Isobenzan

(Non-Specific -- Dry Insecticide) Avoid breathing dusts and fumes from burning material. Keep upwind. Avoid bodily contact with the material. Wear full protective clothing including boots, protective gloves, goggles, and wear self-contained breathing apparatus.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

0.091 [mg/m3]

1.0 [mg/m3]

6.0 [mg/m3]

For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)

Personnel protection: ... Wear appropriate chemical protective gloves, boots and goggles. .... /Organochlorine pesticide, liquid; Organochlorine pesticide, solid, toxic/

... Beagles developed convulsions when the concn of isobenzan in their blood ranged from 0.042 to 0.072 ppm.

When male and female rats were given a single iv injection of 14C-isobenzan (15 ug/kg bw), the radioactivity in the blood of males 48 hr later was 0.04% of the applied dose and in females was 0.37%. The radioactivity in the organs and tissues ranged between 0.01 and approximately 1.5% of the applied dose, concentrations being lower in females than in males. In abdominal fat, the concentrations were 19.2% in males and 26.6% in females and, in muscle, 12.3% and 9.3%, respectively.

LD50 Mallard female, 5-7 month old, oral 4.15 mg/kg (95% confidence limit 2.47-6.97 mg/kg) /Sample purity 99%/

LD50 Coturnix quail (female) oral 4.2 mg/kg bw /from table/

LD50 Quiscalus quiscula (grackle) oral 1.3 mg/kg bw /from table/

LD50 Columba liva (pigeon) oral 10 mg/kg bw /from table/

For more Ecotoxicity Values (Complete) data for ISOBENZAN (10 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 4,700(SRC), determined from a structure estimation method(2), indicates that isobenzan is expected to have slight mobility in soil(SRC). Volatilization of isobenzan from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.9X10-8 atm-cu m/mole(3), using a fragment constant estimation method(3). Isobenzan is not expected to volatilize from dry soil surfaces(SRC) based on a vapor pressure of 2.92X10-6 mm Hg(4). Biodegradation in soil is not expected to be an important environmental fate process(SRC). The percentage of isobenzan in soil was shown to decrease with increasing clay content in the soil; no isobenzan was recovered after 4-8 days of exposure at 45 °C. On the other hand, moist soils showed a diminished ability to degrade isobenzan after 4 days at 45 °C with the exception of sandy soils(5). A soil half-life of 20-26 weeks depending on soil content has also been calculated(6).

Terrestrial Fate: The behavior of isobenzan in soil was investigated in laboratory tests. Eight types of soil were used ranging from sand to sandy clay, the percentage of sand varying from 93 to 56% and the percentage of clay from 4 to 35%. Following percolation with hexane, the percentage of isobenzan in the eluate fraction was shown to decrease with increasing content of clay in the soil (starting at about 30% clay). Except in the case of sand with a high organic matter content (6-19%), no isobenzan was recovered from the dry soils after 4-8 days of exposure at 45 °C. When the soils were moistened with water and exposed at 45 °C for 4 days, degradation was markedly diminished, with the exception of sand with high organic matter.

Terrestrial Fate: After isobenzan is applied to the soil, a rapid initial loss occurs, after which the remaining cmpd decays at a much slower rate. It persists in soil from 2-7 yr depending on type of soil.

Terrestrial Fate: 95% /telodrin/ disappearance from soils: 2-4 yr

For more Environmental Fate (Complete) data for ISOBENZAN (7 total), please visit the HSDB record page.

Isobenzan was detected but concns not reported in the FDA program for monitoring pesticide residues in foods during 1978-1982; 49,877 samples of raw agricultural commodities were analyzed(1). Isobenzan was detected, concns not reported, in 3 fruit samples during 1970-1971(2).

Three Jersey cows were fed for 28 days at concentrations of technical isobenzan of 0, 0.005, or 0.02 mg/kg in their daily ration (average ration, 20 kg per cow). Residues found in the milk of the cow fed 0.005 mg/kg increased from 0.4 ug/L to 2 ug/L at the end of the feeding period and decreased rapidly thereafter. Higher residues of up to 7.7 ug/L were present in the milk from the cow fed 0.02 mg/kg, which decreased to 1.5 ug/L whole milk 10 weeks after the last day of dosing.

