Dichlorvos

H301: Toxic if swallowed [Danger Acute toxicity, oral]

H311: Toxic in contact with skin [Danger Acute toxicity, dermal]

H317: May cause an allergic skin reaction [Warning Sensitization, Skin]

H330: Fatal if inhaled [Danger Acute toxicity, inhalation]

H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

P260, P261, P262, P264, P270, P271, P272, P273, P280, P284, P301+P316, P302+P352, P304+P340, P316, P320, P321, P330, P333+P317, P361+P364, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

H300 (52.7%): Fatal if swallowed [Danger Acute toxicity, oral]

H301 (47.3%): Toxic if swallowed [Danger Acute toxicity, oral]

H311 (92%): Toxic in contact with skin [Danger Acute toxicity, dermal]

H317 (100%): May cause an allergic skin reaction [Warning Sensitization, Skin]

H330 (53.6%): Fatal if inhaled [Danger Acute toxicity, inhalation]

H331 (46.4%): Toxic if inhaled [Danger Acute toxicity, inhalation]

H400 (100%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

Aggregated GHS information provided per 112 reports by companies from 7 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H350: May cause cancer [Danger Carcinogenicity]

P203, P280, P318, P405, and P501 (click each P-code to see the statement)

H310: Fatal in contact with skin [Danger Acute toxicity, dermal]

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H320: Causes eye irritation [Warning Serious eye damage/eye irritation]

H351: Suspected of causing cancer [Warning Carcinogenicity]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

H410: Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P203, P260, P261, P262, P264, P264+P265, P270, P271, P272, P273, P280, P284, P301+P316, P302+P352, P304+P340, P305+P351+P338, P308+P316, P316, P318, P319, P320, P321, P330, P332+P317, P333+P317, P337+P317, P361+P364, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

H316: Causes mild skin irritation [Warning Skin corrosion/irritation]

H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

P260, P261, P262, P264, P264+P265, P270, P271, P272, P280, P284, P301+P316, P302+P352, P304+P340, P305+P351+P338, P308+P316, P316, P319, P320, P321, P330, P332+P317, P333+P317, P337+P317, P361+P364, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

H300: Fatal if swallowed [Danger Acute toxicity, oral]

P203, P260, P261, P262, P264, P270, P271, P272, P273, P280, P284, P301+P316, P302+P352, P304+P340, P316, P318, P320, P321, P330, P333+P317, P361+P364, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Fresh air, rest. Refer immediately for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer immediately for medical attention.

Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Refer immediately for medical attention.

Warning: Effects may be delayed up to 12 hours. Caution is advised.

Note: Dichlorvos is a cholinesterase inhibitor.

Signs and Symptoms of Acute Dichlorvos Exposure: Acute exposure to dichlorvos may produce the following signs and symptoms: sweating, pinpoint pupils, blurred vision, headache, dizziness, profound weakness, muscle spasms, seizures, and coma. Mental confusion and psychosis may occur. Excessive salivation, nausea, vomiting, anorexia, diarrhea, and abdominal pain may also occur. The heart rate may decrease following oral exposure or increase following dermal exposure. Chest pain may be noted. Hypotension (low blood pressure) may be observed, although hypertension (high blood pressure) is not uncommon. Respiratory symptoms include dyspnea (shortness of breath), pulmonary edema, respiratory depression, and respiratory paralysis.

Emergency Life-Support Procedures: Acute exposure to dichlorvos may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.

Inhalation Exposure:

1. Move victims to fresh air. Emergency personnel should avoid self-exposure to dichlorvos.

2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support.

3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.

4. Transport to a health care facility.

Dermal/Eye Exposure:

1. Remove victims from exposure. Emergency personnel should avoid self-exposure to dichlorvos.

3. Remove contaminated clothing as soon as possible.

4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.

5. Wash exposed skin areas three times with soap and water.

6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.

7. Transport to a health care facility.

Ingestion Exposure:

1. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support.

2. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.

3. Vomiting may be induced with syrup of Ipecac. If elapsed time since ingestion of dichlorvos is unknown or suspected to be greater than 30 minutes, do not induce vomiting and proceed to Step

4. Ipecac should not be administered to children under 6 months of age.Warning: Ingestion of dichlorvos may result in sudden onset of seizures or loss of consciousness. Syrup of Ipecac should be administered only if victims are alert, have an active gag-reflex, and show no signs of impending seizure or coma. If ANY uncertainty exists, proceed to Step

4.The following dosages of Ipecac are recommended: children up to 1 year old, 10 mL (1/3 oz); children 1 to 12 years old, 15 mL (1/2 oz); adults, 30 mL (1 oz). Ambulate (walk) the victims and give large quantities of water. If vomiting has not occurred after 15 minutes, Ipecac may be readministered. Continue to ambulate and give water to the victims. If vomiting has not occurred within 15 minutes after second administration of Ipecac, administer activated charcoal.

4. Activated charcoal may be administered if victims are conscious and alert. Use 15 to 30 g (1/2 to 1 oz) for children, 50 to 100 g (1-3/4 to 3-1/2 oz) for adults, with 125 to 250 mL (1/2 to 1 cup) of water.

5. Promote excretion by administering a saline cathartic or sorbitol to conscious and alert victims. Children require 15 to 30 g (1/2 to 1 oz) of cathartic; 50 to 100 g (1-3/4 to 3- 1/2 oz) is recommended for adults.

6. Transport to a health care facility. (EPA, 1998)

(General first aid procedures)

Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: Soap wash immediately - If this chemical contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly.

Breathing: Respiratory support

Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

Use self-contained breathing apparatus with a full face piece operated on pressure-demand or other positive pressure mode. Prevent skin contact with protective clothing. Isolate area and deny entry. Fight fire from maximum distance. Dike fire control water for future disposal.

Use water in flooding quantities as fog, alcohol foam, dry chemical, or carbon dioxide. Do not scatter the material. (EPA, 1998)

Use water spray, foam, powder, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.

