engleski

Ecotoxicity of Biomass Burning Pollutants and Their Nitro Derivatives

Guaiacol (2-methoxyphenol, GUA) is the main component of wood lignin and is essentially emitted to the atmosphere during biomass burning [1]. It is estimated that several hundred tons of GUA are annually released into the troposphere, where the compound partitions between the atmospheric gaseous and aqueous phases and undergoes various aging processes. GUA and its degradation products are then deposited onto the Earth’s surface by dry deposition or precipitation. They can potentially accumulate on surface and reach high concentration locally. The transformation products of GUA are believed to be particularly toxic for living organisms, especially when nitrogen-containing reactive species are involved in the chemistry [2], resulting in the formation of nitroguaiacols (NG). However, no ecotoxicological data for GUA or NG have been reported to date. This study presents the first ecotoxicological study of GUA and its nitrated derivates, namely 4-nitroguaiacol (4NG), 6-nitroguaiacol (6NG) and dinitroguaiacol (DNG), and reveals their harmful potential for the ecosystem [3]. Aquatic toxicities of individual compounds, as well as of their environmentally relevant mixtures, were determined applying Vibrio fischeri bioluminescence acute toxicity test. Individual EC50 values range from 16.7 to 103 mg L−1 after a 30-min incubation period, which classifies all investigated compounds as “harmful” according to the European legislation. No joint actions between the four studied compounds have been observed therefore their concentration addition can be considered for ecotoxicological purposes. However, a synergistic effect between GUA and a minor unidentified first-generation product of its aqueous-phase degradation was observed and should be taken into account when assessing the reaction mixture toxicity. These results highlight the need for further toxicological testing, including organisms of different trophic levels. Thus, besides the bioluminescent bacterium assay, the following tests have been selected: i) immobilization of Daphnia magna ; ii) seed germination inhibition of Trifolium repens and Triticum aestivum, iii) inhibition of Saccharomyces cerevisiae viability, and iv) embryotoxicity of zebrafish. This ongoing investigation will allow to better evaluate the environmental hazard of guaiacol and its nitro derivatives. In addition, other compounds emitted by biomass burning such as catechol and syringol, as well as their main nitration products, will be studied.

Biomass burning ; Pollutants ; Toxicity ; Model organisms

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