Methylmercury chloride

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

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

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

H351: Suspected of causing cancer [Warning Carcinogenicity]

H360Df: May damage the unborn child; Suspected of damaging fertility [Danger Reproductive toxicity]

H362: May cause harm to breast-fed children [Reproductive toxicity, effects on or via lactation]

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

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

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

P203, P260, P262, P263, P264, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P316, P318, P319, P320, P321, P330, P361+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

H300 (100%): Fatal if swallowed [Danger Acute toxicity, oral]

H310 (100%): Fatal in contact with skin [Danger Acute toxicity, dermal]

H330 (100%): Fatal if inhaled [Danger Acute toxicity, inhalation]

H373 (97.7%): May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

H400 (97.7%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

H410 (100%): Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P260, P262, P264, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P316, P319, P320, P321, P330, P361+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 44 reports by companies from 4 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.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: Some heavy metals are VERY TOXIC POISONS, especially if their salts are very soluble in water (e.g., lead, chromium, mercury, bismuth, osmium, and arsenic). IMMEDIATELY call a hospital or poison control center and locate activated charcoal, egg whites, or milk in case the medical advisor recommends administering one of them. Also locate Ipecac syrup or a glass of salt water in case the medical advisor recommends inducing vomiting. Usually, this is NOT RECOMMENDED outside of a physician's care. If advice from a physician is not readily available and the victim is conscious and not convulsing, give the victim a glass of activated charcoal slurry in water or, if this is not available, a glass of milk, or beaten egg whites and IMMEDIATELY transport victim to a hospital. If the victim is convulsing or unconscious, do not give anything by mouth, assure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992)

Fires involving this material can be controlled with a dry chemical, carbon dioxide or Halon extinguisher. (NTP, 1992)

If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty). Use water in flooding quantities as fog. Use foam, dry chemical, or carbon dioxide. /Mercury compounds, solid, n.o.s./

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. /Mercury alkyl compounds/

Wear appropriate chemical protective gloves, boots, and goggles ... Wear positive pressure self-contained breathing apparatus when fighting fires involving this material. /Mercury compounds, solid, n.o.s./

Excerpt from ERG Guide 151 [Substances - Toxic (Non-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)

PRECAUTIONS FOR "CARCINOGENS": A high-efficiency particulate arrestor (HEPA) or charcoal filters can be used to minimize amt of carcinogen in exhausted air ventilated safety cabinets, lab hoods, glove boxes or animal rooms ... Filter housing that is designed so that used filters can be transferred into plastic bag without contaminating maintenance staff is avail commercially. Filters should be placed in plastic bags immediately after removal ... The plastic bag should be sealed immediately ... The sealed bag should be labelled properly ... Waste liquids ... should be placed or collected in proper containers for disposal. The lid should be secured & the bottles properly labelled. Once filled, bottles should be placed in plastic bag, so that outer surface ... is not contaminated ... The plastic bag should also be sealed & labelled. ... Broken glassware ... should be decontaminated by solvent extraction, by chemical destruction, or in specially designed incinerators. /Chemical Carcinogens/

Spill Handling: Evacuate persons not wearing protective equipment from area of spill or leak until clean-up is complete. Remove all ignition sources. Spills should be collected with special mercury vapor suppressants or special vacuums and deposited in sealed containers. Kits specific for clean-up of mercury spills are available. Ventilate area after clean-up is complete. 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. /Mercury alkyl compounds/

Environmental considerations - 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./ Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. /Mercury compounds, solid, n.o.s./

Environmental considerations - water spill: Use natural barriers or oil spill control booms to limit spill travel. Use natural deep water pockets, excavated lagoons, or sand bag barriers to trap material at bottom. Remove trapped material with suction hoses. /Mercury compounds, solid, n.o.s./

