ADSORPTION TO CHITIN – A VIABLE AND ORGANISM-PROTECTING METHOD FOR BIOMONITORING METALS PRESENT IN DIFFERENT ENVIRONMENTAL COMPARTMENTS GETTING CONTACTED WITH ARTHROPODS

Abstract

Among the various biopolymers which cover outer interfaces of organisms, chitin is the most abundant: each year several billion metric tons (possibly even much more) are produced by arthropods and processed in soil and litter, wet sediment  (especially in moist soils while otherwise chitin samples can persist virtually unchanged for geological periods of time). Moreover, arthropods, among which Coleoptera are represented by some 400,000 species alone, inhabit almost all ecosystems, way beyond the ecological range of, say, mosses. Given that adsorption of metalliferous analytes (ions, volatile compounds, complexes of whatever net charge) to chitin obtained from arthropods can be demonstrated (and it partly was already), it is feasible to obtain data on environmental element contents in all water, soil and gas phase (atmosphere) by dissolving, analyzing outermost (part of exocuticle) chitin layers. Data on relative uptake contributions/environmental burdens of either compartment can be obtained by both interspecies-comparisons and sampling of different parts of some larger arthropod (abdomen-, outer- and inner wing surfaces of sizable beetles). As just a very thin chitin layer (< 2 µm) is ablated from the animal´s outer surface by dissolution using little toxic components, sampling will not cause harm to them, enabling a) repeated sampling of the same specimen (e.g. for taking t = 0 starting values) and b) use of rare or/and protected species. Applications are with both biomonitoring and a better understanding of metal ion transport in ecosystems, e.g. concerning interfacial Mⁿ⁺ binding to dying zooplankton then sinking below the chemokline of euxinic water bodies. An indirect metal levels monitoring of woody plants and underneath soils also appears feasible.