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Establishment of a list of chemical parameters for the revision of the Drinking Water Directive ENV.D.2/ETU/2007/0077r Claus Jørgensen, DHI Helle Buchardt Boyd, DHI John Fawell, Independent consultant Owen Hydes, Independent consultant Stakeholder consultation DG Env. 6 May 2008
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Objective “The objective of this study is to guide the Commission by identifying the new set of chemical parameters and limit values for the revision of the Directive identified by the DWS. This study must capture the spectrum of available information, taking into account scientific evidence and implementation documents and present a list of chemical parameters for the revision.”
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Methodology Phase 1: prepare a long list of candidate chemical parameters for the possible inclusion in the Directive and the reasons for their possible inclusion (or exclusion). Phase 2: study of toxicological information on the candidate chemical parameters, propose a limit value and give preliminary views on inclusion in the revision of the Directive, Phase 3: prepare firm recommendations on the matrix of chemical parameters to be considered for inclusion in the revision of the Directive, the limit value or range of values for each, set out recommendations for monitoring based on drinking water safety plans being incorporated in the Directive,
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Status and time schedule
Phase 1: Phase 1 report delivered 3rd of March including parts of phase 2. Candidate list prepared based on information from the current Directive, Member States, various EU documents, Weknow, WHO and other countries standards (US, Can, NZ, Aus, J), stakeholder consultation etc. Suggestion to a new structure of annex 1 taking DWSP into account Phase 2/Phase 3: Merged together because: Time schedules pushed forward, preliminary draft final report by 25 April 2008. Toxicological assessment of important parameters complete Recommendations on parameter limit values, monitoring groups, and on dealing with small supplies Phase 3: Draft final report by 7 July 2008 – toxicological assessments complete –final recommendations.
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Purpose of limit values
To protect public health To ensure drinking water acceptable to consumers To provide reassurance to consumers. Could include political limit values such as pesticides. To provide a benchmark for water supply operations. To provide a benchmark against which to judge compliance with limit values.
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General requirements Selection of parameters needs to reflect real need. Real value in inclusion. Limit values need to be soundly based and derivation transparent to ensure that if limit value exceeded the response will be appropriate and consumer confidence not undermined. Need to consider practical/cost implications, particularly for small supplies and historical pollution.
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New developments Best practice has changed with introduction of Drinking Water Safety Plans (DWSPs). Source to tap hazard identification, risk assessment and risk management. Allows more specific targeting of monitoring while maintaining high standard of quality and health. Provides means of dealing with parameters or groups of parameters for which no appropriate means of monitoring. Proactive about preventing contamination and failure.
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Recommendation - new structure for annex 1
Core group of parameters that must be specifically included in national standards and indicator values and for which there should be a requirement to monitor or to demonstrate, by risk assessment and chemical analysis, that they are not present in the raw water or drinking water. 1A Parameters significant for public health and of high consumer concern. These parameters are in annex 1B of the current directive. Failures must be investigated and action taken e.g. Arsenic and pesticides 1B Parameters significant for acceptability to consumers and as indicators of drinking water quality These parameters are in annex 1C of the current directive. Failures must be investigated but action only required if risk to public health e.g. Iron, colour 2 Parameters, substances and groups of substances that would be identified and controlled by drinking water safety plans (DWSP) 2A Substances that need not be monitored if the hazard identification and risk assessment show that they will not occur. e.g. Chlorinated solvents, DBPs 2B Substances to be controlled under the DWSP approach, for which no appropriate analysis exist e.g. Endocrine Disrupting Compounds, most algal toxins 2C Substances that arise from the chemicals and materials in contact with drinking water, to be controlled by product specifications and use e.g. Acrylamide, vinyl chloride
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Discussion Points There are concerns regarding the proposed grouping of parameters. What are the concerns? What are stakeholders’ views and what would be appropriate?
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No of Member States Reported Problems
Parameter a b Arsenic 8 Chlorite 2 Nitrite 7 5 Aluminium 4 Chromium Nitrate 13 3 Ammonium Chloride Oxidisability Antimony Colour Pesticides 11 Boron Fluoride 10 Sodium Bromate Iron Sulphate Cadmium Lead THMs 6 Copper Manganese Turbidity Chl Solvents Nickel pH Raw water problems – a; other problems – b Any clarification?
