Chen, L.

Gaus, C.

Goot, K.

Grant, S.

Jin, L.

Limpus, C.

Neugebauer, F.

Qi, L.

Villa, C. A.

University of Queensland eSpace

CONTAMINANT EXPOSURE OF MASS STRANDED GREEN SEA TURTLES IN 
AN INDUSTRIAL AREA OFF THE GREAT BARRIER REEF, AUSTRALIA 
 
Gaus C
1
*, Grant S
1
, Jin L
1
, Goot K
1
, Chen L
1
, Villa CA
1
, Qi L
1
, Neugebauer F
2
, Limpus C
3  
 
 
1 
Nat. Research Centre for Environmental Toxicology (Entox), The University of Queensland, 39 Kessels Road, 
Brisbane, QLD 4108, Australia; 
2 
Eurofins GfA Lab Service GmBH, Neulaender Kamp 1, 21079 Hamburg, 
Germany; 
3 
Department of Environment and Resource Management, 41 Boggo Rd, Brisbane QLD 4102 
 
 
Introduction  
Australia’s Great Barrier Reef (GBR) Marine Park supports among the world’s largest remaining congregations 
of endangered green sea turtles
1
. Seagrass beds in nearshore shallow marine areas of the GBR provide important 
foraging grounds to this species, to which they display remarkably high fidelity. Between 1 January 2011 and 28 
February 2012, 260 green turtle deaths were recorded in the Gladstone area compared to 50-51 per year during 
2008-2010
2
. There has also been an increase in the number of other wildlife strandings, as well as outbreaks of 
diseases in fish in this region
3
. Clinical examination of 56 green turtles in this area revealed that the juvenile 
turtle population were in poor health, due most likely to chronic malnutrition
4
. Diseases of the digestive, 
respiratory, and circulatory systems were found and, in most cases, may have developed secondary to chronic 
debilitation.  
 
Extensive flooding occurred in summer of 2010-2011 across much of Queensland, including the Gladstone 
region, resulting in increased freshwater and sediment outflow, and reduced seagrass cover
5
. These climatic 
events are compounded by the Gladstone Harbour region undergoing substantial development of its port 
resources since May 2011
6
. As major port city for Queensland, Gladstone hosts a variety of industries, including 
mining and processing of minerals, liquefied natural gas, chemical industry, as well as agricultural activities 
within the catchment.  
 
In parallel with health assessment of a local green turtle subpopulation
4
, a comprehensive contaminant exposure 
assessment was conducted using predominantly blood of live captured specimens. Of interest were a wide range 
of inorganic and organic contaminants that may have been brought downstream from the catchment with flood 
waters, or have arisen from industrial activities. Here we focus predominantly on reporting the levels of 
persistent halogenated compounds, and present an exposure and risk assessment carried out for dioxins. 
 
Materials and methods  
Blood samples (10-25 mL) were obtained from 40 live green turtles during 8-11 July 2011 from the Boyne River 
Estuary near Gladstone (-23.9 °S, 151.3 °E; central Queensland, Australia). Most animals (n=39) were in their 
juvenile, benthic foraging life stage (average CCL 46; range 39-62 cm); only one specimen was an adult of 
unknown gender (CCL 100 cm). A large proportion of the animals were classified to have poor (35%; n=14) or 
very poor (20%; n=8) body conditions, with the latter showing signs of emaciation
4
. Despite this, blood lipid 
content did not differ significantly between animals with normal (0.14 ±0.038), poor (0.13 ±0.047) or very poor 
(0.16 ±0.064) body conditions, suggesting they consisted mainly of fats not used for storage (e.g. lipoproteins, 
cholesterol). Liver, fat and kidney were collected during necropsy of animals that were euthanized due to poor 
clinical diagnosis for survival (n=3), or found dead (n=6). One gram of each fat, liver and kidney were pooled 
for screening analysis. Whole blood was also pooled (1 mL subsample from all 43 live and euthanized animals) 
for screening analyses. 
 
