Pb, Cd, As, and Se concentrations in livers of dead wild birds from the Ebro Delta, Spain

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.

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.

Lead exposure does not affect baseline and induced innate immunity in quails

Lead (Pb) is one of the most common metals found in ecosystems in elevated concentrations derived mainly from anthropogenic activities. Pb toxicity is of special concern in birds due to its capacity for bioaccumulation in the liver, bones, and kidneys causing physiological disruptions. Such disruptions can be lethal in a few days after Pb acute intoxication and they are associated with several million deaths of birds. Moreover, Pb may work as an immunosuppressant as it affects the cell-mediated and humoral immune responses, including components of the acute-phase response (APR). We (1) examined the effects of Pb contamination on the innate immune system, body mass, and food intake of Japanese quails (Coturnix coturnix japonica), and (2) evaluated the effects of Pb on its APR after exposing the animals to Pb acetate in drinkable water during 7 days. We found that Pb contamination increased the number of circulating white blood cells (WBCs), but no effect was found on body mass, food intake, the heterophil/lymphocyte (H/L) ratio, and haptoglobin (Hp) concentration. When Pb-exposed birds were injected with lipopolysaccharide from Escherichia coli to activate the APR, they had a negative body mass ratio, reduced food intake, and increased the number of WBCs, the H/L ratio, and the Hp concentration. We conclude that Pb exposure at this dose did not affect baseline values of the constitutive response and that it did not affect the APR of quails, but commend for further studies testing the effect of different Pb doses.

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.

Economic assessment of wild bird mortality induced by the use of lead gunshot in European wetlands

In European wetlands, at least 40 bird species are exposed to the risk of lead poisoning caused by ingestion of spent lead gunshot. Adopting a methodology developed in North America, we estimated that about 700,000 individuals of 16 waterbird species die annually in the European Union (EU) (6.1% of the wintering population) and one million in whole Europe (7.0%) due to acute effects of lead poisoning. Furthermore, threefold more birds suffer sub-lethal effects. We assessed the economic loss due to this lead-induced mortality of these 16 species by calculating the costs of replacing lethally poisoned wild birds by releasing captive-bred ones. We assessed the cost of buying captive-bred waterbirds for release from market surveys and calculated how many captive-bred birds would have to be released to compensate for the loss, taking into account the high mortality rate of captive birds (72.7%) in the months following release into the wild. Following this approach, the annual cost of waterbird mortality induced by lead shot ingestion is estimated at 105 million euros per year in the EU countries and 142 million euros in the whole of Europe. An alternative method, based upon lost opportunities for hunting caused by deaths due to lead poisoning, gave similar results of 129 million euros per year in the EU countries and 185 million euros per year in the whole of Europe. For several reasons these figures should be regarded as conservative. Inclusion of deaths of species for which there were insufficient data and delayed deaths caused indirectly by lead poisoning and effects on reproduction would probably increase the estimated losses substantially. Nevertheless, our results suggest that the benefits of a restriction on the use of lead gunshot over wetlands could exceed the cost of adapting to non-lead ammunition.

Reproductive effects in hybrid sparrow from a polluted area in Tunisia: Oxidative damage and altered testicular histomorphology

Air pollution is a threat for human health and wildlife. The aim of this study is to assess the pathophysiological changes and the oxidative-antioxidative status in testicular tissues of 40 Hybrid sparrows collected from four areas in Gabès city, one of the most polluted areas in Tunisia. The testis histopathological analysis revealed alterations in birds from Ghannouche, the polluted area. The thiobarbituric acid reactive substance (TBARS) levels were higher in testis of birds from the contaminated site compared to less polluted areas indicating oxidative damage to membrane lipids. Antioxidant enzyme activities (superoxide dismutase and catalase) were lower in testis sparrows from the polluted site compared with the reference site, suggesting deficiency of the antioxidant system to compensate for oxidative stress. Overall, our results suggest that the hybrid sparrow offers a suitable model for biomonitoring programs of atmosphere pollutants and the selected biomarkers could be useful tool to evaluate pollution impacts in living organisms.

