Sulfotep

Last updated
Sulfotep
Sulfotep.svg
Sulfotep 3D ball.png
Names
Preferred IUPAC name
O1,O1,O3,O3-Tetramethyl 1,3-dithiodiphosphate
Other names
Sulfotep, Dithiophos, Dithion, Bladafum, Dithiofos, Dithione, Dithiotep, Pirofos, TEDP [1] [2]
Identifiers
3D model (JSmol)
ECHA InfoCard 100.020.905 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 222-995-2
PubChem CID
RTECS number
  • XN4375000
UNII
UN number 1704
  • CCOP(=S)(OCC)OP(=S)(OCC)OCC
Properties
C8H20O5P2S2
Molar mass 322.31 g·mol−1
AppearancePale yellow liquid [3]
Odor Garlic-like [3]
Density 1.196 g/cm3
Boiling point 136 to 139 °C (277 to 282 °F; 409 to 412 K) at 2 mm Hg
30 mg/L
Vapor pressure 0.0002 mmHg (20°C) [3]
Hazards [4] [5]
Occupational safety and health (OHS/OSH):
Main hazards
Poison [6]
NFPA 704 (fire diamond)
NFPA 704.svgHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
4
1
0
Flash point −18 °C (0 °F; 255 K)
Lethal dose or concentration (LD, LC):
22 mg/kg (mouse, oral)
25 mg/kg (rabbit, oral)
5 mg/kg (dog, oral)
5 mg/kg (rat, oral) [7]
38 mg/m3 (rat, 4 hr)
40 mg/m3 (mouse, 4 hr) [7]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 0.2 mg/m3 [skin] [3]
IDLH (Immediate danger)
10 mg/m3 [3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Sulfotep (also known as tetraethyldithiopyrophosphate and TEDP [8] ) is a pesticide commonly used in greenhouses as a fumigant. The substance is also known as Dithione, Dithiophos, and many other names. Sulfotep has the molecular formula C8H20O5P2S2 and belongs to the organophosphate class of chemicals. It has a cholinergic effect, involving depression of the cholinesterase activity of the peripheral and central nervous system of insects. [5] The transduction of signals is disturbed at the synapses that make use of acetylcholine. Sulfotep is a mobile oil that is pale yellow-colored and smells like garlic. [8] [9] It is primarily used as an insecticide.

Contents

History

Sulfotep was first commercially launched by Bayer in 1946. The first time that tetraethyl dithiopyrophosphate was registered to be used in the United States was in 1951. A Registration Standard for the chemical was issued by the Environmental Protection Agency in September 1988. Plans were made in 1999 by the Environmental Protection Agency to stop production of it by September 30, 2002, and to outlaw the use and distribution of products containing it by September 30, 2004. [10]

Chemistry

Synthesis

Sulfotep is synthesized by a reaction of tetraethyl pyrophosphate (TEPP) with sulfur. TEPP itself was first synthesized by Wladimir Moschnin [11] and Philippe de Clermont in 1854. [12] TEPP is made by a reaction of diethyl chlorophosphate with water to substitute the chloro group with a hydroxyl group. The product can react with another molecule of diethylchlorophosphate to form the ester, TEPP. In this reaction, pyridine is often used to neutralize the hydrochloric acid byproduct. [13]

Synthesis of sulfotep Synthese sulfotep.png
Synthesis of sulfotep

An alternative route to TEPP can be a reaction of diethyl chlorothiophosphate an aqueous solution of sodium bicarbonate (Na2CO3).

Properties

When heated to a temperature that is high enough for sulfotep to decompose, it gives off fumes of phosphorus and sulfur oxides, which are highly toxic. [8] [9] It can explode if containers of it are heated, and it can burn, although it does not do so easily. The chemical can also polymerize explosively. [14] The chemical also reacts to form toxic and flammable gases in the presence of hydrides and other reducing agents. It is able to corrode iron. [9] When it does this, it can release hydrogen gas. [14] The chemical has a specific gravity of 1.196 at 77 °F (25 °C) and its vapor density is 13.17 grams per liter at 25 °C (77 °F). [9] [15] Its melting point is 88 °C (190 °F) and its boiling point is between 272 °F (133 °C) and 282 °F (139 °C) at 2 mmHg. [8] [9] The chemical's sorption coefficient is 2.87 Log L/kg. Its Henry's Law constant is 0.000175 at 20 °C (68 °F). Its octanol-water partition coefficient is 3.9804 Log L/kg. Tetraethyl dithiopyrophosphate's diffusion coefficient in air is 0.015 cm2 per second and its diffusion coefficient in water is 0.0000055 cm2. [16]

