Phthalic Acid Esters (PAEs) are a group of emerging organic contaminants that have become a serious issue because of their ubiquitous presence on the marine environment worldwide and for the endocrine disrupting effects in animals and humans. However, little is known about their distribution in the Ocean, mainly because of analytical difficulties and the high possibility of ambient sample contamination. Plastic debris in marine environment includes resin pellets, macro- and microplastic fragments, and contains additives such as PAEs that might be released in the aquatic environment in unknown proportion. In our work, we improved an analytical method for the determination of 8 PAEs, at trace levels in marine and fresh waters. In the first part of the thesis, the method was validated for different seawater salinities and wastewater treatment plant outlet. By passing 1 L of sample through glass cartridges packed with 200 mg of Oasis HLB and eluted with 6 mL of ethyl acetate, the recoveries fordimethyl phthalate (DMP), diethyl phthalate (DEP), dipropylphthalate (DPP), di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), benzylbutyl phthalate (BzBP), diethylhexyl phthalate (DEHP) and d-n-octyl-phthalate (DnOP), were 101, 98, 115, 110, 99, 98, 103 and 95 %, respectively, with acceptable blank values (below 0.4-4.0 % of the masses measured in different seawater samples). In a second part, PAE distribution in the Marseille Bay has been evaluated though a one-year monitoring from December 2013 to November 2014. The results showed the occurrence of six PAEs, DMP, DEP, DiBP, DnBP, BzBP and DEHP, with total concentrations ranging from 130 to 1330 ng L-1 (av. 522 ng L-1). DEHP was the most abundant PAE in all of the surface samples and the summer bottom samples, followed by DiBP and DnBP. High concentrations were detected in the bottom water, suggesting that resuspension of PAE-rich sediment, in relation with the accumulation of plastic debris above the seabed plays a significant role in the PAE dynamics in coastal
water. In the last part of this thesis, two common plastic samples as trash plastic bags and insulation layer of electric cables were incubated in natural seawater in laboratory conditions and studied for the release of PAE. Release ws observed for the different PAEs with kinetics varying according to the plastic type. DMP and DEP were preferentially released from the insulation layer of electric cables reaching level of release of 9.5 ± 1.4 and 68.9 ± 10.3 ng g-1, respectively, whereas DiBP and DnBP were released from plastic bags, reaching the highest rate after only one week, at values of 333.4 ± 50.3 and 480.5 ± 72.1 ng g-1, respectively.
Andrea PALUSELLI, Université d’Aix-Marseille, École doctorale Science de l‟environnement, 15-02-2018.