Trophic Chain Organochlorine Pesticide Contamination in a Highly Productive Upwelling Area in Southeastern Brazil.

Organochlorine pesticides (OCP) are legacy anthropogenic compounds known to persist for several years in the environment. The continuous use of some OCP, such as DDT, after restrictions in developing countries are cause of concern, due to their deleterious effects to marine life and humans. Studies assessing OCP contamination in coastal environments are still scarce in South America and there is a need to understand the impacts from trophic chain accumulation of these pollutants in marine life. In this study, we have assessed OCP levels in muscle and liver and estimated the biomagnification factor in several upwelling system trophic chain members, including fish, squid, and marine mammal from Southeastern Brazil. DDT degradation product DDE was the OCP detected in the highest concentrations in Franciscana dolphins (Pontoporia blainvillei), 86.4 ng·g-1 wet weight, and fish muscle and liver. In general, higher OCP levels were found in liver than in muscle, except for croaker. Biomagnification factors (BMF) of OCP in the top predator P. blainvillei and the carnivorous cutlass fish (Trichiurus lepturus) were on average between 0.2 and 1.8. Continued OCP monitoring in this region is warranted to better understand the distribution and fate of these compounds over time, with the goal to establish strategies for the conservation of local dolphin species and to assess human health risks from local coastal region populations.

Density and composition of surface and buried plastic debris in beaches of Senegal.

Debris poses a series of problems to marine life and human well-being. However, estimates of density and characteristics of debris found on beach surfaces and buried in the sand are patchy on a global scale and absent for West Africa. Here we investigate the density of surface and buried debris accumulated in two beaches with contrasting levels of urbanisation in Senegal, West Africa. We also describe type, colour, weight, size, and possible source of the 1766 items collected. The average density of debris buried at a depth of 10 cm (48.75 items/m2) was 25 times higher than that observed at the surface (1.92 items/m2). Plastics accounted for 97.62% of the items. Plastic bags and clothing plastic were the most common types, whereas white and transparent were the most common colours. Most items originated from mixed sources, i.e. beach users and land-based sources (51.30%). Debris density in the urbanised site was 20 times higher than that in the non-urbanised site. Debris density can, therefore, be largely underestimated when sampling only on the beach surface. Our study provides the first findings for future research on beach debris in Senegal.

Total and subcellular Ti distribution and detoxification processes in Pontoporia blainvillei and Steno bredanensis dolphins from Southeastern Brazil.

Titanium (Ti), used in many dailyuse products, such as shampoos and sunscreen filters, in the form of TiO2 nanoparticles (NPs), may elicit adverse marine biota effects. Marine mammal Ti data is scarce, and subcellular distribution and detoxification information is non-existent. Ti concentrations and metalloprotein detoxification in Pontoporia blainvillei and Steno bredanensis dolphins from Southeastern Brazil were assessed. Metallothionein (MT) concentrations were determined spectrophotometrically, total and subcellular Ti, by ICP-MS and detoxification, by HPLC-ICP-MS. Ti detoxification occurred through MT complexation. Statistical Ti-MT associations were observed in S. bredanensis liver, indicating TiO2 NPs contamination, as Ti binds to MT only as NPs. MT-Ti correlations were observed for both the coastal (P. blainvillei) and offshore (S. bredanensis) dolphins, evidencing oceanic TiO2 diffusion. Ti detoxification through binding to reduced glutathione occurred in both species. Thermostable subcellular fractions are a valuable tool for cetacean Ti detoxification assessments and should be applied to conservation efforts.

Confidence intervals and sample size for estimating the prevalence of plastic debris in seabird nests.

