Presentation on theme: "NSF 60 - Purkiss December 2, 2009. Bromide Levels in Sodium Chloride AWWA / WRF Research Project conducted by the Southern Nevada Water Authority. –Surveyed."— Presentation transcript:
Bromide Levels in Sodium Chloride AWWA / WRF Research Project conducted by the Southern Nevada Water Authority. –Surveyed bromate, chlorate, perchlorate levels in bulk hypochlorite and on-site generator systems. –Submitted recommendations to NSF 60 Task Group on Perchlorate. –One recommendation was to establish in NSF 60 a maximum limit for Bromide levels in sodium chloride used in on-site electrolytic chlorine generators.
Bromide Levels in Sodium Chloride Goal would be to prevent the formation of excessive bromate levels from on-site generators. Another suggestion is to conduct an in-depth survey of OSG systems to measure amounts of bromate produced. Topic is beyond the scope of current task groups on perchlorate and bromate. Propose forming a task group to address issue and recruit: –NaCl producers –Electrolytic Chlorine Generator Manufacturers –Utilities that use on-site generation –Other interested parties
Task Group on Perchlorate in Sodium Hypochlorite
2006/7 NSF Survey Occurrence in NaOCl 82 samples of NaOCl were analyzed. 7 samples were ND. Samples ranged from ND to 300 ppm in product. Potential contribution to water was 28 ppb if the sample with the highest detection was used at its maximum use level.
NSF Survey Effect of Age on perchlorate in NaOCl
Perchlorate SPAC EPA issued draft Health Risk Level of 15ppb in 2008. Currently still a draft HRL. Final determination is delayed indefinitely. If 15ppb was set as a HRL or MCL, NSF 60 SPAC using 10% default values would be 1.5 ppb. If less than 10 sources are found to contribute perchlorate to drinking water a higher default percentage could be used. Currently 2 main sources known: –Contaminated groundwater –Sodium hypochlorite
Task Group on Perchlorate Charge to the Task Group: –Add perchlorate to the minimum test battery for all NaOCl products. –Add an analysis method to NSF 60 for perchlorate. –Develop a sampling and analysis program that takes into account the increasing concentration of perchlorate as NaOCl solutions age. For example developing guidelines for a maximum sample age for products evaluated to NSF 60. –Develop a listing footnote and labeling information to warn users of the occurrence of perchlorate in aged samples.
Task Group on Perchlorate Several members of Task Group were involved with AWWA/WRF-SNWA research project on occurrence of bromate, chlorate and perchlorate in hypochlorite. Developed a LC/MS/MS method for bromate,chlorate and perchlorate. Developed a predictive model to forecast chlorate and perchlorate concentrations is aged solutions of NaOCl. Report published in July 2009. Suggestions were made to the task group.
AWWA/WRF-SNWA Suggestions 1.Revise specification for on-site generator (OSG) salts. 2.Specify Best Management Practices and a maximum shelf life for hypochlorite. 3.Conduct a more in-depth survey of OSG systems and bulk hypochlorite storage, to validate predictive model. 4.Establish SPACs in NSF 60 for chlorate and perchlorate.
Development of Analytical Method Sub-task group on development of a perchlorate/chlorate method. Merged with task group on development of a bromate method. Southern Nevada Water Authority provided LC MS/MS method they developed for bromate, chlorate and perchlorate. Susan Anderson provided IC method that Olin uses for analysis of chlorate, perchlorate and bromate. IC method is more practical for production facilities to use.
Development of Analytical Method Round robin tests initiated between Olin, WQA, NSF, SNWA to validate LCMS and IC methods. Ideally both might be able to be referenced in NSF 60. TG is also identifying quenching agent to be used when sampling product to stop production of chlorate and perchlorate. Malonic acid is proposed.
Draft Requirements for Listing Footnote and Warning Labels 6.3.3 Perchlorate and chlorate in sodium hypochlorite sample 188.8.131.52 Manufacturers Use Instructions Aged solutions of sodium hypochlorite may contain elevated levels of chlorate and perchlorate. Certification Listings and the manufacturer’s use instructions that reference this Standard for hypochlorite products shall include the following statement: “Aged solutions of sodium hypochlorite may contain elevated levels of chlorate and perchlorate.” 184.108.40.206Production Dates and Repackaging Dates Products shall be labeled with the date of production, or the date of production shall be included on documentation supplied with bulk shipments. Products that are repackaged shall be labeled with both the production date and the date of repackaging, or this information should be included on documentation supplied with bulk shipments.
