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

Organohalogen compounds in a hotspot for chemical pollution: Assessment in free-ranging Atlantic spotted dolphins (Stenella frontalis)

The assessment of chemical pollution in free-ranging living mammals is viable using remote biopsies and portrays a comprehensive scenario of environmental health. The Southwestern Atlantic Ocean holds incredible biodiversity, but it is under the constant and invisible threat of persistent organic pollutants (POPs) of anthropogenic origin, such as pesticides, brominated flame retardants, and industrial-use compounds (e.g., PCBs). Thus, this study aimed to assess the bioaccumulation of POPs (PCBs, DDTs, HCB, mirex and PBDEs) and natural organobromine compounds (MeO-BDEs) using gas-chromatography coupled to mass spectrometry in biopsy samples of Atlantic spotted dolphins (Stenella frontalis, n = 20) that inhabit and forage both inside and in adjacent areas to degraded (Guanabara Bay) and conserved (Ilha Grande Bay) coastal bays in the Southeastern Brazil. Among the studied compounds, PCBs were predominant in the contamination profile with median concentration of 97.0 μg.g-1 lipid weight (lw), followed by the sum of the p,p' isomers of DDT, DDD, and DDE of 11.0 μg.g-1 lw, the brominated flame retardants PBDEs of 1.6 μg.g-1 lw, and the other organochlorine pesticides mirex of 0.78 μg.g-1 lw, and HCB of 0.049 μg.g-1 lw. The MeO-BDEs were detected with a median concentration of 22.8 μg.g-1 lw. 85 % of the Atlantic spotted dolphins analyzed in this study presented PCB concentration that exceeded even the less conservative threshold limits for adverse health effects (41 μg.g-1 lw). This study shows that despite the conservation status of preserved bays, cetacean species foraging in these locations are still under increased threat. Hence chemical pollution demands local and global efforts to be mitigated.

Back on top: Resuspended by dredging and other environmental disturbances, organochlorine compounds may affect the health of a dolphin population in a tropical estuary, Sepetiba Bay

Organochlorine compounds (OCs) are persistent organic pollutants linked to damaging the immune and endocrine systems, leading to a greater susceptibility to infectious diseases at high concentrations. Sepetiba Bay, in the Southeastern Brazilian coast, historically presents anthropogenic activities and environmental contamination that could negatively impact resident populations. In this context, this study aimed to investigate the temporal trends in the accumulation of organochlorine compounds over a 12-year database in the Guiana dolphins' (Sotalia guianensis) resident population from Sepetiba Bay, including individuals collected before, during, and after an unusual mortality event triggered by morbillivirus (n = 85). The influence of biological parameters was also evaluated. The OCs concentrations in the blubber ranged from 0.98 to 739 μg/g of ΣPCB; 0.08-130 μg/g of ΣDDT; <0.002-4.56 μg/g of mirex; <0.002-1.84 μg/g of ΣHCH and <0.001-0.16 μg/g of HCB in lipid weight. Increased temporal trends were found for OCs in Guiana dolphins coinciding with periods of large events of dredging in the region. In this way, our findings suggest that the constant high OCs concentrations throughout the years in this Guiana dolphin population are a result of the constant environmental disturbance in the area, such as dredging. These elevated OCs levels, e.g., ΣPCB concentrations found above the known thresholds, may impair the response of the immune system during outbreak periods, which could lead the population to a progressive decline.

Brominated flame retardants and natural organobrominated compounds in a vulnerable delphinid species along the Brazilian coast

Guiana dolphins, Sotalia guianensis, are vulnerable to extinction along their distribution on the Brazilian coast and assessing chemical pollution is of utmost importance for their conservation. For this study, 51 carcasses of Guiana dolphins were sampled across the Brazilian coast to investigate legacy and emerging brominated flame retardants (BFRs) as well as the naturally-produced MeO-BDEs. PBDEs and MeO-BDEs were detected in all samples analyzed, whereas emerging BFRs were detected in 16 % of the samples, all in Rio de Janeiro state. PBDE concentrations varied between 2.24 and 799 ng.g-1 lipid weight (lw), emerging BFRs between 0.12 and 1.51 ng.g-1 lw and MeO-BDEs between 3.82 and 10,247 ng.g-1 lw. Concentrations of legacy and emerging BFRs and natural compounds varied considerably according to the sampling site and reflected both the local anthropogenic impact of the region and the diversity/mass of biosynthesizers. The PBDE concentrations are lower than what was found for delphinids in the Northern Hemisphere around the same sampling period and most sampling sites presented mean concentrations lower than the limits for endocrine disruption known to date for marine mammals of 460 ng.g-1 lw, except for sampled from Santa Catarina state, in Southern Brazil. Conversely, MeO-BDE concentrations are higher than those of the Northern Hemisphere, particularly close to the Abrolhos Bans and Royal Charlotte formation, that are hotspots for biodiversity. Despite the elevated concentrations reported for this group, there is not much information regarding the effects of such elevated concentrations for these marine mammals. The distinct patterns observed along the Brazilian coast show that organobrominated compounds can be used to identify the ecological segregation of delphinids and that conservation actions should be planned considering the local threats.

Health conditions of Guiana dolphins facing cumulative anthropogenic impacts

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.

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.

Organochlorine contaminants in Rio skate (Rioraja agassizii), an endangered batoid species, from southeastern coast of Brazil

A global movement towards decreases in elasmobranch overfishing has been noted in the last decades. However, discussion concerning the effects of POP contamination on the health and survival of these organisms is still recent. These compounds can affect the immune and endocrine systems of both sharks and batoids, impairing reproduction and impacting species recruitment, acting synergistically alongside overfishing effects. In this context, this study investigated the concentration of organochlorine compounds in liver of 29 individuals of Rioraja agassizii, a commercially exploited skate classified as Vulnerable by IUCN and as Endangered in Brazil. Contaminant concentrations were higher in adults compared to juveniles. Distinct contamination profiles were observed, suggesting different groups within the investigated population and revealing contaminants as a potential tool to assess population ecology. PCB levels were considered a concern as they resemble concentrations in ecosystems from the northern hemisphere, where deleterious effects on elasmobranchs have been observed.

