Interactions and transformations of chlorpyrifos in aqueous and colloidal systems

Wu, Jigang

doi:10.31274/rtd-180813-13643

Cited by 3 publications

(1 citation statement)

References 33 publications

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“…After collection, jars were stored at 4°C until analysis. Concentrations of chlorpyrifos were measured with solid‐phase microextraction and gas chromatography (GC) [19]. A solid‐phase microextraction fiber coated with 85‐μm polyacrylate (Supelco, Bellefonte, PA, USA) was immersed into 10‐ml water samples that were stirred at a constant rate for 30 min.…”

Section: Methodsmentioning

confidence: 99%

Acute toxicity and cholinesterase inhibition in larval and early juvenile walleye exposed to chlorpyrifos

Phillips

Summerfelt

et al. 2002

Enviro Toxic and Chemistry

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Application of organophosphorus (OP) insecticides to agricultural fields during the spring often overlaps the period of spawning, egg incubation, and larval stages of fish species such as walleye (Stizostedion vitreum). Because life stage can affect uptake, distribution, and effects of contaminants, our objective was to identify the most sensitive life stage of walleye tochlorpyrifos, a broad-spectrum OP insecticide. Prolarvae (yolk sac, endogenous feeding stage) were least sensitive to chlorpyrifos (median lethal concentration [LC50] = 225-316 microg/L), and postlarvae I (oil globule, exogenous feeding stage) were less sensitive (LC50 = 24-29 microg/L) than postlarvae II (oil globule absent; LC50 = 12-13 microg/L). The differences in sensitivity of the larval stages coincide with stages of gill development. Gill filaments were absent until the end of the prolarval stage, and development of secondary lamellae did not occur until the end of the postlarval I stage. Juvenile fish were less sensitive than postlarval stages, but did not differ significantly among the juvenile ages tested. The LC50s ranged from 37 to 45 microg/L for 30- and 90-d-old juvenile walleye, respectively. Larval walleye survived when cholinesterase (ChE) activity was inhibited by as much as 90%; however, 60- and 90-d-old juvenile walleye did not survive when ChE activity was inhibited more than 71%.

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Section: Methodsmentioning

confidence: 99%

Acute toxicity and cholinesterase inhibition in larval and early juvenile walleye exposed to chlorpyrifos

Phillips

Summerfelt

et al. 2002

Enviro Toxic and Chemistry

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Toxicity of Chlorpyrifos Adsorbed on Humic Colloids to Larval Walleye ( Stizostedion vitreum )

Phillips

Summerfelt

et al. 2003

Archives of Environmental Contamination and Toxicology

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After application, organophosphorus insecticides (OPs) are often strongly adsorbed to soil constituents. Because of their relatively low water solubility, OPs may be transferred from field to stream adsorbed on suspended solids. However, we are not aware of research done to evaluate the bioavailability (i.e., toxicity) of OPs transported on suspended solids to fish. We conducted 48-h static toxicity tests to determine the toxicity of chlorpyrifos in aqueous solution and adsorbed on calcium-saturated humic acid (HA) to three larval stages of walleye (Stizostedion vitreum). Three concentrations of chlorpyrifos adsorbed on HA, a HA control, and a chlorpyrifos-only treatment were tested. Fish that survived the 48-h static toxicity tests were analyzed to determine total cholinesterase (ChE) activity. In general, survival of all larval stages of walleye exposed to chlorpyrifos-HA complexes was less than that of walleye exposed to HA controls and the chlorpyrifos-only treatment, which were not toxic to walleye. Cholinesterase inhibition of larval walleye exposed to chlorpyrifos-HA complexes was similar to the ChE inhibition observed in larval walleye exposed to chlorpyrifos in the aqueous phase. These laboratory experiments indicate potential toxicity of chlorpyrifos-soil complexes to larval fish.

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Electrical conductivity spectra of smectites as influenced by saturating cation and humidity

Logsdon¹,

Laird²

2004

Clays and clay miner.

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Electrical conductivity is an important soil property related to salinity, and is often used for delineating other soil properties. The purpose of this study was to examine the influence of smectite properties on the complex electrical conductivity spectra of hydrated smectitic clays. Four smectites were saturated with Ca, Mg, Na or K and equilibrated at four relative humidities ranging from 56 to 99%. X-ray diffraction was used to determine fractions of the various smectite layer hydrates (0 to 4 layers of interlayer water molecules) in each sample. A vector network analyzer was used to determine the real component of the complex electrical conductivity spectra (σ′) for frequencies (f) ranging from 300 kHz to 3 GHz. Values of the dc electrical conductivity(σ0), the frequency where the slope changes in the spectra (fr), and the slope at the high-frequency end of the spectra (n) were determined by fitting σ′ to σ′(f) = σ0(1 + f/fr)n. Both σ0 and fr increased with the total amount of water, the amount of interlayer water, and, for saturating cations in the order K < Mg < Ca < Na. The opposite trends were observed for n. The values of these parameters were influenced by the type of smectite, but the trends were not consistent for the effect of layer charge. The results indicate that interlayer water in smectites contributes to the electrical conductivity of hydrated smectites, and that polarization of water by local electrical fields has a substantial influence on the complex electrical conductivity spectra of smectites. The accuracy of salinity estimates for soils and sediments that are based on conductivity measurements maybe adversely affected unless the effects of hydrated clays on electrical conductivity are considered.

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Interactions and transformations of chlorpyrifos in aqueous and colloidal systems

Cited by 3 publications

References 33 publications

Acute toxicity and cholinesterase inhibition in larval and early juvenile walleye exposed to chlorpyrifos

Acute toxicity and cholinesterase inhibition in larval and early juvenile walleye exposed to chlorpyrifos

Toxicity of Chlorpyrifos Adsorbed on Humic Colloids to Larval Walleye ( Stizostedion vitreum )

Electrical conductivity spectra of smectites as influenced by saturating cation and humidity

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