From Past Use to Present Effects: Total Mercury in Crustaceans and Fish in the Inner Estuary of Paraíba do Sul River, Southeast Brazil.

Total mercury (Hg) concentration and stable isotope ratios (δ13C and δ15N) were used as chemical tracers in two crustaceans and four fish species that are targets of subsistence fishery in the inner estuary of the Paraíba do Sul River. This fluvial environment in southeast Brazil has a large historical utilization of Hg. δ15N was a better predictor of Hg concentration in the muscle (edible part) than δ13C; i.e., the Hg concentration was more closely related to the trophic position of species than species' trophic habitat. Consumers at higher trophic levels had higher Hg concentrations. The Hg concentration was below the maximum permissible limits established by the Brazilian Government in fishery products, and there are no human risks related to its consumption.

Mn2+ concentrations in coastal fish otoliths: understanding environmental and biological influences from EPR.

The Mn2+ concentrations in the sagittae otoliths of 12 fish families (and 19 species) that co-occur in a coastal area of southeastern Brazil (~21°S) were quantified using electron paramagnetic resonance (EPR). Inferences were made about the relationship between fish habitat and trace element incorporation. Inferences were made on the relationship between trace element concentration and otolith shape. The differences in Mn2+ concentrations among the species suggest that habitat (and feeding habits) might drive the incorporation of this trace element into fish otoliths, with higher values in bottom-associated fish species than in surface-associated species. In surface-associated fish species, the correlation between trace element concentrations and otolith shape was stronger than in bottom-associated species. Thus, while the Mn bioavailability in a fish's habitat, especially from feeding resources, is a local driving influence of trace element incorporation in sagittae otoliths, species-specific requirements also have an influence. Quantitative EPR is a non-destructive technique that is very useful when the available samples cannot be damaged, like with otolith collections.

Elemental Concentrations in the Shells of the Mussel Perna perna: Discrimination of Origin.

The potential use of elemental concentrations and element:calcium (Ca) ratios as indicators of provenance for bivalve mollusks on the Brazilian coast is evaluated herein for the first time. The approach was applied to shells of the mussel Perna perna (target of extractive fisheries) from geographically close areas but under distinct environmental and anthropogenic influences. Both concentrations of the elements normalized by Ca and the total concentrations can be applied to discriminate the mussels' origin. However, the canonical approach using the total concentrations indicated variations regarding the discriminatory power, and the concentrations of the elements normalized by Ca were more robust in differentiating the provenance of the shells. The origin of mussels was better discriminated by six elementary ratios: Al:Ca, Fe:Ca, K:Ca, Mg:Ca, Mn:Ca and Na:Ca. Thus, monitoring studies aiming to discriminate the origin of P. perna individuals along their distribution based on these elementary ratios of the shell are recommended.

Selenium and mercury in widely consumed seafood from South Atlantic Ocean.

The growing ingestion of predatory fish by humans has increased their exposure to toxic chemicals. Mercury (Hg) is an exogenous and harmful trace-element that accumulates in all marine organisms. Selenium (Se) is nutritionally important as a micronutrient, but is potentially harmful at intakes above 1mg per day. Se:Hg molar ratios in excess of 1:1 are thought to counteract the adverse effects of Hg, protecting against Hg toxicity. Evaluation of the health risk posed by Hg exposure from seafood consumption requires concurrent consideration of Se content in the same individuals. This study evaluated the Se and Hg concentrations in the edible tissues of 652 individual samples of commonly consumed varieties of carnivorous and planktivorous fish, squid, mussel, shrimp and crab collected from south-eastern Brazil. The Se:Hg molar ratios showed significant variation among and within tropical seafood. All organisms presented Se concentration in muscle of less than 2.0µgg(-1), the maximum allowed selenium concentrations. Only seven individuals of a carnivorous fish species presented Hg in muscle above the maximum permissible limit of 0.5µgg(-1) established by WHO and Brazilian legislation for human consumption of most aquatic species. These same individuals also showed Se:Hg molar ratio of less than 1:1. Se:Hg molar ratios were found to decline with increasing fish length, potentially reducing Se-dependent protection. As a result of their rich Se, low Hg contents and Se:Hg molar ratios exceeding 1:1, nearly all species included in this study provide benefits for human consumption. Two popular seafoods in the region, the carnivorous fish Centropomus undecimalis (common snook) and Micropogonias furnieri (Atlantic croaker), had the most favorable Se:Hg molar ratio values of 33 and 21, respectively. Among the invertebrates, Xiphopenaeus kroyeri (seabob shrimp) and Loligo sanpaulensis (squid) had the most favorable Se:Hg molar ratio values, higher than 20. A selenium health benefit value based on the absolute amounts and relative proportions of Se and Hg in seafood was proposed as a more comprehensive seafood safety criterion.

