Metals in water and foams from NOM-rich sub-alpine streams

Metals in water and foams from NOM-rich sub-alpine streams Ola Sæther 1, Donald Macalady 2, Øyvind Mikkelsen 1, Shafia Iftekhar 1, Ånund Killingtveit 1 1 Geological Survey of Norway (NGU) Trondheim Norway 2 Colorado School of Mines (CSM) Golden Colorado United States 3 Norwegian University of Science and Technology (NTNU) Trondheim Norway

BACKGROUND River water consists of organic matter from terrestrial and aquatic sources. The terrestrial natural organic matter (NOM) has been subject to physicochemical reactions during transport, e.g. sorption and redox reactions, which affect and possibly homogenize the chemical composition of NOM. Change towards a warmer and wetter climate is assumed to intensify leaching of NOM in sub-alpine environments. This may affect the chemical composition of natural waters and increase costs of water treatment.

INTRODUCTION We have studied metal transport in a dozen tributary streams of lake Jonsvatnet, - the water supply for the city of Trondheim (pop.160 ), NO, by analyzing samples of water and foams floating on the streams. All streams are brown-water streams with elevated concentrations of aqueous natural organic matter (NOM). The NOM content varies seasonally and with episodic rainfall events and annual snow melt.

Trondheim City Jonsvatnet

Quaternary geological map of Jonsvatnet. Source: Reite (1983)

METHODS Fourteen different locations in the Jonsvatnet catchment were selected for which 11 were sampled frequently (i.e. 22x during Aug 07- May 08). More than 350 samples of water and 40 of foam were collected and analyzed. - NOM content Determined as concentration of dissolved organic carbon (DOC) on filtered samples (0.45µm) in mgc/l - SUVA(Specific UV-Absorbance @254nm ) a) Water samples analyzed w/simadzu UV mini 1240 UV-Vis spectrometer on liquid samples in 1.0cm quartz cell in L/mgC b) Foam samples were diluted 10x with deionized water to concentrations yielding a maximum absorbance less than one. - ph a) Standard glass electrode w/radiometer Copenhagen phm80 b) and after adding 1g of NaNO 3 to the water sample. - EC (Electrical Conductivity) Radiometer Analytical Ion Check 30 in liquid sample in μs/cm - Metal content 35 major, minor, and trace metals were determined for each sample using ICP-MS in mg/l.

Sample Periods and Sites For a better interpretation results were distributed in periods: Period 1: August and September Period 2: October and November Period 3 : February Period 4: Spring (March, April and May)

Site 1 SITE 1 Period 1 Period 2 DOC (mgc/l) 13.2 7.7 Abs 254nm (1.0cm cell) 0.507 0.308 SUVA (L/mgC) 0.0377 0.0398 ph (w NaNO3) 5.79 6.78 Conductivity (ms/cm) 50.9 63.5 Discharge (L/s) 225 64

Site 4 SITE 4 Period 1 Period 2 Period 3 Period 4 DOC (mgc/l) 9.9 11.9 8.1 6.7 Abs 254nm (1.0 cm cell) 0.41 0.418 0.337 0.295 SUVA (L/mgC) 0.041 0.04 0.039 0.044 ph (w NaNO3) 6.35 6.74 6.59 6.64 Conductivity (ms/cm) 55.5 56.7 48.4 44.6 Discharge (L/s) 344.6 765 1233.5 209

Site 5 SITE 5 Period 1 Period 2 Period 3 Period 4 DOC (mgc/l) 7.9 7.7 7.5 5.7 Abs 254nm (1.0cm cell) 0.363 0.321 0.29 0.242 SUVA (L/mgC) 0.045 0.042 0.038 0.042 ph (w NaNO3) 6.32 6.52 6.64 6.5 Conductivity (ms/cm) 67 44.3 44 40.6 Discharge (L/s) 124 309.3 896 121.7

Site 6 SITE 6 Period 1 Period 2 Period 3 Period 4 DOC (mgc/l) 6.9 6.2 5.4 4.7 Abs 254nm (1.0cm cell) 0.282 0.241 0.205 0.201 SUVA (L/mgC) 0.041 0.04 0.038 0.042 ph (w NaNO3) 6.05 6.82 6.64 6.42 Conductivity (ms/cm) 87.6 75.2 69.3 53.8 Discharge (L/s) 222.5 282.7 692 155.6

