Heavy metals in flamingos (Phoenicopterus ruber) from Italian wetlands: the problem of ingestion of lead shot

Legacy and emerging contaminants in flamingos' chicks' blood from the Ebro Delta Natural Park

The Ebro Delta is a wetland of international importance for waterbird conservation but severally affected by intensive agriculture, toxic waste discharges from a past chloro-alkali industry and affluence of tourism. The discharge of contaminants associated to these activities pose waterbirds breeding in the Ebro Delta at risk. The aim of this study is to evaluate the exposure of 91 emerging and legacy micropollutants in flamingo chicks (Phoenicopterus roseus), an emblematic species of the area. Fifty chicks of 45-60 days were captured, biometric parameters measured and whole blood collected. Compounds analyzed included perfluoroalkyl substances (PFASs), pharmaceuticals, organophosphate esters (OPEs), in-use pesticides, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), and polycyclic aromatic hydrocarbons (PAHs). The results indicate a multi-exposure of flamingo's chicks from a very young age. PFASs were the most ubiquitous compounds with ∑PFASs ranging from 9.34 to 576 ng/mL, being PFOA, PFOS and PFHxS detected in all samples. ∑PAHs ranged from 0.19 to 423 ng/mL, ∑PCBs from 0.5 to 15.6 ng/mL and ∑OCs from 1.35 to 37.8 ng/mL. Pharmaceuticals, OPEs and in-use pesticides were not detected. The flamingo's filtering behavior on mud and maternal ovo-transference are the more likely routes of exposure of organic micropollutants to flamingos' chicks. The reported levels of micropollutants were not associated with any alteration in the body condition of chicks. This is the first study to describe flamingos chicks' exposure to multiple contaminants, highlighting the importance of biomonitoring for wildlife conservation and biodiversity preservation.

Heavy Metals in Sediments and Greater Flamingo Tissues from a Protected Saline Wetland in Central Spain

Aquatic ecosystems often act as sinks for agricultural, industrial, and urban wastes. Among potential pollutants, heavy metals can modify major biogeochemical cycles by affecting microorganisms and other biota. This study assessed the distribution and concentration of heavy metals (Cd, Hg, Cu, Pb, and Zn) in Pétrola Lake, a heavily impacted area in central Spain where the greater flamingo Phoenicopterus roseus breeds. This study was designed to determine the concentration and identify the potential sources of heavy metals in Pétrola Lake protected area, including sediments, agricultural soils, and tissues of the greater flamingo. A six-step sequential extraction was performed to fractionate Cu, Pb, and Zn from lake sediments and agricultural soil samples to gain insight into different levels of their bioavailability. Our results showed that Pb and Cd accumulated in lake sediments and agricultural soils, respectively, most likely derived from anthropogenic sources. Multivariate analysis revealed differences between these (Pb and Cd) and the remaining studied elements (Cu, Hg, and Zn), whose concentrations were all below the pollution threshold. Lead pollution in sediments was apparently dominated by organic matter binding, with fractions up to 34.6% in lake sediments. Cadmium slightly accumulated in agricultural soils, possibly associated with the use of fertilizers, but still below the pollution thresholds. In the flamingo samples, low bioaccumulation was observed for all the studied elements. Our study suggests that human activities have an impact on heavy metal accumulation in sediments and soils, despite being below the pollution levels.

The Impact of Pb from Ammunition on the Vegetation of a Bird Shooting Range

Hunting with lead ammunition represents a source of heavy metal pollution to the environment that can be potentially high at the local scale. Intensive hunting of small game species can concentrate high levels of ammunition discharging in small areas. This type of hunting is a relevant economic resource for private landowners in some regions of Spain, and current legislation allows the use of lead ammunition in these scenarios. It becomes, therefore, highly relevant to study whether this activity may pose concerns to the conservation of the environment in the areas where it takes place. Using a red-legged partridge (Alectoris rufa) shooting range as a study area, we examined the effect of intensive hunting on this species on the vegetation present. We found significantly higher lead levels in the sprouts of plants of shooting areas related to control sites of the same property where partridge shooting does not occur. We found differences in the presence of lead between sprouts of different plant species. In addition, old sprouts of existing vegetation in shooting areas also showed higher lead levels than newly emerged sprouts of the same plants. These results demonstrate the impact of lead ammunition on vegetation in terms of persistence over time and differences between species. Further analyses using chemical and ecotoxicological data are necessary to evaluate the extent of environmental pollution risks. Our results provide new support in favor of the use of alternative ammunition, with particular emphasis on scenarios where hunting activity is intensive.

