The environmental risks of neonicotinoid pesticides: a review of the evidence post 2013

Abstract

Neonicotinoid pesticides were first introduced in the mid-1990s, and since then, their use has grown rapidly. They are now the most widely used class of insecticides in the world, with the majority of applications coming from seed dressings. Neonicotinoids are water-soluble, and so can be taken up by a developing plant and can be found inside vascular tissues and foliage, providing protection against herbivorous insects. However, only approximately 5% of the neonicotinoid active ingredient is taken up by crop plants and most instead disperses into the wider environment. Since the mid-2000s, several studies raised concerns that neonicotinoids may be having a negative effect on non-target organisms, in particular on honeybees and bumblebees. In response to these studies, the European Food Safety Authority (EFSA) was commissioned to produce risk assessments for the use of clothianidin, imidacloprid and thiamethoxam and their impact on bees. These risk assessments concluded that the use of these compounds on certain flowering crops poses a high risk to bees. On the basis of these findings, the European Union adopted a partial ban on these substances in May 2013. The purpose of the present paper is to collate and summarise scientific evidence published since 2013 that investigates the impact of neonicotinoids on non-target organisms. Whilst much of the recent work has focused on the impact of neonicotinoids on bees, a growing body of evidence demonstrates that persistent, low levels of neonicotinoids can have negative impacts on a wide range of free-living organisms.

Method validation and simultaneous quantification of eight organochlorines/organophosphates in apple by gas chromatography

“…Since human health has been a matter of primary concern so many studies which have so far been done arrived at the conclusion that pesticide exposure is associated with chronic health ailments . These primarily include dermatologic, respiratory, memory disorders like neurodeficits, birth defects and miscarriages . Moreover, bioaccumulation of pesticide residues show an association to cause cancer, depression, seizure disorder, liver and kidney dysfunction .…”

Foraging bumblebees acquire a preference for neonicotinoid-treated food with prolonged exposure

“…When directly applied to crops (typically as a seed treatment) or as contamination of wildflowers, this can result in low-level contamination of nectar and pollen at concentrations in the parts per billion (ppb), providing a direct route of exposure to foraging bees [6,18]. An increasing number of studies investigating the effects of neonicotinoid exposure on bees have reported detrimental impacts on a range of behaviours [19–21], including individual foraging performance, which could impair colony development in social bees [22,23].…”

Toxicity of Agrochemicals Among Larval Painted Lady Butterflies (Vanessa cardui)

“…No clear dose response was evident from these results; 7 µg/g produced no significant effects, and 8 µg/g did not significantly alter eclosion or butterfly mass. By comparison, in Wood and Goulson () the highest concentration of clothianidin was detected in maize pollen that was previously treated with neonicotinoids (36.88 ng/g), yet only 4 ng/g was detected on nontreated wildflowers occurring along roadside ditches near feed yards in the Southern High Plains (Peterson et al ). Reported 24‐h median lethal concentration values for clothianidin ranged from 2400 to 186 000 ng/g among 3 agricultural crop pest moths (Botías et al ; Wood and Goulson ).…”

“…By comparison, in Wood and Goulson () the highest concentration of clothianidin was detected in maize pollen that was previously treated with neonicotinoids (36.88 ng/g), yet only 4 ng/g was detected on nontreated wildflowers occurring along roadside ditches near feed yards in the Southern High Plains (Peterson et al ). Reported 24‐h median lethal concentration values for clothianidin ranged from 2400 to 186 000 ng/g among 3 agricultural crop pest moths (Botías et al ; Wood and Goulson ). However, crop pest species may not be reliable indicators of clothianidin toxicity among pollinators because multiple generations have been exposed to pesticides, possibly eliciting resistance (Wood and Goulson ).…”

“…Clothianidin toxicity within the order Lepidoptera varies considerably (Wood and Goulson ). In the present study clothianidin did not induce effects in V. cardui larvae up to 5 µg/g (slower developmental times and lowered mass on emergence as butterflies), and an LD50 could not be calculated.…”