1. Analysis of the monitoring data intercomparability for the Bulgarian – Romanian common stretch of the Danube River PP2 – National Administration Romanian Waters Carmen Hamchevici

2. Sub-activity 5.2 Water quality analysis for laboratory intercalibration Long-term Short-term Momentary TNMN data QA/QC analysis 2014 (9 months) Individual sampling June 2015 Common sampling (not bulk sample!)

3. (1) Long term data comparability 2 transboundary sections (ends of the common BG-RO Danubian stretch):  Pristol / Novo Selo (river km 854) and  Chiciu / Silistra (river km 375) 4 selected water quality parameters:  nutrients forms (N-ammonium, N-nitrates, P- orthophosphates, Total Phosphorous) Period of time: 1996 – 2011 Raw data from TNMN database (the TNMN data management center in the Slovak Hydrometeorological Institute, acknowledged)

4. Prior to data comparability: Analytical Quality Control (AQC) organisation of interlaboratory comparison in the Danube monitoring: agreed in 1992 based on a list containing reference and optional analytical methods Provider: (until 2012) the Institute for Water Pollution Control of VITUKI, Budapest, Hungary Name of the scheme: QUALCO DANUBE (4 distributions / year) Inventory of analytical methods used and performances (Technical Report)

5. Methods Entire datasets provided by BG and RO to ICPDR database Selected datasets based on the simultaneous sampling days during 1996 – 2011 Statistical approach STATISTICA 10.0 (StatSoft. Inc., 2005):  Basic statistic descriptives number of values, minimum, maximum, mean, median, confidence intervals for mean – 95%, lower and upper quartiles – percentiles of 25 and 75 respectively, percentiles of 10 and 90 respectively, range and standard deviation  t-test between two independent variables (BG and RO): powerful parametric test, but with strong limitations related to distribution and variance  Box-plots (graphical representation)

6. Entire datasets: number of annually results produced by BG and RO at Pristol / Novo Selo transboundary section for N-NH4 N-NO3, P-PO4 and Total P (1996 – 2012)

7. Basic descriptive statistics – Pristol / Novo Selo (all data) PARA M. COU NTR Y VALI D N MEA N CONF. - 95% CONF. + 95% MEDIANMIN.MAX.P25P75P10P90 RANG E STD.DE V. N-NH 4 BG1100,160,130,180,140,000,860,080,220,030,300,860,12 RO1730,230,200,260,190,021,320,120,300,050,451,300,17 N-NO 3 BG1111,481,361,601,390,374,611,071,900,772,214,240,64 RO1731,241,161,311,150,232,840,871,560,661,942,610,50 P-PO 4 BG950,0650,0570,0720,0600,0000,2500,0400,0800,0200,1100,2500,035 RO1730,0780,0720,0840,0700,0120,2700,0500,1000,0320,1300,2580,041 TP BG820,1470,1050,1900,1000,0401,6000,0820,1410,0680,2001,5600,194 RO1660,1170,0930,1400,0900,0181,9300,0700,1300,0530,1701,9120,151

8. T-test: the null hypothesis of H 0 : μ x = μ y (p=0.05) BG VS RO MEAN GROUP 1 MEAN GROUP 2 t- VALUE DFp VALID GROUP 1 VALID GROU P 2 F-RATIO VARIANCE S p VARIANCE S N-NH 4 0,160,23-3,792810,0001821101731,960,000175 N-NO 3 1,481,243,572820,0004201111731,630,004089 P-PO 4 0,0650,078-2,6632660,008210951731,3130,144475 TP 0,1470,1171,3722460,171338821661,6480,007285

9. Box-plots (Pristol / Novo Selo – all data)

10. Basic descriptive statistics – Pristol / Novo Selo (simultaneous data) PARA M. CO UN TRY VALI D N MEA N CONF. - 95% CONF. + 95% MEDIA N MIN.MAX.P25P75P10P90 RAN GE STD.D EV. N-NH 4 BG 200.080.060.110.070.020.260.040.120.020.140.240.06 RO 200.250.170.330.210.020.640.150.320.040.540.620.17 N-NO 3 BG 211.571.331.80 0.752.701.101.900.832.021.950.52 RO 211.361.171.541.210.792.091.101.770.921.891.300.40 P-PO 4 BG 220.060.0550.0750.060.0200.1100.0500.0800.0400.0800.090.022 RO 220.060.0510.0880.060.0200.2200.0500.0800.0300.1100.200.041 TP BG 120.110.0880.1380.110.0510.1800.0920.1350.0600.1700.120.039 RO 120.120.0800.1770.110.0500.3300.0850.1600.0530.1700.280.076

