Monitoring urban heavy metal pollution using the House Sparrow (Passer domesticus)

House Sparrows as Sentinels of Childhood Lead Exposure

Our understanding of connections between human and animal health has advanced substantially since the canary was introduced as a sentinel of toxic conditions in coal mines. Nonetheless, the development of wildlife sentinels for monitoring human exposure to toxins has been limited. Here, we capitalized on a three-decade long child blood lead monitoring program to demonstrate that the globally ubiquitous and human commensal house sparrow (Passer domesticus) can be used as a sentinel of human health risks in urban environments impacted by lead mining. We showed that sparrows are a viable proxy for the measurement of blood lead levels in children at a neighborhood scale (0.28 km2). In support of the generalizability of this approach, the blood lead relationship established in our focal mining city enabled us to accurately predict elevated blood lead levels in children from another mining city using only sparrows from the second location. Using lead concentrations and lead isotopic compositions from environmental and biological matrices, we identified shared sources and pathways of lead exposure in sparrows and children, with strong links to contamination from local mining emissions. Our findings showed how human commensal species can be used to identify and predict human health risks over time and space.

Distribution of rare earth elements (REEs) in the feathers of gentoo penguins (Pygoscelis papua) from different geographical locations of the Antarctic peninsula area

Antarctica is the most remote and coldest regions of the planet, but the presence of REEs there has received little attention. This study assessed REE-contents in the feathers of adult gentoo penguins from Ardley Island, Kopaitic Island and Base O'Higgins. Field work was accomplished during 2011 (austral summer), and determination of elements was performed with ICP-MS. In general, REE-levels showed descending relations as follows: Ce > La > Y > Nd > Sc > Pr > Gd > Sm > Dy >Er > Yb > Eu > Ho > Tb > Tm > Lu. The data showed an increase of the levels of REEs from the lower part of the feather to the tip. This finding seems to be spatially dependent, but geochemical, anthropogenic conditions, feeding habits, sex, or even health status of birds should also be considered. It is a subject that requires deeper attention in future studies.

Exposure to Sublethal Concentrations of Lead (Pb) Affects Ecologically Relevant Behaviors in House Sparrows (Passer domesticus)

Global contamination of environments with lead (Pb) poses threats to many ecosystems and populations. While exposure to Pb is toxic at high concentrations, recent literature has shown that lower concentrations can also cause sublethal, deleterious effects. However, there remains relatively little causal investigation of how exposure to lower concentrations of environmental Pb affects ecologically important behaviors. Behaviors often represent first-line responses of an organism and its internal physiological, molecular, and genetic responses to a changing environment. Hence, better understanding how behaviors are influenced by pollutants such as Pb generates crucial information on how species are coping with the effects of pollution more broadly. To better understand the effects of sublethal Pb on behavior, we chronically exposed adult wild-caught, captive house sparrows (Passer domesticus) to Pb-exposed drinking water and quantified a suite of behavioral outcomes: takeoff flight performance, activity in a novel environment, and in-hand struggling and breathing rate while being handled by an experimenter. Compared to controls (un-exposed drinking water), sparrows exposed to environmentally relevant concentrations of Pb exhibited decreases in takeoff flight performance and reduced movements in a novel environment following 9-10 weeks of exposure. We interpret this suite of results to be consistent with Pb influencing fundamental neuro-muscular abilities, making it more difficult for exposed birds to mount faster movements and activities. It is likely that suppression of takeoff flight and reduced movements would increase the predation risk of similar birds in the wild; hence, we also conclude that the effects we observed could influence fitness outcomes for individuals and populations altering ecological interactions within more naturalistic settings.

Stochastic processes shape the functional and phylogenetic structure of bird assemblages at the mine area in southwest China

Understanding the mechanisms of community assembly is a key question in ecology. Metal pollution may result in significant changes in bird community structure and diversity, with implications for ecosystem processes and function. However, the relative importance of these processes in shaping the bird community at the polluted area is still not clear. Here, we explored bird species richness, functional, and phylogenetic diversity, and the assembly processes of community at the mine region of southwest China. Our results showed that the 3 dimensions of diversity at the mine area were lower than that at the reference sites. In the community assembly, the result was 0 < NRI/ NFRI < 1.96, which indicated deterministic processes (environmental filtering) might drive community clustering. The results of the neutral community model, and normalized stochasticity ratio, showed the dominant role of stochastic processes in shaping the bird community assembly. We further quantified the community-level habitat niche breadth (Bcom), and we found that there was no difference in Bcom-value between the mine area and reference sites. This indicates that the bird communities at the mine area and 3 reference sites were not subjected to extreme environmental selection (same or different resource allocation) to form a highly specialized niche. These findings provide insights into the distribution patterns and dominant ecological processes of bird communities under metal exposure, and extend the knowledge in community assembly mechanisms of bird communities living in the mine area.

Can blood morphology, oxidative stress, and cholinesterase activity determine health status of pigeon Columba livia f. urbana?

Environmental studies in Northern Poland are example of the functioning of ecophysiological relationships under anthropogenic impact. The aim of our studies was to investigate sex-dependent effects on the alterations in the concentration of chemical elements in soil samples collected from habitats of feral pigeon Columba livia f. urbana from Northern Poland, as well as feathers, biomarkers of oxidative stress, antioxidant defense, and total cholinesterase activity in tissues (liver, kidney, brain). Concentration of Si, Zn, and Pb in feathers of pigeons was significant. The levels of Si and Zn were higher in feathers of females from non-polluted, while higher Pb levels were found only in females from polluted areas (p = 0.000). This was confirmed by MANOVA of biomarkers of antioxidant defense, elements concentration, and revealing the order of effects: tissue type > environment > sex. Erythrocytes of males living in polluted areas were more fragile to hemolytic agents resulting in a higher percentage of hemolyzed erythrocytes. The effects of polluted environment on the level of carbonyl derivatives of oxidatively modified proteins compared to the effects of sex were more pronounced in the case of kidney (p = 0.000) and hepatic tissues (p = 0.000). Polluted areas were associated with significant increase in SOD activity in the brain and hepatic tissues of pigeons (p = 0.000). Health status of feral pigeons is significantly different in conditions of environmental destabilization.

Lead exposure is related to higher infection rate with the gapeworm in Norwegian house sparrows (Passer domesticus)

Anthropogenic pollution is identified as an important threat to bird and other wildlife populations. Many metals and toxic elements, along with poly- and perfluoroalkyl substances (PFASs) are known to induce immunomodulation and have previously been linked to increased pathogen prevalence and infectious disease severity. In this study, the house sparrow (Passer domesticus) was investigated at the coast of Helgeland in northern Norway. This population is commonly infected with the parasitic nematode "gapeworm" (Syngamus trachea), with a prevalence of 40-60 % during summer months. Gapeworm induces severe respiratory disease in birds and has been previously demonstrated to decrease survival and reproductive success in wild house sparrows. The aim of this study was to investigate whether a higher exposure to pollution with PFASs, metals and other elements influences gapeworm infection in wild house sparrows. We conducted PFASs and elemental analysis on whole blood from 52 house sparrows from Helgeland, including analyses of highly toxic metals such as lead (Pb), mercury (Hg) and arsenic (As). In addition, we studied gapeworm infection load by counting the parasite eggs in faeces from each individual. We also studied the expression of microRNA 155 (miR155) as a key regulator in the immune system. Elevated blood concentrations of Pb were found to be associated with an increased prevalence of gapeworm infection in the house sparrow. The expression of miR155 in the plasma of the house sparrow was only weakly associated with Pb. In contrast, we found relatively low PFASs concentrations in the house sparrow blood (∑ PFASs 0.00048-354 μg/L) and PFASs were not associated to miR155 nor infection rate. The current study highlights the potential threat posed by Pb as an immunotoxic pollutant in small songbirds.

