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Abstract

Neonicotinoids have recently been demonstrated to cause direct negative impacts on birds from North America and Europe. To further understand the impact of these compounds on bird species and to improve risk assessment capacities, the current study determined the acute toxicities of imidacloprid, clothianidin, and thiamethoxam formulations on South American eared doves (Zenaida auriculata). Insecticides were administered by gavage to adult doves to determine median lethal doses (LD50) according to a standardized sequential procedure. The acute toxicity of formulated imidacloprid (LD50 = 59 mg active ingredient, a.i./kg body weight, b.w.) was much higher than that of the tested formulations of clothianidin (LD50 = 4248 mg a.i./kg b.w.) and thiamethoxam (LD50 = 4366 mg a.i./kg b.w.). Imidacloprid also differed from the other two neonicotinoids in terms of the onset and intensity of intoxication signs and the times of death and recovery. All three insecticides induced a reduction in food consumption that led to body weight loss. An average weight dove of 127 g would obtain a dose equivalent to the LD50 of imidacloprid by consuming 1.7 g of treated sorghum seeds. As eared doves offered non-treated sorghum seeds 5 h per day consumed on average 6.4 ± 1.8 g (mean ± S.D.), it is concluded that these doves could feasibly be exposed to lethal doses in the field. This work is the first to describe intoxication signs and report oral neonicotinoid LD50s in a wild South-American bird species.

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... The signs of intoxication and the strong avoidance with null consumption after the first day of exposure to treated sorghum may indicate the development of a conditioned aversion (or secondary repellency) against the treated sorghum seeds rather than a primary repellency (Sayre and Clark, 2001). However, the primary repellency must not be totally discarded because the different neonicotinoids produced a similar seed avoidance, while their toxicity (and therefore their expected capacity to induce aversion) is quite different among them (Addy-Orduna et al., 2019). The conditioned aversion is a neurobehavioural process induced by the illness or distress caused by the aversive substance (Tobajas et al., 2019a). ...
... The non-detection of neurobehavioral alterations was possibly due to the lower concentration of neonicotinoid and the corresponding exposure dose. The consumed mass of treated soybean seeds in the experiment was less than 0.6% (0.10 g, Table S4) of the amount of seeds to reach LD50 (17.8 g; Addy-Orduna et al., 2019). Regarding cotyledons, the application rates of neonicotinoids used in the field would not be enough to cause signs of intoxication. ...
... In summary, the loss of BW was clearly seen during exposure to the treatments in the sorghum experiment, not in the soybean or cotyledon experiment. In another neonicotinoid study in which eared doves were administered imidacloprid, clothianidin or thiamethoxam via gavage, they also reduced their body weight, mainly during the first days after exposure (Addy-Orduna et al., 2019). The results of other studies regarding the effect of imidacloprid (the most tested neonicotinoid) on the body weight of other bird species is variable. ...
Article
Farmland birds can be exposed to neonicotinoids through the ingestion of treated unburied seeds and cotyledons. The aim of this study was to evaluate the avoidance of sorghum with imidacloprid, clothianidin or thiamethoxam, soybean with imidacloprid, and soybean cotyledons with imidacloprid or thiamethoxam on eared doves (Zenaida auriculata). Doves were fed with test food (untreated and neonicotinoid-treated sorghum, soybean or soybean cotyledons) and maintenance food (seed mix) for 3–5 days to study the repellency (primary repellency and conditioned aversion) and anorexia caused by neonicotinoid-treated food, followed by a 7-day period on maintenance food to study the persistence of the anorexic effect after neonicotinoid exposure. Immediately afterward, the same doves were exposed to treated test food during a second period of 3–5 days to study the potential reinforcement of food avoidance. Finally, doves were fed with untreated test food to test the capacity of the pesticide to induce conditioned food aversion against untreated food in subsequent encounters. Intoxication signs and differences of body weight were determined. With sorghum, the three neonicotinoids produced a decrease in the consumption of treated seeds by >97% compared to control birds. However, this was not enough to prevent the death of 3/8 and 1/8 of the doves exposed to imidacloprid and clothianidin, respectively. Anorexia was clearly observed with neonicotinoid-treated sorghum. The birds did not avoid the untreated sorghum after exposure to the treated sorghum, indicating that avoidance is not generalized to the type of food without an associated sensory cue. The results obtained with soybean seeds and cotyledons were less conclusive because captive doves hardly consumed these foods, even without neonicotinoid treatment. The avoidance of sorghum seeds treated with neonicotinoids was insufficient to prevent poisoning and death of eared doves.
... The signs of intoxication and the strong avoidance with null consumption after the first day of exposure to treated sorghum may indicate the development of a conditioned aversion (or secondary repellency) against the treated sorghum seeds rather than a primary repellency (Sayre and Clark, 2001). However, the primary repellency must not be totally discarded because the different neonicotinoids produced a similar seed avoidance, while their toxicity (and therefore their expected capacity to induce aversion) is quite different among them (Addy-Orduna et al., 2019). The conditioned aversion is a neurobehavioural process induced by the illness or distress caused by the aversive substance (Tobajas et al., 2019a). ...
... The non-detection of neurobehavioral alterations was possibly due to the lower concentration of neonicotinoid and the corresponding exposure dose. The consumed mass of treated soybean seeds in the experiment was less than 0.6% (0.10 g, Table S4) of the amount of seeds to reach LD50 (17.8 g; Addy-Orduna et al., 2019). Regarding cotyledons, the application rates of neonicotinoids used in the field would not be enough to cause signs of intoxication. ...
... In summary, the loss of BW was clearly seen during exposure to the treatments in the sorghum experiment, not in the soybean or cotyledon experiment. In another neonicotinoid study in which eared doves were administered imidacloprid, clothianidin or thiamethoxam via gavage, they also reduced their body weight, mainly during the first days after exposure (Addy-Orduna et al., 2019). The results of other studies regarding the effect of imidacloprid (the most tested neonicotinoid) on the body weight of other bird species is variable. ...
... In Argentina, the use of IMI is approved for all major crops cultivated in the Pampa Region and IMI is widely used for seed treatment (SENASA, 2020). However, a single study previously examined the toxicity of IMI to a native bird species, the eared dove (Zenaida auriculata), and demonstrated that the consumption of only a few grains of sorghum treated with IMI is sufficient to cause death (Addy-Orduna et al., 2019). In this context, and because no toxicity data is available for any South American passerine species, the aim of the present study was to estimate the risk posed by IMI seed coating to native passerine birds of the Pampa Region of Argentina. ...
... In Stage 1, four birds were given four doses (i.e., 8.48, 31.3, 115, 424 mg IMI/kg bw), the doses having been estimated on a logarithmic scale around the reference dose of 60 mg IMI/kg bw obtained by Addy-Orduna et al. (2019) for Zenaida auriculata. The mortalities observed in Stage 1 provided a working estimate of the LD 50 that was used to establish the 10 doses used in Stage 2 (i.e., 20.6, 26.1, 33.1, 42, 53.3, 67.6, 85.7, 109, 138, 175 mg IMI/kg bw), with one individual tested per dose. ...
... IMI binding to the nicotinic receptors in the nervous system causes neuron hyper-excitation that results in uncoordinated movements, loss of balance, reduced locomotion, tremors, paralysis, seizures, and death (Yamamoto and Casida, 1999;Tomizawa and Casida, 2005). The severity of the signs observed was dose-dependent, similar to previous reports from other species (Avery et al., 1993;Emam et al., 2018;Rawi et al., 2019;Abu Zeid et al., 2019;Addy-Orduna et al., 2019;Franzen-Klein et al., 2020). The lowest dose at which mortality occurred was 37.7 mg IMI/kg bw, but the first intoxication signs were present starting at 20.6 mg IMI/kg bw, which corresponds to 36% of the LD 50 . ...
Article
The aim of this study was to estimate the risk posed by imidacloprid (IMI) seed coating to passerine birds of the Pampa Region of Argentina using data specifically generated with the grayish baywing (Agelaioides badius). Median lethal dose (LD50) of the IMI-based formulation tested was 57.11 mg IMI/kg body weight (bw), with intoxication signs starting from 20.6 mg IMI/kg bw. The feed intake rate (FIR) was estimated experimentally as 4.895 g/day per bird, representing 12.43% of bw. It was calculated that the ingestion of 7–10% of the FIR as treated seeds would be enough to achieve the LD50 for sorghum, corn, sunflower, and alfalfa,whereas consumption of 31 and 54% of FIRwas necessary for oat andwheat, respectively. Based on spill data values available in the literature, it was calculated that, for most crops, a baywing would have to forage an area of field corresponding to less than 60 m2 to obtain the number of seeds required to reach the LD50. It was also shown that this number of seeds is coherent with the amount of seeds ingested in a bout. In a pilot study, all grayish baywings fed with millet seeds treated with 3 g IMI/kg died within three to five days of exposure. In Tier I risk assessment, the trigger value was achieved for all crops except soybean and a weight-of-evidence risk assessment was performed. All lines of evidence examined are consistent with the view that grayish baywings, and probably other small farmland birds, are exposed to a risk of acute toxicity and mortality under bothworst-case and mixed-ration exposure scenarios. The possible impacts on bird species calls for an urgent reconsideration of IMI seed coating practices currently approved in the Pampa Region of Argentina and the various parts of the world where this practice is still in use.
... Bars: Pesticide Usage Survey data for annual weight (kg) of NN applied, moderated by a toxicity equivalency factor (TEF) to account for differences in the acute (Fig 1A) or chronic (Fig 1B) toxicity of each NN compound to birds (see Methods for details) [9]. Lines: breeding bird index for farmland birds based on 19 indicator species (those deemed dependent on farmland habitat), 12 experienced population declines of between 23 and 97% [13]. The steepest declines took place between the mid-1970s and the early-1990s (Fig 1) when the amount of farmland hedgerow had decreased significantly, a widespread switch to autumn sowing occurred, and the number of commercial pesticides in use (including DDT up until it was banned in 1986) rose from 137 to 344 as a result of agricultural intensification [14]. ...
... NNs were first used as agricultural plant protection products in Britain in 1994 [15] at a time when farmland bird declines appeared to slow. Nevertheless, there are growing concerns within the scientific community regarding the availability of NNs to birds and the potential for effects of NNs on avian physiology and behaviour [11,[16][17][18][19][20][21]. ...
... Finally, the analysis did not consider any particularly sensitive timings for NN application. As such, sub-lethal effects during the reproductive period were not specifically targeted, but were rather considered alongside the multiple sub-lethal endpoints proposed to result from neonicotinoid exposure in wild birds [19,21,31,53] and which may affect both survival and productivity. ...
Article
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Over the last 20 years, a new group of systemic insecticides – the neonicotinoids - has gained prominence in arable systems, and their application globally has risen year on year. Previous modelling studies using long-term data have suggested that neonicotinoid application has had a detrimental impact on bird populations, but these studies were either limited to a single species or neglected to analyse specific exposure pathways in conjunction with observed population trends. Using bird abundance data, neonicotinoid usage records and cropping data for England at a 5x5 km resolution, generalised linear mixed models were used to test for spatio-temporal associations between neonicotinoid use and changes in the populations of 22 farmland bird species between 1994 and 2014, and to determine whether any associations were explained by dietary preferences. We assigned farmland bird species to three categories of dietary exposure to neonicotinoids based on literature data for species diets and neonicotinoid residues present in dietary items. Significant estimates of neonicotinoid-related population change were obtained for 13 of the 22 species (9 positive effects, 4 negative effects). Model estimates for individual species were not collectively explained by dietary risk categories, so dietary exposure to neonicotinoids via ingestion of treated seeds and seedlings could not be confirmed as a causal factor in farmland bird declines. Although it is not possible to infer any generic effect of dietary exposure to neonicotinoids on farmland bird populations, our analysis identifies three species with significant negative estimates that may warrant further research (house sparrow Passer domesticus, skylark Alauda arvensis and red-legged partridge Alectoris rufa). We conclude that there was either no consistent effect of dietary exposure to neonicotinoids on farmland bird populations in England, or that any over-arching effect was not detectable using our study design. The potential for indirect effects of insecticide use on bird populations via reduced food availability was not considered here and should be a focus for future research.
... However, poisoning incidents are likely grossly underestimated because scavenging of carcasses (Ponce et al., 2010) or depredation by predators can make them hard to detect, especially when few animals are involved (Millot et al., 2017). Furthermore, carcasses may not be localized if exposure effects are delayed (de Snoo et al., 1999;Addy-Orduna et al., 2019;Franzen-Klein et al., 2020) and animals move away from the site of exposure, potentially obscuring the source of mortality. Carcasses can also be inconspicuous (de Snoo et al., 1999) in dense vegetation or other concealed places where sick animals may retreat after exposure. ...
... Immune suppression has been reported from thiamethoxam exposure in chicks (Gul et al., 2018) and from imidacloprid exposure in both adults and chicks (Lopez-Antia et al., 2013;Lopez-Antia et al., 2015, respectively). Additionally, imidacloprid can produce hyporeactivity, wing drop, immobility, and lack of coordination or inability to fly (Cox, 2001;Goulson, 2013;Addy-Orduna et al., 2019;Franzen-Klein et al., 2020), as well as effects on migratory orientation and delays in migration in field experiments (Eng et al., 2017(Eng et al., , 2019. This is not a comprehensive list, but rather a sample of studies that report effects that could reduce survival and reproduction in wild birds. ...
