A framework and methods for incorporating gender-related issues in wildlife risk assessment: gender-related differences in metal levels and other contaminants as a case study

Mercury and rare earth elements (REEs) show different spatial trends in feathers of Kentish plover (Charadrius alexandrinus) breeding along the Adriatic Sea coast, Italy

Feather analysis is an ethical and effective method for assessing the exposure of wild birds to environmental contamination due to trace elements and organic pollutants. We used feather to monitor the exposure to three toxic and non-essential metals (Hg, Cd, and Pb) and rare earth elements (REEs) of Kentish plover (Charadrius alexandrinus) breeding in different coastal areas (Veneto, Emilia-Romagna, Marche, Abruzzo, and Apulia) along the Italian coast of the Adriatic Sea. Feathers (n = 113) were collected from April to June. Feather concentrations evidenced a significant exposure to Hg (13.05 ± 1.71 mg kg-1 dw) and REEs (447.3 ± 52.8 ng g-1 dw) in the Kentish plover breeding in Veneto (n = 21) compared to the other coastal areas, with several individuals showing Hg concentrations above the adverse effect (5 mg kg-1 dw) and high-risk (9.14 mg kg-1 dw) thresholds reported for birds. Higher REE concentrations compared to Marche (n = 29), Abruzzo (n = 11) and Apulia (n = 13) were also reported for birds breeding in Emilia-Romagna (474.9 ± 41.9 ng g-1 dw; n = 29). The exposure to Cd and Pb was low in all the coastal areas, and only a few samples (n = 6 and n = 4 for Cd and Pb, respectively) exceeded the adverse effect thresholds (0.1 and 4 mg kg-1 for Cd and Pb, respectively). A significant sex-related difference was observed for REE-concentrations, with females showing higher concentration than males. These data highlight the need to monitor the exposure of the Kentish plover to Hg and REEs, especially in the northern basin of the Adriatic Sea, since these elements might negatively affect species' reproductive success and threaten its conservation.

Metal and metalloid concentrations in wild mammals from SW Europe: European hedgehog (Erinaceus europaeus) and badger (Meles meles)

In recent years, there have been increasing ecological and global concerns associated to Potentially Toxic Elements (PTEs). Thus, the relevance of wild mammals as biomonitors has been globally recognised. In the present study, Cd, Pb, Hg, Zn and As concentrations were quantified in European hedgehog and badger inhabiting SW Europe, and cumulative trends in relation to age and sex were evaluated. Liver and kidney samples were collected, mineralised and PTE content was determined by ICP-MS. Zn was the most abundant element quantified in both organs (239 and 89.8 mg kg-1 for hedgehogs and 179 and 164 mg kg-1 dw for badgers). In hedgehogs, very high Hg concentration were quantified (4.35 and 15.5 mg kg-1 dw in liver and kidney), and Cd was the most abundant for badgers (4.70 and 7.61 mg kg-1 dw in liver and kidney). Positive correlations were observed for the concentrations of PTE in the organs of both species. Age-dependence increased only Cd concentration, with levels in adult kidneys being significantly higher. In this study, European hedgehog and badger were used as biomonitors for the determination of PTEs to provide current reference values in relatively non-polluted areas of SW Europe, and to enhance the use of these species for future ecotoxicological studies.

Sex-biased response of pollution biomarkers in fish: Insights from the killifish Poecilia vivipara

Copper ions (Cu) are one of the most frequent trace-contaminants found in Brazilian waters and, although considered as an essential element, in high concentrations can accumulate and induce toxicity. Biomarkers are important tools that can be used to assess these impacts, but to be considered trustworthy, they have to be previously tested in target organisms through laboratory studies under controlled conditions. However, many of these experiments are conducted using only males, as it is believed that the hormonal variation of females can bias the results, increasing data variability. Notwithstanding, few studies have actually tested this hypothesis, highlighting the importance of considering and measuring the role of sex in ecotoxicological studies. The aim this study was to evaluate the influence of sex on biomarkers classically used in environmental monitoring programs using the fish Poecilia vivipara as model. For this, females and males were exposed for 96 h to two Cu concentrations (9 and 20 μg/L) and a control group. In liver and gills, Cu accumulation, total antioxidant capacity (TAC) and lipid peroxidation (LPO) were evaluated. In addition, samples of peripheral blood were used for neutrophil to lymphocyte ratio determination, a measure of the onset of secondary stress. Results show that Cu hepatic accumulation did not differ between females and males, but higher levels of this metal were observed in exposed animals compared to control fish. Additionally, interactive effects were observed for hepatic LPO, as males showed elevated oxidative damage in comparison to females. Moreover, Cu exposure elevated hepatic LPO relative to control only in males, but this increase in oxidative damage was not accompanied by changes in liver TAC. On the other hand, differences in branchial Cu accumulation and LPO were not observed. Conversely, control females showed elevated TAC in comparison to control males, but Cu exposure eliminated this difference. Cu exposure also induced an increase in the N:L ratio, indicating the presence of a secondary stress response unrelated to sex. Ultimately, the findings of this study demonstrate that sex can influence the response of biomarkers that are typically used in ecotoxicological investigations in a multifaceted manner. As a result, using animals from a singular sex in such studies may result in consequential outcomes, potentially leading to underestimation or overestimation of results.

Metal contents in house geckos (Squamata: Gekkonidae) from industrial and urban areas of southern Tamaulipas, Mexico and western Andalucía, Spain, may reflect airborne metal pollution

House geckos share living quarters with humans in the tropical and subtropical regions inhabited by these reptiles. Gecko behavior, biological traits, continuous exposure to suspended particulate matter 0 µm in diameter (PM₁₀) and dust, as well as status as exotic species, motivated the choice of these species to examine environmental exposure to ambient air pollutants, in particular metals, and subsequent accumulation in these organisms. One part of the study was conducted in Tamaulipas (Mexico) where Hemydactylus frenatus is abundant in urban and industrial environments, the other part was conducted in Andalucia (Spain) where Tarentola mauritanica is found in similar environments. Adult geckos were collected on buildings in locations affected by various air pollution sources. For both species, higher metal contents were observed in whole-body (including digestive tracts) analysis and were markedly different between collection sites. Contents in tails, digestive tracts, and carcasses without digestive tracts were not correlated. Based on contamination factor values, bioaccumulation in H. frenatus tissues occurred for 12 of the 15 metals analyzed. Data suggest that H. frenatus might serve as a biomonitor for Cu, Ni, Pb, Cr, Li, and V, whereas T. mauritanica might be a biomonitor for Cu, Ni, Pb, and Cr. To our knowledge, metal contents for H. frenatus are reported here for the first time. House gecko data could be integrated into a highly representative monitoring system and health risk assessments related to air quality in residential areas.

Tissue distribution and association of heavy metal accumulation in a free-living resident passerine bird tree sparrow Passer montanus

Passerine birds have been increasingly used as effective sentinels of ecosystem contamination. They can provide direct evidence of the bioavailability and accumulation of heavy metal elements in the environment. In this study, the bioaccumulation of four heavy metals (Cu, Zn, Pb, and Cd) and Ca in different organs and tissues (feathers, internal organs, skeletons, and muscles) of an urban bird, tree sparrow (Passer montanus), collected from a polluted site [Baiyin (BY)] and a relatively unpolluted site [Liujiaxia (LJX)], and their associations were investigated. There were significantly higher and lower concentrations of heavy metals and Ca, respectively, in different organs and tissues of sparrows in BY than those in LJX. However, except for Pb, the heavy metal levels were below the threshold of sublethal effects. Age-dependent variations in metals were quantified, and it was found that adult bird contained higher concentration of different organs and tissue metals, except for feathers, compared with nestlings and juveniles. The tissue distribution of heavy metals in sparrows of different ages and sex was similar in the two study sites, and heavy metal elements were mainly accumulated in the feathers. This study further investigated the correlation between heavy metals in different organs and tissues and found that the correlations between them were strong in nestlings and adults but weak in juveniles. In addition, Pb and Cd in internal organs, skeletons, and muscles of young sparrows can be estimated using feathers, whereas Cu and Zn were found in adult sparrows. Altogether, our results suggest that tree sparrows will serve as valuable biomonitors of environmental heavy metal pollution and will underscore the importance of tissue types in avian ecotoxicology field studies.

