Names | |
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Preferred IUPAC name O-Ethyl S,S-dipropyl phosphorodithioate | |
Other names Ethoprophos, Prophos, Mocap | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.032.851 |
EC Number |
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KEGG | |
PubChem CID | |
RTECS number |
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UNII | |
UN number | 3018 |
CompTox Dashboard (EPA) | |
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Properties | |
C8H19O2PS2 | |
Molar mass | 242.33 g·mol−1 |
Appearance | Colourless to yellow clear liquid |
Odor | Mercaptan-like |
Density | 1.069 g/ml |
Melting point | <-70 °C (-94 °F, 203 K) |
Boiling point | 244.3 °C (471.7 °F, 517.5 K) (decomposes) |
1.3-1.4 mg/L (water) | |
Vapor pressure | 78 mPa (20 °C), 128 mPa (25 °C) |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Toxic |
GHS labelling: | |
Danger | |
H301, H310, H317, H330, H410 | |
P260, P261, P262, P264, P270, P271, P272, P273, P280, P284, P301+P310, P302+P350, P302+P352, P304+P340, P310, P320, P321, P322, P330, P333+P313, P361, P363, P391, P403+P233, P405, P501 | |
Flash point | 141 °C |
280 °C (536 °F; 553 K) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Ethoprophos (or ethoprop) is an organophosphate ester with the formula C8H19O2PS2. [1] It is a clear yellow to colourless liquid that has a characteristic mercaptan-like odour. It is used as an insecticide and nematicide [2] and it is an acetylcholinesterase inhibitor. [3]
Ethoprop can be synthesised by reacting phosphoryl chloride with two equivalents of n-propylmercaptan and one equivalent of sodium ethoxide. A second pathway is reacting n-propylmercaptan and sodium ethoxide with phosphorus trichloride to yield ethoxy-bis(propylsulfanyl)phosphane, which can then be oxidized by hydrogen peroxide to yield the product. [4]
Ethoprop is used as an insecticide against soil insects like wireworms and as a nematicide. It is used on different crops, ranging from potatoes, bananas, and sugarcane to ornamental plants and tobacco. [1] Most of the ethoprop used in the United States is applied to potatoes. In the period of 1987 to 1996, an estimated total of 691,000 pounds (313,400 kg) of the pesticide were used on field crops and vegetables. [5]
When an organism is exposed to ethoprophos either via the oral, dermal or inhalation routes, it primarily inhibits carboxyl ester hydrolases, specifically acetylcholinesterase (AChE). This enzyme is important in degradation of the neurotransmitter acetylcholine (ACh). Inactivation of AChE takes place by phosphorylation of serine hydroxyl group at the active site of AChE. Later, phosphorylation is followed by one of the following scenarios: [6]
When AChE is inactivated, ACh accumulates in the nervous system, which then results in overstimulation of muscarinic and nicotinic receptors. [6]
Another target of ethoprophos is erythrocyte acetylcholinesterase. The only known location of this enzyme is on the outside of erythrocyte membranes. However, physiological functions of this AChE type are not completely known. [7]
In cases of exposure to ethoprophos, symptoms may include vomiting, nausea, diarrhea, miosis, abdominal cramps, dyspnoea, muscular weakness, bronchial hypersecretion, anxiety, confusion and convulsions. In case of ethoprophos poisoning, a combination of atropine and pralidoxime (2-PAM) is the most effective antidote. [1]
Additionally, ethoprophos is thought to be likely carcinogenic due to the occurrence of different types of tumors in rats after exposure to the compound. Dietary exposure (the most common route of exposure to ethoprophos) is so low, however, that there is a low risk for the general U.S. population. [5]
In mammals, metabolism usually proceeds by removal of one or both of the propyl groups and subsequent conjugation. In rats, metabolism is independent of sex, dose, route of administration, or repeated administration, and no parent compound is detectable in faeces or urine. The main metabolite in humans is EPPA, shown below, which can be used as a biomarker for ethoprophos. The dealkylated metabolites have similar toxic effects to the parent compound. [1]
