Antimony (Sb) is a naturally occurring element, ranging from 0.3 – 8.4 mg kg^-1 in soils. The US-EPA and EU consider Sb a priority pollutant of interest, potentially carcinogenic, and volatile stibines are known genotoxins. Sb contaminated sites, such as mining and smelting and shooting range sites are potential point sources of volatile Sb into the environment.

Volatile Sb, stibine (SbH₃), monomethylstibine (MMSb), dimethylstibine (DMSb), and trimethylstibine (TMSb), can be produced at ambient temperatures under aerobic and anaerobic conditions and represent an understudied portion of the biogeochemical cycle of Sb. Few studies have investigated volatile Sb production in natural media. The production and formation of volatile Sb in the soil environment is poorly understood due to the lack of an easy-to-use method for field and lab quantification.

We validated a method for trapping hydrides of Sb (SbH₃ and TMSb) using activated carbon sorbent material (ACSM). Volatile species of antimony were synthesized by hydride generation (HG) using standard solutions made from Sb(III) and trimethylantimony and trapped on ACSM. Our digestion method is validated for total Sb and recoveries of digested traps for HG of SbH₃ were 89.58 ± 6.75 % (n = 3) and TMSb were 92.34 ± 3.94 % (n = 4). This method was used to capture total volatile Sb emanating from manure-amended (5%) flooded shooting range soils (Laupen, Switzerland) during an incubation period of 36 days. Our results show volatile Sb is produced from contaminated shooting range soils.

We observed the in-situ production of volatile Sb from two rice paddy fields in the vicinity of the worlds largest Sb deposit (Xikuangshan mine, Lengshuijiang, China) using our newly validated trapping method for total volatile Sb. Our results show that volatile Sb is produced at low (< 80 mg kg^-1 Sb) and high (< 400 mg kg^-1 Sb) Sb contaminated sites in rice paddy fields. Up to 160 ng of Sb was trapped on the ACSM traps after t = 4 days at the high Sb site. These results equate up to 390.65 mg ha^-1 y^-1 of volatile Sb being produced from high Sb paddy fields. The relationship of Sb- volatilization with other parameters (Sb and multielement concentrations in porewaters and soils, DOC, anions (e.g., NO₃^2-, NO₂^-, SO₄^2-), pH and redox potential) will be discussed.

We developed an easy and field-deployable method to capture volatile Sb produced from incubation and field experiments. Our results are the first to indicate volatile Sb is produced from flooded contaminated shooting range soils and paddy field sites. As these sites represent large point sources of Sb and have favorable conditions for bio- methylation and -volatilization processes, they could be large contributors of toxic stibines to the environment and influence the biogeochemical cycling of Sb.