Evidence is accumulating about the impacts of plastics on marine life. The prevalence of plastics in seabird nests has been used as an indicator of levels of this pollutant in the ocean. However, the lack of a framework for defining sample sizes and errors associated with estimating the prevalence of plastic in nests prevents researchers from optimising time and reducing impacts of fieldwork. We present a method to determine the confidence intervals for the prevalence of debris in seabird nests and provide, for the first time, information on the prevalence of these items in nests of the Hartlaub's gull Larus hartlaubii, the African penguin Spheniscus demersus, the great white pelican Pelecanus onocrotalus, and the white-breasted cormorant Phalacrocorax lucidus in South Africa. The method, based on observations and resampling simulations and tested here for nests of 12 seabird species from 15 locations worldwide, allows for straightforward hypothesis testing. Appropriate sample sizes can be defined by combining this method with a Bayesian approach. We show that precise estimates of prevalence of debris in nests can be obtained by sampling around 250 nests. Smaller sample sizes can be useful for obtaining rough estimates. For the Hartlaub's gull, the African penguin, the great white pelican, and the white-breasted cormorant, debris were present in 0.75%, 3.00%, 6.41%, and 25.62% of the respective nests. Our approach will help researchers to determine errors associated with the prevalence of debris recorded in seabird nests and to optimise time and costs spent collecting data. It can also be applied to estimate confidence intervals and define sample sizes for assessing prevalence of plastic ingestion by any organism.

Subcellular metal distributions and metallothionein associations in rough-toothed dolphins (Steno bredanensis) from Southeastern Brazil.

Metals are subject to internal subcellular compartmentalization, altering their bioavailability. Thus, subcellular metal assessments are crucial in biomonitoring efforts. Metal distribution in three subcellular fractions (insoluble - ISF, thermolabile - TLF and thermostable - TSF) were determined by ICP-MS in Steno bredanensis specimens from Southeastern Brazil. Associations between metals, metallothionein (MT) and reduced glutathione (GSH) were also investigated. Differential metal-detoxification mechanisms were observed. MT detoxification was mostly noted for As, Cd, and Pb, while Cu, Cr, Hg, Ni, Se and Ti displayed lower MT-associations. Fe, Zn and Se, on the other hand, were poorly associated to MT, and mostly present in the ISF, indicating low bioavailability. This is the first report on subcellular Sn and Ti distribution in cetaceans and the first in this species in Brazil. Potential protective roles of essential metals against toxic elements are postulated. This study indicates that important biochemical detoxification information is obtained through subcellular fraction analyses in marine mammals.

An assessment of PCB and PBDE contamination in two tropical dolphin species from the Southeastern Brazilian coast.

PCBs and PBDEs were determined in two dolphin species, Sotalia guianensis and Steno bredanensis, from an upwelling system off the Central-northern coast of Rio de Janeiro, Brazil. PCB levels varied from 0.040 to 0.75 µg g(-1) lw in muscles and from 0.022 to 1.32 µg g(-1)lw in liver samples from S. guianensis. In S. bredanensis, values varied from 0.085 to 11.3 µg g(-1) lw in muscles and from 0.024 to 18.6 µg g(-1) lw in livers. PCB-138, -153 and -180 were the major PCB congeners detected in both species, while BDE-47 was the predominant PBDE congener found in both species. Higher concentrations in S. bredanensis were possibly related to the different feeding habits for both delphinid species. These results contribute to extend the database on organic contamination in cetaceans from the southern hemisphere, understanding their distribution and environmental fate in Southeastern Brazil.

Assessment of trace elements, POPs, (210)Po and stable isotopes ((15)N and (13)C) in a rare filter-feeding shark: The megamouth.

With less than 60 records being reported worldwide, the megamouth (Megachasma pelagios) is today one of the least known shark species inhabiting our oceans. Therefore, information concerning the biology and ecology of this enigmatic organism is very scarce and limited to feeding behaviour and preferred habitat. The present work reports new data on the concentrations of trace elements, organic mercury, POPs and (210)Po in hepatic and muscular tissues of a specimen found stranded in the southeastern coast of Brazil. Additionally, we provide new evidence based on stable isotope analysis (δ(15)N and δ(13)C) confirming the preference for the pelagic habitat and the zooplanktivorous feeding behaviour of the megamouth. These results are consistent with the low concentrations of organic pollutant compounds and other elements measured in our samples.

The Manx shearwater (Puffinus puffinus) as a candidate sentinel of Atlantic Ocean health.

