Applying Organic Compounds as Indicators in Innovative Monitoring Strategies
by Wiebke Warner
Date of Examination:2019-07-08
Date of issue:2019-08-07
Advisor:Prof. Dr. Tobias Licha
Referee:Prof. Dr. Matthias Willbold
Referee:Dr. Karsten Nödler
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Abstract
English
Today, demands on water quality are diverse and strongly differ by water use related criteria. Additionally, the complex topic of water quality is of increasing importance for citizens and is therefore often emotionally loaded by media. Surface waters are important ecosystems for biota. Additionally, they can serve as drinking water resources and have become increasingly important for recreational activities and tourism. Ground and surface waters hence deserve protection, which creates a need for reliable water quality monitoring that produces high resolution and information-rich water quality data. Currently, European water quality is assessed under the water framework directive (WFD), which has shown that water quality needs to be improved in many catchments. Nowadays, water quality data are based on fixed stations with monitoring conducted on predetermined dates and focusing on a more historically relevant list of classic water quality indicators. This often generates a biased and insufficient picture of the water quality. Understanding system dynamics to meet the needs of divers demands on water quality between catchments and water bodies requires a more flexible approach, while producing more meaningful data. Classic water quality indicators, such as inorganic ions, are often not source specific and too general as they have myriad different anthropogenic and natural origins. They are only to a minor extent suitable for reliable source apportionment, to understand system dynamics and risk assessment. In contrast, sources of micropollutants such as pharmaceuticals, lifestyle and personal care products, pesticides, household chemicals etc., are strongly related to anthropogenic activities. These in turn are very source specific, bear neglectable natural background concentrations, and hence can act as powerful, reliable and unbiased indicators. This thesis gives a comprehensive and systematic overview of (micro)pollutants used as indicators in the aquatic environment over the last decades. Successfully exploiting micropollutants as indictors starts with appropriate sampling procedures, sample storage and analysis. These are essential steps in providing reliable data. This review is structured into the qualitative, semi-quantitative and quantitative use of indicators and presents a guide on how to decide for a suitable set of indicators. Besides suitable sets of indicators, a water quality monitoring strategy, adjusted to the catchment needs and producing reliable and information-rich data, is important for water quality assessment. Even though micropollutants are powerful indicators, they require analysis in a laboratory environment and do not allow acquisition in real-time. Correlating micropollutants which indicate a water quality threat to a universal signal (proxy), e.g. electrical conductivity, enables real-time data. Proxy mapping permits detecting potential pollution hot spots with a high information density for consecutive sampling. These signals can be derived from cheap sensor arrays in real-time which can easily be installed on automated sampling boats or drones. The successful application of this innovative strategy is presented on the inflow of a small tributary into Lake Garda (Italy) with an EC anomaly. Besides recent applications, micropollutants can also serve to reconstruct historic pollution when they are stored in environmental archives such as sediment cores. This transfer is presented by two age-dated sediment cores of Lake Süßer See (Mansfeld area, Germany) historically a region of high intensity copper shale mining. Released during combustion, polycyclic aromatic hydrocarbons (PAHs), and especially the ratios of them, allowed delineating aqueous particle-bond trans- port of PAHs into the lake from atmospheric deposition. Furthermore, an outlook for possible changes and new possibilities in water quality monitoring is presented. Future water quality problems regarding highly polar persistent mobile organic compounds (PMOCs) breaking the barrier into drinking water and indicators for pristine non-anthropogenic influenced areas are discussed in the conclusions of this thesis.
Keywords: micropollutants; water framework directive; innovative monitoring strategies; indicators