Elevated lead (Pb) in urban European starling (Sturnus vulgaris) feathers is not correlated to physiology or behavior

Urbanization is rapidly changing the environment and creating new challenges in the lives of animals across the globe. Anthropogenic contaminants-like heavy metals-can persist within the environment for prolonged periods of time and present a widespread problem for those living near contaminated areas. Lead (Pb) was a commonly used heavy metal that continues to threaten the health of all organisms despite being phased out, especially in urban areas where historical use was more common. In this study, a common urban-adapter, the European starling (Sturnus vulgaris), was trapped to explore whether feather Pb burden is greater in birds from urban habitats than rural habitats, as well as whether Pb burdens were correlated with behavior, physiology, and feather development. Across four sites (two rural and two urban), soil Pb concentrations were measured and 197 free-living starlings were captured to measure feather Pb concentrations. Using linear mixed models, this study found that urban starling nestlings had elevated feather Pb burdens compared to rural nestlings. In contrast, there was no correlation between Pb and urbanization in adult birds whose exposure to Pb may reflect a larger spatial range compared to nestlings. For both nestlings and adults, feather Pb was uncorrelated to corticosterone, testosterone, aggressive behavior, or feather growth rates. These findings suggest that starlings may be a useful biomonitoring tool to detect Pb in the local environment, however, the age and spatial range of birds is a critical consideration in applying this tool. Further work is needed to understand the intricate relationship between heavy metals, behavior, morphological development, and physiology in free-living organisms.

Potentially toxic elements in different tissues of great cormorant (Phalacrocorax carbo) at a wetland area

Concentrations of 4 potentially toxic elements (As, Cd, Hg, Pb) were investigated in the feather, liver, kidney, and bone of great cormorants (Phalacrocorax carbo). The tissue samples were taken at the Central Tisza - Jászság Nature Conservation Area in Hungary. They were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The goal of the investigation was to analyse the metal burden of the above-mentioned elements in the various tissues of these wild birds and to provide important information for monitoring the environmental pollution.Amongst the examined potentially toxic elements no statistical gender difference was observed, so the data were not separated based on them during the statistical analysis. The concentration of mercury was the highest in the feather, followed by the liver, kidney, and bone. The lead was detected in the feather with the highest level followed by the kidney, liver, and bone. The cadmium was determined in all investigated tissues with the next descending order: kidney > bone > liver > feather. Highest arsenic concentration was measured in the feather, followed by liver, kidney, and bone with the same concentration.The detected concentrations of the investigated potentially toxic elements in different tissues of great cormorants (feathers, liver, kidney, bone) means that the living area of this birds is not highly contaminated to induce health problems or toxic signs, or even other undesirable effect in the animals.

Chronic exposure to tebuconazole alters thyroid hormones and plumage quality in house sparrows (Passer domesticus)

Triazoles belong to a family of fungicides that are ubiquitous in agroecosystems due to their widespread use in crops. Despite their efficiency in controlling fungal diseases, triazoles are also suspected to affect non-target vertebrate species through the disruption of key physiological mechanisms. Most studies so far have focused on aquatic animal models, and the potential impact of triazoles on terrestrial vertebrates has been overlooked despite their relevance as sentinel species of contaminated agroecosystems. Here, we examined the impact of tebuconazole on the thyroid endocrine axis, associated phenotypic traits (plumage quality and body condition) and sperm quality in wild-caught house sparrows (Passer domesticus). We experimentally exposed house sparrows to realistic concentrations of tebuconazole under controlled conditions and tested the impact of this exposure on the levels of thyroid hormones (T3 and T4), feather quality (size and density), body condition and sperm morphology. We found that exposure to tebuconazole caused a significant decrease in T4 levels, suggesting that this azole affects the thyroid endocrine axis, although T3 levels did not differ between control and exposed sparrows. Importantly, we also found that exposed females had an altered plumage structure (larger but less dense feathers) relative to control females. The impact of tebuconazole on body condition was dependent on the duration of exposure and the sex of individuals. Finally, we did not show any effect of exposure to tebuconazole on sperm morphology. Our study demonstrates for the first time that exposure to tebuconazole can alter the thyroid axis of wild birds, impact their plumage quality and potentially affect their body condition. Further endocrine and transcriptomic studies are now needed not only to understand the underlying mechanistic effects of tebuconazole on these variables, but also to further investigate their ultimate consequences on performance (i.e. reproduction and survival).

The screening method for use of wild pheasant feathers in the monitoring of environmental pollution with heavy metals

It has been shown that some species of birds, especially herbivorous and territorial ones, are more sensitive to the effects of toxic substances compared to mammals. This allows for taking integrated actions in the area of environmental protection and monitoring in a holistic sense (at various trophic levels). Therefore, this study aimed to assess the possibility of using pheasant feathers (Phasianus colchicus) as a potential bioindicator ofenvironmental contamination, and thus to determine the concentration of heavy metals (lead-Pb, arsenic-As, cadmium-Cd, chromium-Cr, nickel-Ni, and zinc-Zn) in the analyzed tissue of animals inhabiting the forest districts of the Lubartów, Tomaszów, Skierniewice, and Ostrowiec Świętokrzyski areas. The chemical analysis used to determine the concentration of toxic elements in pheasant feathers was carried out by inductively coupled plasma mass spectrometry. The highest concentrations of Cr and Zn were found in birds from the Lubartów Forest District (1.93 mg/kg and 120.63 mg/kg, respectively), As and Ni in the Tomaszów Forest District (0.55 mg/kg and 1.60 mg/kg, respectively), Cd in the Lubartów Forest District and Skierniewice (0.04 mg/kg), and Pb in the Skierniewice Forest Distict (6.79 mg/kg). The observed results were strongly related to soil contamination and urbanization index, as key environmental factors which significantly determine the metal content in pheasant feathers. Therefore, proposed non-invasive measurements of the elemental composition of feathers of birds living in specific areas may be an important indicator of environmental pollution in relation to the high impact of anthropopressure.

Evaluation of lead exposition length on the liver and intestinal histoarchitecture of eared dove (Zenaida auriculata)

Lead (Pb) is a metal that can produces irreversible damage in living organisms. Some studies had reported that Pb produces histophysiological alterations in the digestive system (mainly liver) of birds; however, the effect of this metal on small intestine has not been fully examined. Additionally, little information is available on Pb disturbances in native birds of South America. The present study aimed to evaluate the effect of different Pb exposure times on blood δ-aminolevulinic acid dehydratase (δ-ALAD) activity and on the histological and morphometric characteristics of the digestive system (liver and proximal intestine) of eared doves (Zenaida auriculata). A decrease of the blood δ-ALAD activity, dilatation of blood vessels and leukocyte infiltrates in intestinal submucosa and muscular layers, and reduction of the enterocyte nuclear diameter and Lieberkühn crypts area were observed. In liver were noted steatosis, proliferation of bile ducts, dilated sinusoids, leukocyte infiltrates, and melanomacrophage centers. The portal tract area and the thickness of the portal vein wall were increased. In conclusion, the results showed that Pb produces histological and morphometric alterations on the liver and small intestine according to the exposure time, which should be considered when the dangerousness of environmental pollutants is evaluated in wild animals.

Does environmental pollution affect male reproductive system in naturally exposed vertebrates? A systematic review

Due to environmental contamination, the environment constantly receives pollutants from various anthropic actions. These pollutants put ecological health at risk due to contamination and accumulation in living organisms, including wild animals and humans. Exposure can cause physiological, morphological, and behavioral changes in living beings. In this context, laboratory studies have frequently investigated how environmental contaminants affect the male reproductive system and gametes. However, few studies have examined how these contaminants affect male reproduction in naturally exposed animals. To better understand this topic, we conducted a systematic review of the effects of exposing male vertebrate animals to polluted environments on their reproductive functions. After an extensive search using the PubMed/MEDLINE, Scopus, and Web of Science databases, 39 studies met our inclusion criteria and were eligible for this review. This study showed that reproductive damages were frequent in fishes, amphibians, reptiles, birds, and mammals exposed to contaminated environments. Wild animals are exposed mainly to endocrine-disrupting compounds (EDCs), toxic metals, and radiation. Exposure to pollutants causes a reduction in androgen levels, impaired spermatogenesis, morphological damage to reproductive organs, and decreased sperm quality, leading to reduced fertility and population decline. Although several species have been studied, the number of studies is limited for some groups of vertebrates. Wildlife has proven valuable to our understanding of the potential effects of environmental contaminants on human and ecosystem health. Thus, some recommendations for future investigations are provided. This review also creates a baseline for the understanding state of the art in reproductive toxicology studies.

