Editing Creosote (section)

===Oxidation-reduction===
Even though many studies conduct testing under experimental or enriched conditions, [[redox|oxidation-reduction reactions]] occur naturally and allow for chemicals to go through processes such as biodegradation, outlined above. Oxidation is defined as the loss of an electron to another species, while reduction is the gaining of an electron from another species. As compounds go through oxidation and reduction in sediments, the preservative compounds are altered to form new chemicals, leading to decomposition. An example of the oxidation of p-cresol and phenol can be seen in the figures below:

====p-Cresol====
[[File:P-cresol degradation to benzoate.png|frameless|upright=2.25]]

This reaction shows the oxidation of p-cresol in a sulfate-enriched environment.<ref name="Smolenski"/> P-cresol was seen to be the easiest to degrade through the sulfate-enriched environment, while m-cresol and o-cresol where inhibited.<ref name="Smolenski"/> In the chart above, p-cresol was oxidized under an anaerobic sulfate reducing condition and formed four different intermediates.<ref name="Smolenski"/> After the formation of the intermediates, the study reported further degradation of the intermediates leading to the production of carbon dioxide and methane.<ref name="Smolenski"/> The p-hydroxylbenzyl alcohol, p-hydroxylbenzaldehye, p-hyrdoxylbenzoate, and benzoate intermediates all are produced from this oxidation and released into the sediments.<ref name="Smolenski"/> Similar results were also produced by different studies using other forms of oxidation such as: iron-reducing organisms,<ref name=Lovley1990/> Copper/Manganese Oxide catalyst,<ref name=wang2004/> and nitrate- reducing conditions.<ref name=Bossert1986/>

====Phenol====
[[File:Phenol reaction with iron and peroxide.png|frameless|upright=1.5]]

This reaction shows the oxidation of phenol by iron and peroxide.<ref name="Zazo et al 2005"/> This combination of iron, which comes from iron oxide in the sediment, and the peroxide, commonly released by animals and plants into the environment, is known as the [[Fenton reaction|Fenton Reagent.]]<ref name="Zazo et al 2005"/> This reagent is used to oxidize phenol groups by the use of a radical hydroxide group produced from the peroxide in the p-benzoquinone.<ref name="Zazo et al 2005"/> This product of phenol's oxidation is now leached into the environment while other products include iron(II) and water. P-benzoquinone is listed as being a very toxic, acute environmental hazard.<ref>{{cite web |title=Quinone |website=PubChem Database |publisher=National Center for Biotechnology Information |url=https://pubchem.ncbi.nlm.nih.gov/compound/p-benzoquinone |access-date=April 7, 2019}}</ref>