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NSF 60 Revisions Purkiss. December 4, 2013. Update on Chlorate. SPAC established in NSF 60 – 2012 = 200 ppb. SPAC calculation did not utilize all sig figs of MAC risk assessment which would have resulted in a SPAC of 300 ppb. Rounding rules have now been clarified in NSF 60.

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Nsf 60 revisions purkiss

NSF 60 Revisions Purkiss

December 4, 2013


Update on chlorate
Update on Chlorate

SPAC established in NSF 60 – 2012 = 200 ppb.

SPAC calculation did not utilize all sig figs of MAC risk assessment which would have resulted in a SPAC of 300 ppb.

Rounding rules have now been clarified in NSF 60.

Ballot to correct SPAC passed the NSF 60 JC but failed the CPHC by 3 votes.


Update on chlorate1
Update on Chlorate

Correct derivation of SPAC based on 4 sources of chlorate

• source water

• hypochlorite

• chlorine dioxide or ozone

• one unknown source

  • SPAC = 1.12 mg/L = 0.28 mg/L = 0.3 mg/L (rounded)

    4


Update on chlorate2
Update on Chlorate

  • NSF International has tested 127 hypochlorite samples from Jan-Oct 2013.

  • 85 samples passed 200 ppb limit.

    • 65 Mfrs and 20 Repackagers.

  • 42 samples failed 200 ppb limit.

    • 9 Mfrs and 33 Repackagers.

  • 33% of samples failed for chlorate

  • 12% of samples from manufacturers failed.

  • 62% of samples from repackagers failed.


Update on chlorate3
Update on Chlorate

  • 18 failures are between 201-300 ppb.

  • 12 failures are between 301-400 ppb.

  • 5 failures are between 401-500 ppb.

  • 2 failures are between 501-600 ppb.

  • 4 failures are between 601-700 ppb.

  • 1 failure is between 800-900 ppb.

  • 43% of failed samples are in disputed range of 200-300ppb.


Reduction in max use level in terms of ppm total chlorine
Reduction in Max Use Level in terms of ppm total chlorine

  • Most hypochlorite products are listed at a MUL that equates to a total dose of 10 ppm chlorine.

  • Reducing MUL for products failing for chlorine would result in the following:

    # ProductsChlorate ppbReduced Chlorine MUL

    18 201-300 7 ppm

    12 301-400 5 ppm

    5 401-500 4 ppm

    2 501-600 3 ppm

    4 601-700 2 ppm


Chlorate spac
Chlorate SPAC

  • If the chlorate SPAC was properly set at 300ppb it would reduce the failures from 42 (33%) to 24 (19%). Resulting MUL reductions as follows:

    # ProductsChlorate ppbReduced Chlorine MUL

    12 301-400 7 ppm

    5 401-500 6 ppm

    2 501-600 5 ppm

    4 601-700 4 ppm


Chlorate spac1
Chlorate SPAC

  • Chlorate formation continues at significant levels in distribution, storage and handling to point of use.

  • Compliance with the chlorate standard has to be a shared responsibility between producers, distributors and end users.

  • AWWA standard provides recommendations to control chlorate levels through temperature control, dilution on receipt, inventory turns, etc.

  • Therefore control should be focused on user practices as AWWA recommends.


Chlorate spac2
Chlorate SPAC

  • 2013 data indicates that implementation of the current SPAC for chlorate could severely impact the user population.

  • Recommend to re-ballot SPAC correction to 300 ppb.



Bromate spac
Bromate SPAC

  • Table D1: the drinking water regulated level (MCL/MAC) for bromate should be changed from 0.01 mg/L to 0.010 mg/L to conform to the number of significant figures reported by the US EPA in the derivation of the MCL.

  • The SPAC for bromate should consequently be changed from 0.005 mg/L (5 ppb) to 0.0033 mg/L (3.3 ppb) based on the 0.010 mg/L MCL and derivation per Annex G and rounding rules.


Bromate spac1
Bromate SPAC

  • The SPAC for bromate referenced in 6.3.2.1 should be reduced from 5 ppb to 3.3 ppb as noted above.

  • The SPAC for “low bromate” in 6.3.2.2 should be lowered from 3 ppb to 1.0 ppb.

  • Alternatively “low bromate” could be removed from the standard.

  • Annex G should be deleted, as it announced the lowering of the SPAC for bromate effective January 1, 2013, and so is no longer needed. Replace with a note describing what it addressed.


Hypochlorite literature requirements
Hypochlorite Literature Requirements

  • If the MUL for a hypochlorite product is lowered due to a bromate failure section 6.3.2.1 of the standard currently requires a statement in manufacturer’s literature stating that the MUL has been lowered and why.

  • NSF 60 does not require this for any other product or contaminant other than bromate in hypochlorite. It also goes above and beyond product requirements and is addressing a certification practice. Therefore this should be removed from the standard.


Hypochlorite literature requirements1
Hypochlorite Literature Requirements

  • Section 6.3.3 contains requirements for manufacturer’s literature regarding the use of hypochlorite with respect to controlling the amount of chlorate and perchlorate. This requirement should be restricted to literature that references NSF 60, and not all literature that might accompany a shipment.


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