J, Jacobsen JK, Scordino JJ, Lang AR, Baugh KA, Bolton JL, Brüniche-Olsen A, Calambokidis J, Martínez-Aguilar S, Subbiah S, Gribble MO, Godard-Codding CAJ. Influence of Life-History Parameters on Persistent Organic Pollutant Concentrations in Blubber of Eastern North Pacific Gray Whales (Eschrichtius robustus)

Exposure to persistent organic pollutants (POPs) can significantly impact marine mammal health, reproduction, and fitness. This study addresses a significant 20-year gap in gray whale contaminant monitoring through analysis of POPs in 120 blubber biopsies. The scope of this substantial sample set is noteworthy in its range and diversity with collection between 2003 and 2017 along North America's west coast and across diverse sex, age, and reproductive parameters, including paired mothers and calves. Mean blubber concentrations of polychlorinated biphenyls (∑PCBs), dichlorodiphenyltrichloroethanes (∑DDTs), and chlordanes (∑CHLs) generally decreased since previous reports (1968-1999). This is the first report of polybrominated diphenyl ethers (PBDEs) and select hexachlorocyclohexanes (HCHs) in this species. Statistical modeling of the 19 most frequently detected compounds in this dataset revealed sex-, age-, and reproductive status-related patterns, predominantly attributed to maternal offloading. Mean POP concentrations differed significantly by sex in adults (17 compounds, up to 3-fold higher in males) but not in immatures (all 19 compounds). Mean POP concentrations were significantly greater in adults versus immatures in both males (17 compounds, up to 12-fold) and females (13 compounds, up to 3-fold). POP concentrations were detected with compound-specific patterns in nursing calves, confirming maternal offloading for the first time in this species.

The price of persistence: Assessing the drivers and health implications of metal levels in indicator carnivores inhabiting an agriculturally fragmented landscape

Patterns and practices of agricultural expansion threaten the persistence of global biodiversity. Wildlife species surviving large-scale land use changes can be exposed to a suite of contaminants that may deleteriously impact their health. There is a paucity of data concerning the ecotoxicological impacts associated with the global palm oil (Elaeis guineensis) industry. We sampled wild Malay civets (Viverra tangalunga) across a patchwork landscape degraded by oil palm agriculture in Sabah, Malaysian Borneo. Using a non-lethal methodology, we quantified the levels of 13 essential and non-essential metals within the hair of this adaptable small carnivore. We robustly assessed the biological and environmental drivers of intrapopulation variation in measured levels. Metal concentrations were associated with civet age, weight, proximity to a tributary, and access to oxbow lakes. In a targeted case study, the hair metal profiles of 16 GPS-collared male civets with differing space use patterns were contrasted. Civets that entered oil palm plantations expressed elevated aluminium, cadmium, and lead, and lower mercury hair concentrations compared to civets that remained exclusively within the forest. Finally, we paired hair metal concentrations with 34 blood-based health markers to evaluate the possible sub-lethal physiological effects associated with varied hair metal levels. Our multi-facetted approach establishes these adaptable carnivores as indicator species within an extensively altered ecosystem, and provides critical and timely evidence for future studies.

A U-Turn for Mercury Concentrations over 20 Years: How Do Environmental Conditions Affect Exposure in Arctic Seabirds?

Mercury (Hg) is highly toxic in its methylated form (MeHg), and global change is likely to modify its bioavailability in the environment. However, it is unclear how top predators will be impacted. We studied blood Hg concentrations of chick-rearing black-legged kittiwakes Rissa tridactyla (2000-2019) in Svalbard (Norway). From 2000 to 2019, Hg concentrations followed a U-shaped trend. The trophic level, inferred from nitrogen stable isotopes, and chlorophyll a (Chl a) concentrations better predicted Hg concentrations, with positive and U-shaped associations, respectively. As strong indicators of primary productivity, Chl a concentrations can influence production of upper trophic levels and, thus, fish community assemblage. In the early 2000s, the high Hg concentrations were likely related to a higher proportion of Arctic prey in kittiwake's diet. The gradual input of Atlantic prey in kittiwake diet could have resulted in a decrease in Hg concentrations until 2013. Then, a new shift in the prey community, added to the shrinking sea ice-associated release of MeHg in the ocean, could explain the increasing trend of Hg observed since 2014. The present monitoring provides critical insights about the exposure of a toxic contaminant in Arctic wildlife, and the reported increase since 2014 raises concern for Arctic seabirds.

Effects of age and sex on the content of heavy metals in the hair, liver and the longissimus lumborum muscle of roe deer Capreolus capreolus L

The aim of the study was to investigate the effects of age and sex on the content of heavy metals (Pb, Cd, Zn and Cu) in the hair, liver and the longissimus lumborum muscle of roe deer (Capreolus capreolus L.). In addition, correlations between heavy metals in individual tested matrices were studied as well as an attempt was made to explain the reasons for their accumulation in specific research matrices. The levels of Zn and Cu were measured using atomic absorption spectroscopy (F-AAS). The levels of Pb and Cd were analysed by means of electrothermal atomic absorption spectroscopy (ET-AAS). In the own research, sex-related statistically significant differences in concentrations of analysed elements were confirmed. Higher levels of the elements were observed in samples collected from does (except for Cd in the liver samples of 6-7-month-old male fawns) but only in some cases, these values were statistically significantly higher. In some cases, age-related differences in the content of individual metals were also confirmed. Age-dependent increased Pb levels in the muscle and liver were reported in 6-7-month-old, <3-4-year-old, <5-6-year-old males. Similar relationships were confirmed for Zn in the bucks' muscles. In the group of does, the increase in heavy metal concentrations with aging was observed for Zn in the muscle and for Pb in the liver. In the other cases, the trend of age-related level changes regarding heavy metals was not clearly demonstrated. Significant positive correlations between Cu and Cd were found for all samples, and significant negative correlations of Cu with Pb were found for the hair and liver. There was a negative correlation of Zn with Cu in all matrices. The study also revealed a negative correlation between Zn and Pb in muscle and a strong significant negative correlation between Zn and Cd in hair and in the liver.

Accumulation of selected metals and concentration of macroelements in liver and kidney tissues of sympatric golden jackal (Canis aureus) and red fox (Vulpes vulpes) in Somogy County, Hungary

This study examined the concentrations of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn in the liver and kidney samples of golden jackals (n = 163) and red foxes (n = 64). Additionally, we studied how sex affected element concentration in both species, and in the case of golden jackals, how concentration levels were affected by age.Liver was the most important storage organ for Cu, Fe, Mn, and Zn, while kidney for Cd and Na in jackals and foxes.We found no sex-related differences in concentration of any of the selected elements in fox samples. In jackals, the mean concentrations of Al, Mn, and Zn were significantly higher in kidneys of males, while Zn and Cu had higher concentrations in female livers. Our results suggest bioaccumulation processes do not occur in mesocarnivores.Lead and Cd concentrations fell within ranges accepted as normal for canine species and were below toxic levels in the organs of the examined species. Concentrations of Cr, Cu, Fe, Mn, and Zn were far below the toxic levels in both organs of both species, with a slight sign of deficiency of Fe, Mn, and Zn in jackal and fox kidneys. In comparison with toxicity levels and results from other European study sites, the current study demonstrated that species living in the examined area of Somogy County, Hungary, are generally exposed to low levels of environmental contamination.

Consequences of combined exposure to thermal stress and the plasticiser DEHP in Mytilus spp. differ by sex

Little is known about the combined effect of environmental factors and contaminants on commercially important marine species, and whether this effect differs by sex. In this study, blue mussels were exposed for seven days to both single and combined stressors (i.e., +3 °C elevated temperature and two environmentally relevant concentrations of the plastic softener DEHP, 0.5 and 50 μg/l) in a factorial design. Males were observed to be more sensitive to high temperature, demonstrated by the significant increase in out-of-season spawning gonads and higher gene expression of the antioxidant catalase and the estrogen receptor genes. On the other hand, while the gametogenesis cycle in females was more resilient than in males, DEHP exposure altered the estrogen-related receptor gene expression. We show that the combined stressors DEHP and increased temperature, in environmentally relevant magnitudes, have different consequences in male and female mussels, with the potential to impact the timing and breeding season success in Mytilus spp.

