Bioaccumulation of polycyclic aromatic hydrocarbons in Solea solea from Bizerte and Ghar El Melh Lagoons (Tunisia) and human health risk assessment.

The present study objective was to assess polycyclic aromatic hydrocarbons in Bizerte and Ghar El Melh Lagoons Solea solea and to assess the potential risk to human health from its consumption. To reach these objectives twenty fish samples from each site were collected and 15 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed in their muscles using high-performance liquid chromatography with a fluorescence detector. Total PAH sole concentrations from Bizerte and Ghar El Melh Lagoons were similar or lower to those recorded in other species from other regions across the world. In the studied fish species, the 2 and 3 ring PAHs are the dominated compounds that enter to the composition of PAHs which indicates that PAHs could be principally derived from a petrogenic origin for the both studied lagoons. The human health risk by sole consumption was evaluated and revealed to exhibit no hazard to the local population health concerning PAH intakes. The findings of this biomonitoring study will help in the implementation of sustainable environmental policies for effective water pollution control and the two investigated lagoons management.

Legacy and Emerging Brominated Flame Retardants in Bizerte Lagoon Murex (Hexaplex Trunculus): Levels and Human Health Risk Assessment.

Occurrence of traditional (PBDEs) and novel (HBB, PBEB, DBDPE) brominated flame retardants, as well as the natural compounds of MeO-PBDEs, were studied in a shellfish species (Hexaplex trunculus) sampled from Bizerte Lagoon. PBDE and MeO-PBDE mean concentrations in murex soft tissues were 187 and 264 ng g-1 lw respectively. The alternative flame retardants were not identified. The sum of PBDE and MeO-PBDE levels recorded in murex from the investigated aquatic ecosystem were comparable or a relatively lower than those reported for other organisms from other regions across the world. The amount of PBDE and MeO-PBDE concentrations from the Bizerte Lagoon recorded in murex were comparable or a relatively lower than those recorded from other areas across the world for other species. There is not a danger to the population health with regard to PBDE intakes associated with the consumption of murex in Bizerte city. We believe that this is the first study of the analysis of these pollutants in marine gastropod mollusks from Tunisian aquatic areas.

Organochlorine pesticides and polychlorinated biphenyls in human adipose tissue from northern Tunisia: Current extent of contamination and contributions of socio-demographic characteristics and dietary habits.

The aims of the present study were to investigate the current exposure levels of persistent organochlorine compounds (OCs) in adipose tissues intraoperatively collected from 40 patients over 20 years undergoing non-cancer-related surgery residing in Northern region of Tunisia (Bizerte), which constitutes an exemplary case, and examined association between levels of contamination and both socio-demographic characteristics and dietary habits. Concentration of hexachlorobenzene (HCB), hexachlorocyclohexane isomers (α-HCH, ß-HCH, γ-HCH and δ-HCH), dichlorodiphenyltrichloroethane isomers (p,p'-DDT and o,p'-DDT) and metabolites (p,p'-DDE, o,p'-DDE, p,p'-DDD and o,p'-DDD) and 12 polychlorinated biphenyls (PCBs) congeners were measured using capillary gas chromatography with electron capture detector. Overall, residue levels of OCs followed the decreasing order of DDTs > PCBs > HCB > HCHs. DDTs levels ranged from 74.49 to 1834.76ngg-1 lipid and contributing to more than 90% to the sum of organochlorine pesticides (OCPs). p,p'-DDE was the most abundant in all samples and the p,p'-DDT/p,p'-DDE ratio (range between 1.85% and 58.45%) suggesting recent and ongoing exposure to banned commercial DDT products. PCB concentrations varied from 29.27 to 322.58ngg-1 lipid and PCB-180, PCB-153 and PCB-138 were the dominant congeners accounting for 70% of total PCBs. We did not find significant correlations between OC exposure levels and sex, parity, habitat areas and smoking habits. In females, the adipose tissue concentrations of DDTs, HCB and PCB-118 were positively correlated with age. There was statistically significant relationship between body mass index (BMI) changes and the adipose tissue levels of HCB and HCHs. No association was found between OCPs levels and dietary factors. However, our study suggests that fish consumption may be an important contributor of PCBs adipose tissue content of PCBs in Tunisian people. The presented work is highly significant, being the first study pointing out the chronic exposure to OCs in Bizerte.

