Research Article

Environmental Science and Pollution Research

, Volume 19, Issue 7, pp 2879-2888

First online:

Salt marsh macrophyte Phragmites australis strategies assessment for its dominance in mercury-contaminated coastal lagoon (Ria de Aveiro, Portugal)

  • Naser A. AnjumAffiliated withCentre for Environmental and Marine Studies (CESAM) and Department of Chemistry, University of Aveiro
  • , Iqbal AhmadAffiliated withCentre for Environmental and Marine Studies (CESAM) and Department of Chemistry, University of AveiroCentre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro Email author 
  • , Mónica VálegaAffiliated withCentre for Environmental and Marine Studies (CESAM) and Department of Chemistry, University of Aveiro
  • , Mário PachecoAffiliated withCentre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro
  • , Etelvina FigueiraAffiliated withDepartment of Biology, Centre for Cell Biology, University of Aveiro
  • , Armando C. DuarteAffiliated withCentre for Environmental and Marine Studies (CESAM) and Department of Chemistry, University of Aveiro
  • , Eduarda PereiraAffiliated withCentre for Environmental and Marine Studies (CESAM) and Department of Chemistry, University of Aveiro

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Introduction and aims

The dominance of a plant species in highly metal-contaminated areas reflects its tolerance or adaptability potential to these scenarios. Hence, plants with high adaptability and/or tolerance to exceptionally high metal-contaminated scenarios may help protect environmental degradation. The present study aimed to assess the strategies adopted by common reed, Phragmites australis for its dominance in highly mercury-contaminated Ria de Aveiro coastal lagoon (Portugal).

Materials and methods

Both plant samples and the sediments vegetated by monospecific stand of Phragmites australis were collected in five replicates from mercury-free (reference) and contaminated sites during low tide between March 2006 and January 2007. The sediments’ physico-chemical traits, plant dry mass, uptake, partitioning, and transfer of mercury were evaluated during growing season (spring, summer, autumn, and winter) of P. australis. Redox potential and pH of the sediment around roots were measured in situ using a WTW-pH 330i meter. Dried sediments were incinerated for 4 h at 500°C for the estimation of organic matter whereas plant samples were oven-dried at 60°C till constant weight for plant dry mass determination. Mercury concentrations in sediments and plant parts were determined by atomic absorption spectrometry with thermal decomposition, using an advanced mercury analyzer (LECO 254) and maintaining the accuracy and precision of the analytical methodologies. In addition, mercury bioaccumulation and translocation factors were also determined to differentiate the accumulation of mercury and its subsequent translocation to plant parts in P. australis.

Results and conclusions

P. australis root exhibited the highest mercury accumulation followed by rhizome and leaves during the reproductive phase (autumn). During the same phase, P. australis exhibited ≈5 times less mercury-translocation factor (0.03 in leaf) when compared with the highest mercury bioaccumulation factor for root (0.14). Moreover, seasonal variations differentially impacted the studied parameters. P. australis’ extraordinary ability to (a) pool the maximum mercury in its roots and rhizomes, (b) protect its leaf against mercury toxicity by adopting the mercury exclusion, and (c) adjust the rhizosphere-sediment environment during the seasonal changes significantly helps to withstand the highly mercury-contaminated Ria de Aveiro lagoon. The current study implies that P. australis has enough potential to be used for mercury stabilization and restoration of sediments/soils rich in mercury as well.

Keywords

Phragmites australis Abundance Mercury Sediments Remediation Exclusion Tolerance