Moss bag monitoring as screening technique to estimate the relevance of methylated arsine emission.

Volatile arsenic (As) species, like arsine, mono-, di-, and trimethylarsine (AsH3 , MeAsH2 , Me2 AsH, Me3 As) are difficult to sample in remote areas without sophisticated equipment. The application of moss bags is an easy-to-apply screening technique which has been used for trapping total (mostly particulate) As from different emission sources before. We evaluated its potential for additional volatile As species screening. We found Me2 AsH and Me3 As in N2 atmosphere to be quantitatively trapped on the mosses and to be recoverable as their respective pentavalent acids (and/or oxyanions) when ground mosses were heated for 90min at 90°C in 0.1M HNO3 /3% H2 O2 . MeAsH2 was trapped partially while AsH3 was not trapped. The most likely mechanism is covalent bonding to the moss surface. While moss monitoring does not replace more sophisticated techniques for volatile As sampling, it can easily be used as screening technique to determine whether besides particulate As volatile methylated As species could have any relevance in environments with yet unknown As emissions.