Trace metals and metalloids in Andean flamingos (Phoenicoparrus andinus) and Puna flamingos (P. jamesi) at two wetlands with different risk of exposure in the Bolivian Altiplano

Birds are widely used as bioindicators in monitoring programs in wetlands. We compare concentrations of seven trace metals and metalloids (TMM) As, Cd, Cu, Fe, Hg, Pb, Znin both feathers and blood in two flamingo species in two high-altitude wetlands in Bolivia, with different levels of anthropogenic point source pollution. Lake Uru Uru (LUU) receives discharges from mining operations, and also effluents from the nearby city of Oruro, while Laguna Colorada (LCo) does not receive contaminants from anthropogenic sources. We sampled water and sediments at each site, as well as flamingos in three age classes in an effort to establish a benchmark for long-term monitoring. Metal concentrations in water did not differ between sites, whereas Zn and Pb concentrations of TMM in sediments were higher at LUU, and Hg higher at LCo. TMM concentrations were highly specific for all separate elements, but results point to differences between Andean flamingo (Phoenicoparrus andinus) chicks and the rest of the classes considered. As flamingo chicks did not molt before sampling, we pose that TMM concentrations in their blood and feathers may respond mainly to local conditions. Eggshells provide additional information, since adults transfer some TMM during egg development. Long-term monitoring in these species should include different age classes and sample both feathers and eggshells to monitor the environmental conditions and bioaccumulation of TMM in these species. Future studies should include sites devoid of natural sources of TMM to help distinguish sources of contamination, since some TMM (As and Pb) may be naturally in high concentrations in remote areas, like Laguna Colorada.

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.

Metals and trace elements in feathers: A geochemical approach to avoid misinterpretation of analytical responses

Assessing trace metal pollution using feathers has long attracted the attention of ecotoxicologists as a cost-effective and non-invasive biomonitoring method. In order to interpret the concentrations in feathers considering the external contamination due to lithic residue particles, we adopted a novel geochemical approach. We analysed 58 element concentrations in feathers of wild Eurasian Greater Flamingo Phoenicopterus roseus fledglings, from 4 colonies in Western Europe (Spain, France, Sardinia, and North-eastern Italy) and one group of adults from zoo. In addition, 53 elements were assessed in soil collected close to the nesting islets. This enabled to compare a wide selection of metals among the colonies, highlighting environmental anomalies and tackling possible causes of misinterpretation of feather results. Most trace elements in feathers (Al, Ce, Co, Cs, Fe, Ga, Li, Mn, Nb, Pb, Rb, Ti, V, Zr, and REEs) were of external origin. Some elements could be constitutive (Cu, Zn) or significantly bioaccumulated (Hg, Se) in flamingos. For As, Cr, and to a lesser extent Pb, it seems that bioaccumulation potentially could be revealed by highly exposed birds, provided feathers are well cleaned. This comprehensive study provides a new dataset and confirms that Hg has been accumulated in feathers in all sites to some extent, with particular concern for the Sardinian colony, which should be studied further including Cr. The Spanish colony appears critical for As pollution and should be urgently investigated in depth. Feathers collected from North-eastern Italy were the hardest to clean, but our methods allowed biological interpretation of Cr and Pb. Our study highlights the importance of external contamination when analysing trace elements in feathers and advances methodological recommendations in order to reduce the presence of residual particles carrying elements of external origin. Geochemical data, when available, can represent a valuable tool for a correct interpretation of the analytical results.

Lead from hunting activities and its potential environmental threat to wildlife in a protected wetland in Yucatan, Mexico

This study provides insights into the status of lead in the protected wetland of El Palmar, located on the northwestern littoral of the Yucatan Peninsula. This reserve is ecologically and economically important because it provides feeding and breeding habitats for many species, as well as being an ecotourism destination (especially for bird watching). Although it is a protected area, duck species are heavily hunted within the reserve during the winter. As a result, animals feeding or living in sediments could be exposed to anthropogenic lead. Total lead and its geochemical fractionated forms were measured in sediment cores from six selected sites in "El Palmar" wetland, during pre- and post-hunting seasons, to approximate the potential environmental threat (especially for benthonic living/feeding organisms). Anthropogenic lead concentrations detected in soil cores ranged from below the minimum infaunal community effect level (30.24 μg g(-1)) during the pre-hunting season, to bordering the probable infaunal community effect level (112.18 μg g(-1)) during the post-hunting season, according to SquiiRTs NOAA guidelines. Yet, these results were lower than expected based on the intensity of hunting. Consequently, this article explores the possibility that the lower than expected lead concentration in sediments results from (1) degradation of shot and transformation to soluble or particulate forms; or (2) ingestion of lead shot by benthic and other lacustrine species living in the protected area. Geochemical fractionation of lead demonstrated that in the top 6 cm of the soil column at heavily active hunting sites (EP5 and EP6), lead was associated with the lithogenic fraction (average 45 percent) and with the organic fraction (average 20 percent). Bioavailable lead (sum of lead adsorbed to the carbonates, Fe/Mn oxyhydroxides and organic fractions) in sediments was lower than 50 percent for the heavily active hunting areas and higher for the rest of the sites. Multivariate analysis showed that the environmental chemistry, the physicochemical characteristics of the water, and the geochemical qualities of the sediments do not favor the release of lead into the water column. Thus, the direct consumption of lead shot by organisms feeding in sea grass or in the top 10 cm of sediment is perhaps the major process preventing lead from being deposited in sediments, and, as such, these species (e.g., flamingos and/or ducks) could be threatened by anthropogenic lead pollution.

