Water & Earth System WESSWESS Science Competence Cluster Calibration of Turbidity as a Proxy for the Transport of Hydrophobic Contaminants in Rivers Hermann Rügner, Marc Schwientek Water & Earth System Science (WESS), University of Tübingen, Germany Peter Grathwohl University of Tübingen, Germany Transport of hydrophobic pollutants (e.g. PAHs) Coupled to particles 3 ) Cw,tot = Cw(free) + Csus TSS -1 2 PAH15 (µg l (µg PAH15 1 w,tot C 0 0 10 20 30 40 50 Discharge Q (m3 s-1) 3 Data from River ) -1 Steinlach, Nov. 2012 2 PAH15 (µg l (µg PAH15 1 w,tot C Use of turbidity 0 (cloudiness) as proxy 0 500 1000 1500 2000 -1 Water & Earth System Science Suspended Solids TSS (mg l ) WESS Competence Cluster WESS catchments (SW Germany) Ammer (Pfäff) 134 km2 Land Use: Goldersbach 73 km2 Steinlach 140 km2 Echaz 133 km2 2 Neckar 2317 km Water & Earth System Science WESS Competence Cluster Sampling campaigns 1.5 years monthly sampling campaign (#300 samples) 2010-2012 mainly at catchment outlets (Ammer: + further locations) and variable discharge conditions (base flow … floods; 1 - 250 NTU) Event-based sampling (floods) with automatic samplers at selected gauging stations (#100 samples; 30 - 2200 NTU) 25 500 Q 20 400 Turbidity ) -1 15 300 s 3 10 200 Q (m 5 100 Turbidity (NTU) Turbidity 0 0 22.07.11 28.07.11 05.08.11date 12.08.11 19.08.11 Analysis: Turbidity, Total suspended solids (TSS) PAH (DOC, Ions, Particles,…) Water & Earth System Science WESS Competence Cluster Turbidity as a proxy for total suspended solids (TSS) monthly sampling Linear TSS-turbidity correlation 10000 -) slope (m) = 1-2.7 (mg l-1 NTU-1) Ammer Steinlach 1000 Echaz -) good agreement with Goldersbach literature data Neckar ) -1 100 Ammer Springs 10 TSS (mg l TSS (mg 1 TSS = 1.86 * Turbidity 0.1 0.1 1 10 100 1000 10000 Turbidity (NTU) Rügner et al. (2013): Environ. Earth Sci. 69(2),373-380. Water & Earth System Science WESS Competence Cluster Turbidity as a proxy for total suspended solids (TSS) monthly sampling plus event-based sampling Linear TSS-turbidity correlation 10000 -) slope (m) = 1-2.7 (mg l-1 NTU-1) Ammer Steinlach 1000 Echaz -) good agreement with Goldersbach literature data Neckar ) -1 100 Ammer Springs Established correlations 10 -) hold for high discharge TSS (mg l TSS (mg Steinlach Nov.12 events (> 2.000 NTU) 1 Ammer Nov.12/Jul.13 G.-bach Nov.12/Jul.13 -) are similar for all TSS = 1.86 * Turbidity Neckar Dec.12 0.1 catchments investigated 0.1 1 10 100 1000 10000 Turbidity (NTU) Turbidity may serve as a proxy for TSS in rivers Rügner et al. (2014): Sci. Total Environ. (accepted). Water & Earth System Science WESS Competence Cluster Turbidity as a proxy for total PAH concentration Monthly sampling campaigns Cw,tot = Cw + Csus * m * turbidity 100 Ammer Echaz Steinlach Neckar ) 10 -1 Ammer Spring Goldersbach ? ? 1 PAH15 (µg l (µg PAH15 0.1 W,tot C 0.01 0.001 0.1 1 10 100 1000 10000 0.1 1 10 100 1000 10000 turbidity (NTU) turbidity (NTU) Csus different for different catchments Ammer Echaz Neckar Steinlach A-Spring Goldersbach -1 Csus (mg kg ) 5.4 2.9 2.6 1.4 0.75 0.13 m (mg l-1 NTU-1) 2.7 2.4 1.5 1.7 1.0 1.4 Schwientek et al.(2013): Environmental Pollution, 172, 155-162. Water & Earth System Science WESS Competence Cluster Turbidity as a proxy for total PAH concentration Monthly sampling campaigns Events (floods; 30-2.200 NTU) Cw,tot = Cw + Csus * m * turbidity 100 Ammer Echaz Steinlach Neckar ) Goldersbach 10 A-Spring l-1 Neckar Dec.12 Ammer Jul.13 Goldersb. Nov.12 1 Ammer Nov.12 Goldersb. Jul.13 Steinlach Nov.12 PAH15 (µg (µg PAH15 0.1 W,tot C 0.01 0.001 0.1 1 10 100 1000 10000 0.1 1 10 100 1000 10000 Why is Csus differentturbidity (NTU) / catchment specific? turbidity (NTU) WhatEstablished are PAH correlation sources and predict pathways? high discharge events Ammer Echaz Neckar Steinlach A-Spring Goldersbach -1 Csus (mg kg ) 5.4 2.9 2.6 1.4 0.75 0.13 m (mg l-1 NTU-1) 2.7 2.4 1.5 1.7 1.0 1.4 Rügner et al. (2014): Sci. Total Environ. (accepted). Water & Earth System Science WESS Competence Cluster PAHs: Sources and Pathways Atmospheric deposition Urban/industrial areas Sewer system High PAH emission Run-off from urban surfaces Sewer overflow WWTP Rivers Water & Earth System Science WESS Competence Cluster What governs concentration of PAHs on suspended solids? X X Urban pressure/particle flux: (Schwarz et al.) (Meybeck at al.) Water & Earth System Science Schwientek et al.