Øyvind Mikkelsen and Knut Schrøder SensAqua AS, Norway and

1. Automatic and Unattended Monitoring of Heavy Metals in Waters, with Long-term Stability of the Measurements and with no Toxic material needed Øyvind Mikkelsen and Knut Schrøder SensAqua AS, Norway and Norwegian University of Science and Technology (NTNU) Department of Chemistry Trondheim, Norway www.sensaqua.com Asia presentations 2013

2. Weather data - are collected by automatic weather stations and the results are transferred automatically to a central unit, frequently also available immediately to the public via Internet. But pollution data - are normally collected manually by field visits and the samples are then brought to laboratories for analysis. Several resources are spent annually for sample collection and laboratory analyses of heavy metals OUR METHODS OPEN FOR DOING MUCH OF THIS AUTOMATICALLY like what has been done for years in meteorology

3. Advantages • Possibilities to act immediately if the results exceed given threshold values • A great number of data will be available for processing • Low costs, then several sources can be monitored • If it is wanted, the data can be immediately available for the general public on the Internet For quality assurance, conventional sampling and analyses in a laboratory are performed from time to time for comparison.

4. Analyses can in general be performed in three different ways: • Samples are brought to laboratories to be analyzed with advanced instruments. A huge number of methods are available • Direct field single analyses. Paper strips methods are very convenient in addition to the use of simple instruments like pH-meters, photometers etc. • Continuous and on-line remote monitoring in the field. (dealt with in the present presentation)

5. An improved and more complete environmental monitoring program can be established by combining manually sampling - doing analyses in the laboratories and continuous monitoring in the field - using automatic equipment. Then it will be possible immediately to detect pollution, immediate action is possible - and the methods can mutually verify each other.

6. Any needs for monitoring, what is there already…? Norway; 139 rivers, 20 incineration plants, 2500 water purification plants. Europe …… USA; 5000 already existing stations where heavy metal monitoring may be implemented, 14400 mines, 4000 industrial plants, 54000 water purification plants Kina; 111 already existing stations where heavy metal monitoring may be implemented, 3000 industrial plants Japan;135 rivers, 55 lakes, 1,400 incineration plants, 3,000 sewerage treatment plants, 1,500 water purification plants. India; 72 already existing stations where heavy metal monitoring may be implemented Korea; about 350 stations where heavy metal monitoring may be implemented

7. Any needs for monitoring, where…? • water purification plants and rivers in metropolis • implementation in existing stations monitoring other environmental parameters • mining and metallurgical industry • construction work • incineration plants and waste industry • petroleum industry, offshore installations, and shipping • aquaculture • laboratories

8. How to monitor..? • Monitoring of environmental parameters are in general carried out with field sampling followed by analyses in a laboratory. • There are very limited possibilities to perform remote and automatic monitoring of waters and effluents, except from simple parameters, like pH and conductivity, which is a great drawback.

9. What can unattended be measured in waters? • Temperature • pH • COD, TOC and other major components • Conductivity • Turbidity and colour • Flow rate and water level • Some bacteria etc. But heavy metals are not on this list

10. Why are the heavy metals not on that list? But before this is answered: What kind of chemical methods are used for such monitoring?

11. Different methods for remote monitoring Even to perform reliable pH-measurements are quite difficult, but this is erroneously considered to be simple. Normally this is done by using potentiometric glass electrodes. An international quality assurance project for such measurements could be very useful. Temperature, turbidity, colour, flow rate, water level and other physical parameters can easily be monitored. Conductivity measurements are also in principle quite easy, but not as simple as found in catalogues from manufacturers for long-term use. Major components like nitrate, phosphate, hardness, COD, TOC etc. can easily be monitored by roboting laboratory analyses. Such roboting techniques are also worked out for monitoring of bacteria activities.

12. Different methods for remote monitoring…. The main problem in remote monitoring is when the concentrations are at trace levels - and too sophisticated instrumentation is required. This explains why heavy metals are not on the given list. The very great difference between having a method which works fine in a lab. Doing the same unattended and remotely in the field has to be emphasized. Too much published work is done in the laboratory only and then assumed to be adaptable to be used the field.

13. Requirements for remote monitoring • Long-time stability of the measuring system i.e. sufficiently long periods between required manual maintenance • Acceptable sensitivity • No use of toxic materials in the measuring system like liquid mercury and mercury salts • Not too expensive installation costs, this to allow installation of several units, and also considering that the remote installations might be stolen or destroyed • Presence of electricity (solar cells and batteries can be used if frost is not present) • Availability of Internet or another telecommunication system

14. How - and which methods can be used for monitoring of heavy metals? The advantages and drawbacks of electroanalytical methods… Voltammetry vs. potentiometry…

15. Overview of methods for heavy metal monitoring

16. In voltammetry we get information about the analyte by measure the current developing on the surface of an electrode as a consequence of a redox reaction. Here, the electrodes are essential - they sense the compounds to be measured.

