Mass Fluxes of Xenobiotics Below Cities: Challenges in Urban Hydrogeology
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Eawag_06612 Environ Earth Sci (2011) 64:607–617 DOI 10.1007/s12665-010-0880-0 ORIGINAL ARTICLE Mass fluxes of xenobiotics below cities: challenges in urban hydrogeology Mario Schirmer • Frido Reinstorf • Sebastian Leschik • Andreas Musolff • Ronald Krieg • Gerhard Strauch • John W. Molson • Marion Martienssen • Kristin Schirmer Received: 7 June 2010 / Accepted: 16 November 2010 / Published online: 4 December 2010 Ó Springer-Verlag 2010 Abstract Urban areas are the focus of major ecological, human activities on urban water systems and on processes social and economical activity. They are thus also prime within the urban watershed. The use of indicator sub- locations of increasing conflict with regard to water use and stances, representing different contaminant sources and water protection. As a direct and/or indirect consequence of pathways, integral pumping tests and mass balance urban land use and human activity, urban water systems are approaches are suitable alternatives within these environ- frequently polluted with organic contaminants including ments. The issues are explored using contaminant mass waste water-born xenobiotics such as pharmaceuticals, balance examples from Halle/Saale and Leipzig, Germany. personal care products (collectively known as PPCPs) and endocrine-active substances. This study reviews new inte- Keywords Leaky sewers Á Mass balance Á grated methodologies including flux calculations as well as Micropollutants Á PPCP Á Urban groundwater Á Urban chemical investigations for determining the impact of hydrogeology M. Schirmer (&) R. Krieg Department of Water Resources and Drinking Water, Eawag, Department of Hydrogeology, UFZ, Swiss Federal Institute of Aquatic Science and Technology, Helmholtz Centre for Environmental Research, Ueberlandstr. 133, 8600 Duebendorf, Switzerland Theodor-Lieser-Str. 4, 06120 Halle/Saale, Germany e-mail: [email protected] e-mail: [email protected] F. Reinstorf J. W. Molson Department of Water and Waste Management, Department of Geology and Geological Engineering, University of Applied Sciences Magdeburg-Stendal, Laval University, Quebec City, Quebec G1V0A6, Canada Breitscheidstr. 2, 39114 Magdeburg, Germany e-mail: [email protected] e-mail: [email protected] M. Martienssen S. Leschik Chair Biotechnology of Water Treatment, Department of Groundwater Remediation, UFZ, Institute for Environmental Technology, Helmholtz Centre for Environmental Research, Brandenburg University of Technology Cottbus, Permoserstr. 15, 04318 Leipzig, Germany Siemens-Halske-Ring 8, 03046 Cottbus, Germany e-mail: [email protected] e-mail: [email protected] A. Musolff Á G. Strauch K. Schirmer Department of Hydrogeology, UFZ, Department of Environmental Toxicology, Eawag, Helmholtz Centre for Environmental Research, Swiss Federal Institute of Aquatic Science and Technology, Permoserstr. 15, 04318 Leipzig, Germany Ueberlandstr. 133, 8600 Duebendorf, Switzerland e-mail: [email protected] e-mail: [email protected] G. Strauch e-mail: [email protected] 123 608 Environ Earth Sci (2011) 64:607–617 Introduction Within the perspective of xenobiotic risk assessment, we also need to provide xenobiotic exposure scenarios for the Half of the world’s population and about 73% of Euro- urban receiving water resources. This approach should peans live in cities. In addition, about 82% of global incorporate sound knowledge on both the xenobiotic con- population growth currently occurs in cities of the centration variability as well as on the xenobiotic mass developing countries (UN 2004). Consumption of land by fluxes in urban watersheds. While concentration variability increasing urban sprawl and associated anthropogenic in time and space provides valuable information for toxi- activity is seriously degrading urban water quality and cological assessments of the receiving ecosystems, mass quantity. In particular, the pollution of urban water sys- flux estimations allow the assessment of long-term trends tems by diffusive and direct contribution from waste and can be more useful for relating total impact loading water sources is of growing concern (Schwarzenbach with respect to the city’s size, the number of inhabitants et al. 2006). In this regard, an integral view on urban and the density and condition of the sewer network. water resources is needed since both surface water and The goal of this paper is to (1) summarize the unique groundwater resources are affected by waste water input. characteristics (relevant to xenobiotic measurements) For example, urban surface water may be degraded by which exist in urban hydrogeological settings, (2) identify effluent discharge from waste water treatment plants or by which