Arsenic compounds in terrestrial organisms. IV. Green plants and lichens from an old arsenic smelter site in Austria

Two lichens and 12 green plants growing at a former arsenic roasting facili ty in Austria were analyzed for total arsenic by ICP-MS, and for 12 arsenic compounds (arsenous acid, arsenic acid, dimethylarsinic acid, methylarsoni c acid, arsenobetaine, arsenocholine, trimethylarsine oxide, the tetramethy larsonium cation and four arsenoriboses) by HPLC-ICP-MS. Total arsenic conc entrations were in the range of 0.27 mg As (kg dry mass)(-1) (Vaccinium vit is idaea) to 8.45 mg As (kg dry mass)(-1) (Equisetum pratense). Arsenic com pounds were extracted with two different extractants [water or methanol/wat er (9:1)]. Extraction yields achieved with water [7% (Alectoria ochroleuca) to 71% (Equisetum pratense)] were higher than those with methanol/water (9 :1) [4% (Alectoria ochroleuca) to 22% (Deschampsia cespitosa)]. The differe nces were caused mainly by better extraction of inorganic arsenic (green pl ants) and an arsenoribose (lichens) by water. Inorganic arsenic was detecte d in all extracts. Dimethylarsinic acid was identified in nine green plants . One of the lichens (Alectoria ochroleuca) contained traces of methylarson ic acid, and this compound was also detected in nine of the green plants. A rsenobetaine was a major arsenic compound in extracts of the lichens, but e xcept for traces in the grass Deschampsia cespitosa, it was not detected in the green plants. In contrast to arsenobetaine, trimethylarsine oxide was found in all samples. The tetramethylarsonium cation was identified in the lichen Alectoria ochroleuca and in four green plants. With the exception of the needles of the tree Larix decidua the arsenoribose (2'R)-dimethyl[1-O- (2',3'-dihydroxypropyl)-5-deoxy-beta-D-ribofuranos-5-yl]- arsine oxide was identified at the low mu g kg(-1) level or as a trace in all plants investi gated. In the lichens an unknown arsenic compound, which did not match any of the standard compounds available, was also detected. Arsenocholine and t hree of the arsenoriboses were not detected in the samples. Copyright (C) 2 000 John Wiley & Sons, Ltd.