Environmental quality assessment of the fish farms' impact in the Monastir Bay (eastern of Tunisia, Central Mediterranean): a benthic foraminiferal perspective

Offshore fish farms have been active inside the Monastir Bay, Hammemet Gulf for over 10 years, but their environmental impact is still unknown. This study focuses on the evaluation of the fish farming activity impact in the Monastir Bay as revealed by geochemical and benthic foraminiferal data. Samples were collected around three fish cages at different water depths. Total organic carbon (TOC) and total phosphate (TP) in the sediment show higher values beneath the fish cages and decrease proportionally with distance from the cages. Living foraminiferal assemblages around fish farms are dominated by stress-tolerant species with higher abundances of Ammonia tepida, Rosalina bradyi, Elphidium crispum, and Peneroplis planatus. On the basis of our results, A. tepida and Quinqueloculina seminula are confirmed to be tolerant to elevated nutriment content, while Ammonia parkinsoniana seems to be more sensitive to organic enrichment. We also test the Foram-AMBI that is revealed to be a very promising tool by which evaluating the ecological quality status of marine sediment. The results of the present study confirm the suitability of living benthic foraminifera as bioindicators of organic enrichment induced by aquaculture activities.

Assessment of organic and metallic contamination in the surface sediment of Monastir Bay (Eastern Tunisia): Spatial distribution, potential sources, and ecological risk assessment

To investigate the current environment status in Monastir Bay (Tunisia), surface sediments from 32 stations were assessed for heavy metal and organic matter concentrations, and the results were compared with values of natural metal content, marine sediment quality standards, and other results concerning sediments from other Mediterranean coasts. The study of their spatial distributions refined by complementary approaches, including potential ecological risks determined through the enrichment factor, geo-accumulation index, contamination factor, potential ecological risk index, pollution load index, and principal component analysis, showed a significant impact of multiple anthropogenic sources. Moderate pollution of sediments, particularly by Ni and Cu, was also observed. Moreover, TOC values showed that the northern part of Monastir Bay is characterized by high levels of sediment organic matter because of the presence of fish farm cage. This baseline study can be used to establish background values for future sediment surveys.

Natural and anthropogenic particulate-bound aliphatic and polycyclic aromatic hydrocarbons in surface waters of the Gulf of Gabès (Tunisia, southern Mediterranean Sea)

Particulate-bound aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs) were investigated in the surface waters of the Gulf of Gabès (Tunisia, southern Mediterranean Sea). Samples were collected off the Sfax and Gabès-Ghannouch coasts. Concentrations in total resolved n-alkanes ranged from 0.03 to 3.2 μg L^-1, and concentrations in total parents + alkylated PAHs ranged from bdl to 108.6 ng L^-1. The highest concentrations were recorded in the southern Sfax. AHs were mainly of biogenic origin with odd n-alkane predominance, although an anthropogenic contribution was also detected. The PAH molecular patterns revealed a mixed origin with the presence of low molecular weight and alkylated compounds, characteristic of uncombusted oil-derived products, and the presence of high molecular weight compounds, typical of combustion residues. Rainfall events induced an increase in PAH concentrations by a factor 1.5-23.5. The particle-water partition coefficients (K_oc) suggest that the partitioning of PAHs between the particulate and dissolved phases is driven by hydrophobicity and organic matter composition.

Pulmonary tuberculosis: Diagnostic delay in Tunisia

OBJECTIVE

Early diagnosis and prompt effective therapy are crucial to fight against tuberculosis (TB), particularly in regions with a high prevalence. We aimed to evaluate TB diagnostic delays and identify the associated risk factors.

METHODS

We conducted a survey in various health facilities in Tunisia between March 24th and October 30th, 2014. We included all patients aged ≥ 18 years who presented with pulmonary TB (PTB) and who had been initiated on an anti-TB treatment. We evaluated the time between respiratory symptom onset and treatment initiation. Treatment delays were divided into three categories: delays due to the patient, to the healthcare system, and overall delays.

RESULTS

We included 352 patients in the study (242 men and 110 women). The mean age was 42.2 years±17.7. The median time from symptom onset to treatment initiation was 52.56 days. Patient delays were longer for men, for patients presenting with alcohol dependence, and for patients who already knew they were sick. Healthcare system delays were associated with older age, female patients, patients consulting a private physician, and outpatients.

CONCLUSION

TB symptoms should be better explained to the population and healthcare professionals should be better trained to both reduce such delays and initiate treatment as early as possible.

Soil fluoride spiking effects on olive trees (Olea europaea L. cv. Chemlali)

A pot experiment under open air conditions was carried out to investigate the uptake, accumulation and toxicity effects of fluoride in olive trees (Olea europaea L.) grown in a soil spiked with inorganic sodium fluoride (NaF). Six different levels (0, 20, 40, 60, 80 and 100mM NaF) of soil spiking were applied through NaF to irrigation water. At the end of the experiment, total fluoride content in soil was 20 and 1770mgFkg(-1) soil in control and 100mM NaF treatments, respectively. The comparative distribution of fluoride partitioning among the different olive tree parts showed that the roots accumulated the most fluoride and olive fruits were minimally affected by soil NaF spiking as they had the lowest fluoride content. In fact, total fluoride concentration varied between 12 and 1070µgFg(-1) in roots, between 9 and 570µgFg(-1) in shoots, between 12 and 290µgFg(-1) in leaves, and between 10 and 29µgFg(-1) in fruits, respectively for control and 100mM NaF treatments. Indeed, the fluoride accumulation pattern showed the following distribution: roots>shoots>leaves>fruits. On the other hand, fluoride toxicity symptoms such as leaf necrosis and leaf drop appeared only in highly spiked soils (60, 80 and 100mM NaF).

Alpha heavy chain disease alpha mRNA contain nucleotide sequences of unknown origins

Human alpha heavy chain disease is characterized by the production of abnormally short alpha IgH chains. In previously published cases it has been found that the malignant cells produce abnormal alpha mRNA, lacking VH and CH1 sequences and composed of a leader sequence peptide, sequences of variable length (69 to 84 bp) and of unknown origin, followed by normal CH2 and CH3 sequences. In this study we established the nucleotide sequence of alpha mRNA for six cases of alpha heavy chain disease. We observed that all six alpha mRNA lack the VH and CH1 sequences as do those previously described. They also contain in-frame inserts of unknown origin between the leader peptide and the normal CH2 and CH3 coding sequences. These inserts are of variable length (42 to 105 bp) and they are unrelated. These results suggest the existence of a common mechanism defect leading to deletions/insertions in alpha heavy chain disease rather than a specific interaction between alpha 1 IgH gene with a unique defined molecular species.

[Rearrangement of immunoglobulin genes in alpha heavy chain disease: a criterion of monoclonality]

We have studied the configuration of genes encoding for the heavy and light chains in the tumoral cells of 6 patients affected by alpha heavy chain disease (alpha HCD). The results showed the presence of rearrangement of the alpha heavy chain as well as the kappa light chain genes whereas the lambda genes were in germinal configuration. Thus, these results suggest the presence of a monoclonal compound in the tumoral cells in the alpha HCD.

[Sideropenic dysphagia]

Ten typical cases of sideropenic dysphagia over four years reported and clinical, biological, endoscopic and radiological signs are studied. The authors stress the value of oesophagal opacification for diagnosis. The particularities of our study are the relative high frequency of the disease in Tunisia and the unusual attack in two black patients.