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

Abstract

Two lichens and 12 green plants growing at a former arsenic roasting facility in Austria were analyzed for total arsenic by ICP-MS, and for 12 arsenic compounds (arsenous acid, arsenic acid, dimethylarsinic acid, methylarsonic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, the tetramethylarsonium cation and four arsenoriboses) by HPLC-ICP-MS. Total arsenic concentrations were in the range of 0.27 mg As (kg dry mass) À1 (Vaccinium vitis idaea) to 8.45 mg As (kg dry mass) À1 (Equisetum pratense). Arsenic compounds were extracted with two different extractants [water or methanol/water (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 differences were caused mainly by better extraction of inorganic arsenic (green plants) and an arsenoribose (lichens) by water. Inorganic arsenic was detected in all extracts. Dimethylarsinic acid was identified in nine green plants. One of the lichens (Alectoria ochroleuca) contained traces of methylarsonic acid, and this compound was also detected in nine of the green plants. Arsenobetaine was a major arsenic compound in extracts of the lichens, but except 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-b-D-ribofuranos-5-yl]-arsine oxide was identified at the low mg kg À1 level or as a trace in all plants investigated. In the lichens an unknown arsenic compound, which did not match any of the standard compounds available, was also detected. Arsenocholine and three of the arsenoriboses were not detected in the samples.

Metal and metalloid speciation in plants: Overview, instrumentation, approaches and commonly assessed elements

“…Some of the challenges surrounding homogenization can be addressed by drying or freezing samples prior to this step; increasing the ease by which homogenization can take place, and ending microbial activity which may otherwise disrupt the chemical equilibrium between species. Commonly employed techniques are air drying [15; 58], oven-drying [63], freezing to between -20°C to -80 ˚C [64], freeze-drying [65] and cryogenic freezing with liquid nitrogen [59; 66].…”

“…An example of the use of HPLC-ICP-MS, shown in Table 1 is in the determination of arsenic species in lichens and plants near a decomissioned arsenic smelter site in Austria [65], whilst sequential extractions were used to separate As species in lichens to assess As air pollution in another study [77] ( Table 1). Extractions were performed on powdered lichens using water, CaCl 2 and H 3 PO 4 respectivelyIt was concluded that biotransformation of As may have occured, where the lichens were thought to methylate the As species as a protective measure.…”

The contents of risk elements, arsenic speciation, and possible interactions of elements and betalains in beetroot (Beta vulgaris, L.) growing in contaminated soil

“…Therefore, the abundance and distribution of arsenic compounds within red beet plants did not differ significantly from the behavior of arsenic compounds in other plant species and the results were expectable. Comparable results have been presented by other authors within different plant species [16,19,20,44].…”

“…Transformation and translocation of arsenic compounds among plant tissues is strongly dependent on plant species and/or soil characteristics [17]. The occurrence of individual arsenic compounds in higher plants and their distribution into different plant tissues are strongly dependent on plant species [18,19]. As(III), As(V), DMA, MA, trimethylarsine oxide, the tetramethylarsonium ion, and one arsenoribose were identified in green plant species grown at arsenic contaminated sites; the compounds and their concentrations differ with plant species [19,20].…”

“…The occurrence of individual arsenic compounds in higher plants and their distribution into different plant tissues are strongly dependent on plant species [18,19]. As(III), As(V), DMA, MA, trimethylarsine oxide, the tetramethylarsonium ion, and one arsenoribose were identified in green plant species grown at arsenic contaminated sites; the compounds and their concentrations differ with plant species [19,20]. The presence of arsenic phytochelatin complexes in Holcus lanatus, Pteris cretica [21], Cicer arietinum [22], and Helianthus annuus [23] was discussed as mechanism of plant tolerance to enhanced arsenic content.…”