Site 7 SITE 7 Period 1 Period 2 DOC (mgc/l) 7 5.45 Abs 254nm (1.0cm cell) 0.243 0.296 SUVA (L/mgC) 0.035 0.086 ph (w NaNO3) 6.52 6.53 Conductivity (ms/cm) 75.1 59.1 Discharge (L/s) 74.5 132

Site 8 SITE 8 Period 1 Period 2 DOC (mgc/l) 12.9 10.4 Abs 254nm (1.0cm cell) 0.463 0.386 SUVA (L/mgC) 0.036 0.037 ph (w NaNO3) 5.48 6.51 Conductivity (ms/cm) 54.3 61 Discharge (L/s) 11 15.7

Site 9 SITE 9 Period 1 Period 2 DOC (mgc/l) 10 8.2 Abs 254nm (1.0cm cell) 0.4 0.344 SUVA (L/mgC) 0.04 0.042 ph (w NaNO3) 6.38 6.97 Conductivity (ms/cm) 67.6 109 Discharge (L/s) 31 47

Site 10 SITE 10 Period 1 Period 2 DOC (mgc/l) 10.6 9.5 Abs 254nm (1.0cm cell) 0.477 0.375 SUVA (L/mgC) 0.045 0.039 ph (w NaNO3) 5.74 6.66 Conductivity (ms/cm) 54.6 41 Discharge (L/s) 55 55

Site 11 SITE 11 Period 1 Period 2 Period 3 Period 4 DOC (mgc/l) 10.2 5.9 5.9 4.6 Abs 254nm (1.0cm cell) 0.407 0.2216 0.218 0.123 SUVA (L/mgC) 0.039 0.039 0.037 0.041 ph (w NaNO3) 6.64 6.73 6.68 6.35 Conductivity (ms/cm) 77 82.8 67.1 59 Discharge (L/s) 197.8 231 750 80.4

Site 11 A SITE 11A Period 1 Period 2 DOC (mgc/l) 10.3 9.9 Abs 254nm (1.0cm cell) 0.484 0.407 SUVA (L/mgC) 0.048 0.041 ph (w NaNO3) 6.86 6.95 Conductivity (ms/cm) 74.5 69 Discharge (L/s) 75.5 113

Site 13 SITE 13 Period 1 Period 2 Period 3 Period 4 DOC (mgc/l) 6.4 5.4 5 Abs 254nm (1.0cm cell) 0.246 0.199 0.142 SUVA (L/mgC) 0.039 0.036 0.04 ph (w NaNO3) 7.04 7.02 6.92 Conductivity (ms/cm) 184.9 139.8 126.2 Discharge (L/s) 119.6 363

Some general observations (all streams) Highest value (period) Lowest value (period) DOC 1 4 Abs (254 nm) 1 4 SUVA 4 3 Discharge 3 4 ph 2 1 Conductivity 1 / 2 4

NOM mgc/l NOM trends NOM (x,t) 20 18 16 14 Falling trend with time of year 12 10 8 NOM1 NOM2 NOM3 NOM4 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 11 11A 12 13 14 Site NOM concentration in mgc/l as function of period at the different sampling sites.

Flow (l/s) NOM mgc/l NOM (mg C/L) vs. Flow (L/s) NOM (x,t) 20 15 10 NOM1 NOM2 5 0 0 1 2 3 4 5 6 7 8 9 1400 10 11 1211A 13 14 Site NOM3 NOM4 Flow (x,t) 1200 1000 NOM; highest in period 1 and lowest in Period 4. Flow highest in Period 3 and lowest in Period 4. 800 600 400 Period 1 Period 2 Period 3 Period 4 200 0 11A 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Site

SUVA (L/mg C) 0.0600 0.0550 0.0500 0.0450 SUVA1 SUVA2 SUVA3 SUVA4 0.0400 0.0350 0.0300 11A 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 SUVA highest in period 1 and 4

