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Oil-Pipeline and Oil-Well accidents, and leaky underground storage Oil-tanks can all permanently contaminate massive areas of soil, making them economically useless as well as dangerous to the human health, biological resources, and ecosystems. There are many method of treatment of these contaminated soil by hydrocarbons [1]: stabilization/solidification, bioremediation [2], incineration, soil washing, etc. The present work focuses on the treatment of the contaminated soil by the hydrocarbons with soil washing process using oilfield producedwater (PW). The methodological approach consists of researching the optimum conditions of soil washing based on the optimum of moisture’sparametersbetween PW and contaminated soil such as Liquid/Solid ratio and Liquid/Solid contact time. Another parameter was analysed, it is the successive wash test. The contaminated soil before applying the treatment has 1900 ppm of Total Petroleum Hydrocarbons (TPH). After many washing test, the optimum parameters of test were fixed as follow: The optimum of Liquid/Solid ratio was 100 ml / 100 g and the optimum of Liquid/Solid contact time was 5 minutes.With these optimum conditions and after 4 successive soil washing, we succeeded to reduce the percentage of residual TPH in contaminated soil from 1,9%(1900 ppm) to 0,1% (100 ppm). Keywords:Petroleum industry, Produced Water (PW), Contaminated soil, Total Petroleum Hydrocarbons (TPH), Soil washing.

This work investigated the potential of microbial communities native to an estuarine environment to biodegrade enrofloxacin (ENR) and oxytetracycline (OXY). Sediments collected from two sites in the Douro river estuary (Porto, Portugal) were used as inocula for the biodegradation experiments. Experiments were carried out for one month, during which ENR and OXY (1 mg L−1) were supplemented individually or in mixture to the cultures at 10-day intervals. Acetate (400 mg L−1) was added to the cultures every 3 days to support microbial growth. A series of experimental controls were established in parallel to determine the influence of abiotic breakdown and adsorption in the removal of the antibiotics. Removal of antibiotics was followed by measuring their concentration in the culture medium. Additionally, next-generation sequencing of the 16S rRNA gene amplicon was employed to understand how microbial communities responded to the presence of the antibiotics. At the end of the biodegradation experiments, microbial cultures derived from the two estuarine sediments were able to remove up to 98% of ENR and over 95% of OXY. The mixture of antibiotics did not affect their removal. ENR was removed mainly by biodegradation, while abiotic mechanisms were found to have a higher influence in the removal of OXY. Both antibiotics adsorbed at different extents to the estuarine sediments used as inocula but exhibited a higher affinity to the sediment with finer texture and higher organic matter content. The presence of ENR and OXY in the culture media influenced the dynamics of the microbial communities, resulting in a lower microbial diversity and richness and in the predominance of bacterial species belonging to the phylum Proteobacteria. Therefore, microbial communities native from estuarine environments have potential to respond to the contamination caused by antibiotics and may be considered for the recovering of impacted environments through bioremediation.

The present work describes the occurrence of antibiotic residues in urban wastewaters discharged into southern Sfax wastewater treatment plant (WWTP). Thirteen out of the fifty-six antimicrobial compounds analyzed were detected in the wastewater samples with concentration ranging from 23.30 (for cefalexin) to 690.50 ng/L (for spiramycin) in WWTP influent and from 7.50 (for cefalexin) to 370.04 ng/L (for spiramycin) in WWTP effluent. The highest removal efficiency was observed for trimethoprim (88%), while the lowest one was observed for sulfapyridine (33%).The potential impact of the regenerated waters in the environment and pubic health is also discussed.

Antibiotics are an important group of pharmaceuticals which has been widely used in both human and veterinary medicine. After administration, and depending on the compound chemical properties, 5–90% of the antibiotic dose may be excreted as metabolites or parent compounds. Therefore, large amounts of antibiotics are susceptible to enter in aquatic systems directly via wastewater treatment plants (WWTPs) effluent discharge. However, the application of treated waste water and to agricultural fields to irrigate plants may contaminate agricultural soils, and lead to indirect input of antibiotics into trees.