Sex-related and spatial variation in trace elements in feathers of the Kentish plover (Charadrius alexandrinus) from different coastal areas of the Iberian Peninsula

This study investigated the sex-related and spatial variation in trace elements concentrations in feathers of the Kentish plover (Charadrius alexandrinus) inhabiting different coastal locations in the Iberian Peninsula. Feathers were sampled in a total of 50 breeding birds from 7 different locations: 3 on the Mediterranean coast (n=18), 1 on the Atlantic coast of Andalusia (n=9) and 3 on the NW Atlantic coast (n=23). The feathers were analyzed to determine the concentrations of Al, Cr, Mn, Cu, Zn, As, Se, Cd, Hg and Pb. All of the trace elements were present at detectable concentrations, and the mean concentrations of Al, Zn and Cu were highest of those considered. The coastal section had a significant effect on 5 elements (Mn, Cu, As, Cd and Pb). The mean concentrations of almost all of the trace elements were highest in the birds from Andalusia, intermediate in the birds from the Mediterranean area and, in general, lowest in the birds from the NW Atlantic coast. Females showed significant higher Mn concentrations and high levels of exogenous elements (Al and As) in contrast with males. Less preening activity during the day of female birds, when they are occupied in incubating eggs, could favour higher concentrations of exogenous trace elements. The high levels of several trace elements observed in the samples from Mediterranean and Atlantic coast of Andalusia may pose a serious threat to these populations.

Consequences of sodium dodecyl sulfate exposure on the antioxidant status and steroidogenesis in fish gonad

A native Indian catfish (Heteropneustes fossilis) and an Indian major carp (Cirrhinus cirrhosus) were treated with sodium dodecyl sulfate (SDS) to elucidate its consequences on antioxidant status and sex steroid synthesis. Fishes were exposed to 1/10th of LC₅₀ of SDS for 30 days. Different enzymatic and non-enzymatic antioxidants, major sex steroids, steroidogenic enzymes, gonadosomatic index (GSI), and serum cortisol level were measured in both male and female fishes. Levels of enzymatic and non-enzymatic antioxidants altered significantly in both the fish species. Steroid hormones in both male and female fishes decreased significantly in the SDS-treated group. Profiles of steroidogenic enzymes (hydroxysteroid dehydrogenase; 3β-HSD and 17β-HSD) show significant decrease in the SDS treatment group in both carp and catfish than that of the control group irrespective of sexes. GSI also decreases significantly in the SDS-treated group when compared with the control group in spawning phase of carp and catfish irrespective of sexes. Serum cortisol level was increased significantly after SDS exposure. Higher level of cortisol was noted in the spawning phase than that of pre-spawning phase. Current study proves that SDS could interrupt the normal steroidogenesis process in fish, leading to impaired sex hormone production. Detrimental effect of SDS was noted to be more prominent on female steroidogenesis than that of male fish. A species or season-specific variation in steroidogenesis was also observed which indicates that SDS-induced toxicity depends on the sexual status of the specific fish species.

Population- and sex-specific sensitivity of the marine amphipod Allorchestes compressa to metal exposure

The sensitivity to contaminants of natural populations varies greatly depending on their historical exposure and on the sex of the individual. These factors result in great uncertainty in ecotoxicological risk assessments and challenge the protection of marine biodiversity. This study investigated the role of background pollution in the environment in shaping the sensitivity of males and females of the common marine amphipod Allorchestes compressa to the common trace marine pollutant, copper (Cu). Female and male amphipods were collected from two sites: Geelong (the polluted site) and Clifton Springs (the clean site). Amphipods were exposed to Cu treatments of 0, 50, 100, and 250 μg/L for 10 days, followed by a 10-day recovery period. Cu-exposed males from Geelong showed a reduction in feeding rate at a higher Cu concentration than males from Clifton Springs, suggesting that they have a higher tolerance to Cu than males from Clifton Springs. This can be explained by their higher base level of metallothioneins (MTs) and glutathione-S-transferase (GST), the key physiological responses for detoxification and defence against damages from Cu toxicity. Males showed a higher tolerance to Cu than females. This pattern was similar in both populations, which may be associated with a higher level of GST. During the recovery period, only males from Geelong fully recovered to the control level. Our results emphasize the importance of considering population- and sex-specific sensitivity of invertebrates to contaminants in ecotoxicological risk assessments.

Sex and sex-related differences in gamete development progression impinge on biomarker responsiveness in sentinel mussels

In marine pollution monitoring, the biomarkers recorded in sentinel organisms are influenced by natural confounding factors that may jeopardise their interpretation. Among these confounding factors, little is known about the influence of sex along the annual reproductive cycle. The present investigation aims at contributing to understand how sex and sex-related differences in gamete development progression impinge on biomarker baseline values and on biomarker responsiveness to pollution in sentinel mussels. Mussels (Mytilus galloprovincialis) were collected from a relatively clean locality and from a chronically polluted site in the Basque Coast (Bay of Biscay) in January, April, August and November. Sex and gametogenesis stages were determined for each mussel. Tissue concentration of metals and PAHs was analysed. A battery of biomarkers was investigated: cytochrome c oxidase, pyruvate kinase and phosphoenolpyruvate carboxykinase enzyme activities; levels of protein carbonyls, malondialdehyde and 4-hydroxy-2-nonenal; lysosomal enlargement and membrane stability; intracellular neutral lipid accumulation; cell type composition and thinning of the digestive gland epithelium; and survival-in-air. Sex- and reproductive stage-related differences were found in bioaccumulation and in the values and responsiveness of most of the biomarkers. However, the patterns of sex-related differences were not consistent across all biomarkers. The differences in the biomarker responses between females and males also depended on the season, reflecting the progression of the gametogenesis cycle. Thus, selecting mussels of one specific sex does not seem to be a crucial requisite to carry out biomarker-based monitoring; yet, it is highly recommended to identify sex condition and gamete developmental stage of each mussel to test for the potentially confounding effects of sex, reproductive status and sex-related variability along the reproductive cycle.

Multifactorial Analysis of Environmental Metabolomic Data in Ecotoxicology: Wild Marine Mussel Exposed to WWTP Effluent as a Case Study

Environmental metabolomics is a powerful approach to investigate the response of organisms to contaminant exposure at a molecular scale. However, metabolomic responses to realistic environmental conditions can be hindered by factors intrinsic to the environment and the organism. Hence, a well-designed experimental exposure associated with adequate statistical analysis could be helpful to better characterize and relate the observed variability to its different origins. In the current study, we applied a multifactorial experiment combined to Analysis of variance Multiblock Orthogonal Partial Least Squares (AMOPLS), to assess the metabolic response of wild marine mussels, Mytilus galloprovincialis, exposed to a wastewater treatment plant effluent, considering gender as an experimental factor. First, the total observed variability was decomposed to highlight the contribution of each effect related to the experimental factors. Both the exposure and the interaction gender × exposure had a statistically significant impact on the observed metabolic alteration. Then, these metabolic patterns were further characterized by analyzing the individual variable contributions to each effect. A main change in glycerophospholipid levels was highlighted in both males and females as a common response, possibly caused by oxidative stress, which could lead to reproductive disorders, whereas metabolic alterations in some polar lipids and kynurenine pathway were rather gender-specific. This may indicate a disturbance in the energy metabolism and immune system only in males. Finally, AMOPLS is a useful tool facilitating the interpretation of complex metabolomic data and is expected to have a broad application in the field of ecotoxicology.

Rare earth element bioaccumulation in the yellow and silver European eel (Anguilla anguilla): A case study in the Loire estuary (France)

In the present work, rare earth elements (REEs) were measured in European eel muscles (Anguilla anguilla) from the Loire estuary in France. This study site is characterized by a large anthropogenic pressure with potential activities releasing REEs such as oil refineries, aeronautic and naval industries, wind turbine industries, hospitals with magnetic resonance imaging and coal-fired power plants. These activities may lead to increased REE concentrations in sediments the primary habitat of European eels. In the present work, REE bioaccumulation was evaluated by determining the concentrations in yellow and silver eel muscles sampled at three different locations in the Loire estuary and at two periods (2011/2012 and 2018/2019). The aims of this study were the understanding of the spatio-temporal influences (sampling site and sampling period) and intraspecific variations (age, sex, sexual maturation, length, weight, and parasitism) on the whole REE bioaccumulation. The mean value of the sum of REE concentrations (∑REEs) was 2.91, 6.48 and 12.60 µg/kg of muscle from respectively yellow eels, female silver eels and male silver eels fished in 2018/2019. The results showed that silver males accumulated more REEs than silver females and silver eels accumulate more REEs than yellow ones. Regarding the determination of spatio-temporal variations, an increase of REE concentrations for silver eel muscles between the two periods was observed, certainly related to the increase of REE uses. Finally, a trend of higher contamination of eels sampled in the downstream of Nantes was noticed for yellow eels.