Franciscana dolphins, Pontoporia blainvillei, as environmental sentinels of the world's largest mining disaster: Temporal trends for organohalogen compounds and their consequences for an endangered population

On November 5th, 2015, the Fundão dam collapsed in Minas Gerais, southeastern Brazil, releasing millions of cubic meters of mud containing mining residue into the Doce River. Two weeks later, the mud arrived to the marine environment, triggering changes in franciscana dolphin habitat, Pontoporia blainvillei, from Franciscana Management Area Ia. This is an isolated population of the most endangered cetacean species in the South Atlantic Ocean. Organohalogen compounds (OHCs) may pose a threat to this endangered population because of their endocrine disrupting properties. Hence, this study sought to determine if there were differences in the bioaccumulation profile of OHC (PCBs, DDTs, Mirex, HCB, HCHs, PBDEs, PBEB, HBBZ and MeO-BDEs) in franciscana dolphins before and after dam collapse and to build a temporal trend. Blubber of 33 stranded individuals was collected in Espírito Santo state for organohalogen assessment between 2003 and 2019. Differences were found between franciscana dolphins collected prior to and after the disaster. Additionally, significant temporal trends for organochlorine pesticides and natural and anthropogenic organobromine were detected. The increase in pesticide concentrations after 2015 is suggestive of their reavailability in the environment. The decline in organobromine over time could be due to their debromination in the marine environment and alterations in the composition of their natural producers. PCBs remained stable during the period of the study. Our findings show an increase in endocrine disruptor concentrations, which is of great concern for this endangered population.

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

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%.

Additional Pressure to a Threatened Species: High Persistent Organic Pollutant Concentrations in the Tropical Estuarine Batoid Gymnura altavela

Persistent organic pollutants (POPs) were determined in Gymnura altavela liver samples from one of the most impacted estuarine environments in the Atlantic Ocean (Guanabara Bay, Brazil). PCBs were the predominant compounds (91.2%) averaging 6773 ± 4659 ng.g^-1 lipid weight (lw). DDT, Mirex, HCH and HCB concentrations were 633 ± 715, 6.2 ± 9.3, 3.4 ± 1.4 and 0.5 ± 0.5 ng.g^-1 lw, respectively. Recent DDT input in the estuary was minimum, as verified by the p,p'-DDE/∑DDT ratio (0.67). The prevalence of industrial compounds was highlighted by the ΣDDT/ΣPCB ratio (0.08). A negative correlation detected between disc width and PCBs, Mirex and HCH concentrations may be a consequence of maternal offloading. High POP concentrations in G. altavela liver samples from Guanabara Bay suggests that PCBs, in particular, may pressure the conservation of this threatened with extinction tropical estuarine batoid species.

How protected are marine protected areas: A case study of tributyltin in Latin America

Protected areas (PAs) are dedicated and managed to achieve long-term conservation of nature with associated ecosystem services and cultural values. However, few studies have assessed contamination/pollution, one of the top five biodiversity threats, within these areas. In fact, more than 100,000 molecules used in consumer goods are potentially affecting over 250,000 protected areas distributed worldwide. As a result, chemical appraisal within PAs require specific approaches to be feasible. Herein, an approach for assessment of contamination in marine protected areas (MPAs) spread over large continental and/or global areas was proposed and tested using, as a case study, the impact of tributyltin (TBT) within Latin America. This approach included area delimitation, bibliographic survey, construction of attribute tables, data insertion in a Geographic Information System, overlapping with worldwide shapefiles of PAs, identification of affected PAs and evaluation of impacts using the outcomes against specific environmental quality guidelines/directives. A total of 259 records of TBT occurrence and/or its biological effect within 53 marine protected areas (including biosphere reserves, Ramsar sites and National parks) were gathered. Among affected species, were recorded 18 gastropods exhibiting imposex. In addition, 6 bivalves, 1 crustacean, and 3 fish species presenting TBT residues in tissues were seen in MPAs from Brazil, Argentina, Ecuador, Peru, Chile and Venezuela. Since levels of TBT recorded in several studied MPAs were enough do induce deleterious biological responses over marine biota, it was clear that conservancy goals of some "protected" areas are under threat. Considering that only TBT exposure was appraised, and these areas are likely to be concomitantly exposed to other classes of contaminants, the actual scenario can be even more frightening. Although initially applied as a TBT case study, the present approach enables an overview for other chemicals within protected areas worldwide.

Total tin (TSn) biomagnification: Evaluating organotin trophic flow and dispersion using hepatic TSn concentrations and stable isotope (C, N) data of nektonic organisms from Brazil

A previous investigation of our research team has demonstrated the suitability of using hepatic total tin (ΣSn) concentrations for evaluating dolphin exposure to organotins (OTs). The present study develops the previous technique into three different approaches that comprise data: (1) on hepatic ΣSn concentrations of 121 Guiana dolphins (Sotalia guianensis) from five different coastal areas (CAs): (2) on ΣSn, δ¹³C and δ¹⁵N for 40 dolphins from Rio de Janeiro state (RJ), including ten different delphinid species; as well as (3) on hepatic ΣSn concentrations and δ¹⁵N values on 31 individuals from five different fish species from Sepetiba Bay (SB, Rio de Janeiro-RJ, Brazil). Hepatic ΣSn concentrations of Guiana dolphins from Guanabara Bay (GB, RJ) were significantly higher than those found in other four CAs from S and SE Brazilian regions. Significant positive correlations were found between ΣSn concentrations and δ¹³C data in delphinid species, demonstrating a coast-ocean gradient in dolphin exposure to OTs in RJ state. Significant and positive correlations were observed between ΣSn concentrations and both δ¹⁵N and Trophic Position (TP) values of fish, as well as high values were found for Trophic Magnification Factor (TMF = 3.03) and Trophic Magnification Slope (TMS = 0.14), demonstrating OT biomagnification in SB ichthyofauna.

Strandings of cetaceans on the Espírito Santo coast, southeast Brazil, 1975-2015

Espírito Santo state is located on the eastern margin of Brazil, in a transitional tropical-subtropical area (18°S–21°S) dominated by oligotrophic waters. With the exception of humpback whales (Megapteranovaeangliae), the cetacean community of Espírito Santo has been understudied. In addition to the chronic impacts from fisheries, marine pollution, urban development, and coastal habitat degradation, in November 2015 the cetacean communities of Espírito Santo were challenged by the greatest environmental disaster in Brazil’s history. The Mariana dam disaster caused 60 million cubic meters of mining waste to be washed into the Doce River, which ultimately flowed to the coastal waters of Espírito Santo, with a high concentration of heavy metals. This study reviews and updates information on cetacean strandings in the state of Espírito Santo (excluding humpback whales) prior to this disaster. From 1975 to September 2015, there were 461 recorded cetacean strandings, representing 20 species. An average 1.18 strandings per 100 km per month were recorded since a state-wide daily beach survey program was implemented in October 2010, contrasting with the 0.14 strandings per 100 km per month in previous years. Six species comprised the majority (94.7%) of stranding events: Guiana dolphin (Sotaliaguianensis), Franciscana (Pontoporiablainvillei), rough-toothed dolphin (Stenobredanensis), bottlenose dolphin (Tursiopstruncatus), sperm whale (Physetermacrocephalus), and melon-headed whale (Peponocephalaelectra). Oceanic cetaceans stranded most frequently on the southern portion of Espírito Santo, where the continental platform is narrower, whereas the strandings of coastal cetaceans such as Guiana dolphins and Franciscanas were concentrated near estuaries, especially the Doce River. This is particularly concerning in face of the Mariana dam disaster, which drastically altered the estuarine and coastal environment associated with the Doce River.