Physiological status of House Sparrows (Passer domesticus) along an ozone pollution gradient

Mexico City is one of the most polluted cities in the world, and one in which air contamination is considered a public health threat. Numerous studies have related high concentrations of particulate matter and ozone to several respiratory and cardiovascular diseases and a higher human mortality risk. However, almost all of those studies have focused on human health outcomes, and the effects of anthropogenic air pollution on wildlife species is still poorly understood. In this study, we investigated the impacts of air pollution in the Mexico City Metropolitan Area (MCMA) on house sparrows (Passer domesticus). We assessed two physiological responses commonly used as biomarkers: stress response (the corticosterone concentration in feathers), and constitutive innate immune response (the concentration of both natural antibodies and lytic complement proteins), which are non-invasive techniques. We found a negative relationship between the ozone concentration and the natural antibodies response (p = 0.003). However, no relationship was found between the ozone concentration and the stress response or the complement system activity (p > 0.05). These results suggest that ozone concentrations in air pollution within MCMA may constrain the natural antibody response in the immune system of house sparrows. Our study shows, for the first time, the potential impact of ozone pollution on a wild species in the MCMA presenting the Nabs activity and the house sparrow as suitable indicators to assess the effect of air contamination on the songbirds.

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.

Increased lead and glucocorticoid concentrations reduce reproductive success in house sparrows along an urban gradient

Urbanization is increasing at a rapid pace globally. Understanding the links among environmental characteristics, phenotypes, and fitness enables researchers to predict the impact of changing landscapes on individuals and populations. Although avian reproductive output is typically lower in urban compared with natural areas, the underlying reasons for this discrepancy may lie at the intersection of abiotic and biotic environmental and individual differences. Recent advances in urban ecology highlight the effect of heavy metal contamination on stress physiology. As high levels of glucocorticoid hormones decrease parental investment, these hormones might be the link to decreased reproductive success in areas of high environmental pollution. In this study, we aimed to identify which abiotic stressors are linked to avian reproductive output in urban areas and whether this link is mediated by individual hormone levels. We used fine-scaled estimates (2 m2 spatial resolution) of nighttime light, noise, and urban density to assess their impacts on the physiological condition of adult house sparrows (Passer domesticus). We measured circulating levels of lead and glucocorticoid concentrations in 40 breeding pairs of free-living house sparrows and related these physiological traits to reproductive success. Using structural equation modeling, we found that increased urban density levels linked directly to increased plasma corticosterone and lead concentrations that subsequently led to decreased fledgling mass. Sparrows with increased lead concentrations in plasma also had higher corticosterone levels. Although urban areas may be attractive due to decreased natural predators and available nesting sites, they may act as ecological traps that increase physiological damage and decrease fitness. To illustrate, avian development is strongly explained by parental corticosterone levels, which vary significantly in response to urban density and lead pollution. With fine-scale ecological mapping for a species with small home ranges, we demonstrated the presence and impacts of urban stressors in a small city with high human densities.

Blood lead concentration in an urban parrot: Nestling Kaka (Nestor meridionalis) demonstrate evidence of exposure to lead via eggs and parental feeding

Lead is a persistent, highly toxic heavy metal known to affect physiological function and survival in birds. Nestlings are particularly at risk as exposure during critical stages of development can result in life-long deficits. Urban environments are increasingly associated with high levels of contamination and lead exposure at the urban-wildlife interface can have significant population health effects on wildlife. Wellington has an established population of Kaka (Nestor meridionalis) and provides the ideal opportunity to study the risks of lead exposure in an urban context. We sampled 139 nestlings over two breeding seasons (2015/16 and 2016/17) and examined concentrations of lead in blood samples. Nestlings were subjected to a clinical and neurological examination. Lead concentrations of egg shells were measured to evaluate maternal transfer of lead to nestlings. Overall, 36.7 % of nestlings showed evidence of lead exposure based on blood lead concentrations, ranging from <3.3μg/dL to 42.9μg/dL, with no detectable clinical signs of toxicity. The pattern of exposure in the majority of nestlings is indicative of exposure from hatch via eggshells and also direct parental feeding of lead following hatch. Lead concentrations in this cohort of Kaka have the potential to contribute to morbidity and mortality in this species. The lack of measurable neurological or physiological deficits associated with lead exposure is suggestive of an innate tolerance to these concentrations of lead in this population. However, the well-described subclinical and persistent effects of lead suggests a need for continued monitoring of this toxicant and its effects on Kaka behaviour and neurodevelopment.

Multiple trace elements exposure of Grey-cheeked Fulvettas Alcippe morrisonia, a nuclear member in bird mixed-species flocks, and implications for bioindicator

Birds are vulnerable to metal pollution, which can serve as indicators of environmental safety monitoring. In this study, we evaluated three non-essential (Pb, Cd, and As) and two essential (Cu and Zn) trace elements of living (only feathers) and deceased (feathers and tissues) Grey-cheeked Fulvetta (Alcippe morrisonia) at a highly polluted mine tailings and a reference site. Five metal concentrations in the feathers of living Grey-cheeked Fulvettas were higher at the mine site. Among these, the levels of Cd and Pb in most feathers exceeded the threshold, resulting in an ecotoxicological concern. The correlation analysis suggested that feathers from Grey-cheeked Fulvettas might be useful bioindicators for local metal contamination assessment. The toxicological effects of trace metals on Grey-cheeked Fulvetta might affect its leadership ability. Therefore, understanding the effects of metal pollution on Grey-cheeked Fulvetta would show important practical implications for the conservation of bird communities.

Does environmental metal pollution affect bird morphometry? A case study on the tree sparrow Passer montanus

Morphological characteristics are the leading indicators of the health status of birds. To explore the effects of heavy metals on bird morphometry in natural populations, tree sparrows (Passer montanus) were studied in a polluted site [Baiyin (BY)] and a relatively unpolluted site [Liujiaxia (LJX)]. This study aimed to examine whether morphological variables, the fluctuating asymmetry (FA) of the wing, tarsus, and toe length, were associated with heavy metals (Cu, Zn, Pb, and Cd) and Ca levels in different tissues and feces of adults and nestlings. Results showed that adults collected from BY contained relatively higher heavy metal concentrations and lower Ca concentrations in different tissues than those from LJX. Smaller body sizes and higher FA levels of adults and nestlings were found in BY than in LJX. Although higher heavy metal concentrations in some tissues were associated with smaller morphological characteristics of adults, the effects were not obvious in nestlings. The most correlated heavy metal with as many characteristics was heavy metal in primary feather in both sites, and the most affected characteristic was body mass in BY. The FA values of adults and nestlings in BY were positively affected by heavy metal concentrations in different tissues and feces. The growth rate of wing and tarsus length of nestlings in BY were negatively affected by the FA values of wing and tarsus length, respectively. Taken together, environmental metal pollution might affect the morphological characteristics of tree sparrows. These findings suggest that the morphological characteristics of tree sparrows, especially FA, can be used as indicators of metal pollution, underscoring the importance of measuring morphological characteristics in avian ecotoxicology field studies.

