PLANT BIO-MONITORING OF ORGANIC SOLVENTS IN GROUNDWATER

11th International Multidisciplinary Scientific GeoConference SGEM2011, www.sgem.org, SGEM2011 Conference Proceedings/ ISSN 1314-2704, June 20-25, 2011, Vol. 2, 947-954 pp

ABSTRACT

Leakages from underground storage tanks and accidental spills have led to
contamination of soils and groundwater with organic solvents. Bio-monitoring (phytomonitoring)
uses plant tissue concentrations of organic pollutants in deep-rooted species
of trees for low-cost assessment of the groundwater concentrations. Disadvantages of
this approach include the limited number of said tree species in the contaminated area,
and the limited number of core samples that can be taken from a single tree before it
dies. A solution to this problem was investigated in this study through the use of passive
samplers based on Parafilm M with benzene and trichloroethylene as model solvent
contaminants. The benzene concentrations in the wood peaked at 14 ng/g for Dalbergia
Sisso. For trichloroethylene in the same tree species, the concentration decreased from
the bark into the trunk with a maximum value of 2041 ng/g. In Ficus spp., the
concentration of benzene was independent of the depth in the trunk with one exception.
This was a lack of benzene detection between 10 and 15 cm into the trunk. Concentrations of trichloroethylene peaked between 460 and 662 ng/g and they were observed 5 to 15 cm into the trunk, depending on the species sampled. The amounts of
solvents accumulated in the Parafilm M passive sampler corresponded to the wood and groundwater concentrations; and thus indicate the possible applicability of the proposed
passive sampler in bio-monitoring of groundwater contamination.

Keywords: Parafilm, benzene, trichloroethylene