Studies on the environmental fate of carbaryl as a function of pH

Fisher, Susan W.; Lohner, Timothy W.

doi:10.1007/bf01054913

Cited by 23 publications

(19 citation statements)

References 17 publications

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“…Based on the distribution of pesticides in the system, both a larger relative ratio of biomass to medium and a very shallow medium were found to cause significant effects on bioconcentration. The effect of medium pH was examined on carbaryl (101) and aldicarb (106) in model ecosystems (Fisher and Lohner 1986;Suora and Fisher 1986). The abiotic degradation profiles were affected by pH, but the distribution of the pesticides and their metabolites was not significantly changed for these carbamates.…”

Section: Model Ecosystemsmentioning

confidence: 99%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

136

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: Model Ecosystemsmentioning

confidence: 99%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

136

102

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“…Studies have found that recovery following pulsed exposure to carbaryl and others contaminants can be quite di!erent from continuous exposure (Kallander et al, 1997;Parsons and Surgeoner, 1991). In the same way, Fisher and Lohner (1986) demonstrated that the carbaryl stability was correlated with signi"cant changes in the acute toxicity. Another parameter which could contribute to the di!erences in recovery of ACHase inhibition is the sensitivity between species (Matsumara, 1985).…”

Section: Discussionmentioning

confidence: 91%

“…Consequently pH, temperature, and dissolved oxygen all in#uence carbaryl toxicity (Fisher and Lohner, 1986). This makes it di$cult to infer toxicity from measurements of carbaryl concentrations in water only.…”

Section: Discussionmentioning

confidence: 99%

“…pH, for instance, can alter the rate at which carbamates are decomposed by hydrolysis. Thus, the persistence of carbaryl in the water medium is short, for the most part, due to a rapid degradation (Fisher and Lohner, 1986); consequently, accumulation in organisms is low. However, it is a potent inhibitor of acetylcholinesterase (ACHase), even at sublethal concentrations (Murty and Ramani, 1992).…”

Section: Introductionmentioning

confidence: 98%

“…In the same way, there is evidence that snails are more sensitive to anticholinesterases than vertebrates (Singh and Agarwal, 1981;Edwards and Fisher, 1991). Besides that, some snails metabolized less carbaryl than other aquatic species (Fisher and Lohner, 1986); all these arguments suggest that ACHase inhibition in snails could be a trigger for remedial action in an ecotoxicological risk.…”

Section: Introductionmentioning

confidence: 99%

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Relationship between Toxicokinetics of Carbaryl and Effect on Acetylcholinesterase Activity in Pomacea patula Snail

Mora

Martínez‐Tabche²,

Sánchez-Hidalgo³

et al. 2000

Ecotoxicology and Environmental Safety

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Persistence of Chlorpyrifos in Soils under Different Moisture Regimes

Awasthi

Prakash

1997

Pestic. Sci.

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: Chlorpyrifos is an organophosphorus insecticide used to control insect pests in soil. The fate of chlorpyrifos in soils under di †erent moisture regimes is of interest because application directions specify soil-surface treatments for a number of agricultural and urban pests. Chlorpyrifos was degraded rapidly in all air-dry soils and slightly more slowly in soils at Ðeld capacity and/or under submerged conditions. Degradation rates were inÑuenced by clay-catalysed hydrolysis under air-dry conditions and neutral or alkaline hydrolysis under submerged conditions. Degradation was faster in Bellary soil (chromic haplustert) and slower in Chettalli soil (ustic palehumult) under all three moisture regimes. The calculated half-lives ranged from 1É6 to 10É0, 5É2 to 22É0 and 8É7 to 25É1 days under air-dry, Ðeld capacity and submergence respectively at an application rate of 10 mg kg~1.

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Studies on the environmental fate of carbaryl as a function of pH

Cited by 23 publications

References 17 publications

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Relationship between Toxicokinetics of Carbaryl and Effect on Acetylcholinesterase Activity in Pomacea patula Snail

Persistence of Chlorpyrifos in Soils under Different Moisture Regimes

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