Aqueous photochemistry of pesticides triadimefon and triadimenol

Silva, J.P. Da; Ferreira, L. F. Vieira; Silva, Abílio M. Da

doi:10.1016/s1010-6030(02)00328-3

Cited by 28 publications

(20 citation statements)

References 13 publications

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“…From the figure, it was found that the photodegradation process follows a pseudo-first-order kinetic equation. This result was in agreement with that of most pesticide photolysis (Da Silva et al 2003). The rate constants of acetamiprid photolysis under different conditions were determined, and listed in Table 1.…”

Section: Resultssupporting

confidence: 86%

Kinetics of Acetamiprid Photolysis in Solution

Xie

Liu

Sun

et al. 2008

Bull Environ Contam Toxicol

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Photolysis of acetamiprid was investigated in detail under different reaction conditions. The photolysis of acetamiprid in solution followed pseudo-first-order kinetics under the experimental conditions. Acetamiprid kept stable under irradiation of high-pressure xenon lamp but degraded relatively fast when exposure to medium-pressure mercury lamp irradiation. The experimental results indicated that the degradation rate of acetamiprid in acetone was the largest among the used media and acetamiprid was more stable in basic media. The addition of oxygen, increase of light intensity and temperature will enhance the photolysis.

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Section: Resultssupporting

confidence: 86%

Kinetics of Acetamiprid Photolysis in Solution

Xie

Liu

Sun

et al. 2008

Bull Environ Contam Toxicol

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“…The quantum yield of a photochemical reaction depends on maximum light absorption of compounds undergoing the process, wavelength of the radiation, the properties of the solvent used [7] and the pH [8][9][10] of the solution. Boule et al [9] point out the impact of chlorophenol speciation -dissociated or undissociated -on the quantum yield for photolysis of monochlorophenols upon 254 nm irradiation.…”

Section: Quantum Yield Of the Photolysismentioning

confidence: 99%

Photo-degradation of chlorophenols in the aqueous solution

Czaplicka

2006

Journal of Hazardous Materials

251

152

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“…Like many pesticides, these chemicals enter surface waters through direct application techniques (e.g. spray drift, disposal of livestock treatment liquors etc), by diffusive leaching from soil and vegetation (Da Silva et al 2003) as well as through wet and dry deposition processes following transport in the atmosphere (e.g. Hageman et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Effects of Dissolved Water Constituents on the Photodegradation of Fenitrothion and Diazinon

Ukpebor

Halsall

2011

Water Air Soil Pollut

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The photochemical degradation of two widely used organophosphorothioate insecticides, fenitrothion and diazinon, was investigated in aqueous solutions containing three separate dissolved constituents commonly found in natural waters (NO 3 − , CO 3 2− and dissolved organic matter (DOC)). The effect of these constituents on pesticide photodegradation was compared to degradation in "constituent-free" pure water. Solutions were irradiated in an Atlas solar simulator fitted with a UV-filtered Xenon arc lamp with light irradiances (500 W m −2 ) measured using a spectral radiometer to allow derivation of quantum yields of degradation. Fenitrothion absorbs light within the solar UV range (λ, 295-400 nm) and underwent direct photolysis in pure water whereas diazinon (λ max ∼250 nm) showed no observable loss over the experimental period. However, photodegradation conforming to pseudo-first-order kinetics was observed for both chemicals in the presence of the dissolved constituents (at concentrations typically observed in natural waters), with the rates of photodecay observed in the order of NO 3 − >CO 3 2− ≅DOC, with the highest rates observed in the 3 mM NO 3 − solutions (k Fen = 0.155±0.041 h −1 ; k Dia =0.084±0.0007 h −1 ). For diazinon this rate was comparable to fenitrothion photolysis in pure water (k fen 0.072±0.0078 h −1 ), highlighting the importance of NO 3 − on a non-photolabile pesticide, with indirect photodegradation probably attributable to the light-induced release of aqueous hydroxyl radicals ( · OH) from NO 3 − . Suwannee river fulvic acid (serving as DOC) did not statistically affect the rate of photodecay for fenitrothion relative to its photolysis in MilliQ water, although measured rates in DOC solutions were slightly lower. However, measurable rates of photodecay were apparent for diazinon in the DOC solutions, indicating that fulvic acid, possibly in the form of "excited" triplet-state-DOC plays a role in diazinon transformation. Hydrolysis was not apparent for fenitrothion (in buffered solutions of pH 5-9) but was notable for diazinon at the lower pHs of 5 and 3 (k Dia-hyd 0.3414 h −1 at pH 3 and 0.228 h −1 at pH 5), resulting in the formation of the degradate, 2-isopropyl-6-methyl-4-pyrimidinol. This work highlights the importance of dissolved constituents on abiotic photodegradation of pesticides and it is recommended that these constituents be incorporated into laboratory-based fate-testing regimes.

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Aqueous photochemistry of pesticides triadimefon and triadimenol

Cited by 28 publications

References 13 publications

Kinetics of Acetamiprid Photolysis in Solution

Kinetics of Acetamiprid Photolysis in Solution

Photo-degradation of chlorophenols in the aqueous solution

Effects of Dissolved Water Constituents on the Photodegradation of Fenitrothion and Diazinon

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