17. Totally there are five requirements for making such automatic voltammetric analyses useful: • Sufficient high overvoltage to allow the measurements without interferences from hydrogen gas formation • Sufficient long term stability without need of maintenance • Sufficient sensitivity to allow monitoring of the pollutants • That non-toxic material is used (very important for off-laboratory methods) • Not too expensive material needed

18. The essential is to obtain long time stability, combined with sufficient overvoltage during the measurements to avoid the formation of hydrogen gas on the electrodes. This because the corresponding flow of current destroys the measuring signal. How to solve that…..?

19. How to find suitable electrodes which give sufficient overvoltage? Alloy electrodes! Liquid mercury or deposit of mercury film made from a mercury salt Solid and environmental friendly alloy sensors

20. Alloying a metal with high hydrogen overvoltage with a metal with low hydrogen overvoltage. A significant increase in the hydrogen overvoltage is observed for the alloyed metal, even for small additions (2–4 %).

21. The use of solid alloy electrodes cannot be new in voltammetry? Very astonishing this was never done before we did our first experiments in 1997. One explanation is possibly that it was believed in polarography/voltammetry that an electrode only worked properly being a one-component metal. Consequently nobody had tried. Later, and after our patenting, several publications appeared.

23. The new system has some interesting advantages: • Easy to implement in online apparatus • Non toxic • Stable over a long time without attendance • It can be used for detecting a range of different heavy metals

24. Actual measuring electrodes We use two different types of electrodes: Gold based alloys, for monitoring metals in the more positive potential range (like As) Silver based alloys, for monitoring metals in the more negative potential range (like Zn) In general we cannot use gold or silver alone because the lacking of overpotential for preventing hydrogen gas formation, and we cannot use the alloying metal alone because of passivation of such electrodes over time. We use solid and homogeneous electrodes and not film electrodes. This because film electrodes will require frequent replating, lowering the long-term stability between the need for physical attendance.

25. The methods have been patented internationally, and have been verified over a long time. • Our research started at Norwegian University of Science and Technology (NTNU) about 14 years ago, and the first patent was filed in 1998.

26. Cadmium Some examples Electrode system: Working E DAM Counter E Pt Reference E Ag/AgCl/KCl NH4Ac (0,05M)

27. Zinc Electrode system: Working E DAM Counter E Pt Reference E Ag/AgCl/KCl NH4Cl (0,05M)

28. Thallium Electrode system: Working E DAM Counter E Pt Reference E Ag/AgCl/KCl NH4Ac

29. Lead Electrode system: Working E DAM Counter E Pt Reference E Ag/AgCl/KCl HCl (0,01M)

30. Mercury Electrode system: Working E Au-Bi Counter E GC Reference E Ag/AgCl/KCl 10mM HNO3 + 10mM HCl

31. Tap water Solid line; real sample, dashed line; after addition of 100 g/l Zn, 50 g/l Pb and 500 g/l Cu. DPASV, dep. time 120 s at - 1450 mV, scan rate 15 mV/s, mod. pulse 50 mV. Supporting electrolyte; NH4Cl

32. AdCSV in seawater. HEPES buffer (pH=7.3), oxine (0.02mM), and DMG (0.3mM) added directly to sample. Dep. 120 s at -800 mV, scan rate 15 mV/s, mod. pulse -50 mV.

33. The SensAqua ATMS 500 Equipment The new version is SensAqua ATMS 600v3, but the principles are the same No liquid mercury No mercury salts No toxic materials X

34. This can be followed online at:www.sensaqua.com/ATMS The ATMS 500 (with two boxes)

35. New Electronics in ATMS 600v3 cell 2 cell 1 R C W R C W Fuse Xport(net) USB • 26-pin plug to the unit

36. ATMS 6011 v3 The new SensAqua ATMS 600 Equipment Inside the ATMS 600 v3

37. The new SensAqua ATMS 600 equipment compared with previous versions The chemical principles for the measurements are unchanged. Previously 230 V AC was used. The ATMS 600 uses 12 V AC (or adapter). This is advantageous if electricity is not available and solar cells or other sources are used. Previously we used two cabinets, one for the electrode system and one for most of the electronics and the industrial PC to be used for all data processing. In the ATMS 600 series, however, all the electronics is on a microprocessor card and a PC is not needed except from input and output of data and graphical presentation. Normally a laptop or network is used for such purposes. The ATMS 600 consists of one cabinet only, with less weight and easier to handle The ATMS 600 has • Higher stability over time by using a microprocessor card instead of the PC-processor • More simple maintenance because the card is the only to be replaced if needed • Increased sensitivity also because Square Wave Voltammetry is included • Less weight with one cabinet only • Higher stability because no computer is needed except from input and output of data and data processing. The PC can be operated remotely, and can be removed during running. What is new for the ATMS 600 version 3? The chemical principles used and the sensor system are the same, and the mechanical parts and the outer design are unchanged The electronics/microprocessor card is extensively redesigned to achieve improved sensitivity and stability The software (POS) is now also compatible with Windows 7 (32 or 64 bit) In addition to the previous automatic updating of the software, automatic updating of the firmware is also included. After being tested at by NEMKO (www.nemko.com), the version 3 in certified for the CE-marking

38. TBS HVS Løkken • Pilot projects in Norway:

39. From Raubekken

40. Calibration data from Raubekken

41. Zn Cu Fe Conc. added (mg/L) 250 250 220 Increase in peak height (mA) 21,7 16,0 23,1 Std. dev (mA) 1,3 1,5 1,2 Rel. std. dev (%) n = 8 6,0 9,6 5,2 Calibration data from Raubekken…..