Article
The most likely route of exposure to high concentrations of neonicotinoids capable of producing lethal or sublethal effects in birds and mammals is consumption of treated seeds. We placed trail cameras at simulated seed spills to document wildlife consuming treated seeds during the spring planting season. We simulated 4 types of spills, corn treated with 2 concentrations of clothiandin (0.5 or 0.25 mg/seed), corn treated with thiamethoxam (0.25 mg/seed), and soybean treated with imidacloprid (0.15 mg/seed). We documented 16 species of birds and 14 species of mammals eating neonicotinoid-treated seeds at spills. Of these, we quantified consumption of treated seeds by 12 species of birds and 13 species of mammals. Birds and mammals did not consume enough seeds to exceed published LD50s in related taxa, but most species did consume enough seeds to reach or exceed thresholds for sublethal effects based on currently available studies. Birds and mammals did not increase the amount of seeds consumed over time, as would be expected if responsive to the concentration of neonicotinoids on seeds, but more birds and mammals consumed seeds over time, as a proportion of the number at spills each day. More birds also consumed seeds after a soaking rain event, which likely reduced the amount of treatment on the seeds. Importantly, wildlife are consuming seeds while neonicotinoids are still concentrated on seeds. Our findings indicate that previously held assumptions about the safety of neonicotinoid seed treatments for vertebrate wildlife need to be revisited.
... Relative toxicity to birds differs markedly between NN compounds (Tomizawa and Casida, 2005); for example the acute dose that is lethal to 50% of the test population (LD 50 ) for bobwhite quail Colinus virginianusis is 152 mg/kg/body weight for imidacloprid, but N2000 mg/kg/body weight for clothianidin (European Food Safety Authority, 2006). In aviary conditions, NNs are known to cause sublethal effects in birds, such as adverse impacts on the reproductive system (Lopez-Antia et al., 2013;Pandey and Mohanty, 2015;Mohanty et al., 2017;Pandey and Mohanty, 2017), alterations to the immune system (Lopez-Antia et al., 2013), neurotoxic symptoms (Addy-Orduna et al., 2018;Rawi et al., 2019), oxidative stress (Zeid et al., 2019) and changes to behaviour (Eng et al., 2017;Cox, 2001); many of these sub-lethal effects have been reported at environmentally-relevant doses in laboratory studies using wild bird species. Furthermore, Mineau and Palmer (2013) estimated that the ingestion of 1.3 imidacloprid-or 4.4 clothianidin-coated wheat seeds would be sufficient to breach adverse reproductive end points in a small (15 g) songbird, based on a typical seed loading of 0.033 and 0.025 mg/g of imidacloprid and clothianidin, respectively (Mineau and Palmer, 2013). ...
... These estimations are constructed based on single visits, so could be under-estimating exposure when considering availability of treated seed in the broader landscape. Notably, the two individuals (one tree sparrow and one yellowhammer) that had the highest CLO plasma concentrations for their species (4880 and 69,300 ng/mL, respectively) exhibited intoxication symptoms at time of capture, which were similar to those described in imidacloprid-dosed eared doves (Addy-Orduna et al., 2018). These individuals also had red dye around the bill and red faeces, indicating recent ingestion of CLO-coated seeds, as has similarly been reported in NN poisoning incidents (Millot et al., 2017). ...
Article
Full-text available
Neonicotinoids are the largest group of systemic insecticides worldwide and are most commonly applied as agricultural seed treatments. However, little is known about the extent to which farmland birds are exposed to these compounds during standard agricultural practices. This study uses winter cereal, treated with the neonicotinoid clothianidin, as a test system to examine patterns of exposure in farmland birds during a typical sowing period. The availability of neonicotinoid-treated seed was recorded post-sowing at 39 fields (25 farms), and camera traps were used to monitor seed consumption by wild birds in situ. The concentration of clothianidin in treated seeds and crop seedlings was measured via liquid chromatography-tandem mass spectrometry, and avian blood samples were collected from 11 species of farmland bird from a further six capture sites to quantify the prevalence and level of clothianidin exposure associated with seed treatments. Neonicotinoid-treated seeds were found on the soil surface at all but one of the fields surveyed at an average density of 2.8 seeds/m². The concentration of clothianidin in seeds varied around the target application rate, whilst crop seedlings contained on average 5.9% of the clothianidin measured in seeds. Exposure was confirmed in 32% of bird species observed in treated fields and 50% of individual birds post-sowing; the median concentration recorded in positive samples was 12 ng/mL. Results here provide clear evidence that a variety of farmland birds are subject to neonicotinoid exposure following normal agricultural sowing of neonicotinoid-treated cereal seed. Furthermore, the widespread availability of seeds at the soil surface was identified as a primary source of exposure. Overall, these data are likely to have global implications for bird species and current agricultural policies where neonicotinoids are in use, and may be pertinent to any future risk assessments for systemic insecticide seed treatments.
... Lethal effects are characterised by the death of the individual soon after exposure and reflect acute toxicity. The ingestion of seeds coated with neonics or exposure to other insecticides that impair nervous function, such as CBs and OPs (AChE inhibitors, Casida & Durkin, 2013;Maroni et al., 2000), can have lethal effects on birds (Elliott et al., 1996, Addy-Orduna et al., 2019Poliserpi et al., 2021). This has been reported, for example, among granivorous grey partridges (P. ...
Article
Full-text available
For decades, we have observed a major biodiversity crisis impacting all taxa. Avian spe- cies have been particularly well monitored over the long term, documenting their declines. In particular, farmland birds are decreasing worldwide, but the contribution of pesticides to their decline remains controversial. Most studies addressing the effects of agrochemicals are limited to their assessment under controlled laboratory conditions, the determination of lethal dose 50 (LD50) values and testing in a few species, most belonging to Galliformes. They often ignore the high interspecies variability in sensitivity, delayed sublethal effects on the physiology, behaviour and life-history traits of individuals and their con- sequences at the population and community levels. Most importantly, they have entirely neglected to test for the multiple exposure pathways to which individu- als are subjected in the field (cocktail effects). The present review aims to provide a comprehensive over- view for ecologists, evolutionary ecologists and con- servationists. We aimed to compile the literature on the effects of pesticides on bird physiology, behaviour and life-history traits, collecting evidence from model and wild species and from field and lab experiments to highlight the gaps that remain to be filled. We show how subtle nonlethal exposure might be pernicious, with major consequences for bird populations and communities. We finally propose several prospec- tive guidelines for future studies that may be consid- ered to meet urgent needs.
... NEOs have the potential to cause a sudden decline in the adult honeybee population, also known as colony collapse disorder (Henry et al. 2012). Many studies have reported on the acute toxicity of NEOs to aquatic invertebrates, birds, and mammals from in vitro and in vivo laboratory toxicity experiments Han et al. 2018;Addy-Orduna et al. 2019). The potential toxic effects of NEOs mainly include reproductive toxicology, neurotoxicity, hepatotoxicity, immunotoxicity, and genetic toxicity (Han et al. 2018). ...
Article
Full-text available
Neonicotinoids (NEOs) are a class of insecticides that have high insecticidal activity and are extensively used worldwide. However, increasing evidence suggests their long-term residues in the environment and toxic effects on nontarget organisms. NEO residues are frequently detected in water and consequently have created increasing levels of pollution and pose significant risks to humans. Many studies have focused on NEO concentrations in water; however, few studies have focused on global systematic reviews or meta-analyses of NEO concentrations in water. The purpose of this review is to conduct a meta-analysis on the concentration of NEOs in global waters based on published detections from several countries to extend knowledge on the application of NEOs. In the present study, 43 published papers from 10 countries were indexed for a meta-analysis of the global NEO distribution in water. Most of these studies focus on the intensive agricultural area, such as eastern Asia and North America. The order of mean concentrations is identified as imidacloprid (119.542 ± 15.656 ng L⁻¹) > nitenpyram (88.076 ± 27.144 ng L⁻¹) > thiamethoxam (59.752 ± 9.068 ng L⁻¹) > dinotefuran (31.086 ± 9.275 ng L⁻¹) > imidaclothiz (24.542 ± 2.906 ng L⁻¹) > acetamiprid (23.360 ± 4.015 ng L⁻¹) > thiacloprid (11.493 ± 5.095 ng L⁻¹). Moreover, the relationships between NEO concentrations and some environmental factors are analyzed. NEO concentrations increase with temperature, oxidation–reduction potential, and the percentage of cultivated crops but decrease with stream discharge, pH, dissolved oxygen, and precipitation. NEO concentrations show no significant relations to turbidity and conductivity.
... 1,2 At present, the most effective method to control aphids is chemical insecticides, 3 but these brought many insecticide resistance problems in the past decades and issues to harm nontarget organisms, especially bees. [4][5][6][7][8] Recently, it has been discovered that the application of some neonicotinoid insecticides led to a population decrease of bees. To protect the ecological environment, several neonicotinoid insecticides that are toxic to bees are prohibited from being used on all outdoor crops, 9,10 therefore the development of novel eco-friendly aphid control agents with no bee toxicity is urgent to support further sustainable agriculture. ...
Article
Full-text available
Background: As one of the most abundant and destructive pests in agriculture, aphids cause significant damage to crops due to their sap taking and as virus vectors. Chemical insecticides are the most effective method to control aphids, but they bring insecticide resistance problems and harm non-target organisms, especially bees. Therefore, the search for novel eco-friendly aphid control agents with low bee toxicity is urgent. Insect kinins are a class of small neuropeptides that control important functions in insects. In our previous study, we found insect kinin analog IV-3 has good aphicidal activity and the location of the aromatic ring on the side chain of Phe2 is the key to the formation of the β-turn resulting in the biological activity of insect kinin analogs. However, there are few studies on insect kinins Phe2 substitution and modification, and its structure-activity relationship is still unclear. Results: In this project, 44 insect kinin analogs with the Phe2 modification, by replacing it with different natural or unnatural amino acids, were designed and synthesized based on the lead IV-3 to explore the role of the Phe2 residues. The bioassays with soybean aphids of Aphis glycines indicated that 9 analogs have better aphicidal activity than the lead IV-3. In particular, compound L25 exhibits excellent aphicidal activity (LC50 =0.0047 mmol/L) and has low toxicity to bees. Furthermore, a reliable three-dimensional quantitative structure-activity relationship (3D-QSAR) was established to produce a helpful clue that introducing hydrophobic groups away from the backbone chain is beneficial to improve aphicidal activity. Conclusion: The residue Phe2 of insect kinins analogs is the key position, which has a more significant impact on the activity. L25 has a high toxicity for aphids, while a low toxicity to bees, and therefore can be considered as a lead compound to develop new biosafe aphid control agents. Finally, we provide a useful 3D-QSAR model as a theoretical guidance for further structural optimization. This article is protected by copyright. All rights reserved.
... The neonicotinoid acetamiprid, for example, was shown to induce a cytotoxic effect on mammalian cells (57). Imidacloprid, thiamethoxam, and clothianidin led to reduced food intake and associated weight loss in eared doves and it was shown that the increased use of neonicotinoids in general reduced bird biodiversity (58,59). The neonicotinoids imidacloprid and thiamethoxam can even lead to cyto-and genotoxic effects in plants (60). ...
Article
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Honeybees and wild bees are among the most important pollinators of both wild and cultivated landscapes. In recent years, however, a significant decline in these pollinators has been recorded. This decrease can have many causes including the heavy use of biocidal plant protection products in agriculture. The most frequent residues in bee products originate from fungicides, while neonicotinoids and, to a lesser extent, pyrethroids are among the most popular insecticides detected in bee products. There is abundant evidence of toxic side effects on honeybees and wild bees produced by neonicotinoids, but only few studies have investigated side effects of fungicides, because they are generally regarded as not being harmful for bees. In the field, a variety of substances are taken up by bees including mixtures of insecticides and fungicides, and their combinations can be lethal for these pollinators, depending on the specific group of insecticide or fungicide. This review discusses the different combinations of major insecticide and fungicide classes and their effects on honeybees and wild bees. Fungicides inhibiting the sterol biosynthesis pathway can strongly increase the toxicity of neonicotinoids and pyrethroids. Other fungicides, in contrast, do not appear to enhance toxicity when combined with neonicotinoid or pyrethroid insecticides. But the knowledge on possible interactions of fungicides not inhibiting the sterol biosynthesis pathway and insecticides is poor, particularly in wild bees, emphasizing the need for further studies on possible effects of insecticide-fungicide interactions in bees.
... Trials have been conducted to compare consumption of treated versus untreated seeds in captivity, and when given the choice birds sometimes show a preference for untreated seeds, depending on what the treatment is (Werner et al. 2010;Pascual et al. 1999b;Bennett and Prince 1981;Avery et al. 1993;Lopez-Antia et al. 2014). Consumption of treated seeds may drop over time as toxic effects begin to manifest, as, for example, occurring in eared doves fed imidacloprid-treated seeds (Addy-Orduna et al. 2019, Avery et al. 1994Lopez-Antia et al. 2013;Millot et al. 2017;Botha et al. 2018). Conversely, the repellency of seeds coated with the fungicides thiram and carboxin or pyrethroid insecticides may diminish over time in the absence of alternative food and possibly even form addictive effects (David 1981;Kennedy and Connery 2008;Werner et al. 2010;Lopez-Antia et al. 2014). ...
