PAHs in franciscana dolphins from the Southwestern Atlantic Ocean: Concentration and maternal transfer assessments.

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds ubiquitous in the environment and known for their toxic, mutagenic, and carcinogenic effects. These compounds can bioaccumulate in the biota and be transferred through trophic webs. The franciscana dolphin (Pontoporia blainvillei), as top predators, can be an environmental sentinels. Thus, this study aimed to provide data about PAHs concentration in their hepatic tissue collected on the coast of Espírito Santo (Franciscana Management Area, FMA Ia), Rio de Janeiro (FMA IIa), and São Paulo states (FMA IIb), in Southeastern Brazil. PAHs were detected in 86 % of franciscana dolphins (n = 50). The highest ∑PAHsTotal median concentration was reported in FMA Ia followed by FMA IIb and FMA IIa (1055.6; 523.9, and 72.1 ng.g-1 lipid weight, respectively). Phenanthrene was detected in one fetus and two neonates, showing maternal transfer of PAHs in these dolphins. Evaluating PAHs with potential toxic effects is of utmost importance for the conservation of a threatened species.

Survey of selected viral agents (herpesvirus, adenovirus and hepatitis E virus) in liver and lung samples of cetaceans, Brazil.

Hepatic and pulmonary lesions are common in cetaceans, despite their poorly understood viral etiology. Herpesviruses (HV), adenoviruses (AdV) and hepatitis E virus (HEV) are emerging agents in cetaceans, associated with liver and/or pulmonary damage in mammals. We isolated and molecularly tested DNA for HV and AdV (n = 218 individuals; 187 liver and 108 lung samples) and RNA for HEV (n = 147 animals; 147 liver samples) from six cetacean families. All animals stranded or were bycaught in Brazil between 2001 and 2021. Positive-animals were analyzed by histopathology. Statistical analyses assessed if the prevalence of viral infection could be associated with the variables: species, family, habitat, region, sex, and age group. All samples were negative for AdV and HEV. Overall, 8.7% (19/218) of the cetaceans were HV-positive (4.8% [9/187] liver and 11.1% [12/108] lung), without HV-associated lesions. HV-prevalence was statistically significant higher in Pontoporiidae (19.2%, 10/52) when compared to Delphinidae (4.1%, 5/121), and in southeastern (17.1%, 13/76)-the most industrialized Brazilian region-when compared to the northeastern region (2.4%, 3/126). This study broadens the herpesvirus host range in cetaceans, including its description in pygmy sperm whales (Kogia breviceps) and humpback whales (Megaptera novaeangliae). Further studies must elucidate herpesvirus drivers in cetaceans.

Spatial trends of trace elements bioaccumulation in the most endangered dolphin from the Southwestern Atlantic Ocean: The franciscana (Pontoporia blainvillei).

Trace elements bioaccumulation patterns can be an important tool to assess differences among cetaceans' populations. In this work, their use as potential chemical markers to differentiate franciscanas (Pontoporia blainvillei) populations was evaluated. Franciscanas were collected from three states in southeastern Brazil, which comprise three different Franciscana Management Areas (FMAs): Espírito Santo (FMA Ia), southern Rio de Janeiro (FMA IIa), and central São Paulo (FMA IIb). The concentrations of As, Cd, Cu, Fe, Hg, Mn and Zn were determined in the muscle, liver and kidney of the animals. Cadmium was the most valuable chemical marker to differentiate stocks, separating at least FMA IIa from the others. The higher Cd levels in FMA IIa, along with dietary information, indicate that the predominant consumption of cephalopods by this population is the main reason for the differences found. Additionally, environmental characteristics of the areas should also be considered as divergent sources of trace elements. Our findings suggest that non-essential trace elements, such as Cd, can be successful markers to differentiate populations. The Mn concentrations in FMA Ia raised concern and must be carefully monitored, as well as other elements that compose the iron ore tailings that have impacted the Espírito Santo coastal area. Additionally, this is the first study to report trace element concentration in the franciscanas from FMA IIa (southern Rio de Janeiro). Trace element concentrations found in franciscanas may represent different contamination levels in their preys and environments, which might pose specific threats to distinct populations. Therefore, our findings are important to characterize and differentiate franciscana populations and to guide precise management and conservation actions for the distinct stocks of this endangered species.

Genetic diversity and population structure of Synthesium pontoporiae (Digenea, Brachycladiidae) linked to its definitive host stocks, the endangered Franciscana dolphin, Pontoporia blainvillei (Pontoporiidae) off the coast of Brazil and Argentina.

Pontoporia blainvillei (Gervais and d'Orbigny, 1844) is an endangered small cetacean endemic to South America with four Franciscana Management Areas (FMA) recognized as different population stocks. The role of the intestinal parasite Synthesium pontoporiae (Digenea: Brachycladiidae) as a possible biological marker to differentiate P. blainvillei stocks was evaluated using nuclear and mitochondrial DNA markers. Internal transcribed sequence 1 and 2 (ITS1 and ITS2) regions of S. pontoporiae did not show intraspecific variability. The mitochondrial NADH dehydrogenase subunit 3 (ND3) and cytochrome oxidase subunit I (COI) gene sequences suggested lack of population structure in S. pontoporiae and population expansion. The apparent panmixia of S. pontoporiae may be due to the high mobility of one or more of its intermediary hosts. Alternatively, it may be due to the small sample size. This result is incongruent with the previously proposed FMA.

Renal lesions in cetaceans from Brazil.

