Metal and Metalloid Contamination in Green Sea Turtles (Chelonia mydas) Found Stranded in Southeastern Brazil

Abstract

Sea turtles tend to accumulate high metal levels in their tissues and are considered excellent pollution bioindicators. Studies concerning metal contamination in hatchlings, however, are non-existent for one of the most abundant species in Brazil, green sea turtles, while several other metal assessments in juvenile muscles are still scarce. In this context, this study aimed to analyze the concentrations of 12 elements in kidney and muscle samples from green sea turtles (Chelonia mydas; n = 24) found stranded in Rio de Janeiro, southeastern Brazil. Elemental concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS). The presence of fibropapillomatosis, an increasingly common disease in sea turtles which has been associated to metal contamination, was also evaluated. Most elements (Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg, and Pb) were significantly higher in liver, while Al and As were significantly higher in muscle tissue, indicating bioaccumulation of the latter two elements. No differences between juvenile male and female green turtles were observed for either liver or kidney concerning the investigated elements. Literature comparisons of studies conducted in other areas throughout the Brazilian coast indicate higher concentrations of Cd, Mn, As, Hg, and Zn in kidneys, of probable anthropogenic origin. Several statistically significant inter-elemental correlations were observed between toxic elements, indicating similar sources for these environmental contaminants. Significant correlations between Hg in muscle and kidney and As in the same organs suggest bioaccumulation of both elements in muscle. Three individuals assessed herein exhibited fibropapillomatosis, and further assessments in this regard and potential correlations to the detected metal concentrations are currently being carried out. In addition, evaluations concerning other toxic compounds, as well as deleterious cellular effects, are also underway, since total metal concentrations do not reflect total elemental bioavailability.

Green Sea Turtles (Chelonia mydas) Accumulate Heavy Metals Near a Former Skeet Shooting Range in Kailua, O'ahu, Hawai'i

“…Because only two turtles with FP were included in the present study, no conclusions can be made about the relationship between FP and blood Pb concentration. Some studies have shown a correlation between elevated blood Pb and the occurrence of FP, while others have not (Bruno et al, 2021; da Silva et al, 2016). It thus remains unclear if Pb exposure is linked to FP.…”

Potential effects of heavy metal pollution from a cement factory near Saudi Arabia’s largest green turtle rookery

“…Pollution poses a major threat to the survival of marine turtles (Lutcavage et al, 1997 ), which can accumulate heavy metals through food, water, and sediments (Martínez-López et al, 2021 ; Zaib-Un-Nisa et al, 2021 ). Therefore, turtles are potential bioindicators of heavy metal contamination because they are long-living vertebrates with large home ranges (Bruno et al, 2021 ; Zaib-Un-Nisa et al, 2021 ). Several studies have assessed heavy metal concentrations within stranded sea turtle tissues (Kaska et al, 2004 ; Sakai et al, 1995 ; 2000 ; Storelli & Marcotrigiano, 2000 ), yet fewer studies analyzed trace metal concentrations in the nesting beaches (e.g., Çelik et al, 2006 ).…”