Toxic nitrophenols

Toxic nitrophenols (4-nitrophenol, 2-nitrophenol, and 2,4-dinitrophenol) present in air samples are sampled on silica gel or XAD-2 polymeric resin, extracted, and analyzed by the HPLC/DAD technique [240], Nitrophenols are also determined in rain and snow precipitations through HPLC/ UV analysis after SPE [241]. 

Belloli, R., B. Barletta, E. Bolzacchini, S. Meinardi, M. Orlandi and B. Rindone, Determination of toxic nitrophenols in the atmosphere by high-performanee Hquid chromatography, J. Chromatogr. A, 846 (1999), 277-281. 

Dinitrophenol is another highly toxic phenolic compound. All nitrophenols are toxic. Nitrophenols containing more than three nitro groups are unstable, the toxicity of which has not been invesdgated. 

The rat LD qS are 13, 3.6 (oral) and 21, 6.8 (dermal) mg/kg. Parathion is resistant to aqueous hydrolysis, but is hydroly2ed by alkah to form the noninsecticidal diethjlphosphorothioic acid and -nitrophenol. The time required for 50% hydrolysis is 120 d ia a saturated aqueous solution, or 8 h ia a solution of lime water. At temperatures above 130°C, parathion slowly isomerizes to 0,%diethyl 0-(4-nitrophenyl) phosphorothioate [597-88-6] which is much less stable and less effective as an insecticide. Parathion is readily reduced, eg, by bacillus subtilis ia polluted water and ia the mammalian mmen to nontoxic 0,0-diethyl 0-(4-aminophenyl) phosphorothioate, and is oxidized with difficulty to the highly toxic paraoxon [511-45-5] diethyl 4-nitrophenyl phosphate d 1.268, soluble ia water to 2.4 mg/L), rat oral LD q 1.2 mg/kg. 

SUBSTITUTED NITROPHENOL PESTICIDES, LIQUID, FLAMMABLE, TOXIC, 3013 ... 

Often, absorption occurs by multiple routes in humans. Dean et al. (1984) reported deaths and toxic effects as well as lowered blood cholinesterase levels and excretion of urinary 4-nitrophenol in several children who were exposed by inhalation, oral, and possibly dermal routes after the spraying of methyl parathion in a house. In the same incident (Dean et al. 1984), absorption was indicated in adults who also excreted 4-nitrophenol in the urine, though at lower levels than some of the children, and in the absence of other evidence of methyl parathion exposure. In this study, the potential for age-related differences in absorption rates could not be assessed because exposure levels were not known and the children may have been more highly exposed than the adults. Health effects from multiple routes are discussed in detail in Section 3.2. 

Most of the toxic effects caused by methyl parathion resulted from exposure by multiple routes, especially for workers in sprayed fields or formulating facilities, or people in homes. Dean et al. (1984) reported deaths and toxic effects in several children as well as lowered blood cholinesterase levels and excretion of urinary 4-nitrophenol (adults showing no adverse effects also excreted 4-nitrophenol). 

It is important to emphasize that the initial metabolites after hydrolysis may be both toxic and sometimes resistant to further degradation. Examples include nitrophenols, whose degradation is discussed in Chapter 9, Part 5 and 3,5,6-trichloropyridin-2-ol (Feng et al. 1997), which is produced by the hydrolysis of chlorpyrifos (0,0-diethyl-0-[3,5,6-trichlo-2-pyridyl]phosphorothioate). 

Use of PEG-phenylcarbonate derivatives for preparation of urethane-linked PEG-proteins was reported (75). The main drawback of this approach lies in the toxicity of hydrophobic phenol residues (p-nitrophenol or 2,4,5-trichlorophenol) and their affinity to proteins. 

Wash effluents from nitration installation can cause problems due to the high nitrophenol concentrations, their high toxicity to sewage bacteric and their general resistance to biodegradation. Electrochemical pretreatment tests in the laboratory showed a reduction in toxicity, and improvement of the color smell, etc. The electrochemical pretreatment is also attractive because of the absence of solid waste coproducts and its ease of operational control, [135]. 

Lech, J. J., Statham, C. N. Role of glucuronide formation in the selective toxicity of 3-trifluoromethyl-4-nitrophenol (TFM) for the sea lamprey comparative aspects of TFM uptake and conjugation in sea lamprey and rainbow trout. Toxicol. Appl. Pharmacol. (1975), 37(1) 150-158. 

The phenolic functional group consists of a hydroxyl attached directly to a carbon atom of an aromatic ring. The OH group can also be the consequence of further oxidation or combination with other pollutants such as pesticides, aldehydes, and alcohols (i. e., 2,4-D, cyclic alcohols, cresols, naphthols, quinones, nitrophenols, and pentachlorophenol compounds) forming new more toxic compounds [17,42,160]. 

Brecken-Folse.l.A.. Mayer. F.L.. Pedigo. L.E.. and Marking. L.L. Acute toxicity of 4-nitrophenol. 2.4-dinitrophenol.terbufos and trichlorfon to grass shrimp (Palaemonetes spp.) and sheepshead minnows (Cyprinodon variegatosf as affected by salinity and temperature. Environ. ScL Technol, 13(l) 67-77.1994. 

Ingestion of alcohol aggravates the toxic effects of nitrobenzene. In general, higher ambient temperatures increase susceptibility to cyanosis from exposure to methemoglobin-forming agents." p-Nitrophenol and p-aminophenol are metabolites of nitrobenzene, and their presence in the urine is an indication of exposure."... 

Substituted nitrophenol pesticides, liquid, flammable, toxic, n.o.s., flash point less than 23 degrees C 2780... 

Mills and Hoffmann (1992) investigated ultrasonic degradation of parathion. Parathion (0,0-diethyl O-p-nitrophenyl triphosphate) is a major pesticide used in large quantities worldwide. Organophosphate esters such as parathion have been used as alternatives to DDT and other chlorinated hydrocarbon pesticides however, the organophosphate esters are not rapidly degraded in natural waters. At 20°C and pH 7.4, parathion has a hydrolytic half-life of 108 days and its toxic metabolite, paraoxon, has a similar half-life of 144 days. Ultrasonic irradiation of 25 mL of parathion-saturated, deionized water solution was conducted in a water-jacketed, stainless-steel cell with a Branson 200 sonifier operating at 20 kHz and 75 W/cm2. The temperature of the sonicated solution was kept constant at 30°C. All sonolytic reactions were carried out in air-saturated solution. The concentration of the parathion hydrolysis product p-nitrophenol (PNP) was determined in alkaline solution with a Shimadzu MPS-2000 UV /visible spectrophotometer. 

The extreme toxicities of the nitrophenolic herbicides probably accounts for the paucity of teratogenic studies in this class of herbicides. Rat studies of the related hair dyes 1,2- and 1,4-diaminonitrobenzenes revealed extensive reproductive anomalies. 

Nitro alcohols are nonaromatic compounds containing both -OH and -N02 groups. A typical example of such a compound is 2-nitro-l-butanol, shown below. These compounds are used in chemical synthesis to introduce nitro functional groups or (after reduction) amino groups onto molecules. They tend to have low volatilities and moderate toxicities. The aromatic nitrophenol, / -nitrophenol, is an industrially important compound with toxicological properties resembling those of phenol and nitrobenzene. 

Dinoseb is a nitrophenolic compound, once widely used as an herbicide and plant desiccant, that is noted for its toxic effects. The chemical name of this compound is 4,6-dinitro-2-,v< o butylphenol, and its structure is... 

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