INTRODUCTION: Seabirds have been historically used to monitor environmental contamination. The aim of the present study was to test the suitability of a species belonging to the Procellariiformes group, the Manx shearwater, Puffinus puffinus, as a sentinel of environmental health, by determining contaminant levels (trace metals and organochlorine compounds) from carcass tissues and by isolating Vibrio spp. and Aeromonas spp. from live specimens. To this end, 35 Puffinus puffinus carcasses wrecked on the north-central coast of the state of Rio de Janeiro, Brazil, and two carcasses recovered in Aracruz, on the coast of the state of Espírito Santo, Brazil, were sampled, and fragments of muscle and hepatic tissues were collected for contaminant analyses. Swabs from eleven birds found alive at the north-central coast of Rio de Janeiro were collected for isolation of the aforementioned bacteria. RESULTS: THE AVERAGE CONCENTRATION IN DRY WEIGHT (DW) OF THE TRACE METALS WERE: mercury 7.19 mg kg(-1)(liver) and 1.23 mg kg(-1) (muscle); selenium 34.66 mg kg(-1) (liver) and 7.98 mg kg(-1) (muscle); cadmium 22.33 mg kg(-1) (liver) and 1.11 mg kg(-1) (muscle); and lead, 0.1 mg kg(--1) (liver) and 0.16 mg kg(-1) (muscle). Organochlorine compounds were detected in all specimens, and hexachlorbiphenyls, heptachlorbiphenyls and DDTs presented the highest levels. Regarding microbiological contamination, bacteria from the Vibrio genus were isolated from 91% of the analyzed specimens. Vibrio harveyi was the predominant species. Bacteria from the Aeromonas genus were isolated from 18% of the specimens. Aeromonas sobria was the only identified species. CONCLUSIONS: The results indicate that Puffinus puffinus seems to be a competent ocean health sentinel. Therefore, the monitoring of contaminant levels and the isolation of public health interest bacteria should proceed in order to consolidate this species importance as a sentinel.

(210)Polonium and (210)lead content of marine birds from Southeastern Brazil.

In this study, we report the (210)Po and (210)Pb concentrations of bone, muscle and liver samples that were obtained from twelve different marine bird species stranded on beaches in the central-north region of Rio de Janeiro State. Both radionuclides were highly concentrated in the liver samples; however, the lowest mean (210)Po/(210)Pb activity ratio (1.3) was observed in bones compared with liver and muscle (16.8 and 13.8, respectively). Among the species that were studied, Fregata magnificens, with a diet based exclusively on fish, had the lowest (210)Pb and (210)Po concentrations and the lowest (210)Po/(210)Pb activity ratio. The (210)Po concentrations in Puffinus spp. liver samples followed a log-normal distribution, with a geometric mean of 300 Bq kg(-1)wet weight. Only two references pertaining to (210)Po in marine birds were found in a Web of Science search of the literature, and each study reported a different concentration value. The values determined in this experiment are consistent with those in one of the previous studies, which also included one of the species studied in this work. No values for (210)Pb in marine birds have been published previously.

Guiana dolphins (Sotalia guianensis) as marine ecosystem sentinels: ecotoxicology and emerging diseases.

