Accepted to JAWWA: 1

Transcription

1 Accepted to JAWWA: 1

2 Is there Cyanide in my Drinking Water? NO YES NO YES NO YES NO OUTLINE 2

3 Is there Cyanide in my Drinking Water? NO It wasn t mentioned in my Consumer Confidence Report (CCR) 3

4 Is there Cyanide in my Drinking Water? YES There s Something in Everything. 4

5 Delaney Clause 5

6 Mom-ism: 6

7 Is there Cyanide in my Drinking Water? NO Everybody Knows that Cyanide is acutely toxic, so it shouldn t be in my drinking water. However: Cyanide is present naturally in the blood. It doesn t bioaccumulate. It isn t known to be carcinogenic. It s lethal dose is about 4 mg/kg, so, at the current MCL of 200 ug/l, it would take about 525 L to drink the LD50. 7

8 Relative Lethal Doses Compared to HCN Less Lethal than HCN: HCN = 4 mg/kg Water Sugar Ethanol Caffeine 0.02 Cocaine 0.04 Fluoride 0.08 Heroin 0.18 LSD

9 Relative Lethal Doses Compared to HCN More Lethal than HCN: HCN = Strychnine 4 VX 7 Ricin 45 4 mg/kg Po ,000 Botox 1,000,000 9

10 Is there Cyanide in my Drinking Water? YES In EPA s recently released Third Six-Year Review, about 2% of the 119,659 individual Cyanide results from 49 states were positive, though only 0.07% were above the MCL. 10

11 Is there Cyanide in my Drinking Water? NO - Cyanide is rarely detected in untreated drinking water. In EPA s recently released Third Six-Year Review, 99.32% of 32,779 raw water results were NON-DETECT for cyanide. 11

12 Is there Cyanide in my Drinking Water? NO/YES/MAYBE Requirements by the States for Cyanide reporting may be unclear. For example: California: Report down to Detection Limit for Reporting (DLR) of 100 ug/l. New Jersey: Report down to the Detection Limits in 40 CFR Massachusetts: Not specified, but the edep reporting program accepts detection limits up to 100 ug/l. 12

13 Detection Limits for Cyanide From (a)(4) Methodology Detection Limit (ug/l) Distillation, Spectrophotometric 20 Distillation, Automated, Spectrophotometric 5 Distillation, Amenable, Spectrophotometric 20 Distillation, Selective Electrode 50 UV, Distillation, Spectrophotometric 0.5 Micro Distillation, Flow Injection, Spectrophotometric 0.6 Ligand Exchange with Amperometry 0.5 8/4/

14 What about the Alternative Test Methods for Cyanide From Appendix A? 8/4/

15 Is there Cyanide in my Drinking Water? YES - Clarifying guidance to Public Water Systems by EPA: If you are unsure of the MDL for a contaminant, and your laboratory reports a value greater than zero, include that in your CCR From EPA, 2010 Preparing Your Drinking Water Consumer Confidence Report: Guidance for Water Suppliers, 2nd Revision: EPA 816-R , April

16 Is there Cyanide in my Drinking Water? NO If a sample tests positive for chlorine there will be no free cyanide and the reaction between the two goes until one reactant is used up. (used without permission) 16

17 Cyanate by Ion Chromatography YES - Cyanate (CNO-) is observed in treated DW samples, implying that some cyanide was present at some time. Cyanate Peak 17

18 Cyanide (ug/l) Is there Cyanide in my Drinking Water? NO If there is residual chlorine, free cyanide goes away in a few hours ug/l spike 500 ug/l spike :00 0:12 0:24 0:36 0:48 1:00 1:12 1:24 1:36 1:48 2:00 2:12 2:24 18

19 Is there Cyanide in my Drinking Water? YES If there isn t residual chlorine, free cyanide can stick around for a month or more. 120 Percent of Original Recovered Raw Drinking Water Secondary Effluent NaOH Preserved Lab Fortified Blank Day

20 Is there Cyanide in my Drinking Water? MAYBE Over the first few days the free cyanide concentration can go up or down. 120 Percent of Original Recovered Raw Drinking Water Secondary Effluent NaOH Preserved Lab Fortified Blank Day