Sulfotep's flash point is 178 °C (352 °F) and its enthalpy of vaporization is 59.4 kilojoules per mole. Its surface tension is 423 dynes per centimeter.[ citation needed ] The chemical has no Rule of 5 violations. [17] Its diffusivity in water is 0.63 × 10−5 cm2 per second. It is miscible with a large number of organic solvents, including methyl chloride and acetone [18] and its solubility in water is 30 milligrams per liter at 20 °C (68 °F). [15]

The alkaline and neutral hydrolysis of sulfotep results in the release of ethanol, phosphoric acid, and hydrogen sulfide. [19]

Applications

Sulfotep has applications as an insecticide, miticide, and acaricide. [9] However, because it does not leave behind a residue, it is less effective at these roles than DDT. [20] However, it is about as effective as the insecticide parathion. [21] Its use is restricted to greenhouses and ornamental plants. When the chemical is used as an insecticide, it is in the form of an impregnated smoke fumigant. [10] Sulfotep is used in greenhouses as a fumigant formulation to control aphids, spider mites, whiteflies and thrips. It is formulated as impregnated material in smoke generators containing 14 to 15% active ingredient. Smoke generators are placed in the greenhouses and then ignited using inserted sparklers to generate a thick white smoke for fumigation.

Sulfotep kills spider mites, mealybugs, whiteflies, and aphids. However, the chemical is not phytotoxic, unlike tetraethyl pyrophosphate. [22] However, it occasionally causes minor damage to plants, such as the slight puckering and cupping of leaves. [23] During several tests in the late 1940s, it was found to be the most toxic of several chemicals to whiteflies on vegetables, two-spotted spider mites on roses, and mealybugs on numerous plants. [22]

A mixture containing 5% sulfotep at the concentration of 0.5 grams of phosphate per 1000 cubic feet was found in tests in the late 1940s to kill 100% of nonresistant two-spotted spider mites and 68-97% of resistant two-spotted spider mites. Sulfotep aerosols killed 100% of the populations of a large number of insects, but only killed 98% of mealybugs in the same tests. [20] 88% of nonresistant spider mites can be killed be two minutes of exposure to a mixture containing 5% of the chemical, 98-99% can be killed after five to ten minutes, and all can be killed after 15 minutes. [23]

Mechanism of action

Sulfotep, just as all organophosphate pesticides, irreversibly inactivates acetylcholinesterase, which is essential to nerve function in insects, humans, and many other animals. Acetylcholinesterase normally hydrolyses acetylcholine after it was released in the synapse. When the acetylcholine is not degraded, it accumulates in the synaptic cleft. Thus, it keeps on stimulating the nerve. [24]

Metabolism

Metabolism of sulfotep Sulfotep metabolites.png
Metabolism of sulfotep

Uptake

Sulfotep is taken up well both orally, dermally as well as through inhalation. A few different organizations determined a maximum concentration sulfotep in the air. The maximum allowed concentration is 0.2 mg/m3.

Phase I

Sulfotep is desulfurated by either cytochrome P450 or the FAD-containing monooxygenases. In this reaction, the sulfur is replaced by oxygen, as seen in figure 2. The metabolites formed are monosulfotep and tetraethyl pyrophosphate (TEPP). To accomplish these reactions, a phospho-oxithirane ring is formed, which is highly reactive. This ring is thought to bind to acetylcholinesterase and cause toxicity. [25]

Phase II

The two Phase I metabolites are further transformed through a hydrolysis-reaction mediated by a type A-esterase. The products formed are O,O-diethyldithiophosphate and O,O-diethylphosphate. [25]

Excretion

An experiment in rats who were once given 0.4 mg radioactive phosphor-labelled sulfotep orally, has shown that sulfotep is excreted by both the kidneys (urine) and the liver (bile). The substance is completely metabolised. Two metabolites are found in the urine and faeces. The radioactivity showed that 85-91% was excreted in urine and 5-6% in the faeces. [24]

