Lead (Pb) profiles in red coral skeletons as high resolution records of pollution in the Mediterranean Sea - Laboratoire Magmas et Volcans Accéder directement au contenu
Article Dans Une Revue Chemical Geology Année : 2019

Lead (Pb) profiles in red coral skeletons as high resolution records of pollution in the Mediterranean Sea

Résumé

26 Lead concentrations in long-lived Corallium species of known age, from the Mediterranean 27 Sea, Atlantic and Pacific Oceans, were determined by laser ablation, inductively coupled 28 plasma mass spectrometer (LA-ICPMS). Lead concentrations in a 2000-year-old sub-fossil 29 Mediterranean C. rubrum are ca 0.09 ± 0.03 µg/g. For the period 1894-1955, lead 30 concentrations in C. rubrum skeletons from the Mediterranean are stable within the range 0.2-31 0.4 µg/g; concentrations increase to about 1-1.2 µg/g during the period 1960-1978, then 32 decrease progressively to stabilize and reach values in the range 0.2-0.4 µg/g in present-day 33 corals. These variations can be related to the lead gasoline pollution event that (1) started in 34 the early 1950s with the increase of the numbers of cars in the world, and (2) was mitigated 35 by the implementation of new regulations starting in 1975, leading to a return to pre-1950 36 levels in 2000. In the Pacific, lead concentrations in C. japonicum and C. konojoi are lower 37 than in the Mediterranean C. rubrum, with values close to 0.17 ± 0.03 µg/g. The lowest lead 38 concentrations in present-day samples (0.11 µg/g) are found in C. johnsoni and C. niobe from 39 the Azores islands in the Atlantic, and in a Mediterranean C. rubrum from Montecristo Island, 40 one of the least accessible and most protected areas in the Mediterranean Sea. Using lead 41 concentrations in C. rubrum and in the Mediterranean seawaters, a partition coefficient Kd = 42 [Pb/Ca] calcite / [Pb/Ca] seawater of 13 +/-3 is estimated; it allows calculating past and present lead 43 contents in seawater in which corals grew. Application to Corallium species indicates that 44 values endangering human health or threatening the preservation of aquatic ecosystem on 45 long terms were nearly reached or exceeded in Mediterranean seawaters at the maximum of 46 the lead gasoline pollution event in the 1980s. Measurements in C. rubrum from different 47 places in the Mediterranean indicate that present-day seawater concentrations vary between 48 2 40 and 200 pmol/kg. As expected, the lowest concentrations come from protected areas 49 insulated from human activities, while the highest come from places close to lead mining or 50 processing sites. 51

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Dates et versions

hal-02318778 , version 1 (29-01-2020)

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Paternité - Pas d'utilisation commerciale - Pas de modification

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Angèle Ricolleau, Nicole Floquet, Jean-Luc Devidal, Robert Bodnar, Jonathan Perrin, et al.. Lead (Pb) profiles in red coral skeletons as high resolution records of pollution in the Mediterranean Sea. Chemical Geology, 2019, 525, pp.112-124. ⟨10.1016/j.chemgeo.2019.07.005⟩. ⟨hal-02318778⟩
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