Use dry chemical, carbon dioxide, or foam extinguishers. Use self-contained breathing apparatus with a full face-piece operated on pressure-demand or other positive-pressure mode. Prevent skin contact with protective clothing. Isolate area and deny entry. Fight fire from maximum distance. Dike fire control water for future disposal. ... If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Notify local health and fire officials and pollution control agencies. From a secure, explosion-proof location, use water spray to cool exposed containers. If cooling streams are ineffective (venting sound increases in volume and pitch, tank discolors, or shows any signs of deforming), withdraw immediately to a secure position. ... The only respirators recommended for firefighting are self-contained breathing apparatuses that have full face-pieces and are operated in a pressure-demand or other positive-pressure mode.

Do not use water; smother with foam, /carbon dioxide/, dry.

For more Fire Fighting Procedures (Complete) data for Dichlorvos (6 total), please visit the HSDB record page.

Vapors are heavier than air and will collect in low areas. Vapors in confined areas may explode when exposed to fire. Containers may explode in fire. Storage containers and parts of containers may rocket great distances, in many directions.

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Evacuate danger area! Consult an expert! Personal protection: chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Do NOT wash away into sewer. Ventilation. Collect leaking liquid in sealable containers. Absorb liquid in sand or inert absorbent. Then store and dispose of according to local regulations.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Methods and materials for containment and cleaning up: Soak up with inert absorbent material and dispose of as hazardous waste. Keep in suitable, closed containers for disposal.

Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Ventilate area of spill or leak. Remove and isolate contaminated clothing at the site. Do not touch spilled material; stop leaks if you can do it without risk. Reduce vapors with water spray. Take up small spills with sand or other noncombustible absorbent material for later disposal in canisters. Dike large spills far ahead of spill for later disposal. Keep this chemical out of a confined space, such as a sewer, because of the possibility of an explosion, unless the sewer is designed to prevent the buildup of explosive concentrations. It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters.

Environmental consideration: Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash, or cement powder.

Environmental considerations: Water spill: If dissolved in region of 10 ppm or greater concentration, apply activated carbon at ten times the spilled amount. ...

For more Cleanup Methods (Complete) data for Dichlorvos (7 total), please visit the HSDB record page.

SRP: 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 air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber; Contaminated packaging: Dispose of as unused product.

Fifty percent hydrolysis is obtained in pure water in 25 min at 70 °C and in 61.5 days at 20 °C. A buffered solution yields 50% hydrolysis (37.5 °C) in 301 min at pH 8, 462 min at pH 7, 620 min at pH 5.4. Hydrolysis yields no toxic residues. Incineration in a furnace equipped with an afterburner and alkaline scrubber is recommended as is alkaline hydrolysis followed by soil burial. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency or by contacting your regional EPA office.

For more Disposal Methods (Complete) data for Dichlorvos (11 total), please visit the HSDB record page.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.

Precautions for safe handling: Avoid contact with skin and eyes. Avoid inhalation of vapor or mist.

Appropriate engineering controls: Avoid contact with skin, eyes and clothing. Wash hands before breaks and immediately after handling the product.

Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.

For more Preventive Measures (Complete) data for Dichlorvos (25 total), please visit the HSDB record page.

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2024)

Store only in original container. Well closed. Keep in a well-ventilated room. Provision to contain effluent from fire extinguishing. Separated from food and feedstuffs. Store in an area without drain or sewer access.

Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Recommended storage temperature -20 °C.

Store in a secure poison location. ... Store in tightly closed containers in a cool, well-ventilated area away from strong acids; strong alkalis. Dichlorvos will attack some forms of mild iron, plastics, rubber, and coatings.

Store in tightly sealed container, protected from light, and at room temperature. Stability of compounded formulations has not been evaluated.

Store Atgard swine wormer at less than 80 °F. Dichlorvos feed additives should not be stored at temperatures below freezing. Dichlorvos is sensitive to hydrolysis if exposed to moisture or oxidizing agents.

PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practical to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/

Biological Exposure Indices (BEI) [ACGIH] - Acetylcholinesterase activity in red blood cells = 70% of individual's baseline; Butylcholinesterase activity in serum or plasma = 60% of individual's baseline; Sample at end of shift; [TLVs and BEIs]

1.0 [mg/m3]

AEGL 1: Notable discomfort, irritation, or certain asymptomatic non-sensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure (Unit: ppm)

AEGL 2: Irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape (Unit: ppm)

AEGL 3: Life-threatening health effects or death (Unit: ppm)

Technical Support Document in preparation. Please check back later.

AEGLs Status: Proposed

2.0 [mg/m3]

20 [mg/m3]

200 [mg/m3]

TWA 1 mg/m3 [skin]

100 mg/m3 (NIOSH, 2024)

100.0 [mg/m3]

100 mg/cu m

100 mg/m³

100 mg/m3

See: 62737

0.1 [mg/m3], inhalable fraction and vapor

8 hr Time Weighted Avg (TWA): 0.1 mg/cu m, inhalable fraction and vapor, skin, dermal sensitization

Peak Exposure Recommendation: Transient increases in workers' exposure levels may exceed 3 times the value of the TLV-TWA level for no more than 15 minutes at a time, on no more than 4 occasions spaced 1 hour apart during a workday, and under no circumstances should they exceed 5 times the value of the TLV-TWA level. In addition, the 8-hour TWA is not to be exceeded for an 8-hour work period.

A4; Not classifiable as a human carcinogen.

