Groundwater ecotoxicology - a critical review on exposure and effects

Abstract

Europe's vital groundwater resources face a growing threat from emerging organic contaminants (EOCs) and persistent, mobile, and toxic (PMT/vPvMs) chemicals. These pollutants, often unregulated and inadequately removed during wastewater treatment, persist in the environment for extended periods. This thesis examines the current understanding of EOCs and PMT/vPvMs in European groundwater, their potential risks to human health and ecosystems, and identifies critical knowledge gaps. The study analyzes data from 30 studies across 17 European countries, revealing a diverse range of EOCs, including pharmaceuticals (e.g., Carbamazepine), pesticides, and industrial chemicals (e.g., bisphenol). This analysis identified concemingly high maximum concentrations of various EOCs in specific regions: Carbamazepine (100-900 ng/L in Germany, 245-3600 ng/L in UK). PFOA (530-29889 ng/L in Alessandria. Italy), and bisphenol (9300 ng/L in UK, 4166-11985 ng/L in France). Notably, data from Sweden in 2011 highlighted the presence of DEET (60 ng/L) and N-Butylbenzenesulfonamide (108.24 ng/L), indicating potential broader contamination. Risk Quotients (RQ) for Diclofenac and Nonylphenol indicate potential ecological risks in groundwater, particularly for Daphnia magna, while Carbamazepine poses a lower risk. A critical knowledge gap exists regarding the long-term health effects of EOCs, especially at the low concentrations frequently detected in groundwater. While their persistence and mobility raise concern for both aquatic life and human health, the full impact remains unclear. Additionally, current monitoring methods may not capture the complete spectrum of EOCs present, underlining the need for improved detection strategies. This thesis emphasizes a multifaceted approach to safeguard Europe's groundwater. Stricter regulations are crucial to control EOCs at the source. Improved monitoring programs are essential to track pollution levels and identify hotspots. Furthermore, research is needed to understand the fate and transport of these contaminants within groundwater systems, informing the development of effective mitigation strategies. Existing EU regulations offer a starting point for groundwater protection but need updates for emerging threats like EOCs. The European Groundwater Watch List is a positive step, but a more robust framework is crucial. International cooperation, like the UNECE Water Convention, is vital for managing shared resources. This thesis highlights the urgency to address EOCs by advocating for further research, improved monitoring, and stricter regulations to safeguard Europe's vital groundwater for future generations.