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ODWAC-MOECC Strategy Workshop on Lead (Pb)

ODWAC-MOECC Strategy Workshop on Pb (Lead):  Agenda and Key Information

DATE:                                  February 10th, 2017, 9:30 AM to 3:30 PM

LOCATION:                       40 St Clair Ave W., 3rd Floor, Training Room “A”. 

KEY CONTACTS:            Scott Barrett, scott.barrett@ontario.ca, cell 416-994-7238                                          

OBJECTIVES:

To develop advice on what additional scientific, technological and economic analysis MOECC needs to undertake, if any, to adopt and implement the more stringent drinking water standard for Pb as proposed by Health Canada.

To determine if consultation with stakeholders and / or further discussion with Health Canada is warranted.

ATTENDEES:

All Members of ODWAC + MOECC/MOHLTC/PHO Staff

Invited MOECC Experts:

Jim Gilmore, SDB

Robert Dumancic, SDB

Aziz Ahmed, SDWB

Stephen Hetherington, SDWB

Agenda:

6 hour meeting, 30 minute lunch and two 15 minute breaks.

OVERALL APPROACH AND CONTEXT:  Jim Smith and Satish Deshpande (15 minutes)

 The premises for this workshop:

 1.      The Council accepts in principle Health Canada’s Proposal:

In considering both treatment and analytical achievability and the health risks associated with exposure to lead from drinking water, the Federal-Provincial-Territorial Committee on Drinking Water has proposed a MAC of 0.005 mg/L (5 µg/L) for total lead in drinking water, based on a sample of water taken at the consumer’s tap, using the appropriate protocol for the type of building being sampled. As this value exceeds the drinking water concentration associated with neurodevelopmental effects in children, every effort should be made to maintain lead levels in drinking water as low as reasonably achievable (or ALARA).

 

The Council will review the underlying science and policy for the recommended standard and identify any additional scientific, technological and economic analysis MOECC needs to undertake for Council to recommend that the guideline be adopted as an Ontario Drinking Water Standard and replace the existing ODWQS of 5 ug/L.  (Note from the Chair:  In framing our discussions think of the health based “bookend” as 0.08 to 0.008 ug/L and the ALARA “bookend” as 5 ug/L.  We will need to explain to the Minister the basis for these two “bookends” and what the gap means in terms of protection (and risks) to sensitive populations.)

 

2.       The discussion has been organized into 4 topic areas - each area with specific questions.  Information copied directly for HC’s document is highlighted in italics.  A summary of Council’s thinking to date is also summarized to aid discussion. Time limits have been prescribed for each area.  Ministry staff will be participating as Subject Matter Experts and the information they provide and views they express will not be attributed to the MOECC unless they state that is the case. The four topic areas are:

i             Health Assessment

ii            Exposure Assessment and Risk Characterization

iii           Risk Reduction Measures and Implementation

iv           Stakeholder Consultation and Follow up with Health Canada

 

3.       Jim Smith has agreed to facilitate the workshop.  There will be a written summary of key discussion points however comments and opinions will not be attributed to any specific individual without their express consent.  Scott Barrett will keep a running list of agreements, questions and issues on flipcharts as the workshop proceeds.

  

4.     Key documents that have been referenced by the Council are listed and hyperlinked in Appendix 1 at the bottom of this webpage.

 

 TOPIC AREA 1:   HEALTH ASSESSMENT (90 minutes)

Confirm Science and Toxicology:

Health Canada’s bottom line

1.      For  neurodevelopmental effects: (60 minutes)

Although it is generally accepted that neurodevelopmental effects are the key endpoint associated with exposure to lead, there is still some debate as to whether a change in IQ of 1 point can be considered “adverse”. Although a threshold for lead cannot be identified, extending the concept of linear extrapolation typically limited to genotoxic carcinogens is the only approach that is currently appropriate for use in this assessment. The only universally adopted acceptable levels of risk of 10−5–10−6 are for genotoxic cancer endpoints. As these risk levels would be considered overly conservative for an endpoint such as a small loss in IQ, an acceptable level of risk ranging from 10−4 to 10−5 may be considered appropriate in the non-cancer risk assessment of lead. This would correspond to concentrations ranging from 0.008 to 0.08 µg/L for lead in drinking water, based on children aged 5–11 years, identified as the most sensitive population.

