Why apex predators?
Apex predators are particularly well suited to contaminant monitoring as they are at the top of food webs and thereby are important for the understanding of exposures to the wider environment as well as to humans. Together with chemical data of prey species such as fish, chemical data of apex predators provide valuable information on potential biomagnification of persistent and bioaccumulative chemicals in marine, freshwater and terrestrial food webs. The analysis of apex predators and prey is organised in three tiers:
Tier 1: screening exercise
First set of samples consisting of livers from common buzzard, Eurasian otter, harbour seal and filets from freshwater and coastal fish are retrieved from Environmental Specimen Banks, scientific collections and Natural History Museums in Germany, the Netherlands, Sweden and United Kingdom.
Tier 2: temporal trend analysis
Retrospective trend analysis (2000-2018) for freshwater fish, otter and buzzard.
Tier 3: replication and transfer
Additional apex predator samples, which will be retrieved from Environmental Specimen Banks, scientific collections and Natural History Museums from all over Europe.
Analysed substances and analytical methods
The project will make use of state-of-the-art analytics (e.g. non-target, wide-scope target and suspect screening) that allow for screening of several thousands of chemicals in each sample and prioritization of frequently occurring pollutants and their mixtures. In every sample more than, 2,400 contaminants (e.g. pharmaceuticals, pesticides, biocides, perfluorinated compounds, industrial chemicals) will be analysed by wide-scope target analysis. Additionally, a battery of small-scope target techniques will be used to analyse dioxins and dioxin-like compounds; chlorinated alkanes (C10-13; C14-17), novel organophosporous flame retardants, Mercury, Declorane Plus, PCBs, OCPs, PBDEs and Hexabromocyclododecane. All samples will be subjected also to non-target screening allowing for identification (confirmation of identity) of unknowns from mass spectral libraries. Furthermore, we would screen each sample for presence/absence of 40,000+ substances listed in the NORMAN Database System – Substance Data-base (https://www.norman-network.com/nds/susdat/). The substances would be prioritised based on their frequency of appearance and persistent, bioaccumulative or toxic (PBT) properties. These 40.000+ substances will also be semi-quantified (if found) based on the substance structure similarity algorithm (https://www.norman-network.com/nds/SLE/). Any sample will stored following the NORMAN protocols and can be screened retrospectively for any substance or its transformation product which might pop up in future (digital sample freezing).
Prioritisation of substances according to their PBT properties.
For this purpose, substances in the NORMAN database are screened using JANUS (https://www.vegahub.eu/portfolio-item/janus/). This tool uses in silico approaches as well as experimental data from freely available databases to evaluate properties of concern such as PBT. Since this procedure can provide an automated and relatively quick assessment of PBT properties, the entire list of substances in the NORMAN database (40,000+ chemicals), which is also used for non-target screening, is screened for PBT candidates and prioritized accordingly. At the same time the data with the findings in biota will be prioritized according to the detection rate.
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