, u, Zn, and N, were selected to evaluate the local contamnaton characterstcs. Hakanson potental ecologcal rsk method The potental ecologcal rsk ndex method was proposed by Hakanson from a sedmentology perspectve to assess the characterstcs and envronmental behavor of heavy metal contamnants n sol sedments. In addton to consderng the heavy metals n sol, the Hakanson method assesses ther potental ecologcal and envronmental effects wth toxcology. The assessment, whch s conducted usng parallel and equvalent ndex classfcaton, provdes a quanttatve method of drectly (369)

5 Dsaster Advances Vol. 6 (S3) July 2013 solatng the extent of potental hazards. Ths method s able to reflect the effects of varous contamnants and reveal the comprehensve nfluence of multple contamnants n a partcular envronment. At present, the Hakanson method s the most scentfc and comprehensve approach to assessng heavy metal contamnaton n sols. The method comprses a sngle contamnaton coeffcent, a comprehensve contamnaton measure, the toxc response factor for heavy metals, and a potental ecologcal rsk ndex. The specfc calculatng formulas are as follows: The sngle contamnaton coeffcent /, f sl where n a partcular heavy metal, f s the contamnaton coeffcent of sl s the measured data of sol heavy metals, and n s the reference value. The comprehensve contamnaton measure. d f The potental ecologcal rsk ndex of a partcular heavy metal where s RI. E r T, r T r s the toxc response factor. The potental ecologcal rsk ndex E r The correspondng degrees of contamnaton and the gradng standards for the levels of potental ecologcal rsk n f, d, relevant studes are shown n Table 4. f E r, and RI based on Table 4 Degree of contamnaton for partcular heavy metals and the correspondng gradng standards for potental f ecologcal rsk <1,non- contamnaton 1,<2,lght 2,<3,moderate 3,heavy d <8,low 8,<16,moderate 16,<32,relatvely hgh 32,very hgh E r <40,low 40,<80,moderate 80,<100,strong 100,<320,very strong 320,extremely strong RI <150,low 150,<300,moderate 300,<600,strong 600,very strong The reference values for assessng sol heavy metals vary greatly. Some studes adopted the average content of shale heavy metals as the unform heavy metal reference values n sedments, some used the average global sedment heavy metal content as the reference value 22-24, whle others selected the natonal sol envronment qualty standard (level 2) as the reference value Hakanson proposed the hghest values of the heavy metals n sedments before the modern ndustral era as reference values 27. In ths study, the background values were used as the reference values to accurately reflect the polluton levels at the Hedagou opencast coal mne. The toxc response factor represents the potental hazard of heavy metal contamnaton by ndcatng the toxcty of partcular heavy metals and the envronmental senstvty to contamnaton. The toxc response factor was determned accordng to the elements abundance prncple and the elements release prncple of Hakanson et al. Accordng to the standardzed toxc response factor proposed by Hakanson et al. 28, d, Hg, As, Pb, r, u, Zn, and N have toxc response factors of 30, 40, 10, 5, 2, 5, 1, and 5, respectvely. Nemerow mult-factor ndex method A sub-ndex of each contamnant was calculated by comparng the measured value of each heavy metal n the sol samplng area wth the evaluaton standard. As the sub-ndex can be used to calculate the sngle factor and mult-factor comprehensve polluton ndces of sol heavy metals, the stuaton at the Hedagou mne was analyzed based on the sub-ndex, the sngle factor contamnaton ndex, and mult-factor comprehensve contamnaton ndex In addton to synthetcally and objectvely reflectng the degree of contamnaton of dfferent elements, the comprehensve contamnaton (370)

