Earthworms as agents for arsenic transport and transformation in roxarsone-impacted soil mesocosms: A µXANES and modeling study

Organoarsenicals in poultry litter: Detection, fate, and toxicity

“…Indeed, inhibition data was also associated with mineralization of HAPA to the more toxic, As(III) (Sierra-Alvarez et al, 2010). Earthworms convert roxarsone to methylated arsenic (Covey et al, 2010), and accumulate arsenic in the form of arsenic glutathione complexes. Combined fate and toxicology studies are needed to provide important insight into how the transition of arsenic from organic to inorganic forms and the corresponding toxicity throughout these reactions.…”

“…Organoarsenicals have been detected in solid media, such as animal litter (Jackson and Bertsch, 2001;Garbarino et al, 2003;Rosal et al, 2005;Yao et al, 2009a;D'Angelo et al, 2012), agricultural soils (Woolson, 1975;Covey et al, 2010;Liu et al, 2013;Yao et al, 2013b); liquids like agricultural runoff , groundwater (Daus et al, 2008;Hempel et al, 2009), and urine/blood of animals (Overby and Fredrickson, 1965;Xie et al, 2006); and biological tissues (Croteau et al, 1994;Dean et al, 1994;Schmidt et al, 2008;Monasterio et al, 2011;Conklin et al, 2012). Extraction of organoarsenicals from environment samples must ensure high recovery without compromising the arsenic speciation chemistry (i.e., organic vs. inorganic).…”

“…Covey et al (2010) studied the role of earthworms and burrowers in degrading roxarsone in soils. In that study, roxarsone was converted to methylated and inorganic forms within 30 days.…”

Transport of gadolinium- and arsenic-based pharmaceuticals in saturated soil under various redox conditions

“…Literature mentions that between 36 and 88% of the total arsenic in the litter of chickens fed with ROX is unaltered ROX. The remaining As is mostly inorganic arsenate (As(V)), with minor traces of dimethylarsenic acid (DMA(V)) and unidentified As species originating from metabolism of ROX (Covey et al, 2010).…”

“…ROX is degraded rapidly during composting of litter, during storage and land application of litter, and in leachates from fields. Degradation products include inorganic As(V) and As(III), known to be the most toxic arsenic compounds, as well as a variety of organic arsenicals (O'Connor et al, 2005;Komorowicz and Baralkiewicz, 2011), depending on pH, redox conditions (Covey et al, 2010), interaction with minerals, and organic matter in soils and aquifer sediments (Brown et al, 2005). There are three main biotransformation processes of arsenic in the environment: redox transformation between As(V) and As(III), reduction and methylation of arsenic, and biosynthesis of organoarsenic compounds (Yaron et al, 2012).…”