The Environmental Fate of Three Dichlorophenyl Nitrophenyl Ether Herbicides in a Rice Paddy Model Ecosystem

Lee, An-Horng; Lu, Po-Yung; Metcalf, Robert L.; Hsu, Err-Lieh

doi:10.2134/jeq1976.00472425000500040035x

Cited by 19 publications

(10 citation statements)

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“…Glutathione conjugation was observed in the metabolism of isoproturon (118), an aquatic macrophyte, whose metabolites were identified by LC-MS (Pietsch et al 2006). In addition to the usual cleavage of C-O and C-N bonds in esters and amides, a unique cleavage is known for the ether linkage in diphenyl ethers (Cai et al 2007(Cai et al , 2008Lee et al 1976), the S-N bond of bentazone (137) (Booth et al 1973), and the Sn-C bond of tributyltin (16) (Lee et al 1989;Maguire et al 1984).…”

Section: Other Pesticidesmentioning

confidence: 99%

“…A radiolabeled pesticide may be applied to any compartment of an ecosystem (such as water or bottom sediment) to simulate spray drift or a runoff event, etc. Aquatic model ecosystems can be classified as being terrestrial-aquatic (Metcalf et al 1971;Metcalf and Sanborn 1975), aquatic (Isensee 1976;Schuth et al 1974), and/or recirculating static (Ambrosi et al 1978;Isensee et al 1976Isensee et al , 1979a, and sitespecific models have been developed that emulate river (Lynch et al 1982;Maki and Johnson 1977;Rose and McIntire 1970) or paddy field (Chen et al 1982;Lee et al 1976;Wang et al 1992a) conditions. In Table 14 a long list of substances is presented that have been studied in model systems of one design or another.…”

Section: Model Ecosystemsmentioning

confidence: 99%

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Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

137

102

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The ecotoxicological assessment of pesticide effects in the aquatic environment should normally be based on a deep knowledge of not only the concentration of pesticides and metabolites found but also on the influence of key abiotic and biotic processes that effect rates of dissipation. Although the bioconcentration and bioaccumulation potentials of pesticides in aquatic organisms are conveniently estimated from their hydrophobicity (represented by log K(ow), it is still indispensable to factor in the effects of key abiotic and biotic processes on such pesticides to gain a more precise understanding of how they may have in the natural environment. Relying only on pesticide hydrophobicity may produce an erroneous environmental impact assessment. Several factors affect rates of pesticide dissipation and accumulation in the aquatic environment. Such factors include the amount and type of sediment present in the water and type of diet available to water-dwelling organisms. The particular physiological behavior profiles of aquatic organisms in water, such as capacity for uptake, metabolism, and elimination, are also compelling factors, as is the chemistry of the water. When evaluating pesticide uptake and bioconcentration processes, it is important to know the amount and nature of bottom sediments present and the propensity that the stuffed aquatic organisms have to absorb and process xenobiotics. Extremely hydrophobic pesticides such as the organochlorines and pyrethroids are susceptible to adsorb strongly to dissolved organic matter associated with bottom sediment. Such absorption reduces the bioavailable fraction of pesticide dissolved in the water column and reduces the probable ecotoxicological impact on aquatic organisms living the water. In contrast, sediment dweller may suffer from higher levels of direct exposure to a pesticide, unless it is rapidly degraded in sediment. Metabolism is important to bioconcentration and bioaccumulation processes, as is detoxification and bioactivation. Hydrophobic pesticides that are expected to be highly stored in tissues would not be bioconcentrated if susceptible to biotic transformation by aquatic organisms to more rapidly metabolized to hydrophilic entities are generally less toxic. By analogy, pesticides that are metabolized to similar entities by aquatic species surely are les ecotoxicologically significant. One feature of fish and other aquatic species that makes them more relevant as targets of environmental studies and of regulation is that they may not only become contaminated by pesticides or other chemicals, but that they constitute and important part of the human diet. In this chapter, we provide an overview of the enzymes that are capable of metabolizing or otherwise assisting in the removal of xenobiotics from aquatic species. Many studies have been performed on the enzymes that are responsible for metabolizing xenobiotics. In addition to the use of conventional biochemical methods, such studies on enzymes are increasingly being conducted using immunochemical met...

