Should oral exposure in Hypoaspis aculeifer tests be considered in order to keep them in Tier I test battery for ecological risk assessment of PPPs?

Tiago Natal-da-Luz; Tom Gevaert; Carla Pereira; Daniela Alves; Maria Arena; José Paulo Sousa

doi:10.1016/j.envpol.2018.10.113

Should oral exposure in Hypoaspis aculeifer tests be considered in order to keep them in Tier I test battery for ecological risk assessment of PPPs?

Environ Pollut. 2019 Jan:244:871-876. doi: 10.1016/j.envpol.2018.10.113. Epub 2018 Oct 27.

Authors

Tiago Natal-da-Luz¹, Tom Gevaert², Carla Pereira³, Daniela Alves³, Maria Arena⁴, José Paulo Sousa³

Affiliations

¹ CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Portugal. Electronic address: tiagonluz@iav.uc.pt.
² CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Portugal; Hogeschool Gent, Education, Health and Social Work, University College Ghent, Valentin Vaerwyckweg, Ghent, Belgium.
³ CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Portugal.
⁴ European Food Safety Authority (EFSA), Parma, Italy.

PMID: 30469281
DOI: 10.1016/j.envpol.2018.10.113

Abstract

The laboratory reproduction test with the predatory mite Hypoaspis aculeifer is currently a mandatory test in the new EU data requirements for prospective environmental risk assessment of Plant Protection Products (PPPs). However, the low sensitivity often shown by this mite towards PPPs, when compared to other invertebrates (namely Folsomia candida and Eisenia fetida), makes the test with this species not very useful in the lower tier test battery. However, the current test protocol only considers exposure to contaminants via contaminated soil, disregarding exposure via contaminated food and does not take into account the fact that H. aculeifer is a predatory species. Therefore, through this protocol, the toxicity of contaminants to soil mites might be underestimated and, thus, an adaptation of the test performance, by including exposure via contaminated food, may be necessary. With this aim, two reproduction tests with H. aculeifer were performed using copper chloride as model substance, artificial soil as test substrate and cheese mites as food. The OECD guideline was followed but, while in one test cheese mites from normal laboratory breeding cultures (clean prey mites) were provided, in the other test, cheese mites previously exposed to copper (Cu pre-exposed prey mites) were provided. Predatory mites were affected at lower concentrations in tests using Cu pre-exposed prey compared to test with clean-prey (NOEC = 1225 and 1508 mg kg^-1 and EC₁₀ = 1204 and 1903 mg kg^-1 using Cu pre-exposed and clean prey, respectively). However, this higher sensitivity was not detected by EC₅₀ values (EC₅₀ = 2634 and 2814 mg kg^-1 using Cu pre-exposed and clean prey, respectively). Further tests are needed in order to (i) investigate the relevance of oral exposure to different PPPs, (ii) optimize the contamination of prey mites according to the chemical properties of each substance and (iii) substantiate a proposal to adapt the standard protocol.

Keywords: Contaminated prey; Food ingestion; Predatory mite; Route of exposure; Toxicity.

MeSH terms

Animals
Dose-Response Relationship, Drug
Lethal Dose 50
Mites / drug effects*
Mites / physiology
Models, Theoretical
Reproduction / drug effects
Risk Assessment
Sensitivity and Specificity
Soil / chemistry*
Soil Pollutants / toxicity*
Toxicity Tests / methods*

Substances

Soil
Soil Pollutants