Search

In this paper, we investigated seasonal variations in concentrations of microplastics (MPs) in surface sediments of a lagoon heavily impacted by human activities, located in northern Tunisia (the Bizerte lagoon, southern Mediterranean Sea). Analyses of 112 sediment samples collected from 28 stations between May 2019 and February 2020 revealed significant seasonal variation in concentrations of total MPs, with the highest levels recorded in August 2019 (109.6 ± 59.8 items kg

This is the first study on the behavior and industrial fluxes of rare earth elements (REE) in the coastal fertilizer plants of Gabes (south-eastern Tunisia), the economic losses related to their wastes, and their environmental and human health hazards. The concentrations of 16 REE were assessed in phosphate rock (PR), phosphogypsum (PG) and phosphogypsum foam (PGF) samples, collected from Gabes plants. REE concentrations ranged from 0.23 (for Sc in PG) to 309.33 mg kg−1 (for Ce in PGF). Ce was the most abundant in the three matrices, with concentrations ranging between 80.40 (in PG) and 309.33 mg kg−1 (in PGF). PGF was the most enriched with REE (1075.32 mg kg−1). The annual flow of REE from the fertilizer factories to the marine environment may reach 1523.67 t. The economic losses related to the discharge of phosphogypsum REE in the Gulf of Gabes (GG) was estimated at ~58 million US$ y−1. The potential hazards of discharged REE on the local environment and human health were also evaluated and discussed. These findings show the need for the development of a new industry exploiting REE from phosphogypsum wastes (short term) and phosphate ores (long term) which should lead to reduce its high environmental and human health footprint and to potential economic gains.

Although several studies previously assessed the contents of trace metals in the sediments of the heavily human-impacted lagoon of Bizerte (northern Tunisia), multi-analytical approaches have not been, so far, used to assess the ecological risks in this water body. This study attempts to provide a comprehensive ecological risk assessment related to the enrichment of the lagoon sediments with seven metals (As, Cd, Cr, Cu, Hg, Pb, and Zn). Significant spatial variations were found in the metal concentrations in sediments, in relation to the degree of coastal human activities and hydrodynamics. This was confirmed with the results of the three pollution indices, Cf, PLI, and Igeo. Concordant results were found with most of the indices used to assess the ecological risks (PERI, PEL, ERL, ERM, M-ERM-Q, TU), indicating higher risks in the southern part of the lagoon. These findings can help to improve the environmental management plan of the socio-economic important lagoon of Bizerte.

International audience; While Tunisia is endemic for hepatitis B virus (HBV), a recent large-scale retrospective study, revealed a very low prevalence (2%) of hepatitis Delta virus (HDV) (Yacoubi et al. in J Clin Virol 72:126-132, 2015). All strains were classified within the genotype 1 (HDV-1) as assessed by nucleotide sequencing of the so-called 'R0' region of the genome described previously. In this study, we aimed to determine the full-length genome sequence of HDV isolates in order to fully characterize the HDV strains spreading in Tunisia. Eleven HDV antibody and RNA positive samples were obtained from the 1615 clinical samples previously studied. The whole genome sequence was obtained for 5 strains by sequencing and realignment of four overlapping regions covering the entire genome, followed by extensive phylogenetic analyses. Tunisian sequences segregated together with Turkish and African sequences and showed 60% GC content. Alignment with an HDV-1 consensus sequence revealed that they exhibited several point mutations in different functional domains of the delta proteins that, according to previous studies, might possibly affect their properties. In conclusion, the first full-length genome sequences of Tunisian HDV isolates are provided, isolates which are closely related to Turkish and Sub-Saharan Africa strains, supporting the hypothesis for the spread of HDV-1-strains from Africa via Tunisia to Turkey, before spread to the rest of the world.

International audience; Background: Tunisia is classified as an area of middle endemic for hepatitis B virus (HBV) infection, however little is known about hepatitis Delta virus (HDV) infection. Objectives: This study aimed to address the prevalence of HDV infection, to identify possible risks factors, and to analyze the genetic diversity of HDV strains that are spreading in Tunisia. Study design: A retrospective large-scale study including 1615 HBsAg positive patients, native of the North East coast of Tunisia, recruited from Gastroenterology departments, was conducted. Demographic, epidemiological, ethnical, clinical and biological data were recorded. HBV and HDV serological analyses and DNA and RNA viral load quantification were performed. Genotyping of HBV and HDV strains was performed using nucleotide sequencing followed by phylogenetic analyses. Results: The study population included 819(50.7%) men and 796(49.3%) women; aged 12-90 years (mean age 41 + 13 years). A very low prevalence of HDV infection, 2% was observed. No risk factor, except a history of hospitalization for surgery was found. All HDV strains belonged to genotype 1, with a wide distribution within the HDV-1 group. They all share the African amino acid marker, a serine at position 202 of the large Delta protein. HBV genotypes were distributed as follows: HBV/D1 (56.8%), HBV/D7 (40.9%), and HBV/A2 (2.3%). Conclusion: Tunisia is a low endemic region for HDV infection, due to an efficient policy of HBV infection control. HDV-1 is the sole genotype found, with a high diversity within this group. Further studies are ongoing in order to better characterize and manage the HBV/HDV-infected patients according to the genetic variability of the viral strains. (C) 2015 Elsevier B.V. All rights reserved.