Lead isotope ratio measurements as indicators for the source of lead poisoning in Mute swans (Cygnus olor) wintering in Puck Bay (northern Poland)

Identifying the origin of lead poisoning in white-backed vulture (Gyps africanus) chicks at an important South African breeding colony: a stable lead isotope approach

Elevated lead levels in scavenging raptors can originate from a variety of environmental and anthropogenic sources, including soil, water, mining activities and legacy lead from leaded fuel, but has mostly been attributed to fragments of lead-based ammunition embedded in the tissues of carcasses. To identify the origins of lead in the tissues of white-backed vulture (Gyps africanus) chicks at Dronfield Nature Reserve, South Africa, we used MC-ICP-MS to compare the isotopic composition of lead in blood samples to those of soil in the chicks' immediate environment, different mining activities in South Africa and lead ammunition commonly used in hunting and game management practices. The isotopic ratios in vulture blood samples ranged widely (207Pb/206Pb: 0.827-0.911), but fell within those measured for ammunition (0.761-0.938). Dronfield water can be excluded as a significant source, as the lead concentration for water was below detection limits. Uranium, coal, atmospheric Pb, legacy Pb from fuel and Pb mining can also be excluded as significant sources, based on the limited overlap with Pb isotopic ratios measured in vulture blood. Whereas 55% of chicks we sampled displayed isotopic ratios consistent with Dronfield soil, the low local Pb concentration and the low extractable Pb levels in South African soil in general, imply that soil Pb is unlikely the major source of Pb in WBV chicks, especially in birds with elevated blood Pb levels, i.e. > 20 µg/dL. Our results, when considered in the context of vulture feeding ecology and low Pb levels in non-scavenging birds in South Africa, imply the major source of elevated Pb levels in WBV chicks to be fragments of lead-based ammunition embedded in the carrion fed to them by their parents.

Mercury in the Polish part of the Baltic Sea: A response to decreased atmospheric deposition and changing environment

Our review of the literature showed that since the beginning of the socio-economic transformation in Poland in the 1990s, the downward trend in Hg emissions and its deposition in the southern Baltic Sea was followed by a simultaneous decrease in Hg levels in water and marine plants and animals. Hg concentrations in the biota lowered to values that pose no or low risk to wildlife and seafood consumers. However, in the first decade of the current century, a divergence between these two trends became apparent and Hg concentrations in fish, herring and cod, began to rise. Therefore, increasing emission-independent anthropogenic pressures, which affect Hg uptake and trophodynamics, remobilization of land-based and marine legacy Hg deposits, as well as the structure of the food web, can undermine the chances of reducing both the Hg pool in the marine environment and human Hg exposure from fish.

Do the diverse environments of Baltic coastal zone affect hematological and biochemical alterations in the blood of mute swans (Cygnus olor)?

Based on studies of the wintering population of mute swans in large urban agglomerations, it is possible to identify and infer the impact of environmental pollution in coastal regions near Baltic Sea on the physiological and biochemical changes in the blood of waterfowls. Hematological and biochemical changes in the blood in relation to chemical elements in their feathers are a useful tool for general ecophysiological conclusions. Hematological changes and blood chemistry in Mute Swan Cygnus olor is particularly environmentally dependent, therefore we examined hematological picture (red blood cells RBC, white blood cells WBC, heterophiles, eosinophils, basophils, monocytes, lymphocytes, hemoglobin, heterophile to lymphocyte ratio H/L, biochemical indicators (glucose, uric acid, total cholesterol, triglycerides, calcium, inorganic phosphorus, magnesium, total protein), stability of erythrocyte membranes, concentration of Ca, P, Mg in the blood, concentration of Al, Zn, Rh, Cu, Ru, Fe, Pb in feathers, in wintering population of 172 mute swans of different age (juvenile, adult) and gender, in three coastal types of areas of Southern Polish zone of Baltic Sea (Słupsk, Gdynia, Sopot). Percentage of changes in the morphological indices in the blood of mute swans with three independent characteristics (environment, sex, age) revealed that hemoglobin content exhibited the highest value (R² = 53.8%) in the analysis of morphological indices; the effect of RBC, WBC, and basophils was much lower (WBC > RBC > basophils). Male and female erythrocytes from the coastal of Gdynia were more fragile than those of birds from coasts of Sopot and Słupsk. We found that osmotic fragility is altered in juvenile swans from Słupsk area and males from Gdynia area. The consequence was a higher level of hemolyzed erythrocytes in their blood. The effect of type of environment, age-, and sex-related impact on hematological indices and biomarkers of biochemical alterations in the blood of swans and comparison of these data with bioaccumulation of chemical elements in feathers of swans inhabiting 3 types of environment of Baltic coastal zone show significant differences in the hematological and biochemical indices. Albumins and globulins maintain the blood cations balance, however, changes in their concentrations in the blood suggest an impact on physiological mechanisms and body condition of swans.

