Use of poisoned baits against wildlife. A retrospective 17-year study in the natural environment of Extremadura (Spain).

This study reports the results obtained from toxicological analyses of different types of baits referred to the laboratory of the Toxicology Area (Faculty of Veterinary Medicine, Cáceres, Spain) over a 17-year period (2002-2018). These baits were suspicious materials found in the environment of the region of Extremadura (Western Spain), where such malpractices are a problem to be addressed, as wide livestock farming and hunting activities are combined with a significant wealth of wildlife (especially birds of prey). A total of 246 baits, including 32 commercial chemical products to be used in baits, were analysed. Samples from 183 cases were received and classified according to the material used for their preparation and the toxic substance found. Overall, the most common bait consisted of meat preparations (56.3% of cases) intended to eliminate predators considered 'annoying' for livestock and hunting practices, such as carnivores and scavengers. It should be noted that contact baits (as fenthion-impregnated perches) were also detected (7.6%). Regarding the substances detected, anticholinesterase compounds (organophosphates and carbamates) were the most commonly used substances for the preparation of baits (detected in 85.3% of positive baits). Moreover, 8% of the positive baits presented more than one toxic substance in their composition. Due to the types of toxic compounds and the methods used to prepare the baits, this study shows that the malicious use of highly toxic substances in the environment to kill wildlife is a common and current issue and poses a serious risk to different species.

Brain biomarkers in tench ( Tinca tinca L.) after semi-static exposure to the pesticide carbofuran / Biomarcadores cerebrales en tenca (Tinca tinca L.) tras una exposición semiestática al pesticida carbofurano / Biomarcadores cerebrais na tenca (Tinca tinca L.) após uma exposição semi-estática ao pesticida carbofurano

Abstract Background: The aquatic environment is continuously being contaminated with toxic chemical substances from industrial, agricultural and domestic activities. The identification of different biomarkers of such contamination is of great relevance to determine the potential impact of those xenobiotics on the health of organisms. Objectives: To estimate the suitability of different biochemical brain biomarkers from tench in order to evaluate the environmental effect of an exposition to different concentrations of the pesticide carbofuran. Methods: The present study focused on the effect of a long-term exposure (28 days) to different concentrations (50, 100 and 200 μg/L) of the pesticide carbofuran on certain biochemical parameters of tench (Tinca tinca L.). Selected biomarkers for stress monitoring were malondialdehyde (MDA), as index of lipid peroxidation, and reduced glutathione (GSH). Moreover, acetylcholinesterase (AChE) activity was quantified as biomarker of effect on fish nervous system. Results: AChE activity was significantly inhibited in fish exposed to all concentrations of carbofuran after 14 and 21 days of exposure, returning to basal levels after this period with 50 and 100 μg/L. Moreover, significant decreases of MDA levels could be detected after 14 and 21 days of exposure to 200 μg/L, lasting until the end of the experiment. GSH levels decreased after 14 and 21 days of exposure to 100 and 200 μg/L; nevertheless, GSH recovered basal levels at the end of the experiment. Conclusion: All the three biochemical parameters assessed -mainly inhibition of AChE activity- could be adequate biomarkers of early exposition (less than 14 days) to low doses of carbofuran in biomonitoring programs, being MDA reduction also related to longer exposure.