indicators can be used to assess PPCP contamination combined sewer overflows (CSOs). Groundwater may be and (3) to determine which investigation and monitoring deteriorated by waste water losses from leaky sewers. The techniques can be used. pollution of groundwater resources is of special concern The unique conditions within urban watersheds require since xenobiotics can persist over several decades, leading new methodologies for assessing the impact of human to sustained contamination. The challenge in assessing the activities and to identify the relevant physical processes. contamination of urban water resources lies in interpreting To this end, we have used different approaches in relation the complex spatial–temporal interaction of groundwater to the hydrogeological and hydrodynamic environment of and surface water with the sewage system and the the cities of Leipzig and Halle/Saale (Germany). For the resulting heterogeneity of xenobiotic loads and concen- urban area of Halle, a flow and transport model was trations (Musolff 2009). developed based on the interaction between surface water Our past research on urban water supplies in Leipzig and of the Saale River and groundwater. In the city of Leipzig, Halle/Saale (Germany) focused on the source, distribution we established a monitoring program that allowed detailed and transport behaviour of xenobiotics as indicator targets studies on the distribution of xenobiotics and their path- for assessing the anthropogenic impact on the urban water ways between waste water, surface water and groundwater. system (Strauch et al. 2008). The xenobiotics considered in Multivariate statistics and integral pumping tests (IPTs) that study were micropollutants including pharmaceuticals, were applied to account for the highly heterogeneous personal care products (collectively referred to as PPCPs) conditions and time-varying concentrations. At both sites, and industrial chemicals, which show low concentrations in we demonstrated the use of indicator targets consisting of urban waters and are a direct and/or indirect consequence inorganic major ions, isotopes and compound-specific of human activity (Schirmer and Schirmer 2008). An patterns of xenobiotics. increasing number of PPCPs are being found in urban water systems and drinking water (e.g., Ternes 1998; He- berer 2002). Since the number of prescriptions generally Unique hydrogeological characteristics in urban areas rises with increasing age and as people are living longer, it can be assumed that we will face an increasing input of Subsurface environment pharmaceuticals into the urban water cycle. With regard to toxicological effects, several studies have Heterogeneous geology, ground surface sealing and already shown that as yet unknown eco-toxicological extensive subsurface infrastructure are common charac- impacts due to the presence of PPCPs may exist (Luc- teristics of many urban areas (Lerner, 2002). As a conse- kenbach and Epel 2005; Schmitt-Jansen et al. 2007). The quence, surface water and groundwater water quality and potential long-term effects of such compounds in the eco- quantity as well as groundwater recharge can be affected. system and in humans, as well as their fate in the envi- For example, building structures, electrical, transportation ronment, are also widely unknown (Schwarzenbach et al. and communication systems and complex water supply and 2006). Thus, an emerging field of scientific and engineer- sewer networks, often extend into the groundwater zone. ing research is focussing on the safe disposal of increasing Via such complex pathways, contaminants can be intro- amounts of waste water without endangering ecosystems duced from shallow or ground surface sources into the and future water usage. subsurface and further into the groundwater. Primary 123 Environ Earth Sci (2011) 64:607–617 609 sources of contamination are from chemically active variable contamination of urban areas are, to date, still building materials and from leaks in the sewer system. widely lacking (Schirmer et al. 2007). Contamination through diffuse and point sources Materials and methods The introduction of urban contaminants into the aquatic environment occurs mainly through waste water, with Indicator substances each source being of variable composition. Most con- taminants originate as effluent from the waste water A large variety of parameters are related to anthropogeni- treatment plants which can be treated as essentially point cally induced activities in urban areas. We have selected source discharges into rivers. A significant proportion of suitable indicators for studying the sources, transport and waste water input also originates from leakage of waste distribution, and the transfer processes of water-bound water systems (5–20% of the waste water dry