Spatial, temporal and environmental differences in concentrations of lead in the blood of Mute swans from summer and winter sites in Poland

Lead (Pb) is a highly toxic pollutant and represents a serious threat to wildlife, affecting various systems in animal bodies. Especially prone to Pb poisoning are waterbirds, which may inadvertently ingest spent gunshot, fishing sinkers and contaminated sediments. This research thus focused on evaluating Pb concentrations in the blood of 170 Mute swans (Cygnus olor; a widespread species of waterbirds) at their summer (urban locations in Małopolskie and rural locations in Świętokrzyskie regions) and winter (the urban section of Wisła River in Krakow) sites in Poland (Europe). The study concentrated on comparing blood Pb concentrations according to sites and locations, verifying the influence of sex and age factors, examining the impact on hematocrit (Ht), glutathione (GSH) levels and body condition. Mean blood Pb concentrations (measured with ICP-OES) differed significantly between summer and winter sites (Regression by Maximum Likelihood Estimation (RML), p < 0.001) reaching higher values at winter sites. Concentrations did not differ from year to year (RML, p = 0.028). At summer sites, concentrations differed from location to location: swans from urban locations in Małopolskie had higher blood Pb concentrations (0.055 μg/g) than from rural Świętokrzyskie (0.008 μg/g; RML, p < 0.001). In summer and winter birds, neither sex nor age groups differed significantly the concentrations (RML, p > 0.231). Pb concentrations correlated weakly with Ht and GSH levels (Spearman test) and had no influence on body condition (proxied by scaled mass index; GLM, p = 0.246). We concluded that differences between summer and winter sites were dictated mainly by the type of habitat (rural vs. urban) that birds occupied in different seasons.

Children's exposure to environmental lead: A review of potential sources, blood levels, and methods used to reduce exposure

Lead has been used for thousands of years in different anthropogenic activities thanks to its unique properties that allow for many applications such as the manufacturing of drinking water pipes and its use as additives to gasoline and paint. However, knowledge of the adverse impacts of lead on human health has led to its banning from several of its applications, with the main goal of reducing environmental pollution and protecting human health. Human exposure to lead has been linked to different sources of contamination, resulting in high blood lead levels (BLLs) and adverse health implications, primarily in exposed children. Here, we present a summary of a literature review on potential lead sources affecting blood levels and on the different approaches used to reduce human exposure. The findings show a combination of different research approaches, which include the use of inspectors to identify problematic areas in homes, collection and analysis of environmental samples, different lead detection methods (e.g. smart phone applications to identify the presence of lead and mass spectrometry techniques). Although not always the most effective way to predict BLLs in children, linear and non-linear regression models have been used to link BLLs and environmental lead. However, multiple regressions and complex modelling systems would be ideal, especially when seeking results in support of decision-making processes. Overall, lead remains a pollutant of concern and many children are still exposed to it through environmental and drinking water sources. To reduce exposure to lead through source apportionment methods, recent technological advances using high-precision lead stable isotope ratios measured on multi-collector induced coupled plasma mass spectrometry (MC-ICP-MS) instruments have created a new direction for identifying and then eliminating prevalent lead sources associated with high BLLs.