Penta- and 2,4,6-tri-chlorophenol biodegradation during municipal solid waste anaerobic digestion.

In this study isotopic tracing using (13)C labelled pentachlorophenol (PCP) and 2,4,6-trichlorophenol (2,4,6-TCP) is proposed as a tool to distinguish the loss of PCP and 2,4,6-TCP due to biodegradation from other physical processes. This isotopic approach was applied to accurately assess in situ PCP and 2,4,6-TCP degradation under methanogenic conditions in several microcosms made up of household waste. These microcosms were incubated in anaerobic conditions at 35°C (mesophilic) and 55°C (thermophilic) without agitation. The volume of biogas produced (CH4 and CO2), was followed for a period of 130 days. At this stage of stable methanogenesis, (13)C6-PCP and (13)C6-2,4,6-TCP were introduced anaerobically in microcosms and its monitoring at mesophilic and thermophilic conditions was performed in parallel by gas chromatography mass spectrometry (GC-MS) and gas chromatography isotope-ratio mass spectrometry (GC-IRMS). This study proved the almost total dechlorination of bioavailable PCP and 2,4,6-TCP into 4-CP at 35°C. Nevertheless, high rate adsorption in particular materials of the two compounds was observed. Furthermore, Carbon-13 Nuclear Magnetic Resonance ((13)C-NMR) Spectroscopy analysis of (13)C labelled 2,4,6-TCP mesophilic incubations showed the partial mineralization of 4-CP at 35°C to acetate and then to HCO(3-). Consequently, NMR results confirm the biogas isotopic results indicating the mineralization of (13)C labelled 2,4,6-TCP into (13)C (CH4 and CO2). Concerning (13)C labelled PCP mesophilic incubations, the isotopic composition of the biogas still natural until the day 262. In contrast, no dechlorination was observed at 55°C. Thus PCP and 2,4,6-TCP were persistent in thermophilic conditions.

Using an Integrated Approach to Assess the Sediment Quality of an Mediterranean Lagoon, the Bizerte Lagoon (Tunisia).

The present study investigates the quality of surface sediments from the Bizerte lagoon (North Tunisia) using an integrated approach including chemical contaminant analysis, bioassays and sediment quality guidelines (SQGs). Sediment samples were collected at 9 sites and analyzed for eight heavy metals (Hg, Cd, Cr, Cu, Pb, Zn, Ni, Fe and Mn). PAHs, PCBs, OCPs were measured previously in the same sediment samples. Our results indicated that the highest concentrations of metals were found near urban areas due to the municipial and industrial wastewater discharges. Sediment pollution assessment was carried out using geoaccumulation index and enrichment factor, which indicate a widespread pollution by Cd, Pb, Ni and Zn in the studied sediments. For bioassays, aqueous and organic extracts were used to assess toxicity and genotoxicity in sediments by using Microtox(®) and SOS Chromotest, respectively. Toxicity levels were compared to metallic and organic pollutants contents. Our results highlight differences in the pattern of responses between the different assays and show no correlation with all the studied contaminants, emphasizing the influence of other contaminants not analyzed in the present study. Based on SQGs, the results of toxicity assessment indicated that adverse effects caused by Ni and Zn would be expected frequently. Nickel was found to have the highest predicted acute toxicity, followed by Zn, Pb, Cd, Cu and Cr. There was no significant relationship between sediment toxicity calculated from heavy metal concentrations (SQG approach) and those measured with bioassays. These findings support the use of integrated approachs for evaluating the environmental risks of sediments.

Methoxylated polybrominated diphenyl ethers (MeO-PBDE) in human milk from Bizerte, Tunisia.

Methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were determined in 36 human milk samples collected in 2010 from healthy mothers living in Bizerte region from Tunisia. Gas chromatography coupled to mass spectrometry working with negative ion chemical ionization (GC-NCI-MS) was used to identify and quantify residue levels on a lipid basis of organo-brominated compounds. Among the 8 examined MeO-PBDE congeners 6-MeO-BDE-47, 2'-MeO-BDE-68, 4'-MeO-BDE-49 and 5'-MeO-BDE-100 were detected in human milk at different levels and frequencies. This is the first study reporting 5'-MeO-BDE-100 and 4'-MeO-BDE-49 levels in human milk samples. Levels of ∑MeO-PBDEs ranged from 0.23 to 4.70ngg(-)(1) lipid weight (lw) in the samples, with a mean and median value of 1.52 and 1.11ngg(-1)lw respectively. Concentrations of ∑MeO-PBDEs in human milk were negatively correlated with age of primapara mothers (p<0.05) and no age-dependency was observed for multipara mothers. Primapara mothers had higher levels of MeO-PBDEs than multipara mothers however no statistical significance was observed. A weak correlation between ∑PBDEs and ∑MeO-PBDEs was found but not between BDE-47 and its methoxylated analog 6-MeO-BDE-47, suggesting differences in exposure pathways for these contaminants in humans and further supporting the hypothesis that MeO-PBDEs were likely not only originated from PBDE precursors.

