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22
UDK 621.317.08
DETOXICATION OF PETROCHEMICALS IN SOIL ECOSYSTEMS OF ROADSIDE
AREA
V. Yurchenko, Professor, Doctor of Technical Sciences, Ye. Voronova, Associate Professor L. Mykhailova, magister, KhNAHU
Abstract. During experimental analyses of soil roadside ecological systems there have been revealed concentrations of oil pollution and identified particular petrochemicals. It has been shown that the detoxication of petrochemicals occurs by means of monoterminal reaction. At the researched motorway section, the anthropogenic load does not exceed the possibilities of the natural environment to self-restoration.
Key words: petrochemicals, detoxication, soil of roadside area.
ДЕТОКСИКАЦИЯ НЕФТЕПРОДУКТОВ В ПОЧВЕННЫХ ЭКОСИСТЕМАХ ПРИДОРОЖНОГО ПРОСТРАНСТВА
В.А. Юрченко, профессор, д.т.н., Е.М. Воронова, доцент, Л.С. Михайлова, магистрант, ХНАДУ
Аннотация. В экспериментальных исследованиях почв придорожных экологических систем установлены концентрации нефтяного загрязнения, а также идентифицированы отдельные нефтепродукты. Показано, что детоксикация нефтепродуктов происходит монотерминальным путем. Техногенная нагрузка на исследованном участке не превышает возможности природной среды к самовосстановлению.
Ключевые слова: нефтепродукты, детоксикация, почва придорожного пространства.
ДЕТОКСИКАЦ1Я НАФТОПРОДУКТ1В У Грунтових екосистемах
ПРИДОРОЖНЬОГО ПРОСТОРУ
В.О. Юрченко, професор, д.т.н., Е.М. Воронова, доцент, Л.С. Михайлова, магктрант, ХНАДУ
Анотаця. В експериментальних до^дженнях tрунтiв придорожтх екологiчних систем вста-новлет концентрацИ нафтового забруднення, а також iдентифiкованi окремi нафтопродук-ти. Показано, що детоксикащя нафтопродуктiв вiдбуваeться монотермтальним шляхом. Техногенне навантаження на до^джент дтянщ не перевищуе можливостi природного сере-довища до самовiдновлення.
Ключов1 слова: нафтопродукти, детоксикащя, грунт придорожнього простору.
Introduction
In discharge gases of internal combustion engines one of the most environmentally harmful constituents are petrochemicals. In diesel and gas engines emissions, petrochemicals are mainly presented by paraffins, naphtenates and
aromatic hydrocarbons. In the atmosphere, petrochemicals in the form of aerosols are spread on the ground biocenoses and accumulated in plants, animals and microorganisms of the top-soil. The penetration of petrochemicals into the topsoil results in active changes in the chemical composition of humic horizon, the deterioration
of the autotrophic assimilation, functional activity inhibition of soil biota and fermentation activity of soil.
Analysis of publications
In nature the detoxification of petroleum hydrocarbons is mainly conditioned by microbal degradation in which three ways of oxidation are distinguished:
- monoterminal oxidation of the methyl group with alcohol, aldehyde and monocarboxylic acid formation;
- monoterminal oxidation with the formation of the appropriate methylketone by means of the secondary alcohol;
- determinal oxidation at which n-alkanet terminal groups are oxidized either simultaneously or consecutively with the formation of fatty dicar-boxylic asid.
The extent of petrochemicals degradation is an objective index of auto purification degree of soils from oil-containing pollutions. The determination of this index allows to define substantially the dimensions of the polluted area caused by the source of petrochemicals discharge (highway) and the range of environmentally safe territory [1, 2].
Purposes and objectives of investigation
The objective of the given work consists in determination of regular occurrence of petrochemicals transformation in the roadside area and the identification compounds formed at their degradation.
Master partition
The object of the research is to determine biological detoxication ways of petrochemicals in the roadside area soil. The concentration of petrochemicals in the soil samples selected at the distance of 0,1m. and 100 m from one of Kharkiv motorways (Pushkinskaya street) was checked by means of gravity measurements according to techniques recommended by normative documents. The qualitative composition of petrochemicals in the tested soil samples were determined by means of thin layer chromatogra-phy on Silufol silica gel plates at distillation of samples in the chromatogram chamber. Chemically pure samples of organic acids dissolved in the chlorinated carbon were used as «testifiers»: monocarboxylic - capronic, heptylic, undecylic, stearin, palmitic, dicarboxylic acids - oxalic,
malic, succinic; tricarboxylic acid - citric; ke-tonic acid - pyruvic acid as well as propionic ether. The extraction of petrochemicals from soil samples was carried out by means of chlorinated carbon. The mixtures for distillation were selected experimentally [3].