Pyrethroid insecticides along the Southwestern Atlantic coast: Guiana dolphin (Sotalia guianensis) as a bioindicator

The presence of pyrethroid compounds in hepatic tissue of Guiana dolphins (Sotalia guianensis) is reported for the first time. Twelve pyrethroids were determined in 50 animals from eight locations of the Brazilian coast. The highest average concentration of total pyrethroids (∑PYR) was 1166 ng.g^-1 lw, with values ranging from 148 to 5918 ng.g^-1 lw, in Ilha Grande Bay, Rio de Janeiro State, while the Espírito Santo State had the highest median, 568 ng.g^-1 lw. Permethrin was the predominant compound in most areas, contributing for 42% to 81% of the ∑PYR, whereas cypermethrin was the most abundant compound in Guanabara and Sepetiba bays (79% and 81%, respectively), both located in Rio de Janeiro State. Biological factors were not correlated with pyrethroids concentration. Tetramethrin and es/fenvalerate compounds were negatively correlated to the age, suggesting degradation/metabolization capacity in these animals that increases throughout life. Despite being metabolized and excreted, the wide use of these pollutants is reflected in relevant concentrations found in Guiana dolphins. This is the first study evaluating pyrethroids in a representative number of hepatic samples and covering >2600 km of coast. The overall lack of information on pyrethroids in cetaceans highlights the importance of understanding the profile and distribution of these pollutants in dolphins which exclusively inhabit the Southwestern Atlantic coast.

PCBs occurrence in marine bivalves and fish from Todos os Santos Bay, Bahia, Brazil

In order to evaluate contamination by polychlorinated biphenyls (PCBs) in a tropical bay exposed to different anthropogenic pressures, samples of bivalves: mangrove oyster (Crassotrea rhizophorae), mangrove mussel (Mytella guyanensis)and clams (Anomalocardia brasiliana), were collected in different parts of Todos os Santos Bay, Bahia, Brazil. In addition, samples of bivalves and fish, purchased from a seafood market in the city of Salvador were analyzed to evaluate human exposure to PCBs through ingestion. Identification and quantification of PCBs were done by GC/MS after microwave extraction and purification with sulfuric acid. In bivalves, concentrations ranged from <0.08 to 50.1 ng g ^-1 (dry weight), with the highest values being detected in mangrove oyster, followed by clams and mangrove mussel of the Subaé estuary and Madre de Deus/Mataripe; regions known to be impacted by anthropic activities. From the total of the 12 fish species analyzed, only 5 presented levels of PCBs above the detection limit, ranging from 0.23 to 4.55 ng g ^-1 and 0.51 to 26.05 ng g ^-1 by dry weight and lipid weight, respectively. In general, concentrations of PCBs on the bay are lower than in most regions around the world, especially those located in the Northern Hemisphere. Indexes indicated that local biota and seafood from the fish market are not adversely impacted by PCBs and do not represent a risk to human health.

First evaluation of legacy persistent organic pollutant contamination status of stranded Yangtze finless porpoises along the Yangtze River Basin, China

Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis), inhabiting the Yangtze River, are an endangered species in China. They are threatened by various kinds of pollutants, among which persistent organic pollutants (POPs) are of special concern due to their toxicities, high persistency and bioaccumulation potential. To better understand the POP contamination status of Yangtze finless porpoises, an investigation of stranded porpoises along the Yangtze River and adjacent two major lakes in the Yangtze River basin was conducted; the concentrations of four groups of legacy POPs, i.e., hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyl (PCBs), were determined in the blubber samples. The mean concentrations of ΣHCHs (the sum of all congeners/isomers), ΣDDTs, ΣPBDEs and ΣPCBs, were 1670 ± 4210, 28,800 ± 52,300, 141 ± 174, and 1020 ± 1070 ng/g lipid weight, respectively; the high DDTs/PCBs ratio reflected a strong influence of agricultural pollution in the Yangtze River basin, and the high α/γ ratio of HCH isomers indicated the usage of lindane in the corresponding areas; the predominance of low-brominated congeners of PBDEs may be related to congruent patterns in the related environmental matrices. A hazard quotient risk assessment revealed that DDTs could pose a relatively high risk to Yangtze finless porpoises compared with the risks posed by the other POPs.

Clinical signs in free-ranging Guiana dolphins Sotalia guianensis during a morbillivirus epidemic: case study in Sepetiba Bay, Brazil

From November 2017 to March 2018, a cetacean morbillivirus (CeMV) outbreak caused an unprecedented mass mortality among Guiana dolphins Sotalia guianensis in Ilha Grande Bay and Sepetiba Bay, Rio de Janeiro, Brazil. Small boat surveys were conducted to document the behavior and clinical signs presented by diseased dolphins. We observed 5 abnormally behaving, disoriented Guiana dolphins on separate days, of which 1 died stranded and 2 sank. Signs of ataxia included difficulties with swimming and maintaining a course, balance and buoyancy. At least 40 other individuals were emaciated, and 10 photo-identified dolphins had miscellaneous skin lesions, some ulcerated. Labored breathing suggestive of airway obstruction was heard in several groups. These neurological, respiratory and cutaneous signs may comprise part of the clinical constellation of CeMV infection in dolphins. The combined threat of anthropogenic pressures and CeMV lethal disease is of concern for the survival of the Guiana dolphin population in Sepetiba Bay.