Trace element contamination in fish impacted by bauxite red mud disposal in the Cassidaigne canyon (NW French Mediterranean)

From 1966 to 2015, the Gardanne alumina refinery discharged some 20 million tons of bauxite residue (called red mud) into the Cassidaigne Canyon (northwest French Mediterranean) with impacts on local ecosystem functioning. Although these red muds contained high levels of trace elements (TE), in particular titanium (Ti), vanadium (V), aluminum (Al) and arsenic (As), surprisingly, their impacts on fish contamination levels and the risk related to fish consumption have been little studied until now. Here, 11 trace elements (Al, As, Cd, Cr, Co, Cr, Mn, Ni, Pb, Ti and V) were analyzed in muscle and, when possible, liver, from 1308 fish of 26 species from an impacted zone in the vicinity of the Cassidaigne Canyon and a reference zone, unaffected by red mud disposals. Moreover, 66 arsenic speciation analyses were performed. Although the impact of human activities on the levels of fish contamination by trace elements is generally not easy to assess in situ because it is blurred by interaction with biological effects, we highlighted significant contamination of the fish species collected from the Cassidaigne Canyon, especially by the main trace elements attributable to the discharges of the Gardanne alumina refinery, namely Al, V and Ti. Moreover, inorganic toxic As concentrations were higher in the impacted zone. The results of this baseline research also confirmed the concern previously raised regarding Hg in Mediterranean organisms and that trace element contamination levels in fish are generally negatively related to fish length for all TE except Hg.

Feathers of Humboldt penguin are suitable bioindicators of Rare Earth Elements

Rare earth elements (REEs), also called lanthanides, are emerging contaminants worldwide, due to their unique physical and chemical characteristics that make them essential in a variety of industrial applications. However, there is still a gap in the knowledge of occurrence and accumulation of REEs in biota, and no investigations have yet been performed in penguin feathers, which have already been widely utilized as a non-invasive tool for the biomonitoring of trace elements. The concentrations of 16 REEs were investigated in a colony of Humboldt penguins (Spheniscus humboldti) housed at the Acquario di Cattolica (Italy). Multielement determination of REEs was performed by an Inductively Coupled Plasma-Mass Spectrometer after a microwave digestion of feathers. As this colony lives indoors in a controlled environment, it was the ideal choice for studying lanthanide occurrence in penguin feathers. Since there is a strict link between metal levels in feathers and the diet of penguins, their food (capelin) was also tested for REEs. Chondrite normalized values revealed the same pattern for REEs in feathers and fish, but REE concentrations were an order of magnitude higher in penguin feathers, demonstrating the suitability of this tissue as a bioindicator of REEs.

The Role of Sexual Dimorphism and Tissue Selection in Ecotoxicological Studies Using the Riparian Spider Tetragnatha elongata

Tetragnathid spiders (Tetragnatha spp.) found in riparian habitats have recently been used as bioindicators of sediment contamination and insect-mediated contaminant flux. We investigated whether sexual dimorphism (size and behavior) influenced the female:male ratio in composite samples, stable isotope ratios (carbon [δ¹³C], nitrogen [δ¹⁵N]), and Hg concentrations in the southern United States. Additionally, we explored whether biomass for contaminant analysis could be preserved by using the legs of tetragnathids as a surrogate for whole-body δ¹³C and δ¹⁵N signatures. We found that female tetragnathids were significantly larger than male spiders and represented a larger proportion of spiders collected at all sites. However, despite the difference in size between sexes, no differences in growth dynamics, isotopic signatures (δ¹³C and δ¹⁵N), or mercury concentrations were observed. It was determined that the leg of a tetragnathid can accurately represent the stable isotope signature of an entire spider.

Micro- and macroelement contents in the liver of farm and wild animals and the health risks involved in liver consumption

The paper presents the macroelement (Al, Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn) and microelement (As, Cd, Co, Cr, Hg, Mo, Ni, Pb, and Sn) contents found in the liver of wild animals (boar and deer) and farm animals (rabbit, chicken, duck, cow, goat, and turkey). Statistically, the differences in element contents between the two groups were not significant (at p = 0.05), with the exception of Fe, K, Mg, Cd, Hg, Mo, and Pb. The liver of farm animals contained more Al, Cu, K, Mg, Na, Cr, and Sn, while the content of the remaining elements was higher in wild animals. An analysis of correlations between element content and age in wild animals (boar) showed that Pb and Al content increases with age, while Na and Cr contents decrease significantly. Comparisons between the test results and the maximum limits allowed by law showed that, in the case of wild animals, the regulatory limits were exceeded in 18% (for Cd and Cu) and 9% (for Hg) of the liver samples analyzed. In the case of farm animals, the limits for micro- and macroelement contents were not exceeded. The hazard index (HI) values for farm animals were lower than for wild animals, with regard to consumption by both children and adults. Based on the HI values calculated, it seems recommendable that consumption of the liver (preferably from farm animals) by children be limited to once weekly. For adults, the liver can be a valuable source of elements such as Zn, Fe, and Cr, which may be an indication for more frequent consumption.

Evidence of accumulation and elimination of inorganic contaminants from the lachrymal salt glands of leatherback sea turtles (Dermochelys coriacea)

Plasma osmolalities of marine vertebrates are generally lower than the surrounding medium; therefore, marine organisms must cope with the osmoregulatory challenges of life in a salty environment. The salt glands serve to maintain osmotic and ionic homeostasis in a number of lower marine vertebrates. One marine reptile, the leatherback sea turtle (Dermochelys coriacea), ingests excessive amounts of salts due to their diet of gelatinous zooplankton. Outside of the normal osmoregulatory function of the salt gland, little research has been conducted on contaminant accumulation and excretion in this organ. Here, we established arsenic, cadmium, lead, mercury, and selenium concentrations in red blood cells (RBCs) and salt gland secretions (SGSs) of nesting leatherbacks. We also collected salt glands from different life stage classes of dead stranded leatherbacks from the western Atlantic Ocean to determine if inorganic contaminants accumulate in this organ. Using non-metric multidimensional scaling and regression analyses, we determined that RBC and SGS inorganic contaminant concentrations were not correlated. Additionally, RBCs showed significantly higher concentrations of these contaminants in comparison to SGSs, likely due to the affinity of inorganic contaminants for the heme group of RBCs. Lastly, we found that salt gland cadmium and mercury concentrations tended to increase with increasing curved carapace length (CCL) in stranded leatherbacks. Our results indicate that different physiological mechanisms determine the distribution of inorganic contaminants in blood and SGSs. Increases in salt gland contaminant concentrations with increasing CCL suggest this organ as a potential target for accumulation.

Concentrations of cadmium and lead, but not zinc, are higher in red fox tissues than in rodents-pollution gradient study in the Małopolska province (Poland)

The main purpose of our research was to assess the chronic exposure of red foxes to Cd, Pb and Zn. We have determined concentrations of these metals in the kidney, liver and muscle of 36 red foxes hunted between December 2002 and March 2003 in differently polluted areas in southern Poland. Tissue concentrations of Pb and Cd in the red foxes significantly co-varied with concentrations of these elements in the soil, and differed between the tissues. We compared concentrations of Pb, Cd, and Zn in red foxes with two rodent species, Apodemus flavicollis and Myodes glareolus, trapped simultaneously in the same area. Concentrations of Pb and Cd appeared significantly higher in the red foxes than in the rodents, but the slopes of the relationship between metal concentrations in tissues and in soil were similar in all species. This indicates that extrapolation from results of monitoring studies conducted on rodents to mammalian carnivores is possible but requires applying an extrapolation factor.

