Abstract:
Thiolated arsenic compounds are the sulfur analogous substructures of oxo-arsenicals as the arsinoyl (As=O) is
substituted by an arsinothioyl (As=S) group. Relatively brief history of thioarsenic research, mostly in the
current decade has endeavored to understand their consequences in the natural environment. However,
thioarsenic related aspects have by far not attached much research concern on global scale compared to other
arsenic species. This review attempts to provide a critical overview for the first time on formation mechanisms of
thioarsenicals, their chemistry, speciation and analytical methodologies in order to provide a rational assessment
of what is new, what is current, what needs to be known or what should be done in future research. Thioarsenic
compounds play a vital role in determining the biogeochemistry of arsenic in sulfidic environments under reducing
conditions. Thioarsenic species are widely immobilized by naturally occurring processes such as the
adsorption on iron (oxyhydr)oxides and precipitation on iron sulfide minerals. Accurate measurement of
thioarsenic species is a challenging task due to their instability upon pH, temperature, redox potential, and
concentrations of oxygen, sulfur and iron. Assessment of direct and indirect effects of toxic thioarsenic species on
global population those who frequently get exposed to high levels of arsenic is an urgent necessity.
Dimethylmonothioarsinic acid (DMMTAV) is the most cytotoxic arsenic metabolite having similar toxicological
effects as dimethylarsinous acid (DMAIII) in human and animal tissues. The formation and chemical analysis of
thioarsenicals in soil and sediments are highly unknown. Therefore, future research needs to be more inclined
towards in determining the molecular structure of unknown thioarsenic complexes in various environmental
suites. Contemporary approaches hyphenated to existing technologies would pave the way to overcome critical
challenges of thioarsenic speciation such as standards synthesis, structural determination, quantification and
sample preservation in future research.