Socio-ecological drivers of multiple zoonotic hazards in highly urbanized cities

The ongoing COVID-19 pandemic is a stark reminder of the devastating consequences of pathogen spillover from wildlife to human hosts, particularly in densely populated urban centers. Prevention of future zoonotic disease is contingent on informed surveillance for known and novel threats across diverse human-wildlife interfaces. Cities are a key venue for potential spillover events because of the presence of zoonotic pathogens transmitted by hosts and vectors living in close proximity to dense human settlements. Effectively identifying and managing zoonotic hazards requires understanding the socio-ecological processes driving hazard distribution and pathogen prevalence in dynamic and heterogeneous urban landscapes. Despite increasing awareness of the human health impacts of zoonotic hazards, the integration of an eco-epidemiological perspective into public health management plans remains limited. Here we discuss how landscape patterns, abiotic conditions, and biotic interactions influence zoonotic hazards across highly urbanized cities (HUCs) in temperate climates to promote their efficient and effective management by a multi-sectoral coalition of public health stakeholders. We describe how to interpret both direct and indirect ecological processes, incorporate spatial scale, and evaluate networks of connectivity specific to different zoonotic hazards to promote biologically-informed and targeted decision-making. Using New York City, USA as a case study, we identify major zoonotic threats, apply knowledge of relevant ecological factors, and highlight opportunities and challenges for research and intervention. We aim to broaden the toolbox of urban public health stakeholders by providing ecologically-informed, practical guidance for the evaluation and management of zoonotic hazards.

Heavy metals in liver, kidney, brain, and muscle slender-billed gull (Chroicocephalus genei) from south-eastern Iran

The concentrations of four heavy metals nickel (Ni), cadmium (Cd), lead (Pb), and zinc (Zn) were determined in liver, kidney, muscle, and brain tissues of 40 slender-billed gulls (Chroicocephalus genei) from the Chahnimeh water reservoirs of Sistan and the Oman Sea coast of Iran. There were significant differences between Ni, Cd, Pb, and Zn concentrations observed in the liver and brains of birds from the Oman Sea coast than in the liver and brains of gulls from the Chahnimeh water reservoirs (P < 0.05). Higher levels of Pb, Cd, and Zn were found in the brain and liver of gulls than in the kidney and muscles tissues. There were significant gender differences in heavy metals in liver and brain tissue. In gulls from the coast of Oman Sea, all four elements (Cd, Pb, Ni, and Zn) were positively correlated with levels in all organs, and except for muscle, the elements were positively correlated with the other elements in the other tissues (except Ni in the brain). Thus, the pathways and sources of entry for the elements are similar, and the pathways for accumulation of these elements, and the reactions of different organs of the body to these elements, are very similar. Also, 40% of gulls in Oman Sea coast had levels of lead in the brain (>5 μg g^{-1 -1} d.w) that were above the adverse effect levels, Ni concentrations in the liver of slender-billed gull in Oman Sea coast (100 %) and Chahnimeh water reservoirs (90 %) were above toxic levels (> 3 μg g^-1 d.w), and 80% of Ni concentration in kidneys in gulls from the Oman Sea coast and Chahnimeh water reservoirs were higher than the toxicity levels (> 10 μg g^-1 d.w).

Measurement of metal concentrations in feathers of bird-vehicle collisions, Sabzevar, Iran

The purpose of the present study is to compare the concentrations of lead, copper, and zinc in feathers of birds struck in collisions with vehicles. Two main assumptions were investigated: that there is a significant difference between species with different diets and that large and old species have higher concentrations of lead than small and young species because of their longer life span and longer exposure time to pollutants. Mean concentrations were obtained for lead 0.122, 0.006, 0.007, 0.010, and 0.014, for copper 0.718, 0.783, 0.530, 0.853, and 0.793, and for zinc 0.891, 0.940, 0.787, 0.932, and 1.003 in house sparrow (Passer domesticus), tree sparrow (Passer montanus), European roller (Coracias garrulus), Little bittern (Ixobrychus minutus), and Levant sparrowhawk (Accipiter brevipes), respectively. The results showed that there were no significant differences in the concentrations of the studied elements between species with different diets and as well as between large and small size or juveniles and adults; thus, the two hypotheses were rejected. The concentrations of the studied elements were lower than the "negative effects" threshold values suggested by previous studies; thus, they are not likely to pose a serious threat to the selected species. However, it is important to include not only other non-essential elements in future studies but also larger sample sizes. It is also noteworthy that this is the first study to determine the concentration of metals in two of the species, Coracias garrulous and Accipiter brevipes.

Ten Bird Species, Six Guilds, Three Habitats, and 59 Chlorinated and Brominated POPs: What do 64 Eggs from the Largest Economic Hub of Southern Africa tell us?

There is little information on how POPs in eggs of different terrestrial, wetland, and aquatic birds share a large urban and rural landscape relate. We collected and analysed 64 eggs belonging to ten species of six feeding guilds, and compared organic chlorinated pesticide (OCP), polychlorinated biphenyl (PCB), and brominated flame retardants (BFR) residue concentrations and compositions. The eggs were collected in the Gauteng and the northern part of the Free Sate provinces of South Africa, one of the largest economic hubs in Africa. White-breasted Cormorant and African Darter eggs (at the highest trophic level as large aquatic predators) had the highest ΣOCP and ΣPCB concentrations, and Cape Sparrow and Southern Masked Weaver (granivores) eggs had the lowest concentrations, corresponding to the lowest trophic level in our collection. The highest percentage p,p'-DDT were in eggs of the terrestrial insectivore Crowned Lapwing (24%) and the scavenging African Sacred Ibis (17%), and the lowest in African Darter (1.0%) and White-breasted Cormorant (0.9%) eggs, suggesting that recency of DDT releases in a region cannot be gauged by this metric. African Sacred Ibis and Southern Masked Weaver eggs had the highest ΣBFR concentrations, with Crowned Lapwing, Cattle Egret, and White-breasted Cormorant eggs the least. Based on feeding guilds, the mean ΣPOP concentrations increased from granivore, aquatic omnivore, scavenger, terrestrial insectivore, small aquatic predator, to large aquatic predator. Mean ΣPOP concentrations in eggs increased from terrestrial, to wetland, to aquatic habitat birds. Interesting patterns were observed with multivariate analyses. There were no significant regressions between egg size and any summed POP classes. ΣBFR concentrations were not correlated with ΣOCPs or ΣPCBs. Eggshell thinning of African Darter eggs was associated with p,p'-DDE and ΣPCB suggesting risk. Other metrics also suggest risk. Therefore, different species of terrestrial and aquatic birds from the same area acquire and deposit POPs in different proportions and quantities in their eggs. Trophic levels and habitat explain the overall patterns, but detailed differences were found, some of which we are unable to explain. Based on POPs residues in terrestrial, wetland, and aquatic bird eggs, different POPs classes behave differently in a shared large inland industrial area, complicating deductions about POPs and associated risks based on one or few species.

Evaluation of homing pigeon feather tissue as a biomonitor of environmental metal concentrations in China

Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment, and homing pigeons have been proposed as a biomonitor of atmospheric pollution. We evaluated metal concentrations in homing pigeon feather tissue as a biomonitoring tool. We measured cadmium, lead, and mercury concentrations in feathers collected from 5-6-yo homing pigeons from Guangzhou, Beijing, and Harbin, China during 2011, and feathers of 1, 5, and 10-yo homing pigeons collected from Guangzhou, Beijing, and Harbin, China during 2015-16. We compared metal concentrations in feathers between sexes and among ages and evaluated spatio-temporal differences. Correlations between feather metal concentrations and previously evaluated kidney and liver metal concentrations are reported. There were no significant differences in feather metal concentrations between male and female pigeons or among 1, 5, and 10-yo pigeons. Cadmium, lead, and mercury concentrations in feathers of 1-yo pigeons were significantly correlated with concentrations in liver and kidney tissues, although the correlations were not consistent. Spatio-temporal differences in feather metal concentrations suggest the usefulness of feathers in identifying areas of concern and remedial effectiveness. Homing pigeon feather metal concentrations appear to be useful as a screening biomonitoring tool.