Biological Exposure Index (BEI): Determinant: Cholinesterase activity in red blood cells; Sampling Time: Discretionary; BEI: 70% of individual's baseline. The determinant is nonspecific, since it is also observed after exposure to other chemicals. /Acetylcholinesterase Inhibiting Pesticides/

2017 Notice of Intended Changes (NIC): These substances, with their corresponding indices, comprise those for which (1) a BEI is proposed for the first time, (2) a change in the Adopted index is proposed, (3) retention as an NIC is proposed, or (4) withdrawal of the Documentation and adopted BEI is proposed. In each case, the proposals should be considered trial indices during the period they are on the NIC. These proposals were ratified by the ACGIH Board of Directors and will remain on the NIC for approximately one year following this ratification. If the Committee neither finds nor receives any substantive data that change its scientific opinion regarding an NIC BEI, the Committee may then approve its recommendation to the ACGIH Board of Directors for adoption. If the Committee finds or receives substantive data that change its scientific opinion regarding an NIC BEI, the Committee may change its recommendation to the ACGIH Board of Directors for the matter to be either retained on or withdrawn from the NIC. Chemical: Cholinesterase Inhibiting Pesticides. /Cholinesterase Inhibiting Pesticides/

Table: Cholinesterase Inhibiting Pesticides [Table#1043]

0.1 mg/m

0.1 mg/m³ (inhalable fraction and vapor) [1998]

Australia: 0.1 ppm, skin (1990); Federal Republic of Germany: 0.1 ppm, short-term level 1 ppm, 30 min, once per shift, skin, Pregnancy group C, no reason to fear a risk of damage to the developing embryo or fetus when MAK and BAT values are adhered to (1990); United Kingdom: 0.1 ppm, 10-min STEl 0.3 ppm, skin (1991)

A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20 °C , on spraying or dispersing much faster.

The substance is irritating to the skin. The substance may cause effects on the nervous system by a cholinesterase inhibiting effect. Exposure above the OEL could cause death. The effects may be delayed. Medical observation is indicated.

Repeated or prolonged contact with skin may cause dermatitis. Repeated or prolonged contact may cause skin sensitization. Cholinesterase inhibition. Cumulative effects are possible. See Acute Hazards/Symptoms. This substance is possibly carcinogenic to humans.

A tolerance of 0.1 part per million is established for negligible residues of dichlorvos (2,2-dichlorovinyl dimethyl phosphate) in the edible tissues of swine.

Excerpt from NIOSH Pocket Guide for Dichlorvos:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift. (NIOSH, 2024)

Eye/face protection: Face shield and safety glasses. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).

Skin protection: Handle with gloves.

Body Protection: Complete suit protecting against chemicals. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.

Dichlorvos appears as a colorless to amber liquid with an aromatic odor. When heated to high temperatures may emit toxic chloride fumes and phosgene gas. Toxic by inhalation, skin absorption or ingestion. Used as a pesticide. May be found in the form of a dry mixture where the liquid is absorbed onto a dry carrier.

Colorless to amber liquid with a mild, chemical odor. [NIOSH]

COLOURLESS-TO-AMBER LIQUID WITH CHARACTERISTIC ODOUR.

Colorless to amber liquid with a mild, chemical odor.

Colorless to amber liquid with a mild, chemical odor. [Note: Insecticide that may be absorbed on a dry carrier.]

Colorless liquid

Colorless to amber liquid [Note: Insecticide that may be absorbed on a dry carrier]

Aromatic odor

Mild, chemical odor

284 °F at 20 mmHg (EPA, 1998)

234.1 °C at 750 mm Hg

BP: 140 °C at 20 mm Hg; 84 °C at 1.0 mm Hg; 72 °C at 0.5 mm Hg; 30 °C at 0.01 mm Hg

at 101.3kPa: 234 °C

284 °F at 20 mmHg

Decomposes

183 °F (NTP, 1992)

Less than -60 °C

Greater than 175F (EPA, 1998)

100 °C (212 °F) - closed cup

350 °F (177 °C) - open cup

10 to 50 mg/mL at 68 °F (NTP, 1992)

In water, 8.00X10+3 mg/L at 20 °C

In water, about 1g/100 mL

Slightly soluble in glycerin; miscible with aromatic and chlorinated hydrocarbon solvents and alcohols.

Miscible in dichloromethane, 2-propanol, toluene. Barely soluble in kerosene.

For more Solubility (Complete) data for Dichlorvos (6 total), please visit the HSDB record page.

8 mg/mL at 20 °C

Solubility in water, g/l at 20 °C: 10 (poor)

1.415 at 77 °F (EPA, 1998) - Denser than water; will sink

1.415 g/cu cm at 25 °C/D

Relative density (water = 1): 1.4

1.42 @25 °C

(77 °F): 1.42

Relative vapor density (air = 1): 7.6

0.01 mmHg at 86 °F (EPA, 1998)

0.01 [mmHg]

1.58X10-2 mm Hg at 25 °C

Vapor pressure, Pa at 20 °C: 1.6

0.01 mmHg

log Kow = 1.43

More dense than water and slightly soluble in water.

Esters, Sulfate Esters, Phosphate Esters, Thiophosphate Esters, and Borate Esters

Halogenated Organic Compounds

Hydrocarbons, Aliphatic Unsaturated

DICHLORVOS is incompatible with strong acids and bases. It is slowly hydrolyzed in acidic media and rapidly hydrolyzed by alkalis. It is corrosive to iron and mild steel. (NTP, 1992). Organophosphates are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides.

Contact with oxidizers may cause the release of phosphorous oxides. Contact with strong reducing agents, such as hydrides, may cause the formation of flammable and toxic phosphine gas. Corrosive to iron, mild steel, some forms of plastics, rubber, and coatings.

Strong acids, strong alkalis [Note: Corrosive to iron & mild steel].

Strong acids, strong alkalis [Note: Corrosive to iron & mild steel.]

