An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems.

New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous Worldwide Integrated Assessment (WIA) in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the recent research has focused on bees and the sublethal and ecological impacts these insecticides have on pollinators. Toxic effects on other invertebrate taxa also covered predatory and parasitoid natural enemies and aquatic arthropods. Little new information has been gathered on soil organisms. The impact on marine and coastal ecosystems is still largely uncharted. The chronic lethality of neonicotinoids to insects and crustaceans, and the strengthened evidence that these chemicals also impair the immune system and reproduction, highlights the dangers of this particular insecticidal class (neonicotinoids and fipronil), with the potential to greatly decrease populations of arthropods in both terrestrial and aquatic environments. Sublethal effects on fish, reptiles, frogs, birds, and mammals are also reported, showing a better understanding of the mechanisms of toxicity of these insecticides in vertebrates and their deleterious impacts on growth, reproduction, and neurobehaviour of most of the species tested. This review concludes with a summary of impacts on the ecosystem services and functioning, particularly on pollination, soil biota, and aquatic invertebrate communities, thus reinforcing the previous WIA conclusions (van der Sluijs et al. 2015).

Occurrence of Neonicotinoids in Chinese Apiculture and a Corresponding Risk Exposure Assessment.

Neonicotinoids are the most widely used insecticides worldwide, but there is mounting evidence demonstrating that they have adverse effects on nontarget organisms. However, little is known about the extent of environmental neonicotinoids contamination in China. In this study, a total of 693 honey samples from across China, from both Apis melifera and Apis cerana, were analyzed to examine neonicotinoid concentrations and their geographical distribution, and correlation with the primary plant species from which the honey was obtained. Furthermore, chronic and acute exposure risk and risk ranking for humans eating honey were investigated, and risks to bees were also considered. The results revealed that 40.8% of the samples contained at least one of the five neonicotinoids tested. Honeys from commercial crops were found to be more frequently contaminated with neonicotinoids than those from noncommercial crops. Honey samples from Apis mellifera were more frequently contaminated than those from Apis cerana. The concentrations of neonicotinoids found in honey overlapped with those that have been found to have significant adverse effects on honeybee health. The dietary risk assessments indicated that the levels of neonicotinoids detected in honey were likely to be safe for human consumption.

The canary in the coalmine; bee declines as an indicator of environmental health.

Bee declines have received much attention of late, but there is considerable debate and confusion as to the extent, significance and causes of declines. In part, this reflects conflation of data for domestic honeybees, numbers of which are largely driven by economic factors, with those for wild bees, many of which have undergone marked range contractions but for the majority of which we have no good data on population size. There is no doubt that bees are subject to numerous pressures in the modern world. The abundance and diversity of flowers has declined along with availability of suitable nest sites, bees are chronically exposed to cocktails of agrochemicals, and they are simultaneously exposed to novel parasites and pathogens accidentally spread by humans. Climate change is likely to exacerbate these problems in the future, particularly for cool- climate specialists such as bumblebees. Stressors do not act in isolation; for example pesticide exposure can impair both detoxification mechanisms and immune responses, rendering bees more susceptible to parasites. It seems certain that chronic exposure to multiple, interacting stressors is driving honeybee colony losses and declines of wild pollinators. Bees have a high profile and so their travails attract attention, but these same stressors undoubtedly bear upon other wild organisms, many of which are not monitored and have few champions. Those wild insects for which we do have population data (notably butterflies and moths) are overwhelmingly also in decline. We argue that bee declines are indicators of pervasive and ongoing environmental damage that is likely to impact broadly on biodiversity and the ecosystem services it provides.

Sensitive determination of mixtures of neonicotinoid and fungicide residues in pollen and single bumblebees using a scaled down QuEChERS method for exposure assessment.

To accurately estimate exposure of bees to pesticides, analytical methods are needed to enable quantification of nanogram/gram (ng/g) levels of contaminants in small samples of pollen or the individual insects. A modified QuEChERS extraction method coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis was tested to quantify residues of 19 commonly used neonicotinoids and fungicides and the synergist, piperonyl butoxide, in 100 mg samples of pollen and in samples of individual bumblebees (Bombus terrestris). Final recoveries ranged from 71 to 102 % for most compounds with a repeatability of below 20 % for both pollen and bumblebee extracts spiked at 5 and 40 ng/g. The method enables the detection of all compounds at sub-ng/g levels in both matrices and the method detection limits (MDL) ranged from 0.01 to 0.84 ng/g in pollen and 0.01 to 0.96 ng/g in individual bumblebees. Using this method, mixtures of neonicotinoids (thiamethoxam, clothianidin, imidacloprid and thiacloprid) and fungicides (carbendazim, spiroxamine, boscalid, tebuconazole, prochloraz, metconazole, fluoxastrobin, pyraclostrobin and trifloxystrobin) were detected in pollens of field bean, strawberry and raspberry at concentrations ranging from MDL, and in some bees, the fungicides carbendazim, boscalid, tebuconazole, flusilazole and metconazole were present at concentrations between 0.80 to 30 ng/g. This new method allows the analysis of mixtures of neonicotinoids and fungicides at trace levels in small quantities of pollen and individual bumblebees and thus will facilitate exposure assessment studies.