DOI: 10.14466/cefasdatahub.129
title: Microplastics in sediment cores data from the UK continental shelf and slope 2017

description: This dataset contains two CSV files.  One CSV file reports locations and technical details for the cores, along with their slices, subsamples and the number of microplastic particles and fibres recorded in each 5g sample processed.  Details of how the cores were sampled and processed can be found in the publication and its supporting information.
The second CSV file contains x-y data for the micro-ATR-IR analysis of representative particles picked from some of the filters, to provide some numerical data on polymer types and fractions of Nile Red positive particles that could be positively identified as plastics (positives), those that were biological in origin (false positives) and those that could not be confidently identified.  Details of the procedure for this appear below.  Images of the particles along with their IR spectra can be found in the ESI accompanying the publication.
Sediment cores (n=22) used in this study were collected on the RV Cefas Endeavour from 7th to 16th January, and 20th May to 15th June 2017 by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) as a part of integrated monitoring pilot surveys, or Sentinel Monitoring (type-1) cruises (cruise codes CEND01/17 and CEND09/17) (Murray et al, 2017; Eggett, 2018). MP sample collection was opportunistic, carried out alongside the wider survey aims, hence sites were not selected based on MP-driven hypotheses. Cores were collected from three locations; one in the North Sea: DB (n=13), and two sites in the Celtic Sea: NWJB (n=6) and CNYN (n=3).  Site selection at each location was governed by the primary survey monitoring aims, as laid out in the cruise reports (Eggett, 2018; Murray et al., 2017) with all monitoring stations visited cored for MPs on CEND01/17, while a 10% subset of monitoring stations samples for other parameters were cored for MPs on CEND09/17. All locations are designated as Special Areas of Conversation under the Convention for the Protection of the Marine Environment of the North-east Atlantic (OSPAR) and as such are of particular interest for marine policy development or management considerations. Further details of the broader sampling route selection and rationale have been described in Noble-James et al. (2018).

Approximately 50 Nile Red particles were picked off filters from ZnCl2 extracted marine sediment samples. A blue Crimelite (Foster and Freeman) was used to excite the NR fluorescence and the filters were viewed through orange safety spectacles, allowing the fluorescing particles to be detected.  A bamboo cocktail stick moistened with ethanol was used to assist with removal. The particles were placed on a 25 mm diameter 0.45µm porosity silver filter (Merck Millipore), taped by its edges to a mounting plate for the Bruker Hyperion 2000 microscope (single cooled MCT detector, coupled with a Vertex 70 FT-IR).  Particles were located one by one, photographed using the 4X visible lens for size and shape information, then measured using the 20X Ge tip ATR lens (32 scans, 4cm-1 resolution, pressure setting “1”).  Spectra were assessed visually, for general acceptability, then polymer identification was verified based on the % match against provided polymer libraries (ATR-FTIR-Library complete, Vol.1-4; Bruker Optics ATR-Polymer Library; IR-Spectra of Polymers, Diamond -ATR, IR-Spectra of Polymers, Geranium-AT & IR-Spectra of Additives, Diamond-ATR). Only matches above 60% were selected for a positive microplastic validation and polymer identification (Leistenschneider et al., 2021).  No spectral corrections (baseline flattening, ATR correction, moisture/CO2 removal) were applied. If these tools were used the HQI values will increase, but at the cost of increased time input.  We chose not to do this to simplify the operational workflow.
Eggett, A., McBreen, F., Griffiths, Y., van Rein, H., Last, E. & Callaway, A, 2018. Report no 21. CEND0917 Cruise Report: North-West of Jones Bank and The Canyons Marine Conservation Zones’ Monitoring Survey.
Leistenschneider C., Burkhardt-Holm P., Mani T., Primpke S., Taubner H. & Gerdts, G. 2021 Microplastics in the Weddell Sea (Antarctica): A Forensic Approach for Discrimination between Environmental and Vessel-Induced Microplastics.
Murray, J., Holmes, I., Silburn, B., Sivyer, D., Pettigrew, J., S., S. and Ware, S., 2017. Survey Report: CEND 01/17 Ecosystem Based Monitoring Case Study Southern North Sea: Dogger Bank Strata 2017.
Noble-James, T., Jesus, A. & McBreen, F., 2017. Monitoring guidance for marine benthic habitats. In: J.R.N. 598 (Editor), Peterborough.