According to the carried out researches, the concentration of petrochemicals in the soil at the distance of 0,1m constituted 2600 mg/kg, and at the distance of 100 m from the motorway con-stituled 390 mg/kg. In Ukraine the MPC (maximum permissible concentration) for soil of urban limits is not established there exists only a reference to the roughly allowable concentration of 0,2 g/kg which is tenfold lower and determined in the roadside soil. Thus at the distance of 100 m from the motorway, the concentration of petrochemicals in the soil draws near to the approximately acceptable. Although, according to the data obtained from the analysis of the oil pollution of the roadside area in Voronezhskaya oblast, the background concentration of petrochemicals in this region consists 15 mg/kg of soil. According to the type of soils (black earth) and anthropogenic load on the natural environment, the Kharkiv oblast is close to the Voronezhskaya one. Taking into account such low level of background pollution of soils by petrochemicals one can conclude that at the motorway analysis section in Kharkiv even at the distance of 100 m from the highway the soils are intensively polluted by this anthropogenic product. For compounds identification forming in the soil as a result of petrochemicals detoxication, there was conducted their separation by means of thin - layer chromatography. At the evaluation of chromatographed substances separation degree, there was used the value Rf (table 1) -the relationship of the distance from the center of the spot on the plate to the starting line (x), to the distance (y), covered by the dissolvent (from the starting line to the frontal line).
At the application for hexane and light petroleum distillation recommended for petrochemicals separation Rf - of petrochemicals in soil extractions were equal to 0.
Hence we can draw a conclusion that among researched petrochemicals in soils at the distance of 0,1 and 100 m from the motorway there are no naphthenic and aromatic compounds but there are mainly present polar compounds - oxidation products.
Table 1 Rf-components dependence of oil polluted soil from solvent polarity
Conclusions
On the whole according to the results obtained from conducted researches we can draw the following conclusions:
- concentration of petrochemicals in soils at the distance of 0,1 m from the motorway almost sevenfold exceeds - the same index at the distance of 100 m from the motorway;
- in petrochemicals contained in soil samples, there were identified monocarboxylic saturated acids - heptanoic and undecylic acids that is au evidence of monoterminal way of hydrocarbon oxidation [4];
- soils possess a high auto purification potential from petrochemicals;
Value Rf
Solvent Soil extraction Model petrochemicals
Hexane 0 0
Light petroleum 0 0
Ethyl ether: ethanol 0 0
(2:1)
0-0,45
Ethanol 0,72-0,78 0,83-0,87 0,2-0,93
Ethanol: acetic acid: distilled water 0-0,16 0,53-0,60 0,4-0,7
(10:1:0,4 )
Ethanol: acetic acid : 0,43
distilled water 0,6 -
(10:1,5:0,4) 0,82
For polar petrochemicals separation, there were used polar solvents. By means of the solvent (ethyl alcohol: acetic acid: distilled water) it was possible to separate the petrochemicals components extracted from the soil (picture 1). In soils at the distance of 0,1 m from the motorway their concentration considerably exceeded the concentration in the soil at the distance of 100 m from the motorway. Comparing the values of oil containing soil extractions and «testifiers» there has been established that among compounds that enter the composition of researched petrochemicals there are included monocarboxylic saturated acids - heptanic and undecylic ones that is evidence of monoterminal way of petrochemicals detoxication.
Pic. 1. Chromatogram of petrochemicals extraction from researched soils. 1 - petrochemicals extracted from the soil at the distance of 0,1 m from the motorway; 2 - undecylic acid; 3 - heptanic acid; 4 - oxalic acid; 5 -palmitic acid; 6 - stearic acid
- at the researched motorway section the anthropogenic load does not exceed the possibilities of the natural environment to self-healing.
References
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Рецензент: В. К. Жданюк, професор, д.т.н., ХНАДУ.
Стаття надшшла до редакци 10 грудня 2009 р.