In tested animals, ethoprophos is widely distributed throughout the body, with the highest concentrations in the lungs, kidneys, and liver. In blood, it is mostly associated to cells instead of being in the plasma. Excretion mainly proceeds through the urine (~60%), but faecal excretion (~10%) and expired air (~15%) are also important routes. Intravenously dosed animals showed limited biliary excretion (~8%). [1]
Experiments carried out on ethoprophos have shown that the toxin affects animals in various manners. Short-term toxicity effects in rabbits and mice, exposed through different routes include inhibition of erythrocyte and brain cholinesterase. While experiments on dogs gave rise to cellular vacuolisation as well. [1] Acute toxicity studies on rats, in turn have resulted in more effects being observed, namely narcotic, cholinergic and respiratory. The latter was shown to be expressed after a delay of 4 days and linked to an increase in lung weight. [8] Studies carried out with extended exposure of ethoprophos in mice gave the same results as research on short-term exposure had, but in rats a fall in hemoglobin concentrations was also observed. [1] On the other hand, a long-term exposure experiment conducted on dogs found that the toxin led to mild liver toxicity. [5]
Furthermore, exposure to ethoprophos was found to affect reproduction as well. Parental toxicity in rats resulted in a drop in their body weight and food consumption. Moreover, abortion cases increased, leading to a reduction of litter sizes. On the other hand, offspring toxicity led to a decrease in body weight gain and rise in postnatal mortality. [1]
Ethoprophos is considered to pose a low risk to mammals exposed to contaminated water as well as mammals feeding on contaminated fish. It is, however, extremely toxic to bees under direct exposure and also to birds which are exposed to the toxin through dietary routes. These involve ingestion of seeds or worms including residues of contaminated soil. [1] Finally, a study showed that ethoprophos, along with 4 other active substances, was responsible for 40% of the utilized pesticides in Costa Rica, yet they contributed to more than three quarters of the aquatic toxicity. [9] Thus, it has also been concluded to be highly toxic to aquatic species. [1]
When orally exposed to ethoprophos, absorption is fast and extensive: the time it takes to reach peak blood levels is below 1 hour and more than 90% of the substance is absorbed. [6] Short-term dermal exposure to liquid ethoprophos was tested in rabbits in a 21 day long study. The dermal NOAEL was 0.1 mg/kg/day and the researchers found that there was acetylcholinesterase inhibition in plasma, erythrocytes and in the brain at a dose of 1.0 mg/kg/day. The short-term dermal exposure to granular ethoprophos was also studied. This study was conducted with rats and lasted for 28 days. In this case, a dermal NOAEL of 20 mg/kg/day was found. Acetylcholinesterase inhibition in plasma happened at a dose of 100 mg/kg/day. For short-term inhalation, a study was done with dogs and it lasted for 90 days. The results showed a NOAEL of 0.025 mg/kg/day and the acetylcholinesterase inhibition in plasma occurred at a dose of 0.075 mg/kg/day. No information about intermediate and long term exposure via dermal and inhalation routes is known at this moment. When rats were chronically exposed to ethoprophos with a dose of 2.81 x 10^-2 mg/kg/day, a number of rats developed malignant adrenal pheochromocytomas. For granular products, inhalation exposure is considered to be the main risk. In the case of liquid products dermal exposure is considered to be the main risk. [5]
Soman is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiting the enzyme cholinesterase. It is an inhibitor of both acetylcholinesterase and butyrylcholinesterase. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN Resolution 687. Its production is strictly controlled, and stockpiling is outlawed by the Chemical Weapons Convention of 1993 where it is classified as a Schedule 1 substance. Soman was the third of the so-called G-series nerve agents to be discovered along with GA (tabun), GB (sarin), and GF (cyclosarin).