Toxicity

Acute toxic effects on animals

Sulfotep is toxic to some wildlife, including fish and aquatic invertebrates. It is also assumed by the Environmental Protection Agency to be toxic to birds. [10]

ExposureToxic level
Inhalationmg/m3
Mouse 1 hr155 [2] [26]
Mouse 4 hr40 [2] [26]
Rat 1 hr160-330 [2] [26]
Rat 4 hr38-59 [2] [26]
Oral LD50mg/kg
Cat3 [2] [26] [27]
Dog5 [2] [26] [27]
Mouse21.5-29.4 [2] [26] [27]
Rabbit25 [2] [26] [27]
Rat5-13.8 [2] [26] [27]
Dermal LD50mg/kg
Rat 4 hr262 [2]
Rat 7 d65 [2]
Intravenous LD50μg/kg
Mouse300 [2] [27]
Intramuscular LD50μg/kg
Mouse500 [2] [27]
Rat55 [2] [27]
Intraperitoneal LD50μg/kg
Mouse940 [2] [27]
Rat6600 [2] [27]
Subcutaneous LD50mg/kg
Mouse8 [2] [27]

Surviving animals completely recovered in 1–4 days.

Chronic and sub-chronic toxicity

A long-term exposure to a low concentration showed no toxicity. This was tested in rats. They were exposed to different concentrations of sulfotep. Exposed to the highest concentration of 2.83 mg/m3 for six hours a day, five days a week for 12 weeks, there was no change in appearance, behavior or body weight. The plasma cholinesterase activity decreased and the weight of the lungs of female rats increased. The red blood cell acetylcholinesterase activity was not affected. At lower concentrations, there were no changes at all.

The rats were orally exposed to 0, 5, 10, 20 or 50 ppm sulfotep for three months. Only their plasma cholinesterase activity and RBC acetylcholinesterase activity were decreased. No further symptoms were observed. Dogs who were orally exposed to 0, 0.5, 3, 5, 15 or 75 ppm (equivalent to 0–3.07 mg/kg/day) for 13 weeks, ate less and lost weight. The plasma cholinesterase activity was already affected by a sulfotep concentration of 3 ppm (or higher). Red blood cell-acetylcholinesterase was decreased at 75 ppm. Diarrhea and vomiting occasionally occurred at 15 ppm, but were common at 75 ppm. The brain cholinesterase activity was unaffected. [26]

Poisoning symptoms and treatment

According to the Occupational Safety and Health Administration, the upper limit on exposure of sulfotep to human skin is 0.2 milligrams per cubic meter. [14]

Sulfotep causes an organophosphate poisoning. This means that it had an effect on the activity of cholinesterase. There are differences for the indications of a sulfotep poisoning between inhalation, ingestion, intake by the skin and intake by the eyes. However, examples of poisoned greenhouse workers teach us an overall route of symptoms for a sulfotepp poisoning. Within the first hour after a poisonous intake of sulfotep people often suffer from nausea or headaches. After some hours diarrhea and vomiting may occur. People who inhaled sulfotep are often disorientated and have difficulties to breath. A poisonous dose may lead to a coma or death after 24 hours. The point at 24 hours after the poisoning is very important. If the dose is not lethal, the symptoms will slowly disappear after the point of 24 hours. [28] [29]

No embryotoxic or teratogenic effects occurred in tests. Neither were there any signs for carcinogenic effects. It was only mutagenic in one strain of S. typhimurium. In four other bacterial strains as well as in rats and mice it was not mutagenic at all.

There are two cases of acute toxicity known in man. The cholinesterase activity in these people was reduced. It took them 20 respectively 28 days to recover. [26] The most important poisoning symptoms are shown in the following table. [30]

ExposureSymptomsFirst aid treatmentOther treatments
Inhalationblue skin, convulsions, dizziness, drowsiness, headache, sweating, labored breathing, nausea, unconsciousness, weaknessFresh air or artificial respiration. Rest is important to prevent a respiration-arrest
Ingestioncramps in intestines, diarrhea, vomiting, confusionVomiting may only be induced in conscious peopleActive charcoal to absorb compound. Atropine as an antidote
Eyesirritation, redness, constriction of the pupil, loss of focusRinsing with plenty of water will lead to recovery of sight within 24 hours
Skin (may be absorbed)redness, irritation, sweating, twitching of the areaFirst rinse with plenty of water. Then wash the skin with water and soap