Guiana dolphins (Sotalia guianensis) are small cetaceans that inhabit coastal regions down to a 50 m depth. As a coastally distributed species, they are exposed to a variety of human-induced risks that include passive fishing nets, persistent environmental pollution, and emerging diseases. As a top predatorS. guianensis occupies an important ecological niche in marine ecosystems. However, this niche also exposes this dolphin to extensive biomagnification of marine contaminants that may accumulate and be stored throughout their life of about 30 years.In this paper, we have compiled available data on the Guiana dolphin as regards its exposure to chemical pollutants, pathogenic microbes, infectious diseases, and injuries caused by interactions with passive fishing gears. Our analysis of the data shows that Guiana dolphins are particularly sensitive to environmental changes.Although the major mortal threat to dolphins results from contact with fishing other human-related activities in coastal zones also pose risks and need more attention.Such human-related risks include the presence of persistent toxicants in the marine environment, such as PCBs and PBDEs. Residues of these chemicals have been detected in Guiana dolphin's tissues at similar or higher levels that exist in cetaceans from other known polluted areas. Another risk encountered by this species is the non lethal injuries caused by fishing gear. Several incidents of this sort have occurred along the Brazilian coast with this species. When injuries are produced by interaction with fishing gear, the dorsal fin is the part of the dolphin anatomy that is more affected, commonly causing severe laceration or even total loss.The Guiana dolphins also face risks from infectious diseases. The major ones thus far identified include giardiasis, lobomycosis, toxoplasmosis, skin and skeletal lesions. Many bacterial pathogens from the family Aeromonadaceae and Vibrionaceae have been isolated from Guiana dolphins. Several helminth species have also been observed to affectS. guianensis. These results suggest a vulnerability of this species to environmental disturbances. Moreover, there is some evidence that the effects of some infectious diseases may be enhanced from stress caused by habitat impairment. For example, certain diseases and pathogenic organisms in S.guianensis may be associated with the high levels of endocrine-disruptor contaminants(e.g., PCBs; DDTs; PBDEs) that have been detected in marine waters.Although the data available on S. guianensis is growing, most of the work has been focused on a small portion of the species total area of distribution. Most studies,to date, have been carried out in the Southern region of the distribution, and in north eastern Brazil. Few studies have been conducted in the northern region of the South America or in Central America. Therefore, future studies should be conducted that address the heterogeneity of this species total distribution.The biology and ecology of the Guiana dolphin renders this species potentially useful as a sentinel species for detecting environmental changes, such as chemical and biological pollution. Research about this dolphin is encouraged as a way to assess what coastal environmental changes have occurred and to continue evaluating the health status of this vulnerable species in a changing environment.

Small cetaceans found stranded or accidentally captured in southeastern Brazil: bioindicators of essential and non-essential trace elements in the environment.

Essential (Cu, Mn, Se and Zn) and non-essential (Cd and Hg) elements were analyzed in the hepatic tissue of 22 individuals of seven different species of small cetaceans (Feresa attenuata; Orcinus orca; Pontoporia blainvillei; Sotalia guianensis; Stenella frontalis; Steno bredanensis; Tursiops truncatus) accidentally caught in fishing nets or found stranded along the northern coast of the state of Rio de Janeiro, Brazil, between 2001 and 2010. Atlantic spotted dolphin (S. frontalis) showed the highest levels of Cd (20.23µgg(-1), dry weight), while rough-toothed dolphin (S. bredanensis) showed the highest levels of Hg (825.9µgg(-1)dw) and Se (221.9µgg(-1)dw). Killer whale (O. orca) presented the highest levels of Cu (64.80µgg(-1)dw) and Zn (2220µgg(-1)dw), and Guiana dolphin (S. guianensis), the highest level of Mn (13.05µgg(-1)dw). Cu, Hg, Mn and Zn in the hepatic tissue of killer whale (O. orca), Cu, Hg, Mn, Se and Zn in the hepatic tissue of rough-toothed dolphin (S. bredanensis) and Cd and Zn in the hepatic tissue of Guiana dolphin (S. guianensis) were significantly higher when compared to other studies with these species around the world. No significant correlations were observed between element accumulation and sex, sexual maturity and body length. An analysis of the interelemental relationships in the Guiana dolphin specimens showed strong positive correlations between Cd and Se, Cu and Zn, and Hg and Se. Differences were observed in the bioaccumulation of elements between the analyzed species, probably related to each species feeding habit, and differences between different element concentrations in the different dolphin species were probably due to the preference for certain preys and their bioavailability in the environment. Thus, the bioavailability of the analyzed elements in the marine environment should also be taken in consideration. This study also presents the first data ever reported for pygmy killer whale (F. attenuata) regarding trace element concentrations in hepatic tissue.

