Changes in mercury distribution and its body burden in delphinids affected by a morbillivirus infection: Evidences of methylmercury intoxication in Guiana dolphin

Manhães, Bárbara Moura Reis; Santos-Neto, Elitieri; Tovar, Lucas Rodrigues; Guari, Emi B.; Flach, Leonardo; Kasper, Daniele; Galvão, Petrus; Malm, Olaf; Gonçalves, Ramiro; Bisi, Tatiana L.; Azevedo, Alexandre F.; Lailson‐Brito, José

doi:10.1016/j.chemosphere.2020.128286

Cited by 23 publications

(17 citation statements)

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“…The intestinal epithelium is considered a barrier to IHg, more so than MeHg ( Seko et al, 1981 ; Vázquez et al, 2013 ); thus, MeHg demethylation in the gut may reduce the reabsorption of MeHg into the host’s circulation. MeHg demethylation may also occur in the liver due to the formation of Hg-selenium complexes ( Caurant et al, 1996 ; Lailson-Brito et al, 2012 ; Manhães et al, 2021 ); however, in a marine fish (black seabream, Acanthopagrus schlegeli ), the rate of MeHg demethylation in the liver was on average 600 times slower compared to the intestine, suggesting that the intestine was the predominant site for MeHg demethylation in some species ( Wang et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Fecal Methylmercury Correlates With Gut Microbiota Taxa in Pacific Walruses (Odobenus rosmarus divergens)

et al. 2021

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ObjectivesMethylmercury metabolism was investigated in Pacific walruses (Odobenus rosmarus divergens) from St. Lawrence Island, Alaska, United States.MethodsTotal mercury and methylmercury concentrations were measured in fecal samples and paired colon samples (n = 16 walruses). Gut microbiota composition and diversity were determined using 16S rRNA gene sequencing. Associations between fecal and colon mercury and the 24 most prevalent gut microbiota taxa were investigated using linear models.ResultsIn fecal samples, the median values for total mercury, methylmercury, and %methylmercury (of total mercury) were 200 ng/g, 4.7 ng/g, and 2.5%, respectively, while in colon samples, the median values for the same parameters were 28 ng/g, 7.8 ng/g, and 26%, respectively. In fecal samples, methylmercury was negatively correlated with one Bacteroides genus, while members of the Oscillospirales order were positively correlated with both methylmercury and %methylmercury (of total mercury). In colon samples, %methylmercury (of total mercury) was negatively correlated with members of two genera, Romboutsia and Paeniclostridium.ConclusionsMedian %methylmercury (of total mercury) was 10 times higher in the colon compared to the fecal samples, suggesting that methylmercury was able to pass through the colon into systemic circulation. Fecal total mercury and/or methylmercury concentrations in walruses were comparable to some human studies despite differences in seafood consumption rates, suggesting that walruses excreted less mercury. There are no members (at this time) of the Oscillospirales order which are known to contain the genes to methylate mercury, suggesting the source of methylmercury in the gut was from diet and not in vivo methylation.

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Section: Introductionmentioning

confidence: 99%

Fecal Methylmercury Correlates With Gut Microbiota Taxa in Pacific Walruses (Odobenus rosmarus divergens)

et al. 2021

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“…Likewise, recently, Guiana dolphins from Sepetiba Bay and Ilha Grande bay in Rio de Janeiro state suffered from a relevant mortality rate of 20.9−35.7 and 4.8−11.1%, respectively, during an unusual mortality event triggered by a morbillivirus outbreak. 79,80 The elevated concentrations of PCBs found in Guiana dolphins from the SE region (MAQUA, unpublished data) may also have had an important effect on the immunological response toward the morbillivirus infection.…”

Section: Resultsmentioning

confidence: 99%

Long-Term Consequences of High Polychlorinated Biphenyl Exposure: Projected Decline of Delphinid Populations in a Hotspot for Chemical Pollution

Oliveira-Ferreira

Carvalho

Santos-Neto

et al. 2021

Environ. Sci. Technol.