6 Dsaster Advances Vol. 6 (S3) July 2013 ndex s able to hghlght the effects of hgh concentratons of contamnants on envronmental sol qualty. Therefore, the comprehensve polluton ndex provdes a more scentfc representaton of sol contamnants and sol envronmental qualty. The sngle contamnaton ndex P / S, where contamnants, P s the contamnaton ndex of sol contamnants n mg/kg, and s the measured value of sol S s the background value of sol contamnants n mg/kg. The background values are used as the reference values n ths study to accurately reflect the levels of contamnaton n the sol at the Hedagou opencast coal mne. P P, the more serous the sol contamnaton. The Nemerow mult-factor ndex 2 2 S / S / 2 1 / 2, where / ave max P s the comprehensve contamnaton ndex of the sol contamnants, / S ave s the average value of the polluton ndex of sol contamnants, and S s the maxmum value of the sngle / max contamnaton ndex. The sol polluton grade standard s based on the Tral Implementaton Outlne for Assessment of Envronmental Qualty of Green Food Growng Areas, whch was compled n 1994 (Table 5). The sol s not contamnated when P 1, but s contamnated when P 1, and the hgher the Table 5 lassfcaton crtera for the comprehensve sol assessment Grade dvson P ontamnaton level ontamnaton degree 1 P 0.7 safe clean 2 0.7<P 1 alert stll clean 3 1<P 2 lght contamnaton sol slghtly contamnated, crops begnnng to be contamnated 4 2<P 3 moderate contamnaton sol and crops moderately contamnated 5 P >3 severe contamnaton sol and crops serously contamnated Results Hakanson potental ecologcal rsk method The degree of sol contamnaton degree at the Hedagou opencast coal mne ranged from 9.14 to 12.50, wth an average value of 10.37, reflectng moderate contamnaton, as shown n Table 6. The order of contamnaton of the 8 heavy metals s, Hg>Pb>N> Zn>u>d>r>As, and the order of contamnaton at the stes s, West dump>east dump II>Ynwan dump >North dump I>Orgnal landform>north dump II> Daosuangou dump > East Yanbang dump > Internal dump>east dump I. The average value of the 8 heavy metal contamnaton coeffcents was between 1.00 and 1.99, ndcatng a slght level of contamnaton. Hg had the largest contamnaton coeffcent, especally n the West dump (4.5) and East dump II (3.2), ndcatng severe contamnaton. Therefore, targeted polluton control and management measures are urgently requred to prevent the ncrease of Hg contamnaton and to lmt potental harm. The degree of contamnaton of Hg n the orgnal landform was 2.4, whch ndcates a moderate level of contamnaton. (371)

7 Dsaster Advances Vol. 6 (S3) July 2013 There was no regularty n the changes n the reclamaton ncreased or for dfferent vegetaton types. varous metal contamnaton coeffcents as the years of Table 6 ontamnaton ndces and the overall contamnaton of heavy metals n the reclamed sols Plot ontamnaton Ste d NO. d Hg As Pb r u Zn N level 1 Ynwan dump moderate 2 Internal dump moderate 3 East Yanbang dump moderate 4 West dump moderate 5 East dump I moderate 6 East dump II moderate 7 North dump I moderate 8 North dump II moderate 9 Daosuangou dump moderate 10 Orgnal landform moderate Average value moderate ontamnaton degree lght lght lght lght lght lght lght lght moderate f The potental ecologcal rsk ndex of the heavy metals n the sol at the Hedagou opencast coal mne was calculated accordng to the Hakanson ndex method and ts dvson standard, and the results are shown n Table 7. The rsk coeffcents of d n most of the sol samples were slght. The rsk coeffcents of the sols n the Ynwan dump, North dump I, and North dump II were moderate. Of the 8 heavy metals, the level of Hg contamnaton posed the most serous potental ecologcal rsk, wth an ndex of between 40 and 180. The rsk coeffcent of each reclamed sol sample was ether moderate or above. The rsk coeffcents of some of the reclamed sols were hgh, although the mean value was 79.60, whch ndcates moderate rsk. Hg polluton was the man problem n the study area, wth the overall Hg content ndcatng a moderate degree of contamnaton. In other words, effectve control of Hg emssons s necessary. The rsk coeffcents of As, Pb, r, N, u, and Zn at each ste were all low, ndcatng that these 6 knds of heavy metals had a lmted envronmental mpact at the Hedagou opencast coal mne. Judgng from the total polluton level, the order of ecologcal rsk assocated wth the 8 heavy metals s Hg>d>As>Pb>N>u>r>Zn. Hg has the hghest potental ecologcal rsk ndex and poses the greatest damage to the reclamed sol and the orgnal landform. Because Zn plays an mportant role n plant nutrton and has a relatvely lower toxcty response factor, t presents the least ecologcal hazard. The potental ecologcal rsk ndex s a comprehensve measure of the degree of contamnaton and potental ecologcal hazard of the 8 heavy metals. The potental ecologcal rsk ndces of the heavy metals found at the Hedagou opencast coal mne ranged from to , wth an average value of , representng a slght ecologcal rsk. Therefore, the contamnaton control and comprehensve treatment of heavy metals at the mne should be strengthened, especally for Hg, to mprove the ecologcal restoraton and envronmental protecton at the ste. (372)

