Fluorine contamination, mobility, and risks in soils at a phosphate-gypsum waste landfill: a new analytical method and comparison with previous methods.

This study used a new X-ray fluorescence (XRF)-based analytical method with better precision and sensitivity to evaluate the fluorine concentrations in soil. It was hypothesized that the XRF method with a pellet-synthesizing procedure may effectively analyze the fluorine concentrations in soil with ease and reliability. The total fluorine concentrations determined using XRF were compared with those determined using three different types of analytical protocols-incineration/distillation, alkaline fusion, and aqua regia extraction procedures.

Adsorption Characteristics of Dimethylated Arsenicals on Iron Oxide-Modified Rice Husk Biochar.

In this study, the adsorption characteristics of dimethylated arsenicals to rice husk biochar (BC) and Fe/biochar composite (FeBC) were assessed through isothermal adsorption experiments and X-ray absorption spectroscopy analysis. The maximal adsorption capacities (q) of inorganic arsenate, calculated using the Langmuir isotherm equation, were 1.28 and 6.

New insights into surface behavior of dimethylated arsenicals on montmorillonite using X-ray absorption spectroscopy.

Although recent studies have revealed the occurrence of dimethylated arsenicals, little is known about their behavior in environment. This study investigates the adsorption behavior of dimethylarsinic acid (DMA), dimethyldithioarsinic acid (DMDTA), and dimethylmonothioarsinic acid (DMMTA) on montmorillonite. Complicated transformations among arsenicals under normal environmental conditions were also considered.

Dimethylmonothioarsinic acid and dimethyldithioarsinic acid in the environment: Sorption characteristics on 2-line ferrihydrite and acute toxicity to Daphnia magna.

Dimethylmonothioarsinic acid (DMMTA(V)) and dimethyldithioarsinic acid (DMDTA(V)), which are commonly found in landfill leachate and pore water of rice paddy soil, have attracted considerable attention for their high toxicity. This study aims to evaluate the behavior and potential risks of DMMTA(V) and DMDTA(V) in the environment by conducting an equilibrium sorption test using 2-line ferrihydrite and acute toxicity (immobilization) test using Daphnia magna. The overall maximum sorption capacity (q) derived by the Langmuir isotherm model showed an increase in the order of inorganic arsenate (As(V)) > dimethylarsinic acid (DMA(V)) > DMMTA(V) > DMDTA(V), which was likely due to steric hindrance due to the presence of methyl and thiol groups.

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation.

Dimethylated thioarsenicals such as dimethylmonothioarsinic acid (DMMTA) and dimethyldithioarsinic acid (DMDTA), which are produced by the metabolic pathway of dimethylarsinic acid (DMA) thiolation, have been recently found in the environment as well as human organs. DMMTA and DMDTA can be quantified to determine the ecological effects of dimethylated thioarsenicals and their stability in environmental media. The synthesis method for these compounds is unstandardized, making replicating previous studies challenging.

Kinetics of Dimethylated Thioarsenicals and the Formation of Highly Toxic Dimethylmonothioarsinic Acid in Environment.

Dimethylmonothioarsinic acid (DMMTA) is a highly toxic, thiolated analogue of dimethylarsinic acid (DMA). In comparison, a further thiolated analogue, dimethyldithioarsinic acid (DMDTA), and DMA both exhibit lower toxicity. To understand the environmental conditions responsible for forming DMMTA, the kinetics of DMA thiolation are examined.

Effectiveness of activated carbon disk for the analysis of iodine in water samples using wavelength dispersive X-ray fluorescence spectrometry.

A novel approach using wavelength dispersive X-ray fluorescence (WDXRF) spectrometry combined with an activated carbon (AC) disk was developed for the determination of total iodine concentrations in water samples. Dissolved iodine species (i.e.

Formation of dimethyldithioarsinic acid in a simulated landfill leachate in relation to hydrosulfide concentration.

Dimethyldithioarsinic acid (DMDTA(V)), present in such intense sources as municipal landfill leachate, has drawn a great deal of attention due to its abundant occurrence and different aspect of toxicity. The hydrosulfide (HS(-)) concentration in leachate was studied as a major variable affecting the formation of DMDTA(V). To this end, the HPLC-ICPMS system equipped with the reversed-phase C18 column was used to determine DMDTA(V).

Fluorine distribution in soil in the vicinity of an accidental spillage of hydrofluoric acid in Korea.

This study assessed the status of fluorine (F) in soil in the vicinity of a spillage of anhydrous hydrofluoric acid in Korea. Gaseous hydrogen fluoride dispersed was suspected to have contaminated the surrounding soil environment. Total and water soluble F concentrations in soil within a 1 km radius of the spillage were determined.

A simplified analysis of dimethylarsinic acid by wavelength dispersive X-ray fluorescence spectrometry combined with a strong cation exchange disk.

Dimethylarsinic acid (DMA(V)) was pre-concentrated from water samples using a strong cation exchange (SCX) disk functionalized with sulfonic groups, before being analyzed by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). The adsorption of DMA(V) occurred preferentially on the surface of the SCX disk, regardless of pH levels, probably due to interactions with the sulfonic functional groups. However, no other arsenic species, such as arsenate (iAs(V)), arsenite (iAs(III)), and monomethylarsonic acid (MMA(V)), were retained.

A simple approach for measuring emission patterns of vapor phase mercury under temperature-controlled conditions from soil.

In an effort to study the possible effects of climate change on the behavior of atmospheric mercury (Hg), we built a temperature-controlled microchamber system to measure its emission from top soils. To this end, mercury vapour emission rates were investigated in the laboratory using top soil samples collected from an urban area. The emissions of Hg, when measured as a function of soil temperature (from ambient levels up to 70°C at increments of 10°C), showed a positive correlation with rising temperature.

Effect of incineration on the removal of key offensive odorants released from a landfill leachate treatment station (LLTS).

As a basic means to control odorants released from a landfill leachate treatment station (LLTS), effluents venting from this station were treated via incineration with methane rich landfill gas (at 750°C). A list of the key offensive odorants covering 22 chemicals was measured by collecting those gas samples both before and after the treatment. Upon incineration, the concentration levels of most odorants decreased drastically below threshold levels.