Active biomonitoring of the air quality with terrestrial mosses: standardization and optimization of the technique

Abstract

Terrestrial mosses are excellent biomonitors of air pollution due its physiological and morphological characteristics, and because their use involve a simple and economic technique. The most common type of moss biomonitoring is the use of naturally grown moss in a given area (i.e. native moss). However, sometimes due to the characteristics of the area (eg populated areas and/or industrial areas ), it is very difficult to find native moss, but the use of transplanted moss can solve this problem. In this way, it will be possible to use moss transplants regardless of the level of anthropization the area studied, then calling active versus passive biomonitoring by the uses of native organisms. The “moss bag technique” is the most common type of active biomonitoring with terrestrial mosses that is reported in the literature. The technique consists of the exposure of moss samples held within mesh bags, in order to monitor the occurrence in the air of contaminants. However, although the moss bag technique has been used for 40 years, standardized protocols have unfortunately still not been developed. Such standardized protocols includes: (i) preparation of the moss; (ii) preparation of the transplants; (iii) exposure of the transplants and (iv) post exposure treatment. So the overall objective of this doctoral Thesis is to proposed an harmonised methodology for preparing and exposing moss transplants that meets the following requisites: (i) that the transplants are easy to prepare and handle; (ii) that they enable replicable results to be obtained; (iii) that they are capable of capturing high concentrations of as many contaminants as possible, and (iv) that they are efficient at capturing contaminants, highlighting their occurrence in the air in a reasonable timespan.