Mercury and nitrogen isotope in a marine species from a tropical coastal food web.

The present study raised the hypothesis that the trophic status in a tropical coastal food web from southeastern Brazil can be measured by the relation between total mercury (THg) and nitrogen isotope (δ(15)N) in their components. The analysed species were grouped into six trophic positions: primary producer (phytoplankton), primary consumer (zooplankton), consumer 1 (omnivore shrimp), consumer 2 (pelagic carnivores represented by squid and fish species), consumer 3 (demersal carnivores represented by fish species) and consumer 4 (pelagic-demersal top carnivore represented by the fish Trichiurus lepturus). The values of THg, δ(15)N, and trophic level (TLv) increased significantly from primary producer toward top carnivore. Our data regarding trophic magnification (6.84) and biomagnification powers (0.25 for δ(15)N and 0.83 for TLv) indicated that Hg biomagnification throughout trophic positions is high in this tropical food web, which could be primarily related to the quality of the local water.

Risk of exposure to Hg and pesticides residues in a traditional fishing community in the Amazon: a probabilistic approach based on dietary pattern.

Exposure to mercury (Hg) and pesticides (o.p'DDT, p.p'DDT, o.p'DDE, and p.p'DDE) in the Amazon through eating fish is of concern due to the large participation of this food in the diet of traditional fishing communities. The aim of this study was to evaluate the estimated daily intake (EDI) and the incremental lifetime cancer risk associated with Hg and o.p'DDT, p.p'DDT, o.p'DDE, and p.p'DDE in an Amazonian community. The results showed that for Hg, the EDI from carnivorous and detritivorous fish had the highest values, while for pesticides, the EDI from detritivorous fish intake had the highest value. The incremental lifetime cancer risk was below the permitted limit. A recommendation for controlling the high risk of exposure includes the reduction of detritivorous fish ingestion and/or replacement with herbivorous fish, which had lower EDI. We highlight the importance of investigating the human dietary patterns when estimating risk of exposure to Hg and pesticides.

Mercury and stable carbon and nitrogen isotopes in the natal Fur of two Antarctic pinniped species.

Southern elephant seal (SES) and Antarctic fur seal (AFS) are short Southern Ocean food web top predators and are spatial and temporal trend bioindicators of Antarctic Hg bioavailability. Hg, stable isotope composition (δ13C and δ15N) and trophic position (TP) regarding sex were determined using lanugo samples from Antarctic pinnipeds pups (SES n = 35 and AFS n = 11). Hg concentrations in over 50% of the SES pups (mean 5.9 ± 3.1 mg kg-1 dry wt.) are compatible with those found to cause neurologic damage to polar bears in the Arctic. No significant differences regarding sexes for SES or AFS are found based on mean Hg concentrations normalized by body weight. δ15N values and TPs are similar among both species, indicating that gestating SES and AFS mothers feed at the same trophic level. Significantly different δ13C values were found, indicating distinct feeding grounds for mothers belonging to both species when pup lanugo is formed in utero; while SES females like to feed in Antarctic waters, AFS females remain in sub-Antarctic waters. The differences in Hg and δ13C observed for both species reflect not only contrasting feeding habits and anthropogenic Hg inputs, but also maternal foraging strategies.

Trace elements and stable isotopes in egg yolk of green turtles on Rocas Atoll, Brazil.

This study analyzed trace elements (As, Ba, Cd, Cu, Fe, Mn, Pb, Zn) and stable isotopes of carbon and nitrogen in egg yolk samples of female green turtles that nested in Rocas Atoll, Brazil, in 2017 and 2018. The trace elements concentration varied between years, with higher concentrations in 2017, suggesting that the nesting groups come from different foraging sites. The isotopic data indicated high overlap between years (73%), leading to an ambiguous interpretation on the turtles' foraging site. The Normalized Total Load presented a low association (0.01 < R2 < 0.41) with the stable isotopes. The Normalized Total Load that represents the trace element load in egg yolk is a holistic approach that can be applied elsewhere to predict ecotoxicology pathways in any animal species. We recommend a continuous monitoring to verify how the trace elements load behave in the nesting green turtles on Rocas Atoll.

Trace elements in green turtles (Chelonia mydas) from Rocas Atoll, NE Brazil: Baseline reference from a pristine nesting site.

This study presents the first report on the concentration of trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) in the blood and egg fractions of green turtles from Rocas Atoll, a pristine nesting site in NE Brazil. The highest concentrations of all elements were in the blood or shell samples. In order, iron, Zn, Cu, Al and As presented the highest concentrations in all tissues. The nonessential trace elements were below the limit of detection for more than 50% of the yolk (Al, Cd and Pb) and albumen samples (Al, As, Ba, Cd and Pb). This study will serve as a baseline reference for future monitoring of the ecotoxicology of breeding green turtles in the southwestern Atlantic Ocean.

