Widespread use of anticoagulant rodenticides in agricultural and urban environments. A menace to the viability of the endangered Bonelli's eagle (Aquila fasciata) populations.

Anticoagulant rodenticides (ARs) are one of the most toxic groups of compounds currently used worldwide for rodent pest control. Toxic baits are often, directly or indirectly, ingested by non-target animals, resulting in secondary poisoning and frequently affecting apex predators. Their presence in many species of raptors is quite common, particularly scavenger species, with some of these acting as sentinels for the presence of these substances in the environment. However, there is less data on the presence of ARs in Bonelli's eagle, one of the most endangered eagle species in Spain and which is experiencing a negative population trend in Europe. This medium-sized eagle feeds predominantly on live species, and rarely consumes carrion. In this study, 17 carcasses of Bonelli's eagles from the Eastern Spain were necropsied. Both first and second generation ARs in their livers were analyzed by HPLC-MS-TOF revealing that all the eagles studied had been exposed to at least 5 ARs, out of a total of 10 ARs analyzed, with 7 being the highest number of ARs detected in a sample. Second generation ARs were the most prevalent, particularly bromadiolone and brodifacoum, with the highest concentrations in 94% of the cases. More than a third of the eagles presented a liver concentration of greater than 200 ng/g ARs, suggesting AR poisoning. The elevated presence of these compounds in Bonelli's eagles could be a new cause of mortality for this species or could explain other causes of death, such as the increased mortality in power lines, and should be taken into account for their conservation. At the same time, the presence of these compounds in the environment also represents a risk to public health, as the most frequent species in the diet of Bonelli's eagle (rabbits and partridges) are also hunted and consumed by hunters and their families.

Development of a QuEChERS method for simultaneous analysis of antibiotics in carcasses for supplementary feeding of endangered vultures.

Antibiotics have been beneficial for human and animal health. However, an excessive use in livestock and a deficient management of the carcasses can lead to adverse effects in the scavengers that ingest them, especially in "supplementary feeding sites" (SFS). The aim of this study was to assess the potential risk of exposure to antibiotics for an endangered population of Cinereous vultures (Aegypius monachus) from southeastern Portugal. Hence, a multi-residue method based on QuEChERs was adapted and validated to analyse, in small volumes of tissues, the most frequent antibiotics used in livestock. The method was applied to 87 samples of liver, muscle and kidney from 7 goats and 25 sheep disposed in SFS. According to questionnaires to farmers, the animals had not been treated with antibiotics, but analyses showed residues in 29% of the samples. Antibiotics were more frequent in goats (42.9%) than in sheep (24.2%), and oxytetracycline and trimethoprim were the most common (both 13.8%). Oxytetracycline, the most common antibiotic for livestock in Portugal, showed the highest concentration (1452.68 ng g-1). To our knowledge, this is the first study of presence of antibiotics in carrion from SFS. The concentrations of antibiotics in carrion do not seem to pose a risk of acute intoxication for adult Cinereous vultures. However, subtle and likely chronic exposure with unknown health consequences may occur, which requires more research. Moreover, the results of this first study can be used in future studies to assess the risk for avian scavengers.

In vitro evaluation of cell death induced by cadmium, lead and their binary mixtures on erythrocytes of Common buzzard (Buteo buteo).

Cadmium and lead are persistent and ubiquitous metals that can cause several deleterious effects in living beings. Apoptosis and necrosis are two types of cell death that can be found after in vivo and in vitro exposure to these metals. In this study, isolated red blood cells from living captive Common buzzard (Buteo buteo) were exposed in vitro to different concentrations of lead, cadmium, and the mixture lead-cadmium in a proportion of 1:10 (similar to that found in previous field studies). Data obtained from dose-response curves were used to evaluate the interactive effects of metal mixtures on cell viability. In general, except for the exposure to NOEC, additivity was the most frequently observed response. As described in human, after in vitro exposure, lead was highly accumulated in buzzard erythrocytes, while cadmium accumulation was scarce. Finally, the type of cell death (apoptosis or necrosis) induced by the exposure to different concentrations of these heavy metals and their mixtures was evaluated in the red blood cells. Apoptosis was found to be the main type of cell death observed after cadmium and/or lead exposure. However, this exposure caused an increase in lysis or necrosis, especially if red blood cells were exposed to high doses.