Gastrointestinal and respiratory exposure of water birds to endocrine disrupting phenolic compounds

Aquatic birds found at the top of the trophic chain are exposed to xenobiotics present both in food and inhaled air. The aim of this study was to indicate and assess the routes and levels of exposure of aquatic birds to bisphenol A (BPA), 4-tert-octylphenol (4-t-OP) and 4-nonylphenol (4-NP). The birds constituting the study material (Clangula hyemalis, Alca torda, Mergus merganser) originated from by-catches (winter 2014-2016) in the Southern Baltic. The studies show that the exposure of birds to phenol derivatives is determined by the specifics of a compound, the habitat area, trophic level and food consumed. BPA was characterized by the highest intestinal concentrations in all birds (6.6-1176.2 ng^.g^-1 dw). Higher concentrations of 4-t-OP were determined in the lungs of birds from the eastern part of the Southern Baltic (9.1-135.7 ng^.g^-1 dw) and in the intestines of birds from the western part (<0.5-191.4 ng^.g^-1 dw). In the case of 4-NP, higher concentrations were found in the intestines of carnivorous species (64.9-524.5 ng^.g^-1 dw), and the lungs of benthos-eating species (39.4-399.7 ng^.g^-1 dw). The intestines that were most burdened with 4-NP were those of birds from the highest trophic level. Correlations between the concentrations of phenol derivatives in the blood and the intestines and lungs indicated that birds are exposed to the penetration of phenol derivatives through the digestive and respiratory tracts. BPA and 4-NP were characterized by the highest concentrations in the intestines and lungs, whereas 4-t-OP in blood (3.2-39.2 ng^.cm^-3), which may indicate the largest endocrine potential of this compound in birds. Significant differences in phenol derivatives concentrations in the intestines and lungs of birds from the western and eastern part of the Southern Baltic, shows that these tissues can be useful for assessing the contamination of the environment with EDCs.

Application of Stable Isotopic Ratio Analysis to Identify the Cause of Acute Versus Chronic Lead Poisoning of a Tundra Swan (Cygnus columbianus): A Case Study

We utilized lead (Pb) stable isotopes to identify the source of acute Pb poisoning in a Tundra Swan (Cygnus columbianus) and evaluated overall Pb exposure. Upon necropsy, we obtained samples of blood, liver, kidney, heart, thigh, breast, femur, and metallic objects (i.e., fishing sinker, spring and swivels) from the gizzard for Pb isotopic analysis. Pb isotope ratios of blood and soft tissues were essentially identical to the Pb ratios of the sinker, the likely source of acute poisoning. The spring and swivels had lower Pb content and ratios distinct from tissue, suggesting no significant contribution to poisoning. Femur Pb isotopic composition was the most distinct biological sample and indicative of a combination of sources. These results demonstrate isotopic analysis as a viable method for determining the source of acute Pb poisoning, and that Pb isotope ratios in bone most likely record a lifetime-averaged metric of Pb exposure.

Dust and bullets: Stable isotopes and GPS tracking disentangle lead sources for a large avian scavenger

Lead intoxication is an important threat to human health and a large number of wildlife species. Animals are exposed to several sources of lead highlighting hunting ammunition and lead that is bioavailable in topsoil. Disentangling the role of each in lead exposure is an important conservation issue, particularly for species potentially affected by lead poisoning, such as vultures. The identification of lead sources in vultures and other species has been classically addressed by means of stable-isotope comparisons, but the extremely varied isotope signatures found in ammunition hinders this identification when it overlaps with topsoil signatures. In addition, assumptions related to the exposure of individual vultures to lead sources have been made without knowledge of the actual feeding grounds exploited by the birds. Here, we combine lead concentration analysis in blood, novel stable isotope approaches to assign the origin of the lead and GPS tracking data to investigate the main foraging grounds of two Iberian griffon vulture populations (N = 58) whose foraging ranges differ in terms of topsoil lead concentration and intensity of big game hunting activity. We found that the lead signature in vultures was closer to topsoil than to ammunition, but this similarity decreased significantly in the area with higher big game hunting activity. In addition, attending to the individual home ranges of the tracked birds, models accounting for the intensity of hunting activity better explained the higher blood lead concentration in vultures than topsoil exposure. In spite of that, our finding also show that lead exposure from topsoil is more important than previously thought.