Metals vs. DOC in water

Foam studies

Correlations in foam Site 1 Cd114 (1) Hg220 (1) Pb208 (1) Mg25 Al27 (1) Si30 P31 S34 (1) Ca43 Mn55 (1) Fe57 (1) Cu63 (1) Zn67 (1) As75 (1) Cd114 (1) Hg220 (1) -0.2 Pb208 (1) 0.5-0.8 Mg25-0.5 0.9-0.8 Al27 (1) -0.6 0.9-0.9 1.0 Si30 0.5-0.8 0.5-0.9-0.8 P31-0.9 0.1-0.6 0.4 0.5-0.2 S34 (1) -0.6 0.9-0.9 1.0 1.0-0.8 0.5 Ca43-0.5 1.0-0.9 1.0 1.0-0.9 0.3 1.0 Mn55 (1) -0.3 0.3-0.8 0.3 0.5 0.1 0.7 0.5 0.3 Fe57 (1) -0.5 0.9-0.9 1.0 1.0-0.9 0.4 1.0 1.0 0.3 Cu63 (1) -0.1 0.8-0.9 0.7 0.7-0.3 0.3 0.8 0.7 0.8 0.7 Zn67 (1) 0.6-0.8 1.0-0.9-1.0 0.7-0.6-1.0-0.9-0.6-0.9-0.8 As75 (1) -0.4 1.0-0.9 1.0 1.0-0.8 0.3 1.0 1.0 0.4 1.0 0.8-0.9 Correlation greater then ± 0.75 in approx 60% of all relations Correlation greater then ± 0.5 in approx 80% of all relations foam samples collected over a period of approx 5 weeks

Correlations in foam Site 4 Cd114 (1) Hg220 (1) Pb208 (1) Mg25 Al27 (1) Si30 P31 S34 (1) Ca43 Mn55 (1) Fe57 (1) Cu63 (1) Zn67 (1) As75 (1) Cd114 (1) Hg220 (1) -0.3 Pb208 (1) -0.4 0.8 Mg25-0.4 0.9 0.9 Al27 (1) -0.4 0.7 0.8 0.9 Si30-0.2 0.9 0.9 0.7 0.5 P31-0.2 0.8 0.8 0.9 1.0 0.6 S34 (1) -0.4 0.8 0.9 1.0 1.0 0.7 1.0 Ca43-0.3 0.7 0.8 0.9 1.0 0.6 0.9 0.9 Mn55 (1) -0.3 0.7 0.7 0.7 0.8 0.6 0.9 0.8 0.8 Fe57 (1) -0.4 0.7 0.8 0.9 1.0 0.6 1.0 1.0 0.9 0.8 Cu63 (1) -0.2 0.8 0.9 0.8 0.6 0.9 0.7 0.8 0.7 0.5 0.6 Zn67 (1) 0.7 0.0-0.1-0.1-0.1 0.1-0.1-0.1 0.1-0.1-0.2 0.2 As75 (1) -0.4 0.8 0.9 1.0 1.0 0.7 1.0 1.0 1.0 0.8 1.0 0.7-0.1 Correlation greater then ± 0.75 in approx 51% of all relations Correlation greater then ± 0.65 in approx 64% of all relations Correlation greater then ± 0.5 in approx 74% of all relations Foam samples collected over a period of 10 weeks

