Absorption, skin

Sodium trichloroacetate [650-51-17, C2Cl202Na, is used as a herbicide for various grasses and cattails (2). The free acid has been used as an astringent, antiseptic, and polymerisation catalyst. The esters have antimicrobial activity. The oral toxicity of sodium trichloroacetate is quite low (LD q rats, 5.0 g/kg). Although very corrosive to skin, trichloroacetic acid does not have the skin absorption toxicity found with chloroacetic acid (28). 

The alcohols are toxic orally, through skin absorption, and through inhalation. The secondary alcohols are more toxic than the tertiary. The glycols are relatively low in toxicity. 

Acrolein is highly toxic by skin absorption. Brief contact may result in the absorption of harmful and possibly fatal amounts of material. Skin contact causes severe local irritation and chemical bums. Poly(vinyl chloride) coated protective gloves should be used (99). 

The acute toxicity of DMF is relatively low. The LD q by oral ingestion ia rats is 2800 mg/kg and the LC for mice is 9400 mg/(2 h). Skin absorption is also an important route by which DMF can be iatroduced iato the body, and an LD q of 4720 mg/kg has been observed ia rabbit-skia exposure studies. 

Ceiling value and skin absorption special measures to prevent significant cutaneous absorption may be required. 

Strong acids and strong alkaUes can severely bum the skin, chromium compounds can produce skin rashes, and repeated exposure to solvents causes removal of natural oils from the skin. Infection is always a concern for damaged skin. Absorption through the skin is possible for materials that are appreciably soluble iu both water and oil, eg, nitrobenzene, aniline, and tetraethyllead. Other materials can be absorbed if first dissolved iu extremely good solvents, eg, dimethyl sulfoxide. Subcutaneous iujection can occur accidentally by direct exposure of the circulatory system to a chemical by means of a cut or scratch or iuadvertent penetration of the skin with a hypodermic needle. 

Health and Safety Factors. Neopentanoic acid possesses low toxicity, either by ingestion (oral LD q in rats is 2.0 g/kg) or by skin absorption (dermal LD q in rabbits is 3.16 g/kg). The principal ha2ards associated with neopentanoic acid at ambient temperatures are from eye and skin irritation. At elevated temperatures, where concentrations of the vapor are significant, irritation of the respiratory tract can also occur. Contact with the material should be avoided. 

AHyl chloride is toxic through Hquid contact with the skin and can cause severe irritation, resulting in deep-seated pain and delayed bums. Effects may be more severe in instances where Hquid is confined to the skin. The LD q for toxicity through skin absorption in rabbits is 400—2200 mg/kg body weight (24,50). Contact with the eyes can cause permanent eye injury, even blindness. 

Because of the nature of some applications in which chlorinated paraffins are used, skin contact is inevitable and therefore an important potential route into the body. Skin absorption studies (7) have shown that chlorinated paraffins are very poorly absorbed through the skin and should not cause significant systemic concentrations. 

Skin Absorption. Normal skin absorbs HCN slowly. However, 2% HCN in air may cause poisoning in 3 min, 1% is dangerous in 10 min, and 0.05% may produce symptoms after 30 min, even though a gas mask or air mask is worn. Some areas of the body, such as the feet and mucous membranes, are more absorptive than others. Cuts and abrasions absorb cyanide rapidly, and 50 mg of HCN absorbed through the skin can be fatal. 

Notify a physician immediately. A suggested procedure for physicians or nurses is intravenous administration of 0.3 g (10 mL of a 3% solution) of sodium nitrite at the rate of 2.5 mL/min followed by 12.5 g (50 mL of a 25% solution) of sodium thiosulfate at the same rate. Watch the patient for 24 to 48 h, especially in cases of ingestion or skin absorption. If symptoms reappear, repeat the injections in half the original amounts. These solutions should be kept readily available. In some cases, first aid personnel have been trained to use the intravenous medication subject to government regulations. 

Cyanohydrins are highly toxic by inhalation or ingestion, and moderately toxic through skin absorption (21). AH a-hydroxy nitriles are potential sources of hydrogen cyanide or cyanides and must be handled with considerable caution. Contact with the skin and inhalation should be rigorously avoided. Special protective clothing should be worn and any exposure should be avoided (18,20). The area should be adequately ventilated. Immediate medical attention is essential in case of cyanohydrin poisoning. 

The ACGIH threshold limit value (TLV), time-weighted average for an 8 hour workday, 40 hour workweek, was set at 50 ppm (- 200 mg/m ) with a notation for skin absorption (29). 

Toxicological studies conducted on DCPD indicate that it is a moderately toxic material and, to some extent, an irritant and a narcotic. By oral administration in the rat, the LD q is 0.82 g/kg of body weight, and by skin absorption in the rabbit, the LD q is 6.72 ml,/kg. An atmospheric concentration of 2000 ppm causes death in rats exposed for a period of 4 hours. 