Analyses:  
Analyses of all organic compounds were performed at Eurofins GfA in Hamburg, Germany in accordance with 
DIN EN ISO/IEC 17025:2005 and are detailed in ref
7
. Analysis for metals and metalloids was undertaken at 
Entox laboratories according to standardised protocols
7
. Non-target-screening using pooled liver samples was 
undertaken to identify any high levels of organic contaminants. Approximately 0.5 g was extracted with n-
hexane using ultrasonication. The raw extract was injected on an Agilent 6890/5973 GC-MS system using a non-
Organohalogen Compounds Vol. 75, 1129-1132 (2013) 1129
polar DB5-type capillary column. EI-mode was used to scan a mass range of m/z 50-600. The 10 most abundant 
peaks were baseline subtracted and manually evaluated against spectra libraries (Wiley 75K; NIST). Target 
screening was carried out using pooled samples to provide initial information on the type and levels of 
contaminants to be expected, and inform further prioritisation for subsequent analysis: Fat was analysed for 
dioxins, and WHO and indicator PCBs; liver for PBDEs, organochlorine pesticides and organotins; and blood 
for PFOS/PFOA. In a third analytical phase, blood from individual live turtles underwent target analyses 
prioritised based on the screening results (i.e. based on contaminant type and expected concentrations, taking 
into account toxic potency). Analyses were carried out and evaluated on a batch-by-batch approach. Where the 
presence of low levels was consistent, the limited volume for blood samples was prioritised for other analytes. 
These latter analyses were carried out for organotins (n=7), WHO-PCBs (n=22), PCDD/Fs (n=22), and 
organochlorine pesticides (n=7); metals and metalloids were also analysed (n=40).  
 
Dioxin and PCB Exposure/risk assessment:  
A probabilistic approach was used to estimate the proportion of the turtles exceeding reported LOAELs for 
various chronic AhR-mediated toxicity endpoints in mammals and birds
8, 9
, as no reptile-specific dose-response 
data is available. Lognormal frequency distributions were fitted to lipid normalised TEQ concentrations in 
juveniles using mammalian and avian TEFs separately, on both a middle and upper bound basis. TEQ was 
transformed to body burdens assuming a uniform distribution for total body lipid content (4 and 12% based on 
ref
10
). As only one adult specimen was obtained, juvenile turtles were assessed separately to the adult. The 
distribution of TEQ body burdens was then predicted using risk modelling software (Crystalball 2000 
Decisioneering Inc.) and compared to body-burden based LOAELs. 
 
Results and discussion 
Non-target screening of pooled liver samples did not reveal particular signals that could be traced to 
environmental contaminants. Using the mass spectra for each of the peaks, the most abundant signals were 
associated with lipids and sterols naturally occurring in biological samples, or the plastic materials used for 
blood sampling (diisobutyl phthalate). Similarly, target screening for pesticides, organotins, PBDEs, dioxins and 
PFOS/PFOA showed their concentrations were mostly near or below the limit of quantification (LOQ) in pooled 
fat, liver and/or blood samples, and similar to background levels reported in other turtles or marine megafauna
11-
13
. 
 
Target analysis of individuals further confirmed low levels of organotins and pesticides, which were mostly 
below LOQ. Middle bound TEQ
df+pcb 
in blood of individual juvenile green turtles from Gladstone averaged 19 
pg g
-1
 lw (range <7.1-39; n=21) on a mammalian TEF (Table 1). Using avian TEFs, the levels were 33 pg g
-1
 lw 
(range 13-62). The TEQ
df+pcb 
levels in Gladstone juvenile specimens were comparable to the lower ranges 
reported for other juvenile green turtles and similarly low trophic marine mammals (dugongs) in Queensland
10
. 
The adult specimen contained considerably higher blood TEQ
df+pcb 
(130 pg g
-1
 lw), comparable to the upper 
ranges reported for higher trophic marine wildlife. The major proportion of this TEQ
df+pcb 
was derived from 
PCDD/Fs (120 pg g
-1
 lw). This may indicate chronic exposure to elevated levels of dioxins, rather than elevated 
recent exposure, but more adult specimens would be required to evaluate this. 
 