Article
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We determine the exposure of wild birds to pesticides via consumption of fludioxonil-treated winter wheat seeds following autumn drilling. We recorded the density of seeds left on the soil surface, bird density, and consumption of pesticide-treated seed by birds using camera traps. We calculated the dose ingested by each bird species in a single feeding bout and if they ate treated seeds exclusively for 1 day. We extrapolated this for an additional 19 pesticides commonly used as seed treatments, assuming equal consumption rates. All three fields contained grains on the soil surface (mean 7.14 seeds/m 2 on sowing day). In total, 1,374 granivorous birds spanning 18 different species were observed in the fields, with 11 species filmed eating the seeds. Fludioxonil appears to pose a low risk to birds, with <1.14% of the LD50 potentially ingested by a bird for a daily maximum amount of seeds. Analysis of the further 19 pesticides commonly used as seed dressings suggests that the neonicotinoid insecticides imidacloprid, clothianidin, and thiamethoxam represent the highest risk for granivorous birds. For example, chaffinch (Fringilla coelebs) could consume 63% of LD50 of imidacloprid in a single feeding bout, and 370% in a day. Further investigation is clearly required to determine whether seeds treated with these other pesticides are consumed as readily as those treated with fludioxonil, as if so this is likely to cause significant harm.
... A diversity of non-lethal behavioral and physiological negative impacts have been documented in vertebrates exposed to doses (e.g. 0.02-2000 mg kg −1 ) of neonicotinoids [8][9][10][11][12][13] . In recent studies, birds exposed to imidacloprid, one of the most commonly used neonicotinoids, showed reduced migratory fat stores, delayed migration and potentially altered migratory orientation 8,9 . ...
Article
Full-text available
Neonicotinoids are insecticides widely used as seed treatments that appear to have multiple negative effects on birds at a diversity of biological scales. Adult birds exposed to a low dose of imidacloprid, one of the most commonly used neonicotinoids, presented reduced fat stores, delayed migration and potentially altered orientation. However, little is known on the effect of imidacloprid on birds growth rate despite studies that have documented disruptive effects of low imidacloprid doses on thyroid gland communication. We performed a 2×2 factorial design experiment in Zebra finches, in which nestling birds were exposed to a very low dose (0.205 mg kg body mass-1) of imidacloprid combined with food restriction during posthatch development. During the early developmental period, imidacloprid exposure resulted in an improvement of body condition index in treated nestlings relative to controls. Imidacloprid also led to compensatory growth in food restricted nestlings. This early life neonicotinoid exposure also carried over to adult age, with exposed birds showing higher lean mass and basal metabolic rate than controls at ages of 90–800 days. This study presents the first evidence that very low-dose neonicotinoid exposure during early life can permanently alter adult phenotype in birds.
... Neurobehavioral effects appeared shortly following the rapid absorption of IMI, in some cases immediately after dosing, as previously reported for other species (Addy-Orduna et al., 2019;Avery et al., 1993;Franzen-Klein et al., 2020). Half an hour after dosing, 90% of grayish baywings presented intoxication signs. ...
Article
The neonicotinoids are globally used insecticides, which have been shown to cause negative impacts on birds. The current study aimed to evaluate the distribution of the neonicotinoid imidacloprid (IMI) in the tissues of a songbird and identify related physiological effects. Adults of the grayish baywing (Agelaioides baduis) were administered with a single dose of 35 mg IMI/kg, and the IMI concentration was evaluated in liver, kidney and plasma at 4, 12, 24, and 48 h after dosing. At the same time points, effects on hematological, genetic and enzymatic parameters were assessed. Results showed that IMI was absorbed before 4 h, and eliminated at 48 h, in every tissue, and the highest concentrations were detected in plasma. Baywings showed intoxication signs and reduced mobility within the first five minutes post-dosing. Hematological parameters: red blood cells, hematocrit, hemoglobin, and their derived indices exhibited a transient elevation 24 h after dosing, which coincided with maximum concentrations of IMI in the tissues. No effects were observed on the genotoxicity parameters evaluated: micronuclei and comet assay. Treated birds exhibited an inhibition of cholinesterases activity in the muscle, and of glutathione-S-transferase (GST) activity in the plasma, brain, and muscle. Based on the results obtained, the combined detection of IMI and inhibition of GST activity in the plasma is suggested as a non-lethal biomarker of IMI exposure in wild birds. As efficient field monitoring depends on the availability of proven biomarkers, the current study provides valuable tools for bird conservation in agroecosystems.
... On that account, restriction has been imposed on numerous organochlorines (OCs), including DDT, throughout the world. As a result of persistence and bioaccumulation they are prevalent and are detected in coastal ecosystem [51], wetlands [52], fruits [53], birds [54]. This increasing concentration of pesticides at successively higher levels in the food chain is called biomagnification [29]. ...
... This increase in stopover duration may put these birds at a disadvantage in competing for good breeding or non-breeding sites and may decrease their overall fitness. Pesticides may also affect a bird's ability to fly even after they recommence their migration (Goulson, 2013;Addy-Orduna et al., 2019;Franzen-Klein et al., 2020), further affecting their overall fitness and increasing their risk of mortality. ...
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An estimated 17% of migratory bird species are threatened or near threatened with extinction. This represents an enormous potential loss of biodiversity and cost to human societies due to the economic benefits that birds provide through ecosystem services and ecotourism. Conservation of migratory bird species presents many unique challenges, as these birds rely on multiple geographically distinct habitats, including breeding grounds, non-breeding grounds, and stopover sites during migration. In particular, stopover habitats are seldom studied relative to breeding and non-breeding habitats, despite their importance as refueling stations for migratory birds. In this study, we summarize the current research on the use of temporary primary crops by birds during migration and we assess the species characteristics and agricultural practices most often associated with the use of cropland as stopover habitat. First, we conducted a systematic review of the literature to document the effects various farming practices and crop types have on the abundance and diversity of migratory birds using agricultural areas for stopovers. Second, we analyzed the ecological correlates of bird species in the Northern Hemisphere that predict which species may use these areas while migrating. We ran a GLMM to test whether primary diet, diet breadth, primary habitat, habitat breadth, or realm predicted stopover use of agricultural areas. Our review suggests that particular crop types (principally rice, corn, and sunflower), as well as farming practices that result in higher non-cultivated plant diversity, encourage the use of agricultural areas by migrating birds. We found that cropland is used as stopover habitat by bird species that can utilize a large breadth of habitats, as well as species with preferences for habitat similar in structure to agricultural areas.
... Afterwards, the concentrations of TCP and clothianidin were concentrated 1.12 and 2.47 fold, respectively. Since TCP and clothianidin have higher toxicities than chlorpyrifos and thiamethoxam (Muscarella et al. 1984;Addy-Orduna et al. 2019), respectively, this study shows that the decocting process employed during the preparation of TCMs, such as P. radix, can concentrate pesticide residues or convert residues into their more toxic metabolites. ...
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Numerous natural preparations in traditional Chinese medicine are prepared as decoctions. Processing factors (PFs) comparing the levels of pesticide residues in decoctions to those in the corresponding unprocessed products should be considered in exposure assessments. Thus, this study determined the residue levels of six pesticides (chlorpyrifos, phoxim, imidacloprid, thiamethoxam, fenpropathrin, and emamectin benzoate), as well as 3,5,6-trichloropyridinol, the primary metabolite of chlorpyrifos, and clothianidin, the main metabolite of thiamethoxam in Baishao, Paeoniae radix lactiflora (Fam. Ranunculaceae). The results showed that significant time-response effects were present for the release of pesticides from P. radix. The PFs calculated were < 1, indicating a significant reduction in pesticide residues after TCM processing. The water solubility and partition coefficient values of the pesticides may have played a basic role in the dissipation of the residues during the TCM decocting process. A risk assessment based on the hazard quotient with PFs revealed that exposure to pesticide residues in P. radix was far below the levels that might pose a health risk. In conclusion, the results presented here are of theoretical and practical value for the safety evaluation of TCMs.
... In 2018, the European Commission banned the outdoor use of clothianidin (Commission Implementing Regulation (EU), 2018a), imidacloprid (IMC) (Commission Implementing Regulation (EU), 2018b), and thiamethoxam (Commission Implementing Regulation (EU), 2018c) but no regulation have been established for the others yet. Although many studies have reported neonicotinoid bioaccumulation in birds from Europe (Addy-Orduna et al., 2019;Humann-Guilleminot et al., 2019;Lennon et al., 2019), little is known about the accumulation of these contaminants in raptors. In fact, no studies on analysis of neonicotinoids in these species were found beyond Europe. ...
Article
Raptors (birds of prey and owls) have been widely used as suitable bioindicators of environmental pollution. They occupy the highest trophic positions in their food chains and are documented to bioaccumulate high concentrations of persistent pollutants such as toxic metals and legacy persistent organic pollutants (POPs).Whereas raptors played a critical role in developing awareness of and policy for chemical pollution, they have thus far played a much smaller role in current research on contaminants of emerging concern (CECs). Given the critical knowledge obtained from monitoring 'legacy contaminants' in raptors, more information on the levels and effects of CECs on raptors is urgently needed. This study critically reviews studies on raptors from Europe reporting the occurrence of CECs with focus on the investigated species, the sampled matrices, and the bioanalytical methods applied. Based on this, we aimed to identify future needs for monitoring CECs in Europe. Perfluoroalkyl substances (PFASs), novel flame retardants (NFRs), and to a lesser extent UV-filters, neonicotinoids, chlorinated paraffins, parabens and bisphenols have been reported in European raptors. White-tailed Eagle (Haliaeetus albicilla), Peregrine falcon (Falco peregrinus) and Northern goshawk (Accipiter gentilis) were the most frequently studied raptor species. Among matrices, eggs, feathers and plasma were the most widely employed, although the potential role of the preen gland as an excretory organ for CECs has recently been proposed. This review highlights the following research priorities for pollution research on raptors in Europe: 1) studies covering all the main classes of CECs; 2) research in other European regions (mainly East Europe); 3) identification of the most suitable matrices and species for the analysis of different CECs; and 4) the application of alternative sample treatment strategies (e.g. QuEChERS or pressurized liquid extraction) is still limited and conventional solvent-extraction is the preferred choice.
... To avoid these undesired consequences, a few approaches have been made to reduce their effects. A new generation of pesticides has been formulated to be less toxic and safer (Addy-Orduna et al., 2019). These newly generated pesticides are designed to be quickly degraded in the environment and living organisms. ...
Chapter
Pesticides can contaminate environmental resources. In addition to killing insects or weeds, pesticides can be toxic to a host of other organisms including animals, and non-target plants. In low-income countries, growers and farmers have little or no access to information about the proper use of the pesticides in either the preparation or application stages. In this chapter, we will outline the toxic effects of low doses of pesticides on non-target organisms, as well as the toxicity of the new generation of pesticides, including plant-derived ones on non-target organisms and the environment.
... The recent detections of neonicotinoids in plasma in wild insectivorous songbirds (Hao et al., 2018), diurnal raptors (Byholm et al., 2018), owls (Taliansky-Chamudis et al., 2017), livers of granivorous birds such as wild Turkeys (Meleagris gallopavo) (MacDonald et al., 2018), feathers of house sparrows (Passer domesticus) (Humann-Guilleminot et al., 2019), and in feathers, whole body carcasses and cloacal fluid of hummingbirds (Bishop et al., 2018;Graves et al., 2019) reveal that these compounds are present in terrestrial vertebrates at multiple trophic levels. The pervasive occurrence of these compounds in wildlife tissues raises concerns because environmentally relevant exposure in birds to neonicotinoids insecticides can be lethal and sublethally neurotoxic to birds and are associated with population declines of insectivorous birds (Lopez-Antia et al., 2013;Gibbons et al., 2014;Hallmann et al., 2014;Eng et al., 2017;Botha et al., 2018;Addy-Orduna et al., 2019;Eng et al., 2019;Rogers et al., 2019). Similarly, phenylpyrazole insecticides such as fipronil are systemic and can be neurotoxic with similar toxicity and persistence profiles to the neonicotinoids (Grant et al., 1998;Simon-Delso et al., 2015). ...
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To examine the spatial, and temporal variation and potential sources of pesticide concentrations, primarily neonicotinoid insecticides, in hummingbirds in western Canada, we sampled their cloacal fluid from sites in British Columbia and Saskatchewan, Canada in 2017–2018. At a sub-sample of those sites, we also measured pesticides in honey bee (Apis mellifera) nectar, water, and sediment. We collected cloacal fluid from 5 species of hummingbirds (n = 26 sites) in British Columbia (BC) and Saskatchewan, Canada, and nectar from honey bee hives (n = 4 sites), water and sediment (n = 18 sites) in the Fraser Valley, BC. Among those, multiple types of samples were collected at 6 sites. We report the first measurement of flupyradifurone, a relatively new butenolide insecticide, in wildlife which was detected at 4.58 ng/mL in hummingbird cloacal fluid and 2.18 ng/g in honey bee nectar. We also detected three other neonicotinoids (imidacloprid, clothianidian, acetamiprid) and one metabolite desnitro-imidacloprid, and MGK264, a pesticide synergist, in our samples. Among 49 samples of cloacal fluid from rufous (Selasphorus rufus), Anna's (Calypte anna), calliope (Selasphorus calliope) black-chinned (Archilocus alexandri) and ruby-throated hummingbirds (Archilocus colubris), 26.5% (n = 13) contained neonicotinoids. Maximum pesticide concentrations in hummingbirds, water and sediment were found in samples collected in the Fraser Valley, BC within 0.5 km of conventionally sprayed blueberry fields (CSBF) but highest levels in honey bee nectar were detected at a site 1.5 km from a CSBF. Imidacloprid in honey bee nectar at one site exceeded concentrations (>1 ng/g) that can sublethally affect worker bee foraging efficiency. In water, imidacloprid concentrations at another site exceeded Canadian guidelines (230 ng/mL) for the protection of aquatic invertebrates.
