In March 1994, a report was issued to the Indiana Department of Environmental Management after Jim Allen Maintenance, Inc. found levels of total petroleum hydrocarbons (TPH) exceeding the level appropriate for action (100 parts per million) during an underground storage tank closure report assessment. Creek Run L.L.C Environmental Engineering was contracted by Jay Petroleum to complete an initial site characterization. Through quarterly monitoring of benzene, toluene, ethyl benzene, and methyl tert-butyl ether for 11 years, Creek Run L.L.C determined that biodegradation was occurring. Upon using BIOSCREEN, a contaminant transport modeling software that simulates natural attenuation over time, it was determined that the retardation factor was 1.4, and the biodegradation rate constant was 4.6 per year. This indicates that the contaminant migration is slow in comparison to groundwater flow, and the rate of biodegradation is at an appropriate value to allow natural attenuation to occur on its own.

The Deepwater Horizon (DWH) blowout, in the Gulf of Mexico, heavily contaminated miles of sandy beaches. Previous experience of petroleum contamination has shown that oil residues can persist in the sediments for decades. Biodegradation is the major mechanism of remediation regarding petroleum hydrocarbons. There is an urgent need to evaluate the competent indigenous microbial biomass in contaminated sediments if the risks posed by toxic oil residues, for the coastal ecosystem, are to be minimized. We report a field investigation during December 2010 and January 2011 regarding measurement of microbial activity in a sandy beach at the Bon Secour National Wildlife Refuge in Alabama. One transect of wells for sampling was installed in the beach; starting with multiport one, being most landward and thought to be least exposed to oil residue and ending with multiport four being the most seaward and exposed to the open waters of the Gulf of Mexico. Sediment samples were collected from different depths purposely chosen from above, inside, and below the oil layers for microbial analysis. Dissolved oxygen (DO) measurements were obtained and temperature was recorded while collecting the oxygen measurements. Pore water samples were collected for nutrient content and were monitored using the multiport sampling wells. Moisture content was analyzed from the sediments extracted at various depths at each well. pH and salinity were also analyzed for their contributing affect on the microbial community. Grain size distribution analyses were conducted on samples collected at all wells and at multiple depths to characterize the field study location. Results show that the bacterial biomass, as measured by Adenosine-5-triphosphate (ATP) and numbers of alkane and polycyclic aromatic hydrocarbon (PAH) degraders determined by Most Probable Number (MPN), are consistently higher in the sediment layers where oil had been detected. A very good correlation was observed among the relative abundance of bacteria in the different samples using MPN and ATP measurements. As expected, ATP based estimates of the microbial populations were two orders of magnitude higher than the alkane and PAH numbers determined by MPN, which reflect the non-cultivability of most environmental bacteria. The lower concentrations of PAH degraders than alkane degraders that were observed in this study are consistent with other studies, even though both populations are lower than in studies involving fresh oil trapped in beach or wetland sediments. PAHs (aromatics) are notoriously more resistant to biodegradation than alkanes, therefore allowing a lower number of biomass to grow using them. The overall smaller size of the bacterial numbers could be explained by the naturally occurring low-organic content of beach sand. On the other hand, this may be due to the highly weathered nature of the oil or it could reflect some other limitation. / Civil Engineering

