Preliminary data on the occurrence of PAH and Anisakis spp. in Moroccan anchovies: Environmental parasitology and human health risk.

This survey focuses on an environmental parasitology study by investigating Polycyclic Aromatic Hydrocarbons (PAH) bioaccumulation and the occurrence of Anisakis spp. on common anchovies collected from Moroccan coasts over 9 months through chemical (PAH) and Biological (Biometrics and parasitic) analysis. Obtained results were statistically analyzed and human health risks from anchovies consumption were assessed. The results obtained highlighted the good biological and chemical status of this fish in all stations of Morocco's coasts. Anisakis spp. was present in only four stations in the Atlantic fringe (maximum prevalence 22.22 %). Results have shown non-significant differences for tissue nature (Muscle, viscera) or spatial variation and were within a low range of concentrations well below the European Commission standards. Results have shown no serious harmful risk for humans from this fish consumption (ILCR and HI), and statistical analysis had shown positive correlations between prevalence and Chr, prevalence and sex-ratio, and prevalence and weight.

Hydrocarbon pollution in Atlantic coast of Mauritania (Levrier Bay Zone): Call for sustainable management.

Levrier Bay is an important fishing area which is under growing anthropogenic pressures seriously threatening this treasure. Among these pressures Polycyclic Aromatic Hydrocarbon are of great environmental concern. Therefore, 16 EPA-PAHs were analyzed using GC-MS in Perna perna species and sediment. Comparison with Dakar (Senegal) and Moroccan coasts shows that PAHs levels are strikingly lower than that of heavily polluted Dakar coast (2474 µg/kg); nevertheless, comparable to Moroccan Casablanca and Tangier coasts (245 and 351 µg/kg, respectively). Ratio analysis indicates the predominance of pyrogenic sources and partial contribution of automotive traffic for the half of 4 sites. Furthermore, statistical analys shows that there are no significative differences, except for Benzo(b)Fluorentene in P. perna tissue and 4 PAHs (Fluorene; Fluorenthene; Pyrene; diBenzo(ah)Anthracene and dBahANT) in sediment for sites samples. Furthermore, bioconcentration indicates that P. perna is an excellent PAHs bioindicator. This points the necessity for immediate introduction of a sound Pollutants monitoring system.

Seasonal variations of phytoplankton assemblages in relation to environmental factors in Mediterranean coastal waters of Morocco, a focus on HABs species.

Studies on phytoplankton and in particular Harmful Algal Blooms (HABs) species in southern Mediterranean waters are scarce. We performed from April 2008 to June 2009 weekly investigations on microphytoplankton community structure and abundance in two contrasted marine ecosystems located in the western Moroccan Mediterranean coast, M'diq Bay and Oued Laou Estuary. Simultaneously, we measured the main physico-chemical parameters. Globally, the two studied areas showed comparable values of the assessed abiotic environmental factors. Temperature and salinity followed seasonal variation with values ranging from 13.5 °C to 21.4 °C and 31 to 36.8, respectively. Average nutrient values in surface water ranged from 0.7 to 45.76 µM for dissolved inorganic nitrogen, 0.02-2.10 µM for PO4 and 0.23-17.46 µM for SiO4 in the study areas. A total of 92 taxa belonging to 8 taxonomic classes were found. The highest number of microphytoplankton abundance reached 1.2 × 106 cells L-1 with diatoms being the most abundant taxa. Factorial Discriminant Analysis (FDA) and Spearman correlation test showed a significant seasonal discrimination of dominant microphytoplankton species. These micro-organisms were associated with different environmental variables, in particular temperature and salinity. Numerous HABs species were encountered regularly along the year. Although Dinophysis species and Prorocentrum lima were present in both sites, no Lipophilic Shellfish Poisoning was detected for the analyzed bivalve mollusks. Domoic acid (DA), produced by toxic species of Pseudo-nitzschia was found with concentrations up to 18 µg DA g-1 in the smooth clam Callista chione. Data showed that the observed persistent and dramatic Paralytic Shellfish Poisoning (PSP) intoxication of mollusks resulted probably of Gymnodinium catenatum proliferations in both studied areas. Contrary to C. chione, the cockle Achanthocardia tuberculatum showed a permanent and extremely high toxicity level during the 15 months survey with up to 7545 µg Equivalent Saxitoxin kg-1 flesh (ten times higher than the sanitary threshold of 800 µg eqSTX Kg-1flesh). The present work highlights for the first time the dynamic of microphytoplankton including HABs species and their associated toxin accumulation in the commercially exploited shellfish in the southern western Mediterranean waters of Morocco. Furthermore, the acquired data will help us to improve the monitoring of HABs species and related toxins in these coastal marine systems.

Occurrence, sources and effects of polycyclic aromatic hydrocarbons in the Tunis lagoon, Tunisia: an integrated approach using multi-level biological responses in Ruditapes decussatus.

Coastal lagoons are critical ecosystems presenting a strategic economic importance, but they are subjected to potential anthropogenic impact. As part of the Tunis lagoon (Tunisia) biomonitoring study, levels, composition pattern and sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediments along with their bioavailability in clam Ruditapes decussatus were investigated in polluted (S2-S4) and reference (S1) sites. In order to investigate the contamination effects at different biological levels in clams, a wide set of biomarkers, including gene expression changes, enzymatic activities disruption and histopathological alterations, was analysed. Biomarkers were integrated in a biomarker index (IBR index) to allow a global assessment of the biological response. Principal component analysis (PCA) was used for chemical and biological data integration to rank the sampling sites according to their global environmental quality. Sediment PAHs levels ranged between 144.5 and 3887.0 ng g-1 dw in the Tunis lagoon sites versus 92.6 ng g-1 dw in the reference site. The high PAH concentrations are due to anthropogenic activities around the lagoon. PAH composition profiles and diagnostic isomer ratios analysis indicated that PAHs were of both pyrolitic and petrogenic origins. Clams sampled from S2 and S3 exhibited the highest PAH contents with 2192.6 ng g-1 dw and 2371.4 ng g-1 dw, respectively. Elevated levels of tissue PAHs were associated to an increase in biotransformation and antioxidant activities, and lipid peroxidation levels along with an overexpression of different genes encoding for general stress response, mitochondrial metabolism and antioxidant defence, in addition to the emergence of severe and diverse histopathological alterations in the clams' digestive glands. IBR index was suitable for sampling sites ranking (S1 = 0 < S4 = 0.4 < S3 = 1.15 < S2 = 1.27) based on the level of PAH-induced stress in clams. PCA approach produced two components (PC1, 83.8% and PC2, 12.2%) that describe 96% of the variance in the data and thus highlighted the importance of integrating contaminants in sediments, their bioaccumulation and a battery of biomarkers of different dimensions for the assessment of global health status of coastal and lagoon areas.