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

Mercury is an element, and therefore its chemical structure cannot be further broken down. In its elemental form, mercury is highly toxic when inhaled. Therefore, incineration of mercury is not recommended as a disposal method. Mercury-containing waste products include waste effluents from chloralkali plants and discarded mercury-containing mechanical and electrical devices ... Under current federal guidelines, mercury and its compounds are considered hazardous substances, and various regulations are in effect to control the emission of mercury into the environment (especially organic compounds) ... Emissions from mercury ore processing facilities and mercury cell chloralkali plants are limited to 2.3 kg/day/facility. Emissions of mercury from the incineration or drying of wastewater sludges is limited to 3.2 kg/day/facility ... In addition, dumping wastes containing more than trace amounts of mercury is prohibited. Recycling of mercury-containing compounds is an important method of disposal. Recycling (retorting) is a treatment for five categories of mercury wastes including: (D009) characteristic mercury; (K106) chloralkali waste; (P065) mercury fulminate; (P092) phenylmercuric acetate; and (U151) elemental mercury ... From 1987 to 1991, annual production of mercury from old scrap averaged nearly 180 metric tons, equivalent to 16% of the average reported consumption during that period (Jasinski 1993). Virtually all mercury can be reclaimed from mercury cell chloralkali plants, electrical apparati, and control instruments when plants are dismantled or scrapped ... Increased recycling would decrease the mercury load from waste sites and treatment plants. As environmental concerns increase with respect to the disposal of mercury, the recovery by recycling and industrial processes will become a more significant source of domestic supply ...

PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/

PRECAUTIONS FOR "CARCINOGENS": ... Incineration may be only feasible method for disposal of contaminated laboratory waste from biological expt. However, not all incinerators are suitable for this purpose. The most efficient type ... is probably the gas-fired type, in which a first-stage combustion with a less than stoichiometric air:fuel ratio is followed by a second stage with excess air. Some ... are designed to accept ... aqueous & organic-solvent solutions, otherwise it is necessary ... to absorb soln onto suitable combustible material, such as sawdust. Alternatively, chem destruction may be used, esp when small quantities ... are to be destroyed in laboratory. /Chemical Carcinogens/

For more Disposal Methods (Complete) data for Methylmercuric chloride (7 total), please visit the HSDB record page.

If material not involved in fire: Keep material out of water sources and sewers. /Mercury compounds, solid, n.o.s./

Personnel protection: Avoid breathing dusts and fumes from burning material. Keep upwind. Avoid bodily contact with the material ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water ... If contact with the material anticipated, wear appropriate chemical protective clothing. /Mercury compounds, solid, n.o.s./

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

Contact lenses should not be worn when working with this chemical. /Mercury alkyl compounds/

For more Preventive Measures (Complete) data for Methylmercuric chloride (13 total), please visit the HSDB record page.

SMALL SPILLS AND LEAKAGE: Should a spill occur while you are handling this chemical, FIRST REMOVE ALL SOURCES OF IGNITION, then you should dampen the solid spill material with 60-70% ethanol and transfer the dampened material to a suitable container. Use absorbent paper dampened with 60-70% ethanol to pick up any remaining material. Seal the absorbent paper, and any of your clothes, which may be contaminated, in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with 60-70% ethanol followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

STORAGE PRECAUTIONS: You should protect this material from exposure to light, and store it under ambient temperatures. (NTP, 1992)

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/

These compounds should be stored in a refrigerator or a cool dry place away from oxidizers. A regulated, marked area should be established where this chemical is handled, used, or stored ... /Mercury alkyl compounds/

0.01 [mg/m3], Ceiling(OSHA) = 0.04 mg/m3, as Hg

2 mg Hg/m3 (NIOSH, 2024)

2.0 [mg/m3], as Hg

0.01 [mg/m3], as Hg

0.03 [mg/m3], as Hg

8 hr Time Weighted Avg (TWA): 0.01 mg/cu m; 15 min Short Term Exposure Limit (STEL) 0.03 mg/cu m. Skin. /Mercury, alkyl compounds, as Hg/

Chronic Inhalation: 0.0002 mg/m3 (L134)

MINIMUM PROTECTIVE CLOTHING: If Tyvek-type disposable protective clothing is not worn during handling of this chemical, wear disposable Tyvek-type sleeves taped to your gloves.

