The search for the methods of detoxication is a keydirection in modern ecology and biotechnology. One ofthe possible ways of detoxication of pollutants may bethe use of humic substances—the products of naturaltransformation of various organic substances. Today,more and more data on the ability of humic substancesto decrease the detrimental influence of toxicantsappear [1, 2]. Earlier, the effect of detoxication wasstudied using classic test systems, such as fish, algae,crustaceans, and plants [2–6].However, despite the long-term experience of study-ing the properties of humic substances, the question onthe mechanism of the detoxicating effect of humic sub-stances remains open. It was assumed that the detoxi-cating properties of humic substances are determinedby their ability to reduce oxidants. The presence inhumic substances of phenolic groups and fragmentscarrying unpaired electrons allows to assume the possi-bility of transition (in particular, bivalent mercury) intoreduced and, respectively, less toxic forms upon inter-action with humic substances [7, 8]. It was alsoassumed that toxicants are bond by humic substances,which prevents penetration of such large aggregatesinto cells [9].To study the mechanisms of detoxication of toxi-cants by humic substances in detail, simple test systems(such as luminous bacteria) are especially promising.They have great advantages over the biotests that wereused earlier due to high rate of analysis, sensitivity,simplicity, and possibility of instrumental recording oftoxicity.This study is devoted to investigation of the mecha-nism of detoxication of solutions of organic oxidantsusing humic substances. Quinones—the products ofoxidation of the very widely spread organic pollutants,phenols, were chosen as model organic substances.MATERIALS AND METHODSIn this study, we used a series of quinones with dif-ferent redox characteristics: 1,4-benzoquinone, tet-rafluoro-1,4-benzoquinone, methyl-1,4-benzoquinone,tetramethyl-1,4-benzoquinone, and 1,4-naphto-quinone.The toxicity of quinones was assessed using thebioluminescence biotest Microbiosensor 677F [10],which is based on lyophilized luminous bacteria