... An obvious possible explanation for this result is that water bodies could be associated to other confounding environmental factors that were not considered in this study. For example, neonicotinoids, which are largely used broad-spectrum insecticides and have been shown to be toxic for many species, including birds, are highly soluble compounds in water and have been found in high concentrations in waters surrounding the Montreal region (Gibbons et al. 2015;Lopez-Antia et al. 2015;Morrissey et al. 2015;Addy-Orduna et al. 2019;Giroux 2019;Montiel-León et al. 2019). Their solubility combined to many other chemical properties can lead to great concentrations of those pesticides in water bodies near cultivated areas which, in turn, can lead to the contamination of the aquatic invertebrates in those areas . ...
Article
Natural selection has been studied for several decades, resulting in the computation of thousands of selection estimates. Although the importance of environmental conditions on selection has often been suggested, published estimates rarely take into account the effects of environmental heterogeneity on selection patterns. Here, we estimated linear and non‐linear viability selection gradients on morphological traits of 12 days‐old nestlings in a wild population of tree swallows (Tachycineta bicolor) across a large‐scale heterogeneous study system in southern Québec, Canada. We assessed the environmental drivers of nestling survival and evaluated their effects on strength and direction of selection gradients. Separate analyses of environmental variables showed that high temperatures and heavy rainfall caused stronger positive linear selection on morphological traits. Weaker linear selection was also measured in more extensively cultivated areas. Both strength and shape of non‐linear quadratic and correlational components of selection were modified by environmental variables. Considering all environmental variables revealed that precipitation since hatching affected patterns of linear selection on traits, while temperature since hatching shaped nonlinear selection patterns. Our study underlines the importance of quantifying linear and non‐linear natural selection under various environmental conditions and how the evolutionary response of traits may be affected by ongoing human‐induced environmental changes. This article is protected by copyright. All rights reserved
... Chickens developed dose-dependent, temporary neurobehavioral abnormalities after oral imidacloprid exposure. While the neurobehavioral signs were comparable to those observed in birds in field and lab settings (Addy-Orduna, Brodeur, and Mateo 2019;Morrissey 2017, 2019;Millot et al. 2017), the effects were precisely documented in a doseresponse study which enabled determination of effect dose levels. The nervous system appeared to be a more sensitive indicator of sublethal effects than the immune system, as immunotoxicity was not detected. ...
Article
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Domestic chickens (Gallus gallus domesticus) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.50 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both the severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, either because the assays were insensitive, did not test relevant immune functions, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity.
... characteristics and unique action on pests (Sparks and Nauen, 2015;Wang et al., 2018). Soybean seeds prophylactically treated with neonicotinoid insecticides to deter pests have been planted over large areas of the United States (Ribeiro et al., 2018), and have been found to have negative impacts on birds (Addy-Orduna et al., 2019). In addition, serious problems such as agricultural pollution caused by ...
Article
Thiamethoxam (THIA) is a widely used pesticide. However, its effects on the growth and development of insects remain unclear. Herein, the lethal concentration 50 (LC50) of THIA (3.13 μg/mL for adults, 20.25 μg/mL for third-instar larvae) were identified. THIA (1/3 LC50) prolonged the time required for growth and development, and decreased the fecundity, the rates of pupation and eclosion, and lifespan of Drosophila. The uniform architecture of the compound eyes was disturbed. It also triggered DNA damage, and reduced the viability of fat body cells and hemocytes. Moreover, RNA-sequencing showed that differentially expressed genes in response to THIA were mainly related to stratum corneum development, immune function. Genes involved in stratum corneum proteins (Lcp65Ag3, Cpr65Ax1), hemocyte proliferation (RyR), and immune responses (IM4) were significantly induced. Genes associated with lipid metabolism (sxe2), lifespan (Atg7 and NalZ), pupa development (IIp8, Blimp-1), female fertility (Ddc), male mating behavior (ple), neural retina development (Nnad), was significantly downregulated. These findings provide a basis for further research to fully assess the hazards of exposure to neonicotinoid pesticides.
... Many recent studies confirmed toxic effects of NNIs to non-target organisms Lever et al. 2014;Addy-Orduna et al. 2019). Meanwhile, it is still necessary to summarise and understand general linkages of neonicotinoid pollution between terrestrial and aquatic ecosystems. ...
Chapter
Current rates of economic development are interrelated with an increase in environmental pollution. Among different contamination agents, modern insecticides such as neonicotinoids (NNIs) require precise attention in evaluation of losses and benefits. NNIs is relatively new class of systemic insecticides, being in use for about 20 years and embracing around 25% of global pesticide market. Currently there are several methods to apply NNIs to plants such as foliar sprays, soil drenches and seed treatments, and in recent years there has been a global shift towards seed treatment (seed dressing) rather than aerial spraying. The discovery of NNIs was considered as a milestone in the research on insecticides. Possessing chemical structure similar to nicotine and acting as agonists at insects’ acetylcholine receptors, NNIs demonstrate selective toxicity to invertebrates versus vertebrates. In addition, toxicity of NNIs in mammals is between one to three orders of magnitude lower than the toxicity caused by their predecessors: organophosphates, carbamates and pyrethroids. However, NNIs are mobile contaminants that can be transferred from plants to soils and water and induce diverse array of toxic effects in non-target organisms, even affecting animals not in contact with them directly. Surface- and groundwater may also act as vector for the transport of NNIs to untreated locations. The presence of NNIs in water bodies might facilitate their uptake by non-target plants present in littoral and riparian zones, with the potential threat to herbivorous insects. Leaching of NNIs to groundwater may imply their further distribution to other matrices, potentially leading to undesirable environmental issues. Pollinators and aquatic insects appear to be especially susceptible to these insecticides and chronic sublethal effects tend to be more prevalent than acute toxicity. Although a complete knowledge of the fate of NNIs in the environments is missing, authorities are starting to react to the threat they pose by limiting their use and application. Relevant improvements have been made in the field of the toxicity to non-target organisms. Studies that include factors such as mixture toxicity, field or semi-field exposures can make significant contribution to the further evaluating of costs-benefits of neonicotinoids.
... Many recent studies confirmed toxic effects of NNIs to non-target organisms Lever et al. 2014;Addy-Orduna et al. 2019). Meanwhile, it is still necessary to summarise and understand general linkages of neonicotinoid pollution between terrestrial and aquatic ecosystems. ...
Chapter
Alzheimer’s disease (AD) is the most common irreversible, progressive brain disorder which causes problems with memory, thinking and behavior with the age. Alzheimer's is the sixth leading cause of death in the United States. Combination of genetic, environmental factors like; chemical radiations, toxicants and mutagens are the main causes for neurodegeneration. Including with these factors some other events can produce early stages of AD, known as early stage AD, and lead to the same eventual distinctive final pathways in the late stages. Such stages could be characterized by neuroinflammation, oxidative stress and neurodegeneration. Furthermore, advanced glycation end products (AGEs) exacerbate amyloid beta (Aβ) has shown enhanced neurotoxicity. Considering these factors, we reinvestigated the role of AGE–RAGE interaction in AD pathology. Accumulation of AGEs is a normal feature of aging, but it becomes impaied in AD. AGEs are prominent in amyloid plaques and neurofibrillary tangles. Several lines of evidences demonstrate that AGE-RAGE interactions are critical for disease pathogenesis and it is at least partially responsible for extensive oxidative stress, inflammation, and neurodegeneration. Therefore many in vitro, in vivo and clinical studies have been focused on AGE–RAGE inhibitors, although their undesirable side effects and solubility issues may limits the usage. Therefore, it is needed to develop a potential, effective and multi-targeted inhibitors in order to prevent AGE induced neurological disorder.
... Many recent studies confirmed toxic effects of NNIs to non-target organisms Lever et al. 2014;Addy-Orduna et al. 2019). Meanwhile, it is still necessary to summarise and understand general linkages of neonicotinoid pollution between terrestrial and aquatic ecosystems. ...
Chapter
Nanotechnology, a science dealing with particles at nano scale, is currently used in many fields including environmental management and medicine for welfare of human being. The economic development and quality of life have been improved through nanotechnology. The Polycyclic aromatic hydrocarbons (PAHs) and other toxicants have higher affinity to scaveng by nanopartilces. The structural properties and surface chemistry of nanoparticles are the players, further, extremely high surface area to volume ratio results in multiple enhancement of many beneficial properties. Hence, we have followed a methodology to compare the binding efficiency of nanoparticles and cigarette smoke carcinogens with selected enzymes involved in DNA repair pathways. The molecular interactions have been accomplished using PatchDock server and interestingly got significant interacting results for our hypothesis. PatchDock results showed nanoparticles could be able to trap cigarette smoke carcinogens efficiently in the cellular system. The highest obtained binding efficiency between 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) versus Single wall carbon nanotube (SWcNT) is 2632 score in contrast with NNK versus Human MDC1 BRCT T2067D in complex (PDB ID: 3K05) shows 2454 score, which means NNK could interact with SWcNT more efficiently than 3K05. Another part of the study shows that the highest binding efficiency 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) versus SWcNT = 2746 score and NNAL versus Titanium dioxide (TiO2) Rutile = 2110 score in contract with NNAL versus Human Thymine DNA Glycosylase(PDB ID: 2RBA) shows 1696 score. It is also signified that NNAL interact with SWcNT and TiO2 rutile more efficiently than 2RBA. The results clearly signifying that SWcNT/TiO2 are binding with NNK/NNAL more efficiently than biomolecules.
... Risks of chemical insecticide use in urban landscape areas may include: (1) insecticide drift from foliar sprays [8], (2) leaching and runoff of insecticides into the water sources or drainage systems [9], (3) possibility of insecticide resistance development in the whitefly population due to prolonged use of the same chemical group [10,11], and (4) the negative impact on the non-target organisms, e.g. humans, domestic animals, natural enemies and pollinators [8,12,13]. ...
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A pilot study was conducted on a weeping fig, Ficus benjamina shrub hedge in a Florida urban landscape to determine the efficacy of a fungal biopesticide, PFR-97™ which contains blastospores of Isaria fumosorosea, and a neonicotinoid treatment (Admire Pro™) applied against the invasive ficus whitefly pest, Singhiella simplex (Singh). Post treatment, an ecological assessment of the study was conducted by observing the impact of the fungal biopesticide and neonicotinoid treatment on natural enemies, e.g., predators, parasitoids and enzootic fungal pathogens occurring in the whitefly-infested hedge. Both treatments provided a significant reduction in the whitefly population compared to control and were compatible with the natural enemies present. Various natural enemies including fungal entomopathogens were identified associated with the whitefly population infesting the weeping fig hedge. The parasitoids, Encarsia protransvena Viggiani and Amitus bennetti Viggiani & Evans combined parasitized a similar mean number of whitefly nymphs in both treatments and control; however, the number parasitized decreased over time. Natural enzootic fungi isolated from the ficus whitefly nymphs were I. fumosorosea, Purpureocillium lilacinum and Lecanicillium, Aspergillus and Fusarium species. Results from this pilot study suggest there is much potential for using repeated applications of the fungal biopesticide, PFR-97™ as a foliar spray compared to a neonicitionid as a soil drench for managing S. simplex on Ficus species for ≥28 days.
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Neonicotinoids (NEOs) are a class of insecticides that have high insecticidal activity and are extensively used worldwide. However, increasing evidence suggests their long-term residual in the environment and toxic effects on nontarget organisms. NEO residues are frequently detected in water and consequently have created increasing levels of pollution and pose significant risks to humans. Many studies have conducted surveys of NEO concentrations in water; however, few studies have focused on global systematic reviews or meta-analyses of NEO concentrations in water. In the present study, 43 published papers from 10 countries were indexed for a meta-analysis of the global NEO distribution in water. Among these studies, most focus on eastern Asia and North America, which are involved in intensive agricultural activities. The order of mean concentrations is identified as imidacloprid (119.542 ± 15.656 ng L ⁻¹ ) > nitenpyram (88.076 ± 27.144 ng L ⁻¹ ) > thiamethoxam (59.752 ± 9.068 ng L ⁻¹ ) > dinotefuran (31.086 ± 9.275 ng L ⁻¹ ) > imidaclothiz (24.542 ± 2.906 ng L ⁻¹ ) > acetamiprid (23.360 ± 4.015 ng L ⁻¹ ) > thiacloprid (11.493 ± 5.095 ng L ⁻¹ ). Moreover, the relationship between NEO concentrations and some environmental factors is analyzed. NEO concentrations increase with temperature, oxidation-reduction potential and the percentage of cultivated crops but decrease with stream discharge, pH, dissolved oxygen and precipitation. NEO concentrations show no significant relations to turbidity and conductivity. The purpose of this review is to conduct a meta-analysis on the concentration of NEOs in global waters based on published detections from several countries to extend knowledge on the application of NEOs.
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In this study, silver nanoparticles were prepared using new methodology and silver nanoparticles modified electrodes have been developed and characterized. The developed electrode is more catalytic towards the reduction of...