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.

Epidemiological pattern of tattoo skin disease: a potential general health indicator for cetaceans.

The presence of tattoo skin disease (TSD) was examined in 1392 free-ranging and dead odontocetes comprising 17 species from the Americas, Europe, South Africa, New Zealand and Greenland. We investigated whether TSD prevalence varied with sex, age and health status. TSD was encountered in cetaceans from the Pacific and Atlantic Oceans as well as in those from the North, Mediterranean and Tasman Seas. No clear patterns related to geography and host phylogeny were detected, except that prevalence of TSD in juveniles and, in 2 species (dusky dolphin Lagenorhynchus obscurus and Burmeister's porpoise Phocoena spinipinnis), in adults was remarkably high in samples from Peru. Environmental factors and virus properties may be responsible for this finding. Sex did not significantly influence TSD prevalence except in the case of Peruvian P. spinipinnis. Generally, there was a pattern of TSD increase in juveniles compared to calves, attributed to the loss of maternal immunity. Also, in most samples, juveniles seemed to have a higher probability of suffering TSD than adults, presumably because more adults had acquired active immunity following infection. This holo-endemic pattern was inverted in poor health short-beaked common dolphins Delphinus delphis and harbour porpoises Phocoena phocoena from the British Isles, and in Chilean dolphins Cephalorhynchus eutropia from Patagonia, where adults showed a higher TSD prevalence than juveniles. Very large tattoos were seen in some adult odontocetes from the SE Pacific, NE Atlantic and Portugal's Sado Estuary, which suggest impaired immune response. The epidemiological pattern of TSD may be an indicator of cetacean population health.

Debris ingestion by carnivorous consumers: Does the position in the water column truly matter?

The hypothesis that carnivorous consumers associated with the seabed are more likely to ingest marine debris was tested based on stomach content analysis of fish (Trichiurus lepturus and species of Ariidae) and cetaceans (Sotalia guianensis and Pontoporia blainvillei). Among 596 stomach contents, only 22 (3.7%) contained debris. The debris was flexible plastic, nylon yard, paper, latex, styrofoam and cigarette filter. The proportion of stomach contents with debris varied among species: P. blainvillei (pelagic demersal consumer) presented the highest frequency of ingestion (15.7%), while T. lepturus (pelagic consumer), S. guianensis (pelagic consumer) and Ariidae (demersal consumer) presented similar frequencies (1.3-1.8%). Therefore, a feeding site in the water column does not predict the probability of debris ingestion. Concerning these species, this probability seems to be more associated with prey-capture strategies (or feeding behavior), regardless of debris availability in the environment.

Interaction of the Atlantic ghost crab with marine debris: Evidence from an in situ experimental approach.

Sandy beaches pollution by marine debris imposes arguably threats for the biodiversity, but interaction of beach bioindicators (e.g., ghost crabs) with debris has been rarely assessed. We aimed to test whether the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) misidentifies marine debris as food sources. Cigarette butts, straws, popsicle sticks, paper napkins and styrofoams were mixed into solutions with odour of natural and industrialized food. The debris were placed around burrows on beaches with distinct human pressures (low, medium and high-impact). The species interacted with marine debris more frequently in situations of lower human impact, lower prey abundance and larger burrow diameter. These results indicate that in areas with low prey availability and larger individuals, interactions between ghost crabs and debris left by beach visitors and/or transported by winds and currents to low-impact beaches are more likely to occur, mainly near to urbanized areas.

Hg and δ15N in juvenile green turtles from southeastern Brazil (~23°S): Inferences about contamination levels and recruitment to coastal waters.

Total mercury (THg) and δ15N were analysed in liver and muscle of juvenile green turtles (Chelonia mydas) from a foraging site in southeastern Brazil (~23°S) to evaluate contamination levels and make inferences about the timescale that animals were recruited from oceanic to coastal waters. The values for THg and δ15N in liver and muscle were 432.2 and 72.8 µg kg-1 and 10.0‰ and 9.2‰, respectively. THg concentrations in tissues indirectly indicated that the main food resources for this consumer (i.e., macroalgae) had negligible levels of this element. Thus, this foraging site could be considered a pristine area in terms of Hg contamination. The THg and δ15N in liver were derived by more recent food ingestion than those in muscle. The juvenile green turtles that died because of incidental captures in fisheries practiced along this foraging site were individuals newly recruited from oceanic waters.

Can the Atlantic ghost crab be a potential biomonitor of microplastic pollution of sandy beaches sediment?