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Section: Other Pesticidesmentioning

confidence: 99%

Section: Model Ecosystemsmentioning

confidence: 99%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

137

102

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“…4. Whole body radioautograms offish exposed to 14C-CNP Radioautograms, a and b show the accumulation of 14C-CNP and its metabolites in viscera and intervertebral cartilage, respectively Lee et al (1976) also studied that distribution and fate of three diphenylether herbicides in a rice paddy model ecosystem. They found that nitrofen was relatively stable under model ecosystem conditions, and obtained the ecological magnification coefficient in Gambusia of 1546 for nitrofen, 867 for methoxy nitrofen and 49 for bifenox.…”

Section: Distribution Of Cnp and Its Metabolites In Fish Bodymentioning

confidence: 99%

Intake and excretion of 2,4,6-trichlorophenyl-4′-nitrophenyl ether by topmouth gudgeon,Pseudorasbora parva

Kanazawa¹,

Tomizawa²

1978

Arch. Environ. Contam. Toxicol.

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Abstract. When the freshwater fish, topmouth gudgeon, was exposed to continuous flow water containing 20 ppb of CNP (2,4,6-trichlorophenyl-4'-nitrophenyl ether), CNP concentration in the fish body gradually increased and reached equilibrium after seven days. CNP concentration and bioconcentration ratio (partition coefficient between fish body and water) after 15 days were 25.3 ppm and 1109, respectively. When the fish was transferred into clean water, the CNP taken into the fish body was slowly excreted and decreased to 0.115 ppm after 30 days. In order to examine distribution and metabolism of CNP in the fish body, an exposure test to static water containing 20 and 100 ppb of 14C-labeled CNP was conducted. The concentration of 14C-CNP equivalent after seven days was decreased in the following order: kidney, viscera except kidney and liver, fiver, head, muscle. More than 90% of the toluene-soluble fraction of the 14C in each organ was the parent compound (CNP), and no significant decrease in the concentration of ~4C-CNP equivalent in each organ of the fish was found seven days after transfer into clean water. Consequently it appears that CNP is fairly persistent in the fish body. Several metabolites in the toluene-soluble fraction of fish and water were detected by TLC. Among these metabolites, only amino-CNP and p-nitrophenol were indentified by GLC.2,4,6-Trichlorophenyl-4'-nitrophenyl ether (CNP) is a herbicide developed for controUing various species of weeds in.paddy fields as a substitute for pentachlorophenol which is highly toxic to aquatic organisms. At present, this herbicide is one of the herbicides which have widespread use in paddy fields of Japan.It is well known that the acute toxicity of CNP to aquatic organisms is relatively low; LC50 values in 48 hr for carp, and that in 3 hours for daphnid, are 290 and 40 ppm, respectively (Toyama andTakazawa 1971 andNishiuchi and Hasimoto 1967).This paper deals with studies on the intake, bioconcentration, metabolism, and excretion of CNP by the freshwater fish, topmouth gudgeon.

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“…The model ecosystem technique for the evaluation of pesticide biodegradability and ecological magnification was introduced in 1971 ( Metcalf and Kapoor 1971). Since then, several modified ecosystems were constructed to fit actual paddy field conditions (Chen, 1982 ;Lee, 1976).…”

Section: Introductionmentioning

confidence: 99%

Fate of 14C-lindane in a rice-fish model ecosystem

Mostafa¹,

El‐Arab²,

Zayed³

1987

J. of Env. Sc. & Hlth., Part B

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A model ecosystem has been used to evaluate the 14 impact of C-lindane on rice-fish agricultural system. 14 The distribution of C-residues among the constituents of the model ecosystem was studied over a period of 90 days. The insecticide was found to be readily absorbed by the roots and translocated to all parts of the rice plant. The peak level in the shoots (26 ppm) and roots (105 ppm) of plants was reached to within three weeks. Lindane was concentrated in fish and residues as high as 90 ppm could be detected after 30 days.The major part of the residues present in the different constituents of the ecosystem could be extracted with hexane and proved to contain soley the parent compound. The data obtained show that lindane possesses a relatively low biodegradability in fish and

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The Environmental Fate of Three Dichlorophenyl Nitrophenyl Ether Herbicides in a Rice Paddy Model Ecosystem

Cited by 19 publications

References 0 publications

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Intake and excretion of 2,4,6-trichlorophenyl-4′-nitrophenyl ether by topmouth gudgeon,Pseudorasbora parva

Fate of 14C-lindane in a rice-fish model ecosystem

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