 Although this assessment is extremely conservative, in part because of the approximate error rate of ± 3 in children’s IQ tests (Sattler, 2001), it provides an indication of the levels at which neurodevelopmental effects would become a consideration in the assessment of exposure to lead in drinking water.

In developing the MAC:

The proposed MAC will have a significant impact on the BLLs of children, the most vulnerable population. It is estimated that reducing the MAC from 0.01 to 0.005 mg/L would lower the geometric mean percentage of children with BLLs exceeding 5 µg/dL by 7.2 percentage points (from 9.4% to 2.2%). 

 

Q1:         Does Council support the basis for the risk assessment and the science policy decision made for a non-threshold approach to neurodevelopmental toxicity? 

 

(a)    If not what questions need to be answered? 

 

(b)   Can Council formulate direction to MOECC on how these questions should be addressed? 

 

(c)    Do these questions need to be answered before Council can recommend the guideline be adopted as an ODWQS?

 

 

COUNCIL DISCUSSION TO DATE:  Jim Gilmore and Jim Smith to lead discussion

Previous MOECC health assessment used a threshold approach and applied appropriate safety factors to develop a health based level that was considered protective.  Current thinking is Pb is an “essentially” non-threshold neurodevelopmental toxin.  Council did discuss key questions including:

Is there sufficient evidence that low BLL levels (1-2 µg/dL) are associated with adverse IQ/cognitive effects?  Have studies been conducted in this low range?

Is there sufficient Evidence of ADHD and neuro-behavioural effects in the low BLL range (1-2 μg/dL)?

A key science policy question is what is an appropriate “de minimis” health based level below which there is negligible health concern.  Options include:

·         Health Canada’s approach considered a 1 IQ point deficit as “adverse”, then extrapolated using a standard non-threshold (i.e. cancer) approach to recommend that a 1/10,000 to 1/100,000 of an IQ point is de minimis.

·         International and MOECC considered IQ point deficit as “adverse” then allocated a percentage of the 1 IQ deficit attributable to drinking water exposure using a standard cumulative/multimedia approach. Levels below this adjusted value are considered de minimus. Note: EFSA 2010 considered a decrease of 1 IQ point (i.e., 1% change in IQ) on full-scale IQ score as a benchmark response (BMR) because it was within range of observable values & would have impact on socioeconomic status of population & its productivity.

·         Also, US EPA and CalEPA consider 1 IQ point to be significant from a public health perspective International agencies and MOECC considered 0.5 IQ point deficit as de minimus. Note: WHO/JEFCA 2011 at the population level, a decrease of 3 IQ points was deemed to be a concern, whereas a decrease of 0.5 IQ points was considered to be negligible.

·         International and MOECC considerations that a delta (number to be determined) change to background blood lead levels in children is just discernable or de minimis. One approach could focus on determining a “threshold” level in drinking water that would result in a negligible increase in BLL (e.g. <0.1 µg/dL increase) given typical background exposures from dust, food, air.   

 Key Document(s): 1, 2, 3, 4, 5, 6, 7, 15

1.       For other Non-neurotoxicity Health Effects: (30 minutes)

 

Q2:         Do we need further review and analysis of other health effects arising from Pb exposures at very low levels?

 

(a)    Do these questions need to be answered before we can recommend the guideline be adopted as an ODWQS?

 

 

COUNCIL THINKING TO DATE:  Jim Gilmore, Satish Deshpande to lead discussion

Other health effects arising from Pb exposures at very low levels and within the range of levels for neurodevelopmental toxicity have been demonstrated.  These include carcinogenicity, blood pressure and other cardiovascular effects.  Further analysis is needed to better understand how these health effects should be taken into account in establishing a health based standard for Pb or whether a neurodevelopmental basis to a Pb standard is sufficiently health protective.

