Fate of fenthion in salt‐marsh environments: II. Transport and biodegradation in microcosms

O'Neill, Ellen J.; Cripe, C. R.; Mueller, Leonard H.; Connolly, John P.; Pritchard, P. H.

doi:10.1002/etc.5620080902

Cited by 11 publications

(1 citation statement)

References 19 publications

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“…Fenthion is easily degraded to fenthion-sulfoxide in soil under aerobic conditions, 37) and the DT 50 of fenthion is 1.5 days in a water-sediment system. 40,41) The half life of fenthion-sulfoxide in water and soil under aerobic conditions (DT 50 ϭ 12.7-16.0 days) 42) is longer than that of the parent compound. For this reason, fenthion-sulfoxide was rapidly formed in paddy fields and was the main compound detected in river water.…”

Section: Insecticide Metabolitesmentioning

confidence: 99%

Behavior of paddy pesticides and major metabolites in the Sakura River, Ibaraki, Japan

et al. 2010

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Thirty-nine paddy pesticides and 11 of their metabolites were monitored in the Sakura River during the rice cultivation season in 2007 and 2008. Pesticide concentrations in the river water depended on the timing of pesticide application. Herbicides that were shipped to Ibaraki Prefecture in large amounts or had high water solubility, a low soil adsorption constant value, or large usage rates were detected at high peak concentrations. The concentrations of nursery-box-applied fungicides and insecticides peaked immediately after transplanting. The concentrations of pesticide metabolites, such as bromobutide-desbromo, cafenstrol-descarbamoyl, clomeprop-propionic acid, carbofuran, and fenthion-sulfoxide depended on the degradation rates and metabolic pathways of the parent compounds and on the stability of the metabolites in water and soil. Clomeprop-propionic acid, carbofuran, and fenthion-sulfoxide, which were formed from rapidly degradable pesticides, were detected at much higher peak concentrations than the parent compounds. © Pesticide Science Society of Japan Keywords: paddy pesticide, application timing, river water, physicochemical property, metabolic pathway, environmental fate. Original Articlefield area is under rice cultivation. After soil puddling and land leveling in late April, rice seedlings are transplanted in early May. Intermittent irrigation starts in mid-June and continues throughout the growing period, except during the midsummer drainage period from late June to mid-July. Generally, heading occurs from late July to early August, and harvest starts in early September, after drainage of the paddy water in late August. 15)Early-mid-season herbicides are applied within 2 weeks after transplanting (early to mid-May), and mid-season herbicides are applied 2-3 weeks after transplanting (late May to early June). Depending on the emergence of weeds, a lateseason herbicide might be used in June.16) Fungicides and insecticides are used on rice seedlings in nursery boxes before transplanting and for direct application to paddy fields before heading or harvest. Recently, nursery-box application has become increasing popular in the Sakura River basin. Aerial spraying of paddy pesticides was not conducted in the basin in 2007 and 2008 (Japan Agricultural Aviation Association: private communication; unpublished data). Analyzed compoundsTwenty-nine herbicides, 2 fungicides, and 8 insecticides were selected for analysis (Table 1), in consideration of the amounts of paddy pesticides shipped to Ibaraki Prefecture recently. We selected 11 metabolites of the herbicides and insecticides in accord with previous studies 11,14,17,18) as a reference. All analytical standards were purchased from Wako Pure Chemicals Industries (Japan), Hayashi Pure Chemicals Industries (Japan), or Kanto Chemicals (Japan). Sample collection and analysisThe sampling site (Kimijima Bridge) is located midway along the course of the Sakura River (Fig. 1). Water samples (approximately 3000 ml per sample) were collected once a week on Monday fr...

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Section: Insecticide Metabolitesmentioning

confidence: 99%

Behavior of paddy pesticides and major metabolites in the Sakura River, Ibaraki, Japan

et al. 2010

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Fate of fenthion in salt‐marsh environments: I. Factors affecting biotic and abiotic degradation rates in water and sediment

Cripe

O'Neil

Woods

et al. 1989

Enviro Toxic and Chemistry

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Fenthion (Baytex), an organophosphate insecticide, is frequently applied to salt‐marsh environments to control mosquitoes. Shake‐flask tests were used to study rates of abiotic and biotic degradation of fenthion and the environmental parameters that affect these rates. Water or water‐sediment (500 mg dry weight/L) slurries from salt marshes located along the Northwest Florida Gulf Coast were used. Flasks contained 200 μg fenthion/L, and degradation rates were determined by following decrease of fenthion over time. Hydrolysis and biodegradation in water were relatively insignificant fate processes; fenthion disappeared from flasks containing water, formalin‐sterilized water, or formalin‐sterilized sediment very slowly (half‐life ≥ 2 weeks). The presence of nonsterile sediment resulted in a rapid exponential disappearance of fenthion (half‐life ≥ 3.8 d). Biodegradation was assumed since sterile sediment systems showed a much slower decrease of fenthion, and the production of polar compounds (hexane‐unextractable) from radiolabeled fenthion was greater in the presence of sediment than sterilized sediment. The effect of environmental pH levels (5.0–7.0) on degradation was insignificant. No biotic degradation occurred at low oxygen concentration. An 8°C decrease in incubation temperature decreased the rate of sediment biodegradation 2.5‐fold. Light caused a slight, but significant, increase in the biotic and abiotic degradation rates of fenthion in water. A two‐fold variation in sediment‐mediated degradation was noted among sediment samples from three stations within one field site. Inclusion of whole marsh plants or plant parts increased the disappearance rate of fenthion in test systems.

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Modeling the vertical distribution of carbendazim in sediments

Koelmans

Hubert

Koopman

et al. 2000

Enviro Toxic and Chemistry

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Abstract-The sorption, fate, and vertical distribution of the fungicide Derosal with active ingredient carbendazim in sediments were investigated in indoor freshwater microcosms. Carbendazim penetration in the sediment was measured as a function of time and depth. Freundlich sorption parameters were determined by batchwise equilibration of carbendazim in a sediment suspension. Freundlich parameters were K f ϭ 258 g (1Ϫn) L n /kg and n ϭ 0.78. Analysis of different layers of sediment cores showed a slow penetration of carbendazim in the first 6 cm of the sediment in 60 d. The penetration was successfully simulated with a multilayer model accounting for sorption to organic matter (using the measured isotherm), molecular diffusion, biodegradation, and bioturbation. The calibrated model was most sensitive to the parameters for molecular diffusion and sorption in the sediment. Bioturbation did not affect the carbendazim profiles because of carbendazim toxicity for bioturbators. So there was a direct feedback between carbendazim toxicity and fate. The calibrated model was validated using a dataset obtained from another freshwater microcosm.

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Fate of fenthion in salt‐marsh environments: II. Transport and biodegradation in microcosms

Cited by 11 publications

References 19 publications

Behavior of paddy pesticides and major metabolites in the Sakura River, Ibaraki, Japan

Behavior of paddy pesticides and major metabolites in the Sakura River, Ibaraki, Japan

Fate of fenthion in salt‐marsh environments: I. Factors affecting biotic and abiotic degradation rates in water and sediment

Modeling the vertical distribution of carbendazim in sediments

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