21 Is there Cyanide in my Drinking Water? NO it s FAKE CYANIDE! 21

22 Is there Cyanide in my Drinking Water? MAYBE - Cyanide is ephemeral. It comes and goes. 22

23 Is there Cyanide in my Drinking Water? NO Fake Cyanide can form when deionized water is treated like drinking water is treated and testing like cyanide samples are tested. 23

24 Simple Illuminating Experiment Routine Drinking Water Treatment: Deionized Water. Raise ph and Alkalinity (for corrosion control). Add hypochlorite (disinfection). Add ammonia (to form chloramine residual disinfectant). Routine Cyanide Sampling: Dechlorinate with ascorbic acid. Preserve with NaOH. Tests positive for Free CN by FIA/Amperometry : This is a problem! 8/4/

25 Is there Cyanide in my Drinking Water? NO Free Cyanide can form when deionized water is treated like drinking water, dechlorinated with ascorbic acid, and preserved with NaOH. 25

26 Is there Cyanide in my Drinking Water? NO Free Cyanide can form when deionized water is treated like drinking water, dechlorinated with thiosulfate, and preserved with NaOH. 26

27 A Possible Solution? On-site stabilization of a dechlorinated sample in a MICRO DIST tube. Or On-site distillation. The sample is acidified in the tube. Once the dechlorinated and acidified sample is sealed in the tube, any CN present is not allowed to escape. 8/4/

28 8/4/ MICRO DIST

29 Is there Cyanide in my Drinking Water? NO On-site distillation without NaOH was our fix in EPA said that was acceptable in 2007, but said it was unacceptable in This is an acceptable practice for wastewater. 29

30 Is there Cyanide in my Drinking Water? YES If you get a false hit for cyanide in your drinking water, there s not much you can do about it. 40 CFR doesn t give any leeway on preservation ask EPA! Thou shalt 30

31 Is there Cyanide in my Drinking Water? NO Maintain the integrity of samples by avoiding problematic steps. What can I do about it? Careful dechlorination, to reduce the residual chlorine without causing fake cyanide to form. Avoid NaOH, which can cause fake cyanide to form. Field Dilution, to reduce the effect of matrix. Field Spike, to show sample integrity was maintained. Same Day Analysis before the sample has a chance to change significantly. Use a Gentle Analysis Method (e.g. FIA). 31

32 ELAB Letter to EPA: 8/4/

33 ELAB Recommendations to EPA 1. We concur with EPA s conclusion stated in a recent Federal Register announcement that based on the assessments in EPA s Third Six- Year Review, there is only a low priority or no meaningful opportunity to lower the Cyanide MCL or MCLG from 200 µg/l. 2. EPA should acknowledge that false positives are possible when testing for cyanide using required methods and sample preservation. 3. EPA should clarify reporting requirements for detected contaminants in CCRs. 33

34 ELAB Recommendations to EPA 4. EPA should clarify the meaning of the cyanide Practical Quantitation Limit (PQL) of 100 µg/l 5. EPA should require that Free Cyanide results only be reported down to 100 µg/l in Consumer Confidence Reports. 6. EPA should clarify that Proficiency Test samples can be used for all forms of cyanide. 34

35 ELAB Recommendations to EPA 7. EPA should encourage reduced monitoring for cyanide when the PWS has no industrial sources of cyanide to minimize the possibility of obtaining false positive results caused by testing issues 8. EPA should clarify the terminology regarding detection and quantitation. EPA should clarify the requirements involving the various detection and quantitation terms: PQL, EQL, DL, MDL, MRL, LCMRL, LOD, LOQ, etc. 35

36 Cyanide Conclusions: A Modest Proposal Test for Free Cyanide, rather than Total Cyanide. Avoid NaOH to avoid cyanide formation. Be careful how samples are dechlorinated. Only report down to 100 ug/l. Same day analysis maintains sample integrity. Field dilution reduces matrix effects. Field spikes demonstrate sample integrity. 36

37 Thank you! Kevin Constantino for assisting in the lab work for this project. 37

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