<p>U okviru ovog istraživanja ispitani su: (1) Procesi koji se odvijaju prilikom &nbsp;bioremedijacije zemlji&scaron;ta zagađenog naftom i derivatima nafte, koje je bilo izloženo&nbsp;spontanim abiotičkim i biotičkim procesima degradacije u toku 8 godina, tehnikama&nbsp;biogomila i povr&scaron;inske obrade na poluindustrijskoj (pilot) skali uz optimizaciju&nbsp;tehnolo&scaron;kih parametara sa ciljem povećanja efikasnosti i efektivnosti biodegradacije&nbsp;ugljovodonika; (2) Uticaj starenja, koncentracije, biodsotupnosti i strukture zagađujućih&nbsp;materija na procese biodegradacije i biotransformacije u kontrolisanim laboratorijskim&nbsp;uslovima. Tokom dve godine bioremedijacionog tretmana sadržaj mineralnih ulja opao&nbsp;je za 52% (od 27,8 g/kg do 13,2 g/kg) i 53% (od &nbsp;23,2 g/kg do 10,8 g/kg), dok je sadržaj&nbsp;ukupnih ugljovodonika opao za 43% (od 41,4 g/kg do 23,4 g/kg) i 27% (od 35,3 g/kg do&nbsp;25,8 g/kg) u biogomili i povr&scaron;inskoj obradi respektivno. Efikasnost uklanjanja&nbsp;mineralnih ulja iz zemlji&scaron;ta u dva posmatrana bioremedijaciona tretmana je praktično&nbsp;ista. Međutim, u pogledu sadržaja ukupnih ugljovodonika u biogomili uklonjeno je dva&nbsp;puta vi&scaron;e ukupnih ugljovodonika (gledajući &nbsp;apsolutnu količinu ukupno uklonjenih&nbsp;ugljovodonika). Kinetika biodegradacije mineralnih ulja i ukupnih ugljovodonika u toku&nbsp;tretmana u biogomili u saglasnosti je sa kinetičkim modelima lnC=lnC_0-kt i lnC=lnC_0-kt^0,5. Kinetika biodegradacije mineralnih ulja u toku povr&scaron;inske obrade relativno se&nbsp;dobro može opisati sa dva pomenuta kinetička modela, međutim, znatno bolju&nbsp;korelaciju pokazao je linearni model (C=C_0-kt) primenjen na prvih 92 i poslednjih 200&nbsp;dana eksperimenta. Promena sadržaja ukupnih ugljovodonika u toku povr&scaron;inske obrade&nbsp;zagađenog zemlji&scaron;ta relativno je u dobroj korelaciji samo sa kinetičkim modelom&nbsp;lnC=lnC_0-kt^0,5. Laboratorijska ispitivanja pokazala su da biodegradabilnost i sudbina&nbsp;ugljovodonika u životnoj sredini jako zavise od tipa, starosti i koncentracije zagađujućih&nbsp;materija. Naime, u slučaju zemlji&scaron;ta sveže kontaminiranog dizel uljem, već pri&nbsp;<br />koncentracijama od 20 mg/g uočen toksičan efekat koji je prevaziđen nakon dve nedelje&nbsp;tretmana kao posledica smenjenja prekomerne koncentracije rastvorenih ugljovodonika&nbsp;biotičkim i abiotičkim putem i adaptacije prisutne mikroflore. U slučaju većih&nbsp;koncentracija ovaj efekat je bio jo&scaron; izraženiji. Kod zemlji&scaron;ta kontaminiranog sirovom&nbsp;naftom isti efekat se javlja tek pri koncentraciji od 35 mg/g, kao posledica toga da&nbsp;sirova nafta sadrži manju količinu lako rastvornih ugljovodonika. Za razliku od sveže&nbsp;kontaminiranog zemlji&scaron;ta, na biodegradaciju starog naftnog zagađanja u zemlji&scaron;tu&nbsp;koncentracija nije imala uticaj, u ovakvom zemlji&scaron;tu respiracija je bila na veoma niskom&nbsp;nivou pri svim ispitivanim koncentracijama, ali ne kao posledica toksičnosti, već kao&nbsp;posledica činjenice da se degradabilni deo zagađujućih materija degradirao tokom&nbsp;procesa starenja, tako da su u zemlji&scaron;tu zaostali visokomolekularni &nbsp;te&scaron;ko rastvorni&nbsp;ugljovodonici (smole, asfaltne komponente i dr.) sekvestrovani u zemlji&scaron;tu. Merenja biodostupnosti ugljovodonika (ekstrakcijom sa Tween80) pokazala &nbsp;su da je u zemlji&scaron;tu sveže kontaminiranom dizel uljem i sirovom naftom i starim naftnim zagađenjem oko 95%, 85% i 40% ugljovodonika biodostupno, respektivno. Koncentracija rezidualne frakcije mineralnih ulja i ukupnih ugljovodonika dobijena nakon 48 dana laboratorijskog tretmana u skoro svim probama je veća od predviđenih, &scaron;to je posledica bifaznog pona&scaron;anja ugljovodonika u zemlji&scaron;tu, gde se jedan deo uklanja biodegradacijom, dok drugi deo difunduje u pore zemlji&scaron;ta i kompleksira se sa zemlji&scaron;nom organskom materijom. Količina ugljovodonika iz starog naftnog zagađenja zemlji&scaron;ta koja može da pređe u vodenu fazu je mala reda veličine nekoliko mg/l, međutim, u prirodnim uslovima usled spiranja ugljovodonika sa zemlji&scaron;ta ki&scaron;om, postoji verovatnoća da ovi ugljovodonici dospeju u podzemnu vodu iznad maksimalno dozvoljene koncentracije za vodu za piće (MDK = 10 &mu;g/l) i na taj način degradiraju njen kvalitet. Zbog nemogućnosti daljag uklanjanja zagađenja bioremedijacijom, preostala količina zagađujućih materija koja može dospeti u vodenu fazu bi trebalo da se ukloni nekim drugim remedijacionim tehnikama pre njegovog konačnog bezbednog odlaganja u životnu sredinu.