Southern Mediterranean coast pollution: Long-term assessment and evolution of PAH pollutants in Monastir Bay (Tunisia).

In order to evaluate the long-term pollution level(s) of Monastir Bay (Tunisian-Mediterranean coastal area), four sediment cores were collected from the meeting points between the main local streams and the marine environment and investigated. Macroscopic observations and granulometric and chemical compositions showed that this Bay received heterogeneous materials. The distribution of 15 total PAH (priority pollutants) concentrations in different levels of core sediments ranged from 222 to 2992 µg kg-1. Thus, the Bay had been polluted for a long time, and sediments and pollutants had varied anthropogenic sources. After that, local hydrodynamism controlled their distributions. Molecular-weight Polycyclic Aromatic Hydrocarbons (PAHs) and calculated LMW/HMW ratios showed that pollutants were principally a mixture of pyrolytic and petrogenic sources. One part of these pollutants had local origins, and the most important amounts were of distant origins. Monastir Bay was considered a moderate to highly polluted area, and sediments had an ecosystem risk.

Study of organic pollution in superficial sediments of Meliane river catchment area: aliphatic and polycyclic aromatic hydrocarbons.

Organic contaminants can be accumulated in aquatic systems even at trace concentrations with potential threats to the environment and human health. The present study has been performed to evaluate the effects of organochlorines and polyaromatic hydrocarbons on surface sediments of the Meliane river catchment. Their determination provides an essential scientific approach for a better understanding of the expected sources and the processes of bioaccumulation. The concentrations of saturated hydrocarbons in extractable organic matter of the dry sediment were found ranging from 0.58 to 3 83 µg kg-1 and PAHs content ranged from 63 to 131 µg kg-1. These results indicated the adherence of Oued Meliane to the pollution of the Tunis Gulf. The fraction of saturated hydrocarbons extracted from the sediments of Oued Meliane included a majority of organic compounds of biogenic nature with a small oil input. In addition, characterization with the TAR index and the LMW/HMW index confirmed that terrigenous inputs in this fraction are more abundant than aquatic inputs. The characterization of PAHs fraction has shown its pyrolitic origin with a predominance of high molecular weight PAHs.

Effective removal of Cu(II) from aqueous solution over graphene oxide encapsulated carboxymethylcellulose-alginate hydrogel microspheres: towards real wastewater treatment plants.

In the current study, the graphene oxide (GO) encapsulated carboxymethyl cellulose-Alginate (CMC-Alg) hydrogel microspheres were prepared via ionotropic gelation method and characterized using FTIR, TGA, SEM-EDS and surface charge by determining pHpzc. The adsorption of Cu2+ ions from aqueous solution on the graphene oxide embedded CMC-Alg was studied under different experimental conditions, and the results showed that embedded beads had high adsorption capacity compared with pure CMC-Alg beads due to synergetic effect between functional groups GO and CMC-Alg matrix. Adsorption capacities at equilibrium were calculated experimentally as 22.10, 39.96, 41.72 and 64 mg/g for pure CMC-Alg, CMC-Alg/GO 1%, CMC-Alg/GO 3% and CMC-Alg/GO 5%, respectively. The adsorption kinetics were found to follow the pseudo-second-order, and the equilibrium data fitted well with the Langmuir adsorption isotherm. Moreover, the intraparticle diffusion model has been inspected pointing that the adsorption process was found to be sequence of surface adsorption and intraparticle diffusion (IPD). The results suggest that graphene oxide embedded CMC-Alg bead matrix can be efficiently used as an adsorbent for metal ions removal from wastewater.

Quantification of Groundwater - Saline Surface Water Interaction in a Small Coastal Plain in North-East Tunisia using Multivariate Statistical Analysis and Geophysical Method.

Amultivariate statistical analysis used with geophysical investigation enabled the assessment of interaction between saline surface water and groundwater in the coastal plain of Wadi Al Ayn and Daroufa in CapBon peninsula, north-east Tunisia. The application of the Principal Component Analysis (PCA) identified the end members which contribute to groundwater recharge: the wastewater infiltrated from Wadi Al Ayn, the oilfield brine infiltrated to the aquifer through the sandy bed of Wadi Al Ayn, the intruded seawater near Wadi Daroufa in the downstream region and the fresh groundwater flowing from the upstream region. The contribution of wastewater in groundwater recharge varies from 1.4% in the upstream region of Wadi Al Ayn to 77% near its downstream part. The fraction of oilfield brine mixed with groundwater in the alluvial aquifer under Wadi Al Ayn varies from 1% to 13%; whereas the fraction of intruded seawater into the coastal part of the aquifer near Daroufa region varies from 2% to 21%.