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992)

PRECAUTIONS FOR "CARCINOGENS": ... Dispensers of liq detergent /should be available./ ... Safety pipettes should be used for all pipetting. ... In animal laboratory, personnel should ... wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. ... Gowns ... /should be/ of distinctive color, this is a reminder that they are not to be worn outside the laboratory. /Chemical Carcinogens/

Methyl mercury(ii)chloride appears as white microcrystals or crystals. (NTP, 1992)

White solid; [CAMEO]

White crystals ... or plates from ethanol

Characteristic

338 °F (NTP, 1992)

less than 0.1 mg/mL at 70 °F (NTP, 1992)

METHYL- & ETHYLMERCURY CHLORIDE HAVE A HIGH SOLUBILITY IN SOLVENTS & LIPIDS; SHORT-CHAIN ALKYLMERCURIC COMPOUNDS FORM SALTS WITH HALOGENS, WHICH ARE HIGHLY VOLATILE AT ROOM TEMP; SATURATION CONCN OF METHYLMERCURY CHLORIDE AT 20 °C IS 90000 MG MERCURY/CU M; OTHER SALTS, SUCH AS HYDROXIDE & NITRATE OF METHYLMERCURY ARE LESS VOLATILE /METHYLMERCURY COMPOUNDS/

4.06 at 77 °F (NTP, 1992) - Denser than water; will sink

0.0085 mmHg (NTP, 1992)

8.5X10-3 mm Hg at 25 °C

log Kow = 0.41

Henry's Law constant = 3.7X10-7 atm-cu m/mol at 25 °C

When heated to decomposition it emits very toxic fumes of /chlorine/ and /mercury/.

Metals -> Metals, Organic Compounds

Carcinogens

Aqueous solutions at a concentration of 0.25 mg / mL are stable for 3 weeks in the dark at room temperature. Aqueous 0.0001 M solutions show no degradation after 17.1 hours of midday sunlight. High intensity UV irradiation of solutions causes decomposition (NTP, 1992).

Organometallics

METHYL MERCURY(II)CHLORIDE may be sensitive to light.

High-affinity binding of the divalent mercuric ion to thiol or sulfhydryl groups of proteins is believed to be the major mechanism for the activity of mercury. Through alterations in intracellular thiol status, mercury can promote oxidative stress, lipid peroxidation, mitochondrial dysfunction, and changes in heme metabolism. Mercury is known to bind to microsomal and mitochondrial enzymes, resulting in cell injury and death. For example, mercury is known to inhibit aquaporins, halting water flow across the cell membrane. It also inhibits the protein LCK, which causes decreased T-cell signalling and immune system depression. Mercury is also believed to inhibit neuronal excitability by acting on the postsynaptic neuronal membrane. It also affects the nervous system by inhibiting protein kinase C and alkaline phosphatase, which impairs brain microvascular formation and function, as well as alters the blood-brain barrier. Organic mercury exerts developmental effects by binding to tubulin, preventing microtubule assembly and causing mitotic inhibition. Mercury also produces an autoimmune response, likely by modification of major histocompatibility complex (MHC) class II molecules, self peptides, T-cell receptors, or cell-surface adhesion molecules. (L7, A8, A25, A26)

Methylmercury compounds are possibly carcinogenic to humans (Group 2B). There is sufficient evidence in experimental animals for the carcinogenicity of methylmercury chloride. /Methylmercury compounds/

2B, possibly carcinogenic to humans. (L135)

Mercury mainly affects the nervous system. Exposure to high levels of metallic, inorganic, or organic mercury can permanently damage the brain, kidneys, and developing fetus. Effects on brain functioning may result in irritability, shyness, tremors, changes in vision or hearing, and memory problems. Acrodynia, a type of mercury poisoning in children, is characterized by pain and pink discoloration of the hands and feet. Mercury poisoning can also cause Hunter-Russell syndrome and Minamata disease. (L7)

Oral (L7) ; inhalation (L7); dermal (L7)

Common symptoms include peripheral neuropathy (presenting as paresthesia or itching, burning or pain), skin discoloration (pink cheeks, fingertips and toes), edema (swelling), and desquamation (dead skin peels off in layers). (A5)

Neurotoxin - Other CNS neurotoxin

Nephrotoxin - The chemical is potentially toxic to the kidneys in the occupational setting.