Assessment of the exposure to heavy metals in Griffon vultures (Gyps fulvus) from the Iberian Peninsula

Griffon vultures (Gyps fulvus), by virtue of their position at the top of the food chain and as obligate scavengers, are at risk of accumulating and concentrating heavy metals in their tissues and may be more predisposed to their toxic effects. The aim of this study is to investigate heavy metal concentrations in Griffon vultures in Portugal and Catalonia, Spain and to determine if heavy metal concentrations in the blood of weak and/or injured Griffon vultures admitted to wildlife rehabilitation centres (WRC) reflect contamination profiles in the local, free-living and outwardly healthy population. Whole-blood samples taken from 121 Griffon vultures caught in the wild or admitted to WRC in Portugal and Catalonia, Spain were examined for cadmium (Cd), mercury (Hg) and lead (Pb) by inductively coupled plasma mass spectrometry (ICP-MS). Cd and Hg were not detected in most samples (98.3% and 95%, respectively), while Pb was detected in all birds in concentrations ranging between 4.97 and 300.23 µg/dl. Birds admitted to WRC had significantly lower Pb concentrations (24.15 ± 15.07 and 25.98 ± 18.04 µg/dl in Portugal and Catalonia, Spain, respectively) than animals caught in the wild (29.67 ± 13.19 and 42.22 ± 50.08 µg/dl in Portugal and Catalonia, Spain, respectively) (p<0.05). This may be explained by the fact that malnutrition was the main cause of admission of Griffon vultures to WRC, as ingestion has been described as the most significant pathway for Pb exposure in raptors. Therefore Griffon vultures admitted to WRC do not seem to be representative of the local, free-flying populations, so it remains necessary to continue catching when one intends to monitor Pb exposure in this species. The population of vultures captured in Catalonia, Spain showed the highest mean blood Pb concentration, perhaps due to the municipal rubbish dump located near the feeding station, with rubbish providing a significant fraction of their trophic needs. The ingestion of game meat with bullet fragments in carcasses or with Pb shots embedded in their flesh could also be the cause of the high blood Pb concentrations found in some vultures. The potential risk of Pb exposure in Griffon vulture populations must be given consideration, since most individuals evaluated had Pb concentrations between 20 and 100µg/dl, which is considered to be subclinical exposure to Pb, and which is above the threshold level at which Pb can affect antioxidant system in this species (15 µg/dl).

Distribution of persistent organochlorine chemical residues in blood plasma of three species of vultures from India

The presence of persistent organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in blood plasma of white-backed vulture Gyps bengalensis, Egyptian vulture Neophron percnopterus, and griffon vulture Gyps fulvus collected from Ahmedabad, India. All the samples had varying levels of organochlorine pesticides and PCBs. Statistically significant (P<0.05) differences among species were detected for beta-hexachlorocyclohexane (β-HCH), ∑HCH, and dichloro-diphenyl-trichloroethane (DDT). The mean concentration of ∑HCH, ∑DDT, and ∑PCBs among plasma ranged from 43.7 to 136, 8.8 to 64.8, and 226 to 585 ng/ml, respectively. Among the various OCPs analyzed, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) was detected most frequently. The concentrations of cyclodiene insecticides detected were lower than the other organochlorine residues. The levels of pesticides measured in plasma samples of three species of vulture were comparable to the results documented for a number of avian species and were lower than those reported to have deleterious effects on survival or reproduction of birds. Although no threat is posed by any of the organochlorine pesticides detected, continuous monitoring of breeding colonies is recommended. This study is also the first account of a comprehensive analysis of toxicants present in blood plasma of vulture species in India. The values reported in this study can serve as guidelines for future research in general as well as control values during the analysis of samples obtained from birds in the event of suspected organochlorine poisoning.

Persistent organochlorine pesticide residues in tissues and eggs of white-backed vulture, Gyps bengalensis from different locations in India

Organochlorine pesticide residues were determined in tissues of five Indian white-backed vultures and two of their eggs collected from different locations in India. All the samples had varying levels of residues. p,p'-DDE ranged between 0.002 microg/g in muscle of vulture from Mudumali and 7.30 microg/g in liver of vulture from Delhi. Relatively higher levels of p,p'-DDT and its metabolites were documented in the bird from Delhi than other places. Dieldrin was 0.003 and 0.015 microg/g while p,p'-DDE was 2.46 and 3.26 microg/g in egg one and two respectively. Dieldrin appeared to be lower than the threshold level of 0.5 microg/g. p,p'-DDE exceeded the levels reported to have created toxic effects in eggs of other wild birds. Although varying levels of DDT, HCH, dieldrin, heptachlor epoxide and endosulfan residues were detected in the vulture tissues, they do not appear to be responsible for the present status of population in India.