Develop a Program to Account for Increasing Concentrations of Perchlorate and Chlorate Idea # 1 – Let AWWA B -300 and the AWWA Chlorination Manual define best practices for storage and include predictive model for utilities to use. Limit NSF 60 to: –Sampling from oldest production lot at mfrs and repackagers. –Quench at sampling time. –Analyze and Certify to an established SPAC. –Let warning labels and Best Management Practices address the aging issues with chlorate and perchlorate.
Develop a Program to Account for Increasing Concentrations of Perchlorate and Chlorate Benefit of Idea # 1 –Certification has historically been for product as it is sold. –Mfrs and Repackagers cannot control how a product is stored or used. Drawback: –Utilities may assume certified product is contaminant free, and not be aware of best mgt practices, despite any warning labels.
Develop a Program to Account for Increasing Concentrations of Perchlorate and Chlorate Idea # 2 – Establish a predictive model based on initial product composition, assumed storage temperature, duration and dilutions based on best management practices. So that if initial concentration of perchlorate is below X, then we can safely say it is certified for use for Y days past born on date. This is what we are currently working on.
Develop a Program to Account for Increasing Concentrations of Perchlorate and Chlorate Benefit of Idea # 2 –Operator could confidently use product up to expiration/recommended use date. Drawbacks: –If storage conditions are much better than model assumptions, product may be suitable at a longer period of time than recommended use date. –If storage conditions are much worse than assumptions product will exceed levels prior to recommended use date.
Determination of a SPAC NSF 60 Annex A: -Use published risk assessments, or other available tox data. -Priority given to risk assessments from: -EPA -Health Canada -WHO -European Agencies -Other regulatory agencies, private sector.
Determination of a SPAC Several published risk assessments for perchlorate. Vary in degrees of magnitude <1-100. One reason EPA level is delayed. Most NaOCl used by utilities will contribute less than 1 ppb to drinking water, unless +10 weeks old. A pragmatic choice of an agency risk assessment with a realistic source contribution number might be the only way to establish a SPAC in the near future.
New York State Dept of Health Chemical Contamination Incident in 2008. –Petroleum contaminants. Source was a drum of NSF certified NaOCl. NSF audited the NSF 60 certified chemical distributor. –They had a quality plan for cleaning containers but did not have wash ticket system for each container. –NSF sampled a container at plant but subsequent analysis did not detect contaminants.
New York State Dept of Health NSF did not test sample of contaminated drum. NSF policies do not allow NSF to take enforcement action on samples that are not collected by NSF. NSF can and has tested samples for utilities on request – but cannot use these results for certification purposes.
New York State Dept of Health NSF was not able to validate complaint. NYS DOH feels NSF Certification Process and NSF Standard 60 do not adequately address contamination prevention and investigations. NY knows their complaint was valid. Why couldn’t NSF validate this? Propose recommendations for improving standard and certification process.
New York State Dept of Health 1.Amend NSF 60 to require tamper resistant/tamper evident seals on every container sold to public water suppliers. 2.Amend NSF 60 to require that all certified products be clearly labeled as being certified. 3.Mandate that wash slips be completed and maintained on file each time a re-useable container that has not been under the continuous secure control of the vendor is refilled. Do not accept written procedures as a substitute for wash slips.
New York State Dept of Health 4.Revise NSF complaint and audit procedures to ease policy based requirement that only product samples taken by NSF representatives be considered for NSF investigations. Consider providing an option for accepting samples taken under chain of custody by law enforcement, public agencies or their representatives.
New York State Dept of Health 5.Revise NSF contract so that results of audit reports can be made available to public health and consumer protection agencies without having to obtain the express consent of clients. Audit findings related to NSF 60 could reveal potentially acute public health concerns and delay to information exchange could delay needed response actions.