Article
The US Environmental Protection Agency (US EPA) and the Services (National Marine Fisheries Service, Fish and Wildlife Service) are required to assess the risks of pesticides undergoing registration or re‐registration to threatened and endangered (i.e., listed) species. Currently, the US EPA lacks a refined model to assess the potential risks of seed treatments to listed bird species. We developed the Endangered Species Assessment Seed Treatment Probabilistic Avian Risk Assessment Model (ESASeedPARAM) to incorporate species‐specific diets, body weights, and food ingestion rates for potentially exposed listed bird species. The model also incorporates information on dissipation of seed residues following planting, and metabolism and elimination by birds during exposure. The ESASeedPARAM estimates hourly intake from ingestion of treated seeds for up to 50 days following planting. For each simulated bird, maximum retained dose (=body burden) and maximum rolling average total daily intake are estimated for acute and chronic exposure, respectively. The model is probabilistic and estimates exposure and risk for 20 birds on each of 1000 fields. The model accounts for inter‐field variation in the amount of waste grain on the soil surface in tilled, reduced till and untilled fields. To estimate the fate of each bird from acute exposure, a random value is selected from the appropriate dose‐response relationship and compared to the maximum retained dose. If acute exposure exceeds the randomly chosen effects value, mortality is assumed. For chronic risk, the most sensitive No Observed Adverse Effects Level (NOAEL) and Lowest Observed Adverse Effects Level (LOAEL) for an apical endpoint (survival, growth, reproduction) are compared to maximum rolling average total daily intake. In this paper, we describe a case study conducted with the ESASeedPARAM for imidacloprid used as a seed treatment in wheat and soybean. This article is protected by copyright. All rights reserved.
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The extensive use of pesticides in agriculture has significantly impacted the environment and human health, as these pollutants are inadequately disposed of into water bodies. In addition, pesticides can cause adverse effects on humans and aquatic animals due to their incomplete removal from the aqueous medium by conventional wastewater treatments. Therefore, processes such as heterogeneous photocatalysis and adsorption by nanocomposites have received special attention in the scientific community due to their unique properties and ability to degrade and remove several organic pollutants, including pesticides. This report reviews the use of nanocomposites in pesticide adsorption and photocatalytic degradation from aqueous solutions. A bibliographic search was performed using the ScienceDirect, American Chemical Society (ACS), and Royal Society of Chemistry (RSC) indexes, using Boolean logic and the following descriptors: “pesticide degradation” AND “photocatalysis” AND “nanocomposites”; “nanocomposites” AND “pesticides” AND “adsorption”. The search was limited to research article documents in the last ten years (from January 2012 to June 2022). The results made it possible to verify that the most dangerous pesticides are not the most commonly degraded/removed from wastewater. At the same time, the potential of the supported nanocatalysts and nanoadsorbents in the decontamination of wastewater-containing pesticides is confirmed once they present reduced bandgap energy, which occurs over a wide range of wavelengths. Moreover, due to the great affinity of the supported nanocatalysts with pesticides, better charge separation, high removal, and degradation values are reported for these organic compounds. Thus, the class of the nanocomposites investigated in this work, magnetic or not, can be characterized as suitable nanomaterials with potential and unique properties useful in heterogeneous photocatalysts and the adsorption of pesticides.
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Insect kinins are endogenous, biologically active peptides with various physiological functions. The use of insect kinins in plant protection is being evaluated by many groups. Some kinins have been chosen as lead compounds for pest control. We previously reported an insect kinin mimic IV‐3 that had insecticidal activity. And by introducing a strong electron withdrawing group (‐CF3) on the benzene ring (Phe2), we discovered a compound, L7, with better activity than lead IV‐3. In this work, taking L7 as the lead compound, we designed and synthesized 13 compounds to evaluate the influence of position 4 (Trp4) of insect kinin on insecticidal activity, by replacing the H atom on tryptophan with ‐CH3 and ‐Cl, or substituting the indole ring of tryptophan with the benzene, naphthalene, pyridine, imidazole, cyclohexane, and alkyl carboxamides. The aphid bioassay results showed that the compounds M1, M3, and M5 were more active than the positive control, pymetrozine. Especially, replacing the side chain by an indole ring with 4‐Cl substitution (M1, LC50 = 0.0029 mmol/L) increased the aphicidal activity. The structure‐activity relationships (SAR) indicated that the side chain benzene ring at this position may be important to the aphicidal activity. In addition, the toxicity prediction by Toxtree and the toxicity experiments on Apis mellifera suggested that M1 was no toxicity risk on a non‐target organism. It could be used as a selective and bee‐friendly insecticide to control aphids.
Article
The decline of avian aerial insectivores has been greater than any other foraging guild and both climate change and agricultural intensification are leading hypotheses explaining this decline. Spring cold snaps are predicted to increase in frequency due to climate change, and factors associated with agricultural intensification (e.g., toxicological agents, simplification of agricultural landscapes, and reductions of insect prey) potentially exacerbates the negative effects of cold snaps on aerial insectivore nestling growth and body condition. We evaluated this hypothesis using repeated measures of Tree Swallow (Tachycineta bicolor (Vieillot, 1808)) nestling body mass and 9th primary length across an expansive gradient of agricultural intensification. Growth rate, asymptotic body mass, and near fledging 9th primary length were lower for nestlings in landscapes consisting of more agro-intensive monocultures. This 14-year data set of body measures occurring at 2, 6, 12 and 16 days of age showed that the negative impact of cold snaps on the growth of these two traits was stronger for nestlings reared in more agro-intensive landscapes. Our findings provide further evidence that two of the primary hypothesized drivers for the decline of many aerial insectivores may interact and aggravate their decline by reducing fledging survival.
Article
Neonicotinoids (NEOs) are a class of broad-spectrum insecticides dominant in the global market. They were distributed extensively in the environment and occurred frequently in humans. Potential health effects of NEOs, such as neurological toxicity and diabetes to non-targeted mammals, have raised concerns. This review summarizes analytical methods of NEOs in human samples, their internal exposure levels and composition profiles in urine, blood, hair, breast milk, saliva and tooth samples with global comparisons, and daily NEOs exposure dose and relative health risks. Urinary NEOs levels in Asian populations were substantially higher than those in the U.S. and Europe, which may be due to different dietary patterns and insecticide applications across regions. N-desmethyl acetamiprid, 5-hydroxy-imidacloprid and olefin-imidacloprid were dominant among detected NEOs. NEO metabolites exhibited higher detection frequencies and levels than their parent compounds in humans, while investigations on NEO metabolites remain much limited. Current exposure assessments mainly focused on short-term urine analysis, while biomaterials for long-term monitoring, such as hair, nail and other alternatives, should also be considered. Large-scale epidemiological studies are critically needed to elucidate potential health outcomes associated with NEOs exposure.
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Aerial insectivores show worldwide population declines coinciding with shifts in agricultural practices. Increasing reliance on certain agricultural practices is thought to have led to an overall reduction in insect abundance that negatively affects aerial insectivore fitness. The relationship between prey availability and the fitness of insectivores may thus vary with the extent of agricultural intensity. It is therefore imperative to quantify the strength and direction of these associations. Here we used data from an 11‐year study monitoring the breeding of Tree Swallows (Tachycineta bicolor) and the availability of Diptera (their main prey) across a gradient of agricultural intensification in southern Québec, Canada. This gradient was characterized by a shift in agricultural production, whereby landscapes composed of forage and pastures represented less agro‐intensive landscapes and those focusing on large‐scale arable row crop monocultures, such as corn (Zea mays) or soybean (Glycine max) that are innately associated with significant mechanization and agro‐chemical inputs, represented more agro‐intensive landscapes. We evaluated the landscape characteristics affecting prey availability, and how this relationship influences the fledging success, duration of the nestling period, fledgling body mass, and wing length as these variables are known to influence the population dynamics of this species. Diptera availability was greatest within predominately forested landscapes, while within landscapes dominated by agriculture, it was marginally greater in less agro‐intensive areas. Of the measured fitness and body condition proxies, both fledging success and nestling body mass were positively related to prey availability. The impact of prey availability varied across the agricultural gradient as fledging success improved with increasing prey levels within forage landscapes yet declined in more agro‐intensive landscapes. Finally, after accounting for prey availability, fledging success was lowest, nestling periods were the longest, and wing length of fledglings were shortest within more agro‐intensive landscapes. Our results highlight the interacting roles that aerial insect availability and agricultural intensification have on the fitness of aerial insectivores, and by extension how food availability may interact with other aspects of breeding habitats to influence the population dynamics of predators.
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Neonicotinoids is the most widely used insecticide, its contamination has led to sustained bird population declines. However, the toxicokinetic and underlying mechanisms of neonicotinoid toxicity in birds are largely unknown. Thiamethoxam (TMX), as a representative neonicotinoid insecticide, is now widely detected in most environmental medium and animal bodies. In this study, 5 mg/kg body weight TMX (potential environmental intake level) were orally administrated to male Japanese quails (Coturnix japonica).We found a rapid absorption, distribution, metabolism and elimination of TMX in quails in a period of 24 h, with the main metabolite, clothianidin (CLO), being extensively distributed and rapidly eliminated from tissues as well. The maximum plasm concentration of CLO was consistent with wild birds. Metabolomics analysis and followed determination of liver enzymes mRNA expression indicated the rapid metabolism was mediated mainly by CYPs and GSTs that involvedriboflavin metabolism and glutathione metabolism pathways upon TMX exposure. Molecular dynamic simulation showed the strongest binding interaction in quail CYP2H1-TMX and CYP3A12-CLO complexes among a set of CYPs-substrate. The present study elucidated toxicokinetic and underlying metabolic mechanisms of TMX in quails at environmentally-relevant concentration, the findings wouldfacilitate the understanding of potential risks of TMX and its metabolites to birds.
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Insecticides are pesticides used to control insects in agriculture, ornamental gardens, homes, and veterinary medicine. Although the toxic effects on the environment and the health of living beings are not fully understood, these pesticides have become the first options for crop protection in agriculture. After herbicides, insecticides are the most extensively used pesticides in agriculture, with large quantities consumed on every continent, primarily in America. Chlorpyrifos, carbaryl, and imidacloprid are among the top ten most used insecticides. Amidst organophosphates, chlorpyrifos has been reported to be used in over fifty food crops. Carbaryl is a carbamate employed as an insecticide, fungicide, herbicide, and nematicide. Similarly, neonicotinoids are the most used insecticide on a global scale. Neonicotinoids include imidacloprid, the second most frequently used pesticide, surpassed only by glyphosate. It is used because it is less toxic to humans. However, insects appear to be less resistant to its compounds. Evidence suggests that these insecticides persist in soils for a long time and have neurotoxic effects in animal species not intended to receive its consequences. Thus, this chapter’s aim is to describe these three pesticides effects and contrast them with the most recent findings regarding their neurotoxic effects in various animal species.
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Thiamethoxam (TMX), a representative neonicotinoids, is widely used for seed coating. The consumption of TMX-coated seeds posed threat to birds during crop sowing. The hepatotoxicity of TMX has been reported in mammals, however, no clear evidence showed TMX-induced toxic effects on bird liver. In this study, male Japanese quails (Coturnix japonica) were exposed to 20 or 200 mg/kg TMX-treated bird feed for 28 days. Results showed that Clothianidin (CLO), a TMX metabolite preferred to accumulate in quail plasma and liver, and inflammatory cell infiltration was found in quail livers. Oxidative stress-related biological processes were significantly enriched in both TMX treatment groups through transcriptomics analysis. Moreover, integrative analysis of transcriptomics and metabolomics indicated ferroptosis and DNA damage was implicated in hepatotoxicity caused by high- and low-concentration of TMX exposure, respectively. High-dose TMX treatment decreased CAT activity and GSH concentration and increased expression of the ferroptosis-related gene. In addition, the up-regulation of 8-OHdG concentration and DNA repair-related genes expression demonstrated low-dose TMX triggered oxidative DNA damage. The present results highlight the toxicity of TMX to bird livers and contribute to a better understanding of the TMX toxic mechanism in birds.
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The use of neonicotinoid insecticides leads to environmental problems such as accumulation and death of different insects and even bird species. In this work, we compared the SERS performance of Ag nanocubes- and nanospheres-based substrates for the analysis of thiacloprid, a neonicotinoid, reaching its detection at 1 mM using nanocubes as the active material.
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The present work is the first extensive study of large-scale pesticides research in wild animals. The investigation covered three game species: wild boar (n=42), roe deer (n=79) and deer (n=15) collected from north-eastern Poland. To characterize the 480 pesticides in muscle samples, LC-GC-MS/MS techniques were used. A total of 28 compounds were detected: 5 neonicotinoids, 6 organochlorine and 5 other insecticides, 9 fungicides and 4 herbicides, in the range of 0.1-85.3 ng g⁻¹. Over four hundred detections were done. The highest mean concentrations were as follows: anthraquinone (85.3 ng g⁻¹)>DDT-p,p’ (4.6 ng g⁻¹)>imidacloprid (4.3 ng g⁻¹)>permethrin (3.6 ng g⁻¹)>thiacloprid (2.8 ng g⁻¹). DDT and metabolites were the most frequently detected, followed by acetamiprid, tebuconazole, clothianidin and imidacloprid. Overall, 92% samples with residues were recorded, including 100% of wild boar, 88% of roe deer and 86% of deer. More than one pesticide (up to 9) was found in over 73% of the tested samples. The estimated chronic and acute risk to consumers of venison were very low (below 1% ADI and ARfD). This interdisciplinary study may be helpful for estimating ecological risk to wild animals and risk to consumers of wild animal products, and also as a source of biomonitoring data.