Mercury (Hg), Lead (Pb), Cadmium (Cd), Selenium (Se), and Arsenic (As) in Liver, Kidney, and Feathers of Gulls: A Review

Mercury (Hg), lead (Pb), cadmium (Cd), selenium (Se), and arsenic (As) are metals or metalloids of high concern because of their effects on the environment and, specially, their potential toxicity on the animals inhabiting there. Due to their relevance, these elements have been object of several biomonitoring studies in different animal species around the world. Birds are widespread and, as species, are able to supply specific and relevant information about the regions where they live, being useful as bioindicators, as long as they are not birds with a strong migratory character. The main goal of this review is to summarize data collected from different studies using seabirds, paying special attention to gulls, in order to be helpful for coming studies and regulatory affairs.Several tissues have been used to evaluate Hg, Cd, Pb, Se, and As concentrations in seabirds, being focused the present review in those analyzing the liver, kidneys, and feathers. The most frequently analyzed tissue for Hg was the liver, followed by feathers, and finally kidney. For Cd levels, most of the studies were carried out in the liver, followed by feathers and kidneys. Pb, Se, and As levels were determined to a lesser extent. Feathers should be taken carefully as indicator of accumulation of pollutants, since procedure during analysis may lead to controversial results.Some authors reported that interspecific differences in the exposure of elements are determined by multiple factors, including properties of the contaminant, species, feeding habits, migratory status, sex, and age.The present review provides a comprehensive overview of the analyzed elements' occurrence in different species of seabirds, including gulls. Therefore, it can be a useful database providing for Hg, Pb, Cd, Se, and As levels in different tissues of seabirds.

Concentrations of chlorinated pollutants in adipose tissue of yellow-legged gulls (Larus michahellis) from Spain: Role of gender and age

Concentrations of 7 different polychlorinated biphenyl (PCB) congeners, and eleven organochlorine pesticides (OCPs) and metabolites, including DDTs (dichlorodiphenyltrichloroethane), HCHs (hexachlorocyclohexane isomers), Endosulfan, Endosulfan sulfate, Endrin, Dieldrin and HCB (hexachlorobenzene), were determined in adipose tissue of 57 yellow-legged gulls collected from NW and N Spain. Furthermore, the possible differences due to two endogenous factors, age and gender, were determined. All the analyzed PCBs were detected in over 66% of the samples, with levels of 291.9 (PCB 180), 34.5 (PCB 118), 0.7 (PCB 28), 432.6 (PCB 153), 225.5 (PCB 138), 1.3 (PCB 101) and 0.4 (PCB 52) µg/kg of adipose tissue. With respect to the OCPs and metabolites, only 4,4'-DDE and HCB were detected in more than 50% of the samples, with means of 360.6 and 2.5 µg/kg of adipose tissue, respectively. From all the considered contaminants, only 4,4'-DDE levels presented significant differences depending on the gender, with females showing higher values than males (p < 0.01). Significant differences (p < 0.001) were also found related to age for the levels of PCBs 180, 138, 101, 28 and 153, as well as 4,4'-DDE, with adult levels being higher than those in young birds. The results of the present study constitute a baseline to better assess the environmental impacts of PCB and OCP contamination at other coastal sites for future biomonitoring studies, with particular emphasis on gender- and age-related differences.

Concentrations of Cadmium, Copper, and Zinc in Macrobrachium rosenbergii (Giant Freshwater Prawn) from Natural Environment

This study analyzed the levels of cadmium (Cd), copper (Cu), and zinc (Zn) by the flame atomic absorption spectrophotometer (FAAS), in the muscle tissues, exoskeletons, and gills from freshwater prawn (Macrobrachium rosenbergii) (n = 20) harvested from natural habitat in Kerang River, Malaysia on 25th November 2015. Significant increase of the metals level in muscle tissue and gill (r > 0.70, p < 0.05) were observed with increase in length except for Cu in gills. No relationship was found between metals level in exoskeleton and length. The concentrations of Cd, Cu and Zn were significantly higher (p < 0.05) in males (muscle tissues and exoskeleton) except for Cd in exoskeleton. In gills, only Cu was significantly higher (p < 0.05) in female than male. All samples contained metals below the permissible limit for human consumption (i.e., Cd < 2.00 mg/kg; Cu < 30.00 mg/kg; Zn < 150 mg/kg). Annual metals monitoring in prawn and environmental samples is recommended to evaluate changes of metals bioaccumulation and cycling in the system, which is useful for resources management.

Indices of stress and immune function in Arctic barnacle goslings (Branta leucopsis) were impacted by social isolation but not a contaminated grazing environment

In many areas around the Arctic remains and spoil heaps of old mines can be found, which have been abandoned after their heydays. Runoff from tailings of these abandoned mines can directly contaminate the local environment with elevated concentrations of trace metals. Few studies have investigated the possible negative effects of contaminants on Arctic terrestrial animals that use these areas. Trace metals can accumulate in animals and this accumulation has been linked to negative effects on fitness. Both, the hypothalamus-pituitary-adrenal (HPA) axis and/or the immune system have been named as possible underlying causes for these observations. Free-living animals are often exposed to multiple stressors simultaneously, however, and this is often not considered in studies on the effects of contaminants on animal physiology. Here, we performed a study on Spitsbergen (Svalbard) taking both potential effects of trace metal contamination and social stress into account. We investigated experimentally effects of exposure to contaminants from a historic coal mine area on plasma corticosterone levels and on four innate immune parameters (haemolysis, haemagglutination, haptoglobin-like activity and nitric oxide) before and after social isolation in human-raised barnacle goslings (Branta leucopsis). Baseline corticosterone and immune parameters were not affected by mine-exposure. After social isolation, mine goslings tended to show decreased haemagglutination in comparison with control goslings, but we detected no difference in the other measures. Social isolation increased corticosterone and decreased haptoglobin-like activity in all goslings. Immunology and corticosterone levels of barnacle goslings thus seem unaffected, at least on the short term, by Arctic coal mining contamination.

Apex predatory mammals as bioindicator species in environmental monitoring of elements in Dinaric Alps (Croatia)

Tissue element investigations of apex terrestrial mammals are very scarce in Europe. We quantified 16 essential and nonessential elements in the kidney cortex, liver, and muscle tissue of 467 brown bears (Ursus arctos), 125 gray wolves (Canis lupus), one Eurasian lynx (Lynx lynx), and three golden jackals (Canis aureus) from Croatia by inductively coupled plasma mass spectrometry (ICP-MS). Renal cadmium (0.6% of animals) and lead (1%) and hepatic lead (5%) were found in toxicologically relevant levels for mammals only in bears, while the other elements were within normal range. The association of age, sex, season, and region with measured tissue elements in bear and wolf was estimated by multiple regression analyses. Age-related accumulation of cadmium was observed in bears and wolves. Lead tissue content increased with the age of bears but declined in wolves. Female bears and wolves had higher arsenic, iron, and thallium than males in some tissues. Also, cadmium, mercury, copper, zinc, selenium, molybdenum, and uranium were more abundant only in female bears. Male bears had higher potassium, zinc, and magnesium, while male wolves had higher calcium in some tissues compared to female wolves. Seasonal differences were mainly observed for bears' tissues and region-specific differences only in wolves. The bear kidneys had the highest levels of cobalt, copper, molybdenum, cadmium, and lead among the four studied species. The element levels reported for bears and wolves represent baseline values for the Dinaric population.

Heavy metal bioaccumulation in two passerines with differing migration strategies

Various anthropogenic activities have resulted in concentration of heavy metals and contamination of surrounding environments. Historically, heavy metal contamination at the Savannah River Site (SRS) in South Carolina has resulted from accidental releases of stored waste generated from nuclear weapon production in the early 1950s. Songbirds inhabiting and using resources from these areas have the potential to bioaccumulate metals but there is limited information on metal concentration levels in areas suspected of contamination as well as uncontaminated sites. Nonlethal tissues samples from avian blood and feathers provide a reliable approach for determining the bioavailability of these pollutants (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, and Zn). The objectives of this study were to survey terrestrial heavy metal contamination at the SRS on potentially bioavailable contaminated (PBC) sites through blood and feather samples from resident Northern Cardinals (Cardinalis cardinalis) and migratory Great Crested Flycatchers (Myiarchus crinitus) and quantify sex-specific concentrations within species. Samples were collected in April to June of 2016. Cardinals had lower blood concentrations of Hg (β=-0.17, 85% CL=-0.26, -0.09) and Se (β=-0.33, 85% CL=-0.50, -0.16) than flycatchers. Cr feather concentrations were less in cardinals (β=-1.46, 85% CL=-2.44, -0.49) and all feathers of both species from reference locations had significantly less Zn (β=-67.92, 85% CL=-128.71, -7.14). Results indicate flycatchers were exposed to differing heavy metal levels during feather formation on their wintering grounds as compared to their recent exposure (through bloods samples) on their breeding grounds. Sex of individuals did not have a significant impact on bioaccumulation in either species. Overall, metal concentration levels in both species indicate minimal risk for acute toxicity; however, there is limited research on wild passerine populations with similar concentration levels. Therefore, further research on reproductive success of these birds should be explored.