Resumen Antecedentes: El ambiente acuático está continuamente contaminado con sustancias químicas tóxicas provenientes de actividades industriales, agrícolas y domésticas. La identificación de diferentes biomarcadores de dicha contaminación es de gran relevancia para determinar el impacto potencial de esos xenobióticos en la salud de los organismos. Objetivo: Estimar la idoneidad de diferentes biomarcadores cerebrales bioquímicos de tenca para evaluar el efecto ambiental de una exposición a diferentes concentraciones del pesticida carbofurano. Método: El presente estudio se centró en los efectos de una exposición a largo plazo (28 días) a diferentes concentraciones (50, 100 y 200 μg/L) del pesticida carbofurano sobre determinados parámetros bioquímicos de la tenca (Tinca tinca L.). Los biomarcadores seleccionados para el control del estrés fueron el malondialdehído (MDA), como indicador de peroxidación lipídica, y el glutatión reducido (GSH). Además, se cuantificó la actividad acetilcolinesterasa (AChE), como biomarcador de efecto sobre el sistema nervioso del pez. Resultados: La actividad AChE se inhibió significativamente en los peces expuestos a todas las concentraciones de carbofurano después de 14 y 21 días de exposición, regresando a los niveles basales tras este periodo en las exposiciones con 50 y 100 μg/L. Así mismo se detectaron descensos significativos de los niveles de MDA tras 14 y 21 días de exposición con 200 μg/L, manteniéndose hasta el final del experimento. Los niveles de GSH descendieron tras 14 y 21 días de exposición con 100 y 200 µg/l; sin embargo, los niveles basales se recuperaron al final del experimento. Conclusión: Los tres parámetros bioquímicos evaluados, pero principalmente la inhibición de la actividad de AChE, podrían usarse como biomarcadores de exposición temprana (menos de 14 días) a bajas dosis de carbofurano en programas de biomonitorización, estando la reducción de MDA también relacionada con exposiciones más prolongadas.

Resumo Antecedentes: O meio aquático está sendo continuamente contaminado com substâncias químicas tóxicas de atividades industriais, agrícolas e domésticas. A identificação de diferentes biomarcadores de tal contaminação é de grande relevância para determinar o impacto potencial desses xenobióticos na saúde dos organismos. Objetivo: Estimativa da idoneidade de várias biomarcadores cerebrais bioquímicos de tenca para avaliar o efeito ambiental de uma exposição a diferentes concentrações do pesticida carbofurano. Método: O presente estudo centrou-se no efeito de uma exposição a longo prazo (28 dias) a diferentes concentrações (50, 100 e 200 μg/L) do pesticida carbofurano em certos parâmetros bioquímicos da tenca (Tinca tinca L.). Os biomarcadores selecionados para o monitoramento do estresse foram malondialdeído (MDA), como índice de peroxidação lipídica e glutationa reduzida (GSH). Além disso, a atividade da acetilcolinesterase (AChE) foi quantificada, como biomarcador de efeito sobre o sistema nervoso do peixe. Resultados: A atividade de AChE foi significativamente inibida em peixes expostos a todas as concentrações de carbofurano após 14 e 21 dias de exposição, voltando aos níveis basais após esse período com 50 e 100 μg/L. Além disso, as diminuições significativas dos níveis de MDA podem ser detectadas após 14 e 21 dias de exposição a 200 μg/L, até o final do experimento. Os níveis de GSH diminuíram após 14 e 21 dias de exposição a 100 e 200 μg/L, porém GSH recuperou os níveis basais no final do experimento. Conclusão: Todos os três parâmetros bioquímicos avaliados, mas principalmente a inibição da atividade AChE, podem ser biomarcadores adequados de exposição precoce (menos de 14 dias) a baixas doses de carbofurano em programas de biomonitorização, sendo a redução de MDA também relacionada a exposições mais longas.

The organophosphorus pesticide dimethoate decreases cell viability and induces changes in different biochemical parameters of rat pancreatic stellate cells.

In the present study we employed cultured pancreatic stellate cells to study the effect of the organophosphorus insecticide dimethoate on pancreatic cell physiology. Esterase activity, cell viability, reactive oxygen species generation and Ca2+ mobilization were examined. Our results show that dimethoate (0.1, 1 and 10 µM) induced a concentration-dependent inhibition of cholinesterase enzymatic activity at all concentrations tested. A drop in carboxylesterase activity was noted in the presence of 10 µM dimethoate. In the presence of the pesticide a decrease in cell viability was detected. The clearer effect could be observed when the cells had been incubated during 96 h in the presence of dimethoate. The pesticide induced a slight but statistically significant increase in the production of reactive oxygen species in the mitochondria. Incubation of cells with dimethoate, in the presence of Ca2+ in the extracellular medium, led to a slow and progressive increase in [Ca2+]c towards an elevated value over the prestimulation level. A similar behavior was observed in the absence of extracellular Ca2+, indicating that dimethoate releases Ca2+ from the intracellular stores. Our results suggest that dimethoate might alter intracellular pathways that are critical for pancreatic physiology, creating a situation potentially leading to dysfunction in the exocrine pancreas.