Saúde pública e saúde dos oceanos: interface conceitual dos paradigmas e análise de elementos essenciais e não essenciais em organismos marinhos de um ecossistema de ressurgência / Public health and health of the oceans: the conceptual interface paradigms and analysis of essential and nonessential elements in marine organisms in an ecosystem upwelling

Neste estudo foi avaliada a condição de vulnerabilidade ambiental e da saúde humana em decorrência dos impactos e alterações observados nos oceanos nas últimas décadas, incluindo o foco sobre as mudanças climáticas, florações de algas tóxicas, contaminação microbiológica e química nas águas marinhas e bioinvasão de espécies exóticas. Além disso, foi abordada a relação dos valores benéficos que os oceanos proporcionam à saúde e bem-estar da humanidade. Esta primeira fase do estudo mostrou a interface entre o estado de conservação dos oceanos e sua relação com a economia e saúde humana. Mais adiante neste manuscrito foi realizado um estudo sazonal das concentrações de metais tóxicos (Hg, Al e As), micro (Zn, Cu, Fe, Se e Sr) e macronutrientes (Na, K, Ca e Mg) em amostras de músculo de lula (Loligo plei) e peixes marinhos pelágicos (Sardinella brasiliensis, Trichiurus lepturus e Coryphaena hippurus) com importância para a pesca, considerando o fenômeno temporal (inverno e verão) da ressurgência de Cabo Frio. As concentrações de As e Cu ultrapassaram os limites máximos de tolerância para o consumo humano. Foram observadas diferenças sazonais em alguns indivíduos, porém associação antagônica temporal entre as espécies, algumas apresentando concentrações mais elevadas durante o verão enquanto outras mostraram concentrações maiores no inverno para um determinando elemento. Foram encontradas diferenças significativas entre as concentrações detectadas nas diferentes espécies. No geral a lula (L. plei) e a sardinha-verdadeira apresentaram concentrações superiores dos elementos.

Foram detectadas correlações interelementares com destaque para associação entre Mg-Se e Ca-Sr. Um outra abordagem foi empregada com a finalidade de se estudar as concentrações de elementos tóxicos (Hg, Al e As), micronutrientes (Zn, Cu, Fe, Sr e Se) e macronutrientes (Na, K, Ca e Mg) em amostras de mexilhão (Perna perna), lula (Loligo plei), peixes pelágicos (Sardinella brasiliensis, Trichiurus lepturus e Coryphaena hippurus), tartaruga marinha (Chelonia mydas), ave marinha (Sula leucogaster) e mamíferos marinhos, incluindo duas espécies de golfinhos (Tursiops truncatus e Steno bredanensis) e uma espécie de baleia (Balaenoptera brydei). As coletas foram conduzidas na área de influência da ressurgência costeira de Cabo Frio, sendo estas espécies representativas deste hábitat. Foram encontradas diferenças significativas entre as concentrações detectadas nas diversas espécies. Uma distribuição trófica na concentração dos elementos foi percebida para Hg e Fe. Concentrações de Al também foram expressivamente elevadas para as amostras de lula e mexilhão. Foram observadas correlações interelementares significativas entre as espécies avaliadas variando para cada espécie. As concentrações de macronutrientes foram expressivas se comparadas aos demais estudos publicados. Os resultados encontrados mostram que a região de ressurgência de Cabo Frio parece exercer papel importante na biodisponibilização de elementos para a estrutura trófica marinha.

Mercury status of the Amazon Continental Shelf: Guiana dolphins (Sotalia guianensis, Van Benédén 1864) as a bioindicator.

Total mercury (Hg) was analyzed in muscle tissue of 27 accidentally captured Guiana dolphins (Sotalia guianensis) in order to evaluate Hg contamination levels present in the Amazon Continental Shelf, in Amapá state, North Brazil. The samples showed a mean concentration of 0.4 ± 0.16 µg/g wet weight (ww), ranging from 0.07 to 0.79 µg/g ww. As observed in several other cetacean species, Hg concentrations presented positive correlations to body length, related to the capacity to bioaccumulate this element throughout life. Hg concentrations were not significantly different between males (mean = 0.38 µg/g ww; n = 15) and females (mean = 0.42 µg/g ww; n = 12). Concentrations were low when compared to results of studies carried out with small cetaceans in the Northern Hemisphere, and with some previous studies in the south-eastern region of Brazil. In contrast with high Hg concentrations normally detected in river dolphin samples from Amazon River tributaries, our results suggest that the Amazon coast contains low levels of Hg in bioavailable form.

210Polonium content of small cetaceans from Southeastern Brazil.