 Key Document(s): 7

  

TOPIC AREA 2:   EXPOSURE ASSESSMENT AND RISK CHARACTERIZATON (60 minutes) 

This is a complex area in terms of approach.  Three ways of looking at the populations exposed to Pb in drinking water from municipal supplies are: 1. the general population; 2. the population having their water delivered through lead service lines; and 3. the sensitive population (children and expecting mothers) having their water delivered through lead service lines.  The most insightful and robust model for analysis has been prepared by the City of Ottawa in estimating population exposures including the development of a Hi/Lo exposure scenario for sensitive populations (i.e. children).

 The MOECC protocol for determining the need for control strategies to reduce lead is key in understanding the populations for which community wide exposure reduction measures are required. Municipalities have basically two options to meet the regulatory requirements – corrosion control and lead service line replacement. Some municipalities like the City of Toronto have taken additional steps such as advising consumers that households with young children or expecting mothers should use end of tap filters to further reduce lead intake.  The Ministry has undertaken an analysis of municipalities that would need to develop Lead Control Strategies if a DW Standard of 5 ug/L is adopted.

  

 

Q3: Does Council continue to support MOECC’s protocol for determining the need for control strategies to reduce lead?  

 

(a)    Do we have sufficient information to understand how the distribution (i.e. curve) of lead concentrations across all lead service lines (partial and full) is shifted to the left in a community, thereby reducing Pb levels?

 

(b)   Can the Ottawa case study be extrapolated to other treatment systems to estimate exposure?

 

 Health’ Canada’s Bottom Line on the benefits of reducing the MAC:

·         The proposed MAC will have a significant impact on the BLLs of children, the most vulnerable population. It is estimated that reducing the MAC from 0.01 to 0.005 mg/L would lower the geometric mean percentage of children with BLLs exceeding 5 µg/dL by 7.2 percentage points (from 9.4% to 2.2%).

  

 

Q4: Does Council support the basis for the exposure estimates and risk characterization (i.e. benefits) estimated by HC?

 

(a)    Is this analysis robust enough to understand the benefits for and the risks to sensitive populations?

 

(b)   If not what questions need to be answered is there a better exposure and risk characterization model on which to make these decisions? 

 

(c)    Can Council formulate direction to MOECC on how these questions should be addressed? 

 

(d)   Do these questions need to be answered before Council can recommend the guideline be adopted as an ODWQS?

               

 

COUNCIL DISCUSSION TO DATE:  Ian Douglas, Jim Smith, Jim Gilmore to lead discussion

 Considerations:

A province wide exposure and risk characterization assessment using a model similar to the “Ottawa Case Study” would provide more robust information on which to base a decision of the benefits of a more stringent standard.  The analysis would provide estimates on the distribution of exposures for children in homes that have lead service lines.  Such an analysis would provide information on the benefits of a more stringent standard and also provide information on the level of urgency for action and the need for interim advice to consumers on steps they can take to reduce their exposure until corrosion control practices or lead service line removal actions have been taken.  

MOECC’s current policy for determining the need for Pb reduction for municipal residential drinking water systems continues to be supported by the Council. The current approach is based on specific requirements around sampling procedures (flushing, standing time, the volume and number of sequential samples collected etc.) and a prescribed statistical assessment of the analytical results.

Exposures from other media and sources (soil, air, food, and other incidental home exposures) also contribute to total exposure.  Council believes drinking water nevertheless is an important contributor. 

The characterization of risk is also dependent upon the science policy developed from the health effects assessment.  Some approaches in the USA look at cumulative IQ point loss for the population of children exposed.  The magnitude of the cumulative IQ point loss is highly dependent on what is considered de minimis and this measure of risk to a population is very new.