Concentration of 12 Metals and Metalloids in the Blood of White Stork (Ciconia ciconia): Basal Values and Influence of Age and Gender.

The white stork (Ciconia ciconia) is being increasingly used in biomonitoring programmes of environmental contaminants due to its growing population in Europe; however, studies on inorganic elements are scarce. The blood of 70 white storks was collected and analysed by inductively coupled plasma mass spectroscopy (ICP-MS) to determine the presence of the following elements: lead (Pb), mercury (Hg), arsenic (As), nickel (Ni), iron (Fe), zinc (Zn), copper (Cu), selenium (Se), manganese (Mn), chromium (Cr), cobalt (Co), and cadmium (Cd). Our main goals were to determine the mean concentrations of these elements in the blood and to study its association with age and gender. Mean concentrations were highest for Fe, followed by Zn, and lowest for Co and Cd. The metal levels were similar to the values referred in the literature for the same species from different locations. No statistically significant differences were found between males and females. Regarding age, statistically significant differences were observed for Ni, Cu, Se, Hg, and Pb between young and adult animals (except for Pb, values in adults were higher than in fledglings). Many element concentrations were correlated, with the strongest correlations between the pairs Hg-Se, Hg-As, and Fe-Zn, mainly in adults. This study provides the baseline data for a monitoring program based on white stork blood as a nondestructive sample.

Noninvasive heavy metal pollution assessment by means of Iberian wolf (Canis lupus signatus) hair from Galicia (NW Spain): a comparison with invasive samples.

The current study represents the first investigation of the suitability of wolf hair as indicator tissue for metal exposure and accumulation within NW Spanish ecosystems. Dead animals, which were not specifically killed for these purposes, were necropsied, and further toxicological analyses were performed in order to establish the heavy metal content (Pb, Cd, and Zn) in liver, kidney, and hair, by means of inductively coupled plasma optical emission spectrometry. Two different factors, gender and age, were considered in order to determine their influence on heavy metal accumulation. Mean liver, kidney and hair concentrations of both toxic element, Cd (0.528, 2.692, and 0.026 ppm) and Pb (4.108, 0.031, and 0.196 ppm) considered on a dry weight basis, were situated below the established as acute toxicity levels for mammals. The highest concentrations were quantified for Zn, with means ranging from a maximum in hair samples (150.9 ppm) to a minimum in kidney samples (25.81 ppm). When the variable of gender and age were considered, female and adult wolves had higher concentrations of Cd in all the considered organs, although differences were only statistically significant for kidney. Neither the sex nor the age had a significant effect on Pb and Zn concentrations. A significant positive correlation (p < 0.05) was identified between hair and liver Pb concentrations, as well as between hair and kidney Cd concentrations, thus suggesting the interest of the noninvasive sample for future ecotoxicological biomonitoring studies.

Sex- and age-dependent accumulation of heavy metals (Cd, Pb and Zn) in liver, kidney and muscle of roe deer (Capreolus capreolus) from NW Spain.

In the present study, bioaccumulation of lead, cadmium and zinc in liver, kidney and muscle of roe deer (Capreolus capreolus) from Galicia (NW Spain) was quantified. Metal analysis was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In general the quantified concentrations were associated with background environmental levels, except for Pb, where some markedly elevated concentrations were obtained, but with no toxicological relevance. The effect of sex on Cd, Pb and Zn levels was considered, females showing a general trend to accumulate higher concentrations of these metals, with the exception of the hepatic content of Cd (which was significantly higher in males, P < 0.05) and Pb levels, which did not differ according to sex. The effect of age was analysed only in male animals and was clearly observed for Pb levels, with concentrations significantly higher in adult animals (liver: P < 0.01, kidney: P < 0.05 and muscle: P < 0.001) and for Cd levels in kidney samples (P < 0.001). This study provides the first data on heavy metal content in roe deer from the area of study and suggests that this species could be a good bioindicator of metal pollution, even though both factors, sex and age, could represent an important source of variation in the bioaccumulation of these metals in wild populations.