Relations foams vs. water 21.8.07 28.8.07 4.9.07 14.9.07 AVG STDEV RSD % 22.10.07 1.11.07 8.11.07 AVG STDEV RSD % Cd114 (F) 1.22 0.52 0.38 0.40 0.74 0.20 3.61 Cd114 (S) 0.137 0.031 0.020 1.029 0.020 1.364 0.198 8.9 16.6 19.3 0.4 11.3 8.5 75.2 36.0 0.1 18.2 18.1 17.9 99.0 Hg220 (F) 0.36 0.48 0.25 0.29 0.01 0.10 0.01 Hg220 (S) 0.050 0.027 0.011 0.008 0.0054 0.0075 0.0038 7.1 17.8 23.8 36.0 21.2 12.1 56.9 2.6 13.7 2.1 6.1 6.6 107.3 Pb208 (F) 4.74 5.96 6.42 2.87 0.80 2.03 0.62 Pb208 (S) 1.068 0.430 0.665 0.741 0.074 0.269 0.104 4.4 13.8 9.7 3.9 8.0 4.7 59.2 10.8 7.5 5.9 8.1 2.5 30.9 Mg25 (F) 2233.94 3606.04 3601.21 2859.84 1450.00 1585.00 969.00 Mg25 (S) 1 003 794 745 865 894 707 764 2.2 4.5 4.8 3.3 3.7 1.2 32.2 1.6 2.2 1.3 1.7 0.5 28.8 Al27 (F) 614.85 2798.91 3199.95 1341.90 684.00 903.80 321.70 Al27 (S) 27.2 115.5 131.8 128.1 111.0 138.3 113.9 22.6 24.2 24.3 10.5 20.4 6.7 32.6 6.2 6.5 2.8 5.2 2.0 39.5 Si30 (F) 1854.63 1784.25 1437.75 1261.35 764.00 899.70 893.00 Si30 (S) 861 766 797 920 1 173 1 012 1 018 2.2 2.3 1.8 1.4 1.9 0.4 22.1 0.7 0.9 0.9 0.8 0.1 16.6 Ca43 (F) 14697.93 30836.27 34610.52 16776.90 16152.00 11128.00 9537.00 Ca43 (S) 6 239 4 825 4 582 5 283 5 095 4 173 4 461 2.4 6.4 7.6 3.2 4.9 2.5 51.3 3.2 2.7 2.1 2.7 0.5 19.4 Fe57 (F) 1109.74 10036.72 9902.56 4596.53 750.60 2078.40 595.20 Fe57 (S) 127.8 181.0 214.8 186.7 185.6 196.8 169.3 8.7 55.4 46.1 24.6 33.7 21.1 62.6 4.0 10.6 3.5 6.0 3.9 64.9 Cu63 (F) 85.00 67.99 82.57 25.98 6.23 8.71 6.99 Cu63 (S) 4.07 2.85 2.56 14.18 0.89 4.09 0.67 20.9 23.9 32.3 1.8 19.7 12.9 65.3 7.0 2.1 10.4 6.5 4.2 64.0 As75 (F) 2.26 7.56 7.11 3.24 0.62 1.63 0.49 As75 (S) 0.35 0.28 0.28 0.28 0.253 0.336 0.233 6.4 26.8 25.4 11.4 17.5 10.2 58.0 2.4 4.9 2.1 3.1 1.5 48.3 51.5 51.9 P1 P2 Relation between concentration of Cd, Hg, Pb, Mg, Al, Si, Ca, Fe, Cu, and As in the foam and stream in period 1 and 2.

Overall factors Rel val global Cd114 2.5 Pb208 12.6 Al27 14.4 Si30 1.0 P31 72.0 S34 4.8 Mn55 19.6 Fe57 20.8 Cu63 10.0 Zn67 6.6 As75 8.8 Hg202 15.6 Mg25 2.3 Ca43 3.1 All foam samples collected related against water samples in same period

NOM production (mg C/L) Water samples: Average 7.79 ± 0.11 Plant extracts: Feather moss Sphagnum moss Spruce Cones Spruce Needles Sorbus (Ash) Willow (Alaskan) Alder Birch(European) Bamboo 1.6 2.4 9.0 15.4 21.4 23.5 31.0

SUVA (absorbance/mg C/L) Feather moss 0.032 Sphagnum moss 0.041 Spruce cones 0.022 Spruce needles 0.006 Sorbus (ash) 0.008 Willow 0.013 Alder 0.008 Birch 0.016 Bamboo 0.040

SUVA of Natural Waters: Streams and Rivers 1. Streams entering Jonsvatnet, Norway, 250 samples of 13 sites over 8 months: 0.0402 ± 0.0047. Range 0.0249-0.0577 2. Other Central Norway streams, 8 sites, 1 sample each: 0.0401 ± 0.0045. Range 0.0312-0.0456 3. Other rivers and Streams, 10 samples worldwide: 0.0407 ± 0.0079. Range 0.0252-0.0508

Conclusions SUVA values for natural waters are typically around 0.04 L/mg C. Of the plant extracts analyzed, only the mosses have equivalent SUVA values. Despite a much lower NOM production per unit biomass, mosses may be the more important contributors to the long-term NOM reservoirs in the streams.

Conclusions (cont d) Period 3 (Winter) has the lowest values for SUVA, and period 4 (spring) has the highest SUVA value but the lowest DOC concentration. Foams acts as metal collectors in environmental systems and seems to be of importance through the mobility of metals as metal transporters. Fe, Mn, Al, Pb and Hg are in general 15 20 times higher in the foams compared to concentrations found in the streams.

Thank you for your attention!