Heavy metal effects on bird morphometry: A case study on the house sparrow Passer domesticus

We examined some possible effects of heavy metal accumulations on bird morphometry. House sparrows Passer domesticus were caught in unpolluted and polluted areas having a thermal power plant, in Turkey. Fifteen different morphometric characters were compared with the heavy metal accumulations of Cu, Co, Zn, Mn, Ni, and Cr in samples from muscle, kidney, and liver. We found positive or negative correlations between some heavy metal accumulations in some tissues and the length of some morphometric characters of sparrows (p < 0.01). The most correlated heavy metal with as many characters was Zn in muscle and liver, followed by Cu in liver and Cu in muscle. We found mainly negative coefficient values of some heavy metal bioaccumulation for morphometry using stepwise linear regression analysis. Negative coefficient values of Zn accumulation in muscle and the liver for body mass and feathers were found (p < 0.01). Length of bill and claws were affected by the bioaccumulation; the positive coefficient values of Zn in the muscle and the liver and negative coefficient values of Cu in the kidney for the length of the bill, positive coefficient value of Cu in muscle and the negative coefficient value of Mn in the kidney for length of the claws were found respectively (p < 0.01). The heavy metal accumulations in the tissues were found to affect morphometric characters' length. The effects of heavy metal accumulations in tissues should be considered in further morphometrical studies of a bird species, especially in polluted areas.

Great-tailed Grackles (Quiscalus mexicanus) as Biomonitors of Atmospheric Heavy Metal Pollution in Urban Areas of Monterrey, Mexico

Heavy metals exposure has been linked to severe health problems. In Mexico, the Monterrey metropolitan area (MMA) is considered one of the most polluted industrial regions. Because birds have been used successfully as environmental biomonitors, the levels of lead, cadmium, and arsenic in feathers of Great-tailed grackles (Quiscalus mexicanus) from two sites within and one site outside the MMA were determined. One hundred birds were captured, samples were analyzed by atomic absorption spectrometry. Ciudad Universitaria had the highest mean values of lead and cadmium, 11.91 ppm d.w. and 1.66 ppm d.w., respectively. This was at least, 10- and 8-times higher than the two other sample sites. We believe that using Great-tailed grackles as bioindicators in conjunction with air pollutants sampling from meteorological stations in Monterrey City could help in making decisions when applying environmental remediation measures as well as in the selection of places for housing, school and work among others.

Heavy Metal Assessment in Feathers of Eurasian Magpies (Pica pica): A Possible Strategy for Monitoring Environmental Contamination?

In the present study, the Eurasian magpie (Pica pica), was evaluated as a possible bioindicator of environmental pollution by heavy metals (HMs). Levels of Ni, Pb, Cd, and Hg in feathers of 64 magpies (31 males and 33 females) were measured by ICP-MS technique. Plasmatic biomarkers of oxidative stress (OS) were also assessed. The birds were captured in the province of Parma (Italy), in different capture sites within 1 km from urban area (UZ), and farther than 5 km from urban area (RZ). Median HM levels were 0.68 mg/kg (0.18–2.27), 2.80 mg/kg (0.41–17.7), <limit of detection (LOD) mg/kg (<LOD–0.25), 3.90 mg/kg (1.35–85.9) for Ni, Pb, Cd and Hg, respectively. No significant differences in HM levels were found according to sex, while Ni and Pb were significantly higher in adult compared to young birds (p = 0.047, p = 0.004). Conversely, Cd and Hg levels in young magpies resulted higher than those of adults (p = 0.001 and p = 0.004). No correlation was found between OS biomarkers and HM levels. No differences were found in HM levels according to capture area, except for Hg level, which resulted higher in magpies of RZ (4.05 mg/kg (1.35–12.7)) compared to UZ (2.99 mg/kg (1.54–85.9)). Further experiments are needed to establish whether magpie feathers could represent a suitable non-invasive tool for biomonitoring HMs in the environment.

The urban lead (Pb) burden in humans, animals and the natural environment

Centuries of human activities, particularly housing and transportation practices from the late 19th century through the 1980's, dispersed hundreds of millions of tons of lead into our urban areas. The urban lead burden is evident among humans, wild and domesticated animals, and plants. Animal lead exposures closely mirror and often exceed the lead exposure patterns of their human partners. Some examples: Pigeons in New York City neighborhoods mimicked the lead exposures of neighborhood children, with more contaminated areas associated with higher exposures in both species. Also, immediately following the lead in drinking water crisis in Flint MI in 2015, blood lead levels in pet dogs in Flint were 4 times higher than in surrounding towns. And combining lead's neurotoxicity with urban stress results in well-characterized aggressive behaviors across multiple species. Lead pollution is not distributed evenly across urban areas. Although average US pediatric lead exposures have declined by 90% since the 1970s, there remain well defined neighborhoods where children continue to have toxic lead exposures; animals are poisoned there, too. Those neighborhoods tend to have disproportionate commercial and industrial lead activity; a history of dense traffic; older and deteriorating housing; past and operating landfills, dumps and hazardous waste sites; and often lead contaminated drinking water. The population there tends to be low income and minority. Urban wild and domesticated animals bear that same lead burden. Soil, buildings, dust and even trees constitute huge lead repositories throughout urban areas. Until and unless we begin to address the lead repositories in our cities, the urban lead burden will continue to impose enormous costs distributed disproportionately across the domains of the natural environment. Evidence-based research has shown the efficacy and cost-effectiveness of some US public policies to prevent or reduce these exposures. We end with a series of recommendations to manage lead-safe urban environments.

The effect of air pollution on immunological, antioxidative and hematological parameters, and body condition of Eurasian tree sparrows

Air pollution constitutes potential threats to wildlife and human health; therefore, it must be monitored accurately. However, little attention has been given to understanding the toxicological effects induced by air pollution and the suitability of bird species as bioindicators. The Eurasian tree sparrow (Passer montanus), a human commensal species, was used as a study model to examine toxic metal accumulation, retention of particulate matter (PM), immunological and antioxidant capacities, and hematological parameters in birds inhabiting those areas with relatively higher (Shijiazhuang city) or lower (Chengde city) levels of PM_2.5 and PM₁₀ in China. Our results showed that Shijiazhuang birds had significantly more particle retention in the lungs and toxic metal (including aluminum, arsenic, cadmium, iron, manganese, and lead) accumulation in the feathers relative to Chengde birds. They also had lower superoxide dismutase, albumin, immunoglobulin M concentrations in the lung lavage fluid, and total antioxidant capacity (T-AOC) in the lungs and hearts. Furthermore, although they had higher proportions of microcytes, hypochromia, and polychromatic erythrocytes in the peripheral blood (a symptom of anemia), both populations exhibited comparable body conditions, white cell counts, heterophil and lymphocyte ratios, and plasma T-AOC and corticosterone levels. Therefore, our results not only confirmed that Shijiazhuang birds experienced a greater burden from environmental PM and toxic metals but also identified a suite of adverse effects of environmental pollution on immunological, antioxidative, and hematological parameters in multiple tissues. These findings contribute to our understanding of the physiological health consequences induced by PM exposure in wild animals. They suggest that free-living birds inhabiting urban areas could be used as bioindicators for evaluating the adverse effects induced by environmental pollution.

