PRINCIPLES OF TOXICOLOGY - Biology East Borneo

404 PROPERTIES AND EFFECTS OF ORGANIC SOLVENTSFigure 16.32 Nitrobenzene.Figure 16.33 Dinitrophenol.confusion, vertigo, nausea, loss of cognition, hyperalgesia, paresthesia, and polyneuritis have beenreported as well as spleen and liver damage. Both the cyanogenic and anemiagenic potential ofnitrobenzene were listed as considerably greater than those of aniline, and the overall potential forproducing the blood effects was second only to that of dinitrobenzene. There is some risk ofreproductive toxicity shown by a decrease in rat fertility following exposure. No genetic toxicity hasbeen noted. Industrially important exposure to nitrobenzene may be evaluated by measurements ofp-nitrophenol, expressed in conjunction with urinary creatinine.Among the six isomers of dinitrophenol (DNP) (see Figure 16.33), the one most commonly usedfor industrial purposes is 2,4-dinitrophenol. The isomers often are kept as a mixture and are involvedin the synthesis of dyestuffs, picric acid, picramic acid, as herbicides, and in the manufacture of thephotographic developers.Local application of DNP causes yellow staining of skin and may cause dermatitis due to eitherprimary irritation or to allergic sensitivity. In general, DNP disrupts oxidative phosphorylation,resulting in increased metabolism, oxygen consumption, and heat production. Acute poisoning ischaracterized by the onset of fatigue, sudden thirst, sweating, and oppression of the chest. There maybe rapid respiration, tachycardia, and a rise in body temperature. In cases of less severe poisoning, thesymptoms may include nausea, vomiting, anorexia, weakness, dizziness, vertigo, headache, andsweating. The onset of effects is rapid, and death or recovery may occur within 1 or 2 days followingmassive exposure. Chronic exposure may result in kidney and liver damage and in cataract formation.While no federal standards have been set for dinitrophenol, an exposure limit of 0.2 mg/m 3 has beensuggested on the basis of data for dinitro cresol.16.16 TOXIC PROPERTIES OF REPRESENTATIVE NITRILES (ALKYL CYANIDES)The nitriles (e.g., acrylonitrile, acetonitrile) are organic cyanide compounds (see structures in Figure16.34). They are nonpolar and are readily absorbed by all routes. Because some of these compoundsdissociate to produce free cyanide, the adverse effects they produce are comparable to those of cyanide