Elimite
Bioenergetics of acclimation to permethrin (NRDC-143) by rainbow trout.

Kumaraguru AK, Beamish FW.

Metabolic rates associated with sustained, prolonged and critical swimming speeds were examined in 10 g trout exposed to 5% 96 hr LC50 (0.75 microgram X l-1) and 10% 96 hr LC50 (1.50 micrograms X l-1) at 12 degrees C. Permethrin did not influence the metabolic cost for swimming at sustained and prolonged speeds. Basal metabolic rate increased on initial exposure to permethrin reaching maximum values after 7 days and declined to the control level after 13 days in 5% and after 32 days in 10% 96 hr LC50. Critical swimming speeds were adversely affected in a manner reflective of the effects of permethrin on basal metabolic rate. Elevation in basal metabolic rate in fish exposed to permethrin was a result of increased energy requirements due to physiological stress, detoxication and tissue repair.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6138193&dopt=Abstract permethrin Elimite



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Occupational exposure to some synthetic pyrethroids (permethrin and fenvalerate).

Kolmodin-Hedman B, Swensson A, Akerblom M.

In a two-step study on exposure control method for occupational handling of permethrin was developed. Air sampling on a filter can be used in case of exposure to permethrin in powder form. The detection limit is 0.001 mg/m3. If biological sampling is used, the acid metabolite moiety in the urine must be monitored. However, the uptake after exposure to permethrin in forestry was too low, and no urine concentration could be found. The detection limit is 0.1 microgram/ml. Six persons in a plant nursery and six planters were studied in this way. Interviews were conducted with 139 planters. Irritative symptoms form the skin and upper respiratory tract were reported in 73% for fenvalerate, 63% for permethrin (trans/cis 75/25) and 33% for permethrin (trans/cis 60/40).

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6214240&dopt=Abstract permethrin Elimite



Elimite
Pyrethroid insecticide residues on vegetable crops.

Ripley BD, Ritcey GM, Harris CR, Denomme MA, Brown PD.

Pesticide and Trace Contaminants Laboratory, Laboratory Services, University of Guelph, Guelph, Ontario, Canada N1H 8J7. bripley lsd.uoguelph.ca

Pyrethroid insecticides were applied on various vegetable crops as foliar treatments to determine dissipation rates. On Chinese broccoli (Guy Lon), Chinese mustard (Pak Choi) and Chinese cabbage (Kasumi, napa), fenvalerate was persistent with residues of 0.10, 0.14 and 0.11 mg kg-1, respectively, by day 21. Cypermethrin residues on head lettuce were below 0.1 mg kg-1 by day 10 but on the leafier romaine and endive varieties it was more persistent and required 14-19 days to dissipate below this concentration. After three applications, residues of cypermethrin in harvested carrots and of permethrin in eggplant were not detected on the day of application. On asparagus, deltamethrin and cypermethrin residues declined to less than 0.1 mg kg-1 by days 1 and 2, respectively; permethrin was more persistent, requiring more than 2 days to decline to less than 0.1 mg kg-1. Deltamethrin on dry (cooking) and Spanish onions was not detected on the day of application. On tomatoes, the concentration of permethrin was 0.093 mg kg-1 on the day of application and declined to about 0.05 mg kg-1 after 2-4 days. In general, permethrin, cypermethrin and deltamethrin residues declined to acceptable concentrations within an acceptable pre-harvest interval. Fenvalerate may be too persistent on these speciality crops unless a maximum residue limit > 0.1 mg kg-1 is permitted.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11517721&dopt=Abstract permethrin Elimite



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Effects of pyrethroids on lymphocyte membrane lipid packing order.

Stelzer KJ, Gordon MA.

The effects of pyrethroids on the membrane lipid packing order of murine splenic lymphocytes have been investigated by utilizing the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene. Fluorescence anisotropy and lifetime measurements indicated alterations in the environment of the probe at pyrethroid concentrations near 1 microM. Decreased packing order of membrane lipids was detected for permethrin and cypermethrin by decreased anisotropy values. Permethrin and cypermethrin decreased fluorescence lifetime over a concentration range similar to that causing anisotropy changes. Anisotropy was predominantly increased in the presence of fluvalinate and fenpropathrin, indicating pronounced quenching of fluorescence by these compounds. However, the anisotropy changes in response to fluvalinate and fenpropathrin occurred at concentrations which were similar to effective concentrations of permethrin and cypermethrin. Compared to the other pyrethroids tested, allethrin required approximately 10 fold higher concentrations to alter anisotropy and lifetime values. Effects of pyrethroids on the phase transition of dipalmitoyl phosphatidylcholine liposomes were also studied to give further insight into the membrane interactions of these compounds. Results from the liposomal system indicate that the effects of pyrethroids on membrane order which were observed in the lymphocyte may be generalizable to other cell types.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6527010&dopt=Abstract permethrin Elimite



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Comparisons of permethrin formulations and application methods for northern fowl mite control on caged laying hens.

Arthur FH, Axtell RC.

Formulations of permethrin (Ectiban), a synthetic pyrethroid, as an emulsifiable concentrate (EC), wettable powder (WP), and dust were nearly equally effective for 9 or more weeks for control of the northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), on caged laying hens under environmentally controlled conditions. The permethrin was applied to the vent area as .05% active ingredient (AI) spray of the diluted EC or WP at 40 ml per bird, .1% AI mist of the diluted EC at 20 ml per bird, and 4.5 g per bird of the .25% AI dust. Dilute sprays of .05% permethrin prepared from the EC and WP and applied at 40 ml per bird were more effective in a commercial caged-laying hen house for northern fowl mite control than were .5% sprays of tetrachlorvinphos (Rabon), Ravap, and carbaryl (Sevin). Satisfactory mite control was obtained with .6% permethrin prepared from the EC and misted at the rate of 2.5 ml per bird. Low volume, high concentration misting of permethrin was a promising method for mite control with satisfactory control achieved with .2% AI at 5 ml per bird and .6% AI at 2.5 ml per bird.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6808475&dopt=Abstract permethrin Elimite