Alexandre F. Azevedo

First Determination of UV Filters in Marine Mammals. Octocrylene Levels in Franciscana Dolphins

Most current bioexposure assessments for UV filters focus on contaminants concentrations in fish from river and lake. To date there is not information available on the occurrence of UV filters in marine mammals. This is the first study to investigate the presence of sunscreen agents in tissue liver of Franciscana dolphin (Pontoporia blainvillei), a species under special measures for conservation. Fifty six liver tissue samples were taken from dead individuals accidentally caught or found stranded along the Brazilian coastal area (six states). The extensively used octocrylene (2-ethylhexyl-2-cyano-3,3-diphenyl-2-propenoate, OCT) was frequently found in the samples investigated (21 out of 56) at concentrations in the range 89-782 ng·g(-1) lipid weight. São Paulo was found to be the most polluted area (70% frequency of detection). Nevertheless, the highest concentration was observed in the dolphins from Rio Grande do Sul (42% frequency of detection within that area). These findings constitute the first data reported on the occurrence of UV filters in marine mammals worldwide.

Anthropogenic and naturally-produced organobrominated compounds in marine mammals from Brazil

Liver samples from 51 cetaceans, comprising 10 species, stranded between 1994 and 2006 in a highly industrialized and urbanized region in Southeast Brazil, were analyzed for polybrominated diphenyl ethers (PBDEs) and methoxylated-PBDEs (MeO-PBDEs). A concentration range of PBDEs (3-5960ng/g lw) similar to that observed in Northern Hemisphere dolphins was found. MeO-PBDE concentrations in continental shelf (CS) dolphins from Brazil are among the highest detected to date in cetaceans (up to 250microg/g lw). Higher SigmaMeO-PBDE concentrations were measured in CS and oceanic dolphins than in estuarine dolphins. The SigmaPBDE/SigmaMeO-PBDE ratio varied significantly ranging from a mean value of 7.12 to 0.08 and 0.01 for estuarine, CS and oceanic species, respectively. A positive correlation was observed between SigmaPBDE and year of stranding of male estuarine dolphins (Sotalia guianensis), which suggests temporal variation in the exposure. Placental transfer of organobrominated compounds was also evidenced in S. guianensis.

Pyrethroids: a new threat to marine mammals?

The present study constitutes the first investigation to demonstrate pyrethroid bioaccumulation in marine mammals, despite the assumption that these insecticides are converted to non-toxic metabolites by hydrolysis in mammals. Twelve pyrethroids were determined in liver samples from 23 male franciscana dolphins from Brazil. The median concentration values for total pyrethroids were 7.04 and 68.4 ng/g lw in adults and calves, respectively. Permethrin was the predominant compound, contributing for 55% of the total pyrethroids. Results showed a distinct metabolic balance of pyrethroids through dolphin life. High loads are received at the beginning of their lives and, when they reach sexual maturity, these mammals seem to degrade/metabolize pyrethroids. Maternal transfer of these compounds was also evaluated through the analysis of breast milk and placenta samples. Pyrethroids were detected in both matrices, with values between 2.53-4.77 ng/g lw and 331-1812 ng/g lw, respectively. Therefore, for the first time, a study shows mother-to-calf transfer of pyrethroids by both gestational and lactation pathways in dolphins.

Habitat use by marine tucuxis (Sotalia guianensis) (Cetacea: Delphinidae) in Guanabara Bay, south-eastern Brazil

Data on habitat use by marine tucuxis (Sotalia guianensis) were collected in Guanabara Bay (GB), south-eastern Brazil, over a two-year period. Diurnal activities of marine tucuxis were dominated by behaviour related to feeding/foraging (58% of all recorded time). Dolphins spent more time in feeding/foraging activities in the morning with a secondary peak in late afternoon. Dolphins were seen in waters of 2 to 35 m (11.63±6.05; median=12.0). Depths used by S. guianensis groups significantly differed from depths available in GB (Kolmogorov-Smirnov test; Z=5.72; P<0.001). Most groups (69.8%) were sighted in depths between 5.1 and 15.0 m. Dolphins occupied an area of 136.9 km 2 , which represents about 42% of the entire water surface of GB. Individuals selected areas within GB and avoided the most degraded ones, which suggests that habitat degradation may affect S. guianensis distribution. Diurnal distances travelled by individuals ranged from 3.3 to 27.2 km in a same day. Dolphins found in main channel and adjacent waters moved along the north-south axis of GB throughout the day and covered distances three times greater than dolphins which concentrated their activities in north-eastern areas.