In this study, the microbial degradation of two antibiotics, enrofloxacin (ENR) and oxytetracycline (OXY), belonging respectively to fluoroquinolones and tetracyclines classes is reported. Biodegradation of the two antibiotics was tested by supplementing culture medium with ENR and OXY individually and in mixture. Two sediments from Douro estuary (Porto, Portugal) were used as inocula. Biodegradation experiments were conducted along a period of 2 months, during which the antibiotics were supplemented to the cultures every 10 days, at the concentration of 1 mgL−1, using acetate as a co-substrate. Complete removal of OXY from the inoculated culture medium was always observed within the 10 days period, while removal of ENR varied between 70% and 90%. The results presented in this study indicate that biodegradation can be an important mechanism for the environmental removal of the tested compounds.

On July 2010, 26 surface sediments of the Gulf of Gabes, Tunisia were sampled at depth ranging from 0.5 to 10 m. These specimens were analyzed to determine Al, Cd, Cr, Cu, Pb, Zn, F, P, and N concentrations and total organic carbon contents. The distribution map shows that the high amounts of pollutants are principally located between the commercial harbor and the fishing harbor of Gabes. Measurements of heavy metal contents were carried out using (absorption atomic spectrometer), where the enrichment factor (EF), the geoaccumulation index (I geo), and the contamination index (CI) are determined. The EF values of all metals were >1.5, corroborate anthropogenic impact on the metal levels in this studied area. However, the I geo and CI values of Cd and Zn elements indicated that sediments collected from sites at the vicinity of the commercial harbor are very contaminated, although for Pb, Cr, and Cu elements these indices indicated that the same sediments are uncontaminated. Statistical analyses (principal component analysis/factor analysis and matrix correlation) show that heavy metals, fluoride, and phosphorus are resulting from the same anthropogenic source.

Oil companies are considered to be a source of chronic pollution with continual discharge of wastewaters into the environment. Thus, the impact of petroleum contamination from French–Tunisian Oil Company on the endorheic basin Sabkhat Boujemal is assessed. This area is a continental depression that has no relation with the sea; instead this basin is just an evaporative system. The results show that aliphatic n-alkanes and polycyclic aromatic hydrocarbons (PAH) concentrations, measured on surficial (0–4 cm) sandy sediments, range from 705 to 4560 mg/kg −1 dry sediment and from 11 to 1124 mg Kg −1 dry sediment, respectively. The spatial distribution of these concentrations shows high levels in the vicinity of the oiled water discharge. The distribution pattern of n-alkanes with no odd or even dominance, high levels of unresolved complex mixture (UCM) (198.1–1500 μg/g−1 dry sediment), associated to the combination of different evaluation indices enhance this assessment. Indeed, levels close to 1 for both car...

A study of chemical and sedimentological parameters integrated with benthic foraminifera investigation was conducted along the northern coast of Gabes Gulf. Thirty-two samples were studied and a total of 68 benthic foraminiferal species were identified. Heavy metals enrichment factors and total hydrocarbon concentrations showed both metal and petrogenic pollution related mainly to phosphogypsum, sewage, and fishing activities. Statistical analysis (bivariate correlation and hierarchical cluster analysis) show a possible control of these pollutants on density, diversity, as well as the taxonomic composition of the benthic foraminiferal assemblages. The extent to which the population was found less dense and less diversified corresponded to the degree to which the sediment was contaminated. In these contaminated sites, an increase in relative abundance of opportunistic species such Ammonia tepida and Haynesina germanica was found. Far from pollution, foraminiferal assemblages are dominated by species characteristic of Mediterranean shallow water (Ammonia beccarii, Ammonia parkinsoniana, Elphidium crispum, Elphidium williamsoni, Elphidium advenum, Peneroplis planatus, Peneroplis pertesus).

Hydrocarbons in surface sediments were studied quantitatively and qualitatively in 18 stations along the coastline of Gabes Gulf in Tunisia. The results show that the total hydrocarbon levels vary along a wide range from 90 to 1,800 ppm. The GC–MS profiles of aliphatic hydrocarbons vary according to the stations and show that the hydrocarbons were derived from various sources. A special feature prevalent in several stations was identified: aliphatic hydrocarbons with distinctive chemical features. This includes a high abundance of even-numbered n-alkanes (n-C14–n-C26, maximizing at n-C18, n-C20 and n-C22) and n-alk-1-enes (n-C14:1–n-C24:1, maximizing at n-C16:1, n-C18:1, n-C20:1 and n-C22:1). This unusual predominance of even-numbered n-alkanes/alkenes is reported for the first time in the Gulf of Gabes and it thus contributes to the information on the rare occurrence of such distributions in the geosphere.