PCB and PBDE contamination in Tursiops truncatus and Stenella frontalis, two data-deficient threatened dolphin species from the Brazilian coast

Polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE) levels were assessed in the liver and muscle of two data-deficient threatened dolphin species, the bottlenose dolphin (Tursiops truncatus, n = 4) and the Atlantic spotted dolphin (Stenella frontalis, n = 6), sampled off the Southeastern Brazilian coast. PCB concentrations were greater in liver compared to muscle, with males presenting higher concentrations than females. The three main detected PCB congeners were PCBs 138, 153 and 180. A predominance of hexachlorinated congeners was observed, followed by hepta- and penta-PCBs. For both species, Cl 3 and Cl 4 levels were higher in muscle compared to liver, while Cl 5 to Cl 8 and ∑PCBs were higher in liver. PBDE concentrations were significantly higher in Atlantic spotted dolphin muscle and liver compared to bottlenose dolphins. Similarly to PCBs, the highest PBDE concentrations were observed in males. The presence of PBDE congeners BDE-47, -100 and -99 in the muscle and liver of both species suggests the existence of a pollution source in Brazil by a penta-BDE mixture, as PBDEs have never been produced in Brazil. Interspecific PCB and PBDE profiles were very similar, which may be related to the similar characteristics of the analyzed species, mainly geographic distribution and life and feeding habits. This study furthers knowledge on environmental PCB and PBDE contamination, assisting in the establishment of dolphin population conservation strategies. In addition, this study calls into question the current threshold values established for PCBs and PBDEs, and demonstrates the lack of information and knowledge in this regard for cetaceans.

Inter-individual differences in contamination profiles as tracer of social group association in stranded sperm whales

Ecological and physiological factors lead to different contamination patterns in individual marine mammals. The objective of the present study was to assess whether variations in contamination profiles are indicative of social structures of young male sperm whales as they might reflect a variation in feeding preferences and/or in utilized feeding grounds. We used a total of 61 variables associated with organic compounds and trace element concentrations measured in muscle, liver, kidney and blubber gained from 24 sperm whales that stranded in the North Sea in January and February 2016. Combining contaminant and genetic data, there is evidence for at least two cohorts with different origin among these stranded sperm whales; one from the Canary Island region and one from the northern part of the Atlantic. While genetic data unravel relatedness and kinship, contamination data integrate over areas, where animals occured during their lifetime. Especially in long-lived animals with a large migratory potential, as sperm whales, contamination data may carry highly relevant information about aggregation through time and space.

Occurrence of organic UV filters and metabolites in lebranche mullet (Mugil liza) from Brazil

UV filters (UV-Fs) constitute a heterogeneous group of chemicals used as protection against the effects of UV radiation, widely used in all sort of goods and ubiquitous in the environment. The presence of these chemicals in fish is a matter of concern, because many UV-Fs display hormonal activity. In this study, muscle, gills, and liver from 11 Mugil liza individuals from the highly urbanized Guanabara Bay (Rio de Janeiro, Brazil) were analysed in order to detect eight UV-Fs and metabolites (4-dihydroxybenzophenone [BP1] (2-hydroxy-4-methoxybenzophenone [BP3], 4-methylbenzylidiene camphor [4MBC], ethylhexyl methoxycinnamate [EHMC], ethylhexyl dimethyl p-aminobenzoic acid [ODPABA], octocrylene [OC], 4-hydroxybenzophenone [4HB], and 4,4'-dihydroxybenzophenone [4DHB]) using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results showed that both target UV-Fs and metabolites were ubiquitous in the analysed tissues. Lower concentrations were observed in muscle and gills (3.07-31.6ngg^-1 dry weight (dw)), whereas in liver significant amounts of metabolites (5.47-451ngg^-1 dw) were present. With the concentrations determined in the fish, an estimation of the daily intake revealed that consumption of muscle in the diet represent from 0.3 to 15.2ng UV-Fs (kg body weight^-1) d^-1, higher than those reported in fish for selected persistent organic pollutants (POPs).

Nontargeted Screening of Halogenated Organic Compounds in Bottlenose Dolphins (Tursiops truncatus) from Rio de Janeiro, Brazil

To catalog the diversity and abundance of halogenated organic compounds (HOCs) accumulating in high trophic marine species from the southwestern Atlantic Ocean, tissue from bottlenose dolphins (Tursiops truncatus) stranded or incidentally captured along the coast of Rio de Janeiro, Brazil, were analyzed by a nontargeted approach based on GC×GC/TOF-MS. A total of 158 individual HOCs from 32 different structural classes were detected in the blubber of 4 adult male T. truncatus. Nearly 90% of the detected compounds are not routinely monitored in the environment. DDT-related and mirex/dechlorane-related compounds were the most abundant classes of anthropogenic origin. Methoxy-brominated diphenyl ethers (MeO-BDEs) and chlorinated methyl- and dimethyl bipyrroles (MBPs and DMBPs) were the most abundant natural products. Reported for the first time in southwestern Atlantic cetaceans and in contrast to North American marine mammals, chlorinated MBPs and DMBPs were more abundant than their brominated and/or mixed halogenated counterparts. HOC profiles in coastal T. truncatus from Brazil and California revealed a distinct difference, with a higher abundance of MeO-BDEs, mirex/dechloranes and chlorinated bipyrroles in the Brazilian dolphins. Thirty-six percent of the detected HOCs had an unknown structure. These results suggest broad geographical differences in the patterns of bioaccumulative chemicals found in the marine environment and indicate the need to develop more complete catalogs of HOCs from various marine environments.

POPs in the South Latin America: Bioaccumulation of DDT, PCB, HCB, HCH and Mirex in blubber of common dolphin (Delphinus delphis) and Fraser's dolphin (Lagenodelphis hosei) from Argentina

Organic compounds, in particular organochlorines, are highly persistent compounds which accumulate in biotic and abiotic substrates. Marine mammals bioaccumulate and biomagnify persistent organic pollutants (POPs) through diet. ∑PCB (26 PCB congeners), ∑DDT (pp-DDT, pp-DDD, pp-DDE), ∑HCH (α-HCH, β-HCH, γ-HCH, δ-HCH), HCB and mirex were analyzed from samples of subcutaneous adipose tissue of common dolphins, Delphinus delphis, and Fraser's dolphins, Lagenodelphis hosei, obtained in 1999 and 2012. The aim of this study was to determine the concentrations of POPs to get baseline information on the current state of pollution by these compounds in these two species in South Atlantic. At the same time, to assess concentrations of POPs in relation to age, the total length and sexual maturity in common dolphins. Organochlorine pesticides dominated Fraser's dolphins, DDT being the most abundant, while PCBs were mostly present in common dolphins. In both species, the distributions of isomers or metabolites followed the order: β-HCH>δ-HCH>γ-HCH>α-HCH and pp-DDE>pp-DDD>pp-DDT. As for ∑PCB, the largest contribution was given by congeners of high molecular weight, particularly by hexa and hepta - CBs. Common dolphins did not show effects on sexual maturity, age and standard length in the concentration of organochlorines. The mean concentrations found in this study are lower compared to those reported in other studies performed in dolphins elsewhere. This study provides new information regarding levels of organochlorines in common dolphins for the Southwestern Atlantic.