Related Research Articles

<span class="mw-page-title-main">Carbaryl</span> Chemical compound

Carbaryl is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid previously sold under the brand name Sevin, which was a trademark of the Bayer Company. The Sevin trademark has since been acquired by GardenTech, which has eliminated carbaryl from most Sevin formulations. Union Carbide discovered carbaryl and introduced it commercially in 1958. Bayer purchased Aventis CropScience in 2002, a company that included Union Carbide pesticide operations. Carbaryl was the third-most-used insecticide in the United States for home gardens, commercial agriculture, and forestry and rangeland protection. As a veterinary drug, it is known as carbaril (INN).

<span class="mw-page-title-main">Parathion</span> Chemical compound

Parathion, also called parathion-ethyl or diethyl parathion and locally known as "Folidol", is an organophosphate insecticide and acaricide. It was originally developed by IG Farben in the 1940s. It is highly toxic to non-target organisms, including humans, so its use has been banned or restricted in most countries. The basic structure is shared by parathion methyl.

<span class="mw-page-title-main">Malathion</span> Chemical compound

Malathion is an organophosphate insecticide which acts as an acetylcholinesterase inhibitor. In the USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa as mercaptothion.

<span class="mw-page-title-main">Chlorfenvinphos</span> Chemical compound

Chlorfenvinphos is an organophosphorus compound that was widely used as an insecticide and an acaricide. The molecule itself can be described as an enol ester derived from dichloroacetophenone and diethylphosphonic acid. Chlorfenvinphos has been included in many products since its first use in 1963. However, because of its toxic effect as a cholinesterase inhibitor it has been banned in several countries, including the United States and the European Union. Its use in the United States was cancelled in 1991.

<span class="mw-page-title-main">Ethion</span> Chemical compound

Ethion (C9H22O4P2S4) is an organophosphate insecticide. Ethion is known to affect a neural enzyme called acetylcholinesterase and prevent it from working.

<span class="mw-page-title-main">Diazinon</span> Chemical compound

Diazinon, a colorless to dark brown liquid, is a thiophosphoric acid ester developed in 1952 by Ciba-Geigy, a Swiss chemical company. It is a nonsystemic organophosphate insecticide formerly used to control cockroaches, silverfish, ants, and fleas in residential, non-food buildings. Diazinon was heavily used during the 1970s and early 1980s for general-purpose gardening use and indoor pest control. A bait form was used to control scavenger wasps in the western U.S. Diazinon is used in flea collars for domestic pets in Australia and New Zealand. Diazinon is a major component in the "Golden Fleece" brand sheep dip. Residential uses of diazinon were outlawed in the U.S. in 2004 because of human health risks but it is still approved for agricultural uses. An emergency antidote is atropine.

Chloropicrin, also known as PS (from Port Sunlight) and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I. Its chemical structural formula is Cl3CNO2.

<span class="mw-page-title-main">Azinphos-methyl</span> Chemical compound

Azinphos-methyl (Guthion) is a broad spectrum organophosphate insecticide manufactured by Bayer CropScience, Gowan Co., and Makhteshim Agan. Like other pesticides in this class, it owes its insecticidal properties to the fact that it is an acetylcholinesterase inhibitor. It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act, and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.

<span class="mw-page-title-main">Dichlorvos</span> Insect killing chemical, organophosphate

Dichlorvos is an organophosphate widely used as an insecticide to control household pests, in public health, and protecting stored products from insects. The compound has been commercially available since 1961 and has become controversial because of its prevalence in urban waterways and the fact that its toxicity extends well beyond insects. Since 1988, dichlorvos cannot be used as a plant protection product in the EU.

<span class="mw-page-title-main">Phosmet</span> Organophosphate non-systemic insecticide

Phosmet is a phthalimide-derived, non-systemic, organophosphate insecticide used on plants and animals. It is mainly used on apple trees for control of codling moth, though it is also used on a wide range of fruit crops, ornamentals, and vines for the control of aphids, suckers, mites, and fruit flies.

