Determination and Maternal Transfer of Heavy Metals (Cd, Cu, Zn, Pb and Hg) in the Hawksbill Sea Turtle (Eretmochelys imbricata) from a Nesting Colony of Qeshm Island, Iran

Abstract

This study was conducted to determine trace metal concentrations (Cd, Cu, Zn, Pb and Hg) in blood and three egg fractions from Eretmochelys imbricata nesting on Qeshm Island in Iran. The results showed detectable levels of all analytes in all fractions. Pb and Hg were detectable in the blood and eggs, reflecting a maternal transfer. With the exception of Cu and Pb, analyzed elements in eggs were concentrated in yolk. Only Zn in blood had a significant correlation with the body size and weight (p < 0.01). It appears that Hawksbill sea turtles can regulate Zn concentrations through homeostatic processes to balance metabolic requirements. The relatively low concentrations of metals in blood support the knowledge that E. imbricata feed mainly on the low trophic levels. All essential and non-essential elements were detectable in blood and in eggs of the hawksbill, reflecting a maternal transfer. Consequently, movement patterns, home ranges of foraging grounds, and availability of food could explain variations in trace element concentrations among female turtles.

Incidence of 49 elements in the blood and scute tissues of nesting hawksbill turtles (Eretmochelys imbricata) in Holbox Island

“…They forage in benthic habitats, over coral reefs, rock outcroppings, seagrass pastures, and mangrove-fringed bays (Bjorndal, 1996). These coastal habitats are often in close proximity to sources of persistent inorganic pollutants, which make their way into the marine environment from industrial, domestic and agricultural sources (Ehsanpour et al, 2014).…”

Evidence and patterns of maternal transfer of metals and trace elements in Western tiger snakes (Notechis scutatus occidentalis) – a pilot study

“…Our data indicate statistical evidence of maternal transfer of manganese and molybdenum between contaminated female Western tiger snakes and their foetuses, and potential maternal transfer of antimony, arsenic, mercury and zinc. Evidence for maternal transfer of arsenic, mercury and zinc exists in other reptiles; however, this is limited to turtles and one snake (Chin et al 2013a;Ehsanpour et al 2014;Van Dyke et al 2014). We could not find any published literature on maternal transfer of antimony, manganese or molybdenum in reptiles.…”

“…Currently, research on maternal transfer of contaminants in reptiles is mostly limited to the oviparous taxa: turtles (Ehsanpour et al 2014) and crocodilians (Rauschenberger et al 2004), whereas squamates (particularly viviparous species) have received little attention. In addition, most of this research has focused on organic contaminants due to their lipophilic properties (Rowe 2008), despite many metals being shown to transfer to offspring during development (Ehsanpour et al 2014). The knowledge of maternal transfer of elements in snakes specifically, is limited to mercury in the viviparous wetland species Nerodia sipedon (Chin et al 2013a;Cusaac et al 2016) and selenium in the oviparous terrestrial species Lamprophis fuliginosus (Hopkins et al 2004).…”

“…Currently, research on maternal transfer of contaminants in reptiles is mostly limited to the oviparous taxa: turtles (Ehsanpour et al . 2014) and crocodilians (Rauschenberger et al . 2004), whereas squamates (particularly viviparous species) have received little attention.…”

“…In addition, most of this research has focused on organic contaminants due to their lipophilic properties (Rowe 2008), despite many metals being shown to transfer to offspring during development (Ehsanpour et al . 2014). The knowledge of maternal transfer of elements in snakes specifically, is limited to mercury in the viviparous wetland species Nerodia sipedon (Chin et al .…”