EnvFate · Study of the environmental impact of insecticides by metabolomic foot-printing approach

Study of the environmental impact of insecticides by metabolomic foot-printing approach

"Introduction: Mosquitoes can carry infectious diseases from person to person and from place to place. Presence and establishment of invasive mosquito species such as Aedes aegypti and Aedes albopictus are rapidly increasing in the European environment. Mostly due to the increase of international exchanges (rapid movement of people infected with the virus and competent mosquito vectors), urbanisation (high density of susceptible people, a plethora of mosquito breeding sites), and the global warming (eg, the capacity of mosquitoes to transmit the virus is heavily dependent on temperature). Indeed, the presence of mosquito vectors can create a risk of an epidemic such as dengue, chikungunya or more recently the Zika virus. Sustainable vector management is the only means that effectively could prevent and control the transmission of the viruses of public health importance. State-of-the-art: Since the appearance of the European Directive (98/8/CE) in 1998 concerning the marketing authorizations of biocides, the use of the synthetic insecticides has reconsidered. Indeed, it forbids, since September 2006, the use of non-approved synthetic products. Therefore, this Directive led to the increasing use of biological insecticides such as toxins (cry proteins) produced by the bacterium Bacillus thuringiensis israelensis (Bti) that kills mosquito larvae upon ingestion. Thus higher mosquito population leads to higher use of Bti that ultimately builds anthropogenic burden in the southernmost part of Europe. Objectives and overview of the action: Being a natural product, Bti producing insecticidal Cry proteins has largely assumed as ""Environment-friendly"" and that it does not have any negative influence on the environment. Does Bti is so harmless? To our knowledge, the environmental fate and impact of this biological substance are poorly studied and this is the objective of the proposed project. This study is important at the environmental level as the presence of emerging pollutants in the different environments is nowadays one of the major concerns and is of critical importance to regulatory authorities. Although Bti is not yet identified as an emerging pollutant, environmental protection associations have already pointed out the overuse of this biocide for invasive mosquito population control. Besides studying Bti, we also examined one chemical insecticide for comparison. We chose α-cypermethrin as it is still a lot used as an insecticide in the rice field treatments. Environmental Metabolomic Footprinting (EMF) approach: EMF consists of the metabolomic data acquisition (through LC-MS) and data processing via the use of multivariate statistical analysis. We employed EMF to know the impact of both insecticides on the sediment, their resilience time, and on longer-term evidence the potential pollution biomarkers (overexpression of sediment endogenous compounds, transformation products,…). In parallel to the metabolomic analysis, a study on the presence of a mixed microbial community in the test sediments is underway using a metabarcoding approach. The metabarcoding analysis will allow evaluating the microbial community responses to the Bti and therefore to evaluate its eco-toxicity. The use of omics approaches (metabarcoding and metabolomics) applied to the sediment matrix is an innovative ecotoxicology assessment tool. It has the potential to allow the identification of potential Bti associated biomarkers. Conclusions: The conclusions of the action cannot be yet described completely as some aspects are still under evaluation. Our findings from metabolomics data suggest that the EMF approach offers to monitor changes in the meta-metabolome of the sediment after Bti and α-cypermethrin treatment. It also provides a time-dependent metabolic profile of contaminated sediment samples to evaluate the resilience time of the sediment."

Data: CORDIS, © European Union