Assessment of heavy metals in faecal pellets of blue rock pigeon from rural and industrial environment in India

The study was conducted to monitor concentration of six toxic metals in faecal pellets of blue rock pigeon from six industrial areas of Jaipur, i.e. Jhotwara, Malviya, Mansarover, Sitapura, Vishwakarma industrial areas and Sanganer industries, by using atomic absorption spectrophotometer. At the same time, trace metals were also analysed for a reference area so that a comparative impact of the metal pollution from the industries could be figured out. From the data obtained, the highest Cd, Cu, Ni, Pb and Zn concentrations were found in the faecal pellets from Sitapura industrial area (1.12 ± 0.60 μg/g; 128.9 ± 11.10 μg/g; 17 ± 2.87 μg/g; 79.6 ± 42.69 μg/g; 2250 ± 1390.16 μg/g) and the highest Cr (18.6 ± 3.65 μg/g) from Jhotwara industrial area. However, industrial environment has high deposition of studied trace metals (except Ni for Sanganer industries) as compared with reference area. The concentration of Cd was below the detectable level in faecal pellets from reference area. The trend of trace metals from Malviya, Sitapura, Jhotwara and reference areas was noticed as Zn > Cu > Pb > Cr > Ni > Cd and almost same for Sanganer industries and Mansarover industrial area as Zn > Cu > Cr > Pb > Ni > Cd. The excretion of heavy metals in fa1ecal pellets from Vishwakarma industrial area was noticed as Zn > Cr > Cu > Pb > Ni > Cd. Further levels of metals were varied significantly among different industrial areas, P ≤ 0.05, as well as between industrial areas and reference area. The observed high concentration of different heavy metals in faecal pellets of bird species shows their exposure to metal contamination which is warning to spiked environmental pollution.

Bioaccumulation of heavy metals in eggshell and egg content of seabirds: Lesser (Thalasseus bengalensis) and Greater Crested Tern (Thalasseus bergii)

The Persian Gulf, the most important marine ecosystem, and its islands are negatively impacted by development and pollution. Different types of pollution, especially heavy metals in these habitats, may create risks to birds, influencing reproductive performance, survival, and behaviors. Heavy metals (Cd, Pb, Cr) were analyzed in two long-lived and top food web-level sea birds, Lesser (Thalasseus bengalensis) and Greater Crested Tern (Thalasseus bergii). The research was carried out during 2018 on Nakhiloo Island, located in Dayyer-Nakhiloo Marine National Park, northeastern Persian Gulf, Iran. The nests were selected randomly, and 40 eggs of colonially-nesting terns (20 eggs T. bengalensis and 20 eggs T. bergii; a single egg per nest) were collected. The concentration of heavy metals in eggshells and egg contents was studied to investigate whether bioaccumulation varies between the eggshells and egg contents and also varies in both species. There were significant differences in the amounts of Cd between eggshell and egg content in the Greater and Lesser Crested Tern. This difference was not significant in the concentrations of Pb between the eggshell and egg content in the Tern species. Concentration of Cr did not appear to accumulate in the egg content and was below detection limit. There were significant differences in the concentrations of Cd in the eggshells and egg content between the Greater and Lesser Crested Tern. The results serve to improve understanding and to evaluate the dynamics of heavy metals in eggshells and egg content in various avian species.

Effects of experimental lead exposure on physiological indices of nestling great tits Parus major: haematocrit and heterophile-to-lymphocyte ratio

Lead (Pb) is recognized as one of the most toxic trace elements that can induce a wide range of negative health effects in wildlife. Because the investigation of basic environment-sensitive physiological indicators is easy to perform in wild birds, they have been considered as valuable bioindicators of lead contamination. The harmfulness of lead poisoning can depend on the type of exposure, and in most studies of birds, an effect of chronic lead exposition has been considered. In this study, we investigated whether a single exposure to specific doses of lead affected such physiological indices as haematocrit and the heterophil-to-lymphocyte ratio (H/L ratio). For this purpose, we conducted an experiment based on intentional lead supplementation, with the use of two different doses, applied to randomly chosen great tit (Parus major) nestlings from randomly selected broods. A few days after the exposure (when the nestlings were 15 days old), we determined haematocrit and the H/L ratio as potentially sensitive physiological indicators of lead intoxication. We found that the treatment with lead resulted in a significant decline in haematocrit level. In addition, we found that the age when lead exposure occurred can be considered as an important factor influencing haematocrit variation. A decrease in haematocrit was observed on consecutive days of nestling life. In contrast, the H/L ratio did not show any significant response to lead exposure. These results clearly show that the assessment of haematocrit level for nestling great tits can provide a simple and rapid method of indirect evaluation of physiological effects of lead intoxication caused by a single exposure.

Variations in tree sparrow (Passer montanus) egg characteristics under environmental metal pollution

Environmental metal pollution is known to adversely affect bird reproduction, for which the variations of egg characteristics are considered very important. Our study explored whether variations in egg characteristics, such as egg volume, eggshell spotting pattern, eggshell coloration, and eggshell thickness, were correlated with heavy metal levels (Cu, Zn, Pb, and Cd) and Ca levels in the eggshells of tree sparrows (Passer montanus), a widespread passerine species. Eggs were collected from a long-term heavy metal polluted area (Baiyin, BY, northwest China) and a relatively unpolluted area (Liujiaxia, LJX, northwest China). Our results showed that the embryonated (eggshell: Cu: p = 0.003, Pb: p = 0.002) and non-embryonated (egg contents: Pb: p = 0.044, Ca: p = 0.045) eggs collected from BY contained relatively higher metal concentrations than those from LJX. Eggs from BY were smaller in volume (p < 0.01) and thinner in eggshell thickness (p < 0.01) than those from LJX. Mean egg volume increased with clutch size in BY (p = 0.017), which was also accompanied by an increase in the within-clutch coefficient of variation (CV) for egg volume (p = 0.045). Clutches with a higher CV for egg volume tended to contain higher concentrations of Zn and Pb (Zn: p = 0.084; Pb: p = 0.081) in the eggshells from BY. No differences were found in the eggshell spotting coverage ratio of eggs; however, eggshells were much darker in BY than in LJX. A more aggregated eggshell spotting distribution indicated higher eggshell Zn and Pb levels (BY: Zn: p = 0.040, Pb: p = 0.076; LJX: Pb: p = 0.066). The results demonstrate that the egg characteristics of tree sparrows can be used as indicators of metal pollution, especially for the within-clutch CV for egg volume, eggshell spotting pattern and eggshell coloration.

Tools for non-invasive sampling of metal accumulation and its effects in Mediterranean pond turtle populations inhabiting mining areas

Among reptiles, freshwater turtle species have high potential for metal accumulation because of their long lifespan or their aquatic and terrestrial habits. In order to monitor metal bioaccumulation, determine potential toxic effects, and investigate tools for non-invasive metal sampling in reptiles, we studied lead (Pb) and mercury (Hg) accumulation in Mediterranean pond turtles (Mauremys leprosa) inhabiting two former mining areas, one of them with high environmental concentrations of Pb (Sierra Madrona-Alcudia Valley district) and the other one with high environmental concentrations of Hg (Almadén district). Individuals from the Pb mining area showed mean blood concentrations (i.e. 5.59 μg Pb/g dry weight, d.w.) that were higher than those measured in other populations. Blood Hg concentrations were highest (8.83 μg Hg/g d.w.) in the site close to the former Hg mines, whereas blood Hg concentrations in terrapins from another site of Almadén district, located ∼28 km downstream, were not different from locations at the non-mining area. Animals from the Pb-contaminated site showed evidence of oxidative stress, whereas those from the Hg-contaminated site showed increased activity of the antioxidant enzyme glutathione peroxidase, as well as reduced circulating levels of the main endogenous antioxidant peptide, glutathione. Concentrations measured in feces and carapace scutes were useful indicators to monitor blood concentrations of Pb, but not of Hg. Our results provide evidence of the usefulness of freshwater turtles as sentinels of chronic metal pollution, and validate non-invasive tools to advance Pb monitoring in reptiles.

