Organochlorine pesticide residues in agricultural draining water in Tunisia.

Organochlorines pesticides (OCPs) are persistent organic pollutants known by their persistence, their ability to bioaccumulate in the food chain and by their toxicity. This work aims to analyze pesticides in draining water samples taken from two different regions from Tunisia. A liquid-liquid extraction method proposed by the International Atomic Energy Agency (IAEA) has been adopted for the extraction of OCPs from draining water. The analysis of these compounds was carried out with a gas chromatography coupled to mass spectrometry. Eight draining water sample was analyzed from the region of Kebili and levels of OCPs ranged between ND and 3.415 ng L-1. Four draining water samples were sampled from the region of Cap Bon and levels of OCPs in draining water varied between 14.955 and 59.305 ng L-1. The concentration of OCPs in draining water didn't exceed the limits standardized by the regulations for drainage water, which makes possible the reuse of this water for agricultural purposes after having undergone a secondary treatment.

Response surface methodology approach for the preparation of a molecularly imprinted polymer for solid-phase extraction of fenoxycarb pesticide in mussels.

The aim of this work was to develop an efficient method for the selective extraction and analysis of fenoxycarb, a carbamate pesticide, in mussel samples using a molecularly imprinted solid-phase extraction device. The optimization of molecularly imprinted polymer synthesis was performed using the experimental design under the response surface methodology approach. A fast rebinding study and Freundlich isotherm adsorption were carried out to calculate binding capacity B, site number n, and affinity constant Kf . The optimum molecularly imprinted polymer was successfully used as sorbent of a solid-phase extraction cartridge for the determination of fenoxycarb in real mussel samples. The range of linearity was 0.3-30 mg/L with a correlation coefficient of 0.991. The limit of detection was 0.247 mg/kg. The recovery of fenoxycarb extracted from mussel samples of Mediterranean sea was 97% (n = 3) with relative standard deviation between 6 and 7% proving the reliability of the developed method.

Determination of Synthetic Musks in Surface Sediment from the Bizerte Lagoon by QuEChERS Extraction Followed by GC-MS.

A new analytical method for the simultaneous determination of eight synthetic musks compounds (SMs) including five polycyclic musks (PCMs) and three nitro musks (NMs) was validated for sediment samples based on a simple QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) sample preparation procedure followed by gas chromatography-mass spectrometry (GC-MS). Good analytical performances were obtained for all the target compounds. For the validation of the method, internal calibration (IC) and internal calibration with QuEChERS (ICQ) were compared. Good linearity was obtained for both calibration methods with determination coefficients (R2) ranging between 0.990 for Musk Xylene (MX) and 0.999 for Tonalide (AHTN) with IC and between 0.991 for Musk Ketone (MK) and 0.999 for Traseolide (ATII) with ICQ. The repeatability ranges were 0.1 %-1.9 % with the IC and 0.1 %-2.6 % with the ICQ. The apparent recoveries obtained for SMs in the standard reference sediment (SRM1944) varied in the range of 70 %-98 % and 75 %-103 % in the sediment from the Bizerte Lagoon (Tunisia). The absolute recoveries ranged between 61 % and 92 % for the SRM1944 and between 61 % and 89 % in the sediment from the Bizerte Lagoon. The limits of detection (LOD) calculated for the two main compounds, Galaxolide (HHCB) and Tonalide (AHTN) were 0.3 and 0.1 ng g-1 respectively. The LODs obtained for ADBI (Celestolide), AHMI (Phantolide), ATII (Traseolide), MM (Muks mosken), MK (Musk Ketone) and MX (Musk Xylene) were 0.08, 0.12, 0.03, 0.34, 0.11, 0.08, 0.10 and 0.15 ng g-1 respectively. The levels of ∑SMs in surface sediments from the Bizerte Lagoon ranged from 1.4 to 4.5 ng g-1, which are 1000 times lower that the predicted no effect concentration (PNEC) for marine organisms.

Distribution of trace metals, aliphatic hydrocarbons and polycyclic aromatic hydrocarbons in sediment cores from the Sicily Channel and the gulf of Tunis (south-western Mediterranean Sea).

