Elsevier

Chemosphere

Volume 68, Issue 2, June 2007, Pages 323-329
Chemosphere

Uptake and accumulation of cadmium, lead and zinc by Siam weed [Chromolaena odorata (L.) King & Robinson]

https://doi.org/10.1016/j.chemosphere.2006.12.064Get rights and content

Abstract

The Siam weed, Chromolaena odorata (L.) King & Robinson, Family Asteraceae, was found to be a new Pb hyperaccumulator by means of field surveys on Pb soil and hydroponic studies. Plants from field collection accumulated 1377 and 4236 mg kg−1 Pb in their shoots and roots, respectively, and could tolerate soil Pb concentrations up to 100 000 mg kg−1 with a translocation factor of 7.62. Very low concentrations of Cd and Zn were found in plants collected from the field. Under nutrient solution culture condition, C. odorata from the contaminated site (CS) and from non-contaminated site (NCS) grew normally with all three metals (Pb, Cd, Zn) supplied. However, the relative growth rates of all treated plants decreased with increased metal concentrations. The percentage uptakes of Pb, Cd, and Zn by C. odorata increased with increasing metal concentrations. Pb concentration in shoots and roots reached its highest values (1772.3 and 60 655.7 mg kg−1, respectively) at a Pb supply level of 10 mg l−1. While the maximum concentrations of Cd (0.5 mg l−1) in shoots and roots of C. odorata were 102.3 and 1440.9 mg kg−1, and the highest concentrations of Zn (20 mg l−1) were 1876.0 and 7011.8 mg kg−1, respectively. The bioaccumulation coefficients of Pb and Cd were greater than 1000. These results confirm that C. odorata is a hyperaccumulator which grows rapidly, has substantial biomass, wide distribution and has a potential for the phytoremediation of metal contaminated soils.

Introduction

Heavy metals contamination in soil is a major environmental problem. Contamination usually results from industrial activities, such as mining and smelting of metalliferous ores, electroplating, gas exhaust, energy and fuel production, fertilizer and pesticide application, and generation of municipal waste (Kabata-Pendias, 2001). Metal-contaminated soils are notoriously hard to remediate. Current technologies resort to soil excavation and either landfilling or soil washing followed by physical or chemical separation of the contaminants (Prasad, 2004). Unfortunately, these techniques are labor-intensive and costly (Ensley, 2000). In contrast, the use of plants to remove heavy metal contaminants from soils, known as “Phytoremediation”, offers economic and environmental advantages and is a promising technique (Salt et al., 1995). The success of phytoremediation depends on plant growth rate and obtaining high metal concentrations in plant shoots. Plant must produce sufficient biomass while accumulating high concentrations of heavy metals.

In recent years, many plant species, usually those found in heavy metal contaminated areas have been identified as hyperaccumulators, i.e., they have the ability to accumulate unusually high concentrations of heavy metals, without impact on their growth and development (Baker and Brooks, 1989, Xiong, 1997). However, most hyperaccumulators identified so far are not suitable for phytoremediation applications (in the field) due to their small biomass and slow growth (Shen et al., 2002).

Chromolaena odorata (L.) King & Robinson (Asteraceae, Eupatorieae), known as Siam weed, is a perennial shrub that forms dense tangled bushes 1.5–2.0 m in height, occasionally reaching 6 m as a scrambler up trees (McFadyen and Skarratt, 1996). Due to its fast growth rate, and prolific, wind-dispersed seed production, the plants can spread very easily (McFadyen and Skarratt, 1996). C. odorata is widespread throughout Southeast Asia, India, Africa, Australia (McFadyen, 1989, Prasad et al., 1996). It is grown best in areas with a pronounced dry season (McFadyen, 1989). In Thailand, C. odorata is widely distributed throughout the country especially in those areas with a pronounced dry season. C. odorata was found growing commonly on disturbed lead contaminated soils around disused lead mines, at Bo Ngam, Kanchanaburi province, 230 km west of Bangkok. The same species was also found in non-contaminated sites. We hypothesized that the population of this species around the lead mines would have adapted to the contaminated habitat and would differ from the population in non-contaminated sites.