The objective of the present study was to test whether the Atlantic ghost crab Ocypode quadrata is a reliable biomonitor of microplastic (MP) pollution of beach sediments. To test the hypothesis (H1) that the sediment is the main source of MP ingestion, the proportion of MP types (hard plastic, microfibers, pellet, soft plastic, and extruded polystyrene foam) in the gut content was compared with that on the strandline. The types of MPs in the gut content and sediment had similar proportions; black (~49%) and blue (~45%) microfibers were responsible for this similarity (55%), hence confirming H1. However, the second hypothesis (H2) that prevalence of MP in the gut content is related to its density on beach with distinct urbanization degree was not accepted. These results indicate that high trophic plasticity of the ghost crab and, consequently, multiple-sources of contamination may interfere with its use as a biomonitor of MP pollution.

Trace metals in two commercial shrimps from southeast Brazil: Baseline records before large port activities in coastal waters.

This study presents baseline records of trace metals for two commercial shrimps from the inner continental shelf of southeast Brazil (~22°S). Organisms were sampled in 2004, 10 years before the beginning of large port activities in coastal waters. The concentrations of trace metals in muscle tissues (µg.g-1 w.w.) of Xyphopenaues kroyeri and Artemesia longinaris are as follows: Al: 141.57 and 146.71, Fe: 83.17 and 91.68, Zn: 28.69 and 29.70, Cu: 7.19 and 3.94, Mn: 1.47 and 1.72, Pb: 1.14 and 0.60, V: 0.66 and 0.56, Ni: 0.38 and 0.34, Cr: 0.42 and 0.29, and Cd: 0.15 and 0.14, respectively. Significantly higher concentrations of Cu and Pb were recorded for X. kroyeri. In general, the concentrations are below the maximum permissible limits for metals in fishery/food products, as established by the Brazilian Agency for Sanitary Vigilance (ANVISA), except for Pb and Cr. These baseline records are relevant for future monitoring.

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.

Total mercury, organic mercury and selenium in liver and kidney of a South American coastal dolphin.

Selenium and total and organic mercury were determined in the liver and kidney of franciscana dolphin (Pontoporia blainvillei) incidentally caught in fishing nets along two Brazilian coastal areas (southeast and south). Regional differences in the concentrations of these contaminants were observed in P. blainvillei. Liver showed the highest organic and total mercury. In general, samples of individuals collected at the southern of Brazil had the highest concentrations of selenium and total and organic mercury. No significant gender differences were observed. Growth stage influenced the accumulation of these contaminants in both organs, and hepatic concentrations increased with the body length, according to the sampling area. Molar mercury and selenium concentrations in liver were significantly correlated, with a Se:Hg ratio close to 4. The among-site differences we found may be related to differences in preferred prey, bioavailability in the marine environment, environmental conditions, or these individuals may belong to distinct populations.

Ecological and biological determinants of trace elements accumulation in liver and kidney of Pontoporia blainvillei.

The present work tested whether ecological and biological variables have an influence on the assimilation of trace elements by the tissues of a cetacean from the Western South Atlantic Ocean. No significant differences were observed in the concentrations for both sexes. As individuals from the two sampling areas belong to distinct genetic and morphological populations, animals of similar body length were older on the southeastern than on the southern coast. The liver showed the highest concentrations of mercury, whereas the highest levels of cadmium were found in the kidney. Hepatic mercury, cadmium and selenium in individuals from the south coast were about four times as high as those from the southeast coast. However, arsenic in the liver and kidney were similar in both coastal areas. Hepatic mercury, cadmium and selenium concentrations increased with body length in individuals from the southeastern coast, although no significant correlations (P>0.05) were observed between body length from either area and the renal and hepatic As concentrations. A significant positive linear relationship was observed between molar concentrations of Hg and Se in the liver of all individuals from both areas (r2=0.93; P<0.001), presenting Se:Hg ratios close to 4. Differences found among the concentrations of Hg, Cd and Se in dolphins from both areas were probably due to the preferred prey, bioavailability of elements in each marine environment, and environment variables (water temperature, net primary production). As a consequence, concentrations of trace elements in the tissues of this species can be considered to be a result of the surrounding environment.

Marine debris boost in juvenile Magellanic penguins stranded in south-eastern Brazil in less than a decade: Insights into feeding habits and habitat use.

The Magellanic penguin (Spheniscus magellanicus) is a marine sentinel for the southern Atlantic Ocean that is a proxy of environmental quality. The presence of marine debris (macro-debris) in the stomach contents of emaciated juvenile penguins stranded from 21°S to 23°S was compared at different times (2000 and 2008), and the debris ingestion pathway was determined. The frequency of marine debris in the stomachs doubled in less than a decade, and flexible plastics remained the main ingested item over time (68-70%). The pelagic octopus, Argonauta nodosa, which inhabits the sea surface, was the most important prey species recovered in the stomach contents. The poor physical condition of the penguins that reach the northern migration limit (study area) reduces the diving capacity of the animals and increases their vulnerability to debris ingestion. Considering their preferred prey and physical condition, we conclude that the penguins likely ingested the marine debris in surface waters.