Variation of age and total length in Sotalia guianensis (Van Bénéden, 1864) (Cetacea, Delphinidae), on the coast of Espírito Santo state, Brazil

Variations of age and total length of Sotalia guianensis from the state of Espírito Santo, Brazil, were evaluated. Specimens were found stranded. Age and total length of 44 Guiana dolphins were assessed based on tooth analysis. Age varied between 0.5 year and 33 years (mean = 8.23 years). Most specimens were between zero and 6 years old (47%). Total length varied from 119 cm to 198 cm, with mean of 172.52 cm. Asymptotic length was reached at 185 cm and approximately 5-6 years of age. Mean total length and age were higher than in other regions of the distribution range of the species. Nevertheless, more studies have to be carried out to evaluate the morphological variations in S. guianensis populations in the study area and Brazil.

Guiana Dolphins (Sotalia guianensis) and DR-CALUX for Screening Coastal Brazilian Environments for Dioxins and Related Compounds

Guiana dolphin is the top predator of highest toxicological concern in Brazil and many studies on levels of persistent, bioaccumulative, and toxicant (PBT) pollutants have been performed on the species. However, due to high costs of the analyses, only one investigation comprised the determination of dioxins and related compounds (DRCs) in Guiana dolphin tissues. The dioxin responsive-chemically activated luciferase gene expression (DR-CALUX(®)) cell bioassay was used in the present study for the analyses of hepatic samples from 28 male Guiana dolphins in order to screen estuarine environments for DRCs, comprising three regions (Northeastern, Southeastern, and Southern) and four states [Paraná (PR), Rio de Janeiro (RJ), Espírito Santo (ES), and Ceará (CE)] of Brazil. High bioanalytical equivalent (BEQ) concentrations [dioxins (pg BEQ/g lipid)] were found, varying from 1.94 to 15.6 pg BEQ/g. A significant negative correlation between BEQ concentrations and total length was found in Guiana dolphins from Brazil (all analysed dolphins). This pattern also was verified for RJ state, pointing to (1) chemically induced developmental disruption or to (2) increasing efficiency of the detoxifying activity with the growth of the animal. Comparison was performed with literature data and significantly higher BEQ levels were found in Brazilian Guiana dolphins than in those reported for North Sea harbour porpoises. Higher levels were found in Southeastern (the most PBT-contaminated area of the country) than in Southern region. However, it is not possible to affirm that Guiana dolphins are more contaminated by DRCs in SE than in S region, because individuals were lengthier in S than in SE region. Our results seem to have mirrored dolphin exposure to PCBs in Brazil according to the literature. Further studies are required for investigating the hypotheses 1 and 2 mentioned above.

PCB and PBDE levels in a highly threatened dolphin species from the Southeastern Brazilian coast

In the Northern coast of Rio de Janeiro State is located the major urban centers of the oil and gas industry of Brazil. The intense urbanization in recent decades caused an increase in human use of the coastal areas, which is constantly impacted by agricultural, industrial and wastewater discharges. Franciscana dolphin (Pontoporia blainvillei) is a small cetacean that inhabits coastal regions down to a 30 m depth. This species is considered the most threatened cetacean in the Western South Atlantic Ocean. This study investigated the levels of 52 PCB congeners and 9 PBDE congeners in liver of nine individuals found stranded or accidentally caught between 2011 and 2012 in the Northern coast of Rio de Janeiro. PCB mean levels ranged from 208 to 5543 ng g(-1) lw and PBDEs mean concentrations varied between 13.84 and 36.94 ng g(-1) lw. Contamination patterns suggest the previous use of Aroclor 1254, 1260 and penta-BDE mixtures in Brazil. While still few studies have assessed the organic contamination in cetaceans from the Southern Hemisphere, including Brazil, the levels found in this study could represent a health risk to these endangered species.

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.

Toxic heritage: Maternal transfer of pyrethroid insecticides and sunscreen agents in dolphins from Brazil

Pyrethroids (PYR) and UV filters (UVF) were investigated in tissues of paired mother-fetus dolphins from Brazilian coast in order to investigate the possibility of maternal transfer of these emerging contaminants. Comparison of PYR and UVF concentrations in maternal and fetal blubber revealed Franciscana transferred efficiently both contaminants to fetuses (F/M > 1) and Guiana dolphin transferred efficiently PYR to fetuses (F/M > 1) different than UVF (F/M < 1). PYR and UVF concentrations in fetuses were the highest-ever reported in biota (up to 6640 and 11,530 ng/g lw, respectively). Muscle was the organ with the highest PYR and UVF concentrations (p < 0.001), suggesting that these two classes of emerging contaminants may have more affinity for proteins than for lipids. The high PYR and UVF concentrations found in fetuses demonstrate these compounds are efficiently transferred through placenta. This study is the first to report maternal transfer of pyrethroids and UV filters in marine mammals.

Levels and profiles of chlorinated and brominated contaminants in Southern Hemisphere humpback whales, Megaptera novaeangliae

The study documents the levels and profiles of selected contaminants [polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO-PBDEs)] in blubber biopsy samples collected from humpback whales (Megaptera novaeangliae) in Antarctic Peninsula waters. In addition, we investigated year-to-year and sex-related differences in the bioaccumulation patterns. Except for hexachlorobenzene (HCB), whose concentrations were in the same range as those found in whales from the Northern Hemisphere, levels of all other compounds were lower in Southern Hemisphere whales compared to literature data on animals from the Arctic and subarctic region. The mean contribution to the sum of all anthropogenic organohalogen compounds (ΣOHC) decreased in the following order ΣPCBs (44%)>HCB (31%)>ΣDDXs (13%)>ΣCHLs (4.6%)>ΣHCHs (4.4%)>ΣPBDEs (0.9%). The predominant compounds within each chemical class were: PCBs 153, 149, 101 and 138; p,p'-DDE; γ-HCH; trans-nonachlor; PBDEs 99 and 47. The most dominant MeO-PBDE congener was 6-MeO-BDE 47. As samples were collected during three consecutive summer seasons, year-to-year trends could be assessed indicating a significant decrease from 2000 to 2003 for ΣCHL levels. Higher ΣPBDE concentrations and higher values of the ΣPBDE / ΣMeO-PBDE ratio, as well as higher ratios between the two MeO-BDEs (2'-MeO-BDE 68/6-MeO-BDE 47) were found in females compared to males. Higher ΣMeO-PBDE concentrations and higher values of the ratios between the lower chlorinated and the higher chlorinated PCBs were found in males than in females. In addition, five out of six significant differences found through discriminant function analysis were gender-related. The literature reports both feeding in mid- to low-latitudes and sex-related differences in migration patterns for humpback whales from the Southern Hemisphere, indicating that the hypothesis of dietary differences between males and females cannot be excluded. Nevertheless, additional studies are required for further investigation of this hypothesis.