Reproductive Toxin - A chemical that is toxic to the reproductive system, including defects in the progeny and injury to male or female reproductive function. Reproductive toxicity includes developmental effects. See Guidelines for Reproductive Toxicity Risk Assessment.

LC50 (mice) = 80 mg/m3/4h

LD50: 21 mg/kg (Oral, Guinea pig) (L447)

LD50: 11 mg/kg (Intraperitoneal, Rat) (L447)

LD50 Rat oral 29.915 mg/kg

LD50 Rat ip 11 mg/kg

LD50 Mouse oral 57.6 mg/kg

LD50 Mouse ip 10 mg/kg

For more Non-Human Toxicity Values (Complete) data for Methylmercuric chloride (7 total), please visit the HSDB record page.

Mercury poisoning is treated by immediate decontamination and chelation therapy using DMSA, DMPS, DPCN, or dimercaprol. (A7)

Adult mallards (Anas platyrhynchos) were fed ... a diet 10 ppm mercury plus 10 ppm selenium. ... When the diet contained 10 ppm selenium in addition to the 10 ppm mercury, none of 12 males became sick. In contrast to the protective effect of selenium against mercury poisoning in males, selenium plus mercury was worse than selenium or mercury alone for some measurements of reproductive success. Both selenium and mercury lowered duckling production through reductions in hatching success and survival of ducklings, but the combination of mercury plus selenium was worse than either mercury or selenium alone. Controls produced an average of 7.6 young per female ... and females fed both mercury and selenium produced 0.2 young. Teratogenic effects also were worse for the combined mercury plus selenium treatment; deformities were recorded in 6.1% of the embryos of controls, 16.4% for those fed methylmercury chloride, 36.2% for those fed selenomethionine, and 73.4% for those fed methylmercury chloride and selenomethionine. The presence of methylmercury in the diet greatly enhanced the storage of selenium in tissues. The livers of males fed 10 ppm selenium contained a mean of 9.6 ppm selenium, whereas the livers of males fed 10 ppm selenium plus 10 ppm mercury contained a mean of 114 ppm selenium. However, selenium did not enhance the storage of mercury. The results show that mercury and selenium may be antagonistic to each other for adults and synergistic to young, even within the same experiment.

Groups of 10 /male ICR/ mice were given methylmercury chloride at a concentration of 40 mg/g of diet, with or without melatonin at a concentration of 20 mg/mL in drinking-water, for 5 weeks. Greater numbers of animals treated with methylmercury alone showed signs of neurotoxicity (abnormal righting reflex, staggering gait, fallen posture) and a higher rate of mortality after 35 days of treatment than the group receiving methylmercury plus melatonin. It was suggested that the anti-oxidative capacity of melatonin reduces the toxicity of methylmercury ...

Groups of six pregnant CD-1 mice were given a single intraperitoneal dose of methylmercury chloride of either 0 or 10 mg/kg bw on day 9 of gestation, and litters were examined for teratological effects on day 17 of gestation. Co-exposure to methylmercury chloride and PK11195 (4 mg/kg), a ligand for the mitochondrial peripheral-type benzodiazepine receptor, reduced the overall incidence of fetal malformation by approximately 2.5-fold... In embryos collected from dams 3 hr after treatment with methylmercury chloride at 5 mg/kg bw on day 9 of gestation, expression of mitochondrial 16S rRNA was decreased approximately three-fold compared with controls, while co-treatment with PK11195 (4 mg/kg) prevented any decrease.

