The application of bioassays as indicators of petroleum-contaminated soil remediation https://doi.org/10.1016/j.chemosphere.2004.11.049

Abstract: Bioremediation has proven successful in numerous applications to petroleum contaminated soils. However, questions remain as to the efficiency of bioremediation in lowering long-term soil toxicity. In the present study, the bioassays Spirotox, Microtox®, Ostracodtoxkit F™, umu-test with S-9 activation, and plant assays were applied, and compared to evaluate bioremediation processes in heavily petroleum contaminated soils. Six higher plant species (Secale cereale L., Lactuca sativa L., Zea mays L., Lepidium sativum L., Triticum vulgare L., Brassica oleracea L.) were used for bioassay tests based on seed germination and root elongation. The ecotoxicological analyses were made in DMSO/H2O and DCM/DMSO soil extracts. Soils were tested from two biopiles at the Czechowice oil refinery, Poland, that have been subjected to different bioremediation applications. In biopile 1 the active or engineered bioremediation process lasted four years, while biopile 2 was treated passively or non-engineered for eight months. The test species demonstrated varying sensitivity to soils from both biopiles. The effects on test organisms exposed to biopile 2 soils were several times higher compared to those in biopile 1 soils, which correlated with the soil contaminants concentration. Soil hydrocarbon concentrations indeed decreased an average of 81% in biopile 1, whereas in biopile 2 TPH/TPOC concentrations only decreased by 30% after eight months of bioremediation. The bioassays were presented to be sensitive indicators of soil quality and can be used to evaluate the quality of bioremediated soil. The study encourages the need to combine the bioassays with chemical monitoring for evaluation of the bioremediation effectiveness and assessing of the contaminated/remediated soils.

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Soil Dehydrogenases as an Indicator of Contamination of the Environment with Petroleum Products.Water Air Soil Pollut. 2015;226(11):372. Epub 2015 Oct 11

Abstract: The aim of the research was to compare the effects of various petroleum products, biodiesel, diesel oil, fuel oil and unleaded petrol on soil dehydrogenases, and to evaluate biostimulation with compost and urea in the restoration of homeostasis of the soil contaminated with these products. The obtained results allowed for defining the weight of dehydrogenases in monitoring of the environment subjected to pressure from petroleum hydrocarbons. The studies were carried out under laboratory conditions for 180 days, and loamy sand was the soil formation used in the experiment. The petroleum products were used in the following amounts: 0, 2, 4, 8 and 16 g kg-1 DM of soil. Indices of the influence of the petroleum product and the stimulating substance on the activity of dehydrogenases were calculated. It was proved that the petroleum products affect soil dehydrogenases in various ways. Biodiesel, diesel oil and fuel oil stimulate these enzymes, while petrol acts as an inhibitor. Among the substances tested regarding biostimulation of soils contaminated with petroleum products, compost is definitely more useful than urea, and therefore, the former should be used for the remediation of such soils. Stimulation of dehydrogenases by compost, both in contaminated and non-contaminated soils, proves that it may accelerate microbiological degradation of petroleum-derived contaminants.

BTEX is an abbreviation used for four compounds found in petroleum products. These compounds are benzene, toluene, ethylbenzene, and xylene. Benzene, toluene, and xylene is found naturally in such petroleum products as crude oil, diesel and gasoline. Ethylbenzene is gasoline and aviation fuel additive. They too used widely in the manufacturing process. Benzene is used in the production of materials synthetic and consumer products, such as synthetic rubber, plastics, nylon, insecticides and paints. Toluene is used as a solvent for paints, coatings, gums, oils, and resins. ethyl-benzene may be present in consumer products such as paints, inks, plastics, and pesticides. Xilena used as a solvent in printing, rubber, and leather industries. The BTEX term reflects that benzene, toluene, ethylbenzene and xylene are often found together in contaminated locations (TOSC, 2012)

petroleum has hydrocarbon component or Total petroleum Hydrocarbon (TPH) is an organic compound consisting of hydrogen and carbon for example benzene, toluene, ethylbenzene and xylema isomer. Total petroleum Hydrocarbon (TPH) is a measure of the concentration of petroleum hydrocarbon pollutants in the soil or all oil hydrocarbon pollutants in a soil sample often expressed in units of mg of hydrocarbon / kg of soil

The source of the hydrocarbon is important. The volatile BTEX mentioned by some researchers is generally associated with refined petrol/gasoline products. Semi volatile longer chain aliphatic compounds (alkanes) will be associated with refined diesel or heating oil as well as the heavier (higher carbon number) lubricating oils, greases and tars (including crude oil). Most of these should be captured under standard methods for total recoverable hydrocarbons (TRH or TPH) using a solvent extraction and GC analysis. Examination of the GC trace can give you an indication of the the type of HC that may be present (but this gets more difficult the longer the HC has been in the soil). Depending on the nature of the source, you might also want to look for polycyclic aromatic hydrocarbons (PAHs). You need to be careful with soil soil types high in organic matter as the standard TPH analysis will extract natural organic matter / waxes / vegetable oils etc which will be reported as TPH. This interference can be minimised by using clean up techniques before GC analysis. Silca gel clean up is commonly used for example - see link

file:///C:/Users/andrew/Downloads/EnviroMail%2081%20%20%20TRH%20Silica%20and%20Reducing%20Potential%20False%20Positives%20on%20TPH.pdf

you must monitoring the soil contaminated with Naturally Occurring Radioactive Materials (NORM) and Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) consist of materials, usually industrial wastes or by-products enriched with radioactive elements found in the environment, such as uranium, thorium and potassium and any of their decay products, such as radium and radon.

Natural radioactive elements are present in very low concentrations in Earth's crust, and are brought to the surface through human activities such as oil and gas exploration or mining, and through natural processes like leakage of radon gas to the atmosphere or through dissolution in ground water. Another example of TENORM is coal ash produced from coal burning in power plants. If radioactivity is much higher than background level, handling TENORM may cause problems in many industries and transportation