It antagonizes the action of the neurotransmitter gamma-aminobutyric acid (GABA) acting at the GABA-A receptors, effectively blocking the GABA-induced uptake of chloride ions and causing hyperexcitability of the central nervous system. It also inhibits Na+ K+ ATPase and Ca2+ and Mg2+ ATPase which are essential for the transport of calcium across membranes. This results in the accumulation of intracellular free calcium ions, which promotes release of neurotransmitters from storage vesicles, the subsequent depolarization of adjacent neurons, and the propagation of stimuli throughout the central nervous system. It also causes increased lipid peroxidation, decreased membrane fluidity, and DNA damage in hepatocytes, but the exact mechanism is unknown. (T10, L112)

/FIELD STUDIES/ Five sandy loam plots of pasture in New Zealand were treated with telodrin (15% emulsifiable concentrate) at a rate of 2 kg isobenzan/ha in June 1962. The populations of all recorded groups (grass grub, porina, collembola, diptera, hemiptera, coleoptera, mites, and earthworms), except nematodes, were drastically reduced. There was no recovery in the populations of any of the affected groups during the period of up to October 1965. In silt loam plots treated with isobenzan granules (1 kg/ha) in April 1964, the populations of coleoptera, collembola, diptera, mites, and earthworms were all reduced, but to a lesser extent than in the test using 2 kg/ha. Grass grub and hemiptera were not significantly affected,and nematode numbers were elevated 2 yr after treatment.

/FIELD STUDIES/ When loose sandy soil in New Zealand was treated with 2.25 kg isobenzan/ha as 5% granules, the population reduction, 1-18 wk after treatment, was 90-100% for larval coleoptera and lepidoptera and 75% for diptera and earthworms. The number of surface arthropods, 5-15 days after treatment, was reduced by 45%. Six months after treatment, little effect was found on nematodes (13% reduction), bacteria (18% reduction), and fungi (7% increase).

/AQUATIC SPECIES/ Groups of 5 adult Rasbora heteromorpha (Harlequin fish) were exposed for 2 hr at a temp of 20 °C to water (pH 7.2) containing isobenzan (99%), dissolved in DMSO at a concentration of 0.01, 0.1, or 1 mg/L. The fish were then /placed in/ clean water and observed for an additional 48 hr. The treatment with 1 mg/L caused disorientation and the fish became excited by external stimuli, lost ability to swim, and finally all died within 1 hr. In some cases, they appeared to be convulsive. Isobenzan at 0.1 mg/L caused similar symptoms; within 2 hr of exposure, all five fish died. No fish died at 0.01 mg/L, but slight changes in swimming behavior were observed. When guppies (Poecilia reticulata) were tested in the same way, the symptoms of intoxication and susceptibility were similar to those in Harlequin fish, but the guppies were slower to react.

/BIRDS and MAMMALS/ Sign of intoxication /for female mallard/: Ataxia, fasciculation, tenseness, swimming backwards, tail high and fanned, loss of righting reflex, circling, opisthotonos. Signs appeared as soon as 30 min and mortalities occurred about 2 hr after treatment. Survivors appeared normal by the next day, but lost moderate amount of body wt by the end of the 14-day observation period.

/BIRDS and MAMMALS/ When groups of five male and five female Japanese quail (Coturnix coturnix japonica) were fed diets containing 2 or 10 mg isobenzan/kg, the mean survival time in the high-dose group was 6.9 days (range, 2-20 days). The residues in the liver and brain averaged 3.4 mg/kg and 1.4 mg/kg, respectively. In the low-dose group, the mean survival time was 45.9 days (range, 19-65 days) and the average residues in liver and brain were 6 mg/kg and 1.6 mg/kg, respectively. The concentration of isobenzan in the liver of birds fed 2 mg/kg was significantly higher than that in the high-dose group, but the concentration in the brain showed no difference.

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. isobenzan is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 100 or 1,000 lbs. Extremely hazardous substances that are solids are subject to either of two threshold planning quantities ... The lower quantity applies only if the solid exists in powdered form and has a particle size less than 100 microns; or is handled in solution or in molten form; or meets the criteria for a National Fire Protection Association (NFPA) rating of 2, 3 or 4 for reactivity. If the solid does not meet any of these criteria, it is subject to the upper ... threshold planning quantity ... .

Used as insecticide; [Merck Index] Used as a broad spectrum contact and stomach insecticide; [INCHEM]

No longer registered as a pesticide for use in the US; [HSDB] Restricted due to environmental persistence and toxicity; [INCHEM]

Farming (Pesticides) [Category: Industry]

For isobenzan (USEPA/OPP Pesticide Code: 058501) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Insecticide

It is used as a pesticide. (L111)

Technical Grade: Not less than 95% (wt/wt)

It was supplied in the form of emulsifiable concentrate, dust, and granules ...

Cyclodiene resistance in the housefly, sheep blowfly, and mosquito is most strongly shown to dieldrin, aldrin, and chlordane and most weakly to isobenzan.

... Chlordane-resistant Blattella are strongly cross-resistant to isobenzan ...

The cross-resistance pattern of cyclodiene-resistant root maggots (Hylemya antiqua, brassicae, and liturata) has been extensively studied by tests on the adult flies. ... The cross-resistance is ... moderate to ... isobenzan ...

Isobenzan was made and sold under the trade name Telodrin. ... Isobenzan was manufactured for Shell in Holland. Production started in 1958 and was discontinued in September 1965.

Isobenzan had uses in Europe similar to heptachlor, but production was discontinued in 1966 because of its very high mammalian toxicity.