MOE’s exposure reduction strategy for Schools and Day Nurseries will provide an additional level of risk reduction for young children. 

Key Document(s): 2, 5, 10, 11, 12, 18

 

TOPIC AREA 3:  RISK REDUCTION MEASURES AND IMPLEMENTATION (90 minutes)

Health Canada bottom line (ALARA factors and use of filters): 

  • The MAC must be measurable. The U.S. EPA has established a PQL of 0.005 mg/L, based on the ability of laboratories to measure lead within reasonable limits of precision and accuracy using approved methods. There is no similar process in place to establish a PQL specific to Canada.

  •  The MAC must be achievable at reasonable cost. Municipal-scale treatment technologies can remove lead from drinking water; however, lead is mostly present in drinking water from leaching in the distribution and plumbing systems. Consequently, strategies for minimizing lead at the tap should focus on controlling corrosion and removing lead-containing components. The use of materials certified to the appropriate NSF/ANSI standards, such as Standard 61 (Drinking Water System Components—Health Effects) and Standard 372 (Drinking Water System Components—Lead Content), will help reduce the concentration of lead at the tap.     

  • As the primary source of lead in drinking water is the leaching from plumbing and distribution system components, a private residential drinking water treatment device, certified to the appropriate NSF/ANSI standard, is the best option for reducing lead concentrations in drinking water at the tap. However, the use of such devices should not be considered a permanent solution.

 

 

Q5:  Does Council support the HC’s basis for ALARA? 

 

(a)    If not what questions need to be answered? 

 

(b)   Can Council formulate direction to MOECC on how these questions should be addressed? 

 

(c)    Do these questions need to be answered before Council can recommend the guideline be adopted as an ODWQS?

 

 

COUNCIL DISCUSSION TO DATE:  Aziz Ahmed, Robert Dumancic, Ian Douglas, Jim Smith to lead discussion

As a first step Council held a Meeting of Experts, October 16th to discuss corrosion control in terms of the current state of the technology and challenges in implementation province wide.  MOECC invested considerable effort and time in 2007/8 in developing expertise on corrosion control and publish an extensive technical guidance manual for municipalities on the subject.  There are three strategies for reducing lead exposure from drinking water for municipal residential systems:

1.       Control Practices

2.       Lead Service Line Replacement

3.       Consumer actions to reduce exposure at the tap by flushing, the use of filters or using alternative drinking water sources

The first strategy require significant analysis in terms of the technologies available to reduce Pb and the costs associated with implementation for a range of source water types and current treatment approaches used in Ontario’s municipal residential drinking water systems.  The second strategy requires significant policy discussion in terms of acceptable timelines, costs and the role of the province, municipality and homeowner in lead service line replacement.  The third strategy requires policy direction from MOHLTC and PHO.

Council has discussed ALARA in the past.  It does not have a specified protocol on how ALARA is evaluated or how costs and technology limitations are assessed.  See Document 15.

Council does not support using a PQL of 5 ppm as limiting basis for establishing ALARA.  Lower limits for Pb can be achieved.  The PQL likely has not been reassessed and updated.

FOUR SHORT PRESENTATIONS TO PROMOTE DISCUSSION WILL BE DELIVERED AS FOLLOWS:

1.        ALARA – what does it mean and how does Council want to apply (Jim Smith/Scott Barrett)

2.       Ontario Experience with Corrosion Control Discussion (Aziz Ahmed, Ian Douglas)

A tale of Five Ontario Cities:  Will look at how five Cities have implemented lead reduction strategies.  Ottawa – Ian Douglas; City of Toronto, Hamilton and two smaller cities that have made reductions selected by Aziz Ahmed (Cities TBC)

  

3.       Corrosion Control Broader Discussion (Robert Dumancic)

We will have a broad discussion on the limits of corrosion control, with consideration of the following:

·         How far can corrosion control reduce Pb levels?   How are the challenges/issues different in using corrosion control to lower Pb from 10 ug/L to 5 ug/L vs. from 5 ug/L to 1 ug/L, below 1 ug/L? 