</p> / <p>The aims of this study were to examine: (1) the processes that occur during bioremediation of soil contaminated by oil and oil derivatives, which was exposed to spontaneous abiotic and biotic degradation processes over 8 years, using pilot scale biopiles and landfarming techniques to optimise technological parameters with the aim of increasing the efficiency and effectiveness of hydrocarbons biodegradation. (2) the effect of contaminants weathering, concentration, bioavailability and structure on the biodegradation and biotransformation process under controlled laboratory conditions. Over the two years of bioremediation treatment by biopiles and landfarming, the mineral oil content decreased by 52% (from 27.8 g/kg to 13.2 g/kg) and 53% (from 23.2 g/kg to 10.8 g/kg),&nbsp; and the total hydrocarbon content decreased by 43% (from 41.4 g/kg to 23.4 g/kg) and 27% (from 35.3 g/kg to 25.8 g/kg), respectively. The efficiency of mineral oil removal from soil in these two applied bioremediation treatments was practically the same. However, in terms ofthe absolute amount of total hydrocarbons, twice as many total hydrocarbons were removed in the biopile. The mineral oil and total hydrocarbons biodegradation kinetics in the biopile were in good agreement with&nbsp; the kinetic models lnC = lnC0-kt and lnC = lnC0-kt0.5. The mineral oil biodegradation&nbsp;kinetics during the landfarming treatment is relatively well described with those two kinetic models, however, significantly better correlation is obtained by the linear model (C = C0-kt) applied to the first 92 and last 200 days of the experiment. The change in total hydrocarbons content during the landfarming treatment is in relatively good correlation only with the kinetic model lnC = lnC-kt0.5. The laboratory biodegradation investigation showed that hydrocarbon biodegradability and its fate in the environment strongly depend upon the structure, concentration and weathering of the hydrocarbons. Thus, in the case of diesel contaminated soil, as a consequence of&nbsp; its structure, i.e. the presence in a higher concentration of the soluble and toxic midrange n-alkanes, a toxic effect is detected at a diesel oil concentration of 20 mg/g, although this effect is overcome after two weeks, as a consequence of the decreasing&nbsp; concentration of soluble hydrocarbons in biotic and abiotic processes and microbial adaptation. This effect was more pronounced in the case of the soil withthe highest diesel oil concentration. In crude oil contaminated soil, a toxic effect was observed at a much higher hydrocarbon concentration (35 mg/g) than in the diesel oil contaminated soil, which corresponds to the fact that crude oil contains significantly less soluble hydrocarbon. In contrast to these two freshly contaminated soils, the weathered contaminated soil contaminant concentration did not have an effect on hydrocarbon biodegradation, with biodegradation in this soil actually at a low level at all concentrations, not as a consequence of toxicity, but because the degradable part of the contaminant was already degraded during the weathering process, leaving behind only highly condensed hydrophobic organic contaminants (asphaltenes, resins, etc.) sequestered in the soil. The data obtained for hydrocarbons bioavailability (by Tween80 extraction) showed that the bioavailable hydrocarbon fraction from soils freshly contaminated with diesel oil and crude and weathered oil contamination were approximately 95%, 85% and 40%, respectively. The concentration of residual mineral oil fractions and total hydrocarbons obtained after 48 days of laboratory biodegradability treatment in almost all batches was greater than predicted, as a result of the biphasic behaviour