If this chemical gets into the eyes, irrigate immediately. If this chemical contacts the skin, wash with soap immediately. If a person breathes in large amounts of this chemical, move the exopsed person to fresh air at once and perform artificial respiration. When this chemical has been swallowed, get medical attention. Give large quantities of water. Do not make an unconscious person vomit. /Methyl mercury compounds/

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Mercury and related compounds/

/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with available water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Mercury and related compounds/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Mercury and related compounds/

/SIGNS AND SYMPTOMS/ Methylmercury compounds induce adverse effects on human development - most notably microcephaly and deficits in neurological development ... The dose levels of methylmercury compounds that affect reproduction and development are generally lower than those of inorganic mercury and affect a wider range of end-points. /Methylmercury compounds/

/SIGNS AND SYMPTOMS/ The most consistent and pronounced effects of /chronic/ exposure to ... short-chain alkylmercury compounds such as methylmercury are on CNS. Effects ... are neurological and psychiatric. Common symptoms include depression, irritability, exaggerated response to stimulation (erethism), excessive shyness, insomnia, emotional instability, forgetfulness, confusion, and vasomotor disturbances such as excessive perspiration and uncontrolled blushing. Tremors are also common ... Sensory effects ... occur more consistently and at lower levels of exposure. Earliest sign is paresthesia. At ... higher levels of exposure other effects occur, such as ataxia, constriction of visual field, dysarthria, and hearing defects. These alterations are irreversible when poisoning is severe. Neuropsychiatric effects ... are likely to involve spontaneous fits of laughing and crying and intellectual deterioration.

/SIGNS AND SYMPTOMS/ In humans the neurotoxic symptoms of methyl mercury salts, the Hunter-Russel syndrome, involve focal cerebral and cerebellar atrophy. The granular cell layer of neocerebellum is affected followed by cortical atrophy of area striata, which leads to blindness.

/GENOTOXICITY/ ... Four studies involving subjects exposed to methylmercury compounds from contaminated seal or fish meat were either inconclusive or indicated slight chromosomal effects. /Methylmercury compounds/

For more Human Toxicity Excerpts (Complete) data for Methylmercuric chloride (6 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Methylmercury toxicity is very strain- and sex-specific in mice. A single oral dose of methylmercuric chloride at 16 mg Hg/kg resulted in the death of 4 of 6 male mice (C57BL/6N Jcl strain) but no deaths in females ... No increase in mortality was observed in female mice until 40 mg Hg/kg was administered, at which dosage 4 of 6 females died.

/LABORATORY ANIMALS: Acute Exposure/ A decrease in heart rate was observed in male rats (strain unknown) given 2 gavage doses of 12 mg Hg/kg as methylmercuric chloride.

/LABORATORY ANIMALS: Acute Exposure/ Administration of methylmercuric chloride to mice (strain and sex unknown) in a single gavage dose of 16 mg Hg/kg resulted in decreased renal function (decreased phenolsulfonphthalein excretion), increased plasma creatinine, and swelling of tubular epithelial cells, with exfoliation of the cells into the tubular lumen.

/LABORATORY ANIMALS: Acute Exposure/ Although no effects were observed after a single gavage dose of 8 mg Hg/kg ..., 5 daily gavage doses of 8 mg Hg/kg/day as methylmercuric chloride in rats (strain and sex unknown) resulted in vacuolization and tubular dilation in the proximal tubules with ongoing regeneration.

For more Non-Human Toxicity Excerpts (Complete) data for Methylmercuric chloride (88 total), please visit the HSDB record page.

LC50; Species: Coturnix japonica (Japanese quail, age 14 days) diet 47 ppm for 5 days (95% confidence interval: 36-60 ppm)

LD50; Species: Coturnix japonica (Japanese quail, age 17 days) oral via capsule 18 mg/kg (95% confidence interval: 14-24 mg/kg)

EC50; Species: Anabaena flosaquae (Blue-green algae); Conditions: freshwater, static, 23-25 °C, pH 6.2-6.8; Concentration: 2.8 ug/L for 24 hr; Effect: growth, general

EC50; Species: Anacystis nidulans (Blue-green algae); Conditions: freshwater, static, 23-25 °C, pH 6.2-6.8; Concentration: 5.0 ug/L for 24 hr; Effect: growth, general

For more Ecotoxicity Values (Complete) data for Methylmercuric chloride (28 total), please visit the HSDB record page.

