The document summarizes a study that investigated using dielectric properties of leaves from the Inula spiraeifolia plant and contaminated water samples to monitor environmental pollution levels. Leaves were collected from a polluted traffic area and unpolluted natural area over three periods. Microwave and radio frequency techniques were applied to measure dielectric properties and detect differences corresponding to pollution levels. The microwave technique provided reliable results showing pollution residue in both plant and water samples over time, while the radio frequency technique was also reliable but not conclusive and requires more study.

1. Ana Patrícia Boavida1, Daniel Gonçalves1, Henrique Cardoso1, Susana Devesa2
1 Class A of the 12th grade, Counselor2
Colégio da Imaculada Conceição (CAIC) , 3044-519, Cernache
Summary
The dielectric properties of leaves of
the inula spiraeifolia plant were
determined with the objective of
investigating their applicability to
monitor environmental pollution. In
parallel, the same technique was
applied to contaminated water with
different concentrations of heavy
metals.
Introduction
Contamination of the environment by heavy metals is responsible for the increase of pollution
and affects different areas of the world. The heavy metals released in the terrestrial environment
tend to concentrate in the soil, becoming a large reservoir available to the roots of the plants,
vulnerable to the concentration variation of these elements. In recent years, the analysis of trace
elements in plant leaves has been used as a potential biomonitoring method. However, chemical
analysis are expensive and time-consuming processes. The innovation of our work is to make
possible the application of two techniques that involve less cost and time than the conventional
ones, allowing to make a monitoring of the environmental contamination with equipment widely
used with other goals.
(Bio)Environmental Monitoring
The video of the work can be seen at: https://www.youtube.com/watch?v=RgKg6VrJbOE
Thanks
To the laboratory New Materials and
Biosystems, of the Department of Physics of
the University of Aveiro.
To João Pedro Carvalho, 11th grade of CAIC.
Collection and preparation of the samples
Figure 1 – (a) Polluted collection zone (IC2);
(b) Non-polluted collection area (QV).
(a) (b)
The leaves of the inula spiraeifolia were collected in a polluted zone of
intense traffic (IC2) and in an unpolluted "natural" area (Quinta do Vale), in
order to verify the different amounts of pollutants in the plants of the two
sites. We did three collections in three different periods, the first collection
being collection A; the second collection, collection B, carried out one month
after collection A; and collection C two months after the previous collection.
In order to investigate the dielectric properties, we applied the Microwave
Technique (MW) in the leaves of inula spiraeifolia and aqueous solutions of
lead and zinc and the Radio Frequency (RF) technique to verify the results
previously obtained in the solid samples.
(a) (b)
(a) (b)
RF Technique
Figure 6 – (a) Sample holder with sample;
(b) Analyzer of impedances.
Figura 7 – ε’ dependence of frequency.
MW Technique
Figure 2 – Resonant Cavity.
Figure 4 – ε’ dependence of the [Pb2+].
Figure 5 – ε’ dependence on the month of collection.
Figure 3 – Press, mold and cylindrical sample.
Conclusion
We conclude that the Microwave Technique is reliable, since we obtained results that show the
presence of pollutant residues in both the aqueous solutions and the plants of the different
collections. The Radio Frequency technique is reliable too, but not conclusive, since in collection B
the QV sample obtained values of ε’ and ε’’ higher than the sample IC2, which would imply a more
in-depth study (more experience time and a greater variety of plant species) for better conclusions.