The (210)Po concentration of muscle and liver samples obtained from dolphins stranded on beaches in the Southeastern region of Rio de Janeiro State was analyzed in the present study. The samples were primarily obtained from "Franciscana" (Pontoporia blainvillei) and "Guiana" dolphins (Sotalia guianensis); however, samples from four other species were also evaluated. The (210)Po concentration of muscle samples obtained from "Franciscana" dolphins (66.7±6.7, n=8)Bq kg(-1)w.w. was greater than that of "Guiana" dolphins (25.3±5.7, n=8)Bq kg(-1)w.w. due to differences in the diets of these species. Alternatively, the (210)Po concentrations of liver samples obtained from different species were statically equivalent. Compared to the results described in the literature, the muscle samples evaluated in the present study displayed lower (210)Po concentrations, except for those obtained from "Franciscana" dolphins, which exhibited similar values. For "Franciscana" and "Guiana" dolphins, a clear relationship between the (210)Po concentration of muscle and liver samples and the size of the dolphin was not observed.

Guiana dolphins (Sotalia guianensis, Van Benédén 1864) as indicators of the bioaccumulation of total mercury along the coast of Rio de Janeiro state, Southeastern Brazil.

Total mercury (Hg) was determined in muscle tissue of 20 Guiana dolphins stranded along the coast of Rio de Janeiro state, Brazil, with a mean of 1.07 µg/g wet weight. Mercury concentrations were positively related to body length, possibly related to the capacity of the dolphins to bioaccumulate this element throughout life. The Hg concentrations were not significantly different between males and females, although females (1.08 µg/g) showed slightly higher levels than males (1.04 µg/g). Concentrations were low when compared to results of studies carried out with small cetaceans in the Northern Hemisphere, and with previous studies in the Southeastern Brazil.

[The interface of public healthcare with the health of the oceans: proliferation of disease, socio-economic impacts and beneficial relationships]. / A interface da saúde pública com a saúde dos oceanos: produção de doenças, impactos socioeconômicos e relações benéficas.

Over the past decades, human activities have had a heavy impact on the marine environment, causing alterations in ecological processes. The relationship between the health of the oceans, human activities and public healthcare is already generally accepted, though the mechanisms involved are still under scientific scrutiny. These relationships include a focus on climate change, toxic algal blooms, microbial and chemical contamination in marine waters and bioinvasion by exotic species. Moreover, there is the beneficial effect of the oceans on human health and wellbeing, such as natural products for the human diet, the development of biomedicine, or simply the satisfaction derived from human recreation, sports and other interactions of humans with oceans. The importance of appreciating the link between public healthcare and the health of the oceans is especially important due to the growing number of people living in coastal areas, mainly in tropical and subtropical regions. The backcloth to this is risk-related human activities that pose a danger to marine environmental health and the increase in the vulnerability of humans and biodiversity and socio-environmental iniquity.

A interface da saúde pública com a saúde dos oceanos: produção de doenças, impactos socioeconômicos e relações benéficas / The interface of public healthcare with the health of the oceans: proliferation of disease, socio-economic impacts and beneficial relationships

Nas últimas décadas, as atividades humanas têm causado forte impacto sobre o ambiente marinho, provocando alterações no seu processo ecológico. A relação entre a saúde dos oceanos, as atividades antropogênicas e a saúde pública já é consenso, entretanto, seus mecanismos ainda estão sob os olhares da ciência. Essas relações incluem o foco sobre as mudanças climáticas, florações de algas tóxicas, contaminação microbiológica e química nas águas marinhas e bioinvasão de espécies exóticas. Além disso, existe a relação dos valores benéficos que os oceanos proporcionam à saúde e bem-estar da humanidade, tais como produtos naturais relevantes para a alimentação humana, o desenvolvimento da biomedicina, ou simplesmente, a satisfação humana derivada da recreação, esportes e outras interações dos seres humanos com os oceanos. A importância de se conhecer a relação entre saúde pública e a saúde dos oceanos dá-se, principalmente, devido ao crescente número de pessoas vivendo em zonas costeiras, nas regiões tropicais e subtropicais, tendo como pano de fundo as atividades antropogênicas produtoras de risco para a saúde do ambiente marinho, aumento da vulnerabilidade do homem, da biodiversidade e da iniquidade socioambiental.

