Assessing leaf spectral properties of Phragmites australis impacted by acid mine drainage

The decanting of acid mine drainage (AMD) from the Western Basin on the Witwatersrand in late 2010 raised concerns about AMD risks in other gold, coal and copper mining areas of South Africa. Field spectroscopy and the use of vegetation indices could offer an affordable and easy means of monitoring the impact of mine water and/or AMD on vegetation. The impact of raw and treated mine water or contaminated soil on wetland vegetation often manifests in growth inhibition and reduction of foliar pigments and nutrient levels. Surveying the impact on wetland vegetation or underlying soils can be difficult and expensive considering the cost of laboratory analysis of samples. The potential of field spectroscopy for detecting the impact of mine water on wetland vegetation was examined by assessing (1) whether there was a significant difference in leaf spectra between sites receiving mine water and a non-impacted control site and (2) whether there was a gradation of vegetation condition downstream from the decanting site. Two vegetation indices were derived from portable field spectrometer-measured spectra of five green leaves of Phragmites australis - the chlorophyll red edge position (REP) and the normalised difference vegetation index (NDVI) - for two dormant (winter) and peak growth (summer) seasons in 2011-2012. Mean REP and NDVI values were significantly (p<0.05) lower for affected sites compared to the control site for both seasons and years. The range of REP values for young green leaves in winter for affected sites was 695-720 nm compared to the narrower range of 705-721 nm for the control site. The mean REP values for young green leaves in winter was 708 nm for the affected sites compared to 716 nm for the control site. The downstream gradation, however, fluctuated for REP and NDVI over the study period. We conclude that field spectroscopy shows potential to serve as a relatively quick and affordable means to assess the condition and health of vegetation affected by AMD.

[1]  S. Dobrowski,et al.  Steady-state chlorophyll a fluorescence detection from canopy derivative reflectance and double-peak red-edge effects , 2003 .

[2]  M. Osaki,et al.  Beneficial effect of aluminum on growth of plants adapted to low pH soils , 1997 .

[3]  J. Weis,et al.  Release of Metals by the Leaves of the Salt Marsh Grasses Spartina alterniflora and Phragmites australis , 2000 .

[4]  T. McCarthy,et al.  The impact of acid mine drainage in South Africa , 2011 .

[5]  Hui Chen,et al.  Feasibility of estimating heavy metal concentrations in Phragmites australis using laboratory-based hyperspectral data - A case study along Le'an River, China , 2010, Int. J. Appl. Earth Obs. Geoinformation.

[6]  Alexander F. H. Goetz,et al.  Remote sensing for exploration; an overview , 1983 .

[7]  B. Sridhar,et al.  Spectral reflectance and leaf internal structure changes of barley plants due to phytoextraction of zinc and cadmium , 2007 .

[8]  L. Rufo,et al.  Plant communities of extreme acidic waters: The Rio Tinto case , 2011 .

[9]  P. Singer,et al.  Acidic Mine Drainage: The Rate-Determining Step , 1970, Science.

[10]  L. Batty.  Wetland plants - more than just a pretty face? , 2003 .

[11]  A. Baker,et al.  Aluminium and phosphate uptake by Phragmites australis: the role of Fe, Mn and Al root plaques. , 2002, Annals of botany.

[12]  E. Cukrowska,et al.  Acid mine drainage arising from gold mining activity in Johannesburg, South Africa and environs. , 2003, Environmental pollution.

[13]  Corine Davids,et al.  Detecting contamination-induced tree stress within the Chernobyl exclusion zone , 2003 .

[14]  M. Narayan,et al.  The biochemistry of environmental heavy metal uptake by plants: implications for the food chain. , 2009, The international journal of biochemistry & cell biology.

[15]  C. Tucker.  Red and photographic infrared linear combinations for monitoring vegetation , 1979 .

[16]  James Barber,et al.  Effects of heavy metals on the absorbance and reflectance spectra of plants , 1980 .

[17]  J. Clevers,et al.  Study of heavy metal contamination in river floodplains using the red-edge position in spectroscopic data , 2004 .

[18]  D. Deering.  Rangeland reflectance characteristics measured by aircraft and spacecraft sensors , 1979 .

[19]  D. Horler,et al.  The red edge of plant leaf reflectance , 1983 .

[20]  E. Bilal,et al.  Plant availability of uranium in contaminated soil from Crucea Mine (Romania) , 2003 .

[21]  Jianguo Liu,et al.  Accumulation of Cd, Pb and Zn by 19 wetland plant species in constructed wetland. , 2007, Journal of hazardous materials.

[22]  H. Brix,et al.  Accumulation of nutrients and heavy metals in Phragmites australis (Cav.) Trin. ex Steudel and Bolboschoenus maritimus (L.) Palla in a constructed wetland of the Venice lagoon watershed. , 2006, Environmental pollution.

[23]  V. Oros,et al.  STUDIES ON TRANSFER AND BIOACCUMULATION OF HEAVY METALS FROM SOIL INTO LETTUCE , 2008 .

[24]  M. Burchett,et al.  Accumulation and distribution of heavy metals in the grey mangrove, Avicennia marina (Forsk)Vierh: biological indication potential. , 2003, Environmental pollution.

[25]  James Barber,et al.  Approaches to detection of geochemical stress in vegetation , 1983 .

[26]  M. Bernal,et al.  Tolerance and bioaccumulation of cadmium by Phragmites australis grown in the presence of elevated concentrations of cadmium, copper, and zinc , 2004 .

[27]  L. Debán,et al.  Effects of selected trace elements on plant growth , 1990 .

[28]  P. Curran.  Remote sensing of foliar chemistry , 1989 .

[29]  M. Schiavon,et al.  Seasonal variations of Cu, Zn, Ni and Cr concentration in Phragmites australis (Cav.) Trin ex steudel in a constructed wetland of North Italy , 2009 .

[30]  F. Gomes,et al.  Tolerance and prospection of phytoremediator woody species of Cd, Pb, Cu and Cr , 2007 .

[31]  He Wang,et al.  Bioaccumulation of heavy metals by Phragmites australis cultivated in synthesized substrates. , 2009, Journal of environmental sciences.

[32]  M. Cho,et al.  A new technique for extracting the red edge position from hyperspectral data: The linear extrapolation method , 2006 .

[33]  J. Vymazal,et al.  Trace metals in Phragmites australis and Phalaris arundinacea growing in constructed and natural wetlands. , 2007, The Science of the total environment.

[34]  Z. Xiong,et al.  Bioaccumulation and ecophysiological responses to copper stress in two populations of Rumex dentatus L. from Cu contaminated and non-contaminated sites , 2004 .

[35]  M. Wong,et al.  Accumulation of lead, zinc, copper and cadmium by 12 wetland plant species thriving in metal-contaminated sites in China. , 2004, Environmental pollution.

[36]  J. A. Schell,et al.  Monitoring vegetation systems in the great plains with ERTS , 1973 .

[37]  Meiling Liu,et al.  Monitoring stress levels on rice with heavy metal pollution from hyperspectral reflectance data using wavelet-fractal analysis , 2011, Int. J. Appl. Earth Obs. Geoinformation.

[38]  P. Younger,et al.  The effect of pH on plant litter decomposition and metal cycling in wetland mesocosms supplied with mine drainage. , 2007, Chemosphere.

[39]  P. Schröder,et al.  Dualities in plant tolerance to pollutants and their uptake and translocation to the upper plant parts , 2009 .

[40]  J. H. Peverly,et al.  Growth and trace metal absorption by Phragmites australis in wetlands constructed for landfill leachate treatment , 1995 .