A modification of QuEChERS method to analyse anticoagulant rodenticides using small blood samples

El uso de rodenticidas anticoagulantes es el método más frecuentemente utilizado para el control de plagas de roedores. Debido a sus características físico-químicas y particular mecanismo de acción, la utilización de estos compuestos en zonas rurales puede suponer un riesgo de intoxicación secundaria de sus depredadores. Para evaluar el riesgo a estos compuestos para la fauna silvestre, especialmente en aves rapaces que se alimentan de roedores, se llevan a cabo los programas de biomonitorización. Se ha desarrollado un método rápido, fácil y económico que permita el análisis de pequeños volúmenes de muestra de sangre. En el presente trabajo se han comparado tres diferentes modificaciones de la metodología "QuEChERS", y posteriormente uno de ellos fue elegido para la detección y cuantificación de estos compuestos. El proceso previo al análisis de los extractos incluye dos pasos sencillos: La muestra es extraída usando un solvente orgánico y una solución salina y, posteriormente, el sobrenadante es purificado usando una técnica de extracción en fase solida dispersiva. La detección y cuantificación de los rodenticidas anticoagulantes se realizó por cromatografía líquida acoplada a un detector de masas Agilent 1100 VL con trampa de iones y fuente de electrospray para ionización. La técnica finalmente elegida permite una recuperación entre 72-134% para los siete rodenticidas objeto de estudio (warfarina, cumatetralilo, difenacoum, clorofacinona, brodifacoum, bromadiolona, difacinona), la cual es superior a la obtenida con otras técnicas que analizan compuestos similares. Además, la sensibilidad de esta técnica es mayor a la que ofrecen otras técnicas. Con el fin de comprobar la utilidad de la técnica validada, se analizaron un total de 50 muestras de sangre de búho real (Bubo bubo) capturados en su hábitat natural (AU)

The use of anticoagulant rodenticides is the most common method to control rodent plagues. Due to their physicochemical characteristics and particular mechanism of action, the application of these compounds in rural areas can pose a risk of secondary poisoning for their predators. In order to evaluate the risk of these compounds for wildlife, especially raptors that feed on rodents, biomonitoring programmes are undertaken. A fast, easy and low cost technique was needed to analyse small volumes of blood samples. Therefore, three different modifications of QuEChERS methodology have been compared, and one of them selected to detect and quantify these compounds. The process prior to analysis of the extracts involves two simple steps: the sample is extracted and partitioned using an organic solvent and salt solution. The supernatant is then cleaned using a dispersive solid phase extraction (dSPE) technique. Detection and quantification of the anticoagulant rodenticides were performed by LC-MSMS on an Agilent 1100 VL Series ESI/LC/MSD, with an electrospray ionisation (ESI) source and ion trap analyser. The method finally chosen provides a 72-134% recoveries for the seven rodenticides (warfarin, coumatetralyl, brodifacoum, bromadiolone, difenacoum, chlorophacinone, diphacinone), higher than in other methods to analyse similar compounds. Sensitivity of our method is also higher than in other methods. In order to prove the utility of the technique, a total of 50 blood samples of free-living Eagle owls (Bubo bubo) were analysed (AU)

Blood lead levels and δ-ALAD inhibition in nestlings of Eurasian Eagle Owl (Bubo bubo) to assess lead exposure associated to an abandoned mining area.

In order to biomonitor lead contamination in Southeastern Spain, 218 blood samples from 28 to 30-day old Eurasian Eagle Owl chicks (Bubo bubo) born between 2003 and 2007 were analysed. In general, mean lead levels showed that chicks were exposed to background concentrations. However, mean levels in chicks born in an ancient and abandoned mining site ("Sierra Minera Cartagena-La Union") or in their surroundings (Geometric mean (GM) = 5.83 µg/dl, range 0.49-25.61 µg/dl), an area highly polluted by lead and other metals, were significantly higher (p < 0.001) than the rest of the population (GM = 1.66 µg/dl, range = Non detected-18.37 µg/dl). Because δ-ALAD activity is considered the best biomarker for lead exposure and effect in birds, the activity of this enzyme was also evaluated and correlated with lead levels in blood. In this study, low levels of blood lead inhibited δ-ALAD, even when lead concentrations were lower than the limits described by other authors in raptors. Adverse effects caused by this inhibition may occur when blood lead levels were above 15 µg/dl, although only eight chicks presented these concentrations in their blood. Sampling site also influenced enzymatic activity, since it decreased about 60% in the polluted area in relation to the rest. For all these reasons, further research regarding risk assessment for lead exposure in Eagle Owls nesting in the polluted area is advisable. Our results suggest that the Eurasian Eagle Owl can be considered a suitable sentinel animal for monitoring lead contamination and δ-ALAD activity can be used as a sensitive biomarker for lead exposure and effect in this species.