Does gender influence the levels of heavy metals in liver of wild boar?

The aim of this study was to determine heavy metal reference levels for risk assessment studies. For this purpose, the levels of lead, cadmium, copper and zinc were determined in liver tissues of wild boars sampled in NW Spain. The mean values were 0.383, 0.326, 23.50 and 56.86mg/kg dried weight, respectively. In general, the levels detected were similar to or lower than the levels reported in literature. This study not only provides a useful baseline for biomonitoring the levels of the analyzed contaminants in wildlife in NW Spain, it also helps to understand the effects of gender on the levels of these elements. Similar to studies performed in other geographical regions, no significant gender-related differences could be detected. Although differences were not significant, the levels of zinc, cadmium and lead were modestly higher in males (55.78, 0.346 and 0.424mg/kg, respectively) compared to females (45.25, 0.305 and 0.341mg/kg). Our results indicate that, although gender did not significantly affect heavy metal uptake and toxicokinetics of contaminants in wild boars, these effects could vary between species, populations, organs, and elements. It is therefore essential to investigate gender-related differences for each species.

Macro- and microelements in the rat liver, kidneys, and brain tissues; sex differences and effect of blood removal by perfusion in vivo

Concentrations of macro- and microelements in animal organs indicate the animal health status and represent reference data for animal experiments. Their levels in blood and tissues could be different between sexes, and could be different with and without blood in tissues. To test these hypotheses, in adult female and male rats the concentrations of various elements were measured in whole blood, blood plasma, and tissues from blood-containing (nonperfused) and blood-free liver, kidneys, and brain (perfused in vivo with an elements-free buffer). In these samples, 6 macroelements (Na, Mg, P, S, K, Ca) and 14 microelements (Fe, Mn, Co, Cu, Zn, Se, I, As, Cd, Hg, Pb, Li, B, Sr) were determined by inductively coupled plasma mass spectrometry following nitric acid digestion. In blood and plasma, female- or male-dominant sex differences were observed for 6 and 5 elements, respectively. In nonperfused organs, sex differences were observed for 3 (liver, brain) or 9 (kidneys) elements, whereas in perfused organs, similar differences were detected for 9 elements in the liver, 5 in the kidneys, and none in the brain. In females, perfused organs had significantly lower concentrations of 4, 5, and 2, and higher concentrations of 10, 4, and 7 elements, respectively, in the liver, kidneys, and brain. In males, perfusion caused lower concentrations of 4, 7, and 2, and higher concentrations of 1, 1, and 7 elements, respectively, in the liver, kidneys, and brain. Therefore, the residual blood in organs can significantly influence tissue concentrations of various elements and their sex-dependency.

Heavy Metals in Liver and Brain of Waterfowl from the Evros Delta, Greece

The concentrations of six heavy metals (cadmium [Cd], chromium [Cr], copper [Cu], manganese [Mn], lead [Pb], and zinc [Zn]) were determined in liver and brain of nine species of waterfowl from the Evros Delta, one of the most important wetlands in Greece, to assess metal contamination and potential risk to waterfowl. Significant differences among species were found for hepatic Cr, Cu, Pb, and Zn; the highest levels of all metals were found in liver of mute swans. Cd increased significantly with age in both organs of wigeon; some differences were also observed between males and females of the same species. Feeding habits were found to significantly affect hepatic Cr, Zn, and Cu concentrations with greater concentrations found in herbivorous than omnivorous species. Several significant positive correlations between metals were detected mainly in liver samples, which were attributable either to their association to metallothioneins or to common routes of exposure of waterfowl. Hepatic and cerebral concentrations of Cd and Pb correlated positively. Given the discrepancies in the thresholds or critical levels of metals in tissues of waterfowl, our survey showed that environmental exposure to increased levels of heavy metals may threaten, at least to some degree, the populations of waterfowl wintering in the Evros Delta. In a small percentage of birds, values indicative of severe adverse effects were determined. Swans that had been found dead showed some of the highest values, whereas accumulation levels did not follow a consistent pattern among the ducks examined.

Evaluation of some factors influencing on variability in bioaccumulation of heavy metals in rodents species: Rombomys opimus and Rattus norvegicus from central Iran

In the present study, the effects of sex, age, nutritional status, and habitat use on hair and internal tissue concentrations of some trace metals (Zn, Cu, Ni, Pb and Cd) in brown rat (Rattus norvegicus) and great gerbil (Rhombomys opimus) from Aran-O-Bidgol City in Central Iran were investigated. Five sampling stations in different land-uses were selected for the study. Concentrations of Cd and Pb in liver and whole body concentration as well as concentration of Zn in hair of male rats were significantly higher than females. A significantly higher concentration was only observed for Pb in kidney of male gerbils than females. In numerous cases, age had significantly negative correlations with concentration of metals in different tissues of both species, and was only significantly (and positively) correlated with the concentration of Cd in kidney and Zn in liver of gerbils. This finding may indicate that the early neonatal age is a critical period for metals accumulation. The relationships between nutritional status and metal concentrations for both species were negative, which can be ascribed to the weight-specific metabolic rate that cause to a relatively low uptake of metals per unit of body weight. No significant differences were observed for soil metals concentrations in different sites. So, this suggests that the influence of life history, microhabitat use and foraging behavior did significantly influence on inter and intra specific variation of metals concentration in small mammals. Our observations suggest that hair cannot be used alone for monitoring exposure of metals.

Sex Differences in Human and Animal Toxicology

Sex, the states of being female or male, potentially interacts with all xenobiotic exposures, both inadvertent and deliberate, and influences their toxicokinetics (TK), toxicodynamics, and outcomes. Sex differences occur in behavior, exposure, anatomy, physiology, biochemistry, and genetics, accounting for female-male differences in responses to environmental chemicals, diet, and pharmaceuticals, including adverse drug reactions (ADRs). Often viewed as an annoying confounder, researchers have studied only one sex, adjusted for sex, or ignored it. Occupational epidemiology, the basis for understanding many toxic effects in humans, usually excluded women. Likewise, Food and Drug Administration rules excluded women of childbearing age from drug studies for many years. Aside from sex-specific organs, sex differences and sex × age interactions occur for a wide range of disease states as well as hormone-influenced conditions and drug distribution. Women have more ADRs than men; the classic sex hormone paradigm (gonadectomy and replacement) reveals significant interaction of sex and TK including absorption, distribution, metabolisms, and elimination. Studies should be designed to detect sex differences, describe the mechanisms, and interpret these in a broad social, clinical, and evolutionary context with phenomena that do not differ. Sex matters, but how much of a difference is needed to matter remains challenging.

Corticosterone levels in relation to trace element contamination along an urbanization gradient in the common blackbird (Turdus merula)

In a rapidly urbanizing world, trace element pollution may represent a threat to human health and wildlife, and it is therefore crucial to assess both exposition levels and associated effects of trace element contamination on urban vertebrates. In this study, we investigated the impact of urbanization on trace element contamination and stress physiology in a wild bird species, the common blackbird (Turdus merula), along an urbanization gradient (from rural to moderately urbanized areas). Specifically, we described the contamination levels of blackbirds by 4 non-essential (Ag, Cd, Hg, Pb) and 9 essential trace elements (As, Co, Cr, Cu, Fe, Mn, Ni, Se, Zn), and explored the putative disrupting effects of the non-essential element contamination on corticosterone levels (a hormonal proxy for environmental challenges). We found that non-essential trace element burden (Cd and Pb specifically) increased with increasing urbanization, indicating a significant trace element contamination even in medium sized cities and suburban areas. Interestingly, the increased feather non-essential trace element concentrations were also associated with elevated feather corticosterone levels, suggesting that urbanization probably constrains birds and that this effect may be mediated by trace element contamination. Future experimental studies are now required to disentangle the influence of multiple urban-related constraints on corticosterone levels and to specifically test the influence of each of these trace elements on corticosterone secretion.