8 Dsaster Advances Vol. 6 (S3) July 2013 Table 7 Ecologcal rsk factor and potental ecologcal rsk ndex of heavy metals n the mnng area Plot Potental ecologcal rsk factor E Ste r Rsk RI NO d Hg As Pb r u Zn N grade 1 Ynwan dump lght 2 Internal dump lght 3 East Yanbang dump lght 4 West dump moderate 5 East dump I lght 6 East dump II moderate 7 North dump I moderate 8 North dump II lght 9 Daosuangou dump lght 10 Orgnal landform lght average value lght potental ecologcal rsk lght moderate lght lght lght lght lght lght lght Nemerow mult-factor ndex method The assessment results from the Nemerow mult-factor ndex method are shown n Table 8. The varaton coeffcents n d and Hg were 33.33% and 50%, respectvely, ndcatng that there may be contamnaton sources for these metals n the Hedagou opencast coal mne, whch would requre close attenton. The proporton above the standard value n d, Hg, As, Pb, r, u, Zn, and N were 60%, 90%, 40%, 100%, 60%, 90%, 100%, and 100%, respectvely. ompared wth the orgnal landform, dfferent degrees of contamnaton exst n the reclamed sols at the Hedagou opencast coal mne. The sngle contamnaton ndex only reflects the contamnaton of sngle heavy metals. However, n the natural envronment, heavy metal contamnaton s always concomtant and combned. Therefore, the comprehensve contamnaton ndex provdes the only concrete evaluaton of the overall polluton (Fg. 2). The comprehensve contamnaton ndex for East dump II was 2.48, whch ndcates a moderate degree of contamnaton. The comprehensve polluton ndex for the West dump was 3.36, ndcatng a hgh level of contamnaton, whch should be gven suffcent attenton. For the other reclamed sols, the comprehensve polluton ndces ranged from 1.22 to 1.91, ndcatng lght contamnaton. The order of the degrees of comprehensve heavy metal polluton at the varous stes are West dump>east dump II>Orgnal landform> Ynwan dump>north dump I>Daosuangou dump> East Yanbang dump>north dump II>Internal dump> East dump I. Accordng to the overall assessment results, the comprehensve polluton ndex of sol heavy metals at the Hedagou opencast coal mne was 2.72, ndcatng a moderate level of contamnaton. The order of the comprehensve contamnaton ndces for the 8 heavy metals s Hg>Pb>N>d>u>Zn>As>r. Table 8 Results of the analyss and assessment of heavy metals n the reclamed sols Assessment factor d Hg As Pb r u Zn N average value/(mg/kg) assessment standard/(mg/kg) over standard rate/% range/(mg/kg) standard devaton /(mg/kg) varaton coeffcent /% P P 2.72 (373)

9 Dsaster Advances Vol. 6 (S3) July 2013 Dscusson It s essental to assess the levels of heavy metals n sols to control the ncreasng levels of heavy metal contamnaton. There are many dfferent methods and ndces for evaluatng sol heavy metal contamnaton, ncludng the Hakanson potental ecologcal rsk ndex and the Nemerow mult-factor ndex 22,28. The results of these two methods showed some dfferences n the polluton rsk of sngle heavy metals, whch reflect ther dfferent calculaton means and focus content. Fg. 2 Sol contamnaton ndces of the heavy metals n the studed regon The Hakanson potental ecologcal rsk ndex s based on a comprehensve consderaton of the ecologcal and envronmental effects and toxcology of the heavy metals n sols. The parallel and equvalent ndex classfcaton methods reflect the nfluence of varous specfc contamnants and the comprehensve nfluence of dfferent contamnants on the envronment. The Hakanson ndex also provdes a quanttatve method of drectly solatng the extent of potental hazards. However, one drawback of ths approach s that t nvolves a hgh level of subjectvty and neglects the weghtng role or combned antagonsm of varous heavy metals. Overall, the potental ecologcal rsk ndex and sngle heavy metal contamnaton ndex yelded dfferent assessment results. The sngle heavy metal contamnaton ndex was able to hghlght the harm that Hg and d posed to the human body and the ecosystem. Alternatvely, the Nemerow mult-factor ndex was able to reflect the effects of the heavy metals on the sol and stress the overall envronmental mpact of hgh concentratons of heavy metals. Ths approach also avoded the occurrence of average effects, whch weaken the weght values of heavy metals. However, as the effects of hgh and low concentratons of elements may be exaggerated or reduced durng assessment, the results may devate from the objectve crcumstances (374)

