Radiolysis studies on the destruction of microcystin-LR in aqueous solution by hydroxyl radicals.

In this study, steady-state and time-resolved radiolysis methods were used to determine the primary reaction pathways and kinetic parameters for the reactions of hydroxyl radical with microcystin-LR (MC-LR). The fundamental kinetic data is critical for the accurate evaluation of hydroxyl-radical based technologies for the destruction of this problematic class of cyanotoxins. The bimolecular rate constant for the reaction of hydroxyl radical with MC-LR is 2.

Adsorption and photocatalyzed oxidation of methylated arsenic species in TiO2 suspensions.

Monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) are used as herbicides in the agriculture industry. We have demonstrated that MMA and DMA are readily degraded upon TiO2 photocatalysis. DMA is oxidized to MMA as the primary oxidation product, which is subsequently oxidized to inorganic arsenate, As(V).

Hydroxyl radical mediated degradation of phenylarsonic acid.

Phenyl-substituted arsonic acids have been widely used as feed additives in the poultry industry. While very few studies have been reported on the environmental impact of these compounds, they have been introduced into the environment through land application of poultry litter in large quantities (about 10(6) kg/year). Phenylarsonic acid (PA) was used as a model for problematic arsonic acids.

Mechanistic evaluation of arsenite oxidation in TiO2 assisted photocatalysis.

We report herein a detailed assessment of the roles of O2, H2O2, *OH, and O2-* in the TiO2 assisted photocatalytic oxidation (PCO) of arsenite. Although both arsenite, As(III), and arsenate, As(V), adsorb extensively onto the surface of TiO2, past studies relied primarily on the analysis of the arsenic species in solution, neglecting those adsorbed onto the surface of TiO2. We used extraction and analyses of the arsenic species adsorbed onto the surface of the TiO2 to illustrate that the oxidation of As(III) to As(V) occurs in an adsorbed state during TiO2 PCO.

Application of toxicity identification evaluation procedures to an effluent from a nitrogenous fertilizer plant in China.

The integrated method combining chemistry and toxicology, toxicity identification evaluation (TIE), was conducted to identify key toxicants in an effluent from a nitrogen fertilizer plant in China. Toxicity characterization, phase I of TIE, revealed that the suspected toxicant in the effluent was an anion that could be changed into a volatile acid. The results of toxicity identification and confirmation procedures indicated potassium cyanide to be the primary toxicant in the effluent.