Lead isotopic signatures in blood from incubating common eiders (Somateria mollissima) in the central Baltic Sea

The Christiansø colony of common eiders (Somateria mollissima) in the central Baltic Sea were exposed to high levels of Pb during the 2018 breeding season that were not present in 2017. Due to these high Pb blood levels, the present study investigated possible Pb sources and Pb dynamics within this vulnerable colony. We analyzed body mass and lead isotopic ratios (Pb-IRs) in blood taken from the same incubating eiders at the early (day 4) and late (day 24) stages of incubation during the 2018 breeding season (n = 23). Pb-IRs 208/207, 208/206, 206/207, and 207/206 were analyzed using high resolution inductively coupled mass spectrometry. We found largely similar Pb-IRs from the different stages of incubation indicating a predominantly constant endogenous source of Pb exposure. We suggest the increasing Pb levels come from pre-nesting and nesting foraging and from medullary bone release. The similar Pb-IRs also indicate continued metabolization of the medullary bone to meet the nutritional and energy demands of incubation. Comparisons to Pb-IR reports from the Baltic Sea showed multiple sources of pollution distinguished by a difference between Pb-IRs in individuals with Pb blood concentrations >500 μg/kg ww and <500 μg/kg ww. The most highly contaminated individuals in the present study had Pb-IRs similar to those of Pb ammunition indicating shot pellet uptake. This study further emphasizes the need for continued biomonitoring of the Christiansø colony, including fecal sampling and environmental field sampling to identify the origin and extent of dietary Pb exposure on Christiansø. As a representative unit of the Baltic Flyway population; the Christiansø colony provides an important opportunity for continued investigation into Pb contamination, population dynamics, and declines.

Factors associated with lead (Pb) exposure on dogs around a Pb mining area, Kabwe, Zambia

Lead (Pb)-poisoning is a serious public health concern and dogs have been useful as a sentinel-animal for Pb exposure of humans. In the present study, the blood Pb concentrations (BLC), isotope ratios (208 Pb/206 Pb and 207 Pb/206 Pb), and biochemistry of 120 domestically owned dogs living around a Pb mining area, in Kabwe, Zambia were analyzed to determine factors associated with Pb exposure. The overall mean value of Pb in dog blood in the present study was 271.6 μg/L. The BLC in the dogs from sites near the mine were significantly higher than those in the dogs from a site 4 km from the mine (352.9 ± 205.1 μg/L versus 28.0 ± 13.9 μg/L). BLC significantly decreased with both increasing age of the dogs and distance from the mine. The Pb isotope ratios in the dog that resided near the mine showed values similar to those reported at the galena mine in Kabwe, which is considered to be the source of Pb exposure. In contrast to the high metal exposure that was determined in these dogs, the mean values of most analyzed parameters in the blood biochemical analysis were surprisingly within or close to the standard reference values. Moreover, none of the dogs showed overt signs of Pb-poisoning or other clinical symptoms. The results of analysis of Pb exposure of the dogs obtained in the present study, which are similar to the previously reported results in human in this location, suggest that dogs could be useful as a sentinel animal for Pb exposure of humans in Kabwe.

Relationship between blood lead levels and physiological stress in mute swans (Cygnus olor) in municipal beaches of the southern Baltic

Lead is one of the non-essential metals that can become a serious environmental threat to the human population and wildlife causing various toxic impairments and pathologies. Waterfowl are especially sensitive to lead exposure as they stay in areas with a high risk of lead pollution due to hunting and fishing pressures. This study aims to determine recent blood lead levels in 45 live mute swans in the southern Baltic, in the Gulf of Gdańsk and to test the hypothesis that birds with elevated lead levels have a higher physiological stress. Mean concentration of lead in blood was 0.239 μg/g (range 0.028-0.675 μg/g). Almost half of the individuals examined in this study had increased blood Pb levels above the threshold level (0.23 μg/g), however none of them showed behavioural signs of Pb poisoning. Although the dominant food of mute swans staying at municipal beaches is bread delivered by people, which has low lead levels, lead was found in all blood samples taken from mute swans. In the study area, another possible source of lead poisoning, other than from ammunition, is connected with various anthropogenic activities, such as municipal sewage works. Moreover, poor diet results in greater susceptibility to absorption of lead and this may have an additional influence on elevated lead levels in blood of these birds. The Pb level was increased with heterophils to lymphocytes (H/L) ratio, which is used as a measure of longer-term physiological stress. The mean lead level in blood was higher in young birds than in adults, which may be a consequence of adults forcing them to take less calorific food from water plants containing elevated levels of lead in the area studied. However, it is difficult to disentangle this from other factors that may influence sensitivity to lead poisoning.