Sex differences in contaminant concentrations of fish: a synthesis

A comparison of whole-fish polychlorinated biphenyl (PCB) and total mercury (Hg) concentrations in mature males with those in mature females may provide insights into sex differences in behavior, metabolism, and other physiological processes. In eight species of fish, we observed that males exceeded females in whole-fish PCB concentration by 17 to 43 %. Based on results from hypothesis testing, we concluded that these sex differences were most likely primarily driven by a higher rate of energy expenditure, stemming from higher resting metabolic rate (or standard metabolic rate (SMR)) and higher swimming activity, in males compared with females. A higher rate of energy expenditure led to a higher rate of food consumption, which, in turn, resulted in a higher rate of PCB accumulation. For two fish species, the growth dilution effect also made a substantial contribution to the sex difference in PCB concentrations, although the higher energy expenditure rate for males was still the primary driver. Hg concentration data were available for five of the eight species. For four of these five species, the ratio of PCB concentration in males to PCB concentration in females was substantially greater than the ratio of Hg concentration in males to Hg concentration in females. In sea lamprey (Petromyzon marinus), a very primitive fish, the two ratios were nearly identical. The most plausible explanation for this pattern was that certain androgens, such as testosterone and 11-ketotestosterone, enhanced Hg-elimination rate in males. In contrast, long-term elimination of PCBs is negligible for both sexes. According to this explanation, males not only ingest Hg at a higher rate than females but also eliminate Hg at a higher rate than females, in fish species other than sea lamprey. Male sea lamprey do not possess either of the above-specified androgens. These apparent sex differences in SMRs, activities, and Hg-elimination rates in teleost fishes may also apply, to some degree, to higher vertebrates including humans. Our synthesis findings will be useful in (1) developing sex-specific bioenergetics models for fish, (2) developing sex-specific risk assessment models for exposure of humans and wildlife to contaminants, and (3) refining Hg mass balance models for fish and higher vertebrates.

Concentrations of Metals in Feathers of Magpie (Pica pica) from Aran-O-Bidgol City in Central Iran

The present study aims to measure Zn, Cu, Pb and Cd concentrations in feathers of Magpies in urban areas to investigate the possibility of using Magpies to monitor metal contamination in urban areas. A total of 15 bird samples were collected in October 2013 from Aran-O-Bidgol City, in Central Iran and the concentration of metals were measured using a PerkinElmer ICP-OES. The average concentrations of Zn, Cu, Pb and Cd in the feathers were 167.16, 26.74, 9.29 and 1.583 µg/g dw, respectively. There were no significant differences in metal concentrations between various genders, ages and sites. However, the highest and lowest concentrations of non-essential elements were observed in the adult males and adult females, respectively. Significant correlations were observed between the concentrations of Cu and Zn as well as Pb and Cd. Moreover, wing length had the highest correlation with metals concentrations.

Sex-related mercury bioaccumulation in fish from the Madeira River, Amazon

Sex plays an important role in the kinetics and dynamics of methylmercury in some animals. Although fish is the main source of mercury exposure to consumers, the role of sex in fish-Hg bioaccumulation is less known. We studied total Hg (THg) concentrations in 2538 samples (males=1052, females=1486) of fish from different trophic levels (herbivorous, planctivorous, detritivorous, omnivorous, carnivorous, piscivorous); for each species we made a post hoc estimation of the minimum number of samples required to detect variance-based differences between sexes. Only five of the 41 studied species showed significant difference between sexes; but, no consistent dominant pattern of THg concentrations favored either sex. When grouped by trophic levels, overall mean difference in THg concentrations between males and females were not statistically significant. Correlation analysis showed sex-dependent THg bio-accumulation as a function of condition factor was statistically significant and negative for all trophic levels (detritivorous, herviborous, omnivorous, planctivorous, carnivorous, and piscivorous).

CONCLUSIONS

Sex is not the main driver of Hg bioaccumulation in most Amazonian fish species; however, studies have to consider the minimum number of samples required to ascertain sex effects on THg bioaccumulation. Therefore, neither the surveillance of environmental pollution nor the current food advisories based on muscle THg need to change because of fish sex.

Sex-associated differences in trace metals concentrations in and on the plumage of a common urban bird species

Urban areas encompass both favorable and stressful conditions linked with human activities and pollution. Pollutants remain of major ecological importance for synanthropic organisms living in the city. Plumage of urban birds harbour trace metals, which can result from external deposition or from internal accumulation. External and internal plumage concentrations likely differ between specific trace metals, and may further differ between males and females because of potential sex-linked differential urban use, physiology or behaviour. Here, we measured the concentrations in four trace metals (cadmium, copper, lead and zinc) in both unwashed and washed feathers of 49 male and 38 female feral pigeons (Columba livia) from Parisian agglomeration. We found that these concentrations indeed differed between unwashed and washed feathers, between males and females, and for some metals depended on the interaction between these factors. We discuss these results in the light of physiological and behavioural differences between males and females and of spatial repartition of the four trace metals in the city.

Elemental composition of two ecologically contrasting seamount fishes, the bluemouth (Helicolenus dactylopterus) and blackspot seabream (Pagellus bogaraveo)

Concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd and Pb were determined in muscle, liver and gonads of two ecologically contrasting fishes, Helicolenus dactylopterus (benthic) and Pagellus bogaraveo (benthopelagic). Elevated concentrations of As, Se and Cd found in tissues of both species appear to mirror the contribution of volcanic activity to the natural inputs of elements to Azorean waters. Results showed different element accumulation between the two species. Whereas higher concentrations were found in the liver of P. bogaraveo, elevated values were observed in the muscle of H. dactylopterus. Differences in accumulation are most likely related to metabolic rates, diet specificities and habitat. Concentrations in gonads varied up to four orders of magnitude, being higher and more variable in P. bogaraveo than H. dactylopterus. Elevated values of Cd were detected in gonads of both species despite its non-essential role on metabolic functions, presumably related to elimination.

Study on Metal Concentrations in Tissues of Mallard and Pochard from Two Major Wintering Sites in Southeastern Caspian Sea, Iran

We examined concentrations of cadmium, chromium, iron, lead and zinc in the kidney, liver, and pectoral muscle of Mallards (Anas platyrhynchos; n = 30) and Pochards (Aythya ferina; n = 30) from two important wintering sites in the southeastern Caspian Sea in the winter of 2012. Mean lead concentrations (µg g(-1) ww) in livers (2.36 ± 1.00) of Pochard and in kidneys (3.43 ± 0.91) of Mallard exceeded the exposure threshold levels in liver (1.5 µg g(-1) ww) and kidney (3 µg g(-1) ww) of waterfowl. Mean cadmium concentrations in livers (1.63 ± 0.66) of Pochards exceeded the background level of this metal in liver (1 µg g(-1) ww) of waterfowl. Chromium, iron and zinc concentrations were within the normal range as reported in other duck studies. Gender-related and inter-specific variation of metal concentrations in analyzed tissues were observed (t test, p < 0.05). Our results indicated that waterfowl using the Miankalah and Gomishan International Wetlands are being exposed to elevated concentrations of cadmium and lead.

Mercury in muscle and brain of catfish from the Madeira river, Amazon, Brazil

The central nervous system is a critical target for Hg toxicity in all living organisms. Total Hg (THg) was determined in brain and muscle samples of 165 specimens of eight species of catfish (Brachyplatystoma filamentosum; Brachyplatystoma platynemum; Brachyplatystoma rousseauxii; Brachyplatystoma vaillantii; Phractocephalus hemiliopterus; Pseudoplatystoma punctifer; Pseudoplatystoma tigrinum; Zungaro zungaro) from the Madeira River, Brazilian Amazon. Despite the narrow range of Fishbase trophic level (4.2-4.6) the median THg concentrations ranged from 0.39 to 1.99mg/kg and from 0.03 to 0.29mg/kg respectively in muscle and brain from the studied species. Overall, the median concentration for all samples analyzed was 0.93mg/kg and 0.16mg/kg respectively in muscle and brain; most samples (76%) showed muscle Hg concentrations >0.5mg/kg. There were statistically significant THg differences between sex (female>males). The correlation between THg concentrations in muscle and brain was statistically significant (r=0.9170; p<0.0001). In the studied specimens, fish total length was significantly correlated with muscle (r=0.3163; p=0.0001) and brain (r=0.3039; p=0.0003) THg; however, fish age was negatively and significantly correlated (r=-0.2991; p=0.0012) with THg in muscle but not with THg in brain (r=-0.0190; p=0.8492). Amazonian catfish accumulate high levels of Hg in muscle and brain; however, brain-THg concentrations can be predicted from muscle-THg. Muscle-Hg in catfish can be a tool to detect brain-Hg concentrations associated with environmental Hg.