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Bizerte Lagoon, Tunisia: levels, sources, and toxicological significance.

To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments from the Bizerte Lagoon (northern Tunisia), 18 surface sediment samples were collected in March 2011 and analyzed for 14 US Environmental Protection Agency priority PAHs by high-performance liquid chromatography. The total concentrations of the 14 PAHs (ΣPAHs) ranged from 16.9 to 394.1 ng g(-1) dry weight (dw) with a mean concentration of 85.5 ng g(-1) dw. Compared with other lagoons, coasts, and bays in the world, the concentrations of PAHs in surface sediments of the Bizerte Lagoon are low to moderate. The PAHs' composition pattern was dominated by the presence of four-ring PAHs (45.8 %) followed by five-ring (26.8 %) and three-ring PAHs (12.7 %). The PAH source analysis suggested that the main origin of PAHs in the sediments of the lagoon was mainly from pyrolytic sources. According to the numerical effect-based sediment quality guidelines of the USA, the levels of PAHs in the Bizerte Lagoon should not exert adverse biological effects. The total benzo[a]pyrene toxicity equivalent values calculated for the samples varied from 3.1 to 53.7 ng g(-1) dw with an average of 10.6 ng g(-1) dw.

LC and LC-MS/MS Studies for the Separation and Identification of Impurities and Degradation Products of Betaxolol.

Betaxolol (Bx) is a selective ß1 receptor blocker used in the treatment of hypertension and glaucoma. The aim of the present work was to demonstrate an approach involving use of liquid chromatography (LC) and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS) for the simultaneous separation, identification and characterization of impurities and of degradation products of betaxolol without their isolation from the reaction mixtures. At optimum condition, and according to ICH guidelines, the limit of detection (LOD) and limit of quantification (LOQ) for Bx are found to be 5.46 and 16.54 µg mL-1, respectively. However, the LOD and LOQ for the major degradation product P6 were 2.15 and 6.53 µg mL-1. Betaxolol was subjected to hydrolytic (acidic and basic) and oxidative, stress conditions according to International Conference on Harmonization (ICH) guideline Q1A (R2), and as results, the drug was found to be labile in acidic, basic and oxidative stress conditions. Based on LC-ESI/MS analysis, the found results revealed that Bx decomposes in acidic, basic and oxidizing environments. All degradation products were identified with the help of their fragmentation pattern and the masses obtained upon the MS analysis.

Organochlorine and organobromine compounds in a benthic fish (Solea solea) from Bizerte Lagoon (northern Tunisia): implications for human exposure.

Information on the occurrence of persistent organic pollutants (POPs) in fish from Tunisia is scarce. In this study, thirty one persistent organic pollutants including organochlorine pesticides (OCPs) (dichlorodihenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB)), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were determined in solea solea muscle, from Bizerte Lagoon (northern Tunisia) and from the Mediterranean Sea (reference area) (northern Mediterranean). In the Bizerte Lagoon, contaminant concentrations generally followed this order: PCBs>DDTs>PBDEs>MeO-PBDEs>HCB>HCHs; while in the Mediterranean Sea, pollutant concentration followed this order: MeO-PBDEs>PCBs>DDTs>PBDEs>HCB>HCHs. Mean levels of organochlorine compounds were 1018 and 380 ng g(-1) lipid weight (lw) in fish from Bizerte Lagoon and the Mediterranean Sea, respectively. Mean concentrations of organobromine compounds were 279 and 301 ng g(-1) lw in sole from Bizerte Lagoon and the Mediterranean Sea, respectively. Organohalogen concentrations in fish from Bizerte Lagoon were similar or slightly lower than those reported for other marine fish species from other locations around the world. PCB, HCH, HCB and PBDE levels were negatively correlated with lipid content, while no such correlation was seen for DDTs. Assessment based on several available guidelines suggested an insignificant human health risk for dietary intake of HCB, lindane and PBDEs associated with consumption of sole. However, the estimated lifetime cancer risk from dietary exposure to DDTs and PCBs is a potential concern.