Whistles of tucuxi dolphins (Sotalia fluviatilis) in Brazil: Comparisons among populations

A quantitative and comparative analysis of the acoustic whistles parameters of tucuxi dolphins (Sotalia fluviatilis) from eight areas in Brazilian waters were conducted. Tucuxi produced mainly upsweep whistles, and despite their similar characteristics to other delphinids, whistles were shorter and less complex in shape. Some signals had fundamental frequency components above 24 kHz, and a broader band system may be useful in further studies concerning tucuxi whistles. The frequency parameters of the whistles had the lowest variation coefficients, whereas the duration and number of inflections had the highest variation coefficients. About 65% of all whistles had common characteristics between study localities, but SF, MinF, MeF, F1/4, F1/2, and F3/4 increased in frequency from southern to northern populations. The magnitude of the whistle characteristics variation was comparatively smaller between adjacent sites areas than between nonadjacent ones. However, for some pairwise comparisons the whistles were more similar between nonadjacent areas than between adjacent ones, indicating that other factors besides genetic and mixing affected tucuxi whistle characteristics. Only a few numbers of whistle variables were significantly different between adjacent areas and the parameter ranges of whistles overlapped, which made it difficult to discriminate whistles between adjacent tucuxi populations.

High organochlorine accumulation in blubber of Guiana dolphin, Sotalia guianensis, from Brazilian coast and its use to establish geographical differences among populations

Blubber samples from 33 Guiana dolphins (Sotalia guianensis) from three estuaries (Guanabara, Sepetiba/Ilha Grande and Paranaguá Bays) of Southern and Southeastern Brazil were analyzed for organochlorine compounds (DDTs, PCBs and HCB). The sampled individuals were incidentally captured in gillnet fishery between 1995 and 2005. The concentrations (in ng/g lipids) varied from 652 to 23 555 for SigmaDDT; from 765 to 99 175 for SigmaPCB; and from <4.4 to 156 for HCB. The results have shown that cetaceans from Brazil present organochlorine concentrations that are comparable to those reported for highly industrialized regions of Northern Hemisphere. Using discriminant analysis it was possible to verify that the dolphin populations from the three bays present different organochlorine accumulation patterns. This feature allows the use of this set of pollutants as an auxiliary tool for identification of different populations of the species off Brazilian Coast.

Mercury-selenium relationships in liver of Guiana dolphin: the possible role of Kupffer cells in the detoxification process by tiemannite formation.

Top marine predators present high mercury concentrations in their tissues as consequence of biomagnification of the most toxic form of this metal, methylmercury (MeHg). The present study concerns mercury accumulation by Guiana dolphins (Sotalia guianensis), highlighting the selenium-mediated methylmercury detoxification process. Liver samples from 19 dolphins incidentally captured within Guanabara Bay (Rio de Janeiro State, Brazil) from 1994 to 2006 were analyzed for total mercury (THg), methylmercury (MeHg), total organic mercury (TOrgHg) and selenium (Se). X-ray microanalyses were also performed. The specimens, including from fetuses to 30-year-old dolphins, comprising 8 females and 11 males, presented high THg (0.53–132 µg/g wet wt.) and Se concentrations (0.17–74.8 µg/g wet wt.). Correlations between THg, MeHg, TOrgHg and Se were verified with age (p<0.05), as well as a high and positive correlation was observed between molar concentrations of Hg and Se (p<0.05). Negative correlations were observed between THg and the percentage of MeHg contribution to THg (p<0.05), which represents a consequence of the selenium-mediated methylmercury detoxification process. Accumulation of Se-Hg amorphous crystals in Kupffer Cells was demonstrated through ultra-structural analysis, which shows that Guiana dolphin is capable of carrying out the demethylation process via mercury selenide formation.

Fisheries and conflicts in Guanabara Bay, Rio de Janeiro, Brazil

A despeito da magnitude da poluicao de origem domestica e industrial, a producao de pescado registrado em diferentes pontos de desembarque na Baia de Guanabara, entre abril de 2001 e marco de 2002, foi ligeiramente superior a 19.000 t, correspondendo em valor a US

Evaluation of cetacean exposure to organotin compounds in Brazilian waters through hepatic total tin concentrations.

4.8 milhoes. Quando se considera apenas o pescado direcionado para o mercado fresco, a captura total alcancou cerca de 6.300 t e um valor de US

Natural and anthropogenically-produced brominated compounds in endemic dolphins from Western South Atlantic: another risk to a vulnerable species.

3,7 milhoes. Somente algumas poucas especies alcancam densidades expressivas compativeis com as pescarias comerciais. Entre os pequenos pelagicos, a sardinha boca-torta e a sardinha verdadeira sao as especies dominantes, enquanto para as demersais, a corvina, a tainha e os bagres perfazem a maior parte das capturas. As pescarias para o caranguejo, nos manguezais, e a coleta de mexilhoes nos costoes rochosos da entrada da baia e ilhas adjacentes sao, tambem, importantes. A ausencia de estatisticas pesqueiras previas ao vazamento de 1,3 milhao de litros de oleo, em janeiro de 2000, levou a reivindicacao de indenizacoes, por parte das organizacoes representativas dos pescadores, de valores correspondentes a cerca de 50 anos de producao de pescado na baia. Um sistema de coleta de dados pode ser estabelecido de forma participativa com as associacoes de pescadores locais. As pescarias relativamente estaveis na baia sugerem que inferencias razoaveis podem ser obtidas sem que, necessariamente, se tenha uma cobertura completa de todos os pontos de desembarque.