<span class="mw-page-title-main">Dimethoate</span> Chemical compound

Dimethoate is a widely used organophosphate insecticide and acaricide. It was patented and introduced in the 1950s by American Cyanamid. Like other organophosphates, dimethoate is an acetylcholinesterase inhibitor which disables cholinesterase, an enzyme essential for central nervous system function. It acts both by contact and through ingestion. It is readily absorbed and distributed throughout plant tissues, and is degraded relatively rapidly. One of the breakdown products of dimethoate is omethoate, a potent cholinesterase inhibitor, is ten times more toxic than its parent compound.

<span class="mw-page-title-main">Methiocarb</span> Chemical compound

Methiocarb is a carbamate pesticide which is used as an insecticide, bird repellent, acaricide and molluscicide since the 1960s. Methiocarb has contact and stomach action on mites and neurotoxic effects on molluscs. Seeds treated with methiocarb also affect birds. Other names for methiocarb are mesurol and mercaptodimethur.

<span class="mw-page-title-main">Demeton</span> Chemical compound

Demeton, sold as an amber oily liquid with a sulphur like odour under the name Systox, is an organophosphate derivative causing irritability and shortness of breath to individuals repeatedly exposed. It was used as a phosphorothioate insecticide and acaricide and has the chemical formula C8H19O3PS2. Although it was previously used as an insecticide, it is now largely obsolete due to its relatively high toxicity to humans. Demeton consists of two components, demeton-S and demeton-O in a ratio of approximately 2:1 respectively. The chemical structure of demeton is closely related to military nerve agents such as VX and a derivative with one of the ethoxy groups replaced by methyl was investigated by both the US and Soviet chemical-weapons programs under the names V.sub.X and GD-7.

<span class="mw-page-title-main">Mevinphos</span> Chemical compound

Mevinphos is an organophosphate insecticide that acts as an acetylcholinesterase inhibitor to control insects in a wide range of crops. It is most commonly used for the control of chewing and sucking insects, as well as spider mites. Common synonym names are duraphos, fosdrin, menite, mevinfos, mevinox, phosdrin, and phosdrine. It is not allowed in the EU anymore.

<span class="mw-page-title-main">Carbophenothion</span> Chemical compound

Carbophenothion also known as Stauffer R 1303 as for the manufacturer, Stauffer Chemical, is an organophosphorus chemical compound. It was used as a pesticide for citrus fruits under the name of Trithion. Carbophenothion was used as an insecticide and acaricide. Although not used anymore it is still a restricted use pesticide in the United States. The chemical is identified in the US as an extremely hazardous substance according to the Emergency Planning and Community Right-to-Know Act.

<span class="mw-page-title-main">Tetraethyl pyrophosphate</span> Chemical compound

Tetraethyl pyrophosphate, abbreviated TEPP, is an organophosphate compound with the formula [(C2H5O)2P(O)]2O. It is the tetraethyl derivative of pyrophosphate (P2O74-). It is a colorless oil that solidifies near room temperature. It is used as an insecticide. The compound hydrolyzes rapidly.

<span class="mw-page-title-main">Terbufos</span> Chemical compound

Terbufos is a chemical compound used in insecticides and nematicides. It is part of the chemical family of organophosphates. It is a clear, colourless to pale yellow or reddish-brown liquid and sold commercially as granulate.

<span class="mw-page-title-main">Triamiphos</span> Chemical compound

Triamiphos (chemical formula: C12H19N6OP) is an organophosphate used as a pesticide and fungicide. It is used to control powdery mildews on apples and ornamentals. It was discontinued by the US manufacturer in 1998.

<span class="mw-page-title-main">Triazofos</span> Chemical compound

Triazofos is a chemical compound used in acaricides, insecticides, and nematicides.

<span class="mw-page-title-main">EPN (insecticide)</span> Chemical compound

EPN is an insecticide of the phosphonothioate class. It is used against pests such as European corn borer, rice stem borer, bollworm, tobacco budworm, and boll weevil.