Assuming that juvenile turtles included in this study are representative of the Gladstone population, the 
likelihood (% of population) of TEQ body burdens being at or above LOAELs
8, 9
 was determined. At middle 
bound TEQ, up to 6.6% of the juvenile population exceeded LOAELs where biochemical effects may occur in 
mammals (3 ng kg
-1
 bw). On the more conservative upper bound TEQ basis, this percentage increased to 29%. 
On an upper bound TEQ basis, up to 5% of the population also exceeded the LOAEL for developmental toxicity 
effects in avian species (9 ng kg
-1
 bw). While only one adult specimen was obtained, it is noteworthy that the 
estimated body burden (5.0-15 ng kg
-1
 bw (middle bound; mammalian TEFs) and 4.7-14 ng kg
-1
 bw (middle 
bound; avian TEFs)) in this specimen exceeded the LOAEL for immunological and developmental effects in 
both mammals and birds, respectively.  
 
While turtles from other areas in Queensland show similar dioxin (and PCB) concentrations, blood levels of 
several metals and metalloids were clearly higher in many individuals from Gladstone compared to those 
Organohalogen Compounds Vol. 75, 1129-1132 (2013) 1130
reported for most other sea turtles worldwide. These included arsenic (40-20,000 μg/L), cadmium (8.1-110 μg/L), 
cobalt (28-440 μg/L), mercury (<0.22-38 μg/L), nickel (0.67-17 μg/L), selenium (84-8,600 μg/L) and vanadium 
(3.5-38 μg/L). As many of these elements are known to have relatively fast blood clearance half-lives, they are 
likely to reflect recent (weeks to month) exposure. Metal/metalloid concentrations in some of these animals were 
also above or near the concentrations where acute adverse health effects have been observed across different 
vertebrate taxa. Although the sensitivity of sea turtles to these contaminants is mostly unknown, it suggests 
exposure may have been sufficiently high to cause adverse effects. 
 
Acknowledgements 
We thank the Department of Environment and Resource Management, and The University of Queensland 
VetMarti Team for support, particularly with field sampling, necropsy. This study was funded by the Gladstone 
Ports Corporation, Brisbane, Australia and Sea World Research and Rescue Foundation (Ref: SWR/1/2013). 
 
References 
1. Limpus CJ, Cooper PJ, Read MA (1994); Memoires of the Queensland Museum, 35: 139-54 
2. Department of Environment and Resource Management, Queensland Government (2012); Strandings hot 
spots. Queensland, Australia. http://www.derm.qld.gov.au 
3. Department of Employment, Economic Development and Innovation (2011). Fish Health Sampling Reports,  
Gladstone Harbour. Queensland, Australia. http://www.daff.qld.gov.au/28_20943.htm 
4. Eden P, Flint M, Mills, P, Owen H (2011); Health assessment of green sea turtles from Gladstone Harbour: 
July to October 2011. VetVet-MARTI, Gatton, Queensland, Australia 
5. Sankey TL, Hedge SA, McKenzie LJ, McCormack CV, Rasheed MA (2011). Gladstone Permanent Transect 
Seagrass Monitoring. Fisheries Queensland, Australia.  http://www.westernbasinportdevelopment.com.au 
6. Gladstone Ports Corporation (2011); Briefing - Western basin dredging and disposal project environmental 
impacts. Gladstone, Queensland, Australia. http://www.gpcl.com.au 
7. Gaus C, Grant S, Jin NL, Goot K, Chen L, Villa AC, Neugebauer F, Qi L, Limpus C (2012). Haematology, 
blood chemistry and environmental contaminants in green turtle blood from the Gladstone Port. Gladstone 
Ports Corporation Limited, Queensland, Australia. http://www.westernbasinportdevelopment.com.au 
8. World Health Organization (1998); Executive summary: assessment of the health risk of dioxins: re-evaluatin 
of the Tolerable Daily Intake (TDI), European Centre for Environment and Health - International 
Programme on Chemical Safety, Geneva, Switzerland 
9. US EPA (2003); Exposure and Human Health Reassessment of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) 
and Related Compounds - Part II. http://www.epa.gov/ncea/pdfs/dioxin/nas-review/ 
10. Hermanussen SF (2009); Distribution and fate of persistent organic pollutants in nearshore marine turtle 
habitats of Queensland, Australia. PhD Thesis, The University of Queensland, Australia. 
http://espace.library.uq.edu.au/view/UQ:187940 
11. Hermanussen S, Matthews V, Päpke O, Limpus CJ, Gaus C (2008); Marine Pollution Bulletin, 57: 409-18  
12. Swarthout RF, Keller JM, Peden-Adams M, Landry AM, Fair PA, Kucklick JR (2010); Chemosphere 78:  
731-41 
13. Malarvannan G, Takahashi S, Isobe T, Kunisue T, Sudaryanto A, Miyagi T, Nakamura M, Yasumura S, 
Tanabe S (2011); Marine Pollution Bulletin 63: 172-78 
 