11. T-test: the null hypothesis of H 0 : μ x = μ y (p=0.05) BG VS RO MEAN GROUP 1 MEAN GROUP 2 t- VALUE DFp VALID GROUP 1 VALID GROUP 2 F-RATIO VARIANCE S p VARIANCE S N-NH 4 0.080.25-4.07380.0002220 0.060.17 N-NO 3 1.571.361.47400.1499521 0.520.40 P-PO 4 0.0650.069-0.448420.6566822 0.0220.041 TP 0.1130.129-0.649220.5230512 0.0390.076

12. Box-plots (Pristol / Novo Selo – simultaneous)

13. Pristol / Novo Selo PARAM. COU NTRY VAL ID N MEANMEDIANMIN.MAX.P25P75P10P90RANGE STD.DEV. Water temp. RO 915.518.06.025.09.019.06.025.019.07.2 BG 916.117.03.326.69.622.53.326.623.38.6 SS RO 952.435.029.0152.033.036.029.0152.0123.041.1 BG 973.370.055.090.068.082.055.090.035.011.7 DO RO 98.67.86.111.17.69.76.111.15.01.7 BG 98.37.85.612.17.39.55.612.16.52.0 pH RO 98.07 7.928.218.028.127.928.210.290.09 BG 97.477.407.017.927.367.527.017.920.910.29 Cond. RO 938536634645736341834645711139.7 BG 938837534845136842034845110334.9 (2) Short – term data comparability January – September 2014 - 1

14. PARAM. COU NTRY VALI D N MEANMEDIANMIN.MAX.P25P75P10P90RANGESTD.DEV N-NH 4 RO 90.0530.0510.00600.17100.02900.05300.00600.17100.1650.04719 BG 90.0890.0720.03000.18300.04900.09200.03000.18300.1530.05649 N-NO 3 RO 90.0200.0220.01000.02900.01300.02500.01000.02900.0190.00723 BG 90.019 0.00500.03200.01800.02700.00500.03200.0270.00950 N-NO3 RO 91.0560.9800.55001.64000.83001.45000.55001.64001.0900.37290 BG 91.2961.2001.03001.64001.10001.47001.03001.64000.6100.24269 TOTAL N RO 91.5581.4480.78602.24001.19402.01800.78602.24001.4540.51179 BG 91.6711.5001.20002.50001.30001.90001.20002.50001.3000.45057 P-PO4 RO 90.0360.0370.01200.07000.02200.04800.01200.07000.0580.01779 BG 90.0390.0340.02200.05500.03200.05300.02200.05500.0330.01241 TOTAL P RO 90.0510.0490.02400.07500.04000.06500.02400.07500.0510.01685 BG 90.0680.0560.03600.16900.04250.07150.03600.16900.1330.04314 (2) Short – term data comparability January – September 2014 - 2 Pristol / Novo Selo

15. T-test: the null hypothesis of H 0 : μ x = μ y (p=0.05) BG VS RO (MIDDLE) MEAN GROUP 1 MEAN GROUP 2 t-VALUEDFp VALID GROUP 1 VALID GROUP 2 F-RATIO VARIANC ES p VARIAN CES w.temp. 15.50016.077-0.1543160.8792991.45370.609 SS 52.44473.333-1.4669160.16179912.2970.001 DO 8.55008.28880.29718160.7701991.45570.607 pH 8.06777.47225.81390160.00009910.2500.003 Cond. 385388-0.1765160.8620991.29940.719 N-NH 4 0.05380.0890-1.4310160.1716991.43320.622 N-NO 2 0.02000.01960.08377160.9342991.72720.456 N-NO 3 1.05671.296-1.6175160.1253992.36070.245 N Total 1.55801.67111-0.4976160.6254991.29010.727 P-PO 4 0.03600.0395-0.4643150.6490982.05510.358 P Total 0.05100.0681-1.1031150.2871986.55170.016

16. Pristol / Novo Selo 2014 – Water temperature

17. Pristol / Novo Selo 2014 – Suspended Solids

18. (3) Momentary data comparability - June 2015 Chiciu / Silistra Pristol / Novoselo

19. First approach

20. Performance analysis Compliance checking: QA/QC Directive (2009/90/CE) criteria - EQSs set-out by the 2013/39/EC

21. Conclusions on data comparability Higher degree of comparability for simultaneous sampling days (same hydrological regime) Good comparability for short-term and momentary data (2014 and 2015) Differences: Need for bilateral discussion (sampling, preservation, storage and analysis) Technical performances to be analysed vs the QA/QC Directive Future steps : bilateral agreement in place and operational common sampling (bulk sample) intercomparison exercises with agreed frequency on-table discussions on obtained results

22. Contacts Thank you for your attention! www.cbcromaniabulgaria.eu Investing in your future! Romania-Bulgaria Cross Border Cooperation Programme 2007-2013 is co-financed by the European Union through the European Regional Development Fund