References

  1. Eula Bingham, Barbara Cohrssen, and Charles H. Powell. Patty's toxicology. Vol. 7 (5th ed.). John Wiley and Sons.{{cite book}}: CS1 maint: multiple names: authors list (link)
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 CID 19395 from PubChem
  3. 1 2 3 4 5 NIOSH Pocket Guide to Chemical Hazards. "#0586". National Institute for Occupational Safety and Health (NIOSH).
  4. Product detail chemkoo.com [ dead link ]
  5. 1 2 Georg Kimmerle and Otto R. Klimmer, ‘’Acute and Subchronic Toxicity of Sulfotep’’, Arch. Toxicol. 33, 1-16 (1974)
  6. Sulfotep toxicity
  7. 1 2 "TEDP". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  8. 1 2 3 4 Tetraethyl dithiopyrophosphate , retrieved July 30, 2013
  9. 1 2 3 4 5 6 TETRAETHYL DITHIOPYROPHOSPHATE , retrieved July 29, 2013
  10. 1 2 3 Sulfotepp (PDF), October 1999, retrieved July 31, 2013
  11. Fest, Christa; Schmidt, Karl-Julius (1982). The Chemistry of Organophosphorus Pesticides. Springer. doi:10.1007/978-3-642-68441-8. ISBN   978-3-642-68443-2. S2CID   33095322. The history of cholinesterase inhibitors: who was Moschnin(e)?
  12. Toy, A. D. F. (1948). "The Preparation of Tetraethyl Pyrophosphate and Other Tetraalkyl Pyrophosphates". Journal of the American Chemical Society. 70 (11): 3882–3886. doi:10.1021/ja01191a104. PMID   18102975.
  13. Thomas A. Unger, Pesticide synthesis handbook – page 387
  14. 1 2 3 OSHA/EPA Occupational Chemical Database , retrieved February 15, 2017
  15. 1 2 John H. Montgomery (December 12, 2010), Groundwater Chemicals Desk Reference, Fourth Edition, CRC Press, ISBN   9781420009132
  16. Tetraethyl dithiopyrophosphate , retrieved July 30, 2013
  17. TETRAETHYL DITHIOPYROPHOSPHATE , retrieved July 31, 2013
  18. Keith, Lawrence H.; Walters, Douglas B. (1992), National Toxicology Program's Chemical Solubility Compendium, CRC Press, ISBN   9780873716536
  19. Donald Mackay, Robert S. Boethling (editors) (2000), Handbook of Property Estimation Methods for Chemicals: Environmental Health, CRC Press, ISBN   9781420026283 {{citation}}: |author= has generic name (help)
  20. 1 2 Floyd F. Smith, R.A. Fulton (June 1950), Tetraethyl dithiophosphate in Aerosols for the Control of Greenhouse Insects, Washington, D.C. : U.S. Department of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine
  21. Haz-Map, April 2013, retrieved July 31, 2013
  22. 1 2 Floyd F. Smith, R.A. Fulton (June 1950), Tetraethyl dithiophosphate in Aerosols for the Control of Greenhouse Insects, Washington, D.C. : U.S. Department of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine
  23. 1 2 Floyd F. Smith, R.A. Fulton (June 1950), Tetraethyl dithiophosphate in Aerosols for the Control of Greenhouse Insects, Washington, D.C. : U.S. Department of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine
  24. 1 2 Sulfotep, Bayer MAK 24, Lieferung 1997
  25. 1 2 Timbrell John A., Principles of biochemical toxicology 4th edition 2009. Informa Healthcare New York. pp 91 & 99
  26. 1 2 3 4 5 6 7 8 9 10 11 Eula Bingham, Barbara Cohrssen and Charles H. Powell. Patty’s toxicology (5th edition. Vol. 7. John Wiley and sons inc.)
  27. 1 2 3 4 5 6 7 8 9 10 11 Richard J. Lewis, Sr. Sax’s Dangerous properties of industrial materials (10th edition. Vol. 3. John Wiley and sons inc.)
  28. "ICSC:NDUT0985 International Chemical Safety Cards (WHO/IPCS/ILO) | CDC/NIOSH". www.cdc.gov. Archived from the original on 2008-01-24.
  29. Chemwatch, Sulfotep sc-251093. Material Safety Data Sheet. https://datasheets.scbt.com/sc-251093.pdf
  30. International Chemical Safety Cards, ICSC: 0985, https://www.cdc.gov/niosh/ipcsndut/ndut0985.html