Advancing the environmental risk assessment of non‐target arthropods for plant protection products by accounting for the impact on ecosystem services and on the ecological function. Experimental work on exposure
Year: 2026
Type: article
Abstract: This report presents the chemical residue measurements of a series of exposure studies with non‐target arthropods (NTA). Two NTA species, Mamestra brassicae (moth larvae) and Coccinella septempunctata (ladybird larvae and adults tested separately), have been exposed via different routes to four formulated plant protection products (PPP) and were sampled at intervals during 6 days. Two strongly sorptive herbicides were combined in mixture A: diflufenican (DFF, non‐volatile), and prosulfocarb (PSC, volatile), and two weakly sorptive active ingredients in mixture B: the herbicide metamitron (MMT, non volatile) and the fungicide metalaxyl‐M (MLX, volatile). For each mixture, a single spray dose was applied using a Potter tower spray system to expose NTA either via (i) direct insect overspray, (ii) a dried residue on natural substrate surface (leaf or soil), (iii) dietary intake of oversprayed food items. Filter discs sampled during the spray events were used to derive actual spray deposits. Overspray residues in the three types of NTA species were evaluated by fitting the decreasing pesticide amount on the insect exterior surface with a two‐phase disappearance curve. Chemical analysis successfully monitored residues in all samples, except some longer time points after overspray where residues dropped <LOQ. Within 24h, for nearly all combinations of test species/chemicals, exterior residues had declined by ≥80%, except for MMT in ladybird larva (42% decline). The volatile chemicals showed faster loss from the insect exterior than the non‐volatile chemicals. The non‐volatile chemicals absorbed more rapidly in the ladybird adults than in the two softer bodied larval species, despite the adult beetles’ hard carapace exterior. Insect residues rapidly increased for the other exposure routes. For the first few hours, total insect residues resulting from direct overspray were highest of all exposure routes measured throughout the 6‐day testing period. With overspray residues rapidly declining within the course of the first day, dietary exposure became the dominant exposure route for both larval test species for most timepoints sampled ≥24 h, except for overspray still dominating MMT residues in ladybird larvae. Ladybird adults showed the highest residues from leaf contact exposure ≥1 day for DFF, PSC and MLX, while soil contact exposure resulted in the highest residues of MMT. For all studies and chemicals, insect residues (in mg a.i./kg) are expressed as Residue Unit Doses (RUD) by normalizing to a spray dose rate of 1 kg a.i./ha. The time profile for RUD in exposure studies allows for comparison between chemicals, between test species applied with different dose, and with insects collected in field studies. For all combinations of test species/chemicals, various exposure routes resulted in RUD values in the period of 1‐6 days after spraying that were above the 90‐percentile RUD values measured for a variety of active ingredients in pooled insect samples collected in field studies. © European Food Safety Authority, 2024
Source: EFSA Supporting Publications
Institutions: Wageningen University & Research, University of Coimbra
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W7203765499