CDC-ATSDR Toxicological Profile

IDENTIFICATION AND USE: Dichlorvos is a colorless to amber liquid. It is a contact and stomach insecticide with fumigant and penetrant action, which is used as household and public health fumigant. Dichlorvos as a "No Pest Strip" is used as an ectoparasiticide for small mammals. It is also used as a premise spray to keep fly populations controlled. HUMAN STUDIES: Potential symptoms of overexposure are miosis, aching eyes, rhinorrhea, headache, chest tightening, wheezing, laryngeal spasms and salivation, cyanosis, anorexia, nausea, vomiting and diarrhea, sweating, muscle fasciculation, paralysis, giddiness and ataxia, convulsions, low blood pressure, cardiac irregularities, and irritation of eyes and skin. Red blood cell (RBC) acetylcholinesterase activity was reduced in some residents exposed to an estimated level of 0.2 mg/cu m dichlorvos for about 15.8 hr, and some residents complained of headache. Suicide attempts with dichlorvos have been described. Several cases of delayed extrapyramidal disorder described after acute dichlorvos poisonings. Dichlorvos did not cause sister chromatid exchange in vitro in human cells. ANIMAL STUDIES: In a guinea pig maximization test, induction with dichlorvos by intradermal injection and topical application and subsequent challenge with topical dichlorvos solutions showed sensitization. When rats were given single oral doses of 0.5, 35, or 70 mg/kg dichlorvos by gavage, the 35- and 70-mg/kg groups exhibited cholinergic signs within 15 min after dosing. Several animals in the 70-mg/kg group died. A saturated atmosphere of dichlorvos (230-341 mg/cu m) caused deaths in rats after 7 to 62 hr. RBC cholinesterase was inhibited in monkeys exposed to 12.9 mg/cu m. Cholinergic signs occurred within 7-15 min in dogs given a single oral dose of 11 or 22 mg/kg dichlorvos. Three of 12 dogs given 22 mg/kg died within 10-155 min of treatment. Three cynomolgus monkeys were given daily dermal doses of dichlorvos in xylene on a shaved area between the shoulder blades. A monkey receiving 100 mg/kg/day died after 4 days. A monkey given 50 mg/kg/day died after 8 doses over 10 days and a monkey given 75 mg/kg/day died after 10 doses over 12 days. Clinical signs in their order of appearance were nervousness, gritting of teeth, incoordination, muscle fasciculations, excessive salivation, labored breathing, miosis, and flaccidity. 90-day studies of dichlorvos in rats have shown that dietary levels up to 70 mg/kg/day do not result in overt cholinergic toxicity, although exposures inhibit RBC cholinesterase. Rabbits are more sensitive than rats or mice to dichlorvos vapor. Carcinogenicity was not reported in male or female mice given 58 or 95 mg/kg/day or 56 or 102 mg/kg/day, respectively, in their drinking water for 2 yr. No adverse effect occurred on fetuses when pregnant rabbits were administered doses of 0.1 to 7.0 mg/kg/day dichlorvos by gavage on gestation days 7 through 19 or when rabbits were exposed for 23 hr/day to 0.25 to 6.25 mg/ cu m dichlorvos vapor on gestation days 1 through 28. When dichlorvos (15 mg/kg/day) was administered to guinea pigs between day 42 and 46 of gestation, offspring exhibited severe reductions in brain weight. In a 3-generation reproduction study in weanling rats no effects on fertility, number and size of litters, body weight, or viability of the pups were found. Dichlorvos was a mutagen in the screening test for mutagenicity using a REC-assay procedure, with H17 REC(+) and M45 REC(-) strains of Bacillus subtilis and reversion assays on auxotrophic strains of Escherichia coli (WP2) and Salmonella typhimurium (Ames series). Dichlorvos increased the frequency of chromosomal damage and micronucleus formation in Chinese hamster ovary cells; induced sister chromatid exchange, chromosomal aberrations, and transformation in cultured rat tracheal epithelial cells; induced DNA single-strand breaks in isolated rat hepatocytes; and caused increases in cell transformation of hamster embryo cells. It was negative in the sex-linked lethal mutation test in Drosophila. ECOTOXICITY STUDIES: In mallards and pheasants the symptoms of acute oral toxicity included: goose-stepping ataxia, use of wings to aid in balance, tremors, convulsions. Various internal hemorrhages were found at autopsy in sacrificed survivors of both species. Exposure of white-footed mice to pelleted dichlorvos caused 3%, 20%, and 53% mortality in mice exposed to 1, 3, and 6 g dichlorvos per cage. Iberian toothcarp was able to tolerate high concentrations of dichlorvos, and resist high levels of brain and muscle ChE inhibition without mortality. Dichlorvos is not toxic to mussels or periwinkles at 1.0 ppm, for 1 hr exposure, but is toxic to larval lobsters, adult lobsters, zooplankton and phytoplankton. It was also toxic to bees.

Dichlorvos is a cholinesterase or acetylcholinesterase (AChE) inhibitor. A cholinesterase inhibitor (or 'anticholinesterase') suppresses the action of acetylcholinesterase. Because of its essential function, chemicals that interfere with the action of acetylcholinesterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death. Nerve gases and many substances used in insecticides have been shown to act by binding a serine in the active site of acetylcholine esterase, inhibiting the enzyme completely. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop. Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds, which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate), and a terminal oxygen.

Dichlorvos

Endocrine

Gastrointestinal

Hematologic

5 x 10 ^-4 mg/kg-day

5 x 10 ^-4 mg/m^3

Pesticide and(or) Waste-water effluent contaminant

Smith, C.D. and Nowell, L.H., 2024. Health-Based Screening Levels for evaluating water-quality data (3rd ed.). DOI:10.5066/F71C1TWP

Cancer Classification: Suggestive Evidence of Carcinogenicity, but Not Sufficient to Assess Human Carcinogenic Potential

Evaluation: There is inadequate evidence in humans for the carcinogenicity of dichlorvos. There is sufficient evidence in experimental animals for the carcinogenicity of dichlorvos. Overall evaluation: Dichlorvos is possibly carcinogenic to humans (2B).

A4; Not classifiable as a human carcinogen.

Group 2B: Possibly carcinogenic to humans

Volume Sup 7: Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42, 1987; 440 pages; ISBN 92-832-1411-0 (out of print)

Volume 53: (1991) Occupational Exposures in Insecticide Application, and Some Pesticides

TR-342: Toxicology and Carcinogenesis Studies of Dichlorvos (CASRN 62-73-7) in F344/N Rats and B6C3F1 Mice (Gavage Studies) (1989 )

07/14/87

Some Evidence

Equivocal Evidence

Clear Evidence

Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity of dichlorvos for male F344/N rats, as shown by increased incidences of adenomas of the exocrine pancreas and mononuclear cell leukemia. There was equivocal evidence of carcinogenic activity of dichlorvos for female F344/N rats, as shown by increased incidences of adenomas of the exocrine pancreas and mammary gland fibroadenomas. There was some evidence of carcinogenic activity of dichlorvos for male B6C3F1 mice, as shown by increased incidences of forestomach squamous cell papillomas. There was clear evidence of carcinogenic activity of dichlorvos for female B6C3F1 mice, as shown by increased incidences of forestomach squamous cell papillomas.