of hydrocarbons in the soil, where some were degraded or lost from the soil and some transformed into the recalcitrant fraction. The amount of hydrocarbons from the weathered soil contamination that can be transferred into the water phase is small, of the order of a few mg/l in magnitude, however, under natural conditions, due to hydrocarbons leaching by rainfall, it is possible that these hydrocarbons infiltrate groundwater above&nbsp; the maximum permissible concentration for drinking water (MAC = 10 &mu;g/l) and thus degrade its quality. As it is not possible to achieve further contamination degradation by bioremediation, the remaining amount of pollutants which can be transferred into the water phase should be removed by some other remediation techniques before its final safe disposal in the environment.</p>

Dans les environnements côtiers, soumis à l’impact des marées noires, les microorganismes jouent un rôle crucial dans le devenir des hydrocarbures pétroliers. Toutefois, de nombreux facteurs influencent les activités microbiennes, notamment par les organismes bioturbateurs qui modifient la pénétration de l’oxygène dans les sédiments. Le travail de la thèse vise à mieux comprendre l’impact d’une pollution pétrolière sur les communautés microbiennes dans des sédiments bio turbés. Il s’agissait de comparer les remaniements structuraux de la communauté microbienne liée à la contamination pétrolière dans des sédiments présentant une faible et une forte activité de bioturbation. Des sédiments marins ont été maintenus en microcosmes durant 9 mois et soumis à quatre conditions : (i) pas de traitement (contrôle), (ii) pétrole, (iii) bioturbation et (iv) pétrole et bioturbation. Les efficacités de dégradation des hydrocarbures pétroliers se sont révélées similaires dans les deux types de sédiments. Par des approches moléculaires, la diversité taxonomique et fonctionnelle des communautés microbiennes totales et métaboliquement actives a été évaluée au cours du temps. Les communautés microbiennes ont subi d’importants remaniements structuraux spécifiques à chaque traitement. Nous suggérons que le fonctionnement global de la communauté est modifié par l’activité bioturbatrice sans pour autant modifier l’activité de dégradation. Ces travaux ont mis en évidence une redondance fonctionnelle de l’activité de biodégradation des hydrocarbures pétroliers des communautés microbiennes. L’isolement de communautés hydrocarbonoclastes a permis de confirmer cette redondance fonctionnelle. / Coastal areas such as mudflats are affected by oil spills. In these environments, microorganisms play a crucial role in the fate of petroleum hydrocarbons. However, many factors influence microbial activities, especially the bioturbating organisms, which altered the oxygen penetration in sediments. The present work attempts to better understand the impact of petroleum contamination on microbial community associated with petroleum contamination in sediments with low and high bioturbation activity. This study is based on microcosm experiments with a device simulating tidal cycles. Marine sediments were maintained for 9 months in microcosms and subjected to four conditions: (i) no treatment (control), (ii) oil, (iii) bioturbation and (iv) oil and bioturbation. Chemical, microbiological and biological analyses were conducted throughout the experiment. The efficiencies of degradation of petroleum hydrocarbons were similar in both sediments. By molecular approaches, we assessed the dynamic of the functional and taxonomic diversity of the total and metabolically active communities during the oil contamination. Microbial communities showed significant structural rearrangements specific for each treatment that resulted in distinct microbial communities in both sediments. Hence, the overall microbial community structure was changed by bioturbating activity without changing the degradation capacity revealing a functional redundancy of the biodegradation capacity of hydrocarbons. This result was further supported by the isolation and characterization of hydro carbonoclastic communities.