water.europa.eu Sensitivity analysis of the risk assessment for Zn based on monitoring data WG E Chemical Aspects Brussels June 2010 Helen Clayton / Jorge Rodríguez Romero WFD Team DG Environment, European Commission

water.europa.eu 2 Background Risk assessment of Zn reached conclusion (iii) for the aquatic environment Commission Recommendation on risk reduction measures for Zn: 2. The Member States should provide information to the Commission on the contribution of zinc sources and pathways to the aquatic environment, on possible controls and also on the levels of zinc in the aquatic environment, in order to consider possible inclusion of zinc in the next review of Annex X to Directive 2000/60/EC. Member States submitted a large amount of data in –20 Member States, ~ analysis Simplified prioritisation exercise based on monitoring (INERIS) resulted in “medium” ranking (i.e. risk ratio between 1 and 10) Concerns about quality of monitoring data were investigated (paper by INERIS/IOW – Link to CIRCA)Link to CIRCA Paper submitted by IZA based on the analysis of the country statistics (Link to CIRCA)Link to CIRCA Dossier prepared for the meeting of the Sub-Group on Review of May 2010 largely based on the analysis by IZA (Link to CIRCA)Link to CIRCA Comments and concerns raised by a number of Member States and DG ENV about the choices made as the basis for the IZA analysis (see e.g. NL comments part I and part II and BE comments)part Ipart IIBE comments

water.europa.eu 3 Purpose The purpose of the analysis presented here is to make a sensitivity analysis of the choices made to assess the risk of Zn based on the monitoring database, in particular of the choice of –The background values –The total/dissolved ratio –The bioavailability factor (BioF) The analysis will be based on the choices of the EU Risk Assessment Report (EU RAR) The result of the analysis will be displayed in maps showing the spread of the values below and above the PNEC

water.europa.eu 4 Background values EU RAR page 44 In the present report on zinc a pragmatic approach is followed rather than selecting one particular natural background value by using both the lower limit of 3 μg total-Zn/l and the upper limit of 12 μg total-Zn/l for correcting the available EU monitoring data in the risk characterisation. Therefore the range used for the sensitivity analysis will be 3 to 12 μg/l IZA paper uses the same range For dissolved, background values in the range of 1.1 to 4.4 μg/l are used, which result from the conversion of the 3-12 range using the Kp of 2.65 (see next slide)

water.europa.eu 5 Total/dissolved ratio As regards Kp, EU RAR page 41: In the present RAR the used Kp values between water and suspended matter […] [is] 110,000 l/kg (logKpsusp=5.04) [...]. In addition to these values also the impact of varying Kpsusp values on the results of the aquatic regional exposure assessment will be demonstrated […]. For this both the mean (110,000 l/kg), highest (176,000 l/kg) and lowest (64,000 l/kg) Kpsusp values from Venema (1994) will be used. As regards the suspended matter concentration Cs, EU RAR uses the TGD value (page 197): In the TGD a C susp of 15 mg/l is used for “standard” surface water (freshwater) This Cs value seems reasonable (even not conservative) looking at suspended matter data of European rivers (e.g. Therefore, the total/dissolved ratio used in this analysis is 2.65 (IZA paper uses 2.7) Total/Dissolved = [1+(Kp x Cs)] = 2.65, where Kp= l/kg and Cs=15 mg/l With Kp = and the values are 3.64 and 1.96

water.europa.eu 6 Bioavailability factor EU RAR page 325: An overall view on Table results shows that the average BioFwater for the various EU waters ranges from 0.3 to 0.9 and the realistic worst case BioFwater from 0.6 to 1.0. (see also table , page 330) The range taken for the sensitivity analysis is therefore 0.6 to 1.0 IZA paper uses 0.6 only

water.europa.eu 7 Spanish data IZA paper does not use the Spanish data as they were reported as “dissolved” but the samples are usually treated with nitric acid for stabilisation in the field Therefore, due to the acid treatment, some of the Zn associated with particulate matter would have dissolved, artificially increasing the concentration of the dissolved fraction Instead of disregarding all data (which is quite extensive), it was decided for this exercise to assume that the data reported represents total Zn instead of dissolved This results in an underestimation of the risks for Spain as the stabilisation will not result in the conversion of all Zn attached to particulate matter to dissolved, but only part of it

water.europa.eu 8 Results The following maps illustrate the results of the analysis This allows displaying the geographical spread of the stations that present concentrations higher than the PNEC values All analytical values (averages per station) are corrected with the values shown and then compared with the generic PNEC of 7.8  g/l Values above the PNEC are shown in red and below in grey In addition, the calculations were done on the basis of the P90 for each country, as in the IZA paper, but only for total Zn data This country by country analysis is the approach in the risk assessment reports

water.europa.eu 9 Bkg: 3/1.1 Tot/Dis: 2.65 BioF: %14%

water.europa.eu 10 Bkg: 3/1.1 Tot/Dis: 2.65 BioF: %68%

water.europa.eu 11 Bkg: 3/1.1 Tot/Dis: 2.65 BioF: %75%

water.europa.eu 12 Bkg: 12/4.4 Tot/Dis: 2.65 BioF: % 59%

water.europa.eu 13 Bkg: 12/4.4 Tot/Dis: 2.65 BioF: %66%

water.europa.eu 14 Bkg: 12/4.4 Tot/Dis: 2.65 BioF: %70%

water.europa.eu 15 Risk ratios per country Background values 3-12  g/l MS Nr of stations Nr of analyses90P Risk ratio (BioF 0.6) Risk ratio (BioF 0.8) Risk ratio (BioF 1.0) AT (0.18)0.11-(0.23)0.14-(0.29) BE CY CZ DK EE FR DE EL LT LU NL PT RO SK UK ES

water.europa.eu Risk assessment in the dossier Bkg 3-12, Kp 2.7, BioF 0.6, ES data not used 16

water.europa.eu 17

water.europa.eu Risk assessment in the dossier Justification of the BioF value of

water.europa.eu 19 Values reported in the EU risk assessment (table , ECB 2008). River50P DOC(mg/l)50P pH50P hardnessAverage BioF (recalculated with updated BLM) German rivers Aller Elbe Ems Main Mosel Mulde Oder Saale Saar Weser Average German rivers BE: Flanders BE: Wallonia NL: large lakes small lakes streams/brooks ditches spring Rhine Meuse NL average France Rhin Meuse Recent data (general water quality analysis; EA report 6484 (2005)) 0.6 NL STOWA report 2007 (216 regional waters) * NL Scheldt( ) NL Meuse ( ) ** *** FOREGS data (all Europe) See also Table 1 in IZA paper for this meeting (Link to CIRCA):Link to CIRCA

water.europa.eu 20 Comments The results are very sensitive to the values of the BioF The risk assessment states that the reasonable worst case is between 0.6 and 1.0 According to industry, recent developments of BLM models indicate that the value of 0.6 is conservative The risk assessment at EU level presented in the maps has to be interpreted with care as data from a few MS may weight a lot in the overall proportion of stations above PNEC The WG E is invited to –Discuss the results presented and the choices made –On the basis of all available information, advise whether Zn should be taken forward for EQS development or not