/BIRDS and MAMMALS/ Sixty breeding pairs of captive American kestrels (Falco sparverius) were exposed to a range of sublethal dietary concentrations of mercury (Hg), in the form of methylmercuric chloride, and their subsequent reproduction was measured. Egg production, incubation performance, and the number and percent of eggs hatched decreased markedly between 3.3 and 4.6 mg/kg dry weight of Hg (1.2 and 1.7 mg/kg wet wt), in the diet. The number of fledglings and the percent of nestlings fledged were reduced markedly at 0.7 mg/kg dry weight (0.3 mg/kg wet wt) and declined further between 2 and 3.3 mg/kg dry weight (0.7 and 1.2 mg/kg wet wt). Dietary concentrations of 4.6 mg/kg dry weight (1.7 mg/kg wet wt) were associated with total fledging failure. The estimated decline in fledged young per pair (24%, Bayesian regression) for kestrels consuming 0.7 mg/kg dry weight (0.3 mg/kg wet wt) raises concerns about population maintenance in areas subject to high inputs of anthropogenic Hg. Mercury concentrations in 20 second-laid eggs collected from all groups were related to dietary concentrations of Hg, and the Hg concentrations in 19 of these eggs were related to eggs laid and young fledged. Concentrations of Hg in eggs from the highest diet group (5.9 mg/kg dry wt; 2.2 mg/kg wet wt) were higher than egg concentrations reported for either wild birds or for captive birds (nonraptors) fed dry commercial food containing 5 mg/kg methylmercury. Accumulation ratios of Hg from diets to eggs were higher than those reported for feeding studies with other species.

LC50; Species: Coturnix japonica (Japanese quail, age 14 days) diet 47 ppm for 5 days (95% confidence interval: 36-60 ppm)

LD50; Species: Coturnix japonica (Japanese quail, age 17 days) oral via capsule 18 mg/kg (95% confidence interval: 14-24 mg/kg)

EC50; Species: Anabaena flosaquae (Blue-green algae); Conditions: freshwater, static, 23-25 °C, pH 6.2-6.8; Concentration: 2.8 ug/L for 24 hr; Effect: growth, general

EC50; Species: Anacystis nidulans (Blue-green algae); Conditions: freshwater, static, 23-25 °C, pH 6.2-6.8; Concentration: 5.0 ug/L for 24 hr; Effect: growth, general

For more Ecotoxicity Values (Complete) data for Methylmercuric chloride (28 total), please visit the HSDB record page.

/BIRDS and MAMMALS/ Sixty breeding pairs of captive American kestrels (Falco sparverius) were exposed to a range of sublethal dietary concentrations of mercury (Hg), in the form of methylmercuric chloride, and their subsequent reproduction was measured. Egg production, incubation performance, and the number and percent of eggs hatched decreased markedly between 3.3 and 4.6 mg/kg dry weight of Hg (1.2 and 1.7 mg/kg wet wt), in the diet. The number of fledglings and the percent of nestlings fledged were reduced markedly at 0.7 mg/kg dry weight (0.3 mg/kg wet wt) and declined further between 2 and 3.3 mg/kg dry weight (0.7 and 1.2 mg/kg wet wt). Dietary concentrations of 4.6 mg/kg dry weight (1.7 mg/kg wet wt) were associated with total fledging failure. The estimated decline in fledged young per pair (24%, Bayesian regression) for kestrels consuming 0.7 mg/kg dry weight (0.3 mg/kg wet wt) raises concerns about population maintenance in areas subject to high inputs of anthropogenic Hg. Mercury concentrations in 20 second-laid eggs collected from all groups were related to dietary concentrations of Hg, and the Hg concentrations in 19 of these eggs were related to eggs laid and young fledged. Concentrations of Hg in eggs from the highest diet group (5.9 mg/kg dry wt; 2.2 mg/kg wet wt) were higher than egg concentrations reported for either wild birds or for captive birds (nonraptors) fed dry commercial food containing 5 mg/kg methylmercury. Accumulation ratios of Hg from diets to eggs were higher than those reported for feeding studies with other species.