TR-010: Bioassay of Dichlorvos for Possible Carcinogenicity (CASRN 62-73-7) (1977 )

09/01/76

No Evidence

After the doses were reduced, no toxic signs directlyattributable to the compound were observed. However, average weights of high-dose animals were slightly depressed. Survival was not dose-related in either species. Microscopic study of the tissues of treated animals and matched and pooled controls revealed no statistically significant increase in the incidence of tumors attributable to exposure to dichlorvos in either animal species. The significance of the three esophageal tumors in male and female mice and of malignant fibrous histiocytomas in male mice is unclear and there is insufficient evidence to indicate they were associated with dichlorvos treatment. Thus under the conditions of this study, dichlorvos was not demonstrated to be carcinogenic.

2B, possibly carcinogenic to humans. (L135)

Acute exposure to cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. When there is an accumulation of ACh at autonomic ganglia this causes overstimulation of nicotinic expression in the sympathetic system. Symptoms associated with this are hypertension, and hypoglycemia. Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur. Certain reproductive effects in fertility, growth, and development for males and females have been linked specifically to organophosphate pesticide exposure. Most of the research on reproductive effects has been conducted on farmers working with pesticides and insecticdes in rural areas. In females menstrual cycle disturbances, longer pregnancies, spontaneous abortions, stillbirths, and some developmental effects in offspring have been linked to organophosphate pesticide exposure. Prenatal exposure has been linked to impaired fetal growth and development. Neurotoxic effects have also been linked to poisoning with OP pesticides causing four neurotoxic effects in humans: cholinergic syndrome, intermediate syndrome, organophosphate-induced delayed polyneuropathy (OPIDP), and chronic organophosphate-induced neuropsychiatric disorder (COPIND). These syndromes result after acute and chronic exposure to OP pesticides.

The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

inhalation, skin absorption, ingestion, skin and/or eye contact

Oral (L1171) ; inhalation (L1171) ; dermal (L1171)

Pupillary constriction, muscle cramp, excessive salivation. Muscle twitching. Convulsions. Dizziness. Sweating. Wheezing. Laboured breathing. Unconsciousness.

MAY BE ABSORBED! Redness. Further see Inhalation.

Redness. Pain. Pupillary constriction. Blurred vision.

Excessive salivation. Nausea. Vomiting. Abdominal cramps. Diarrhoea. Further see Inhalation.

irritation eyes, skin; miosis, ache eyes; rhinorrhea (discharge of thin nasal mucus); headache; chest tightness, wheezing, laryngeal spasm, salivation; cyanosis; anorexia, nausea, vomiting, diarrhea; sweating; muscle fasciculation, paralysis, dizziness, ataxia; convulsions; low blood pressure, cardiac irreg

The effects of organophosphate poisoning are recalled using the mnemonic SLUDGEM (Salivation, Lacrimation, Urination, Diaphoresis (or Defecation), Gastrointestinal motility, Emesis, Miosis). (L1168)

Cancer, Gastrointestinal (Stomach and Intestines, part of the digestive system), Neurological (Nervous System)

Eyes, skin, respiratory system, cardiovascular system, central nervous system, blood cholinesterase

LC50; Species: /Pimephales promelas/ (Fathead minnow) weight 0.7 g; Conditions: static bioassay, 17 °C; Concentration: 11,600 ug/L for 96 hr (95% confidence limit: 7,830-17,200 ug/L) /Technical material, 93%/

LC50; Species: /Lepomis macrochirus/ (Bluegill) weight 1.5 g; Conditions: static bioassay, 18 °C; Concentration: 869 ug/L for 96 hr (95% confidence limit: 700-1,080 ug/L) /Technical material, 100%/

LC50; Species: /Gambusia affinis/ (Mosquitofish) weight 0.2 g; Conditions: static bioassay, 17 °C; Concentration: 5,270 ug/L for 96 hr (95% confidence limit: 2,660-10,400 ug/L) /Technical material, 100%/

LC50; Species: /Oncorhynchus clarki/ (Cutthroat trout) weight 2.5 g; Conditions: static bioassay, 12 °C; Concentration: 170 ug/L for 96 hr (95% confidence limit: 143-203 ug/L) /Technical material, 100%/

For more Ecotoxicity Values (Complete) data for Dichlorvos (80 total), please visit the HSDB record page.

/BIRDS and MAMMALS/ /In mallards and pheasants/, the symptomology /(acute oral toxicity)/ included: Goose-stepping ataxia, use of wings to aid in balance, tremors, convulsions. Various internal hemorrhages were found at autopsy in sacrificed survivors of both species.

/BIRDS and MAMMALS/ Exposure of white-footed mice and laboratory mice to pelleted dichlorvos (an /organophosphate/ commonly used for control of ectoparasites) did not affect survival of laboratory mice, but did result in 3%, 20%, and 53% mortality in white-footed mice exposed to 1, 3, and 6 g dichlorvos per cage.