Assessment of heavy metals in different organs of cattle egrets (Bubulcus ibis) from a rural and urban environment in Pakistan

The study was conducted to evaluate the concentration of essential elements (Cu, Fe, Mn, Ni, Se, Zn, and B) and non-essential elements (Cd, Pb, Hg, Cr, As, and Ni) in muscle, liver, bone, and intestine of matured cattle egret (Bubulcus ibis). Sampling was carried out at two sites of Lahore, Pakistan-Havalian Karbath (site I) and Mehmood Booti (site II)-over a period of 1 month in the winter season. Metal analyses of samples were carried out using inductively coupled plasma mass spectroscopy (ICPMS). The trend of essential elements in liver and intestine of site I was noticed as Fe > Zn > Cu > B > Mn > Se > Ni and almost same for bone and muscle as Fe > Zn > B > Mn > Cu > Se > Ni. It was noticed that Cu was less deposited in bone and muscle tissues compared to liver and intestine from site I. The deposition of essential elements in liver and intestine from site II was noticed as Fe > Zn > Cu > Mn > B > Se > Ni. Similar trend was found for bone and muscle: Fe > Zn > B > Mn > Cu > Se > Ni with great deposition of B than Cu compared to liver and intestine. The findings of the present study revealed almost similar trend for essential elements deposition at both sites. However, a random trend was observed for deposition of non-essential elements (Ag, As, Ba, Cd, Cr, Hg, Pb) in organs from both sites. Moreover, data showed higher levels of non-essential elements accumulation (particularly As, Ba, and Pb) in the body tissues/organs of cattle egret in an urban area (site II) as compared to rural area (site I) of Lahore. Furthermore, non-essential elements were more in intestine, bone, and muscles from site II showing more exposure to some non-essential elements at urban site due to human and natural activities. However, higher concentration of non-essential elements in liver from site I as compared to other organs not only reflect the land exposure to plant growth promoting fertilizers and sewage water for irrigation purpose but also better detoxification abilities of the rural birds. The study gave a new insight to inform contamination levels in the rural and urban sites. Future implications of this study need remediation strategies to clean environment requisite for avian species.

Analysis of 11 trace elements in flight feathers of Italian Sparrows in southern Italy: A study of bioaccumulation through age classes, variability in three years of sampling, and relations with body condition

Trace elements have been acknowledged as one of the subtlest environmental hazards in all compartments of the total environment. Enhanced by activities in the anthroposphere, they accumulate in the atmosphere, lithosphere, and hydrosphere. Eventually, trace elements can bioaccumulate or biomagnifiy in the biosphere, with harmful effects on animals occupying higher trophic levels, including humans. Accordingly, there is great interest in assessing and monitoring trace element concentrations in the biosphere, and birds, especially passerines, have been commonly chosen as biomonitors. In this study, the concentration of 11 trace elements was measured (i.e. aluminum, chromium, manganese, iron, nickel, copper, zinc, arsenic, cadmium, barium, and lead) in flight feathers of Italian Sparrows, a common bird species hitherto not analysed in this respect. Samples were collected in an agricultural area in southern Italy, where a mosaic of natural environments, urbanized areas and industrial facilities can be found. Linear mixed modelling was applied to the analysis of flight feathers in juveniles, juvenile birds moulting to adulthood, and adults in three sampling years on 184 birds. Results are timely as they add new data to the scarce available information on Ba and As in bird feathers and showed clear bioaccumulation patterns from juveniles to adults for As, Cr, and Cd. Moreover, the modelling approach showed that the concentration of elements such as As, Cd and Cr can be variable across the years and that some elements, notably Cd and Ba, were inversely correlated with body mass and wing length, respectively, suggesting potential negative effects on bird health. Finally, when modelling bird body condition and trace elements, results showed that Cd and Ba negatively affect birds regardless of age or sampling year. Thus, the Italian Sparrow could be considered as a valuable biomonitor for trace elements in the total environment, especially for Cd and Ba.

Interspecific variation in the spatially-explicit risks of trace metals to songbirds

Many wild animals can be adversely affected by trace metals around point sources but little is known about the risks to birds across their ranges. Trace metals in the soil are ubiquitously, if heterogeneously distributed, across the world due to natural and anthropogenic sources. Here, we built, parameterized and applied a spatially explicit modelling framework to determine the risks of soil-associated metals to 30 invertebrate-consuming passerine species across their spatial distribution in England and Wales. The model uses a risk characterization approach to assess the risks of soil-associated metals. Various monitoring datasets were used as input parameters: soil metal concentrations in England and Wales, bird spatial distribution; bird diet, bioaccumulation and toxicity data were extracted from the literature. Our model highlights significant differences in toxicity risks from Cd, Cu, Pb and Zn across the UK distributions of different species; Pb and Zn posed risks to all species across most of species' distributions, with more localised risks to some species of conservation concern from Cd and Cu. No single taxa of invertebrate prey drove avian exposure to metal toxicity. Adults were found to be at higher risk from Pb and Zn toxicity across their distributions than nestlings. This risk was partially driven by diet, with age differences in diets identified. Our spatially explicit model allowed us to identify areas of each species' national distribution in which the population was at risk. Overall, we determined that for all species studied an average of 32.7 ± 0.2%, 8.0 ± 0.1%, 86.1 ± 0.1% and 93.2 ± 0.1% of the songbird spatial distributions in the UK were characterized at risk of Cd, Cu, Pb and Zn, respectively. Despite some limitations, our spatially explicit model helps in understanding the risks of metals to wildlife and provides an efficient method of prioritising areas, contaminants and species for environmental risk assessments. The model could be further evaluated using a targeted monitoring dataset of metal concentration in bird tissues. Our model can assess and communicate to stakeholders the potential risks of environmental contaminants to wildlife species at a national and potentially international scale.

Lead exposure in an urban, free-ranging parrot: Investigating prevalence, effect and source attribution using stable isotope analysis

Anthropogenic lead use has resulted in widespread environmental lead contamination known to affect wildlife populations worldwide. Ecotoxicological investigations in wild birds have thus far prioritised waterfowl and raptor species and primarily addressed contamination in natural ecosystems. Urban areas are increasingly associated with high levels of heavy metal contamination, however the risk of lead exposure in urban wildlife is less well known. This study investigates lead exposure in an urban population of North Island Kaka (Nestor meridionalis septentrionalis), an endemic New Zealand parrot. The inquisitive nature of these birds, an expanding urban population and increased availability of food in the urban environment are the primary factors implicated in their dispersal into urban areas where there is increased exposure to anthropogenic sources of lead. Blood lead concentrations were assessed in free-ranging birds to quantify the prevalence and magnitude of lead exposure. The impact of lead on physiological and neurological function was assessed using behavioural and clinical examinations. Finally, lead stable isotope analysis was employed to investigate lead in roofing material as a potential source of exposure in the urban environment. Results indicate a significant prevalence of lead exposure in this population (43.2%) with a maximum recorded plasma concentration of 50.7μg/dL. Although no mortality was observed during this study, lead exposure was associated with reduced body condition in kaka. Behavioural changes were present in one individual with the highest recorded blood lead concentration. Lead isotope values of roof-collected rainwater overlapped with kaka blood lead isotope values, suggesting this to be an important source of exposure in this population. The prevalence of lead exposure observed in this study suggests that lead is a toxin of importance to kaka in this urban area. Wildlife intoxications largely result from anthropogenic lead sources and this study identifies a previously undescribed urban source of lead for wildlife.

Signatures of human-commensalism in the house sparrow genome

House sparrows (Passer domesticus) are a hugely successful anthrodependent species; occurring on nearly every continent. Yet, despite their ubiquity and familiarity to humans, surprisingly little is known about their origins. We sought to investigate the evolutionary history of the house sparrow and identify the processes involved in its transition to a human-commensal niche. We used a whole genome resequencing dataset of 120 individuals from three Eurasian species, including three populations of Bactrianus sparrows, a non-commensal, divergent house sparrow lineage occurring in the Near East. Coalescent modelling supports a split between house and Bactrianus sparrow 11 Kya and an expansion in the house sparrow at 6 Kya, consistent with the spread of agriculture following the Neolithic revolution. Commensal house sparrows therefore likely moved into Europe with the spread of agriculture following this period. Using the Bactrianus sparrow as a proxy for a pre-commensal, ancestral house population, we performed a comparative genome scan to identify genes potentially involved with adaptation to an anthropogenic niche. We identified potential signatures of recent, positive selection in the genome of the commensal house sparrow that are absent in Bactrianus populations. The strongest selected region encompasses two major candidate genes; COL11A-which regulates craniofacial and skull development and AMY2A, part of the amylase gene family which has previously been linked to adaptation to high-starch diets in humans and dogs. Our work examines human-commensalism in an evolutionary framework, identifies genomic regions likely involved in rapid adaptation to this new niche and ties the evolution of this species to the development of modern human civilization.

