Solvents acute

Toxicology. The nitroparaffins have minimal effects by way of actual contact. There were neither systemic effects nor irritation in dermal studies in rabbits. Human exposure of a prolonged or often-repeated nature has led to low grade irritation attributable to removal of oil from the skin, an effect produced by most organic solvents. Eye irritation potential of all four nitroparaffins has been deterrnined in rabbits. Other than a transient slight redness and some lachrymation, no effects were noted. The average Draize score was 0.0. The acute oral toxicity, LD q, of all four nitroparaffins has been deterrnined in the rat (Table 8). 

Health and Safety Factors. Animal-feeding studies of DMPPO itself have shown it to be nontoxic on ingestion. The solvents, catalyst, and monomers that are used to prepare the polymers, however, should be handled with caution. Eor example, for the preparation of DMPPO, the amines used as part of the catalyst are flammable toxic on ingestion, absorption, and inhalation and are also severe skin and respiratory irritants (see Amines). Toluene, a solvent for DMPPO, is not a highly toxic material in inhalation testing the TLV (71) is set at 375 mg/m, and the lowest toxic concentration is reported to be 100—200 ppm (72). Toxicity of 2,6-dimethylphenol is typical of alkylphenols (qv), eg, for mice, the acute dermal toxicity is LD q, 4000 mg/kg, whereas the acute oral toxicity is LD q, 980 mg/kg (73). The Noryl blends of DMPPO and polystyrene have PDA approval for reuse food apphcations. 

In a cross-sectional study, exposure and effect are studied simultaneously. This approach contains an inherent problem because exposure must precede the effect. However, it can he used to investigate acute effects and also mild chronic effects (which do not force people to leave their jobs) if exposure has remained rather stable for a long time. When the prevalence of the effects studied are compared with the prevalence in other worker groups (controls or references) which correspond otherwise with the study group but are not exposed to the agent investigated, indicative evidence of possible causality may be obtained. For example, cross-sectional studies have been applied successfully to reveal the associations between mild neurotoxic effects and exposure to organic solvents. ... 

Many very hazardous solvents, such as benzene and carbon tetrachloride, were widely used until the 1970s. The situation was very similar for the use of pesticides. Among the toxic pesticides that were still in wide use 20 years ago were chlorophenols, DDT, lindane, and arsenic salts, all of which are classified as human carcinogens as well as being acutely toxic. Fortunately, use of these kinds of very toxic chemicals is now limited in the industrialized world. However, because the number of chemicals used in various industries continues to increase, the risks of long-term health hazards due to long-term exposure to low concentrations of chemicals continues to be a problem in the workplace. 

Organic solvents have acute narcotic effects. Aromatic and chlorinated hydrocarbons seem to be especially effective. As stated, the combined effect of several organic solvents is usually considered to be additive. However, there is some evidence that the combined effect may in fact be synergistic. The symptoms caused by organic solvents, often called prenarcotic symptoms, resemble those caused by the use of alcohol. A decrease in reaction time and impairment in various psychological performances can be observed. Acute neurotoxicity can also be detected as abnormalities in the electroencephalogram (EEG i, which records the electrical activity of the brain. " ... 

Toxic Reactions of the Skin Irritation is the most common reaction of the skin. Skin irritation is usually a local inflammatory reaction. The most common skin irritants are solvents dehydrating, oxidizing, or reducing compounds and cosmetic compounds. Acids and alkalies are common irritants. Irritation reactions can be divided into acute irritation and corrosion. Necrosis of the surface of the skin is typical for corrosion. Acids and alkalies also cause chemical burns. Phenols, organotin compounds, hydrogen fluoride, and yellow phosphorus may cause serious burns. Phenol also causes local anesthesia, in fact it has been used as a local anesthetic in minor ear operations such as puncture of the tympanous membrane in cases of otitis. ... 

The problem of the isolation of quaternary salts, even when fornied, is,-in some cases, an acute one. Water or ethanol is friBquently held very tenaciously and this possibility may be the reason that so many workers still use non-hydrie solvents, such as benzene, despite the fact that reactions in such solvents are usually slow clearly the best solvents are the non-hydric ones of high dielectric constant. 

Inhalant intoxication dehrium can occur as a consequence of disturbances in dopaminergic, glutamatergic, and GABAergic neu to transmission secondary to acute, high-level exposure to psychoactive ingredients in solvents such as toluene, trichloroethane, and trichloroethylene. Systemic effects of solvent inhalation such as cerebral hypoxia and/or metabolic acidosis may also be involved (Rosenberg 1982). Under these circumstances, inhalant intoxication dehrium develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day. Usually, the delirium resolves as the intoxication ends or within a few hours after cessation of use. 

Liquid PCP often contains volatile solvents that impart an "etherlike" odor to the patient, although PCP itself is odorless. PCP is nonvolatile at room temperatures, but ether is highly volatile. Undoubtedly, some of the acute reactions that occur after exposure to street "PCP fumes"1 are due to the effects of the ether and not to PCP. Several reactions of this type have been observed, such... 

Over the past two decades, the pharmaceutical community has become acutely aware that many substances of interest can be obtained in more than one crystal form, and that the properties of these solids may often be quite different. Polymorphism is the term used to denote crystal systems where a substance can exist in different crystal packing arrangements, but all of which are characterized by exactly the same elemental composition. Other crystal variations are known where a given substance exists in different crystal packing arrangements, but each of which exhibits a different elemental composition. Since this latter phenomenon usually involves the inclusion of one or more solvent molecules in the crystal, the term solvatomorphism has been coined to replace the inconsistent nomenclature used over the years. These and related phenomena have been the focus of several recent monographs [1-3],... 

In addition to the chemicals included on the other lists, the CDC also included heavy metals such as arsenic, lead, and mercury volatile solvents such as benzene, chloroform, and bromoform decomposition products such as dioxins and furans polychlorinated biphenyls (PCBs) flammable industrial gases and liquids such as gasoline and propane explosives and oxidizers and all persistent and nonpersistent pesticides. Agents included in this volume are limited to those that are most likely to pose an acute toxicity hazard. 

Reactants and reagents can be conveniently loaded into the dry zeolite by adsorption. This can be accomplished by intimately mixing the solid or liquid reactant and the powdered zeolite, by absorption from the gas phase, or by diffusion in a solvent slurry containing the zeolite and dissolved reactant. The choice of solvent for the slurry method is critical. It must be volatile enough to be removable at a pressure and temperature that does not result in evacuation of the reactant or its decomposition. In addition, the reactant must have a greater affinity for the interior of the zeolite than for the slurry solvent itself. The lack of affinity for the interior of the zeolite is an acute problem for non-polar hydrocarbons that lack binding sites for the intrazeolitic cations. The use of fluorocarbons such as perfluorohexane as slurry solvents takes advantage of the fluorophobicity of many hydrocarbons and has alleviated this problem to some extent.29... 

---