Desarrollo de método analítico para la extracción de plaguicidas organoclorados en plumas / Development of an analytical method for extracting organochlorine pesticides from feathers

Debido a los efectos adversos de los plaguicidas organoclorados (OC), estos compuestos han sido monitorizados en diferentes especies de seres vivos. En estos estudios de biomonitorización ambiental, las aves han jugado un importante papel debido a su sensibilidad a los cambios ambientales y a su elevada posición en la cadena trófica. En los últimos años existe un interés creciente en utilizar muestras no destructivas como alternativa a los tejidos internos. En este sentido, las plumas han sido ampliamente utilizadas en la monitorización de la contaminación ambiental por metales pesados y podrían proporcionar información de la concentración de OC en la sangre durante su desarrollo. Sin embargo, la información sobre su uso en la monitorización de OC es escasa. El objetivo general del presente estudio es comprobar la utilidad de la pluma como unidad de biomonitorización de la exposición a plaguicidas organoclorados. Para ello se desarrolla un método de extracción de 16 OC en plumas, incluyendo α-, β- y δ-HCH, lindano, aldrín, dieldrín, endrín, endrín aldehído, endosulfán I y II, endosulfán sulfato, p,p’-DDT, DDD, DDE, heptacloro y su epóxido. Además se evalúa la interferencia por contaminación externa en los niveles encontrados en plumas y se estudia la distribución de los compuestos entre partes de la pluma (barbas y ejes).La contaminación externa parece tener influencia en los niveles encontrados en plumas para determinados compuestos, sin embargo, no parece ser la única causa de los mayores niveles observados en barbas en comparación con los ejes.La pluma parece ser una prometedora herramienta no destructiva de plaguicidas organoclorados en aves. Futuros estudios deben ir encaminados en determinar correlaciones entre concentraciones en plumas y tejidos internos de aves. Además, se deben evaluar factores adicionales como la edad, sexo y estado nutricional de las aves para comprobar su efecto sobre los niveles de contaminantes en plumas(AU)

Due to the adverse effects of organochlorine pesticides (OC), these compounds have been widely monitored in several species of living beings. Birds have played an important role in monitoring environmental pollution due to their sensitivity to environmental changes and their position in the upper of the food chain. In recent years, many efforts have been attempted to look for useful samples obtained in a non-destructive way as alternative to the collection of internal tissues. Feathers can provide information of OC concentrations in the circulating blood at the time of their development. They have been widely used in monitoring of metal environmental pollution. However, information about their use in OC monitoring is scarce. The general aim of this study is the validation of the feather as OC biomonitoring tool. In this sense, we develop a method of extraction for 16 OC in feathers, including α-, β-and δ-HCH, lindane, aldrin, dieldrin, endrin, endrin aldehyde, endosulfan I and II, endosulfan sulfate, p,p’-DDT, DDD, DDE, heptachlor and its epoxide. Moreover, we assess the influence of external contamination and the distribution of compounds between parts of the feather (barbs and shaft).External contamination seems to have influence on the levels found in feathers for some compounds. However, it does not seem to be the only cause of the high levels observed in barbs in comparison with those detected in shaft.Feather could be considered as a promising non-destructive tool for organochlorine pesticides in birds. Future studies should be carried out to obtain correlations between concentrations in feathers and internal tissues of birds. Moreover, it is necessary to evaluate additional factors such as age, sex and nutritional status of the birds in order to check its effect on the OC levels in feathers(AU)

Blood delta-ALAD, lead and cadmium concentrations in spur-thighed tortoises (Testudo graeca) from Southeastern Spain and Northern Africa.

Mediterranean spur-thighed tortoise (Testudo graeca) is actually included in the IUCN as vulnerable species. Its main European population is located in southeastern Spain. Although a great deal of information has been acquired on the internal medicine and survey and even parasitological fauna on these animals, there are no references about contaminants levels in this species. The objectives of this study were to compare the levels of two metals (cadmium and lead) in the blood of spur-thighed tortoises from two different populations, one from Southeastern of Spain (n = 22) and the other from North of Africa (n = 39), kept in captivity at the Santa Faz Recuperation Centre (Alicante, Spain) and to investigate the relationship between their blood levels of lead and their blood delta-aminolevulinic acid dehydratase (delta-ALAD) activity. Blood lead and cadmium concentrations were higher in tortoises from African than in those from Spain. Moreover, a negative and significant correlation (P < 0.05) was found between delta-ALAD activity and blood lead levels, indicating the suitability of this enzyme as biomarker for lead in this species.