/BIRDS and MAMMALS/ American kestrels (Falco sparverius) were fed meat diets containing 0, 3, 6, or 12 ppm (dry weight) methylmercury chloride. Birds fed the 12-ppm diet started to show signs of neurotoxicity after 26 days and all died in 39-49 days. One male kestrel fed the 6-ppm diet died after 75 days of exposure and several others showed signs of neurotoxicity after 45 days. None of the birds fed the 3-ppm diet died or showed signs of toxicity. After 59 days of exposure, mercury concentrations in the liver, kidney, and blood of nonreproducing kestrels increased with increasing dietary concentration. Tissue concentrations of mercury also steadily increased over time in birds fed diets with 6 ppm mercury, which were necropsied at 8, 15, 29, or 59 days of exposure, reaching mean total mercury concentrations of 57, 46, and 45 ppm (wet weight) at 59 days in the liver, kidney, and whole blood, respectively. Two pairs of kestrels at each dietary concentration were allowed to breed. Eggs averaged 8.3 and 18.1 ppm (wet weight) total mercury from birds fed 3- and 6-ppm diets, respectively. Feathers grown during mercury exposure contained high concentrations of mercury: Birds fed 3- and 6-ppm diets contained 275 and 542 ppm total mercury, respectively.

/BIRDS and MAMMALS/ Breeding pairs of mallards (Anas platyrhynchos) were fed a control diet or a diet containing 0.5 ug/g mercury (Hg) in the form of methylmercury chloride. There were no effects of Hg on adult weights and no overt signs of Hg poisoning in adults. The Hg-containing diet had no effect on fertility of eggs, but hatching success of eggs was significantly higher for females fed 0.5 ug/g Hg (71.8%) than for controls (57.5%). Survival of ducklings through 6 days of age was the same (97.8%) for controls and mallards fed 0.5 ug/g mercury. However, the mean number of ducklings produced per female was significantly higher for the pairs fed 0.5 ug/g Hg (21.4) than for controls (16.8). Although mercury in the parents' diet had no effect on mean duckling weights at hatching, ducklings from parents fed 0.5 ug/g Hg weighed significantly more (mean = 87.2 g) at 6 days of age than did control ducklings (81.0 g). The mean concentration of Hg in eggs laid by parents fed 0.5 ug/g mercury was 0.81 ug/g on a wet-weight basis.

/BIRDS and MAMMALS/ The ideal study of the effects of methylmercury on the reproductive success of a species of bird would be one in which eggs contained mercury concentrations ranging from controls to very heavily contaminated, all at the same site. Such a study cannot be realized at a mercury contaminated area or under laboratory conditions, but could be achieved by introducing methylmercury into breeding females and allowing them to deposit mercury in their eggs. Female mallards (Anas platyrhynchos) were intraperitoneally injected with solutions of methylmercury chloride dissolved in corn oil, propylene glycol, dimethyl sulfoxide, mineral oil, Olestra, Crisco, lard, hard paraffin, and a combination of hard and soft paraffin. In some cases, egg laying was delayed, either due to the solvent itself (in the case of Olestra, Crisco, and lard) or to the highest concentration of methylmercury chloride (500 ug/g) in some of the solvents. Mercury in eggs ranged from a control level (<0.1 ug/g) to approximately 14 ug/g on a wet weight basis, which more than covers the range of concentrations reported in wild bird eggs. Mercury concentrations in a series of eggs from the same female declined mostly due to excretion of mercury in prior eggs and not because of the length of time since the injection. Intraperitoneal injections hold promise in field studies where one would like to study the reproductive effects of a wide range of methylmercury levels in the eggs of a wild bird and under the natural conditions that exist in the field.

For more Ecotoxicity Excerpts (Complete) data for Methylmercuric chloride (10 total), please visit the HSDB record page.