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No of Member States suggesting new and deleted parameters
Chlorate 7 Microcystin 5 Manganese 2 Min Total Hardness Uranium 4 Calcium Chlorite Zinc 3 Corrosivity Delete Selenium 11 Cyanide 6 1,2-dichloroethane 2 Epichlorohydrin 9 Mercury Arsenic Acrylamide 7 Vinyl chloride 5
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Provisional list of parameters to delete
Directive Comments Benzene 1.0 µg/l Not normally in drinking water. However in DK: found in 26% of 891 groundwater samples, 0.2% above 1 µg/l. May also be found during emergency when contamination. Cyanide 50 µg/l Not normally in drinking water. Only found if industrial contamination 1,2 dichloroethane 3 µg/l Chemical intermediate and solvent rarely if ever found. Use DWSP Mercury 1 µg/l Not normally in drinking water. However, in DK: 36% of 132 samples average 0.1 µg/l, 2 above 1 µg/l Aldrin, dieldrin, heptachlor, and –epoxide 0.03 µg/l Include in pesticides parameter with the parametric value of 0.1 µg/l for each Total Pesticides 0.5 µg/l Not meaningful. Oxidisability 5 mg/l O2 Not useful as European wide requirement Sulphate 250 mg/l Not useful as European wide requirement. Selenium? 10 µg/l Proposed value in group 2A: 30 µg/l (10-50 µg/l dependent on local dietary intakes) Tritium 100 Bq/l Not meaningful for drinking water
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Discussion points Are these deletions appropriate?
Should selenium be added to the list of deletions? Should any others be deleted?
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Provisional list of parameters to add
Table 6 Possible values Comments Chlorite 0.3 to 1 mg/l ‘Disinfection BP’, don’t compromise disinfection. Suggest 0.7 mg/l Chlorate 0.3 to 0.7 mg/l ‘Disinfection BP’, present in sodium hypochlorite, don’t compromise disinfection. Suggest 0.7 mg/l Chloroacetic acids Disinfection conditions that may reduce THMs can encourage formation of chloroacetic acids. Other authorities have regulated. Need to seriously consider adding Total chloroacetic acids µg/l(would replace single HAAs) Assuming effects are similar and additive, suggest 80 µg/l as max. Uranium 15 – 30 µg/l WHO value of 15 µg/l likely to go up on review. Important for small supplies.
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Discussion points Are these appropriate to add for European wide standards? Are there other parameters that should be added – such as radon, Microcystin LR?
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Sampling points and frequencies
We propose to adopt the standard and enhanced frequencies recommended by sampling group as minimum frequencies Are these frequencies and sampling points appropriate – see next slide? In subsequent tables – are standard and enhanced frequencies for different parameters appropriate? How do we deal with small supplies – see later slide for proposals?
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Minimum frequency no/year
Sampling frequencies Volume m3/d Minimum frequency no/year Standard Enhanced <10 Small supplies sampling 10 – 100 1 4 ,000 12 1, ,000 1 + 1 for each 3,300 m3/d 12 +3 for each 1,000 m3/d 10,000 – 100,000 3 +1 for each 10,000 m3/d >100,000 for each 25,000 m3/d
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Group 1a Parameter Proposed limit value Current limit value
Sampling point Minimum Frequency Comments Arsenic 10 µg/l Works Standard Enhanced If removed Boron 1.2 – 2.4 mg/l 1.0 mg/l Cadmium 3 – 10 µg/l 5 µg/l Taps Copper 2.0 mg/l Fluoride 1.5 mg/l Lead Nickel ? µg/l 20 µg/l Enhanced? Nitrate 50 mg/l Nitrite 0.2 mg/l mg/l 0.1 mg/l 0.5 mg/l If chloram Pesticides 0.1 µg/l
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Discussion points Are these limit values appropriate?
If structure retained are these parameters appropriate for group 1A? Should any parameters be added from, or removed to other groups?
