Sorption of Cadmium and Zinc in Selected Species of Epigeic Mosses
Andrzej Kos
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Ewelina Gordzielik
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Magorzata Anna Jozwiak
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Magorzata Rajfur
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M. A. Jozwiak Department of Environment Protection and Modelling, Jan Kochanowski University
, ul. S
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A. Kos (&) E. Gordzielik M. Rajfur Opole University
, 6 kard. B. Kominka Str., 45-032 Opole,
Poland
The sorption abilities of seven moss species growing on the area of Bory Stobrawskie forest (southern Poland) were tested in laboratory. Sorption was carried out in solutions of Zn and Cd chlorides. It has been shown that the sorption properties depend on the moss species and increases in the series as follows: Polytrichum commune Leucobryum glaucum Eurhynchium praelongum Thuidium tamtariscifolium B Dicranum scoparium B Pleurozium schreberi Sphagnum sp. With help of microscope images, it was also demonstrated that one of the factors affecting the sorption properties of mosses was the level of their surface development. The determined sorption capacity of Zn varies according to species of mosses from 0.0491 to 0.1287 mmol g-1, and in relation to Cd from 0.0319 to 0.1335 mmol g-1. The described results may be important in the process of biomonitoring research design and in the test results interpretation. Mosses, due to their anatomy and the specific type of nutrition, easily absorb substances contained in atmospheric precipitation. On their surface, in crevices and
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bends, they accumulate dust containing macro- and
micronutrients, which under favorable conditions dissolve in
water that wets the thallus and penetrates its structure. It is
estimated that the surface area of Plagiomnium cuspidatum
and Taxiphyllum deplanatum mosses in proportion to dry
matter is 1.6 m2 g-1 (Darlington et al. 2001). The sorption
intensity depends on the type of absorbed substances,
including the form in which they occur, size, polarity of
molecules or ion charges, and is different for different moss
species. The process of cation sorption, based on the ion
exchange between the moss thallus and a solution that wets
the thallus, is the most known. The ion-exchange process
involves several functional groups, including carboxyl
groups (COOH), aldehyde groups (CHO), hydroxyl
groups (OH) and amino groups (NH2), that form part of
cell wall-forming compounds, such as lignin-like phenolic
compounds (Sen Gupta et al. 2009). Some authors also
point to the possibility of complexing metal ions and the
physical adsorption (Ringqvist et al. 2002).
Good sorption properties of mosses, their prevalence,
simple identification, year-round availability, population
stability and high tolerance to pollutants account for the
fact that mosses, along with lichens, have become the most
widely used material in biomonitoring of the atmospheric
aerosol pollution (Wolterbeek 2002; Markert 2007).
Biomonitoring research involves inter alia analyses of
chemical composition of mosses and/or lichens collected from
their natural habitat (Samecka-Cymerman et al. 2006; Kos
et al. 2010; 2011). Exposure techniques, involving transfer
of the biological material from less polluted areas to urban
or industrial areas, are also frequently used (e.g. Kos et al.
2009; Kosior et al. 2010).
Since 1990, many European countries have been
conducting cyclic (carried out every 5 years) research on trace
elements accumulated in mosses. In 2005, 28 countries,
including Poland, participated in the program (Harmens
et al. 2010). Similar research was conducted in 2000 in the
Visegrad Group countries (Hungary, Czech Republic,
Poland and Slovakia) (Suchara et al. 2007). Due to a large
extent of biomonitoring research, the above studies
incorporate various species of mosses having different sorption
properties and thus, in the case of comparative studies,
false conclusions can often be drawn.
The aim of the study was to evaluate the sorption
properties of seven species of mosses exposed to the
presence of xenobiotic (Cd) and trace element (Zn) and to
check if in natural conditions different species of mosses
absorb the tested metals in accordance with the proportions
experimentally determined in the laboratory.
Materials and Methods
Mosses: Dicranum scoparium, Eurhynchium praelongum,
Leucobryum glaucum, Pleurozium schreberi, Polytrichum
commune, Sphagnum sp. i Thuidium tamtariscifolium,
occurring in Bory Stobrawskie located 2040 km to the
north-west of Opole (Poland) were used in the study.
Green parts of mosses were purified from any
mechanical impurities and then washed with demineralised water
with a conductivity of j = 0.5 lS cm-1. Mosses, dried at
303 K, were stored in sealed plastic containers.
One g dry mass (d.m.) samples were used for tests. Each
species was placed in a perforated 30 cm3 container.
Containers with mosses were placed for 30 min in demineralized
water (2 dm3) to remove salts remaining on the moss surface.
Then seven containers, with mosses prepared as specified
above, were immersed in a 1.4 dm3 solution of salt of the
analyzed metal (Zn and Cd separately). During the (...truncated)