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The aim was to determine, for the first time, concentrations of 7 neonicotinoids (NEOs) and 5 metabolites in Sus scrofa from hunting areas in north-eastern Poland and assess the risk to consumers eating boar meat. 42 wild boar muscle samples were collected over a one-year period. The concentrations of 12 NEOs were determined by a fully validated LC-ESI-MS/MS protocol based on ultrasonic, freezing and cleanup EMR–lipid sample preparation. NEOs were present in over 83% of samples, 17% had no residue, and one pesticide was present in 36% of samples. Most often found were: clothianidin (35%), acetamiprid and imidacloprid (33%), thiacloprid (31%), thiamethoxam (9%), and the average concentrations were (ng g⁻¹): thiacloprid 6.2 > imidacloprid 5.7 > acetamiprid 4.6 > clothianidin 2.2 > thiacloprid 1.6 > thiamethoxam 1.0. Multi-residue samples were found, one with 7 and one with 5 NEOs. Two NEOs were present in 24%; 3 in 39% and 4 in 10% of samples. In the metabolic degradation of acetamiprid, imidacloprid and thiacloprid, it was observed that metabolites account for no more than 8.5% of the measured parent substance. Acetamiprid-n-desmethyl was noted most often (21%). Due to the detection of NEOs in a large proportion of samples, chronic and acute risk assessment were performed. The estimated chronic and acute risk for consumers from NEOs neonicotinoids through the consumption of wild boar was very low and amounted to respectively 0.02% of ADI and 0.86% of ARfD.
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This study investigated that to which extent selenium and vitamin E ameliorate toxic effects of thiamethoxam (TMX) in broiler birds. A total of (n = 100) chicks were divided into five equal groups. Sub-lethal doses of TMX 100 mg/kg BW were administered through crop tubing to groups A to D. Broiler chicks in groups B and C were supplemented with vitamin E (@150 mg/kg of BW) and selenium (@ 0.25 mg/kg of BW), respectively, through drinking water. Group D was supplemented with both antioxidants (vitamin E and selenium) whereas Group E served as a control. Blood samples from five birds of each group were collected at 14th, 28th, and 42nd days for hemato-biochemical studies. TMX treated birds showed clinical signs of respiratory, digestive, nervous, and behavioral upsets. TMX treated broilers exhibited a significant (p < 0.05) decrease in hematological indices like TEC, TLC, Hb, PCV, MCH, and MCHC. Biochemical parameters like TP, globulin, and albumin were decreased significantly while a significant (P <0.05) increase was observed in other parameters including such as AST, ALT, GGT, BUN, and creatinine. However, beneficial effects of combination of Vit E and selenium have been observed on hemato-biochemical parameters. It was concluded that TMX induces toxicopathological effects on hemato-biochemical parameters in broiler chicks which can be partially ameliorated by selenium and vitamin E.
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Pesticides are chemical substances intended for preventing or controlling pests. These are toxic substances which contaminate soil, water bodies and vegetative crops. Excessive use of pesticides may cause destruction of biodiversity. In plants, pesticides lead to oxidative stress, inhibition of physiological and biochemical pathways, induce toxicity, impede photosynthesis and negatively affect yield of crops. Increased production of reactive oxygen species like superoxide radicals, O−2 hydrogen peroxide, H2O2; singlet oxygen, O2; hydroxyl radical, OH−; and hydroperoxyl radical HO2−, causes damage to protein, lipid, carbohydrate and DNA within plants. Plant growth regulators (PGR) are recognized for promoting growth and development under optimal as well as stress conditions. PGR combat adverse effect by acting as chemical messenger and under complex regulation, enable plants to survive under stress conditions. PGR mediate various physiological and biochemical responses, thereby reducing pesticide-induced toxicity. Exogenous applications of PGRs, such as brassinosteroid, cytokinins, salicylic acid, jasmonic acid, etc., mitigate pesticide toxicity by stimulating antioxidant defense system and render tolerance towards stress conditions. They provide resistance against pesticides by controlling production of reactive oxygen species, nutrient homeostasis, increase secondary metabolite production, and trigger antioxidant mechanisms. These phytohormones protect plants against oxidative damage by activating mitogen-stimulated protein kinase cascade. Current study is based on reported research work that has shown the effect of PGR in promoting plant growth subjected to pesticide stress. The present review covers the aspects of pesticidal response of plants and evaluates the contribution of PGRs in mitigating pesticide-induced stress and increasing the tolerance of plants. Further, the study suggests the use of PGRs as a tool in mitigating effects of pesticidal stress together with improved growth and development.
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Since neonicotinoid insecticides were introduced to the agricultural market, evidence of the negative impacts of these systemic compounds on non-target species has accumulated. Birds are one of the largest groups of species to inhabit farmland, but the extent of neonicotinoid exposure in avian communities is poorly understood and very little is known about how any exposure may affect wild birds. Here, free-living gamebirds were used as a model group to measure the extent of avian exposure to the neonicotinoid clothianidin via seed treatment. During a typical sowing period of winter cereals treated with clothianidin, blood and liver samples were collected simultaneously from individual hunted gamebird carcasses, both pre- (n = 18) and post-sowing (n = 57) and were analysed for clothianidin via LC/MS-MS. Body weight, fat score and faecal parasite load were also quantified in the birds to ascertain whether any of these health parameters were associated with clothianidin exposure under field conditions. Clothianidin was detected in 6% of individuals sampled pre-sowing and 89% of individuals sampled post-sowing. The frequency of clothianidin detection in plasma samples and the concentration of clothianidin in liver and plasma samples decreased significantly between the first week and 2–4 weeks post-sowing. Faecal parasite load was positively associated with concentrations of clothianidin in the liver (but not plasma) of partridge species, but there was no association between clothianidin concentration and fat score or body weight, for either sample type. This study provides clear evidence that treated seed is a source of pesticide exposure for gamebirds following autumn sowing. These findings have implications for gamebirds worldwide where seed treatments are in use, and will aid the design of any future avian biomonitoring studies for agrochemical compounds.
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Pesticides coated to the seed surface potentially pose an ecological risk to granivorous birds that consume incompletely buried or spilled seeds. To assess the toxicokinetics of seeds treated with current-use fungicides, Japanese quail (Coturnix japonica) were orally dosed with commercially coated wheat seeds. Quail were exposed to metalaxyl, tebuconazole, and fludioxonil at either a low (0.0655, 0.0308, and 0.0328 mg/kg body weight, respectively) or high dose (0.196, 0.0925, and 0.0985 mg/kg body weight, respectively). Fungicides were rapidly absorbed and distributed to tissues. Tebuconazole was metabolized into t-butylhydroxy-tebuconazole. All compounds were eliminated to below detection limits within 24 h. The high detection frequencies observed in fecal samples potentially offers a noninvasive matrix to monitor pesticide exposure. Summing total body burden across plasma, tissue, and fecal samples, less than 9% of the administered dose was identified as the parent fungicide, demonstrating the importance to monitor both active ingredients and their metabolites in biological samples.
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Hazardous delays Neonicotinoids are a widely used group of pesticides that have been shown to have negative impacts on an increasing number of species, most notably pollinators. Eng et al. tested how exposure to these compounds influenced the behavior of a migrating songbird. Ingestion of field-realistic levels of neonicotinoid insecticides reduced feeding and accumulation of body mass and fat stores, which led to delayed departure from stopover sites. Such delays can lead to reduced migration survival and decreased reproductive success and therefore have the potential to impose population-level impacts. Science , this issue p. 1177
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In this study, an effective analytical method for simultaneous determination of thiamethoxam and its metabolite clothianidin in goji berry and soil was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The recoveries of the compounds in goji berry and soil at the levels of 0.005, 0.02, and 0.1 μg kg⁻¹ were 84.7–98.9% and the relative standard deviations (RSDs) were 0.9–3.2%. The limits of detection (LOD) for both compounds in goji berry and soil matrices were 0.001 mg kg⁻¹; the limits of quantification (LOQ) were 0.005 mg kg⁻¹ for both compounds in two matrices. The dissipation and final residual experiments in 2016 with the commercial formulation of dinotefuran • thiamethoxam 30% suspension concentrate (SC) was conducted in goji berries in northwest China (Qinghai, Gansu, Inner Mongolia, and Ningxia). Thiamethoxam was dissipated fast in goji plant ecosystem with half-lives were 1.08–1.01 and 2.04–4.25 days in goji berry and soil. The final residues of thiamethoxam were <0.005–0.382 and <0.005–1.120 mg kg⁻¹ in goji berry and soil, respectively.
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The impact of neonicotinoid insecticides on the health of bee pollinators is a topic of intensive research and considerable current debate [1]. As insecticides, certain neonicotinoids, i.e., N-nitroguanidine compounds such as imidacloprid and thiamethoxam, are as intrinsically toxic to bees as to the insect pests they target. However, this is not the case for all neonicotinoids, with honeybees orders of magnitude less sensitive to N-cyanoamidine compounds such as thiacloprid [2]. Although previous work has suggested that this is due to rapid metabolism of these compounds [2-5], the specific gene(s) or enzyme(s) involved remain unknown. Here, we show that the sensitivity of the two most economically important bee species to neonicotinoids is determined by cytochrome P450s of the CYP9Q subfamily. Radioligand binding and inhibitor assays showed that variation in honeybee sensitivity to N-nitroguanidine and N-cyanoamidine neonicotinoids does not reside in differences in their affinity for the receptor but rather in divergent metabolism by P450s. Functional expression of the entire CYP3 clade of P450s from honeybees identified a single P450, CYP9Q3, that metabolizes thiacloprid with high efficiency but has little activity against imidacloprid. We demonstrate that bumble bees also exhibit profound differences in their sensitivity to different neonicotinoids, and we identify CYP9Q4 as a functional ortholog of honeybee CYP9Q3 and a key metabolic determinant of neonicotinoid sensitivity in this species. Our results demonstrate that bee pollinators are equipped with biochemical defense systems that define their sensitivity to insecticides and this knowledge can be leveraged to safeguard bee health.
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Birds that travel long distances between their wintering and breeding grounds may be particularly susceptible to neurotoxic insecticides, but the influence of insecticides on migration ability is poorly understood. Following acute exposure to two widely used agricultural insecticides, imidacloprid (neonicotinoid) and chlorpyrifos (organophosphate), we compared effects on body mass, migratory activity and orientation in a seed-eating bird, the white-crowned sparrow (Zonotrichia leucophrys). During spring migration, sparrows were captured, held and dosed by gavage daily for 3 days with either the vehicle control, low (10% LD50) or high (25% LD50) doses of imidacloprid or chlorpyrifos and tested in migratory orientation trials pre-exposure, post-exposure and during recovery. Control birds maintained body mass and a seasonally appropriate northward orientation throughout the experiment. Imidacloprid dosed birds exhibited significant declines in fat stores and body mass (mean loss: −17% low, −25% high dose) and failed to orient correctly. Chlorpyrifos had no overt effects on mass but significantly impaired orientation. These results suggest that wild songbirds consuming the equivalent of just four imidacloprid-treated canola seeds or eight chlorpyrifos granules per day over 3 days could suffer impaired condition, migration delays and improper migratory direction, which could lead to increased risk of mortality or lost breeding opportunity.
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Background and purpose: Neonicotinoid insecticides are described as poor agonists of mammalian nicotinic acetylcholine receptors. In this paper, we provide evidence that they diffenrently act on mammalian nicotinic receptors. Experimental approach: Two-electrode voltage-clamp electrophysiology was used to characterized the pharmacology of neonicotinoid insecticides on α7 receptors expressed in Xenopus oocytes. Single and combined application of clothianidin, acetamiprid and thiamethoxam were tested. Results: The neonicotinoid insecticides, clothianidin and acetamiprid were partial agonists of mammalian neuronal α7 nicotinic receptors and thiamethoxam, a neonicotinoid insecticide, which is converted to clothianidin in insect and plant tissues had no effect. Pretreatment of 10 μM clothianidin and acetamiprid with 100 μM acetylcholine, significantly enhanced the subsequent acetylcholine-evoked currents whereas, 10 μM thiamethoxam reduced acetylcholine-induced current amplitudes. Moreover, the combinations of the three neonicotinoids decreased the ACh evoked currents. Conclusions and implications: The present findings suggest that neonicotinoid insecticides differently affect α7 nicotinic acetylcholine receptors and can modulate acetylcholine-induced current. In final, the data indicate a previous unknown modulation of mammalian α7 receptors by combined application of clothianidin, acetamiprid and thiamethoxam.
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The large-scale use of neonicotinoid insecticides has raised growing concerns about their potential adverse effects on farmland birds, and more generally on biodiversity. Imidacloprid, the first neonicotinoid commercialized, has been identified as posing a risk for seed-eating birds when it is used as seed treatment of some crops since the consumption of a few dressed seeds could cause mortality. But evidence of direct effects in the field is lacking. Here, we reviewed the 103 wildlife mortality incidents reported by the French SAGIR Network from 1995 to 2014, for which toxicological analyses detected imidacloprid residues. One hundred and one incidents totalling at least 734 dead animals were consistent with an agricultural use as seed treatment. Grey partridges (Perdix perdix) and ?pigeons? (Columba palumbus, Columbalivia and Columba oenas) were the main species found. More than 70% of incidents occurred during autumn cereal sowings. Furthermore, since there is no biomarker for diagnosing neonicotinoid poisonings, we developed a diagnostic approach to estimate the degree of certainty that these mortalities were due to imidacloprid poisoning. By this way, the probability that mortality was due to poisoning by imidacloprid-treated seeds was ranked as at least ?likely? in 70% of incidents. As a result, this work provides clear evidence to risk managers that lethal effects due to the consumption by birds of imidacloprid-treated seeds regularly occur in the field. This in turn raises the question of the effectiveness of the two main factors (seed burying and imidacloprid-treated seeds avoidance) that are supposed to make the risk to birds negligible. Risk factors and the relevance of mitigation measures are discussed. Electronic supplementary material The online version of this article (doi:10.1007/s11356-016-8272-y) contains supplementary material, which is available to authorized users.