This study reports the occurrence of renal lesions in cetaceans from the coast of Brazil subjected to necropsy examination between 1996 and 2011. The animals (n = 192) were by-caught in fishing nets, were found dead on beaches or died despite attempted rehabilitation. Kidney samples were evaluated grossly and microscopically and, depending on the histopathological findings, immunohistochemical and ultrastructural analyses were conducted. Due to autolysis, a diagnosis was reached in only 128 animals, of which 82 (64.1%) had kidney lesions. Cystic renal disease was the most common lesion observed in 34 cases (26.6%) and these were classified as simple cysts in eight cases (6.3%), polycystic kidney disease in one rough-toothed dolphin (Steno bredanensis), secondary glomerulocystic disease in 16 cases (12.5%) and primary glomerulocystic disease in nine cases (7%). Other lesions included membranous glomerulonephritis (28 cases; 21.9%), membranoproliferative glomerulonephritis (20 cases; 15.6%), lymphoplasmacytic interstitial nephritis (21 cases; 16.4%), lipidosis (19 cases; 14.8%), glomerulosclerosis (8 cases; 6.3%) and pyogranulomatous nephritis(five cases; 3.9%); two of the later were associated with the migration of nematode larvae. Additionally, tubular adenoma was identified in a Franciscana (Pontoporia blainvillei). The pathological implications of these lesions are discussed according the cause of death, age or sex of the animals. Furthermore, the lesions were compared with those of other marine and terrestrial mammals, including man.

PBDE levels in franciscana dolphin (Pontoporia blainvillei): temporal trend and geographical comparison.

Total PBDE concentrations determined in archived blubber samples from franciscana dolphins (Pontoporia blainvillei) unintentionally captured in the Brazilian coastal region off Rio Grande do Sul State (FMA III) between 1994 and 2004 (n = 73) ranged from 7.9 to 65 ng g(-1) lipid weight in mature males, with an increase over the ten-year period. Total PBDE concentrations in blubber samples collected from the FAM II (n = 41) between 2002 and 2005 were higher (67.8 to 763.7 ng g(-1)lw) than those from FMA III. This is possibly due to the proximity to important industrial development sites in the state of São Paulo. Despite the differences in total concentrations, PBDE profiles were comparable and the PBDE concentrations decreased in the following order BDE 47>BDE99>BDE 100 for both FMA and for males and females as well as adults, juveniles and pups.

Dechlorane-related compounds in franciscana dolphin (Pontoporia blainvillei) from southeastern and southern coast of Brazil.

Concentrations of Dechlorane (Dec) 603 (0.75 ng/g lipid weight (lw); mean) and Dec 602 (0.38 ng/g lw; mean) were quantified in more than 95% of the franciscana (Pontoporia blainvillei) dolphin samples, whereas the frequency of detection decreased to 75% for Dechlorane Plus (DP) (1.53 ng/g lw, mean). The presence of Chlordene Plus (CP) was also observed (0.13 ng/g lw, mean) in half of the samples. On the contrary, Dec 604, decachloropentacyclooctadecadiene (aCl(10)DP), and undecachloropentacyclooctadecadiene (aCl(11)DP) concentrations were below the limit of quantifications in all cases. To the best of our knowledge, this is the first article reporting the presence of Dec 603, Dec 602, and CP in mammals. For comparative purposes, levels of Mirex, polybrominated diphenyl ethers (PBDEs), and decabromodiphenylethane (DBDPE) are also reported. Considering geographic distribution evaluation together with the strong positive correlations found between DP and PBDEs (r(s) = 0.63; p < 0.01), highly anthropogenic areas were identified as potential sources of these chemicals in this dolphin species. However, local sources for Dec 602, 603, Mirex, CP, and DBDPE were not found indicating that in this case historical use and/or atmospheric transport and deposition may play an important role in their fate.

PBDEs in the blubber of marine mammals from coastal areas of São Paulo, Brazil, southwestern Atlantic.

Limited information is available in the literature on the levels of brominated flame retardants in the southern hemisphere. This study presents concentrations of polybrominated diphenyl ethers (PBDEs) in the blubber of small cetaceans from the coast of São Paulo (Brazil), southwestern Atlantic. PBDE levels were highest in Stenella frontalis (770 ng g(-1) lipid) followed by Steno bredanensis (475 ng g(-1) lipid), Sotalia guianensis (65.6 ng g(-1) lipid), Tursiopstruncatus (64.2 ng g(-1) lipid) and Pontoporia blainvillei (60.3 ng g(-1) lipid). In general, continental shelf individuals exhibited higher contamination than inshore animals. This might be related to larger prey items consumed by continental shelf dolphins. The pattern of contamination indicates that Penta-BDE commercial mixtures are a major source of PBDEs to top predators in the southwestern Atlantic. Congeners found in Octa-BDE formulations were not detected in the investigated animals.

Levels of persistent organic pollutants and residual pattern of DDTs in small cetaceans from the coast of São Paulo, Brazil.

The State of São Paulo is the most developed area in Brazil and was impacted by persistent organic pollutants for several decades. This study investigated organochlorines in five species of small cetaceans (Pontoporia blainvillei, Stenella frontalis, Sotalia guianensis, Tursiops truncatus and Steno bredanensis) found dead along the coast of São Paulo between 1997 and 2003. DDTs (15.9 µg g(-1) lipid; mean for all pooled individuals) and PCBs (8.08 µg g(-1)) exhibited the highest concentrations in the animals, reflecting large amounts formerly used in Brazil. Lower levels of mirex (0.149 µg g(-1)), HCB (0.051 µg g(-1)), CHLs (0.008 µg g(-1)) and HCHs (0.007 µg g(-1)) were detected in all species. Residual pattern of DDTs in dolphins suggests that o,p'-DDT is more recalcitrant than p,p'-DDT in the body of the animals and/or the environment. In contrast to p,p'-DDT, residues of o,p'-DDT seem to be preferentially converted into o,p'-DDD rather than o,p'-DDE.