In the present study, a field survey was conducted on C. odorata growing on lead contaminated soil around Bo Ngam lead mine. Hydroponic experiments were then carried out to investigate the differences in growth and heavy metals (Pb, Cd, and Zn) accumulation between C. odorata from contaminated and non-contaminated sites.

Section snippets

Collection and preparation of soil and plant samples from field sites

Bo Ngam lead mine is located in Thongphapum district, Kanchanaburi province, western Thailand. The mine is rich in PbCO3 and was previously operated for 25–30 years before the expiry of the concession in 1996. Samples of C. odorata with soil attached to roots were collected from different sites in Bo Ngam lead mine during October, 2004. These were: site A (ore piling area I), site B (ore piling area II), site C (open pit area), site D (ore dressing plant area). In addition, plants were

Soil metal concentrations and metals uptake and accumulation by plants under field conditions

Soil from site D (ore dressing plant area) had significant higher concentration of all metals, 164 332.7, 1.6, and 260.9 mg kg−1 for Pb, Cd, and Zn, respectively, than other sites (Table 1). There was a close correspondence between extractable Pb contents and the total metal concentrations at each site. C. odorata collected from site D showed the highest Pb and Cd contents in roots (4236 and 0.4 mg kg−1 DW, respectively) and shoots (1376.7 and 0.9 mg kg−1 DW, respectively) (Table 1). C. odorata

Discussion

Markert (1994) gave values of the metal concentration of normal plant with which the uptake in a species could be compared, and showed that the normal compositions of Pb, Cd and Zn in plant are 1, 0.05 and 50 mg kg−1 DW, respectively. Pb is a non-essential element and can be toxic to photosynthesis (Skórzyñska-Polit and Baszyñski, 1997), chlorophyll synthesis (Stobart et al., 1985) and antioxidase enzymes (Somashekaraiah et al., 1992), while Cd inhibits root growth and cell division (Jiang et

Acknowledgements

This research work was supported by the grant from the Post-Graduate Education, Training and Research Program in Environmental Science, Technology and Management under Higher Education Development Project of the Commission on Higher Education, Ministry of Education, and Mahidol University, Bangkok, Thailand. We are grateful to Mr. Philip Round for assistance with the proof reading of the manuscript.

References (44)

  • J.H. Arvik et al.

    The influence of temperature, pH, and metabolic inhibitors on uptake of lead by plant roots

    J. Environ. Qual.

    (1974)
  • A.J.M. Baker et al.

    Terrestrial higher plants which hyperaccumulate metallic elements – a review of their distribution, ecology and phytochemistry

    Biorecovery

    (1989)
  • A.J.M. Baker et al.

    Metal hyperaccumulator plants: a review of the ecology and physiology of a biological resource for phytoremediation of metal-polluted soils

  • P. Bekiaroglou et al.

    The effects of lead and zinc on Mentha spicata

    J. Agron. Crop Sci.

    (2002)
  • E. Delhaize et al.

    Development of three copper metalloenzymes in clover leaves

    Plant Physiol.

    (1985)
  • V. Dushenkov et al.

    Rhizofiltration: the use of plants to remove heavy metals from aqueous streams

    Environ. Sci. Technol.

    (1995)
  • B.D. Ensley

    Rationale for use of phytoremediation

  • M. Greger

    Metal availability, uptake, transport and accumulation in plants

  • B.-D. Hsu et al.

    Toxic effects of copper on photosystem II of spinach chloroplasts

    Plant Physiol.

    (1988)
  • R. Hunt

    Plant Growth Curves

    (1982)
  • A. Kabata-Pendias

    Trace Elements in the Soil and Plants

    (2001)
  • P.S. Kidd et al.

    Tolerance and bioaccumulation of heavy metals in five populations of Cistus ladanifer L. subsp. ladanifer

    Plant Soil

    (2004)
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