The relationship between land use and emerging and legacy contaminants in an Apex predator, the bottlenose dolphin (Tursiops truncatus), from two adjacent estuarine watersheds

BACKGROUND

Persistent organohalogen contaminant (POC) exposure is of concern in marine mammals due to the potential for adverse health effects. Studies have examined POCs in marine mammals on a regional scale; however, limited data exists on POC concentrations relative to land use and watersheds.

OBJECTIVE

Examine geographical variation of POC concentrations in bottlenose dolphins as it relates to land, and watershed, use.

METHODS

POC (PCBs, DDTs, and PBDEs) concentrations were measured in blubber of bottlenose dolphins (n= 40) sampled in estuarine waters near Charleston, SC. Photo-identification sighting histories were used to assess the dolphins' use of estuarine waters in two adjacent watersheds (Cooper Subbasin and Stono Subbasin) in the study area and to determine land use (developed, forested, agriculture, and wetland) associations.

RESULTS

Dolphins with ≥ 75% of their sightings in the Cooper Subbasin, which is characterized by a higher degree of developed land use, exhibited higher levels of PCBs, PBDEs, and total pesticides than those with ≥ 75% of their sightings in the Stono Subbasin. Observed differences were significant for ΣPBDEs and ΣDDTs/ΣPCBs ratio. Significant positive correlations were observed between ΣPBDEs and developed land use and between ΣDDTs/ΣPCBs and wetland land use. A significant negative correlation was observed between ΣDDTs/ΣPCBs and developed land use.

CONCLUSION

The spatial pattern of PBDEs and the ΣDDTs/ΣPCBs detected in dolphin blubber was shown to vary significantly with adjacent watersheds and land use associations.

Partition of organochlorine concentrations among suspended solids, sediments and brown mussel Perna perna, in tropical bays

For evaluating the brown mussel Perna perna as a sentinel organism regarding environmental concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the present study reports original data on the relationship between the concentrations of these chemicals in bottom surface sediments, suspended solids (SS) and concentrations bioaccumulated by this bivalve. Three P. perna cultivation areas, located at three bays in southeastern Brazil were used in this study. The three estuaries are under different degrees of environmental impact. Variations in the OCP and PCB concentrations bioaccumulated by the bivalves tended to be similar to those observed in the sediment, but differed from those found in SS. This latter difference might suggest that the SS trapping apparatuses should have been left in place for approximately 60 days (not only 15 days). This longer period would allow the integration of the environmental variability of the OCP and PCB burden adsorbed to this compartment. Authors encourage future studies to evaluate P. perna exposure to OCPs and PCBs through the evaluation of sediment concentrations.

Organochlorine concentrations (PCBs, DDTs, HCHs, HCB and MIREX) in delphinids stranded at the northeastern Brazil

Organochlorine compounds are highly persistent in the environment, causing bioaccumulation and biomagnification through the marine food chain. To verify the bioaccumulation pattern of DDT and its metabolites, as well as PCBs, Mirex, HCHs and HCB, samples of subcutaneous adipose tissue from 25 Guiana dolphins (Sotalia guianensis), two Fraser's dolphins (Lagenodelphis hosei), two spinner dolphins (Stenella longirostris), one spotted dolphin (Stenella frontalis), and one striped dolphin (Stenella coeruleoalba) were analyzed. The collected specimens were found stranded in northeastern Brazil between 2005 and 2011. The concentrations were reported in μg·g(-1) lip, varying from 0.02 to 17.3 for ΣPCB, from 0.003 to 5.19 for ΣDDT, from 0.005 to 0.16 for ΣHCH, from 0.002 to 0.16 for HCB, and from 0.02 to 2.38 for Mirex. The PCBs dominated the bioaccumulation pattern for both the Guiana and spinner dolphins; for the other species, DDT was the major compound. A discriminant function analysis revealed the differences in the organochlorine accumulation patterns between the Guiana dolphin (S. guianensis) and the continental shelf/oceanic dolphins (S. frontalis and S. longirostris). The results also show that the concentrations of organochlorine compounds found in the delphinids in northeastern Brazil were lower than the delphinids found in other regions of Brazil, as well as other locations worldwide with intense agroindustrial development and/or a larger population.

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.

Polychlorinated biphenyl (PCB) congener concentrations in aquatic birds. Case study: Ilha Grande Bay, Rio de Janeiro, Brazil

Livers from 108 birds found prostrate or dead in Ilha Grande Bay between 2005 and 2010 were analyzed for 16 PCB congeners (IUPAC numbers 8, 18, 28, 31, 52, 77, 101, 118, 126, 128, 138, 149, 153, 169, 170, and 180). The species analyzed were Egretta caerulea (Linnaeus 1758), Nycticorax nycticorax (Linnaeus 1758), Egretta thula (Molina 1782), and Ardea cocoi (Linnaeus 1766). The analysis were performed using Origin software (7.5, 2004) with a significant level of p<0.05. Data were checked for adherence to the standard assumptions of parametric tests using the Kolmogorov-Smirnov test for normality and the Levene's test for homogeneity of variances. This has revealed differences in concentration for some congeners. Results indicate relatively low PCBs contamination in aquatic birds, but it is implied the close relationship of environmental contamination, showing potential power of widespread biological and mutagenic adverse effects in trophic levels, and therefore, signalling risk to human health.