Alteraciones anatomo-patológicas en un flamenco común (phoenicopterus roseus) por intoxicación aguda por plomo / Pathological alterations in the common flamingo (Phoenicopterus roseus) due to acute lead intoxication

La presencia de plomo en el medio ambiente es un hecho indiscutible. Ello es objeto de gran interés sanitario pues repercute tanto en la salud de los animales como en la del ser humano. El plumbismo es una intoxicación que puede afectar a cualquier especie animal. En el ámbito de la fauna silvestre se asocia principalmente a la actividad cinegética en los humedales y a la ingestión de plomo metálico por parte de las aves que frecuentan estos ecosistemas. En España cada año mueren decenas de miles de aves acuáticas como consecuencia de la ingesta de perdigones de plomo. En los individuos capturados enfermos se pueden observar signos clínicos, mientras que a partir de muestras de cadáveres se obtienen datos sobre niveles tisulares de plomo. Sin embargo la evaluación de lesiones anatomo-patológicas en animales de vida silvestre es difícil de realizar por la dificultad de encontrar animales recién muertos o afectados de un cuadro agudo mortal. La reproducción de esta patología en animales de experimentación se suele realizar en cisnes, palomas o patos, pero no en flamencos, por lo que no es usual disponer de datos histológicos en esta especie. En este trabajo presentamos la clínica, analítica y estudio microscópico de diferentes tejidos de un flamenco común (Phoenicopterus roseus) muerto por plumbismo(AU)

The presence of lead in the environment is an undisputable fact. Furthermore, it is a serious health concern as it affects not only the well-being of animals, but also that of human beings. Plumbism is a type of intoxication that can affect any animal species. In wild fauna, it is mostly associated with cynegetic species in wetlands and the ingestion of metallic lead by birds which frequent these ecosystems. In Spain, tens of thousands of water birds die each year as a result of ingesting lead pellet. Clinical signs may be observed in captured, sick individuals, whilst data regarding lead tissue levels are obtained from samples derived from cadavers. However, the evaluation of pathoanatomical lesions in wildlife is problematic due to the difficulty of finding recently deceased animals or those affected by terminally acute manifestations. The reproduction of this pathology in experimental animals is usually performed in swans, pigeons or ducks, not in flamingos and as such, histological data from this species is not commonly available. In this paper, we present the clinical, analytical and microscopical study of tissues derived from common flamingos (Phoenicopterus roseus) having died of plumbism(AU)

Aspectos clínicos y forenses del envenenamiento de aves silvestres: diferencias entre aldicarb y estricnina / Clinical and forensic aspects of the poisoning of wild birds: differences between aldicarb and strychnine

Aldicarb y estricnina son frecuentemente usados para envenenar fauna silvestre y doméstica. La estricnina se utilizó ampliamente hace algunos años hasta que fue prohibido su uso en 1994, siendo sustituida por otros plaguicidas carbamatos como el aldicarb o el carbofurano. En los últimos años se ha producido un aumento de envenenamientos por estricnina. Los síntomas de la intoxicación por estricnina y carbamatos están ampliamente descritos en mamíferos, pero no en aves. En la mayoría de los casos forenses la única información disponible es el análisis químico-toxicológico del cadáver o del cebo. Esta carencia de información es debida, en gran medida, a un inadecuado manejo y procesado de la escena del crimen, la inadecuada formación de los agentes para tomar y embalar las muestras, y/o la falta de formación toxicológica y/o forense de los veterinarios. La escena del crimen es solo uno de los componentes de la investigación pero necesita ser coordinada con los otros aspectos de la investigación. La escena del crimen debe ser estudiada hasta el más mínimo detalle para establecer un correcto diagnóstico. En este trabajo, utilizando como referencia el envenenamiento por aldicarb y estricnina, enfatizamos algunos aspectos clínicos y forenses que deben ser tenidos en cuenta en la investigación del envenenamiento de aves silvestres

Aldicarb and strychnine are frequently used to poison wild and domestic animals. Strychnine was widely used until it was banned in 1994, being substituted for carbamates such as aldicarb or carbofuran. Recently, an increase of deliberated poisonings using strychnine has been observed. Symptoms of aldicarb and strychnine poisonings have been widely described in mammals, however they have been poorly reported in birds. In most forensic cases the only available data is the chemical analysis realized on baits or tissues from dead animals. This scarcity of information is due usually to an inadequate management and processing of the crime scene, an unsuitable training of the first officer to collect and package the physical evidences, and/or unsuitable toxicological and forensic training of the veterinarians. Is should be recognized the crime scene is only one component of an investigation and needs to be coordinated with other aspects of the investigation. The crime scene should be investigated down to the last detail in order to establish an accurate diagnosis. In this work, using aldicarb and strychnine poisonings as references, we emphasize some clinical and forensic aspects which should be taken into account in the investigation of poisoning of wild birds

High levels of blood lead in griffon vultures (Gyps fulvus) from Cazorla Natural Park (southern Spain).