Toxic chemicals can enter the body in various ways, in particular by swallowing, inhalation and skin absorption. Skin absorption may lead to dermatitis and this can be a most annoying complaint. Whereas some chemicals may have an almost universal effect on human beings, others may attack only a few persons. A person who has worked with a given chemical for some years may suddenly become sensitised to it and from then on be unable to withstand the slightest trace of that material in the atmosphere. He may as a result also be sensitised not only to the specific chemical that caused the initial trouble but to a host of related products. Unfortunately a number of chemicals used in the plastics industry have a tendency to be dermatitic, including certain halogenated aromatic materials, formaldehyde and aliphatic amines. 

The LD50 is the statistically derived single dosage of a substance that can be expected to cause death in 50% of the sample population. It is therefore an indicator of acute toxicity, usually determined by ingestion using rats or mice, although other animals may be used. LD50 is also determined by other routes, e.g. by skin absorption in rabbits. The values are affected by species, sex, age, etc. 

For most ehemieals, inhalation is the main route of entry into the body. Penetration via damaged skin (e.g. euts, abrasions) should, however, be avoided. Certain ehemieals (e.g. phenol, aniline, eertain pestieides) ean penetrate intaet skin and so beeome absorbed into the body. This may oeeur through loeal eontamination, e.g. from a liquid splash, or through exposure to high vapour eoneentrations. Speeial preeautions to avoid skin eontaet are required with these ehemieals and potential exposure via skin absorption has to be taken into aeeount when assessing the adequaey of eontrol measures. 

A good standard of personal hygiene is required to minimize exposure by ingestion or skin absorption of chemicals. The measures include ... 

Acrylonitrile (Vinyl cyanide) CH,CHCN Closely resembles HCN in toxic action Poisonous by inhalation, ingestion or skin absorption Emits cyanides when heated or contacted by acids or acid fumes Symptoms flushed face, irritation of eyes and nose, nausea etc. Colourless flammable liquid with mild, faintly pungent odour Elash point 0°C. Dilute water solutions also have low flash points... 

Potassium cyanide KCN On exposure to air, gradually decomposes to release HCN Poisonous by ingestion, inhalation or skin absorption Do not handle with bare hands. Strong solutions may be corrosive to the skin Nonflammable white lumps or crystals Eaint odour of bitter almonds Completely water soluble... 

Sodium cyanide NaCN Poisonous by inhalation, ingestion or skin absorption Do not handle with bare hands Releases HCN slowly with water, more rapidly with acids Nonflammable white granules, fused pieces or eggs Odourless when dry slight almond odour in damp air Completely water soluble... 

The Occupational Exposure Standards imposed for trichloroethylene are Maximum Exposure Limits of 100 ppm (8 hr TWA) and 150 ppm (15 minute reference period). A skin notation Sk is applicable because of the potential for skin absorption. Because of its volatility, trichloroethylene is not recommended for cold cleaning it is normally used in partially enclosed vapour degreasing equipment provided with local exhaust ventilation. 

Impervious clothing is essential when handling coiTosive chemicals, liquids liable to cause dermatitis, or chemicals toxic by skin absorption. 

Chemical PPE In a fire or thermal energy hazard, PPE worn by responders should meet, at a minimum, the criteria in 29 CER 1910.156 (e), Eire Brigade Standard, requiring turnout gear. In conditions where skin absorption of a hazardous substance may result in substantial possibility of immediate death, serious illness, or injury or impaired ability to escape, totally encapsulated chemical protective suits should be used. It is vital to keep heat resistance of the totally encapsulated suits and the heat resistance of any PPE used underneath or in conjunction with the totally encapsulated suits in mind any time there is a thermal hazard. 

Are totally encapsulating chemical protective suits (Level A) used in conditions where skin absorption of a hazardous substance may result in a substantial possibility of immediate death, immediate serious illness or injury, or impair the ability to escape ... 

Phloroglucinol (1,3,5-Trihydroxy benzene, 1,3,5-Trioxy-benzol in Ger). C6H3(OH)3,mw 126.11, white to yellowish crysts mp 200—209° when heated slowly 212—217° when heated rapidly bp, sublimes with decompn. SI sol in w, sol in ale and eth. Combustible. Can be prepd by fusion of resorcinol with caustic soda, or by reduction of trinitrobenzene. It is highly toxic. by ingestion, inhalation and skin absorption, and is a strong irritant to skin and mucous membranes Refs 1) Beil 6,1092, (545) [1075]... 

May irritate damaged skin absorption can occur with effects similar to those via ingestion. 

Therefore, full-face phenol-based peel should always be performed under full cardiopulmonary monitoring. The average lag time for the onset of the arrhythmias was 17.5 min from the beginning of the peel, and they are usually not delayed for more than 30 min after the peel. Cardiac arrhythmias are more common while applying the solution on the thin skin of eyelids. In this area skin absorption is maximal therefore, application should be performed extremely cautiously. If arrhythmia occurs, the application of phenol should be stopped until... 

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