Use of carbon and nitrogen stable isotopes to study the feeding ecology of small coastal cetacean populations in southern Brazil

Samples from individuals of the populations of Sotalia guianensis (Guiana) and Pontoporia blainvillei (Franciscana) dolphins living in the Babitonga Bay estuary (26° 28′ S/48° 50′ W), and samples from individuals of a second population of P. blainvillei from a nearshore area (26° 38′ S/48° 41′ W), were collected and analyzed along with their prey between 2000 and 2006, to determine the carbon and nitrogen stable isotope ratios and to verify differences in their feeding ecology. No differences were found in the median ð15N values of Guiana (15.2‰) and Franciscana (15.9‰) dolphins living in Babitonga Bay, nor of nearshore Franciscana (15.0‰) individuals, suggesting no variation in the trophic level of these populations. However, the lack of more information on the isotopic compositions of their putative prey in the nearshore areas prevents the ability to draw definitive conclusions on this issue. The estuarine Franciscana and Guiana dolphin populations presented mean ð13C values of approximately −15.7‰, which were not statistically different from nearshore Franciscana individuals (−14.8‰). Based on stomach content analyses of these species from a previous study, it was reported that there was little overlap in the diet of estuarine Franciscanas and Guiana dolphins. However, based on the similarity of the ð13C values between these two species and of their putative prey, it appears that in fact there is an overlap in the diet of these two species. Based solely on stable isotope analysis, it was not possible to differentiate between estuarine and nearshore Franciscana populations, making it difficult to conclude whether captured nearshore specimens were indeed yearlong residents of these areas. Finally, this study suggests that Franciscana and Guiana dolphin populations are sharing the same resources, mostly L. brevis, D. rhombeus, and S. rastrifer. Therefore, the combination of resource sharing and commercial exploitation of their prey makes these two cetacean species vulnerable.

High accumulation of PCDD, PCDF, and PCB congeners in marine mammals from Brazil: a serious PCB problem

Blubber samples from three delphinid species (false killer whale, Guiana and rough-toothed dolphin), as well as liver samples from franciscana dolphins were analyzed for dioxins and related compounds (DRCs). Samples were collected from 35 cetaceans stranded or incidentally captured in a highly industrialized and urbanized area (Southeast and Southern Brazilian regions). Dioxin-like PCBs accounted for over 83% of the total TEQ for all cetaceans. Non-ortho coplanar PCBs, for franciscanas (82%), and mono-ortho PCBs (up to 80%), for delphinids, constituted the groups of highest contribution to total TEQ. Regarding franciscana dolphins, significant negative correlations were found between total length (TL) and three variables, ΣTEQ-DRCs, ΣTEQ-PCDF and ΣTEQ non-ortho PCB. An increasing efficiency of the detoxifying activity with the growth of the animal may be a plausible explanation for these findings. This hypothesis is reinforced by the significant negative correlation found between TL and PCB126/PCB169 concentration ratio. DRC concentrations (ng/g lipids) varied from 36 to 3006, for franciscana dolphins, as well as from 356 to 30,776, for delphinids. The sum of dioxin-like and indicator PCBs varied from 34,662 to 279,407 ng/g lipids, for Guiana dolphins from Rio de Janeiro state, which are among the highest PCB concentrations ever reported for cetaceans. The high concentrations found in our study raise concern not only on the conservation of Brazilian coastal cetaceans, but also on the possibility of human health problem due to consumption of fish from Brazilian estuaries.

Polybrominated diphenyl ethers (PBDES) and polychlorinated biphenyls (PCBS) in mussels and two fish species from the estuary of the Guanabara Bay, Southeastern Brazil

The present investigation aimed to analyze PBDE and PCB contamination in mussels (Perna perna) and two commercially important fish species, croaker (Micropogonias furnieri) and mullet (Mugil liza), in the Guanabara Bay, the most important Brazilian estuary, by gas chromatography coupled to mass spectrometry, in order to further knowledge regarding these compounds in the southern hemisphere. This is also the first report of PBDE in this mussel species in the Guanabara Bay. Fish were captured in September (dry season, winter) and March (wet season, summer) 2007 and September 2008. Mussels were collected in August (dry season, winter) 2006, in February (wet season, summer) 2007, and in August 2007 (winter). The results show that all samples showed higher PCB contamination when compared to other ecosystems around the world. On the other hand, PBDEs presented lower concentrations in 41 % of the samples. Croakers presented the highest PCB and PBDE levels, with mullet showing intermediary values and mussels, the lowest.

Bulk atmospheric deposition of persistent toxic substances (PTS) along environmental gradients in Brazil

Bulk atmospheric deposition measurements for selected persistent toxic substances (PTS) were performed along environment gradients (urban-suburban-rural-background sites) in Brazil. The aim with this work is to investigate the fate of PTS and their emissions in South America, particularly along environment transects. Bulk sampler systems (polyurethane foams, 1 × 1 m(2)) were fixed along environment gradients (urban-suburban-rural-background) over summer and winter periods (2005-2007) at sites of different climate zones of Brazil. Organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) were analyzed by gas chromatography coupled to electron capture detector (Shimadzu 2010, 20i GC-ECD). Urban sites reported the highest deposition rates for all PTS, ranging from tens to thousands of pictograms per square meter per day. Basically, there were no obvious seasonal differences in deposition rate concentrations for PTS along the urban-suburban-rural-background gradient. Dichlorodiphenyltrichloroethane (DDT) and its metabolites were the OCs most frequently detected at relatively high deposition rate levels (>1,000 pg m(-2) day(-1)). Other legacy and current-use pesticides such as hexachlorocyclohexanes, endosulfans, hexachlorcyclobenzine, dieldrin, aldrin, metoxichlor, and chlodanes were also detected at lower deposition rate levels (10-100 pg m(-2) day(-1)). PCBs were detected at extremely high deposition rate levels (1,000-10,000 pg m(-2) day(-1)) with highest contributions from the tetra-PCBs (PCB-52, PCB-44, PCB-66, PCB-81, and PCB-77) and penta-PCB congeners (PCB-101, PCB-105, PCB-114, PCB-118, and PCB-126). The greatest deposition rate concentrations for total PCBs were mainly detected at urban sites in connection with high population densities. The observed high deposition rate concentrations for PCBs and DDTs at urban sites are probably associated with old PTS stocks emissions. For PCBs in particular, the high levels are strongly associated with local population densities, highlighting the effect of local/regional urban sources on these target PTS. These results are important to show that even though the use of PTS is regulated, the deposition of selected PTS is still impacted by local and regional emissions in Brazil and may be related to the historical and continued emissions from old PTS stocks.

Occurrence, bioavailability and toxic effects of trace metals and organic contaminants in mangrove ecosystems: a review

Although their ecological and socioeconomic importance has received recent attention, mangrove ecosystems are one of the most threatened tropical environments. Besides direct clearance, hydrological alterations, climatic changes or insect infestations, chemical pollution could be a significant contributor of mangrove degradation. The present paper reviews the current knowledge on the occurrence, bioavailability and toxic effects of trace contaminants in mangrove ecosystems. The literature confirmed that trace metals, Polycyclic Aromatic Hydrocarbons (PAHs), Persistent Organic Pollutants (POPs), Pharmaceuticals and Personal Care Products (PPCPs) and Endocrine Disrupters Compounds (EDCs) have been detected in various mangrove compartments (water, sediments and biota). In some cases, these chemicals have associated toxic effects on mangrove ecosystem species, with potential impact on populations and biodiversity in the field. However, nearly all studies about the bioavailability and toxic effects of contaminants in mangrove ecosystems focus on selected trace metals, PAHs or some "conventional" POPs, and virtually no data exist for other contaminant groups. The specificities of mangrove ecosystems (e.g. biology, physico-chemistry and hydrology) support the need for specific ecotoxicological tools. This review highlights the major data and methodological gaps which should be addressed to refine the risk assessment of trace pollutants in mangrove ecosystems.

