Study of the spatial and historical distribution of sediment inorganic contamination in the Toulon bay (France)

Abstract

This study presents trace elements levels in surface and deep sediments of the Toulon bay (SE France) subjected to anthropogenic inputs (navy base, harbors, etc.). The studied elements (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) are defined as priority contaminants in aquatic systems. Fifty-five points scattered on the entire bay were sampled, allowing the determination of contaminants distribution with a high resolution. Several approaches were used to assess the degree of contamination and the potential toxicity of the Toulon bay sediments: comparison to the French legislation, surface-weighted average metal concentrations, enrichment factors (EF), geoaccumulation indices (Igeo), trace element stock calculation and comparison to sediment quality guidelines. A principal component analysis was performed to reveal common behavior of the studied contaminants. Results demonstrated the very high contamination of the small bay, especially in Hg (EF up to 1500), Cu, Pb and Zn, with export to the large bay further governed by hydrodynamics.

Pb, Cd and Cu distribution and mobility in marine sediments from two ports in Lebanon: Beirut army naval port and Tripoli fishing port

“…These concentrations are comparable to the upper limits detected in sediments of other Mediterranean harbors under the impact of the discharge of untreated wastewater, the presence of solid waste, and harbors activities (boat maintenance, paint particles derived from boat cleaning or from grounded and abandoned vessels, shipping activities, sacrificial anodes, leaching of urban surfaces as roads and nearby parkings, untreated wastewater discharges, etc…) (Adamo et al, 2005;Tessier et al, 2011). These Pb concentrations obtained in Beirut military port sediments are higher than those found in the superficial sediments of ATCL-Yacht port (Jounieh-Lebanon) (17.41 and 45.7 µg.g -1 ) (Tahchy, 2011;unpublished data).…”

“…Cadmium concentrations, similar to lead concentrations, also decreased at points B9 to B12. However, such Cd concentrations that remained high compared to Cd levels detected in the sediments of ATCL port (0.17 and 0.28 µg.g -1 ) (Tahchy, 2011), are probably related to the continuous export of contaminated particles from the inner parts of the port to the external parts, likely induced by sediment resuspension during boats traffic (Tessier et al, 2011).…”

Occurrence, risk assessment, and source apportionment of heavy metals in surface sediments from Khanpur Lake, Pakistan

“…EFs are calculated (Cukrov et al 2011;Iqbal and Shah 2011;Luoma and Rainbow 2008;Tessier et al 2011) by comparing the measured metal levels to the preindustrial levels (Lide 2005). In order to avoid the overestimation or underestimation of the enrichment; geochemical normalization based on the concentration of a conservative element is commonly employed.…”

“…f i is the metal pollution factor, C i is the concentration of metal in the sediments, and C b is the reference value of a given metal in the Earth's crust (Lide 2005). Multiple contamination which is often encountered in natural environments affected by human activities is also calculated in terms of mean-effects range medium-quotient (m-ERM-Q) by the following relationship (de Vallejuelo et al 2010;Long and MacDonald 1998;Tessier et al 2011):…”

Etude hydro-sédimentaire de la Rade de Toulon

“…Les conditions météorologiques ont un impact direct sur la circulation dans la Rade de Toulon, les vents influençant directement son hydrodynamisme (MILLOT et al, 1981 ;DUFRESNE et al, 2014). La granulométrie du fond sédimentaire varie par endroits, mais contient principalement des vases, notamment dans la Petite Rade où les particules fines sont prédominantes dans la couche de surface (figure 2) (TESSIER et al, 2011 ;ARNAUD & CHARMASSON, 2000). La proportion de sable augmente considérablement à proximité des plages artificielles sur la côte nord de la Grande Rade ainsi que dans la partie sud du domaine, où elle atteint jusqu'à 90%.…”