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

Mercury is an element, and therefore its chemical structure cannot be further broken down. In its elemental form, mercury is highly toxic when inhaled. Therefore, incineration of mercury is not recommended as a disposal method. Mercury-containing waste products include waste effluents from chloralkali plants and discarded mercury-containing mechanical and electrical devices ... Under current federal guidelines, mercury and its compounds are considered hazardous substances, and various regulations are in effect to control the emission of mercury into the environment (especially organic compounds) ... Emissions from mercury ore processing facilities and mercury cell chloralkali plants are limited to 2.3 kg/day/facility. Emissions of mercury from the incineration or drying of wastewater sludges is limited to 3.2 kg/day/facility ... In addition, dumping wastes containing more than trace amounts of mercury is prohibited. Recycling of mercury-containing compounds is an important method of disposal. Recycling (retorting) is a treatment for five categories of mercury wastes including: (D009) characteristic mercury; (K106) chloralkali waste; (P065) mercury fulminate; (P092) phenylmercuric acetate; and (U151) elemental mercury ... From 1987 to 1991, annual production of mercury from old scrap averaged nearly 180 metric tons, equivalent to 16% of the average reported consumption during that period (Jasinski 1993). Virtually all mercury can be reclaimed from mercury cell chloralkali plants, electrical apparati, and control instruments when plants are dismantled or scrapped ... Increased recycling would decrease the mercury load from waste sites and treatment plants. As environmental concerns increase with respect to the disposal of mercury, the recovery by recycling and industrial processes will become a more significant source of domestic supply ...

PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/

PRECAUTIONS FOR "CARCINOGENS": ... Incineration may be only feasible method for disposal of contaminated laboratory waste from biological expt. However, not all incinerators are suitable for this purpose. The most efficient type ... is probably the gas-fired type, in which a first-stage combustion with a less than stoichiometric air:fuel ratio is followed by a second stage with excess air. Some ... are designed to accept ... aqueous & organic-solvent solutions, otherwise it is necessary ... to absorb soln onto suitable combustible material, such as sawdust. Alternatively, chem destruction may be used, esp when small quantities ... are to be destroyed in laboratory. /Chemical Carcinogens/

For more Disposal Methods (Complete) data for Methylmercuric chloride (7 total), please visit the HSDB record page.

/GUIDE 151: SUBSTANCES - TOXIC (NON-COMBUSTIBLE)/ Health: Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. /Mercury compounds, solid, n.o.s./

/GUIDE 151: SUBSTANCES - TOXIC (NON-COMBUSTIBLE)/ Fire or Explosion: Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Containers may explode when heated. Runoff may pollute waterways. /Mercury compounds, solid, n.o.s./

/GUIDE 151: SUBSTANCES - TOXIC (NON-COMBUSTIBLE)/ Public Safety: CALL Emergency Response Telephone Number ... As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at lease 25 meters (75 feet) for solids. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. /Mercury compounds, solid, n.o.s./

/GUIDE 151: SUBSTANCES - TOXIC (NON-COMBUSTIBLE)/ 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. /Mercury compounds, solid, n.o.s./

For more DOT Emergency Guidelines (Complete) data for Methylmercuric chloride (8 total), please visit the HSDB record page.

PRECAUTIONS FOR "CARCINOGENS": When no regulations exist, the following procedure must be adopted. The carcinogen should be enclosed in a securely sealed, watertight container (primary container), which should be enclosed in a second, unbreakable, leakproof container that will withstand chem attack from the carcinogen (secondary container). The space between primary & secondary container should be filled with absorbent material, which would withstand chem attack from the carcinogen & is sufficient to absorb the entire contents of the primary container in the event of breakage or leakage. Each secondary container should then be enclosed in a strong outer box. The space between the secondary container & the outer box should be filled with an appropriate quantity of shock-absorbent material. Sender should use fastest & most secure form of transport & notify recipient of its departure. If parcel is not received when expected, carrier should be informed so that immediate effort can be made to find it. Traffic schedules should be consulted to avoid ... arrival on weekend or holiday ... /Chemical Carcinogens/

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/