Under the framework of the IAEA's Technical Co-operation project RAF7/004, international research cruises were carried out in 2004 to assess the distribution of radionuclides and micropollutants in the south-western Mediterranean Sea. Sediments samples had variable concentrations of total aliphatic hydrocarbons and polycyclic aromatic hydrocarbons ranging from 0.2 to 1.8 microg g(-1) and 26.9 to 364.4 ng g(-1), respectively, in the Sicily Channel and from 0.7 to 2.8 microg g(-1) and 14.7 to 618.1 ng g(-1), respectively, in the open sea of the Gulf of Tunis. Hydrocarbon concentrations changed with depth and were relatively high at 3 cm and 10 cm depths. The use of 'fingerprint' ratios of certain isomeric pairs of polycyclic aromatic hydrocarbons (PAH) and the proportion of 2-3 ring and 4-5 ring PAH concentrations showed that the main origins are characteristic of petroleum sources. The ranges of trace metal concentrations, expressed in microgg(-1), in the Sicily Channel and in the Gulf of Tunis, respectively, were: Hg 0.009-0.2 and 0.02-0.1; Pb 9.9-26.1 and 21.2-32.5; Cd 0.06-0.1 and 0.07-0.33; Fe 23.7-28.1 and 29.9-36.2p; Zn 83-99.5 and 83-104; Mn 309.2-752.5 and 651-814; Cu 17.1-18.5 and 33.5-51.3. Sediment metal abundances were in the order: Mn > Zn > Fe > Cu > Pb > Cd > Hg. The results showed significant differences (p < 0.001) for trace metal and hydrocarbon mean concentrations between the two cores. These concentrations are generally similar to the background levels from the Mediterranean Sea and could be affected by physico-chemical conditions and sedimentation rate as well as biodegradation.

Distribution and partitioning of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons between water, suspended particulate matter, and sediment in harbours of the West coastal of the Gulf of Tunis (Tunisia).

Harbours of La Goulette, Rades and Sidi Bou Said are considered as the principal largest and most important port in the Gulf of Tunis characterised by a direct influence of different activities (sailing, industry and fishing) to the Mediterranean Sea. Due to their social and economic impact, a comprehensive assessment of the spatial distribution and partitioning of 24 polycyclic aromatic hydrocarbons (PAHs) and 18 aliphatic hydrocarbons (AHs) in summer and in winter among overlying water, suspended particulate matter (SPM) and surface sediments is essential. Distribution of hydrophobic organic contaminants in abiotic compartments is important for describing their transfer and fate in aquatic ecosystems and to identify the potential danger due to mobilization of contaminants produced by managing of the same sediments. Total organic carbon (TOC) contents range between 4.3% and 6.5%, with an average value of 5.9% in summer, and between 2.3% and 9.6%, with an average value of 6.1% in winter. The average concentrations of ΣPAH in winter and in summer were respectively 703.1 ng L⁻¹ and 378.4 ng L⁻¹ in seawater, 4599.1 ng g⁻¹ and 3114 ng g⁻¹ in SPM, and 1507.6 ng g⁻¹ dw (dry weight) and 1294.6 ng g⁻¹ dw in surface sediment. For ΣAH the average concentrations in winter and in summer were respectively 701 ng L⁻¹ and 741.7 ng L⁻¹ in seawater, 6743.5 ng g⁻¹ and 6282.9 ng g⁻¹ in SPM, and 4971.3 ng g⁻¹ and 4588.1 ng g⁻¹ in surface sediment. Higher PAH and AH concentrations were observed in SPM than in surface sediment. SPM and water were dominated by PAH with low molecular weight, while for sediment low and high molecular weight PAHs were present. PAH and AH fingerprint ratios, such as pristane to phytane (Pr/Ph), phenanthrene to anthracene (Phe/An) and fluoranthene to pyrene (Fl/Py), suggest that hydrocarbons in all harbours may originate from both pyrolytic and petrogenic sources derived from discharge of untreated sewage and wastewater or from direct input by ship traffic in the area. The results showed significant difference (ANOVA, p < 0.05) for hydrocarbon mean concentrations between all harbours studied and between different matrixes.