Spatio-temporal distribution and sources of polycyclic aromatic hydrocarbons in Tunis Lagoon: Concentrations in sediments and Marphysa sanguinea body and excrement.

Despite international recognition as an important coastal wetland, Tunis Lagoon is still subjected to anthropogenic pressures. This article provides valuable data on the spatio-temporal distribution, toxicity, and origins of polycyclic aromatic hydrocarbons (PAHs) in the Tunis Lagoon complex. PAHs' concentrations were measured in Marphysa sanguinea body and excrements, as well as in surface sediments. Total mean PAHs' concentrations reached a maximum of 2398 ng/g dry weight (DW) in sediments, 1007.19 ng/g DW in M. sanguinea, and 2602.05 ng/g DW in excrements. Diagnostic PAHs' ratios were used to determine whether PAHs' origins were pyrogenic or petrogenic. Our data showed a predominance of PAHs with a pyrogenic source. Principal component analysis showed PAHs isolated from polychaetes clearly separated from those measured in sediment and excrement. We believe that sediments are not the main source of bioaccumulation by M. sanguinea. Moreover, the toxicity of PAHs in sediments is moderate to high for benthic organisms.

Bioaccumulation of polycyclic aromatic hydrocarbons (PAH) in Polychaeta Marphysa sanguinea in the anthropogenically impacted Tunis Lagoon: DNA damage and immune biomarkers.

This work assessed the impact of polycyclic aromatic hydrocarbons (PAHs) on the polychaeta Marphysa sanguinea in Tunis Lagoon. Highest PAHs concentrations were accumulated at station E with maximum Σ PAH of 6028,87 ng/g DW. Changes in animal physiology were clearly related to bioaccumulated PAH. In fact, high levels of immune biomarkers (cyclooxygenase [COX] and lysozyme activity with maximum of 44631,10 FU/mn/mg protein and 0,017 lysozyme activity/mn/mg protein, respectively) were recorded at stations B and E. Triacylglycerol (TAG), the energy source, was lowest at the most polluted stations (E and B), while phospholipids (PL) were highest at the control station. Statistical analysis revealed a probable effect of both low and high molecular weight PAHs on variations in energy storage lipids (TAG and sterol and wax esters [SE/WE]) and membrane lipids, particularly PL. Our results encourage the use of M. sanguinea to assess pollution levels in coastal ecosystems.

Spatio-temporal variability of biomarker responses and lipid composition of Marphysa sanguinea, Montagu (1813) in the anthropic impacted lagoon of Tunis.

In this study the Polychaeta Marphysa sanguinea, was tested to investigate the impact of metal pollution on the environmental state of a coastal Mediterranean lagoon, Tunis Lagoon (Tunisia). A multi-biomarker approach comprising glutathione-stransferase, cyclooxygenase, lysozyme activity, and lipid class composition of the Polychaeta was employed on a seasonal basis in the present investigation. The multivariate statistical approach (principal component analysis and Pearson correlation) clearly demonstrated different spatial patterns in biomarker values and lipid class concentrations. The phospholipids were the dominant lipid class in M. sanguinea, with the highest value found at the control station. The impact of pollution was most clearly observed on the main storage lipid class, triacylglycerol, which was lowest in the most impacted sites. Our work suggests that M. sanguinea can be used in warmer Mediterranean costal habitats as a sentinel species of contaminated ecosystems.