Biomonitoring phthalic acid esters in marine turtles: sources of contamination and potential implications

Abstract

Plastic pollution represents a significant planetary threat, with a particularly detrimental impact on marine ecosystems. The pervasiveness of plastics in the marine environment has resulted in ingestion of these materials by a variety of marine organisms. This can occur directly, as observed with sea turtles mistaking plastic bags for jellyfish, or indirectly through the trophic chain. The high prevalence of plastic debris in the gastrointestinal tract of sea turtles has led to the designation of these animals as bioindicators of marine litter [1,2]. One of the most significant adverse effects of plastic ingestion is the potential for chemical contamination of the organism due to the prolonged residence time of the plastic in the gut. This contamination occurs through the uptake of plasticisers, such as phthalic acid esters (PAEs or phthalates) and other toxic compounds accumulated by the plastic and released during digestion. Phthalates have the potential to interfere with the normal processes mediated by hormones, which are essential for growth and development. In addition, the ubiquity of phthalates can be attributed to both anthropogenic contamination and natural origins, as they can be biosynthesised by various organisms, including plants, algae, and bacteria [3]. The objective of this research is to gain a deeper comprehension of the influence of these substances on sea turtles. The concentrations of six phthalates, which were frequently employed as additives, were quantified in diverse tissues and unhatched eggs of sea turtles. The objective was to verify the presence and biodistribution of PAEs in the yolks, albumens, and eggshells, with a view to establishing the origin of contamination. The HPLC/MS analyses revealed high levels of the most lipophilic phthalates in gonadal and liver samples of Caretta caretta and Dermochelis coriacea [1]. Furthermore, although to a lesser extent, elevated levels of contamination were also identified in the eggs of C. caretta [2]. The statistical analysis confirmed significant differences in the biodistribution of each phthalate and their sum between the eggshell, yolk, and albumen. In light of the potential sources of contamination, a hypothesis is proposed that the phthalates present in eggs originate from the mother, specifically from the release of phthalates during the digestive process. This hypothesis, which is supported by other studies, is further reinforced by preliminary tests carried out on eggshells. The distribution of different phthalates among tissues allows for the interpretation of the impact that the metabolic pathways of these substances may have on marine organisms. Acknowledgements Funder: Project funded under the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.4 - Call for tender No. 3138 of 16 December 2021, rectified by Decree n.3175 of 18 December 2021 of Italian Ministry of University and Research funded by the European Union – NextGenerationEU; Award Number: Project code CN_00000033, Concession Decree No. 1034 of 17 June 2022 adopted by the Italian Ministry of University and Research, CUP B73C22000790001, Project title “National Biodiversity Future Center - NBFC”. References [1] D. Savoca, M. Arculeo, S. Barreca, S. Buscemi, S. Caracappa, A. Gentile, M.F. Persichetti, A. Pace (2018). Chasing phthalates in tissues of marine turtles from the Mediterranean Sea. Marine pollution bulletin, 127, 165-169. [2] D. Savoca, M. Arculeo, L. Vecchioni, I. Cambera, G. Visconti, R. Melfi, V. Arizza, A.P. Piccionello, S. Buscemi, A. Pace (2021). Can phthalates move into the eggs of the loggerhead sea turtle Caretta caretta? The case of the nests on the Linosa Island in the Mediterranean Sea. Marine Pollution Bulletin, 168, 112395. [3] Pace, A., Vaglica, A., Maccotta, A., & Savoca, D. (2024). The Origin of Phthalates in Algae: Biosynthesis and Environmental Bioaccumulation. Environments, 11(4), 78.