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Group 1b (Indicator parameters)
Proposed value Current value Sampling point Minimum Frequency Comments Aluminium 200 µg/l 100 µg/l 10y Works Taps Enhanced If used or removed Ammonium 0.5 mg/l Standard Chloride 250 mg/l Saline intrus Colour Acceptable Op at works Conductivity No change 2500 µS/cm Hydrogen ion ≥6.5 ≤9.5 pH Iron 100 µg/l 200 µg/l10y Manganese 50 µg/l If removed Odour
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Group 1b (Indicator parameters)
Proposed value Current value Sampling point Minimum Frequency Comments Sodium 200 mg/l Works Standard Saline intrus Taste Acceptable Taps Enhanced Total Organic Carbon No change Taps? Standard? Turbidity at works 1.0 NTU 0.5 NTU 10y Op at works Turbidity at taps Total Indicative dose 0.1 mSv/y Monitor gross α (< 0.1 Bq/l) and gross β (< 1 Bq/l)
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Discussion points Are these indicator values appropriate ?
If structure retained are these parameters appropriate for group 1B? Should any other parameters be added from, or removed to other groups?
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Group 2a (DWSP parameters)
Proposed value Current value Sampling point Minimum Frequency Comments Bromate 10 µg/l Works Taps Standard If ozone or NaOCl used NaOCl dist Chlorate 0.7 mg/l - If ClO2 or NaOCl used Chlorite If ClO2 used Total halo-acetic acids 80 µg/l If Cl2 or NaOCl used Total trihalo- methanes 100 µg/l Chromium 50 –100 µg/l 50 µg/l Fittings Selenium? 30 µg/l Consider deleting?
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Group 2a (DWSP parameters)
Proposed value Current value Sampling point Minimum Frequency Comments Tetrachloro-ethene 40 µg/l 10 µg/l* Works Standard Some ground-waters only Trichloro-ethene 10 µg/l Radon 100 µg/l Preliminary suggestion - Taps Uranium 15 – 30 µg/l Mostly groundwater * 10 µg/l for the sum of tetrachloroethene and trichloroethene Plus any other substance shown by DWSP at risk of being present assessed against WHO guideline value or other internationally recognised value
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Discussion points Assuming the structure is accepted are these parameters and their limit values appropriate? Should any be moved to other groups? Should any be added or deleted?
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Group 2b (DWSP parameters)
Proposed value Current value Sampling point Minimum Frequency Comments Endocrine disrupting chemicals - Barriers Pharma-ceuticals Phthalates PAH (total of 4 named PAH) 0.1 µg/l Taps If coal tar linings Benzo-a-pyrene µg/l 0.01 µg/l Cyanobacterial toxins Microcystin LR Works ?? µg/l
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Discussion points Is this acceptable?
What changes if any might be appropriate? Any parameters or groups of parameters/substances that should be added/removed?
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Group 2c (DWSP parameters)
Proposed value Current value Sampling point Minimum Frequency Comments Acrylamide µg/l 0.1 µg/l Polyacryl-amide coagulants Epichloro-hydrin 0.1 – 0.4 µg/l Polyamine coagulants Pipe coating Vinyl chloride 0.3 – 0.5 µg/l 0.5 µg/l PVC pipes Styrene - ABS pipes Possible to include chlorite and chlorate. Controlled by product specification and product use (dosage etc)
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Comparing the number of parameters of current Directive and the proposed changes
Annex or monitoring group 1B 1C 1A No of parameters 26 15 10 14 2A 2B 2C 7 4
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Discussion points If structure is acceptable, are these parameters and their limit values appropriate? Should any parameters be added or removed, e.g. chlorite?
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Monitoring small supplies
Considerable difficulties – monitoring long list of parameters expensive and not useful Need different approach Recommend monitor for at taps twice/year Conductivity Hydrogen ion (pH value) Turbidity E coli Any parameter identified by DWSP at taps/works Small supplies <10m3/d or <100m3/d ??
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Conclusions Proposal for evolution of chemical parameters.
Ensure resources are used in the most efficient way. Concentration on understanding and prevention that will lead into catchment and treatment control. Need reporting system that requires member states to show they have followed the rules.
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