Arsenic Speciation of Contaminated Soils/Solid Wastes and Relative Oral Bioavailability in Swine and Mice

Abstract

Arsenic (As) is one of the most widespread, toxic elements in the environment, and human activities have resulted in a large number of contaminated areas. However abundant, the potential of As toxicity from exposure to contaminated soils is limited to the fraction that will dissolve in the gastrointestinal system and be absorbed into systemic circulation or bioavailable species. In part, the release of As from contaminated soil to gastrointestinal fluid depends on the form of solid phase As, also termed "As speciation". In this study, 27 As-contaminated soils and solid wastes were analyzed using X-ray absorption spectroscopy (XAS) and results were compared to in vivo bioavailability values determined using the adult mouse and juvenile swine bioassays. Arsenic bioavailability was lowest for soils that contained large amounts of arsenopyrite and highest for materials that contained large amounts of ferric arsenates. Soil and solid waste type and properties rather than the contamination source had the greatest influence on As speciation. Principal component analysis determined that As(V) adsorbed and ferric arsenates were the dominant species that control As speciation in the selected materials. Multiple linear regression (MLR) was used to determine the ability of As speciation to predict bioavailability. Arsenic speciation was predictive of 27% and 16% of Relative Bioavailable (RBA) As determined using the juvenile swine and adult mouse models, respectively. Arsenic speciation can provide a conservative estimate of RBA As using MLR for the juvenile swine and adult mouse bioassays at 55% and 53%, respectively.

Nutrients and antinutrient constituents of Amaranthus caudatus L. Cultivated on different soils

“…Texture modulation affects the concentration of chemical compounds available in the soil ( Biswas et al, 2018 ). These chemicals find their way up in plants through adsorption or direct absorption from the soil solution.…”

Responses of Soil Fungal Communities to Lime Application in Wheat Fields in the Pacific Northwest

“…Continuous use of ammonium-based nitrogen fertilizers and long-term continuous crop growth has caused soil pH to drop below optimum levels for crop production ( Schroder et al, 2011 ; Jones et al, 2019 ). With soil acidification, pH values below 5.5 increase the solubility and concentration of aluminum (Al 3+ ) and manganese (Mn 2+ ) in soil which can cause phytotoxicity and reduced crop yields ( Kidd and Proctor, 2001 ; Schroder et al, 2011 ; Schroeder and Pumphrey , 2013 ; Lewis et al, 2018 ). In addition, lower pH also reduces water uptake and soil nutrient availability for plants ( Kemmitt et al, 2006 ).…”

“…In addition, lower pH also reduces water uptake and soil nutrient availability for plants ( Kemmitt et al, 2006 ). To alleviate the harmful effects of low soil pH on crops, lime can be applied to buffer soil acidification, minimize toxic effects of Al 3+ and Mn 2+ , and increase soil fertility and plant ecosystem health ( Holland et al, 2018 ; Lewis et al, 2018 ; Schroeder et al, 2018 ).…”

“…Soil pH is considered to be one of the most important soil health indicators ( Kemmitt et al, 2006 ; Rousk et al, 2009 ), strongly influences microbial communities ( Thompson et al, 2017 ; Jin and Kirk, 2018 ) and impacts the metabolic activity of the soil microbiome ( Leprince and Quiquampoix, 1996 ; Kotsyurbenko et al, 2004 ; Ye et al, 2012 ). Lime application in acidic soil increases soil pH, especially in the soil surface ( Lewis et al, 2018 ; Yin et al, submitted manuscript). Numerous studies have examined the impacts of lime on soil microbes and revealed that lime application changed soil microbial composition and regulated their activities and functions ( Narendrula-Kotha and Nkongolo, 2017 ; Lewis et al, 2018 ; Schroeder et al, 2018 ; Pang et al, 2019 ).…”

“…Lime application in acidic soil increases soil pH, especially in the soil surface ( Lewis et al, 2018 ; Yin et al, submitted manuscript). Numerous studies have examined the impacts of lime on soil microbes and revealed that lime application changed soil microbial composition and regulated their activities and functions ( Narendrula-Kotha and Nkongolo, 2017 ; Lewis et al, 2018 ; Schroeder et al, 2018 ; Pang et al, 2019 ). Our recent study found that liming has a small effect on soil bacterial communities and the impacts were especially prominent in the surface soil, compared with location and soil depth (Yin et al, submitted manuscript).…”