/AQUATIC SPECIES/ This study evaluates the toxic effects of the organophosphate pesticide (OP) dichlorvos to the endangered Iberian toothcarp (Aphanius iberus). To this end, the lethal toxicity of dichlorvos based on 96 hr-LC50 bioassays was determined in saline water (50 g/L), and in vivo effects of dichlorvos on cholinesterase (ChE) activity were investigated in adult female and male specimens. The 96 hr-LC50 value determined by probit analysis was 3.17 mg/L (95% confidence limits: 1.34-3.97). The characterisation of the ChE using different substrates and specific inhibitors was also carried out in head and muscle tissues. Acetylthiocholine was the substrate preferred by both head and muscle ChE in males and females. Eserine sulphate and BW284C51 significantly inhibited both head and muscle enzyme activity at low concentrations (uM range), and iso-OMPA had no significant effect. These results indicate that in the head and muscle the predominant ChE form is acetylcholinesterase (AChE) for both sexes. The kinetic parameters for ChE activity (Km and Vmax) were similar in both sexes. The 96 hr-LC50 value obtained for adult specimens of Iberian toothcarp was 3.17 mg/L. ChE activity in head and body tissues of both sexes was significantly inhibited in all concentrations tested (0.5, 1, 2 and 4 mg/L) after "in vivo" dichlorvos exposure. However, Iberian toothcarp was able to tolerate high concentrations of dichlorvos, and resist high levels of brain and muscle ChE inhibition without mortality. Both ChE inhibition and recovery followed a similar time-course pattern in response to sub-lethal exposure to dichlorvos (1 mg/L), and the enzyme activity did not return to control levels after 96 hr in clean water. The results of this study show that ChE activity is a good biomarker of exposure to OP in the Iberian toothcarp adults.

/AQUATIC SPECIES/ Acetylcholinesterase (AChE) activity has been used to test the exposure of mollusk bivalves to pesticides and other pollutants. The Pacific oyster Crassostrea gigas is a species with a worldwide distribution, and it has a high commercial value. The use of this species as a bioindicator in the marine environment, and the use of measurements of AChE activity in tissues of C. gigas require prior evaluation of organisms exposed to several toxic compounds in the laboratory. In our study, the effects of pesticides on AChE activity in the gills and mantle tissues of C. gigas were analyzed by exposing animals to organophosphate (dichlorvos), carbamate (carbofuran and oxamyl), and organochlorine (lindane) pesticides. Adult Pacific oysters were exposed to several concentrations (0.1-200 uM) of dichlorvos, carbofuran, and oxamyl for 96 hr, and lindane (1.0 and 2.5 uM) was applied for 12 days. In gill tissues, all pesticides analyzed caused a decrease in AChE activity when compared to the control unexposed group. The mean inhibition concentration (IC(50)) values were determined for dichlorvos, carbofuran, and oxamyl pesticides. Dichlorvos had the highest toxic effect, with an IC(50) of 1.08 uM; lesser effects were caused by oxamyl and carbofuran, with IC(50)s of 1.67 and 3.03 uM, respectively. This study reports the effects of pesticides with several chemical structures and validates measurement of AChE activity in the gill tissues of C. gigas for use in environmental evaluations or food quality tests.

For more Ecotoxicity Excerpts (Complete) data for Dichlorvos (16 total), please visit the HSDB record page.

1.90e+00

7.90e+00

3.40e-02

1.50e-01

2.60e-01

5.00e+00

2.90e-01

5.00e-04

Volatile

9.50e+01

7.90e+02

1.60e+00

6.60e+00

2.60e+01

The substance is very toxic to aquatic organisms. This substance does enter the environment under normal use. Great care, however, should be taken to avoid any additional release, for example through inappropriate disposal.

Dichlorvos's production may result in its release to the environment through various waste streams; its use as an insecticide will result in its direct release to the environment. Dichlorvos is a breakdown product of the insecticides trichlorfon or naled, and may be released to the environment where these pesticides are used. If released to air, a vapor pressure of 0.0158 mm Hg at 25 °C indicates dichlorvos will exist solely as a vapor in the atmosphere. Vapor-phase dichlorvos will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals, nitrate radicals and ozone; the half-lives for these reactions in air are estimated to be 11-19 hours, 3.2 hours and 70 days, respectively. Dichlorvos absorbs light in the UV range with a maximum absorbance of 295-305 nm and has a photodegradation half-life of about 7.25 hours in air. If released to soil, dichlorvos is expected to have very high to moderate mobility based upon Koc values of 27.5-151. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 5.7X10-7 atm-cu m/mole. Dichlorvos is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Based on lab and field studies, dichlorvos is expected to degrade in the environment, with dissipation half-lives of <1-16 days. If released into water, dichlorvos may adsorb to suspended solids and sediment based upon the Koc values. In aquatic environments, dichlorvos has been reported as having a half-life of <1 day, with an activated sludge inoculum 3.5 days, and reached 8-14% of theoretical BOD in 8 days using a sewage inoculum. Slow volatilization from water surfaces is expected based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 95 days and 1.9 years, respectively. BCFs in fish of <0.5-0.8 suggest bioconcentration in aquatic organisms is low. Dichlorvos has been reported to undergo hydrolysis in environmental aqueous systems in <1-70 days depending on the temperature, pH and other environmental conditions. Occupational exposure to dichlorvos may occur through inhalation and dermal contact with this compound at workplaces where dichlorvos is produced or used. Monitoring data indicate that the general population may be exposed to dichlorvos via inhalation of ambient air, ingestion of food, and dermal contact with consumer products containing dichlorvos. (SRC)

Dichlorvos is not known to occur as a natural product(1).

Dichlorvos's production may result in its release to the environment through various waste streams; its use as an insecticide(1) will result in its direct release to the environment(SRC). Dichlorvos is a breakdown product of the insecticides trichlorfon(2) and naled(3), and may be released to the environment where these pesticides are used(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 27.5-151(2-4) indicate that dichlorvos is expected to have very high to moderate mobility in soil. Volatilization of dichlorvos from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.7X10-7 atm-cu m/mole(SRC), derived from its vapor pressure, 0.0158 mm Hg(5), and water solubility, 8000 mg/L(6). Dichlorvos is not expected to volatilize from dry soil surfaces(SRC) based on its vapor pressure(5). Dichlorvos had a field dissipation half-life of 1 day(4). Dichlorvos, added to Houston black clay, degraded 71% (49.7% hydrolysis, 21.3% biodegradation) in 10 days(7). The presence of active microorganisms reduced the half-life of dichlorvos in clay and calcareous soil from 0.9 to 0.75 days and 0.85 to 0.70 days, respectively(8). The average first-order rate constants of dichlorvos in an acidic silty clay soil and a neutral sandy clay soil were 0.0423 and 0.04443 L/day, respectively; the half-life in both soils was 16 days(9).