(2013): Environmental Pollution, 172, 155-162. WESS Competence Cluster Testing the hypothesis: Ammer River Measured concentrations (Ammer) -1 Csus (Ammer, suspended solids): 5.4 mg kg (this study) -1 CS MEAN (Ammer sediments): 8.6 mg kg (Liu, Rügner, Schwientek et al. 2013) Csus calculated from atmospheric deposition (Ammer, urban space) urban atmospheric deposition: 1 µg m-2 day-1 (Tübingen area, Gocht & Grathwohl 2004) urban area in Ammer catchment: 23 * 106 m² (Gauge Pfäffingen) mean load of TSS (2012): 3150 kg day-1 -3 -2 -1 6 2 1 ⋅ 10 [mg m day ] ⋅ 23 ⋅ 10 [m ] -1 C = Csus = 7.2 mg kg sus 3150 [kg day-1] Water & Earth System Science WESS Competence Cluster On-line Turbidity Measurements On-line turbidity sensors Q + turbidity curves (Steinlach, Feb.-Nov. 2012) 50 1200 Q 40 Turbidity 900 ) -1 30 s 3 600 20 Q (m 300 10 Turbidity (NTU) Turbidity 0 0 08.02.12 22.04.12 05.07.12date 17.09.12 29.11.12 Turbidity: few major events, usually discharge related These events should not be missed! Water & Earth System Science WESS Competence Cluster Short-Term Events and Pollutant Mass Flux Cumulative mass flux vs. turbidity Cumulative mass flux vs. time 100 100 75 80 60 50 40 25 20 Cum. Mass flux (%) flux Mass Cum. 0 (%) flux Mass Cum. 0 0 200 400 600 800 1000 1200 0 100 200 300 Turbidity (NTU) Time (days out of 295) High turbidity/discharge events account for major proportion of pollutant fluxes (90% PAH flux > 90 NTU) These are short-term events: 90% PAH flux within 7 days - out of 295 (< 2.5 % of observed time period) Water & Earth System Science WESS Competence Cluster Conclusions . Turbidity is an easy to monitor proxy for concentration of total suspended solids (TSS) and hydrophobic pollutants (e.g. PAH). Robust linear correlations of total PAHs versus turbidity (or TSS) are obtained. Slopes represent contamination of suspended particles.. …which are catchment specific and increase with urban pressure per sediment flux. On-line turbidity measurements are needed to obtain reliable estimates of pollutant fluxes because of short term turbidity events. Rügner et al. (2013): Environ. Earth Sci. 69(2), 373-380. Schwientek et al. (2013): Environmental Pollution, 172, 155-162. Rügner et al. (2014): Science of the Total Environment, 490, 191–198. Acknowledgement: WESS Cluster (funded by the Helmholtz-Centre for Environmental Research, UFZ, and the Ministry for Science, Research and Arts Baden-Württemberg GLOBAQUA Project (funded by the European Communities 7th Framework Program: Grant Agreement no 603629-ENV-2013-6.2.1) Water & Earth System Science WESS Competence Cluster Water & Earth System Science WESS Competence Cluster Landscapes export particles Discharges Erosion / Surface Runoff In-stream Processes Water & Earth System Science WESS Competence Cluster Sources: PAH concentrations in Ammer sediments 25 I. Ammer (main stem) II. TributariesTributaries with withpossible III. TributariesTributaries Ammer river with without overflows impactsewer of overflow without sewer 20 WWTP and SO sewer overflows dry weight] (SO) overflow (SO) 1 - 15 PAH15 [mg kg PAH15 10 S C 5 Ammer spring Ammer2 spring Ammer spring Ammer1 spring Goldersbach 0 Sampling site Strong PAH Ammer Tributaries Tributaries Ammer (mg/Kg) (channel) with SO without SO (all) heterogeneity of PAH concentrations Mean 13,4 5,8 2,1 8,6 Std.dev. 5,0 5,1 1,2 6,5 Urban source: Mean f_oc 2,5% 2,0% 1,9% 2,2% sewer overflows Schwientek et al.(2013): Environmental Pollution, 172, 155-162. Water & Earth System Science WESS Competence Cluster PAH Concentrations vs. Turbidy and Particle Size 100 Steinlach Nov.12 Ammer Lab 1 Ammer Jul.13 Ammer Lab 2 30 ) -1 G.bach Nov.12 Ammer Lab 3 G.bach Jul.13 Ammer Lab 4 Ammer Lab 5 10 20 1 10 g (µg PAH15/TSS Grain size d_50 (µm) (µm) size d_50 Grain w,tot C 0 0.1 10 100 1000 10000 0 10 20 30 Turbidity (NTU) Grain size d_50 (µm) PAH concentrations does not significantly change with particle size Rügner et al. (2014): Sci. Total Environ. (accepted). Water & Earth System Science WESS Competence Cluster PAH Distribution Patterns Ammer (12) Ammer sediments (16) 25 Echaz (1) Neckar (5) Steinlach (5) Körsch (5) 20 Goldersbach (8) Goldersbach sediments (1) 15 10 Single PAH (%) 5 0 Fln Ant Fth Py Any Ace Phe BaA Chr BaP Indeno DahA BghiP Bbf-BkF "PAH distribution patterns in sediment samples and liquid-liquid extracted samples (for TSS > 47 mg l-1 in Körsch or turbidity > 25 NTU in other catchments). Number of samples considered given in brackets." Schwientek et al.(2013): Environmental Pollution, 172, 155-162. Water & Earth System Science WESS Competence Cluster WESS catchments (SW Germany) Land Use: Ammer (Pfäff) 134 km2 2 Goldersbach 73 km Steinlach 140 km2 Echaz 133 km2 Körsch 129 km2 Neckar 2317 km2 Water & Earth System Science WESS Competence Cluster .