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Rough-toothed dolphins, Steno bredanensis, are closely associated with coastal waters in the Southwestern Atlantic Ocean, increasing the exposure to multiple stressors, such as chemical pollution. Persistent organic pollutants (POPs) are known to affect the health of cetacean species. To comprehend the potential impacts of POPs on populations’ viability, it is necessary to distinguish populations and predict their risk of long-term exposure. Blubbers of rough-toothed dolphins (n = 28) collected along the southeastern (SE) and southern (S) Brazilian coast were screened for polychlorinated biphenyls (PCBs) and pesticides in a gas chromatograph coupled to a mass spectrometer. Based on the contamination profile, a discriminant function analysis separated the rough-toothed dolphins into three ecological populations: two coastal and one offshore. POP concentrations were the highest reported for the species worldwide and highest among the delphinids in Brazilian waters, reaching 647.9 μg g–1 lw for PCBs. The SE population presented 212.9 ± 163.0, S population presented 101.0 ± 96.7, and OCS/S population presented 183.3 ± 85.3 μg g–1 lw (mean ± SD) of PCBs. The potential risk of effects triggered by elevated PCB concentrations was assessed in an individual-based model. A risk of severe decline in population size is projected for the three populations in the next 100 years, especially in SE Brazil, varying between 67 and 99%.

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“…Santos et al 2010;Possatto et al 2016;Moura et al 2021), but it can also be related to behavioural tactics and health conditions (Van Bressem et al 2009a;Domit 2010). Recent studies suggest that dolphins more exposed to anthropogenic impacts have a greater chance of being severely affected by a viral epidemic than those less exposed (Collier et al 2020;Manhães et al 2021), possibly because of a depressed immune response and their poorer health. In addition, as other species of coastal dolphins, these dolphins may have skin lesions and lesions related to trauma caused by interactions with fishing nets or vessel collision (Chan and Karczmarski 2019).…”

Section: Discussionmentioning

confidence: 99%

“…Throughout their distribution, Guiana dolphins are exposed to several human activities. Off the Brazilian coast, for instance, they are often threatened by vessel collision (Domiciano et al 2016), entanglement and incidental mortality in fishing gear (Moura et al 2014;Domiciano et al 2016), bioaccumulation of chemical compounds (Dorneles et al 2008(Dorneles et al , 2020Lailson-Brito et al 2010;Vidal et al 2020;Manhães et al 2021;Trevizani et al 2021), and exposure to emerging diseases (Sacristán et al 2018;Sanchez-Sarmiento et al 2019;Groch et al 2020). These cumulative anthropogenic impacts may cause injuries (Domiciano et al 2016) and health disorders, such as immune depression (Moura et al 2014;Domiciano et al 2016;Manhães et al 2021), poor body condition (Reif et al 2009;Van Bressem et al 2009a, b;Domiciano et al 2016), a higher prevalence of skin lesions and infectious diseases (Van Bressem et al 2009a;Groch et al 2014;Seade et al 2017;Sacristán et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Health conditions of Guiana dolphins facing cumulative anthropogenic impacts

et al. 2022

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Coastal areas are associated with anthropogenic activities and stressors that can expose the marine fauna to negative cumulative impacts. Apex predators, such as dolphins, can flag the quality of their environment through health parameters such as cutaneous and body conditions. We examined the potential relationship between environmental conditions and health parameters of Guiana dolphins around a port and a conservation unit within the Paranaguá Estuarine Complex, southern Brazil. During boat surveys between July 2018 and April 2019 covering both areas, we measured environmental parameters, photographed dolphins to infer their health condition and the frequency of use of the estuary. In total, 204 individual Guiana dolphins were photo-identified, 52 of which were seen in both years. In general, dolphins showed poor body condition (76% classified as emaciated or thin in 2018, and 79% in 2019), diverse cutaneous conditions (four types of lesions suggestive of an infectious aetiology, two conditions suggestive of traumatic events of anthropogenic origin, and two anomalous pigmentation) and a high prevalence of such cutaneous conditions (85% in 2018, 70% in 2019). Most individuals maintained their body and cutaneous conditions between the two years. There were no clear differences between the port and the conservation areas in terms of environmental conditions, frequency of use and health conditions of individual dolphins, suggesting that dolphins inhabiting this estuarine complex are exposed to potential cumulative impacts, such as pollutants, noise and habitat degradation. This study provides baseline information on some health parameters of Guiana dolphins in southern Brazil and highlights the need for systematic, long-term health assessment of Guiana dolphin populations to guide conservation actions to safeguard this vulnerable species.

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Changes in mercury distribution and its body burden in delphinids affected by a morbillivirus infection: Evidences of methylmercury intoxication in Guiana dolphin

Cited by 23 publications

References 86 publications

Fecal Methylmercury Correlates With Gut Microbiota Taxa in Pacific Walruses (Odobenus rosmarus divergens)

Fecal Methylmercury Correlates With Gut Microbiota Taxa in Pacific Walruses (Odobenus rosmarus divergens)

Long-Term Consequences of High Polychlorinated Biphenyl Exposure: Projected Decline of Delphinid Populations in a Hotspot for Chemical Pollution

Health conditions of Guiana dolphins facing cumulative anthropogenic impacts

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