Time course of organochlorine pesticides and polychlorinated biphenyls in breast-feeding mothers throughout the first 10 months of lactation in Tunisia.

Organochorine (OCs) residues were measured in human breast milk samples from four Tunisian women. Month-mix samples composed of weekly collected breast milk samples were analyzed over the lactation period between 3 days after delivery and 10 months post-partum. The concentrations of dichlorodiphenytrichloroethane and its metabolites (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), dieldrin, and 20 polychlorinated biphenyl congeners (PCBs) were determined by gas chromatography with electron capture detection. The variation of OC residue levels in human milk was investigated for each woman individually. The average p,p'-DDE and p,p'-DDT concentrations declined from 661- and 438-ng g(-1) fat basis at day 3 to 77- and 106-ng g(-1) fat basis after 8 months, respectively. No essential changes in HCB, HCHs, dieldrin, and total PCBs concentrations in human breast milk occurred over the lactation periods investigated; the concentrations remained either relatively constant or show no significant weak decrease.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in adipose tissue of women from Grand Tunis and their association with demographic factors and dietary habits.

Dichlorodiphenyl trichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB) and polychloronated biphenyls (PCBs) were measured in 25 woman adipose tissues collected in 2016 from Grand Tunis, Tunisia. p,p'-DDE, p,p'-DDT, HCB and ß-HCH were the dominant organochlorine pesticides (OCPs) in decreasing order in all samples. The total OCP levels varied from 79 to 343 ng g-1 lipid with a median value of 189 ng g-1 lipid and DDTs contributed approximately 88% to sum OCP. The ratio of p,p'-DDT/p,p'-DDE across all samples is below one, which suggests mainly historic exposure but may indicate some recent exposure to the banned pesticide. The median concentration of PCBs was 109 ng g-1 lipid and ranged between 27 and 204 ng g-1 lipid. PCB-153, PCB-180, PCB-138 and PCB-170 were the most abundant congeners, which contributed about 78% of the total PCBs. Spearman analysis showed that dominant organochlorine compounds (OCs) are highly positive correlated except for PCB-28/31, indicating that women from Tunis are exposed via similar routes. Inhalation exposure could be a possible pathway for the uptake of the less chlorinated congeners. We found positive and statistically significant association with subjects age for HCB (r = 0.517; p = 0.009) and PCBs (r = 0.65; p = 0.001) levels and a weak age-dependent accumulation was found for HCHs (r = 0.375; p = 0.065) and DDTs (r = 0.388; p = 0.056). The concentrations of OC subgroups were not associated with BMI, parity and residence. No association was observed between fish, red/white meat, milk and dairy products consumption and levels of HCB, HCHs and PCBs. DDTs levels were significantly correlated only with milk (p = 0.048) and milk products (p = 0.047) intake.

Organochlorine pesticides and polychlorinated biphenyls in raw bovine milk from various dairy farms in Beja, Tunisia: contamination status, dietary intake, and health risk assessment for the consumers.

We determined organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in raw bovine milk taken directly from the milking equipment for different animals and various farms in Béja region, which is one of the largest milk producing areas in Tunisia. All milk samples were contaminated with one or more pesticides and exhibited measurable concentrations of some PCB congeners. The residue levels are generally marked by the predominance of dichlorodiphenyltrichloroethanes (DDTs) (median: 17.60 ng g-1 fat), followed by hexachlorobenzene (HCB) (median: 14.31 ng g-1 fat), PCBs (median: 4.71 ng g-1 fat), and hexachlorocyclohexanes (HCHs) (median: 0.77 ng g-1 fat). DDT/DDE ratios across the samples vary between 0.09 to 32.24 and exhibit the hypothesis of sustaining illegal use of the banned pesticide. The historical or recent use of OCPs and possible emission sources of PCBs identified near studied farms may lead to increased levels of these contaminants in produced milk. The estimated daily intake (EDI) values were several orders of magnitude below the tolerable daily intake (TDI) fixed by FAO/WHO, though recorded concentration in some samples exceeded the maximum residue limits (MRLs) fixed by the EU, especially for OCPs. According to health risk assessments, consumption of raw milk did not pose an obvious cancer risk or other health problems for local inhabitants.