A reference dose is the United States Environmental Protection Agency's maximum acceptable oral dose of a toxic substance, "below which no adverse noncancer health effects should result from a lifetime of exposure". Reference doses have been most commonly determined for pesticides. The EPA defines an oral reference dose as:
[A]n estimate, with uncertainty spanning perhaps an order of magnitude, of a daily oral exposure to the human population that is likely to be without an appreciable risk of deleterious effects during a lifetime.
Chlorfenvinphos is the common name of 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.
Ethion (C9H22O4P2S4) is an organophosphate insecticide. Ethion is known to affect a neural enzyme called acetylcholinesterase and prevent it from working.
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.
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.
Patulin is an organic compound classified as a polyketide. It is a white powder soluble in acidic water and in organic solvents. It is a lactone that is heat-stable, so it is not destroyed by pasteurization or thermal denaturation. However, stability following fermentation is lessened. It is a mycotoxin produced by a variety of molds, in particular, Aspergillus and Penicillium and Byssochlamys. Most commonly found in rotting apples, the amount of patulin in apple products is generally viewed as a measure of the quality of the apples used in production. In addition, patulin has been found in other foods such as grains, fruits, and vegetables. It's presence is highly regulated.
1,1,2,2-tetrachloroethane (TeCA), also known as bonoform, cellon, or westron is an organic compound. It is colorless liquid and has a sweet odor. It is used as an industrial solvent or as a separation agent. TeCA is toxic and it can be inhaled, consumed or absorbed through the skin. After exposure, nausea, dizziness or even liver damage may occur.
Organophosphate poisoning is poisoning due to organophosphates (OPs). Organophosphates are used as insecticides, medications, and nerve agents. Symptoms include increased saliva and tear production, diarrhea, vomiting, small pupils, sweating, muscle tremors, and confusion. While onset of symptoms is often within minutes to hours, some symptoms can take weeks to appear. Symptoms can last for days to weeks.
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.
Chlorethoxyfos is an organophosphate acetylcholinesterase inhibitor used as an insecticide. It is registered for the control of corn rootworms, wireworms, cutworms, seed corn maggot, white grubs and symphylans on corn. The insecticide is sold under the trade name Fortress by E.I. du Pont de Nemours & Company.
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.
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.
Sulfotep (also known as tetraethyldithiopyrophosphate and TEDP) 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. 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. It is primarily used as an insecticide.
Terbufos is a chemical compound used in insecticides and nematicides. Terbufos 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.
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.
Triazofos is a chemical compound used in acaricides, insecticides, and nematicides.
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.
Novaluron, or (±)-1-[3-chloro-4-(1,1,2-trifluoro-2-trifluoro- methoxyethoxy)phenyl]-3-(2,6-difluorobenzoyl)urea, is a chemical with pesticide properties, belonging to the class of insecticides called insect growth regulators. It is a benzoylphenyl urea developed by Makhteshim-Agan Industries Ltd.. In the United States, the compound has been used on food crops, including apples, potatoes, brassicas, ornamentals, and cotton. Patents and registrations have been approved or are ongoing in several other countries throughout Europe, Asia, Africa, South America, and Australia. The US Environmental Protection Agency and the Canadian Pest Management Regulatory Agency consider novaluron to pose low risk to the environment and non-target organisms and value it as an important option for integrated pest management that should decrease reliance on organophosphorus, carbamate and pyrethroid insecticides.
Cadusafos is a chemical insecticide and nematicide often used against parasitic nematode populations. The compound acts as a acetylcholinesterase inhibitor. It belongs the chemical class of synthetic organic thiosulfates and it is a volatile and persistent clear liquid. It is used on food crops such as tomatoes, bananas and chickpeas. It is currently not approved by the European Commission for use in the EU. Exposure can occur through inhalation, ingestion or contact with the skin. The compound is highly toxic to nematodes, earthworms and birds but poses no carcinogenic risk to humans.