Sea Level Rise Induced Arsenic Release from Historically Contaminated Coastal Soils

• Published in: Environmental science & technology 2017-06, Vol.51 (11), p.5913-5922
• Main Authors: LeMonte, Joshua J, Stuckey, Jason W, Sanchez, Joshua Z, Tappero, Ryan, Rinklebe, Jörg, Sparks, Donald L
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Anthropogenic factors; Arsenic; arsenic, geochemistry; Biogeochemistry; Chemical analysis; Climate Change; Coasts; Contaminants; Dissolution; Historical account; Human influences; Hydrology; MATERIALS SCIENCE; Natural waters; Oxidation; Oxides; Reactors; redox; Rivers; Sea level; Sea level rise; Seawater; Soil; soil chemistry; Soil conditions; Soil contamination; Soil gradation; Soil Pollutants; Soil pollution; Soils; Speciation; Spectroscopy; Spectrum analysis; Water analysis; X-Ray Absorption Spectroscopy; XANES
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.6b06152

Climate change-induced perturbations in the hydrologic regime are expected to impact biogeochemical processes, including contaminant mobility and cycling. Elevated levels of geogenic and anthropogenic arsenic are found along many coasts around the world, most notably in south and southeast Asia but also in the United States, particularly along the Mid-Atlantic coast. The mechanism by and the extent to which arsenic may be released in contaminated coastal soils due to sea level rise are unknown. Here we show a series of data from a coastal arsenic-contaminated soil exposed to sea and river waters in biogeochemical microcosm reactors across field-validated redox conditions. We find that reducing conditions lead to arsenic release from historically contaminated coastal soils through reductive dissolution of arsenic-bearing mineral oxides in both sea and river water inundations, with less arsenic release from seawater scenarios than river water due to inhibition of oxide dissolution. For the first time, we systematically display gradation of solid phase soil-arsenic speciation across defined redox windows from reducing to oxidizing conditions in natural waters by combining biogeochemical microcosm experiments and X-ray absorption spectroscopy. Our results demonstrate the threat of sea level rise stands to impact arsenic release from contaminated coastal soils by changing redox conditions.