AQUATIC FATE: Based on a classification scheme(1), Koc values of 27.5-151(2-4) indicate that dichlorvos may adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(5) based upon an estimated Henry's Law constant of 5.7X10-7 atm-cu m/mole(SRC) derived from its vapor pressure, 0.0158 mm Hg(6), and water solubility, 8000 mg/L(7). Using this Henry's Law constant and an estimation method(5), volatilization half-lives for a model river and model lake are 95 days and 1.9 years, respectively(SRC). Dichlorvos has been reported to undergo hydrolysis in environmental aqueous systems in <1-70 days depending on the temperature, pH and other environmental conditions(6,8-10). According to a classification scheme(11), BCFs of <0.5-0.8 in fish(12-13), suggest bioconcentration in aquatic organisms is low. In aquatic environments, dichlorvos has been reported as having half-lives of <1 days(6) to 3.5 days with an activated sludge inoculum(3) and has reached 8-14% of theoretical BOD in 8 days using a sewage inoculum(14).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), dichlorvos, which has a vapor pressure of 0.0158 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase dichlorvos is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals, ozone and nitrate radicals; the half-life for these reactions in air is estimated to be 11-19 hours, 70 days and 3.2 hours(SRC), calculated from respective rate constants of 2.0X10-11 to 3.5X10-11(3-5), 1.7X10-19(5) and 2.5X10-13(5) cu cm/molecule-sec. Dichlorvos absorbs light in the UV range with a maximum absorbance of 295-305 nm and was found to have a photodegradation rate constant of 265.2X10-7 L/sec, giving it a photodegradation half-life of about 7.25 hours(6).

AEROBIC: Dichlorvos was reported to have a half-life of <1 day in biologically active soils and water systems(1). Dichlorvos was listed as being amenable to biodegradation after acclimation(2). The biodegradation rate constant and half-life for dichlorvos was determined to be 0.20 L/d and 3.5 days, respectively, in an aerobic biodegradability test using an activated sludge inoculum incubated at 20 °C for 50 days(3). Dichlorvos (present at high levels) was degraded but not completely removed when incubated with sewage for 7 days at 29 °C; biodegradation products were dichloroethanol, dichloroacetic acid and ethyl dichloroacetate(4). Dichlorvos was found to have 8-14% of theoretical BOD in an 8 day laboratory test using a sewage inoculum(5). Dichlorvos, added to Houston black clay, degraded 71% (49.7% hydrolysis, 21.3% biodegradation) in 10 days(6). The presence of active microorganisms reduced the half-life of dichlorvos in clay and calcareous soil from 0.9 to 0.75 days and 0.85 to 0.70 days, respectively(7). The average first-order rate constants of dichlorvos in an acidic silty clay soil and a neutral sandy clay soil were 0.0423 and 0.04443 L/day, respectively; the half-life in both soils was reported as 16 days(8).

ANAEROBIC: A low concentration of dichlorvos (3 mg-C/L) degraded within 7 days in an anaerobic biodegradability test at 37 °C(1). The biodegradation rate constant and half-life for dichlorvos was determined to be 0.20 L/d and 3.5 days, respectively, in a study using 30 mg/L anaerobic microorganisms cultured by an artificial sewage incubated at 20 °C under anaerobic conditions for 50 days(2).

The rate constant for the vapor-phase reaction of dichlorvos with photochemically-produced hydroxyl radicals has been measured as 2.0X10-11 to 3.5X10-11 cu cm/molecule-sec at 25 °C(1-3). This corresponds to an atmospheric half-life of about 11-19 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1-3). The rate constant for the vapor-phase reaction of dichlorvos with ozone has been reported as 1.7X10-19 cu cm/molecule-sec at 25 °C(3). This corresponds to an atmospheric half-life of about 70 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(4). The rate constant for the vapor-phase reaction of dichlorvos with nitrate radicals has been reported as 2.5X10-13 cu cm/molecule-sec at 25 °C(3). This corresponds to an atmospheric half-life of about 3.2 hours at an atmospheric concentration of 2.4X10+8 nitrate molecules per cu cm(5). These half-lives indicate that dichlorvos degradation in the air will be mainly by reaction with hydroxyl radicals in the day and nitrate radicals at night(3). Dichlorvos absorbs light in the UV range with a maximum absorbance of 295-305 nm and was found to have a photodegradation rate constant of 265.2X10-7 L/sec, giving it a photodegradation half-life of about 7.25 hours(6).

The neutral hydrolysis rate constant of dichlorvos at 20 °C was reported as 3.67X10+5 L/hour giving a half-life of 7.9 days at pH 7(1). Dichlorvos is slowly hydrolyzed in water and in acidic media, and rapidly hydrolysed by alkalis, to dimethyl hydrogen phosphate and dichloroacetaldehyde; estimated half-lives are 31.9, 2.9 and 2.0 days at pH values of 4, 7 and 9, respectively(2). Hydrolysis half-lives were 11 days, 5 days and 21 hours at respective pH values of 5, 7 and 9 with degradation products of 2,2-dichloroacetic acid, 2,2-dichloroacetaldehyde, desmethyl dichlorvos and glyoxylic acid(3). It was reported that dichlorvos undergoes hydrolysis in damp media with phosphoric acid formation and that its half-life in water, depending on temperature and pH, is 19-79 hours(4). Dichlorvos degraded 8, 18, 64 and 90% in 24 hours at pH 6.2, 8.2, 8.7 and 9.3, respectively; no degradation occurred below pH 3.3 after 96 hours(5). Another study found that the hydrolysis half-life decreased from 77 hours to 5 hours when the pH increased from 5.4 to 8 at 37.5 °C(6). At pH 5, the half-life was 10.0, 2.6 and 0.7 days at 10, 20 and 30 °C, respectively(6). Hydrolysis is an important degradation mechanism for dichlorvos in soil depending on th pH(7); when added to Houston black clay, it degraded 71% (49.7% hydrolysis, 21.3% biodegradation) in 10 days(5).