The blood lead of 23 griffon vultures (Gyps fulvus) trapped in 2003 was analyzed in order to evaluate exposure to lead in the vulture population of Cazorla Natural Park (in southern Spain). In 2001 the use of leaded gasoline in vehicles was banned in the European Union; however, lead ammunition is still used in Spain in big-game hunting for red deer, fallow deer, mouflon, and wild boar, which are ingested by vultures from September to March. The mean concentration of lead in blood was 43.07 +/- 31.96 microg/dL with a range of 17.39-144.80 microg/dL. Only two vultures had lead levels below 20 microg/dL, and two others had blood lead concentrations close to 150 microg/dL. In view of the results, we think the population of vultures from Cazorla Natural Park is suffering subclinical exposure to lead, with some individuals exposed to high toxicity risk. We concluded that ingestion of lead in the metallic form alone is sufficient to produce these blood lead concentrations, and we recommend the prohibition of lead ammunition for big-game hunting in order to preserve the vulture population.

Lead in feathers and delta-aminolevulinic acid dehydratase activity in three raptor species from an unpolluted Mediterranean forest (Southeastern Spain).

This paper presents the levels of lead found in the feathers of adult and blood of nestlings of booted eagle (Hieraaetus pennatus), European buzzard ( Buteo buteo), and goshawk (Accipiter gentilis) sampled in the 1999 and 2000 breeding seasons in a Mediterranean forest of the Province of Murcia (Southeastern Spain) located far from potential sources of metal contamination. Levels of delta-aminolevulinic acid dehydratase activity (delta-ALAD) in blood were also measured in the nestlings. Lead concentrations ranged from 1.1 to 11.21 microg/dl in blood of nestlings and from 0.35 to 1.66 mg/kg d.w. in the feathers of their parents. A significant relationship was found between blood delta-ALAD and lead (rho = -568), showing a negative correlation with blood lead levels even at lead concentrations below 5 microg/dl. This fact suggests the usefulness of this enzymatic biomarker for low lead exposure in forest raptors. There were also positive relationships between the lead concentrations in blood of nestlings and those in feathers of their parents (rho = 0.817), suggesting the usefulness of feathers for biomonitoring environmental exposure to lead.

Pluma de Aguila Calzada (Hieraaetus pennatus) como unidad biomonitora de la exposición de la ambiental a cadmio y plomo / Feather of Booted Eagle (Hieraaetus pennatus) as biomonitor of environmental exposure to cadmium and lead

La determinación de plomo y cadmio en sangre y tejidos de aves rapaces permite obtener información útil sobre el estado de salud de los individuos, de la especie y del medio ambiente en el que viven. Además su medición sistemática en programas de toxicovigilancia facilita la predicción de riesgos y la toma de decisiones de gestión medioambiental. El presente trabajo tiene como objetivo valorar la utilidad de la pluma de aves rapaces como unidad de monitorización de la exposición a metales pesados (cadmio y plomo) en un ambiente considerado a priori como mínimamente contaminado de la Región de Murcia (Sierras de Lavia y Burete, NO de Murcia). Para ello se han tomado muestras de sangre de pollos y plumas de adultos de águila calzada (Hieraaetus pennatus) durante la época de cría de los años 1999 y 2000. Previo al análisis de metales en plumas fue preciso optimizar una técnica de lavado de las muestras capaz de eliminar los metales depositados en su superficie. Todas las muestras de sangre, excepto dos, tenían niveles de cadmio y plomo inferiores a 0,5 y 5 microg/dl, respectivamente, lo que es compatible con situaciones de contaminación ambiental de fondo. Las concentraciones en plumas fueron muy inferiores a las indicativas de efecto, con medias de 16,5 y 750 microg/kg para cadmio y plomo, respectivamente. Las correlaciones entre las concentraciones de ambos metales en sangre y plumas fueron significativas al nivel p< 0,05 para el cadmio y de p <0,01 para el plomo. En conclusión opinamos que la determinación de cadmio y plomo en pluma de águila calzada es útil en los estudios de biomonitorización y toxicovigilancia. (AU)