10 Dsaster Advances Vol. 6 (S3) July 2013 In sum, dfferent evaluaton ndces and evaluaton methods should be selected for dfferent purposes and scales. The comprehensve comparson of varous methods can reduce errors and ncrease accuracy. oncluson The Hakanson potental ecologcal rsk ndex and the Nemerow mult-factor ndex were used to analyze the mass fractons of d, Hg, As, Pb, r, u, Zn, and N n sol samples from the Hedagou opencast coal mne, and the levels of contamnaton and the potental ecologcal toxcty of the heavy metals n the reclamed sols were obtaned. (1) The Hakanson potental ecologcal rsk ndex ndcated that the overall polluton n the reclamed sols at the Hedagou opencast coal mne was moderate. Materally, the 8 heavy metals had lght levels of contamnaton. The order of contamnaton of the 8 heavy metals s, Hg>Pb>N>Zn>u>d>r>As. In terms of the actual level of contamnaton, Hg had the hghest toxc response factor and represented the greatest ecologcal hazard. Therefore, some measures should be taken to control the heavy metal contamnaton n the sol at the opencast coal mne, especally for Hg, to strengthen the ecologcal restoraton and envronmental protecton at the ste. (2) The Nemerow mult-factor ndex ndcated that the Hedagou opencast coal mne s contamnated by the 8 heavy metals to dfferent degrees. The assessment results revealed heavy Hg contamnaton and lght contamnaton by the other heavy metals. The order of heavy metal comprehensve polluton s Hg>Pb>N> d>u>zn>as>r. n the sol at the Hedagou opencast coal mne, especally for Hg and Pb, to strengthen the ecologcal restoraton and envronmental protecton at the ste. Acknowledgments Ths research was supported by Natonal Natural Scence Foundaton of hna ( ) and the Fundamental Research Funds for the entral Unverstes of hna. References 1. Gergen I., Harmanescu M., Applcaton of prncpal component analyss n the polluton assessment wth heavy metals of vegetable food chan n the old mnng areas, hemstry entral Journal, 6, 156 (2012) 2. Mn X., Xe X., ha L., Lang Y., L M., Ke Y., Envronmental avalablty and ecologcal rsk assessment of heavy metals n znc leachng resdue, Transactons of Nonferrous Metals Socety of hna, 23(1), (2013) 3. ao D., Wang G., Wang Y., Xang J., S Y., Accumulaton of heavy metals n domnant plants growng on mneral areas n Anhu Tonglng, Journal of Agro-Envronment Scence, 24(6), (2005) 4. Le M., Yue Q., hen T., Huang Z., Lao X., Lu Y., Zheng G., hang Q., Heavy metal concentratons n sols and plants around Shzhuyuan area of Hu nan Provnce, Acta Ecologcal Snca, 25(5), (2005) 5. Rodrcguez F. G. M., Shumln E., Sclnchez R. I., Heavy metal polluton montorng usng the brown seaweed Padna durvllae n the coastal zone of the Santa Rosalca mnng regon, Baja alforna Pennsula, Mexco, Journal of Appled Phycology, 21(1), (2009) (3) The Hakanson potental ecologcal rsk ndex and the Nemerow mult-factor ndex produced smlar measures for the levels of sol heavy metal polluton at the Hedagou opencast coal mne and thereby confrm each other s results. 6. Yu J. Lu J., Wang J., L Z., Zhang X., Spatal-temporal varaton of heavy metal elements content n coverng sol of reclamaton area n Fushun coal mne, hnese Geographcal Scence, 12(3), (2002) (4) Measures need to be ntroduced to comprehensvely control the heavy metal contamnaton 7. MagedM., Hand probably senstvty analyss publc health rsk assocaton from contamnated, Sol ontamnated, (375)

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