Blood mercury levels in mute swans (Cygnus olor) are not related to sex, but are related to age, with no blood parameter implications

Concentrations of mercury (Hg) were examined in the blood of mute swans from rural breeding sites and urban wintering areas in southern parts of Poland, Europe. The birds were classified into three age groups: cygnets, juveniles and adults. To investigate the potential impact of Hg on birds, hematocrit (Ht), reduced glutathione (GSH) levels and morphometric measurements were taken. Using morphometric parameters, we stated that all mute swans sampled were in good condition. The mercury concentrations found were rather low and differed between birds from industrialized wintering areas and rural breeding areas (means 7 ng/mL and 2 ng/mL, respectively). We found no difference in Hg concentrations between the sexes, but concentrations varied significantly between age groups (cygnets 2 ng/mL, juveniles 7 ng/mL and adults 6 ng/mL). A similar trend was observed for hematocrit levels. GSH levels did not differ between any of the groups studied. We found no significant relationship between blood parameters (Ht, GSH) in relation to Hg concentrations. We conclude that the Hg concentrations in blood may be influenced by industrialization, season and age, but generally low concentration such as those found by us do not affect Ht and GSH levels.

Effects of lead from ammunition on birds and other wildlife: A review and update

Poisoning of wild birds following ingestion of lead from ammunition has long been recognised and considerable recent research has focused on terrestrial birds, including raptors and scavengers. This paper builds upon previous reviews and finds that both the number of taxa affected and geographical spread of cases has increased. Some lead may also be absorbed from embedded ammunition fragments in injured birds which risk sub-lethal and welfare effects. Some papers suggest inter-specific differences in sensitivity to lead, although it is difficult to disentangle these from other factors that influence effect severity. Sub-lethal effects have been found at lower blood lead concentrations than previously reported, suggesting that previous effect-level 'thresholds' should be abandoned or revised. Lead poisoning is estimated to kill a million wildfowl a year in Europe and cause sub-lethal poisoning in another ≥ 3 million. Modelling and correlative studies have supported the potential for population-level effects of lead poisoning in wildfowl, terrestrial birds, raptors and scavengers.

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.

Concerns about Quadrupole ICP-MS Lead Isotopic Data and Interpretations in the Environment and Health Fields

There has been a massive increase in recent years of the use of lead (Pb) isotopes in attempts to better understand sources and pathways of Pb in the environment and in man or experimental animals. Unfortunately, there have been many cases where the quality of the isotopic data, especially that obtained by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS), are questionable, resulting in questionable identification of potential sources, which, in turn, impacts study interpretation and conclusions. We present several cases where the isotopic data have compromised interpretation because of the use of only the major isotopes ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁷Pb/²⁰⁶Pb, or their graphing in other combinations. We also present some examples comparing high precision data from thermal ionization (TIMS) or multi-collector plasma mass spectrometry (MC-ICP-MS) to illustrate the deficiency in the Q-ICP-MS data. In addition, we present cases where Pb isotopic ratios measured on Q-ICP-MS are virtually impossible for terrestrial samples. We also evaluate the Pb isotopic data for rat studies, which had concluded that Pb isotopic fractionation occurs between different organs and suggest that this notion of biological fractionation of Pb as an explanation for isotopic differences is not valid. Overall, the brief review of these case studies shows that Q-ICP-MS as commonly practiced is not a suitable technique for precise and accurate Pb isotopic analysis in the environment and health fields.

The influence of environmental conditions on lead transfer from spent gunshot to sediments and water: Other routes for Pb poisoning

Lead (Pb) from spent gunshot and fishing sinkers is recognized as the main source of Pb poisoning among waterfowl. It is also suspected to directly pollute water and sediments, but no appropriate, comprehensive evaluation of this issue has so far been carried out. An experiment on Pb pellets in microcosms (n = 160) with two sediment types (mud and gravel), three water pH values (4, 7 and 9) and two wind levels (wind and windless simulation) was therefore run. Substantial differences in Pb transfer (measured with ICP-OES) between sediment types and pH levels of water were observed. Simulated wind conditions were a significant factor only for some variables and circumstances. The strongest Pb deposit to water and sediments occurred in mud microcosms with water of pH value of 4. Median pellet erosion during the experiment differed little between sediment types. The experiment revealed that Pb transfer from spent gunshot to the environment occurs only in specific environmental conditions.