Authors:
Ida Holm Olesen | Region of Southern Denmark | Denmark
PhD Nina Tuxen | Capital Region of Denmark | Denmark
Prof. Poul L. Bjerg | Technical University of Denmark | Denmark
Workshop on groundwater contamination from pesticide point sources
- Knowledge exchange on extent of problem, site investigation, risk assessment and remediation of pesticide contamination arising from point sources
Session organizers: Ida Holm Olesen, Head of section, Region of Southern Denmark, Nina Tuxen, Ph.D, Orbicon, Poul L. Bjerg, Professor, Department of Environmental Engineering, Technical University of Denmark.
Contact person: Ida Holm Olesen, e-mail ida.h.olesen@rsyd.dk, phone 0045 7663 1926.
ACS-theme: 1B. Risk assessment and management
Main idea of the session: Pesticide contamination of groundwater is a common challenge for the European countries. The aim of this session is knowledge exchange and mutual inspiration on the topic of pesticide point sources. Ideally, the session will facilitate forming of new European partnerships on further research and development among authorities, consultants and researchers. The theme session will include the latest research findings on pesticide-point sources.
Background:
In Europe, 70% of drinking water is based on groundwater resources, and in Austria and Denmark drinking water is almost entirely sourced from groundwater. The low value of 0.1 μg/L for individual pesticides as the drinking water standard in Europe implies that water used for production of drinking water has to be of high quality.
Pesticides are among the most widespread contaminants in the European groundwater, and they pose a multifaceted environmental challenge with regard to source identification, investigation, risk assessment and remediation. There are many sources to pesticides in the groundwater, but recent findings in Denmark indicate that between 20 and 45 % of the pesticide findings in the groundwater can be attributed to point sources such as old landfills, plant nurseries, farm yards and sites associated with the preparation and cleaning of pesticide spraying equipment as well as accidental spills.
Pesticide contamination from point sources often consists of a mixture of pesticides ranging from compounds introduced on the market in the 1950ties (e.g. phenoxy acids, triazines) to newer compounds such as isoproturone and bentazone.
The number of potential pesticide-point sources in Denmark is unknown, but a worst case scenario suggests more than 10 to a 100 thousand potential sources with many different pesticides. However, previous experience indicates that only a small number of these sources present a real problem, because the concentrations and contaminant fluxes are low for the majority of sites. In Denmark we are facing the challenge of finding “the needle in the haystack” – identifying the point sources that threaten the groundwater and requires remediation. Danish researchers, authorities and consultants have worked on this for several years, and we have developed a series of innovative tools for data analysis, catchment scale risk assessment and remediation. We believe we are on the right path, but we are very well aware that we have not yet found the recipe for efficient management of pesticide-point sources.
Judged by the limited amount of literature on pesticide point sources available, it seems that other European countries are in a similar situation. Therefore, we suggest this theme session to stimulate knowledge sharing, and identification of approaches for new and improved management of groundwater contamination by pesticides.
Format of session
We suggest a double session of 180 minutes total.
We suggest a workshop where all participants are invited to contribute to knowledge exchange by brief presentations and participation in discussions on key issues. To facilitate this, the programme of the session should contain ample time for discussions in smaller groups as well as plenary discussions. Ideally, the participants should register for the workshop in advance in order to enable preparation of brief presentations and forming of discussion groups before the session starts. If this is not possible, informal presentations will be possible and groups will be formed during the session.
The session can be shaped in cooperation with the AquaConSoil organizers in order to obtain the maximum benefit for all parties involved. If the organizers wish to have a more traditional setup with more platform presentations, we suggest replacing the group discussion with case studies on pesticide-point sources.
We are aware that at least two other Danish abstracts regarding pesticide-point sources have been submitted to the conference. Should they – or other abstracts on the subject - be selected for presentations at the conference, we would be happy – if possible - to integrate them in this session.
Programme: timeframe (minutes), titles of presentations and names of presenters:
5: Introduction to the workshop, Poul L. Bjerg
10: Ice breaker in the groups: The participants introduce themselves to each other
20: Pesticides in the environment –sources, pathways, receptors and environmental challenges, Poul L. Bjerg
10: Challenges related to pesticide point-source contamination of groundwater, Ida Holm Olesen
20: Finding the significant pesticide-point sources – an overview of approaches available, Nina Tuxen
25: Short presentations from other European countries
15: Group discussion
10: Plenary discussion
20: Remediation technologies for pesticide-point sources Katerina Tsitonaki, Orbicon
25: Group discussion – identification of new tools and management approaches and needs for development? (The discussion will be supported by a number of pre-prepared questions)l
20: Plenary discussion and summary of the session, Poul L. Bjerg
Moderator of the session: Poul L. Bjerg