Author: uset

3C - Channel Catchments Cluster

3C - Channel Catchments Cluster

The mining of underexploited databases:
A relevant tool to monitor the sediment
contamination with trace elements

J. Richir*, J.M. Pini, S. White, G.J. Watson (* jonathan.richir@port.ac.uk)
Institute of Marine Sciences, School of Biological Sciences,
University of Portsmouth, Ferry Road, Portsmouth, PO4 9LY, UK

Introduction
At the European level, the two main legislations developed to protect and restore the chemical quality of aquatic meadows are the Water Framework Directive (WFD; EC, 2000) and the Marine Strategy Framework Directive (MSFD; EC, 2008). They respectively aim to achieve “Good Ecological Status” for all European water bodies, by 2015, and “Good Environmental Status” for all seas, by 2020 (Legorburu et al., 2013 - Estuar Coast Shelf S). Among the variety of contaminants that threaten estuarine and coastal environments, trace elements (TEs; Fig. 1) remain of major concern because of their toxicity, their ability to highly concentrate in biota and persistence in sediments. Large spatiotemporal surveys are thus performed to monitor their environmental occurrence. But the resulting databases generated, that represent an important source of information readily available to environmental scientists, remain however often underexploited.

UK databases
There are two main public sources in UK from which data on environnemental contaminants can be freely acquired :
The Environment Agency (EA) DataShare (www.geostore.com/environment-agency/), that holds several categories of environmental databases made available by the Department for Environment, Food & Rural Affairs (Defra) and its agencies, among which data on environmental contaminants.
The Marine Environment Monitoring and Assessment National (MERMAN) database, managed by the British Oceanographic Data Centre (BODC; www.bodc.ac.uk/projects/uk/merman/), that holds data collected under the Clean Safe Seas Environmental Monitoring Programme (CSEMP).
Together, they cover the complete range of water bodies, from inland freshwaters to transitional, estuarine waters to coastal waters for the EA database, and from coastal to open sea waters (little estuarine data) for the MERMAN database.

Fig. 1 - Essential and non-essential elements, abundant or in traces (modified after Amiard,, 2011)

Objectives
In this study, we investigate the long term trends of sediment contamination along the coasts of South England over a 30 year period of time, using the existing TE databases of the EA and the BODC. We also aim to point out the drivers for the changes seen and to predict what mitigations can be expected in the coming years, and when the achievement of the European objectives will be completed.

a

Data mining
Based on a detailed list of “Determinands” furnished by the EA and the BODC, we requested data on sediment TE levels for the South of England. Regarding the request toward the EA, we further had to determine the “Sample Point Types” we were interested in.
The sediment contamination datasets furnished by the BODC, dedicated to marine waters, did not require any further filtering. The datasets furnished by the EA, grouped by region and concerning inland and marine environments, had to be first projected on Google Earth, and only sites in transitional, estuarine and coastal waters monitored for TEs were further considered.

b

c

Data analysis
The exploitation step of the new resulting dataset is relevant since “all competent authorities undertaking monitoring use the (same) programmes' monitoring manual, the Green Book” (www.cefas.defra.gov.uk/). The statistical, graphical and mapping analysis of sites monitored for TEs will give, once completed, an overview of the spatiotemporal evolution of the sediment contamination at different scales, from global to regional to local (Fig. 2). It will also predict the future evolutionary trends of the sediment contamination and will allow to better target the future monitoring efforts.

Acknowledgements
Authors are grateful to the EA and the BODC. This work was performed in the framework of the Channel Catchments Cluster (3C) programme, funded by the European Regional Development Fund.

POSITIVES
data freely available;
large spatiotemporal coverage;
common monitoring techniques (Green Book);
collaborative tool between environment actors.

NEGATIVES
relies on existing monitoring programmes and databases;
time consuming;
requires specific scientific skills: analytical chemistry, GIS-mapping, statistics.

Fig. 2 - a) GIS-mapping of the sites monitored for TE sediment contamination along the coasts of south England, and b) regional and c) local zooms in the Fall Estuary area.

Conclusion and perspectives
The mining of sediment contamination databases available from public sources is a powerful tool to assess the contamination of the environment in the framework of European directives. Since it requests specific scientific skills, it can aslo be seen as an opportunity for close collaboration between scientists, environment managers and policy makers.