The molecular basis of simple relationships between exposure concentration and toxic effects with time

Tennekes, Henk; Sánchez‐Bayo, Francisco

doi:10.1016/j.tox.2013.04.007

Cited by 94 publications

(69 citation statements)

References 97 publications

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“…The neuronal death toll accumulates as more and more pesticide molecules bind to other nAChRs until the organism cannot cope with the damage and dies. The main difference between this mode of action and that of other pesticides is that effects are cumulative with time, because neurons do not regenerate-it has been termed time-cumulative or reinforced toxicity (Tennekes and Sánchez-Bayo 2013). This mechanism certainly applies to all arthropods tested to date, but not to birds.…”

Section: The Delayed Mortality and Chronic Toxicity Of Neonicotinoidsmentioning

confidence: 99%

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

Pisa

Goulson

Yang

et al. 2017

Environ Sci Pollut Res

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144

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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 .

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Section: The Delayed Mortality and Chronic Toxicity Of Neonicotinoidsmentioning

confidence: 99%

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

Pisa

Goulson

Yang

et al. 2017

Environ Sci Pollut Res

Self Cite

201

144

View full text Add to dashboard Cite

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“…Delayed mortality, also called time-cumulative toxicity or reinforced toxicity, results in increased mortality rates with time of exposure and it applies to toxicants that act irreversibly or slowly reversibly on a receptor while producing an irreversible effect [63]. It can be detected by estimating the acute/chronic ratios of a toxic substance, which in this case may span two or three orders of magnitude [64], but the best way to assess it is by conducting time-to-event (TTE) toxicity tests.…”

Section: Toxicity Assessmentmentioning

confidence: 99%

“…If the cell cannot be regenerated (i.e. neurons), such an effect is irreversible, hence the resulting pattern of toxicity is not only dependent on dose but also on the time of exposure to sublethal levels [63]. For such chemicals, the risk assessment should aim at determining the time to 50% mortality (T50) in a population under the normal and worst exposure scenarios, as it has been described elsewhere [28].…”

Section: Risk Assessmentmentioning

confidence: 99%

Assessment of ecological risks of agrochemicals requires a new framework.

Bayo¹,

Tennekes²

2017

Environ Risk Assess Remediat

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The widespread contamination of a significant proportion of the planet's land and water with pesticides is undeniable. While this takes place, innumerable species of animals associated with agricultural landscapes are declining at rates that may put them on the brink to extinction in the span of a lifetime. It is evident, therefore, that our current risk assessment of agrochemicals has failed to protect the environment. A new framework is proposed here that combines the mandatory introduction of new toxicity endpoints with a more logical assessment of risks within the existing tiered approach. Chronic toxicity tests designed to detect time-cumulative effects should be a requirement for assessing delayed mortality as well as population endpoints that are crucial for the recovery and survival of species, such as fecundity. Exposure assessments should ensure that field monitoring data integrate both the highest and average levels of residues, as the former levels determine the main ecological impacts. The first tier of the risk assessment should comprise an evaluation of short-term mortality (as currently done by a hazard quotient on acute toxicity) and of the lethality after chronic exposure to sublethal levels. Chemicals that pass this tier should be assessed in a second tier whereby the crucial population endpoints are evaluated. Unless there is evidence of recovery with no negative effects on reproduction of the species tested, a chemical should not be registered. Further tiers of assessment, including sublethal effects, community effects tested in model ecosystems (i.e. microcosms, mesocoms) and field trials can still be used as supporting evidence, as it is currently done. AbstractAssessment of ecological risks of agrochemicals requires a new framework.

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“…It is a relatively new pesticide (patent 1985) 1 , which is a disruptor of the nervous system by acting as an inhibitor at nicotinic acetylcholine receptors found in many insects 2 . The possible relationship between neonicotinoid pesticides and massive disappearance of honeybees from the hive is a topic of great interest nowadays [3][4] .…”

Section: Introductionmentioning

confidence: 99%