Lead concentrations in sediments and blue-winged teals (Anas discors) from El Palmar State Reserve, Yucatan, Mexico

Reserve regulations at El Palmar State Reserve, Yucatan, Mexico, prohibit the use of lead (Pb) shot, but hunters continue to use it, and no enforcement is implemented. Pb was quantified in sediments and in blue-winged teal Anas discors. No shot pellets were found in the sediment samples, nor were differences in sediment Pb concentrations observed within the reserve between popular hunting sites and those no longer used for hunting. However, there were differences between the hunting sites and sediments from an adjacent area where hunting is prohibited. Average Pb concentrations were highest at hunting entrances (15.69 ± 18.69 mg/kg) and lowest at decoy locations (5.24 ± 4.84 mg/kg). These averages are lower than the lowest effects level (31 mg/kg), although 10 samples exceeded this level. Pb-shot prevalence in gizzards was 4.88% (n = 41). Pb levels exceeded 5.0 mg/kg dry weight in one or more of the tested tissues (liver, gizzard, and bone) in 14 (34.14%; 7 female, 7 male; 11 adult, 3 juvenile) of the total birds. Bird weight, sex, and age had no effect on Pb concentration. Hunting using Pb shot in the reserve clearly affects Pb levels in sediments and in A. discors that winter there.

Animal poisoning in Europe. Part 3: Wildlife

This review article is the third in a series on animal poisoning in Europe and represents a collation of published and non-published wildlife poisoning data from Belgium, France, Greece, Italy and Spain over the last 10 years. Birds, particularly waterfowl and raptors, were more commonly reported as victims of poisoning than wild mammals. In addition to specific but important toxicological disasters, deliberate primary or secondary poisonings are of concern to all countries. Metals (particularly lead arising from sporting/hunting activities) and pesticides (mainly anticholinesterases and anticoagulants) are frequent causes of poisoning, and often have fatal consequences. A more unified and consistent approach throughout European countries to improve the reporting and the analytical confirmation of wildlife poisoning would help to reduce the number of cases of malicious or negligent animal poisoning.

Assessing the risk of lead exposure for the conservation of the endangered Pyrenean bearded vulture (Gypaetus barbatus) population

Acute and chronic lead (Pb) poisoning have been recognized as some of the most important causes of mortality for raptors worldwide. We simultaneously examined the recent, medium-term and long-term lead exposure of the endangered bearded vulture (Gypaetus barbatus) from the Pyrenees (northern Spain and southern France). One hundred and one blood samples from 87 captured individuals and tissue samples (liver and bone) from a further 43 dead individuals were analyzed for lead residues. The majority of individuals examined had very low lead concentrations in blood, liver and bone. However, two individuals showed elevated blood Pb levels, two individuals showed liver lead concentrations indicative of excessive lead exposure and one individual showed bone lead levels indicative of chronic lead poisoning, suggesting that the Pyrenean population is not free from the risk of poisoning. We found that Pb exposure was significantly higher in adult individuals as well as in the northern (France) and eastern (Catalonia) range of their distribution. These differences could be related to different feeding habits between age classes (pre-adults are more linked to supplementary feeding sites) and differences in hunting practices between regions (in some regions, carcasses and offal of game animals are not retrieved). Blood, liver and bone lead levels found were slightly higher during the hunting season than outside of the hunting season. Lead presents an unnecessary threat to adult birds and the only way to remove this risk is to ban all hunting with lead within the range of distribution of the endangered bearded vulture. Acute and chronic lead poisoning should be considered in differential diagnosis in any diseased or injured wild bearded vulture, especially subadult and adult individuals, and the potential risk of Pb poisoning should be considered in future reintroduction programs.