A chronicle of the changes undergone by a maritime territory, the Bay of Toulon (Var Coast, France), and their consequences on PCB contamination

Abstract

This study evaluated the distribution of polychlorinated biphenyls (PCBs) in 39 surface sediment samples and four cores collected in Toulon Bay, a semiclosed area submitted to various anthropogenic inputs. The concentration of PCBs in the superficial sediment samples ranged from 1.7 to 2530 ng g−1 dry weight. The spatial distribution of these compounds suggested that the high concentrations of these contaminants are located in the small bay and are related to human activities. In the larger bay, the concentrations were in the same order of magnitude than those reported in others locations around the world. Comparison of the levels with target values from the French legislation shows that, except for four polluted sites with critical values (N2: values ≥1 mg kg−1 dry weight) in the smaller bay, PCBs levels throughout the larger and the smaller bay are lower than the accepted values (N1: values <0.5 mg kg−1 dry weight). The PCBs in the sediment cores ranged from 0.8 to 739 ng g−1 dry weight dependent core. Vertical profiles indicated earlier usage of PCBs which coincided with the history of the Toulon Bay. In this study, using alkane, we could follow the PCBs pollution history over about 80 years and estimate a sedimentation rate of about 0.32 cm year in the small Bay of Toulon.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2715-2) contains supplementary material, which is available to authorized users.

Remobilization of polycyclic aromatic hydrocarbons and organic matter in seawater during sediment resuspension experiments from a polluted coastal environment: Insights from Toulon Bay (France)

“…It is located deep inside Toulon Bay and enclosed by a sea wall. Because of this separation, and also the irregular freshwater inputs and the low tide, water circulation in this part of the Bay is limited, leading to low water regeneration and potentially strong accumulation of chemical contaminants such as PAHs in the sediments (Benlahcen et al, 1997;Misson et al, 2016;Wafo et al, 2016). To maintain a navigable water depth, harbor dredging is regularly required in accordance with the current legislation.…”

Historical Trends of Polycyclic Aromatic Hydrocarbons (PAHs) in the Sediments of Toulon Bay (South of France)

“…The vertical distribution of PAH in the cores is presented in Figure 5. Previous studies on sedimentation [8] in Toulon bay estimate rates of 0.32 cm year -1 close to site 15, while [6] found sedimentation rate of 0.27 cm year -1 with 210 Pb activities for the same cores. Ours results provide a valuable basis for studying the chronology of sediment pollution in the smaller bay.…”

“…The granulometry of the surface and cores sediments for this study were described and published in [8]. In the port areas, the total PAH levels range from 0.30 to 34.11 mg.kg -1 (dry weight), with average concentrations of 10.91 mg.kg -1 , in the 0-5 cm layer and from 0.34 to 54.68 mg.kg -1 , with an average concentration of 11.45 mg.kg -1 , in the 5-10 cm layers.…”

Growth, condition and metal concentration in juveniles of two Diplodus species in ports

“…The second site (TLN) was positioned further within the Small Bay (Fig. 1), in one of the most contaminated parts of the Bay of Toulon (Tessier et al, 2011;Wafo et al, 2016) located at about 500 m from the biggest naval port of the Mediterranean (the port of Toulon, which harbors around 30 warships and nuclear submarines) and less than 200 m from a large ferry terminal serving the Corsica island (ca. 1,000 rotations and 1.2 million passengers per year).…”

“…The third sampling site (DLE) was positioned on the seaward side of the main breakwater that separates the Small Bay from the Large Bay ( Fig. 1), in an area that is very little impacted by port pollution (Tessier et al, 2011;Wafo et al, 2016). In the Mediterranean, the seaward sides of peripheral breakwaters have been shown to be colonized by the juvenile of numerous fish species and are generally considered as favorable habitats for juvenile fish growth (Clynick, 2006;Dufour et al, 2009;Guidetti, 2004;Pastor et al, 2013;Pizzolon et al, 2008;Ruitton et al, 2000).…”