Persistent organic pollutants in the green sea turtle Chelonia mydas: nesting population variation, maternal transfer, and effects on development

Abstract

Persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs), have a wide range of toxic effects on humans and wildlife, and have been reported in a number of endangered sea turtle populations. The present study screened for POPs in a green sea turtle Chelonia mydas population in Peninsular Malaysia and investigated the maternal transfer and effects of POPs on embryonic development. At the Ma'Daerah Turtle Sanctuary, blood, eggs and hatchling blood were collected from 11 nesting female C. mydas. Samples were analysed for 83 PCBs, 23 OCPs and 19 PBDEs using gas chromatography with tandem mass spectrometry. The chemical profiles of eggs from individual turtles were significantly different, indicating variable contaminant uptake during foraging. There was evidence of maternal transfer of POPs to eggs and hatchlings, with significant correlations in sum of PCBs (ΣPCB), sum of PBDEs (ΣPBDE), γ-hexachlorocyclohexane (γ-HCH), trans-chlordane and mirex concentrations between maternal blood and eggs (p < 0.05, R 2 < 0.71), between eggs and hatchling blood (p < 0.05, R 2 < 0.83), and between maternal and hatchling blood (p < 0.05, R 2 < 0.61). In addition, there was congener-specific transfer of PCBs with less lipophilic congeners (e.g. PCB 99) more readily transferred to hatchlings than the more lipophilic congeners (e.g. PCBs 180 + 193). There was also a significant correlation between increasing egg POP concentration and decreasing hatchling mass:length ratio. POPs may therefore have subtle effects on the development of C. mydas eggs, which may compromise offshore dispersal and predator avoidance. KEY WORDS: Chelonia mydas · Persistent organic pollutants · Maternal transfer · Contamination profilesResale or republication not permitted without written consent of the publisher

Are we working towards global research priorities for management and conservation of sea turtles?

“…Toxicity of heavy metals varies with species, developmental stage, environmental conditions, and the anthropogenic source (Godley et al 1999, references in Bucchia et al 2015. Maternal transfer of pollutants to eggs has also recently been described (Guirlet et al 2008, 2010, van de Merwe et al 2010, Ikonomopoulou et al 2011, indicating potential risk to developing embryos. However, very little is known about the toxic effects of chemical contaminants on sea turtles (Finlayson et al 2016).…”

“…Orós et al 2009, Lazar et al 2011, Camacho et al 2013b) in sea turtles continues to grow. However, only 3 studies have further assessed the risks associated with chemical accumulation in sea turtles (Lam et al 2006, van de Merwe et al 2009, Dyc et al 2015. Toxicity of heavy metals varies with species, developmental stage, environmental conditions, and the anthropogenic source (Godley et al 1999, references in Bucchia et al 2015.…”

“…In the first category, studies focus on documenting and describing levels of legal take of sea turtles, either for a specific project or area over time (Humber et al 2011, Valverde et al 2012, Lagueux et al 2014, or globally . These datasets provide necessary information for improved understanding of what kind of directed take exists, and help establish a baseline against which to evaluate future trends.…”

The current state and future directions of marine turtle toxicology research

“…De Andrés et al (2016) also examined hatching success in D. coriacea and found a significant negative correlation with PBDE concentrations. In the third publication, POPs exhibited a significant negative correlation with mass:straight carapace length (SCL) in C. mydas hatchlings, which may reflect a re-allocation of energy from growth to detoxification prior to hatching (van de Merwe et al, 2010b). A smaller mass:SCL ratio may compromise a hatchlings ability for offshore dispersal and predator evasion (van de Merwe et al, 2010b).…”

“…Keller et al (2006) correlated both lymphocyte proliferation (a measure of the ability of lymphocytes to respond to antigens or mitogens) and lysozyme activity (a measure of innate immunity based on an antimicrobial enzyme) with concentrations of organic contaminants in C. caretta. Organic contaminants were also investigated for their effect on the ratio of hatchling mass to straight carapace length (an indicator of body condition) in C. mydas (van de Merwe et al, 2010b). The remaining publications examined the effect of organics on other potential indicators of health, such as septicaemia (bacterial blood infection; n = 1), cachexia (wasting syndrome; n = 1) , and pansteatitis (inflamed body fat; n = 1) (Orós et al, 2013).…”