Residuos de insecticidas organoclorados encernícalo común (Falco tinnunculus) de la región de Murcia / Residues of organochlorine insecticides in European kestrels (Falco tinnunculus) from Murcia Region

La Región de Murcia es una zona eminentemente agrícola donde el uso de plaguicidas, incluyendo los organoclorados, ha sido y es aún muy intenso. El uso de la mayoría de los insecticidas organoclorados ha sido restringido o prohibido, sin embargo, su alta persistencia en el medio ambiente y su capacidadd de bioacumulación justifican aún su presencia en los seres vivos. El uso de aves silvestres como biomonitores de la contaminación ambiental se ha extendido en los últimos años, destacando las rapaces por la trascencencia que exposiciones a estos compuestos pueden tener sobre su éxito reproductivo. Para este trabajo hemos elegido al cernícalo vulgar (Falco tinnunculus) como especie biomoitora por varias razones: por su situación en las partes altas de la cadena trófica; porque en su alimentación forman parte importante los insectos y otros invertebrados, objeto diana del uso de estos productos; por su relativa abundancia con respecto a otras rapaces en la Región de Murcia: porque la mayoría de cernícalos que residen en la Región de Murcia lo hacen durante todo el año; y por su posible utilidad como indicador del grado de exposición del cernícalo primilla (Falco naumanni), especie en regresión en la Península Ibérica. Se han estudiado los niveles de residuos de un total de 15 compuestos organoclorados en tejidos (hígado, encéfalo y grasa) de 29 cernícalos vulgares. Casi todos los cernícalos muestreados presentaron en los tres tejidos analizados residuos de p,p´-DEE, endrín, d-HCH y heptacloro; y un alto porcentaje presentó residuos de lindano (50 por ciento) y endosulfán (60 por ciento). La presesncia de residuos de a-HCH, B-HCH, aldrín, dieldrín, heptacloro epóxido p,p´-DDD fue muy baja (<20 por ciento). Las concentraciones más altas correspondieron al p,p´-DDE (concentración media total de 0.95 mg/kg), seguido del endrín (concentración media total =0.3 mg/kg) y del d-HCH (concentración media de 0.12 mg/kg). Las concentraciones medias totales del resto de organoclorados fueron inferiores a 0.1 mg/kg. Los resultados revelaron una baja exposición a este tipo de compuestos probablemente como resultado de la aplicación de plaguicidas alternativos tras las prohibiciones de uso de los organoclorados en la década de los 80 con la consiguiente disminución de los niveles de éstos en el medio ambiente. Se ha observado un aumento de las concentraciones con la edad. (AU)

Sunflower meal as cause of chronic copper poisoning in lambs in southeastern Spain.

Sunflower meal with a copper/molybdenum ratio of 10 caused copper toxicosis in lambs. Copper must be analyzed on a dry matter basis in liver and renal cortex. Oral administration of molybdenum and thiosulfate had a certain effectiveness in sick animals. Care must be taken with feedstuffs made from copper-dependent plants.

Environmental exposure and distribution of lead in four species of raptors in Southeastern Spain.

The purpose of this study was to monitor exposure to lead in four species of raptors in Southeastern Spain (Murcia Region). Samples of liver, kidney, brain, blood, and bone from two species of diurnal raptors (European kestrel (Falco tinnunculus) and European buzzard (Buteo buteo)) and two species of nocturnal raptors (Eagle owl (Bubo bubo) and Little owl (Athene noctua)) were obtained during 1994. Relationships were found between size and age of the birds, the nearness to areas of human activity and lead concentrations in tissues. The lead distribution pattern reveals that the bone is the principle organ for accumulation (0.62-43 mg/Kg, dry weight), followed by the kidney (0.03-0.66 mg/Kg, wet weight), and liver (0. 017-0.05 mg/Kg, w.w.), and to lesser extent, the brain (0.013-0.223 mg/Kg, w.w.). This distribution pattern indicates that raptors in Southeastern Spain were exposed to environmental low lead levels continuously over an extended period of time. Correlations between lead in bone and lead in soft tissues were higher in European buzzards (r = 0.87-0.95) and Eagle owl (r = 0.71-0.86) than those found in European kestrels (r = 0.53-0.58) and Little owls (r << 0). However, correlations between lead concentrations in soft tissues and in blood were high (r = 0.85-0.99).