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

Waterbirds are exposed to many contaminants, including lead from ingestion of shot and fishing sinkers. Lead poisoning had never been reported in flamingos wintering in Italian wetlands. Our investigation stems from a case of four flamingos found dead in Tuscany in 2002 with numerous lead shot in their gizzards. We therefore considered other specimens found dead in different Italian wetlands. Many lead shot found in gizzards and lead tissue concentrations confirmed the hypothesis of lead poisoning in two of the seven specimens analysed: concentrations in liver, kidney, and bone were 361.3, 265.09, and 43.31mug/g d.w., respectively. Lead organotropism was typical of acute poisoning. Cadmium and mercury were also determined, and found to be in line with what little data are available on this species in the literature. Although Italy recently endorsed the African-Eurasian Waterbird Agreement (AEWA) prohibiting use of lead shot for hunting in wetlands, our results reveal a first case of lead shot poisoning in flamingos wintering in Italian wetlands. This evidence sounds a further warning of the problem of spent lead shot in countries where hunting in wetlands is not strictly regulated.

Heavy metal distribution in chicks of two heron species from Korea

This study presents concentrations of iron, manganese, zinc, copper, lead, and cadmium in tissues of black-crowned night heron (Nycticorax nycticorax) (n = 8) and grey heron (Ardea cinerea) (n = 9) chicks from Pyeongtaek heronry, Gyeonggi-do, Korea, 2001. Iron (respectively, 45.8 +/- 24.0 microg/wet g, 155 +/- 123 microg/wet g), zinc (38.3 +/- 5.34 microg/wet g, 50.9 +/- 14.0 microg/wet g), and copper (9.93 +/- 2.26 microg/wet g, 30.2 +/- 12.9 microg/wet g) concentrations in feathers, manganese concentrations in livers (3.26 +/- 0.68 microg/ wet g, 1.50 +/- 0.58 microg/wet g), kidneys (1.43 +/- 0.27 microg/wet g, 0.84 +/- 0.34 microg/wet g), and bones (1.34 +/- 0.50 microg/wet g, 3.17 +/- 1.31 microg/wet g) were different between black-crowned night heron and grey heron chicks. Lead concentrations in bones (0.11 +/- 0.04 microg/wet g, 0.61 +/- 0.42 microg/wet g) and cadmium concentrations in liver (13.5 +/- 2.30 microg/wet kg, 10.3 +/- 1.59 microg/wet kg), kidney (6.61 +/- 2.54 microg/wet kg, 2.31 +/- 1.29 microg/wet kg), and muscle (5.25 +/- 5.91 microg/wet kg, 1.37 +/- 0.90 microg/wet kg) differed between chicks of the two heron species. The differences of heavy metal concentrations in tissues in herons and egrets were reported to other similar studies. Heavy metal concentrations for both heron species were at background levels. In both species, lead concentrations were higher in livers than in bones and cadmium concentrations were higher in livers than in kidneys. We suggest that it is not chronic exposure but acute exposure to lead and cadmium contamination around breeding site that leads to these observations. Therefore, lead and cadmium concentrations in tissues can be used as a bioindicator of acute local contamination.

Heavy metal concentrations in diet and livers of Black-crowned Night Heron Nycticorax nycticorax and Grey Heron Ardea cinerea chicks from Pyeongtaek, Korea

This study presents concentrations of iron, manganese, zinc, copper, lead and cadmium in diet and livers of Black-crowned Night Heron Nycticorax nycticorax and Grey Heron Ardea cinerea chicks from Pyeongtaek, Gyeonggi-do, Korea. Heavy metal concentrations of heron chicks were not related to concentrations in the diet. Copper concentrations were significantly greater in the diet of Black-crowned Night Herons (geometric mean = 13.6 wet microg/g) than Grey Herons (7.45 wet microg/g), other metal concentrations did not differ between the diet of two species. Manganese (respectively 3.20 wet microg/g, 1.41 wet microg/g) and cadmium (respectively 13.4 wet microg/kg, 1.41 wet microg/kg) concentrations were higher in livers of Black-crowned Night Heron chicks than Grey Heron chicks, but zinc, iron, copper and lead concentrations in livers did not differ in between two herons. The essential elements were at background levels, however copper concentrations were relatively higher than previously reported from Korea. Lead and cadmium concentrations were within background levels for herons.

Accumulation of heavy metals and As in wetland birds in the area around Doñana National Park affected by the Aznalcollar toxic spill

The impact of the spill from the mine in Aznalcollar (Seville, Spain) on waterfowl in the Doñana National Park is assessed. The concentrations of Cu, Pb, Cd, Zn nd As in the liver and eggs of 16 species of waterfowl found dead in the Park between April and November 1998 were determined. The highest levels were found for Zn, followed by Cu, Pb, Cd and As. The main parameters related to the accumulation of these elements in the waterfowl studied were species and trophic level. The other variables studied--distance from the spill, days of exposure, sex, size, and age--are important, although this depends on the element studied. Zn and Cu from the spill have entered the food chain of the aquatic birds studied, but Cd, Pb and As have not. There is currently no evidence to suggest that the trace element concentrations measured have reached toxic levels.