Hydrocarbons in the atmospheric gas phase of a coastal city in Tunisia: Levels, gas-particle partitioning, and health risk assessment.

Many studies have focused on aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (AHs and PAHs) in different environmental compartments, especially atmospheric particles (aerosols), due to their adverse effects on the environment and human health. However, much less information is currently available on the content of AHs and PAHs in the atmospheric gas phase, which is a major reservoir of volatile and photoreactive compounds. Here, for the first time, we assessed the levels, gas-particle partitioning, human health risks and seasonal variations of AHs and PAHs in the atmospheric gas-phase of Bizerte city (Tunisia, North Africa) over a one-year period (March 2015-January 2016). Σ34PAH concentration in the gas phase over the period ranged from 6.7 to 90.6 ng m-3 and on average was 2.5 times higher in the cold season than in the warm season. Σ28AH concentration in the gas phase over the period ranged from 14.0 to 35.9 ng m-3, with no clear seasonal variations. In the gas phase, hydrocarbons were dominated by low-molecular-weight (LMW) compounds, i.e. 3- and 4-ring for PAHs and < n-C24 for AHs. Gas-phase concentrations of PAHs and AHs accounted for up to 80 % of the total (gas + particle phases) atmospheric concentrations of PAHs and AHs. Further analysis of gas-particle partitioning showed that LMW hydrocarbons preferential accumulated in the gas phase, and that gas-particle partitioning was not in equilibrium but dominated by absorption processes into the aerosol organic matter. Benzo[a]pyrene toxic equivalency quotient (BaP-TEQ) in the gas phase represented on average 37 % of the total atmospheric BaP-TEQ concentration, which was always higher in the cold season. Atmospheric gas is a significant factor in the risks of cancer associated with inhalation of ambient air. The Monte Carlo simulation-based exposure assessment model predicted that outdoor air exposure to PAHs does not pose a cancer risk to infants, but the children, adolescent, and adult populations may face a lower cancer risk during the warm season and a higher risk in the cold season.

First study of bromophenols and hexabromocyclododecanes in seafood from North Africa (case of Bizerte Lagoon, Tunisia): occurrence and human health risk.

In spite of the fact that bromophenols (BPs) and hexabromocyclododecanes (HBCDs) are widely used as flame retardants, no data was available until now on the levels of these two chemicals in North Africa biota. Seafood products might represent one of the main sources of dietary exposure to persistent organic pollutants such as non-dioxin-like polychlorinated biphenyls (ndl-PCBs), brominated flame retardants (BFRs), and polycyclic aromatic hydrocarbons (PAHs). In this study, the concentrations of the ndl-PCBs, PAH4, and BFRs were determined in seafood products from a North African lagoon (Bizerte lagoon). Almost all the compounds were detected (15 out of 18) in the analyzed marine organisms. The accumulation of the contaminants followed the order BFRs > ndl-PCB > PAH4. Mean contaminants concentrations ranged from 0.35 to 28.7 ng g-1 ww for ∑ndl-PCBs; from below limit of quantification to 476 ng g-1 ww for ∑BFRs and from below limit of quantification to 5.30 ng g-1 ww for ∑PAH4. PCB 138, 153, and 180 were the most frequently detected ndl-PCB congeners due to their high resistance to metabolic degradation. 2,4-dibromophenol (2,4-DBP) was the predominant BFR. Chrysene (Chr) was found to be the main contributor to the total PAH4 concentration. Contaminant profiles varied significantly among seafood which may be due to the difference in lipid content, trophic level, feeding behavior, and metabolism. To assess the human health risks, the average daily dose exposure of ndl-PCBs, the dietary daily intake of PAHs and the estimated dietary intake of 3,3-,5,5-tetrabromobisphenol A (TBBPA) and HBCD from seafood were estimated. Findings indicated no adverse effects for human health from any of the analyzed contaminants, except for ndl-PCBs in eel.

Microplastic-sorbed persistent organic pollutants in coastal Mediterranean Sea areas of Tunisia.