Tracking the sources of polybrominated diphenyl ethers in birds: foraging in waste management facilities results in higher DecaBDE exposure in males

Differences in feeding ecology are now recognized as major determinants of inter-individual variations in contaminant profiles of free-ranging animals, but exceedingly little attention has been devoted to the role of habitat use. Marked inter-individual variations and high levels of polybrominated diphenyl ethers (PBDEs) (e.g., DecaBDE) have previously been documented in ring-billed gulls (Larus delawarensis) breeding in a colony near Montreal (QC, Canada). However, the environmental sources of these compounds, and thus the reasons causing these large inter-individual variations remain unidentified. In the present study, we used GPS-based telemetry (±5 to 10m precision) to track ring-billed gulls from this colony to reconstruct their movements at the landscape level. We related habitat use of individual gulls (n=76) to plasma concentrations (ng/g ww) and relative contributions (percentages) to Σ38PBDEs of major congeners in the internationally restricted PentaBDE and current-use DecaBDE mixtures. Male gulls that visited waste management facilities (WMFs; i.e., landfills, wastewater treatment plants and related facilities; 25% of all GPS-tracked males) exhibited greater DecaBDE (concentrations and percentages) and lower PentaBDE (percentages) relative to those that did not. In contrast, no such relationships were found in females. Moreover, in males, DecaBDE (concentrations and percentages) increased with percentages of time spent in WMFs (i.e., ~5% of total foraging time), while PentaBDE (percentages) decreased. No relationships between percentages of time spent in other habitats (i.e., urban areas, agriculture fields, and St. Lawrence River) were found in either sex. These findings suggest that animals breeding in the vicinity of WMFs as well as mobile species that only use these sites for short stopovers to forage, could be at risk of enhanced DecaBDE exposure.

No delayed behavioral and phenotypic responses to experimental early-life lead exposure in great tits (Parus major)

Early-life exposure to pollutants, such as lead, may have long-lasting consequences on health, behavior, and cognition. However, experiments on delayed effects of specific pollutants are very rare in wild animals. We experimentally exposed wild nestling great tits (Parus major) to dietary lead (high, low, or control group) in levels relevant to exposure levels of wild populations in Europe and studied delayed effects on phenotypic and behavioral traits in captivity. We also included a group of birds from a vicinity of a copper smelter, exposed to a mixture of toxic metals and altered food supply during development. This experimental setup allowed us to compare the strength of direct (exposure to lead per se) and indirect (pollution-related changes in diet) effects of pollutants. Our experimental lead treatment significantly increased lead levels in bone and feces compared with controls. However, we found no carry-over effect of early-life dietary lead on morphology, plumage coloration, or heat shock proteins. Treatment did not affect activity, exploration, neophobia, or success in learning and spatial memory task. We conclude that with the exposure levels and relatively short exposure period used, delayed effects on the measured traits were not found. However, it is important to further study other types of behavioral traits and ultimately fitness effects.

Experimental manipulation of dietary lead levels in great tit nestlings: limited effects on growth, physiology and survival

We manipulated dietary lead (Pb) levels of nestlings in wild populations of the great tit (Parus major L) to find out if environmentally relevant Pb levels would affect some physiological biomarkers (haematocrit [HT], fecal corticosterone metabolites [CORT], heat shock proteins [HSPs], erythrocyte delta-aminolevulinic acid dehydratase activity [ALAd]), growth (body mass, wing length), phenotype (plumage coloration) or survival of nestlings. The responses to three experimental manipulation (control, low and high: 0, 1 and 4 μg/g body mass/day) are compared with those in a P. major population breeding in the vicinity of a heavy metal source, a copper smelter. Our Pb supplementation was successful in raising the fecal concentrations to the levels found in polluted environments (high: 8.0 μg/g d.w.). Despite relatively high range of exposure levels we found only few effects on growth rates or physiology. The lack of blood ALAd inhibition suggests that the circulating Pb levels were generally below the toxic level despite that marked accumulation of Pb in femur (high: 27.8 μg/g d.w.) was observed. Instead, birds in the metal polluted environment around the smelter showed decreased growth rates, lower HT, higher CORT, less colorful plumage and lower survival probabilities than any of the Pb treated groups. These effects are likely related to decreased food quality/quantity for these insectivorous birds at the smelter site. In general, the responses of nestlings to metal exposure and/or associated resource limitation were not gender specific. One of the stress proteins (HSP60), however, was more strongly induced in Pb exposed males and further studies are needed to explore if this was due to higher accumulation of Pb or higher sensitivity of males. In all, our results emphasize the importance of secondary pollution effects (e.g. via food chain disruption) on reproductive output of birds.

Noninvasive heavy metal pollution assessment by means of Iberian wolf (Canis lupus signatus) hair from Galicia (NW Spain): a comparison with invasive samples

The current study represents the first investigation of the suitability of wolf hair as indicator tissue for metal exposure and accumulation within NW Spanish ecosystems. Dead animals, which were not specifically killed for these purposes, were necropsied, and further toxicological analyses were performed in order to establish the heavy metal content (Pb, Cd, and Zn) in liver, kidney, and hair, by means of inductively coupled plasma optical emission spectrometry. Two different factors, gender and age, were considered in order to determine their influence on heavy metal accumulation. Mean liver, kidney and hair concentrations of both toxic element, Cd (0.528, 2.692, and 0.026 ppm) and Pb (4.108, 0.031, and 0.196 ppm) considered on a dry weight basis, were situated below the established as acute toxicity levels for mammals. The highest concentrations were quantified for Zn, with means ranging from a maximum in hair samples (150.9 ppm) to a minimum in kidney samples (25.81 ppm). When the variable of gender and age were considered, female and adult wolves had higher concentrations of Cd in all the considered organs, although differences were only statistically significant for kidney. Neither the sex nor the age had a significant effect on Pb and Zn concentrations. A significant positive correlation (p < 0.05) was identified between hair and liver Pb concentrations, as well as between hair and kidney Cd concentrations, thus suggesting the interest of the noninvasive sample for future ecotoxicological biomonitoring studies.

Assessment of metal concentrations in commercially important fish species in Black Sea

In the present study, concentrations of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) were measured in the muscle, gill, and gonads of the pelagic fish species Trachurus mediterraneus, Engraulis encrasicolus ponticus, and Sprattus sprattus that are important both commercially and for the ecosystems in the Black Sea. The samples were collected during 2011. The metals were determined using inductively coupled plasma mass spectrometry (ICP-MS) following an acid digestion. The highest concentrations of As, Cd, Co, Cr, Cu, Pb, and Zn were found in E. encrasicolus ponticus, whereas the greatest concentrations of Ni were found in T. mediterraneus and Mn in S. sprattus. Results showed that average metal concentrations in the tissues of T. mediterraneus, E. encrasicolus ponticus, and S. sprattus decreased in the order gill > gonad > muscle, gonad > gill > muscle, and gill > gonad > muscle, respectively, for the three species. When metal concentrations of fish tissues were compared between fish gender, there were only statistical differences in the gonads of the studied fish species (p < 0.05). The present study demonstrated that the metals have different correlations with condition factor (CF) and gonadosomatic index (GSI) of the fish species. Cr showed statistically important positive correlation to the GSI in male T. mediterraneus. Co showed statistically important positive correlation to CF in female E. encrasicolus ponticus, and also Co and Cd showed correlation to CF in male T. mediterraneus. Cd concentrations in the muscle tissues of the fish species were above the maximum acceptable concentration for human consumption.