The rate of hydrolysis and the half-lives of dichlorvos in freshwater, brackish water, and sea sediments collected from 16 locations in the Bay of Bengal along the east coast of India in January and September 1984 were reported as follows(1):[Table#1031]

The whole-body BCF measured in carp (Cyprinus carpio) was <0.5 after exposure to 1.3 ug/L of dichlorvos for 7 days(1). The excretion rate and half-life were 0.56 L/hour and 0.6 hours, respectively, indicating that dichlorvos is readily eliminated from carp(1). Willow shiner (Gnathopogon caerulescens), exposed to 2.3 ug/L of dichlorvos for 7 days had an average whole-body BCF of 0.8(2). According to a classification scheme(3), these BCF suggest bioconcentration in aquatic organisms is low.

Measured Koc values reported in the 1993 UK Database for dichlorvos were reported as 27.5-151(1). The Koc for dichlorvos in three Japanese black soils with organic carbon content of 2.3-6.8% was reported as 47(2). The Koc was also reported as 50(3). According to a classification scheme(4), these Koc values suggest that dichlorvos is expected to have very high to moderate mobility in soil. In a field experiment, 18-20% of the dichlorvos which was sprayed on the ground had penetrated the soil to a depth of 30 cm within 5 days(5). The mobility of dichlorvos in soil is decreased by the addition of soil amendments such as calcium carbonate(6). Mobility of dichlorvos in soil decreases with increasing soil pH(7).

The Henry's Law constant for dichlorvos is estimated as 5.7X10-7 atm-cu m/mole(SRC) derived from its vapor pressure, 0.0158 mm Hg(1), and water solubility, 8000 mg/L(2). This Henry's Law constant indicates that dichlorvos is expected to slowly volatilize from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 95 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 1.9 years(SRC). The average decrease of dichlorvos after seven days of aeration in water was 16%/day, while without aeration the average decrease was 6%/day(4). Dichlorvos's estimated Henry's Law constant indicates that slow volatilization from moist soil surfaces may occur(SRC). Dichlorvos is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

GROUNDWATER: Dichlorvos was not detected (detection limit not reported) in 46 wells located in 7 counties of California tested Jul 1, 1994 to Jun 30, 1995(1).

SRP: 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 air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber; Contaminated packaging: Dispose of as unused product.

Fifty percent hydrolysis is obtained in pure water in 25 min at 70 °C and in 61.5 days at 20 °C. A buffered solution yields 50% hydrolysis (37.5 °C) in 301 min at pH 8, 462 min at pH 7, 620 min at pH 5.4. Hydrolysis yields no toxic residues. Incineration in a furnace equipped with an afterburner and alkaline scrubber is recommended as is alkaline hydrolysis followed by soil burial. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency or by contacting your regional EPA office.

For more Disposal Methods (Complete) data for Dichlorvos (11 total), please visit the HSDB record page.

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion and poison hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Health: TOXIC; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind, uphill and/or upstream. Ventilate closed spaces before entering. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible. /Organophosphorus pesticide, liquid, flammable, poisonous; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, poisonous, flammable; Organophosphorus pesticide, liquid, toxic, flammable/

For more DOT Emergency Guidelines (Complete) data for Dichlorvos (16 total), please visit the HSDB record page.

UN 2784; Organophosphorus pesticides, liquid, flammable, toxic, flash point less than 23 °C

UN 2783; Organophosphorus pesticides, solid, toxic

UN 3017; Organophosphorus pesticides, liquid, toxic, flammable, flash point not less than 23 °C

UN 3018; Organophosphorus pesticides, liquid, toxic

For more Shipping Name/ Number DOT/UN/NA/IMO (Complete) data for Dichlorvos (8 total), please visit the HSDB record page.

49 215 34; Dichlorvos (agricultural insecticides, not elsewhere classified, liquid)

49 215 35; Dichlorvos (agricultural insecticides, not elsewhere classified, other than liquid)

49 215 36; Dichlorvos (insecticides, other than agricultural, not elsewhere classified)

49 215 37; Dichlorvos mixture, dry (agricultural insecticides, other than liquid)

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials. Organophosphorus pesticide, solid, toxic; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, toxic, flammable; and Organophosphorus pesticide, liquid, toxic are included on the dangerous goods list. /Organophosphorus pesticide, solid, toxic; Organophosphorus pesticide, liquid, flammable, toxic; Organophosphorus pesticide, liquid, toxic, flammable; and Organophosphorus pesticide, liquid, toxic/

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article. /Organophosphorus pesticide, solid, toxic; Organophosphorus pesticide, liquid, flammable, toxic, flashpoint less than 23 °C; Organophosphorus pesticide, liquid, toxic, flammable, flashpoint not less than 23 °C; and Organophosphorus pesticide, liquid, toxic are included on the dangerous goods list. /Organophosphorus pesticide, liquid, flammable, toxic, flashpoint less than 23 °C; Organophosphorus pesticide, liquid, toxic, flammable, flashpoint not less than 23 °C; and Organophosphorus pesticide, liquid, toxic/

PRECAUTIONS FOR "CARCINOGENS": Procurement ... of unduly large amt ... should be avoided. To avoid spilling, carcinogens should be transported in securely sealed glass bottles or ampoules, which should themselves be placed inside strong screw-cap or snap-top container that will not open when dropped & will resist attack from the carcinogen. Both bottle & the outside container should be appropriately labelled. ... National post offices, railway companies, road haulage companies & airlines have regulations governing transport of hazardous materials. These authorities should be consulted before ... material is shipped. /Chemical Carcinogens/

For more Shipment Methods and Regulations (Complete) data for Dichlorvos (6 total), please visit the HSDB record page.

Do not transport with food and feedstuffs. Marine pollutant.

Symbol: T+, N; R: 24/25-26-43-50; S: (1/2)-28-36/37-45-61

UN Hazard Class: 6.1; UN Pack Group: II