·         What are the key challenges (technological, retrofit issues, operational, cost) in implementing corrosion control?

·         What are the potential unintended consequences that can result from implementing corrosion control?

·         Perspectives on optimized corrosion control for small, medium and larger drinking water systems?

4.       Use of Filters and other risk reduction measures such as flushing (Jim Smith and Stephen Hetherington)

The City of Toronto has provided direction to its residents in steps they can take to reduce their exposure to Pb including the use of filters at the tap.  Council will discuss the City’s policy decision and the role of filters in the content of ALARA for the province.

  Key Document(s): 8, 9, 10, 11, 12, 14, 16, 17, 18

  

 

TOPIC AREA 4:      STAKEHOLDER AND PUBLIC CONSULTATIO STRATEGY INCLUDING HEALTH CANADA FOLLOW-UP (60 minutes)

 

 

Q6:  Need and benefits from focused or broader stakeholder consultations on science, technical and policy considerations in the development and implementation of the standard?  Options include:

 

(a)    Science and Science Policy discussions with recognized experts to discuss rationale for benchmarks for neurodevelopmental toxicity and application of a non-threshold approach similar to that used for carcinogens.

 

(b)   Technical and Technical Policy discussion with municipalities, possibly OMWA and OWWA, regarding the application of ALARA for LSLR, CC and other risk reduction strategies.

 

(c)    Policy direction discussion with the public and/or public interest groups such as CELA on the use of ALARA, including public responsibility for reducing exposure through measures such as point of use filters.

 

  

Appendix 1:  KEY DOCUMENTS TO DATE:

1)      Lead in Drinking Water Document for Public Consultation, Health Canada, January 2017

2)      Prevention of Childhood Lead Toxicity, American Academy of Pediatrics, July 2016

3)      Lead (Pb2+) Ion-mimicry with calcium (Ca2++) impairs synaptic transmission, Journal of Local and Global Health Science, April 2013

4)      Evaluation of Proposed New HBV for lead in Drinking Water, Ian Douglas, July 2016

5)      Lead exposure in a municipal water system: City of Ottawa Case Study, Ian Douglas September 2016

6)      Health Risk Assessment Perspective on the Federal proposed “Lead in Drinking Water”, Jim Gilmore, July 2016

7)      Other Health Effects of Lead, Ian Douglas & S. Deshpande, 2016

8)      Summary of Lead Experts Discussions in Ottawa, ODWAC, October, 2016

9)      Lead and Copper Rule Revisions White Paper, US EPA, October 2016

10)   Ontario’s approach to sampling and analysis to determine if a lead control strategy is required

11)   State of Lead Exposure in Ontario Drinking Water, SDWB, October 2016

12)   Status of Corrosion Control Strategies, SDWB, December 2016

13)   Use of filters and Other Risk Reduction Measures for Lead, City of Toronto & Satish Deshpande, 2017

14)   ODWQS Tenets and ALARP Tests, ODWAC, 2009

15)   Lead Toxicity - Drinking Water Presentation, Jim Gilmore, January 2017

16)   Corrosion Control Effectiveness Presentation, Aziz Ahmed, January 2017

17)   Understanding Corrosion Control in Drinking Water Presentation, Robert Dumancic, January 2017

18)   Flushing and Lead Testing for Schools (Reg. 243) Presentation, Stephen Hetherington, January 2017

19)   Strategies for Assessing Optimized Corrosion Control Treatment of Lead and Copper, JAWWA, Richard Brown, May 2013

20)   Risk calculation of HBV for lead in drinking water, Ian Douglas, April 2016

21)   Comparison of LSL Response: CC vs. pH vs. Phosphate, Ian Douglas, 2016

22)   Rough Utility Cost Estimates for Corrosion Control, City of Ottawa, Ian Douglas, February 2017

 

 

 

 

 


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