Microplastics (MPs) are emerging pollutants of global concern due to their pervasiveness, high sorption ability for persistent organic pollutants (POPs) and direct and indirect toxicity to marine organisms, ecosystems, as well as humans. As one of the major coastal interfaces, beaches are considered among the most affected ecosystems by MPs pollution. The morphological characteristics of MPs (pellets and fragments) collected from four beaches along the Tunisian coast and sorbed POPs, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), were investigated in this study. The results showed that the MPs varied greatly in color, polymer composition and degradation degree. The color varied from colored to transparent and the most prevalent polymer identified using Raman spectroscopy was polyethylene. Scanning electron microscope (SEM) images exhibited various surface degradation features including cavities, cracks, attached diatom remains, etc. The concentrations of Σ12PCBs over all beaches ranged from 14 to 632 ng g-1 and 26 to 112 ng g-1 in the pellets and fragments, respectively, with a notable presence and dominance of highly-chlorinated PCBs such as CB-153 and -138. Among the OCPs, γ-HCH is the only compound detected with concentrations ranging from 0.4 to 9.7 ng g-1 and 0.7 to 4.2 ng g-1 in the pellets and fragments, respectively. Our findings indicate that MPs found on the Tunisian coast may pose a chemical risk to marine organisms as the concentrations of PCBs and γ-HCH in most of the analysed samples exceeded the sediment-quality guidelines (SQG), especially the effects range medium (ERM) and the probable effects level (PEL). As the first report of its kind, the information gathered in this study can serve as the baseline and starting point for future monitoring work for Tunisia and neighbouring countries, as well as for stakeholders and coastal managers in decision-making processes.

Survey of legacy and emerging per- and polyfluorinated alkyl substances in Mediterranean seafood from a North African ecosystem.

Despite the ubiquity of per- and polyfluorinated alkyl substances (PFAS) in all environmental compartments, little is known about the pollution they cause on the African continent, neither on levels, nor effects. Here we examined the occurrence and levels of 21 legacy and emerging PFAS in 9 marine species (3 fish, 2 crustaceans and 4 mollusks) collected from Bizerte lagoon, Northern Tunisia. Furthermore, assessment of potential human health risks through consumption of contaminated seafood was examined. This is the first study assessing PFAS in Mediterranean coastal areas of North Africa. Twelve out of the 21 targeted PFAS were detected, evidencing the occurrence of PFAS in seafood from North Africa, albeit at low levels. The Æ©21PFAS concentrations in all seafood samples ranged from 0.202 ng g-1 dry weight (dw) to 2.89 ng g-1 dw, with a mean value of 1.10 ± 0.89 ng g-1 dw. The profiles of PFAS varied significantly among different species, which might be related to their different trophic level, protein content, feeding behaviour and metabolism. Generally, current exposure to PFAS through seafood consumption indicates that it should not be of concern to the local consumers, at least for those PFAS for which information is available.

Biomarkers responses and polybrominated diphenyl ethers and their methoxylated analogs measured in Sparus aurata from the Lagoon of Bizerte, Tunisia.

This study aimed to the examination of the levels and effects of organobromine compounds (polybrominated diphenyl ethers: PBDEs and methoxylated brominated diphenyl ethers: MeO-PBDEs), in Sparus aurata native to the Lagoon of Bizerte. For that, different biomarkers of exposure (somatic indices, superoxide dismutase, and catalase activities) and effect (malondialdehyde level, histopathologic alterations, and DNA damage) as well as pollutant levels were measured in specimens collected from this impacted ecosystem and the Mediterranean Sea as a reference site. Bizerte Lagoon PBDE fish levels were higher than the Mediterranean Sea, whereas MeO-PBDEs were higher in the reference site. Fish from Bizerte Lagoon presented a higher hepatosomatic index, lower catalase and superoxide dismutase activity, higher level of malondialdehyde, and higher percentage of DNA tail in comparison to fish from the reference area. The histological study of the liver indicated substantial lesions in fish from the polluted site. The results showed strong positive correlations between the concentrations of the PBDE or MeO-PBDE and the MDA and DNA tail % levels and negative correlations for the activities of enzymes of SOD and CAT. Consequently, these findings could suggest a potential link between exposure to these pollutants and the observed biomarker responses in the Bizerte Lagoon seabream. Taken together, these results highlight the importance of biomarker selection and the selected sentinel fish species as useful tools for biomonitoring of aquatic pollution.

Assessment of trace levels of aflatoxins AFB1 and AFB2 in non-dairy beverages by molecularly imprinted polymer based micro solid-phase extraction and liquid chromatography-tandem mass spectrometry.

