Editing Bioaccumulation (section)

== Studies of turtles as model species ==
{{Anchor|Turtles}}
Bioaccumulation in [[turtle]]s occurs when synthetic organic contaminants (i.e., [[PFAS]]), heavy metals, or high levels of trace elements enter a singular organism, potentially affecting their health. Although there are ongoing studies of bioaccumulation in turtles, factors like [[pollution]], [[climate change]], and shifting landscape can affect the amounts of these toxins in the ecosystem.<ref>{{Cite journal |last1=Franke |first1=Christian |last2=Studinger |first2=Gabriele |last3=Berger |first3=Georgia |last4=Böhling |first4=Stella |last5=Bruckmann |first5=Ursula |last6=Cohors-Fresenborg |first6=Dieter |last7=Jöhncke |first7=Ulrich |date=October 1994 |title=The assessment of bioaccumulation |url=https://linkinghub.elsevier.com/retrieve/pii/004565359490281X |journal=Chemosphere |language=en |volume=29 |issue=7 |pages=1501–1514 |doi=10.1016/0045-6535(94)90281-X|bibcode=1994Chmsp..29.1501F |url-access=subscription }}</ref>

The most common elements studied in turtles are [[Mercury (element)|mercury]], [[cadmium]], [[argon]]{{dubious|date=May 2023}}, and [[selenium]]. Heavy metals are released into rivers, streams, lakes, oceans, and other aquatic environments, and the plants that live in these environments will absorb the metals. Since the levels of trace elements are high in aquatic ecosystems, turtles will naturally consume various trace elements throughout various aquatic environments by eating plants and sediments.<ref name=":02">{{Cite journal |last1=Dias de Farias |first1=Daniel Solon |last2=Rossi |first2=Silmara |last3=da Costa Bomfim |first3=Aline |last4=Lima Fragoso |first4=Ana Bernadete |last5=Santos-Neto |first5=Elitieri Batista |last6=José de Lima Silva |first6=Flávio |last7=Lailson-Brito |first7=José |last8=Navoni |first8=Julio Alejandro |last9=Gavilan |first9=Simone Almeida |last10=Souza do Amaral |first10=Viviane |date=2022-07-01 |title=Bioaccumulation of total mercury, copper, cadmium, silver, and selenium in green turtles (Chelonia mydas) stranded along the Potiguar Basin, northeastern Brazil |url=https://www.sciencedirect.com/science/article/pii/S0045653522008244 |journal=Chemosphere |language=en |volume=299 |pages=134331 |doi=10.1016/j.chemosphere.2022.134331 |pmid=35339524 |bibcode=2022Chmsp.29934331D |s2cid=247638704 |issn=0045-6535|url-access=subscription }}</ref> Once these substances enter the bloodstream and muscle tissue, they will increase in concentration and will become toxic to the turtles, perhaps causing metabolic, endocrine system, and reproductive failure.<ref name=":12">{{Cite journal |last1=Frossard |first1=Alexandra |last2=Coppo |first2=Gabriel Carvalho |last3=Lourenço |first3=Amanda Toledo |last4=Heringer |first4=Otávio Arruda |last5=Chippari-Gomes |first5=Adriana Regina |date=2021-05-01 |title=Metal bioaccumulation and its genotoxic effects on eggs and hatchlings of giant Amazon river turtle (Podocnemis expansa) |url=https://doi.org/10.1007/s10646-021-02384-8 |journal=Ecotoxicology |language=en |volume=30 |issue=4 |pages=643–657 |doi=10.1007/s10646-021-02384-8 |pmid=33754232 |bibcode=2021Ecotx..30..643F |s2cid=232315423 |issn=1573-3017|url-access=subscription }}</ref>

Some marine turtles are used as experimental subjects to analyze bioaccumulation because of their shoreline habitats, which facilitate the collection of blood samples and other data.<ref name=":02" /> The turtle species are very diverse and contribute greatly to biodiversity, so many researchers find it valuable to collect data from various species. Freshwater turtles are another model species for investigating bioaccumulation.<ref>{{Cite journal |last1=Beale |first1=David J. |last2=Hillyer |first2=Katie |last3=Nilsson |first3=Sandra |last4=Limpus |first4=Duncan |last5=Bose |first5=Utpal |last6=Broadbent |first6=James A. |last7=Vardy |first7=Suzanne |date=2022-02-01 |title=Bioaccumulation and metabolic response of PFAS mixtures in wild-caught freshwater turtles (Emydura macquarii macquarii) using omics-based ecosurveillance techniques |journal=Science of the Total Environment |language=en |volume=806 |issue=Pt 3 |pages=151264 |doi=10.1016/j.scitotenv.2021.151264 |pmid=34715216 |bibcode=2022ScTEn.80651264B |issn=0048-9697|doi-access=free }}</ref> Due to their relatively limited home-range freshwater turtles can be associated with a particular catchment and its chemical contaminant profile.

=== Developmental effects of turtles ===
Toxic concentrations in turtle eggs may damage the developmental process of the turtle. For example, in the Australian freshwater short-neck turtle (''[[Emydura macquarii|Emydura macquarii macquarii]]''), environmental PFAS concentrations were bioaccumulated by the mother and then offloaded into their eggs that impacted developmental metabolic processes and fat stores.<ref>{{Cite journal |last1=Beale |first1=David J. |last2=Nilsson |first2=Sandra |last3=Bose |first3=Utpal |last4=Bourne |first4=Nicholas |last5=Stockwell |first5=Sally |last6=Broadbent |first6=James A. |last7=Gonzalez-Astudillo |first7=Viviana |last8=Braun |first8=Christoph |last9=Baddiley |first9=Brenda |last10=Limpus |first10=Duncan |last11=Walsh |first11=Tom |last12=Vardy |first12=Suzanne |date=2022-04-15 |title=Bioaccumulation and impact of maternal PFAS offloading on egg biochemistry from wild-caught freshwater turtles (Emydura macquarii macquarii) |journal=Science of the Total Environment |language=en |volume=817 |pages=153019 |doi=10.1016/j.scitotenv.2022.153019 |pmid=35026273 |bibcode=2022ScTEn.81753019B |issn=0048-9697|doi-access=free }}</ref> Furthermore, there is evidence PFAS impacted the gut microbiome in exposed turtles.<ref>{{Cite journal |last1=Beale |first1=David J. |last2=Bissett |first2=Andrew |last3=Nilsson |first3=Sandra |last4=Bose |first4=Utpal |last5=Nelis |first5=Joost Laurus Dinant |last6=Nahar |first6=Akhikun |last7=Smith |first7=Matthew |last8=Gonzalez-Astudillo |first8=Viviana |last9=Braun |first9=Christoph |last10=Baddiley |first10=Brenda |last11=Vardy |first11=Suzanne |date=2022-09-10 |title=Perturbation of the gut microbiome in wild-caught freshwater turtles (Emydura macquarii macquarii) exposed to elevated PFAS levels |journal=Science of the Total Environment |language=en |volume=838 |issue=Pt 3 |pages=156324 |doi=10.1016/j.scitotenv.2022.156324 |pmid=35654195 |bibcode=2022ScTEn.83856324B |s2cid=249213966 |issn=0048-9697|doi-access=free }}</ref>

In terms of toxic levels of heavy metals, it was observed to decrease egg-hatching rates in the Amazon River turtle, ''[[Arrau turtle|Podocnemis expansa]]''.<ref name=":12"/> In this particular turtle egg, the heavy metals reduce the fat in the eggs and change how water is filtered throughout the embryo; this can affect the survival rate of the turtle egg.<ref name=":12" />