42. Continuous analyses of zinc, iron, and copper for a time period of four months (middle of January to middle of May, 2004), in polluted river water (Raubekken) at Løkken Verk, Norway. The point in red are results from ICP-MS analyses. We can see from here that the speciation (of iron) is a very important factor.

43. Continuous remote monitoring of zinc, cadmium and lead. Scrubbing wastewater added NH4Cl (to 0.05M). DPASV, 120 s dep. time at -1300mV, scan rate 15 mV s-1, mod. pulse 50 mV. Heimdal incineration plant outside Trondheim

44. Continuous monitoring of mercury in purified scrubbing water at Heimdal incineration plant Trondheim, Norway.

45. An interesting new project:Forecasting of earth quakes Some indications show that there is an increase of the level of heavy metals in the groundwater prior to an outbreak of an earth quake. Automatic monitoring of heavy metals can then be used for such forecasting. A collaboration with geologists at University of Stockholm in Sweden is established to work out these new possibilities.

46. Some documentation Mikkelsen, Øyvind and Schrøder, Knut H.Dental Amalgam in Voltammetry - Some Preliminary Results. Analytical Letters 2000, 33, 15, 3253-3269. Mikkelsen, Øyvind and Schrøder, Knut H.Alloy electrodes with high hydrogen overvoltage for analytical use in voltammetry. Some preliminary results. The Analyst 2000, 125, 12, 2163-2165. Mikkelsen, Øyvind, Schrøder, Knut H. and Aarhaug, Thor A.Dental Amalgam, an Alternative Electrode Material for Voltammetric Analyses of Pollutants. Collection of Czechoslovak Chemical Communications 66, 3, 465-472 (2001). Mikkelsen, Øyvind and Schrøder, Knut H.Voltammetry using a Dental Amalgam Electrode for Heavy Metal Monitoring of Wines and Spirits. Analytica Chimica Acta. 458, 1, 249-256 (2002).

47. Mikkelsen, Øyvind and Schrøder, Knut H. Amalgam Electrodes for Electroanalysis. Electroanalysis (2003) 15(8), 679-687. Mikkelsen Øyvind, Skogvold Silje Marie, Schrøder Knut H., Gjerde Magne Ivar, Aarhaug Thor Anders Evaluation of Solid Electrodes for Use in Voltammetric Monitoring of Heavy Metals in Samples from Metallurgical Nickel Industry. Analytical and Bioanalytical Chemistry (2003) 377, 322-326. Mikkelsen, Øyvind and Schrøder, Knut H. Voltammetric Monitoring of Bivalent Iron in Waters and Effluents, using a Dental Amalgam Sensor Electrode. Some Preliminary Results. Electroanalysis (2004) 16(5), 386-390. Mikkelsen Øyvind, Nordhei Camilla, Skogvold Silje M., Schrøder Knut H. Detection of Zinc and Lead in Wine by Potentiometric Stripping on Novel Dental Amalgam Electrodes. Analytical Letters (2004) 14,37, 2925-2936.

48. Mikkelsen Øyvind, Skogvold Silje M. and Schrøder Knut H. Continuous Heavy Metal Monitoring System for Application in River and Seawater. Electroanalysis (2005), 17(5-6), 431-439. Mikkelsen Øyvind, Skogvold Silje M. SchrøderKnut H. Electrochemical Properties and Application of Mixed Silver-Bismuth Electrodes Electroanalysis, (2005) 17(21), 1938-1944. Mikkelsen Øyvind, van den Berg Constant M. G., Schrøder Knut H. Determination of Labile Iron at Low nmol L-1 Levels in Estuarine and Coastal Waters by Anodic Stripping Voltammetry. Electroanalysis, (2006) 18(1), 35-43.

49. Øyvind Mikkelsen, Kristina Strasunskiene, Silje Marie Skogvold, Knut Henning Schrøder, Camilla Constance Johnsen, Marion Rydningen, Patrik Jonsson, Anders Jonsson Automatic Voltammetric System for Continuous Trace Metal Monitoring in Various Environmental Samples. Electroanalysis 2007(19-20):2085-2092. Øyvind Mikkelsen, Kristina Strasunskiene, Silje M. Skogvold, Knut H. Schrøder Solid Alloy Electrodes in Stripping Voltammetry. Current Analytical Chemistry, (2008), 4(3), 202-205.

50. Conclusions and intentions Our method opens for new possibilities for environmental surveillance It has low costs and enables one to carry out water monitoring in a great number of water systems The pollution data can immediately be available to the general public e.g. via Internet Legal action can be taken immediately if irregularities appear in order to obtain better water quality and less polluted sewage systems Our intentions here are to introduce the new possibilities.