House sparrow biomarkers as lead pollution bioindicators. Evaluation of dose and exposition length on hematological and oxidative stress parameters

House sparrows (Passer domesticus) have been proposed as a key ecological indicator of urban pollution. Remarkably, we lack knowledge about the physiological effects of lead on this bird species. Therefore, this study was aimed to evaluate the effect of Pb on several physiological parameters in house sparrows exposed to environmental Pb concentrations. In a first experiment, birds were exposed to Pb sub-lethal doses (from 1.3 to 14.0 µg of Pb/g animal/day) during 5 days, which resulted in a dose response increase of blood Pb levels and decrease of blood ALAD activity. However, at the higher doses tested (> 7 μg of Pb/g animal/day) the blood ALAD activity inhibition (~82%) remained constant. Hematocrit and hemoglobin were significantly reduced only at the highest-doses, and the stress indicator, heterophils to lymphocyte (H/L) ratio, did not show apparent changes. In a second experiment, house sparrows were exposed to Pb in drinking water (12.3 ppm) during either 15 or 30 days. Pb concentration used in this study was enough to produce blood lead levels equivalents to those found recently in house sparrows inhabiting urban areas, reduced blood ALAD activity and inversion of the H/L ratio. Decreasing blood ALAD activities were correlated with increasing blood Pb levels. In addition, Pb exposure produced modification in the levels of hepatic antioxidant enzymes, increased GST activity and decreased CAT activity, without lipid peroxidation. In conclusion, our results suggest that blood ALAD activity is a reliable and sensitive biomarker for environmental Pb exposure in house sparrows, additionally chronic exposure produce physiological stress (H/L inversion) and small changes in antioxidant enzyme activity. Finally, this specie could be considered a bioindicator for monitoring the urban Pb contamination.

Nephrotoxicity in Hybrid sparrow (Passer domesticus × Passer hispaniolensis) living near a phosphate treatment factory complex in southern Tunisia: a biochemical and histological study

Our study was designed to evaluate impacts of exposure to pollutants, released by the Gabès-Ghannouche factory complex of phosphate treatment, on biochemical biomarkers and histopathological indices in kidney tissues of Hybrid sparrow (Passer domesticus × Passer hispaniolensis) in Gabès city. Our results show evidence of a pronounced impairment in kidney function which is confirmed by remarkable blood chemical alterations in sparrows living in Ghannouche, the most polluted site. Moreover, superoxide dismutase and catalase activities were found to be decreased in birds sampled from the contaminated site when compared to less polluted areas. The population of sparrows feeding in Ghannouche had enhanced renal thiobarbituric acid reactive substance levels, indicating oxidative damage to membrane lipids. Some histopathological alterations were also observed including kidney interstitial dilatations. Overall, our findings demonstrated that the exposure to pollutants released by the factory complex possessed nephrotoxic by depleting renal antioxidant defense system and promoting kidney morphometric damage in sparrows. These results constitute an early warning of an ecological change in relation to human health.

Metal concentrations in homing pigeon lung tissue as a biomonitor of atmospheric pollution

Atmospheric pollution in urban areas is a major worldwide concern with potential adverse impacts on wildlife and humans. Biomonitoring can provide direct evidence of the bioavailability and bioaccumulation of toxic metals in the environment that is not available with mechanical air monitoring. The current study continues our evaluation of the usefulness of homing pigeon lung tissue as a biomonitor of atmospheric pollution. Homing pigeons (1-2, 5-6, and 9-10+ year old (yo)) collected from Guangzhou during 2015 were necropsied and concentrations of cadmium (Cd), lead (Pb), and mercury (Hg) were measured in lung tissue. Lung Cd and Pb concentrations were significantly greater in 9-10+-year-old pigeons compared with those in other age groups, indicating their bioavailability and bioaccumulation. Lung Pb and Cd concentrations measured in 5-yo pigeons collected from Guangzhou during 2015 were significantly lower than concentrations reported in 5-yo homing pigeons collected from Guangzhou during 2011 and correlated with concentrations measured using mechanical air monitoring. In addition to temporal differences, spatial differences in concentrations of Cd, Pb, and Hg reported in ambient air samples and in pigeon lung tissues collected from Beijing and Guangzhou are discussed.

Relationship between Pb and Cd accumulations in house crow, their habitat, and food content from Klang area, Peninsular Malaysia

Heavy metal pollution has become a global concern due to accumulation in tissue and transferable effects to humans via the food chain. This study focused on monitoring the accumulation of cadmium (Cd) and lead (Pb) in surface soil and body content: bone, heart, brain, liver, lung, muscle, kidney, feathers, feces, and gizzard contents of house crow Corvus splendens in the Klang region, Malaysia. The results revealed the occurrence of Pb and Cd in all biological samples from house crows, food contents, and surface soil samples. Heart and kidney accrued high amounts of Cd, while high amounts of Pb were found to accumulate in bones and feathers. Major discrepancies were also discovered in the concentrations of metals between juvenile and adults, as well as female and male bird samples. Concentrations of Pb and Cd in house crow internal tissues correlated significantly with that of bird feathers, but none could be established with that of surface soil. In addition, a significant correlation was observed between Pb concentration in the internal tissues to that of the feces, but the same was not the case when compared with the surface soil concentration. Metal accrual in the house crows feathers and feces may be through a long-term transmission via the food chain, which are eliminated from feathers via molting. This may suggest the utility of molted breast feathers of house crow in the bio-monitoring of Cd and Pb contamination, whereas feces of house crow appear only to be suitable for the bio-monitoring of Pb contamination.

Stress induced by heavy metals on breeding of magpie (Pica pica) from central Iran

The aim of this study was to address the impacts of some heavy metals (Cd, Pb, Zn, Ni and Cu) contamination on laying behavior, egg quality and breeding performance of Pica pica in north of Isfahan Province, Iran. During the breeding season of 2013, magpie's egg content and eggshell as well as nestling excrements and feathers were collected and total concentrations of heavy metals were measured by ICP-OES. Except for Zn in nestling feathers, the significantly higher concentrations of heavy metals were observed in nestling excrements than other samples. Also, comparison of heavy metals concentrations in egg content and eggshell showed that egg content had significantly higher concentrations of Zn and Pb, instead eggshell had significantly higher amount of Cu and Cd. Except for Cu, all heavy metals concentrations in eggshell had a negative relationship with morphological characters; and also concentration of Cu in egg content showed a significantly negative correlation with egg weight and volume. The most of heavy metals in nestling feathers and excrements had strongly positive correlations with each other. Also all heavy metals levels in eggshell and egg content had significantly positive correlations (except for Cu). Unhatched eggs had significantly lower weight but also greater levels of Zn, Cd, and Pb, than randomly collected eggs. No significant differences were observed for morphometric measurements of eggs between different sites, however, a decreased gradient was observed in egg volume toward the brick kiln site. Samples collected in brick kiln site accumulated higher concentrations of heavy metals than other sites. Although numbers of clutch size in brick kiln site were significantly higher than other sites, however, other breeding variable were lower than other sites. It can be suggested that ecosystem contamination may be caused to decrease the reproduction rate of Pica pica in brick kiln, probably by laying more poor quality eggs per clutch and nestling mortality.