Creosote toxicity

Medicinal creosote is a mixture of phenols, chiefly guaiacol and creosol (4-melhyl-2-meth-oxyphenol), obtained by distillation of wood tar. B.p. 480-500 K. It is almost colourless with a characteristic odour and is a strong antiseptic, less toxic than phenol. 

Creosote is a complex mixture of toxic chemicals, which can have both immediate and chronic effects on exposed organisms. PIC of creosote are of particular concern due to long half-lives of some chemicals, and because of multiple pathways to the environment from ash and soot. 

Use of some biomass feedstocks can increase potential environmental risks. Municipal solid waste can contain toxic materials that can produce dioxins and other poisons in the flue gas, and these should not be burned without special emission controls. Demolition wood can contain lead from paint, other heavy metals, creosote, and halides used in presen a-tive treatments. Sewage sludge has a high amount of sulfur, and sulfur dioxide emission can increase if sewage sludge is used as a feedstock. 

Malins DC, MM Krahn, MS Myers, LD Rhodes, DW Brown, CA Krone, BB McCain, S-L Chan (1985) Toxic chemicals in sediments and biota from a creosote-polluted harbor relationships with hepatic neoplasms and other hepatic lesions in English sole (Parophrys vetulus). Carcinogenesis 6 1463-1469. 

Chemicals degraded by WRF include pesticides such as organochlorines DDT and its very toxic metabolite DDE [8, 9] and organophosphate pesticides such as chlorpyrifos, fonofos and terbufos [10] polychlorinated biphenyls (PCBs) of different degrees of chlorine substitution [11-13], some even to mineralization [14, 15] diverse polycyclic aromatic hydrocarbons (PAHs) in liquid media and from contaminated soils or in complex mixtures such as creosote [16-18] components of munition wastes including TNT and its metabolites DNT [19-23], nitroglycerin [24] and RDX [25]. 

As this table suggests, the environmental hazard posed by heavy metals varies significantly. Some of the elements listed in that chart are among the most hazardous substances released to the environment. The EPA has classified four of the heavy metals—arsenic, lead, mercury, and cadmium—among the top 25 most hazardous chemicals present in the environment in the United States. (Of the remaining substances on that list 18 are toxic organic chemicals one is another heavy metal, chromium one is white phosphorus and the last is creosote produced from coal tar.)... 

Pyridine and its homologues are produced in coking procedures and present in the non-condensable gases. Pyridine is also present in coal-tar and as a component in creosote (Agency for Toxic Substances Disease Registry, 1992 Dutch Ministry of Social Affairs and Employment, 1993). 

Hyotylainen, T. and Oikari, A. (1999) The toxicity and concentrations of PAHs in creosote-contaminated lake sediment, Chemosphere 38 (5), 1135-1144. 

A.J. Arieff, Acute, toxic, polioencephalitis (creosote). JAMA. 193 745, 1965. 

Creosote from coal tar is the most widely used wood preservative for several reasons (1) it is highly toxic to wood-destroying organisms (2) it has a high degree of permanence due to its relative insolubility in water and its low volatility (3) it is easily applied, with deep penetration easily obtained and (4) it is relatively cheap and widely available. For general outdoor service in structural timbers, poles, posts, piling, and mine props, and for marine uses, coal-tar creosote is the best and most important preservative. Because of its odor, dark color, and the fact that creosote-treated wood usually cannot be painted, creosote is unsuitable for finished lumber and for interior use. 

Often coal tar or petroleum oil is mixed with coal-tar creosote, in amounts up to 50 percent, as a means of lowering preservative costs. Because coal tar and petroleum have a low toxicity, their mixtures with creosote are less toxic than is creosote alone. 

Ahtiainen, J., Valo, R., Jarvinen, M. Joutti, A. (2002). Microbial toxicity tests and chemical analysis as monitoring parameters at composting of creosote-contaminated soil. Ecotoxicology and Environmental Safety, 53, 323-9. 

Fig. 29.15 Chronic toxic hepatitis after 10 months chaparral ( creosote bush ) automedication. Laparoscopy marked acinar structure, irregular chagreen-like surface (splintered light reflex) and extremely fine fibrosis histology single cell necrosis, slight inflammatory infiltrations and moderate steatosis...

The wood-preservative properties of creosote depend upon many factors and, whilst the tar acids are good fungicides, they are also the components, which are most susceptible to loss from wood by volatilisation and leaching (3). Due to the relatively high toxicity of creosote based predominantly on the presence of ben2o[a]pyrene (b[a]p), there exist special regulations and restrictions within the EU and in some member states such as Sweden, Demnark, Austria, Germany, and the Netherlands (4). 

Nencki introduced salol in 1886 and. so pre.sented to the science of therapy the "salol principle." In salol. two toxic sub.stances (phenol and salicylic acid) were combined into an e.ster that taken internally slowly hydroly/es in the intestine to give the antiseptic action of its components. This type of ester is referred to as a full. salol or true salol when toth components of the ester are active compounds. Examples are guaiacol benzoate. /3-naphthol benzoate, and salol. The salol principle can be applied to esters in which only the alcohol or the acid is the toxic, active or corrosive portion this type is called a partial salol. Examples of partial sulols that contain an active acid arc ethyl salicylate and methyl salicylate. Examples of partial sulols that contain an active phenol are creosote carbonate, thymol carbonate, and guaiacol carbonate. Althtxigh many. salol-typc compounds have been prepared and used tu. some extent, none is presently... 

Hydrocarbon compounds such as fuels, lubricating oils and creosote contain toxic components. Naphthalene and its methyl-substituted derivatives are some of the most acutely toxic, water-soluble components of crude oils. As the molecular size of hydrocarbons increases, their lipophilicty, environmental persistence and mutagenicity also increase. Many chemicals represent classes of molecules not previously investigated, some have no close structural analogs in nature, and there are those that were intentionally developed to be resistant to microbial attack and to persist in nature. 

Toxicity is expressed either via general depression with cardiac collapse or via the irritating/corrosive nature by irritation and burns of the skin and eyes. Brief exposures via inhalation may cause respiratory irritation. Oral exposure to larger quantities of creosote may result in stomach pains and burning of the mouth. Large doses (7g for adults and 1-2 g for children) have been associated with death 14-17 h after ingestion. Cardiovascular collapse appears to be the primary cause of death. Nonlethal symptoms include salivation, vomiting, thready pulse. 

Creosote is highly toxic to aquatic organisms with typical acute values of 76ppb for Daphnia magna (48 h LC50) and 600 ppb for rainbow trout (96 h LC50). 

Zemanek MG, Pollard SJ, Keneflck SL, Hrudey SE. Toxicity and mutagenicity of component classes of oils isolated from soils at petroleum- and creosote-contaminated sites. J Air Waste Manag Assoc 1997 47(12) 1250-8. 

A 57-year-old man who had spent 41 years as a painter was disabled and forced to retire. He was diagnosed with chronic toxic encephalopathy. The man started work as a painter at the age of 16. He started experiencing impaired short-term memory function while in his forties. His condition progressed until he retired and his exposures to the paint solvents ceased. Following his retirement, his condition stabilized and even improved in some areas. Material safety data sheets provided by his employer indicated that this man had been exposed to lead, titanium dioxide, creosote, and the following volatile solvents ... 

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