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There is growing concern over the risk to bee populations from neonicotinoid insecticides and the long-term consequences of reduced numbers of insect pollinators to essential ecosystem services and food security. Our knowledge of the risk of neonicotinoids to bees is based on studies of imidacloprid and thiamethoxam and these findings are extrapolated to clothianidin based on its higher potency at nicotinic acetylcholine receptors. This study addresses the specificity and consequences of all three neonicotinoids to determine their relative risk to bumblebees at field-relevant levels (2.5 ppb). We find compound-specific effects at all levels (individual cells, bees and whole colonies in semi-field conditions). Imidacloprid and clothianidin display distinct, overlapping, abilities to stimulate Kenyon cells, indicating the potential to differentially influence bumblebee behavior. Bee immobility was induced only by imidacloprid, and an increased vulnerability to clothianidin toxicity only occurred following chronic exposure to clothianidin or thiamethoxam. At the whole colony level, only thiamethoxam altered the sex ratio (more males present) and only clothianidin increased queen production. Finally, both imidacloprid and thiamethoxam caused deficits in colony strength, while no detrimental effects of clothianidin were observed. Given these findings, neonicotinoid risk needs to be considered independently for each compound and target species.
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A comprehensive review of published and previously unpublished studies was performed to evaluate the neonicotinoid insecticides for evidence of developmental neurotoxicity (DNT). These insecticides have favorable safety profiles, due to their preferential affinity for nicotinic receptor (nAChR) subtypes in insects, poor penetration of the mammalian blood-brain barrier, and low application rates. Nevertheless, examination of this issue is warranted, due to their insecticidal mode of action and potential exposure with agricultural and residential uses. This review identified in vitro, in vivo, and epidemiology studies in the literature and studies performed in rats in accordance with GLP standards and EPA guidelines with imidacloprid, acetamiprid, thiacloprid, clothianidin, thiamethoxam, and dinotefuran, which are all the neonicotinoids currently registered in major markets. For the guideline-based studies, treatment was administered via the diet or gavage to primiparous female rats at three dose levels, plus a vehicle control (≥20/dose level), from gestation day 0 or 6 to lactation day 21. F1 males and females were evaluated using measures of motor activity, acoustic startle response, cognition, brain morphometry, and neuropathology. The principal effects in F1 animals were associated with decreased body weight (delayed sexual maturation, decreased brain weight, and morphometric measurements) and acute toxicity (decreased activity during exposure) at high doses, without neuropathology or impaired cognition. No common effects were identified among the neonicotinoids that were consistent with DNT or the neurodevelopmental effects associated with nicotine. Findings at high doses were associated with evidence of systemic toxicity, which indicates that these insecticides do not selectively affect the developing nervous system.
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To better understand the fate and transport of neonicotinoid insecticides, water samples were collected from streams across the United States. In a nationwide study, at least one neonicotinoid was detected in 53% of the samples collected, with imidacloprid detected most frequently (37 %), followed by clothianidin (24 %), thiamethoxam (21 %), dinotefuran (13 %), acetamiprid (3 %) and thiacloprid (0 %). Clothianidin and thiamethoxam concentrations were positively related to the percentage of the land use in cultivated crop production and imidacloprid concentrations were positively related to the percentage of urban area within the basin. Additional sampling was also conducted in targeted research areas to complement these national-scale results, including determining: (1) neonicotinoid concentrations during elevated flow conditions in an intensely agricultural region; (2) temporal patterns of neonicotinoids in heavily urbanised basins; (3) neonicotinoid concentrations in agricultural basins in a nationally important ecosystem; and (4) in-stream transport of neonicotinoids near a wastewater treatment plant. Across all study areas, at least one neonicotinoid was detected in 63% of the 48 streams sampled.
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Chronic exposure to widely used insecticides kills bees and many other invertebrates
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The side effects of the current global use of pesticides on wildlife, particularly at higher levels of biological organization: populations, communities and ecosystems, are poorly understood (Kohler and Triebskorn 2013). Here, we focus on one of the problematic groups of agrochemicals, the systemic insecticides fipronil and those of the neonicotinoid family. The increasing global reliance on the partly prophylactic use of these persistent and potent neurotoxic systemic insecticides has raised concerns about their impacts on biodiversity, ecosystem functioning and ecosystem services provided by a wide range of affected species and environments. The present scale of use, combined with the properties of these compounds, has resulted in widespread contamination of agricultural soils, freshwater resources, wetlands, non-target vegetation and estuarine and coastal marine systems, which means that many organisms inhabiting these habitats are being repeatedly and chronically expose ...
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Since their discovery in the late 1980s, neonicotinoid pesticides have become the most widely used class of insecticides worldwide, with large-scale applications ranging from plant protection (crops, vegetables, fruits), veterinary products, and biocides to invertebrate pest control in fish farming. In this review, we address the phenyl-pyrazole fipronil together with neonicotinoids because of similarities in their toxicity, physicochemical profiles, and presence in the environment. Neonicotinoids and fipronil currently account for approximately one third of the world insecticide market; the annual world production of the archetype neonicotinoid, imidacloprid, was estimated to be ca. 20,000 tonnes active substance in 2010. There were several reasons for the initial success of neonicotinoids and fipronil: (1) there was no known pesticide resistance in target pests, mainly because of their recent development, (2) their physicochemical properties included many advantages over previous generations of insecticides (i.e., organophosphates, carbamates, pyrethroids, etc.), and (3) they shared an assumed reduced operator and consumer risk. Due to their systemic nature, they are taken up by the roots or leaves and translocated to all parts of the plant, which, in turn, makes them effectively toxic to herbivorous insects. The toxicity persists for a variable period of time — depending on the plant, its growth stage, and the amount of pesticide applied. Awide variety of applications are available, including the most common prophylactic non-Good Agricultural Practices (GAP) application by seed coating. As a result of their extensive use and physicochemical properties, these substances can be found in all environmental compartments including soil, water, and air. Neonicotinoids and fipronil operate by disrupting neural transmission in the central nervous system of invertebrates. Neonicotinoids mimic the action of neurotransmitters, while fipronil inhibits neuronal receptors. In doing so, they continuously stimulate neurons leading ultimately to death of target invertebrates. Like virtually all insecticides, they can also have lethal and sublethal impacts on non-target organisms, including insect predators and vertebrates. Furthermore, a range of synergistic effects with other stressors have been documented. Here, we review extensively their metabolic pathways, showing how they form both compound-specific and common metabolites which can themselves be toxic. These may result in prolonged toxicity. Considering their wide commercial expansion, mode of action, the systemic properties in plants, persistence and environmental fate, coupled with limited information about the toxicity profiles of these compounds and their metabolites, neonicotinoids and fipronil may entail significant risks to the environment. A global evaluation of the potential collateral effects of their use is therefore timely. The present paper and subsequent chapters in this review of the global literature explore these risks and show a growing body of evidence that persistent, low concentrations of these insecticides pose serious risks of undesirable environmental impacts.
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Large-scale use of the persistent and potent neonicotinoid and fipronil insecticides has raised concerns about risks to ecosystem functions provided by a wide range of species and environments affected by these insecticides. The concept of ecosystem services is widely used in decision making in the context of valuing the service potentials, benefits, and use values that well-functioning ecosystems provide to humans and the biosphere and, as an endpoint (value to be protected), in ecological risk assessment of chemicals. Neonicotinoid insecticides are frequently detected in soil and water and are also found in air, as dust particles during sowing of crops and aerosols during spraying. These environmental media provide essential resources to support biodiversity, but are known to be threatened by long-term or repeated contamination by neonicotinoids and fipronil. We review the state of knowledge regarding the potential impacts of these insecticides on ecosystem functioning and services provided by terrestrial and aquatic ecosystems including soil and freshwater functions, fisheries, biological pest control, and pollination services. Empirical studies examining the specific impacts of neonicotinoids and fipronil to ecosystem services have focused largely on the negative impacts to beneficial insect species (honeybees) and the impact on pollination service of food crops. However, here we document broader evidence of the effects on ecosystem functions regulating soil and water quality, pest control, pollination, ecosystem resilience, and community diversity. In particular, microbes, invertebrates, and fish play critical roles as decomposers, pollinators, consumers, and predators, which collectively maintain healthy communities and ecosystem integrity. Several examples in this review demonstrate evidence of the negative impacts of systemic insecticides on decomposition, nutrient cycling, soil respiration, and invertebrate populations valued by humans. Invertebrates, particularly earthworms that are important for soil processes, wild and domestic insect pollinators which are important for plant and crop production, and several freshwater taxa which are involved in aquatic nutrient cycling, were all found to be highly susceptible to lethal and sublethal effects of neonicotinoids and/or fipronil at environmentally relevant concentrations. By contrast, most microbes and fish do not appear to be as sensitive under normal exposure scenarios, though the effects on fish may be important in certain realms such as combined fish-rice farming systems and through food chain effects. We highlight the economic and cultural concerns around agriculture and aquaculture production and the role these insecticides may have in threatening food security. Overall, we recommend improved sustainable agricultural practices that restrict systemic insecticide use to maintain and support several ecosystem services that humans fundamentally depend on.
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Concerns over the role of pesticides affecting vertebrate wildlife populations have recently focussed on systemic products which exert broad-spectrum toxicity. Given that the neonicotinoids have become the fastest-growing class of insecticides globally, we review here 150 studies of their direct (toxic) and indirect (e.g. food chain) effects on vertebrate wildlife-mammals, birds, fish, amphibians and reptiles. We focus on two neonicotinoids, imidacloprid and clothianidin, and a third insecticide, fipronil, which also acts in the same systemic manner. Imidacloprid and fipronil were found to be toxic to many birds and most fish, respectively. All three insecticides exert sub-lethal effects, ranging from genotoxic and cytotoxic effects, and impaired immune function, to reduced growth and reproductive success, often at concentrations well below those associated with mortality. Use of imidacloprid and clothianidin as seed treatments on some crops poses risks to small birds, and ingestion of even a few treated seeds could cause mortality or reproductive impairment to sensitive bird species. In contrast, environmental concentrations of imidacloprid and clothianidin appear to be at levels below those which will cause mortality to freshwater vertebrates, although sub-lethal effects may occur. Some recorded environmental concentrations of fipronil, however, may be sufficiently high to harm fish. Indirect effects are rarely considered in risk assessment processes and there is a paucity of data, despite the potential to exert population-level effects. Our research revealed two field case studies of indirect effects. In one, reductions in invertebrate prey from both imidacloprid and fipronil uses led to impaired growth in a fish species, and in another, reductions in populations in two lizard species were linked to effects of fipronil on termite prey. Evidence presented here suggests that the systemic insecticides, neonicotinoids and fipronil, are capable of exerting direct and indirect effects on terrestrial and aquatic vertebrate wildlife, thus warranting further review of their environmental safety.
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Despite the use of pigeons (Columba livia domestica) since 2500 BC by man for meat production, ornamentals, sports and experimental animals, limited information is available on their nutrient requirements and feeding. This could partly be attributed to the rearing of growing chicks (squabs) to mature body weight at 28 days by the parents. Squabs have an extraordinary high rate of maturing (0.1466 to 0.1945 g/d) in comparison to other domesticated avian species such as poultry (0.0450 g/d) and quail (0.077 to 0.097 g/d). This growth rate is achieved by regurgitation of a holocrine substance (crop milk) by both parents, formed in response to prolactin secretion and triggered by brooding. Crop milk consists primarily of protein (11.0 to 18.8% on as is basis) and fat (4.5 to 12.7% on as is basis), and lacks significant levels of carbohydrates. Furthermore, adult pigeons are mainly fed mixtures of whole grains. Special feeding characteristics inherent to the pigeon thus prevent extrapolation of nutrient requirements determined with other avian species. A dietary crude protein content of between 12 and 18%, and metabolizable energy (ME) content of around 12 MJ/kg, based on production of offspring, is recommended for feeding of adult pigeons. Apparent metabolizable energy, corrected for nitrogen retention (AMEn) for maize (14.76 MJ/kg), barley (12.36 MJ/kg), sorghum (13.87 MJ/kg) and peas (14.01 MJ/kg) did not differ substantially from values derived for poultry. Pigeons could utilize lipids better than carbohydrates as energy sources. Feed additives and suggestions for future research are discussed.
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Outbreaks of infectious diseases in honey bees, fish, amphibians, bats and birds in the past two decades have coincided with the increasing use of systemic insecticides, notably the neonicotinoids and fipronil. A link between insecticides and such diseases is hypothesised. Firstly, the disease outbreaks started in countries and regions where systemic insecticides were used for the first time, and later they spread to other countries. Secondly, recent evidence of immune suppression in bees and fish caused by neonicotinoids has provided an important clue to understand the sub-lethal impact of these insecticides not only on these organisms, but probably on other wildlife affected by emerging infectious diseases. While this is occurring, environmental authorities in developed countries ignore the calls of apiarists (who are most affected) and do not target neonicotinoids in their regular monitoring schedules. Equally, scientists looking for answers to the problem are unaware of the new threat that systemic insecticides have introduced in terrestrial and aquatic ecosystems.