 
 
 
 
 
Organohalogen Compounds Vol. 75, 1129-1132 (2013) 1131
Table 1. Descriptive statistics for dioxin and PCB concentrations (pg g
-1
 lw) and middle bound TEQ 
(mammalian TEFs-05) in blood from individual (n=22) green turtles (Chelonia mydas). 
 
Compound Mean Minimum Maximum
25th 
percentile
Median
75th 
percentile
Standard 
error
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs; ppt lw)
TEQ
05
 Σ
PCDD/Fs
†
16 2.7 120 5.8 13 16 5.0
PCDDs
2,3,7,8-TCDD <3.9 <0.69 <12 <1.3 <2.8 <5.5 <0.70
1,2,3,7,8-PeCDD 9.0 <0.89 82 2.7 5.0 8.6 3.5
1,2,3,4,7,8-HxCDD 11 <0.22 90 1.8 3.8 12 4.0
1,2,3,6,7,8-HxCDD 12 2.8 100 4.2 5.9 14 4.3
1,2,3,7,8,9-HxCDD 11 2.7 76 4.1 5.9 13 3.3
1,2,3,4,6,7,8-HpCDD 54 18 180 32 40 65 8.2
OCDD 200 58 (<470) 110 150 260 25
PCDFs
2,3,7,8-TCDF 11 <1.2 43 3.7 6.4 18 2.2
1,2,3,7,8-PeCDF 2.5 <0.44 6.7 1.0 2.1 3.4 0.41
2,3,4,7,8-PeCDF 3.0 <0.34 7.7 1.2 1.8 5.6 0.55
1,2,3,4,7,8-HxCDF 3.0 <0.32 14 0.93 1.7 3.5 0.71
1,2,3,6,7,8-HxCDF 2.7 <0.31 14 0.84 1.7 3.1 0.64
1,2,3,7,8,9-HxCDF 3.6 <0.42 26 1.3 2.6 3.5 1.1
2,3,4,6,7,8-HxCDF 3.2 0.61 19 0.92 1.8 3.2 0.84
1,2,3,4,6,7,8-HpCDF 11 2.5 26 5.1 9.0 16 1.4
1,2,3,4,7,8,9-HpCDF 5.3 <1.0 33 2.1 3.4 5.9 1.4
OCDF 49 19 98 32 43 62 4.8
Polychlorinated biphenyls (PCBs; ppt lw)
TEQ
05
 
Σ
WHO-PCBs
†
8.2 3.7 18 5.1 7.8 9.5 0.77
Non-Ortho
PCB 77 <150 <75 <290 <100 <140 <190 <11
PCB 81 <55 <25 <110 <42 <54 <65 <4.2
PCB 126 <120 <50 <290 <69 <110 <140 <12
PCB 169 <150 <75 <300 <100 <150 <190 <12
Mono-ortho
PCB 105 810 <300 3300 430 640 850 140
PCB 114 <220 <100 <620 <140 <200 <260 <24
PCB 118 3500 <1,500 11000 2100 3000 4200 460
PCB 123 220 <100 440 140 210 280 21
PCB 156 780 <300 2600 410 640 860 120
PCB 157 410 <150 1600 210 330 420 76
PCB 167 620 <250 1800 300 470 590 99
PCB 189 230 <100 520 140 210 280 24
 
 
  
 
Organohalogen Compounds Vol. 75, 1129-1132 (2013) 1132


Contaminant exposure of mass stranded green sea turtles in an industrial area off the Great Barrier Reef, Australia

https://espace.library.uq.edu.au/view/UQ:333897/UQ333897.pdf

Contaminant exposure of mass stranded green sea turtles in an industrial area off the Great Barrier Reef, Australia

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