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

Liver samples from 53 Franciscana dolphins along the Brazilian coast were analyzed for organobrominated compounds. Target substances included the following anthropogenic pollutants: polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), pentabromoethylbenzene (PBEB), hexabromobenzene (HBB), decabromodiphenylethane (DBDPE), as well as the naturally-generated methoxylated-PBDEs (MeO-PBDEs). PBDE concentrations ranged from 6 to 1797 ng/g lw (mean 166 ± 298 ng/g lw) and were similar to those observed in cetaceans from Northern Hemisphere. PBBs were found in all sampling locations (<LOQ to 57 ng/g lw). DBDPE was detected in 42% of the dolphins from the most industrialized Brazilian state and the concentrations ranging from <LOQ to 352 ng/g lw. Franciscana dolphins from the tropical Brazilian shore presented the highest MeO-PBDE concentrations ever reported for coastal cetaceans (up to 14 μg/g lw). Eight MeO-PBDE congeners were detected and the present investigation constituted the first record of occurrence of six of them in marine mammal livers.

Organochlorine compound accumulation in delphinids from Rio de Janeiro State, southeastern Brazilian coast

The present study investigated organochlorine compound levels (PCBs, DDTs and HCB) in blubber samples of six delphinid species from Rio de Janeiro State, southeastern Brazilian coast. The species analyzed inhabit the continental shelf (one killer whale, one false killer whale, two bottlenose dolphins, three rough-toothed dolphins, and four long-beaked common dolphins) and open ocean (four Fraser's dolphins). PCBs represented the greatest proportion of the sum of all measured organochlorines (from 0.60 to 257.2 μg g(-1) lw), followed by DDTs (from 0.15 to 125.6 μg g(-1) lw), and, at last, HCB (from <DL to 2.91 μg g(-1) lw). Higher concentrations were found in species that occupy the inner continental shelf (rough-toothed dolphin), as well as in cetaceans that are known to or are suspected to prey on other marine mammals (killer whale and false killer whale, respectively). The findings have shown that organochlorine levels in delphinids from southeastern Brazilian coast are comparable to those reported in cetaceans from highly industrialized regions of the Northern Hemisphere. Organochlorine accumulation patterns among delphinids from Rio de Janeiro State were related to habitat use.

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.

Evaluation of the possible adverse effects of legacy persistent organic pollutants (POPs) on the brown booby (Sula leucogaster) along the Brazilian coast

This study aimed to investigate the impact of contamination by persistent organic pollutants (POPs) on Brazilian wildlife. The concentrations of certain POPs, including dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs), in the eggs of the brown booby (Sula leucogaster) were measured. The eggs were collected from breeding colonies located on three archipelagos (Saint Peter and Saint Paul, Abrolhos and Cagarras Islands) in the Atlantic Ocean, which are located at different distances from the Brazilian coast (range 4-1010 km). In addition, possible alterations in eggshell characteristics were evaluated. The average values of POPs found in eggs from the archipelago of Saint Peter and Saint Paul (0.05μgg(-1) of ΣPCBs and 0.01 μg g(-1) of ΣDDT) and the archipelago of Abrolhos (0.19 μg g(-1) of ΣPCBs and 0.03 μg g(-1) of ΣDDT) were low compared to the reference values reported in the literature. In contrast, the concentrations measured in eggs from Cagarras (8.4 μg g(-1) of ΣPCBs and 1.8 μg g(-1) of ΣDDT) were the highest, and this total PCB level is close to the threshold values considered to be harmful to birds. Our findings indicate that the brown booby colony closest to the Rio de Janeiro coast has recently been exposed to DDT. Despite the high pollution levels found on the Cagarras Islands, no alterations in the eggshell weight or the thickness of the analyzed eggs were detected. Hence, more detailed studies are recommended to determine the actual effects of the selected POPs on the Cagarras breeding colony.

Contamination by chlorinated pesticides, PCBs and PBDEs in Atlantic spotted dolphin (Stenella frontalis) in western South Atlantic

Chlorinated pesticides, PCBs and PBDEs were analysed in nine blubber samples of Atlantic spotted dolphins, Stenella frontalis, incidentally captured during fishing operations in southern and southeastern Brazil between 2005 and 2007. The majority of compounds analysed were detected, suggesting widespread contamination over the region. Although the samples came from a location far from main coastal industrial areas, the results revealed an influence from such sources. Therefore, levels of PCBs (774-23659 ng g(-1) lipid wt.) and PBDEs (23-1326 ng g(-1) lipid wt.) detected seem to be related to the movement of individuals throughout near-shore and offshore waters. The sample from a lactating female exhibited a lower level of contamination and a distinct pattern, indicating selective transfer favouring less lipophilic compounds.

Organochlorine concentrations in franciscana dolphins, Pontoporia blainvillei, from Brazilian waters

Blubber samples were collected from ten franciscana dolphins either incidentally captured in fishing operations or stranded on São Paulo (SP) and Paraná (PR) states littoral, Southeastern and Southern Brazilian coast, respectively. Determination of PCB, DDT and HCB concentrations were performed by capillary gas chromatograph coupled to electron capture detector (ECD). ΣDDT, ΣPCB and HCB concentrations ranged from 264 ng g(-1) to 5811 ng g(-1) lipid, from 909 ng g(-1) to 5849 ng g(-1) lipid and from 10 ng g(-1) to 61 ng g(-1) lipid, respectively. Regarding DDTs, the distribution of the mean percentages decreased in the following order: p,p'-DDE>p,p'-DDD>p,p'-DDT. The ΣDDT/ΣPCB ratio varied between 0.27 and 0.42 in Northern and Central SP coast, while in Southern SP and PR coast the values were 1.6 and 1.9, respectively. Dissimilarities in ΣDDT/ΣPCB ratios point to different sources of organochlorine compounds to franciscana dolphins in the study area. Considering the endocrine disruptive action of organochlorine compounds, the concentrations found in franciscana dolphins from Brazilian waters may represent an additional obstacle to the conservation of this endangered cetacean species.