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EXECUTIVE SUMMARY The neonicotinoids represent a relatively new group of insecticides. They were introduced in the early 1990s to counter widespread resistance in insect pests and increasing health and safety objections to the organophosphorous insecticides. Although of lower acute toxicity to vertebrates than the latter, the neonicotinoids’ longer persistence, high water solubility, runoff and leaching potential as well as their very high toxicity to pollinators are placing them under increasing public and political scrutiny, especially now that they have become the most widely used pesticides in the world. Their toxicity to pollinators has brought them the most attention so far and has dominated the recent concerns of regulatory institutions worldwide. The intent of this report is to review the risk that neonicotinoids pose to birds. Birds have borne more than their fair share of impacts from pesticides – from the early issues of eggshell thinning with DDT to the extensive mortality caused by the organophosphorous and carbamate insecticides that followed. Some researchers have suggested that birds may already be affected by neonicotinoids and that, at least in Europe, bird population declines can be blamed on these popular insecticides. The main products reviewed here are acetamiprid, imidacloprid, thiacloprid, clothianidin and thiamethoxam. Minor compounds include dinotefuran, nitenpyram and nithiazine. For the sake of comparison, this report will discuss, where appropriate, a number of older insecticides that the neonicotinoids have replaced. This includes the organophosphorous insecticides diazinon, chlorpyrifos, malathion, terbufos and methamidophos, the carbamate insecticides carbofuran, methomyl, the pyrethroids tefluthrin and deltamethrin as well as the seed treatment insecticide carbathiin. The report will emphasize US regulatory history although it will make reference to Canadian and EU regulatory reviews where relevant. For ease of consultation, summary points made here are detailed in the body of the report under the same section heading: 1. The history of neonicotinoid registrations highlights many of the critical failings of our current pesticide registration system. Regulatory agencies in both the US and Canada (and to some extent in Europe as well) exhibited a conflicted approach to the neonicotinoid class of compounds – on the one hand expressing serious concerns about the persistence, mobility and toxicity of the products – on the other hand, granting registrations in an ever-widening range of crops and non-agricultural use sites. There is evidence the neonicotinoids got a very ‘soft ride’ through registration. Based on the existing record, registration decisions concerning the neonicotinoid insecticides were overwhelmingly positive despite a consistent record of cautionary warnings from the scientists involved in the assessment process. Increased concerns in the scientific and popular literature over imidacloprid, clothianidin and other neonicotinoid insecticides did not deter pesticide manufacturers, who appeared to be in a race to register as many uses as possible. It looks as if the USEPA and other regulatory agencies consistently approved registrations despite their own scientists’ repeated and ever-growing concerns. It is relevant to ask why we conduct scientific evaluations of products if those evaluations have little or no bearing on the registration decisions that are made, and when staff scientists warning of ‘major risk concerns’ appear to be ignored. Even though several early reviews of the first neonicotinoid, imidacloprid, correctly identified Neonicotinoid Insecticides and Birds 6 issues of bird and mammal toxicity, persistence, runoff/leaching and aquatic toxicity, regulators failed to apply some of the lessons learned in the 1990s with imidacloprid to more recently developed compounds such as clothianidin and thiamethoxam. They also failed (and continue to fail) to consider the impact of combined neonicotinoid residues in the environment. Regulators have tended to place inordinate faith in precautionary labelling to mitigate very serious terrestrial and aquatic risks. 2. The acute toxicity of neonicotinoids to birds is lower than the acute toxicity of many of the insecticides they have replaced, notably the organophosphorous and carbamate insecticides. However, EPA and other regulatory agencies worldwide have underestimated the toxicity of these compounds to birds. This undervaluation is partly because the risk assessment methods fail to account sufficiently for interspecies variation in toxicity. Depending on the specific insecticide, we have found that EPA underestimates toxicity by 1.5 - 10 fold if the intent of the exercise is to protect most potentially exposed bird species, and not merely mallards and bobwhites, the two test species. In addition, there is some evidence that the neonicotinoid insecticides will debilitate birds at a much reduced fraction of a lethal dose compared to other pesticides and this debilitation will be longer-lasting. Small non-lethal doses are likely to cause partial paralysis and other sub-lethal effects in birds. These effects slip under the radar screen in regulatory assessments based entirely on lethal levels. 3. The chronic/reproductive toxicity of neonicotinoids to birds is high. This was recognised very early on in the regulatory reviews of the various active ingredients. Yet high reproductive toxicity in birds is typically ignored in the pesticide review process – whether for neonicotinoids or for other pesticides. Many pesticides fail the current reproduction screen, and many uncertainties exist surrounding the extrapolation of laboratory data to actual field conditions. These problems are not new but regulatory agencies have failed to address the situation. Because the neonicotinoids are systemic and persistent in soils, and because several are used as seed treatment chemicals, they are available to birds in a chronic fashion, making their potential to affect reproduction an even greater concern. The standard tests carried out by manufacturers place reproductive effects at dosing levels ranging from 2 to 13 mg/kg/day depending on the product. This level of exposure is easily achieved with seed treatment chemicals. However, very recent toxicological information from Japan suggests that testicular function in male birds as well as embryonic development in the offspring of exposed males is affected at levels much lower than indicated from these standard reproduction tests. 4. Of particular concern to birds are those compounds that are used as seed treatments, primarily imidacloprid, clothianidin, thiamethoxam and acetamiprid. Regardless of the exact label directions and requirements, seed-treatment chemicals are widely available to birds. Seeds are never fully covered with soil, making them easy to find by foraging birds. Spills are commonplace with current machinery. And many species have the ability to scrape and dig for planted seed. Seed treatments, by definition, will result in a high exposure situation for birds (as well as for small mammal species not discussed in this report). Both the EPA in the US and Pest Neonicotinoid Insecticides and Birds 7 Management Regulatory Agency (PMRA) in Canada have failed at times to consider this high exposure potential in their assessments. 5. The amount of insecticide adhering to the average corn (maize) seed can result in acute intoxications in birds with all three registered products – imidacloprid, clothianidin and thiamethoxam. With imidacloprid, a single seed may prove lethal for an average-sized bird (e.g. blue jay-sized) likely to be picking up whole corn seed from seeded fields. A few seeds only are required in the case of clothianidin or thiamethoxam. Indeed, we believe that imidacloprid is too acutely toxic to be used as a seed treatment insecticide on any seed type based on our assessment of its use in cereals and oilseeds. Acute intoxications in wheat or canola are less likely with clothianidin or thiamethoxam because these neonicotinoids are less acutely toxic to birds. The birds would need to ingest a greater number of the treated seeds to receive a lethal dose. However, based on chronic/reproduction endpoints, all seed treatments are predicted to cause effects given the very small number of seeds (as low as 1/10 of a seed per day during egg laying season) needing to be ingested to push birds into a ‘critical range’ where reproductive effects are expected. The main uncertainty here is how long the seeds will be available to birds and how long dosing is necessary before the type of effects seen in the laboratory will be seen in the wild. There are huge uncertainties – for instance what types of effects might be seen in altricial species (those in which the newly-hatched young are born relatively helpless, such as most passerines, or perching birds) and how this differs from effects seen in precocial species (in which the newly hatched young are relatively mature, such as ducks and geese, grouse and pheasants). Based on our current understanding and risk assessment procedures in place, the neonicotinoids as a group have a high potential to affect avian reproduction. This is due in large part to the very high exposure potential that seed treatment chemicals represent and the persistent nature of the neonicotinoids. A publication currently in press advances the hypothesis that the neonicotinoids are a contributory factor to many wildlife diseases through immune suppression. The authors make this claim on the basis of geographic and temporal associations. The sheer scale and seriousness of the issue demands that this hypothesis be investigated more fully. Despite industry claims, the neonicotinoids are not repellant to birds. Any demonstrated avoidance can be explained by hesitation before a new food source or post-ingestion intoxication and illness. Neither is sufficient to spare birds from either acute or chronic effects. There are parallels with the cholinesterase-inhibiting insecticides where repellency was similarly thought to reduce in-field risks. For example, the organophosphorous insecticide diazinon is extremely well avoided in the laboratory. Yet, thousands of geese and other species have grazed their way to an early death on diazinon-treated turf. 6. The link between impacts on the insect food of birds and declines of bird species is difficult to establish unequivocally, save for the evidence linking the grey partridge to pesticide use in the UK. A review of the existing literature suggests that it is difficult to predict the relative importance of food supply during the breeding season (i.e. when an insect food base is critical) compared to other risks such as habitat loss, food supply during migration and during winter, predation or Neonicotinoid Insecticides and Birds 8 even direct losses from poisoning or disturbances such as mowing or tillage. Each species responds to a different set of stressors and it is likely that many of the declines have multiple causes. Nevertheless, it would be foolhardy to argue that dramatic losses of insect biomass from ecosystems is not going to have potential consequences on the integrity of those ecosystems and on the species that depend to varying degrees on the spring-summer flush of insect food. The impacts on terrestrial food chains from neonicotinoid (and other systemic) insecticides may be much longer-lived and pernicious than those we have seen with non-systemic products. Generally speaking, an over-efficient removal of insects in crop fields is seldom seen as a matter of serious concern by regulators – especially in North America. The indirect impacts of pesticides are not considered in registration reviews – whether in the US or anywhere else in the world. In his book, Dutch toxicologist Henk Tennekes (2010) makes the case that the contamination of surface water by neonicotinoids is so widespread in the Netherlands (and possibly elsewhere in Europe), that loss of insect biomass on a continental scale is behind many of the widespread declines that are being seen, be they of marsh birds, heath or meadow birds or even coastal species. This suggests that we should be looking at possible links between neonicotinoid insecticides and birds, not on a farm scale, but in the context of whole watersheds and regions. Impacts from the neonicotinoids may very well be further afield than the arable area on which they are used, and many of those impacts may be mediated through the aquatic environment. Because aquatic impacts are considered during product registration reviews, it is reasonable to ask whether the potential impact of neonicotinoids to aquatic life has been assessed correctly. 7. Unfortunately, North American regulators have greatly underestimated the toxicity of imidacloprid and other neonicotinoids to aquatic invertebrates. Reference doses are set using outdated methodology which has more to do with a game of chance than with a rigorous scientific process. A complete disregard for the peer-reviewed literature is a constant factor throughout the history of neonicotinoid assessments. For imidacloprid, we believe that a scientifically defensible reference level (a water concentration at which undesirable effects are likely to be seen in reasonably sensitive species) for acute invertebrate effects (following short term exposure) is approximately 0.2 ug/l. European regulators acknowledge that acute effects are likely at levels exceeding 0.5 ug/l. In contrast, the EPA’s regulatory and non-regulatory reference levels are set at 35 ug/l. Similarly, a reasonable reference level for effects following chronic exposure is at least an order of magnitude lower, or between 0.01 and 0.03 ug/l rather than the 0.5 ug/l used in the U.S.. EPA’s approach to the assessment of aquatic risk is scientifically unsound and places aquatic environments at risk. In addition, there is evidence that risk managers at EPA have ignored aquatic risk ratios that exceeded the usual level of concern, notwithstanding the fact that those risk ratios were grossly underestimated in the first place. Based on the relative sensitivity of aquatic insects tested with several of the neonicotinoid insecticides, we suggest that these reference levels should also apply to the other neonicotinoid insecticides, notably acetamiprid, thiacloprid, clothianidin and thiamethoxam. In fact, because of their similarity in mode of action, the above reference levels should apply to the sum of all residues for all parent neonicotinoid compounds as well as some of the degradates. Neonicotinoid Insecticides and Birds 9 Neonicotinoid insecticides may be totally unprecedented in the history of pesticide registration in that measured groundwater contamination levels have been high enough to cause aquatic impacts. Data on surface water contamination from surveys to date, notably from California and from the Canadian Prairies, indicate that concentrations of several of the neonicotinoid insecticides are high enough to be causing impacts in aquatic food chains. Data from other jurisdictions (e.g. the Netherlands) show even higher levels of contamination. It is clear that neonicotinoids have often replaced other insecticides of higher short-term toxicity to aquatic life – especially fish. However, the mode of action of neonicotinoids, which entails a cumulative irreversible action and delayed effects in invertebrates, as well as their persistence in the environment, makes them particularly worrisome. It is clear that we are witnessing contamination of the aquatic environment at levels that will affect aquatic food chains. This has a potential to affect consumers of those aquatic resources, be they birds, fish or amphibians. In conclusion, policymakers and the public should be very concerned about the impact of neonicotinoid insecticides on birds and on the broader environment. Specifically, we should be concerned that:  regulatory procedures are scientifically deficient and prone to the vagaries of chance  risk managers appear to place minimal weight on concerns raised by environmental scientists who carry out the scientific evaluations of the products  despite all the red flags, regulators are adding to the list of permissible uses  neonicotinoids – the most heavily used insecticides in the world – are systemic products that are extremely persistent and very much prone to runoff and groundwater infiltration  some neonicotinoids are capable of causing lethal intoxications and all are predicted to cause reproductive dysfunction in birds  where we have looked, we have found broad-scale aquatic contamination at levels expected to cause impacts on aquatic food chains.  any future re-evaluation of these products appears to focus solely on pollinator toxicity. The seriousness of pollinator losses should not be underestimated, but there is much more at stake. A moratorium on any further use expansion is currently being discussed in the EU and Member States. Some countries have moved forward on limited cancellations. The North American regulatory system needs to act rather than continue to ignore evidence of widespread environmental damage. There is evidence that US regulators waited far too long to impose needed restrictions on the toxic insecticides responsible for millions of bird deaths per year (Mineau 2004) and that this is one of the more plausible reasons for the decline of grassland/farmland birds in North America (Mineau and Whiteside, 2013). The neonicotinoids have largely replaced that older generation of chemicals. We are urging regulators to take seriously the red flags raised by this persistent, cumulative, irreversibly-acting new class of pesticides.
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