Occurrence, Seasonal Variation, and Size Resolved Distribution of Arsenic Species in Atmospheric Particulate Matter in an Urban Area in Southeastern Austria.

Stefan Tanda,Roman Ličbinský,Walter Goessler,Katharina Gingl,Jitka Hegrová

doi:10.1021/acs.est.9b07707

Stefan Tanda, Roman Ličbinský + Show 3 more

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https://doi.org/10.1021/acs.est.9b07707

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Abstract

Extensive information is available on total arsenic in particulate matter (PM), but little is known about the relative contribution of each individual species. Recent studies often focus on inorganic arsenic as arsenite and arsenate, neglecting the organoarsenicals, i.e., methylarsine, dimethylarsine, and trimethylarsine or the corresponding oxidized forms methylarsonate, dimethylarsinate, and trimethylarsine oxide, although they were already first detected in PM in the mid-1970s. This work presents results from more than 300 daily PM10 and further size-resolved atmospheric PM samples in the size range from 15 nm to 10 μm collected in an urban environment in Austria during the course of a year. An ion-exchange-HPLC (with anion and cation exchange columns) and an ICPMS/MS system were used to study the seasonal variations of total arsenic and all species known to exist in PM. Inorganic arsenic was present in significant amounts in all samples with highest concentrations during winter, but also all organoarsenicals were detected throughout the year. We show that their contribution cannot be ignored, as particles smaller than <1 μm can contain up to 35% of the water+H2O2 extractable arsenic as methylated species, but only dimethylarsinate showed a clear seasonal trend throughout the year.

Highlights

Arsenic (As) is a metalloid distributed ubiquitously in the earth’s crust (54th in abundance),[1] found in water, air, soils, and even living organisms
This is despite the fact that Johnson and Braman, who studied alkyl- and inorganic As in air samples from a variety of urban, suburban, and rural areas, found approximately 20% of the total As (1.7 ng As m−3) to be present in the alkyl-arsenic form back in 1975.7 Mukai et al described the seasonality of organoarsenicals in airborne particulate matter, with changes in temperature for two sites in Japan in the mid-1980s
DMA and trimethylarsine oxide (TMAO) were thought to have been formed via biomethylation, whereas trace amounts of MA detected in summer were attributed to contamination by methylarsonate containing pesticides used nearby

Summary

Introduction

Arsenic (As) is a metalloid distributed ubiquitously in the earth’s crust (54th in abundance),[1] found in water, air, soils, and even living organisms. The keen interest to study the element and its containing compounds is based on its complex toxicity.[2,3] air represents an important route of dispersion allowing global transport,[4] little is known about the behavior of arsenic containing species present in the atmosphere, especially regarding methylated As. In air, arsenic exists in the gaseous and the particulate matter phase, but it is predominantly absorbed on particles as a mixture of inorganic arsenic as arsenite (AsIII) and arsenate (AsV) and methylated organoarsenicals, namely methylarsonate (MA), dimethylarsinate (DMA), and trimethylarsine oxide (TMAO).[5]. DMA and TMAO were thought to have been formed via biomethylation, whereas trace amounts of MA detected in summer were attributed to contamination by methylarsonate containing pesticides used nearby. These results already provide a strong support for a significant contribution of biomethylation to the atmospheric arsenic cycle

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