Hepatic monooxygenase (CYP1A and CYP3A) and UDPGT enzymatic activities as biomarkers for long-term carbofuran exposure in tench (Tinca tinca L).

The effect of a long-term exposure of tenchs to different concentrations (10 and 100 micro g/L) of the pesticide carbofuran has been evaluated. Microsomal hepatic cytochrome P450 subfamily 1A (CYP1A) and 3A (CYP3A) activities, as well as the phase II enzyme uridine diphospho-glucuronosyltransferase (UDPGT) activity were evaluated as adequate biomarkers of fish exposure to environmentally relevant concentrations of the pesticide carbofuran in freshwater ecosystems. A clear time-dependent inhibition of both CYP1A and UDPGT activities was observed in fish exposed to the highest dose of carbofuran with respect to controls, whereas in the case of CYP3A activity, values of exposed animals did not show a clear pattern of alteration during the experiment. The results of the present study demonstrated that hepatic CYP1A and UDPGT activities from tench could be considered as sensitive biomarkers for carbamate pesticides in polluted water, thus allowing future and ecologically relevant biomonitoring studies with this species.

Relationship of the toxicity of pesticide formulations and their commercial restrictions with the frequency of animal poisonings.

Deliberate poisoning of domestic animals and wildlife with commercial formulations of pesticides has been documented worldwide. We have compiled the analytical results obtained by four Spanish Laboratories of Veterinary Toxicology since 1990. The frequency of poisonings and the intentional use of pesticides were compared between formulations with restricted and unrestricted use, including the toxicity of the commercial formulations as a covariant in the model. The frequency of poisoning was inversely related with the lethal dose of specific formulations, but not with the amounts consumed in agriculture in Spain. The intentional illegal use of some pesticides as poisons was not affected by the commercial restriction of their formulations, but was inversely correlated with their LD(50). The examination of the data permits us to detect three highly toxic compounds (aldicarb, carbofuran, and strychnine), more widely implicated in animal poisonings than other compounds of similar toxicity.

Heavy metal (Cd, Pb, Zn) and metalloid (As) content in raptor species from Galicia (NW Spain).

As top consumers in food chains, birds of prey forage over large geographical areas and so might be expected to accumulate environmental contaminants which are distributed in the environment. These wild animals can offer opportunities to detect and assess the toxicological effects of different inorganic elements on terrestrial ecosystems. In this study, different raptor species, both diurnal and nocturnal, were investigated for heavy metal (Pb, Cd and Zn) and As concentrations in liver samples, with the aim of furnishing indirect information concerning contamination of their habitats. Dead animals were obtained with the special collaboration of the Wildlife Rehabilitation Centres from Galicia (NW Spain). After sample wet digestion, metal analysis was performed by inductively coupled plasma-mass spectrometry (ICP-MS). Hepatic concentrations of Zn and As, respectively, situated on the interval 147-298 and 1.21-6.88 ppm (dry weight, dw), could be considered as indicative of low and background amounts of both elements, with no ecotoxicological concern. Nevertheless, with respect to Pb, some diurnal raptors showed hepatic concentrations above the considered threshold value (6 ppm dw) for sublethal or lethal toxicity, the species with the highest hepatic level corresponding to a common buzzard (>18 ppm, dw). Similarly, nocturnal raptors exceeded the threshold value for Cd (3 ppm dw), with a maximum corresponding to an individual barn owl (39 ppm, dw). In both cases, although concentrations could not be directly related to lethal effect, they might constitute a serious environmental factor affecting the survival of the considered populations.