Bestimmung von Umweltqualitätsnormen für potenziell gewässerrelevante Stoffe

A national survey of trace organic contaminants in Australian rivers

Trace organic contaminant (TrOC) studies in Australia have, to date, focused on wastewater effluents, leaving a knowledge gap of their occurrence and risk in freshwater environments. This study measured 42 TrOCs including industrial compounds, pesticides, and pharmaceuticals and personal care products by liquid chromatography tandem mass spectrometry at 73 river sites across Australia quarterly for 1 yr. Trace organic contaminants were found in 92% of samples, with a median of three compounds detected per sample (maximum 18). The five most commonly detected TrOCs were the pharmaceuticals salicylic acid (82%, maximum = 1530 ng/L), paracetamol (also known as acetaminophen; 45%, maximum = 7150 ng/L), and carbamazepine (27%, maximum = 682 ng/L), caffeine (65%, maximum = 3770 ng/L), and the flame retardant (2-chloroethyl) phosphate (44%, maximum = 184 ng/L). Pesticides were detected in 28% of the samples. To determine the risk posed by the detected TrOCs to the aquatic environment, hazard quotients were calculated by dividing the maximum concentration detected for each compound by the predicted no-effect concentrations. Three of the 42 compounds monitored (the pharmaceuticals carbamazepine and sulfamethoxazole and the herbicide simazine) had a hazard quotient >1, suggesting that they may be causing adverse effects at the most polluted sites. A further 10 compounds had hazard quotients >0.1, indicating a potential risk; these included four pharmaceuticals, three personal care products, and three pesticides. Most compounds had hazard quotients significantly <0.1. The number of TrOCs measured in this study was limited and further investigations are required to fully assess the risk posed by complex mixtures of TrOCs on exposed biota.

Model-based evaluation of reduction strategies for micropollutants from wastewater treatment plants in complex river networks

A model based on graph theory was developed to efficiently evaluate the impact of the effluent from 742 wastewater treatment plants (WWTPs) on micropollutant loading throughout all river catchments in Switzerland. Model results agree well with measured loads for 12 compounds in river water samples, revealing mean predictive accuracy factors between 0.8 and 3.4. Subsequently, pollutant concentrations were predicted for river sections downstream from 543 WWTPs where hydrological information was available, and compared with recent recommendations for water quality criteria. At base flow conditions, carbamazepine concentrations (parent compound only) are ubiquitously below a water quality criterion of 0.5 microg L(-1). In contrast, the sum of diclofenac and its metabolites is expected to exceed the corresponding water quality criterion of 0.1 microg L(-1) in 224 river sections. If diclofenac cannot be eliminated atthe source, the model suggests a directed upgrade of 173 WWTPs to meet the condition that concentrations are never to exceed this water quality criterion.

European case studies supporting the derivation of natural background levels and groundwater threshold values for the protection of dependent ecosystems and human health

The EU Water Framework and Groundwater directives stipulate that EU member states have to assess groundwater chemical status by the use of groundwater threshold values derived for the protection of dependent ecosystems and human health. This paper presents a synthesis of main results of 14 European case studies evaluating a methodology for derivation of natural background levels (NBLs) and groundwater threshold values (TVs) proposed by the EU research project "BRIDGE". The 14 investigated groundwater bodies were selected to represent as many aquifer types, climate settings and European ecoregions as possible within the project group that included partners from 17 EU countries. The selected case study sites include transboundary groundwater bodies, EU Pilot River Basins and other important groundwater systems. Some are known to interact with associated ecosystems, while others do not. The proposed method derives groundwater threshold values based on environmental objectives for dependent ecosystems or groundwater "itself" using relevant reference criteria such as natural background levels, environmental quality standards and drinking water standards. Derived groundwater threshold values for dissolved Cl and As applying drinking water standards as examples of reference values, are compared for all 14 case studies. Additionally, more detailed analyses are conducted for the Odense Pilot River Basin and the Vouga River Basin, where groundwater threshold values for N and P and Cl, As, Cd, Ni, Pb, and Zn, respectively, are derived based on environmental objectives and quality standards for groundwater dependent ecosystems. Results demonstrate that the proposed methodology is operational and may be used to protect human health and the environment. Further they show that groundwater threshold values derived from environmental objectives and environmental quality standards for dependent ecosystems in some cases may be significantly lower than drinking water standards, e.g. for nitrate.