A selective molecularly imprinted polymer (MIP) adsorbent was synthesised and used in a batch micro-solid phase extraction format for isolating aflatoxins (AFB1, and AFB2) from non-dairy beverages before liquid chromatography-tandem mass spectrometry determination. MIP synthesis (precipitation polymerization in 3 : 1 acetonitrile/toluene as a porogen) was performed with 5,7-dimethoxycoumarin (DMC), methacrylic acid (MAA) and divinylbenzene-80 (DVB) as a dummy template, functional monomer and cross-linker, respectively (1 : 4 : 20 molar ratio). 2,2'-Azobisisobutyronitrile (AIBN) was used as a polymerization initiator. The adsorbent MIP (50 mg) was enclosed in a cone-shaped polypropylene membrane (porous membrane protected molecularly imprinted micro-solid phase extraction), and parameters such as sample pH, mechanical (orbital-horizontal) shaking, the extraction time (loading stage), the composition of the eluting solution, and the desorption time were optimised. The highest extraction yields were obtained by using 5 mL of non-dairy beverages (pH adjusted at 6.0), and mechanical shaking (150 rpm) for 15 min. Elution was performed with 5 mL of an acetonitrile/formic acid (97.5 : 2.5) mixture under ultrasound (325 W, 35 kHz) for 15 min. After eluate evaporation to dryness and re-dissolution in 150 µL of the mobile phase, the pre-concentration factor of the method was 33.3, which yields limits of detection within the 0.085-0.207 µg L-1 range. In addition, the current proposal was shown to be an accurate and precise method through relative standard deviation of intraday and inter-day assays below 18% and analytical recoveries in the range of 91-104%. However, the method was found to suffer from matrix effects.

Aflatoxins screening in non-dairy beverages by Mn-doped ZnS quantum dots - Molecularly imprinted polymer fluorescent probe.

Synthesized molecularly imprinted polymer (MIP) materials have been anchored on the surface of PEG-Mn-doped ZnS quantum dots (QDs) to develop a fluorescence probe for aflatoxins (AFs) recognition/determination in non-dairy beverages. MIP synthesis used 5,7-dimethoxycoumarin (DMC) as a dummy template molecule, and methacrylic acid (MAA) as a functional monomer. Under optimized conditions (1.25 mL of 5 mg L-1 MIP-PEG-ZnS QDs solution, pH 5.0, and 12 min delay time before scanning), the prepared MIP-QDs composite was found to offer high affinity and selectivity for AFs (AFB1, AFB2, AFG1 and AFG2). A fast fluorimetric screening method (total AFs assessment) was therefore feasible. The limits of detection (LOD) and quantification (LOQ) were 0.016 and 0.053 mg L-1, respectively. Analytical recoveries (inter- and intra-day assays) were from 99 ±â€¯4% to 107 ±â€¯5%, with RSD (intra-day assay) lower than 13, and RSD (inter-day) lower than 7%. The optimized method was applied for total AFs assessment in several non-dairy beverage samples.

Occurrence of halogenated flame retardants in sediments and sea urchins (Paracentrotus lividus) from a North African Mediterranean coastal lagoon (Bizerte, Tunisia).

Classic (polybromodiphenyl ethers, PBDEs) and emerging halogenated flame retardants (HFRs) such as hexabromobenzenze (HBB), pentabromoetilbenzene (PBEB), decabromodiphenyl ethane (DBDPE) and halogenated norbornenes (HNs), as well as naturally produced methoxylated-PBDEs (MeO-PBDEs), were analyzed in 12 sediment and 30 urchin (Paracentrotus lividus) samples collected from Bizerte Lagoon in northern Tunisia. Levels of HFRs in the sediments ranged from nd to 51.8 ng/g dry weight (dw), while MeO-PBDEs were not detected. As regards levels in urchins, concentrations of PBDEs, HNs and MeO-PBDEs ranged from 3.67 to 56.9, 4.52 to 116 and nd to 364 ng/g lipid weight (lw), respectively. Thus, levels of naturally occurring compounds were higher than those of an anthropogenic origin. As regards HFRs, the highest contribution comes from HNs with levels ranging between 9.98 and 143 ng/g lw. HN and PBDE concentrations in sea urchin are similar or slightly lower than other reports for other species, while total MeO-PBDE concentrations are higher. The comsumption of sea urchins in Bizerte city is not a threat to public health concerning PBDE intakes.