Over the past decades, human activities have had a heavy impact on the marine environment, causing alterations in ecological processes. The relationship between the health of the oceans, human activities and public healthcare is already generally accepted, though the mechanisms involved are still under scientific scrutiny. These relationships include a focus on climate change, toxic algal blooms, microbial and chemical contamination in marine waters and bioinvasion by exotic species. Moreover, there is the beneficial effect of the oceans on human health and wellbeing, such as natural products for the human diet, the development of biomedicine, or simply the satisfaction derived from human recreation, sports and other interactions of humans with oceans. The importance of appreciating the link between public healthcare and the health of the oceans is especially important due to the growing number of people living in coastal areas, mainly in tropical and subtropical regions. The backcloth to this is risk-related human activities that pose a danger to marine environmental health and the increase in the vulnerability of humans and biodiversity and socio-environmental iniquity.

O boto-cinza (Sotalia guianensis) como sentinela da saúde dos ambientes costeiros: estudo das concentrações de mercúrio no estuário Amazônico e costa norte do Rio de Janeiro / Tucuxi Dolphins (Sotalia guianensis) as sentinel for the health of coastal environments: a study of concentrations of mercury in the Amazon estuary and the northern coast of Rio de Janeiro

A contaminação dos oceanos, associada às atividades antrópicas, tem se tornando biodisponível para diversos organismos, entretanto os mais vulneráveis são aqueles situados no topo da cadeia trófica marinha, incluindo o homem e os mamíferos marinhos, mas principalmente os cetáceos costeiros, como o boto-cinza (Sotalia guianensis). Diversos estudos têm indicado que os cetáceos são excelentes bioindicadores da qualidade dos ambientes marinhos devido a peculiaridades biológicas e ecológicas desta mega-fauna. Desta forma, este trabalho objetivou propor o boto cinza como espécie sentinela da saúde dos ecossistemas costeiros ao longo de sua distribuição (desde Santa Catarina, sul do Brasil até Honduras, América Central). Além disso, este estudo objetivou a utilização desta espécie como bioindicadora da biodisponibilização de Hg total no estuário Amazônico e costa norte do Rio de Janeiro. Na primeira abordagem desta pesquisa a literatura disponível sobre impactos da contaminação e doenças emergentes sobre o boto-cinza foi revisada e discutida. Apesar de a literatura pesquisada ser incipiente se comparada com estudos realizados no hemisfério norte, estudos recentes têm revelado altos níveis de contaminantes nesta espécie (e.g. metais pesados, organoclorados, PCBs, compostos organoestânicos, PFOS e PBDE). A presença de doenças emergentes, tais como doenças cutâneas e ósseas, além da identificação de infecções causadas por organismos potencialmente patogênicos (e.g. giardíase, lobomicose, toxoplasmose e presença de Vibrio sp.) tem sido notificadas em S. guianensis. Para o estudo das concentrações de Hg total, amostras de músculo de 20 botos-cinza da costa norte do Rio de Janeiro e 29 da costa do Amapá foram analisadas. A concentração média de Hg foi 0,38 (0,07-0,79) para a costa do Amapá (AP) e 1,07 microgramas/g-1 pu (0,20-1,66) para a costa do Rio de Janeiro (RJ). Os baixos níveis de Hg para a costa do AP é provavelmente devido à ausência de fontes antrópicas deste elemento para o ambiente, entretanto, os níveis detectados para a costa do RJ estão possivelmente associados à liberação ambiental deste poluente ao longo da costa. Os níveis de ambas as áreas de estudos mostraram baixos níveis de Hg quando comparados com estudos em diversas regiões do mundo. Não houve diferença significativa de Hg para machos e fêmeas e as concentrações tenderam a se elevar com o aumento do comprimento total. Com base nos resultados desta pesquisa, propõe-se a espécie Sotalia guianensis como organismo sentinela da saúde dos ecossistemas costeiros. Além disso, esta pesquisa aponta a necessidade de estudos adicionais sobre contaminantes e a possível associação destes com as doenças emergentes e organismos patogênicos detectados nesta espécie ameaçada.